Does the exercise-regulated myokine chitinase-3-like protein 1 stimulate human myocyte proliferation?
Our findings suggest that CHI3L1 is induced by acute exercise and that CHI3L1/PAR-2 signalling activates myocyte proliferation, which is important for restructuring of skeletal muscle in the response to exercise training.
Levels of hs-CRP were far more enhanced in patients with PmAF compared to the controls. Plasma levels of NO(X) were significantly lower in PmAF patients than SR patients, but the production of NO(X) in the local right atrium increased obviously. Furthermore, iNOS and 3NT expressions increased dramatically in the right atrium in PmAF patients, whereas the expression of eNOS did not change apparently. In addition, when patients were further divided into a higher hs-CRP group (> or =5 mg/L) and a lower hs-CRP group (<5 mg/L) according to the hs-CRP level, significant upregulation of iNOS was found in the higher hs-CRP group. Apoptosis index and caspase 3 staining were also prominently enhanced in PmAF patients compared with SR patients. More importantly, we demonstrated in this study that a higher expression of 3NT was associated with an increased expression of iNOS/eNOS (r=0.74, P<0.05) and an enhanced apoptosis index (r=0.69, P<0.05). In conclusion, the results presented novel evidence that imbalanced expression of iNOS/eNOS could contribute to protein nitration and cardiomyocyte apoptosis in human AF, in which condition inflammation may be an important participant.