Mitochondria are dynamic organelles forming a tubular network that is continuously fusing and dividing to control their morphology and functions. Recent literature has shed new light on a potential link between the dynamic behavior of mitochondria and muscle development. In this study, we investigate the role of mitochondrial fission factor dynamin-related protein 1 (Drp1) in myogenic differentiation. We found that differentiation of C2C12 myoblasts induced by serum starvation was accompanied by a gradual increase in Drp1 protein expression (to ∼350% up to 3 days) and a fast reduction of Drp1 phosphorylation at Ser-637 (to ∼30%) resulting in translocation of Drp1 protein from the cytosol to mitochondria. During differentiation, treatment of myoblasts with mitochondrial division inhibitor ( mdivi-1), a specific inhibitor of Drp1 GTPase activity, caused extensive formation of elongated mitochondria, which coincided with increased apoptosis evidenced by both enhanced caspase-3 activity and increased number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells. Furthermore, the mdivi-1-treated myotubes ( day 3 in differentiation media) showed a reduction in mitochondrial DNA content, mitochondrial mass, and membrane potential in a dose-dependent manner indicating defects in mitochondrial biogenesis during myogenic differentiation. Most interestingly, mdivi-1 treatment significantly suppressed myotube formation in both C2C12 cells and primary myoblasts. Likewise, stable overexpression of a dominant negative mutant Drp1 (K38A) dramatically reduced myogenic differentiation. These data suggest that Drp-1-dependent mitochondrial division is a necessary step for successful myogenic differentiation, and perturbation of mitochondrial dynamics hinders normal mitochondrial adaptations during muscle development. Therefore, in the present study, we report a novel physiological role of mitochondrial dynamics in myogenic differentiation.

Dietary supplementation of strawberry attenuates indices of vascular inflammation and dysfunction in diabetic db/db mice. The effect of strawberry on vasculature is endothelial-dependent and possibly mediated through their circulating metabolites. Strawberry might complement conventional therapies to improve vascular complications in diabetics.

Objective: Aging is associated with progressive decreases in arterial health as well as muscular strength and cardiorespiratory capacity. It is crucial to prevent or reduce the negative effects of aging on vasculature, muscular, and cardiorespiratory function by implementing appropriate lifestyle interventions, such as exercise training. We examined the effects of a swimming (SWM) regimen on arterial stiffness (pulse wave velocity [PWV]), blood pressure (BP), wave reflection (augmentation index [AIx]), muscle strength, and aerobic capacity in sedentary, postmenopausal women with stage 2 hypertension. Methods: One hundred participants (∼74 years of age) were recruited from multiple general practice centers. Using a parallel experimental design, participants were randomly assigned to either SWM (n = 52) or nonexercising control group (n = 48) for 20 weeks. Participants in the SWM group trained 3 to 4 days/week. Participants’ carotid to radial PWV, BP, AIx, muscular strength, and cardiorespiratory capacity were measured at baseline and after 20 weeks of their assigned intervention. Results: There was a significant group × time interaction (P < 0.05) for carotid to radial PWV (Δ−1.2 m/s), AIx (Δ−4%), and systolic (Δ−9 mm Hg) and diastolic BP (Δ − 9 mm Hg), which significantly decreased (P < 0.05); and strength (Δ3 kg) and cardiorespiratory capacity (Δ4 mL/kg/min), which significantly increased (P < 0.05) following SWM compared to no changes in control. Conclusions: SWM led to reductions in arterial stiffness, wave reflection, and BP while increasing strength and aerobic capacity in postmenopausal women with stage 2 hypertension. SWM may be an effective intervention in the prevention and treatment of age-related vascular complications and declines in muscle strength and cardiorespiratory capacity.

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BackgroundLow-fluence 1,064 nm Q-switched Nd:YAG laser has been widely used for the treatment of melasma. Although new Q-switched Nd:YAG lasers with photoacoustic twin pulse (PTP) mode have been recently developed for high-efficiency, there is limited information available for the new technique.ObjectiveThis study was designed to investigate the efficacy and adverse effects after few sessions of repeated low fluence 1,064 nm Q-switched Nd:YAG laser treatment with PTP mode in Asian women with melasma.MethodsTwenty-two Korean women were treated with a total of five sessions of low-fluence PTP mode Nd:YAG laser treatment (Pastelle®) at 2 weeks interval. Responses to treatments were evaluated by using Melasma Area and Severity Index (MASI) scoring, colorimeter measurement, and the investigators' and patients' overall assessments. Adverse events were recorded at each visit.ResultsInvestigators' and patients' overall assessment showed that 'significantly improved' was assessed by 13 (59.1%) and 19 of 22 patients (86.4%), respectively. MASI scores were significantly reduced by 20.4%. The lightness, measured by using a colorimeter, was significantly increased by 1.3 point. Notable adverse events were not observed.ConclusionAfter 5 sessions of laser therapy alone, about 60% of the subjects showed significant improvement. Few sessions of repeated laser toning treatment using the PTP mode is a safe and effective way to treat facial melasma.