Dogs Are Helping Advance the Understanding and Treatment of ACL Injuries

More than just loyal companions, dogs are proving to be valuable allies in medical research. A new study has shown that humans and dogs share key proteins that could speed up the understanding and treatment of complications related to anterior cruciate ligament (ACL) injuries — a condition common to both species.

Comparative Oncology: A Model for Human Treatments

Recently, we highlighted how a U.S. biopharmaceutical company is using comparative oncology — the study of cancer in companion animals — to develop treatments for humans. This approach is already leading to therapies for bone cancer in both dogs and children.

Now, researchers at Cornell University have identified significant similarities between ACL injuries in humans and dogs, as well as in the healing processes. These findings could accelerate the development of more effective treatments.

“Our research reinforces the value of studying naturally occurring diseases in dogs to generate insights for human medicine,” said Sydney Womack, lead author of the study and a dual DVM and PhD candidate at Cornell’s College of Veterinary Medicine. “They live with us, share our food, go running and hiking with us – they’re probably the closest model we have to human lifestyles, and they represent a vast, untapped resource.”

Understanding the Anterior Cruciate Ligament and Injuries

The anterior cruciate ligament is a strong tissue band that connects the femur (thigh bone) to the tibia (shin bone) in the knee joint. Injuries to this ligament commonly occur during sports or activities that involve quick direction changes, jumping, or collisions. The severity ranges from slight stretching to full tears, resulting in knee instability. Treatment options range from physical therapy to reconstructive surgery.

Both humans and young dogs are prone to developing post-traumatic osteoarthritis (PTOA) after an ACL injury, particularly following surgical repair. However, the underlying mechanisms of PTOA are still not well understood. This study aimed to compare PTOA progression in humans and dogs to identify biological markers and potential therapeutic targets.

Researchers focused on the proteins found in synovial fluid — the viscous liquid in joints that lubricates cartilage and reduces friction. Using proteomics (the study of protein structure, interactions, and function), they discovered that 60% of the proteins found in humans were also present in dogs, while 67.4% of the proteins identified in dogs were detected in humans. Among the shared proteins, 31 showed significant differences between healthy individuals and those with ACL injuries. Of these, 28 were similarly up- or downregulated in both species.

“There are many shared targets between dogs and humans,” said Heidi Reesink, corresponding author and associate professor of clinical sciences at Cornell’s College of Veterinary Medicine, who also holds a joint position at the University of California, Davis. “This study shows the value of dogs as models for exploring questions that are difficult to address in humans, while also helping us develop better treatments for both.”

The Role of Periostin in Healing and Joint Degeneration

One particular protein in synovial fluid, periostin, stood out as the most upregulated — not only among the proteins shared by both species but also within each species.Periostin plays an important role in tissue repair and wound healing and researchers have also linked it to inflammation and cancer.

“There’s evidence that periostin is crucial during the early healing phase, but its prolonged overexpression might trigger chronic inflammation and joint degeneration,” Womack noted. “I’m currently studying periostin in mice to see whether reducing or eliminating its expression changes how the disease progresses.”

Because diseases like cancer and cardiovascular conditions are also associated with periostin, targeting this protein could lead to therapies that apply far beyond ACL injuries.

Reesink also expressed interest in understanding how it affects other joint diseases, including age-related arthritis and other traumatic injuries.“There’s potential to create shared treatments that target these molecular pathways and benefit a wide range of conditions across species.

Read the original article on: New Atlas

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