Nazanin Narani

BACKGROUND: Manifestations of immunosuppression may take the form of opportunistic infection, and neoplasia. While this paper has focused on gingival and periodontal manifestations. these tissues cannot be evaluated in isolation. The presence of involvement of other oral tissues such as the cheek or tongue with manifestations associated with HIV such as hairy leukoplakia, Kaposi's sarcoma at these sites, and candidiasis in addition to periodontal manifestations may further increase the clincal suspicion of underlying immunosuppression and/or progression of the immunosuppressive state. DISCUSSION: The periodontist plays an essential r le in identifying the periodontal status of an individual and has an important r le to play in early recognition of signs and symptoms of HIV disease or progression of the medical condition. CONCLUSION: Only through such recognition can appropriate definitive diagnostic testing be conducted, and appropriate therapeutic intervention for the oral condition and the systemic condition be considered.

Enamel matrix proteins (EMP) induce periodontal regeneration and accelerate dermal wound healing, but the cellular mechanisms of these processes are unclear. We investigated the binding of EMP to the wound matrix proteins fibronectin, laminin-1, collagen type I, and collagen type IV and analyzed the interaction of epithelial cells and periodontal ligament fibroblasts (PDLF) with EMP and composite matrices of EMP + fibronectin or EMP + collagen. The adhesion of PDLF to EMP was concentration- and integrin-dependent and did not require de novo protein synthesis. EMP supported PDLF migration. In contrast, keratinocytes did not adhere to EMP if their protein synthesis was blocked. EMP showed concentration-dependent binding of fibronectin, peaking at 100 microg ml(-1) (before the precipitation point) of EMP. Type I collagen binding to EMP peaked at a low (1 microg ml(-1)) and narrow concentration range. Neither laminin-1 nor type IV collagen bound to EMP. Collagen and fibronectin, bound to EMP, showed significantly reduced (> 50%) binding of both epithelial cells and PDLF compared with the equivalent concentration of these proteins alone. PDLF, but not epithelial cell, adhesion was rescued by increasing the EMP concentration. These findings show that EMP binds to wound extracellular matrix proteins and regulates their adhesive properties. Such interactions may favor fibroblast adhesion over epithelial cells, potentially promoting connective tissue regeneration.

Wound contraction is a fundamental process in wound repair and is required for closure, but the interactions between the inflammatory cytokines that regulate this process and the cytoskeletal elements in fibroblasts that provide the contractile forces are poorly understood. I examined the effect of TGF-$\beta$1 on the ability of human gingival fibroblasts to contract collagen gels in vitro and on the expression of the putative fibroblast contractile marker, $\alpha$-smooth muscle actin ($\alpha$-SMA). TGF-$\beta$1 (10 ng/ml; 3 days) increased $\alpha$-SMA protein and mRNA 2-3 fold, as determined by western and northern blots and normalised for $\beta$-actin content. Western blots of cells in anchored collagen gels also showed a TGF-$\beta$1-induced increase of $\alpha$-SMA content but the effect was reduced compared to collagen-coated plastic. In floating collagen gels, TGF-$\beta$1 exerted no significant effect on $\alpha$-SMA protein. Notably, TGF-$\beta$1 increased the rate of contraction in anchored and floating collagen gels in serum-free cultures by 50% and 30% respectively but the difference was not evident in serum-containing cultures. Using an ELISA, active and latent forms of endogenous TGF-$\beta$1 were detected in all 3 models. Addition of exogenous TGF-$\beta$1 stimulated its own production. The highest levels of endogenous TGF-$\beta$1 were detected in monolayer cultures and the lowest levels in floating gels. Blocking $\alpha$2 and $\beta$1 subunits with monoclonal antibodies abolished the effect of TGF-$\beta$1 on $\alpha$-SMA expression. Collectively these data indicate that TGF-$\beta$1 may regulate wound contraction by affecting the cellular content of the contractile protein, $\alpha$-SMA and that generation of intracellular tension may regulate expression of specific cytoskeletal genes involved in cell contraction.