A reduced response of older skeletal muscle to anabolic stimuli may contribute to the development of sarcopenia. We hypothesized that muscle proteins are resistant to the anabolic action of insulin in the elderly. We examined the effects of hyperinsulinemia on muscle protein metabolism in young (25±2 year) and older (68±1 year) healthy subjects using stable isotope tracer techniques. Leg blood flow was higher in the young at baseline and increased during hyperinsulinemia, whereas it did not change in the elderly. Glucose concentrations and muscle uptake were not different between groups at baseline and during hyperinsulinemia. Leg phenylalanine net balance was not different at baseline and significantly increased in both groups with hyperinsulinemia (P<0.05) but to a greater extent in the young (P<0.05). Muscle protein synthesis increased only in the young during hyperinsulinemia. Muscle protein breakdown did not significantly change in either group, although it tended to decrease in the elderly. Changes in muscle protein synthesis were correlated with changes in leg amino acid delivery (R=0.89; P=0.0001) and blood flow (R=0.90; P<0.0001). In conclusion, skeletal muscle protein synthesis is resistant to the anabolic action of insulin in older subjects, which may be an important contributor to the development of sarcopenia.Keywords skeletal muscle; hyperinsulinemia; leg blood flow; phenylalanine Aging is associated with a progressive loss of physical independence, which significantly worsens the quality of life and increases morbidity and mortality. A fundamental cause of and contributor to disability in older people is the involuntary loss of muscle mass and strength (sarcopenia), which eventually reduces function (1-3), thus increasing the risk of falls and vulnerability to injury (4,5). Sarcopenia is most likely a multifactorial disorder (1,6), and recent evidence suggests that a decreased response of muscle protein synthesis to anabolic stimuli may be involved (7-9).Previous studies had suggested that sarcopenia may be due to a reduced basal rate of muscle protein synthesis (10-14), but we have recently reported in the largest cohort of healthy men to date that despite a decline in muscle mass, basal rates of muscle protein synthesis and net NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript balance are not reduced with healthy aging (15). We have also found that aging is not associated with a reduced anabolic response of muscle to amino acids, as they stimulate muscle protein synthesis in the elderly to the same extent as in the young regardless of oral or intravenous administration route (16)(17)(18)(19)(20). However, we have recently shown that whereas the addition of carbohydrate to an amino acid meal enhanced the amino acid stimulation of muscle protein synthesis in young subjects (7,21), in older subjects such a combination did not have any additive effect on muscle protein synthesis (7). On the contrary, it blunted the amino acidinduced increase in muscle protein synthes...

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The last decade has seen a significant increase in the use of endovascular procedures and a decrease in rates of major amputation. These trends are seen both for patients admitted with acute PAD, as well as in the population in general. While our study was not designed to demonstrate a causal relationship, our findings suggest an association between increased application of endovascular technology and reduced rates of amputation in patients with PAD.

BVT frequently do not mature in patients older than 60 years, which compromises its utility as a primary access. However, fistulas that mature provide acceptable patency rates, and subsequent conversion to a prosthetic access is frequently possible. Selective use of BVT might improve the utilization of available access sites.

CO(2)-DSA is safe, can be used to guide EVAR, and provides outcomes similar to ICA-guided EVAR. CO2-DSA protects renal function in the azotemic patient by lessening the need for iodinated contrast and associated nephrotoxicity, but with the tradeoff of longer fluoroscopy and operating room times and increased radiation exposure.