Gentle cyclic straining of human fibroblasts on electrospun scaffolds enhances their regenerative potential

The extracellular matrix of fascia-like tissues is a resilient network of collagenous fibers that withstand the forces of daily life. When overstretched, the matrix may tear, with serious consequences like pelvic organ prolapse (POP). Synthetic implants can provide mechanical support and evoke a host response that induces new matrix production, thus reinforcing the fascia. However, there is considerable risk of scar formation and tissue contraction which result in severe complications. Matrix producing fibroblasts are both mechanosensitive and contractile; their behavior depends on the implant's surface texture and mechanical straining. Here we investigate the effect of both in a newly-designed experimental setting. Electrospun scaffolds of Nylon and PLGA/PCL and a non-porous PLGA/PCL film were clamped like a drumhead and seeded with fibroblasts of POP patients. Upon confluency, scaffolds were cyclically strained for 24 or 72 h at 10% and 0.2 Hz, mimicking gentle breathing. Non-loading condition was control. Strained fibroblasts loosened their actin-fibers, thereby preventing myofibroblastic differentiation. Mechanical loading upregulated genes involved in matrix synthesis (collagen I, III, V and elastin), matrix remodeling (α-SMA, TGF-β1, MMP-2) and inflammation (COX-2, TNF-α IL8, IL1-β). Collagen genes were expressed earlier under mechanical loading and the ratio of I/III collagen increased. Matrix synthesis and remodeling were stronger on the electrospun scaffolds, while inflammation was more prominent on the non-porous film. Our findings indicate that mechanical straining enhances the regenerative potential of fibroblasts for the regeneration of fascia-type tissues and limit the risk of scar tissue formation. These effects are stronger on an electrospun texture. Statement of significance: Pelvic organ prolapsed is a dysfunctional disease in female pelvic floor that can reduce the quality of life women. Currently, trans-vaginal knitted meshes are used to anatomically correct the dysfunctional tissues. However, the meshes can create sever adverse complications in some patients (e.g. chronic pain) in longer-term. As an alternative, we developed nanofibrous matrices by electrospinning based on different materials. We designed an in-vitro culture system and subjected cell-seeded matrices to cyclic mechanical loading. Results revealed that gentle straining of POP-cells on electrospun matrices, advances their regenerative potential at morphological and gene expression levels. Our findings, provide a proof-of-concept for using electrospun matrices as an alternative implant for pelvic floor repair, given that the parameters are designed efficiently and safely.