Fibroblasts from recurrent fibrotic overgrowths reveal high rate of proliferation in vitro - findings from the study of hereditary and idiopathic gingival fibromatosis

ABSTRACT

Purpose: Investigate the content of fibrotic fibrils in gingival tissue and the proliferation of fibroblasts collected from recurrent and non-recurrent hereditary gingival fibromatosis (HGF) and idiopathic gingival fibromatosis (IGF).

Methods: Gingival biopsies were collected from HGF (n = 3) and IGF (n = 3) donors with recurrent and non-recurrent gingival overgrowths and from a control group (Ctrl, n = 3). Hematoxylin staining was performed to evaluate the histomorphology of gingival tissue. Heidenhain’s AZAN trichrome staining served for visualization of fibrotic fibrils in gingiva. Quantitative analysis of the content of fibrotic fibrils in gingival tissue was performed using a polarized light microscope. Proliferation was evaluated at 24 h, 48 h, and 72 h in fibroblast cultures using a cell proliferation ELISA assay based on 5-bromo-2ʹ-deoxyuridine (BrdU).

Results: Numerous blood vessels and fibroblasts were observed in recurrent overgrowths, whereas moderate blood vessels and moderate to scanty fibroblasts were detected in non-recurrent overgrowths. Heidenhain’s staining revealed numerous collagen fibers in both recurrent and non-recurrent overgrowths. Quantitative analysis in a polarizing microscope showed significant accumulation of fibrotic fibrils exclusively in the overgrowths with the recurrence. In all time-points, increased proliferation of cells from all recurrent overgrowths was observed, but not from overgrowths which do not reoccur.

Conclusions: The study revealed that recurrent gingival overgrowths consist of highly fibrotic and dense connective tissue with numerous blood vessels and abundant fibroblasts. We also demonstrated that unlike fibroblasts derived from overgrowths, which did not present recurrence, fibroblasts derived from highly fibrotic and recurrent overgrowths maintain high rate of proliferation in vitro.

KEYWORDS:

• Collagen type I
• fibroblast proliferation
• fibrosis
• gingival fibromatosis
• recurrence

Disclosure statement

No potential conflict of interest was reported by the authors.

Authors’ contributions

KG: substantial contributions to the conception and design of the work; acquisition, analysis and interpretation of data; drafting the work for important intellectual content

KŁB: acquisition and analysis of data; drafting the work

AK: acquisition and analysis of data; drafting the work

GB: acquisition and analysis of data; drafting the work

ZN: acquisition, analysis and interpretation of data; drafting the work

PP: acquisition and analysis of data; revising critically data

JP: substantial contributions to the conception of the work; revising critically data

AF: acquisition, analysis and interpretation of data; revising critically data

MCG: substantial contributions to design of the work; revising critically data

All authors: final approval of the version to be published; agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Additional information

Funding

This work was supported by grant from the National Science Centre, Poland [2012/07/B/NZ6/03524] to K.G.