It has been reported that exercise with eccentric contractions can induce damage and inflammation in human muscle tissue, the severity of which depends on the duration and the intensity of exercise. Platelet activating factor (PAF) is a potent inflammatory mediator implicated in a series of pathophysiological conditions. We sought to investigate the relationship between PAF and eccentric exercise induced muscle damage. Thirteen healthy, recreationally active male subjects (27.5+/-3.78 year) performed 36 maximum voluntary eccentric contractions on a motorized muscle dynamometer using the elbow flexor muscles of the non-dominant arm. Venous blood samples were collected immediately before and after exercise at 2, 24, 48, 72 and 96 h. PAF was isolated, purified and determined by a platelet aggregation assay. Serum levels of creatine kinase (CK), lactate dehydrogenase (LDH), C-reactive protein (CRP) and complement C3 (C3), plasma level of fibrinogen and whole blood level of leukocytes (and their subsets) were determined. Established indicators of muscle damage as maximum isometric torque (MIT), range of motion (ROM), relaxed arm angle (RANG), flexed arm angle (FANG), arm circumference (CIRC) and muscle soreness were also measured at the same time points. PAF, leukocytes, CK and LDH were elevated after exercise, while other biochemical parameters such as CRP, C3 and fibrinogen were unchanged. We also observed an inverse association between PAF and MIT and ROM, as well as a positive association with other markers of muscle injury, i.e. CK, LDH, FANG and CIRC (all P's<0.05). Our findings may imply a role for PAF in the mechanism of eccentric exercise induced muscle damage.
Background: Hypertension leads to many degenerative diseases, the most common being cardiovascular in origin. This study has been designed to estimate the prevalence of self-reported hypertension in a random nationwide sample of adult Greek population, while focus was set to the assessment of participants' nutritional habits in relation to their hypertension status.
Background: The strong causal role of hypercholesterolaemia on the progression of atherosclerosis and subsequently on the development of cardiovascular disease is well described. Main aim of this study was to evaluate the prevalence of self-reported hypercholesterolaemia and its relation to nutritional habits, in a representative nationwide sample of adult Greek population.
Inflammation and oxidative stress have been implicated in the mechanism of eccentric exercise-induced muscle injury. This study examined whether baseline serum levels of selenium (Se), a trace element that participates in both antioxidant and anti-inflammatory systems, affects the overall response to injury. Thirteen males performed 36 maximal eccentric actions with the elbow flexors of the non-dominant arm on a motorized dynamometer. Venous blood samples were collected immediately before and after exercise at 2, 24, 48, 72 and 96 hours. Established indicators of muscle damage such as maximum isometric torque (MIT), range of motion (ROM), relaxed arm angle (RANG), flexed arm angle (FANG), arm circumference (CIRC), muscle soreness and serum levels of creatine kinase (CK) and lactate dehydrogenase (LDH) were determined at the same time points. Baseline serum levels of Se were also measured. Complementary data regarding assessment of Se status were retrieved by the use of a semi-quantitative food frequency questionnaire. All measures changed significantly (p<0.05) after exercise. The main finding of this study was that baseline Se serum levels were associated inversely with CK, LDH and FANG and positively with MIT and ROM (p<0.05). These data suggest that beyond overt Se deficiency, suboptimal Se status possibly worsens muscle functional decrements subsequent to eccentric muscle contractions.
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