Bone mineral content in patients with congenital generalized lipodystrophy is unaffected by metreleptin replacement
John D Christensen1, Andreea O Lungu, Elaine Cochran
1Diabetes, Endocrinology, and Obesity Branch, National Institute of Diabetes and Digestive and Kidney Diseases (J.D.C., E.C., P.G., K.I.R., R.J.B.), National Institute of Dental and Craniofacial Research (M.T.C., R.I.G.), Nuclear Medicine Department, Clinical Center (J.C.R.), National Institutes of Health, Bethesda, Maryland 20892; and Joslin Diabetes Center (A.O.L.), Brookline, Massachusetts 02215.
Context:
Leptin alters bone and mineral metabolism in rodents, but this has not been verified in humans. PATIENTS with congenital generalized lipodystrophy (CGL) have low leptin due to deficient adipose mass and serve as models of leptin deficiency and replacement.
Objective:
To study the effects of recombinant human methionyl leptin (metreleptin) on bone mineral content (BMC) and mineral metabolism.
Design And Setting:
An open-label nonrandomized study at the National Institutes of Health.
Patients:
Thirty-one patients with CGL (ages 4.3 to 46.7 y).
Intervention:
Metreleptin (0.06 to 0.24 mg/kg/d) for 6 months to 11 years.
Outcome Measures:
BMC was assessed by dual-energy x-ray absorptiometry. SD scores (SDS) for BMC were calculated based on height, race, sex, and age using population normative data. Calcium, phosphorus, PTH, 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D were measured at baseline and follow-up.
Results:
At baseline, patients demonstrated significantly increased total body less head BMC (mean SDS, 1.8 ± 0.7), height (mean SDS, 1.3 ± 1.3), and lean mass index, defined as lean body mass per height squared (mean SDS, 1.5 ± 0.83), vs population normative data. No change in total body less head BMC was observed after metreleptin. Lean mass index decreased with metreleptin. Serum calcium decreased with metreleptin, but remained within normal limits. No changes were seen in phosphorus, PTH, or vitamin D.
Conclusions:
In contrast to rodent models, CGL patients have increased BMC in the leptin-deficient state, which does not change with leptin replacement. The high BMC in these patients is partially explained by high lean mass and tall stature.
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