Dr. Nobuo Suzuki at Division of Marine Environmental Studies analyzed bone disease due to diabetes using fish scales, and published the paper in Endocrine, volume 54.


The teleost fish has a unique hard tissue, scales that consist of osteoblasts, osteoclasts, and calcified bone matrix, including type 1 collagen, bone  γ-carboxyglutamic acid protein, osteonectin, and hydroxyapatite. In fish scales as well as bone, several calcemic hormones function in scale osteoblasts and osteoclasts as does in mammalian osteoblasts and osteoclasts. On the other hand, diabetes mellitus (DM), commonly referred to as diabetes, is a group of metabolic diseases that are characterized by chronic hyperglycemia. DM induces other pathologies, including bone disease, diabetic retinopathy, nephropathy, neuropathy, cardiomyopathy, and microangiopathy. Using the fish scales, we examined the effect of hyperglycemia on bone metabolism. After a 2-week exposure to hyperglycemia, the high molecular weight fractions of bone matrix collagen increased in the regenerating scales of hyperglycemic goldfish. This suggests that non-enzymatic cross-linking by advanced glycation end products (AGEs) was occurring in the regenerating scales of hyperglycemic goldfish. Using scale in vitro culture, furthermore, we demonstrated that glyceraldehyde-driven non-enzymatic cross-linking of collagen fibril compositions quickly increased with glyceraldehyde treatment. The findings of our in vitro study regarding glyceraldehyde-derived AGEs are in agreement with findings in diabetic rats. Therefore, we conclude that fish scales will help elucidate the molecular mechanisms of bone metabolic changes in human diabetic patients.

Journal title: Endocrine
Title: Fish scale is a suitable model for analyzing determinants of skeletal fragility in type 2 diabetes.
Authors: Suzuki, N., Kitamura, K. and Hattori, A.