Is the influence of variation in the ACE gene on the prospective risk of Type 2 diabetes in middle-aged men modified by obesity?

Clinical Utility of Amplification Refractory Mutation System-Based PCR and Mutation-Specific PCR for Precise and Rapid Genotyping of Angiotensin-Converting Enzyme 1 (ACE1-rs4646996 D>I) and Angiotensin-Converting Enzyme 2 (ACE2-rs4240157T>C) Gene Variations in Coronary Artery Disease and Their Strong Association with Its Disease Susceptibility and Progression

Background: Experimental clinical and research studies demonstrated that the renin−angiotensin system (RAS) affects the pathogenesis of atherosclerosis and the prognosis of coronary heart disease (CHD). The results show that ACE2 (angiotensin I-converting enzyme 2) might act as a protective protein for cardiovascular diseases; however, only a few studies in human populations have been carried out. The aim of this study was to develop, optimize, and validate a direct T-ARMS-based PCR assay for the precise and rapid genotyping of ACE1-rs4646996 D>I and ACE2-rs4240157T>C and study their association with coronary artery disease susceptibility and progression. Methodology: This study included 149 consecutive coronary artery disease patients and 150 healthy controls. We utilized T-ARMS for the precise and rapid genotyping of ACE2-rs4240157; rs4646994. Results: Our results indicated that the ACE1-rs4646996 D>I genotypes observed between CAD cases and controls were statistically significant (p < 0.008) and, similarly, the ACE2-rs4240157T>C genotypes observed were significant (p < 0.0001). Moreover, the frequency of the D allele (ACE1-D>I) and C allele (ACE2-rs4240157T>C) was found to be higher among CAD patients than the HC. Our results indicated that in the codominant model, the ACE2-ID genotype was strongly associated with increased CAD susceptibility in a codominant model with an OR of 2.37, (95%) CI = (1.023−5.504), and p < 0.04. Similarly, the ACE2-DD genotype was strongly associated with an increased CAD susceptibility with an OR of 3.48, (95%) CI = (1.49 to 8.117), and p < 0.003. Similarly, in allelic comparison, the D allele was strongly associated with CAD susceptibility with an OR of 1.59, (95%) CI = (1.12−2.24), and p < 0.003. Our results revealed that there was a significant correlation between ACE2-I/D genotypes and hypertension, T2D, and obesity (p < 0.05). The results of ACE2 rs4240157 genotyping indicated a strong association in the codominant model with an increased CAD susceptibility with an OR of 3.62, (95%) CI = (2.027 to 6.481), and p < 0.0001. Similarly, in a dominant inheritance model, a strong association is observed between the ACE2 rs4240157 (CT+CC) genotype with an OR of 6.34, (95%) CI = (3.741 to 10.749), and p < 0.0001. In allelic comparison, the T allele was strongly associated with CAD susceptibility with an OR of 5.56, (95% CI = (3.56 to 7.17), and p < 0.0001. Similarly, our results revealed that there was a significant association of the ACE2-rs4240157T>C genotypes with Triglycerides (mg/dL), HDL-C (mg/dL), total Cholesterol (mg/dL), and C-reactive protein (mg/L) in CAD. Conclusion: It was indicated that the ARMS technique and MS-PCR assay proved to be fast, accurate, and reliable for ACE2-rs4240157T>C and ACE1-rs4646996 D>I, respectively, and can be used as a potential molecular tool in the diagnosis of genetic diseases in undeveloped and developing countries—where there might be a shortage of medical resources and supplies. ACE1-I>D genotypes were strongly associated with T2D, hypertension, and obesity (p < 0.002). Besides the ACE2-rs4240157 CT heterozygosity genotype, the T allele was strongly associated with CAD susceptibility. Future longitudinal studies in different ethnic populations with larger sample sizes are recommended to validate these findings

A comparison of a ketogenic diet with a LowGI/nutrigenetic diet over 6 months for weight loss and 18-month follow-up

BACKGROUND

Obesity and its related metabolic disturbances represent a huge health burden on society. Many different weight loss interventions have been trialled with mixed efficacy, as demonstrated by the large number of individuals who regain weight upon completion of such interventions. There is evidence that the provision of genetic information may enhance long-term weight loss, either by increasing dietary adherence or through underlying biological mechanisms.

METHODS

The investigators followed 114 overweight and obese subjects from a weight loss clinic in a 2-stage process. 1) A 24-week dietary intervention. The subjects self-selected whether to follow a standardized ketogenic diet (n = 53), or a personalised low-glycemic index (GI) nutrigenetic diet utilising information from 28 single nucleotide polymorphisms (n = 61). 2) After the 24-week diet period, the subjects were monitored for an additional 18 months using standard guidelines for the Keto group vs standard guidelines modified by nutrigenetic advice for the low-Glycaemic Index nutrigenetic diet (lowGI/NG) group.

RESULTS

After 24 weeks, the keto group lost more weight: - 26.2 ± 3.1 kg vs - 23.5 ± 6.4 kg (p = 0.0061). However, at 18-month follow up, the subjects in the low-GI nutrigenetic diet had lost significantly more weight (- 27.5 ± 8.9 kg) than those in the ketogenic diet who had regained some weight (- 19.4 ± 5.0 kg) (p < 0.0001). Additionally, after the 24-week diet and 18-month follow up the low-GI nutrigenetic diet group had significantly greater (p < 0.0001) improvements in total cholesterol (ketogenic - 35.4 ± 32.2 mg/dl; low-GI nutrigenetic - 52.5 ± 24.3 mg/dl), HDL cholesterol (ketogenic + 4.7 ± 4.5 mg/dl; low-GI nutrigenetic + 11.9 ± 4.1 mg/dl), and fasting glucose (ketogenic - 13.7 ± 8.4 mg/dl; low-GI nutrigenetic - 24.7 ± 7.4 mg/dl).

CONCLUSIONS

These findings demonstrate that the ketogenic group experienced enhanced weight loss during the 24-week dietary intervention. However, at 18-month follow up, the personalised nutrition group (lowGI/NG) lost significantly more weight and experienced significantly greater improvements in measures of cholesterol and blood glucose. This suggests that personalising nutrition has the potential to enhance long-term weight loss and changes in cardiometabolic parameters.

TRIAL REGISTRATION

NCT04330209, Registered 01/04/2020, retrospectively registered.

Is diet partly responsible for differences in COVID-19 death rates between and within countries?

Reported COVID-19 deaths in Germany are relatively low as compared to many European countries. Among the several explanations proposed, an early and large testing of the population was put forward. Most current debates on COVID-19 focus on the differences among countries, but little attention has been given to regional differences and diet. The low-death rate European countries (e.g. Austria, Baltic States, Czech Republic, Finland, Norway, Poland, Slovakia) have used different quarantine and/or confinement times and methods and none have performed as many early tests as Germany. Among other factors that may be significant are the dietary habits. It seems that some foods largely used in these countries may reduce angiotensin-converting enzyme activity or are anti-oxidants. Among the many possible areas of research, it might be important to understand diet and angiotensin-converting enzyme-2 (ACE2) levels in populations with different COVID-19 death rates since dietary interventions may be of great benefit.

Ethnic differences in the association between angiotensin-converting enzyme gene insertion/deletion polymorphism and peripheral vascular disease: A meta-analysis

Background

Several studies have investigated the association of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism with peripheral vascular disease (PVD); however, the results remain controversial. Therefore, we conducted the current meta-analysis to evaluate this relationship in the general population of different ethnicities.

Methods

We searched PubMed, Embase, Web of Science, Wanfang Database, and CNKI to identify eligible studies. Random-effect models were applied to estimate the pooled odds ratio (OR) with a 95% confidence interval (CI), regardless of between-study heterogeneity.

Results

A total of 13 studies with 1966 cases and 6129 controls were included in this meta-analysis. The pooled ORs for the association between ACE I/D polymorphism and PVD risk were not statistically significant in the overall population under all genetic models. In further ethnicity-stratified analyses, we found a statistically significant association of ACE I/D polymorphism with PVD susceptibility in Asians under most models. However, the association among Caucasians did not reach statistical significance.

Conclusion

ACE I/D polymorphism might be associated with susceptibility to PVD in the Asian population, but there was no clear evidence indicating a similar significant relationship among Caucasians.

Angiotensin-converting enzyme insertion/deletion polymorphism association with obesity and some related disorders in Egyptian females: a case-control observational study

BACKGROUND

According to the WHO report in 2015, obesity is the fifth leading cause of death worldwide, and the prevalence of Egyptian female obesity is 37.5 %. Since obesity is highly influenced by genetics, and adipose tissue renin-angiotensin system is over-activated in obesity, the effect of angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism on obesity and related disorders was studied in several populations, because of its effect on ACE activity. Our objective was to study the association of ACE I/D polymorphism with obesity and certain related disorders, namely hypertension, insulin resistance and metabolic syndrome, in Egyptian females.

METHODS

Eighty female volunteers were recruited, blood pressure and body measurements were recorded and a fasting blood sample was obtained for the quantitation of glucose, lipid profile, insulin, leptin and identification of ACE I/D polymorphs. Subjects were grouped based on hypertension and obesity states. Comparisons of continuous parameters were made with independent sample t-test between two groups. The frequencies of ACE genotypes and alleles, and the association between gene polymorphism and metabolic parameters were assessed using chi-square or Fisher's exact test.

RESULTS

Genotype frequencies were in Hardy-Weinberg equilibrium for all groups. Genotype distribution did not differ significantly between controls and cases of all the studied disorders. Although DD carriers had apparently higher parameters of blood pressure, lipid profile and insulin resistance, only diastolic blood pressure was almost significant (p = 0.057). I-carriers were significantly less susceptible to hypertension than DD carriers having normal waist/hip ratio (p = 0.007, OR = 17.29, CI = 1.81-164.96) and normal conicity index (p = 0.024, OR = 7.00, CI = 1.36-35.93). In DD genotype carriers, a significant association was found between insulin resistance and high body mass index (p = 0.004, OR = 8.89, CI = 1.94-40.71), waist circumference (p = 0.003, OR = 9.63, CI = 2.14-43.36) and waist/height ratio (p = 0.034, OR = 6.86, CI = 1.25-37.61), although the variations in percentages between DD and I-carriers were not high enough to conclude an effect of ACE I/D on such an association.

CONCLUSIONS

In this sample of Egyptian females, ACE I/D polymorphism was not significantly associated with obesity nor with any of its related disorders studied. The I allele seemed protective against hypertension in subjects with normal, not high, waist/hip ratio and conicity index compared to DD genotype carriers.

Association of angiotensin I converting enzyme, angiotensin II type 1 receptor and angiotensin I converting enzyme 2 gene polymorphisms with the dyslipidemia in type 2 diabetic patients of Chinese Han origin

OBJECTIVE

To investigate whether the genetic polymorphisms in the angiotensin I converting enzyme (ACE) (insertion/ deletion, or I/D), angiotensin II type 1 receptor (AT1R) (rs5186), and ACE2 (rs2285666) could be associated with dyslipidemia in Type 2 diabetic (T2D) patients of Chinese Han origin.

DESIGN AND METHODS

The above 3 polymorphisms were genotyped in a total of 282 patients with T2D and dyslipidemia (Group A), 182 patients with T2D but without dyslipidemia (Group B), and 324 healthy controls. The association between a certain polymorphism and each group was assessed by an odds ratio (OR).

RESULTS

The D allele of the ACE (I/D) was significantly associated with the risk of T2D accompanying dyslipidemia between group A and controls [OR=1.37, 95% confidence interval (CI)=1.08-1.74; p=0.010], and significant association of the D allele with dyslipidemia was also observed in diabetic patients (OR=1.88, 95% CI=1.40-2.54; p<0.001). Furthermore, the ID genotype had a decreased risk of developing T2D without dyslipidemia as compared with controls (OR=0.52, 95% CI=0.32-0.82; p=0.0060). The distributions of the AT1R (rs5186) and ACE2 (rs2285666) genotypes and alleles did not differ between T2D patients with or without dyslipidemia and the controls.

CONCLUSIONS

This study demonstrates that the ACE (I/D) polymorphism is associated with T2D, regardless of the absence or presence of dyslipidemia. The polymorphisms in the AT1R (rs5186) and ACE2 (rs2285666) seem to play lesser roles in the development of T2D.

Heritability of insulin sensitivity and lipid profile depend on BMI: evidence for gene-obesity interaction

AIMS/HYPOTHESIS

Evidence from candidate gene studies suggests that obesity may modify genetic susceptibility to type 2 diabetes and dyslipidaemia. On an aggregate level, gene-obesity interactions are expected to result in different heritability estimates at different obesity levels. However, this hypothesis has never been tested.

METHOD

The present study included 2,180 British female twins. BMI was used as an index of general obesity. Outcome measures were insulin sensitivity (indexed by quantitative insulin-sensitivity check index [QUICKI]) and fasting plasma lipid profile. Structural equation modelling was used to test whether BMI interacted with latent genetic and environmental effects to impact on the outcome measures.

RESULTS

Genetic influences on triacylglycerol increased with BMI (p < 0.001) whereas the unique environmental influence on QUICKI decreased with BMI (p < 0.001), resulting in a higher heritability estimate for both measures at higher BMI levels. This was further illustrated by stratified analysis in twin pairs concordant for normal weight and twin pairs concordant for overweight. Heritability was 19 percentage points higher for triacylglycerol (p < 0.001) and 31 percentage points higher for QUICKI (p < 0.01) among twins concordant for overweight than among twins concordant for normal weight. BMI had no moderator effect on the latent genetic and environmental factors for total cholesterol and HDL-cholesterol.

CONCLUSIONS/INTERPRETATION

Our results suggest that the expression of genes influencing triacylglycerol and insulin sensitivity can vary as a function of obesity status. The substantial increases in the genetic contribution to the total variance in insulin sensitivity and triacylglycerols at higher BMIs may prove extremely valuable in the search for candidate genes.

Genotype-phenotype associations: modulation by diet and obesity

Changes in diet are likely to reduce chronic disorders, but after decades of active research and heated discussion, the question still remains: what is the optimal diet to achieve this elusive goal? Is it a low-fat diet, as traditionally recommended by multiple medical societies? Or a high monounsaturated fat (MUFA) diet as predicated by the Mediterranean diet? Perhaps a high polyunsaturated fat (PUFA) diet based on the cholesterol-lowering effects? The right answer may be all of the above but not for everybody. A well-known phenomenon in nutrition research and practice is the dramatic variability in interindividual response to any type of dietary intervention. There are many other factors influencing response, and they include, among many others, age, sex, physical activity, alcohol, and smoking as well as genetic factors that will help to identify vulnerable populations/individuals that will benefit from a variety of more personalized and mechanistic-based dietary recommendations. This potential could and needs to be developed within the context of nutritional genomics that in conjunction with systems biology may provide the tools to achieve the holy grail of dietary prevention and therapy of chronic diseases and cancer. This approach will break with the traditional public health approach of "one size fits all." The current evidence based on nutrigenetics has begun to identify subgroups of individuals who benefit more from a low-fat diet, whereas others appear to benefit more from high MUFA or PUFA diets. The continuous progress in nutrigenomics will allow some time in the future to provide targeted gene-based dietary advice.