The Uremic Environment and Muscle Dysfunction in Man and Rat

Vol. 103, No. 1, 2006

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Original Paper

The Uremic Environment and Muscle Dysfunction in Man and Rat
A.P. Harrison^a, A.H. Nielsen^b, I. Eidemak^c, S. Molsted^c, E.M. Bartels^d

^aInstitute of Anatomy and Physiology, The Royal Veterinary and Agricultural University, Frederiksberg,
^bDepartment of Nephrology, Herlev University Hospital, Herlev,
^cDialysis Ward, Hillerød Hospital, Hillerød, and
^dThe Danish Library of Science and Medicine, Copenhagen University, Copenhagen, Denmark

Address of Corresponding Author

Nephron Physiol 2006;103:p33-p42 (DOI: 10.1159/000090221)

Key Words

Uremia
Muscle dysfunction
Dialysis
Electromyography
Muscle strength

Abstract

Background: Patients reaching end-stage renal disease experience debilitating fatigue, with progression of this disease, rendering patients dysfunctional in their everyday lives. Methods: In vivomeasurements of muscle function, assessed using surface electromyography (EMG), were made on 25 patients prior to and after a session of hemodialysis (HD) treatment, alongsidein vitro measurements of muscle function in isolated rat muscles incubated in normal or uremic conditions approximating to those found in uremic rats (rat uremic: RU) or uremic humans (human uremic: HU). Results: HD significantly affected plasma values, e.g. reducing urea (69%), creatinine (62%), potassium (23%) and phosphate (48%) concentrations in patients (all p < 0.01). Treatment also improved the EMG frequency of 2nd dorsal interosseous (fast-twitch) (p < 0.01), although no change was noted for vastus lateralis (slow-twitch). In isolated rat muscles, a uremic environment had no significant effect on slow-twitch soleus during field stimulation, however, in fast-twitch extensor digitorum longus, a significant 23% (RU) and 22% (HU) faster rate of decline in force was measured, compared to controls (p < 0.001 and p < 0.01, respectively). Conclusion: It is concluded that (1) muscle weakness and its electrophysiological correlates may be rapidly induced by uremic solutes and rapidly reversed when the solutes are removed by dialysis, and (2) fast-twitch muscles are more readily affected by uremic conditions than slow-twitch muscles.

Author Contacts

Dr. A.P. Harrison
Institute of Anatomy and Physiology
The Royal Veterinary and Agricultural University
DK-1870 Frederiksberg C (Denmark)
Tel. +45 3528 2568, Fax +45 3528 2525, E-Mail adh@kvl.dk

Article Information

Received: June 8, 2005
Accepted: September 14, 2005
Published online: December 12, 2005
Number of Print Pages : 10
Number of Figures : 3, Number of Tables : 3, Number of References : 30

Medline Abstract (ID 16352915)

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