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AIM: We analyse a case of idiopathic gingival overgrowth using morphological and molecular methods. As this overgrowth involves collagen accumulation in the gingival connective tissue, we measured the collagen turnover to clarify the pathogenic mechanisms potentially involved. MATERIALS AND METHODS: The patient was a 29-year-old Italian woman with enlargement of the gingivae throughout the entire mandible and maxilla. Morphological analyses were carried out on haematoxylin-eosin and Sirius red-stained paraffin-embedded gingival sections. mRNA levels of collagen type I and III, matrix metalloproteinase (MMP)-1, transforming growth factor-beta1 and lysyl hydroxylase (LH)2b were determined by RT-PCR on cultured gingival fibroblasts and compared with healthy control fibroblasts. Interstitial collagen and MMP-1 content in the supernatants were assessed, respectively, by dot blot and SDS zymography. RESULTS AND CONCLUSIONS: In Sirius red-stained sections of the patient's overgrown gingivae, interstitial collagen content was 29% higher than controls. Her gingival fibroblasts had higher collagen type I, MMP-1 and LH2b gene expression and unmodified interstitial collagen, type I protein levels in the supernatants. These findings would seem to suggest that in this case collagen accumulation in the gingival connective tissue was not associated with increased synthesis and decreased degradation. [ABSTRACT FROM AUTHOR]

J Oral Pathol Med (2004) 33: 346–53 It has been demonstrated that cyclosporin A (CyA) blocks the immune system, acts on cytoskeleton and stimulates the production of extracellular matrix (ECM) and transforming growth factor-β1 (TGF- β1). This cytokine, such as transforming growth factor-α (TGF- α), induces deposition of glycosaminoglycans (GAG), proteoglycans and collagen fibres in the ECM. In this work, we examined the effect induced by CyA, TGF- β1 and TGF- α on cultures of healthy and overgrown human gingival fibroblasts in order to evaluate the glycosaminoglycan, cytoskeletal changes and the behaviour of fibroblasts after concanavalin A (Con A) treatment. Moreover, we examined gingival biopsies by Alcian blue histochemical staining and electron transmission microscopy. Total and extracellular sulphated GAG in overgrown gingiva specimens and in derived fibroblast cultures treated with CyA and cytokines were significantly higher than controls. The action of cytokines was increased ( P ≤ 0.01) compared with CyA with a greater effect of TGF- α in comparison with TGF- β1; the electron microscopy showed ECM accumulation. The agglutinations showed the heterogeneity of fibroblast populations. Stimulation with Con A showed that the fibroblast population had cell surface heterogeneity, and could respond in a different way to both CyA and cytokine stimulus. Moreover, increased synthesis of GAG in overgrown gingiva compared with synthesis in normal fibroblasts before CyA treatment suggests a possible genetic origin of damage. As not all CyA-treated patients develop gingival overgrowth, a genetic predisposition may explain the different responses of gingival fibroblast populations. [ABSTRACT FROM AUTHOR]

The protective activity of pyridoxol L,2-pyrrolidon-5 carboxylate (metadoxine) was investigated in a rat model of carbon tetrachloride (CCL4)-induced hepatic fibrosis. After 6 weeks of CCl4 treatment, the animals developed fibrosis and inflammation of the liver while those treated with CCl4 + metadoxine had less severe lesions (P<0.05). Since in liver fibroplasia there are quantitative changes of the extracellular matrix components and almost invariably a decrease in albumin synthesis, we have also investigated by Northern blot analysis the expression of the cellular fibronectin, pro-alpha2(I)collagen and albumin genes. There were striking increases in fibronectin and pro-alpha2(I)collagen mRNA contents in the livers of CCL4-treated animals and these enhancements were less evident in the metadoxine-treated rats. In contrast, albumin mRNA levels, almost identical in control and metadoxine-treated rats, were lower in the CCl4-treated animals. These data suggest that metadoxine might slow the development of CCl4-mediated liver fibrosis. [ABSTRACT FROM AUTHOR]

Two letters to the editor are presented in response to articles in previous issues including "Gene Expression Profile of Extracellular Matrix of Tendons in Cerebral Palsy" and "Transcortical Sensory Aphasia in a Child With Subacute Sclerosing Panencephalitis."

Aim: FK506 is an immunosuppressive agent that, unlike cyclosporin A (CsA), does not induce gingival overgrowth (GO). CsA-induced GO is caused by quantitative modifications of the extracellular matrix components, particularly collagen (COL). Up to now, clinical trials have only investigated FK506 in relation with GO, so we aimed at analysing the effect of FK506 on COL turnover using a molecular approach, to evaluate the expression of genes and proteins related to this process., Materials and Methods: Human gingival fibroblasts were incubated with FK506 or its vehicle (VH) for 24, 48 and 72 h. COL type I (COL-I), matrix metalloproteinases (MMP)-1 and 2, tissue inhibitor of MMP (TIMP)-1 and transforming growth factor (TGF)-beta1 mRNA were assayed by Reverse transcriptase polymerase chain reaction; COL-I protein levels were determined by dot blot, MMP-1 and MMP-2 activity by zymography., Results: Fibroblast proliferation decreased 48 and 72 h after treatment. COL-I gene and protein expression, TGF-beta1 and TIMP-1 mRNA levels were not significantly affected, whereas MMP-1 gene and protein expression and MMP-2 mRNA levels rose significantly in treated fibroblasts compared with VH., Conclusions: These findings suggest that increased MMP-1 gene and protein expression may be important for regulating COL-I homeostasis in the gingival connective compartment of FK506-immunosuppressed subjects., ((c) Blackwell Munksgaard, 2005.)