Pouneh K Fazeli, Alexander T Faje, Miriam A Bredella, Sai Polineni, Stephen Russell, Megi Resulaj, Clifford J Rosen and Anne Klibanski
In anorexia nervosa, a psychiatric disease characterized by self-induced starvation and a model of chronic undernutrition, levels of subcutaneous (SAT) and visceral (VAT) adipose tissue are low, whereas marrow adipose tissue (MAT) levels are elevated compared to normal-weight women. The reason for this paradoxical elevation of an adipose tissue depot in starvation is not known. We sought to understand changes in MAT in response to subacute changes in weight and to compare these changes with those of other fat depots and body composition parameters.
Design and methods
We conducted a 12-month longitudinal study including 46 premenopausal women (n = 26 with anorexia nervosa and n = 20 normal-weight controls) with a mean (s.e.m.) age of 28.2 ± 0.8 years. We measured MAT, SAT, VAT and bone mineral density (BMD) at baseline and after 12 months.
At baseline, SAT (P < 0.0001), VAT (P < 0.02) and BMD of the spine and hip (P ≤ 0.0002) were significantly lower and vertebral and metaphyseal MAT (P ≤ 0.001) significantly higher in anorexia nervosa compared to controls. Weight gain over 12 months was associated with increases not only in SAT and VAT, but also epiphyseal MAT (P < 0.03). Changes in epiphyseal MAT were positively associated with changes in BMD (P < 0.03).
In contrast to the steady state, in which MAT levels are higher in anorexia nervosa and MAT and BMD are inversely associated, short-term weight gain is associated with increases in both MAT and BMD. These longitudinal data demonstrate the dynamic nature of this fat depot and provide further evidence of its possible role in mineral metabolism.
Paula P B Silva, Fatemeh G Amlashi, Elaine W Yu, Karen J Pulaski-Liebert, Anu V Gerweck, Pouneh K Fazeli, Elizabeth Lawson, Lisa B Nachtigall, Beverly M K Biller, Karen K Miller, Anne Klibanski, Mary Bouxsein and Nicholas A Tritos
Both acromegaly and adult growth hormone deficiency (GHD) are associated with increased fracture risk. Sufficient data are lacking regarding cortical bone microarchitecture and bone strength, as assessed by microfinite element analysis (µFEA).
To elucidate both cortical and trabecular bone microarchitecture and estimated bone strength in men with active acromegaly or GHD compared to healthy controls.
Design and subjects
Cross-sectional study at a clinical research center, including 48 men (16 with acromegaly, 16 with GHD and 16 healthy controls).
Areal bone mineral density (aBMD), cortical and trabecular bone microarchitecture and estimated bone strength (µFEA) at the radius and tibia.
aBMD was not different between the 3 groups at any skeletal site. At the radius, patients with acromegaly had greater cortical area (P < 0.0001), cortical thickness (P = 0.0038), cortical pore volume (P < 0.0001) and cortical porosity (P = 0.0008), but lower trabecular bone density (P = 0.0010) compared to controls. At the tibia, patients with acromegaly had lower trabecular bone density (P = 0.0082), but no differences in cortical bone microstructure. Compressive strength and failure load did not significantly differ between groups. These findings persisted after excluding patients with hypogonadism. Bone microarchitecture was not deficient in patients with GHD.
Both cortical and trabecular microarchitecture are altered in men with acromegaly. Our data indicate that GH excess is associated with distinct effects in cortical vs trabecular bone compartments. Our observations also affirm the limitations of aBMD testing in the evaluation of patients with acromegaly.