Transmembrane signaling in periodontal mesenchymal cells: the linkage between stimulus and response

The gingival inflammatory infiltrate in cardiac patients treated with calcium antagonists

OBJECTIVES

To analyse the periodontal inflammatory infiltrates in patients with cardiac disease, some of these patients were treated with calcium antagonists (nifedipine and diltiazem) and some were not, to compare them with a healthy control group, and to evaluate the changes in the inflammatory infiltrate after periodontal treatment.

MATERIAL AND METHODS

A "healthy group" (HG, n=12), a "cardiac group" (CG, n=12) without treatment with calcium antagonists, a "nifedipine group" (NG, n=18) and a "diltiazem group" (DG, n=13) were analysed. Biopsies were taken from a zone 2-3 mm below the upper part of the interproximal papillae 12-13 and 33-32 before causal periodontal treatment and after 1 year. Using haematoxylin-eosin staining, the plasma cells (P), lymphocytes (L), histiocytes (H) and polymorphonuclear cells (PMN) were counted. T and B lymphocytes were evaluated using the monoclonal antibodies anti-CD20 and anti-CD45RO. Statistical tests used: chi2 for study of the sample composition; ANOVA for comparison between groups; Student t-test and Wilcoxon test for comparison between visits; post-hoc test Bonferroni.

RESULTS

When the cells were compared statistically, differences were established for L at the first visit (p<0.00001) and at the last visit (p<0.02), for the B lymphocytes (first visit p<0.0021, last visit p<0.022) and for the T lymphocytes (first visit p<0.0042, last visit p<0.0021). Between the 2 visits, HG showed significant reductions for P (p<0.01), L (p<0.045) and H (p<0.033); and the NG for L (p<0.0001). Lymphocytes showed differences in the NG with respect to the B lymphocytes (p<0.008).

CONCLUSIONS

Nifedipine affects the inflammatory infiltrate with a greater number of lymphocytes (especially B) and these cells fell significantly in number after periodontal treatment.

Response of periradicular tissues to growth factors introduced into the surgical site in the root-end filling material

AIM

The objective of this study was to evaluate the healing of the periradicular tissues when exogenous growth factors were delivered to the respected root-end. The healing response was compared with that when Diaket was used as a control.

METHODOLOGY

Non-surgical root canal treatment was performed on mandibular teeth in mongrel dogs. Surgical treatment followed and included root-end resection and root-end cavity preparation. Insulin-like growth factor in combination with platelet-derived growth factor, or fibroblast growth factor alone, were then placed in the root-end preparations on a polylactic acid carrier (Atrisorb) with or without the incorporation of the carrier tetracalcium phosphate. The healing was evaluated at 60 days with regard to presence of inflammatory response, bone regeneration, periodontal ligament formation and cementum formation.

RESULTS

Osseous regeneration in the excisional would and periodontal formation were significantly greater when Diaket was used as the root-end filling material. Likewise, cementum deposition occurred significantly more frequently in the Diaket group (P < 0.05). The polylactic carrier Atrisorb remained in the surgical sites for the duration of the study.

CONCLUSIONS

The use of specific growth factors, FGF and a combination of IGF/PDGF, delivered to the prepared root end in a collagen carrier did not initiate the desired periradicular tissue response of regeneration. Diaket, as used in this study, did stimulate a periradicular tissue response compatible with regeneration.

Immunolocalization of collagenase (MMP-1) and stromelysin (MMP-3) in the gingival tissues of organ transplant patients medicated with cyclosporin

Cyclosporin-induced gingival overgrowth results from a disturbance in the homeostatic balance in the gingival tissues which is characterised by both an increase in the number of fibroblasts and in the volume of the extracellular matrix. Whilst the accumulation of the collagenous matrix is well recognised, little attention has been paid to the role of the degradative enzymes in the development of this condition in vivo. The matrix metalloproteinases MMP-1 (collagenase) and MMP-3 (stromelysin) were immunolocalized using specific polyclonal and monoclonal antisera in gingival specimens from 18 patients with drug-induced gingival overgrowth and 6 control subjects. A positive granular pattern of MMP-1 staining was seen in the vast majority of fibroblasts in specimens from drug-free controls throughout the connective tissue. This was in marked contrast to the findings in overgrown tissue, where positive cytoplasmic staining was shown by only a small number of fibroblasts. Where fibroblast staining occurred in overgrown tissue, the intracellular pattern was the same as in the drug free tissue. Positive staining was, however, largely confined to a small number of fibroblasts in the lamina propria of the outer gingival mucosa and even in this region there were areas that showed little or no fibroblast staining. This apparent cessation of collagenase production by many of the fibroblasts in gingival overgrowth supports the hypothesis that perturbation of collagenase activity is responsible for the disturbance in the homeostatic balance, which is pivotal to this condition.