SOD2gene polymorphism and muscle damage markers in elite athletes

Abstract

Exercise-induced oxidative stress is a state that primarily occurs in athletes involved in high-intensity sports when pro-oxidants overwhelm the antioxidant defense system to oxidize proteins, lipids, and nucleic acids. During exercise, oxidative stress is linked to muscle metabolism and muscle damage, because exercise increases free radical production. The T allele of the Ala16Val (rs4880 C/T) polymorphism in the mitochondrial superoxide dismutase 2 (SOD2) gene has been reported to reduce SOD2 efficiency against oxidative stress. In the present study we tested the hypothesis that the SOD2 TT genotype would be underrepresented in elite athletes involved in high-intensity sports and associated with increased values of muscle and liver damage biomarkers. The study involved 2664 Caucasian (2262 Russian and 402 Polish) athletes. SOD2 genotype and allele frequencies were compared to 917 controls. Muscle and liver damage markers [creatine kinase (CK), creatinine, alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP)] were examined in serum from 1444 Russian athletes. The frequency of the SOD2 TT genotype (18.6%) was significantly lower in power/strength athletes (n = 524) compared to controls (25.0%, p = 0.0076) or athletes involved in low-intensity sports (n = 180; 33.9%, p < 0.0001). Furthermore, the SOD2 T allele was significantly associated with increased activity of CK (females: p = 0.0144) and creatinine level (females: p = 0.0276; males: p = 0.0135) in athletes. Our data show that the SOD2 TT genotype might be unfavorable for high-intensity athletic events.

Genetic variation and exercise-induced muscle damage: implications for athletic performance, injury and ageing

“…Akimoto et al ( 2010 ) demonstrated that trained runners of TT genotype had an increased plasma CK concentration after racing 4–21 km. This is in line with Ahmetov et al ( 2014 ), who revealed that TT carriers of the mitochondrial superoxide dismutase gene were under-represented in power and strength athletes compared to controls and athletes of low-intensity sports, such as curling players and shooters. Interestingly, in the study of Ben-Zaken et al ( 2013 ), the frequency of the C-allele was significantly higher in both endurance and power athletes in comparison to the control group.…”

“…On closer inspection, both studies recruited different types of participants. In the study of Ahmetov et al ( 2014 ) participants covered a wide range of different sports, whereas in Ben-Zaken et al ( 2013 ), only track and field related athletes participated: 100 and 200 m sprinters and long jumpers (power athletes); 5000 m and marathon runners (endurance athletes). These track and field athletes perform sport-specific movements that is accompanied by stress to the musculoskeletal system through repeated eccentric muscle contractions performed over long periods of time, which leads to muscle damage.…”

Greater muscle damage in athletes with ACTN3 R577X (RS1815739) gene polymorphism after an ultra-endurance race: a pilot study

“…These contradictory results may be explained as a result of the heterogeneity of the population studies and the training status, since neither study investigated well-trained individuals [18, 32]. Other gene polymorphisms have also been associated with muscle damage [33–35], and the interaction effect between two or more gene polymorphisms on muscle damage susceptibility can better clarify this response.…”

Current Progress in Sports Genomics

“…In the first study involving 74 Israeli power athletes (100-200 m sprinters and long jumpers), Ben-Zaken et al [243] found that the frequency of the SOD2 Ala16 allele was significantly higher in athletes (45% vs. 29%; P < 0.001) compared with controls. In a subsequent study of Russian and Polish athletes [244], the frequency of the SOD2 Val/Val genotype (18.6%) was shown to be significantly lower in power/ strength athletes (n ¼ 524) compared to controls (25.0%; P ¼ 0.0076) or athletes involved in low-intensity sports (n ¼ 180; 33.9%; P < 0.0001). Furthermore, the SOD2 16Val allele was significantly associated with increased activity of creatine kinase (females: P ¼ 0.0144) and creatinine level (females: P ¼ 0.0276; males: P ¼ 0.0135) in athletes.…”