WHAT CAUSES OSTEOARTHRITIS?Although once thought of as a wear-and-tear disease, a new theory holds that osteoarthritis is a chemical disease of cartilage, the material that covers the ends of the bones where they join. Cartilage has a high water content and is mostly made up of a gel-like protein called collagen. Cartilage acts as a shock absorber, cushioning the bones and preventing them from grinding against each other as they move. Osteoarthritis may be the result of an imbalance in the normal breakdown and buildup of cartilage.One item of evidence has helped overturn the wear-and-tear theory: Joints have a low friction level, so they don’t wear out by themselves unless they are used excessively or are injured.5 Also, while osteoarthritis does occur more frequently in joints that have been stressed or damaged, it can also occur in uninjured joints. Furthermore, osteoarthritis frequently develops in many joints at the same time, often on both sides of the body symmetrically, even when there is no reason to believe that joints on both sides of the body have been subjected to equal amounts of wear and tear.Another intriguing clue is that osteoarthritis of the knee is commonly (and mysteriously) associated with osteoarthritis of the hands. These factors as well as others have led to the suggestion that osteoarthritis may actually be a systemic, or body-wide, disease of the cartilage.Osteoarthritis may be the result of an imbalance in the normal breakdown and buildup of cartilage.Cartilage is primarily made of two types of substances: proteoglycans and collagen. Proteoglycans stiffen the tissue and give it the ability to withstand the pressure placed on joints, for instance when you are lifting heavy objects. Collagen fibers give it strength to hold together even when stretched and ground between the bones it protects.The cartilage in your body is constantly being turned over by a balance of forces that both break it down and rebuild it. One prevailing theory suggests that osteoarthritis may represent a situation in which the forces that break down cartilage get out of hand for reasons that are unknown. We do know that substances called metalloproteinases, plasmin, and cathepsins all play a role in destroying cartilage, and they are found in increased amounts in the joints of those suffering from osteoarthritis. There is some evidence that chondroitin may slow joint deterioration by interfering with enzymes that help the breaking-down process.The first changes seen in osteoarthritis involve an abnormality of cartilage. These abnormalities include subtle disruptions in the network of fibers that make up the cartilage. In response to the damage, rebuilding mechanisms take effect, increasing production of collagen and proteoglycans.Certain natural supplements, such as glucosamine, S-adenosylmethionine, and chondroitin, may be able to support this rebuilding mechanism.Even after osteoarthritis has begun, these compensating mechanisms can keep the joint functioning well for several years. Because the cartilage has been damaged, it may thicken, but it still functions. The phase of osteoarthritis during which the joint remains functioning is called “compensated” or “stabilized” osteoarthritis. Eventually, however, unaided building forces cannot keep up with destructive ones, and what is called “end-stage” osteoarthritis develops. End-stage osteoarthritis results in the all-too-familiar picture of arthritic pain and impaired joint function.*10/306/5*
Although once thought of as a wear-and-tear disease, a new theory holds that osteoarthritis is a chemical disease of cartilage, the material that covers the ends of the bones where they join. Cartilage has a high water content and is mostly made up of a gel-like protein called collagen. Cartilage acts as a shock absorber, cushioning the bones and preventing them from grinding against each other as they move. Osteoarthritis may be the result of an imbalance in the normal breakdown and buildup of cartilage.
One item of evidence has helped overturn the wear-and-tear theory: Joints have a low friction level, so they don’t wear out by themselves unless they are used excessively or are injured.5 Also, while osteoarthritis does occur more frequently in joints that have been stressed or damaged, it can also occur in uninjured joints. Furthermore, osteoarthritis frequently develops in many joints at the same time, often on both sides of the body symmetrically, even when there is no reason to believe that joints on both sides of the body have been subjected to equal amounts of wear and tear.
Another intriguing clue is that osteoarthritis of the knee is commonly (and mysteriously) associated with osteoarthritis of the hands. These factors as well as others have led to the suggestion that osteoarthritis may actually be a systemic, or body-wide, disease of the cartilage.
Osteoarthritis may be the result of an imbalance in the normal breakdown and buildup of cartilage.
Cartilage is primarily made of two types of substances: proteoglycans and collagen. Proteoglycans stiffen the tissue and give it the ability to withstand the pressure placed on joints, for instance when you are lifting heavy objects. Collagen fibers give it strength to hold together even when stretched and ground between the bones it protects.
The cartilage in your body is constantly being turned over by a balance of forces that both break it down and rebuild it. One prevailing theory suggests that osteoarthritis may represent a situation in which the forces that break down cartilage get out of hand for reasons that are unknown. We do know that substances called metalloproteinases, plasmin, and cathepsins all play a role in destroying cartilage, and they are found in increased amounts in the joints of those suffering from osteoarthritis. There is some evidence that chondroitin may slow joint deterioration by interfering with enzymes that help the breaking-down process.
The first changes seen in osteoarthritis involve an abnormality of cartilage. These abnormalities include subtle disruptions in the network of fibers that make up the cartilage. In response to the damage, rebuilding mechanisms take effect, increasing production of collagen and proteoglycans.
Certain natural supplements, such as glucosamine, S-adenosylmethionine, and chondroitin, may be able to support this rebuilding mechanism.
Even after osteoarthritis has begun, these compensating mechanisms can keep the joint functioning well for several years. Because the cartilage has been damaged, it may thicken, but it still functions. The phase of osteoarthritis during which the joint remains functioning is called “compensated” or “stabilized” osteoarthritis. Eventually, however, unaided building forces cannot keep up with destructive ones, and what is called “end-stage” osteoarthritis develops. End-stage osteoarthritis results in the all-too-familiar picture of arthritic pain and impaired joint function.
*10/306/5*
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