Apolipoprotein E gene polymorphism, hypercholesterolemia and glomerular filtration rate in type 2 diabetic subjects: a 9-year follow-up study

Association of apoE gene polymorphisms with lipid metabolism in renal diseases

BACKGROUND AND OBJECTIVES

Apolipoprotein E (apoE) plays a central role in the metabolism and homeostasis of lipids. ApoE gene encodes three major isoforms: ε2, ε3 a nd ε4 forming six phenotypes: E2E2, E2E3, E2E4, E3E3, E3E3 and E4E4. Disorders of the lipid metabolism and the homeostasis are frequently coexist in renal diseases. The association between gene polymorphisms of apoE and lipid metabolism were not consistent. This meta-analysis was performed to assess the association between gene polymorphisms of apoE and lipid metabolism in renal diseases.

METHODS

A pre-defined literatures search and selection of eligible relevant investigations were performed to extract and collect data from electronic databases.

RESULTS

Sixteen articles were enrolled for the analysis of association between apoE gene polymorphisms and lipid metabolism. Subjects with E3E4 had a higher total cholesterol (TC) than those with E3E3, and subjects with E2E3 had a lower TC than those with E3E3. Subjects with ε2, had a lower TC than those with ε3 or ε4, and subjects with ε4 had a higher TC than those with, ε3. Subjects with E2E2, E2E3 or E4E4 had a higher triglyceride (TG) than those with E3E3. Subjects with ε4 had a higher TG than those with ε3. Subjects with ε2, had a higher level of TG than those with non-ε2. Subjects with E3E4 had a slightly lower high-density lipoprotein (HDL) than those with E3E3. E3E4 appeared to be associated with lower levels of HDL. Subjects with E2E2, E2E3 had a notably lower low-density lipoprotein (LDL) than those with E3E3. Subjects with ε2, had a lower LDL than those with ε3 or ε4 ApoE gene polymorphisms were not associated with very low-density lipoprotein, and lipoprotein (a) [Lp(a)]. Subjects with E2E3 or E2E4 had higher apoE levels than those with E3E3, and subjects with E4E4 had lower apoE levels than those with E3E3.

CONCLUSION

ApoE gene polymorphisms are associated with the expression of TC, TG HDL, LDL, Lp(a) or apoE.

Apolipoprotein E Gene Polymorphisms in Saudi Patients with Systemic Lupus Erythematosus

Apolipoprotein E (APOE) is a glycosylated protein with multiple biological properties. APOE gene polymorphism plays a central role in lipid metabolism and has recently been suggested to regulate inflammation. Our objective is to evaluate whether APOE polymorphism affects susceptibility to SLE. APOE genotyping was performed using ApoE StripAssay™ kit. Results indicated significantly higher frequencies of allele ε4 and genotype ε3/ε4 and lower frequencies of allele ε3 and genotype ε3/ε3 in SLE patients than controls. APOE ε2 allele was found in three patients, whereas it was absent in controls. The frequencies of allele ε4 and genotype ε3/ε4 were significantly higher in SLE patients with renal involvement and those of alleles ε2, ε4 and genotypes ε2/ε3, ε3/ε4 were higher in patients with neuropsychiatric symptoms. It is concluded that APOE allele ε4 is associated with susceptibility risk/clinical manifestations of SLE and ε2 may increase its severity while ε3 is protective for SLE in Saudis.

Association between Apolipoprotein E Polymorphism and Chronic Kidney Disease in the Korean General Population: Dong-gu Study

Background

Few studies have investigated the association between Apolipoprotein E (APOE) polymorphisms and chronic kidney disease (CKD) in the general population, and their results are inconsistent.

Methods

The current study population was composed of 9,033 subjects aged ≥ 50 years who participated in the baseline survey of the Dong-gu Study, which was conducted in Korea between 2007 and 2010. APOE polymorphisms were identified by polymerase chain reaction, and the estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease equation.

Results

Individuals with the APOE E2 allele had significantly lower total and low density lipoprotein cholesterol levels, those with the APOE E4 allele had lower high density lipoprotein (HDL) cholesterol levels, and those with the APOE E3 allele had lower log-triglyceride levels. Adjusting for covariates (sex, age, body mass index, smoking, systolic blood pressure, hypertension, diabetes, total cholesterol, HDL cholesterol, log-transformed triglycerides, and log-transformed albumin to creatinine ratio), mean eGFR was not significantly different among APOE alleles (E2, 69.4 mL/min/1.73 m²; E3, 69.5 mL/min/1.73 m²; E4, 69.4 ml/min/1.73 m²; P = 0.873). Additionally, the odds ratios (ORs) indicated that APOE polymorphisms were not independent risk factors for CKD (OR, 1.07; 95% confidence interval [CI], 0.91 to 1.26 for the E2 vs. E3 allele; OR, 1.01; 95% CI, 0.88 to 1.16 for the E4 vs. E3 allele).

Conclusion

APOE polymorphisms were not associated with either eGFR or CKD in the general Korean population.

Apolipoprotein E polymorphism and the progression of diabetic nephropathy in type 2 diabetes

BACKGROUND/AIMS

Three different apo E alleles (E2, E3 and E4) produce apo E isoproteins, which regulate the metabolism of lipoproteins. This study investigated the apo E polymorphisms as a prognostic factor for the development of diabetic nephropathy (DN).

METHODS

A total of 525 type 2 diabetic patients were enrolled to participate in this prospective observational study. Apo E gene polymorphisms were analyzed by polymerase chain reaction. The progression of DN was defined as a shift to a higher stage of DN or a doubling of the baseline serum creatinine level by the end of the study.

RESULTS

The mean follow-up period was 42.4 months. The patients whose DN progressed had significantly higher urine albumin/creatinine ratios and fewer used diuretics than those in whom DN did not progress. In the Cox regression analysis, the apo E4 carriers were found to be at greater risk of progression of DN than non-apo E4 carriers (p = 0.007, hazard ratio 2.252). After adjusting for confounding factors, apo E4 carriers remained at increased risk of progression to more severe DN (p = 0.002, hazard ratio 2.820).

CONCLUSION

Our study suggests the apo E4 carrier might serve as a predictor of DN progression in Taiwan.

Genetic variation of apolipoprotein E does not contribute to the lipid abnormalities secondary to childhood minimal change nephrotic syndrome

Minimal change nephrotic syndrome (MCNS) is a common progressive renal disorder occurring in childhood that is characterized by alterations of permselectivity at the glomerular capillary wall, resulting in its inability to restrict the urinary loss of protein. Hyperlipidemia (HLP) is not only an important clinical manifestation of MCNS but is also involved in cardiovascular disease and in progressive renal damage. ApoE is a polymorphic protein. Besides modulation of lipid metabolism, apoE can also elevate the sulfate-proteoglycan in glomerular filtration membrane and inhibit the proliferation of mesengial cells. The present study aimed mainly to determine whether genetic polymorphism of apoE is involved in the HLP secondary to childhood MCNS. Genomic DNA was extracted from 250 children diagnosed with MCNS and 200 healthy controls. ApoE genotype was determined by PCR-restriction fragment length polymorphism (RFLP) analysis. The fasting serum lipoprotein (a) [Lp(a)], total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), apolipoprotein A1 (apoA1), and apoB were measured. Serum concentrations of Lp(a), TC, TG, HDL-C, nonHDL-C, LDL-C, and apoB were higher in the MCNS than in the control group (P < 0.05). No significant differences in genotypes and alleles frequencies were observed for the apoE Hha I restriction sites in MCNS patients as compared to controls (P > 0.05). No significant differences in serum lipid levels were observed for variant genotypes and alleles of apoE Hha I restriction site in both MCNS and healthy children (P > 0.05). Genetic variation of apoE does not contribute to the lipid abnormalities secondary to childhood MCNS.

Apolipoprotein E polymorphism and expression in type 2 diabetic patients with nephropathy: clinicopathological correlation

BACKGROUND

Diabetic nephropathy represents a heterogeneous group of renal pathologies that may be associated with genetic susceptibility. There have been clinical reports on the risk association of diabetic nephropathy with an apolipoprotein E (ApoE) exon 4 polymorphism although its correlations with renal histopathological changes have not been explored.

METHODS

A total of 213 adult autopsies with type 2 diabetes and 111 non-diabetic control cases were analysed. Genomic DNA samples were obtained from spleen tissues. The ApoE genotype was determined by PCR-LDR analysis. Histopathological examination of kidney sections was performed in a subset of 51 diabetic and 111 control cases. ApoE protein expression in diabetic carriers with similar clinical status was examined by immunohistochemical staining.

RESULTS

In type 2 diabetes, epsilon2 carriers (P = 0.04; odds ratio = 5.42; 95% CI: 1.10-26.8) and epsilon3/epsilon4 (P = 0.04; odds ratio = 22.5; 95% CI: 1.11-454.90) genotype carriers were more likely to have glomerular hypertrophy than were epsilon3/epsilon3 carriers. The epsilon2 carriers showed an increase in glomerular ApoE protein expression. A correlation between ApoE genotype and nodular glomerulosclerosis was not found.

CONCLUSIONS

Our findings confirm the risk association of the ApoE polymorphism with diabetic nephropathy in clinical studies and is the first study demonstrating the correlations between ApoE genotypes, protein expression and structural changes in diabetic nephropathy.

Type 2 diabetes mellitus and its renal complications in relation to apolipoprotein E gene polymorphism

The apolipoprotein E (APOE) epsilon2 allele is reported to be associated with greater risk of renal impairment in type 2 diabetes. Relationships among APOE polymorphisms, renal impairment, and biochemical parameters were explored. A prospective study of 405 consenting Chinese type 2 diabetic patients [mean age +/- standard deviation (SD): 59.2 +/- 10.3 years] without advanced complications at entry was conducted. APOE genotyping and measurement of plasma biomarkers of oxidative stress and antioxidants were performed at entry. HbA1C, plasma glucose, lipids, creatinine, urine albumin/creatinine, and blood pressure were measured at entry and at up to 4 years of follow-up. APOE allelic frequencies were in Hardy-Weinberg equilibrium. Odds ratios of albuminuria at entry and/or during follow-up for different APOE groups were not significantly different. The non-epsilon2 (epsilon3/3, epsilon3/4, epsilon4/4) group had significantly greater plasma ascorbate (51.6 +/- 20.1 mumol/L) than the epsilon2 (epsilon2/2, epsilon2/3) group (44.5 +/- 16.2 mumol/L, P = 0.021), but higher plasma ascorbate levels did not seem to decrease the risk of renal impairment in the non-epsilon2 group. Baseline plasma lipid-standardized alpha-tocopherol levels were least in epsilon2 subjects with persistent albuminuria (3.6 +/- 1.1 mumol/mmol of total cholesterol plus triglycerides, P = 0.008) compared with epsilon2 subjects who had no albuminuria at entry or during follow-up (4.5 +/- 0.8 mumol/mmol of total cholesterol plus triglycerides). The APOE epsilon2 allele does not seem to be associated with increased risk of renal impairment in Chinese type 2 diabetic patients. Plasma lipid-standardized alpha-tocopherol may play a role in determining risk of renal dysfunction in type 2 diabetes.

Association of APOE (Hha1) and ACE (I/D) gene polymorphisms with type 2 diabetes mellitus in North West India

Familial and epidemiological studies have shown that genetic factors play a role in the development and progression of type 2 diabetes mellitus (T2DM). Asian Indians have shown an increasing prevalence of T2DM. Apolipoprotein E (APOE) and Angiotensin-1 converting enzyme (ACE) I/D polymorphisms have been associated with T2DM. This study examined the association of APOE and ACE genes with T2DM patients of Punjab, India. APOE (HhaI) and ACE (I/D) genotypes analysed by polymerase chain reaction were available from 90 patients and 97 random healthy controls. All loci and populations are in Hardy-Weinberg equilibrium. There is no significant association of APOE vis-à-vis T2DM, however APOE*4 allele frequency is low in diabetics (3.9% and 8.8%). DD genotype and *D allele of ACE are associated with T2DM (OR=1.90, p<0.05, and OR=1.58, p<0.05, respectively). Recessive and multiplicative mode of inheritance for *D allele provided the strongest support for the association. Height, weight and BMI did not reveal any significant association with APO or ACE. DD-33 and ID-23 combinations (ACE-APOE) showed higher odds of 2.01 and 2.14, respectively. ACE but not APOE polymorphism is positively associated with T2DM in Indian population, however, the synergistic effects of DD-33 and ID-23 are also evident.

A retrospective study on the influence of apolipoprotein e and serum lipids in progressive renal failure

BACKGROUND

Progression of renal failure is associated with altered lipoprotein metabolism. Apolipoprotein E polymorphism is an important genetic marker for dyslipidemia. The main purpose of this retrospective study was to examine the influence of apolipoprotein E polymorphism and serum lipids level on the progression rate in a group of patients with kidney diseases of diverse etiology.

METHODS

Progression rate, with regard to apolipoprotein E polymorphism and initial serum creatinine value, median (162 micromol/l), was determined by reviewing the charts of 385 patients on renal replacement therapy with a median follow-up time of 4.85 years.

RESULTS

Progression rate was negatively correlated to serum cholesterol in the group with type 2 diabetes (p= 0.001). In addition, the urine albumin excretion rate (UAER) was higher in type 2 diabetics carrying the epsilon2 allele (2.1 g/l) as compared to non-epsilon2 allele carriers (1.2 g/l) (p=0.009). Although serum cholesterol in patients with autosomal dominant polycystic kidney disease (ADPKD) carrying the apolipoprotein epsilon4 allele was 5.87 +/- 1.0 mmol/l, which was significantly higher compared to non-epsilon4 carriers, 4.97 +/- 1.1 mmol/l (p=0.026), progression rate was similar in the two groups, 4.4 +/- 0.8 micromol/l/year. An increase in the relative frequency of the apolipoprotein epsilon4 allele was found in patients with ADPKD (0.29), as compared to (0.16) in the rest of the diagnostic groups (p=0.0023). In addition, in the whole study population a positive correlation was found between progression rate and underlying disease (p < 0.005), UAER (p < 0.005) and blood pressure (p < 0.005).

CONCLUSIONS

The results of the present study indicate that the decline of renal function in patients with diabetes type 2 may not be associated with levels of plasma cholesterol, but with triglyceride lipoproteins, considered remnant lipoproteins. Any association between cholesterol and apolipoprotein epsilon4 allele with progression in ADPKD may not necessarily be straightforward since this disease is influenced by other genetic and unidentified factors.

Impact of Lipoprotein Glomerulopathy on the Relationship Between Lipids and Renal Diseases

Lipoprotein glomerulopathy (LPG) is a unique entity of renal lipidosis characterized by peculiar histopathologic characteristics of lipoprotein thrombi and an abnormal plasma lipoprotein profile resembling type III hyperlipoproteinemia, with a marked increase in serum apolipoprotein E (apoE) concentrations. At present, 65 cases have been reported worldwide, although most patients are found in Japan and east Asian countries. Recently, we identified 4 types of novel apoE mutations associated with LPG. In particular, a mutation designated apoE Sendai, in which arginine 145 is substituted with proline, occurs in the majority of Japanese patients. The virus-mediated transduction of apoE Sendai resulting in the development of LPG in apoE-deficient mice confirms the etiologic role of apoE mutation in LPG. Conversely, experimental graft-versus-host disease induced in Fc receptor gamma-chain-deficient mice showed LPG-like lesions in glomeruli without apoE mutations. Considered together, we believe that intrinsic factors in the kidney also contribute to the induction of LPG. Today, apoE and related lipid abnormalities are reported to have an important role in the development of various renal diseases, eg, diabetic nephropathy and immunoglobulin A nephropathy. In this article, we review clinical and histopathologic features of LPG, describe the etiologic role of apoE variants and intrinsic renal factors, and discuss the impact of LPG on mechanisms of other renal diseases.

Association of CETP TaqI and APOE polymorphisms with type II diabetes mellitus in North Indians: a case control study

BACKGROUND

Genetic variants of proteins involved in lipid metabolism may play an important role in determining the susceptibility for complications associated with type II diabetes mellitus (T2DM). Goal of the present study was to determine the association of cholesteryl ester transfer protein TaqI B, D442G, and APOE Hha I polymorphisms with T2DM and its complications.

METHODS

Study subjects were 136 patients and 264 healthy controls. All polymorphisms were detected using PCR-RFLP and statistical analysis done with chi2 test and ANOVA.

RESULTS

Although CETP TaqI B polymorphism was not associated with the T2DM, yet B1B2 genotype was significantly (p = 0.028) associated with high risk of hypertension in diabetic patients (OR = 3.068, 95% CI 1.183-7.958). In North Indians D442G variation in CETP gene was found to be absent. Frequency of APOE HhaI polymorphism was also not different between patients and controls. In diabetic patients having neuropathy and retinopathy significantly different levels of total-cholesterol [(p = 0.001) and (p = 0.029) respectively] and LDL-cholesterol [(p = 0.001) and (p = 0.001) respectively] were observed when compared to patients with T2DM only. However, lipid levels did not show any correlation with the CETP TaqI B and APOE Hha I genetic polymorphisms.

CONCLUSION

CETP TaqI B and APOE HhaI polymorphism may not be associated with type II diabetes mellitus in North Indian population, however CETP TaqI B polymorphism may be associated with hypertension along with T2DM.

Influence of apolipoprotein E polymorphisms on serum creatinine levels and predicted glomerular filtration rate in healthy subjects

BACKGROUND

There are conflicting results regarding the effect of apolipoprotein (ApoE) polymorphisms on the progression of a variety of renal diseases. However, there are no data on the possible effect of the ApoE alleles on serum creatinine levels and predicted glomerular filtration rate (GFR) in healthy subjects.

METHODS

290 apparently healthy individuals were studied. ApoE genotyping was performed by the polymerase chain reaction; the Modification of Diet in Renal Disease equation (MDRD) predicted the GFR.

RESULTS

ApoE2 was associated with lower levels of total cholesterol, low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol, as well as with higher levels of triglycerides in our population. Furthermore, the ApoE2 allele was associated with increased serum creatinine levels compared with both the E3 and E4 alleles (1.04+/-0.13 vs 0.92+/-0.13 vs 0.88+/- 0.11 mg/dl, respectively, P = 0.0077), while the MDRD-predicted GFR was decreased in ApoE2 carriers compared with both E3 and E4 carriers (80.3+/-10.2 vs 88.1+/-9.6 vs 89.3+/-9.7 ml/min/1.73 m(2), respectively, P = 0.031). These observations remained significant statistically even if the effect of ApoE polymorphisms on age- and body-mass index-adjusted serum creatinine and MDRD-predicted GFR was separately analysed in both men and women. Although, ApoE4 carriers tended to exhibit lower levels of serum creatinine and higher values of predicted GFR compared with the E3 carries, these differences did not reach statistical significance.

CONCLUSIONS

ApoE2 allele seems to be associated with increased serum creatinine levels and decreased MDRD-predicted GFR in healthy subjects.

Apolipoprotein E and renal disease

Apolipoprotein E (ApoE) is a major constituent of plasma lipoproteins with many biological actions of great significance. Beyond the known influence of ApoE polymorphisms on serum lipid profile, the pathogenesis of atherosclerosis, and the development of neurodegenerative disorders, ApoE also has a major role in the pathogenesis and progression of a variety of renal diseases, as well as in the atherosclerotic complications associated with them. Briefly, the polymorphisms of ApoE are major determinants of plasma lipid levels in uremic patients. They may affect the risk for cardiovascular disease in this population, predispose to the development of diabetic nephropathy, influence the severity of certain glomerulopathies, and regulate mesangial and glomerular functions locally in the kidney microenvironment. Finally, certain mutations of the ApoE gene are associated with a recently described nephropathy, termed lipoprotein glomerulopathy.