Satellite Cells Exhibit Decreased Numbers and Impaired Functions on Single Myofibers Isolated from Vitamin B6-Deficient Mice

Relationship of Low Vitamin B6 Status with Sarcopenia, Frailty, and Mortality: A Narrative Review

Marginal vitamin B6 (B6) deficiency is a widespread global concern. Inadequate B6 levels have been linked to an increased risk of age-related chronic diseases such as cardiovascular diseases and cancers. In recent years, the growing concern over sarcopenia (the age-related loss of muscle mass and strength) and frailty (a decline in physiological resilience and increased vulnerability associated with aging) is particularly relevant due to the emergence of super-aged societies in developed countries. Notably, among the thirty-one studies included in this review, twenty-five showed a significant association of B6 status with sarcopenia, frailty, and all-cause mortality in adults (p < 0.05), while six showed no association. Emerging studies have suggested novel mechanisms underlying this association. These mechanisms involve P2X7 receptor-mediated NLRP3 inflammasome signaling, AMPK signaling, PD-L1 signaling, and satellite cell-mediated myogenesis. Furthermore, the modulation of PLP-dependent enzymes due to B6 deficiency is associated with impaired metabolic processes, affecting energy utilization, imidazole peptide production, and hydrogen sulfide production, as well as the kynurenine pathway, all of which play vital roles in skeletal muscle health and pathophysiology. This narrative review provides an up-to-date assessment of our current understanding of the potential role of nutritional B6 status in combating sarcopenia, frailty, and mortality.

Comparison of Muscle, Bone and Fat Indices between Stages of Sarcopenia in Postmenopausal Malaysian Women

Background

The cumulative health impact of sarcopenia when it overlaps with obesity and osteoporosis is poorly understood. This cross-sectional study compared the muscle, bone and fat indices between stages of sarcopenia and determined the association of sarcopenia stages with adiposity and bone density in Malaysian postmenopausal women.

Methods

One hundred and thirty-six postmenopausal Malaysian women from Semenyih and Kuala Lumpur, Malaysia participated in the study. Muscle mass and body fat percentages (BFP) were assessed using a bioelectrical impedance analyser. Bone density was assessed using quantitative calcaneal ultrasonography. Handgrip strength (HGS) was assessed using a handgrip dynamometer. Gait speed was assessed using the 6-m walk test. The sarcopenia stage was classified into pre-sarcopenia, sarcopenia and severe sarcopenia.

Results

The overall prevalence of participants with various stages of 'sarcopenia' was 29.4%. The rates of low bone density were 13.7%, 12.5%, 17.4% and 85.7% in the non-sarcopenic, pre-sarcopenic, sarcopenic and severe sarcopenic groups, respectively (P < 0.000). Age, adiposity, muscle mass, gait speed and bone density differed significantly between the reference (non-sarcopenic) and 'severe sarcopenic' groups. The 'sarcopenic' and 'severe sarcopenic' groups had common impairments whereby no significant differences were found in HGS and gait speed between them.

Conclusion

The results showed significant correlations between sarcopenia stages and age, body weight, adiposity and bone density. Individuals with 'sarcopenia' had the same level of HGS and gait speed as those with severe forms of the disorder, implying that individuals with sarcopenia and severe sarcopenia were at the same level in terms of strength and endurance.

Nutrition and Regulation of Muscle Protein Synthesis

Skeletal muscles are an indispensable actor for daily activities, playing an essential role in locomotion through both the control of posture and position and by joint stabilization [...].

Effects of energy drinks on myogenic differentiation of murine C2C12 myoblasts

Energy drinks, often advertised as dietary supplements that enhance physical and mental performance, have gained increasing popularity among adolescents and athletes. Several studies on individual ingredients such as caffeine or taurine have reported either adverse or favorable influences on myogenic differentiation, a key process in muscle regeneration to repair microtears after an intense workout session. However, the impact of different energy drinks with various formulas on muscle differentiation has never been reported. This study aims to examine the in vitro effects of various energy drink brands on myogenic differentiation. Murine C2C12 myoblast cells were induced to differentiate into myotubes in the presence of one of eight energy drinks at varying dilutions. A dose-dependent inhibition of myotube formation was observed for all energy drinks, supported by reduced percentage of MHC-positive nuclei and fusion index. Moreover, expression of myogenic regulatory factor MyoG and differentiation marker MCK were also decreased. Furthermore, given the variation in formulas of different energy drinks, there were remarkable differences in the differentiation and fusion of myotubes between energy drinks. This is the first study to investigate the impact of various energy drinks on myogenic differentiation and our results suggest an inhibitory effect of energy drinks in muscle regeneration.