IGF-I, IGF-I-binding proteins and GH-binding protein in malnourished elderly patients with inflammation receiving refeeding therapy.

Abstract

To investigate the mechanisms determining the success or failure of refeeding therapy in malnourished elderly patients with inflammation by studying changes in plasma IGF-I, GH-binding protein (GHBP) and IGF-binding protein (IGFBP) levels and IGFBP-3 proteolysis. We studied 15 severely malnourished hospitalized elderly patients. Weight, food intake, plasma albumin, transthyretin, C-reactive protein (CRP), orosomucoid, interleukin-6 (IL-6), IGF-I, intact and proteolytically degraded IGFBP-3 and GHBP levels were determined on admission and during refeeding therapy designed to increase food intake to 40 kcal/kg body weight per day (15% protein). Plasma IGF-I, IGFBP-3 and GHBP levels were significantly low for age on admission in all malnourished elderly patients. They increased in nine patients as nutritional status improved (albuminemia >30 g/l; transthyretinemia >200 mg/l or weight gain >5% of initial body weight) and levels of inflammation markers decreased (group 1). In contrast, plasma IGF-I, IGFBP-3 and GHBP levels remained low in six patients in whom nutritional status failed to improve and levels of inflammation markers increased (group 2). IGF-I showed greater variations than IGFBP-3 or GHBP with respect to nutritional status. High plasma CRP and IL-6 levels were associated with high levels of IGFBP-3 proteolysis. Efficient refeeding therapy was associated with a significant increase in IGF-I plasma levels. In patients with severe and persistent inflammation, high levels of proteolysis of IGFBP-3 may have contributed to the low plasma IGF-I levels, persistence of hypercatabolism and lack of improvement in nutritional status.