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Collagens, especially Type I collagen, are the primary structural proteins in the body. They sustain mechanical bodily stresses, support different types of cells, and serve as anchors for various growth factors. The collagen-peptides produced when collagens are cleaved by enzymatic activities also exhibit potent biological activities. As highly biocompatible molecules with potent biological functions, the collagens have garnered wide interest as biomedical materials, in particular, for tissue repair and regeneration. This review first provides a brief introduction to collagen structure and classification, and then primarily focuses on the current development of collagen-based biomaterials, with emphasis on collagen-based scaffolding materials for tissue regeneration. [ABSTRACT FROM AUTHOR]

Background: Members of the matrix metalloproteinase (MMP) family have been shown to be involved in periodontal disease. Risk factors for periodontal disease include tobacco smoking. Cigarette smoke condensate (CSC) is comprised of thousands of chemicals. Nicotine is one of the active components in tobacco. This study compares the effects of CSC and nicotine at the level in CSC on the collagen-degrading ability of human gingival fibroblasts (HGFs) and the expression of selected MMPs and tissue inhibitors of metalloproteinases (TIMPs). Methods: HGFs were seeded in six-well collagen-coated plates, exposed to 100 µg/mL (2.4 µg/mL nicotine) of CSC or 2.4 µg/mL nicotine for 3 days, and then collagen degradation was analyzed. After 3 days exposure to CSC or nicotine, the conditioned media from HGFs was collected and the membrane proteins were extracted for gelatin zymography and Western blot analyses. The mRNA levels of MMP-2, MMP-14, and TIMP-2 were measured by reverse transcription-polymerase chain reaction. Results: The CSC increased collagen degradation, and increased the levels of TIMP-2, MMP-14, and the active MMP-2 in the membrane extracts, and their mRNA levels. CSC also increased the level of active MMP-2 in the conditioned media. Nicotine at the level in CSC (2.4 µg/mL) had little influence on collagen degradation, as well as on the protein and mRNA levels of MMP-2, MMP-14, and TIMP-2. Conclusions: CSC may increase HGF-mediated collagen degradation by affecting membrane-associated MMPs and TIMPs. [ABSTRACT FROM AUTHOR]