Plasma Kallikrein and Angiotensin I-converting enzyme N- and C-terminal domain activities are modulated by the insertion/deletion polymorphism

The frequency of the ACE I/D polymorphism in South America: a systematic review and meta-analysis

Angiotensin-converting enzyme (ACE) is a key component of the renin-angiotensin system and plays an important role in homeostasis and maintenance of blood pressure. However, little is known about allele and genotypic frequencies, as well as phenotypic characteristics associated with ACE polymorphism genotypes in South American populations. This study aimed to verify the allelic predominance and genotype frequency of ACE I/D polymorphism in South America and its association with the main diseases and related conditions. We conducted a systematic review considering studies published in the last 25 years available in PubMed, Scielo, LILACS, LIPECS, Coleciona SUS, CUMED, BINACIS, IBECS, and MEDLINE databases, resulting in the inclusion of 121 studies. Quality of the studies was assessed according to the Strengthening the Reporting of Genetic Association (STREGA) guidelines. We mapped the frequency of the ACE I/D polymorphism in South American populations. 8,856 (32.1%) subjects were DD, 13,050 were ID (47.4%), and 5,644 were II (20.5%) carriers. The main associated conditions included systemic arterial hypertension and other cardiovascular conditions, cardiorespiratory or respiratory characteristics, physical activity level, kidney conditions, aging-related diseases, as well as different types of cancers and metabolic conditions. 61.1% of the studies found no significant association between the respective conditions investigated and the ACE I/D polymorphism. Considering DD genotype or D allele, 21.5% of the studies observed negative and 4.9% positive outcomes. Regarding ID genotype, 4.1% of the studies identified negative and 0.8% positive outcomes, and for II genotype or I allele, 4.1% of the results had negative and 10.7% positive associations.

ACE I/D polymorphism is a risk factor for the clinical severity of COVID-19 in Brazilian male patients

BACKGROUND

The renin-angiotensin system is potentially involved in the pathogen-host interaction in the disease caused by SARS-CoV-2, since the angiotensin-converting enzyme (ACE) 2 serves as a receptor for the virus. The impact of the pandemic in specific regions and ethnic groups highlights the importance of investigating genetic factors that disrupt the balance of the system in response to SARS-CoV-2 infection, especially in genes with ethnic frequency variations. Therefore, this study aimed to evaluate the influence of the ACE I/D polymorphism on the incidence and severity of COVID-19 in a sample of the Brazilian population.

METHODS AND RESULTS

70 severe cases and 355 mild cases patients were evaluated. DNA extraction was performed using a QIAamp DNA Blood Mini kit. Genotyping of ACE I/D polymorphism was performed. Clinical outcomes were obtained from the patients' records. We found an association between the ACE I/D polymorphism and the incidence or severity of COVID-19 in male participants. Moreover, we observed a relationship between severity and increasing age and body weight and a higher frequency of II genotype individuals among those who had a cough as their symptoms in mild patients. No differences were observed in leukocyte count or other parameters related to the inflammatory response in severe patients.

CONCLUSIONS

Our data showed the influence of the ACE I/D polymorphism on severity of COVID-19 in males, as well as on the occurrence of cough in patients with mild symptoms, with a higher incidence in those carrying the I allele.

Genetic polymorphisms in the angiotensin converting enzyme, actinin 3 and paraoxonase 1 genes in women with diabetes and hypertension

Objective

To study associations between polymorphisms in the angiotensin converting enzyme (ACE I/D), actinin 3 (ACTN3 R577X) and paraoxonase 1 (PON1 T(-107)C) genes and chronic diseases (diabetes and hypertension) in women.

Materials and methods

Genomic DNA was extracted from saliva samples of 78 women between 18 and 59 years old used for genetic polymorphism screening. Biochemical data were collected from the medical records in Basic Health Units from Southern Brazil. Questionnaires about food consumption, physical activity level and socioeconomic status were applied.

Results

The XX genotype of ACTN3 was associated with low HDL levels and high triglycerides, total cholesterol and glucose levels. Additionally, high triglycerides and LDL levels were observed in carriers of the TT genotype of PON1, and lower total cholesterol levels were associated to the CC genotype. As expected, women with diabetes/hypertense had increased body weight, BMI (p = 0.02), waist circumference (p = 0.01), body fat percentage, blood pressure (p = 0.02), cholesterol, triglycerides (p = 0.02), and blood glucose (p = 0.01), when compared to the control group.

Conclusion

Both ACTN3 R577X and PON1 T(-107)C polymorphisms are associated with nutritional status and blood glucose and lipid levels in women with diabetes/hypertense. These results contribute to genetic knowledge about predisposition to obesity-related diseases.

Metabolomic Profiling of Recombinant Erythropoietin (rHuEpo) in Trained Caucasian Athletes

OBJECTIVE

Recombinant human erythropoietin (rHuEpo) is prohibited by the World Anti-Doping Agency but remains the drug of choice for many cheating athletes wishing to evade detection using current methods. The aim of this study was to identify a robust metabolomics signature of rHuEpo using an untargeted approach in blood (plasma and serum) and urine.

DESIGN

Longitudinal study.

SETTING

University of Glasgow.

PARTICIPANTS

Eighteen male participants regularly engaged in predominantly endurance-based activities, such as running, cycling, swimming, triathlon, and team sports, were recruited.

INTERVENTIONS

Each participant received 50 IU·kg -1 body mass of rHuEpo subcutaneously every 2 days for 4 weeks. Samples were collected at baseline, during rHuEpo administration (over 4 weeks) and after rHuEpo administration (week 7-10). The samples were analyzed using hydrophilic interaction liquid chromatography mass spectrometry.

MAIN OUTCOME MEASURES

Significant metabolic signatures of rHuEpo administration were identified in all biofluids tested in this study.

RESULTS

Regarding metabolomics data, 488 plasma metabolites, 694 serum metabolites, and 1628 urinary metabolites were identified. Reproducible signatures of rHuEpo administration across all biofluids included alterations of pyrimidine metabolism (orotate and dihydroorotate) and acyl-carnitines (palmitoyl-carnitine and elaidic carnitine), metabolic pathways that are associated with erythropoiesis or erythrocyte membrane function, respectively.

CONCLUSIONS

Preliminary metabolic signatures of rHuEpo administration were identified. Future studies will be required to validate these encouraging results in independent cohorts and with orthogonal techniques, such as integration of our data with signatures derived from other "omics" analyses of rHuEpo administration (eg, transcriptomics).

Association between basketball playing position and ACTN3 R577X polymorphism in athletes of first division Brazilian Basketball League

INTRODUCTION

Genetic-association studies have shown that some polymorphisms are associated with different aspects of athletic performance, including very specific features, such as players' position in team sports, like soccer, rugby, and Australian football. However, this type of association has not been investigated in Basketball yet. The present study analyzed the association of ACTN3 R577X, AGT M268T, ACE I/D and BDKRB2+9/-9 polymorphisms with the position of basketball players.

METHODS

One hundred fifty-two male athletes from 11 teams of the first division of Brazilian Basketball League and 154 male Brazilian controls were genotyped. The analyses of the ACTN3 R577X and AGT M268T were performed by the allelic discrimination method, while ACE I/D and BDKRB2+9/-9 by conventional PCR followed by electrophorese in agarose gel.

RESULTS

The results showed a significant effect of height on all positions and an association between the genetic polymorphisms analyzed and basketball positions. In addition, a significantly higher frequency of ACTN3 577XX genotype was observed in Point Guards. Also, compared to Point Guard, ACTN3 RR and RX were more prevalent in the Shooting Guard and Small Forward group and RR genotype was also more prevalent in the Power Forward and Center group.

CONCLUSION

The main finding of our study was the positive association of ACTN3 R577X polymorphism and basketball playing position, and a suggestion of genotypes related to strength/power performance with post players and genotypes related to endurance performance with point guard players.

Angiotensin-converting-enzyme insertion/deletion polymorphism, ACE activity, and COVID-19: A rather controversial hypothesis. A case-control study

Accumulating data has shown a contribution of the renin‐angiotensin system in COVID‐19 pathogenesis. The role of angiotensin‐converting enzyme (ACE) insertion (I)/deletion (D) polymorphism as a risk factor in developing COVID‐19 disease comes from epidemiological data and is controversially discussed. We conducted a retrospective case‐control study and assessed the impact of ACE I/D genotype in COVID‐19 disease prevalence and severity. In 81 COVID‐19 patients explicitly characterized and 316 controls, recruited during the first wave of COVID‐19 pandemic, ACE I/D genotype, and ACE activity were determined. A generalized linear model was used and Poisson regression analysis estimated the risk ratios (RRs) of alleles and genotypes for disease severity. DD patients had almost 2.0‐fold increased risk (RR: 1.886, confidence limit [CL] 95%: 1.266–2.810, p = 0.0018) of developing a more severe disease when contrasted to ID and II individuals, as did D allele carriers compared to I carriers (RR: 1.372; CL 95%: 1.051–1.791; p = 0.0201). ACE activity (expressed as arbitrary units, AU/L) was lower in patients (3.62 ± 0.26) than in controls (4.65 ± 0.13) (p < 0.0001), and this reduction was observed mainly among DD patients compared to DD controls (3.97 ± 0.29 vs. 5.38 ± 0.21; p = 0.0014). Our results demonstrate that ACE DD genotype may predispose to COVID‐19 increased disease severity via a mechanism associated, at least in part, with the significant fall in their ACE activity. Our findings suggest a more complex pattern of synergy between this polymorphism and ACE activity in COVID‐19 patients compared to healthy individuals and set the grounds for large‐scale studies assessing ACE genotype‐based optimized therapies with ACE inhibitors and angiotensin receptor blockers.

Behavioural effects of the ACE insertion/deletion polymorphism in Alzheimer's disease depend upon stratification according to APOE-ϵ4 carrier status

Introduction: The inherited risk of late-onset Alzheimer's disease (AD) is genetically determined. We aimed to examine associations of genetic variants of APOE and ACE with age at AD onset and with neuropsychiatric symptoms according to each dementia stage.Methods: Consecutive outpatients with AD were assessed for demographic features, Clinical Dementia Rating scores, and the 10-item Neuropsychiatric Inventory, and genotyped for rs7412 and rs429358 (APOE haplotypes, Real-Time Polymerase Chain Reactions), and the ACE insertion/deletion polymorphism (Polymerase Chain Reactions). Combined genetic variants of APOE and ACE were associated with age at dementia onset, and with neuropsychiatric symptoms in each dementia stage (adjusted for sex and age at dementia onset).Results: Over two-thirds of the 238 patients were women, whereas the mean age at dementia onset was 73.82 ± 6.2 years-old. APOE-ϵ4/ϵ4 carriers had earlier dementia onset (p<.001). The ACE insertion/deletion polymorphism was in Hardy-Weinberg equilibrium (p=.37) but was not associated with age at dementia onset, regardless of APOE-ϵ4 carrier status. The only results that survived corrections for false discovery rates were higher scores of dysphoria for APOE-ϵ4 carriers (n=122) who also carried ACE deletion/deletion (p=.031). No results survived corrections for false discovery rates for APOE-ϵ4 non-carriers (n=116).Conclusions: Though only the APOE-ϵ4/ϵ4 haplotype affected AD onset, effects of the ACE insertion/deletion polymorphism over behavioural features might differ according to APOE-ϵ4 carrier status in genetic associations.

Previous experience, aerobic capacity and body composition are the best predictors for Olympic distance triathlon performance: Predictors in amateur triathlon

OBJECTIVE

Present study examines predictors of the overall race time and disciplines in the Olympic distance triathlon.

METHODS

Thirty-nine male and six female triathletes were evaluated for anthropometric, physiological, genetic, training, clinical and circadian characteristics. Body composition, maximum capacity for oxygen uptake (V˙O_2max), maximum aerobic velocity (MAV), anaerobic threshold (AT), triathlon experience (TE) and XX genotype for α-actinin 3 affected total race time (p<0.05).

RESULTS

Total race time can be predicted by MAV (ß = -0.430, t = -3.225, p = 0.003), TE (ß = -0.378, t = -3.605, p = 0.001), and percentage of lean mass (%LM) (ß = -0.332, t = -2.503, p = 0.017). Swimming can be predicted by MAV (ß = -0.403, t = -3.239, p = 0.002), TE (ß = -0.339, t = -2.876, p = 0.007), and AT%V˙O_2max (ß = 0.281, t = 2.278, p = 0.028). Cycling can be predicted by MAV (ß = -0.341, t = -2.333, p = 0.025), TE (ß = -0.363, t = -3.172, p = 0.003), and %LM (ß = -0.326, t = -2.265, p = 0.029). In running split, MAV (ß = -0.768, t = -6.222, p < 0.001) was the only parameter present in the best multiple linear regression model.

CONCLUSION

The most important variables in multiple regression models for estimating performance were MAV, TE, AT and %LM.

Pharmacogenetic analyses of variations of measures of cardiovascular risk in Alzheimer's dementia

Background & objectives:

Neurodegeneration affects blood pressure variations, while renal function and cerebral perfusion are impaired by vascular risk factors. This study was aimed to estimate variations of measures of cardiovascular risk in Alzheimer's dementia by pharmacogenetic analyses of the effects of angiotensin-converting enzyme (ACE) inhibitors and statins.

Methods:

Consecutive patients were prospectively followed to study variations of creatinine clearance and blood pressure for one year, estimated by correlating the effects of ACE inhibitors with the ACE Alu I/D polymorphism and genotypes or haplotypes of rs1800764 or rs4291, and the effects of statins with LDLR (low-density lipoprotein receptor) genotypes or haplotypes of rs11669576 (exon 8) or rs5930 (exon 10), or genotypes of rs2695121 (liver X receptor β gene). Variations of the coronary heart disease (CHD) risk according to these cardiovascular measures were also explored.

Results:

All polymorphisms of the 193 patients were in Hardy-Weinberg equilibrium. Genetic determinants of cardiovascular effects affected the individual variability of the response to ACE inhibitors and statins. ACE inhibitors, but not statins, reduced blood pressure for all patients. ACE inhibitors protected carriers of alleles that supposedly decrease serum ACE levels (rs1800764-T, rs4291-A, Alu II) regarding creatinine clearance variations (P<0.005), but carriers of Alu DD (P<0.02), rs1800764-C (P<0.05), or rs4291-AT (P<0.04) showed better blood pressure lowering effects. The presence of rs2695121-T (P=0.007) or rs5930-A (P=0.039) was associated with systolic blood pressure lowering, whereas rs5930-AA was protective against decrease in creatinine clearance (P=0.019). Statins lowered creatinine clearance for carriers of rs2695121-CT (P=0.026).

Interpretation & conclusions:

Pharmacological response of blood pressure and creatinine clearance to ACE inhibitors and statins may be genetically mediated.

Exploring the complexity: the interplay between the angiotensin-converting enzyme insertion/deletion polymorphism and the sympathetic response to hemodialysis

Patients on hemodialysis (HD) are at increased risk for arrhythmias and sudden cardiac death. Autonomic nervous system (ANS) dysfunction seems to participate in the arrhythmogenic process. Genetic factors have an impact on ANS modulation, but the specific role of the insertion/deletion (I/D) polymorphism in the gene for angiotensin-converting enzyme (ACE) has not been investigated. Since the D allele increases gene expression, it is a candidate polymorphism to interact with the ANS. The aim of the present study was to compare the behavior of heart rate variability (HRV) during HD, as a surrogate for ANS response to stressors, between the ACE genotypes. In a sample of patients with chronic kidney disease I/D ACE genotypes were assessed with PCR and HRV was measured before, in the second hour, and after a HD session. HRV parameters in the time and frequency domains were analyzed by repeated-measures mixed models according to the time of measurement and ACE polymorphism. HRV parameters in the frequency domain presented significantly different variations during the HD session between patients with or without the D allele. Only patients with the II genotype presented an increase in low-frequency normalized units and in the low frequency-to-high frequency ratio throughout HD. Patients with the II genotype seemed to have a more physiological response to the volemic and electrolytic changes that occur during HD, with greater sympathetic activation than patients with ID and DD genotypes. NEW & NOTEWORTHY Adding to the effort to understand the complexity of cardiovascular system regulation, we have found that the autonomic nervous system response to the acute volume removal during hemodialysis may be different between angiotensin-converting enzyme insertion/deletion polymorphisms. To our knowledge, this is the first time that this specific interaction was analyzed during a volume removal intervention.

The angiotensin-I-converting enzyme insertion/deletion in polymorphic element codes for an AluYa5 RNA that downregulates gene expression

Angiotensin-I-converting enzyme (ACE) is involved in the synthesis and degradation of important bioactive peptides. The ACE gene has a 287-bp insertion/deletion polymorphism that controls ACE expression through a mechanism that remains elusive. In this study, we found that the 287-bp polymorphic element of the ACE gene, a member of the AluYa5 sub-family of Alu elements, codes for an RNA molecule that controls the levels of ACE mRNA. Transient transfection of a plasmid containing a CMV promoter upstream of the ACE polymorphic element resulted in significant expression of an AluYa5 RNA and reduced ACE mRNA expression as well as ACE enzymatic activity in AD 293 cells. The AluYa5 element also independently reduced the expression of other genes, regardless of whether these genes harbored Alu elements within their genomic context. Interestingly, the CMV promoter was not required for the expression of the AluYa5 element in AD 293 cells. The 287-bp sequence was sufficient to produce AluYa5 RNA and led to a significant reduction in ACE gene expression. Moreover, the removal of an 11-bp fragment of the 3' end of the ACE polymorphic sequence, which is specific to this particular AluYa5 element, did not prevent this element from being expressed but did affect its ability to target ACE expression. Thus, the expression of the AluYa5 polymorphic element within the ACE gene could explain why patients carrying the ACE insertion polymorphism have reduced risk of developing several chronic diseases.

Aerobic exercise training differentially affects ACE C- and N-domain activities in humans: Interactions with ACE I/D polymorphism and association with vascular reactivity

Introduction:

Previous studies have linked angiotensin-converting enzyme (ACE) insertion (I)/deletion (D) polymorphism (II, ID and DD) to physical performance. Moreover, ACE has two catalytic domains: NH2 (N) and COOH (C) with distinct functions, and their activity has been found to be modulated by ACE polymorphism. The aim of the present study is to investigate the effects of the interaction between aerobic exercise training (AET) and ACE I/D polymorphism on ACE N- and C-domain activities and vascular reactivity in humans.

Materials and methods:

A total of 315 pre-selected healthy males were genotyped for II, ID and DD genotypes. Fifty completed the full AET (II, n = 12; ID, n = 25; and DD, n = 13), performed in three 90-minute sessions weekly, in the four-month exercise protocol. Pre- and post-training resting heart rate (HR), peak O₂ consumption (VO₂ peak), mean blood pressure (MBP), forearm vascular conduction (FVC), total circulating ACE and C- and N-domain activities were assessed. One-way ANOVA and two-way repeated-measures ANOVA were used.

Results:

In pre-training, all variables were similar among the three genotypes. In post-training, a similar increase in FVC (35%) was observed in the three genotypes. AET increased VO₂ peak similarly in II, ID and DD (49±2 vs. 57±1; 48±1 vs. 56±3; and 48±5 vs. 58±2 ml/kg/min, respectively). Moreover, there were no changes in HR and MBP. The DD genotype was also associated with greater ACE and C-domain activities at pre- and post-training when compared to II. AET decreased similarly the total ACE and C-domain activities in all genotypes, while increasing the N-domain activity in the II and DD genotypes. However, interestingly, the measurements of N-domain activity after training indicate a greater activity than the other genotypes. These results suggest that the vasodilation in response to AET may be associated with the decrease in total ACE and C-domain activities, regardless of genotype, and that the increase in N-domain activity is dependent on the DD genotype.

Conclusions:

AET differentially affects the ACE C- and N-domain activities, and the N-domain activity is dependent on ACE polymorphism.

Different metabolic responses induced by long-term interdisciplinary therapy in obese adolescents related to ACE I/D polymorphism

Introduction:

The main purpose of the present study was to investigate whether I/D polymorphism of the ACE gene might affect metabolic changes related to the metabolic syndrome through a long-term interdisciplinary therapy in obese adolescents.

Methods:

In total, 125 obese adolescents who entered the interdisciplinary obesity programme were assigned to the following two subgroups: metabolic syndrome or non-metabolic syndrome. They were evaluated at baseline and after 1 year. Genomic DNA was extracted from circulating leukocytes.

Results:

Subjects with the II genotype in the non-metabolic syndrome group were only to increase their fat-free mass after therapy. Regarding lipid profile, subjects with ID and DD genotypes from both groups reduced their low-density lipoprotein cholesterol levels significantly. The metabolic parameters from the ID and DD genotypes of the non-metabolic syndrome group showed a significantly improved insulin response.

Conclusion:

In the present study, we showed that the ACE polymorphism was able to influence the fat-free mass in the I-carry allele in the non-metabolic syndrome group positively. In addition, the I-carry allele was able to improve the insulin resistance of the metabolic syndrome group significantly. These results suggest that the ACE I/D genotypes can influence, in different ways, the specific parameters of metabolism among obese adolescents submitted for long-term interdisciplinary therapy.

The ACTN3 R577X polymorphism affects the lipid profile and the prognosis of nutritional intervention in HIV-positive patients

The hypothesis of the present study is that the polymorphisms in the APOC3, CEPT, ACE, and ACTN3 genes can affect the outcome of nutritional intervention and the plasma lipid profile of HIV+ patients. To test the hypothesis, genetic material was collected from buccal cells, and serum was collected for biochemical analysis. Sixty-five patients were analyzed. The incorporation of protease inhibitor (PI) was more frequent in women (77% vs 33% in men). Nutritional intervention improved anthropometric parameters independent of the genotype. Patients with the RR genotype for the ACTN3 R577X polymorphism had lower glycemia (RR = 95.4 ± 6.5 mg/dL, RX = 102.6 ± 10.6 mg/dL, XX = 110.1 ± 16.3 mg/dL; P = .03) and a greater reduction in low-density lipoproteins (LDL) after intervention (LDL: RR = -23.7 ± 15.8 mg/dL, RX = 1.32 ± 5.13 mg/dL, XX = 30.21 ± 24.4 mg/dL; P = .01). Patients using PI had a negative response to dietary intervention regarding the levels of high-density lipoprotein (-2.4 ± 1.70 with PI, 2.56 ± 1.60 mg/dL without PI; P = .02), very low density lipoprotein (0.84 ± 2.73 with IP, -5.46 ± 3.37 mg/dL without PI; P = .03), and triglycerides (1.79 ± 13.22 with PI, -34.00 ± 17.67 mg/dL without PI; P = .052). This response was also independent of the genotype (P > 0.05) and suggested the need for oral lipid-lowering drugs in all HIV+ patients using PI. Our results indicate that the ACTN3 R577X polymorphism is a good predictor of both the lipid profile and the prognosis of nutritional intervention in reducing LDL in HIV+ patients.

Angiotensin-converting enzyme gene insertion-deletion polymorphism is a risk marker for Alzheimer's disease in a Chinese population: a meta-analysis of case-control studies

It has long been known that the polymorphisms of angiotensin-converting enzyme gene (ACE) are associated to increase risk of Alzheimer's disease (AD) in Chinese population. However, consistent results were not obtained among studies. This study is aimed to clarify the association between ACE insertion (I)/deletion (D) polymorphism (rs1799752) and AD. Literatures were searched from PubMed, Embase, Cochrane Library, CNKI, Wanfang and VIP databases without language restrictions. Eleven separate studies were suitable for the inclusion criterion. The selected studies contained 2,763 Chinese participants, including 1,383 in AD group and 1,380 controls. Pooled odds ratios (ORs) were calculated to assess the association between ACE I/D polymorphism and AD. Our case-control data indicated that ACE insertion is a risk allele in all genetic models: additive model (I vs. D: OR = 1.32, 95 % CI 1.07-1.62, P = 0.008), dominant model (II + ID vs. DD: OR = 1.61, 95 % CI 1.08-2.41, P = 0.02) and recessive model (II vs. ID + DD: OR = 1.39, 95 % CI 1.07-1.81, P = 0.01). Heterogeneity between studies was significant (P < 0.10) but not in stratification defined by the selection of controls (P > 0.10). After stratification according to the selection of controls, the carrier of ACE I allele remained a high risk for AD in population-based samples subgroup (I vs. D: P = 0.008, OR = 1.32, 95 % CI 1.07-1.61, P(heterogeneity) = 0.47, I (2) = 0 %). Our study provided solid evidence suggesting that ACE gene I/D polymorphism is a genetic risk factor for AD in Chinese population.

Genomics in rugby union: A review and future prospects

This article introduces some aspects of sports genomics in a rugby union context, considers the rugby-specific genetic data in the published literature and outlines the next research steps required if the potential applications of genetic technology in rugby union, also identified here, are to become possible. A substantial proportion of the inter-individual variation for many traits related to rugby performance, including strength, short-term muscle power, VO2 max, injury susceptibility and the likelihood of being an elite athlete is inherited and can be investigated using molecular genetic techniques. In sports genomics, significant efforts have been made in recent years to develop large DNA biobanks of elite athletes for detailed exploration of the heritable bases of those traits. However, little effort has been devoted to the study of rugby athletes, and most of the little research that has focused on rugby was conducted with small cohorts of non-elite players. With steadily growing knowledge of the molecular mechanisms underpinning complex performance traits and the aetiology of injury, investigating sports genomics in the context of rugby is now a viable proposition and a worthwhile endeavour. The RugbyGene project we describe briefly in this article is a multi-institutional research collaboration in rugby union that will perform molecular genetic analyses of varying complexity. Genetic tests could become useful tools for rugby practitioners in the future and provide complementary and additional information to that provided by the non-genetic tests currently used.

Polymorphism of the ace gene and the α-actinin-3 gene in adolescent idiopathic scoliosis

OBJECTIVE

: The I/D polymorphism of angiotensin-converting enzyme (ACE) and R577X of the α-actinin-3 (ACTN3) is related to changes in skeletal muscle function. The aim of this study was to evaluate the distribution of these polymorphisms in a family with multiple members with adolescent idiopathic scoliosis (AIS).

METHODS

: Evaluated 25 subjects from a family with multiple members with AIS, by collecting 10mL of blood for DNA isolation. The genotyping of the I/D polymorphism of the ACE gene and the R577X of the ACTN3 gene was performed using two specific primers to classify individuals as homozygous or heterozygous.

RESULTS

: Regarding the ACE polymorphism it was found that 19 (76%) subjects were DD and 6 (24%) ID. The prevalence of the D allele was 88% and the I allele was 12%. Regarding the ACTN3 polymorphism there were 6 subjects RR (24%), 11 RX (44%) and 8 XX (32%). The prevalence of the R allele was 23 (46%) and the X allele was 27 (54%).

CONCLUSION

: There was a difference between the distribution of the polymorphism of ACE and ACTN3 in the family studied. When assessing the ACE polymorphism a higher prevalence of the D allele was observed as compared with the I allele. Level of Evidence III, Cross-sectional, Clinical Trial.

The angiotensin converting enzyme insertion/deletion polymorphism alters the response of muscle energy supply lines to exercise

The presence of a silencing sequence (the I-allele) in the gene for the upstream regulator of blood flow, angiotensin I-converting enzyme (ACE), is associated with superior endurance performance and its trainability. We tested in a retrospective study with 36 Caucasian men of Swiss descent whether carriers of the ACE I-allele demonstrate a modified adaptive response of energy supply lines in knee extensor muscle, and aerobic fitness, to endurance training based on 6 weeks of supervised bicycle exercise or 6 months of self-regulated running (p value <Bonferroni-corrected 5 %). Body weight related maximal oxygen uptake and capillary density in vastus lateralis muscle before training were 20 and 23 % lower, respectively, in carriers of the I-allele. Bicycle (n = 16) but not running type endurance training (n = 19) increased the volume content of subsarcolemmal mitochondria (2.5-fold) and intramyocellular lipid (2.1-fold). This was specifically amplified in I-allele carriers after 6 weeks of bicycle exercise. The enhanced adjustment in myocellular organelles of aerobic metabolism with bicycle training corresponded to ACE I-allele dependent upregulation of 23 muscle transcripts during recovery from the bicycle stimulus and with training. The majority of affected transcripts were associated with glucose (i.e. ALDOC, Glut2, LDHC) and lipid metabolism (i.e. ACADL, CPTI, CPTII, LIPE, LPL, FATP, CD36/FAT); all demonstrating an enhanced magnitude of change in carriers of the ACE I-allele. Our observations suggest that local improvements in mitochondrial metabolism, through a novel expression pathway, contribute to the varying trainability in endurance performance between subjects with genetically modified expression of the regulator of vascular tone, ACE.

Functional regulation of Alu element of human angiotensin-converting enzyme gene in neuron cells

The angiotensin-converting enzyme (ACE) insertion/deletion (I/D) genotype and its protein activity have been widely implicated to be associated with Alzheimer's disease (AD). However, whether the insertion sequence, Alu element, in intron 16 of the human ACE gene plays a functional role remains uncertain. To investigate the influence of the I/D polymorphism on ACE promoter, we recombined the I and D form fragments with the human ACE promoter sequence before the reporter gene in pSEAP-Basic2 vector. The effect of the Alu element on regulating the transcriptional activity of ACE promoter was examined using transient transfection in SH-SY5Y cells. We found that the I form fragment upregulated the transcriptional activity of ACE promoter by approximately 70% but that the D form fragment did not. Our study first reveals that Alu sequence in human ACE gene possesses a regulatory function on the ACE promoter activity in neuron. This novel finding bridges the gap between the association of ACE I/D genotype with AD, and suggests that Alu sequence is not merely a "junk" DNA in human ACE gene.

The kallikrein-kinin system and oxidative stress

PURPOSE OF REVIEW

The kallikrein-kinin system (KKS) constitutes a complex multienzyme cascade that produces several bioactive kinin peptides and their derivatives including bradykinin. In addition to the classical notion of the KKS as a potent vasodilator and a mediator of inflammatory responses, recent studies suggest a link between the KKS and oxidative stress. A number of established mouse models with altered levels of KKS components opened the way to evaluate precise functions of the KKS. Here we review recent findings on the role of the KKS in cardiovascular diseases and chronic kidney diseases, and discuss potential benefits of KKS activation in these diseases.

RECENT FINDINGS

Deletion of both B1R and B2R in a diabetic mouse model exacerbates its renal phenotypes, suggesting that the KKS exerts protective effects on diabetic nephropathy by suppressing oxidative stress, presumably via nitric oxide and prostaglandins.

SUMMARY

Accumulating evidence has highlighted the importance of the KKS as a protective system against oxidative stress and organ damage in the heart and kidney. The activation of the KKS by angiotensin I-converting enzyme inhibitors and vasopeptidase inhibitors is likely to be beneficial in senescence-associated cardiovascular diseases and chronic kidney diseases.

Carbamazepine inhibits angiotensin I-converting enzyme, linking it to the pathogenesis of temporal lobe epilepsy

We find that a common mutation that increases angiotensin I-converting enzyme activity occurs with higher frequency in male patients suffering from refractory temporal lobe epilepsy. However, in their brains, the activity of the enzyme is downregulated. As an explanation, we surprisingly find that carbamazepine, commonly used to treat epilepsy, is an inhibitor of the enzyme, thus providing a direct link between epilepsy and the renin-angiotensin and kallikrein-kinin systems.

The kallikrein-kinin system in diabetic nephropathy

Diabetic nephropathy is the major cause of end-stage renal disease worldwide. Although the renin-angiotensin system has been implicated in the pathogenesis of diabetic nephropathy, angiotensin I-converting enzyme inhibitors have a beneficial effect on diabetic nephropathy independently of their effects on blood pressure and plasma angiotensin II levels. This suggests that the kallikrein-kinin system (KKS) is also involved in the disease. To study the role of the KKS in diabetic nephropathy, mice lacking either the bradykinin B1 receptor (B1R) or the bradykinin B2 receptor (B2R) have been commonly used. However, because absence of either receptor causes enhanced expression of the other, it is difficult to determine the precise functions of each receptor. This difficulty has recently been overcome by comparing mice lacking both receptors with mice lacking each receptor. Deletion of both B1R and B2R reduces nitric oxide (NO) production and aggravates renal diabetic phenotypes, relevant to either lack of B1R or B2R, demonstrating that both B1R and B2R exert protective effects on diabetic nephropathy presumably via NO. Here, we review previous epidemiological and experimental studies, and discuss novel insights regarding the therapeutic implications of the importance of the KKS in averting diabetic nephropathy.