Niacin supplementation attenuates the regression of three-dimensional capillary architecture in unloaded female rat skeletal muscle.

Inactivity can lead to muscle atrophy and capillary regression in skeletal muscle. Niacin (NA), known for inducing hypermetabolism, may help prevent this capillary regression. In this study involving adult female Sprague-Dawley rats, the animals were randomly assigned to one of four groups: control (CON), hindlimb unloading (HU), NA, and HU with NA supplementation (HU + NA). For a period of 2 weeks, the rats in the HU and HU + NA groups underwent HU, while those in the NA and HU + NA groups received NA (750 mg/kg) twice daily through oral administration. The results demonstrated that HU lowered capillary number, luminal diameter, and capillary volume, as well as decreased succinate dehydrogenase activity, slow fiber composition, and PGC-1α expression within the soleus muscle. However, NA supplementation prevented these alterations in capillary structure due to unloading by stimulating PGC-1α factors and inhibiting mitochondrial dysfunction. Therefore, NA supplementation could serve as a potential therapeutic approach for preserving the capillary network and mitochondrial metabolism of muscle fibers during periods of inactivity.

Brazilian Propolis Intake Decreases Body Fat Mass and Oxidative Stress in Community-Dwelling Elderly Females: A Randomized Placebo-Controlled Trial.

This study aimed to investigate the effects of Brazilian propolis on body fat mass and levels of adiponectin and reactive oxygen species among community-dwelling elderly females. This was a double-blind randomized placebo-controlled trial. Altogether, 78 females aged 66-84 years were randomly assigned to the propolis (PRO; n = 39) or placebo (PLA; n = 39) group. For 12 weeks, the PRO group were given three capsules containing 227 mg of propolis twice a day. Meanwhile, the PLA group were given daily placebo capsules. Of 78 participants, 53 (PLA group: n = 28, PRO group: n = 25) completed the study. Although no changes were observed in absolute or relative fat mass in the PLA group, they showed a significant decline in the PRO group. The level of serum adiponectin in the PLA group did not change, although that of the PRO group significantly increased. The level of d-ROMs in the PLA group significantly increased, whereas that of the PRO group significantly decreased. The serum SOD activity in the PLA group significantly decreased, whereas that of the PRO group tended to increase. These results suggest that propolis supplementation may decrease body fat mass and oxidative stress among community-dwelling elderly females.

Impacts of Astaxanthin Supplementation on Walking Capacity by Reducing Oxidative Stress in Nursing Home Residents.

Oxidative stress is associated with deterioration of endurance and muscle strength, which are mostly accompanied by aging. Astaxanthin supplement has excellent antioxidant activity without any pro-oxidative properties. In this study, we investigated how astaxanthin supplementation affects walking endurance and muscle strength in nursing home residents. Healthy elderly individuals (age: 67 to 94) were divided into two groups: 13 subjects received a daily dose of 24 mg of astaxanthin for 16 weeks (astaxanthin group) and 11 subjects received a placebo (placebo group). These subjects were compared using body component measurements, serum d-ROM levels, the distance of 6-min walking, blood lactate levels after the 6-min walking test, and muscle strength. After supplementation, the levels of d-ROMs and blood lactate after the 6-min walking test in the astaxanthin group significantly decreased compared with the placebo group (p < 0.05). Additionally, the walking distance was significantly higher in the astaxanthin group than in the placebo group (p < 0.05), despite a significant reduction in lactate levels after 6-MWT (p < 0.05). However, no significant intergroup differences were observed in muscle mass and strength. Astaxanthin supplement for 16 weeks is effective to increase the endurance capacity of the elderly. Astaxanthin supplement suppresses d-ROMs at rest and lactic acid production after the 6-min walk test. In contrast, astaxanthin supplement did not show significant intergroup differences in the muscle mass and strength. Therefore, the effect was most likely accompanied by an increase in endurance instead of an increase in muscle strength.

Protective effects of Enterococcus faecium strain R30 supplementation on decreased muscle endurance under disuse in rats.

NEW FINDINGS: What is the central question of this study? Does Enterococcus faecium strain R30 (R30), a new lactic acid bacterial strain for supplementation, attenuate shifts in the typology of whole muscle fibres from slow- to fast-twitch by altering the autonomic nervous system in atrophied skeletal muscles? What is the main finding and its importance? R30 supplementation may attenuate the shifts in the typology of whole muscle fibres from slow- to fast-twitch fibres by upregulating peroxisome proliferator-activated receptor-γ coactivator-1α and activating the calcineurin-nuclear factor of activated T-cells signalling pathway, thus ameliorating the decrease in muscle endurance associated with disuse. ABSTRACT: Enterococcus faecium strain R30 (R30), a new lactic acid bacterial strain for supplementation, was hypothesized to attenuate shifts in the typology of whole muscle fibres from slow- to fast-twitch fibres in atrophied skeletal muscles. We further postulated that the prevention of slow-to-fast fibre shifts would suppress the decreased muscle endurance associated with atrophy. To evaluate the protective effects of R30, we analysed slow-to-fast fibre shifts and disuse-associated reduced muscle endurance. R30 was administered to rats with an acclimation period of 7 days before hindlimb unloading (HU) for 2 weeks. The composition ratio of the fibre type and the expression levels of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), calcineurin and nuclear factor of activated T-cells (NFAT) were measured. Muscle endurance was evaluated at the end of the 2-week HU period in an in situ environment. R30 supplementation suppressed the slow-to-fast fibre switch and decreased the HU-induced expression of PGC-1α proteins and the deactivation of the calcineurin-NFAT pathway. Furthermore, R30 prevented a decrease in HU-associated muscle endurance in calf muscles. These results indicate that R30 supplementation may attenuate the shifts in the typology of whole muscle fibres from slow- to fast-twitch fibres via the upregulation of PGC-1α and the activation of the calcineurin-NFAT signalling pathway, thereby ameliorating the decrease in muscle endurance associated with disuse.

Effect of exercise therapy combined with branched-chain amino acid supplementation on muscle strength in elderly women after total hip arthroplasty: a randomized controlled trial.

BACKGROUND AND OBJECTIVES: Many patients develop a prolonged decrease of muscle strength after total hip arthroplasty (THA) despite their reconstructed hip joint. Physical exercise combined with branched-chain amino acid (BCAA) supplementation has been reported to improve muscle strength in elderly persons with sarcopenia. However, the effect of BCAA supplementation in patients after THA is unknown. This study examined the effects of BCAA supplementation combined with exercise therapy on the improvement of physical function in elderly patients after THA. METHODS AND STUDY DESIGN: The subjects were 31 elderly women who underwent THA. The participants were randomly assigned to two groups: BCAA (n=18) and control (n=13). The combined therapy was carried out for one month after THA. For the exercise intervention, a 3-set physical exercise program was conducted. For the nutritional intervention, the participants consumed 3.4 g of BCAA supplement or 1.2 g of starch immediately after the exercise intervention. RESULTS: BCAA supplementation combined with muscle strengthening exercises had a significant effect on knee extension strength of the contralateral side and on upper arm cross-sectional area. The improvement ratio of knee extension strength before and after intervention on the operated side was also significantly higher in the BCAA group. CONCLUSIONS: BCAA supplementation is effective for patients to improve the strength of some muscles when combined with physical exercises, but hip abductor muscle strength of the operated leg did not improve. A future study is needed to determine the efficacy of this combined therapy for hip abductor muscle strength.

Effects of astaxanthin supplementation and electrical stimulation on muscle atrophy and decreased oxidative capacity in soleus muscle during hindlimb unloading in rats.

The effects of a combination of the antioxidant astaxanthin (AX) and electrical stimulation (ES) on muscle mass and mitochondrial oxidative capacity were investigated in the soleus muscle of hindlimb unloaded rats. Five groups of male Sprague-Dawley rats were used; control, 1-week hindlimb unloading (HU), HU + AX, HU + ES, and HU + AX + ES. Respective rats in the AX groups received 50-mg/kg AX twice daily during HU. Calf muscles of rats in the ES groups were electrically stimulated for 240 s/day during HU. One-week HU decreased muscle mass along with decreased FoxO3a phosphorylation and increased ubiquitinated proteins expressions, decreased oxidative enzymatic activity accompanied with decline in PGC-1α protein expression, and increased reactive oxygen species production. However, the combination treatment could synergistically attenuate/suppress all HU-related changes, suggesting protective effects on muscle atrophy and decreased muscle oxidative capacity due to chronic neuromuscular inactivity.

Preventive effects of nucleoprotein supplementation combined with intermittent loading on capillary regression induced by hindlimb unloading in rat soleus muscle.

Physical inactivity leads to muscle atrophy and capillary regression in the skeletal muscle. Intermittent loading during hindlimb unloading attenuates the muscle atrophy, meanwhile the capillary regression in the skeletal muscle is not suppressed. Nucleoprotein has antioxidant capacity and may prevent capillary regression. Therefore, we assessed the combined effects of intermittent loading with nucleoprotein supplementation on capillary regression induced by hindlimb unloading. Five groups of rats were assigned: control (CON), 7 days hindlimb unloading (HU), HU plus nucleoprotein supplementation (HU + NP), intermittent loading during HU (HU + IL), and intermittent loading combined with nucleoprotein supplementation during HU (HU + IL + NP). Seven days HU resulted in decrease in capillary number-to-fiber number (C/F) ratio accompanied with disuse-associated changes in fetal liver kinase-1 (Flk-1), a proangiogenesis factor, and thrombospondin-1 (TSP-1), an antiangiogenesis factor, in the soleus muscle. In addition, citrate synthase (CS) activity was decreased and protein level of superoxide dismutase (SOD)-2 was increased. Neither nucleoprotein supplementation nor intermittent loading prevented the decrease in the C/F ratio, whereas nucleoprotein supplementation combined with intermittent loading prevented the regression of capillary during unloading. Moreover, the levels of Flk-1, TSP-1, and SOD-2 protein and the CS activity were maintained up to control levels. These results suggested that nucleoprotein supplementation combined with intermittent loading was effective to prevent capillary regression induced by muscle atrophy.

Nucleoprotein supplementation enhances the recovery of rat soleus mass with reloading after hindlimb unloading-induced atrophy via myonuclei accretion and increased protein synthesis.

Hindlimb unloading results in muscle atrophy and a period of reloading has been shown to partially recover the lost muscle mass. Two of the mechanisms involved in this recovery of muscle mass are the activation of protein synthesis pathways and an increase in myonuclei number. The additional myonuclei are provided by satellite cells that are activated by the mechanical stress associated with the reloading of the muscles and eventually incorporated into the muscle fibers. Amino acid supplementation with exercise also can increase skeletal muscle mass through enhancement of protein synthesis and nucleotide supplements can promote cell cycle activity. Therefore, we hypothesized that nucleoprotein supplementation, a combination of amino acids and nucleotides, would enhance the recovery of muscle mass to a greater extent than reloading alone after a period of unloading. Adult rats were assigned to 4 groups: control, hindlimb unloaded (HU; 14 days), reloaded (5 days) after hindlimb unloading (HUR), and reloaded after hindlimb unloading with nucleoprotein supplementation (HUR + NP). Compared with the HUR group, the HUR + NP group had larger soleus muscles and fiber cross-sectional areas, higher levels of phosphorylated rpS6, and higher numbers of myonuclei and myogenin-positive cells. These results suggest that nucleoprotein supplementation has a synergistic effect with reloading in recovering skeletal muscle properties after a period of unloading via rpS6 activation and satellite cell differentiation and incorporation into the muscle fibers. Therefore, this supplement may be an effective therapeutic regimen to include in rehabilitative strategies for a variety of muscle wasting conditions such as aging, cancer cachexia, muscular dystrophy, bed rest, and cast immobilization.

Effectiveness of daily eccentric contractions induced via kilohertz frequency transcutaneous electrical stimulation on muscle atrophy.

The effects of daily repeated bouts of concentric, isometric, or eccentric contractions induced by high frequency (kilohertz) transcutaneous electrical stimulation in ameliorating atrophy of the soleus muscle in hindlimb unloaded rats were determined. Five groups of male rats were studied: control, hindlimb unloaded for 2 weeks (HU), or HU plus two daily bouts of concentric, isometric, or eccentric high-frequency electrical stimulation-induced contractions of the calf musculature. Soleus mass and fiber size were smaller, the levels of phosphorylated Akt1 and FoxO3a lower, and atrogin-1 and ubiquitinated proteins higher in the HU, and the HU plus concentric or isometric contraction groups than in the control group. In contrast, daily bouts of eccentric contractions maintained these values at near control levels and all measures were significantly different from all other HU groups. These results indicate that daily bouts of eccentric contractions induced by high-frequency stimulation inhibited the ubiquitin-proteasome catabolic pathway and enhanced the Akt1/FoxO3a anabolic pathway that resulted in a prevention of the atrophic response of the soleus muscle to chronic unloading.