Brain injury caused by HIV protease inhibitors: role of lipodystrophy and insulin resistance.

HIV-associated neurocognitive disorders (HAND) remain prevalent even with widespread use of combination antiretroviral therapy (ART), suggesting a potential role for co-morbidities in neurologic decline. Indeed, it is well established that ART drugs, particularly HIV protease inhibitors, can induce hyperlipidemia, lipodystrophy, and insulin resistance; all of which are associated with neurologic impairment. This study was designed to determine how metabolic dysfunction might contribute to cognitive impairment and to reveal specific metabolic co-morbidities that could be targeted to preserve brain function. Adult male C57BL/6 mice were thus treated with clinically relevant doses of lopinavir/ritonavir for 4 weeks, and subjected to thorough metabolic, neurobehavioral, and biochemical analyses. Data show that lopinavir/ritonavir resulted in manifestations of lipodystrophy, insulin resistance, and hyperlipidemia. Evaluation of neurologic function revealed cognitive impairment and increased learned helplessness, but not motor impairment following treatment with lopinavir/ritonavir. Further analyses revealed a significant linear relationship between cognitive performance and specific markers of lipodystrophy and insulin resistance. Finally, analysis of brain injury indicated that lopinavir/ritonavir treatment resulted in cerebrovascular injury associated with decreased synaptic markers and increased inflammation, and that the cerebral cortex was more vulnerable than the cerebellum or hippocampus. Collectively, these data reveal an intimate link between metabolic co-morbidities and cognitive impairment, and suggest that remediation of selective aspects of metabolic syndrome could potentially reduce the prevalence or severity HIV-associated neurocognitive disorders.