MECHANISMS OF LOSS OF LEAN BODY-MASS IN PATIENTS ON CHRONIC DIALYSIS

Patients on chronic dialysis treatment often have reduced lean body ma ss. Certain aspects of bio-incompatibility in dialysis can be viewed a s leading to a chronic inflammatory state, In most chronic inflammator y diseases, loss of mean body mass is independent of reduced caloric i ntake, However, reduced caloric intake accounts for most of the weight loss in these patients and also dialysis patients, Refeeding is assoc iated with increased fat deposition more than restoration of muscle ma ss, In addition to reduced caloric intake, patients with rheumatoid ar thritis, a classic example of a chronic inflammatory disease, have an elevated resting energy expenditure associated with decreased lean bod y mass. Elevated cellular tumor necrosis factor (TNF) and IL-1 beta pr oduction can be demonstrated in these patients. However, in many dialy sis patients, increased cytokine production can be 'normal' or reduced . This takes place as the level of malnutrition increases. Thus, cytok ines such as IL-1 and TNF play a decreasing role in the pathogenesis o f loss of body mass as malnutrition increases and curtails the synthes is of cytokines, Similar to patients with AIDS, progressive disease in patients on chronic dialysis may exhibit subclinical malnutrition whi ch leads to decreased cytokine production, Reduction in cytokine produ ction can be viewed as a protective mechanism.