Increased adipocyte apoptosis in lipoatrophy improves within 48 weeks of switching patient therapy from stavudine to abacavir or zidovudine

Objectives: Lipoatrophy is an important manifestation of the lipodystrophy syndrome and is particularly associated with stavudine exposure. Increased apoptosis has been suggested as a possible mechanism of lipoatrophy. We assessed the degree and reversibility of adipocyte apoptosis in patients with lipoatrophy before and 48 weeks after substituting abacavir or zidovudine for stavudine. Methods: Apoptotic adipocytes were identified using terminal transferase dUTP nick end labeling and quantified using video image analysis. Results: Fat biopsy specimens were obtained from patients before (n = 15) and 48 weeks after (n = 10) switching from stavudine and from 20 HIV-uninfected controls. More apoptotic cells were seen in fat samples from patients with lipoatrophy treated with stavudine than in specimens from controls (P < 0.0001). Forty-eight weeks after switching from stavudine to abacavir or zidovudine, there was a reduction in apoptotic cells per unit area (P = 0.01) and as a proportion of all adipocytes present (P = 0.02) in patient biopsy specimens. Levels of adipocyte apoptosis in the 48-week biopsy specimens were no longer significantly different from those seen in control biopsy specimens (P > 0.1). Conclusions: Increased apoptosis is present in fat samples from patients with lipoatrophy treated with stavudine. This improves toward normal within 48 weeks of switching from stavudine to abacavir or zidovudine, suggesting a causative role for stavudine in this process.