A population study of ethnic variations in the angiotensin-converting enzyme I/D polymorphism: relationships with gender, hypertension and impaired glucose metabolism

ACE I/D genotype associates with strength in sarcopenic men but not with response to ACE inhibitor therapy in older adults with sarcopenia: Results from the LACE trial

BACKGROUND

Angiotensin II (AII), has been suggested to promote muscle loss. Reducing AII synthesis, by inhibiting angiotensin converting enzyme (ACE) activity has been proposed as a method to inhibit muscle loss. The LACE clinical trial was designed to determine whether ACE inhibition would reduce further muscle loss in individuals with sarcopenia but suffered from low recruitment and returned a negative result. Polymorphic variation in the ACE promoter (I/D alleles) has been associated with differences in ACE activity and muscle physiology in a range of clinical conditions. This aim of this analysis was to determine whether I/D polymorphic variation is associated with muscle mass, strength, in sarcopenia or contributed to the lack of response to treatment in the LACE study.

METHODS

Sarcopenic individuals were recruited into a 2x2 factorial multicentre double-blind study of the effects of perindopril and/or leucine versus placebo on physical performance and muscle mass. DNA extracted from blood samples (n = 130 72 women and 58 men) was genotyped by PCR for the ACE I/D polymorphism. Genotypes were then compared with body composition measured by DXA, hand grip and quadriceps strength before and after 12 months' treatment with leucine and/or perindopril in a cross-sectional analysis of the influence of genotype on these variables.

RESULTS

Allele frequencies for the normal UK population were extracted from 13 previous studies (I = 0.473, D = 0.527). In the LACE cohort the D allele was over-represented (I = 0.412, D = 0.588, p = 0.046). This over-representation was present in men (I = 0.353, D = 0.647, p = 0.010) but not women (I = 0.458, D = 0.532, p = 0.708). In men but not women, individuals with the I allele had greater leg strength (II/ID = 18.00 kg (14.50, 21.60) vs DD = 13.20 kg (10.50, 15.90), p = 0.028). Over the 12 months individuals with the DD genotype increased in quadriceps strength but those with the II or ID genotype did not. Perindopril did not increase muscle strength or mass in any polymorphism group relative to placebo.

CONCLUSION

Our results suggest that although ACE genotype was not associated with response to ACE inhibitor therapy in the LACE trial population, sarcopenic men with the ACE DD genotype may be weaker than those with the ACE I/D or II genotype.

Interactions of the eNOS and ACE genes and cigarette smoking in chronic obstructive pulmonary disease

Background

Chronic obstructive pulmonary disease (COPD) is a complex disorder with unexplained heritability. Interactions of genetic and environmental factors are thought to be crucial in COPD. So, we aim to examine interactions of the endothelial nitric oxide synthase (eNOS) and angiotensin converting enzyme (ACE) genes and cigarette smoking in COPD.

Methods

The eNOS G 894T and ACE ID variants were analyzed in 122 COPD patients and 200 controls from Serbia. The effect of the variants on COPD was assessed by logistic regression. Interactions between eNOS, ACE and cigarette smoking in COPD were evaluated using a case-control model. Interaction between the genes was analyzed in silico.

Results

No effect of the eNOS G 894T and ACE ID variants on COPD was found in our study. Gene-gene interaction between the eN OS T T and A CE D was identified (p=0.033) in COPD. The interaction is realized within the complex network of biochemical pathways. Gene-environment interactions between the eNOS T and cigarette smoking (p=0.013), and the ACE II and cigarette smoking (p=0.009) were detected in COPD in our study.

Conclusions

This is the first research to reveal interactions of the eNOS and ACE genes and cigarette smoking in COPD progressing our understanding of COPD heritability and contributing to the development of appropriate treatments.

The COVID-19 Pandemic and Explaining Outcomes in Africa: Could Genomic Variation Add to the Debate?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of COVID-19, emanated from the Wuhan Province in China and rapidly spread across the globe causing extensive morbidity and mortality rate, and affecting the global economy and livelihoods. Contrary to early predictions of "body bags" across Africa, the African COVID-19 pandemic was marked by apparent low case numbers and an overall mortality rate when compared with the other geographical regions. Factors used to describe this unexpected pattern included a younger population, a swifter and more effective national health policy, limited testing capacities, and the possibility of inadequate reporting of the cases, among others. However, despite genomics contributing to interindividual variations in many diseases across the world, there are inadequate genomic and multiomics data on COVID-19 in Africa that prevent richer transdisciplinary discussions on the contribution of genomics to the spread of COVID-19 pandemic. To invite future debates on comparative studies of COVID-19 genomics and the pandemic spread around the world regions, this expert review evaluates the reported frequency distribution of genetic variants in candidate genes that are likely to affect COVID-19 infection dynamics/disease outcomes. We propose here that genomic variation should be considered among the many factors determining the COVID-19 infection and its outcomes in African populations and across the world.

Cardiovascular Complications in Major 21st Century Viral Epidemics and Pandemics: an Insight into COVID-19

There have many major history-defining epidemics and pandemics in the 21st century. It is well known that acute infections can cause cardiovascular (CV) complications, especially in those with underlying cardiac disease. The variation in rates and types of CVD complications in major 21st century epidemics and pandemics varies greatly. The coronavirus disease 2019 (COVID-19) pandemic has caused the turmoil of the century and has COVID-19 has resulted in substantial human and economic loss. The novelty of COVID-19 and emerging CV effects is a new entity. In this review, we discuss the major epidemics and pandemics of the 21st century and associated CVD complications.

Autoimmune inflammatory rheumatic diseases and COVID-19 outcomes in South Korea: a nationwide cohort study

Background

Real-world evidence on the association between autoimmune inflammatory rheumatic diseases, therapies related to these diseases, and COVID-19 outcomes are inconsistent. We aimed to investigate the potential association between autoimmune inflammatory rheumatic diseases and COVID-19 early in the COVID-19 pandemic.

Methods

We did an exposure-driven, propensity score-matched study using a South Korean nationwide cohort linked to general health examination records. We analysed all South Korean patients aged older than 20 years who underwent SARS-CoV-2 RT-PCR testing between Jan 1 and May 30, 2020, and received general health examination results from the Korean National Health Insurance Service. We defined autoimmune inflammatory rheumatic diseases (inflammatory arthritis and connective tissue diseases) based on the relevant ICD-10 codes, with at least two claims (outpatient or inpatient) within 1 year. The outcomes were positive SARS-CoV-2 RT-PCR test, severe COVID-19 (requirement of oxygen therapy, intensive care unit admission, application of invasive ventilation, or death), and COVID-19-related death. Adjusted odds ratios (ORs) with 95% CIs were estimated after adjusting for the potential confounders.

Findings

Between Jan 1 and May 30, 2020, 133 609 patients (70 050 [52·4%] female and 63 559 [47·6%] male) completed the general health examination and were tested for SARS-CoV-2; 4365 (3·3%) were positive for SARS-CoV-2, and 8297 (6·2%) were diagnosed with autoimmune inflammatory rheumatic diseases. After matching, patients with an autoimmune inflammatory rheumatic disease showed an increased likelihood of testing positive for SARS-CoV-2 (adjusted OR 1·19, 95% CI 1·03–1·40; p=0·026), severe COVID-19 outcomes (1·26, 1·02–1·59; p=0·041), and COVID-19-related death (1·69, 1·01–2·84; p=0·046). Similar results were observed in patients with connective tissue disease and inflammatory arthritis. Treatment with any dose of systemic corticosteroids or disease-modifying antirheumatic drugs (DMARDs) were not associated with COVID-19-related outcomes, but those receiving high dose (≥10 mg per day) of systemic corticosteroids had an increased likelihood of a positive SARS-CoV-2 test (adjusted OR 1·47, 95% CI 1·05–2·03; p=0·022), severe COVID-19 outcomes (1·76, 1·06–2·96; p=0·031), and COVID-19-related death (3·34, 1·23–8·90; p=0·017).

Interpretation

Early in the COVID-19 pandemic, autoimmune inflammatory rheumatic diseases were associated with an increased likelihood of a positive SARS-CoV-2 PCR test, worse clinical outcomes of COVID-19, and COVID-19-related deaths in South Korea. A high dose of systemic corticosteroid, but not DMARDs, showed an adverse effect on SARS-CoV-2 infection and COVID-19-related clinical outcomes.

Funding

National Research Foundation of Korea.

Renin-angiotensin-aldosterone system blockers and region-specific variations in COVID-19 outcomes: findings from a systematic review and meta-analysis

BACKGROUND AND AIMS

Coronavirus disease 2019 (COVID-19) has been observed to cause a high mortality in people with cardiometabolic diseases. Renin-angiotensin-aldosterone system (RAAS) blockers enhance the expression of ACE2, the binding receptor of SARS-CoV-2, and can enhance viral infectivity. We aim to provide a pooled estimate of the effect of RAAS blockers on COVID-19 outcomes.

METHODS

A literature search was performed using MEDLINE/PubMed, Google Scholar and preprint servers. All clinical studies analyzing the effect of RAAS blockers on clinical outcomes in COVID-19 patients were included in this study. Newcastle-Ottawa scale was used for quality assessment of studies. MOOSE checklist was followed. Mortality and severity outcomes were recorded as pooled odds ratio (OR) with 95% Confidence Intervals (CIs) and level of heterogeneity (I 2). Odds of mortality was the primary outcome. Odds of severity, hospitalization, intensive care unit (ICU) admission, mechanical ventilation (MV), steroid use and acute kidney injury were the secondary outcomes. Severity outcomes were chosen depending upon the definition used by respective authors. Country-specific variations and effects of individual class of RAAS blockers were also explored.

RESULTS

In total 47 published studies were included in the final analysis, with a total of 26,432 patients from 31 studies in mortality analysis and 20,127 patients from 23 studies in severity analysis. No increased risk of mortality [Pooled OR 0.91 (0.65-1.26), I 2 = 89%] or severity [Pooled OR 1.08 (0.79-1.46), I 2 = 88%] was seen with RAAS blockers. The drug class was protective in hypertension [pooled OR 0.63 (0.46-0.86), I 2 = 58%]. Severity of COVID-19 outcomes was high for Europeans [Pooled OR 2.08 (1.52-2.85), I 2 = 77%] and US patients [Pooled OR 1.87 (1.62-2.17)]. Nearly 4 times higher risk of hospitalization and 2 times higher risk of ICU admission and MV were observed in US patients. Class-wise, angiotensin receptor blocker use was associated with 1.6 times higher odds of severity, mainly in Europeans.

CONCLUSION

RAAS blockers are not associated with increased mortality in COVID-19 patients and should be continued in hypertensives. US and European patients are at higher risk of severe outcomes. Pharmacogenetic differences may explain the ethnicity-related variations.

PLAIN LANGUAGE SUMMARY

Effect of RAAS-blocking medicines on COVID-19 Background and aims: Higher deaths have been observed in COVID-19 patients who have other long-term diseases such as heart disease, diabetes, and high blood pressure. Many of these patients are prescribed a class of medicines called RAAS blockers (ramipril, telmisartan, etc). We studied whether the use of these medicines worsens the course of COVID-19 disease in these patients or causes excess deaths.Methods: We conducted a pooled analysis of 47 observational studies on the use of RAAS blocker drugs in COVID-19 patients.Results: We found that RAAS blockers do not cause excess deaths in patients with COVID-19. On the contrary, they have benefits if prescribed to those with high blood pressure. We also found that whereas European and US patients of COVID-19 taking these medicines had higher disease severity, this was not the case for Chinese patients.Conclusion: Theremay be some genetic and other factors responsible for differences by ethnicity.

Ethnic and age-specific acute lung injury/acute respiratory distress syndrome risk associated with angiotensin-converting enzyme insertion/deletion polymorphisms, implications for COVID-19: A meta-analysis

Background

The reported association between an insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene and the risk for acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) remains controversial despite the publication of four meta-analyses on this topic. Here, we updated the meta-analysis with more studies and additional assessments that include adults and children within the context of the coronavirus disease 2019 (COVID-19) pandemic.

Methods

Sixteen articles (22 studies) were included. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using three genetic models (allele, recessive and dominant), in which ARDS patients were compared with non-ARDS patients (A1) and healthy controls (A2). Mortality outcomes were also assessed (A3). The influence of covariates was examined by meta-regression. Bonferroni correction was performed for multiple pooled associations. Subgroup analyses based on ethnicity (Asians, Caucasians) and life stage (adults, children) were conducted. Heterogeneity was addressed with outlier treatment.

Results

This meta-analysis generated 68 comparisons, 21 of which were significant. Of the 21, four A1 and three A3 highly significant (P^a = 0.00001–0.0008) outcomes withstood Bonferroni correction. For A1, allele and recessive associations were found in overall (OR 0.49, 95% CI 0.39–0.61), Caucasians (OR 0.46, 95% CI 0.35–0.61) and children (ORs 0.49–0.66, 95% CI 0.33–0.84) analyses. For A3, associations were found in overall (dominant: OR 0.45, 95% CI 0.29–0.68) and Asian subgroup (allele/ dominant: ORs 0.31–0.39, 95% CIs 0.18–0.63) analyses. These outcomes were either robust, or statistically powered or both and uninfluenced by covariates.

Conclusions

Significant associations of the ACE I/D polymorphism with the risk of ALI/ARDS were indicated in Caucasians and children as well as in Asians in mortality analysis. These findings were underpinned by high significance, high statistical power and robustness. ACE genotypes may be useful for ALI/ARDS therapy for patients with COVID-19.

COVID19 in South Asians/Asian Indians: Heterogeneity of data and implications for pathophysiology and research

Despite a large population and limited health infrastructure, the incidence and mortality of Coronavirus Disease 2019 (COVID-19) has been lower in South Asia than many regions. The underlying reasons and mechanisms for this relative protection are not established. However both genetic and environmental factors might play a role. Polymorphisms in ACE2 gene, ACE gene and in genes for some of the host cell proteases could affect the viral entry and replication. There is some evidence that HLA polymorphisms and several pathways involved in immune and inflammatory response could contribute to ethnic variation. Cross immunity because of past exposure to viral infections as well as malaria is likely to protect from the severe manifestations of disease. Role of BCG vaccination in trained innate immunity is recognised and could be a protective factor against COVID-19. There is limited evidence of the possibility of a less virulent viral strain circulating in South Asia. There is evidence from different parts of the world that temperature and humidity can influence viral survival as well as the host immune response. Finally implementation of early containment measures by some South Asian countries has also contributed to a less disease burden.

Estrogen-related mechanisms in sex differences of hypertension and target organ damage

Hypertension (HTN) is a primary risk factor for cardiovascular (CV) events, target organ damage (TOD), premature death and disability worldwide. The pathophysiology of HTN is complex and influenced by many factors including biological sex. Studies show that the prevalence of HTN is higher among adults aged 60 and over, highlighting the increase of HTN after menopause in women. Estrogen (E2) plays an important role in the development of systemic HTN and TOD, exerting several modulatory effects. The influence of E2 leads to alterations in mechanisms regulating the sympathetic nervous system, renin-angiotensin-aldosterone system, body mass, oxidative stress, endothelial function and salt sensitivity; all associated with a crucial inflammatory state and influenced by genetic factors, ultimately resulting in cardiac, vascular and renal damage in HTN. In the present article, we discuss the role of E2 in mechanisms accounting for the development of HTN and TOD in a sex-specific manner. The identification of targets with therapeutic potential would contribute to the development of more efficient treatments according to individual needs.

Association Between Polymorphism of the Angiotensin I Converting Enzyme Gene and Hypertension in Turkish Type II Diabetic Patients

It has been suggested that an insertion/deletion (I/D) polymorphism in intron 16 of the angiotensin converting enzyme (ACE) gene may be associated with essential hypertension. The aim of this study was to examine the association between ACE I/D polymorphism with blood pressure level and hypertension status in Turkish type 2 diabetic subjects. Hundred and seven hypertensive (78 female, 29 male) and 132 normotensive type 2 diabetic subjects (73 female, 59 male) and 138 sex and age matched control subjects (87 female, 51 male) without diabetes and hypertension were included into the study. The I/D polymorphism was determined by polymerase chain reaction (PCR). There were no statistically difference in genotypic and allelic frequencies of the ACE I/D polymorphism between the hypertensive and normotensive diabetic patients and control subjects. Also no significant differences was detected in systolic and diastolic blood pressure among three different genotypes. ACE I/D polymorphism does not seem to play an important role in the development of hypertension in Turkish type 2 diabetic subjects, but prospective studies may show an association between ACE gene polymorphism and the development of hypertension in diabetic subjects.

A meta-analysis on the association of genetic polymorphism of the angiotensin-converting enzyme and coronary artery disease in the chinese population

OBJECTIVE

To investigate the association between genotype insertion or deletion polymorphism of the angiotensin-converting enzyme gene (ACE) and susceptibility to coronary artery disease (CAD) in Chinese Han population.

METHODS

We conducted a comprehensive search for the OR value of contrast between the group of genotype insertion or deletion polymorphism of the ACE and the group of CAD as an effective index. A meta-analysis (Stata 12.0) was used to test the heterogeneity of the results, combine the values for effect, conduct sensitivity analysis, and basic evaluation.

RESULTS

A total of 638 studies were found on the association between polymorphisms of the angiotensin-converting enzyme gene and CAD, of which 44 studies met the inclusion criteria. In total, our study included 5619 cases and 4865 controls. The heterogeneity test of each study (P < 0.001) was carried out using a random effect model. The OR value of DD/ID+II was 1.95, 95% confidence interval (95%CI) (1.66-2.29). The OR value of II/DI+DD was 0.63, 95%CI (0.55-0.72). The funnel figure is basically symmetrical and the results of the sensitivity analysis were stable.

CONCLUSION

The DD genotype of the angiotensin converting enzyme gene may be a weaker risk factor for CAD in the Chinese Han population.

Effects of Interactions among Gene Polymorphisms of the Renin–Angiotensin-Aldosterone System on Hypertension in Turkish People from Southeast Anatolia

Introduction: Hypertension (HT) is characterized by high blood pressure. The reninangiotensin-aldosterone system (RAAS) plays a crucial role in blood pressure (BP) regulation by maintaining vascular tone and the water-sodium balance. We aimed to investigate whether there is any relation between AGT (M235T), ACE (I/D), and AGTR1 (A1166C) genetic polymorphisms and hypertension among Turkish people from Southeast Anatolia.

Method and Results: A total of 210 individuals, consisting of 102 healthy controls and 108 patients with essential hypertension admitted to the Cardiology Department of the Adıyaman University Research and Application Hospital were included the study. DNA isolation was performed from the blood samples via commercial kit. Genotype determination was determined using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Statistically significant differences were found between the control and patient groups in terms of genotype distribution and allelic frequencies of ACE I/D polymorphisms. Significant differences were found in the frequencies of ICM, DCM, DCT, DAT between the patient and control groups.

Conclusions: In this study, we found a significant association of ACE I/D polymorphism with HT, and we showed that the I allele can increase the risk of HT in Turkish people from Southeast Anatolia. Although we did not find any association between independent AGT M235T and AGT1R A1166C polymorphisms and HT, we observed that the DCM, DCT, and DAT haplotypes of ACE/AGT1R/AGT polymorphisms reduced the risk of hypertension, while the ICM haplotype increased it.

Serum concentration of renin-angiotensin system components in association with ACE I/D polymorphism among hypertensive subjects in response to ACE inhibitor therapy

Background: Renin-angiotensin system (RAS) is a complex network of enzymes and peptides with the essential role in blood pressure control. The relationships between RAS components, RAS-related genetic polymorphisms and therapy response in essential hypertension (EH) were widely explored but the results were inconclusive. Aim: The aim of this study was to explore the functional role of ACE insertion/deletion (I/D) polymorphism on the systemic quantity of angiotensin-converting enzyme (ACE), its homolog - ACE2, chymase and angiotensin II in EH patients with respect to achieved therapeutic blood pressure control. Results: Genotyping of ACE I/D polymorphism was performed among 140 patients with EH from Bulgaria. The serological analyses reveal the significant elevation of the serum quantity of all investigated enzymes in EH than normotensive controls. In addition, serum ACE2 (183.57 pg/ml; vs. 151.78 pg/ml; p = 0.02) and chymase (68.5 pg/ml; vs. 23.66 pg/ml; p = 0.034) were significantly higher in patients with uncontrolled EH than controlled EH in response to ACE-inhibitory therapy. Also, ACE I/D polymorphism showed a significant impact on the serum ACE and chymase levels. ACE quantity was the highest among carriers of DD-genotype, followed by ID and II-genotype. Contrary, chymase was in the highest quantity in II-genotype compared to ID-genotype (p = 0.025) and DD-genotype (p = 0.044). Conclusions: Our results suggest that insufficient blood pressure control by ACE-inhibitory therapy could be associated with elevation of serum ACE2 and chymase levels. Also, it appears that ACE I/D polymorphism may influence the circulating quantity of chymase in addition to ACE.

Hypertension, diabetes and cardiovascular risk in ethnic minorities in the UK

Mortality from coronary heart disease (CHD), stroke and end-stage renal failure (ESRF) is high in South Asian (Indo-Asian) migrants in the UK. This is associated with a high prevalence of diabetes and hypertension.

Mortality from stroke and ESRF is also high in migrants to the UK of black African origin. However, CHD mortality is low in this group. This pattern of mortality is also associated with a high prevalence of hypertension and diabetes.

Conventional risk factors, such as cigarette smoking and hypercholesterolaemia, are less prevalent in ethnic minority populations in the UK and unlikely to explain the differences seen between groups, although each risk factor is likely to contribute to the variation in vascular disease within each group.

Insertion/Insertion Genotype of Angiotensin I-Converting-Enzyme Gene Predicts Risk of Myocardial Infarction in North East India

Myocardial infarction (MI) is common in India and the disease occurs at a relatively younger age. We wanted to look for association of Angiotensin I-converting enzyme (ACE) gene with MI in North East India. We also wanted to examine possible environmental interaction of ACE gene with established cardiovascular risk factors in causation of MI. In the study carried out in Assam Medical College, 200 consecutive confirmed cases of MI were recruited. Equal numbers of age- and sex-matched control subjects from hospital workers and patients attending the hospital for diseases unrelated to cardiovascular disease were enrolled. Structured questionnaires were used to note demographic and clinical factors. Cardiovascular risk factors were determined from history, physical examination and biochemical investigations. ACE insertion/deletion (I/D) polymorphism was determined by PCR method. Interaction of ACE gene with other risk factors was noted. The study identified ACE II genotype (odds ratio = 3.02; 95% CI 1.40-6.51), smoking, hypertension, diabetes and serum triglyceride > 150 mg/dl as independent risk factors for MI. ACE II genotype showed greater risk in non-smokers, non-hypertensives, non-diabetics and in subjects with LDL-C < 130 mg/dl. Low HDL cholesterol enhanced the genetic risk. Subjects with ACE II genotype have an independent risk of developing MI, specially in low cardiovascular risk subjects.

The insertion-deletion polymorphism of the ACE gene is associated with increased blood pressure in women at the end of pregnancy

INTRODUCTION

Malfunctioning of the cardiovascular system during pregnancy may be responsible for adverse effects on the 'mother-fetus' system. The cardiovascular system of a pregnant woman develops adaptation to the increased load. Angiotensin-converting enzyme (ACE) is known to play an important role in the adaptation. The present study was designed to investigate whether the insertion-deletion (I/D) polymorphism of the ACE gene is associated with the level of arterial blood pressure in women before and during pregnancy.

MATERIALS AND METHODS

The level of blood pressure was measured in 591 Russian women (Central Russia) before and during (37-40 weeks term) pregnancy. The women were divided into three groups which were hypertensive, hypotensive, and normotensive according to blood pressure level. Genotyping of the ACE I/D polymorphism was performed using polymerase chain reaction (PCR) and amplified fragment length polymorphism assay.

RESULTS

Women with genotype DD showed the highest blood pressure level both during and at the end of pregnancy (p<0.05). The highest frequencies of allele D and genotype DD were found in pregnant women in the hypertensive group.

CONCLUSIONS

The deletion variant of the ACE gene is associated with high blood pressure level at the end of pregnancy.

Insertion/deletion polymorphism of the angiotensin-converting enzyme gene and the risk of hypertension among residents of two cities, South-South Nigeria

BACKGROUND

Hypertension is a public health challenge due to its high prevalence, and is a major risk factor for cardiovascular diseases. This study was designed to determine the frequency of the I/D polymorphism of the angiotensin-converting enzyme gene and its association with hypertension in a sample population of Calabar and Uyo, South-South Nigeria.

MATERIALS AND METHODS

A population-based case control design consisting of total of 1224 participants, 612 each of patients and controls, were randomly recruited from hypertension clinics and the general population. The I/D polymorphism was investigated using polymerase chain reaction. Multiple regression and odds ratio (OR) was applied to test whether the ID genotypes were predictors of hypertension.

RESULTS

The I/D genotype frequencies were 73(12%), 262(43%) and 277(45%); 74(12%), 303(50%) and 235(38%) for the II, ID, DD genotype in patient and control groups, respectively. A higher frequency of the ID genotype was observed in controls of which 208(61%) were females. By multiple regression analysis, age was a predictor for SBP in patients, r = 0.596, and DBP in controls, r = 0.555. Gender, Body mass index, I/D genotypes were not significant predictors for hypertension but the I/D polymorpism was associated with an increased risk for hypertension with an OR of 1.15 95%CI (0.924-1.456).

CONCLUSION

The I/D polymorphism of the angiotensin-converting enzyme gene was a risk factor for hypertension in the sample population of Calabar and Uyo. This research will form baseline information for subsequent molecular studies in this population.

Frequency of APOE, MTHFR and ACE polymorphisms in the Zambian population

Background

Polymorphisms within the apolipoprotein-E (APOE), Methylenetetrahydrofolate reductase (MTHFR) and Angiotensin I-converting enzyme (ACE) genes has been associated with cardiovascular and cerebrovascular disorders, Alzheimer’s disease and other complex diseases in various populations. The aim of the study was to analyze the allelic and genotypic frequencies of APOE, MTHFR C677T and ACE I/D gene polymorphisms in the Zambian population.

Results

The allele frequencies of APOE polymorphism in the Zambian populations were 13.8%, 59.5% and 26.7% for the ε2, ε3 and ε4 alleles respectively. MTHFR C677T and ACE I/D allele frequencies were 8.6% and 13.8% for the T and D minor alleles respectively. The ε2ε2 genotype and TT genotype were absent in the Zambian population. The genetic distances between Zambian and other African and non-African major populations revealed an independent variability of these polymorphisms.

Conclusion

We found that the APOE ε3 allele and the I allele of the ACE were significantly high in our study population while there were low frequencies observed for the MTHFR 677 T and ACE D alleles. Our analysis of the APOE, MTHFR and ACE polymorphisms may provide valuable insight into the understanding of the disease risk in the Zambian population.

Association analysis of ACE and ACTN3 in elite Caucasian and East Asian swimmers

PURPOSE

Polymorphic variation in the angiotensin-converting enzyme (ACE) and α-actinin-3 (ACTN3) genes has been reported to be associated with endurance and/or power-related human performance. Our aim was to investigate whether polymorphisms in ACE and ACTN3 are associated with elite swimmer status in Caucasian and East Asian populations.

METHODS

ACE I/D and ACTN3 R577X genotyping was carried out for 200 elite Caucasian swimmers from European, Commonwealth, Russian, and American cohorts (short and middle distance, ≤400 m, n = 130; long distance, >400 m, n = 70) and 326 elite Japanese and Taiwanese swimmers (short distance, ≤100 m, n = 166; middle distance, 200-400 m, n = 160). Genetic associations were evaluated by logistic regression and other tests accommodating multiple testing adjustment.

RESULTS

ACE I/D was associated with swimmer status in Caucasians, with the D allele being overrepresented in short-and-middle-distance swimmers under both additive and I-allele-dominant models (permutation test P = 0.003 and P = 0.0005, respectively). ACE I/D was also associated with swimmer status in East Asians. In this group, however, the I allele was overrepresented in the short-distance swimmer group (permutation test P = 0.041 and P = 0.0098 under the additive and the D-allele-dominant models, respectively). ACTN3 R577X was not significantly associated with swimmer status in either Caucasians or East Asians.

CONCLUSIONS

ACE I/D associations were observed in these elite swimmer cohorts, with different risk alleles responsible for the associations in swimmers of different ethnicities. The functional ACTN3 R577X polymorphism did not show any significant association with elite swimmer status, despite numerous previous reports of associations with "power/sprint" performance in other sports.

Association of angiotensin-converting enzyme and angiotensin-converting enzyme-2 gene polymorphisms with essential hypertension in the population of Odisha, India

BACKGROUND

Hypertension is a serious health issue worldwide and essential hypertension, which includes 90-95% of the cases, is influenced by both genetic and environmental factors. Identification of these factors may help in control of this disease. The Insertion/Deletion (I/D) polymorphism in Angiotensin-Converting Enzyme (ACE) gene and rs2106809 (C > T) polymorphism in Angiotensin-Converting Enzyme 2 (ACE2) gene have been reported to be associated with essential hypertension in different populations.

AIM

To investigate the association of ACE I/D and ACE2 rs2106809 polymorphisms with essential hypertension in the population of Odisha, an eastern Indian state.

SUBJECTS AND METHODS

A total of 246 hypertensives (159 males and 87 females) and 274 normotensives (158 males and 116 females) were enrolled in the study. Detailed anthropometric data, tobacco, alcohol and food habits were recorded and 2 ml of venous blood was collected for biochemical and genetic analysis.

RESULTS

The DD genotype of ACE and TT genotype of ACE2 were significantly high among female hypertensives, while T allele of ACE2 was linked to male hypertensives. In the male population, alcohol was also identified as a potential risk factor.

CONCLUSION

Among females, ACE I/D and ACE2 rs2106809 polymorphisms, while among males, ACE2 rs2106809 polymorphism and alcohol consumption are associated with essential hypertension in the study population.

A study on the polymorphisms of the renin-angiotensin system pathway genes for their effect on blood pressure levels in males from Algeria

INTRODUCTION

Several studies have assessed the relationship between blood pressure (BP) and polymorphisms within the genes encoding angiotensinogen (AGT), angiotensin II type 1 receptor (AT1R) and angiotensin-converting enzyme (ACE). However, considering the relatively large discrepancy in frequency and impact of these variants between ethnic groups and populations, still unavailable data from Algerian population are needed.

OBJECTIVE

Our purpose is to evaluate the association between the AGT M235T, AT1R +1166A/C and ACE I/D polymorphisms and variations in systolic (SBP), diastolic (DBP) and pulse pressure (PP) values.

METHODS

The associations with BP were assessed in a representative sample of 115 male subjects free of coronary heart disease (CHD). The AGT M235T, AT1R +1166A/C and ACE I/D polymorphisms were determined by PCR-ASO and PCR-RFLP analysis, respectively.

RESULTS

We showed no associations between the AGT M235T, AT1R +1166A/C nor the ACE I/D polymorphisms with variations in BP values. However, concerning the ACE I/D polymorphism, subjects carrying the ACE I allele tended to have higher SBP (+4.1 mmHg) and PP values (+3.2 mmHg) than DD subjects (adjusted p = 0.087 and p = 0.102, respectively).

CONCLUSION

The ACE I/D polymorphism needs further investigation in a larger Algerian study, especially concerning its putative impact on SBP and PP.

Risk of pneumonia associated with use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers: systematic review and meta-analysis

OBJECTIVE

To systematically review longitudinal studies evaluating use of angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) and risk of pneumonia.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline through PubMed, Web of Science with conference proceedings (inception to June 2011), and US Food and Drug Administration website (June 2011). Systematic reviews and references of retrieved articles were also searched.

STUDY SELECTION

Two reviewers independently selected randomised controlled trials and cohort and case-control studies evaluating the use of ACE inhibitors or ARBs and risk of pneumonia and retrieved characteristics of the studies and data estimates.

DATA SYNTHESIS

The primary outcome was incidence of pneumonia and the secondary outcome was pneumonia related mortality. Subgroup analyses were carried according to baseline morbidities (stroke, heart failure, and chronic kidney disease) and patients' characteristics (Asian and non-Asian). Pooled estimates of odds ratios and 95% confidence intervals were derived by random effects meta-analysis. Adjusted frequentist indirect comparisons between ACE inhibitors and ARBs were estimated and combined with direct evidence whenever available. Heterogeneity was assessed using the I(2) test.

RESULTS

37 eligible studies were included. ACE inhibitors were associated with a significantly reduced risk of pneumonia compared with control treatment (19 studies: odds ratio 0.66, 95% confidence interval 0.55 to 0.80; I(2) = 79%) and ARBs (combined direct and indirect odds ratio estimate 0.69, 0.56 to 0.85). In patients with stroke, the risk of pneumonia was also lower in those treated with ACE inhibitors compared with control treatment (odds ratio 0.46, 0.34 to 0.62) and ARBs (0.42, 0.22 to 0.80). ACE inhibitors were associated with a significantly reduced risk of pneumonia among Asian patients (0.43, 0.34 to 0.54) compared with non-Asian patients (0.82, 0.67 to 1.00; P<0.001). Compared with control treatments, both ACE inhibitors (seven studies: odds ratio 0.73, 0.58 to 0.92; I(2)=51%) and ARBs (one randomised controlled trial: 0.63, 0.40 to 1.00) were associated with a decrease in pneumonia related mortality, without differences between interventions.

CONCLUSIONS

The best evidence available points towards a putative protective role of ACE inhibitors but not ARBs in risk of pneumonia. Patient populations that may benefit most are those with previous stroke and Asian patients. ACE inhibitors were also associated with a decrease in pneumonia related mortality, but the data lacked strength.

Angiotensin-converting enzyme (ACE) genotypes and disability in hospitalized older patients

The association between angiotensin-converting enzyme (ACE) genotypes and functional decline in older adults remains controversial. To assess if ACE gene variations influences functional abilities at older age, the present study explored the association between the common ACE insertion/deletion (I/D) polymorphism and disability measured with activities of daily living (ADL) in hospitalized older patients. We analyzed the frequency of the ACE genotypes (I/I, I/D, and D/D) in a population of 2,128 hospitalized older patients divided according to presence or absence of ADL disability. Logistic regression analysis adjusted for possible confounding factors, identified an association between the I/I genotype with ADL disability (OR=1.54, 95% CI 1.04-2.29). This association was significant in men (OR=2.01, 95% CI 1.07-3.78), but not in women (OR=1.36, 95% CI 0.82-2.25). These results suggested a possible role of the ACE polymorphism as a genetic marker for ADL disability in hospitalized older patients.

The association between circulating angiotensin-converting enzyme and cardiovascular risk in the elderly: a cross-sectional study

INTRODUCTION

A polymorphism in the angiotensin-converting enzyme gene (ACE I/D polymorphism) has been associated with increased risk for cardiovascular disease (CVD). This polymorphism affects the level of circulating ACE, but there is great individual variation, even between those with the same genotype. Few previous studies have investigated the link between circulating ACE and cardiovascular risk. The aim of this study was to investigate this association, and to examine the relationship between ACE level, ACE genotype and CVD.

MATERIALS AND METHODS

The study population consisted of 322 men and 350 women aged 69-87. Plasma ACE level was determined using enzyme-linked immunosorbent assay (ELISA), and ACE genotype was analysed using PCR followed by gel electrophoresis.

RESULTS

In men, ACE levels increased with increasing number of cardiovascular risk factors (p = 0.003). There was a significant association in men between increased ACE level and both diabetes (p = 0.007) and smoking (p = 0.037).

CONCLUSIONS

This study shows that cardiovascular risk factors (such as smoking and diabetes) are associated with higher levels of circulating ACE in men. High ACE levels may represent one of the cellular mechanisms involved in producing the vascular damage associated with cardiovascular risk factors.

Angiotensin-converting enzyme gene insertion/deletion polymorphism in Egyptian patients with myocardial infarction

Introduction. This work aimed to test the association of the angiotensin-converting enzyme gene insertion/deletion (I/D) polymorphism with myocardial infarction.

Subjects and methods. This study comprised 79 Egyptian myocardial infarction cases with a mean age of 54.4±9.9 years including 60 males and 19 females, plus 238 healthy unrelated individuals of nearly matched age and sex as a control group. For all subjects, DNA testing for the angiotensin-converting enzyme gene I/D polymorphism was done using PCR amplification for detection of both the D and I alleles followed by a second run PCR specific for the I allele for samples typed as DD in the first run.

Results. Cases had a higher frequency of DD (29.1%) and ID (62.0%) genotypes than II (8.9%) genotype, with a higher frequency of D allele than I allele (64.4% vs. 33.6%). Compared to controls, cases had a significantly higher frequency of ID genotype (62.0% vs. 47.5%, p<0.05).This was more apparent among cases in the low risk group (p=0.002) than in the high risk group (p=0.041).

Conclusion. The angiotensin-converting enzyme gene I/D polymorphism is probably a risk factor for ischaemic heart disease among Egyptian cases, particularly if integrated with other environmental and genetic risk factors.

Prevalence of the angiotensin I converting enzyme gene insertion/deletion polymorphism in a healthy Turkish population

Angiotensin converting enzyme (ACE) plays an essential role in the renin-angiotensin system. It converts angiotensin I to angiotensin II and inactivates bradykinin and tachykinins. Numerous studies have been published investigating associations of the ACE gene I/D polymorphism with various pathophysiological conditions. We examined the prevalence of the ACE I/D polymorphism in a sample of healthy volunteers from western Turkey, including 1063 healthy Turkish controls. Analysis of the ACE I/D gene polymorphisms by polymerase chain reaction found frequencies of 16.1% for the II genotype, 47.7% for the ID genotype, and 36.2% for the DD genotype. The allele frequency was 39.9% for the I alleles and 60.1% for the D allele. This study demonstrates that the allele and genotype frequency values for the Turkish population are similar to previously published frequencies for Caucasian populations.

Use of ACE inhibitors and risk of community-acquired pneumonia: a review

BACKGROUND

The administration of angiotensin-converting enzyme (ACE) inhibitors has been suggested as an alternative strategy for lowering the risk of community-acquired pneumonia (CAP) in the elderly, especially in patients with neurological and cerebrovascular comorbidity.

METHODS

We critically examined the relevant data from studies regarding the impact of ACE inhibitors in lowering the risk of CAP and/or mortality due to CAP in the elderly. We searched PubMed, Cochrane Database, and references of initially retrieved articles, and http://clinicaltrials.gov for ongoing trials.

RESULTS

We identified 285 evaluable studies. Fourteen studies met the inclusion criteria and were evaluated further, of which seven were prospective studies, two randomized controlled trials, and five retrospective studies. Eight of ten studies including patients of Asian origin demonstrated a statistical significance in favor of ACE inhibitors. On the contrary, only one of five studies including patients of non-Asian origin demonstrated results in favor of ACE inhibitors.

CONCLUSION

The available data suggest that ACE inhibitors may contribute to the reduction of the risk of CAP. Nevertheless, clinical data are scarce and mainly comprise studies including patients of Asian origin. As there seem to be differences regarding the genetic polymorphism of ACE among patients of different origins, future studies are needed that incorporate relevant genetics data that may help clarify the role, if any, of ACE inhibitors in preventing CAP.

Role of angiotensin-converting enzyme gene polymorphisms in children with sepsis and septic shock

BACKGROUND

Sepsis is characterized by a systemic inflammatory response. Its development and outcome are associated with host defense, pathogenicity of the microorganism and genetic polymorphisms. Genetic polymorphisms of the immune system genes have been shown to have a close relationship with the clinical outcomes of sepsis. Angiotensin-converting enzyme (ACE) plays a major role in the host defense against invading pathogens. It is therefore likely that polymorphisms in the ACE gene may have an important effect on determining the development and the outcome of sepsis.

METHODS

Ninety-eight children diagnosed as having sepsis and 287 healthy children were included in the study. Insertion/deletion polymorphisms were analyzed using reverse-hybridization assay.

RESULTS

The carriers of I allele (D/I genotype and I/I genotype) were found to have an increased risk of developing sepsis compared to the controls.

CONCLUSION

DD genotype may play a positive role against the development of sepsis in healthy children.

The angiotensin converting enzyme insertion/deletion polymorphism and differences in fasting plasma glucose in Hindustani Surinamese, African Surinamese and ethnic Dutch: the population-based SUNSET-study

We investigated the association between the angiotensin converting enzyme (ACE) insertion/deletion polymorphism and glycemic state. Diabetes mellitus, impaired fasting glucose and mean fasting glucose were not associated with genotype among Hindustani Surinamese, African Surinamese and Dutch participants. Our results cast (further) doubts on the association between ACE and glycemic state.

Angiotensin-converting enzyme insertion/deletion polymorphism and risk and outcome of pneumonia

BACKGROUND

Recent studies have suggested involvement of the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism in the susceptibility to and severity of community-acquired pneumonia (CAP) in Asian populations. We have explored the hypothesis that the ACE I/D polymorphism affects the risk and outcome of CAP in a Dutch white population.

METHODS

This is a hospital-based prospective observational study including patients with CAP admitted between October 2004 and August 2006. All patients were genotyped, and pneumonia severity and clinical outcome were compared between patients with II, ID, and DD genotypes of the ACE gene. Pneumonia severity was assessed on day of hospital admission and consecutively on days 2, 3, 5, and 10 of hospital stay using the acute physiology score (APS). Outcomes evaluated were duration of hospital stay, ICU admittance, and in-hospital and 28-day mortality rates. To study the association between ACE genotype and risk of pneumonia, the distribution of the ACE I/D polymorphism was compared with healthy control subjects from the same geographic region.

RESULTS

In total, 200 patients with pneumonia and 200 control subjects were included in the study. Mean age of the patients was 63 years. APS scores were not different between the genotype groups on any of the days, and all clinical outcomes (duration of hospital stay, ICU admittance, in-hospital and 28-day mortality rates) were comparable between the three genotype groups. The ACE I/D genotype distribution was identical for patients and control subjects (p = 0.973).

CONCLUSIONS

The ACE I/D polymorphism is not associated with risk and outcome of CAP in the Dutch white population.

Polymorphisms of angiotensinogen and angiotensin-converting enzyme associated with lower extremity arterial disease in the Health, Aging and Body Composition study

The role of renin-angiotensin system (RAS) genes on the risk of lower extremity arterial disease (LEAD) in elderly people remains unclear. We assessed the relationship of genetic polymorphisms in RAS: G-6A, T174M and M235T of the angiotensinogen (AGT) gene, and the angiotensin-converting enzyme insertion/deletion (ACE_I/D) variant to the risk of LEAD in the Health, Aging and Body Composition (Health ABC) Study. This analysis included 1228 black and 1306 white men and women whose age ranged between 70 and 79 years at the study enrollment. LEAD was defined as ankle-arm index (AAI) <0.9. Genotype-phenotype associations were estimated by regression analyses with and without adjustment for established cardiovascular disease (CVD) risk factors. The proportion of LEAD was significantly higher in black (21.1%) than that in white elderly people (10.1%, P<0.0001). The distribution of AGT polymorphisms was also significantly different between black and white participants. There was no statistically significant association between the selected RAS genetic variants and LEAD after adjustment for age, antihypertensive medications, lipid-lowering medication, pack-year smoking, body mass index, low-density lipoprotein cholesterol, and prevalent diabetes and coronary heart disease. However, A-T haplotype of G-6A and M235T interacting with homozygous ACE_II (beta=-1.07, P=0.006) and with ACE inhibitors (beta=-1.03, P=0.01) significantly decreased the risk of LEAD in white but not in black participants after adjustment for the selected CVD risk factors. In conclusion, the study observed a gene-gene and gene-drug interaction for LEAD in the white elderly.

The impact of ACE genotype on serum ACE activity in a black South African male population

The strong association between the angiotensin I-converting enzyme (ACE) gene I/D polymorphism with serum ACE activity appears lacking in Nigerians and Kenyans, but has not previously been well assessed in others of African origin. This study addressed this issue in an ethnically well defined black South African population. A putative association for the A22982G ACE gene variant, a QTL likely to impact on serum ACE activity, was also sought. Subjects were 200 healthy male black South African volunteers from the Xhosa ethnic group. Venous blood was obtained from all subjects for DNA extraction. ACE I/D and A22982G genotypes were determined and serum ACE activity measured. Age and blood pressure were recorded. For the group as a whole (mean +/- SD age 38.5 +/- 9.8 years, SBP 119.6 +/- 14.1 mmHg, DBP 78.2 +/- 10.1 mmHg) serum ACE activity was 38.2 +/- 11.2 nmol ml(-1)min(-1). ACE I/D genotype was not significantly associated with serum ACE activity. In contrast, the A22982G variant was significantly associated with serum ACE activity, being 35.9 +/- 9.6, 38.1 +/- 10.6 and 42.4 +/- 15.3 nmol ml(-1)min(-1) for AA, AG and GG genotypes respectively; p = 0.03 by ANOVA and p = 0.01 by linear trend. In keeping with the findings in some other African populations, the ACE I/D polymorphism is not strongly associated with serum ACE activity in Xhosa South Africans. As such, it cannot be used as a marker of ACE activity in these subjects. In this regard the use of the A22982G gene variant may be more appropriate.

Interaction of angiotensin I-converting enzyme insertion-deletion polymorphism and daily salt intake influences hypertension in Japanese men

The contribution of angiotensin I-converting enzyme insertion-deletion polymorphism (ACE I/D) to salt-sensitivity hypertension has been extensively studied by means of salt-loading tests, but whether or not the interaction with daily salt intake affects blood pressure still remains to be clarified. We therefore conducted a cross-sectional study of 284 Japanese male workers (age range, 20-64 years) to examine the effect of ACE I/D genotype and daily salt intake on hypertension. Blood pressure was measured and the ACE I/D was identified by polymerase chain reaction (PCR). Daily salt intake was calculated from a food frequency questionnaire (FFQ). In multivariate analyses, we explored the interaction of ACE I/D and salt intake by means of logistic regression analysis and multiple linear regression analysis. ACE I/D per se was not associated with blood pressure levels or hypertension. ACE I/D interacted with daily salt intake and correlated with hypertension (p for interaction = 0.047). In the ID+II genotype, hypertension was increased by high salt intake (p = 0.005), while in the DD genotype it was not (p = 0.257). The interaction was more prominent in the overweight group (p = 0.039) than in non-overweight group. In the overweight group, high salt intake induced a 10.5 mmHg higher diastolic blood pressure in the ID+II genotype than in the DD genotype (p = 0.042). Our results suggest that ACE I/D and daily salt intake constitute a gene-environment interaction, which may be further modulated by overweight.

Angiotensin-converting enzyme inhibitor use and protection against pneumonia in patients with diabetes

OBJECTIVES

Because of the high risk of pneumonia in patients with diabetes, we aimed to assess the effect of angiotensin-converting enzyme (ACE) inhibitor use on the occurrence of pneumonia in a general population of patients with diabetes.

METHODS

The study population comprised all patients in the UK General Practice Research Database who had a diagnosis of diabetes (both type 1 and type 2) between 1987 and 2001. Cases were defined as patients with a first diagnosis of pneumonia. For each case, up to four controls were matched by age, gender, practice, and index date. Patients were classified as current ACE inhibitor user when the index date was between the start and end date of ACE inhibitor therapy. Conditional logistic regression analysis was used to estimate the strength of the association between ACE inhibitor use and pneumonia risk.

RESULTS

ACE inhibitors were used in 12.7% of 4719 cases and in 13.7% of 15,322 matched controls [crude odds ratio (OR)=0.92, 95% confidence interval (CI)=0.82-1.01]. After adjusting for confounding, ACE inhibitor therapy was associated with a significant reduction in pneumonia risk (adjusted OR=0.72, 95% CI=0.64-0.80). The protective association was consistent across different relevant subgroups with the strongest association in patients with a history of stroke. There was a significant dose-effect relationship (P for trend < 0.001).

CONCLUSIONS

The use of ACE inhibitors is associated with a significant reduction in pneumonia risk and, apart from blood pressure-lowering properties, may be useful in the prevention of pneumonia in patients with diabetes.

ACE I/D polymorphism study in a Cuban hypertensive population

BACKGROUND

The angiotensin converting enzyme (ACE) is a key protein of the renin angiotensin system, whose main function is the conversion of angiotensin I to II. ACE is involved in the physiological control of blood pressure and it is a candidate gene for essential hypertension in humans. We tested the relevance of the ACE insertion/deletion (I/D) polymorphism in our population.

METHODS

We recruited 243 hypertensive and 407 normotensive subjects in the city of Havana, matched according to age, sex and ethnic group. The ACE (I/D) polymorphism was determined by the polymerase chain reaction (PCR) technique. The fit of genotype frequencies to Hardy-Weinberg proportions was evaluated in all groups analyzed. The possible association between the ACE I/D polymorphism and hypertension status was tested by chi2 and odds ratio tests.

RESULTS

All groups but black female cases were in Hardy-Weinberg equilibrium. The frequencies of the D allele in hypertensive/normotensive subjects were 0.61/0.59 in white males, 0.58/0.58 in white females, 0.47/0.59 in black males and 0.58/0.54 in black females. The distribution of ACE genotypes differed significantly between cases and controls only in black women according to the additive model (chi2p=0.04) but the adjusted OR did not show significant association (OR 1.14 95% CI 0.62 to 2.10).

CONCLUSION

The ACE I/D polymorphism was not associated with hypertension in our multiethnic sample. While the chi2 test for additive model in black women suggested a marginal significance, the adjusted OR did not show any significant association.

Association of the C-344T polymorphism of CYP11B2 gene with essential hypertension in Hani and Yi minorities of China

BACKGROUND

Aldosterone synthase (CYP11B2) is a key enzyme in the biosynthesis of aldosterone. Recently, a C-344T polymorphism in the promoter region of the CYP11B2 gene has been reported to be in association with high blood pressure. We investigated the association between this polymorphism and essential hypertension in Hani (n=305 individuals) and Yi (n=233 individuals) minorities of China.

METHODS

CYP11B2 genotyping with polymerase chain reaction-restriction fragment length polymorphism was performed in 267 normotensive subjects and 271 essential hypertensive subjects. At the same time, the T(-344)C polymorphism detection in 33 subjects was also performed by sequencing.

RESULT

The frequency of CYP11B2 C-344T genotype in normotensive controls and essential hypertensive cohort in Hani population were TT: 0.729 vs. 0.610; CT + CC: 0.271 vs. 0.390, respectively. The frequency of CYP11B2 C-344T genotype in normotensive controls and essential hypertensive cohort in Yi population were TT: 0.612 vs. 0.475; CT + CC: 0.388 vs. 0.525, respectively. The frequency of CC + CT genotype in the essential hypertensive group was significantly higher than that in the normotensive controls in both Hani and Yi populations (P<0.05).

CONCLUSION

The -344C allele of the CYP11B2 may play a role in genetic predisposition to developing essential hypertension in Hani and Yi minorities of China.

Adjusting for treatment effects in studies of quantitative traits: antihypertensive therapy and systolic blood pressure

A population-based study of a quantitative trait may be seriously compromised when the trait is subject to the effects of a treatment. For example, in a typical study of quantitative blood pressure (BP) 15 per cent or more of middle-aged subjects may take antihypertensive treatment. Without appropriate correction, this can lead to substantial shrinkage in the estimated effect of aetiological determinants of scientific interest and a marked reduction in statistical power. Correction relies upon imputation, in treated subjects, of the underlying BP from the observed BP having invoked one or more assumptions about the bioclinical setting. There is a range of different assumptions that may be made, and a number of different analytical models that may be used. In this paper, we motivate an approach based on a censored normal regression model and compare it with a range of other methods that are currently used or advocated. We compare these methods in simulated data sets and assess the estimation bias and the loss of power that ensue when treatment effects are not appropriately addressed. We also apply the same methods to real data and demonstrate a pattern of behaviour that is consistent with that in the simulation studies. Although all approaches to analysis are necessarily approximations, we conclude that two of the adjustment methods appear to perform well across a range of realistic settings. These are: (1) the addition of a sensible constant to the observed BP in treated subjects; and (2) the censored normal regression model. A third, non-parametric, method based on averaging ordered residuals may also be advocated in some settings. On the other hand, three approaches that are used relatively commonly are fundamentally flawed and should not be used at all. These are: (i) ignoring the problem altogether and analysing observed BP in treated subjects as if it was underlying BP; (ii) fitting a conventional regression model with treatment as a binary covariate; and (iii) excluding treated subjects from the analysis. Given that the more effective methods are straightforward to implement, there is no argument for undertaking a flawed analysis that wastes power and results in excessive bias.

Genes and human elite athletic performance

Physical fitness is a complex phenotype influenced by a myriad of environmental and genetic factors, and variation in human physical performance and athletic ability has long been recognised as having a strong heritable component. Recently, the development of technology for rapid DNA sequencing and genotyping has allowed the identification of some of the individual genetic variations that contribute to athletic performance. This review will examine the evidence that has accumulated over the last three decades for a strong genetic influence on human physical performance, with an emphasis on two sets of physical traits, viz. cardiorespiratory and skeletal muscle function, which are particularly important for performance in a variety of sports. We will then review recent studies that have identified individual genetic variants associated with variation in these traits and the polymorphisms that have been directly associated with elite athlete status. Finally, we explore the scientific implications of our rapidly growing understanding of the genetic basis of variation in performance.

Association between the angiotensin-converting enzyme gene insertion/deletion polymorphism and essential hypertension in young Pakistani patients

Several studies have demonstrated the importance of angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphisms in the pathogenesis of hypertension. This study sought to determine the association between the ACE I/D polymorphism and essential hypertension in young Pakistanis. The frequency of the ACE I/D polymorphism was established by a comparative cross-sectional survey of Pakistani patients suffering from essential hypertension and ethnically matched normotensive controls. Samples were collected from tertiary care hospitals in northern Pakistan. Hypertensive individuals were defined as those with a systolic blood pressure > 140 mmHg and/or diastolic blood pressure > 90 mmHg on three separate occasions, or those currently receiving one, or more, anti-hypertensive agents. DNA samples obtained from hypertensive (n = 211) and normotensive (n = 108) individuals were typed by PCR. The frequency of the ACE I/I genotype was significantly higher in hypertensive patients, aged 20-40 years, than in normotensive controls of the same age group (chi(2) = 4.0, P = 0.041). Whereas no overall significant differences were observed between the I/I, I/D and D/D ACE genotypes (One way ANOVA, F = 0.672; P = 0.413). The association between the ACE I/I genotype and essential hypertension in individuals aged </= 40 years suggests that ACE has a role in early onset essential hypertension in Pakistan.

ACE insert/delete polymorphism and atherosclerosis

We report on the results of a large autopsy study focusing upon the hypothesis that deletion of the Alu insert in the angiotensin converting enzyme (ACE) gene is associated with: (a) greater prevalence or extent of atherosclerosis in the aorta and coronary arteries; and (b) microscopic qualities of established atherosclerotic plaques in the coronary arteries. This study was conducted in young US black (n=290) and white (n=379) males using available materials and data from the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study, a multi-center cooperative autopsy study organized in 1985 to explore the relationships of known cardiovascular risk factors to atherosclerosis in victims of accidents, homicides, or suicides in the age range of 15-34 years. The results provide strong evidence that ACE genotype may not be a predictor of either the prevalence or the extent of the lesions of atherosclerosis in the right coronary artery or the aorta of young adults, an observation that confirms previous studies that estimated the prevalence and extent of atherosclerosis using coronary angiography. In addition, the results suggest that ACE genotype does not contribute to the formation of atherosclerotic lesions that have the characteristics of vulnerable plaques in the left anterior descending coronary artery of young adults.

Circulating soluble E-selectin levels and the Ser 128Arg polymorphism in individuals from different ethnic groups

BACKGROUND AND AIM

An association between the Ser128 Arg polymorphism and coronary heart disease (CHD) has been previously demonstrated in a white population. The aim of this study was to investigate whether the Ser128 Arg polymorphism of the E-selectin gene is associated with soluble E-selectin levels in individuals from a multiethnic population.

METHODS AND RESULTS

Plasma sE-selectin levels and the Ser128 Arg E-selectin gene polymorphism were determined in 244 white (109 females), 176 of African origin (90 females) and 208 South Asian (95 females) healthy individuals living in England selected from the Wandsworth Heart and Stroke Study (WHSS). The substitution of serine for arginine (A to C mutation) was more common in whites (9.6%) and South Asians (7.9%) compared to the people of African origin (3.7%); p=0.005. The C mutation had no effect on sE-selectin levels in any ethnic group.

CONCLUSIONS

We found a lower frequency of this polymorphism in the people of African origin who have a low CHD risk. However, in this study the polymorphism was not associated with circulating sE-selectin levels. Whether it plays a role in determining ethnic differences in vascular disease via a mechanism affecting leukocyte recruitment remains to be determined.

ACE genotype and cognitive decline in an African-Caribbean population

The insertion/deletion (I/D) polymorphism of the angiotensin I converting enzyme (ACE) gene is believed to influence risk of cerebrovascular disease. However, associations with cognitive outcomes remain controversial. As far as we are aware, all studies to date have been carried out in white American or European populations. African-Caribbean populations have high prevalence rates of hypertension, diabetes and cerebrovascular disease but risk factors for cognitive outcomes remain under-researched. In a UK community sample of 148 African-Caribbean people aged 55-75 years, we investigated the association between ACE genotype and cognitive decline over 3 years using a battery of repeated tests. No direct association was found between ACE genotype and decline. However, the association between increased age and cognitive decline was significantly stronger in people with the ACE DD genotype (odds ratio 3.6 per 5-year increase, 95% CI: 1.9-6.7) compared to those with ID/II genotype (odds ratio 0.7, 95% CI 0.4-1.2). This interaction was particularly strong for decline in verbal memory and was not apparently mediated by vascular risk factors measured at baseline.