Catabolic to anabolic transition during nutritional rehabilitation of female adolescents with anorexia nervosa

Anorexia nervosa (AN) is associated with profound changes in glucose homeostasis, activity of the GH-IGF-1 axis, and adipose tissue, bone, and protein metabolism. We aimed to characterize the transition from a catabolic to anabolic state during the nutritional rehabilitation of female adolescent inpatients with AN. The study comprised 41 patients (aged 15.6 ± 1.6 yr). Blood samples were obtained at the time of admission and upon attainment of target weight. A subgroup of 18 patients also had blood samples obtained during the early refeeding period. Changes in body mass index (BMI) and BMI-SDS during hospitalization (5.1 ± 2.0 mo) were positively correlated with changes in markers of anabolism including IGF-1 (r ¼ 0.424, P ¼ 0.006), procollagen type I N-terminal propeptide (P1NP) (r ¼ 0.375, P ¼ 0.016), klotho (r ¼ 0.468, P ¼ 0.002), and alkaline phosphatase (ALP) (r ¼ 0.051, P ¼ 0.001) and were negatively correlated with the change in cortisol levels (r ¼ -0.331, P ¼ 0.035). Furthermore, changes in markers of anabolism were intercorrelated. IGF-1 increased consistently throughout the study period (P < 0.001); however, other variables showed a biphasic pattern. During the early refeeding period, there was a decrease in C-terminal telopeptides of type I collagen (CTX-1) (P < 0.001), uric acid (P < 0.001), cortisol (P ¼ 0.056), fatty acid-binding protein 4 (FABP4) (P ¼ 0.04), and klotho (P ¼ 0.038) levels, whereas urea/creatinine ratio (UCR) (P ¼ 0.045) increased. During the later phase, there was an increase in ALP (P ¼ 0.039), insulin (P ¼ 0.04), homeostatic model assessment for insulin resistance (HOMA-IR) (P ¼ 0.06), and klotho levels (P ¼ 0.02). In conclusion, the early refeeding period was characterized by a decrease in markers of catabolism, whereas the later phase was characterized by an increase in anabolic markers. We suggest that IGF-1, UCR, and klotho may be used as markers of reversal of catabolism and shift toward anabolism in patients with severe malnutrition.