Objective: To examine the relation of circulating appetite neuropeptides, CCK-8 sulphate (CCK-8s) and beta-endorphin, and the tumour necrosis factor-alpha (TNF-alpha) and soluble TNF receptors (sTNFR) to the anorexia and wasting associated with HIV-infection.
Design: Cross-sectional analysis.
Setting: A university-based HIV/AIDS ambulatory clinic in Madrid, Spain.
Participants: Thirty-six randomly selected AIDS patients without concomitant diseases or secondary infections were classified into two groups: 19 patients with wasting and 17 with normal body weight, and 18 healthy controls.
Measurements: Nutritional status was evaluated by anthropometry, laboratory parameters and self-report of appetite. Plasma levels of TNF-alpha and sTNFR proteins p55 (sTNFR-p55) and p75 (sTNFR-p75) were determined by enzyme immunoassay, whereas CCK-8s and beta-endorphin levels were measured by radioimmunoassay.
Results: AIDS patients with wasting had significantly higher plasma concentrations of CCK-8s, but lower levels of beta-endorphin when compared to well-nourished AIDS patients (P < 0.01) or controls (P < 0.001). Mean levels of TNF-alpha, and sTNFR-p55 and sTNFR-p75 were greater in AIDS patients with wasting than in asymptomatic AIDS patients or in controls. No significant association was observed between any of these circulating peptides and the parameters of malnutrition.
Conclusions: An activation of the TNF system, together with reciprocal changes in plasma concentrations of two neuropeptides with opposing appetite regulation, that is increased concentrations of CCK-8s but lower levels of beta-endorphin, are associated with the presence of HIV wasting. We hypothesize that these changes may contribute to the development of HIV wasting by producing a pathological inhibition of appetite.