Combined resistance and aerobic exercise intervention improves fitness, insulin resistance and quality of life in survivors of childhood haemopoietic stem cell transplantation with total body irradiation

Purpose: To investigate the effects of a supervised combined resistance and aerobic training programme on cardiorespiratory fitness, body composition, insulin resistance and quality of life (QoL) in survivors of childhood haematopoietic stem cell transplantation (HSCT) with total body irradiation (TBI). Participants: HSCT/TBI survivors (n = 20; 8 females). Mean (range) for age at study and time since HSCT/TBI was 16.7 (10.9‐24.5) and 8.4 (2.3‐16.0) years, respectively. Methods: After a 6‐month run‐in, participants undertook supervised 45‐ to 60‐minute resistance and aerobic training twice weekly for 6 months, with a 6‐month follow‐up. The following assessments were made at 0, 6 (start of exercise programme), 12 (end of exercise programme) and 18 months: Body composition via dual energy X‐ray absorptiometry, homeostatic model assessment of insulin resistance (HOMA‐IR), cardiorespiratory fitness (treadmill‐based peak rate of oxygen uptake (VO2 peak) test), QoL questionnaires (36‐Item Short Form Health Survey (SF‐36) and Minneapolis‐Manchester Quality of Life Instrument (MMQL). Results: Results expressed as mean (standard deviation) or geometric mean (range). There were significant improvements in VO2 peak (35.7 (8.9) vs 41.7 (16.1) mL/min/kg, P = 0.05), fasted plasma insulin (16.56 (1.48‐72.8) vs 12.62 (1.04‐54.97) mIU/L, P = 0.03) and HOMA‐IR (3.65 (0.30‐17.26) vs 2.72 (0.22‐12.89), P = 0.02) after the exercise intervention. There were also significant improvements in the SF‐36 QoL general health domain (69.7 (14.3) vs 72.7 (16.0), P = 0.001) and the MMQL school domain (69.1 (25.2) vs (79.3 (21.6), P = 0.03) during the exercise intervention. No significant changes were observed in percentage body fat, fat mass or lean mass. Conclusion: The supervised 6‐month combined resistance and aerobic exercise programme significantly improved cardiorespiratory fitness, insulin resistance and QoL in childhood HSCT/TBI survivors, with no change in body composition, suggesting a metabolic training effect on muscle. These data support a role for targeted physical rehabilitation services in this group at high risk of diabetes and cardiovascular disease

Obesity-associated GNAS mutations and the melanocortin pathway.

This is the final version. Available from Massachusetts Medical Society via the DOI in this record. BACKGROUND: GNAS encodes the Gαs (stimulatory G-protein alpha subunit) protein, which mediates G protein-coupled receptor (GPCR) signaling. GNAS mutations cause developmental delay, short stature, and skeletal abnormalities in a syndrome called Albright's hereditary osteodystrophy. Because of imprinting, mutations on the maternal allele also cause obesity and hormone resistance (pseudohypoparathyroidism). METHODS: We performed exome sequencing and targeted resequencing in 2548 children who presented with severe obesity, and we unexpectedly identified 22 GNAS mutation carriers. We investigated whether the effect of GNAS mutations on melanocortin 4 receptor (MC4R) signaling explains the obesity and whether the variable clinical spectrum in patients might be explained by the results of molecular assays. RESULTS: Almost all GNAS mutations impaired MC4R signaling. A total of 6 of 11 patients who were 12 to 18 years of age had reduced growth. In these patients, mutations disrupted growth hormone-releasing hormone receptor signaling, but growth was unaffected in carriers of mutations that did not affect this signaling pathway (mean standard-deviation score for height, -0.90 vs. 0.75, respectively; P = 0.02). Only 1 of 10 patients who reached final height before or during the study had short stature. GNAS mutations that impaired thyrotropin receptor signaling were associated with developmental delay and with higher thyrotropin levels (mean [±SD], 8.4±4.7 mIU per liter) than those in 340 severely obese children who did not have GNAS mutations (3.9±2.6 mIU per liter; P = 0.004). CONCLUSIONS: Because pathogenic mutations may manifest with obesity alone, screening of children with severe obesity for GNAS deficiency may allow early diagnosis, improving clinical outcomes, and melanocortin agonists may aid in weight loss. GNAS mutations that are identified by means of unbiased genetic testing differentially affect GPCR signaling pathways that contribute to clinical heterogeneity. Monogenic diseases are clinically more variable than their classic descriptions suggest. (Funded by Wellcome and others.).Wellcome TrustWellcome TrustResearch EnglandNational Institute for Health Researc

Counterregulation during spontaneous nocturnal hypoglycemia in prepubertal children with type 1 diabetes.

OBJECTIVE: To examine counterregulatory responses during spontaneous nocturnal hypoglycemia in prepubertal children with type 1 diabetes. RESEARCH DESIGN AND METHODS: A total of 29 prepubertal patients with type 1 diabetes underwent two overnight profiles. Data were analyzed from 16 children (median [range] 8.7 [5.9-12.9] years of age) with a night of hypoglycemia and a nonhypoglycemic night. Children hypoglycemic (< 3.5 mmol/l) on night 1 were given 25% extra carbohydrate as uncooked cornstarch with their usual evening snack on night 2 to avoid hypoglycemia. Glucose, growth hormone, and cortisol were measured every 15 min, catecholamines every 30 min, and glucagon, pancreatic polypeptide, insulin, and ketones every 60 min. A group of 15 healthy control subjects, aged 9.5 (5.6-12.1) years, underwent one overnight profile. RESULTS: Median duration of hypoglycemia was 225 (30-630) min, and glucose nadir was 2.0 (1.2-3.3) mmol/l. Insulin levels were not different on the two nights (P = 0.9, analysis of variance), but children with diabetes had higher insulin levels than normal control subjects between 2300 and 0300, maximal at 0200 (mean +/- SEM 57.4 +/- 5.7 vs. 31.6 +/- 5.0 pmol/l, P = 0.002). Peak epinephrine was higher on the night of hypoglycemia (0.98 [0.52-2.09] nmol/l) versus nonhypoglycemia (0.32 [0.21-0.62] nmol/l), P = 0.001, but norepinephrine (1.29 [1.07-2.64] vs. 1.26 [1.04-1.88] nmol/l, P = 0.5), glucagon (93 [64.2-125.6] vs. 100.5 [54.6-158] ng/l, P = 0.6), pancreatic polypeptide (410.2 [191-643.2] vs. 270.8 [158.2-777.8] ng/l, P = 0.5), and cortisol (513 [300-679] vs. 475 [235-739] nmol/l, P = 0.6) were not different. Glucose threshold for epinephrine release was very low, 1.9 +/- 0.2 mmol/l. There was a short-lived rise in growth hormone from 75-105 min after onset of hypoglycemia, maximal at 90 min (7.8 +/- 1.2 vs. 3.5 +/- 0.9 ng/ml, P = 0.02). CONCLUSIONS: The prolonged nature of nocturnal hypoglycemic episodes may be explained in part by defective counterregulation. The risk of nocturnal hypoglycemia needs to be reduced before intensification of insulin therapy can be contemplated in this age-group