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The impact of PPARγ and ApoE gene polymorphisms on susceptibility to diabetic kidney disease in type 2 diabetes mellitus: a meta-analysis

Abstract

Background

Globally, diabetic kidney disease (DKD) has become the leading cause of end-stage renal disease, imposing substantial social and economic costs. This meta-analysis was designed to provide valuable insights into gene-disease interactions by investigating the potential association between lipid metabolism gene polymorphisms and the risk of DKD.

Methods

An electronic literature search was conducted on MEDLINE Complete, Web of Science, Embase, and PubMed. A total of 18 studies on the peroxisome proliferator-activated receptor γ (PPARγ) Pro12Ala variant and 20 publications concerning apolipoprotein E (ApoE) gene polymorphism were included in the meta-analysis.

Results

Overall, the PPARγ Pro12Ala polymorphism was found to be significantly associated with a decreased DKD risk (OR = 0.74, 95% CI: 0.62–0.88). In subgroup analysis, Ala carriers were less susceptible to DKD than Pro homozygotes among Asian (OR = 0.73, 95% CI: 0.56–0.95) and Caucasian populations (OR = 0.74, 95% CI: 0.59–0.93). Subgroup analysis stratified by albuminuria categories showed that the PPARγ Pro12Ala polymorphism reduced the risk of both microalbuminuria and macroalbuminuria with corresponding ORs of 0.58 (95% CI: 0.43–0.78) and 0.68 (95% CI: 0.53–0.86). Sensitivity analysis confirmed the robustness of the meta-analysis results. However, publication bias was identified in the subgroup analysis of the Caucasian population. The primary analysis of the ApoE gene polymorphism yielded significant findings, indicating that ApoE ε2/ε2, ApoE ε2/ε3, and ApoE ε2/ε4 genotypes increase the risk of DKD (ε2/ε2 vs. ε3/ε3: OR = 1.93, 95% CI: 1.03–3.61; ε2/ε3 vs. ε3/ε3: OR = 1.63, 95% CI: 1.19–2.25; ε2/ε4 vs. ε3/ε3: OR = 1.87, 95% CI: 1.37–2.55). However, sensitivity analysis suggested that influential and Hardy-Weinberg equilibrium (HWE)-violating studies may impact the overall effect estimates.

Conclusions

A meta-analysis showed that PPARγ gene polymorphism may be a protective factor for DKD, whereas the ApoE ε2/ε2, ApoE ε2/ε3, and ApoE ε2/ε4 genotypes are associated with an increased risk of DKD. However, the role of ApoE gene polymorphism in susceptibility to DKD is less certain and requires further evaluation.

Peer Review reports

Background

Diabetic kidney disease (DKD) is one of the most serious microvascular complications of diabetes mellitus [1], with an incidence estimated at 30% in people with type 1 diabetes mellitus (T1D) and 40% in those with type 2 diabetes mellitus (T2D) [2]. DKD is the largest contributor to the burden of end-stage renal disease (ESRD), being its leading cause and accounting for nearly 50% of cases in developed countries worldwide [3]. The development and progression of DKD are multifactorial, involving genetic and environmental risk factors that induce and propagate a complex series of pathophysiological processes [4]. Previous studies provided insight into the molecular mechanisms and interrelated pathophysiological pathways in the pathogenesis of DKD, and dyslipidemia [5] along with aberrant glucose metabolism [6] emerged as one of the key metabolic dysregulations closely associated with DKD. An essential number of studies were performed to investigate the association of single nucleotide polymorphisms (SNPs) in the PPARγ, ApoE, CETP, LPL, and ACACB genes, implicated in ensuring metabolic homeostasis, with susceptibility to DKD; however, the findings are still contradictory and require further exploration.

Peroxisome proliferator-activated receptor γ (PPARγ) is involved in the regulation of lipid and glucose metabolism and inflammatory pathways by orchestrating the expression of a network of genes [7]. Most especially, PPARγ is a key transcription factor that governs adipogenesis [7], adipocyte differentiation, fatty acid storage, and is regarded as an encouraging target for antidiabetic therapy [8]. Several gene polymorphisms in the PPARγ gene were reported to be associated with metabolic dysregulation, including insulin resistance, obesity, and T2D [9,10,11]. The PPARγ rs1801282 C > G polymorphism (also known as Pro12Ala), located in exon B, is the most extensively studied SNP, resulting in a proline to alanine alteration at amino acid residue 12 of the PPARγ2 isoform [12], which impairs PPARγ2 transactivation capacity in vitro [13, 14]. Some studies suggested that the Pro12Ala polymorphism is associated with a reduced risk of DKD in patients with T2D [15,16,17,18,19,20,21]; however, some other studies found no evidence of a significant association, leaving uncertainty about its role in DKD [22,23,24,25].

Apolipoprotein E (ApoE) plays a senior role in cholesterol homeostasis and lipid metabolism [26]. The three major ApoE alleles (ε2, ε3, and ε4) are determined by two SNPs on exon 4 of the ApoE gene (rs429358; rs7412) [26, 27]. The ε3 allele is the most predominant in the majority of the population and is considered “wild-type” [28] with an allele frequency of approximately 77.8%, while the allele distribution for ε2 and ε4 accounts for 7.7% and 14.5%, respectively [29]. The various combinations of ApoE alleles yield six genotypes (ε2/ε2, ε2/ε3, ε2/ε4, ε3/ε3, ε3/ε4, and ε4/ε4). The three main isoforms, ApoE2, ApoE3, and ApoE4, encoded by three corresponding alleles (ε2, ε3, and ε4), differ in their lipid-binding ability and affinity for low-density lipoprotein receptors (LDLR) [30]. Although many studies focused on the genetic association of ApoE gene polymorphism with susceptibility to DKD in various populations, including Europeans and Asians, they failed to reach a unified conclusion.

Cholesteryl ester transfer protein (CETP) is involved in the reverse cholesterol transport pathway [31]. A common TaqIB variant in the CETP gene was found to be associated with reduced CETP activity and a subpopulation of high-density lipoproteins (HDLs) with atheroprotective properties [32]. There is a growing number of genetic association studies examining the relationship between CETP gene variants and diabetic microvascular complications, including DKD, but results remain inconsistent and controversial [33,34,35,36].

Lipoprotein lipase (LPL) is essential for lipid metabolism, primarily by promoting intravascular lipolysis of triglyceride (TG)-rich lipoproteins [37]. Impaired LPL activity is characterized by the development of hypertriglyceridemia caused by the accumulation of chylomicrons and very low-density lipoproteins (VLDLs) in plasma [37]. Several studies have demonstrated associations between polymorphisms in the LPL gene and T2D-related complications [38,39,40,41]. We hypothesized that there may be a potential association between SNPs in the LPL gene and DKD that needs to be explored through a quantitative research synthesis.

Acetyl coenzyme A carboxylase beta (ACACB) is implicated in the regulation of fatty acid oxidation [42]. Accelerated fatty acid synthesis and decreased fatty acid oxidation were found to lead to the accumulation of fatty acids that was observed in diabetic kidneys [43]. The role of ACACB polymorphism in the development of DKD remains controversial due to conflicting findings from various studies.

We aimed to conduct an updated meta-analysis to further comprehensively synthesize and quantitatively investigate the association of PPARγ, ApoE, CETP, LPL, and ACACB gene polymorphisms with the risk of DKD by including recently published articles.

Methods

We conducted this meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines [44] and the published PROSPERO research protocol (CRD42024554244).

Search strategy

Four English electronic bibliographic databases, including MEDLINE Complete, Web of Science, Embase, and PubMed, were searched to retrieve potentially relevant studies that examined the association of PPARγ, ApoE, CETP, LPL, and ACACB gene polymorphisms with susceptibility to DKD. The comprehensive search strategies included various combinations of medical subject heading (MeSH) terms and keywords. Search queries were tailored for each database based on its specific features. Full database search strategies are detailed in Supplementary Method S1. In addition to electronic database searches, previously published meta-analyses and reference lists of included studies and relevant review articles were screened to identify other potentially eligible scientific works. The search strategy included searching for English-language studies published in the period with no start date limit until May 2024. The retrieved publications were grouped and processed using Zotero reference management software (version 6.0.37).

Selection criteria

The inclusion criteria were as follows: (1) studies that included patients diagnosed with DKD as cases and diabetic individuals without DKD as controls; (2) studies evaluating the association between PPARγ, ApoE, CETP, LPL and ACACB gene polymorphisms and susceptibility to DKD; (3) studies providing sufficient information, including genotype frequency, to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs); and (4) full-text articles with adult research participants over 18 years of age.

Studies meeting any of the following exclusion criteria were considered ineligible: (1) non-original works, including reviews and meeting abstracts; (2) using an unvalidated genotyping method; (3) insufficient data to calculate the OR with 95% CI; (4) the study participants were adolescents (under 18 years of age) and children; and (5) animal studies.

Data extraction

Data were extracted by two researchers independently (B.T. and K.M.). All disagreements were resolved by discussion to reach a final consensus. If consensus was not obtained, any inconsistency was solved by a third (senior) reviewer. The information extracted from each eligible study was as follows: first author’s name, year of publication, ethnicity/geographic region, definition of case and control groups, number, mean age and gender distribution of cases and controls, diabetes-related issues (type and duration of diabetes), rs number (rsID), genotyping method, genotype frequencies in case and control groups, OR (95% CI), and evidence of Hardy-Weinberg equilibrium (HWE) in control group (in a group of healthy people or diabetic individuals without DKD in the absence of the former).

Statistical analysis

STATA software (versions Stata/MP17.0 and Stata/MP18.0) was used for data analysis, management, and reporting. The association between gene polymorphisms and susceptibility to DKD was determined by estimating pooled ORs and 95% CIs. Analysis of the relationship between gene polymorphism in the PPARG gene and the risk of DKD was conducted under a dominant genetic model (Ala/Ala + Ala/Pro vs. Pro/Pro). Genotype-based case-control comparison was used to calculate the overall estimated effect size of the ApoE gene variant on the risk of DKD. Heterogeneity and inconsistency were measured using the Chi-square test (Cochrane Q statistic) and inconsistency index (I2) test. Summarized ORs were calculated using the random-effects model (REM) with DerSimonian-Laird estimate of tau2 when evidence of significant heterogeneity was present. Otherwise, a fixed-effects model (FEM) was applied. Subgroup analysis was performed to explore potential sources of heterogeneity. The chi-squared test was used to analyze whether the genotype distribution in the control group corresponded to HWE. In case of impossibility of calculation due to lack of data, we relied on the specified data in the publication. The stability of the meta-analysis results was validated by several sensitivity analysis techniques: (1) examining the impact of each study on the overall effect size estimate and identifying influential studies using a leave-one-out test; (2) recalculation after excluding HWE-violating studies; (3) replacing one statistical model with another (REM to FEM and vice versa). Publication bias was assessed using Begg’s rank test, Egger’s regression test, and Begg’s funnel plot. Methodological quality assessment of each eligible study considered for the present meta-analysis was performed independently by two investigators (B.T. and Z.S.) using the Newcastle-Ottawa Scale (NOS) [45]. NOS is scored by assigning a maximum of nine points for case-control and cohort studies and seven for cross-sectional studies. Conflicting opinions were resolved by a third (senior) reviewer. Case-control and cohort studies scoring 0–3, 4–6, and 7–9 were considered low, moderate, and high quality, respectively. For cross-sectional studies, we set the cut-off level ≥ 4, which indicates good and high-quality studies. All articles assessed for methodological quality were rated as good to high quality. Two prospective observational follow-up studies were not critically appraised because we extracted baseline data before the follow-up period.

Results

Characteristics of included studies

Figure 1 presents the detailed steps of our literature search. In the first stage of the search, 702 potentially relevant articles were retrieved from electronic databases. After excluding duplicates, 321 articles remained. Following title and abstract screening, 228 studies were considered irrelevant. The remaining 94 studies, including one that was identified through a review of the reference lists of retrieved publications, were subject to full-text evaluation for eligibility. After full-text screening, 56 articles were removed for various reasons indicated in Fig. 1. No studies were found examining the same gene variants in the CETP and LPL genes. Regarding ACACB gene polymorphisms, we identified no new studies, and the search coincides with the results of previous meta-analyses [46, 47]. In addition, no unexplored genetic variations at ApoE and PPARγ in T1D were published. Therefore, our meta-analysis was focused on the study of genetic polymorphisms in the ApoE and PPARγ in patients with type 2 diabetes. A total of 18 studies concerning the relationship between PPARγ Pro12Ala gene polymorphism and risk of DKD, with 3467 DKD cases and 5676 diabetic controls, met the inclusion criteria and were included in the meta-analysis. Overall, 20 publications on ApoE gene polymorphism and susceptibility to DKD with 3054 DKD participants and 4216 diabetic participants without DKD were added to the meta-analysis. The main characteristics of the selected studies are listed in Supplementary Tables S1 - S4. PRISMA flow diagrams presenting the results of the literature search and study selection process for each genetic polymorphism separately are provided in Supplementary Figures S4 - S8.

Fig. 1
figure 1

PRISMA flow diagram presenting the results of the literature search and study selection process

Association of PPARγ Pro12Ala gene polymorphism with DKD susceptibility in T2D

Figure 2A demonstrates the pooled results of the association of the PPARγ Pro12Ala polymorphism with DKD risk under a dominant genetic model (Ala carriers vs. Pro homozygotes (Pro/Pro)). Overall, the PPARγ Pro12Ala polymorphism was significantly associated with a reduced risk of DKD (OR = 0.74, 95% CI: 0.62–0.88, Ph = 0.1; I2 = 30.4%) under REM.

Subgroup analysis stratified by ethnic group revealed a significant association between the PPARγ Pro12Ala gene polymorphism and susceptibility to DKD in both Asian (OR = 0.73; 95% CI: 0.56–0.95; Ph = 0.19; I2 = 29%) and Caucasian populations (OR = 0.74; 95% CI: 0.59–0.93; Ph = 0.2; I2 = 27.9%) (Table 1).

Table 1 Subgroup analysis of the association between PPARγ Pro12Ala polymorphism and DKD risk in T2D

Furthermore, in subgroup analysis based on albuminuria category, Ala carriers presented a decreased risk of both microalbuminuria and macroalbuminuria with corresponding ORs of 0.58 (95% CI: 0.43–0.78; Ph = 0.41; I2 = 2%) and 0.68 (95% CI: 0.53–0.86; Ph = 0.44; I2 = 0%) compared with Pro homozygotes (Table 1).

Fig. 2
figure 2

Forest plot for association between PPARγ and ApoE gene polymorphisms and DKD risk in T2D

Note. A PPARγ (Ala carriers vs. Pro homozygotes (Pro/Pro))*; B ApoE (ε3/ε4 vs. ε3/ε3)*; C ApoE (ε4/ε4 vs. ε3/ε3)*; D ApoE (ε2/ε2 vs. ε3/ε3); E ApoE (ε2/ε3 vs. ε3/ε3)*; F ApoE (ε2/ε4 vs. ε3/ε3)*; * Random-effects model was applied

Association of ApoE gene polymorphism with DKD susceptibility in T2D

When compared with the APOE ε3/ε3, the pooled OR for the association between APOE ε2/ε2 and DKD was 1.93 (95% CI: 1.03–3.61; Ph = 0.89; I2 = 0%) (Fig. 2D). The ApoE ε2/ε3 significantly increased the risk of DKD (OR = 1.63; 95% CI: 1.19–2.25; Ph < 0.001; I2 = 66.5%) in a comparison with the APOE ε3/ε3 genotype (Fig. 2E). Similarly, the ApoE ε2/ε4 genotype exhibited the same trend, increasing the risk of DKD with an OR of 1.87 (95% CI: 1.37–2.55; Ph = 0.43; I2 = 2%) as compared to the APOE ε3/ε3 genotype (Fig. 2F). ApoE ε3/ε4 and ε4/ε4 genotypes demonstrated a statistically insignificant effect on susceptibility to DKD compared with the ε3/ε3 genotype (ε3/ε4 vs. ε3/ε3: OR = 0.86, 95% CI: 0.69–1.07, Ph = 0.007; I2 = 50.3%; ε4/ε4 vs. ε3/ε3: OR = 0.95, 95% CI: 0.61–1.50, Ph = 0.36; I2 = 8.5%) (Fig. 2B, C).

Table 2 presents the results of the subgroup analysis. Subgroup analysis by ethnicity showed a significant association between ApoE ε2/ε2, ε2/ε3 genotypes and an increased risk of DKD in the East Asian population (ε2/ε2 vs. ε3/ε3: OR = 1.99, 95% CI: 1.04–3.82, Ph = 0.92; I2 = 0%; ε2/ε3 vs. ε3/ε3: OR = 1.81, 95% CI: 1.36–2.42, Ph = 0.04; I2 = 46.9%), whereas no association was observed in other populations.

Table 2 Subgroup analysis of the association between ApoE genotypes and DKD risk in T2D by ethnicity

In a subgroup analysis based on albuminuria category, ApoE ε2/ε4 significantly increased the risk of microalbuminuria compared with ε3/ε3 genotype (OR = 3.32; 95% CI: 1.13–9.73, Ph = 0.66; I2 = 0%). However, a comparison of ApoE ε3/ε4 with the ε3/ε3 genotype revealed a lower incidence of microalbuminuria with an OR of 0.66 (95% CI: 0.44–0.99, Ph = 0.56; I2 = 0%). This meta-analysis did not find a statistically significant effect of ApoE ε4/ε4, ε2/ε2, and ε2/ε3 genotypes on the risk of either microalbuminuria or macroalbuminuria (Table 3).

Table 3 Subgroup analysis of the association between ApoE genotypes and DKD risk in T2D by albuminuria

Sensitivity analysis

Tables 4 and 5 show the results of the leave-one-out sensitivity analysis for PPARγ and ApoE, respectively. Regarding PPARγ, the sensitivity method did not identify any individual articles influencing the combined ORs and 95% CIs. In an analysis comparing ApoE ε2/ε2 with the ε3/ε3 genotype, after omitting studies by Gan et al. (2023) [48], Jiang et al. (2017) [49], Atta et al. (2016) [50], Akarsu et al. (2001) [51], and Horita et al. (1994) [52] the overall results did not remain stable and became statistically insignificant, showing that these studies had the highest influence on the pooled estimate. Additionally, the greatest impact of the individual study by Atageldiyeva et al. (2019) [53] on the overall OR was revealed when comparing ApoE ε2/ε4 with the ε3/ε3 genotype. The exclusion of this study rendered the summarized result statistically insignificant. Replacing one statistical model with another (REM with FEM and vice versa) did not lead to statistically significant changes in the combined ORs in both ApoE and PPARγ analyses, which indicates the stability of the overall effect estimates (Supplementary Figure S2). In addition, in the PPARγ analysis, excluding studies with a genotype frequency in controls deviating from the HWE did not result in statistically significant alterations in the summarized results, indicating the robustness of the meta-analysis results (Supplementary Figure S3). However, when comparing ApoE ε2/ε2, ApoE ε2/ε3, and ApoE ε2/ε4 with the ε3/ε3 genotype, the overall estimates became nonsignificant after removing studies with genotype frequency in controls not following HWE (Supplementary Figure S3).

Table 4 Leave-one-out sensitivity analysis of the association between PPARγ Pro12Ala polymorphism and DKD risk
Table 5 Leave-one-out sensitivity analysis of the association between ApoE genotypes and DKD risk

Evaluation of publication bias

Begg’s funnel plot, Begg’s rank test, and Egger’s regression test revealed no evidence of publication bias in the overall (PEgger = 0.12; PBegg = 0.1; Begg’s funnel plot is shown in Supplementary Figure S1) and subgroup analyses of the relationship between the PPARγ Pro12Ala gene polymorphism and the risk of DKD, with the exception of the subgroup analysis involving the Caucasian population (Table 1). No publication bias was found in the overall (Supplementary Figure S1) or subgroup analyses between any ApoE genotype and DKD risk (Tables 2 and 3), except for the analysis comparing ApoE ε3/ε4 with the ε3/ε3 genotype (PEgger = 0.01; PBegg = 0.11; Begg’s funnel plot is shown in Supplementary Figure S1) and the subgroup analysis evaluating the association between ApoE ε2/ε4 and susceptibility to microalbuminuria (Table 3).

Discussion

This meta-analysis made a significant contribution to further investigation of the relationship between polymorphisms in the ApoE and PPARγ genes and susceptibility to DKD, including the integration of data from recently published articles into a quantitative synthesis. A missense Pro12Ala substitution in the PPARγ gene demonstrated a protective effect against DKD, indicating that Ala carriers are less likely to develop DKD than wild-type Pro homozygotes. The ApoE ε2/ε2, ApoE ε2/ε3, and ApoE ε2/ε4 genotypes were shown to be associated with an increased risk of DKD.

Many studies reported the potential association of the PPARγ Pro12Ala gene polymorphism and the risk of T2D [12, 76,77,78], which generated scientific interest in the presumable role of the gene variant in susceptibility to diabetic complications. The predominant explanation for the association between PPARγ Pro12Ala polymorphism and DKD risk converges on the effect of genetic variation in attenuating insulin resistance [13] and oxidative stress [79, 80] as one of the major determinants of the development and progression of DKD [81, 82]. There are a growing number of genetic association studies examining the influence of the PPARγ Pro12Ala polymorphism on susceptibility to DKD, but results remain inconsistent and contradictory. Our present meta-analysis results are in agreement with the findings from De Cosmo et al. (2011) [56], Zhang et al. (2012) [17], Wang et al. (2013) [83], Li et al. (2015) [46], and Ding et al. (2015) [84], which reported that the Pro12Ala variant was significantly associated with a reduced risk of DKD in T2D. In a subgroup analysis, we further identified a trend towards a lower incidence of DKD in Ala carriers in Asian and Caucasian populations. To our knowledge, this is the first meta-analysis whose results demonstrated statistically significant associations between PPARγ Pro12Ala polymorphism and DKD in Asians. The difference in findings regarding the Asian population could speculatively be due to the favorable lower between-study heterogeneity in our meta-analysis, which was not observed in previous studies (I2 = 42.9–54.7%). However, our analysis among Asians still showed moderate between-study heterogeneity, which may influence the interpretation of the findings. Further, based on albuminuria category, subgroup analysis revealed that Ala carriers showed a reduced risk of both microalbuminuria and macroalbuminuria than Pro homozygotes. The same conclusion was reached in the studies by Zhang et al. (2012) [17] and Li et al. (2015) [46]. The stability of the meta-analysis results was validated using several sensitivity analysis techniques. None of the methods raised suspicions regarding their stability. Notably, publication bias was found in the subgroup analysis of the association between the PPARγ Pro12Ala polymorphism and the risk of DKD among Caucasians. Publication bias with an imbalance of findings in favor of positive results may produce misleading conclusions. Further research is needed to clarify the influence of the PPARγ Pro12Ala polymorphism on susceptibility to DKD in different ethnic groups.

ApoE is a potent modulator of plasma lipids level, promoting clearance of TG-rich lipoproteins, specifically chylomicrons and VLDLs, from circulation [85]. The latter is mediated by the binding of ApoE on the lipolyzed lipoprotein particles to the LDLR, LDLR-related protein, and heparan sulfate proteoglycans (HSPG) located on the surface of hepatocytes where the remnant particles are endocytosed and eliminated from the bloodstream [30]. The parent form, ApoE3, is characterized by optimal receptor-binding capacity and normal lipoprotein metabolism, while the ApoE2 and ApoE4 isoforms exhibit altered functionalities and are associated with dyslipidemia [30]. A large body of evidence suggests that dyslipidemia has a senior role in the development and progression of DKD [86], causing kidney injury through stimulation of transforming growth factor beta (TGF-β), production of reactive oxygen species and thereby inducing glomeruli and glomerular glycocalyx damage [87]. Moreover, clinicopathological data showed that ε2 carriers had a more pronounced glomerulopathy characterized by glomerular hypertrophy as well as increased expression of ApoE protein in nodular lesions [88]. Numerous studies investigated the effects of the ApoE gene polymorphism on DKD, but the results are contradictory and inconclusive. The lack of concordance across these studies reflected limitations, including insufficient sample sizes, ethnic background differences, variation in diabetes duration in control groups (the shorter the duration, the greater the likelihood of misclassifying potential cases of DKD due to a delayed phenotype), various DKD phenotype definition and research methodology. Our main analysis demonstrated a significant association between ApoE ε2/ε2, ApoE ε2/ε3, and ApoE ε2/ε4 genotypes and an increased risk of DKD. The present findings are compliant with previously published studies performed by Feng et al. (2010) [89], Li et al. (2011) [90], and Shi et al. (2020) [91]. Most especially, Shi et al. (2020) [91] recently reported that all ApoE ε2-involved genotypes (ε2/ε2, ε2/ε3, and ε2/ε4) conferred a higher risk of developing DKD. In subgroup analysis, ApoE ε2/ε2 and ε2/ε3 genotypes were associated with greater susceptibility to DKD in the East Asian subgroup, which was also observed in the results of studies by Feng et al. (2010) [89], Li et al. (2011) [90] and Li et al. (2015) [46]. We found no statistically significant association between the ApoE variant and DKD in other populations, consistent with previous meta-analyses [46, 90], possibly due to racial differences in ApoE allele frequencies [92]. However, the moderate and high between-study heterogeneity should also be considered when interpreting the results. We further identified a trend towards a higher incidence of microalbuminuria in individuals with ApoE ε2/ε4 genotype. The subanalysis yielded positive results for the association of the ApoE ε3/ε4 genotype with a reduced risk of microalbuminuria. Notably, the sensitivity analysis identified influential studies with a significant contribution to the overall effect estimate when analyzing the relationship between both ApoE ε2/ε2 and ApoE ε2/ε4 genotypes with DKD. Furthermore, sensitivity analysis results suggested that removing HWE-violating studies may impact the combined results when comparing all ApoE ε2-involved genotypes. Therefore, additional studies of high methodological quality are required to accurately determine the associations of ApoE ε2-involved genotypes with the risk of DKD. We detected no publication bias in the overall or subgroup analyses between any ApoE genotype and DKD risk, except for the analysis comparing the ApoE ε3/ε4 with the ε3/ε3 genotype and the subgroup analysis evaluating the association between ApoE ε2/ε4 and susceptibility to microalbuminuria.

Our meta-analysis with a rigorous methodology, including comprehensive literature searches, careful data extraction, and appropriate statistical techniques demonstrated two important issues. The first is related to publication bias, which can distort the evidence base, resulting in misleading estimates of effect sizes and influencing clinical and policy decisions based on incomplete evidence. Addressing publication bias involves increasing transparency and encouraging the publication of all research results. The second issue concerns the empirical evaluation of genetic association studies. Deviation from HWE may challenge the validity of studies, requiring a revision of the study methodology, sampling strategies, and genotyping procedures [93,94,95]. Excluding studies that do not follow HWE when conducting sensitivity analysis can improve the accuracy, credibility, and reliability of the results. By focusing on studies with genotype frequencies that comply with HWE proportions, researchers may provide more precise and trustworthy estimates of effect sizes or associations. An unbiased conclusion is crucial for making informed decisions in clinical practice, policy-making, and further research.

Our meta-analysis has certain limitations that should be considered when interpreting its results. First, focusing only on publications written in English makes the results vulnerable to retrieval of non-English-language research findings among other ethnic populations. Second, the observed significant heterogeneity in the results of ApoE polymorphism analyses could potentially mask or exaggerate true associations. Further, the identified publication bias in the included studies analyzing the association of the PPARγ variant with the risk of DKD in Caucasians, as well as in studies comparing ApoE ε3/ε4 with the ε3/ε3 genotype, and those analyzing the association between ApoE ε2/ε4 and susceptibility to microalbuminuria, may lead to incorrect conclusions. Finally, a larger sample size is needed to enhance the reliability of result interpretation in subgroup analyses.

Conclusion

In conclusion, based on the meta-analysis, we suggest that the PPARγ gene polymorphism may have a protective effect against DKD, whereas the ApoE ε2/ε2, ApoE ε2/ε3, and ApoE ε2/ε4 genotypes are associated with an increased risk of DKD. However, the role of ApoE gene polymorphism in susceptibility to DKD is less clear and requires further research. In addition, given the influence of gene-gene and gene-environment interplay on the development of DKD, more studies are required to investigate the interaction of polymorphisms in the PPARγ and ApoE genes with other factors to further elucidate their pathogenetic role. Exploring the association between genetic variations and disease risk has the potential to revolutionize our understanding of disease development, contributing to the identification of underlying biological pathways and providing further steps toward elaborating personalized therapy and preventive strategies.

Data availability

All data supporting the conclusions of this article are included in the article.

Abbreviations

ACACB:

Acetyl coenzyme A carboxylase beta

ApoE:

Apolipoprotein E

CETP:

Cholesteryl ester transfer protein

DKD:

Diabetic kidney disease

ESRD:

End-stage renal disease

FEM:

Fixed-effects model

HSPG:

Heparan sulfate proteoglycans

HWE:

Hardy-Weinberg equilibrium

LDLR:

Low-density lipoprotein receptors

LPL:

Lipoprotein lipase

MeSH:

Medical subject heading

NOS:

Newcastle-Ottawa Scale

PPARγ:

Peroxisome proliferator-activated receptor γ

REM:

Random-effects model

SNP:

Single nucleotide polymorphisms

T1D:

Type 1 diabetes mellitus

T2D:

Type 2 diabetes mellitus

TG:

Triglyceride

VLDL:

Very low-density lipoproteins

References

  1. Samsu N. Diabetic nephropathy: challenges in pathogenesis, diagnosis, and treatment. Biomed Res Int. 2021;2021:1–17. https://doiorg.publicaciones.saludcastillayleon.es/10.1155/2021/1497449.

    Article  CAS  Google Scholar 

  2. Tuttle KR, Agarwal R, Alpers CE, Bakris GL, Brosius FC, Kolkhof P, Uribarri J. Molecular mechanisms and therapeutic targets for diabetic kidney disease. Kidney Int. 2022;102(2):248–60. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.kint.2022.05.012.

    Article  CAS  PubMed  Google Scholar 

  3. Zheng L, Chen X, Luo T, Ran X, Hu J, Cheng Q, Yang S, Wu J, Li Q, Wang Z. Early-onset type 2 diabetes as a risk factor for end-stage renal disease in patients with diabetic kidney disease. Prev Chronic Dis. 2020;17:E50. https://doiorg.publicaciones.saludcastillayleon.es/10.5888/pcd17.200076.

    Article  PubMed  PubMed Central  Google Scholar 

  4. Navarro-González JF, Mora-Fernández C, Muros de Fuentes M, García-Pérez J. Inflammatory molecules and pathways in the pathogenesis of diabetic nephropathy. Nat Rev Nephrol. 2011;7(6):327–40. https://doiorg.publicaciones.saludcastillayleon.es/10.1038/nrneph.2011.51.

    Article  CAS  PubMed  Google Scholar 

  5. Su W, Cao R, He YC, Guan YF, Ruan XZ. Crosstalk of hyperglycemia and dyslipidemia in diabetic kidney disease. Kidney Dis (Basel). 2017;3(4):171–80. https://doiorg.publicaciones.saludcastillayleon.es/10.1159/000479874.

    Article  PubMed  Google Scholar 

  6. Agarwal R. Pathogenesis of diabetic nephropathy. ADA Clin Compendia. 2021;2021(1):2–7. https://doiorg.publicaciones.saludcastillayleon.es/10.2337/db20211-2.

    Article  Google Scholar 

  7. Cataldi S, Costa V, Ciccodicola A, Aprile M. PPARγ and diabetes: beyond the genome and towards personalized medicine. Curr Diab Rep. 2021;21(6):18. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s11892-021-01385-5.

    Article  PubMed  Google Scholar 

  8. Shafi S, Khurana N, Gupta J. PPAR gamma agonistic activity of dillapiole: protective effects against diabetic nephropathy. Nat Prod Res. 2024:1–6. https://doiorg.publicaciones.saludcastillayleon.es/10.1080/14786419.2024.2334323

  9. Tiongco RE, Basilio H, Camacho DR, Ellorin WM, Sico CA, Arceo E. Association of the rs3856806 polymorphism in the PPARG gene with type 2 diabetes mellitus: a meta-analysis of 11,811 individuals. Lab Med. 2023;54(2):193–8. https://doiorg.publicaciones.saludcastillayleon.es/10.1093/labmed/lmac095.

    Article  PubMed  Google Scholar 

  10. Kasim NB, Huri HZ, Vethakkan SR, Ibrahim L, Abdullah BM. Genetic polymorphisms associated with overweight and obesity in uncontrolled type 2 diabetes mellitus. Biomark Med. 2016;10(4):403–15. https://doiorg.publicaciones.saludcastillayleon.es/10.2217/bmm-2015-0037.

    Article  CAS  PubMed  Google Scholar 

  11. Mansoori A, Amini M, Kolahdooz F, Seyedrezazadeh E. Obesity and Pro12Ala polymorphism of peroxisome proliferator-activated receptor-gamma gene in healthy adults: a systematic review and meta-analysis. Ann Nutr Metab. 2015;67(2):104–18. https://doiorg.publicaciones.saludcastillayleon.es/10.1159/000439285.

    Article  CAS  PubMed  Google Scholar 

  12. Sarhangi N, Sharifi F, Hashemian L, Hassani Doabsari M, Heshmatzad K, Rahbaran M, Jamaldini SH, Aghaei Meybodi HR, Hasanzad M. PPARG (Pro12Ala) genetic variant and risk of T2DM: a systematic review and meta-analysis. Sci Rep. 2020;10(1):12764. https://doiorg.publicaciones.saludcastillayleon.es/10.1038/s41598-020-69363-7.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  13. Deeb SS, Fajas L, Nemoto M, Pihlajamäki J, Mykkänen L, Kuusisto J, Laakso M, Fujimoto W, Auwerx J. A Pro12Ala substitution in PPARgamma2 associated with decreased receptor activity, lower body mass index and improved insulin sensitivity. Nat Genet. 1998;20(3):284–7. https://doiorg.publicaciones.saludcastillayleon.es/10.1038/3099.

    Article  CAS  PubMed  Google Scholar 

  14. Masugi J, Tamori Y, Mori H, Koike T, Kasuga M. Inhibitory effect of a proline-to-alanine substitution at codon 12 of peroxisome proliferator-activated receptor-gamma 2 on thiazolidinedione-induced adipogenesis. Biochem Biophys Res Commun. 2000;268(1):178–82. https://doiorg.publicaciones.saludcastillayleon.es/10.1006/bbrc.2000.2096.

    Article  CAS  PubMed  Google Scholar 

  15. Chen YN, Wang PW, Tung SC, Kuo MC, Weng SW, Chou CK, Chang CM, Tsa CJ, Taso CF, Shen FC, Chen JF. Association between Pro12Ala polymorphism and albuminuria in type 2 diabetic nephropathy. J Diabetes Investig. 2020;11(4):923–9. https://doiorg.publicaciones.saludcastillayleon.es/10.1111/jdi.13208.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  16. Lapice E, Monticelli A, Cocozza S, Pinelli M, Cocozza S, Bruzzese D, Riccardi G, Vaccaro O. The PPARγ2 Pro12Ala variant is protective against progression of nephropathy in people with type 2 diabetes. J Transl Med. 2015;13:85. https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12967-015-0448-6.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  17. Zhang H, Zhu S, Chen J, Tang Y, Hu H, Mohan V, Venkatesan R, Wang J, Chen H. Peroxisome proliferator-activated receptor γ polymorphism Pro12Ala is associated with nephropathy in type 2 diabetes: evidence from meta-analysis of 18 studies. Diabetes Care. 2012;35(6):1388–93. https://doiorg.publicaciones.saludcastillayleon.es/10.2337/dc11-2142.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. Liu L, Zheng T, Wang F, Wang N, Song Y, Li M, Li L, Jiang J, Zhao W. Pro12Ala polymorphism in the PPARG gene contributes to the development of diabetic nephropathy in Chinese type 2 diabetic patients. Diabetes Care. 2010;33(1):144–9. https://doiorg.publicaciones.saludcastillayleon.es/10.2337/dc09-1258.

    Article  CAS  PubMed  Google Scholar 

  19. De Cosmo S, Motterlini N, Prudente S, Pellegrini F, Trevisan R, Bossi A, Remuzzi G, Trischitta V, Ruggenenti P, BENEDICT Study Group. Impact of the PPAR-gamma2 Pro12Ala polymorphism and ACE inhibitor therapy on new-onset microalbuminuria in type 2 diabetes: evidence from BENEDICT. Diabetes. 2009;58(12):2920–9. https://doiorg.publicaciones.saludcastillayleon.es/10.2337/db09-0407.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  20. Caramori ML, Canani LH, Costa LA, Gross JL. The human peroxisome proliferator-activated receptor gamma2 (PPARgamma2) Pro12Ala polymorphism is associated with decreased risk of diabetic nephropathy in patients with type 2 diabetes. Diabetes. 2003;52(12):3010–3. https://doiorg.publicaciones.saludcastillayleon.es/10.2337/diabetes.52.12.3010.

    Article  CAS  PubMed  Google Scholar 

  21. Herrmann SM, Ringel J, Wang JG, Staessen JA, Brand E. Peroxisome proliferator-activated receptor-gamma2 polymorphism Pro12Ala is associated with nephropathy in type 2 diabetes: the Berlin Diabetes Mellitus (BeDiaM) Study. Diabetes. 2002;51(8):2653–7. https://doiorg.publicaciones.saludcastillayleon.es/10.2337/diabetes.51.8.2653.

    Article  CAS  PubMed  Google Scholar 

  22. Hashemian L, Sarhangi N, Afshari M, Aghaei Meybodi HR, Hasanzad M. The role of the PPARG (Pro12Ala) common genetic variant on type 2 diabetes mellitus risk. J Diabetes Metab Disord. 2021;20(2):1385–90. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s40200-021-00872-6.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  23. Regine I, Husain RSRA, Aswathi RP, Reddy DR, Ahmed SSSJ, Ramakrishnan V. Association between PPARγrs1801282 polymorphism with diabetic nephropathy and type-2 diabetes mellitus susceptibility in south India and a meta-analysis. Nefrologia. 2020;40(3):287–98. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.nefro.2020.01.005.

    Article  PubMed  Google Scholar 

  24. Liu G, Zhou TB, Jiang Z, Zheng D, Yuan F, Li Y, Hu H, Chen Z. Relationship between PPARγ Pro12Ala gene polymorphism and type 2 diabetic nephropathy risk in Asian population: results from a meta-analysis. J Recept Signal Transduct Res. 2014;34(2):131–6. https://doiorg.publicaciones.saludcastillayleon.es/10.3109/10799893.2013.864678.

    Article  CAS  PubMed  Google Scholar 

  25. Bhaskar LV, Mahin S, Ginila RT, Soundararajan P. Role of the ACE ID and PPARG P12A polymorphisms in genetic susceptibility of diabetic nephropathy in a south Indian population. Nephrourol Mon. 2013;5(3):813–7. https://doiorg.publicaciones.saludcastillayleon.es/10.5812/numonthly.9573.

    Article  PubMed  PubMed Central  Google Scholar 

  26. Lumsden AL, Mulugeta A, Zhou A, Hyppönen E. Apolipoprotein E (APOE) genotype-associated disease risks: a phenome-wide, registry-based, case-control study utilising the UK Biobank. EBioMedicine. 2020;59:102954. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.ebiom.2020.102954.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  27. Seripa D, D’Onofrio G, Panza F, Cascavilla L, Masullo C, Pilotto A. The genetics of the human APOE polymorphism. Rejuvenation Res. 2011;14(5):491–500. https://doiorg.publicaciones.saludcastillayleon.es/10.1089/rej.2011.1169.

    Article  CAS  PubMed  Google Scholar 

  28. Wolters FJ, Yang Q, Biggs ML, Jakobsdottir J, Li S, Evans DS, et al. The impact of APOE genotype on survival: results of 38,537 participants from six population-based cohorts (E2-CHARGE). PLoS ONE. 2019;14(7):e0219668. https://doiorg.publicaciones.saludcastillayleon.es/10.1371/journal.pone.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  29. Ghebranious N, Ivacic L, Mallum J, Dokken C. Detection of ApoE E2, E3 and E4 alleles using MALDI-TOF mass spectrometry and the homogeneous mass-extend technology. Nucleic Acids Res. 2005;33(17):e149. https://doiorg.publicaciones.saludcastillayleon.es/10.1093/nar/gni155.

    Article  PubMed  PubMed Central  Google Scholar 

  30. Phillips MC. Apolipoprotein E isoforms and lipoprotein metabolism. IUBMB Life. 2014;66(9):616 – 23. https://doiorg.publicaciones.saludcastillayleon.es/10.1002/iub.1314. PMID: 25328986.

  31. Xue H, Zhang M, Liu J, Wang J, Ren G. Structure-based mechanism and inhibition of cholesteryl ester transfer protein. Curr Atheroscler Rep. 2023;25(4):155–66. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s11883-023-01087-1.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  32. Russo GT, Horvath KV, Di Benedetto A, Giandalia A, Cucinotta D, Asztalos B. Influence of menopause and cholesteryl ester transfer protein (CETP) TaqIB polymorphism on lipid profile and HDL subpopulations distribution in women with and without type 2 diabetes. Atherosclerosis. 2010;210(1):294–301. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.atherosclerosis.2009.11.011.

    Article  CAS  PubMed  Google Scholar 

  33. Huang YC, Chen SY, Liu SP, Lin JM, Lin HJ, Lei YJ, Chung YC, Chen YC, Wang YH, Liao WL, Tsai FJ. Cholesteryl Ester transfer protein genetic variants associated with risk for type 2 diabetes and diabetic kidney disease in Taiwanese population. Genes (Basel). 2019;10(10):782. https://doiorg.publicaciones.saludcastillayleon.es/10.3390/genes10100782.

    Article  CAS  PubMed  Google Scholar 

  34. Russo GT, Giandalia A, Romeo EL, Muscianisi M, Ruffo MC, Alibrandi A, Bitto A, Forte F, Grillone A, Asztalos B, Cucinotta D. HDL subclasses and the common CETP TaqIB variant predict the incidence of microangiopatic complications in type 2 diabetic women: a 9years follow-up study. Diabetes Res Clin Pract. 2017;132:108–17. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.diabres.2017.07.026.

    Article  CAS  PubMed  Google Scholar 

  35. McKay GJ, Savage DA, Patterson CC, Lewis G, McKnight AJ, Maxwell AP. Association analysis of dyslipidemia-related genes in diabetic nephropathy. PLoS ONE. 2013;8(3):e58472. https://doiorg.publicaciones.saludcastillayleon.es/10.1371/journal.pone.0058472.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  36. Hadjadj S, Gallois Y, Simard G, Bouhanick B, Passa P, Grimaldi A, Drouin P, Tichet J, Marre M. Lack of relationship in long-term type 1 diabetic patients between diabetic nephropathy and polymorphisms in apolipoprotein epsilon, lipoprotein lipase and cholesteryl ester transfer protein. Nephrol Dial Transpl. 2000;15(12):1971–6. https://doiorg.publicaciones.saludcastillayleon.es/10.1093/ndt/15.12.1971.

    Article  CAS  Google Scholar 

  37. Kumari A, Kristensen KK, Ploug M, Winther AL. The importance of lipoprotein lipase regulation in atherosclerosis. Biomedicines. 2021;9(7):782. https://doiorg.publicaciones.saludcastillayleon.es/10.3390/biomedicines9070782.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  38. Ukkola O, Savolainen MJ, Salmela PI, von Dickhoff K, Kesaniemi YA. DNA polymorphisms at the lipoprotein lipase gene are associated with macroangiopathy in type 2 (non-insulin-dependent) diabetes mellitus. Atherosclerosis. 1995;115:99–105. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/0021-9150(94)05504-c.

    Article  CAS  PubMed  Google Scholar 

  39. Mattu RK, Trevelyan J, Needham EW, Khan M, Adiseshiah MA, Richter D, Murray RG, Betteridge DJ. Lipoprotein lipase gene variants relate to presence and degree of microalbuminuria in type II diabetes. Diabetologia. 2002;45:905–13. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s00125-002-0824-7.

    Article  CAS  PubMed  Google Scholar 

  40. Solini A, Passaro A, Fioretto P, Nannipieri M, Ferrannini E. Lipoprotein lipase gene variants and progression of nephropathy in hypercholesterolaemic patients with type 2 diabetes. J Intern Med. 2004;256:30–6. https://doiorg.publicaciones.saludcastillayleon.es/10.1111/j.1365-2796.2004.01332.x.

    Article  CAS  PubMed  Google Scholar 

  41. Ng MC, Baum L, So WY, Lam VK, Wang Y, Poon E, Tomlinson B, Cheng S, Lindpaintner K, Chan JC. Association of lipoprotein lipase S447X, apolipoprotein E exon 4, and apoC3 -455T > C polymorphisms on the susceptibility to diabetic nephropathy. Clin Genet. 2006;70:20–8. https://doiorg.publicaciones.saludcastillayleon.es/10.1111/j.1399-0004.2006.00628.x.

    Article  CAS  PubMed  Google Scholar 

  42. Riancho JA, Vázquez L, García-Pérez MA, Sainz J, Olmos JM, Hernández JL, Pérez-López J, Amado JA, Zarrabeitia MT, Cano A, Rodríguez-Rey JC. Association of ACACB polymorphisms with obesity and diabetes. Mol Genet Metab. 2011;104(4):670–6. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.ymgme.2011.08.013.

    Article  CAS  PubMed  Google Scholar 

  43. Thongnak L, Pongchaidecha A, Lungkaphin A. Renal lipid metabolism and lipotoxicity in diabetes. Am J Med Sci. 2020;359(2):84–99. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.amjms.2019.11.004.

    Article  PubMed  Google Scholar 

  44. Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:n71. https://doiorg.publicaciones.saludcastillayleon.es/10.1136/bmj.n71.

    Article  PubMed  PubMed Central  Google Scholar 

  45. Wells G, Shea B, O’Connell D, Peterson J et al. May,. The Newcastle-Ottawa Scale (NOS) for assessing the quality of nonrandomised studies in meta-analyses. http://www.ohri.ca/programs/clinical_epidemiology/oxford.asp. Accessed 3 2021.

  46. Li T, Shi Y, Yin J, Qin Q, Wei S, Nie S, Liu L. The association between lipid metabolism gene polymorphisms and nephropathy in type 2 diabetes: a meta-analysis. Int Urol Nephrol. 2015;47(1):117–30. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s11255-014-0843-6.

    Article  CAS  PubMed  Google Scholar 

  47. Tziastoudi M, Stefanidis I, Zintzaras E. The genetic map of diabetic nephropathy: evidence from a systematic review and meta-analysis of genetic association studies. Clin Kidney J. 2020;13(5):768–81. https://doiorg.publicaciones.saludcastillayleon.es/10.1093/ckj/sfaa077.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  48. Gan C, Zhang Y, Zhang X, Huang Q, Guo X. Association of apolipoprotein E gene polymorphism with type 2 diabetic nephropathy in the southern Chinese population. Int J Gen Med. 2023;16:5549–58. https://doiorg.publicaciones.saludcastillayleon.es/10.2147/IJGM.S440103.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  49. Jiang Y, Ma L, Han C, Liu Q, Cong X, Xu Y, Zhao T, Li P, Cao Y. Effects of apolipoprotein E isoforms in diabetic nephropathy of Chinese type 2 diabetic patients. J Diabetes Res. 2017;2017:3560920. https://doiorg.publicaciones.saludcastillayleon.es/10.1155/2017/3560920.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  50. Atta MI, Abo Gabal K, El-Hadidi K, Swellam M, Genina A, Zaher NF. Apolipoprotein E genotyping in Egyptian diabetic nephropathy patients. IUBMB Life. 2016;68(1):58–64. https://doiorg.publicaciones.saludcastillayleon.es/10.1002/iub.1460.

    Article  CAS  PubMed  Google Scholar 

  51. Akarsu E, Pirim I, Capoglu I, Kaya H, Alcay G, Unuvar N. A relation between the apolipoprotein E genotypes and microalbuminuria in type 2 diabetes mellitus. Turk J Med Sci. 2001;31(1):59–64.

    CAS  Google Scholar 

  52. Horita K, Eto M, Makino I. Apolipoprotein E2, renal failure and lipid abnormalities in non-insulin-dependent diabetes mellitus. Atherosclerosis. 1994;107(2):203–11. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/0021-9150(94)90021-3.

    Article  CAS  PubMed  Google Scholar 

  53. Atageldiyeva KK, Nemr R, Echtay A, Racoubian E, Sarray S, Almawi WY. Apolipoprotein E genetic polymorphism influence the susceptibility to nephropathy in type 2 diabetes patients. Gene. 2019;715:144011. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.gene.2019.144011.

    Article  CAS  PubMed  Google Scholar 

  54. Mohamed SH, Allam HM, Kamel AA, Hussein MHS. Association of PPARγ gene polymorphism in Type-2 diabetes Mellitus and its relation to Diabetic kidney disease. NeuroQuantology. 2022;20(10):5517–30. https://doiorg.publicaciones.saludcastillayleon.es/10.14704/nq.2022.20.10.NQ55531.

    Article  Google Scholar 

  55. Ahmed AI, Osman NA, NasrAllah MM, Kamal MM. The association between diabetic nephropathy and polymorphisms in PPARγ pro 12Ala and CCR5δ 32 genes in type 2 diabetes. Egypt J Intern Med. 2013;25(1):10–4. https://doiorg.publicaciones.saludcastillayleon.es/10.7123/01.EJIM.0000425954.57680.ee.

    Article  Google Scholar 

  56. De Cosmo S, Prudente S, Lamacchia O, Lapice E, Morini E, Di Paola R, Copetti M, Ruggenenti P, Remuzzi G, Vaccaro O, Cignarelli M, Trischitta V. PPARγ2 P12A polymorphism and albuminuria in patients with type 2 diabetes: a meta-analysis of case-control studies. Nephrol Dial Transpl. 2011;26(12):4011–6. https://doiorg.publicaciones.saludcastillayleon.es/10.1093/ndt/gfr187.

    Article  CAS  Google Scholar 

  57. Wu LS, Hsieh CH, Pei D, Hung YJ, Kuo SW, Lin E. Association and interaction analyses of genetic variants in ADIPOQ, ENPP1, GHSR, PPARgamma and TCF7L2 genes for diabetic nephropathy in a Taiwanese population with type 2 diabetes. Nephrol Dial Transpl. 2009;24(11):3360–6. https://doiorg.publicaciones.saludcastillayleon.es/10.1093/ndt/gfp271.

    Article  CAS  Google Scholar 

  58. Erdogan M, Karadeniz M, Eroglu Z, Tezcanli B, Selvi N, Yilmaz C. The relationship of the peroxisome proliferator-activated receptor-gamma 2 exon 2 and exon 6 gene polymorphism in Turkish type 2 diabetic patients with and without nephropathy. Diabetes Res Clin Pract. 2007;78(3):355–9. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.diabres.2007.06.005.

    Article  CAS  PubMed  Google Scholar 

  59. Pollex RL, Mamakeesick M, Zinman B, Harris SB, Hegele RA, Hanley AJ. Peroxisome proliferator-activated receptor gamma polymorphism Pro12Ala is associated with nephropathy in type 2 diabetes. J Diabetes Complications. 2007;21(3):166–71. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.jdiacomp.2006.02.006.

    Article  PubMed  Google Scholar 

  60. Stefanski A, Majkowska L, Ciechanowicz A, Frankow M, Safranow K, Parczewski M, Pilarska K. Lack of association between the Pro12Ala polymorphism in PPAR-gamma2 gene and body weight changes, insulin resistance and chronic diabetic complications in obese patients with type 2 diabetes. Arch Med Res. 2006;37(6):736–43. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.arcmed.2006.01.009.

    Article  CAS  PubMed  Google Scholar 

  61. Mori H, Ikegami H, Kawaguchi Y, Seino S, Yokoi N, Takeda J, et al. The Pro12 -->Ala substitution in PPAR-gamma is associated with resistance to development of diabetes in the general population: possible involvement in impairment of insulin secretion in individuals with type 2 diabetes. Diabetes. 2001;50(4):891–4. https://doiorg.publicaciones.saludcastillayleon.es/10.2337/diabetes.50.4.891.

    Article  CAS  PubMed  Google Scholar 

  62. Karimoei M, Pasalar P, Mehrabzadeh M, Daneshpour M, Shojaee M, Forouzanfar K, Razi F. Association between apolipoprotein E polymorphism and nephropathy in Iranian diabetic patients. Saudi J Kidney Dis Transpl. 2017;28(5):997–1002. https://doiorg.publicaciones.saludcastillayleon.es/10.4103/1319-2442.215137.

    Article  PubMed  Google Scholar 

  63. Reis KA, Ebinç FA, Koç E, Demirci H, Erten Y, Güz G, Derici UB, Bali M, Söylemezoğlu O, Arınsoy T, Sindel S. Association of the angiotensinogen M235T and APO E gene polymorphisms in Turkish type 2 diabetic patients with and without nephropathy. Ren Fail. 2011;33(5):469–74. https://doiorg.publicaciones.saludcastillayleon.es/10.3109/0886022X.2011.568133.

    Article  CAS  PubMed  Google Scholar 

  64. Tien KJ, Tu ST, Chou CW, Yang CY, Hsiao JY, Shin SJ, Chen HC, Hsieh MC. Apolipoprotein E polymorphism and the progression of diabetic nephropathy in type 2 diabetes. Am J Nephrol. 2011;33(3):231–8. https://doiorg.publicaciones.saludcastillayleon.es/10.1159/000324561.

    Article  CAS  PubMed  Google Scholar 

  65. Erdogan M, Eroglu Z, Biray C, Karadeniz M, Cetinkalp S, Kosova B, Gunduz C, Topcuoglu N, Ozgen G, Yilmaz C. The relationship of the apolipoprotein E gene polymorphism Turkish type 2 diabetic patients with and without nephropathy. J Endocrinol Invest. 2009;32(3):219–22. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/BF03346455.

    Article  CAS  PubMed  Google Scholar 

  66. Ma SW, Benzie IF, Yeung VT. Type 2 diabetes mellitus and its renal complications in relation to apolipoprotein E gene polymorphism. Transl Res. 2008;152(3):134–42. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.trsl.2008.07.003.

    Article  CAS  PubMed  Google Scholar 

  67. Ilhan N, Kahraman N, Seçkin D, Ilhan N, Colak R. Apo E gene polymorphism on development of diabetic nephropathy. Cell Biochem Funct. 2007;25(5):527–32. https://doiorg.publicaciones.saludcastillayleon.es/10.1002/cbf.1348.

    Article  CAS  PubMed  Google Scholar 

  68. Kwon MK, Rhee SY, Chon S, Oh S, Woo JT, Kim SW, Kim JW, Kim YS, Jeong KH, Lee SH, Lee TW, Ihm CG. Association between apolipoprotein E genetic polymorphism and the development of diabetic nephropathy in type 2 diabetic patients. Diabetes Res Clin Pract. 2007;77(3):S228–32. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.diabres.2007.03.009.

    Article  CAS  PubMed  Google Scholar 

  69. Leiva E, Mujica V, Elematore I, Orrego R, Díaz G, Prieto M, Arredondo M. Relationship between apolipoprotein E polymorphism and nephropathy in type-2 diabetic patients. Diabetes Res Clin Pract. 2007;78(2):196–201. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.diabres.2007.03.018.

    Article  CAS  PubMed  Google Scholar 

  70. Ng MC, Baum L, So WY, Lam VK, Wang Y, Poon E, Tomlinson B, Cheng S, Lindpaintner K, Chan JC. Association of lipoprotein lipase S447X, apolipoprotein E exon 4, and apoC3 -455T > C polymorphisms on the susceptibility to diabetic nephropathy. Clin Genet. 2006;70(1):20–8. https://doiorg.publicaciones.saludcastillayleon.es/10.1111/j.1399-0004.2006.00628.x.

    Article  CAS  PubMed  Google Scholar 

  71. Araki S, Koya D, Makiishi T, Sugimoto T, Isono M, Kikkawa R, Kashiwagi A, Haneda M. APOE polymorphism and the progression of diabetic nephropathy in Japanese subjects with type 2 diabetes: results of a prospective observational follow-up study. Diabetes Care. 2003;26(8):2416–20. https://doiorg.publicaciones.saludcastillayleon.es/10.2337/diacare.26.8.2416.

    Article  CAS  PubMed  Google Scholar 

  72. Liu L, Xiang K, Zheng T, Zhang R, Li M, Li J. Co-inheritance of specific genotypes of HSPG and ApoE gene increases risk of type 2 diabetic nephropathy. Mol Cell Biochem. 2003;254(1–2):353–8. https://doiorg.publicaciones.saludcastillayleon.es/10.1023/a:1027364121738.

    Article  CAS  PubMed  Google Scholar 

  73. Ha SK, Park HS, Kim KW, Kim SJ, Kim DH, Kim JH, Lee HY, Han DS. Association between apolipoprotein E polymorphism and macroalbuminuria in patients with non-insulin dependent diabetes mellitus. Nephrol Dial Transpl. 1999;14(9):2144–9. https://doiorg.publicaciones.saludcastillayleon.es/10.1093/ndt/14.9.2144.

    Article  CAS  Google Scholar 

  74. Kimura H, Suzuki Y, Gejyo F, Karasawa R, Miyazaki R, Suzuki S, Arakawa M. Apolipoprotein E4 reduces risk of diabetic nephropathy in patients with NIDDM. Am J Kidney Dis. 1998;31(4):666–73. https://doiorg.publicaciones.saludcastillayleon.es/10.1053/ajkd.1998.v31.pm9531184.

    Article  CAS  PubMed  Google Scholar 

  75. Eto M, Horita K, Morikawa A, Nakata H, Okada M, Saito M, Nomura M, Abiko A, Iwashima Y, Ikoda A, et al. Increased frequency of apolipoprotein epsilon 2 allele in non-insulin dependent diabetic (NIDDM) patients with nephropathy. Clin Genet. 1995;48(6):288–92. https://doiorg.publicaciones.saludcastillayleon.es/10.1111/j.1399-0004.1995.tb04111.x.

    Article  CAS  PubMed  Google Scholar 

  76. Li J, Niu X, Li J, Wang Q. Association of PPARG gene polymorphisms Pro12Ala with type 2 diabetes mellitus: a meta-analysis. Curr Diabetes Rev. 2019;15(4):277–83. https://doiorg.publicaciones.saludcastillayleon.es/10.2174/1573399814666180912130401.

    Article  CAS  PubMed  Google Scholar 

  77. Syed R, Jamil K, Asimuddin M, Alqahtani MS, Alshehri M, Mateen A, Wahab Ali Aduderman A, Ola MS, Malik A. Molecular & biochemical analysis of Pro12Ala variant of PPAR-γ2 gene in type 2 diabetes mellitus. Saudi J Biol Sci. 2020;27(9):2439–43. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.sjbs.2020.06.046.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  78. Gouda HN, Sagoo GS, Harding AH, Yates J, Sandhu MS, Higgins JP. The association between the peroxisome proliferator-activated receptor-gamma2 (PPARG2) Pro12Ala gene variant and type 2 diabetes mellitus: a HuGE review and meta-analysis. Am J Epidemiol. 2010;171(6):645–55. https://doiorg.publicaciones.saludcastillayleon.es/10.1093/aje/kwp450.

    Article  PubMed  PubMed Central  Google Scholar 

  79. Luo W, Cao J, Li J, He W. Adipose tissue-specific PPARgamma deficiency increases resistance to oxidative stress. Exp Gerontol. 2008;43(3):154–63. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.exger.2007.11.002.

    Article  CAS  PubMed  Google Scholar 

  80. Thamer C, Haap M, Volk A, Maerker E, Becker R, Bachmann O, Machicao F, Häring HU, Stumvoll M. Evidence for greater oxidative substrate flexibility in male carriers of the pro 12 Ala polymorphism in PPARgamma2. Horm Metab Res. 2002;34(3):132–6. https://doiorg.publicaciones.saludcastillayleon.es/10.1055/s-2002-23196.

    Article  CAS  PubMed  Google Scholar 

  81. Vodosek Hojs N, Bevc S, Ekart R, Hojs R. Oxidative stress markers in chronic kidney disease with emphasis on diabetic nephropathy. Antioxid (Basel). 2020;9(10):925. https://doiorg.publicaciones.saludcastillayleon.es/10.3390/antiox9100925.

    Article  CAS  Google Scholar 

  82. Parwani K, Mandal P. Role of advanced glycation end products and insulin resistance in diabetic nephropathy. Arch Physiol Biochem. 2023;129(1):95–107. https://doiorg.publicaciones.saludcastillayleon.es/10.1080/13813455.2020.1797106.

    Article  CAS  PubMed  Google Scholar 

  83. Wang L, Teng Z, Cai S, Wang D, Zhao X, Yu K. The association between the PPARγ2 Pro12Ala polymorphism and nephropathy susceptibility in type 2 diabetes: a meta-analysis based on 9,176 subjects. Diagn Pathol. 2013;8:118. https://doiorg.publicaciones.saludcastillayleon.es/10.1186/1746-1596-8-118.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  84. Ding J, Zhu C, Mei X, Zhou Y, Feng B, Guo Z. Peroxisome proliferator-activated receptor γ Pro12Ala polymorphism decrease the risk of diabetic nephropathy in type 2 diabetes: a meta analysis. Int J Clin Exp Med. 2015;8(5):7655–60.

    PubMed  PubMed Central  Google Scholar 

  85. Marais AD. Apolipoprotein E in lipoprotein metabolism, health and cardiovascular disease. Pathology. 2019;51(2):165–76. https://doiorg.publicaciones.saludcastillayleon.es/10.1016/j.pathol.2018.11.002.

    Article  CAS  PubMed  Google Scholar 

  86. Herman-Edelstein M, Scherzer P, Tobar A, Levi M, Gafter U. Altered renal lipid metabolism and renal lipid accumulation in human diabetic nephropathy. J Lipid Res. 2014;55(3):561–72. https://doiorg.publicaciones.saludcastillayleon.es/10.1194/jlr.P040501.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  87. Rutledge JC, Ng KF, Aung HH, Wilson DW. Role of triglyceride-rich lipoproteins in diabetic nephropathy. Nat Rev Nephrol. 2010;6(6):361–70. https://doiorg.publicaciones.saludcastillayleon.es/10.1038/nrneph.2010.59.

    Article  CAS  PubMed  Google Scholar 

  88. Guan J, Zhao HL, Baum L, Sui Y, He L, Wong H, Lai FM, Tong PC, Chan JC. Apolipoprotein E polymorphism and expression in type 2 diabetic patients with nephropathy: clinicopathological correlation. Nephrol Dial Transpl. 2009;24(6):1889–95. https://doiorg.publicaciones.saludcastillayleon.es/10.1093/ndt/gfn734.

    Article  CAS  Google Scholar 

  89. Feng J, Wan G, Zhu X, Wang B, Yang Z. The apolipoprotein E (APOE) gene and the risk of diabetic nephropathy (DN): a meta-analysis in east Asian populations. Asian Biomed. 2010;4(2):329–35. https://doiorg.publicaciones.saludcastillayleon.es/10.2478/abm-2010-0041.

    Article  CAS  Google Scholar 

  90. Li Y, Tang K, Zhang Z, Zhang M, Zeng Z, He Z, He L, Wan C. Genetic diversity of the apolipoprotein E gene and diabetic nephropathy: a meta-analysis. Mol Biol Rep. 2011;38(5):3243–52. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s11033-010-9999-z.

    Article  CAS  PubMed  Google Scholar 

  91. Shi J, Cheng Z, Qiu S, Cui H, Gu Y, Zhao Q, et al. ε2 allele and ε2-involved genotypes (ε2/ε2, ε2/ε3, and ε2/ε4) may confer the association of APOE genetic polymorphism with risks of nephropathy in type 2 diabetes: a meta-analysis. Lipids Health Dis. 2020;19(1):136. https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12944-020-01307-6.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  92. Hu P, Qin YH, Jing CX, Lu L, Hu B, Du PF. Does the geographical gradient of ApoE4 allele exist in China? A systemic comparison among multiple Chinese populations. Mol Biol Rep. 2011;38(1):489–94. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s11033-010-0132-0.

    Article  CAS  PubMed  Google Scholar 

  93. Chen B, Cole JW, Grond-Ginsbach C. Departure from Hardy Weinberg equilibrium and genotyping error. Front Genet. 2017;8:167. https://doiorg.publicaciones.saludcastillayleon.es/10.3389/fgene.2017.00167.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  94. Zintzaras E. Impact of Hardy-Weinberg equilibrium deviation on allele-based risk effect of genetic association studies and meta-analysis. Eur J Epidemiol. 2010;25(8):553–60. https://doiorg.publicaciones.saludcastillayleon.es/10.1007/s10654-010-9467-z.

    Article  PubMed  Google Scholar 

  95. Salanti G, Amountza G, Ntzani EE, Ioannidis JP. Hardy-Weinberg equilibrium in genetic association studies: an empirical evaluation of reporting, deviations, and power. Eur J Hum Genet. 2005;13(7):840–8. https://doiorg.publicaciones.saludcastillayleon.es/10.1038/sj.ejhg.5201410.

    Article  CAS  PubMed  Google Scholar 

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Acknowledgements

Declared none.

Funding

This research was funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP19676488).

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Contributions

Study concept and design, B.T. and K.M.; data analysis and interpretation, B.T., K.M., and Z.S.; writing—original draft preparation, B.T.; writing—review and editing, B.T., K.A., and A.S.; supervision, A.S.; All authors have read and agreed to the published version of the manuscript.

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Correspondence to Binura Taurbekova.

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Supplementary Information

Additional file 1: Supplementary Method S1. Search strategies.

12882_2024_3859_MOESM2_ESM.xlsx

Additional file 2: Supplementary Table S1. Characteristics of included studies analyzing the association between PPARγ Pro12Ala polymorphism and DKD risk.

Additional file 3: Supplementary Table S2. Characteristics of included studies analyzing ApoE polymorphism.

12882_2024_3859_MOESM4_ESM.xlsx

Additional file 4: Supplementary Table S3. Definition of cases in studies analyzing the association between PPARγ Pro12Ala polymorphism and DKD risk. Supplementary Table S4. Definition of cases in studies analyzing the association between ApoE gene polymorphism and DKD risk.

12882_2024_3859_MOESM5_ESM.pdf

Additional file 5: Supplementary Figure S1. Begg’s funnel plots. A. PPARγ Pro12Ala; B.ApoE (ε3/ε4 vs. ε3/ε3); C.ApoE (ε4/ε4 vs. ε3/ε3); D.ApoE (ε2/ε2 vs. ε3/ε3); E.ApoE (ε2/ε3 vs. ε3/ε3); F.ApoE (ε2/ε4 vs. ε3/ε3). Supplementary Figure S2. Associations between gene polymorphisms and DKD risk after statistical model replacement. A.PPARγ Pro12Ala; B. ApoE (ε3/ε4 vs. ε3/ε3); C. ApoE (ε4/ε4 vs. ε3/ε3); D. ApoE (ε2/ε2 vs. ε3/ε3); E. ApoE (ε2/ε3 vs. ε3/ε3); F. ApoE (ε2/ε4 vs. ε3/ε3). Supplementary Figure S3. Associations between gene polymorphisms and DKD risk after excluding studies that violate Hardy-Weinberg equilibrium. A. PPARγ Pro12Ala; B. ApoE (ε3/ε4 vs. ε3/ε3); C. ApoE (ε4/ε4 vs. ε3/ε3); D. ApoE (ε2/ε2 vs. ε3/ε3); E. ApoE (ε2/ε3 vs. ε3/ε3); F. ApoE (ε2/ε4 vs. ε3/ε3).

12882_2024_3859_MOESM6_ESM.pdf

Additional file 6: Supplementary Figure S4. PRISMA flow diagram illustrating the process of selecting studies focused on investigating CETP. Supplementary Figure S5. PRISMA flow diagram illustrating the process of selecting studies focused on investigating LPL. Supplementary Figure S6. PRISMA flow diagram illustrating the process of selecting studies focused on investigating ACACB. Supplementary Figure S7. PRISMA flow diagram illustrating the process of selecting studies focused on investigating PPARγ. Supplementary Figure S8. PRISMA flow diagram illustrating the process of selecting studies focused on investigating ApoE.

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Taurbekova, B., Mukhtarova, K., Salpynov, Z. et al. The impact of PPARγ and ApoE gene polymorphisms on susceptibility to diabetic kidney disease in type 2 diabetes mellitus: a meta-analysis. BMC Nephrol 25, 436 (2024). https://doiorg.publicaciones.saludcastillayleon.es/10.1186/s12882-024-03859-6

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