leptin and Hypophosphatemia

Refeeding syndrome (RS) is a potentially fatal condition that can occur following the re-introduction of nutrition after a period of starvation. Hypophosphataemia following the reintroduction of nutrition is often the only reliable biochemical marker of RS. Refeeding index (RI) generated from baseline insulin-like growth factor-1 (IGF-1) and leptin has been proposed as a useful biochemical marker for the identification of patients at risk of developing refeeding hypophosphataemia (RH).. A prospective study included 52 patients referred for parenteral nutrition (PN). The sensitivity and specificity of IGF-1 measured using a sensitive assay was compared to the RI in predicting the development of RH (a ≥ 30% drop in PO4 during the first 36-h of PN administration). Leptin and IGF-1 were analysed on baseline samples using a quantitative enzyme-linked immunoassay. Daily blood samples were collected from all patients for routine biochemistry for the full duration of PN administration.. High sensitivity IGF-1 measurement alone was comparable with the RI, using receiver-operating characteristic (ROC) curve analysis, with areas under the curve being 0.79 and 0.80, respectively, and superior to leptin alone (0.72) for predicting ≥ 30% drop in PO4. The cut-off value for IGF-1 that gave best sensitivity (91% [95% CI 75-98%]) and specificity (65% [95% CI 41-85%]) was 63.7 µg/L, with a likelihood ratio of 2.59.. Baseline IGF-1 is an objective, sensitive and specific biochemical marker in identifying patients who are at high risk of developing RH prior to PN administration and therefore may have a role in clinical practice.

Topics: Adult; Area Under Curve; Biomarkers; Enzyme-Linked Immunosorbent Assay; Female; Humans; Hypophosphatemia; Insulin-Like Growth Factor I; Leptin; Male; Malnutrition; Middle Aged; Parenteral Nutrition; Prognosis; Prospective Studies; Refeeding Syndrome; ROC Curve

The discovery of leptin, a hormone primarily involved in adaptation to fasting, led to an increased interest in appetite regulation and appetite-modulating hormones. Here, we present unique data from a case of extreme starvation and refeeding, showing changes in plasma concentrations of appetite-modulating and metabolic hormones as well as biochemical changes, and draw attention to the dangers of the refeeding syndrome.. We studied the refeeding period of a 44-day voluntary fast uncomplicated by underlying disease. Biochemical and hormonal variables were compared with 16 matched subjects such that the BMI range of the controls covered the entire spectrum for the index subject's recovering BMI.. Lack of calorie intake with free access to water resulted in 25% loss of body weight. Haemoconcentration was observed and feeding was started with a low sodium, hypocaloric liquid formulation. During early refeeding, marked hypophosphataemia, haemodilution and slight oedema developed. Vitamins B1, B12 and B6 were depleted while serum free fatty acids, ketone bodies and zinc levels were abnormally high; abnormal liver function developed over the first week. The hormonal profile showed low IGF-I and insulin levels, and elevated IGF-binding protein-1 concentrations. Appetite-regulating hormones were either very low (leptin and ghrelin) or showed no marked difference from the control group (peptide YY, agouti-related peptide, alpha-melanocyte-stimulating hormone, neuropeptide Y and pro-opiomelanocortin). Appetite was low at the beginning of refeeding and a transient increase in orexin and resistin was observed coincidently with an increase in subjective hunger.. Our study illustrates the potential dangers of refeeding and provides a comprehensive insight into the endocrinology of prolonged fasting and the refeeding process.

Topics: Adult; Blood Glucose; Body Composition; Body Weight; Eating; Fasting; Food, Formulated; Hormones; Humans; Hypophosphatemia; Leptin; Male; Metabolism; Peptide Hormones; Peptides; Vitamins; Water-Electrolyte Balance