A noninvasive analysis of urinary musculoskeletal collagen metabolism markers from rhesus monkeys subject to chronic hypergravity

• Published in: Journal of applied physiology (1985) 2008-10, Vol.105 (4), p.1255-1261
• Main Authors: Martinez, D. A, Patterson-Buckendahl, P. E, Lust, A, Shea-Rangel, K. M, Hoban-Higgins, T. M, Fuller, C. A, Vailas, A. C
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Amino Acids - urine; Animals; Biological and medical sciences; Biomarkers - urine; Calcium; Calcium - urine; Centrifugation; Collagen - urine; Creatinine - urine; Eating; Fundamental and applied biological sciences. Psychology; Hydroxyproline - urine; Hypergravity; Macaca mulatta; Monkeys & apes; Musculoskeletal system; Musculoskeletal System - metabolism; Studies; Time Factors; Tissues; Urinalysis; Urine; Weightlessness Countermeasures
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00573.2007

1 Connective Tissue Physiology Laboratory, Department of Health and Human Performance, 2 Biomedical Engineering Program, Department of Mechanical Engineering, University of Houston, Houston, Texas; 3 Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California; 4 Center of Alcohol Studies, Rutgers, The State University of New Jersey, Piscataway, New Jersey; and 5 Office of the President, Idaho State University, Pocatello, Idaho Submitted 25 May 2007 ; accepted in final form 18 July 2008 A decrease in load-bearing activity, as experienced during spaceflight or immobilization, affects the musculoskeletal system in animals and humans, resulting in the loss of bone and connective tissue. It has been suggested that hypergravity (HG) can counteract the deleterious effects of microgravity-induced musculoskeletal resorption. However, little consensus information has been collected on the noninvasive measurement of collagen degradation products associated with enhanced load-bearing stress on the skeleton. The purpose of this study is to assess the urinary collagen metabolic profiles of rhesus monkeys ( Macaca mulatta ) during 1 ) 2 wk of basal 1 G (pre-HG), 2 ) 2 wk of HG (2 G), and 3 ) two periods of post-HG recovery (1 G). Urine was collected over a 24-h period from six individual rhesus monkeys. Hydroxyproline (Hyp) and collagen cross-links (hydroxylysylpyridinoline and lysylpyridinoline) were measured by reverse-phase HPLC. Urinary calcium, measured by atomic absorption, and creatinine were also assayed. The results indicate no changes in nonreducible cross-links and Hyp during HG. Collagen cross-link biomarker levels were significantly elevated during the 2nd wk of HG. Urinary calcium content was significantly lower during HG than during the 1-G control period, suggesting calcium retention by the body. We conclude that there is an adaptation of the nonhuman primate musculoskeletal system during hyperloading and that noninvasive measurements of musculoskeletal biomarkers can be used as indicators of collagen and mineral metabolism during HG and recovery in nonhuman primates. centrifugation; collagen cross-links; hydroxyproline; Macaca mulatta Address for reprint requests and other correspondence: D. A. Martinez, Connective Tissue Physiology Laboratory, Biomedical Engineering Program, Univ. of Houston, N207 D Engineering Bldg. 1, Houston, TX 77204-4006 (e-mail: ddam{at}uh.edu )