Exposure to cadmium is linked to the development of bone diseases such as osteoporosis. The mechanism by which cadmium leads to these diseases remains unclear. One possibility is that cadmium interferes with collagen in bone ECM. We hypothesize that cadmium binds collagen directly and interferes with collagen fibril assembly in the ECM produced by osteoblasts. Cell-free assays were utilized to investigate binding interactions between cadmium and type I collagen. Cell viability and collagen deposition were assessed in cell culture studies using Saos-2 cells induced to mineralize and treated with or without cadmium. Results indicate cadmium binds to type I collagen with a higher affinity than calcium and alters collagen fibrillogenesis. Cadmium exposure leads to condensed type I collagen distribution in ECM of cultured Saos-2 cells, possibly due to altered fibrillogenesis. Preliminary in vivo studies indicate significant bone pathology in rats treated with 12 weeks of cadmium. These studies will help elucidate the mechanism by which cadmium exposure can lead to bone diseases and ultimately aid in our fight against them.

The effects of cadmium on type I collagen in the extracellular matrix of osteoblast-like Saos-2 cells.