The genetic background and vitamin D supplementation can affect irisin levels in Prader-Willi syndrome.

BACKGROUND: Prader-Willi syndrome (PWS) is associated to distinctive clinical symptoms, including obesity, cognitive and behavioral disorders, and bone impairment. Irisin is a myokine that acts on several target organs including brain adipose tissue and bone. The present study was finalized to explore circulating levels of irisin in children and adult PWS patients. METHODS: Seventy-eight subjects with PWS, 26 children (15 females, mean age 9.48 ± 3.6 years) and 52 adults (30 females, mean age 30.6 ± 10.7) were enrolled. Irisin serum levels were measured in patients and controls. Its levels were related with anthropometric and metabolic parameters, cognitive performance and bone mineral density either in pediatric or adult PWS. Multiple regression analysis was also performed. RESULTS: Irisin serum levels in PWS patients did not show different compared with controls. A more in-depth analysis showed that both pediatric and adult PWS with DEL15 displayed significantly reduced irisin levels compared to controls. Otherwise, no differences in irisin concentration were found in UPD15 patients with respect to controls. Our study revealed that in pediatric PWS the 25(OH) vitamin-D levels affected irisin serum concentration. Indeed, patients who were not supplemented with vitamin D showed lower irisin levels than controls and patients performing the supplementation. Multiple regression analysis showed that irisin levels in pediatric and adult PWS were predicted by the genetic background and 25(OH)-vitamin D levels, whereas in a group of 29 adult PWS also by intelligent quotient. CONCLUSION: We demonstrated the possible role of genetic background and vitamin-D supplementation on irisin serum levels in PWS patients.

Growth hormone treatment improves final height and nutritional status of children with chronic kidney disease and growth deceleration.

PURPOSE: Growth retardation is a common complication of chronic kidney disease (CKD) in children. Treatment with recombinant human growth hormone (rhGH) has been used to help short children with CKD to attain a height more in keeping with their age group, but the scientific evidence regarding the effect of rhGH on final height is scarce. METHODS: Final heights of children with CKD receiving rhGH treatment (cases) were compared with final heights of a matched cohort of children with CKD that did not receive rhGH therapy (controls). RESULTS: Sixty-eight rhGH-treated cases (44 boys) were compared with 92 untreated controls (60 boys). Mean duration of rhGH therapy was 4.2 ± 0.9 years; rhGH dose was 0.3 ± 0.07 mg/kg/week. Height SDS at baseline was lower in rhGH-treated patients than in controls (-2.00 ± 1.02 versus -0.96 ± 1.11, p < 0.001). Baseline height SDS was significantly lower than target height SDS in both groups. Height SDS significantly improved from baseline to final height attainment in rhGH-treated patients, while it slightly decreased in controls (mean SDS variation 0.69 ± 1.05 in rhGH-treated cases versus -0.15 ± 1.2 in controls). Final height SDS was -1.25 ± 1.06 in rhGH-treated cases and -1.06 ± 1.17 in controls (p = 0.29). Target adjusted final height SDS was -0.91 ± 1.03 in rhGH-treated cases and -0.61 ± 1.17 in controls (p = 0.1). CONCLUSIONS: Long-term rhGH therapy is able to reduce the linear growth deceleration of children with CKD, and ultimately to improve their final height, reducing the difference with target height.