Lower capillarization, VEGF protein, and VEGF mRNA response to acute exercise in the vastus lateralis muscle of aged vs. young women

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Kevin Zwetsloot Ph.D, Associate Professor (Creator)
Appalachian State University (ASU )
Web Site: https://library.appstate.edu/

Abstract: In humans, the majority of studies demonstrate an age-associated reduc- tion in the number of capillaries surrounding skeletal muscle fibers; however, recent reports in rats suggest that muscle capillarization is well maintained with advanced age. In sedentary and trained men, aging lowers the number of capillaries surrounding type II, but not type I, skeletal muscle fibers. The fiber type-specific effect of aging on muscle capillarization is unknown in women. Vascular endothelial growth factor (VEGF) is important in the basal maintenance of skeletal muscle capillarization, and lower VEGF expression is asso- ciated with increased age in nonskeletal muscle tissue of women. Compared with young women (YW), we hypothesized that aged women (AW) would demonstrate 1) lower muscle capillarization in a fiber type-specific manner and 2) lower VEGF and VEGF receptor expression at rest and in response to acute exercise. Nine sedentary AW (70 + 8 yr) and 11 YW (22 + 3 yr) had vastus lateralis muscle biopsies obtained before and at 4 h after a submaximal exercise bout for the measurement of morphometry and VEGF and VEGF receptor expression. In AW compared with YW, muscle capillary contacts were lower overall (YW: 2.36 + 0.32 capillaries; AW: 2.08 + 0.17 capillaries), specifically in type II (YW: 2.37 + 0.39 capillaries; AW:1.91 + 0.36 capillaries) but not type I fibers (YW: 2.36 + 0.34 capillaries; AW: 2.26 + 0.24 capillaries). Muscle VEGF protein was 35% lower at rest, and the exercise-induced increase in VEGF mRNA was 50% lower in AW compared with YW. There was no effect of age on VEGF receptor expression. These results provide evidence that, in the vastus lateralis of women, 1) capillarization surrounding type II muscle fibers is lower in AW compared with YW and 2) resting VEGF protein and the VEGF mRNA response to exercise are lower in AW compared with YW.

Additional Information

Andrea N. Croley, Kevin A. Zwetsloot, Lenna M. Westerkamp, Nicholas A. Ryan, Angela M. Pendergast, Robert C. Hickner, Walter E. Pofahl and Timothy P. Gavin (2005) "Lower capillarization, VEGF protein, and VEGF mRNA response to acute exercise in the vastus lateralis muscle of aged vs. young women" Journal of Applied Physiology vol. 99 pp.1872-1879 Version of Record available @ (doi:10.1152/japplphysiol.00498.2005.)
Language: English
Date: 2005
kinase insert domain-containing receptor, Flt-1, fiber cross-sectional area, vascular endothelial growth factor

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