Low levels of somatomedin C in patients with the fibromyalgia syndrome. A possible link between sleep and muscle pain

Abstract

Objective. Fibromyalgia is a common syndrome of musculoskeletal pain and fatigue. Lacking distinctive tissue or laboratory correlations, it has often been considered a form of "psychogenic rheumatism.'' In the present study, the notion that the stage4 sleep anomaly typically seen in the fibromyalgia syndrome may disrupt growth hormone secretion was tested. Because growth hormone has a very short half-life, serum levels of somatomedin C were measured; somatomedin C is the major mediator of growth hormone's anabolic actions and is a prerequisite for normal muscle homeostasis.Methods. Serum levels of somatomedin C were measured in 70 female fibromyalgia patients and 55 healthy controls, using a peptide-specific radioimmunoassay.Results. Significantly lower levels of somatomedin C were observed in the fibromyalgia patients compared with controls (mean 2 SD 124.7 f 47 ng/ml versus 175.2 2 60 ng/ml; P = 0.OoooOl).

Sleep Disorders in Fibromyalgia Syndrome

“…Sleep disturbances may affect physiological healing mechanisms after muscle-tissue damage. This may alter the transmission of sensory stimuli from damaged muscle tissue to nervous system and enhance the perception of muscle pain [51]. About 90% of FM patients had inadequate GH response to exercise [45] and one-third significantly low circulating IGF-1 levels [51].…”

The neuroscience and endocrinology of fibromyalgia

“…For example, levels of plasma neuropeptide Y, a peptide co-localized with norepinephrine in the sympathetic nervous system, are low in patients with FMS (33,39). Another neuroendocrine system, the growth hormone axis, is abnormal in FMS patients (40,41). However, our understanding of how the growth hormone and HPA axes are interrelated in FMS is incomplete.…”

Neurobiological aspects of the chronic fatigue syndrome

“…This study supports the presence of a specific rather than generalised impairment of hypothalamo-pituitary responsiveness to stress; further studies focusing on specific neural inputs, for example testing growth hormone responses to apomorphine as a measure of dopaminergic activity would ascertain whether there is any discrete neural dysfunction mediating the impaired prolactin response to stress. We are also currently measuring somatomedin C levels, which have been reported as low in fibromyalgia [126].…”