Good as Gold? More Research Supports Glucosamine

Questions and concerns abound surrounding the use of oral joint health supplements for horses with osteoarthritis, and so researchers continue their quest to determine if and how glucosamine works to decrease pain and inflammation caused by osteoarthritis.

"Osteoarthritis is one of the most important and widespread performance-limiting problems facing horses and horse owners," said researcher Christopher Byron, DVM, MS, Dipl. AVCS, of the College of Veterinary Medicine at the University of Illinois. "Although we have access to many effective treatment options, there is still a need for economical treatments which preserve or improve the joint environment. Glucosamine is an attractive option since it is readily available, easy to administer, and safe. Unfortunately, our understanding of how it may benefit the osteoarthritic joint is incomplete."

 

"Glucosamine is an attractive option since it is readily available, easy to administer, and safe. Unfortunately, our understanding of how it may benefit the osteoarthritic joint is incomplete." --Dr. Christopher Byron

Byron and colleagues reported the results of two studies in the September 2008 edition of the American Journal of Veterinary Research. One of the key features that sets this research apart from prior studies is that physiologically relevant doses of glucosamine were studied. That is, amounts of glucosamine that can be achieved via oral administration in live animals.

In the first study, "Effects of methylprednisolone acetate and glucosamine on proteoglycan production by equine chondrocytes in vitro," chondrocyte (cartilage cell) pellets were prepared by collecting articular cartilage from eight horses. The pellets were then incubated with glucosamine before adding the corticosteroid methylprednisolone acetate (MPA)--a pharmaceutical drug that is commonly used intra-articularly (injected into the joint) in horses as an anti-inflammatory.

Confirming the results of previous studies, MPA decreased the production of proteoglycans by the chondrocytes.

"This means that MPA can, at certain concentrations, prevent cells in the joint from producing important components of cartilage." said Byron. "We also found that glucosamine had a protective effect on the chondrocytes as glucosamine protected the production of proteoglycans by the chondrocytes exposed to MPA."

In the companion study, "Effects of clinically relevant doses of glucosamine on equine chondrocytes and synoviocytes in vitro," Byron's research team evaluated the efficacy of glucosamine by culturing chondrocytes and synoviocytes (synovial cells that line the inside of the joint) with or without interleukin-1 (IL-1), a pro-inflammatory mediator.

According to Byron, "Glucosamine exerted only a limited effect on the metabolism of the chondrocytes and synoviocytes that were not exposed to IL-1; however, at certain concentrations glucosamine significantly decreased the production of some inflammatory mediators including prostaglandin E2 in the cultures exposed to IL-1."

Together, these data support the use of glucosamine in combination with intra-articular administration of MPA (and possibly other corticosteroids), as well as in inflamed joints such as those with osteoarthritis.

"While we are excited by these findings and believe that glucosamine can be a useful adjunct to a comprehensive treatment protocol, the real test will be in future studies looking at effects in clinical cases. There is a genuine need for future research focusing on what is happening to the joint in the afflicted equine athlete when glucosamine is administered," summarized Byron.

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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