Advances in the treatment of canine arthritis

Canine osteoarthritis (OA) is a slowly progressive degenerative joint disease, and it is one of the most common causes of chronic pain in dogs. It often occurs secondary to previous trauma or conditions such as osteochondritis dissecans (OCD) or elbow, shoulder or hip dysplasia. In fact, as many as 30 to 40 percent of dogs have clinical signs of arthritis1. With widespread implications for welfare and quality of life, effective diagnosis and management of canine arthritis is key.


Multi-modal management

A multi-modal approach to the management of canine arthritis is advocated, including weight and exercise management, pharmaceuticals, chondroprotection, physiotherapy, hydrotherapy and newer technologies such as pulsed electromagnetic field therapy (PEMF).

Canine obesity: not just the weight

An obesity epidemic is having global implications for human health, and sadly dogs are not far behind. Although figures for canine obesity prevalence vary widely it is without doubt, an ever-increasing problem and quoted figures are likely to represent the tip of the iceberg.

Obesity hastens the progression of osteoarthritis in dogs, due to increased weight-bearing and joint stress. However, it is increasingly recognised that being overweight has wider implications. Fat is not an inert tissue, and releases inflammatory mediators; this inflammatory response can worsen arthritic pain.

So obesity is now considered a chronic inflammatory disease and the importance of weight loss, both for the management of arthritic pain but also for general health should not be under-estimated. Exercise, along with diet, will help with weight management, and as long as this exercise is regular and low-impact, can also help manage arthritic pain.

Non-steroidal anti-inflammatory drugs: the mainstay of pain management

Alongside lifestyle changes, pain management must be considered. Non-steroidal anti-inflammatory drugs (NSAIDs) are widely used and are the cornerstone for the management of pain associated with canine arthritis. NSAIDs work by inhibiting enzymes called cyclo-oxygenases, of which there are two types – COX-1 and COX-2. COX-1 is responsible for the formation of prostaglandin-1 (PG-1) which has a ‘house-keeping’ role, helping to maintain the stomach lining and controlling renal blood flow. COX-2 is responsible for the formation of prostaglandin-2 (PG-2), which is involved in inflammation.

The adverse renal and gastrointestinal (GI) side effects of NSAIDs are largely due to COX-1 inhibition, so newer NSAIDs are more targeted, focusing on COX-2 inhibition, and preserving the actions of COX-1.

Non-COX inhibiting NSAIDs, such as grapiprant, also have a reduced impact on the kidneys and GI system. Grapiprant is a prostaglandin receptor antagonist, which blocks the EP4 receptor, a primary mediator of canine arthritis pain and inflammation in dogs2.

While NSAIDs are a mainstay of pain management in canine arthritis, they may have a number of contraindications, including in animals with cardiac, renal or hepatic disease, or those where there is a risk of gastrointestinal bleeding. Historically, alternative treatment options for these patients have been relatively limited, but that picture has been changing…

Monoclonal antibodies: the new kids on the block

For over 30 years. monoclonal antibodies (mAbs) have been revolutionising the treatment of many human diseases, and they show great promise for achieving the same feat in veterinary medicine.

Bedinvetmab is one such mAb. It targets nerve growth factor (NGF) and is used for managing the pain associated with osteoarthritis. NGF is produced and used by many different cell types, and it is particularly important during fetal and neonatal neuronal development. However in adults NGF has less obvious benefits, being involved with chronic inflammation, pain pathways, and wind-up (central sensitisation)3.

In canine arthritis, NGF binds to the tropomyosin receptor kinase A (TrkA) receptor, located on nociceptors within the joints. Targeting NGF in this way, with a canine-specific mAb disrupts the pain pathway. This becomes particular important in diseased joints when production of NGF is increased.

The advantages of monoclonal antibodies as a treatment option include:

  • Monoclonal antibodies function just like naturally occurring antibodies, to target a particular antigen (NGF in the case of canine arthritis) and block pain transmission.
  • Monoclonal antibodies are eliminated by normal protein degradation by endogenous proteases so there is no, or minimal renal or hepatic involvement4.
  • With a specific target (nociceptors within joints), GI and renal side effects are much less likely.

Pain management: a team approach

However before even considering treatment options, the first hurdle to overcome in managing canine arthritis, is the lack of owner awareness surrounding this condition. Owners often interpret changes in their older pets as just ‘slowing down’ or old age, when in reality the loss of enthusiasm for life is due to chronic pain. Involving owners in their pet’s care at all stages and enhancing their understanding of canine arthritis will help ensure that they engage with a treatment plan, ultimately improving clinical outcomes.

Why not use digital communication aids, such as VisioCare Consult in your consulting room? With a cloud-based library of peer-reviewed content, from animations and videos to owner factsheets, VisioCare Consult helps support effective communication, saving you time and improving outcomes.


References

  1. Johnson, J.A. et al. (1994) Incidence of canine appendicular musculoskeletal disorders in 16 veterinary teaching hospitals from 1980 through 1989. Vet Comp Orthop Traumatol7: 56– 69
  2. Kirkby Shaw K. et al. (2016) Grapiprant: an EP4 prostaglandin receptor antagonist and novel therapy for pain and inflammation. Vet Med Sci; 2:3-9
  3. Aloe, L. et al. (2015) Nerve growth factor: a focus on neuroscience and therapy. Cur Neuropharmacol; 13: 294– 303
  4. Epstein, M.E. (2019) Anti-nerve growth factor monoclonal antibody: a prospective new therapy for canine and feline osteoarthritis. Vet Rec;184(1):20-22

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