HIV-associated lipodystrophy syndrome occurs in individuals treated with antiretroviral drugs (usually a protease inhibitor), and is characterized by cosmetically disfiguring lipohypertrophy in the dorsocervical fat pad (buffalo hump), circumferentially around the neck, the breasts, and the abdomen (central adiposity), and lipoatrophy of the cheeks and proximal extremities (peripheral wasting); some cases are associated with increase in serum triglyceride and glucose levels.
Causes of HIV Associated Lipodystrophy Syndrome
Unknown, but protease inhibitors may inhibit proteins involved in lipid metabolism, with the primary event being apoptosis and reduced differentiation of peripheral adipocytes. HIV protease has 60% homology with two human regulatory proteins that affect lipid metabolism, i.e., the cytoplasmic retinoic-acid binding protein type I (CRABP-1) and the low-density lipoprotein-receptor-related protein (LPR). Inhibition not only of HIV protease but also of CRABP-1 would impair the metabolism of retinoic acid, leading to fat-cell death and consequent lipid release and/or reduced lipid storage. Inhibition of LPR may result in the failure to remove fatty acids from circulating triglycerides into the vascular endothelium and in a reduced hepatic uptake of chylomicrons.
Symptoms of HIV Associated Lipodystrophy Syndrome
Signs of HIV-LS are a wasting, or a reduction in fat (lipoatrophy), in the face, arms, legs and buttocks; and an increase in fat (lipodystrophy) in the abdomen, back of the neck and breasts. The added abdominal fat is primarily visceral fat, which accumulates within the abdominal cavity, around the organs.
Diagnosis
Dual energy X-ray absorptiometry (DEXA) scan for quantifying muscle, bone and fat in arms, legs and abdomen, and computed tomography (CT) or MRI to quantify and discriminate between visceral and subcutaneous fat.
Treatment
For most individuals with mild to moderate lipodystrophy, the changes in body habitus are not significant. However, with more severe involvement, patients may request change in protease-inhibitor therapy in spite of excellent response of HIV disease.
Lipohypertrophy Discontinuing and/or changing antiretroviral drugs may result in regression. Administration of recombinant human growth factor. Liposuction has been helpful in some cases, but recurrence is common.
Lipoatrophy For the cheeks, lipotransfer with a syringe may be effective. Implantation of Gore-Tex.
References