Nω-(carboxymethyl)arginine Accumulates in Glycated Collagen and Klotho-deficient Mouse Skin

Objective: Advanced glycation end products (AGEs) accumulate in tissues due to aging, diabetic complications, and atherosclerosis. The acid lability of Nω-carboxymethylarginine (CMA) present in glycated collagen has hampered detailed studies on its function and in vivo localization. In the present study, we analyzed the effects of collagen glycation on human dermal fibroblast (HDF) function. We also took advantage of Klotho-deficient mice ( kl/kl), which undergo accelerated senescence, to determine glycated collagen’s tissue localization. Methods: Bovine type I collagen was incubated with ribose, and CMA formation was measured by enzyme-linked immunosorbent assay (ELISA). We measured the contraction of 3-dimensional matrix gels (3D gel), consisting of either native or glycated collagens, after culture with HDFs. CMA accumulation in Klotho-deficient mouse skin was measured by immunohistochemical staining. Results: When collagen was incubated with ribose, CMA levels increased with time. In our HDF culture system, gels prepared with native, but not glycated collagen, contracted with time. In Klotho-deficient mice, CMA localized to the extracellular dermal matrix. Conclusions: Here we show that CMA may provide a marker for collagen glycation, which may adversely affect HDFs’ growth and survival. Therefore, treatment with AGE inhibitors might help prevent pathologies associated with AGE formation.