Dr. Gary Edelson, DVM
A pet does not have to be older to require joint care supplementation or pain control. Degenerative joint disease (DJD), also referred to as arthritis, can affect any joint but commonly affects the hip, knee (stifle), ankle (hock), elbow, wrist (carpus) and even the spine (intervertebral joints) of pets. Arthritis occurs when the joint cartilage is affected, either through a traumatic event, chronic wear and tear, and obesity or when the joint is congenitally abnormal.
The Science of Arthritis
The anatomy of the joint and the disease process is very important to understand when discussing the actions of different medications. There are several different types of joints within an animal’s body. When discussing arthritis, the joints we are often concerned about are synovial joints (also called diarthrodial joints). Synovial joints are made up of two bones and a fibrous capsule holding the two bones together. It is like a hinge made of fiber and bone, but more complicated. The surfaces of the bone ends are covered with smooth cartilage (called articular cartilage) that must be able to slide easily across each other and act as a cushion throughout a pet’s life.
The articular cartilage is made up of a matrix, which is the material where the cartilage cells are suspended, like fruit suspend in Jell-O. Collagen and proteoglycans form the matrix. Collagen is a medical word that most are familiar with which is a support protein that is tough, holding everything together from skin to bone in the proper shape.
Proteoglycan is not a common word, but is found in many supplements, so it is worth discussing. It is the material surrounding the collagen fibers made up of a long protein molecule with strands called glycosaminoglycans (GAGs) growing off its sides like bristles on a brush. It is the GAG bristles that give cartilage its soft characteristic by allowing the proteoglycan molecule to soak up water like a sponge, but stays very slick to allow the two bones to move across one another. Articular cartilage also contains chondrocytes, which are the cells that produce the cartilage matrix.
An important word not to skip over is glycosaminoglycan (GAGs). The three GAGs that can make up proteoglycan molecule are: chondroitin sulfate, keratan sulfate (is made in the animal’s body from glucosamine) and dermatan sulfate.
Dr. Gary, why should I know these complex words?
These substances are found in most veterinary nutritional joint supplements.
Hyaluron is the last GAG that is needed to know about and is responsible for binding and connecting the proteoglycans together in the matrix. It is the major factor of the joint lubricating fluid.
The joint capsule encloses the joint to create the structure of the hinge. The outer capsule layer is very tough and the inner layer is responsible for secreting the thick joint fluid (hyaluron) that provides both nutrition and lubrication for the joint. To keep the joint smooth and slippery, the capsule must keep unwanted substances out only let selective ones into the joint.
Arthritis results when the smooth cartilage becomes rough. The rough cartilage can then wear down, chip or flake leading to inflammation and the reduction of joint function. Impurities are now able to enter the joint affecting the lubricating fluid and ultimately a painful joint in our pet.
Arthritis is the number one cause of chronic pain in dogs and cats. While surgery may be available in some situations, most of the time the degeneration of the joint cannot be reversed and treatment focuses on preventing the progression of joint damage. Numerous supplements are available for the treatment of arthritis and is best treated with a multi-modal approach where several therapies combined give a better result compared to any single therapy.
One of these therapies are slow-acting drugs. They can improve joint function and can help with pain control, but require weeks to months for their full effects.
What are the major components in arthritis therapies?
Glucosamine and Chondroitin Sulfate
In a normal joint, cartilage breakdown is balanced by cartilage production, whereas in arthritis, there is more breakdown of cartilage. Glucosamine and chondroitin sulfate are part of cartilage and the theory is by taking these cartilage components, the pet’s body can use them to repair and rebuild cartilage where damaged. It is has also be hypothesized that these substances may have anti-inflammatory effects and may stimulate production of joint lubricants and collagen within the affected joints.
Glucosamine and chondroitin sulfate are extracted from sea mollusks (such as the New Zealand green lipped mussel). One to two months are needed for them to reach adequate levels.
Omega 3 Fatty Acids
Coldwater fish oils have been found to have anti-inflammatory properties. Primarily used in the treatment of allergic and itchy skin conditions, but many arthritic pets have benefited from omega three fatty acid supplementation. Flax seed oil is readily converted to omega three fatty acids in the human body, but this conversion is not as effective in animals. Flax seed oil supplementation is not needed in pet foods/supplements.
Methyl sulfonyl methane (MSM) is another anti-inflammatory agent and is derived from DMSO (dimethyl sulfoxide) for commercial sale. Natural MSM is found in plant and animal tissues, but not used for pet supplements. MSM is primarily used to provide additional building blocks for cartilage repair, but also its anti-inflammatory properties and may acts as an anti-oxidant.
Anti-oxidant and Free Radical Scavengers
Free radicals are harmful biochemicals that affect our pets from external sources like sunlight and pollution, or their body can make them as by-products of oxygen use. The free radicals are extremely reactive and attack structural proteins and cause production of inflammatory proteins. Pets normally use natural anti-oxidants to inactivate free radicals and in theory, supplementing with additional anti-oxidants can delay age-rated changes.
Prescription veterinary nonsteroidal anti-inflammatory drugs (NSAIDs) are also very important in the control of immediate and long-term pain and inflammation. Discuss this therapy with your veterinarian to see if it is appropriate for your pet.
Prevention of arthritis is about preserving the normal structures of a joint. Often this entails providing the biochemical components of these structures as nutraceutical supplements.
If a pet owner suspects that their dog or cat is suffering from arthritis, they should bring it to their veterinarian’s attention. If diagnosed, arthritis can be well managed with diet, supplementation, physical therapy/exercise and pain control medications.
Do you have pet health questions? Email Dr. Edelson here!