Circadian growth hormone secretion in asymptomatic human immune deficiency virus infection and acquired immunodeficiency syndrome

Human Immunodeficiency Virus Infection and the Endocrine System

In the current era of effective antiretroviral therapies (ARTs), human immunodeficiency virus (HIV) infection became a chronic disorder that requires long term follow-up. Among other medical issues, these patients may develop endocrine problems, specific to HIV infection and its treatment. The purpose of this review is to give an overview of common endocrine complications associated with HIV infection, and to propose diagnostic and therapeutic strategies. HIV can affect the endocrine system at several levels. Adrenal and gonadal dysfunction, osteoporosis with increased fracture risk, dyslipidemia with increased cardiovascular risk, are some of the endocrine disorders prevalent in HIV-infected patients that may negatively influence quality of life, and increase morbidity and mortality. While ARTs have dramatically increased life expectancy in the HIV-infected population, they are not devoid of adverse effects, including endocrine dysfunction. Physicians caring for HIV-infected patients should be knowledgeable and exercise a high index of suspicion for the diagnosis of endocrine abnormalities, and in particular be aware of those that can be life threatening. Endocrine evaluation should follow the same strategies as in the general population, including prevention, early detection, and treatment.

Adrenal Insufficiency: A Forgotten Diagnosis in HIV/AIDS Patients in Developing Countries

Adrenal insufficiency (AI) is one of the most common endocrine disease in patients with HIV/AIDS, leading to high morbidity and mortality in HIV patients who become critically ill. Various etiologies are associated with the condition, including cytomegalovirus (CMV), Mycobacterium tuberculosis, lymphoma, Kaposi's sarcoma, and drugs such as rifampin, among others. HIV patients with advanced disease develop relative cortisol deficiency largely due to the reduction of cortisol reserve, which predisposes patients to adrenal crisis in periods of stress or critical illness. The prevalence of AI in HIV/AIDS patients during HAART era is higher in developing than developed countries, probably due to limited access to both diagnosis and adequate treatments which increases the risk of opportunistic infections. The clinical features of functional adrenal insufficiency in HIV/AIDS patients can be masked by various infectious, noninfectious, and iatrogenic causes, which reduce clinical recognition of the condition. Development of simple screening algorithms may help clinicians reach the diagnosis when approaching these patients. In many low-income countries, most HIV patients are diagnosed with advanced disease; thus, further research is necessary to elucidate the prevalence of adrenal insufficiency in HIV/AIDS patients and the condition's impact on mortality in this population.

Insulin-Like Growth Factor Is Associated with Changes in Body Composition with Antiretroviral Therapy Initiation

Growth hormone (GH)/insulin-like growth factor (IGF)-1 axis abnormalities have been associated with body composition changes among HIV-infected persons with wasting or lipodystrophy. Little is known of GH/IGF-1 axis alterations with antiretroviral therapy (ART) initiation or differing ART therapies. The AIDS Clinical Trials Group Prospective Evaluation of Antiretrovirals in Resource-Limited Settings (PEARLS) study was a prospective, randomized clinical trial of ART initiation with emtricitabine/tenofovir + efavirenz (FTC/TDF+EFV) versus lamivudine/zidovudine + efavirenz (3TC/ZDV+EFV) in HIV-1-infected individuals from resource-diverse settings. IGF-1 was measured from baseline, week 48, and week 96 stored serum samples. Multivariate models were constructed. 415 participants were included: 170 (41%) were randomized to FTC/TDF+EFV and 245 (59%) to 3TC/ZDV+EFV. The mean age was 35 years, 60% were black, 42% women. The mean IGF-1 level did not change significantly from baseline to week 96 (-0.65 ng/ml; 95% confidence interval (CI) -5.18-3.87), p = .78 and there were no differences by treatment arm at week 96, p = .74. Lower baseline IGF-1 was associated with age, non-white race, greater waist-hip ratio (WHR), low CD4 count, and lower baseline albumin (all p < .01) but not plasma HIV-1 RNA, body mass index, or treatment arm. Greater change in IGF-1 from baseline to 96 weeks was associated with female sex, smaller WHR change, lower baseline albumin, and higher baseline HIV-1 RNA (all p < .01). ART initiation with either ZDV or TDF did not significantly impact overall IGF-1 levels. Baseline and on-treatment changes in IGF-1 with ART initiation may be related to the body composition changes that occur after ART initiation.

HIV gp120 inhibits the somatotropic axis: a possible GH-releasing hormone receptor mechanism for the pathogenesis of AIDS wasting

AIDS is often associated with growth retardation in children and wasting in adults. The dissociated envelope protein of the HIV (HIV-1), gp120, can be found in significant concentrations in the parenchyma and cerebrospinal fluid of brains in infected individuals, even in the earliest stages of HIV-1 disease. On the basis of this and the fact that we observed pentapeptide sequence homology between GH-releasing hormone (GHRH) and the V2 receptor-binding region of gp120, we initiated experiments to determine whether gp120 could affect GH secretion and growth in vivo and/or interact with anterior pituitary GHRH receptors in vitro. Although acute IV administration of gp120 in conscious rats had no effect on plasma GH levels, acute administration of gp120 (400 ng) into the brain significantly suppressed pulsatile GH release over a 6-h period compared with saline-injected controls. Furthermore, the putative gp120 antagonist, Peptide T (DAPTA), prevented the suppression of GH by gp120. In support of these in vivo findings, gp120 also significantly (P < 0.05) suppressed GHRH-stimulated GH release in static cultures of dispersed pituitary cells and from cells undergoing perifusion with the peptides. DAPTA prevented the GH suppression by gp120 in both of the pituitary cell paradigms. Furthermore, chronic administration of gp120 into the third ventricle significantly reduced body weight in juvenile rats, compared with saline-injected controls. Thus, gp120 appears to act both at the hypothalamus and pituitary to suppress GH release, and its action at these two locations is associated with a significant loss in body weight in chronically treated young animals. These findings may suggest a specific mechanism for the pathogenesis of wasting in HIV-1 patients that involves blockade of endogenous GHRH receptors by gp120.

Low IGF-I levels are often uncoupled with elevated GH levels in catabolic conditions

Increased GH together with decreased IGF-I levels pointing to peripheral GH insensitivity in critically ill patients have been reported by some but not by other authors. To clarify whether elevated GH levels are coupled with low IGF-I levels in all catabolic conditions, basal GH and IGF-I levels were evaluated in patients with sepsis (SEP, no.=13; age [mean+/-SE]=59.2+/-1.2 yr), trauma (TRA, no.=16; age=42.3+/-3.4 yr), major burn (BUR, no.=26; age=52.8+/-4.2 yr) and post-surgical patients (SUR, no.=11; age=55.0+/-4.7 yr) 72 hours after ICU admission or after cardiac surgery. GH and IGF-I levels were also evaluated in normal subjects (NS, no.=75; age=44.0+/-1.5 yr), in adult hypopituitaric patients with severe GH deficiency (GHD, no.=54; age=44.8+/-2.3 yr), in patients with liver cirrhosis (LC, no.=12; age=50.4+/-2.8 yr) and in patients with anorexia nervosa (AN, no.=19; age=18.7+/-0.8 yr). Basal IGF-I and GH levels in GHD were lower than in NS (68.6+/-6.4 vs 200.9+/-8.7 microg/l and 0.3+/-0.1 vs 1.4+/-0.2 microg/l; p<0.01). On the other hand, AN and LC showed IGF-I levels (70.4+/-9.1 and 52.4+/-10.5 microg/l) similar to those in GHD while GH levels (10.0+/-2.8 and 7.9+/-2.1 microg/l) were higher than those in NS (p<0.01). IGF-I levels in SEP (84.5+/-8.8 microg/l) were similar to those in GHD, AN and LC and lower than those in NS (p<0.01). IGF-I levels in BUR (105.2+/-10.9 microg/l) were lower than in NS (p<0.01) but higher than those in GHD, AN, LC and SEP (p<0.01). On the other hand, in TRA (162.8+/-17.4 microg/l) and SUR (135.0+/-20.7 microg/l) IGF-I levels were lower but not significantly different from those in NS and clearly higher than those in GHD, AN, LC, SEP and BUR. Basal GH levels in SEP (0.6+/-0.2 microg/l), TRA (1.8+/-0.5 microg/l), SUR (2.2+/-0.5 microg/l) and BUR (2.2+/-0.5 microg/l) were similar to those in NS, higher (p<0.05) than those in GHD and lower (p<0.01) than those in AN and LC. In conclusion, our data demonstrate that low IGF-I levels are not always coupled with elevated GH levels in all catabolic conditions. Differently from cirrhotic and anorectic patients, in burned and septic patients GH levels are not elevated in spite of very low IGF-I levels similar to those in panhypopituitaric GHD patients. These findings suggest that in some catabolic conditions peripheral GH insensitivity and somatotrope insufficiency could be concomitantly present.