Can Rudolph help researchers understand cartilage regeneration

Reindeer antlers are made of cartilage and bone and are covered with soft, furry skin called velvet.  At the height of summer, male antlers grow an astonishing 1.5 – 2.5 centimeters a day – faster than any other developing mammalian bone.   In the winter, the antlers fall off, only to regrow again in the spring in much the same pattern.  Dr. John Matyas, McCaig Institute member and professor in the Faculty of Veterinary Medicine at the University of Calgary wants to understand the causes behind this amazing growth. “Antlers are the only mammalian organ that completely regenerates, year after year,” says Matyas.   “If we could understand how antler bone and cartilage grows and regenerates so quickly, we may be able to apply that knowledge to human bone.”

He believes it all has to do with stem cells.

Antler growth is triggered by hormones and begins in a small bump on the skull called a pedicle.  Inside this pedicle there are stem cells - cells that can become any type of tissue and divide and grow very quickly in a controlled manner.  The stem cells in reindeer antlers are programmed to either make more stem cells or turn into cartilage, bone or skin.

Antlers start off as cartilage.  As the cartilage matures, bone starts growing on top of it - but the cartilage continues to grow lengthwise at the tip.  Once the antler has achieved its full size after rutting season, hormones trigger the release of cells called osteoclasts that stop cartilage growth.  The velvet dies, the entire antler hardens to bone, and the antlers eventually fall off.  Then the whole process starts again the next spring.

Matyas and his colleagues take samples of antler bone, cartilage and skin to look at their structures.  They are studying the biology and growth of the tissues, trying to understand the role stem cells play in their development. “In humans, once you damage cartilage, it doesn’t repair itself,” says Matyas.  “Discovering the secret behind cartilage regeneration is ‘the Holy Grail.’  If we can understand what makes this explosive growth of cartilage in antlers, maybe we can reproduce it using tissue engineering.”

Dr. John Matyas is a member of the McCaig Institute for Bone and Joint Health, and a Professor of Comparative biology and Integrative Medicine in the Faculty of Veterinary Medicine at the University of Calgary.  His research focuses on joint tissue biomechanics and the causes and treatments of degenerative joint disease.