(103) THE CROSSROADS OF INFLAMMATION AND SCARRING IN VULVAR LICHEN SCLEROSUS
Authors: Fischer S , Updike A , Boachie B , Greene C , Agwaze R , Ahmmed F , Linder M , Falsetta Wood M 
Published: June 2024

Abstract

Introduction
Vulvar lichen sclerosus (VLS) is a chronic inflammatory skin condition that is a leading cause of sexual dysfunction. VLS skin becomes fragile, thickened, and extremely itchy. As disease advances, scarring of the vulva, resorption of the labia and clitoris, or even cancer can occur. VLS makes sexual intercourse painful and greatly impairs quality of life. Despite impacting millions of patients, VLS remains poorly understood and is underrepresented in education and research. Current treatments are effective at managing the symptoms but do not target or reverse the underlying disease. To reduce the morbidity and mortality associated with this condition, early diagnostics and targeted therapeutics are desperately needed. Inflammation and scarring are distinguishing factors, but how these processes interact remains unknown. Fibroblasts are a class of cells responsible for producing extracellular matrix (ECM) and inflammatory cytokines, and we have established a cell-based model of disease to investigate their role in VLS further. We hypothesize that fibroblasts are key modulators in mechanism by coordinating inflammatory and fibrotic responses in VLS.

Objective
We aim to elucidate the role of fibroblasts in driving inflammation and fibrosis in VLS with the goal of identifying disease-specific biomarkers.

Methods
6 mm punch biopsies of vulvar skin were collected from eight VLS patients and six healthy individuals. For VLS cases, biopsies of visibly affected and unaffected areas were collected for within-patient comparisons. Biopsies were cut in half to analyze vulvar skin gene expression and to establish primary human fibroblasts. Cells were treated with transforming growth factor beta (TGF-β) to stimulate scarring and inflammatory pathways. Production of cytokines and ECM materials was assessed utilizing quantitative polymerase chain reaction (qPCR), western blot, and enzyme-linked immunosorbent assay (ELISA) techniques. Data analysis was conducted using ANOVA and t-tests, and the threshold for significance was p&lt;0.05.

Results
When stimulated with TGF-β, fibroblasts cultured from VLS scars produce significantly more α-smooth muscle actin (α-SMA) and downstream signaling proteins (phospho-SMAD2) compared to cells grown from unscarred areas. In addition, production of ECM components such as collagen, fibronectin, and calponin is dysregulated. However, compared to cells cultured from healthy vulvar skin, VLS fibroblasts produce significantly more pro-inflammatory cytokines, such as interleukin 6 (IL-6) and interleukin 8 (IL-8), even at baseline.

Conclusions
Inflammation and fibrosis lead to irreversible changes in VLS, but how this occurs is poorly elucidated. Fibroblasts are likely key contributors, responding to TGF-β to activate downstream signaling pathways that result in myofibroblast activation, accumulation of ECM, and excessive production of cytokines. IL-8 in particular, a neutrophil chemokine, is perpetually high in VLS fibroblasts, which may serve to recruit immune cells to fibrotic areas. Further investigation into the interplay and order of these molecular events is needed to understand the progression of this disease and to identify improved targets for therapeutics.

Disclosure
Any of the authors act as a consultant, employee or shareholder of an industry for: SPM Therapeutics.