Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

AMD-Like Lesions Delayed in Mice Fed Lower Glycemic Index Diet

16.11.2011
Feeding older mice a lower glycemic index (GI) diet consisting of slowly-digested carbohydrates delays the onset of age-related, sight-threatening retinal lesions, according to a new study from the Laboratory for Nutrition and Vision Research at the Jean Mayer USDA Human Nutrition Research Center on Aging (USDA HNRCA) at Tufts University.

The researchers studied middle-aged and older mice that consumed either a higher or lower GI diet. Mice fed the lower GI diet developed fewer and less-severe age-related lesions in the retina than the mice fed the higher GI diet. The lesions included basal laminar deposits, which typically develop after age 60 in the human retina and are the earliest warning sign of Age-Related Macular Degeneration (AMD).

“To our knowledge, we have established the first mature, mammalian model indicating a delay in the development of AMD-like lesions as the result of a lower GI diet,” says Allen Taylor, PhD, director of the Laboratory for Nutrition and Vision Research at the USDA HNRCA. “The only difference between the two groups of mice we studied is the GI of their meals, which suggests that diet alone is enough to accelerate or delay the formation of lesions. These results, coupled with similar observations made by our laboratory in earlier human epidemiologic studies imply that lower GI diets hold potential as an early intervention for preventing onset and progress of AMD.”

The dietary glycemic index (DGI) measures the rate at which glucose is delivered to the bloodstream after consuming carbohydrates. Higher GI foods including white bread and white potatoes trigger a rapid delivery of glucose that pushes the body to work overtime to absorb, whereas lower GI foods, like whole grain bread and fruits and vegetables, initiate a slower release of glucose that is more easily processed by cells.

Compared to the mice on the lower GI diet, mice on the higher GI diet demonstrated elevated accumulations of debris known as advanced glycation end products (AGEs) in the whole retina, particularly in the cells of the RPE. The RPE plays a crucial role in maintaining vision and its dysfunction results in the gradual central vision loss that is the hallmark of AMD. AGE accumulation has also been linked to tissue damage in other age-related diseases such as Type 2 diabetes and cardiovascular disease.

“We presume the elevated accumulation of AGEs we saw in the retina of the higher GI group is associated with toxicity. The AGEs result from the modification of proteins by excess glucose and this compounds the normal protein damage that happens as we age,” says Karen Weikel, first author and a PhD candidate at the Friedman School of Nutrition Science and Policy at Tufts. “While previous research has linked higher GI diets to AGE accumulation in the blood, ours appears to be the first to show diet-related AGE presence in tissue, such as the retina, which becomes the site of the eye disease.”

The research, published online in October in the journal Aging Cell traces the drop-off in AGE accumulation in the lower GI diet to the ubiquitin-protease system pathway and the lysosome/autophagy pathway. “In cell models we saw that both the ubiquitin pathways and lysosome pathways processed proteins more efficiently and kept cells healthier when glucose levels were lower,” says Taylor, who is also a professor at the Friedman School and Tufts University School of Medicine (TUSM). “Both pathways are well-known for their ability to remove damage from cells, but this had not been previously systematically explored for removal of AGEs.”

The Centers for Disease Control reports AMD is the chief cause of irreparable vision loss in Americans over age 65 and that 1.8 million people in the U.S. are living with the disease, a number that is expected to approach 3 million by 2020.

“Although our laboratory has shown in epidemiological studies and now in a live laboratory model that lower GI diets may prevent or delay the progression of AMD, future studies are needed. Trials involving more animals and human clinical trials could more carefully describe the protein-editing machinery that appeared to determine the development and severity of the lesions we saw,” Taylor says. “With such information, we may begin to develop cost-effective dietary interventions as well as a new generation of drugs that mimic the presumed effects of the lower GI diet to prolong vision.”

The authors received funding for this study from the USDA, Johnson & Johnson Focused Giving and the National Institutes of Health (NIH).

Uchiki T, Weikel KA, Jiao W, Shang F, Caceres A, Pawlak D, Handa JT, Brownlee M, Nagaraj R, and Taylor A. “Glycation-Altered Proteolysis as a pathobiologic mechanism that links dietary glycemic index, aging and age-related disease (in non-diabetics). Aging Cell. Published online October 3, 2011. DOI: 10.1111/j.1474-9726.2011.00752.x

About Tufts University School of Nutrition

The Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University is the only independent school of nutrition in the United States. The school's eight degree programs, which focus on questions relating to famine, hunger, poverty, and communications, are renowned for the application of scientific research to national and international policy. For three decades, the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University has studied the relationship between good nutrition and good health in aging populations. Tufts research scientists work with federal agencies to establish the USDA Dietary Guidelines, the Dietary Reference Intakes, and other significant public policies.

Andrea Grossman | Newswise Science News
Further information:
http://www.tufts.edu

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>