Angiotensin-Converting Enzyme Gene Polymorphism Is Correlated to the Progression of Disease in Patients with IgA Nephropathy: A Metaanalysis

The Influence of ACE Insertion/Deletion Gene Polymorphism on the Risk of IgA Nephropathy: A Debatable Topic

Background

The connection between angiotensin-converting enzyme insertion/deletion (ACE I/D) gene polymorphisms and IgA nephropathy (IgAN) was conflicting. This pooled analysis was performed to explore this issue.

Methods

All eligible investigations were identified from various electronic databases, and the pooled analysis was evaluated using Stata software.

Results

27 studies with 2538 IgAN cases and 3592 controls were included. In overall subjects, ACE D allele, DD, and II genotype were associated with IgAN susceptibility (D vs. I: OR = 1.21, 95% CI: 1.10–1.32, P < 0.001; DD vs. ID + II: OR = 1.38, 95% CI: 1.20–1.60, P < 0.001; and II vs. DD + ID: OR = 0.83, 95% CI: 0.73–0.95, P=0.007). In Asian and Chinese patients, ACE I/D gene polymorphism was also correlated with IgAN vulnerability. Moreover, ACE D allele, DD, and II genotype were correlated with the progression of IgAN (D vs. I: OR = 1.37, 95% CI: 1.09–1.73, P=0.008; DD vs. ID + II: OR = 1.57, 95% CI: 1.06–2.31, P=0.024; and II vs. DD + ID: OR = 0.69, 95% CI: 0.49–0.99, P=0.045). Conversely, in Caucasian subjects, there was no link between ACE I/D gene polymorphism and the risk of IgAN.

Conclusion

ACE I/D gene polymorphism was correlated with the vulnerability and progression of IgAN in Asian and Chinese patients, and ACE D allele and DD homozygote genotype could be adverse factors for IgAN, while the II homozygote genotype could be an advantage factor. But, no significant association was found between ACE I/D gene polymorphism and IgAN in Caucasians.

The angiotensin-I converting enzyme gene I/D variation contributes to end-stage renal disease risk in Chinese patients with type 2 diabetes receiving hemodialysis

Whether the DD genotype of the angiotensin-I converting enzyme (ACE) I/D variation contributes to end-stage renal disease (ESRD) risk in type 2 diabetes mellitus (T2DM) remains controversial. Differences in study design, case and control definition, sample size and ethnicity may contribute to the discrepancies reported in association studies. We performed a case-control study to evaluate the association of the ACE I/D variation with ESRD risk in Chinese patients with T2DM receiving hemodialysis and analyzed the genotype-phenotype interaction. Unrelated Chinese patients (n = 432) were classified into the non-diabetic nephropathy (DN) control group (n = 222, duration of diabetes >10 years, no signs of renal involvement) and the DN-ESRD group (n = 210; ESRD due to T2DM, receiving hemodialysis). Polymerase chain reaction was used to genotype ACE I/D for all 432 subjects. The frequencies of the ID + DD genotypes were higher in the DN-ESRD group than non-DN control group (65.2 vs. 50.9 %; adjusted OR 1.98 (95 % CI, 1.31-3.00; P = 0.001). In the DN-ESRD group, the DD genotypic subgroup had significantly elevated HbA1c and diastolic blood pressure (DBP) compared to the II subgroup (both P < 0.05). The DD genotype of the ACE I/D variation may be associated with more elevated blood pressure and HbA1c, and therefore may predict the development, progression and severity of DN-ESRD in Chinese patients with T2DM undergoing hemodialysis.

Gene polymorphisms contributing to hypertension in immunoglobulin A nephropathy

BACKGROUND

Hypertension, which is affected by genetic and environmental factors, is one of the major risk factors for chronic kidney disease. Identification of the genetic factor contributing to hypertension in patients with chronic kidney disease may potentially refine a therapeutic strategy.

METHODS

In the present multicenter cross-sectional study, 240 patients were eligible (aged 15-50 years with urinary protein ≥0.25 g/day) out of 429 patients who were diagnosed as having immunoglobulin (Ig) A nephropathy (IgAN) by renal biopsy between 1990 and 2005 and enrolled in our previous study, PREDICT-IgAN. The outcome was hypertension defined as ≥140 and/or ≥90 mmHg of systolic and diastolic blood pressure and/or use of antihypertensives at renal biopsy. We assessed associations between hypertension and 28 polymorphisms with the frequency of minor genotype ≥10% among 100 atherosclerosis-related polymorphisms using the Chi-squared test in dominant and recessive models. We identified polymorphisms associated with hypertension in multivariate logistic regression models.

RESULTS

Baseline characteristics: hypertension 36.3%. Among 28 polymorphisms, the Chi-squared test revealed that CD14 (-159CC vs CT/TT, P = 0.03) and ACE (DD vs DI/II, P = 0.03) were significantly associated with hypertension after Bonferroni correction. Multivariate logistic regression models revealed that CD14 -159CC [vs CT/TT, odds ratio (OR) 3.58 (95% confidence interval (CI) 1.66-7.63)] and ACE DD [vs DI/II, OR 4.41 (95% CI 1.80-10.8), P = 0.001] were independently associated with hypertension.

CONCLUSIONS

CD14 C-159T and ACE I/D contributed to hypertension in patients with IgAN.

Unravelling the genetic basis of renal diseases; from single gene to multifactorial disorders

Chronic kidney disease is common with up to 5% of the adult population reported to have an estimated glomerular filtration rate of < 60 ml/min/1.73 m(2). A large number of pathogenic mutations have been identified that are responsible for 'single gene' renal disorders, such as autosomal dominant polycystic kidney disease and X-linked Alport syndrome. These single gene disorders account for < 15% of the burden of end-stage renal disease that requires dialysis or kidney transplantation. It has proved more difficult to identify the genetic susceptibility underlying common, complex, multifactorial kidney conditions, such as diabetic nephropathy and hypertensive nephrosclerosis. This review describes success to date and explores strategies currently employed in defining the genetic basis for a number of renal disorders. The complementary use of linkage studies, candidate gene and genome-wide association analyses are described and a collation of renal genetic resources highlighted.

Angiotensin-Converting Enzyme Inhibitor versus Angiotensin 2 Receptor Antagonist Therapy and the Influence of Angiotensin-Converting Enzyme Gene Polymorphism in IgA Nephritis

Introduction: In this study of 109 patients with IgA nephritis (IgAN), we compared the long term effects on patients treated with angiotensin converting enzyme inhibitor (ACEI) or angiotensin receptor antagonist (ATRA) alone with respect to renal outcome in terms of ESRF from 1995 to 2006. The renal outcome is also correlated with the ACE gene ID polymorphism to study its influence on response to ACEI/ATRA therapy. Materials and Methods: Seventy-seven patients were on treatment with ACEI/ATRA (22 on ACEI alone, 47 on ATRA alone and 8 on both). The other 32 patients were on no treatment (control group). Results: Compared to controls, treated patients had lower serum creatinine (P<0.001), lower proteinuria (P<0.001) and fewer number progressing to ESRF (P<0.001). For those with the II and ID genotype there were significantly fewer patients with ESRF in the treatment group. With the DD genotype, treatment did not change the poor renal outcome with regard to ESRF. Patients on ACEI therapy had a higher incidence of ESRF compared to those on ATRA (P<0.001). For the control group, the projected number of years-to-ESRF was 10 years. For those on ACEI therapy it was 11 years, and for those on ATRA therapy it was 24 years. Among patients with the II genotype, those treated with ATRA had significantly less incidence of ESRF compared to those treated with ACEI (P<0.001). Conclusion: ATRA therapy was found to be effective in retarding disease progression to ESRF in IgAN compared to ACEI therapy. Genotyping showed better response to ATRA therapy only for those with the II genotype. Key words: End-stage renal failure, Genotyping, Reciprocal creatinine plots