Cellular and Physiological Effects of Dietary Supplementation with β-Hydroxy-β-Methylbutyrate (HMB) and β-Alanine in Late Middle-Aged Mice

Abstract

There is growing evidence that severe decline of skeletal muscle mass and function with age may be mitigated by exercise and dietary supplementation with protein and amino acid ingredient technologies. The purposes of this study were to examine the effects of the leucine catabolite, beta-hydroxy-beta-methylbutyrate (HMB), in C2C12 myoblasts and myotubes, and to investigate the effects of dietary supplementation with HMB, the amino acid β-alanine and the combination thereof, on muscle contractility in a preclinical model of pre-sarcopenia. In C2C12 myotubes, HMB enhanced sarcoplasmic reticulum (SR) calcium release beyond vehicle control in the presence of all SR agonists tested (KCl, P<0.01; caffeine, P = 0.03; ionomycin, P = 0.03). HMB also improved C2C12 myoblast viability (25 μM HMB, P = 0.03) and increased proliferation (25 μM HMB, P = 0.04; 125 μM HMB, P<0.01). Furthermore, an ex vivo muscle contractility study was performed on EDL and soleus muscle from 19 month old, male C57BL/6nTac mice. For 8 weeks, mice were fed control AIN-93M diet, diet with HMB, diet with β-alanine, or diet with HMB and β-alanine. In β-alanine fed mice, EDL muscle showed a 7% increase in maximum absolute force compared to the control diet (202 ± 3vs. 188± 5 mN, P = 0.02). At submaximal frequency of stimulation (20 Hz), EDL from mice fed HMB plus β-alanine showed an 11% increase in absolute force (88.6 ± 2.2 vs. 79.8 ± 2.4 mN, P = 0.025) and a 13% increase in specific force (12.2 ± 0.4 vs. 10.8 ± 0.4 N/cm2, P = 0.021). Also in EDL muscle, β-alanine increased the rate of force development at all frequencies tested (P<0.025), while HMB reduced the time to reach peak contractile force (TTP), with a significant effect at 80 Hz (P = 0.0156). In soleus muscle, all experimental diets were associated with a decrease in TTP, compared to control diet. Our findings highlight beneficial effects of HMB and β-alanine supplementation on skeletal muscle function in aging mice.

Murine myoblast migration: influence of replicative ageing and nutrition

“…Cell migration was not assessed. Further, studies by Kornasio et al support the concept that HMB has beneficial effects on the proliferation and differentiation of myoblasts, through the MAPK/ERK and PI3K/Akt pathways (Kornasio et al 2009 ; Vallejo et al 2016 ). Although migration in the presence of supplements was not investigated in these reports, data from Dimchev et al suggest that the ability of myoblasts to migrate depends on the PI3K/Akt and ERK/MAPK pathways (Dimchev et al 2013 ).…”

“…Hydroxy β-methylbutyric acid (HMB), a metabolite of leucine, is increasing in popularity as an ergogenic aid for muscle recovery and regeneration. HMB studies in human myoblasts and rodents demonstrate positive effects on satellite cell proliferation, differentiation and survival, following MAPK/ERK and PI3K/Akt activation (Kornasio et al 2009 ; Vallejo et al 2016 ). Supplementation of human myoblasts with HMB (0–85 mM) stimulated cell proliferation via the MAPK/ERK pathway and induced differentiation via the PI3K/Akt pathway (Kornasio et al 2009 ).…”

“…Supplementation of human myoblasts with HMB (0–85 mM) stimulated cell proliferation via the MAPK/ERK pathway and induced differentiation via the PI3K/Akt pathway (Kornasio et al 2009 ). Further studies by Vallejo et al ( 2016 ) investigated the impact of HMB on C 2 C 12 myoblasts (25–125 µM) and on the contractile force of ageing murine soleus muscle (514 mg/kg). HMB treatment increased C 2 C 12 myoblast proliferation and myoblast viability.…”

“…HMB treatment increased C 2 C 12 myoblast proliferation and myoblast viability. In mice, HMB prolonged force generation and reduced the amount of time for peak muscle contraction following damage (Vallejo et al 2016 ). Together, these studies indicated that leucine and HMB could impact positively on muscle differentiation, survival and function.…”

Effects of beta‐hydroxy‐beta‐methylbutyrate supplementation on skeletal muscle in healthy and cirrhotic rats

“…Beta‐hydroxy‐beta‐methylbutyrate (HMB) is a leucine metabolite with protein anabolic effects, which might be effective in the treatment of muscle wasting disorders. HMB has been shown to stimulate protein synthesis through the mTOR system, increase expression of pituitary growth hormone mRNA and IGF‐1 levels, decrease proteasome enzyme activities, reduce the apoptosis of myonuclei, increase mitochondrial biogenesis and fat oxidation, and improve excitation‐contraction coupling in muscles . In humans, positive effects of HMB were observed in the elderly, and those with sepsis, chronic cardiac and pulmonary disease, hip fracture, Duchenne muscular dystrophy, and AIDS‐ and cancer‐related cachexia …”