Ang-(1-7) protects skeletal muscle function in aged mice

BIO101 stimulates myoblast differentiation and improves muscle function in adult and old mice

BACKGROUND

Muscle aging is associated with a consistent decrease in the ability of muscle tissue to regenerate following intrinsic muscle degradation, injury or overuse. Age-related imbalance of protein synthesis and degradation, mainly regulated by AKT/mTOR pathway, leads to progressive loss of muscle mass. Maintenance of anabolic and regenerative capacities of skeletal muscles may be regarded as a therapeutic option for sarcopenia and other muscle wasting diseases. Our previous studies have demonstrated that BIO101, a pharmaceutical grade 20-hydroxyecdysone, increases protein synthesis through the activation of MAS receptor involved in the protective arm of renin-angiotensin-aldosterone system. The purpose of the present study was to assess the anabolic and pro-differentiating properties of BIO101 on C2C12 muscle cells in vitro and to investigate its effects on adult and old mice models in vivo.

METHODS

The effects of BIO101 on C2C12 differentiation were assessed using myogenic transcription factors and protein expression of major kinases of AKT/mTOR pathway by Western blot. The in vivo effects of BIO101 have been investigated in BIO101 orally-treated (50 mg/kg/day) adult mice (3 months) for 28 days. To demonstrate potential beneficial effect of BIO101 treatment in a sarcopenic mouse model, we use orally treated 22-month-old C57Bl6/J mice, for 14 weeks with vehicle or BIO101. Mice body and muscle weight were recorded. Physical performances were assessed using running capacity and muscle contractility tests.

RESULTS

Anabolic properties of BIO101 were confirmed by the rapid activation of AKT/mTOR, leading to an increase of C2C12 myotubes diameters (+26%, P < 0.001). Pro-differentiating effects of BIO101 on C2C12 myoblasts were revealed by increased expression of muscle-specific differentiation transcription factors (MyoD, myogenin), resulting in increased fusion index and number of nuclei per myotube (+39% and +53%, respectively, at day 6). These effects of BIO101 were like those of angiotensin (1-7) and were abolished with the use of A779, a MAS receptor specific antagonist. Chronic BIO101 oral treatment induced AKT/mTOR activation and anabolic effects accompanied with improved physical performances in adult and old animals (maximal running distance and maximal running velocity).

CONCLUSIONS

Our data suggest beneficial anabolic and pro-differentiating effects of BIO101 rendering BIO101 a potent drug candidate for treating sarcopenia and possibly other muscle wasting disorders.

Muscle quality is negatively related to hypertension prevalence in adults: Results from NHANES 2011-2014

Resistance training could counter hypertension and improve muscle quality (MQ), but current evidence about the correlation between MQ and hypertension is limited. The authors aimed to explore this correlation using the data of participants aged 20-59 from NHANES 2011-2014 via a cross-sectional study. The MQ was quantified as handgrip strength (kg)/lean soft tissue mass (kg) of the dominant arm. Weighted multivariate logistic regression models were mainly utilized to investigate the MQ-hypertension association; linear trend tests and subgroup analysis were also conducted. Moreover, the authors employed weighted multivariate linear regression models to uncover the association between blood pressure (BP) and MQ. Four thousand four hundred and sixty-nine individuals were enrolled, and 1167 were hypertensive. Hypertensive participants had a lower MQ than normotensive participants. In the totally adjusted model, each unit elevation in MQ was related to a 7% reduction in hypertension prevalence (p =.002). There was a decreasing trend in hypertension prevalence and in systolic BP as the MQ increased from the bottom to the top quartile across all three models (p for trend ≤.01), with a 28% difference (OR: 0.72, 95% CI: 0.54, 0.95) in hypertension prevalence and a 1.88 mm Hg (95% CI: -3.56, -0.20) difference in SBP between the top and bottom quartiles in the fully adjusted model. Subgroup analysis further confirmed the MQ-hypertension inverse association. In conclusions, the MQ was negatively associated with hypertension prevalence and systolic BP, which suggests the MQ may be a protective factor for hypertension and need to be improved.

Novel Potential Targets for Function-Promoting Therapies: Orphan Nuclear Receptors, Anti-inflammatory Drugs, Troponin Activators, Mas Receptor Agonists, and Urolithin A

In recent years, several new classes of therapies have been investigated with their potential for restoring or improving physical functioning in older adults. These have included Mas receptor agonists, regulators of mitophagy, skeletal muscle troponin activators, anti-inflammatory compounds, and targets of orphan nuclear receptors. The present article summarizes recent developments of the function-promoting effects of these exciting new compounds and shares relevant preclinical and clinical data related to their safety and efficacy. The development of novel compounds in this area is expanding and likely will need the advent of a new treatment paradigm for age-associated mobility loss and disability.