The retinal pigment epithelium (the edges of cells in red) treated with HIV / AIDS drugs are seen in a photo in an undated statement courtesy of Younghee Kim of the University of Kentucky.
(Reuters) - A group of drugs used for three decades by people infected with the virus that causes AIDS can be effective in treating the leading cause of blindness among the elderly.
HIV drugs called nucleotide reverse transcriptase inhibitors (NRTIs), including AZT and three others, blocked age-related macular degeneration in mice and worked well in experiments involving human retinal cells in the laboratory, the researchers said on Tuesday.
In people infected with HIV, NRTIs block an enzyme that the virus uses to create more copies of itself. The new research shows that the drugs also block the activity of a biological pathway responsible for activating inflammatory processes in the body.
It is that previously unrecognized quality that makes NRTIs a promise in the treatment for macular degeneration as well as graft versus host disease, a rarer disease that can occur after a bone marrow or stem cell transplant, say the researchers.
The University of Kentucky ophthalmologist, Dr. Jayakrishna Ambati, who led the study published in the journal Science, said that macular degeneration affects approximately 50 million people worldwide.
"As the population ages, it is projected to affect 200 million people by the year 2020. It is therefore critical that we develop new and improved treatments for this disease that is growing as an epidemic," said Ambati.
Macular degeneration causes the death of cells in the macula, a part of the eye located near the center of the retina that allows for viewing in pleasant detail.
Chronic disease has two forms: "dry" and "wet". There are several treatments for “wet” macular degeneration, but only about a third of patients achieve improvements significant in vision. There are no approved treatments for the “dry” form that is much more common, but less severe.
The "wet" type occurs when abnormal blood vessels grow under the macula and leak blood and fluid. The "dry" form occurs when the cells in the macula break.
In the new study, NRTIs blocked a powerful collection of proteins that can kill cells in the retina, preserving vision in mice.
The researchers are planning clinical trials for the next few months and this could be known within approximately two or three years if the drugs are effective in treating macular degeneration in people, Ambati said.
Since these inexpensive drugs are already approved by the US Food and Drug Administration and have a good safety record, they could quickly be "reproposed" to treat other illnesses, he added.
CREDITS: REUTERS / YOUNGHEE KIM / KENTUCKY UNIVERSITY / REUTERS COMMUNICATION
(Reporting by Will Dunham; Editing by Frances Kerry)
Portuguese translation:Rodrigo Pellegrini Sgobbi
Reissue and illustration Cláudio Souza