Skeletal muscle wastage in Crohnʹs disease: A pathway shared with heart failure?

Background Lean body mass wastage in active Crohnʹs disease is not only related to malnutrition, but also to local and systemic inflammation. Altered bowel permeability can represent a source of pro-inflammatory cytokines, that have been shown to produce muscle wastage by several mechanisms such as apoptosis. In our study we have evaluated the body composition and the pathological changes of skeletal muscle in patients with Crohnʹs disease to see whether a relationships between altered gut permeability, proinflammatory cytokines production and muscle wastage existed. Methods Thirteen consecutive steroid-free patients with active Crohnʹs disease underwent evaluation of body composition, sugar test for intestinal permeability, determination of serum levels of TNF-α, sphingosine, bacterial lipopolysaccaride, and biopsy of gastrocnemius. In bioptic samples we determined fibres cross sectional area, distribution of myosin heavy chains and apoptosis. Twenty healthy subjects formed the control group. Results In patients lean body mass was reduced and intestinal permeability increased (p < 0.01 for both). TNFα, sphingosine and lipopolysaccaride were increased (p < 0.01). Fibres size was reduced (p < 0.01), with shift of Myosin Heavy Chains from the slow to the fast type. Apoptosis was found in 5 patientsʹ biopsies, never in controls. Conclusions Crohnʹs patients have a myopathy characterized by myocyte apoptosis, modifications of myosin and muscle atrophy. TNF-α and sphingosine, that are increased because of the enhanced lipopolysaccaride concentration due to altered gut permeability, may play a pathophysiological role in the development of this myopathy.