Cyclosporine-induced gingival overgrowth: an ultrastructural stereologic study

Oro-Dental Health and Primary Nephrotic Syndrome among Vietnamese Children

Primary nephrotic syndrome (PNS) is common in children, affecting the soft and hard tissues of the oral cavity. This study aimed to investigate the percentage of dental caries, gingivitis, hypertrophic gingivitis, and developmental defects of enamel (DDE) in children with PNS. The association of PNS with these diseases and oral care behavior was also assessed. A total of 407 children with PNS and 407 age- and gender-matched controls were recruited. PNS was diagnosed based on blood and urinary tests. The Simplified Oral Hygiene Index (OHI-S), the Gingival Index (GI), the Gingival Overgrowth Index (GOI), the Decayed, Missing, and Filled Teeth Index (dmft/DMFT), and DDE were collected. The PNS patients showed significantly higher scores of OHI-S, GI, and dmft, and higher proportions of dental caries and DDE than those of the controls (p < 0.001). It is necessary to establish a periodic dental protocol for PNS patients to improve their oral health status.

Nifedipine and Cyclosporin Affect Fibroblast Calcium and Gingiva

It has been stated that cyclosporin and nifedipine produce gingival overgrowth. However, the specific pathogenic mechanism remains uncertain. We used an experimental rat model to test the hypothesis that changes in collagen metabolism and numbers of gingival blood vessels are not mediated by intracellular calcium concentration (ratiometric Fura-2 AM measurement) in gingival fibroblasts. In the cyclosporin group, both width (364.2 ± 67.5 μm) and microvessel density (number of vessels/mm2, stained with anti-CD34 antibody) (41.6 ± 5.1) of gingiva were statistically different when compared with those in the control group (width = 184.3 ± 35.2 μm, microvessel density = 19.6 ± 2.4). The nifedipine group showed the highest content of collagen (proportion of total stroma occupied by collagen, stained with Picro-Mallory) (nifedipine group = 66.3 ± 9.4, cyclosporin group = 55.2 ± 7.9, control group = 30.1 ± 10.2). Freshly cultured fibroblasts from the cyclosporin group exhibited higher ratiometric values of fluorescence than did both the control and nifedipine groups (p = 0.03). Our results support the hypothesis that changes in gingival collagen metabolism are not mediated by calcium intracellular oscillations.

The Relationship between Proliferating Cell Nuclear Antigen Expression and Histomorphometrical Alterations in Cyclosporin A-Induced Gingival Overgrowth in Rats

The aim of this study was to investigate the relationship between Proliferating Cell Nuclear Antigen (PCNA) expression and histomorphometrical alterations in cyclosporin A (CsA)-induced gingival overgrowth with or without microbial dental plaque accumulation. Forty male Wistar rats were equally divided into 4 groups; Group I (control); Group II (CsA); Group III (ligature); Group IV (ligature and CsA). After 8 weeks of experimental period, rats were subsequently decapitated and mandibular molars were dissected. Gingival overgrowth was determined by measuring depth of the gingival sulcus, then the mandible were decalcified and serial sections were obtained for histomorphometric and immunohistochemical analysis. Histomorphometric analysis included the measurement of epithelial thickness; immunohistochemical analysis included the assessment of PCNA expression in the oral and sulcular epithelium of buccal and lingual gingiva. Epithelial thickness and PCNA expression were significantly increased in buccal oral epithelium of Group II ( p < 0.05) and in all regions in Group IV ( p < 0.05) compared to control group. Also gingival overgrowth was more prominent in Group IV in comparison to Group II. These results indicate that CsA-induced gingival alterations are closely accociated with increased epithelial proliferative activity, and dental plaque accumulation seems not to be an essential but to be an aggrevating factor for the progression of the lesion.

Role of discoidin domain receptor 1 in dysregulation of collagen remodeling by cyclosporin A

The anti-transplant rejection drug cyclosporin A (CsA) causes loss of collagen homeostasis in rapidly remodeling connective tissues, such as human gingiva. As a result of CsA treatment, collagen degradation by fibroblasts is inhibited, which leads to a net increase of tissue collagen and gingival overgrowth. Since fibrillar collagen is the primary ligand for the discoidin domain receptor 1 (DDR1), we hypothesized that CsA perturbs DDR1-associated functions that affect collagen homeostasis. For these experiments, human fibroblasts obtained from gingival explants or mouse 3T3 fibroblasts (wild type, over-expressing DDR1 or DDR1 knockdown) or mouse GD25 cells (expressing DDR1 but null for β1 integrin), were treated with vehicle (dimethyl sulfoxide) or with CsA. The effect of CsA on cell binding to collagen was examined by flow cytometry; cell-mediated collagen remodeling was analyzed with contraction, compaction and migration assays. We found that CsA inhibited cell binding to collagen, internalization of collagen, contraction of collagen gels and cell migration over collagen in a DDR1-dependent manner. CsA also enhanced collagen compaction around cell extensions. Treatment with CsA strongly reduced surface levels of β1 integrins in wild type and DDR1 over-expressing 3T3 cells but did not affect β1 integrin activation or focal adhesion formation. We conclude that CsA inhibition of collagen remodeling is mediated through its effects on both DDR1 and cell surface levels of the β1 integrin.

Always cleave up your mess: targeting collagen degradation to treat tissue fibrosis

Pulmonary fibrosis is a vexing clinical problem with no proven therapeutic options. In the normal lung there is continuous collagen synthesis and collagen degradation, and these two processes are precisely balanced to maintain normal tissue architecture. With lung injury there is an increase in the rate of both collagen production and collagen degradation. The increase in collagen degradation is critical in preventing the formation of permanent scar tissue each time the lung is exposed to injury. In pulmonary fibrosis, collagen degradation does not keep pace with collagen production, resulting in extracellular accumulation of fibrillar collagen. Collagen degradation occurs through both extracellular and intracellular pathways. The extracellular pathway involves cleavage of collagen fibrils by proteolytic enzyme including the metalloproteinases. The less-well-described intracellular pathway involves binding and uptake of collagen fragments by fibroblasts and macrophages for lysosomal degradation. The relationship between these two pathways and their relevance to the development of fibrosis is complex. Fibrosis in the lung, liver, and skin has been associated with an impaired degradative environment. Much of the current scientific effort in fibrosis is focused on understanding the pathways that regulate increased collagen production. However, recent reports suggest an important role for collagen turnover and degradation in regulating the severity of tissue fibrosis. The objective of this review is to evaluate the roles of the extracellular and intracellular collagen degradation pathways in the development of fibrosis and to examine whether pulmonary fibrosis can be viewed as a disease of impaired matrix degradation rather than a disease of increased matrix production.

Matrix metalloproteinases, tissue inhibitors of matrix metalloproteinases, and inflammation in cyclosporine A-induced gingival enlargement: a pilot in vitro study using a three-dimensional model of the human oral mucosa

BACKGROUND

It has been suggested that cyclosporine A (CsA) induces gingival enlargement by promoting an increase in the gingival extracellular matrix (ECM). Nonetheless, the variable occurrence of CsA-induced gingival enlargement in patients receiving this medication indicates a multifactorial pathogenesis. Clinical observations suggest that local inflammation is associated with the development and severity of CsA-induced gingival enlargement. Therefore, the purpose of this study is to investigate the effects of CsA and inflammation on the production of ECM homeostatic mediators.

METHODS

The effects of CsA and inflammation (as assessed using interleukin [IL]-1β) on the secretion of mediators involved in ECM homeostasis were determined using fibroblast monolayers and three-dimensional (3D) models of the human oral mucosa. Fibroblast monolayers and 3D cultures were treated with CsA alone or in combination with IL-1β for up to 72 hours, and the secretion of matrix metalloproteinases (MMPs) 1, 2, 3, 8, 9, 10, and 13 and tissue inhibitors of MMPs (TIMPs) 1, 2, and 4 into the culture medium was assessed using enzyme-linked immunoassay-based antibody arrays.

RESULTS

Fibroblast monolayers responded to CsA with no changes in the secretion of ECM mediators. Conversely, 3D cultures responded to CsA treatment with a reduction in MMP-10 secretion. IL-1β alone triggered higher secretory levels of MMPs in both fibroblast monolayers (MMP-3 and MMP-10) and 3D cultures (MMP-9 and MMP-10). Importantly, fibroblast monolayers and 3D cultures treated with a combination of IL-1β and CsA showed a decrease in the MMP-1/TIMP-1 ratio.

CONCLUSIONS

These data support the hypothesis that inflammation may alter the pathogenesis of CsA-induced gingival enlargement by promoting a synergistic decrease in the MMP-1/TIMP-1 ratio.

TGF-β1 gene polymorphism in renal transplant patients with and without gingival overgrowth

BACKGROUND

The incidence of gingival overgrowth among renal transplant patients treated with cyclosporine A ranges from 13% to 84.6%, and the overgrowth is not only esthetic but also a medical problem. We studied the determination of association between TGF-β1 (TGFB1) gene polymorphism and gingival overgrowth in kidney transplant patients medicated with cyclosporin A.

METHODS

Eighty-four kidney transplant patients with gingival overgrowth and 140 control transplant patients without overgrowth were enrolled into the case control study. TGFB1 polymorphism was determined using the PCR-RFLP assay for +869T > C in codon 10 and +915G > C in codon 25 as well as TaqMan real-time PCR assays for promoter -800G>A and -509C > T SNPs.

RESULTS

In kidney transplant patients suffering from gingival overgrowth, mean score of gingival overgrowth was 1.38 ± 0.60, whereas in control subjects it was 0.0. The patients with gingival overgrowth were characterized by similar distribution of TGFB1 genotypes and allele in comparison to subjects without gingival overgrowth. Among 16 potentially possible haplotypes of TGFB1 gene, only four were observed in the studied sample of kidney transplant patients: G_C_T_G, G_T_C_G, G_C_C_C, and A_C_T_G, with similar frequency in patients with and without gingival overgrowth.

CONCLUSION

No association between the TGFB1 gene polymorphism and gingival overgrowth was revealed in kidney transplant patients administered cyclosporine A.

Mfge8 diminishes the severity of tissue fibrosis in mice by binding and targeting collagen for uptake by macrophages

Milk fat globule epidermal growth factor 8 (Mfge8) is a soluble glycoprotein known to regulate inflammation and immunity by mediating apoptotic cell clearance. Since fibrosis can occur as a result of exaggerated apoptosis and inflammation, we set out to investigate the hypothesis that Mfge8 might negatively regulate tissue fibrosis. We report here that Mfge8 does decrease the severity of tissue fibrosis in a mouse model of pulmonary fibrosis; however, it does so not through effects on inflammation and apoptotic cell clearance, but by binding and targeting collagen for cellular uptake through its discoidin domains. Initial analysis revealed that Mfge8-/- mice exhibited enhanced pulmonary fibrosis after bleomycin-induced lung injury. However, they did not have increased inflammation or impaired apoptotic cell clearance after lung injury compared with Mfge8+/+ mice; rather, they had a defect in collagen turnover. Further experiments indicated that Mfge8 directly bound collagen and that Mfge8-/- macrophages exhibited defective collagen uptake that could be rescued by recombinant Mfge8 containing at least one discoidin domain. These data demonstrate a critical role for Mfge8 in decreasing the severity of murine tissue fibrosis by facilitating the removal of accumulated collagen.

Effects of cyclosporin, phenytoin, and nifedipine on the synthesis and degradation of gingival collagen in tufted capuchin monkeys (Cebus apella): histochemical and MMP-1 and -2 and collagen I gene expression analyses

BACKGROUND

The purpose of this experimental study was to evaluate the collagen fiber distribution histologically after phenytoin, cyclosporin, or nifedipine therapy and to correlate it with collagen I and matrix metalloproteinase (MMP)-1 and -2 gene expression levels.

METHODS

Gingival samples from the canine area were obtained from 12 male monkeys (Cebus apella). The mesial part of each sample was assessed by reverse transcription-polymerase chain reaction, whereas the distal part was processed histologically for picrosirius red and hematoxylin and eosin stainings, as well as for collagen IV immunostaining. One week after the first biopsy, the animals were assigned to three groups that received daily oral dosages of cyclosporin, phenytoin, or nifedipine for 120 days. Additional gingival samples were obtained on days 52 and 120 of treatment from two animals from each group on the opposite sides from the first biopsies.

RESULTS

Picrosirius red staining showed a predominance of mature collagen fibers in the control group. Conversely, there was an enlargement of areas occupied by immature collagen fibers in all groups at days 52 and 120, which was not uniform over each section. There was a general trend to lower levels of MMP-1 gene expression on day 52 and increased levels on day 120. Phenytoin led to increased levels of MMP-2 and collagen I gene expression on day 120, whereas the opposite was observed in the nifedipine group.

CONCLUSION

Cyclosporin, phenytoin, and nifedipine led to phased and drug-related gene expression patterns, resulting in impaired collagen metabolism, despite the lack of prominent clinical signs.

Drug-induced gingival overgrowth--a review

Drug-induced gingival overgrowth is a side effect associated with 3 types of drugs: anticonvulsants (phenytoin), immunosuppressive agents (cyclosporine A), and various calcium channel blockers for cardiovascular diseases. Gingival overgrowth is characterized by the accumulation of extracellular matrix in gingival connective tissues, particularly collagenous components with various degrees of inflammation. Although the mechanisms of these disorders have not been elucidated, recent studies suggest that these disorders seem to be induced by the disruption of homeostasis of collagen synthesis and degradation in gingival connective tissue, predominantly through the inhibition of collagen phagocytosis of gingival fibroblasts. The integrins are a large family of heterodimeric transmembrane receptors for extracellular matrix molecules. alpha2beta1 integrin serves as a specific receptor for type I collagen on fibroblasts, and alpha2 integrin has been shown to play a crucial role in collagen phagocytosis. Actin filaments, which are assembled from monomers and oligomers, are involved in collagen internalization after binding to integrins. Furthermore, the implication of intracellular calcium in the regulation of integrin-mediated binding activity and gelsolin activity, known as a calcium-dependent actin-severing protein, is also described. In this review, we focus on collagen metabolism in drug-induced gingival overgrowth, focusing on the regulation of collagen phagocytosis in fibroblasts.

Trial of metronidazole vs. azithromycin for treatment of cyclosporine-induced gingival overgrowth

Gingival overgrowth usually characterized by increased cellular growth of gingival fibroblasts appears to be multifactorial. In patients receiving CyA for more than 3 months, the incidence can approach 70% and can be attributed to pharmaceutical immunosuppression. Case reports have reported regression of overgrowth with both metronidazole and azithromycin. The goal of this study was to determine the efficacy of metronidazole and azithromycin in reducing CyA-induced gingival overgrowth. Twenty-five patients were included in this double-blinded randomized study. All patients were receiving CyA as medically indicated and diagnosed with gingival overgrowth by a dentist. Patients were randomized to receive either 5-days of azithromycin or 7-days of metronidazole given at baseline only. The extent of gingival overgrowth was measured at 0, 2, 4, 6, 12, and 24 wk. Fourteen patients at CCF and 11 patients at CCHMC were studied. Repeated measures anova was performed to assess differences within and between groups. Gingival overgrowth at baseline was not statistically different between groups. The mean degree of gingival overgrowth after treatment was different across all time intervals (p = 0.0049) showing azithromycin to be more effective than metronidazole. Therapy with azithromycin offers an effective alternative to the management of CyA-induced gingival overgrowth.

Gene Expression of Extracellular Matrix Proteoglycans in Human Cyclosporin-Induced Gingival Overgrowth

BACKGROUND

Gingival overgrowth is one of the side effects associated with the systemic use of cyclosporin A (CsA). In vitro studies on the extracellular matrix of gingival tissues have demonstrated an altered composition, particularly an accumulation of proteoglycans and collagen. We investigated the gene expression of extracellular matrix proteoglycans in CsA-induced gingival tissue alterations.

METHODS

mRNA expression of the proteoglycans perlecan, decorin, biglycan, and versican was analyzed by reverse transcription polymerase chain reaction (RT-PCR) in gingival samples obtained from 12 individuals, six with CsA-induced gingival overgrowth (CsA group) and six with a normal gingiva (control group). The RT-PCR products were subjected to 1% agarose gel electrophoresis containing ethidium bromide and analyzed qualitatively and semiquantitatively by densitometry. Density values were normalized by determining the expression of the housekeeping gene beta-actin in the same sample. Groups were compared by the Student's t test.

RESULTS

Perlecan expression showed a marked increase (54%) in the CsA group compared to the control group (P < 0.01), while no significant differences were observed for the other proteoglycans.

CONCLUSION

CsA-induced gingival overgrowth seems to be associated with increased expression of perlecan, a typical basement membrane proteoglycan, but not decorin, biglycan, or versican.

Decreased expression of alpha2 integrin in fibroblasts isolated from cyclosporin A- induced gingival overgrowth in rats

OBJECTIVES

Cyclosporin A (CsA), an immunosuppressive agent, induces fibrous gingival overgrowth through reduction of collagen phagocytosis by fibroblasts. Distinct receptors are involved in the binding of collagen to fibroblasts in collagen phagocytosis, and alpha2beta1 integrin serves as a specific receptor for type I collagen on fibroblasts. To elucidate the role of alpha2beta1 integrin in CsA-induced gingival overgrowth, we investigated collagen phagocytosis and alpha2beta1 integrin expression in rat gingival fibroblasts.

MATERIALS AND METHODS

Fibroblats were isolated from gingiva of rats fed a powdered diet containing or lacking CsA for 30 d. Flow cytometric analysis were performed to measure the collagen phagocytosis and the alpha2 integrin expression in fibroblasts. Furthermore, total RNAs were isolated from fibroblasts, and the reverse transcriptase-polymerase chain reaction was employed to investigate the mRNA levels of alpha2 integrin.

RESULTS

In vitro collagen phagocytosis assay revealed that CsA-treated and control fibroblasts contained a mean of 13.5% and 36.1% phagocytic cells, respectively. CsA-treated fibroblasts had 28% lower expression of alpha2 integrin than that of control. and mRNA expression of alpha2 integrin in CsA-treated fibroblasts was apparently lower than in the controls, but the mRNA expression of beta1 integrin was not affected.

CONCLUSION

These findings suggest that one etiological factor of gingival overgrowth may be inhibition of collagen phagocytosis by reducing alpha2 integrin expression in gingival fibroblasts.

Combined effects of cyclosporin and nifedipine on gingival overgrowth in rats is not age dependent

BACKGROUND

Cyclosporin A and nifedipine cause gingival overgrowth in rat, and the combined use of these drugs increases the overgrowth severity.

OBJECTIVE

The purpose of this study was to compare gingival overgrowth of rats of differents ages treated with cyclosporin A and nifedipine alone or given concurrently.

MATERIALS AND METHODS

Rats 15, 30, 60 and 90 d old were treated with 10 mg/kg body weight of cyclosporin A and/or 50 mg/kg body weight of nifedipine in the chow.

RESULTS

Young rats showed evident gingival overgrowth with nifedipine, cyclosporin A, and cyclosporin A and nifedipine given concurrently. Adult rats did not show significant gingival alterations when treated with cyclosporin A and nifedipine alone. Nevertheless evident gingival overgrowth with alterations of the epithelium and connective tissue were observed when treated simultaneously with cyclosporin A and nifedipine.

CONCLUSION

These results suggest that the combined effects of cyclosporin A and nifedipine on gingival overgrowth in rat is not age dependent.

Gastrointestinal side effects of drugs

Drugs can have adverse effects on any part of the gastrointestinal (GI) tract from mouth to colon. It is essential that a detailed and accurate drug history is taken in patients presenting with GI complaints. Many drug-induced effects will regress or heal on cessation of treatment. NSAIDs are usually associated with gastric and duodenal ulcers but are also recognised to cause lichen planus in the mouth, oesophageal inflammation and strictures, and small bowel and colonic ulcers and strictures. A newer class of anti-inflammatory drugs, the cyclooxygenase-2 (COX-2)-selective inhibitors, have been developed and have a more favourable GI safety profile than standard NSAIDs. Acute diarrhoea, relapse of inflammatory bowel disease (IBD), microscopic colitis and acute pancreatitis are also induced by ingestion of standard NSAIDs. The calcium antagonists, phenytoin and cyclosporin, induce gum hyperplasia, particularly in patients with poor oral hygiene. Alendronate, a bisphosphonate, has been associated with development of oesophageal ulcers, and specific recommendations are now given to reduce this complication. Of the many different forms of colitis associated with drug ingestion, the most frequent is pseudomembranous colitis. This is a complication of antibiotics and is caused by the toxin produced by Clostridium difficile. Many drugs have been associated with the development of acute pancreatitis, although a definite cause and effect relationship has been shown for only a few drugs. These include didanosine, furosomide, corticosteroids, azathioprine and sodium valproate.

Mechanisms and management of gingival overgrowth in paediatric transplant recipients: a review

Increasing numbers of children are receiving solid organ transplants namely kidney, liver, heart and lung. Patient survival rates following such transplants are essentially good with much of the success attributable to the development of Cyclosporine A (CyA), an immunosuppressive drug, that minimizes organ rejection. However the gingival overgrowth (GO) associated with the use of CyA is not only disfiguring but in paediatric recipients, may interfere with normal oral development and function.

OBJECTIVE

The aim of this review is to summarize current knowledge concerning the aetiology, pathogenesis and management of gingival overgrowth.

METHODS

Literature pertaining to gingival overgrowth is reviewed with particular reference to the paediatric population. Emphasis is placed on summarizing the evidence pertaining to the effectiveness of intervention.

CONCLUSION

CyA undoubtedly causes gingival overgrowth, the effects and levels of which appears to be more severe in younger patients. There is conflicting evidence as to the effectiveness of oral hygiene regimes, antibiotics and surgery in reducing overgrowth. The introduction of an alternative immunosuppressive agent (Tacrolimus) offers potential as it does not appear to cause overgrowth, although research to date is limited by the small sample size of many of the studies. This is an area in which multicentre studies would be of great value.

Oral manifestations of drug therapy

The oral cavity may be the target organ for a number of diverse abnormalities that develop from side effects of medications. Because of the widespread and increasing use of prescription, over-the-counter, and herbal remedies, it is becoming increasingly likely that the dentist will encounter soft tissue or dental pathologies that represent a complication of a therapeutic agent. The more common abnormalities that may occur include gingival hyperplasia, tooth discoloration, candidiasis, chemical injuries, and altered taste perception. The dental practitioner is often the primary health care provider who can recognize, diagnose, treat, and/or prevent these conditions.

Cytomegalovirus and cyclosporin-induced gingival overgrowth in children with liver grafts

OBJECTIVE

To determine whether cytomegalovirus (CMV) is associated with gingival overgrowth in paediatric liver graft recipients treated with cyclosporin.

STUDY DESIGN

Thirty-four children, 25 of whom were under 5 years of age, who had undergone liver transplantation, were examined. An Index of Severity of Gingival Overgrowth was used to measure the prevalence and severity of the gingival overgrowth. The trough cyclosporin level was recorded and the CMV status of the patient matched to the dental findings. The association between the severity of gingival overgrowth and CMV infection was examined using the contingency coefficient. An anova was used to assess the association between the circulating trough cyclosporin concentration and the severity of gingival overgrowth. Pearson's Product Moment Correlation Coefficient was used to examine the association between the duration of exposure to cyclosporin and the severity of gingival overgrowth.

RESULTS

There was a significant inverse association between the duration of exposure to cyclosporin and the severity of gingival overgrowth. There was no relationship between the trough cyclosporin concentration and the severity of gingival overgrowth. There was no association between CMV and gingival overgrowth.

CONCLUSION

Gingival overgrowth was related to the duration of cyclosporin therapy but was neither more prevalent nor more severe in subjects who were CMV seropositive.

Does nifedipine aggravate cyclosporin--induced gingival overgrowth? An experiment in rats

BACKGROUND

Nifedipine (NIF) may aggravate cyclosporin A (CsA)-induced gingival overgrowth because the potentiated gingival overgrowth has been observed in the patients treated with CsA and NIF. The purpose of this study was to evaluate whether NIF could aggravate the CsA-induced gingival overgrowth in a rat model.

METHODS

Ninety male Sprague-Dawley rats were divided into 6 groups: the first group received 8 mg/kg of CsA daily by gastric feeding for 6 weeks; the second and third groups received NIF daily at a dosage of 10 or 50 mg/kg; the fourth and fifth groups received CsA (8 mg/kg) and NIF (10 or 50 mg/kg); and the sixth group received solvents as a negative control. Gingival dimensions (including bucco-lingual depth, mesio-distal width, and vertical height) were assessed bi-weekly from impressed stone models of the mandibular incisal region. At the end of the experiment, the animals were sacrificed. Following histopathological procedures, serial horizontal sections were obtained at the base of the central incisal papilla. Two tissue levels were selected for histometric analysis. Level 1 was defined as the point where the lingual gingiva embraced the bucco-lingual midpoint of the roots and the level 2 as the point where the lingual gingiva at the enamel-dentinal junction approximated the bucco-proximal angle of the roots. The bucco-lingual depth and the mesio-distal width of the papilla were recorded on 5 consecutive sections at the 2 levels, respectively.

RESULTS

At the 6-week observations, the gingival dimensions (including the depth, width, and height) significantly increased after CsA therapy and the increasing treatment duration; however, only the mesio-distal width increased after NIF therapy. For NIF therapy alone, a positive linear relation was noted by increased NIF treatment dosages in all gingival dimensions at week 6. But, this relationship was not found in the combined therapies. By histometry, tissue dimensions increased following single drug therapy, either CsA or NIF, at both levels. In animals with the combined therapies, the tissue dimensions decreased if the animals received 10 mg NIF, while they rebounded to control levels with the 50 mg dosage. A dose-dependent positive pattern by NIF was noted in tissue dimensions, but the pattern did not occur in animals that received combined therapy.

CONCLUSIONS

The gingival dimensions increased after CsA or NIF therapy, although they were more prevalent with CsA. But the augmenting pattern in gingival morphology observed with CsA therapy decreased when the animals received additional NIF. Therefore, we question whether NIF is a critical factor in aggravating the CsA-induced gingival overgrowth.

Cyclosporin A decreases the degradation of type I collagen in rat gingival overgrowth

Cyclosporin A (CsA) is used as an immunosuppressive agent and its prominent side effect is the induction of fibrous gingival overgrowth. The purpose of this study was to investigate the effect of CsA on the type I collagen metabolism in the gingiva of rats fed a powdered diet either containing or lacking CsA. Immunohistochemical analysis revealed that type I collagen was more prevalent in the connective tissue of CsA-treated gingiva than in those of control rats on days 15, 30, and 55 after the start of feeding. Total RNAs were isolated from mandibular molar gingiva on days 0, 3, 8, 15, 30, and 55. Quantitative analysis of mRNA by reverse transcriptase-polymerase chain reaction revealed that the CsA-treated groups showed a gradual decrease in expression of type I collagen and collagenase mRNAs, 0.4% and 18.0% on day 55 compared with those on day 0, respectively. In the control groups, type I collagen and collagenase mRNAs also decreased to 19.7% and 63.0%, respectively, however, both mRNA expressions were significantly lower in the CsA-treated group than in the controls. An electron microscopic analysis of fibroblasts was performed to count the number of cells with collagen fibrils in the cytoplasm, a marker of phagocytosis of collagen by fibroblasts. The collagen fibrils were detected in 4.7% +/- 2.7% and 24.3% +/- 13.7% of fibroblasts in the overgrown gingiva treated with CsA rat for 8 days and 30 days, but in 57.0% +/- 5.3% and 81.3% +/- 9.2% of fibroblasts in the each control group gingiva, respectively. Furthermore, in vitro analysis was performed to measure the phagocytosis of cultured fibroblasts by flow cytometry using collagen-coated latex beads. Fibroblasts isolated from CsA-treated gingiva on day 8 and day 30 contained 5.7% +/- 0.6% and 9.9% +/- 1.5% phagocytic cells, whereas control fibroblasts contained 50.3% +/- 5.5% and 33.3% +/- 4.9% phagocytic cells, respectively. The inhibition rate of phagocytic activity was similar between in vivo and in vitro assays. These findings suggest that the decrease of the collagen degradation due to the lower phagocytosis and the lower collagenase mRNA expression are closely associated with the increase of type I collagen accumulation in CsA-treated rat gingiva.

Deficiency in collagen and fibronectin phagocytosis by human buccal mucosa fibroblasts in vitro as a possible mechanism for oral submucous fibrosis

Oral submucous fibrosis (OSF), a chronic oral mucosal condition commonly found in south Asians, is a disorder characterized by a quantitative as well as a qualitative alteration of collagen deposition within the subepithelial layer of the oral mucosa. Since degradation of collagen by fibroblast phagocytosis is an important pathway for physiological remodelling of soft connective tissues, we have investigated phagocytosis of collagen- and fibronectin-coated latex beads by fibroblast cultures with an in vitro model system. Coated fluorescent latex beads were incubated with human oral mucosa fibroblasts and the fluorescence associated with internalized beads was measured by flow cytometry. Cells from normal tissues that had been incubated with beads for 16 h contained a mean of 75% collagen phagocytic cells and 70% fibronectin phagocytic cells; however, about 15% and 10% of phagocytic cells individually contained more than twice the mean number of beads per cell. In contrast, cells from OSF tissues exhibited a 40% reduction of the proportions of collagen phagocytic cells (mean=35%) and a 48% decrease of the proportions of fibronectin phagocytic cells (mean=22%), none of the cells having a high number of beads as compared to normal fibroblasts. OSF lesions appear to contain fibroblasts with marked deficiencies in collagen and fibronectin phagocytosis. To investigate if inhibition of phagocytosis could be demonstrated in vitro, normal fibroblast cultures were incubated with areca nut alkaloids (arecoline, arecaidine). The cultures had a dose-dependent reduction in the proportions of phagocytic cells. On the other hand, corticosteroid used in the treatment of OSF exhibited a dose-dependent enhancement in the proportion of phagocytic cells. Therefore, our hypothesis for OSF, although oversimplified, is that betel nut alkaloids (arecoline, arecaidine) inhibit fibroblast phagocytosis and this provides a mechanism for the development of OSF. The benefit of a local intralesional injection of corticosteroid is also possibly, at least in part, through an enhancement of fibroblast collagen phagocytosis.

Medically induced gingival hyperplasia

Gingival hyperplasia or gingival overgrowth is a common occurrence in patients taking phenytoin, cyclosporine, or calcium channel blockers. Speech, mastication, tooth eruption, and aesthetics may be altered. Controlling the inflammatory component through an appropriate oral hygiene program may benefit the patient by limiting the severity of the gingival overgrowth. In patients in whom gingival overgrowth is present or may be anticipated, recognition of this condition and referral to a general dentist or periodontist are appropriate steps to management. The physician's awareness of the potential for development of overgrowth and the dental practitioner's role in attempting to prevent or minimize this problem are important aspects. In this article, we discuss the medications associated with gingival hyperplasia and describe appropriate recommendations.

Nifedipine-induced gingival overgrowth in rats: brief review and experimental study

The first case report of gingival overgrowth induced by nifedipine (NIF), a calcium-beta blocker, was in 1984. However, the association between gingival alterations and the drug therapy of sodium diphenyl hydantoinate was initially described in 1939. The purpose of the experimental study was to examine the effect of NIF on gingival morphology in an animal model. Forty-five male Sprague-Dawley rats were randomly divided into 3 groups. Animals in each group daily received NIF in dimethyl sulfoxide by gastric feeding at a dosage of 0 (control), 30, or 50 mg/kg body weight for 9 weeks. Gingival gross morphology was assessed tri-weekly from stone models obtained from the mandibular incisal region. Animals were sacrificed at the end of study and tissue blocks were processed for histopathologic and histometric evaluation. Histometric analysis was performed at 5 selected tissue levels. Macro- and microscopic significantly increased gingival dimensions were demonstrated in NIF-treated animals compared to control. Although a fibrovascular tissue was observed in the tooth-gingiva interface for both NIF-treated and control animals, it was thicker and appeared earlier in NIF-treated animals. The results of the present study suggest that gingival overgrowth can be induced by NIF in rats and that the gingival overgrowth appears dose dependent.

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.

Medication induced gingival overgrowth

A number of idiopathic, pathological and pharmacological reactions may result in an overgrowth of the gingiva. This review concentrates on those overgrowths associated with various pharmacological agents. The pharmaco-kinetics and side effects of each drug associated with gingival overgrowth are discussed along with the clinical and histological features and treatment. By examining the possible pathogeneses for these overgrowths we propose a unifying hypothesis for the causation based around inhibition of apoptosis and decreased collagenase activity modulated by cytoplasmic calcium.

Reduction of cyclosporine-induced gingival overgrowth following a change to tacrolimus. A case history involving a liver transplant patient

During immunosuppression with cyclosporine, gingival overgrowth, a minor secondary effect, may appear in the first weeks of treatment. In certain cases it may affect the function and/or esthetic appearance in a manner intolerable to the patient. A new immunnosuppressive molecule, tacrolimus, presently used as a treatment of second choice to control acute corticoresistant rejection, may bring oral comfort to these patients, since it reduces gingival overgrowth to negligible levels.

Pre-transplant gingival hyperplasia predicts severe cyclosporin-induced gingival overgrowth in renal transplant patients

The relationship between the pre-transplant periodontal status and the development of post-transplant gingival overgrowth was investigated in a longitudinal study. The periodontal condition of 35 patients was examined on 2 occasions while they were on the transplant waiting list and then at 4-6, 10-12, 16 and 20 weeks post-transplant. At each visit the plaque index, the bleeding index and a pocket index (CPITN) were measured. Dental impressions were taken of the pre- and post-transplant gingival condition and used to make stone models which were used to score the gingival overgrowth index (GOI). The patients divided into 3 distinct groups having severe (n=13), mild (n=16) or no post-transplant gingival overgrowth (n=6). Only 1 of the patients had taken cyclosporin prior to inclusion into the study. All the patients who developed severe overgrowth had evidence of gingival hyperplasia before the transplant. There was no difference in the serum cyclosporin levels between the three groups (chi2<2.28, p>0.319). Furthermore, there was no statistical difference for any of the periodontal indices. This study indicates that the hyperplastic gingival inflammatory response of some individuals appears to be potentiated by cyclosporin resulting in severe post-transplant overgrowth. In other patients the same reaction may allow the fibroblastic activity to occur to an extent where it produces a mild clinically apparent overgrowth.

Deregulation of collagen phagocytosis in aging human fibroblasts: effects of integrin expression and cell cycle

Intracellular degradation of collagen by phagocytosis in fibroblasts is essential for physiological remodeling of the extracellular matrix in a wide variety of connective tissues but imbalances between degradation and synthesis can lead to loss of tissue collagen. As aging is associated with loss of dermal and periodontal collagen and with increased lysomomal enzyme content in fibroblasts, we examined the regulation of collagen phagocytosis by integrin expression and the cell cycle in an in vitro fibroblast aging model. Two different fibroblast lines (CL1; CL2) at the fourth subculture were passaged up to replicative senescence to model aging processes in vitro. Cells were incubated with collagen-coated or BSA-coated green fluorescent beads for 3 h to assess alpha 2 beta 1-integrin-mediated or nonspecific phagocytosis, respectively. Single-cell suspensions were stained with DAPI and sulforhodamine 101 to separate cycling G1 and noncycling G0 cells. Staining for alpha 2-integrin, bead internalization, and bivariate analyses of DNA/protein content were measured by three-color flow cytometry. Serum deprivation was used to induce increases in the proportion of G0 cells. For G1 cells, the proportion of collagen phagocytic cells was > 50% for all passages and collagen beads were internalized > 5-fold more frequently than BSA beads. In contrast, G0 cells with diploid DNA content but low protein content exhibited greatly reduced phagocytic capacity (< 10% of cells internalized collagen or BSA beads), the number of beads per cells was 4-fold less, and alpha 2 integrin expression was very low compared to G1 cells. The proportion of collagen phagocytic cells and the proportion of alpha 2-integrin-positive cells increased with transit through the cell cycle. At higher passage numbers mean cell volume and cytoplasmic granularity were reduced approximately 30% but at replicative senescence cells with large surface area and subdiploid DNA predominated. The proportion of collagen and BSA phagocytic G1 cells increased 1.5- and 5-fold, respectively, and the number of beads per cell increased < 3-fold. However, surface alpha 2-integrin staining remained unchanged. These data indicate that the collagen and nonspecific internalization pathways were greatly unregulated, independent of cell cycle phase, and that cellular aging in vitro strongly influences the specificity and rate of phagocytic processes in fibroblasts. We suggest that age-related loss of collagen in connective tissues undergoing turnover may be a manifestation of a deregulated increase of collagen phagocytosis in which the net loss of degraded collagen exceeds new synthesis.

Periodontal management of gingival overgrowth in the heart transplant patient: a case report

Heart transplant patients take several medications that could affect their periodontal health. Gingival overgrowth associated with cyclosporin (immunosuppressant agent) and nifedipine (calcium channel blocker) is well documented. Candidal infections often develop because of immune suppression. This report describes the clinical and histopathological changes in the gingival tissues of a heart transplant patient and their management. The gingival tissues exhibited pronounced enlargement. The gingivae were lobulated, and the surface of the lobulations was pebbly and granular. Biopsies showed lobules of fibrous connective tissue covered by stratified squamous epithelium. The outer surfaces were dotted with numerous smaller papillations. Candidal hyphae were present in the superficial layers of the epithelium. The extensive papillary lesions appear to be related to candidiasis and constitute a condition which is best designated as papillary stomatitis. Hyperplastic gingival tissues were excised, and the patient was placed on periodic maintenance. One-year postoperative follow-up showed minor gingival growth.

Regression of nifedipine-induced gingival hyperplasia following switch to a same class calcium channel blocker, isradipine

Patients with nifedipine-induced gingival hyperplasia (GH) often require continued calcium channel blocker therapy. Switches to diltiazem and verapamil have been described; however, these drugs are of a different chemical class and present therapeutic limitations in some patients. The purpose of this study was to evaluate the effect on nifedipine-induced GH of a switch to a dihydropyridine derivative with a low incidence of GH. Fourteen patients with nifedipine-induced GH were given a medical exam and a periodontal exam. The following parameters were assessed: probing depth (PD), gingival margin (GM), gingival thickness (GT), plaque index (PI), and gingival index (GI). Intraoral photographs, study models, and a gingival biopsy for histological examination were taken. Following baseline measures, patients were randomized to continued treatment with nifedipine or an equivalent dose of isradipine in a single-blind fashion. Biweekly periodontal parameters were taken for 8 weeks. At the end of 8 weeks, some patients elected to receive 4 weeks of open label isradipine therapy, with biweekly examination continuing through the open label phase. The isradipine treatment arm showed a mean decrease in PD of 0.59 mm at week 8 (P < 0.05). No other measured parameter (GM, GT, PI, GI) was significantly changed, compared either to baseline or to the alternate treatment arm. Clinically, 60% of patients treated with isradipine exhibited a decrease in hyperplasia, while 66% of patients treated with nifedipine demonstrated an increase in hyperplasia, a significant difference (P < 0.05). When combined with open label data, patients switching therapy to isradipine exhibited an increase in GM (increase in recession) of 0.74 mm from baseline to week 12 (P < 0.05). No patients treated with isradipine exhibited an increase in gingival overgrowth. All patients exhibited adequate control of hypertension. We conclude that in hypertensive patients with nifedipine-induced GH, switching hypertensive therapy to isradipine may result in a regression of GH. When coupled with aggressive oral hygiene treatment, this drug may provide a reasonable option for patients requiring dihydropyridine treatment.

Lack of influence of cyclosporin A on levels of gingival procollagen types I and III mRNAs in rats of different ages

Previous studies showed that gingival overgrowth following cyclosporin A (CsA) administration is not associated with an increase in interstitial collagen. It also was shown that CsA causes a significant decrease in collagen content within the gingival stroma. In order to determine whether this decrease is caused by down-regulation of collagen mRNA, the procollagen mRNA level in gingiva of young and old rats was measured correlated with the ratio of interstitial collagen to DNA in these regions. Hybridization of 32P-labelled cDNA probes for procollagen types I and III with total RNA extracted from the molar gingiva showed that administration of Csa did not change the steady-state levels of mRNAs for both procollagens in the gingiva of either young or old rats. The ratio of gingival interstitial collagen to DNA was significantly reduced in the CsA-treated animals (4.2 +/- 0.85) relative to the controls (7.8 +/- 1.6). It is concluded that the reduction in interstitial collagen following CsA treatment is not age-related, and is most probably caused by increased degradation rather by decreased biosynthesis.

Vigabatrin-induced gingival overgrowth

Vigabatrin is a relatively new medication used in the treatment of epilepsia. The present report concerns the use of vigabatrin by a 19-year-old woman. The patient manifested marked gingival overgrowth compatible clinically and histologically with the overgrowth induced by phenytoin, cyclosporine and calcium channel blockers. This is the 1st report of vigabatrin-induced gingival overgrowth. Clinicians should be aware of similar lesions in patients using new anticonvulsants.

Role of integrins in regulation of collagen phagocytosis by human fibroblasts

Phagocytosis of collagen fibrils by fibroblasts is an important pathway for degradation of extracellular matrix in mature connective tissues. To study regulatory mechanisms in phagocytosis, 2-microns fluorescent beads coated with either collagen (COL) or bovine serum albumin (BSA) were incubated with human gingival fibroblasts in vitro. For these studies single cell suspensions were prepared by trypsinization, and bead internalization and collagen receptor expression were assessed by flow cytometry. After 3-h incubations, up to 8-fold more cells internalized COL beads than BSA-coated beads. Increased collagen coating concentration was associated with elevated proportions of cells that internalized COL beads, and was observed also in the presence of competing fibronectin-coated beads. The number of beads per cell and the percent of phagocytic cells increased proportionally with higher bead loadings. At > 4 beads per cell a maximum of approximately 80% of cells were phagocytic. Cells reacted with mAbs against the alpha 1, alpha 2, and alpha 3 integrin subunits were, respectively, 5%, 98% and 93% positively stained above background controls. All cells that internalized COL beads exhibited alpha 2 staining but there were large proportions of phagocytic cells that were not stained for alpha 1. In unfixed cells, bead internalization caused an immediate reduction of surface staining of membrane-bound alpha 2 by approximately 55% which returned to control levels within 3 h, indicating that cell-surface alpha 2 was internalized by phagocytosis. Preincubation of cells with up to 8 COL beads per cell reduced the proportion of phagocytic cells and the number of internalized beads after a second COL bead incubation 4 h later. To assess the relationship between the percent of phagocytic cells and alpha 2 integrin levels, serum starvation and cycloheximide experiments were conducted. Compared to controls, serum starvation for 24 h induced a 3.2-fold increase of cells internalizing COL beads but did not alter alpha 2 staining levels. In contrast, 3 h cycloheximide treatment reduced alpha 2 staining to 60% of control levels and this treatment also inhibited COL bead internalization. GRGDTP peptide as well as mAbs against the alpha 1 and alpha 2 subunits significantly reduced internalization of COL beads by 1.8 to 2.6-fold, whereas GRGESP peptide and alpha 3 mAb exerted no effect. Internalization of BSA beads was not affected by any of these treatments. Collectively, these data indicate that the alpha 2 integrin, along with other, as yet unidentified components, is likely involved in COL bead internalization. The alpha 2 integrin subunit is rapidly recycled or synthesized following a phagocytic load. In contrast, the alpha 1 integrin is not directly required for phagocytosis but may regulate the internalization step.

Histopathologic alterations of periodontium in cyclosporin-treated rats. Is the periodontium a target tissue for the drug?

Gingival dimensions and histopathologic alterations in periodontium were examined in rats continuously exposed to cyclosporin-A (CSA). 60 male Sprague-Dawley rats were divided into 2 groups. Rats in the test group daily received CSA in mineral oil by gastric feeding at a dosage of 30 mg/kg body weight for 6 weeks. Rats in the control group received mineral oil only. 10 rats from each group were sacrificed at 2-week intervals. Gingival dimensions were assessed from stone models obtained from the maxillary and mandibular incisal regions. Horizontal, sagittal and frontal tissue sections were obtained from these regions as well. Gingival dimensions in the mandibular and maxillary incisal regions were significantly increased in rats exposed to CSA. Light-microscopic observations revealed a granulation tissue formation at tooth-gingiva interface and an irregular bony surface on dental alveoli in experimental animals. Because both soft and hard tissue of periodontium in experimental rats being significantly effected by CSA compared to control animals, we hypothesized that the periodontium is a target tissue for CSA.

Phagocytosis and intracellular digestion of collagen, its role in turnover and remodelling

Collagens of most connective tissues are subject to continuous remodelling and turnover, a phenomenon which occurs under both physiological and pathological conditions. Degradation of these proteins involves participation of a variety of proteolytic enzymes including members of the following proteinase classes: matrix metalloproteinases (e.g. collagenase, gelatinase and stromelysin), cysteine proteinases (e.g. cathepsin B and L) and serine proteinases (e.g. plasmin and plasminogen activator). Convincing evidence is available indicating a pivotal role for matrix metalloproteinases, in particular collagenase, in the degradation of collagen under conditions of rapid remodelling, e.g. inflammation and involution of the uterus. Under steady state conditions, such as during turnover of soft connective tissues, involvement of collagenase has yet to be demonstrated. Under these circumstances collagen degradation is likely to take place particularly within the lysosomal apparatus after phagocytosis of the fibrils. We propose that this process involves the following steps: (i) recognition of the fibril by membrane-bound receptors (integrins?), (ii) segregation of the fibril, (iii) partial digestion of the fibril and/or its surrounding non-collagenous proteins by matrix metalloproteinases (possibly gelatinase), and finally (iv) lysosomal digestion by cysteine proteinases, such as cathepsin B and/or L. Modulation of this pathway is carried out under the influence of growth factors and cytokines, including transforming growth factor beta and interleukin 1 alpha.

Oral presentation of posttransplantation lymphoproliferative disorders. An unusual manifestation

Cyclosporine, an immunosuppressive agent widely used in organ transplantation, has several undesirable side effects, including gingival hyperplasia, which occurs in up to 70% of patients. Another complication associated with use of cyclosporine and other immunosuppressants is an increased incidence of malignancies. Long-term use of cyclosporine also is associated with a spectrum of hyperproliferative disorders ranging from reactive lymphoid hyperplasia to aggressive malignant lymphomas. While cyclosporine-related lymphoproliferative disorders have been widely reported, they have not been described in the oral cavity as the first manifestation of this disease. We report on two cardiac transplantation patients with a history of cyclosporine use who presented initially with oral symptoms of lymphoproliferative disorder. Both had erythematous to cyanotic and hyperplastic gingiva. On gingivectomy, the fixed tissue was soft, glistening, and tan colored, in contrast to the usual firm, white, cyclosporine-associated, benign gingival fibrous hyperplasia. Histologically, a dense, diffuse infiltrate of lymphoplasmacytoid cells with vesicular nuclei, prominent nucleoli, a moderate amount of cytoplasm, and high mitotic activity was observed. Immunocytochemical studies confirmed that the cells were monoclonal for lambda light chains in one patient and kappa light chains in the other. The cells from one patient were positive for CD45, while both patients were negative for CD20 and all nonhematopoietic antigens tested. Both tissues were strongly positive for Epstein-Barr virus. Morphology and immunocytochemistry findings are consistent with a posttransplant lymphoproliferative disorder. These are the first two reported cases of cyclosporine-associated posttransplant lymphoproliferative disorders presenting as gingival hyperplasia.

Changes in extracellular matrix macromolecules in human gingiva after treatment with drugs inducing gingival overgrowth

It is generally agreed that gingival overgrowth results from an increase in the levels of gingival extracellular macromolecules infiltrated with various numbers of inflammatory cells. The relative amounts of extracellular matrix macromolecules observed in 12 cases of gingival hyperplasia associated with the use of cyclosporin, hydantoin or nifedipine were compared with those obtained in a control group on the basis of histological and immunohistochemical investigations. From tissue sections, the quantification was by computerized morphometric analysis on a BFM 186 microcomputer to which were implemented the transformations of mathematical morphology. The area fractions (AA%) occupied by total collagen, type III and type IV collagen, vessels, fibroblasts, fibronectin and elastic fibres were estimated and compared. The overall histological aspects of drug-induced gingival overgrowth were similar, but quantification of different extracellular matrix components showed differences. In the nifedipine and cyclosporin groups, the area occupied by fibroblasts were not significantly greater than in healthy gingiva and chronic gingivitis. The area occupied by collagen was significantly greater in the nifedipine group than in the other pathological groups. Fibronectin was also strongly expressed in the nifedipine group, and the elastic fibre network was preserved in this group.

Intraoral pyogenic granuloma after allogeneic bone marrow transplant. Report of three cases

Allogeneic bone marrow transplant patients commonly have oral complications related to their disease or its treatment. Those reported include: xerostomia, mucositis, caries, infection, gingival hyperplasia, periodontitis, and graft-versus-host disease. These complications may be responsible for significant morbidity. This article reviews commonly reported oral complications of bone marrow transplantation and presents three cases in which intraoral pyogenic granuloma occurred. The cause of these lesions in post-bone marrow transplant patients is discussed.

Clinical and histological evaluation of ligature-induced periodontal breakdown in domestic ferrets immunosuppressed by Cyclosporin-A

The aim of this study was to evaluate, clinically and histologically, the effect of Cyclosporin-A (CyA) on the progression of the periodontal breakdown in the domestic ferret, using the ligature induced periodontitis model. At the start of the experiment (day 0), silk ligatures were placed at the gingival margin level of experimental teeth. The contralateral teeth served as non-ligated control teeth. Clinical measurements included gingival index, probing pocket depth (PPD), probing attachment level (PAL) and gingival overgrowth (GO) and they were performed on days 0, 14 and 28. Cyclosporin-A, 10 mg/kg/d, was given subcutaneously from day 0 to 21, while in the last week there was a reduction of this dose to 5 mg/kg/d. Blood samples were taken on days 0, 14 and 28. On day 28 the animals were sacrificed. Histological sections were prepared for light microscopy. The histometric measurements performed were: (1) the distance between cemento-enamel junction and the alveolar bone crest and (2) loss of connective tissue attachment. The number of sections with root resorption areas was observed. Cell counts were taken in 4 different areas. The results showed, on days 14 and 28, a significant increase of the mean values of PPD and PAL at experimental teeth as compared to the control teeth. GO was present on experimental teeth on days 14 and 28. On day 28, the control teeth presented a very small increase in GO, mainly at the buccal sites of P4 and M1. The histometric results showed a significant loss of attachment and bone resorption in the experimental teeth. Root resorption was found in experimental teeth only. The predominant inflammatory cell in the 4 experimental areas was polymorphonuclears.(ABSTRACT TRUNCATED AT 250 WORDS)

Nifedipine aggravates cyclosporine A-induced gingival hyperplasia

Gingival hyperplasia is a common side-effect of immunosuppression with cyclosporine A. Nifedipine is often used to control hypertension in kidney graft recipients. Analysis of gingival status in 106 children transplanted at our centre, and treated either with azathioprine, cyclosporine A or both, revealed significantly higher degrees of gingival overgrowth in those children receiving a combination of cyclosporine A and nifedipine compared with those children treated with cyclosporine A or nifedipine alone. Seven children undergoing gingivectomy at our centre over the past few years had received this combination. After a change in the antihypertensive regimen, avoiding long-term nifedipine medication, and improved dental care with chlorhexidine gel, we noted a reduction in the degree of gingival hyperplasia. In the majority of patients, nifedipine could be replaced by a single drug, usually hydralazine. We therefore recommend avoiding calcium channel blockers in the long-term management of hypertension in patients receiving cyclosporine.

Oral cytomegalovirus infection in an unrelated bone marrow transplantation with possible mediation by graft-versus-host disease and the use of cyclosporin-A

Graft-versus-host disease remains as a significant sequela in allogeneic bone marrow transplantation patients. Reports of oral presentations of cytomegalovirus infection in this patient population are rare. Although the usual manifestation of oral cytomegalovirus is mucosal ulceration, we report a case that we believe reflects a dynamic among graft-versus-host disease, cytomegalovirus, and the use of cyclosporin A, commonly used as an immunosuppressive agent in bone marrow transplantation.

Ultrastructural features of cyclosporine A-induced gingival hyperplasia

The present work collected data on the ultrastructural features of the attached gingiva in kidney transplant patients who showed gingival hyperplasia following cyclosporin A (Cy A) treatment. Ultrastructural examination was carried out on biopsies of attached gingiva obtained from 8 male patients (30 to 60 years old) undergoing treatment at the Dental Clinic of the University of Ferrara. The data showed that, although many fibroblasts are present in Cy A-induced hyperplasia, there is a particular abundance of amorphous substance compared to fibrous, as well as marked plasma cell infiltration. On the basis of the data collected, we hypothesize that the morphological features of the dimensional increase in gingival tissue associated with Cy A treatment in kidney transplant patients may be considered local manifestations of a systemic phenomenon.

Drug-induced gingival overgrowth

Certain anticonvulsants, cyclosporine, and a variety of calcium channel blockers have been shown to produce clinically and histologically similar gingival enlargements in certain susceptible patients. These drugs appear to be similar with respect to their pharmacologic mechanism of action at the cellular level. The primary target tissue is the most essential difference among them. Therefore it is tempting to speculate that these agents may act similarly on a common secondary target tissue, such as gingival connective tissue, and cause a hyperplastic response. This tissue reaction may involve a disturbance of calcium ion influx into specific cell populations with a resulting alteration in collagen metabolism and other host cell response mechanisms. A connection between ion exchange, folate uptake, collagenase activation, and bacterial inflammation may exist. Until a more effective approach can be developed from future research results, treatment should continue to emphasize plaque control, professional debridement, and resective gingival procedures to improve function, esthetics, and access for home care.

Deficiencies in collagen phagocytosis by human fibroblasts in vitro: a mechanism for fibrosis?

Degradation of collagen by fibroblast phagocytosis is an important pathway for physiological remodelling of soft connective tissues. Perturbations of this pathway may provide a mechanism for the development of fibrotic lesions. As collagen phagocytosis may be regulated by either a change of the proportions or the activity of phagocytic cells, we quantified phagocytosis with an in vitro model system. Collagen-coated fluorescent latex beads were incubated with human gingival fibroblasts and the fluorescence associated with internalized beads was measured by flow cytometry. Cells from normal tissues that had been incubated with beads for 3 hours contained a mean of 64% phagocytic cells; however, a small subpopulation (10% of phagocytic cells) contained more than threefold higher numbers of beads per cell than the mean. In contrast, cells from fibrotic lesions exhibited a large reduction of the proportions of phagocytic cells (mean = 13.8%) and there were no cells with high numbers of beads. On the basis of 3H-Tdr labeling, cells from fibrotic lesions that had internalized beads failed to proliferate, in contrast to phagocytic cells from normal tissues, which underwent repeated cell divisions. This result was not due to variations of cell cycle phase as there was no preferential internalization of beads during different phases of the cell cycle. The low phagocytic rate of cells from fibrotic lesions was also not due to asymmetric partitioning of phagosomes at mitosis as videocinemicrography of bead-labeled phagosomes in single, pre-mitotic cells demonstrated that > 90% of phagocytic cells equally partitioned beads to daughter cells. To investigate if inhibition of phagocytosis could be replicated in vitro, cells were incubated with the fibrosis-inducing drugs nifedipine or dilantin. These cultures exhibited marked (15-75%), dose-dependent reductions in the proportions of phagocytic cells, but there was no reduction in bead number per cell. Fibrotic lesions appear to contain fibroblasts with marked deficiencies in phagocytosis and the reduced phagocytic activity of these cells may contribute to unbalanced degradation and fibrosis.

The effect of cyclosporin and lipopolysaccharide on fibroblasts: implications for cyclosporin-induced gingival overgrowth

Drug-induced gingival overgrowth is an adverse side effect associated principally with 3 different types of drugs; specifically the antiepileptic phenytoin, the calcium channel antagonist nifedipine, and the immunosuppressant cyclosporin. The present study has analyzed the effect of cyclosporin and lipopolysaccharide on fibroblasts from 3 different sources: 1) normal healthy human gingiva (NHGF); 2) overgrown gingiva from 2 patients taking cyclosporin (CHGF); and 3) human fetal lung (WI-38). Fibroblasts isolated from cyclosporin-associated gingival overgrowth were significantly less responsive to cyclosporin in terms of DNA, total protein, and proteoglycan synthesis. This finding supports the in vivo response where few fibroblasts are seen but marked overgrowth of fibrous tissue occurs. Lipopolysaccharide derived from Fusobacterium nucleatum and Escherichia coli was capable of inhibiting DNA synthesis significantly in all 3 fibroblast types. Total protein synthesis by CHGF cells was inhibited differentially by Fusobacterium nucleatum LPS and addition of cyclosporin to this system resulted in reversal of the inhibition. A synergistic effect was noted when the proteoglycan output of NHGF cells was assessed in response to co-incubation with cyclosporin and Escherichia coli LPS. The study shows that bacterial LPS may be an important co-factor in the pathogenesis of cyclosporin-induced gingival overgrowth.