Bone & Mineral

Huaman Growth Hormone
Favorably Affects Bone
Turnover and Bone Mineral

Patients with short bowel syndrome (SBS) have a high prevalence of metabolic disease due to nutrient malabsorption and potential effects of parenteral nutrition (PN). Human growth hormone hGH has been shown in some studies to have anabolic effects on bone, but hGH effects on bone in patients with SBS are unknown. Methods: Adults with PN-dependent SBS underwent a 7-day period of baseline studies while receiving usual oral diet and PN and then began receiving modified diets designed to improve nutrient absorption and daily oral calcium/ vitamin D supplements (1500 mg elemental calcium and 600 IU vitamin D, respectively). Subjects were randomized to receive in a double-blind manner either subcutaneous (sc) saline placebo as the control or hGH (0.1 mg/kg/d for 3 weeks, then 0.1 mg/kg 3 days a week for 8 subsequent weeks). Open-label hGH was given from week 13 to week 24 in subjects who required PN after completion of the 12-week double-blind phase. Markers of turnover (serum osteocalcin and urinary N-telopeptide [NTX]), vitamin D nutriture (serum calcium, 25-hydroxyvitamin D [25-OH D] and parathyroid hormone [PTH] concentrations), and intestinal calcium absorption were measured at baseline and at weeks 4 and 12. Dual x-ray absorptiometry (DXA) of the hip and spine was performed to determine mineral density (BMD) at baseline and weeks 12 and 24.

The majority of subjects in each group exhibited evidence of vitamin D deficiency at baseline (25-OH D levels <30 ng/mL; 78% and 79% of control and HGH-treated subjects, respectively). Subjects treated with hGH demonstrated a significant increase from baseline in serum osteocalcin levels at 12 weeks (+62%; p < .05). The levels of NTX were increased over time in the HGH-treated group; however, this did not reach statistical significance. Both NTX and osteocalcin remained unchanged in control subjects. BMD of the spine and total hip was unchanged in subjects treated with placebo or HGH at 24 weeks. However, femoral neck BMD was slightly but significantly decreased in the placebo group at this time point but remained unchanged from baseline in the HGH-treated subjects. Conclusions: HGH therapy significantly increased markers of bone turnover during the initial 3 months of therapy and stabilized femoral neck bone mass over a 6-month period in patients with severe SBS undergoing intestinal rehabilitation.

HGH Bone Skeleton Calcium and Mineral Structure

The Benefits of growth hormone treatment on bone metabolism, bone density and bone strength in growth hormone deficiency and osteoporosis. Department of Internal Medicine I-Endocrinology and Metabolism, University Medical Clinic Heidelberg , Germany .Bone mass is reduced in patients with Growth Hormone deficiency (GHD) leading to an increased vertebral fracture rate and clinically significant osteoporosis. Patients with GHD of juvenile onset have reduced skeletal mineralization. When substituting GH in patients with GHD, bone turnover is increased and bone mineral density initially decreases during the first year due to the increase in remodelling space. From the experience in patients with acromegaly, cortical bone mass is increased and trabecular bone mass is normal in eugonadal or decreased in the hypogonadal patients. However, bone mineral content and bone area are increased leading to a higher biomechanical competence of bone as shown in rats. In patients with GHD of juvenile onset, mineralization and bone maturation are achieved during treatment with GH in adult life after having reached final body height leading to an increase in bone mass. The GH/ IGF-I system is dysregulated in patients with post-menopausal osteoporosis. This is shown by reduced systemic IGF and IGFBP-3-levels in osteoporosis suggesting a decrease of endogenous GH-secretion or a dysregulation of the GH receptor system which is beyond the normal ageing process of the GH/IGF system, the “somatopause”. A premature somatopause may be responsible for the dysregulation in some patients with osteoporosis. However, 24-h GH profiles do not differ between patients suffering from osteoporosis or osteoarthritis. Treatment of osteoporosis with GH might be beneficial due to the increased bone metabolism and improved bone geometry which occurs with GH. The substantial increase of bone remodeling achieved with GH may be helpful during late post-menopause with decreased bone turnover and impaired osteoblastic function. Using GH to prevent physiological bone loss that occurs with age seems possible, but has to be discussed on an ethical and economic basis. Article provided by National Library of Medicine