Factors influencing nifedipine-induced gingival overgrowth in rats

Gingival Enlargement Caused by Calcium Channel Blockers

Calcium channel blockers, a group of drugs widely used in the treatment of cardiovascular patients, although effective, often cause gingival enlargement, a side effect that is rarely recognized in clinical practice and is not given sufficient importance. Gingival enlargement caused by calcium channel blockers can be localized or generalized, mild or severe. It can negatively affect patients’ appearance, mastication, and speech, thus considerably reducing the quality of life of patients. Risk factors and pathogenesis of this side effect have been the subject of many studies but are still unknown, making this condition a major therapeutic challenge, especially if the cessation of the offending drug is not possible. This study aimed to review the etiology, potential risk factors, pathogenesis, clinical features, and therapy possibilities for gingival enlargement caused by calcium channel blockers.

Role of IL-6 and STAT3 signaling in dihydropyridine-induced gingival overgrowth fibroblasts

OBJECTIVES

This study analyzed the role of the interleukin (IL)-6/signal transducer and activator of transcription 3 (STAT3) pathway in dihydropyridine-induced gingival overgrowth (DIGO) fibroblasts.

MATERIALS AND METHODS

Tissue samples were obtained through surgical dissection from five DIGO patients and five healthy individuals. Cell cultures were conditioned with nifedipine (Nif) (0.34 µM) and stimulated with IL-1β (10 ng/ml) to clarify whether IL-6 upregulates extracellular matrix overproduction or has an impact on the cell proliferation rate of DIGO fibroblasts. STAT3 was knocked down using short hairpin (sh)RNA to determine its role in collagen (Col) type I alpha 1 (Colα1(I)) synthesis.

RESULTS

Results showed that phosphorylated (p)STAT3 nuclear translocation was activated by a simulated autocrine concentration (50 ng/ml) of IL-6, and application of an anti-IL-6 antibody significantly decreased the pSTAT3/STAT3 ratio in DIGO fibroblasts. STAT3 knockdown significantly decreased STAT3 and Colα1(I) expressions in DIGO cells. DIGO tissues presented stronger proliferating cell nuclear antigen (PCNA) expression than did healthy individuals under the effect of IL-1β/Nif treatment.

CONCLUSIONS

Gingival inflammation (e.g., IL-1β) and taking dihydropyridine (e.g., Nif) may additively stimulate Col overproduction through the IL-6-STAT3-Colα1(I) cascade in DIGO cells. IL-6-STAT3 signaling may be considered a target for the control of DIGO.

Calcium channel blocker induced gingival enlargement following implant placement in a fibula free flap reconstruction of the mandible: a case report

Background

Gingival tissue enlargement is a common side effect of antiepileptic medications (e.g. phenytoin and sodium valproate), immunosuppressing drugs (e.g. cyclosporine) and calcium channel blockers (e.g. nifedipine, verapamil, amlodipine) (Murakami et al. 2018, Clin Periodontol 45:S17–S27, 2018). The clinical and histological appearances of lesions caused by these drugs are indistinguishable from one another (Murakami et al. 2018, Clin Periodontol 45:S17–S27, 2018). Drug-induced gingival enlargement is rarely seen in edentulous patients.

Case presentation

This case presents a 72-year-old female with a history of squamous cell carcinoma of the floor of the mouth treated with surgical excision and fibula-free flap reconstruction. Following the uncovering of osseointegrated implants placed in the fibular-free flap, the patient developed gingival enlargement of the floor of the mouth. Cessation of amlodipine and switching to an alternative medication lead to a resolution of the enlarged tissue.

Conclusions

This case illustrates that gingival enlargement can occur around dental implants, most notably in rehabilitation cases in patients who have had head and neck cancer. Clinicians should be aware of the risk of gingival enlargement in hypertensive patients taking calcium channel blockers prior to implant placement.

Prevention of phenytoin-induced gingival overgrowth by lovastatin in mice

Drug-induced gingival overgrowth is caused by the antiseizure medication phenytoin, calcium channel blockers, and ciclosporin. Characteristics of these drug-induced gingival overgrowth lesions differ. We evaluate the ability of a mouse model to mimic human phenytoin-induced gingival overgrowth and assess the ability of a drug to prevent its development. Lovastatin was chosen based on previous analyses of tissue-specific regulation of CCN2 production in human gingival fibroblasts and the known roles of CCN2 in promoting fibrosis and epithelial to mesenchymal transition. Data indicate that anterior gingival tissue overgrowth occurred in phenytoin-treated mice based on gross tissue observations and histomorphometry of tissue sections. Molecular markers of epithelial plasticity and fibrosis were regulated by phenytoin in gingival epithelial tissues and in connective tissues similar to that seen in humans. Lovastatin attenuated epithelial gingival tissue growth in phenytoin-treated mice and altered the expressions of markers for epithelial to mesenchymal transition. Data indicate that phenytoin-induced gingival overgrowth in mice mimics molecular aspects of human gingival overgrowth and that lovastatin normalizes the tissue morphology and the expression of the molecular markers studied. Data are consistent with characterization of phenytoin-induced human gingival overgrowth in vivo and in vitro characteristics of cultured human gingival epithelial and connective tissue cells. Findings suggest that statins may serve to prevent or attenuate phenytoin-induced human gingival overgrowth, although specific human studies are required.

Calcium channel blocker-induced gingival enlargement

Despite the popularity and wide acceptance of the calcium channel blockers (CCBs) by the medical community, their oral impact is rarely recognized or discussed. CCBs, as a group, have been frequently implicated as an etiologic factor for a common oral condition seen among patients seeking dental care: drug-induced gingival enlargement or overgrowth. This enlargement can be localized or generalized, and can range from mild to extremely severe, affecting patient's appearance and function. Treatment options for these patients include cessation of the offending drug and substitution with another class of antihypertensive medication to prevent recurrence of the lesions. In addition, depending on the severity of the gingival overgrowth, nonsurgical and surgical periodontal therapy may be required. The overall objective of this article is to review the etiology and known risk factors of these lesions, their clinical manifestations and periodontal management.

Amlodipine-Induced Gingival Hyperplasia in a Child: Case Report and a Review of the Literature

Objective:

To increase awareness of amlodipine-induced gingival hyperplasia in children, as well as review whether a dose-related relationship exists.

Case Summary:

A 9-year-old girl with a past medical history of membranous nephropathy and hypertension presented with failure to thrive and inability to gain weight. She had a history of allergy to enalapril. On admission, she was found to have gingival hyperplasia. A review of her medication profile found amlodipine and azathioprine to be possible agents for this adverse reaction. The child's mother noticed this adverse effect after an increase in amlodipine dosage. We recommended substituting the angiotensin receptor blocker losartan for amlodipine; however, the nephrologist feared a cross-reactivity with enalapril and decided to continue amlodipine therapy. A follow-up call after hospital discharge revealed that the patient could no longer eat by mouth and that her gums bled upon brushing.

Discussion:

We reviewed the possible role of azathioprine in causing our patient's gingival hyperplasia. Due to the timeliness of this occurrence and the possibility of a dose-related response, we selectively reviewed the literature associated with amlodipine in children. A PubMed search and subsequent review of the literature revealed 1 study in rats that showed a relationship between amlodipine dose/plasma concentration and gingival hyperplasia. In humans, this relationship was reported with other calcium channel blockers, but not with amlodipine and not in a child. The Naranjo probability scale revealed a possible adverse reaction of gingival hyperplasia associated with amlodipine.

Conclusions:

To our knowledge, this is the first report of a possible dose-related occurrence of gingival hyperplasia in a child receiving amlodipine.

Flutamide inhibits nifedipine- and interleukin-1 beta-induced collagen overproduction in gingival fibroblasts

BACKGROUND AND OBJECTIVE

To understand the role of the androgen receptor in gingival overgrowth, the effects of flutamide on interleukin-1 beta- and nifedipine-induced gene expression of connective tissue growth factor (CTGF/CCN2) and collagen production in gingival fibroblasts were examined.

MATERIAL AND METHODS

Gingival fibroblasts from healthy subjects and patients with dihydropyridine-induced gingival overgrowth (DIGO) were used. Confluent cells were treated with nifedipine, interleukin-1 beta or both. The mRNA expression was examined using real-time polymerase chain reaction, and the concentration of total soluble collagen in conditioned media was analysed by Sircol Collagen Assay. In addition, the protein expressions of androgen receptor, CTGF/CCN2 and type I collagen in gingival tissue were determined by western blot.

RESULTS

Interleukin-1 beta was more potent than nifedipine in stimulating CTGF/CCN2 and procollagen alpha1(I) mRNA expression, and there was an additive effect of the two drugs. Healthy cells exhibited an equal or stronger response of procollagen alpha1(I) than those with DIGO, but DIGO cells displayed a stronger response in the secretion of soluble collagen in the same conditions. Flutamide, an androgen receptor antagonist, inhibited stimulation by nifedipine or interleukin-1 beta. Additionally, the protein expressions of androgen receptor and type I collagen were higher in DIGO gingival tissue than those in healthy gingival tissue.

CONCLUSION

The data suggest that both nifedipine and interleukin-1 beta play an important role in DIGO via androgen receptor upregulation and that gingival overgrowth is mainly due to collagen accumulation. Flutamide decreases the gene expression and protein production of collagen from dihydropyridine-induced overgrowth cells.

Non-surgical treatment of gingival overgrowth induced by nifedipine: a case report on an elderly patient

Drug-induced gingival overgrowth (DIGO) is a significant problem for periodontologists and this side effect is frequently associated with three particular drugs: phenytoin, cyclosporin A and nifedipine. A case report of gingival overgrowth induced by nifedipine in an elderly patient treated with non-surgical periodontal therapy is described. A 75-year-old male with generalised gingival overgrowth reported the problem of oral malodour and significant gingival bleeding. The medical history revealed a controlled hypertensive state and Cerebral Vascular Accident (CVA) 3 years prior to consultation. The diagnosis was gingival overgrowth associated with nifedipine, no other risk factors being identified. The patient had been taking nifedipine for 18 months, but after the consultation with the patient's doctor, nifedipine was suspended, as the hypertension was controlled. Treatment consisted of meticulous oral hygiene instruction, scaling, root surface instrumentation and prophylaxis. Six months after the first intervention, clinical parameters revealed a significant improvement with a considerable reduction in gingival overgrowth, demonstrating the effect of non-surgical periodontal therapy in severe cases of gingival overgrowth. Non-surgical treatment of DIGO is a far less invasive technique than surgical approaches and has demonstrated an impressively positive treatment response. It should therefore be considered as a first treatment option for DIGO.

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.

Diltiazem did not induce gingival overgrowth in rats: a clinical, histological and histometric analysis

The administration of calcium channel blockers has been associated with gingival overgrowth. However, there are few studies in humans or animals that evaluated the effect of diltiazem on gingival tissues. The present study assessed the influence of diltiazem, at different dosages and treatment duration, on gingival tissues of rats, using clinical, histological and histometric analyses. Eighty young male rats were separated into eight groups according to the dosage and duration of treatment. Rats were treated for 20 or 40 days with a daily subcutaneous injection of 5, 20 or 50 mg/kg of body weight of diltiazem. The results confirmed that diltiazem did not induce gingival overgrowth in rats. For all animals, the evaluation did not show gingival alterations regardless of the dosages and periods of treatment. The histometric analysis showed no significant change in the area of epithelium and connective tissues, although after 40 days of treatment a decrease in the area of connective tissue was observed, without statistically significant difference from control groups. Within the limits of this study, we suggest that diltiazem did not induce gingival overgrowth.

On the relation of nitric oxide to nifedipine-induced gingival hyperplasia and impaired submandibular glands function in rats in vivo

Calcium-channel blockers such as nifedipine could be associated with gingival overgrowth. The aim of this study was to examine the role of nitric oxide (NO) on nifedipine-induced gingival hyperplasia along with submandibular secretory function in rats. Animals in divided groups received nifedipine (250 mg/kg diet) alone and in combination with L-arginine (2.25% w/v) or N(omega)-nitro-L-arginine methyl ester (L-NAME) (0.7% w/v) in drinking water for 20 days. Controls received only tap water. Pure submandibular saliva was collected intraorally by micropolyethylene cannula and the mandibular gingiva was examined by means of dissecting microscope for signs of redness, thickness, inflammation and exuda. Twenty-day nifedipine treatment induced gingival hyperplasia accompanied with reduced salivary flow rate and concentrations of total protein, epidermal growth factor (EGF) and calcium in comparison with controls. Co-treatment of animals with nifedipine and L-arginine protected from gingival hyperplasia and retained flow rate, and concentrations of total protein, EGF and calcium in normal levels. Co-treatment of animals with nifedipine and L-NAME potentiated nifedipine-induced gingival hyperplasia and reductions in flow rate and concentrations of total protein, EGF, and calcium. It is concluded that nifedipine-induced gingival hyperplasia is associated with salivary dysfunction. Activation of cGMP-dependent positive signal-transduction mechanisms in salivary glands might be the mechanism for protective effects of NO against nifedipine-induced gingival hyperplasia.

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.

Synergistic enhancement of collagenous protein synthesis by human gingival fibroblasts exposed to nifedipine and TNF-alpha in vitro

BACKGROUND

Gingival overgrowth occurs in patients receiving nifedipine. Gingival inflammation may be an etiologic factor.

METHODS

Gingival fibroblasts were either exposed to (i) 0-500 ng/ml TNF-alpha or 10(-7) M nifedipine or (ii) 0-500 ng/ml TNF-alpha + 10(-7) M nifedipine for 7 days. 3H-proline was used to quantify collagenous protein synthesis.

RESULTS

Both TNF-alpha and 10(-7) M nifedipine significantly decreased cell proliferation, and 10(-7) M nifedipine + 500 ng/ml TNF-alpha reversed these effects. Collagenous protein synthesis was significantly reduced by TNF-alpha and was significantly enhanced by either 10(-7) M nifedipine or 5-500 ng/ml TNF-alpha + 10(-7) M nifedipine.

CONCLUSIONS

Our data report that nifedipine reverses the primary effects of TNF-alpha on collagenous protein synthesis. Patients with gingivitis could be susceptible to gingival overgrowth during nifedipine therapy as a result of synergistic effects of these agents on fibroblast metabolism, which occurs irrespective of reduced cell numbers.

Nifedipine induces gingival epithelial hyperplasia in rats through inhibition of apoptosis

BACKGROUND

Nifedipine is used as a long-acting vasodilator; one of its side effects is gingival overgrowth, characterized by an accumulation of collagenous components within the gingival connective tissue and epithelial hyperplasia with elongated, branched rete pegs penetrating into the connective tissue. We investigated the effect of nifedipine on apoptosis of gingival keratinocytes of rats to elucidate the mechanism of nifedipine-induced gingival epithelial hyperplasia.

METHODS

Twenty-day-old rats were fed a powdered diet containing or lacking nifedipine for 8 to 30 days. The mandibular gingiva and palatal mucosa were removed on days 8, 15, or 30, and epithelial thickness was examined by light microscopy. In situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay was used to examine apoptosis of keratinocytes in the epithelium. In addition, we examined the effects of nifedipine on proliferation of keratinocytes and epithelial cell life on day 8 by 5-bromo-2'-deoxyuridine (BrdU) staining.

RESULTS

Microscopic examination showed gingival epithelial hyperplasia in nifedipine-treated rats after day 15. Apoptosis of gingival keratinocytes was seen to be inhibited in nifedipine-treated rats on day 8 and 15. Also, nifedipine did not induce an increase of keratinocyte proliferation activity in terms of the number of cells showing positive staining with BrdU. Prolongation of cell life by nifedipine was observed on day 8 in gingival epithelium through a delay of upward cell movement compared to controls. However, epithelial hyperplasia was not detected in palatal mucosa, and there were no significant differences in apoptotic rates of keratinocytes and cell life between nifedipine-treated rats and control rats.

CONCLUSIONS

These results suggest that nifedipine induces epithelial hyperplasia in gingival overgrowth not by an increase in keratinocyte proliferation, but by prolongation of cell life through reduction of apoptosis before epithelial hyperplasia is detectable.

Effect of nifedipine on the expression of p53 protein in rat gingiva

The aim of the present study was to determine the profile of p53 protein expression in gingival tissues after treatment with nifedipine in rats. Rats were treated daily by gastric intubation with or without DMSO alone or DMSO-dissolved nifedipine at concentrations of 15, 30 or 60 mg/kg body weight for 1, 3 or 6 week(s). Gingival width and height were measured macroscopically. Monoclonal antibodies recognizing both wild-type and mutant p53 protein were applied on paraffin-embedded gingival sections using microwave pretreatment and immunohistochemical methods. The gingival width and height were increased in the animals treated with nifedipine at concentrations of 30 and 60 mg/kg body weight. Increased gingival width and height were already seen in the animals treated with 60 mg of nifedipine for 1 week, whereas treatments with 30 mg of nifedipine resulted in increased gingival width and height after treatment for at least 3 weeks. The expression of p53 protein was elevated in the animals treated with 30 or 60 mg of nifedipine. Treatments with nifedipine at the concentration of 60 mg/kg body weight for 1 week induced the expression of p53 protein in the gingival tissues. Treatment with nifedipine in rats led to the inducement of gingival hyperplasia and increase in the numbers of p53-positive gingival epithelial cells by a dose and frequency dependent mechanism, suggesting that p53 protein may play a crucial role in the regulation of nifedipine-induced gingival hyperplasia.

Nifedipine induces gingival overgrowth in rats through a reduction in collagen phagocytosis by gingival fibroblasts

BACKGROUND

Nifedipine is used as a long-acting vasodilator, and a primary side effect is the induction of gingival overgrowth, which is characterized by an accumulation of collagenous components within the gingival connective tissue. To elucidate the mechanisms of nifedipine-induced gingival overgrowth, we investigated the effect of nifedipine on Type I collagen metabolism in the gingiva of rats.

METHODS

Twenty-day-old rats were fed a powdered diet containing or lacking nifedipine for 3 to 55 days. Immunohistochemical analysis with anti-Type I collagen antibody was employed to examine the density of Type I collagen in the gingival connective tissue. Total RNAs were isolated from mandibular molar gingiva on days 0, 3, 15, 30, and 55, and reverse transcription polymerase chain reaction was performed to investigate the mRNA levels of Type I collagen. In addition, we performed a flow cytometric analysis with collagen-coated latex beads and cultured fibroblasts derived from rat gingiva to measure collagen phagocytosis.

RESULTS

Immunohistochemical analysis revealed that Type I collagen was more prevalent in the connective tissue of nifedipine-treated gingiva than in controls on day 55. In the nifedipine-treated group, the expression of Type I collagen mRNA gradually decreased to 1.5% on day 55 compared to day 0. In the control group, Type I collagen mRNA also decreased to 32%; however, mRNA expression was significantly lower in the nifedipine-treated group than in the controls. When the rate of phagocytic cells derived from nifedipine-treated gingiva and controls was represented as the mean +/- SE of the percentage from 3 different experiments, the values were as follows: on day 15, 13.5 +/- 2.1% and 15.0 +/- 1.5%; on day 30, 12.2 +/- 4.3% and 34.5 +/- 6.7% in the nifedipine-treated and the control group, respectively, indicating that phagocytic cells were considerably fewer in the nifedipine-treated gingiva on day 30. This finding demonstrates that the decrease in phagocytosis caused by nifedipine appeared before the detection of severe macroscopic gingival overgrowth.

CONCLUSION

These findings suggest that the decrease in collagen degradation due to lower phagocytosis is closely associated with the increase in Type I collagen accumulation in nifedipine-treated rat gingiva.

Effects of combined oral treatments with cyclosporine A and nifedipine or diltiazem on drug-induced gingival overgrowth in rats

BACKGROUND

Cyclosporine A (CsA) and calcium channel blockers induce gingival overgrowth in humans and animals. Recently, nifedipine and diltiazem have often been used to control CsA-related hypertension in organ transplant patients. The purpose of this study was to examine the effects of a combined oral treatment of CsA and nifedipine or diltiazem on the severity of gingival overgrowth in rats.

METHODS

Fifteen-day-old Fischer rats were treated orally with single or combined applications of CsA, nifedipine, and/or diltiazem for 40 days; and induced gingival overgrowth, rat growth, and blood drug levels were compared among the different experimental groups. The experiment consisted of 6 groups: one control group (group A) and 5 test groups treated with CsA (group B), nifedipine (group C), and diltiazem (group D), as well as those concurrently treated with CsA and nifedipine (group E), and CsA and diltiazem (group F). Gingival overgrowth was determined by measuring the depth of the gingival sulcus.

RESULTS

The mandibular buccal gingival sulcus depth of group A was 365 +/- 41.2 microm. Among the test groups, the most remarkable gingival overgrowth was seen in group E (1,020 +/- 63.3 microm), followed by group F (895 +/- 43.8 microm), group B (870 +/- 48.3 microm), group C (525 +/- 116 microm), and then group D (505 +/- 83.2 microm). Rat body weight gain was reduced significantly by oral CsA treatment. Neither nifedipine nor diltiazem suppressed rat growth when used independently; however, rat growth reduced by CsA was further suppressed by a combined use of diltiazem, but not nifedipine. CsA blood levels were reduced by concurrent oral treatment with nifedipine or diltiazem along with the blood levels of those calcium channel blockers when treatment was in combination with CsA.

CONCLUSIONS

These results suggest that gingival overgrowth is induced in rats as a side effect of CsA, nifedipine, or diltiazem, and the combined use of these drugs influences rat growth, blood drug levels, and the severity of gingival overgrowth.

Prevalence of gingival overgrowth induced by calcium channel blockers: a community-based study

BACKGROUND

The prevalence of gingival overgrowth induced by chronic medication with calcium channel blockers is uncertain. Although there have been several studies examining this question, the results are conflicting, with previous estimates ranging from 20% to 83%. There have been only 2 studies examining the prevalence of overgrowth induced by diltiazem and amlodipine, with estimates of 74% and 3.3%, respectively.

METHODS

The current study aimed to address the problems associated with these studies by examining a sample of patients taking one of 3 calcium channel blockers, who were drawn from a community-based population in northeastern England. Nine hundred eleven (911) subjects were recruited from general medical practices in the area. Of these, 442 were taking nifedipine, 181 amlodipine, and 186 diltiazem. In addition, 102 control subjects were examined. Drug and demographic data for each subject were recorded. The periodontal condition of all subjects was assessed including plaque index, papillary bleeding index, and a photograph of the anterior gingivae for subsequent analysis of overgrowth severity.

RESULTS

More than six percent (6.3%) of subjects taking nifedipine were seen to have significant overgrowth. This overgrowth was statistically greater than the amount of overgrowth seen in either of the other 2 drug groups or the control population. The prevalence of gingival overgrowth induced by amlodipine or diltiazem was not statistically significant when compared to the control group. The severity of overgrowth within the nifedipine group was found to be related to the amount of gingival inflammation and also to the gender of the subject, with males being 3 times as likely to develop overgrowth than females.

CONCLUSIONS

The prevalence of clinically significant overgrowth related to chronic medication with calcium channel blockers is low, i.e., 6.3% for nifedipine. Males are 3 times as likely as females to develop clinically significant overgrowth. The presence of gingival inflammation is an important cofactor for the expression of this effect.

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.

Role of medullasin in nifedipine-induced gingival overgrowth in rats

To clarify the possible pathophysiological role of medullasin, a neutrophil elastase-like proteinase, in nifedipine (NF)-induced gingival overgrowth, a rat model of gingival overgrowth was first established using a diet containing NF. The relation between histopathological changes and the distribution of the proteinase was then investigated. Thirty-two, specific pathogen-free 20 day-old, male, Fisher 344 rats were fed a diet containing NF and killed at 2, 8, 16 and 32 weeks. Control rats (n = 32) were fed the same diet but without the drug. The mandible of each rat was resected and sectioned at 4-microm thickness buccolingually between the first and second molars. Computer image analysis was used to evaluate the extent of overgrowth in the approximal gingiva of each sample. To examine medullasin activity, the mean percentage of medullasin-positive cells per total cells counted in the pocket epithelium and the connective tissue adjacent to the epithelium of approximal gingiva was determined immunohistochemically. The height of the mid-portion and the area in NF-treated group increased significantly with time (with the exception of area at 2 weeks) compared with the corresponding regions in the control group. A marked inflammatory-cell infiltration and elongated rete pegs, especially in the mid-portion of approximal gingiva, were seen in the NF-treated group. The mean percentages of medullasin-positive cells in the NF-treated group at 8, 16 and 32 weeks were significantly higher than those of the control. Although medullasin-positive cells were mainly neutrophils, in several samples of the NF-treated group they were recognized as macrophage-like. These findings suggest that medullasin may be involved in host defence and immunoregulation in a NF-induced rat model of gingival overgrowth.

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.

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.

Subgingival microflora associated with nifedipine-induced gingival overgrowth

The purpose of this study was to examine the composition of subgingival plaque of 140 periodontal lesions in 35 patients with cardiovascular disorders who were administered nifedipine and manifested nifedipine-induced gingival overgrowth (GO). Age was inversely associated with the GO. Plaque index and bleeding index showed a significant association with GO, while nifedipine dosage and duration of nifedipine therapy were not found to be significant predictors of GO. The gingival inflammation as expressed in the logistic regression model by the interaction term color x tone was found to be significantly associated with the GO. Statistically significant differences between the groups of comparable probing depth and different degrees of GO were detected for Propionibacterium acnes, Capnocytophaga gingivalis, Capnocytophaga ochracea, Capnocytophaga sputigena, Bacteroides gracilis, Fusobacterium mortiferum, Fusobacterium nucleatum, Fusobacterium varium and Selenomonas sputigena in deep and enlarged lesions. Significantly more frequently isolated were the bacterial species Eubacterium alactolyticum, Campylobacter concisus, C. gingivalis, C. ochracea, C. sputigena, F. mortiferum, F. nucleatum, and F. varium from the more enlarged lesions (GO >3).

The clinical effects of nifedipine on periodontal status

The present study was conducted to determine the clinical effects of nifedipine on the gingiva of 97 patients. Patients were examined for changes in periodontal status and divided into subgroups, based on their age, gender, duration of drug intake, presence/absence of plaque and gingival inflammation, and according to the presence and severity of gingival overgrowth. Gingival overgrowth was noticed in 29% of the patients. Among the recorded parameters, duration of drug intake, presence/severity of gingival inflammation, and gender seemed to have the greatest effect on the development of gingival overgrowth. Patients with higher gingival inflammation scores, those on nifedipine medication for more than 4 years, and males were likely to have an increased tendency for higher incidence and severity of gingival overgrowth. The findings of the present study suggest that nifedipine medication induces gingival overgrowth and that certain local factors are involved in the pathogenesis of drug-induced gingival overgrowth. However, individual ability and sensitivity to metabolize the drug and its metabolites also seem to be important etiological factors.

Use of calcium channel blockers and breast carcinoma risk in postmenopausal women

BACKGROUND

The use of calcium channel blockers in an elderly population recently was reported to be associated with the incidence of cancer. The Cardiovascular Health Study, a multisite observational cohort study, provided the opportunity to investigate the epidemiologic association between the use of calcium channel blockers and breast carcinoma risk in 3198 women age > or = 65 years.

METHODS

Standard questionnaires and clinical procedures were administered at four study sites annually from 1989-1990 to 1993-1994. Drug usage was assessed by a medication inventory and hospitalizations for 75 incident invasive breast carcinoma cases were identified using International Classification of Diseases-9 Clinical Modification codes. Time-dependent Cox proportional hazards regression models were used to assess associations between incident breast carcinoma and the use of specific antihypertensive medication including calcium channel blockers.

RESULTS

In adjusted Cox proportional hazards models, an elevated risk of breast carcinoma was associated with use of calcium channel blockers (hazard ratio [HR]: 2.57; 95% confidence interval [CI], 1.47-4.49). This association persisted when the comparison group was users of other antihypertensive medication. No associations between the use of other antihypertensive medication with incident breast carcinoma were found. Associations were enhanced by assessment of high dose at baseline (HR: 4.42; 95% CI, 1.37-14.27) and when calcium channel blockers were combined with estrogen use (HR: 4.48; 95% CI, 1.58-12.75). The association was found to be strongest for the use of estrogens with immediate release calcium channel blockers (HR: 8.48; 95% CI, 2.99-24.08).

CONCLUSIONS

Although the number of cases was limited in this observational study, associations found between the use of calcium channel blockers and incident invasive breast carcinoma warrant further investigation. Site specific carcinomas should be included as an outcome of ongoing and planned long term clinical trials using calcium channel blockers.

Positive correlation between blood cyclosporin A level and severity of gingival overgrowth in rats

Cyclosporin a is a drug used to control rejection of organ transplantation and autoimmune diseases; however, it has also been implicated in gingival overgrowth. The present study investigates the relationship between severity of gingival overgrowth and blood cyclosporin A (CsA) levels in Fischer rats treated orally with CsA. Thirty-six 15-day-old male rats were divided into six experimental groups and given powdered rat chow containing 0, 50, 100, 200, 300, and 400 micrograms CsA/g diet ad libitum for 40 days. At the end of the 40-day treatment period, whole blood samples were collected from each rat for assessment of CsA levels. The rats were then sacrificed and the gingival sulcus depth (pseudopocket) around mandibular molars measured to estimate gingival overgrowth. The blood levels of CsA in rats increased with increasing amounts of CsA provided in their food. A 100% incidence in gingival overgrowth was induced in all the rats treated orally with CsA. The overgrowth was more severe in buccal than in lingual gingiva. A significantly positive correlation was found between gingival sulcus depth and the blood CsA level (rs = 0.914, P < 0.0001; Spearman's correlation coefficient by rank). On histological examination, the overgrown gingiva consisted of a thickened epithelial layer and an accumulation of subepithelial fibrous connective tissue components without marked distortion of their proportion.

Periodontal implications: medically compromised patients

The presence of systemic disease in patients requiring periodontal therapy creates challenges for management. Alteration of treatment plans, with emphasis on physician consultation and preventive periodontal care, is frequently needed to minimize the impact of periodontal disease on the systemic condition. Conversely, detection and treatment of systemic disorders may impact upon the status of the periodontium and the success of periodontal therapy. The goal of holistic patient management is facilitated by a free flow of information between the patients and their medical and dental health care providers.

Pathogenesis of drug-induced gingival overgrowth. A review of studies in the rat model

Drug-induced gingival overgrowth is a side effect associated principally with 3 types of drugs: anticonvulsant (phenytoin), immunosuppressant (cyclosporine A), and various calcium channel blockers (nifedipine, verapamil, diltiazem). In this review, we describe the features of phenytoin-, cyclosporine A- and nifedipine-induced gingival overgrowth in rats and discuss factors influencing the onset and severity of these disorders. There are several features common to the gingival overgrowth induced by these drugs: 1) gingival overgrowth is more conspicuous in the buccal than in the lingual gingiva and less severe in the maxilla than in the mandible; 2) once the blood concentration of the drug reaches a certain level as a result of increasing the dose, the incidence of gingival overgrowth is 100% and its severity is dependent on the blood level, the most severe overgrowth being induced by cyclosporine A; 3) the duration of drug administration for maximal gingival overgrowth to develop is about 40 days; 4) the gingival overgrowth regresses spontaneously after discontinuing the drug; 5) accumulation of dental plaque is not essential for the onset of overgrowth, but plays a role in its severity; and 6) more severe overgrowth is induced in young than in old rats. Furthermore, male rats are more susceptible than females to nifedipine-induced gingival overgrowth. These results suggest that drug-induced gingival overgrowth in rats is dependent on the oral drug dose, blood drug level, age, and sex and that preexisting gingival inflammation is a factor relevant to its severity. Since these factors have also been suggested to be important determinants for human drug-induced gingival overgrowth, the rat model may prove valuable in the future for elucidating the molecular pathogenesis of the disorder.