Magnesium abnormalities of skeletal muscle in dermatomyositis and juvenile dermatomyositis
Version of Record online: 5 FEB 2002
Copyright © 2002 by the American College of Rheumatology
Arthritis & Rheumatism
Volume 46, Issue 2, pages 475–488, February 2002
How to Cite
Niermann, K. J., Olsen, N. J. and Park, J. H. (2002), Magnesium abnormalities of skeletal muscle in dermatomyositis and juvenile dermatomyositis. Arthritis & Rheumatism, 46: 475–488. doi: 10.1002/art.10109
- Issue online: 5 FEB 2002
- Version of Record online: 5 FEB 2002
- Manuscript Accepted: 1 OCT 2001
- Manuscript Received: 20 JUN 2001
- Medical Student Research award from the American College of Rheumatology
- Medical Scholar award from Vanderbilt University School of Medicine
- Arthritis Foundation
To characterize abnormalities in magnesium levels in the muscles of patients with dermatomyositis (DM) and juvenile dermatomyositis (JDM) and to evaluate the beneficial effects of prednisone and immunosuppressive therapy in elevating free magnesium (Mg2+) and ATP-bound magnesium (Mg-ATP).
The study groups consisted of 12 adult patients with DM and 10 juvenile patients with JDM. The 2 control groups were 11 normal adults and 6 healthy children. Levels of total ATP in the quadriceps muscles of the subjects were determined during rest, exercise, and recovery, using noninvasive P-31 magnetic resonance spectroscopy (MRS). Concentrations of the biologically active free Mg2+ and the enzymatically active Mg-ATP complex were determined from the spectroscopy data by calculation of the chemical shifts of the β-phosphate peak of ATP.
Mg-ATP levels in DM and JDM myopathic muscles were at least 37% lower than those in normal muscles during rest, exercise, and recovery from exercise (P < 0.0005). Free Mg2+ levels were normal in DM and JDM myopathic muscles at rest, but were significantly lower than control values during exercise and recovery (P < 0.029 and P < 0.005 for DM and JDM, respectively). Prednisone and immunosuppressive therapy partially reversed the magnesium abnormalities, as evidenced by elevation of the levels of Mg-ATP and free Mg2+.
Low levels of Mg-ATP and free Mg2+ are concordant with weakness and fatigue observed in DM and JDM patients. Immunosuppressive therapy alleviates, in part, the magnesium deficits in the diseased muscles. Therefore, Mg-ATP and free Mg2+ may play a significant role in the pathophysiology of these diseases.