ROSA, C.; BLAKE, J.E.; O’HARA, T.M.; MONNIER, V.: Collagen Aging in the Bowhead Whale (Balaena mysticetus)

Age in marine mammals may be determined by various methods, ranging from simple photo re-identification to such methods as ear plug growth layer measurement, tooth growth layer group quantification, aspartic acid racemization in the teeth and eye lens nucleus, and the aging of baleen. In bowhead whales (Balaena mysticetus), teeth are not present, ear plugs do not appear to form and baleen aging is reliable only up to eleven years of age. This study evaluates the potential to age whales via the analysis of a small amount of skin (from a biopsy dart sample or collection at necropsy). Manifestations of aging are most pronounced in the extracellular matrix, the primary component of which is collagen. Collagen cross-links increase with age and advanced glycation end-products, such as pentosidine and carboxy-methyl lysine, accumulate in long-lived tissue proteins. Pentosidine, a marker of glycoxidative stress in skin collagen, forms at a rate inversely related to maximum life span across several mammalian species. Through support from the Alaska EPSCoR program, we have quantified the levels of pentosidine and other collagen related products in the dermis of 48 bowhead whales. Pentosidine is present at very low levels in bowhead whale dermal collagen, suggesting that these tissues do not age appreciably or that glycation end-products in marine mammals differ from terrestrial mammals.