3D DXA Hip Differences in Patients with Acromegaly or Adult Growth Hormone Deficiency

The skeleton is regulated by and responds to pituitary hormones, especially when the circulating levels are perturbed in disease. This study aims to analyse the between-group differences in 3D dual-energy X-ray absorptiometry (DXA) parameters at the hip site among patients with acromegaly or adult growth hormone deficiency (AGHD) and a healthy control group. The current cross-sectional study includes data for 67 adults, 20 with acromegaly, 14 with AGHD and 33 healthy controls. We obtained the areal bone mineral density (aBMD) outcomes using DXA and cortical and trabecular parameters using 3D-DXA software (3D-SHAPER). The mean-adjusted 3D-DXA parameters did not differ between acromegaly patients and the controls (p > 0.05); however, we found cortical bone impairment (−7.3% to −8.4%; effect size (ES) = 0.78) in AGHD patients (p < 0.05). Differences in the cortical bone parameters were more evident when comparing AGHD patients (−8.5% to −16.2%; ES = 1.22 to 1.24) with acromegaly patients (p < 0.05). In brief, the 3D mapping highlighted the trochanter as the site with greater cortical bone differences between acromegaly patients and the controls. Overall, AGHD patients displayed lower cortical parameters at the trochanter, femoral neck and intertrochanter compared to the controls and acromegaly patients. To sum up, 3D-DXA provided useful information about the characteristics of bone involvement in growth hormone (GH)-related disorders. Patients with AGHD showed distinct involvement of the cortical structure.

High Irisin levels in nondiabetic HIV-infected males are associated with insulin resistance, nonalcoholic fatty liver disease, and subclinical atherosclerosis

OBJECTIVE

HIV infection is associated with an increased risk of cardiovascular disease. Irisin is a miokyne secreted by skeletal muscle, which may influence insulin homeostasis, nonalcoholic fatty liver disease (NAFLD) and atherosclerosis. Our objective was to evaluate the relationships between serum irisin, insulin homeostasis, NAFLD and subclinical atherosclerosis in HIV-infected males.

DESIGN

Cross-sectional study in a cohort of HIV-infected patients.

PATIENTS

Inclusion criteria: men older than 18 years; antiretroviral therapy (ART) -naïve or on effective ART (<50 HIV-1 RNA copies/mL) without changes in the previous 6 months; no diabetes or hepatitis C.

MEASUREMENTS

Irisin was measured by enzymatic immunoassay (Phoenix Pharmaceuticals), insulin sensitivity by homeostasis model assessment of insulin resistance (HOMA-IR), as well as the 2-hour continuous infusion of glucose with model assessment (CIGMA-HOMA). Hepatic steatosis was measured by 1-H magnetic resonance spectroscopy, subclinical atherosclerosis by evaluation of carotid intima-media thickness (C-IMT), measured by Ultrasonography.

RESULTS

Eight nine men (age 42.0 ± 8.3 years, duration of HIV infection 7.9 ± 5.6 years, CD4 count 547 ± 279 cells/mL) were included. Circulating irisin was positively related to HOMA-IR and CIGMA-HOMA, hepatic triglyceride content, and to VAT/SAT ratio. Higher irisin concentrations were associated with higher C-IMT, although this association did not persist in multivariate analysis. Lipodystrophy and a higher baseline PAI-1 concentration were independently associated with C-IMT.

CONCLUSIONS

In male HIV patients without diabetes, higher irisin concentrations are positively associated with insulin resistance, NAFLD and subclinical atherosclerosis. However, waist-hip-ratio is the main determinant of insulin resistance, and PAI-1 and lipodystrophy were the strongest determinants of IMT in this population.