Key result
ET-receptor inhibition increased leg blood flow significantly more in older men than in younger individuals (29% vs 10%, P<0.05), while 8 weeks of cycling training decreased leg vascular tone.
Why the study?
Does endothelin-1 mediate increased leg vascular tone in healthy older men, and is it reversible with 8 weeks of cycling training?
Does endothelin-1 mediate increased leg vascular tone in healthy older men, and is it reversible with 8 weeks of cycling training?
Absolute Event Rate: 29% vs 10%
p-value: p=<0.05
Increased baseline vascular tone in aging is partly mediated by endothelin, and 8 weeks of cycling training decreases leg vascular tone in older sedentary men.
Supports ET-1 role in age-related leg vascular tone; hypothesis-generating for training or antagonism, pending RCTs.
UNLABELLED: Advanced age is associated with a decreased leg blood flow and reduced physical activity. Endothelin (ET-1), a powerful vasoconstrictor, may play a role in the increased leg vascular tone in older men. objectives: to assess the ET-1-mediated vascular tone in the legs of healthy sedentary older men, both before and after 8 wk of exercise training. methods: in 8 younger subjects (19-50 yr) and 8 older men (67-76 yr), bilateral leg blood flow was measured using venous occlusion plethysmography before and after antagonizing ET-1 (using selective ET(A/B)-receptor antagonists). In older men, reversibility of the observations was assessed after 8 wk of cycling. results: ET-receptor inhibition increased leg blood flow significantly more in older men compared with younger individuals (29 +/- 9% and 10 +/- 4%, respectively, P < 0.05). Eight-week cycling training increased baseline blood flow in older men. The blood flow response to ET-receptor inhibition in older men was not affected by the training program (25 +/- 8%, P > 0.05 for comparison with pretraining). The flow ratio (blood flows infused leg/noninfused leg) decreased significantly by training from 26 +/- 8% to 7+3% (P < 0.05). CONCLUSION: the increased baseline vascular tone in aging is at least in part mediated by the endothelin. Eight-weeks cycling training in older sedentary men decreased leg vascular tone and seems to partly decrease the ET-1-mediated vascular tone.
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Thijssen et al. (2007) studied Healthy sedentary (n=16). ET-receptor inhibition and cycling training vs. Younger subjects (for age comparison) and pre-training baseline (for training comparison) was evaluated on Increase in leg blood flow following ET-receptor inhibition (p=<0.05). ET-receptor inhibition increased leg blood flow significantly more in older men than in younger individuals (29% vs 10%, P<0.05), while 8 weeks of cycling training decreased leg vascular tone.
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