Hypopituitarism and HIV-infection: a new comorbidity in the HAART era?

Several comorbidities are associated with the HIV infection and may involve also the endocrine-metabolic system. Consistently, the recent development of the therapeutic regimen highly active antiretroviral therapy (HAART) ruled out a significant improvement both in the prognosis and life expectancy of HIV-infected patients, but disclosed also new serious drug-related toxicity. Of these, the lipodystrophy syndrome is the most frequent, occurring in up to 83% of HIV-infected patients under HAART. The HIV-related lipodystrophy is associated with alterations in GH dynamics, affecting both basal and stimulated GH secretion. This GHIGF- I secretive pattern resembles that of severe GH deficiency in adulthood due to pituitary diseases, but without leading to IGF-I serum levels below the normal range. The impairment of pituitary GH secretion has been ascribed to the hormonal and metabolic inhibitory effect due to adipose tissue redistribution in HIV-infected males, since in these patients pituitary GH secretion appeared to be inversely related to visceral adipose tissue accumulation and waist to-hip-ratio. However, whether these patients suffer from a true GH deficiency due to an intrinsic pituitary failure or display only a functional reduction of GH secretion due to visceral adiposity remains still a matter of debate, especially in HIV-infected females.