Phenytoin and Cyclosporine A Specifically Regulate Macrophage Phenotype and Expression of Platelet‐Derived Growth Factor and Interleukin‐1 In Vitro and In Vivo: Possible Molecular Mechanism of Drug‐Induced Gingival Hyperplasia

Abstract

Phenytoin (pht) is an anticonvulsant drug commonly used for the prevention of seizures. A common side effect of PHT therapy is gingival hyperplasia, occasionally so severe that it requires surgical intervention. Cyclosporine A (CSA) is a drug widely used for the control of rejection phenomena following solid organ and bone marrow transplantation. A frequent side effect of CSA administration is gingival overgrowth. As yet, the molecular mechanisms of drug-induced gingival hyperplasia are unknown although it has been postulated that certain drugs increase fibroblastic activity through alterations in levels of various growth factors and cytokines. The purpose of this study was to: 1) evaluate monocyte/macrophage platelet-derived growth factor (PDGF) and interleukin (IL)-1 beta production in vitro after exposure to CSA; 2) determine the levels of PDGF-B and IL-1 beta gene expression in minimally inflamed gingival tissues of control patients and PHT-treated patients exhibiting gingival overgrowth as well as patients with severe gingival inflammation; and 3) combine characterization of macrophage phenotype with clinical presentation and expression of PDGF-B and IL-1 beta in gingival tissues from the control and PHT-treated patients. For the in vitro studies, commercial ELISA kits were used to measure PDGF-A/PDGF-B and IL-1 beta levels in conditioned media from rat and human monocyte/macrophage cell cultures. CSA caused a significant elevation of PDGF but did not cause any changes in IL-1 beta levels. For the in vivo studies, quantitative competitive reverse transcription polymerase chain reaction (QC-RTPCR) techniques were utilized to measure PDGF-B and IL-1 beta mRNA levels in experimental groups. PHT-treated patients exhibiting gingival overgrowth demonstrated a significant increase in PDGF-B mRNA compared with minimally inflamed controls. Patients with severe gingival inflammation also demonstrated a significant increase in PDGF-B mRNA however, PHT-induced PDGF-B upregulation is approximately 6 times larger than PDGF-B upregulation produced by inflammation alone. PHT-treated patients exhibiting gingival overgrowth demonstrated no significant increase in IL-1 beta mRNA; however, IL-1 beta mRNA levels in the severely inflamed gingival samples demonstrated a significant increase. Additionally, for the clinical samples, macrophage phenotype was characterized immunohistochemically in adjacent sections using specific monoclonal antibodies for inflammatory and reparative/proliferative phenotypes. There were no significant differences in the numbers of either macrophage phenotype in minimally inflamed gingival tissues; however, in the severely inflamed tissue, there was a significant increase in the inflammatory macrophage phenotype and in the hyperplastic gingival tissue, there was a significant increase in the reparative/proliferative macrophage phenotype. The results of this investigation indicate that the clinical presentation of inflamed and hyperplastic gingival tissues is associated with specific macrophages phenotyp...

In vivo association of immunophenotyped macrophages expressing CD163 with PDGF-B in gingival overgrowth-induced by three different categories of medications

“…35 The present study showed elevated expression of CD163 in group II compared to groups III and IV. This is in accordance with Dill et al 36 and Iacopino et al 6 as they concluded that PNT, CsA, and nifedipine GO tissues contain subpopulations of macrophages and other inflammatory cells. These cells differ from those in healthy control gingival tissues.…”

“…2,3 The incidence of this side effect can be as high as 70% in transplant patients, 65% in epileptics, and 30% in hypertensive patients. 4,5 In 1997, Iacopino et al 6 reported that the clinical presentation of inflamed and hyperplastic gingival tissues are associated with specific macrophage phenotypes which express the essential platelet derived growth factor-beta (PDGF-B) in PNT-induced hyperplastic tissues. In contrary, Wright et al concluded that macrophage-derived PDGF B plays a negligible pivotal role in the pathogenesis of DIGO.…”

Epithelial to Mesenchymal Transition in Gingival Overgrowth

“…By contrast, we speculate that EMT in nifedipine-and cyclosporine A-induced gingival overgrowth may be driven by elevated levels of growth factors other than TGF-␤ (such as PDGF) that have been reported to be elevated in gingival overgrowth. 39 TGF-␤1 increases SLUG levels in EMT directly through SMAD-3 signaling.…”

Connective Tissue Metabolism and Gingival Overgrowth

“…These findings are of great interest, and suggest that substances that cause gingival overgrowth may do so by altering the normal balance of cytokines in gingival tissues. Cytokines and growth factors found at elevated levels in human drug-induced gingival overgrowth include interleukin-6 (IL-6), IL-1␤, platelet-derived growth factor-B (PDGF-B), fibroblast growth factor-2 (FGF-2), transforming growth factor-␤ (TGF-␤), and connective tissue growth factor (CTGF) (Williamson et al, 1994;Nares et al, 1996;Plemons et al, 1996;Saito et al, 1996;Dill and Iacopino, 1997;Iacopino et al, 1997;Atilla and Kutukculer, 1998;Sasaki and Maita, 1998;Hong et al, 1999;Myrillas et al, 1999;Buduneli et al, 2001;Uzel et al, 2001).…”

“…In contrast, macrophages in highly inflamed tissues express predominantly the 27E10 marker . Even though IL-1␤ levels have not been shown to be increased in cyclosporin-A-treated monocytes/macrophages, there was a significant up-regulation in PDGF-B in response to cyclosporin A and phenytoin (Plemons et al, 1996;Iacopino et al, 1997). Similarly, phenytoin, cyclosporin A, and nifedipine gingival overgrowth tissues contain subpopulations of macrophages and other inflammatory cells that differ from those in healthy control gingival tissues (Dahllof et al, 1985;Pernu et al, 1994;Cebeci et al, 1996Cebeci et al, , 1998Pernu and Knuuttila, 2001;Bulut et al, 2002;Echelard et al, 2002).…”