Predictors of Treatment Response to Tesamorelin, a Growth Hormone-Releasing Factor Analog, in HIV-Infected Patients with Excess Abdominal Fat

Effect of tesamorelin in people with HIV with and without dorsocervical fat: Post hoc analysis of phase III double-blind placebo-controlled trial

Tesamorelin, a synthetic growth hormone-releasing hormone, is indicated for the reduction of visceral adipose tissue (VAT) in people with HIV. Here, we performed a post hoc analysis of participants receiving tesamorelin for 26 weeks in a phase III clinical trial. Efficacy data were compared between individuals with and without dorsocervical fat, stratified by tesamorelin response. Among tesamorelin responders, VAT and waist circumference (WC) decreased in both dorsocervical fat groups and did not statistically differ (VAT P = 0.657, WC P = 0.093). These data demonstrate that tesamorelin is equally effective and should be considered in the treatment of excess VAT regardless of the presence of dorsocervical fat.

Pituitary growth hormone (GH) secretion is partially rescued in HIV-infected patients with GH deficiency (GHD) compared to hypopituitary patients

Biochemical growth hormone deficiency is prevalent among human immunodeficiency virus-infected patients, but if this condition is clinically relevant remains challenging. The aim is to prospectively compare the growth hormone deficiency/insulin-like growth factor-1 status of 71 human immunodeficiency virus-infected patients with impaired growth hormone response to growth hormone releasing hormone + Arginine with that of 65 hypopituitary patients affected by a true growth hormone deficiency secondary to pituitary disease. The main outcomes were: basal serum growth hormone, insulin-like growth factor-1, insulin-like growth factor binding protein 3, growth hormone peak and area under the curve after growth hormone response to growth hormone releasing hormone + Arginine test, body mass index, waist and hip circumference, and body composition by dual energy X-ray absorptiometry. Insulin-like growth factor-1 binding protein 3, basal growth hormone (p < 0.005), growth hormone peak and area under the curve after growth hormone response to growth hormone releasing hormone + Arginine, waist to hip ratio, insulin-like growth factor-1, fasting glucose, insulin, and triglycerides (p < 0.0001) were lower in hypopituitary than human immunodeficiency virus-infected patients. Total and trunk fat mass by dual energy X-ray absorptiometry were higher in hypopituitary than in human immunodeficiency virus-infected patients (p < 0.0001). In all the patients total body fat was associated with both growth hormone peak and area under the curve at stepwise linear regression analysis. The degree of growth hormone deficiency is more severe in hypopituitary than in human immunodeficiency virus-infected patients, suggesting that the function of growth hormone/insulin-like growth factor-1 axis is partially rescued in the latter thanks to a preserved pituitary secretory reserve. Data from the current study suggest that human immunodeficiency virus-infected patients with peak growth hormone < 9 mg/L may have partial growth hormone deficiency and clinicians should be cautious before prescribing recombinant human growth hormone replacement treatment to patients living with human immunodeficiency virus.

Non-alcoholic fatty liver disease and non-alcoholic steatohepatitis in patients with HIV

Liver disease is a leading cause of morbidity and mortality among people with HIV, and in this era of safer and more effective hepatitis C therapy, non-alcoholic fatty liver disease (NAFLD) could soon emerge as the most common liver disease in this population. NAFLD is common among patients with HIV, and might be more likely to progress to non-alcoholic steatohepatitis (NASH) and NAFLD-related fibrosis or cirrhosis in these patients than in individuals without HIV. Several mechanisms of NAFLD pathogenesis are postulated to explain the disease severity in patients with HIV; these mechanisms include the influence of the gut microbiome, and also metabolic, genetic, and immunological factors. Although treatment strategies are currently based on modification of NAFLD risk factors, many new drugs are now in clinical trials, including trials specifically in patients with HIV. Thus, the identification and risk-stratification of patients with HIV and NAFLD are becoming increasingly important for accurately counselling of these patients regarding their prognosis and for establishing the most appropriate disease-altering therapy.

Growth hormone deficiency and human immunodeficiency virus

Treatment with highly active antiretroviral drugs (HAART) is associated with several endocrine and metabolic comorbidities. Pituitary growth hormone (GH) secretion seems to be altered in human immunodeficiency virus (HIV) infection, and about one-third of patients have biochemical GH deficiency (GHD). We undertake a historical review of the functioning of the GH/insulin-like growth factor-1 (IGF-1) axis in patients with acquired immunodeficiency syndrome, and provide an overview of the main changes of the GH/IGF-1 axis occurring today in patients with HIV. Both spontaneous GH secretion and GH response to provocative stimuli are reduced in patients with HIV infection, especially in those with HIV-related lipodystrophy. The role of fat accumulation on flattened GH secretion is discussed, together with all factors able to potentially interfere with the pituitary secretion of GH. Several factors contribute to the development of GHD, but the pathophysiologic mechanisms involved in the genesis of GHD are complex and not yet fully elucidated owing to the difficulty in separating the effects of HIV infection from those of HAART, comorbidities and body changes. An update on the putative mechanisms involved in the pathogenesis of altered GH secretion in these patients is provided, together with an overview on the therapeutic strategies targeting the GH/IGF-1 axis to counteract fat redistribution associated with HIV-related lipodystrophy. The clinical significance of GHD in the context of HIV infection is discussed. The administration of tesamorelin, a GH releasing hormone analogue, is effective in reducing visceral fat in HIV-infected patients with lipodystrophy. This treatment is promising and safer than treatment with high doses of recombinant human growth hormone, which has several side-effects.

Visceral fat is associated with brain structure independent of human immunodeficiency virus infection status

The combined effects of human immunodeficiency virus (HIV), obesity, and elevated visceral adipose tissue (VAT) on brain structure are unknown. In a cross-sectional analysis of Multicenter AIDS Cohort Study (MACS) participants, we determined associations between HIV serostatus, adiposity, and brain structure. Men (133 HIV+, 84 HIV-) in the MACS Cardiovascular 2 and magnetic resonance imaging (MRI) sub-studies with CT-quantified VAT and whole brain MRI measured within 1 year were assessed. Voxel-based morphometry analyzed brain volumes. Men were stratified by elevated (eVAT, ≥100cm²) or "normal" (nVAT, <100cm²) VAT. Forward stepwise modeling determined associations between clinical and demographic variables and regional brain volumes. eVAT was present in 67% of men. Groups were similar in age and education, but eVAT men were more likely to be HIV+ and have hypertension, diabetes mellitus, body mass index >25 kg/m², smaller gray and white matter volumes, and larger cerebrospinal fluid volume than nVAT men. In multivariate analysis, hypertension, higher adiponectin, higher interleukin-6, age, diabetes mellitus, higher body mass index, and eVAT were associated with brain atrophy (p < 0.05, ordered by increasing strength of association), but HIV serostatus and related factors were generally not. No interactions were observed. Greater VAT was associated with smaller bilateral posterior hippocampus and left mesial temporal lobe and temporal stem white matter volume. Traditional risk factors are more strongly associated with brain atrophy than HIV serostatus, with VAT having the strongest association. However, HIV+ MACS men had disproportionately greater VAT, suggesting the risk for central nervous system effects may be amplified in this population.