Abstract: PD50-10
Sources of Funding: International Collaboration on Repair Discoveries (ICORD)

Introduction

Scarring secondary to mesh and prosthetic materials is a serious clinical problem within the GU tract. Fibrotic matrices contain fibronectin; and alpha-smooth muscle actin contributes contraction. Metalloproteinases (MMPs) such as MMP-1 and -3 can modulate matrix protein accumulation through degradation. Results from our institution have shown that silica materials can directly induce scarring through the interaction with tissue fibroblasts in vitro. By extension, we hypothesized that other materials may induce fibrotic changes through cellular matrix gene expression. Objectives: 1) to establish a 3D model of human fibroblasts to study patterns of fibroblast response to materials and 2) measure gene expression in human fibroblasts exposed to prosthetic and mesh materials compared to a control.

Methods

Collagen gel was prepared by using 3 mg/ml in final concentration with 0.5% of polyvinyl alcohol (PVA). Mesh or catheter materials and human dermal fibroblasts (70,000 /ml) were added to a collagen gel and seeded in a 24-well plate (0.5 ml of gel in each well) to create a 3D environment for fibroblast response. After polymerization of collagen, another 250,000 cells in 0.5 ml medium were added on the top of gel. Cells were cultured at 37 0C, 5% CO2 for indicated time point. Images of cells were taken under reverse microscopy to determine the pattern of the scarring contraction. Gel cell matrix was harvested and digested with 1 mg/ml of collagenase for 15 minutes, pelleted by centrifugation and RNA was extracted. RT-PCR was performed for 32 cycles to analyze gene expression.

Results

After 5 days, fibroblast contractions were identified surrounding prosthetic materials but not within the control. There were increases in type 1 collagen, ?-smooth muscle actin and fibronectin expression in fibroblasts exposed to prosthetic materials compared to fibroblasts grown in collagen gel alone. MMP-1 and MMP-3 were also detected.

Conclusions

Fibroblasts exposed to mesh and catheter materials responded with an increase in fibronectin, alpha smooth muscle actin and type 1 collagen that is increased compared to controls. This may indicate why in vivo these materials induce fibrosis. Because fibronectin, type 1 collagen and alpha smooth muscle actin are main components of scarring and their gene expression is elevated, future directions include development of medical devices that could induce downregulation of these genes.

Funding

International Collaboration on Repair Discoveries (ICORD)