Effects of Focused Vibrations on Human Satellite Cells.

Skeletal muscle consists of long plurinucleate and contractile structures, able to regenerate and repair tissue damage by their resident stem cells: satellite cells (SCs). Reduced skeletal muscle regeneration and progressive atrophy are typical features of sarcopenia, which has important health care implications for humans. Sarcopenia treatment is usually based on physical exercise and nutritional plans, possibly associated with rehabilitation programs, such as vibratory stimulation. Vibrations stimulate muscles and can increase postural stability, balance, and walking in aged and sarcopenic patients. However, the possible direct effect of vibration on SCs is still unclear. Here, we show the effects of focused vibrations administered at increasing time intervals on SCs, isolated from young and aged subjects and cultured in vitro. After stimulations, we found in both young and aged subjects a reduced percentage of apoptotic cells, increased cell size and percentage of aligned cells, mitotic events, and activated cells. We also found an increased number of cells only in young samples. Our results highlight for the first time the presence of direct effects of mechanical vibrations on human SCs. These effects seem to be age-dependent, consisting of a proliferative response of cells derived from young subjects vs. a differentiative response of cells from aged subjects.

Ecotoxicity of pristine graphene to marine organisms.

The ecotoxicity of pristine graphene nanoparticles (GNC1, PGMF) in model marine organisms was investigated. PGMF resulted more toxic than GNC1 to the bioluminescent bacterium Vibrio fischeri and the unicellular alga Dunaliella tertiolecta on the basis of EC50 values (end-points: inhibition of bioluminescence and growth, respectively). No acute toxicity was demonstrated with respect to the crustacean Artemia salina although light microscope images showed the presence of PGMF and GNC1 aggregates into the gut; a 48-h exposure experiment revealed an altered pattern of oxidative stress biomarkers, resulting in a significant increase of catalase activities in both PGMF and GNC1 1mg/L treated A. salina and a significant increase of glutathione peroxidase activities in PGMF (0.1 and 1mg/L) treated A. salina. Increased levels of lipid peroxidation of membranes was also observed in PGMF 1mg/L exposed A. salina.