title: Cyclosporine A upregulates platelet-derived growth factor B chain in hyperplastic human gingiva.
abstract: 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.
authors.affiliation: Department of Biomedical Sciences, Baylor College of Dentistry, Dallas, TX, USA.
authors.forename: S
authors.initials: S
authors.lastname: Nares
authors.forename: M C
authors.initials: MC
authors.lastname: Ng
authors.forename: R E
authors.initials: RE
authors.lastname: Dill
authors.forename: B
authors.initials: B
authors.lastname: Park
authors.forename: C W
authors.initials: CW
authors.lastname: Cutler
authors.forename: A M
authors.initials: AM
authors.lastname: Iacopino
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D000077214:Becaplermin; D003238:Connective Tissue / Q000378:metabolism / Q000473:pathology; D016572:Cyclosporine / Q000009:adverse effects*; D019085:Fluorescent Antibody Technique, Direct; D005786:Gene Expression Regulation / Q000187:drug effects; D005885:Gingival Hyperplasia / Q000139:chemically induced / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects*; D039564:Integrin alphaV; D016023:Integrins / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D008875:Middle Aged; D010982:Platelet-Derived Growth Factor / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D015854:Up-Regulation / Q000187:drug effects* / Q000235:genetics
chemical_list: D015703:Antigens, CD; D007166:Immunosuppressive Agents; D039564:Integrin alphaV; D016023:Integrins; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger; C095477:platelet-derived growth factor AB; D000077214:Becaplermin; D016572:Cyclosporine