Role of the deletion of polymorphism of the angiotensin converting enzyme gene in the progression and therapeutic responsiveness of IgA nephropathy

Evaluating direct amplification from viral transport medium for SARS-CoV-2 detection, strain typing, and angiotensin-converting enzyme genotyping and expression assays

OBJECTIVE

The aim of this study was to compare the performance of direct amplification of viral nucleic acid from transport medium to extracted nucleic acid for polymerase chain reaction (PCR), sequencing, and genotyping applications.

METHODS

XpressAmp lysate and extracted total nucleic acid from viral transport medium containing nasopharyngeal specimens were evaluated across different molecular applications to determine performance characteristics.

RESULTS

SARS-CoV-2 quantitative PCR and angiotensin-converting enzyme (ACE) genotyping assays worked well with XpressAmp lysate, almost equal with or better than extracted nucleic acid in some specimens. However, XpressAmp completely failed to perform in next-generation sequencing for strain typing. Both protocols failed to detect ACE2 expression in viral transport medium.

CONCLUSION

Direct amplification of viral nucleic acid from viral transport medium containing nasopharyngeal specimen works well for molecular assays with low thresholds of quality; however, it does have limitations with assays that require high quality nucleic acid for input. Use of the XpressAmp protocol significantly improves turnaround time and allows for easy ramp-up of PCR and genotyping assays.

Investigation of Serum Angiotensin-Converting Enzyme (ACE) Concentration and ACE Gene Polymorphism in Patients With SARS-CoV-2 Pneumonia Admitted to the Emergency Department

Background This study seeks to investigate the distribution of the angiotensin-converting enzyme (ACE) gene polymorphism and serum levels in patients with viral pneumonia and predict which polymorphism will lead to severe progression of the disease. Methodology The serum ACE levels and ACE gene polymorphisms were successfully evaluated with respect to subsequent viral pneumonia using records of 100 patients with viral pneumonia and 100 healthy controls. Results ACE serum concentration was statistically significantly elevated. ACE serum concentration with a cut-off value of ≥5,256.05 pg/mL had 85.3% sensitivity and 83.2% selectivity. In addition, patients with ACE genotype D/D were 0.08 times more likely to manifest severe lung involvement than those with I/I, and patients with the I/D genotype were 0.02 times more likely than their counterparts with I/I. The computed tomography findings of the patients revealed that ACE serum concentration was significantly effective in discriminating between mild and moderate-to-severe lung involvement. No significant difference was observed between the blood parameters and ACE genotype distributions. Conclusions I/D polymorphism likely affects the expression of the ACE gene and/or the function of the angiotensin I converting enzyme. The D/D genotype is associated with vessel wall thickness and higher blood pressure. Strong evidence was found between D/D and I/D genotypes in the patient cohort concerning genotypes and ACE serum concentration. Further analysis showed that ACE serum levels were more elevated in the D/D genotype compared to the I/D genotype in the patient cohort.

Are angiotensin converting enzyme (ACE1/ACE2) gene variants associated with the clinical severity of COVID-19 pneumonia? A single-center cohort study

OBJECTIVE

The impact of the coronavirus disease 2019 (COVID-19) pandemic has been unceasingly ongoing worldwide. Recent bioinformatics analysis and epidemiologic studies have highlighted that the functional polymorphisms on the angiotensin converting enzyme (ACE) gene may have an impact on the clinical progress of COVID-19. In this study, we aimed to determine the impact of the ACE1 gene I/D polymorphism and ACE2 peptidase-2 domain variants on disease severity.

METHODS

Hundred patients with confirmed COVID-19 related pneumonia [50 patients with severe disease in intensive care unit (ICU) and 50 patients not in ICU] were compared on the basis of genetic and clinical characteristics. Genomic DNA was purified from peripheral blood lymphocytes with an automated QIA symphony DSP DNA Mini-Kit. The Sanger sequencing analysis was performed. The frequencies of ACE1 gene polymorphism and ACE2 PD variants were compared in patients hospitalized in ICU and those not in ICU. The Statistical Package for Social Sciences version 22.0 was used for statistical analysis.

RESULTS

The sequencing analysis of the ACE2 gene exon 1 and 2 revealed none of the polymorphisms investigated or any other variants in the present cohort. The frequencies of the ACE1 ID, DD, and II genotypes were 51%, 31%, and 18%, respectively. The frequency of the D allele was similar between the ICU and non-ICU groups (50.4% versus 49.6%). Older age and the presence of advanced stage radiologic abnormalities on admission were detected as independent predictors of ICU requirement.

CONCLUSION

No effect of any ACE1 gene polymorphism on predicting ICU requirement was detected. To the best of our knowledge, this is the first study investigating the impact of ACE gene polymorphisms on clinical severity of COVID-19 in a Turkish cohort.

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.

Comparative efficacy of different renin angiotensin system blockade therapies in patients with IgA nephropathy: a Bayesian network meta-analysis of 17 RCTs

Background

IgA nephropathy (IgAN) is still one of the most prevalent forms of primary glomerulonephritis globally. However, no guidelines have clearly indicated which kinds of renin angiotensin system blockade therapies (ACEIs or ARBs or their combination) in patients with IgAN result in a greater reduction in proteinuria and a better preservation of kidney function. Thus, we conducted a Bayesian network analysis to evaluate the relative effects of these three therapy regimens in patients with IgAN.

Methods

The protocol was registered in PROSPERO with ID CRD42017073726. We comprehensively searched the PubMed, the Cochrane Library, Embase, China Biology Medicine disc, WanFang and CNKI databases for studies published since 1993 as well as some grey literature according to PICOS strategies. Pairwise meta-analysis and Bayesian network analysis were conducted to evaluate the effect of different regimens.

Results

Seventeen randomized controlled trials (RCTs) involving 1,006 patients were analyzed. Co-administration of ACEIs and ARBs had the highest probability (92%) of being the most effective therapy for reducing proteinuria and blood pressure, but ACEIs would be the most appropriate choice for protecting kidney function in IgAN.

Conclusion

The combination of ACEIs and ARBs seems to have a significantly better antiproteinuric effect and a greater reduction of blood pressure than ACEI or ARB monotherapy in IgAN. ACEIs appear to be a more renoprotective therapy regimen among three therapies.

Frequency of alleles associated with celiac disease in patients with autoimmune thyroid disease

ABSTRACT Objective To determine the frequency of Human leukocyte antigen alleles and to verify the association of the presence of these alleles with symptoms and other diseases related to celiac disease in patients with autoimmune thyroid diseases. Methods A questionnaire on the symptoms and diseases associated with celiac disease was applied. Genomic deoxyribonucleic acid was extracted by collecting cells from the oral mucosa. The alleles (DQA1*0501; DQB1*0201; DRB1*04) were identified by means of the polymerase chain reaction. Results A total of 110 patients with autoimmune thyroid diseases participated in this study. It was observed that 66.4% of the individuals carried at least one of the alleles assessed and that 58.2% of the individuals were positive for at least one of the DQ2 alleles (DQA1*0501; DQB1*0201) and out of these 18.2% were positive for both DQ2 alleles (DQA1*0501; DQB1*0201). With regard to DQ8 (DRB1*04), 21.8% of the studied population was positive for this allele and 3.6% was positive for both DQ2 (DQA1*0501; DQB1*0201) and DQ8 (DRB1*04). A significant association was found between the presence of the DRB1*04 allele and gastrointestinal symptoms (p=0.02). A significant association of the DRB1*04 allele with type 1 diabetes mellitus (p=0.02) was observed. Conclusion The genetic profiles most commonly associated with celiac disease, such as DQ2 (DQA1*0501; DQB1*0201) and DQ8 (DRB1*04) were around 20.0% prevalent in the studied population. These are risk haplotypes for celiac disease especially when symptoms and diseases related to celiac disease are present. Therefore, it is important to screen patients to investigate a potential diagnosis for celiac disease.

Serologic and Histologic Predictors of Long-Term Renal Outcome in Biopsy-Confirmed IgA Nephropathy (Haas Classification): An Observational Study

Background and objective: The Haas classification of IgA nephropathy should be validated for Asian populations. More detailed and newer predictions regarding renal outcome of IgA nephropathy remains mandatory. Materials: We conducted a retrospective cohort study between January 2003 and December 2013. Clinical, Pathological, and laboratory data were all collected via available medical records. A Mann–Whitney U test was used for continuous variables and the Chi-square test was implemented for categorical variables. A Kaplan–Meier curve was put in place in order to determine patient survival and renal survival. The Youden index and Cox proportional hazard regression were used to investigate the possible factors for renal survival and predictive power. Results: All 272 renal biopsy-confirmed IgAN patients were enrolled for further studies. The univariate analysis showed that risk factors for poor renal outcome included stage 4–5 of Haas classification (HR = 3.67, p < 0.001), a poor baseline renal function (HR = 1.02 and p < 0.001 for higher BUN; HR = 1.14 and p < 0.001 for higher serum creatinine; HR = 0.95, p < 0.001 for higher eGFR), IgG ≤ 907 (HR = 2.29, p = 0.003), C3 ≤ 79.7 (HR = 2.76, p = 0.002), a higher C4 (HR = 1.02, p = 0.026), neutrophil-to-lymphocyte ratio > 2.75 (HR = 2.92, p < 0.001), and a platelet-to-lymphocyte ratio ≥ 16.06 (HR = 2.02, p = 0.012). A routine-checked markers, such as neutrophil-to-lymphocyte ratio and platelet-to-lymphocyte ratio, in order to predict the renal outcome, is recommended. Conclusions: This is the first study to demonstrate that Haas classification is also useful for establishing predictive values in Asian groups. A lower serum IgG (≤907 mg/dL) and serum C3 (≤79.7 mg/dL) were both risk factors for poor renal outcome. Additionally, this is the first study to reveal that serum C4 levels, an NLR > 2.75 and a PLR > 16.06, S could suggest poor renal outcome.

ACE Insertion/Deletion Polymorphism (rs4646994) Is Associated With the Increased Risk of Multiple Myeloma

Introduction: The insertion (I allele) deletion (D allele) polymorphism of ACE gene (rs4646994) may influence the etiopathogenesis of multiple myeloma (MM). ACE gene is expressed in bone marrow cells and encodes angiotensin converting enzyme (ACE). It converts angiotensin I to active peptide angiotensin II, which stimulates proliferation of hematopoietic stem cells. This suggests possible association of ACE I/D gene polymorphism with MM. The aim of our study was to check possible impact of this polymorphism on risk of development and outcome of MM, as well as, sensitivity to bortezomib in cell cultures derived from MM patients.

Objects and Methods: Genomic DNA from 98 newly diagnosed MM patients and 100 healthy blood donors were analyzed by PCR method. Chromosomal aberrations were detected by use of cIg-FISH. In a subgroup of 40 MM patients nucleated bone marrow cells were treated with bortezomib in vitro.

Results: The Hardy-Weinberg equilibrium test showed that genotypic frequencies diverged significantly from the equilibrium. The differences between I and D allele frequencies in control and study population were significant (p = 0.046). We observed the association between DD genotype and more than 2-fold risk of MM - OR = 2.69; p < 0.0001. We did not detect any significant differences among studied genotypes regarding clinical and laboratory parameters. Moreover, we did not observe the association between survival of MM patients and I/D genotypes. Bortezomib increased number of apoptotic and necrotic cells, but the only statistically significant differences were observed in the number of viable cells at 1 nM between ID and DD genotypes (p = 0.026).

Conclusion: Presented results confirmed the significant relationship between ACE (I/D) polymorphism and risk of MM development. We did not observe the association of ACE I/D polymorphism with disease outcome and bortezomib in vitro sensitivity.

Angiotensin-converting enzyme insertion/deletion (rs106180) and angiotensin type 1 receptor A1166 C (rs106165) genotypes and psoriasis: Correlation with cellular immunity, lipid profile, and oxidative stress markers

Psoriasis is a chronic inflammatory skin condition and angiotensin-converting enzyme (ACE) is a key circulating enzyme converting angiotensin (Ang) I to the vasoactive peptide Ang II. The exact role of ACE insertion (I)/deletion (D) polymorphism (rs106180) in psoriasis is not clear. We aimed to examine whether the ACE I/D and Ang II type 1 receptor (AT1R) A₁₁₆₆ C-polymorphisms (rs106165), lipid profile, and stress oxidative are associated with susceptibility to psoriasis. One hundred patients with psoriasis and 100 sex- and age-matched unrelated healthy controls were recruited for this case-control study. ACE I/D and AT1R A₁₁₆₆ C polymorphisms were identified by the polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism, respectively, malondialdehyde (MDA) was detected by the high-performance liquid chromatography, serum arylesterase (ARE) activity of paraoxonase and catalase activities were detected by the spectrophotometry, superoxide dismutase (SOD) activity and vascular adhesion protein (VAP)-1 were measured by ELISA. The presence of C allele of AT1R A₁₁₆₆ C and I allele of ACE considerably increased the risk of psoriasis by 6.42-fold (P < 0.001). The distribution of II-genotype of ACE was significantly higher in psoriasis patients than in control group and increased the risk of disease by 3.11-times (P = 0.023). The higher levels of MDA in patients and the higher activity of SOD, ARE, and CAT was observed in healthy controls with I/D+I/I-genotype of ACE I/D. This study for the first time demonstrated that the ACE I/D and AT1R A ₁₁₆₆ C genes polymorphisms robustly increases the risk of developing psoriasis in population from west of Iran. In addition, these individuals had significantly higher VAP-1 and MDA concentration and lower enzymatic and nonenzymatic antioxidant-status, suggesting that psoriatic patients carrying C allele of AT1R₁₁₆₆ polymorphism may be more susceptible to cardiovascular disease and myocardial infarction compared with A allele.

Primary IgA nephropathy: current challenges and future prospects

IgA nephropathy (IgAN) is the most common form of primary glomerulonephritis worldwide, exhibiting a variable clinical and pathological course and significantly contributing to the global burden of chronic kidney disease and end-stage renal disease. Current standards of care focus on optimization of antihypertensive and antiproteinuric therapies (typically renin- angiotensin system blockade) to reduce disease progression. Much recent attention has focused on whether additional immunosuppression confers better outcomes than supportive management alone, and indeed, several trials have demonstrated renoprotective effects following the use of oral corticosteroids. However, results have been inconsistent, and perceived benefits must be balanced against risks and adverse effects associated with generalized immunosuppression, as highlighted by the high-profile STOP-IgAN and TESTING clinical trials. Recent translational research in vitro and animal models of IgAN have generated greater insight into potential therapeutic targets for this complex autoimmune disease. Deeper understanding of the roles of the mucosal immune barrier, complement activation and deposition, T-cell dependent and independent mechanisms of B cell activation, and of the deposition and downstream inflammatory signaling pathways of nephritogenic polymeric IgA1 complexes (e.g., signaling of immune receptors via spleen tyrosine kinase) has formed the rationale for the development of novel agents and clinical trials of more targeted therapies. However, translating findings into clinical practice is challenging, with many immunopathological features of IgAN specific to humans. Recent comprehensive reviews outline current understanding of mechanisms of IgAN as well as ongoing and future clinical trials; it is not our aim to replicate this here. Instead, we take a mechanistic approach to current treatment strategies, outlining advantages and limitations of each before exploring ongoing research with potential translation into future targeted therapies for this complex disease.

Genetically increased angiotensin I-converting enzyme alters peripheral and renal vascular reactivity to angiotensin II and bradykinin in mice

Angiotensin I-converting enzyme (ACE) levels in humans are under strong genetic influence. Genetic variation in ACE has been linked to risk for and progression of cardiovascular and renal diseases. Causality has been documented in genetically modified mice, but the mechanisms underlying causality are not completely elucidated. To further document the vascular and renal consequences of a moderate genetic increase in ACE synthesis, we studied genetically modified mice carrying three copies of the ACE gene (three-copy mice) and littermate wild-type animals (two-copy mice). We investigated peripheral and renal vascular reactivity to angiotensin II and bradykinin in vivo by measuring blood pressure and renal blood flow after intravenous administration and also reactivity of isolated glomerular arterioles by following intracellular Ca2+ mobilization. Carrying three copies of the ACE gene potentiated the systemic and renal vascular responses to angiotensin II over the whole range of peptide concentration tested. Consistently, the response of isolated glomerular afferent arterioles to angiotensin II was enhanced in three-copy mice. In these mice, signaling pathways triggered by endothelial activation by bradykinin or carbachol in glomerular arterioles were also altered. Although the nitric oxide (NO) synthase (NOS)/NO pathway was not functional in arterioles of two-copy mice, in muscular efferent arterioles of three-copy mice NOS3 gene expression was induced and NO mediated the effect of bradykinin or carbachol. These data document new and unexpected vascular consequences of a genetic increase in ACE synthesis. Enhanced vasoconstrictor effect of angiotensin II may contribute to the risk for cardiovascular and renal diseases linked to genetically high ACE levels.

NEW & NOTEWORTHY A moderate genetic increase in angiotensin I-converting enzyme (ACE) in mice similar to the effect of the ACE gene D allele in humans unexpectedly potentiates the systemic and renal vasoconstrictor responses to angiotensin II. It also alters the endothelial signaling pathways triggered by bradykinin or carbachol in glomerular efferent arterioles.

A functional variant in NEPH3 gene confers high risk of renal failure in primary hematuric glomerulopathies. Evidence for predisposition to microalbuminuria in the general population

Background

Recent data emphasize that thin basement membrane nephropathy (TBMN) should not be viewed as a form of benign familial hematuria since chronic renal failure (CRF) and even end-stage renal disease (ESRD), is a possible development for a subset of patients on long-term follow-up, through the onset of focal and segmental glomerulosclerosis (FSGS). We hypothesize that genetic modifiers may explain this variability of symptoms.

Methods

We looked in silico for potentially deleterious functional SNPs, using very strict criteria, in all the genes significantly expressed in the slit diaphragm (SD). Two variants were genotyped in a cohort of well-studied adult TBMN patients from 19 Greek-Cypriot families, with a homogeneous genetic background. Patients were categorized as “Severe” or “Mild”, based on the presence or not of proteinuria, CRF and ESRD. A larger pooled cohort (HEMATURIA) of 524 patients, including IgA nephropathy patients, was used for verification. Additionally, three large general population cohorts [Framingham Heart Study (FHS), KORAF4 and SAPHIR] were used to investigate if the NEPH3-V353M variant has any renal effect in the general population.

Results and conclusions

Genotyping for two high-scored variants in 103 TBMN adult patients with founder mutations who were classified as mildly or severely affected, pointed to an association with variant NEPH3-V353M (filtrin). This promising result prompted testing in the larger pooled cohort (HEMATURIA), indicating an association of the 353M variant with disease severity under the dominant model (p = 3.0x10^-3, OR = 6.64 adjusting for gender/age; allelic association: p = 4.2x10^-3 adjusting for patients’ kinships). Subsequently, genotyping 6,531 subjects of the Framingham Heart Study (FHS) revealed an association of the homozygous 353M/M genotype with microalbuminuria (p = 1.0x10^-3). Two further general population cohorts, KORAF4 and SAPHIR confirmed the association, and a meta-analysis of all three cohorts (11,258 individuals) was highly significant (p = 1.3x10^-5, OR = 7.46). Functional studies showed that Neph3 homodimerization and Neph3-Nephrin heterodimerization are disturbed by variant 353M. Additionally, 353M was associated with differential activation of the unfolded protein response pathway, when overexpressed in stressed cultured undifferentiated podocyte cells, thus attesting to its functional significance. Genetics and functional studies support a “rare variant-strong effect” role for NEPH3-V353M, by exerting a negative modifier effect on primary glomerular hematuria. Additionally, genetics studies provide evidence for a role in predisposing homozygous subjects of the general population to micro-albuminuria.

The Genetic Determinants of Renal Impairment Following Cardiac Surgery

Cardiac surgery is frequently performed, and acute renal dysfunction is a common adverse event following this procedure. Cardiac surgery-related renal injury independently predicts longer hospital stays and greater rates of morbidity and mortality. Although much work has been completed toward better understanding of this phenomenon, the state of knowledge concerning surgery-related renal injury remains limited. Currently, there is no effective paradigm to identify patients who are at risk for this condition; the specific mechanisms of renal injury during surgery are incompletely understood; and few therapies exist to prevent or treat this phenomenon. To better understand this common clinical problem, recent research has focused on the importance of genetic variability within the physiological and patho-physiological systems that underlie renal dysfunction following cardiac surgery. Emphasizing the importance of using genetics to elucidate molecular mechanisms of this disease, this article reviews the current literature on genetic polymorphisms and post cardiac surgery-related renal dysfunction.

Novel Therapies of Diabetic Nephropathy

Diabetic nephropathy is currently the most common cause of end stage renal disease not only in the Western hemisphere but also in the developing nations. While the available therapeutic options remain not very effective, there is a strong ongoing effort to understand the pathogenesis better and develop more useful biomarkers. As the pathogenic mediators and signaling pathways get better defined, the scope of novel pharmaceutical agents to address such mediating factors as therapeutic targets is advancing. This review provides, in addition to a brief synopsis of currently used strategies, a comprehensive review of potential therapies that have been evolving in the past decade with a specific focus on the promising agents.

The Insertion/Deletion Polymorphism of Angiotensin I Converting Enzyme Gene is Associated With Ossification of the Posterior Longitudinal Ligament in the Korean Population

OBJECTIVE

To determine whether ACE insertion/deletion (I/D) polymorphism is associated with the ossification of the posterior longitudinal ligament (OPLL) of the spine in the Korean population.

METHODS

A case-control study was conducted to investigate the association between I/D polymorphism of the angiotensin I converting enzyme (peptidyl-dipeptidase A) 1 (ACE) gene and OPLL. The 95 OPLL patients and 274 control subjects were recruited. Polymerase chain reaction for the genotyping of ACE I/D polymorphism was performed. The difference between the OPLL patients and the control subjects was compared using the contingency χ(2) test and the logistic regression analysis. For statistical analysis, SPSS, SNPStats, SNPAnalyzer, and Helixtree programs were used.

RESULTS

The genotype and allele frequencies of ACE I/D polymorphism showed significant differences between the OPLL patients and the control subjects (genotype, p<0.001; allele, p=0.009). The frequencies of D/D genotype and D allele in the OPLL group were higher than those in the control group. In logistic regression analysis, ACE I/D polymorphism was associated with OPLL (dominant model; p=0.002; odd ratio, 2.20; 95% confidence interval, 1.33-3.65).

CONCLUSION

These results suggest that the deletion polymorphism of the ACE gene may be a risk factor for the development of OPLL in the Korean population.

Angiotensin-converting enzyme insertion/deletion polymorphism contributes high risk for chronic kidney disease in Asian male with hypertension--a meta-regression analysis of 98 observational studies

Background

Associations between angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphisms and chronic kidney disease (CKD) have been extensively studied, with most studies reporting that individuals with the D allele have a higher risk. Although some factors, such as ethnicity, may moderate the association between ACE I/D polymorphisms and CKD risk, gender-dependent effects on the CKD risk remain controversial.

Objectives

This study investigated the gender-dependent effects of ACE I/D polymorphisms on CKD risk.

Data sources

PubMed, the Cochrane library, and EMBASE were searched for studies published before January 2013.

Study eligibility criteria, participants, and interventions

Cross-sectional surveys and case–control studies analyzing ACE I/D polymorphisms and CKD were included. They were required to match the following criteria: age >18 years, absence of rare diseases, and Asian or Caucasian ethnicity.

Study appraisal and synthesis methods

The effect of carrying the D allele on CKD risk was assessed by meta-analysis and meta-regression using random-effects models.

Results

Ethnicity [odds ratio (OR): 1.24; 95% confidence interval (CI): 1.08–1.42] and hypertension (OR: 1.55; 95% CI: 1.04–2.32) had significant moderate effects on the association between ACE I/D polymorphisms and CKD risk, but they were not significant in the diabetic nephropathy subgroup. Males had higher OR for the association between ACE I/D polymorphisms and CKD risk than females in Asians but not Caucasians, regardless of adjustment for hypertension (p<0.05). In subgroup analyses, this result was significant in the nondiabetic nephropathy group. Compared with the I allele, the D allele had the highest risk (OR: 3.75; 95% CI: 1.84–7.65) for CKD in hypertensive Asian males.

Conclusions and implications of key findings

The ACE I/D polymorphisms may incur the highest risk for increasing CKD in hypertensive Asian males.

Distribution of performance-related gene polymorphisms (ACTN3 R577X and ACE ID) in different ethnic groups of the Indian Army

BACKGROUND

India has a heterogeneous geographical location with varying ethnic groups with distinct genetic pools. Polymorphisms R577X and insertion/deletion (I/D), occurring in α-actinin3 (ACTN3) and angiotensin converting enzyme (ACE) genes, respectively, are reportedly associated with sprint and endurance performance. The normative genetic background of a population provides the baseline genetic diversity of the population.

METHODS

We investigated the distribution of R577X and I/D polymorphisms in four Indian ethnic populations employed in the Indian Army that requires high levels of physical fitness. A total of 598 army subjects with four different ethnicities were recruited for the study: Rajputs, South Indians, Gorkhas, and Ladakhis. Genotyping was performed using polymerase chain reaction-restriction fragment length polymorphism followed by statistical analysis.

RESULTS

The present study reports for the first time the genotypic distribution of ACTN3 R577X polymorphism in four ethnic groups of the Indian population with no significant change in distribution of R and X alleles among these groups and their overall percentage bearing similarity with the Caucasian population. ACE I/D polymorphism showed significant differences between Rajputs and Gorkhas, Rajputs and Ladakhis, Gorkhas and South Indians, and South Indians and Ladakhis. Combined genotypic analysis showed the highest frequencies of ID+RX in all ethnic groups.

CONCLUSIONS

Our study reports the genetic predominance of ACE I allele in Gorkhas and I allele predominance in Ladakhis for the first time, thus suggesting that they could be better endurance performers. Both these ethnic groups evolved from the Mongolian race and hence could have similar genotypic distribution. This study provides a comparative account of the Indian normative genetic data in performance-related genes.

Renin-angiotensin system, hypertension, and chronic kidney disease: pharmacogenetic implications

About 80% of CKD (chronic kidney disease) patients are hypertensive, and kidney function and blood pressure are clearly related to both physiologic and pathologic conditions in a "vicious cycle". In this pathologic scenario, there is a renin-angiotensin system (RAS) hyperactivity associated to progression of renal damage. Current guidelines indicate as the first choice of antihypertensive intervention, the pharmacologic blockade of the RAS. Nonetheless, both response to treatment and renal protection have considerable inter-individual variability. The main aims of this review are to describe the genetic characteristics of RAS components and to identify the possible pharmacogenetic implications for RAS-blocker drugs in the hypertension-CKD scenario. To date, RAS polymorphisms have not been consistently associated to antihypertensive response and studies focusing on CKD are scarce. Nonetheless, pharmacogenetic studies for the RAS-blocker drugs could still be further explored, especially with new generation tools and focusing not only on the antihypertensive response, but also on renal protection as well.

Glu298Asp Endothelial Nitric Oxide Synthase Polymorphism Is a Risk Factor for Erectile Dysfunction in the Mexican Mestizo Population

Penile erection depends on the balanced action between antagonist vasoactive molecules such as nitric oxide (NO) and angiotensin. Endothelial nitric oxide synthase (eNOS) and angiotensin-converting enzyme (ACE) polymorphisms have been associated with endothelial dysfunction, which is described as a cause of erectile dysfunction (ED). Endothelial NOS and ACE are both regulators of vascular and corporal smooth muscle tone, which are connected by interaction between the NO-cyclic guanosine monophosphate pathway and the renin-angiotensin system. We analyzed the frequencies of 894 G/T (Glu298Asp) eNOS and ACE I/D polymorphisms in Mexican patients with ED (n=53) and in an age-matched control group (n=62). The populations analyzed were in Hardy Weinberg equilibrium. We found significant differences in allelic (chi2=4.42; P=.03) and genotypic frequencies (chi2=3.96; P=.04) between patients and controls for the 894 G/T eNOS polymorphism. Presence of the 894T allele in carriers increased the risk of ED (odds ratio [TT + GT versus GG] = 2.37; 95% confidence interval, 1.08 to 5.21; P=.02). Multiple logistic regression analysis showed that the Glu298Asp polymorphism was an independent factor for ED, as was diabetes mellitus, hypertension, cardiac disease, and cigarette smoking. No association was found between ACE I/D polymorphism and ED in the population studied. Therefore, our results suggest that Glu298Asp eNOS polymorphism plays a role as a genetic susceptibility factor for ED.

IgA nephropathy in India: what we do know

BACKGROUND

Even though IgA nephropathy (IgAN) is not the most common primary glomerulonephritis (GN) in India, the outcome of patients with IgAN in India is poor when compared with other parts of the world, which is a burden in itself.

METHODS

Basic and clinical research work in India on primary IgAN was systematically reviewed. Comparisons between data from India and those from other countries were made.

RESULTS

IgAN constitutes between 7% and 16% of most biopsy samples from India, bearing in mind these figures may represent only the tip of the iceberg. Nephrotic syndrome and renal failure seem to be common presenting features. The renal survival rates appear to be dismally low. DD genotype of angiotensin-1 converting enzyme (ACE) gene may predispose the individual to IgAN in Indian population. As might be expected, IgAN can recur posttransplant though the posttransplant course is indolent. There are no data on the treatment aspects of IgAN.

CONCLUSION

Low incidence but marked severity characterizes IgAN in India. It is apparent that IgAN seems to have a poor outcome in India. What we are unsure of is the reason behind it. In-depth basic studies and multicenter clinical trials are needed to address this bizarre pattern.

Association between ACE polymorphism and risk of IgA nephropathy: a meta-analysis

BACKGROUND

and objective: The effect of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism on risk or progression of immunoglobulin A nephropathy (IgAN) is still debated.Therefore, a meta-analysis was performed to evaluate the association of ACE gene polymorphism with IgAN in different ethnic groups.

METHOD

A predefined search strategy was performed to collect data from electronic databases.

RESULTS

Twenty articles were identified for the analysis of the relationship between ACE polymorphism and IgAN risk, including 11 in Asians and nine in Caucasians. There was a markedly positive association between the D allele or DD genotype and IgAN risk in Asians (OR = 1.27, p = 0.006; OR = 1.83, p < 0.0001). However, a link between D allele or DD genotype and IgAN risk was not found in Caucasians (OR = 1.04, p = 0.46; OR = 1.13, p = 0.12). Ten investigations were included for analysis of the association of ACE polymorphism with IgAN progression, including six in Asians and four in Caucasians. These data did not support a link between the ACE D allele or DD genotype and IgAN progression in Asians and Caucasians (Asians: D: OR = 1.03, p = 0.80; DD: OR = 1.43, p = 0.16; Caucasians: D: OR = 1.29, p = 0.22; DD: OR = 1.31, p = 0.17).

CONCLUSIONS

The D allele or DD genotype is associated with IgAN risk in Asian, but not in Caucasian populations; there was no significant association between the D allele or DD gene and IgAN progression for Asians and Caucasians.

Genetic polymorphisms related to the renin-angiotensin-aldosterone system and response to antihypertensive drugs

IMPORTANCE OF THE FIELD

Only 23 - 41% of hypertensive patients receiving antihypertensive drugs achieve adequate blood pressure control. Multiple physiological systems regulate blood pressure and variation in genes involved in these systems may account for enhanced or diminished blood pressure lowering response to antihypertensive therapy.

AREAS COVERED IN THIS REVIEW

We explored explanations for variation in blood pressure response to antihypertensive drugs by linking genetic polymorphisms in renin-angiotensin-aldosterone system (RAAS) genes to antihypertensive drug response on intermediate parameters (e.g., potassium excretion, aldosterone levels). A MEDLINE search (1966 - 2008) was performed to identify publications reporting effects of genetic polymorphisms in the RAAS on antihypertensive drug response with regard to intermediate parameters.

WHAT THE READER WILL GAIN

With regard to the ACE insertion/deletion and the angiotensinogen -217G/A polymorphism variation in blood pressure response could be explained by effects on intermediate parameters. However, most studies that were identified with our search varied in study design, population and outcome, which complicate adequate comparisons.

TAKE HOME MESSAGE

Little evidence is available that explains these pharmacogenetic interactions. In the future, a better understanding of these mechanisms should provide a more solid evidence base for the individualized hypertension treatment based on genetic variation.

Genetical, histological, and clinical characteristics of IgA-negative mesangioproliferative glomerulopathy

BACKGROUND

Mesangioproliferative glomerulopathy (MesPGN) is a well-defined pathohistological entity. However, the clinical characteristics and prognosis have not been fully established in patients without immunoglobulin (Ig)A (N-IgAN) in contrast to patients with IgA nephropathy (IgAN).

METHODS

A total of 837 consecutive patients underwent renal biopsies. Among them, 465 patients were diagnosed with MesPGN by light microscopy. With immunofluorescent study and electron microscopy (EM), 344 were diagnosed as having IgAN. Among the rest, 84 patients who had no immunofluorescence evidence of IgA and no deposits in EM were defined as N-IgAN. We compared the clinical characteristics, histological findings, and genotypes of the angiotensin-converting enzyme (ACE) gene and plasminogen activator inhibitor-1 gene between IgAN and N-IgAN patients.

RESULTS

Urinary protein excretion and the degree of hematuria were significantly lower in N-IgAN than IgAN patients (0.50 vs. 0.82 g/day; P = 0.01), (1.33 vs. 2.50; P < 0.001, respectively). Creatinine clearance was higher in N-IgAN than IgAN patients (89.4 vs. 74.4 ml/min; P < 0.001). Histopathologically, N-IgAN patients had significantly less advanced glomerular and tubulointerstitial lesions than IgAN patients. Pathological grades in patients with untreated IgAN were more advanced in a time-dependent manner, whereas there was no relationship between histological grades and time of illness in N-IgAN patients. Frequency of the DD genotype of the ACE gene was significantly lower in N-IgAN (DD/ID+II = 8/76) than IgAN (24/90) patients.

CONCLUSIONS

IgA-negative MesPGN is a distinct type of glomerulopathy with a benign renal prognosis. Insertion/deletion polymorphisms of the ACE gene may play some role in the genesis and progression of MesPGN.

Cost-effectiveness of ACE inhibitor therapy to prevent dialysis in nondiabetic nephropathy: influence of the ACE insertion/deletion polymorphism

INTRODUCTION

End-stage renal disease is associated with high health-care costs and low quality of life compared with chronic kidney disease. The renoprotective effectiveness of angiotensin-converting enzyme inhibitors (ACEi) is largely determined by the ACE insertion/deletion (I/D) polymorphism. We determined the cost-effectiveness of ACEi therapy in nondiabetic nephropathy for the ACE II/ID and for the ACE DD genotype separately. Furthermore, we considered a selective screen-and-treat strategy in which patients are prescribed alternative, more effective, therapy based on their ACE (I/D) polymorphism.

METHODS

Time-dependent Markov models were constructed; cohorts of 1000 patients were followed for 10 years. Data were mainly gathered from the Ramipril Efficacy In Nephropathy trial. Both univariate and probabilistic sensitivity analyses were performed.

RESULTS

ACEi therapy dominated placebo in both the ACE II/ID group (euro15 826, and 0.091 quality-adjusted life years gained per patient) and the ACE DD group (euro105 104 and 0.553 quality-adjusted life years gained). Sensitivity analyses showed 30.2% probability of ACEi being not cost-effective in the ACE II/ID group, against an almost 100% probability of cost-effectiveness in the ACE DD group. A selective screen-and-treat strategy should incorporate an alternative therapy for patients with the ACE II/ID genotype with an at least 9.1% increase in survival time compared with ACEi therapy to be cost-effective. Sensitivity analyses show that higher effectiveness and lower costs of the alternative therapy improve the cost-effectiveness of a screening strategy.

CONCLUSION

ACEi therapy is a cost-saving treatment compared with placebo in nondiabetic nephropathy, irrespective of ACE (I/D) genotype. However, ACEi therapy saved more costs and more health gains were achieved in the ACE DD genotype than in the ACE II/ID genotype. An alternative treatment featuring a modest increase in effectiveness compared with ACEi therapy for patients with the ACE II/ID genotype can be incorporated in a cost-effective or even cost-saving screen-and-treat strategy.

Haplotype structure of five SNPs within the ACE gene in the Tunisian population

BACKGROUND

The Angiotensin-Converting Enzyme (ACE) is a candidate gene in the aetiology of several common diseases. The study of the haplotype structure of this gene is of interest in diagnosis and in pharmacogenomics.

AIM

The study investigated the haplotype profile of single nucleotide polymorphisms (SNPs) within the ACE gene in the Tunisian population and compared it with other populations.

SUBJECTS AND METHODS

Five SNPs (rs1800764, rs4291, rs4309, rs4331, rs4340) covering a region of 15.6 kb of the ACE gene were typed by PCR-digestion in a sample of 100 healthy subjects.

RESULTS

All SNPs were polymorphic and in Hardy-Weinberg equilibrium. A total of 21 haplotypes were identified but only eight had a frequency of more than 1%. The four most common haplotypes had a cumulative frequency of 87.4%. The 'Yin-Yang' phenomenon (the two major haplotypes are complementary at all sites) was found. Linkage disequilibrium between all pairs of loci was highly significant (p<10-5). A simple and efficient statistical procedure was used to identify three important SNPs.

CONCLUSION

The Tunisian population showed a different haplotype structure from the European one for the ACE gene and three important SNPs were identified. These will be very helpful in future association studies in the Tunisian and North African populations.

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

Angiotensin-converting enzyme (ACE) displays potent vasoconstrictive effects, attenuation of fibrinolysis, and platelet activation and aggregation. Recently it was mentioned that the insertion/deletion polymorphism of the ACE gene is associated with ESRD. The lengthy course of IgA Nephropathy (IgAN) and the possibility of good outcomes without therapy suggest nontoxic therapies such as ACE inhibitors and angiotensin receptor blockers (ARBs). However, the correlation between the ACE gene polymorphism and progression of IgAN still requires further approval. Here, the author performs a summative analysis on the recent previous reports on the ACE gene polymorphism and its correlation to progression of IgAN. The meta-analysis was performed to assess the correlation between the pattern of ACE gene polymorphism and progression of IgAN. From five available studies, 346 and 555 patients with (group 1) and without (group 2) the progression of disease are evaluated. According to this study, the frequency of DD genotype in group 1 is significant higher than group 2 (p < 0.05). In addition, the author first reports a non-significant correlation between the ethnicity and the ACE gene polymorphism.

Significance of genetic polymorphisms of the renin–angiotensin–aldosterone system in cardiovascular and renal disease

The angiotensin converting enzyme (ACE) is a component of the renin–angiotensin–aldosterone system (RAAS). The RAAS – involved primarily in blood pressure and sodium homeostasis – is activated in many renal and cardiovascular diseases, and therapy with ACE inhibitors and other blockers of the RAAS has proven to be clinically beneficial. Plasma and tissue levels of ACE are at least partially determined by a genetic polymorphism based on the presence (insertion [I]) or absence (deletion [D]) of a 287 base pair element in intron 16. In particular Asian subjects with the DD genotype (and increased ACE activity) have been reported to be at higher risk for cardiovascular disorders and nephropathy. Numerous studies evaluated the role of the ACE I/D polymorphism as well as other genetic variants of the RAAS in the context of RAAS inhibitor therapy. However, as race and environmental factors, such as salt intake also affect treatment response most studies were underpowered leading to conflicting results.

The kallikrein-kinin system in health and in diseases of the kidney

Since kallikrein was discovered as a vasodilatory substance in human urine, the kallikrein-kinin system (KKS) has been considered to play a physiological role in controlling blood pressure. Gene targeting experiments in mice in which the KKS has been inactivated to varying degrees have, however, questioned this role, because basal blood pressures are not altered. Rather, these experiments have shown that the KKS has a different and important role in preventing changes associated with normal senescence in mice, and in reducing the nephropathy and accelerated senescence-associated phenotypes induced in mice by diabetes. Other experiments have shown that the KKS suppresses mitochondrial respiration, partly by nitric oxide and prostaglandins, and that this suppression may be a key to understanding how the KKS influences senescence-related diseases. Here we review the logical progression and experimental data leading to these conclusions, and discuss their relevance to human conditions.

Angiotensin-converting enzyme gene DD genotype neither increases susceptibility to acute pancreatitis nor influences disease severity

BACKGROUND

The renin-angiotensin system (RAS) has been implied in the pathogenesis of various diseases including acute and chronic pancreatitis. Angiotensin-converting enzyme (ACE) is the key enzyme in activating the RAS. Deletion (D)-type polymorphism in the 16th intron of the ACE gene has been associated with higher serum levels of the enzyme. Inhibition of ACE was found to ameliorate acute pancreatitis in animal models suggesting that ACE plays a role in pathogenesis and progression of acute pancreatitis. Objectives were to investigate the occurrence of the ACE insertion/deletion (I/D) polymorphism in acute pancreatitis patients and its association with the severity of the disease.

MATERIAL AND METHODS

Seventy-nine acute pancreatitis patients and 95 healthy controls were evaluated. Acute pancreatitis cases were grouped as mild or severe according to the Atlanta criteria.

MAIN OUTCOME MEASURE

The presence of the ACE I/D polymorphism.

RESULTS

ACE gene I and D allele frequency of patients (44% and 56%) were similar to controls (45% and 55%, respectively). There were no significant differences in severity of pancreatitis between patients with the ACE-insertion or ACE-insertion/deletion versus ACE-deletion genotypes.

CONCLUSIONS

The ACE gene deletion polymorphism is neither a risk factor for development of acute pancreatitis nor contributes to the severity of disease or development of complications.

Angiotensin converting enzyme insertion/deletion polymorphism and renoprotection in diabetic and nondiabetic nephropathies

Despite the huge amount of studies looking for candidate genes, the ACE gene remains the unique, well-characterized locus clearly associated with pathogenesis and progression of chronic kidney disease, and with response to treatment with drugs that directly interfere with the renin angiotensin system (RAS), such as angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor antagonists (ARA). The II genotype is protective against development and progression of type I and type II nephropathy and is associated with a slower progression of nondiabetic proteinuric kidney disease. ACE inhibitors are particularly effective at the stage of normoalbuminuria or microalbuminuria in both type I and type II diabetics with the II genotype, whereas the DD genotype is associated with a better response to ARA therapy in overt nephropathy of type II diabetes and to ACE inhibitors in male patients with nondiabetic proteinuric nephropathies. The role of other RAS or non-RAS polymorphisms and their possible interactions with different ACE I/D genotypes are less clearly defined. Thus, evaluating the ACE I/D polymorphism is a reliable tool to identify patients at risk and those who may benefit the most of renoprotective therapy with ACE inhibitors or ARA. This may guide pharmacologic therapy in individual patients and help design clinical trials in progressive nephropathies. Moreover, it might help optimize prevention and intervention strategies at population levels, in particular, in countries where resources are extremely limited and 1 million patients continue to die every year of cardiovascular or renal disease.

Angiotensinogen, angiotensine converting enzyme and plasminogen activator inhibitor-1 gene polymorphism in chronic allograft dysfunction

Despite dramatic improvements in first-year patient and graft survival rates, chronic allograft dysfunction (CAD) remains the leading cause of late renal allograft loss, while current immunologic strategies have little effect on this condition. The renin-angiotensin system (RAS) plays an important role in progression of chronic renal disease. It was shown that plasminogen activator inhibitor-1 (PAI-1) functions in the RAS. This study investigates the possible links between angiotensinogen (AGT M235T), angiotensin-converting enzyme (ACE) and PAI-1 genotypes with CAD. Assessments of polymorphism were performed in 127 renal allograft recipients (77 with CAD and 50 with normal renal function). Fifty healthy subjects were also considered for comparison. Genotypes were determined using polymerase chain reaction (PCR) sequence-specific primers and PCR followed by restriction fragment length polymorphism analysis. Kidney recipients with CAD had significantly higher frequencies of the TT than the recipients without CAD (P < 0.05). The transplant recipients with CAD also had significantly higher frequencies of the DD genotype than those without CAD (P < 0.05). No significant differences were observed between the allelic and genotypic distributions of PAI-1 polymorphisms. Therefore, determination of AGT M235T and ACE genotypes prior to transplantation may be useful to identify patients who are at risk for chronic renal transplant dysfunction.

Primer: strategies for identifying genes involved in renal disease

The globally increasing number of patients with end-stage renal disease urges the identification of molecular pathways involved in renal pathophysiology, to serve as targets for intervention. Moreover, the identification of genetic risk factors or protective genes can aid tailored therapy. Tools that can be used to identify genes involved in renal disease include gene expression arrays, linkage analysis and association studies. Arrays are a powerful and widely used approach to the analysis of gene transcription and protein expression, whereas linkage analysis and association studies link disease susceptibility to particular genetic regions. Animal models are available to pinpoint the disease-associated genes. Candidate genes so far identified in renal disease include those encoding the podocyte proteins nephrin and podocin, the transcription factor WT1, the calcium channel TRPC6 and the enzyme phospholipase C-epsilon-1 (in congenital nephrotic syndrome and focal segmental glomerulosclerosis), and carnosinase (in diabetic nephropathy). In addition, linkage studies have identified chromosomal regions implicated in systemic lupus erythematosus, diabetic nephropathy and familial IgA nephropathy. Future studies will elucidate the emerging role of epigenetic regulation of gene expression in renal disease.

The gene polymorphism of the angiotensin I-converting enzyme correlates with tumor size and patient survival in colorectal cancer patients

We studied the putative significance of angiotensin I-converting enzyme (ACE) in colorectal cancer (CRC) biology. Local expression of ACE was investigated by quantitative reverse transcription-polymerase chain reaction and by immunohistochemistry in CRCs and adenomas. ACE insertion (I)/deletion (D) polymorphism was studied in 141 CRC patients and 189 controls. ACE mRNA was upregulated in CRCs compared to corresponding nonlesional tissues (2.5-fold; P = .009). ACE protein was more commonly expressed in adenomas [17 (81%)] and cancer epithelial cells [22 (100%)] than in corresponding non-neoplastic crypt and surface epithelium [2 (10%) and 2 (9%), respectively]. Thirty-seven CRC patients (26%) carried II genotype, 69 (49%) carried ID genotype, and 35 (25%) carried DD genotype. The distribution of the genotypes did not differ from that of controls. Female CRC patients more commonly carried the ID genotype and less frequently the II and DD genotypes compared with male patients (P = .033). Men heterozygous or homozygous for the D-allele had larger tumors compared to carriers of the II genotype (P < .01). Women homozygous for the D-allele lived longer than carriers of the ID and II genotypes. Our study shows that ACE is differentially expressed in CRCs and that gene polymorphism is associated with gender-specific differences in primary tumor size and patient survival.

The angiotensin II/angiotensin II receptor system correlates with nodal spread in intestinal type gastric cancer

We aimed to substantiate the putative significance of angiotensin II receptor type 1 (AT1R) and type 2 (AT2R) for gastric cancer biology by investigating the correlation of their expression with various clinicopathologic variables and patient survival. Local expression of AT1R, AT2R, and angiotensin-converting enzyme (ACE) was investigated by immunohistochemistry in tumor and corresponding nontumor specimens obtained from 100 patients with gastric cancer, and compared with the ACE insertion/deletion gene polymorphism. AT1R and AT2R were found in the tumor epithelial cells of 26 (26%) and 95 (95%) patients, respectively. AT1R was significantly more prevalent (P < 0.001) in intestinal type gastric cancer than in diffuse type gastric cancer. In intestinal type gastric cancer, its expression correlated with the N category (P = 0.009) and the International Union Against Cancer tumor stage (P = 0.024). AT1R+ intestinal type gastric cancers had a larger number of lymph node metastases (P = 0.026), a higher International Union Against Cancer tumor stage (P = 0.032), and a shorter survival time (P = 0.009) than AT1R- tumors. Multivariate analysis with lymph nodes as a dependent variable showed that AT1R status and ACE-I/D gene polymorphism are independent risk factors. Irrespective of the genotype, AT1R+ gastric cancers had a relative risk of lymph node metastases of 4.40 (95% confidence interval, 1.30-14.86). When the ACE genotype was included, the relative risk of having lymph node metastases increased considerably in AT1R+ tumors being heterozygous or homozygous for the ACE D allele (odds ratio, 19.00; 95% confidence interval, 1.45-248.24). Our study shows that AT1R and AT2R are expressed locally in gastric cancer and that the combination of AT1R expression and ACE I/D gene polymorphism correlates with nodal spread in intestinal type gastric cancer.

The genetics of IgA nephropathy

IgA nephropathy is the most common form of primary glomerulonephritis. Variations in clinical manifestations indicate that a diagnosis of IgA nephropathy encompasses multiple disease subsets that cannot be distinguished on the basis of renal pathology or clinical variables alone. Familial forms of the disease have been reported throughout the world, but are probably under-recognized because associated urinary abnormalities are often intermittent in affected family members. IgA nephropathy has complex determination, with different genes probably causing disease in different patient subgroups. Of the many pathogenic mechanisms reported, defects in IgA1 glycosylation that lead to formation of immune complexes have been consistently implicated. Here, we present the evidence for genetic contributions to the disease, review clinical patterns of familial disease, and summarize some of the most promising genetic studies conducted to date. Linkage-based approaches to the study of familial forms of the disease have identified significant or suggestive loci on chromosomes 6q22-23, 2q36, 4q26-31, 17q12-22 and 3p24-23, but no causal gene has yet been identified. Many interesting, but poorly replicated, genetic association studies have also been reported. We discuss recent developments in analytic tools that should enable genetic studies of sporadic forms of disease by the genome-wide association approach.

Relationship between angiotensin-converting enzyme gene insertion or deletion polymorphism and insulin sensitivity in healthy newborns

CONTEXT

It was proposed that the association between low birth weight and adult insulin resistance is principally genetically mediated. The insertion/deletion polymorphism of the angiotensin-converting enzyme gene was associated with insulin sensitivity in adults.

OBJECTIVE

Our goal was to investigate the relationship between angiotensin-converting enzyme gene insertion/deletion polymorphism and the insulin sensitivity in healthy newborns.

PATIENTS AND METHODS

One hundred eighty healthy newborns, all of whom had a 1-minute Apgar score of > 7 and gestational age > 33 weeks, were enrolled in the study. Fasting glucose and insulin levels were measured on day 2 or 3 after birth, and angiotensin-converting enzyme genotype was determined.

RESULTS

The observed frequency distribution of angiotensin-converting enzyme genotypes did not deviate from that predicted by Hardy-Weinberg equilibrium in this group. There were no statistically significant differences in birth size and shape in different angiotensin-converting enzyme genotypes. Those carriers of the genotype homozygous for the deletion allele had the highest logarithmically transformed homeostasis model assessment compared with those who were heterozygous or homozygous for the insertion polymorphism. When compared with those with > or = 1 insertion allele, those of the genotype homozygous for the deletion allele had significantly higher logarithmically transformed fasting insulin and logarithmically transformed homeostasis model assessment results. Regarding birth weight, birth length, ponderal index, and fasting glucose concentration, there were no significant differences between the genotype homozygous for the deletion allele and the genotypes heterozygous or homozygous for the insertion allele.

CONCLUSIONS

In this study, the deletion allele was associated with relatively impaired insulin sensitivity in healthy neonates. It may be a clue to explain the association between the deletion allele and insulin resistance in the long-term.