Angiotensin-converting enzyme gene polymorphism and vascular manifestations in Korean patients with SLE

Association of angiotensin-converting enzyme (ACE) I/D variation with biochemical parameters and oxidative stress markers in systemic lupus erythematosus patients in west of Iran

PURPOSE

We aimed to study insertion/deletion (I/D) variation (rs4646994) of ACE gene in a group of SLE patients in west of Iran and its possible relationship with oxidative stress.

METHOD AND RESULTS

Genotypes and allele frequencies related to ACE (I/D) variation were determined in 108 SLE patients and 110 gender and age-matched healthy controls using PCR. Neopterin, malondialdehyde (MDA), and serum lipid concentrations were determined by HPLC and enzyme assay respectively. The overall distribution of ACE I/D genotypes in SLE patients was different from that of the control group (P = 0.005). DD genotype compared to ID genotype increased the risk of SLE (OR = 2.57, 95% CI 1.4-4.8, P = 0.003). ID genotype compared to the II genotype decreased the risk of disease (OR = 0.45, 95% CI 0.2-0.99, p = 0.042). SLE patients with DD, ID, and II genotypes had lower paraoxonase (PON) activity and higher serum levels of MDA and neopterin versus control patients. We also detected a significant protective effect against SLE in presence of ACE I alleles and lack of angiotensin II receptor, type 1 (AGTR1) A1166C (NCBI reference SNP id: rs5186), C alleles in this study (OR = 0.31, 95% CI 0.14-0.68, P = 0.002).

CONCLUSIONS

Carriers of the DD genotype of ACE gene with higher serum concentrations of neopterin and MDA, and lower PON activity had a high risk to develop SLE, while ID genotype decreased the risk of disease development by 2.22 times compared to II genotype.

Angiotensin converting enzyme (ACE)

BACKGROUND

Angiotensin converting enzyme (ACE) was isolated as a 'hypertensinconverting enzyme'. There have been considerable advances in understanding the metabolic role of ACE in the body. This review attempts to highlight the role of ACE enzyme in the physiological and pathological processes occurring in the organs in which it is localized.

METHODS

The literature was searched from the websites of the National Library of Medicine (http://www.ncbi.nlm.nih.gov/) and Pub Med Central, the U.S. National Library of Medicine's digital archive of life sciences journal literature.

RESULTS

The involvement of ACE in regulation of blood pressure forms its central action but it has a role to play in a variety of physiological processes occurring in the organs in which it is localized like the lungs, macrophages, brain, pancreas, liver etc. It has also been implicated in the pathogenesis of a number of diseases including COVID-19.

CONCLUSIONS

More studies need to be carried out in order to validate the use of ACE levels in the diagnosis and monitoring of the diseases associated, and facilitate the use of ACE inhibitors and Angiotensin Receptor Blockers in the management of the same, so this wonder molecule can be utilized to its full potential.

Upregulation of Proinflammatory Bradykinin Peptides in Systemic Lupus Erythematosus and Rheumatoid Arthritis

Our recent study has implicated bradykinin (BK) signaling as being of pathogenic importance in lupus. This study aims to investigate the biomarker potential of BK peptides, BK and BK-des-arg-9, in lupus and other rheumatic autoimmune diseases. Sera from systemic lupus erythematosus (SLE) patients and healthy subjects were screened for BK and BK-des-arg-9 by liquid chromatography-mass spectrometry metabolomics. Serum from 6-mo-old C57BL/6 mice and three murine lupus strains were also screened for the two peptides by metabolomics. Given the promising initial screening results, validation of these two peptides was next conducted using multiple reaction monitoring in larger patient cohorts. In initial metabolomics screening, BK-des-arg-9 was 22-fold higher in SLE serum and 106-fold higher in mouse lupus serum compared with healthy controls. In validation assays using multiple reaction monitoring and quadrupole time-of-flight mass spectrometry, BK and BK-des-arg-9 showed significant elevations in SLE serum compared with controls (p < 0.0001; area under the curve = 0.79-0.88), with a similar but less pronounced increase being noted in rheumatoid arthritis serum. Interestingly, increased renal SLE disease activity index in lupus patients was associated with reduced circulating BK-des-arg-9, and the reasons for this remain to be explored. To sum, increased conversion of BK to the proinflammatory metabolite BK-des-arg-9 appears to be a common theme in systemic rheumatic diseases. Besides serving as an early marker for systemic autoimmunity, independent studies also show that this metabolic axis may also be a pathogenic driver and therapeutic target in lupus.

Angiotensin-Converting Enzyme Gene I/D Polymorphism Is Associated With Systemic Lupus Erythematosus Susceptibility: An Updated Meta-Analysis and Trial Sequential Analysis

Angiotensin-converting enzyme (ACE) gene is indispensable for endothelial control and vascular tone regulatory systems, usually affected in Systemic Lupus Erythematosus (SLE). ACE insertion/deletion (I/D) polymorphism may influence the progress of SLE. Earlier studies have investigated this association without any consistency in results. We performed this meta-analysis to evaluate the precise association between ACE I/D polymorphism and SLE susceptibility. The relevant studies were searched until December, 2017 using Medline (PubMed), Google-Scholar and EMBASE search engines. Twenty-five published studies involving 3,308 cases and 4,235 controls were included in this meta-analysis. Statistically significant increased risk was found for allelic (D vs. I: p = 0.007; OR = 1.202, 95% CI = 1.052–1.374), homozygous (DD vs. II: p = 0.025; OR = 1.347, 95% CI = 1.038–1.748), dominant (DD+ID vs. II: p = 0.002; OR = 1.195, 95% CI = 1.070–1.334), and recessive (DD vs. ID+II: p = 0.023; OR = 1.338, 95% CI = 1.042–1.718) genetic models. Subgroup analysis stratified by Asian ethnicity revealed significant risk of SLE in allelic (D vs. I: p = 0.045; OR = 1.238, 95% CI = 1.005–1.525) and marginal risk in dominant (DD+ID vs. II: p = 0.056; OR = 1.192, 95% CI = 0.995–1.428) models; whereas, no association was observed for Caucasian and African population. Publication bias was absent. In conclusion, ACE I/D polymorphism has significant role in overall SLE risk and it can be exploited as a prognostic marker for early SLE predisposition.

An Extensive Study of the Functional Polymorphisms of Kinin-Kallikrein System in Rheumatoid Arthritis Susceptibility

Objectives

This study aims to examine the following functional polymorphisms in rheumatoid arthritis (RA) susceptibility: (i) the 587C>T of kininogen gene, (ii) the 287 bp Alu repeat insertion of angiotensin converting enzyme gene, (iii) the 9 bp insertion of bradykinin receptor 2 gene, (iv) the -58T>C of bradykinin receptor 2 gene, and (v) the -699G>C of bradykinin receptor 1 gene.

Patients and methods

The study included 136 RA patients (27 males; 109 females; mean age 60.8 years; range 39 to 75 years) and 149 ethnic matching controls (30 males, 119 females; mean age 56.2 years; range 35 to 78 years). Polymerase chain reaction coupled with restriction assay was performed for 587C>T, -58T>C, and -699G>C.

Results

Rheumatoid arthritis patients and controls carried the wild type allele of 587C>T; therefore, produced the high molecular weight kininogen. No significant difference was observed in genotype or allele distribution of the studied functional polymorphisms between RA patients and controls.

Conclusion

Kinin-kallikrein system related genes might not be major RA susceptibility loci.

Association of angiotensin-converting enzyme insertion/deletion polymorphism with susceptibility to systemic lupus erythematosus: a meta-analysis

BACKGROUND

The aim of this study was to determine whether the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) gene polymorphism confers susceptibility to systemic lupus erythematosus (SLE)/lupus nephritis (LN).

METHODS

A meta-analysis was conducted on the association between the ACE I/D polymorphism and SLE/LN (when available) using: (i) the allelic contrast; (ii) the recessive; (iii) the dominant; and (iv) the additive models.

RESULTS

A total of 27 relevant comparisons meeting the inclusion criteria were identified, involving 2718 SLE patients and 3655 controls. Meta-analysis showed a significant association between SLE and the allele D in overall populations (odds ratio [OR] = 1.25, 95% CI: 1.07-1.48, P = 0.004). Stratification by ethnicity indicated a strong association between the allele D and SLE in Asians (OR = 1.36, 95% CI: 1.05-1.75, P = 0.019). Meta-analysis also showed a significant association between SLE and the DD genotype in overall populations (additive model) (OR = 1.38, 95% CI: 1.05-1.83, P = 0.022). In addition, we found significant associations between the recessive model and SLE in overall populations, Asians and Europeans (OR = 1.44, 95% CI: 1.11-1.88, P = 0.007; OR = 1.69, 95% CI: 1.07-2.68, P = 0.024; and OR = 1.31, 95% CI: 1.06-1.62, P = 0.013, respectively). With respect to the association between ACE I/D gene polymorphism and LN risk, there was no significant association in either the overall populations or subpopulations.

CONCLUSION

The present study might suggest that ACE I/D polymorphism may be a genetic molecular marker to predict SLE, while this polymorphism may not correlate with LN susceptibility.

Angiotensin type 1 receptor A1166C polymorphism and systemic lupus erythematosus: correlation with cellular immunity and oxidative stress markers

Angiotensin II, one of the rennin–angiotensin system components, is important in the cardiovascular hemodynamic and plays an important role in the development of cardiovascular disease in systemic lupus erythematosus (SLE) patients. The angiotensin II, through interaction with angiotensin II type 1 receptor (AGTR1), promotes proliferation, inflammation and fibrosis. The single nucleotide polymorphism of the AGTR1 (dbSNP: rs5186) gene can be associated with development and progression of SLE disease. The aims of this study were to compare the frequency of AGTR1 rs5186 in SLE patients with healthy individuals and to evaluate possible association between AGTR1 A1166C gene polymorphism and serum level of lipids, neopterin and malondialdehyde in SLE patients from a population of West Iran. One hundred SLE patients and 98 healthy subjects were studied. The AGTR1 A1166C polymorphism was detected by polymerase chain reaction– restriction fragment length polymorphism method and the serum lipid profile was obtained by enzymatic method. Neopterin and malondialdehyde were detected using high-performance liquid chromatography. We did not detect significant association between AGTR1 A1166C polymorphism and the risk of SLE. The levels of triglyceride (225 ± 118 mg/dl), neopterin (30 ± 24 nmol/l) and malondialdehyde (25 ± 9.6 nmol/l) in SLE patients were significantly higher than those in control subjects (139 ± 56 mg/dl, p = 0.03, 6.4 ± 2, p = 0.03, 9.4 ± 2.5 nmol/l, p = 0.01, respectively). Individuals with AGTR1 AC + CC genotype had higher levels of total cholesterol and malondialdehyde compared with those with AGTR1 AA genotype. SLE patients with either AGTR1 AA or AGTR1AC + CC genotype had significantly higher malondialdehyde or neopterin levels compared with the corresponding control subjects. In conclusion, although the present study did not find any association between AGTR1 A1166C polymorphism and the risk of SLE, the presence of this polymorphism was associated with higher levels of malondialdehyde and higher concentration of neopterin in patients.

Angiotensin-converting enzyme insertion/deletion gene polymorphism in Egyptian children with systemic lupus erythematosus: a possible relation to proliferative nephritis

Introduction Angiotensin-converting enzyme (ACE) is crucial in the pathogenesis of systemic lupus erythematosus through angiotensin II which regulates vascular tone and endothelial functions. Objectives To study the frequency of ACE insertion/deletion (I/D) gene polymorphism in Egyptian children with systemic lupus erythematosus and its possible relation to the renal pathology in cases with lupus nephritis. Subjects and methods The frequency of ACE gene insertion/deletion polymorphism genotypes was determined in 78 Egyptian children with systemic lupus erythematosus and compared to a matched group of 140 healthy controls using polymerase chain reaction. Results The DD genotype of the ACE gene was higher in systemic lupus erythematosus patients when compared to controls ( P<0.0001; odds ratio (OR) 2.4; 95% confidence interval (CI) 1.7-3.3) and the D allele was more frequent than the I allele in systemic lupus erythematosus patients in comparison to controls ( P < 0.0001; OR = 2.2; 95% CI = (1.6-3.1). In the lupus nephritis group, the DD genotype was significantly higher in those with proliferative lupus nephritis when compared to those with non-proliferative lupus nephritis ( P = 0.02; OR = 1.45; 95% CI = 1.4-1.6). Also, patients with proliferative lupus nephritis showed a higher frequency of the D allele ( P < 0.001; OR = 1.98; 95% CI = 1.3-2.9). Conclusion The D allele and DD genotype of the ACE gene appear to be a risk factor for the susceptibility of systemic lupus erythematosus and occurrence of proliferative nephritis in Egyptian children.

Polymorphisms of the renin-angiotensin system genes in Brazilian patients with lupus nephropathy

Genetic polymorphisms of the renin-angiotensin system (RAS) has been associated with cardiovascular events and the progression of nephropathy in several diseases. The objective of this study was to evaluate a possible association of the genetic polymorphisms of RAS with the development and/or progression of lupus nephritis in a Brazilian population. Seventy-five SLE patients with lupus nephropathy (LN group) were compared to 72 SLE patients without LN (SLE group) and 65 healthy individuals (CONTROL group), of sex and ethnic matched, in a Brazilian population sample. Mean global follow-up was 9 + 6 years for lupus without nephropathy and 11 + 7 years for lupus nephropathy. Following the extraction of genomic DNA from the leukocytes in the peripheral blood, angiotensin converting enzyme (ACE I/D), angiotensinogen (AGT M235T) and angiotensin II type 1 receptor (AGTR1 A1166C) genotypes were determined by the polymerase chain reaction.

No significant difference of ACE, AGT and AGTR1 genotypes distribution between groups was observed in this study. There was no significant association between the variables of the RAS genotypes and the presence of hypertension in SLE. However, an increased frequency of DD genotype (ACE I/D) was observed in SLE patients with LN who progressed to CRF compared to healthy controls (DD 60%, DI 26.7%, II 13.3% versus 27.7%, 60% and 12.3%, respectively; x2 = 6.299, P = 0.0429). In the population studied, there was no influence of the RAS genetic polymorphisms in the development of lupus nephropathy, but the progression to CRF was associated with ACE DD polymorphism.

The renin-angiotensin system in lupus: physiology, genes and practice, in animals and humans

Although multiple studies suggest a potential role for angiotensin II in inflammation, most were performed either in vitro or in animals with non-immune-complex-mediated diseases. Extrapolation of these findings to humans, particularly patients with lupus, which involves multiple immunoregulatory pathways, is unclear. In autoimmune-prone MRL/lpr mice, angiotensin-converting-enzyme (ACE) inhibition improved survival although to a lesser degree than cyclophosphamide and diminished the glomerular histopathologic damage, proteinuria, lymphoid hyperplasia, dermatitis, and hypergammaglobulinemia, with a reduction in TGF-beta1 and beta 2 expression in the kidneys and renal chemokine mRNA expression. Spleen levels of IL-4 and IL-10 were also reduced. Uncontrolled studies in patients with treatment-refractory lupus nephritis showed a significant reduction in proteinuria with ACE-inhibitors and Angiotensin receptor blockers treatment. The ‘masking’ effect of ACE-inhibitors should be taken into consideration, as an exacerbation of lupus nephritis may be missed when estimated by the magnitude of proteinuria, which is decreased by these treatments. No single ACE genotype was consistently associated with subsets of SLE patients. In retrospective analyses, ACE-inhibitor use predicted a favourable outcome in 94 cases of pauci-immune vasculitis. The attenuating effect of angiotensin II inhibitors on the progression of chronic renal disease is well recognized. The data on the role of this intervention in lupus is limited.

Distribution of human leukocyte antigen alleles in systemic lupus erythematosus patients with angiotensin converting enzyme insertion/deletion polymorphism

Systemic Lupus Erythematosus is one of the classic examples of autoimmune diseases among human beings and is a rare disease in Pakistani population. Clinically it is a quite diverse and complicated autoimmune disease in a sense that it involves multiple organs of the body and mimics with other diseases as well. This study focused on the distribution of HLA alleles in SLE patients with ACE I/D Polymorphism. A total of 122 individuals were enrolled in this study, 61 were the SLE patients who fulfilled revised ACR criteria and 61 were the healthy controls. Mean age of SLE patients at diagnosis was 30.35 ± 1.687 years (Range: 12-68 years). ACE gene I/D polymorphism was performed by nested PCR and DNA based HLA typing technique was used. ACE gene I/D polymorphism of Intron16 was studied and found to be involved in the activity of SLE. There is high frequency of HLA-A*01, HLA-B*40, HLA-DRB1*01 alleles in SLE patients with ACE DD genotype. The distribution of HLA-A, -B, -DRB1 alleles was analyzed in SLE patients with various disease phenotypes. HLA-A*01 and HLA-B*40 was the most common allele found in SLE patients with the involvement of skin. HLA-A*01, -A*03, HLA-B*13 and -B*46 were common in SLE patients with arthritis while HLA-A*26 and -A*69 were commonly found in Lupus nephritis cases. SLE patients involving both skin and kidney had an allele HLA-DRB1*01 common in them.

Association between the LCE3C_LCE3B deletion polymorphism and susceptibility to psoriasis: a meta-analysis of published studies

OBJECTIVE

To determine whether a deletion comprising the LCE3C and LCE3B genes (LCE3C_LCE3B-del) confers susceptibility to psoriasis.

METHODS

A meta-analysis was conducted to assess the association between the LCE3C_LCE3B-del polymorphism and psoriasis.

RESULTS

A total of 12,196 patients with psoriasis and 13,092 controls from 19 comparative studies were included in this meta-analysis. The meta-analysis showed a significant association between psoriasis and the LCE3C_LCE3B-del allele (odds ratio [OR], 1.220; 95% confidence interval [CI], 1.152-1.292; p<1.0×10(-9)). Stratification by ethnicity indicated an association between the LCE3C_LCE3B-del allele and psoriasis in Europeans and Asians (OR, 1.213; 95% CI, 1.130-1.302; p=8.0×10(-9) and OR, 1.260; 95% CI, 1.135-1.398; p=1.4×10(-6), respectively). Analysis using a recessive model, dominant model, and homozygote contrast showed the same pattern for the LCE3C_LCE3B-del allele. The analysis performed in a single Tunisian study showed no association between the LCE3C_LCE3B-del allele and psoriasis. Meta-analysis of the LCE3C_LCE3B-del allele showed no association between psoriatic arthritis and the LCE3C_LCE3B-del polymorphism (OR, 1.087; 95% CI, 0.870-1.359; p=0.464).

CONCLUSION

Our meta-analysis demonstrates a significant association between psoriasis and the LCE3C_LCE3B-del polymorphism in Europeans and Asians, but no association with psoriatic arthritis.

Relationship between angiotensin-converting enzyme insertion/deletion gene polymorphism and systemic lupus erythematosus/lupus nephritis: a systematic review and metaanalysis

OBJECTIVE

Results from studies of the association between angiotensin-converting enzyme (ACE) insertion/deletion (I/D) gene polymorphism and systemic lupus erythematosus (SLE)/lupus nephritis (LN) are controversial. We performed this metaanalysis to evaluate the relationship between ACE I/D gene polymorphism and SLE/LN and to explore whether the ACE D allele or DD genotype could become a predictive marker for risk of SLE/LN.

METHODS

Association studies were identified from the databases of PubMed, Embase, Cochrane Library and CBM-disc (China Biological Medicine Database) as of May 1, 2011, and eligible investigations were synthesized using a metaanalysis method. Results were expressed with OR for dichotomous data, and 95% CI were calculated.

RESULTS

Sixteen investigations were identified for the analysis of association between ACE I/D gene polymorphism and SLE, consisting of 1959 patients with SLE and 2078 controls. In the overall populations, there was a marked association between D allele or DD genotype and SLE susceptibility (D: OR 1.29, 95% CI 1.04-1.58, p = 0.02; DD: OR 1.60, 95% CI 1.17-2.19, p = 0.003), and DD homozygous was associated with LN risk (OR 2.78, 95% CI 1.26-6.11, p = 0.01). In the subgroup analysis, DD genotype associated with SLE risk was observed in Asians; no other association was found in Asians, whites, Africans, and Brazilians.

CONCLUSION

D allele and DD homozygous are significant genetic molecular markers to predict SLE susceptibility, and DD genotype is a valuable marker to predict the LN risk. More investigations are required to clarify the association of the D allele or DD homozygous with SLE/LN susceptibility.

Angiotensin-converting enzyme (ACE) serum levels and gene polymorphism in Egyptian patients with systemic lupus erythematosus

Objectives: to investigate the association of angiotensin-converting enzyme (ACE) gene polymorphism and serum ACE level among Egyptian SLE patients and its relation to disease activity parameters. Subjects and methods: we enrolled 50 Egyptian female systemic lupus erythematosus (SLE) patients and 29 healthy controls. Measurement of serum ACE level was done using ELISA, and the ACE genotype was determined by polymerase chain reaction using genomic DNA from peripheral blood. Results: a significant difference was found in ACE genotypes between SLE patients and controls (χ2 = 7.84, p = 0.02). The frequency of ACE DD versus (DI and II) genotypes was significantly higher in SLE patients compared with controls (χ2 = 5.57, p = 0.018 and OR for risk of SLE was 3.1 with 95% confidence interval: 1.198.06). Mean serum ACE level was significantly higher in the SLE group compared with controls ( p = 0.006). Subjects with DD genotype had a significantly higher mean level than those with DI ( p = 0.015) and II genotypes ( p = 0.02). Lupus nephritis patients had a significantly higher frequency of DD versus DI and II genotypes compared with lupus patients without nephritis (Fisher's exact test, p = 0.025) and controls (χ 2 =8.74, p = 0.003). SLE patients with vasculopathy had a significantly higher frequency of DD versus DI/II genotypes compared with SLE patients without vasculopathy (Fisher's exact test, p = 0.04) and controls (χ2 = 9.84 and p = 0.002). Mean serum ACE level was significantly higher in the lupus nephritis and SLE patients with vasculopathy compared with controls ( p = 0.008, p = 0.001, respectively). Significant positive correlations were found between serum ACE level and serum creatinine and 24 h proteinuria ( p = 0.03, 0.009, respectively). SLE patients with DD genotype had a statistically significant higher mean SLEDAI score than those with (DI/II) genotypes ( p = 0.02). Significant positive correlation was found between serum ACE levels and SLEDAI scores ( p = 0.04). Conclusion: ACE genotype and subsequently serum ACE level could be associated with the disease activity of Egyptian SLE patients; in addition, ACE deletion polymorphism might be used as one of the predictive factors for the activity of SLE. Further studies on a larger number of patients should be done to determine the exact prevalence of ACE gene polymorphism among Egyptian SLE patients.

Blood pressure and renal hemodynamic responses to acute angiotensin II infusion are enhanced in a female mouse model of systemic lupus erythematosus

Inflammation and immune system dysfunction contributes to the development of cardiovascular and renal disease. Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disorder that carries a high risk for both renal and cardiovascular disease. While hemodynamic changes that may contribute to increased cardiovascular risk have been reported in humans and animal models of SLE, renal hemodynamics have not been widely studied. The renin-angiotensin system (RAS) plays a central role in renal hemodynamic control, and although RAS blockade is a common therapeutic strategy, the role of RAS in hemodynamic function during SLE is not clear. This study tested whether mean arterial pressure (MAP) and renal hemodynamic responses to acute infusions of ANG II in anesthetized animals were enhanced in an established female mouse model of SLE (NZBWF1). Baseline MAP was not different between anesthetized SLE and control (NZWLacJ) mice, while renal blood flow (RBF) was significantly lower in mice with SLE. SLE mice exhibited an enhanced pressor response and greater reduction in RBF after ANG II infusion. An acute infusion of the ANG II receptor blocker losartan increased RBF in control mice but not in mice with SLE. Renin and ANG II type 1 receptor expression was significantly lower, and ANG II type 2 receptor expression was increased in the renal cortex from SLE mice compared with controls. These data suggest that there are fewer ANG II receptors in the kidneys from mice with SLE but that the existing receptors exhibit an enhanced sensitivity to ANG II.

Association of the genetic polymorphisms of the ACE gene and the eNOS gene with lupus nephropathy in northern Chinese population

BACKGROUND

It has been reported that some single nucleotide polymorphisms (SNPs) of the angiotensin converting enzyme (ACE) gene and the endothelial nitric oxide synthase (eNOS) gene are associated with the development of systemic lupus erythematosus (SLE) and the progression of nephropathy. The aim of this study was to evaluate the possible association between six SNPs (A-5466C, T-3892C, A-240T, C1237T, G2215A and A2350G) of the ACE gene and two SNPs (T-786C and G894T) of the eNOS gene with lupus nephropathy in a northern Chinese population.

METHODS

In this study, 225 patients with lupus nephropathy were compared to 232 healthy controls, matched by gender, age and ethnicity. Following the extraction of genomic DNA from the leukocytes in the peripheral blood, the genotypes of the eight selected SNPs were determined by the method of PCR-RFLP; the haplotypes were inferred using PHASE 2.1. The associations between the SNPs and the risk of lupus nephropathy were analyzed using Chi-square test and Logistic regression with SPSS13.0 software.

RESULTS

Statistically significant differences of the allele frequency distribution of three SNPs (A-5466C, A2350G and G894T) were observed between cases and controls (P<0.05). Among the 53 haplotypes identified, the frequencies of five haplotypes (CTTCGA, ACTTAA, ACATGG, ACACGG and ATTCGA) were significantly different between cases and controls (P<0.05).

CONCLUSIONS

Our study indicated an association between the risk of lupus nephropathy and the sequence variations of both the ACE gene and the eNOS gene, which may play an important role in the pathogenesis of lupus nephropathy in the northern Chinese population. Further studies are warranted to validate our findings.

Association of angiotensin converting enzyme gene insertion/deletion polymorphism with lung cancer in Turkey

Angiotensin-converting enzyme (ACE) plays an important role in the physiological control of blood pressure and inflammation. We investigated an insertion/deletion (I/D) polymorphism of the gene for ACE in relation to cardiovascular, cerebrovascular, neurodegenerative, and inflammatory diseases. The purpose of the present study was to investigate a possible association between lung cancer and insertion/deletion polymorphism of the ACE gene. A total of 125 patients with lung cancer and 165 control subjects were enrolled in the present study. ACE I/D genotypes were determined by polymerase chain reaction. Allelic frequencies and genotype distribution of the ACE I/D polymorphism in the patient group were significantly different from control subjects (ACE II genotype 29.6 vs. 17.6%, P = 0.011; ACE I allele 49.6 vs. 39.4%, P =0.009). Our data suggest that the ACE I/D polymorphism could be a risk factor for patients with lung cancer.

The pathophysiology of hypertension in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disorder that predominantly affects women during their reproductive years. Although SLE can affect any organ system, the kidneys are prominently involved in the form of immune complex glomerulonephritis. In addition, in women with SLE, risk for the development of cardiovascular disease is dramatically increased. Hypertension is a major risk factor for cardiovascular disease and is highly prevalent in women with SLE. Nevertheless, there has been little exploration of the pathophysiological mechanisms that promote SLE hypertension. This review discusses the role of several mechanisms, with an emphasis on the kidney, in SLE hypertension. These mechanisms include the renin-angiotensin system, endothelin, oxidative stress, sex steroids, metabolic changes, peroxisome proliferator-activated receptor-gamma, and, perhaps most importantly, chronic inflammation and cytokines. Growing evidence suggests a link between chronic inflammation and hypertension. Therefore, elucidation of mechanisms that promote SLE hypertension may be of significant value not only for patients with SLE, but also for a better understanding of the basis for essential hypertension.

An alternative method for genotyping of the ACE I/D polymorphism

The mistyping of the angiotensin I-converting enzyme insertion/deletion (ACE I/D) has been well documented, and new methods have been suggested here to improve the genotyping efficiency. Buccal cell samples were collected from 157 young Caucasians, and genotyped using previously known and newly developed PCR amplification genotyping techniques, as well as PCR-RFLP tests for three single nucleotide polymorphisms (rs4327, rs4341 and rs4343). Inconsistent genotyping results were found when using only the PCR amplification genotyping techniques across repeated attempts (8% to 45%), however, individual SNP genotyping was highly consistent (100%). Two SNPs (rs4341 and rs4343) were in complete LD and SNP rs4327 was in high LD with the ACE I/D. The ACE I/D was in HW equilibrium in the portion of the population with consistent genotyping results, whereas the three SNPs were not in HW equilibrium. The mistyping of ACE I/D by only PCR amplification can be improved using alternative methods.

Genetics of Human Lupus Nephritis

Systemic lupus erythematosus (SLE) is a prototypic systemic autoimmune disease in which glomerulonephritis represents one of the most severe clinical presentations. Numerous linkage and association studies, as well as the analysis of murine models, have provided ample evidence for a genetic basis for SLE. Genetic susceptibility to SLE results from the combined actions of multiple alleles, each of them conferring a modest incremental risk. SLE susceptibility genes have been identified in 3 major pathways: apoptosis, lymphocyte activation, and clearance of immune complexes and/or apoptotic debris. There also now is evidence that, within SLE patients, renal end-organ targeting also has a genetic basis, which can be divided into 2 branches. There is evidence that susceptibility alleles that are associated with a greater disease severity also are associated with lupus nephritis. There also is evidence for a set of kidney-specific genes that are likely to amplify or to sensitize to the autoimmune pathology.

Angiotensin-converting enzyme gene polymorphism and allele frequencies in the lebanese population: prevalence and review of the literature

We studied the distribution of the D/D, I/D, and I/I genotypes of the angiotensin-converting enzyme (ACE) in a sample of healthy Lebanese individuals to assess their prevalence and compare them with other populations. ACE genotypes were determined using the Cardiovascular Disease (CVD) StripAssay, which is based on a Polymerase Chain Reaction-Reverse hybridization technique. DNA from 133 unrelated healthy donors from our HLA-bank was used. The prevalence of D/D, I/D, and I/I genotypes was found to be 39.1, 45.1, and 15.8% respectively, with D and I allelic frequency of 61.7 and 38.3%, respectively. The sampled Lebanese population showed ACE genotypic distributions similar to Caucasians; however, with tendency towards harboring high D allele frequency together with a low I allele frequency just like the Spanish population. This first report from Lebanon will serve as a baseline statistical data for future investigations of the prevalence of ACE genotypes in association with various clinical entities notably cardiovascular diseases. The medical literature was also reviewed in this context.

Glutathione S-transferase M1 and GST T1 genetic polymorphisms and Raynaud’s phenomenon in French vinyl chloride monomer-exposed workers

Occupational vinyl chloride monomer (VCM) exposure can induce Raynaud's phenomenon (RP). However, not all VCM workers developed RP, which suggests an underlying genetic susceptibility. Genetic polymorphisms of glutathione S-transferases (GSTs), involved in VCM metabolism, have been shown to influence certain VCM-related health effects. We have conducted a case-control study of 58 subjects with RP along with 247 subjects without RP, from a population of 305 French workers exposed or formerly exposed to VCM, to assess any association between GST M1 and GST T1 gene polymorphisms, either separately or in combination, and the presence of RP. None of the GST M1 or GST T1 genotypes were significantly associated with the presence of RP among studied VCM workers. A combination of positive genotypes for both GST M1 and GST T1 was significantly associated with RP presence, compared to the other combinations of genotypes (OR=2.1, 95% CI=1.1-3.8). OR adjusted for age, smoking status, alcohol consumption and history of treated hypertension did not reach significance (OR=2.0, 95% CI=0.9-5.2). None of the GST M1 and GST T1 genotypes seem to contribute separately to the presence of RP, suggesting that they are not, when taken alone, a major determinant of interindividual variability for VCM-induced PR. However, the combination of both positive GST M1 and GST T1 genotypes appears to contribute slightly to susceptibility to RP in VCM-exposed subjects. Nevertheless, our study-the first to examine the role of a genetic component in the occurrence of RP secondary to occupational exposure to a chemical-corroborates the previous considerations that interaction between the genetic constitution and environmental factors is of importance in determining the health-adverse effects of VCM exposure.

Angiotensin-converting enzyme gene insertion/deletion polymorphism in Korean patients with systemic sclerosis

To determine whether angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism is associated with the development and clinical features of systemic sclerosis (SSc) in Korean, we studied seventy two Korean patients with SSc fulfilling the ACR preliminary classification criteria. The controls were 114 healthy, disease free Koreans. ACE I/D genotypes were determined by PCR method using oligonucleotides. Sixty eight patients (94.4%) were women and age at diagnosis was 43.5+/-12.6 yr old (mean+/-SD). Thirty nine patients (54.2%) had a diffuse type of SSc. There were no statistical differences in the frequencies of all ACE I/D genotypes and D allele between patients and controls, and neither between diffuse and limited types of SSc. ACE I/D gene polymorphism was not associated with the development of SSc in Korea. The investigation for the pathogenesis of SSc requires more studies about the role of other candidate genes such as endothelin, TGF-beta, nitric oxide, or angiotensin II receptor in addition to the ACE genes.

Genetics of systemic lupus erythematosus: how far have we come?

There are two primary mechanisms for studying the genetic forces at work in systemic lupus erythematosus (SLE). Several groups have collected large numbers of pedigrees in which multiple family members have SLE for use in linkage studies. These linkage studies serve to isolate areas of the genome in which susceptibility genes lie. Other groups have taken a more direct approach of investigating genes that might contribute to disease pathogenesis in sets of lupus subjects and matched controls. These association studies are accumulating in greater numbers as the technology to determine the genotype at a given locus becomes more accessible. This article discusses the results of both types of studies.

Renin-angiotensin system gene polymorphisms predict the progression to renal insufficiency among Asians with lupus nephritis

The renin-angiotensin system (RAS) is a strong candidate as a mediator for the development and progression of lupus nephritis (LN). We performed an ethnically stratified analysis of 642 systemic lupus erythematosus (SLE) patients to determine whether various functional RAS gene polymorphisms are associated with SLE renal outcomes. Patients were genotyped for two angiotensin-converting enzyme (ACE) gene polymorphisms: Alu insertion/deletion (I/D) and 23 949 (CT)(2/3), and for two angiotensinogen (Atg) gene polymorphisms: M235T and C-532T. Multivariate analyses demonstrated associations between the ACE I/D, ACE (CT)(2/3) and Atg C-532T functional polymorphisms and LN among Asians. In stratified analyses among LN cases according to high vs low glomerular filtration rate (GFR), associations remained significant for the ACE D (odds ratio (OR) 5.9, P=0.001) and (CT)(2) (OR 6.2, P=0.001) alleles among Asian subjects with low GFR. Lastly, we found allelic dose-dependent associations between the ACE I/D (P=0.003), ACE (CT)(2/3) (P=0.005) and Atg M235T (P=0.04) polymorphisms, and GFR analyzed as a continuous variable among Asians. These findings suggest a significant role for ACE and Atg gene sequence variation and severity of LN among Asians with SLE.