美研究发现中药黄芪对艾滋病病毒有抑制作用
November 10, 2008
Astragalus Extract May Strengthen Immune Response to HIV
When cells reproduce, their DNA gets capped at the ends by long repeated strands of genes called telomeres. Telomeres protect the genes, much like the plastic tips on the ends of shoelaces. Unfortunately, telomeres get shorter every time a cell reproduces, which ultimately causes the cells to become “exhausted” and to stop functioning properly. This occurs naturally as a person ages, but more rapidly in the HIV-fighting CD4 and CD8 cells of people with HIV.
One of the lead researchers in telomeres and HIV, Rita Effros, PhD, and her colleague Steven Russell Fauce, PhD, of the department of pathology at UCLA, had experimented with gene therapy as a way to keep telomeres from shortening. But ultimately the researchers turned to what could potentially be a much less expensive method: an extract from the medicinal plant astragalus.
According to Effros and Fauce, the extract, TAT2, keeps an enzyme called telomerase turned on. CD4s and CD8s can naturally produce telomerase, which helps keep telomeres from shortening, but only for so long. After a cell has divided too many times, the telomerase gene turns off.
In test tube experiments, Effros and Fauce exposed CD4 and CD8 cells collected from HIV-positive patients to TAT2. Not only did the substance slow the shortening of the cells’ telomeres, but it also increased the cells’ production of proteins known to inhibit HIV replication.
While studies of TAT2 have not yet been conducted in people, the authors believe the strategy “could be useful in treating HIV disease, as well as immunodeficiency and increased susceptibility to other viral infections associated with chronic diseases or aging.”
Search: Astragalus, TAT2, Rita Effros, Steven Russel Fauce, UCLA, telomeres, telomerase, DNA
Scroll down to comment on this story.
