IPSCs, a promising tool to restore muscle atrophy

Induced pluripotent stem cells (iPSCs) are a promising tool for regenerative medicine in chronic conditions associated with muscle atrophy since iPSCs are easier to obtain, pose less ethical limitations and can better capture human genetic diversity compared with human embryonic stem cells. We highlight the potentiality of iPSCs for treating muscle-affecting conditions for which no effective cure is yet available, notably aging sarcopenia and inherited neurometabolic conditions

Trace elements and electrolytes in human resting mixed saliva after exercise

Objectives—Exercise is known to cause changes in the concentration of salivary components such as amylase, Na, and Cl. The aim of this investigation was to evaluate the eVect of physical exercise on the levels of trace elements and electrolytes in whole (mixed) saliva. Methods—Forty subjects performed a maximal exercise test on a cycle ergometer. Samples of saliva were obtained before and immediately after the exercise test. Sample concentrations of Fe, Mg, Sc, Cr, Mn, Co, Cu, Zn, Se, Sr, Ag, Sb, Cs, and Hg were determined by inductively coupled plasma mass spectrometry and concentrations of Ca and Na by atomic absorption spectrometry. Results—After exercise, Mg and Na levels showed a significant increase (p<0.05) while Mn levels fell (p<0.05). Zn/Cu molar ratios were unaVected by exercise. Conclusions—Intense physical exercise induced changes in the concentrations of only three (Na, Mg, and Mn) of the 16 elements analysed in the saliva samples. Further research is needed to assess the clinical implications of these findings.

Chronic inflammation inhibits GH secretion and alters the serum insulin-like growth factor system in rats

Adjuvant-induced arthritis in rats is associated with growth failure, hypermetabolism and accelerated protein breakdown. The aim of this work was to study the effects of adjuvant-induced arthritis on GH and insulin-like growth factor-I (IGF-I). Arthritis was induced by an intradermal injection of complete Freund's adjuvant and rats were killed 18 and 22 days later. IGF-I and GH levels were measured by radioimmunoassay. Pituitary GH mRNA was analyzed by northern blot and IGF binding proteins (IGFBPs) by western blot. Arthritic rats showed a decrease in both serum and hepatic concentrations of IGF-I. On the contrary, arthritis increased the circulating IGFBPs. The serum concentration of IGF-I in the arthritic rats was negatively correlated with the body weight loss observed in these animals. Arthritis decreased the serum concentration of GH and this decrease seems to be due to an inhibition of GH synthesis, since pituitary GH mRNA content was decreased in arthritic rats (p<0.01). These data suggest that the decrease in body weight gain in arthritic rats may be, at least in part, secondary to the decrease in GH and IGF-I secretion. Furthermore, the increased serum IGFBPs may also be involved in the disease process.

Determination of the maximum steady state of lactate (MLSS) in saliva: An alternative to blood lactate determination

Based on previous research which shows parallelism between the saliva and blood lactate response during incremental exercise, we hypothesized that a "maximum salivary lactate steady state" (saliva-MLSS) might exist. Thus, the aim of the present investigation was to establish 1) which lower limit for the increase in salivary lactate concentration during a constant workload (i.e., from the 10th to the 20th min) test could be used to determine the saliva-MLSS and 2) if the exercise intensity corresponding to the saliva-MLSS is identical to that evoking the (blood) MLSS. Twelve male amateur athletes of mean (+/-SD) age 24+/-5 year were selected for the study. Based on the results of a previous maximal cycle ergometer test for lactate threshold (LT) determination, each subject performed consecutive constant workload tests of 20-min duration on separate days for MLSS determination, Blood and saliva (25 mu l) samples were collected at 0, 10, and 20 min during the tests for lactate determination. A Student's t-test for paired data demonstrated that a salivary lactate increase of 0.8 mM corresponded to the saliva-MLSS. At this value, indeed, no significant differences were observed between the mean (V) over dot O-2, and W values corresponding to the MLSS and the saliva-MLSS. In conclusion, the present findings indicate that 0.8 mM is the lower limit for the increase in saliva lactate concentration during a constant load test and thus is that which might be used as a reference to determine saliva-MLSS. Furthermore, saliva-MLSS might be used as an alternative to MLSS determination in blood samples.