Biomedical subjects

Stephen H LaFranchi

Publications and source records attributed to Stephen H LaFranchi.

4 recordsLinked to original sources

PubMed2003

Serum ghrelin levels are inversely correlated with body mass index, age, and insulin concentrations in normal children and are markedly increased in Prader-Willi syndrome.

Ghrelin, an endogenous ligand of the GH secretagogue receptor, stimulates appetite and causes obesity in animal models and in humans when given in pharmacologic doses. Prader-Willi Syndrome (PWS) is a genetic obesity syndrome characterized by GH deficiency and the onset of a voracious appetite and obesity in childhood. We, therefore, hypothesized that ghrelin levels may play a role in the expression of obesity in this syndrome. We measured fasting serum ghrelin levels in 13 PWS children with an average age of 9.5 yr (range, 5-15) and body mass index (BMI) of 31.3 kg/m2 (range, 22-46). The PWS group was compared with 4 control groups: 20 normal weight controls matched for age and sex, 17 obese children (OC), and 14 children with melanocortin-4 receptor mutations (MC4) matched for age, sex, and BMI, and a group of 3 children with leptin deficiency (OB). In non-PWS subjects, ghrelin levels were inversely correlated with age (r = 0.36, P = 0.007), insulin (r = 0.55, P < 0.001), and BMI (r = 0.62, P < 0.001), but not leptin. In children with PWS, fasting ghrelin concentrations were not significantly different compared with normal weight controls (mean +/- SD; 429 +/- 374 vs. 270 +/- 102 pmol/liter; P = 0.14). However, children with PWS did demonstrate higher fasting ghrelin concentrations (3- to 4-fold elevation) compared with all obese groups (OC, MC4, OB) (mean +/- SD; 429 +/- 374 vs. 139 +/- 70 pmol/liter; P < 0.001). In conclusion, ghrelin levels in children with PWS are significantly elevated (3- to 4-fold) compared with BMI-matched obese controls (OC, MC4, OB). Elevation of serum ghrelin levels to the degree documented in this study may play a role as an orexigenic factor driving the insatiable appetite and obesity found in PWS.

Adolescent↗

PubMed2003

Effects of growth hormone on pulmonary function, sleep quality, behavior, cognition, growth velocity, body composition, and resting energy expenditure in Prader-Willi syndrome.

The objective of this study was to investigate the effects of GH administration on pulmonary function, sleep, behavior, cognition, linear growth velocity, body composition, and resting energy expenditure (REE) in children with Prader-Willi syndrome. The study used a 12-month, balanced, randomized, double-blind, placebo-controlled, cross-over experimental design. Twelve subjects were randomized to GH (0.043 mg/kg x d) or placebo intervention for 6 months and then crossed over to the alternate intervention for 6 months. Differences in outcome variables were determined by paired t tests. Peak flow rate, percentage vital capacity, and forced expiratory flow rate improved and number of hypopnea and apnea events and duration of apnea events trended toward improvement after GH intervention. The only difference in cognition or behavior was an increase in hyperactivity scale on the Behavior Assessment System for Children after GH intervention. Linear growth velocity, REE, and lean mass were higher (67%, 19%, and 7.6%, respectively), and fat mass and percentage body fat were lower (10.3% and 8.1%, respectively) after GH intervention. GH administration did not change mean fasting ghrelin concentration. GH intervention improved body composition and REE and may contribute to better sleep quality and pulmonary function. GH administration did not impact fasting ghrelin concentration.

Adolescent↗

PubMed2003

Circulating ghrelin levels are suppressed by meals and octreotide therapy in children with Prader-Willi syndrome.

Prader-Willi syndrome (PWS) is characterized by severe obesity, hyperphagia, hypogonadism, and GH deficiency. Unlike individuals with common obesity, who have low fasting-plasma ghrelin concentrations, those with PWS have high fasting-ghrelin concentrations that might contribute to their hyperphagia. Treatment with octreotide, a somatostatin agonist, decreases ghrelin concentrations in healthy and acromegalic adults and induces weight loss in children with hypothalamic obesity. This pilot study was performed to determine whether octreotide administration (5 microg/kg.d) for 5-7 d lowers ghrelin concentrations and affects body composition, resting energy expenditure, and GH markers in children with PWS. Octreotide treatment decreased mean fasting plasma ghrelin concentration by 67% (P < 0.05). Meal-related ghrelin suppression (-35%; P < 0.001) was still present after intervention but was blunted (-11%; P = 0.19). Body weight, body composition, leptin, insulin, resting energy expenditure, and GH parameters did not change. However, one subject's parent noted fewer tantrums over denial of food during octreotide intervention. In conclusion, short-term octreotide treatment markedly decreased fasting ghrelin concentrations in children with PWS but did not fully ablate the normal meal-related suppression of ghrelin. Further investigation is warranted to determine whether long-term octreotide treatment causes sustained ghrelin suppression, changes eating behavior, and induces weight loss in this population.

Behavior↗

PubMed2002

Adolescent thyroid disorders.

Thyroid disorders are common in adolescence. Thyroid nodules can present in this age group, and although most are benign, malignancy is not unheard of. Chronic lymphocytic thyroiditis can present as hypothyroidism, while the adolescent with a goiter due to autoimmune thyroid disease is frequently euthyroid. Graves disease is a common etiology of hyperthyroid presentation in this age group. While there are known genetic and iatrogenic conditions that may predispose thyroid problems, they may also happen randomly in the general population. Thyroid problems may present as a goiter, a nodule, or a general cluster of abnormal symptoms and physical findings. The unique challenge to the provider of adolescent health care is that thyroid problems can adversely affect growth and development during puberty, a crucial period of hormonal interaction. This chapter addresses the diagnosis, treatment alternatives, and prognosis for a variety of common and uncommon thyroid abnormalities in adolescents. Many are readily treatable if recognized promptly, and even thyroid cancer often can be effectively treated and managed. Physicians treating the adolescent population have to be aware of the various thyroid problems that their patients can face.

Adolescent↗