Cyclosporine A upregulates platelet-derived growth factor B chain in hyperplastic human gingiva

• Published in: Journal of periodontology (1970) Vol. 67; no. 3; p. 271
• Main Authors: Nares, S, Ng, M C, Dill, R E, Park, B, Cutler, C W, Iacopino, A M
• Format: Journal Article
• Language: English
• Published: United States 01-03-1996
• Subjects: Adult; Antigens, CD - genetics; Antigens, CD - metabolism; Connective Tissue - metabolism; Connective Tissue - pathology; Cyclosporine - adverse effects; Fluorescent Antibody Technique, Direct; Gene Expression Regulation - drug effects; Gingival Hyperplasia - chemically induced; Gingival Hyperplasia - metabolism; Gingival Hyperplasia - pathology; Humans; Immunosuppressive Agents - adverse effects; Integrin alphaV; Integrins - genetics; Integrins - metabolism; Macrophages - drug effects; Macrophages - metabolism; Middle Aged; Platelet-Derived Growth Factor - genetics; Platelet-Derived Growth Factor - metabolism; Polymerase Chain Reaction; Proto-Oncogene Proteins c-sis; RNA, Messenger - genetics; RNA, Messenger - metabolism; Transcription, Genetic; Up-Regulation - drug effects; Up-Regulation - genetics
• ISSN: 0022-3492
• DOI: 10.1902/jop.1996.67.3.271

Cyclosporine A (CSA) is a widely used immunosuppressant for transplant patients and is also used for the treatment of a wide variety of systemic diseases with immunologic components. A prominent side effect of CSA administration is gingival overgrowth (hyperplasia). It has been postulated that CSA alters fibroblast activity through effects on various growth factors/cytokines. However, as yet, data concerning the molecular mechanisms involved in pathologic connective tissue proliferation are preliminary in nature. Our previous investigations concerning phenytoin-induced effects on platelet-derived growth factor B (PDGF-B) gene expression have demonstrated that other drugs which cause gingival overgrowth can upregulate macrophage PDGF-B gene expression in vitro and in vivo. The purpose of the present study was to evaluate PDGF-B gene expression in gingival tissues of patients receiving CSA therapy and exhibiting gingival overgrowth to determine if similar PDGF-B upregulation occurs in response to CSA and to identify PDGF-B producing cells in these tissues. Quantitative competitive reverse transcription polymerase chain reaction (QC-RTPCR) techniques were utilized to measure PDGF-B mRNA levels in CSA overgrowth patients and normal controls (N = 6/group). Results were expressed as mean +/- mRNA copy number and tested for significance using unpaired t-tests. Gingival samples were harvested (standardized for local inflammation at the sample site), total RNA was extracted, and QC-RTPCR was performed using specific PDGF-B primers and a corresponding competitive internal standard. CSA-treated patients exhibiting gingival overgrowth demonstrated approximately 48-fold increase in PDGF-B mRNA (7667.1 +/- 477.4 copies for CSA patients vs. 158.2 +/- 37.1 copies for controls; P < 0.001). Additionally, dual fluorescence immunohistochemistry for mature macrophage marker antigen (CD51) and intracellular PDGF-B was utilized to identify and localize PDGF-B producing cells were demonstrated to be macrophages distributed in a non-uniform manner throughout the papillary connective tissue. These results further support the hypothesis that the molecular mechanisms responsible for drug-induced gingival overgrowth may involve upregulation of PDGF-B macrophage gene expression. We continue to investigated specific CSA-induced alterations of macrophage PDGF-B gene expression in vitro and in vivo.