Magnesium Abnormalities of Skeletal Muscle in Dermatomyositis and Juvenile Dermatomyositis
Arthritis & RheumatismLow levels of ATP-bound magnesium and free magnesium may play a significant role in the pathophysiology of both adult and juvenile dermatomyositis.
This is the finding of a study by Kenneth J. Niermann and colleagues from Vanderbilt University School of Medicine, Nashville, Tennessee, United States. They aimed to characterise abnormalities in magnesium levels in people with these diseases and evaluating the beneficial effects of prednisone and immunosuppressive therapy in raising free magnesium and ATP-bound magnesium (Mg-ATP).
There were two study groups: 12 adult patients with dermatomyositis (DM) and 10 young people with juvenile dermatomyositis (JDM). One control group consisted of 11 normal adults and the other of six healthy children.
Researchers used noninvasive P-31 magnetic resonance spectroscopy (MRS) to determine levels of total ATP in the quadriceps muscles of the subjects during rest, exercise, and recovery. Concentrations of the biologically active free magnesium and the enzymatically active Mg-ATP complex were determined from the spectroscopy data via calculation of the chemical shifts of the beta-phosphate peak of ATP.
The study found Mg-ATP levels in both DM and JDM myopathic muscles were at least 37 percent lower than those in normal muscles during rest, exercise and recovery from exercise. Although free magnesium levels were normal in DM and JDM myopathic muscles at rest, they were significantly lower than control values during exercise and recovery.
Prednisone and immunosuppressive therapy partially reversed the magnesium abnormalities, as evidenced by elevation of the levels of Mg-ATP and free magnesium.
Low levels of Mg-ATP and free magnesium are concordant with weakness and fatigue observed in DM and JDM patients; immunosuppressive therapy alleviates, in part, the magnesium deficits in the diseased muscles.
Arthritis & Rheumatism Volume 46, Issue 2, 2002.
Pages: 475-488.
"Magnesium abnormalities of skeletal muscle in dermatomyositis and juvenile dermatomyositis"
