Impact of elevated homocysteine levels on vision u...( Homocysteine an amino acid believed ...),Health

Homocysteine, an amino acid believed to contribute to heart attack, stroke and dementia, likely also is a player in retinal damage and vision loss, researchers say.

Homocysteine levels rise when folic acid levels drop, a common problem for Americans whose diets are often poor in folate-rich fruits, tomatoes, vegetables and grains, according to Dr. Sylvia Smith, cell biologist at the Medical College of Georgia.

Scientists want to know the impact of resulting elevated homocysteine levels on the extensive blood vessel and neuronal network of the retina; their preliminary evidence suggests that it isnt good.

You dont have to be a cell biologist to see that there is a problem in this retina. Its terribly disrupted, Dr. Smith says, looking at images of a fragmented 10-layer retina exposed to high levels of homocysteine. A healthy retina tissue at the back of the eye that receives light and transforms it to a neural impulse that goes to the brain is beautifully organized, horizontally and vertically, she says.

What is the consequence of slightly elevated homocysteine on the retina, on its architecture, its functioning, its ability to withstand stress? Dr. Smith hopes to find the answers with a $1.8 million grant from the National Institutes of Health.

She and Dr. Vadivel Ganapathy, chair of the MCG Department of Biochemistry and Molecular Biology, have been studying how folate gets to the retina and how diseases such as diabetes interfere. They found it hard to ignore homocysteine as they studied folate, a vitamin essential to life.

Folate and vitamin B12 which Americans typically get plenty of convert homocysteine to methionine, an amino acid essential to protein synthesis.

Without the conversion, rising homocysteine levels interfere with the folding and structure of collagen, a component of bone, tissue and the basement membrane of blood vessel walls. When pregnant women dont get enough folate,
'/>"/>