Effect of angiotensin-converting enzyme gene insertion/deletion polymorphism and angiotensin-converting enzyme inhibition on erythropoiesis in patients on haemodialysis

Haematological Indicators of Response to Erythropoietin Therapy in Chronic Renal Failure Patients on Haemodialysis: Impact of Angiotensin-Converting Enzyme rs4343 Gene Polymorphism

PURPOSE

This is the first cross-sectional study studying the changes in haematological indicators of the response to recombinant human erythropoietin (rHuEPO) therapy in chronic renal failure (CRF) patients on haemodialysis (HD) stratified according to ACE G2350A (rs4343) gene polymorphism.

DESIGN

An observational cross-sectional study.

SETTING

Nephrology department and Biochemistry and molecular biology department, faculty of medicine, Cairo University.

PATIENTS

A total of 256 CRF patients on HD for at least six months (162 male and 103 female) and 160 healthy subjects (122 male and 38 female) were recruited in the current study after signing a consent form. ACE G2350A (rs4343) Insertion/Deletion (I/D) was tested, the association between ACE G2350A (RS4343) gene polymorphisms and patients response to rHuEpo was evaluated.

RESULTS

ACE G2350A (rs4343) I/D was the most prevalent genotype, while I/I genotype was the lowest prevalent among patient or control subjects included in the study. D allele is the most prevalent allele, either among patients or the control group. Hemoglobin (Hb) level in patients with I/I and Deletion/Deletion (D/D) genotype was significantly higher compared to those with I/D genotype (P = 0.012 and P = 0.005, respectively). Serum iron in the I/D genotype was significantly higher than those with either I/I or D/D genotype (P = 0.045 and P = 0.018, respectively). Angiotensin-converting enzyme (ACE) content, total leukocytic count (TLC), and soluble erythropoietin receptor (sEpoR) were independent predictors of Hb level. The ACE gene, TLC, and serum iron were the independent factors that may affect the Haematocrit (Hct) level. ACE G2350A (rs4343) gene polymorphisms may affect the HD patient's responses to rHuEPOs.

CONCLUSION

In HD patients, screening for ACE G2350A (rs4343) gene polymorphisms before rHuEpo administration may help predict patient response.

Erythropoietin Resistance in Patients with Chronic Kidney Disease: Current Perspectives

Anemia is a frequent complication of chronic kidney disease, and its primary cause is erythropoietin deficiency. After diagnosis, treatment begins with administration of an erythropoiesis-stimulating agent (ESA). However, some patients present with resistance to ESA, which needs to be reversed, as it can increase the risk of death in patients with kidney disease. Therefore, we provide a discussion of the current literature regarding the factors that can modify the response to this class of drugs and the strategies that can be considered to optimize the benefits of treating anemia.

ACE gene polymorphism and its association with serum erythropoietin and hemoglobin ‎in Iraqi hemodialysis patients

Purpose

To evaluate the frequencies of angiotensin-converting enzyme gene ‎polymorphism in ‎Iraqi hemodialysis patients and to examine the association ‎between this polymorphism and ‎serum erythropoietin and hemoglobin levels.‎.

Methods

In this study, 70 chronic renal failure Iraqi patients on ‎maintenance ‎hemodialysis (patient group) and 20 healthy subjects (control ‎group) were genotyped for ‎angiotensin-converting enzyme gene polymorphism. The distribution of genotype and allele ‎frequencies of this polymorphism in ‎these subjects were also evaluated.‎.

Results

The distribution of angiotensin-converting enzyme genotypes between ‎groups was ‎similar, and the ID genotype was the most frequent, followed by DD and II ‎genotypes (‎50%‎, ‎37%‎, and ‎13%). The control group ‎had a nonsignificant difference in serum ‎erythropoietin levels among different angiotensin-converting enzyme genotypes, ‎while patients with ID and DD genotypes displayed significant ‎elevation in ‎serum erythropoietin with time. No significant differences in hemoglobin ‎levels ‎were observed in patient and control groups. A significant positive correlation ‎was ‎observed between serum erythropoietin and hemoglobin in the control group ‎with different ‎angiotensin-converting enzyme genotypes, while a nonsignificant ‎negative correlation was ‎observed in the patient group throughout the study. ‎.

Conclusions

Chronic kidney disease did not significantly alter angiotensin-converting enzyme ‎genotypes, and angiotensin-converting enzyme gene ‎polymorphism had a significant effect on ‎serum erythropoietin levels and a non‎significant effect on hemoglobin levels. ‎.

Genetically-reduced serum ACE activity might be a causal risk factor for obstructive sleep apnea syndrome: A meta-analysis

We meta-analytically summarized the associations of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism with ACE activity and obstructive sleep apnea syndrome (OSAS) to see whether ACE activity is causally associated with OSAS. Literature search and data abstraction were done in duplicate. Sixteen articles including 2060 OSAS patients and 1878 controls were summarized. Overall, no significance was observed for the association of I/D polymorphism with OSAS, whereas carriers of II genotype (weighted mean difference or WMD, 95% confidence interval or CI, P: −11.976, −17.168 to −6.783, <0.001) or I allele (−9.842, −14.766 to −4.918, <0.001) had a lower level of serum ACE activity compared with DD genotype carriers, respectively. In subgroup analyses, carriers of II genotype were 3.806 times more likely to develop OSAS (95% CI, P: 1.865 to 7.765, <0.001) in OSAS patients with hypertension, without heterogeneity. Mendelian randomization analysis indicated there was 37.4% (95% CI: 1.115 to 3.142) and 32.4% (1.106 to 2.845) increased risk of OSAS by a reduction of 1 U/L in ACE activity for the II genotype and I allele carriers versus DD genotype carriers, respectively. There was no observable publication bias. Collectively, genetically-reduced serum ACE activity might be a causal risk factor for OSAS.

Interaction between angiotensin-converting enzyme gene insertion/deletion polymorphism and angiotensin-converting enzyme inhibition on survival in hemodialyzed patients

The association between ACE (angiotensin-converting enzyme) gene insertion/deletion (I/D) polymorphism and mortality has been inconsistently observed in earlier studies in patients on maintenance hemodialysis. We hypothesized that the effect of ACE gene I/D polymorphism on mortality may be influenced by concurrent ACE inhibitor therapy in this population. In this prospective, multicenter cohort, observational study, data was collected from 716 prevalent chronic hemodialysis patients, blood samples were genotyped for I/D single nucleotide polymorphism. Patient mortality was assessed in tree genotype groups insertion/insertion, insertion/deletion and deletion/deletion (I/I, I/D, and D/D) using multivariate Cox proportional hazard models. The most frequent genotype was I/D (42.6%), followed by D/D (37.7%) and I/I (19.7%) genotypes. The mean age was 54.9±15.5 years, 53.2% of all patients were male and in the total group the prevalence of diabetes was 19.3%. ACE inhibitor therapy was prescribed for 47.9% of all patients. The median duration of dialysis before blood sampling was 23.8 months (IQR 11.2-47.1). Patients were followed for 10 years, the median follow-up time was 29.8 months (IQR 12.6-63.4). Patient characteristics were well balanced among the genotype groups. D/D genotype, was associated with inferior survival (I/I vs D/D: log-rank test: P=0.04) in patients not receiving ACE inhibitor therapy, and the presence of this therapy diminished this difference. There was no difference in survival among unselected patients with different genotypes. In multivariate Cox regression models, D/D genotype (compared to I/I) was a significant predictor of mortality only in patients without ACE inhibitor therapy (HR 0.67, 95% CI 0.46-0.97, P=0.03). Our data suggests that hemodialyzed patients with the deletion/deletion (D/D) genotype might have inferior outcome, and ACE inhibitor therapy may be associated with improved survival in this subgroup.