Oral Fluid–Based Biomarkers of Alveolar Bone Loss in Periodontitis

Periodontal disease is a bacteria-induced chronic inflammatory disease affecting the soft and hard supporting structures encompassing the teeth. When left untreated, the ultimate outcome is alveolar bone loss and exfoliation of the involved teeth. Traditional periodontal diagnostic methods include assessment of clinical parameters and radiographs. Though efficient, these conventional techniques are inherently limited in that only a historical perspective, not current appraisal, of disease status can be determined. Advances in the use of oral fluids as possible biological samples for objective measures of current disease state, treatment monitoring, and prognostic indicators have boosted saliva and other oral-based fluids to the forefront of technology. Oral fluids contain locally and systemically derived mediators of periodontal disease, including microbial, host-response, and bone-specific resorptive markers. Although most biomarkers in oral fluids represent inflammatory mediators, several specific collagen degradation and bone turnover-related molecules have emerged as possible measures of periodontal disease activity. Pyridinoline cross-linked carboxyterminal telopeptide (ICTP), for example, has been highly correlated with clinical features of the disease and decreases in response to intervention therapies, and has been shown to possess predictive properties for possible future disease activity. One foreseeable benefit of an oral fluid–based periodontal diagnostic would be identification of highly susceptible individuals prior to overt disease. Timely detection and diagnosis of disease may significantly affect the clinical management of periodontal patients by offering earlier, less invasive, and more cost-effective treatment therapies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73247/1/annals.1384.028.pd

Role of Matrix Metalloproteinases and Therapeutic Benefits of Their Inhibition in Spinal Cord Injury

This review will focus on matrix metalloproteinases (MMPs) and their inhibitors in the context of spinal cord injury (SCI). MMPs have a specific cellular and temporal pattern of expression in the injured spinal cord. Here we consider their diverse functions in the acutely injured cord and during wound healing. Excessive activity of MMPs, and in particular gelatinase B (MMP-9), in the acutely injured cord contributes to disruption of the blood-spinal cord barrier, and the influx of leukocytes into the injured cord, as well as apoptosis. MMP-9 and MMP-2 regulate inflammation and neuropathic pain after peripheral nerve injury and may contribute to SCI-induced pain. Early pharmacologic inhibition of MMPs or the gelatinases (MMP-2 and MMP-9) results in an improvement in long-term neurological recovery and is associated with reduced glial scarring and neuropathic pain. During wound healing, gelatinase A (MMP-2) plays a critical role in limiting the formation of an inhibitory glial scar, and mice that are genetically deficient in this protease showed impaired recovery. Together, these findings illustrate complex, temporally distinct roles of MMPs in SCIs. As early gelatinase activity is detrimental, there is an emerging interest in developing gelatinase-targeted therapeutics that would be specifically tailored to the acute injured spinal cord. Thus, we focus this review on the development of selective gelatinase inhibitors

Inhibition of matrix metalloproteinase-14 in osteosarcoma cells by clodronate

Background. Bisphosphonates reduce the bone metastasis formation and angiogenesis but the exact molecular mechanisms involved are unclear. Progelatinase A (proMMP-2; 78 KDa) is activated up during the tumor spread and metastasis by a cell surface-associated matrix metalloproteinase (membrane-type matrix metalloproteinase [MT1-MMP] or MMP-14). Material and methods. We evaluated the effects of a bisphosphonate (clodronate) on MT1-MMP mRNA expression and protein production, catalytic activity and proteolytic activation of proMMP-2 by cultured human MG-63 osteosarcoma cells. Results. Clodronate, at therapeutically attainable noncytotoxic concentrations, dose-dependently inhibited phorbol myristic acetate (PMA)-induced proteolytic activation of proMMP-2 by human MG-63 osteosarcoma cells. Clodronate also downregulated the PMA-induced expression of MT1-MMP mRNA and protein production in human MG-63 osteosarcoma cells, as evidenced by Northern analysis and fluorescent immunohistochemistry. Furthermore, clodronate inhibited directly and dose-dependently MT1-MMP activity, and the MT1-MMP inhibition by clodronate was reduced in the presence of an increased (5 mM) Ca2+ concentrations when compared to physiological (1 mM) Ca2+ concentrations. Conclusion. We conclude that (1) the extracellular/cell-associated mechanism of bisphosphonate involves inhibition of MT1-MMP catalytic activity eventually by chelation, and that (2) intracellular mechanism involves downregulation of induced MT1-MMP mRNA and protein expression. The inhibition and downregulation of MT1-MMP by clodronate can be related to their ability to reduce MG-63 osteosarcoma cell invasion and spread. These findings may, at least in part, explain at molecular level the antitumor and antibone resorption activities of clodronate observed in clinical studies. © 2003 Elsevier Inc. All rights reserved

Activation of type IV procollagenases by human tumor-associated trypsin-2

Sorsa T, Salo T, Koivunen E, et al. Activation of type IV procollagenases by human tumor-associated trypsin-2. JOURNAL OF BIOLOGICAL CHEMISTRY. 1997;272(34):21067-21074.Increased production of proteinases, such as matrix metalloproteinases (MMPs), is a characteristic feature of malignant tumors. Some human cancers :Ind cell lines derived from them also express trypsinogen, but the function of the extrapancreatic trypsin has remained unclear, In this study we cloned and sequenced trypsinogen-a cDNA from human COLO 205 colon carcinoma cells and characterized the ability of the enzyme to activate latent human type TV procollagenases (proMMP-2 and proMMP-9). As shown by cloning and N-terminal amino acid sequencing, the amino acid sequence of tumor associated trypsin-a is identical to that of pancreatic trypsin-a. We found that both pancreatic trypsin-a and tumor cell-derived trypsin-a are efficient activators of proMMP-9 and are capable of activating proMMP-9 at a molar ratio of 1:1000, the lowest reported so far. Human trypsin-a was a more efficient activator than widely used bovine trypsin and converted the 92-kDa proMMP-9 to a single 77-kDa product that was not fragmented further. The single peptide bond cleaved by trypsin-a in proMMP-9 was Arg(87)-Phe(88), The generation of the 77-kDa species coincided with the increase in specific activity of MMP-9. In contrast, trypsin-2 only partially activated proMMP-2. Trypsin-a cleaved the Arg(99)-Lys(100) peptide bond of proMMP-2 generating 62-65-kDa MMP-2 species. Trypsin-a-induced proMMP-2 and -9 conversions were inhibited by tumor-associated trypsin inhibitor added either prior to or during activation indicating that proMMPs were not activated autocatalytically. Trypsin-2 also activated proMMPs associated with tissue inhibitor of matrix metalloproteinases, the complexes of which are thought to be the major MMP forms in vivo. The ability of human tumor cell-derived trypsin-a to activate latent MMPs suggests a role fbr trypsin-a in initiating the proteinase cascade that mediates tumor invasion and metastasis formation