Alessandro Di Rocco, MD Comments On the Future of HIV/AIDS Research
Alessandro Di Rocco, MD: Associate Professor of Neurology, Albert Einstein College of Medicine and Beth Israel Medical Center
Neurologic problems remain common in the course of HIV infection, although the introduction of HAART has greatly diminished the frequency and severity of these complications.
Dementia is now much less frequent even in individuals with severe immunodeficiency. The use of AZT first and then of the other antiretroviral medications has diminished the virus load within the brain, limiting the direct infection of brain cells and the indirect toxic effect of viral particles or abnormal immune response that can lead to brain damage. Although the mechanism causing brain cell death is still unknown, it is known that the higher the viral load inside the brain, the more likely an individual is to develop dementia. Most of the drugs currently used, however, have only limited access to the brain. Current research is trying to identify new antiretrovirals that have high efficacy in the brain. Additional research is aimed at understanding how the virus leads to nerve cell damage and at developing treatment that would prevent and stop the premature death of brain cells. Clinical trials will start in the next few months to test the safety and the efficacy of these new drugs.
Neuropathy is another common complication of HIV infection. While neuropathy can be the direct result of HIV infection, it may also be due to some of the antiretroviral drugs, in particular d4T (Zerit), ddI (Videx) and ddC (Hivid). These drugs may, however, be necessary to suppress the viral load and may ultimately help to diminish the rate of neurological complications. Currently there is only treatment for the symptoms of the neuropathy with a number of medications that diminish the burning sensation at the bottom of the feet. There is, however, no therapy that can eliminate the damage to the nerves and cure the neuropathy. A large study with Nerve Growth factor (NGF), a chemical that in laboratory promotes the growth of nerve endings, did not lead to any significant benefit. Current research is looking at whether mitochondria, the particles that produce energy within the nerve cells, are responsible for the neuropathy and at developing new treatments that would cause the re-growth of nerve endings.
Myelopathy is a spinal cord disease that is rather common in HIV infection. As myelopathy progresses very slowly, it is often misdiagnosed or ignored. The symptoms are urgency to urinate, frequent urination, weakness in the legs (often evident when climbing stairs), leg stiffness and sexual dysfunction in men. Myelopathy is not due to viral infection of the spinal cord, but to a metabolic dysfunction induced by the virus that leads to the detachment of the protecting layering (myelin) from the nervous fibers. Current research is trying to determine how the virus causes the metabolic abnormality. Supplementation with the natural amino acid L-methionine has been reported to improve the myelopathy, and this treatment is currently being tested in a larger study. Other therapies are also being studied that could prevent and, possibly, cure the myelopathy.
Neurologic opportunistic infections such as cryptoccocal meningitis, CMV, toxoplasmosis, PML (Progressive Multifocal Leukoencephalopathy) and tumors like lymphoma have become rarer, and better treatment has been developed to treat them.
This article was provided by AIDS Community Research Initiative of America. It is a part of the publication CRIA Update. Visit ACRIA's website to find out more about their activities, publications and services.