Hibernating Bears (Ursidae)

Metabolic Magicians of Definite Interest for the Nephrologist

Peter Stenvinkel; Alkesh H Jani; Richard J Johnson


Kidney Int. 2013;83(2):207-212. 

In This Article

Impaired Wound Healing in Uremia: Does Bear Serum Hold a Secret for Future Treatment?

Impaired would healing is an important clinical problem in chronic kidney disease patients, especially those that have diabetes and/or are malnourished.[46] Certain solutes that are retained in uremia, such as p-cresol and indoxyl sulfate, have been found to decrease endothelial cell proliferation and impair wound repair in vitro.[47] The American black bear, on the other hand, appears to be able to completely resolve cutaneous cuts and punctures incurred during or before hibernation despite being anuric.[48] The ability to heal wounds is a survival advantage in hibernating species in which decreased peripheral blood flow during hypothermia and immobilization may impede delivery of oxygen and nutrients to the wound site. Iaizzo et al.[48] have speculated that elevated levels of delta-opioid receptor antagonist and the major bile acid ursudeoxycholic acid (UDCA) observed during hibernation contribute to the amazing wound healing capacity of American black bears. The fact that hibernating bears secrete markedly higher concentrations of UDCA in their bile than non-hibernating bears is interesting since this remarkable molecule has been proposed as a remedy for many human diseases. Further studies of the underlying mechanisms involved in wound repair could lead to novel treatment approaches to improve wound healing and prevent bed sores in malnourished and diabetic uremic patients.