Stimulation of collagen and glycosaminoglycan production by phenytoin 5,5-diphenylhydantoin in monolayer cultures of mesenchymal cells derived from embryonic chick sternae

Do vascular endothelial growth factor and basic fibroblast growth factor promote phenytoin's wound healing effect in rat? An immunohistochemical and histopathologic study

BACKGROUND

This study was designed to determine the possible correlation between phenytoin and vascular endothelial growth factor and basic fibroblast growth factor in the wound healing process.

METHODS

Sixty Wistar albino rats were divided into four groups, each containing 15 animals. The experimental groups received a daily phenytoin treatment (10 mg) for 3 or 7 days following 3-cm dorsal skin incisions on the midline; the control group incisions were treated with 0.5 mL of saline solution during the same time periods. After completion of treatments, all animals were killed, and skin tissue samples were obtained.

RESULTS

Histopathologic examination of all groups revealed that there were significantly increased (p<0.05) amounts of fibroblasts, collagen deposition, and blood vessels in the phenytoin-treated groups when compared to the control groups. Although immunolocalization of vascular endothelial growth factor and basic fibroblast growth factor was weak in the 3-day phenytoin treatment groups, they were strongly expressed in the 7-day treatment group when compared to the control groups.

CONCLUSION

The findings of this study demonstrate that the tissue alterations of the wound healing process could be accelerated by phenytoin and the potential local pathways of vascular endothelial growth factor and basic fibroblast growth factor.

Differential proliferation of fibroblasts cultured from hereditary gingival fibromatosis and normal gingiva

Hereditary gingival fibromatosis (HGF) is an oral condition characterized by the enlargement of the gingiva of both the maxilla and mandible. To study the cell proliferation index of fibroblasts from HGF and normal gingiva (NG), cell cultures from 4 members of the same family with HGF and from 4 healthy patients were established. Our results obtained from 6 different cell proliferation assays clearly showed that the cell proliferation rate was significantly higher in fibroblasts from HGF than from normal gingiva. HGF and control fibroblasts in subconfluent culture densities were typically spindle, but in saturation density HGF cells were shorter than control cells. These data suggest that the higher proliferative index of HGF fibroblasts possibly has a role in the pathogenesis of gingival outgrowth in HGF patients.

Diphenylhydantoin affects glycosaminoglycans and collagen production by human fibroblasts from cleft palate patients

During embryonic development, the proper production of extracellular matrix molecules mediates morphogenetic processes involved in palatogenesis. In the present study, we investigated whether any differences exist in glycosaminoglycan (GAG) and collagen synthesis between palate fibroblasts from infants, with or without cleft palate, in two age ranges. Subsequently, the effects of diphenylhydantoin (PHT), a teratogen known to induce cleft palate in human and mammalian newborns, on extracellular matrix (ECM) production were studied. We found that cleft palate fibroblasts (CPFs) synthesize greater amounts of GAG and collagen than normal fibroblasts (NFs). CPFs produced less cellular hyaluronic acid (HA) and more sulphated GAG. HA was the principal GAG species in the medium, and its percentage was lower in one- to three-year-old CPFs. Cleft palate fibroblasts produced more extracellular chondroitin 4- and 6-sulphate (CS) and dermatan sulphate (DS). Associated with a higher production of sulphated GAG, we observed a higher synthesis of type III and type I collagen with a normal ratio of alpha2(I) to alpha1(I) chains. PHT treatment of NFs reduced collagen and GAG synthesis, with a marked effect on sulphated GAG. The drug changed collagen synthesis, whereas it did not affect GAG production in CPFs whose phenotype may already be impaired. These findings indicate that, in CPFs, modifications in the pattern of ECM components, which are most likely responsible for the anomalous development, persist in infants. In addition, NFs and CPFs with a different phenotype respond differently to PHT treatment.

Interleukin-1 beta and phenytoin reduce alpha 1 (I) procollagen mRNA expression in human gingival fibroblasts

Effects of and interactions between interleukin-1 beta (IL-1 beta) and phenytoin (PHT) on alpha 1 (I) procollagen gene and protein expression in human gingival fibroblasts and its relation to prostaglandin E2 (PGE2) formation were studied. IL-1 beta (300 pg/ ml) reduced the steady-state level of alpha 1 (I) procollagen mRNA by 50% and decreased the amount of procollagen I by 35%. PHT (10 micrograms/ml) reduced the level of alpha 1 (I) procollagen mRNA by 40% but the amount of procollagen I in the medium was unchanged. In combination with IL-1 beta, PHT potentiated the inhibitory effect of IL-1 beta on alpha 1 (I) procollagen mRNA level that was accompanied by an increased PGE2 formation. Preincubation with indomethacin (10(-6) M) partially reduced the inhibitory effect of IL-1 beta as well as of IL-1 beta in combination with PHT on the mRNA level of alpha 1 (I) procollagen. The inhibitory effect of PHT was unaffected by indomethacin treatment. Addition of exogenous PGE2 (> or = 10 nM) dose-dependently reduced steady-state level of alpha 1 (I) procollagen mRNA as well as the amount of procollagen 1. The study indicates that IL-1 reduces the expression of alpha 1 (I) procollagen mRNA in human gingival fibroblasts partly by a prostaglandin endoperoxide (PGH) synthase-mediated pathway and partly by a PGH-synthase independent pathway, whereas PHT reduces alpha 1 (I) procollagen gene expression by a PGH-synthase independent pathway. The potentiation of the inhibitory effect of IL-1 induced by PHT was mediated mainly by a PGH-synthase dependent pathway.

Topical phenytoin in the treatment of split-thickness skin autograft donor sites: a comparative study with polyurethane membrane drape and conventional dressing

The effectiveness of topical phenytoin as a wound healing agent was compared with that of OpSite (Smith & Nephew) and a conventional topical antibiotic dressing (Soframycin, Roussel) in a controlled study of 60 patients with partial-thickness skin autograft donor sites on the lower extremities. Mean time to complete healing (complete epithelialization) was 6.2 +/- 1.6 days in the phenytoin-treated group (30 patients), compared to 8.6 +/- 2.2 days with OpSite (15 patients), and 12.6 +/- 3.4 days in the 15 Soframycin-treated patients. The differences between the treatment groups were significant at P < 0.001. Mean pain scores were also lower in the phenytoin-treated group, 0.40 +/- 0.55 vs. 0.66 +/- 0.60 with OpSite (P < 0.05) and 1.4 +/- 0.50 with the conventional dressing (P < 0.001). Both phenytoin and OpSite were superior to the Soframycin dressing with respect to bacterial contamination and wound infection as measured by Gram stains of wound smears, swab and aspirate (OpSite) cultures, and clinical assessments (P < 0.001) carried out on the fifth day of treatment. No local or systemic adverse effects of the three agents used were noted. Phenytoin appears to be an effective, low-cost and safe method for the treatment of partial-thickness skin graft donor sites, comparing very favourably with, and in some aspects superior to, occlusive dressings. Further clinical use and evaluation of topical phenytoin are merited.

Topical phenytoin in wound healing

BACKGROUND

Phenytoin, introduced in 1937 as an antiseizure medication, has since been reported to promote wound healing when applied as a topical agent. This study was undertaken to evaluate its effectiveness in chronic skin ulcers.

METHODS

Seventy-five inpatients with chronic skin ulcers were included in this controlled trial. Forty patients were treated with topical phenytoin, and 35 patients with conventional saline dressings. Assessment of the wounds included wound area, bacteriologic cultures, and clinical assessment by blind observers at baseline and every 7 days thereafter over the 4-week treatment period.

RESULTS

Wound area reduction was greater in the phenytoin group than in controls. Fifty percent of phenytoin-treated wounds had negative cultures by day 7, compared to 17% of controls. Healthy granulation tissue appeared earlier with phenytoin. At the end of the fourth week, 29 of 40 phenytoin-treated ulcers had healed completely versus 10 of 35 controls.

CONCLUSIONS

Topical phenytoin appears to be an effective, inexpensive, and widely available therapeutic agent in wound healing. Further clinical use and evaluation is merited.

Comparison of topical phenytoin with normal saline in the treatment of chronic trophic ulcers in leprosy

BACKGROUND

Trophic ulceration, one of the most common complications of leprosy, is disabling, distressing, and demoralizing for the patient.

METHODS

The wound healing effects of topical phenytoin powder were compared with those of normal saline in a controlled in-patient study of 100 patients with 110 trophic leprosy ulcers of varying chronicity, over a 4-week study period. Fifty patients were assigned to the topical phenytoin group and 50 to saline therapy group. Ten patients had two ulcers each, and, in these cases, one ulcer was treated with phenytoin and the other with saline.

RESULTS

Over the 4-week treatment period healthy granulation tissue appeared earlier, and mean percentage of ulcer volume reduction was greater, in the phenytoin group (72.1 +/- 19.9% versus 55.5 +/- 21.6%) compared with the control group.

CONCLUSIONS

This difference was statistically significant at the level of P < 0.001. Phenytoin appears to be a useful agent for the promotion of healing of trophic leprosy ulcers.

Role of phenytoin in healing of large abscess cavities

The promotion of healing of large abscess cavities attained with topical phenytoin was evaluated in controlled studies of clinical and experimental wounds. In the clinical abscess cavities, phenytoin application in 20 patients compared with conventional treatment in 20 patients resulted in earlier separation of slough, decrease in oedema, control of pain and overall enhanced healing. The mean(s.d.) rate of reduction of wound area was 2.02(0.48) cm2/day in the phenytoin group versus 1.58(0.51) cm2/day in controls (P less than 0.05) on day 10, and 1.8(0.32) cm2/day versus 1.19(0.21) cm2/day (P less than 0.01) on day 20. The mean volume reduction rates at both the 10th and 20th day were 0.48(0.01) cm3/day for phenytoin versus 0.32(0.04) cm3/day for controls; (P less than 0.005). By day 20, 17 of the patients treated with phenytoin were rated as having healed completely, compared with only one of the controls. In a standardized guinea-pig model of the clinical abscess cavity, which included inoculation of the wound with Bacillus proteus and Klebsiella pneumoniae, an enhanced healing rate was also observed (at 7 days 0.40(0.05) cm2/day with phenytoin versus 0.21(0.08) cm2/day in controls; P less than 0.005). All eight of the animals treated with phenytoin healed by day 21, compared with one of the eight controls. Biopsies of wounds treated with phenytoin showed less inflammation, no necrosis, and enhanced neovascularization, collagen deposition and fibroblast proliferation compared to controls. Bacterial colonies also decreased more rapidly with the use of phenytoin.

Effect of phenytoin and nifedipine on collagen gene expression in human gingival fibroblasts

Phenytoin (PHT), a widely used anticonvulsant, and nifedipine (NF), an anti-anginal drug, cause clinically similar gingival overgrowths in some patients. The aim of this work was to investigate their effects on collagen and protein synthesis and cellular proliferation in normal human gingival fibroblasts in vitro. Gingival fibroblasts were cultured from biopsies taken from three healthy individuals during operations on maxillary canines and incubated with various concentrations of NF (100 and 200 ng/ml) and PHT (5 and 10 micrograms/ml) for up to 7 days. The results showed that NF and PHT have a specific effect in reducing total protein and collagen synthesis but do not influence cell proliferation in healthy gingival fibroblasts in vitro. In addition the level of mRNA for type I collagen was decreased after incubation of the cells with the drugs for 1 or 2 days. The decrease in the level of type I collagen mRNA seemed to be specific since the level of type IV collagenase mRNA used as a reference RNA did not decrease.

Effect of phenytoin medication on the metabolism of epidermal growth factor receptor in cultured gingival fibroblasts

Human gingival fibroblasts derived from 2 patients before and 9 months after the start of phenytoin (PHT) therapy were studied with respect to the effect of epidermal growth factor (EGF) on the incorporation of 3H-thymidine into DNA, binding of EGF to its cell-surface receptor, internalization of EGF-receptor-ligand complexes and, finally, with respect to EGF receptor mRNA levels. In fibroblasts derived from the patient who developed gingival overgrowth during the PHT medication (responder) as well as in the fibroblasts derived from the patient where gingival overgrowth did not develop (non-responder), the affinity of the EGF receptor for EGF was not significantly changed. In the non-responder patient the internalization of EGF receptor ligand was decreased, whereas it was increased in the fibroblasts derived from the responder patient after PHT therapy. The steady-state level of EGF-r mRNA increased significantly (p less than 0.001) in the cultured fibroblasts derived from the non-responder but decreased (p less than 0.05) in the responder patient following PHT therapy. Ligand affinity cross-linking studies revealed one major component of EGF receptor with a molecular weight of 170 KDa in fibroblasts from the non-responder as well as from the responder. The study indicates that PHT medication results in a down-regulation of EGF receptor metabolism in fibroblasts derived from a responder patient, whereas in the non-responder patient EGF receptor metabolism is up-regulated.

Stimulation of collagen synthesis in fibroblast cultures by a triterpene extracted from Centella asiatica

The drug "Titrated Extract from Centella asiatica" (TECA), used for its stimulating properties on the healing of wounds, is a mixture of 3 terpenes extracted from a tropical plant: asiatic acid (30%, w/w), madecassic acid (30%, w/w) and asiaticoside (40%, w/w). The effects of TECA and its individual components were checked on human foreskin fibroblast monolayer cultures. TECA increased the collagen synthesis in a dose-dependent fashion whereas a simultaneous decrease in the specific activity of neosynthesized collagen was observed. Asiatic acid was found to be the only component responsible for collagen synthesis stimulation. TECA and all three terpenes increased the intracellular free proline pool. This effect was independent of the stimulation of collagen synthesis.

Phenytoin-induced gingival overgrowth in rats infected with Streptococcus sobrinus 6715

Inbred Fischer rats were fed a high sucrose diet (No. 2000) containing phenytoin (5,5-diphenyl-hydantoin) for 52 days, which produced serum and salivary PHT levels of 13-14 and 2.6-2.7 micrograms/ml, respectively. Gingival overgrowth was induced in the molar region of all PHT-treated rats but was more severe in Streptococcus sobrinus 6715-infected rats than in non-infected rats, which had lower plaque scores. No significant overgrowth was found in rats infected with Strep. sobrinus and fed the same diet without PHT. Thus dental plaque accumulation enhanced, but was not essential for the development of the PHT-induced gingival overgrowth. Histological examination showed that the density of fibroblasts and connective tissue fibres was similar in all groups. This experimental model could serve as a useful means of understanding the pathogenesis of PHT-induced gingival overgrowth.