Lower capillary density but no difference in VEGF expression in obese vs. lean young skeletal muscle in humans

• Published in: Journal of applied physiology (1985) Vol. 98; no. 1; pp. 315 - 321
• Main Authors: Gavin, Timothy P, Stallings, Howard W., III, Zwetsloot, Kevin A, Westerkamp, Lenna M, Ryan, Nicholas A, Moore, Rebecca A, Pofahl, Walter E, Hickner, Robert C
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Am Physiological Soc 01.01.2005; American Physiological Society
• Subjects: Adult; Biological and medical sciences; Blood vessels; Capillaries - pathology; Capillaries - physiopathology; Exercise Test; Human subjects; Humans; Male; Medical sciences; Metabolic diseases; Muscle, Skeletal - blood supply; Muscle, Skeletal - pathology; Muscle, Skeletal - physiopathology; Muscular system; Obesity; Obesity - physiopathology; Organ Size; Oxygen - metabolism; Physical Exertion; Thinness - metabolism; Vascular Endothelial Growth Factor A - metabolism; Human; Vastus lateralis muscle; Obesity; maximal oxygen uptake; Nutrition disorder; exercise; Striated muscle; Density; Microcirculation; Vascular endothelium growth factor; Biopsy; vascular endothelial growth factor; kinase insert domain-containing receptor; Blood capillary; Circulatory system; Nutritional status; homeostasis model assessment; Biological receptor; Flt-1
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00353.2004

Departments of 1 Exercise and Sport Science, 2 Physiology, and 4 Surgery, and 3 Human Performance Laboratory, East Carolina University, Greenville, North Carolina Submitted 1 April 2004 ; accepted in final form 3 August 2004 Obesity is associated with lower skeletal muscle capillarization and lower insulin sensitivity. Vascular endothelial growth factor (VEGF) is important for the maintenance of the skeletal muscle capillaries. To investigate whether VEGF and VEGF receptor [kinase insert domain-containing receptor (KDR) and Flt-1] expression are lower with obesity, vastus lateralis muscle biopsies were obtained from eight obese and eight lean young sedentary men before and 2 h after a 1-h submaximal aerobic exercise bout for the measurement of VEGF, KDR, Flt-1, and skeletal muscle fiber and capillary characteristics. There were no differences in VEGF or VEGF receptor mRNA at rest between lean and obese muscle. Exercise increased VEGF (10-fold), KDR (3-fold), and Flt-1 (5-fold) mRNA independent of group. There were no differences in VEGF, KDR, or Flt-1 protein between groups. Compared with lean skeletal muscle, the number of capillary contacts per fiber was the same, but lower capillary density (CD), greater muscle cross sectional area, and lower capillary-to-fiber area ratio were observed in both type I and II fibers in obese muscle. Multiple linear regression revealed that 49% of the variance in insulin sensitivity (homeostasis model assessment) could be explained by percentage of body fat (35%) and maximal oxygen uptake per kilogram of fat-free mass (14%). Linear regression revealed significant relationships between maximal oxygen uptake and both CD and capillary-to-fiber perimeter exchange. Although differences may exist in CD and capillary-to-fiber area ratio between lean and obese skeletal muscle, the present results provide evidence that VEGF and VEGF receptor expression are not different between lean and obese muscle. kinase insert domain-containing receptor; Flt-1; exercise; homeostasis model assessment; maximal oxygen uptake; vascular endothelial growth factor Address for reprint requests and other correspondence: T. P. Gavin, 363 Ward Sports Medicine Bldg., East Carolina Univ., Greenville, NC 27858 (E-mail: gavint{at}mail.ecu.edu )