Am. J. Respir. Crit. Care Med., Volume 160, Number 1, July 1999, 57-63

Skeletal Muscle Oxidative Capacity, Fiber Type, and Metabolites after Lung Transplantation

XIAO N. WANG, TREVOR J. WILLIAMS, MICHAEL J. MCKENNA, JIA L. LI, STEVEN F. FRASER, ELEONORA A. SIDE, GREGORY I. SNELL, E. HAYDN WALTERS, and MICHAEL F. CAREY

School of Life Science and Technology, Department of Human Movement, Recreation and Performance, Centre for Rehabilitation, Exercise and Sports Science, Victoria University of Technology, and Department of Respiratory Medicine, Alfred Hospital and Monash University, Melbourne, Australia

Lung transplant (LTx) recipients have a low peak work rate, peak oxygen consumption ( O₂peak), and early lactate threshold on incremental exercise. We hypothesized that LTx recipients have reduced oxidative function and altered fiber type proportion in peripheral skeletal muscle. Seven stable LTx recipients and seven age- and sex-matched control subjects were studied. Incremental exercise testing with arterialized venous sampling and a resting quadriceps femoris punch muscle biopsy were performed. Muscle specimens were analyzed for fiber type proportion, metabolites, oxidative and glycolytic enzyme activities, and mitochondrial ATP production rate (MAPR) using standard techniques. The results showed that mean O₂peak in LTx recipients was 52% of control subjects. Compared with the control subjects, LTx skeletal muscle exhibited: (1) a lower MAPR; (2) lower activity of the mitochondrial enzymes glutamate dehydrogenase (GDH), citrate synthase (CS), 2-oxogluterate dehydrogenase (OGDH), and 3-hydroxyacyl-CoA-dehydrogenase (HAD). There was no difference in the activities of anaerobic enzymes, except for higher phosphofructokinase activity; (3) a lower proportion of type I fibers; (4) a higher lactate and inosine monophosphate (IMP) content and a lower ATP content at rest indicating a high reliance on anaerobic metabolism. The reduced type I fiber proportion and severely reduced mitochondrial oxidative capacity may play an important role in exercise limitation after LTx.

This article has been cited by other articles:

				K. Guerrero, B. Wuyam, P. Mezin, I. Vivodtzev, M. Vendelin, J.-C. Borel, R. Hacini, O. Chavanon, S. Imbeaud, V. Saks, et al. Functional coupling of adenine nucleotide translocase and mitochondrial creatine kinase is enhanced after exercise training in lung transplant skeletal muscle Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2005; 289(4): R1144 - R1154. [Abstract] [Full Text] [PDF]

				S. Mathur, W D. Reid, and R. D Levy Exercise Limitation in Recipients of Lung Transplants Physical Therapy, December 1, 2004; 84(12): 1178 - 1187. [Full Text] [PDF]

				C Pinet, P Scillia, M Cassart, M Lamotte, C Knoop, C Melot, and M Estenne Preferential reduction of quadriceps over respiratory muscle strength and bulk after lung transplantation for cystic fibrosis Thorax, September 1, 2004; 59(9): 783 - 789. [Abstract] [Full Text] [PDF]

				K. R. Short, B. Drew, and C. Leeuwenburgh Mitochondrial ATP measurements Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2004; 287(1): R243 - R246. [Full Text] [PDF]

				M. J. McKenna, S. F. Fraser, J. L. Li, X. N. Wang, M. F. Carey, E. A. Side, J. Morton, G. I. Snell, K. Kjeldsen, and T. J. Williams Impaired muscle Ca2+ and K+ regulation contribute to poor exercise performance post-lung transplantation J Appl Physiol, October 1, 2003; 95(4): 1606 - 1616. [Abstract] [Full Text] [PDF]

				F. Laghi and M. J. Tobin Disorders of the Respiratory Muscles Am. J. Respir. Crit. Care Med., July 1, 2003; 168(1): 10 - 48. [Abstract] [Full Text] [PDF]

				H.R. Gosker, H. van Mameren, P.J. van Dijk, M.P.K.J. Engelen, G.J. van der Vusse, E.F.M. Wouters, and A.M.W.J. Schols Skeletal muscle fibre-type shifting and metabolic profile in patients with chronic obstructive pulmonary disease Eur. Respir. J., April 1, 2002; 19(4): 617 - 625. [Abstract] [Full Text] [PDF]