Selective modulation of the keratoconic stromal microenvironment by FSH and LH.

Keratoconus (KC) affects corneal structure, resulting in thinning and bulging outward into a cone shape. Irregular astigmatism and decreased visual acuity appear during puberty and progress into the mid-30s, with unpredictable disease severity. The cause of KC is recognized as multifactorial, but remains poorly understood. Hormonal imbalances are a significant modulator for the onset of KC. This study sought to investigate the role of gonadotropins; follicular stimulating hormone (FSH) and luteinizing hormone (LH) in KC using a 3D self-assembled matrix in-vitro model. Healthy and keratoconic corneal stromal cells (HCFs and HKCs respectively) were isolated, cultured, and stimulated with stable Vitamin C to promote extracellular matrix assembly. The cultures were further stimulated with 2.5 or 10miu/mL FSH and 5 and 35miu/mL of LH. All samples were evaluated for cell proliferation and morphology via BrdU assay and imaging, as well as, protein expression via Western blot analysis. We observed significantly higher proliferation rates in HKCs compared to HCFs with LH stimulation with no changes in FSH stimulation. Additionally, we observed significant changes in sex hormone receptors, fibrotic markers, proteoglycans, and members of the gonadotropin signaling pathway that were largely driven by exogenous LH. We demonstrated the impact of exogenous FSH/LH in the KC stromal microenvironment. The role of FSH/LH in KC and in human corneal homeostasis, should further be examined and delineated.