Effects of resistance training on arterial compliance and plasma endothelin-1 levels in healthy men.

Arterial compliance (AC) is an index of the elasticity of large arteries. Endothelial dysfunction has been reported to result in reduced arterial compliance, which represents increased arterial stiffness. A reduction in AC is elicited by high-intensity resistance training, however the mechanisms are obscure. Because a single bout of resistance exercise causes a transient increase in circulating plasma endothelin-1 in humans, some vasoconstrictors may play a role in the mechanisms. The present study aimed to investigate whether resistance training-induced decrease in AC is associated with changes in circulating vasoconstrictors levels in young men. Young sedentary men were assigned to control (n=5) or training (n=9) groups. The training group performed four-week high-intensity resistance training (weight training exercise; three sessions/week). We measured AC and plasma levels of endothelin-1, angiotensin II, and norepinephrine before and after intervention. Resistance training significantly decreased AC, whereas the changes in plasma levels of neither endothelin-1, nor angiotensin II, nor norepinephrine were significantly different between the control and the training groups. Moreover, we found no significant correlations between changes in circulating plasma levels (endothelin-1, angiotensin II, and norepinephrine) and in the AC. Despite of no alteration of the resting circulating plasma levels (endothelin-1, etc.), we cannot exclude a possibility that the tissue/local concentrations of vasoconstrictors (endothelin-1, etc.) around the vessels might be increased and also involved in a reduction of AC in the training group. Taken together, the present results suggest that circulating vasoconstrictors (endothelin-1, etc.) in plasma are not involved in a reduction in AC by the resistance training.

Effect of habitual exercise on urinary liver-type fatty acid-binding protein levels in middle-aged and older adults.

The purpose of this study was to examine the effect of habitual exercise on urinary liver-type fatty acid-binding protein (L-FABP), which can reflect the degree of various stresses on renal proximal tubule related to the progression of renal disease, in middle-aged and older adults. Cross-sectional and interventional approaches were used to comprehensively achieve this purpose. In the cross-sectional study, we investigated the relationship between physical activity levels and urinary L-FABP levels in 130 middle-aged and older adults. In the interventional study, subjects (n=31) were divided into two groups: exercise (n=19) and control group (n=12), whereby we examined the effects of 12-week aerobic exercise training on urinary L-FABP levels. The cross-sectional study showed that the urinary L-FABP levels were significantly lower in the higher physical activity group than in the lower physical activity group (P<.05). In the interventional study, 12-week aerobic exercise training significantly decreased urinary L-FABP levels (P<.01). Furthermore, the relative changes in urinary L-FABP levels were significantly correlated with the relative changes in physical activity levels and mean arterial pressure after intervention (r=-.374 and r=.530, respectively). Our results revealed that the urinary L-FABP levels were lower in the higher physical activity individuals, and aerobic exercise training decreased urinary L-FABP levels. These results suggest that habitual exercise appears to be associated with a decrease in the degree of several stresses on renal proximal tubule and to be beneficial for kidney health in middle-aged and older adults.

Antimetastatic efficacy of niosomal pentoxifylline and its combination with activated macrophages in murine B16F10 melanoma model.

The aims of the present study were a) to enhance the effectiveness of antimetastatic agent, Pentoxifylline (PTX) by encapsulation in niosomes and b) to investigate the anticancer activity by combination therapy involving activated macrophages and PTX solution/PTX niosomes. Niosomes were prepared by lipid film hydration method. Particle size distribution revealed bimodal distribution with median vesicle size of 462 nm. The entrapment efficacy of PTX niosomes was found to be 9.64%. A cumulative release of 82.43% from niosomal suspension was observed at the end of 21 hours. Intravenous administration of niosomal PTX (6 mg/kg and 10 mg/kg) resulted in significant reduction in lung nodules in an experimental metastatic B16F10 model suggesting accumulation of PTX in a distant target organ-lung. Light microscopic observations of histologic sections showed a decrease in number of tumor islands in the lung. Macrophages activated by intraperitoneal injection of Iscove's Modified Dulbecco's Medium (IMDM) containing 20% fetal calf serum (FCS) followed by in vitro incubation with muramyl dipeptide (MDP) were more effective in controlling tumor spread than those activated by FCS alone. Combination therapy of activated macrophages and PTX solution/niosomal PTX showed no additive or synergistic effect in controlling tumor spread. Carbon clearance studies revealed that PTX inhibits the phagocytic ability of activated macrophages, thereby resulting in the failure of combination therapy.