New role for zebrafish in human studies

Washington, May 20 (ANI): Zebrafish – an important animal model in disease and environmental studies – could eventually help scientists in revealing the function of a mysterious enzyme linked to the steroid cortisol, and found in the human brain, found a researcher at the University of California, San Diego School of Medicine.

In people and other vertebrates, steroids like cortisol perform a variety of diverse duties, including regulating immune response, bone formation and brain activity.

However, too much cortisol is unhealthy. High levels of the steroid have been linked to type 2 diabetes and may impair the brain”s ability to store memories.

The human body regulates cortisol by employing an enzyme called 11 beta-hydroxysteroid dehydrogenase-type 1 or 11beta-HSD1, which catalyzes the synthesis of cortisol in liver and fat cells.

A related enzyme known as 11 beta-HSD-type3 or 11 beta-HSD3 is expressed in the brain, though its utility remains unknown.

In new findings, Dr. Michael E. Baker has reported that 11 beta-HSD3 (but not 11 beta-HSD1) is present in zebrafish, where it appears to serve an important role in fish endocrine physiology.

This makes the fish a potentially useful analog for cortisol studies, including discovering the purpose and function of 11 beta-HSD3 in human brains, which may be an evolutionary precursor to 11 beta-HSD1.

Interestingly, Baker found that the genomes of mice and rats do not contain 11 beta-HSD3.

This means that inserting the appropriate gene for the enzyme in these animal models could provide additional avenues of investigation.

The study will be published in the latest issue of FEBS Letters. (ANI)

Maintaining energy balance may protect cyclists” bones during stage races

Washington, May 6 (ANI): A new University of Missouri research has suggested that elite cyclists should match their energy intake to the high-energy demands of stage racing to protect their bones.

Previous studies have demonstrated that competitive cyclists have significantly lower bone mineral density (BMD) than other endurance athletes, making them more vulnerable to fractures.

The reasons for the reduced bone mass in elite cyclists are not fully understood, but one explanation is an imbalance between bone formation and bone breakdown due to the high-energy cost of stage racing.

However, the latest study has shown that proper nutrition during multi-day stage races can prevent harmful changes in bone turnover.

The researchers involved in this study found that athletes who maintained energy balance by matching their energy intake to their energy expenditure showed increased markers of bone turnover – the process of breaking down old bone and forming new bone.

Because the increase in bone formation was greater than the increase in bone breakdown, the researchers concluded that these changes were not likely to negatively affect bone mass in the long-term.

“The findings suggest that participation in stage races might not have negative effects on bone turnover if energy intake matches the energy cost of high-intensity racing over several days,” said Pam Hinton, associate professor in the Department of Nutrition and Exercise Physiology.

“The results are consistent with the practical recommendation that elite cyclists should match their energy intake to the high energy demands of stage racing,” Hinton added.

In the study, Hinton examined markers of bone formation and bone breakdown in the blood of elite cyclists who participated in the Tour of Southland, a six-day, 10-stage cycling race.

Hinton found significant increases in markers of bone formation and bone breakdown among the athletes whose energy intake matched their energy expenditure throughout the race.

Disrupted bone turnover, that is, reduced bone formation and increased bone breakdown, due to inadequate energy intake relative to expenditure is just one possible cause of low BMD among cyclists.

Other factors include low-body weight, increased loss of calcium through sweat and significant time spent cycling, which exerts only minimal mechanical loading on the skeleton.

The study will be published in Applied Physiology Nutrition and Metabolism. (ANI)

New way to accelerate bone healing

London, Apr 27 (ANI): A group of researchers has found a way to significantly speed up the healing of broken bones in mice.

The feat which, if replicated in humans, could mean people with fractures would be free of their casts a lot sooner, reports Nature.

In the study, Roel Nusse and his colleagues at Stanford School of Medicine in Palo Alto, California, found that injecting mice with a family of proteins called Wnts — packed inside lipid bubbles, or liposomes — triggers new bone growth within a few days.

The finding has been published in Science Translational Medicine1.

Wnt proteins are known to stimulate bone formation and tissue regeneration, but scientists have not managed to turn them into drugs because the proteins are not very stable.

“It”s a major technological advance, and the fact that Wnts promote bone regeneration is an important finding,” says Gerard Karsenty, an expert in skeleton physiology at Columbia University in New York City. “They used a very clever way of delivering Wnts.” (ANI)

Tequila plant may help fight osteoporosis

Washington, March 24 (ANI): An ingredient in the plant that gave the world tequila may help protect against osteoporosis and other diseases, suggests a news study.

Foods spiked with “fructans” from the agave plant may be used in a new genre of processed foods with health benefits and as a source of nutrients that helps the body”s absorption of calcium, according to Mercedes López, National Polytechnic Institute, Guanajuato, Mexico.

López said: “Fructans are considered functional food ingredients because they affect body processes in ways that result in better health and reduction in the risk of many diseases.

“Experimental studies suggest that fructans may be beneficial in diabetes, obesity, stimulating the immune system of the body, decreasing levels of disease-causing bacteria in the intestine, relieving constipation, and reducing the risk of colon cancer.”

López and colleagues found mice fed agave fructans absorbed more calcium from food, excreted less calcium, and showed a 50 percent increase in levels of a protein associated with the build-up of new bone tissue.

The expert explained: “These results suggest that the supplementation of the standard diet with agave fructans prevented bone loss and improved bone formation, indicating the important role of agave fructans on the maintenance of healthy bone. They can be used in many products for children and infants to help prevent various diseases, and can even be used in ice cream as a sugar substitute.”

But López added: “We still have a long way to go to determine for which health benefits agave fructans perform better than chicory fructans. However, the early results are encouraging, and we working on it.”

The report was delivered at the 239th National Meeting of the American Chemical Society. (ANI)

Green tea may help improve bone health

Washington, Sept 17 (ANI): Green tea may help improve bone health, researchers in Hong Kong have reported.

The boffins found that the tea contains a group of chemicals that can stimulate bone formation and help slow its breakdown.

The study has been published in ACS’ Journal of Agricultural and Food Chemistry, a bi-weekly publication.

In the study, Ping Chung Leung and colleagues noted that many scientific studies have linked tea to beneficial effects in preventing cancer, heart disease, and other conditions.

To reach the conclusion, scientists exposed a group of cultured bone-forming cells (osteoblasts) to three major green tea components – epigallocatechin (EGC), gallocatechin (GC), and gallocatechin gallate (GCG) – for several days. They found that one in particular, EGC, boosted the activity of a key enzyme that promotes bone growth by up to 79 percent. EGC also significantly boosted levels of bone mineralization in the cells, which strengthens bones.

The scientists also showed that high concentrations of ECG blocked the activity of a type of cell (osteoclast) that breaks down or weakens bones. The green tea components did not cause any toxic effects to the bone cells, they noted. (ANI)

Gene behind gum disease, osteoporosis, arthritis identified

Washington, Aug 31 (ANI): An international team of researchers have identified a gene that is common in the development of gum disease, rheumatoid arthritis, and osteoporosis.

Experts at Hospital for Special Surgery say that their findings about the gene, called interferon regulator factor-8 (IRF-8), may lead to new treatments in future.

“The study doesn’t have immediate therapeutic applications, but it does open a new avenue of research that could help identify novel therapeutic approaches or interventions to treat diseases such as periodontitis, rheumatoid arthritis or osteoporosis,” said Nature magazine quoted Dr. Baohong Zhao, a research fellow in the Arthritis and Tissue Degeneration Program at Hospital for Special Surgery located in New York City, as saying.

The researchers discovered that downregulation of IRF-8 (meaning that the gene produces less IRF-8 protein) increases the production of cells called osteoclasts that are responsible for breaking down bone.

In humans and animals, bone formation and bone resorption are closely coupled processes involved in the normal remodelling of bone. Enhanced development of osteoclasts, however, can create canals and cavities that are hallmarks of diseases such as periodontitis, osteoporosis and rheumatoid arthritis.

The genome-wide study showed that the expression of IRF-8 was reduced by 75 percent in the initial phases of osteoclast development.

The genetically engineered mice deficient in IRF-8 had decreased bone mass and severe osteoporosis.

The researchers concluded that IRF-8 suppresses the production of osteoclasts.

“This is the first paper to identify that IRF-8 is a novel key inhibitory factor in osteoclastogenesis (production of osteoclasts),” said Zhao.

“We hope that the understanding of this gene can contribute to understanding the regulatory network of osteoclastogenesis and lead to new therapeutic approaches in the future,” Zhao added.

The study has been published in the journal Nature Medicine. (ANI)