The Effects of Angiotensin I-Converting Enzyme (ACE) I/D and Alpha-Actinin-3 (ACTN3) R/X Gene Polymorphisms on Human Physical Performance and Health within Malaysian Population

摘要

A disparity population data set in the current literature with limited reportsudamong Asian samples, coupled with the inconsistent findings among different ethnicudgroups, and lack of information for the involvement of angiotensin I-convertingudenzyme (ACE) I/D and alpha-actinin-3 (ACTN3) R/X gene polymorphisms in trainingudadaptation have limited the ability of researchers to draw meaningful conclusionsudpertaining to the effects of these polymorphisms on human physical performance andudhealth. Therefore, this doctoral research implemented three series of studies toudexamine the effects of ACE I/D and ACTN3 R/X gene polymorphisms on humanudphysical performance and health within the Malaysian population. In the first study,udDNA samples were retrieved via buccal cell from 180 Asians from Malaysia (70udmales, 110 females) aged 20.4 ± 1.6 years, and 180 Caucasians from Australia (62udmales, 118 females) aged 23.3 ± 3.6 years. In the second study, DNA samples wereudretrieved from 180 well-trained Malaysian athletes (148 males, 32 females) agedud20.5 ± 1.9 years, 180 Malaysian sedentary controls, and 33 intermittent Australianudathletes (all males) aged 20.7 ± 4.0 years. Endurance and muscular performances ofudMalaysian athletes were evaluated with 20 meters Yo-Yo intermittent recovery levelud2 and maximal voluntary contraction tests, respectively. In the third study, thirtyudnormotensive, untrained males (ACE genotype: II = 10, ID = 10, and DD = 10),udundergone isometric handgrip training (four sets of 2 minutes isometric contractionsudat 30% of maximal voluntary contraction, with 1 minute resting interval) 3 days perudweek for 8 weeks. The result from the first study indicated that the distribution ofudACE I/D gene polymorphism varied among different ethnic groups, but not toudACTN3 R/X gene polymorphism. The findings obtained from the second studyuddemonstrated that: a) The effects of these polymorphisms on endurance andudstrength/power performances did not vary by ethnicity, b) The ACE D allele andudACTN3 R allele conferred an advantage in activities that require strength/power, andudc) The ACE I allele and ACTN3 X allele did not influence endurance performance.udFinding from the final study demonstrated that ACE I/D gene polymorphism had audpositive influence in cardiovascular and muscular adaptations following isometricudhandgrip training among normotensive men. Overall, this research reaffirms theudnotion that strength/power performance is influenced by the ACE D allele andudACTN3 R allele. In addition, this research concludes that the ACE I/D geneudpolymorphism modulates response to isometric handgrip training in normotensiveudmen.