Differential Effects of Hormones on Cellular Metabolism in Keratoconus In Vitro

Abstract

Keratoconus (KC) is a corneal thinning disease with an onset commonly immediately post-puberty and stabilization by 40 to 50 years of age. The role of hormones in regulating corneal tissue structure in homeostatic and pathological conditions is unknown. Our group recently linked altered hormone levels to KC. Our current study sought to investigate and delineate the effects of exogenous hormones, such as androgen, luteotropin, and estrogen, on corneal stroma bioenergetics. We utilized our established 3D in vitro model to characterize the effects of DHEA, prolactin, 17β-estradiol on insulin-growth factor-1 and -2 (IGF-1, -2) signaling and metabolic function in primary corneal fibroblasts from healthy controls (HCFs) and KC patients (HKCs). Our data showed that exogenous DHEA significantly downregulated IGF-1 and its receptor in both HCFs and HKCs with HKCs showing consistently lower basal pentose phosphate flux. Prolactin caused no significant change in IGF-1 levels and an increase in IGF-2 in HKCs correlating with an increase in ATP and NADH levels. 17β-estradiol led to a significant upregulation in pentose phosphate flux and glycolytic intermediates in HCFs. Our results identified hormone-specific responses regulated in HKCs compared to HCFs revealing a novel role for hormones on bioenergetics in KC.

Assembly and Application of a Three‐Dimensional Human Corneal Tissue Model

“…Cultures beyond 8 weeks may be possible but are limited by the passage number of the primary hCECs and hCSSCs. This timeframe is consistent with self‐assembled stromal models that rely on de novo ECM deposition by human corneal fibroblasts and can be maintained for 4 to 11 weeks (Guo et al., ; Ren et al., ), followed by analysis of the biochemical responses to various chemical or environmental stimuli (McKay, Hjortdal, Priyadarsini, & Karamichos, ; McKay, Hjortdal, Sejersen, & Karamichos, ).…”

Gonadotropins in Keratoconus: The Unexpected Suspects

“…To our knowledge the two hormones, and/or their ratio, have never been investigated, or reported, in the context of KC. Based on our findings, we postulate that FSH and/or LH dysfunction is the cause for the abnormal modulation of DHEA-S, estriol, and estrone, we see further downstream [10].…”

“…Hunting for an etiology for the appearance and progression of KC, studies have been reporting a slew of contributing factors including genetics [7], environmental conditions [1,8], eye rubbing [9], and hormonal imbalances [10]. Recently, our group has been focusing on hormonal imbalances and their role on KC.…”

Tear Mediators NGF along with IL-13 Predict Keratoconus Progression

“…3 The etiology of this visually debilitating disease is not yet known in detail, but recent studies suggest that the pathogenesis is related to a combination of genetic, biomechanical, biochemical and environmental risk factors including inflammation, oxidative stress, and allergy. [4][5][6][7][8][9][10][11][12][13][14][15][16] Altered levels of various cytokines, enzymes, regulatory and growth factors, and diagnostic markers of inflammation and tissue injury have been found in the tears or in the cornea of patients with keratoconus, pointing to the crucial role of the immune system in the pathogenesis of keratoconus. 6,[11][12][13][14] These include proinflammatory cytokines (tumor necrosis factor (TNF), interleukin (IL)-1β, IL-6), inflammatory chemokines (CXCL8, CCL5), inflammatory mediators (IL-12, interferon (IFN)-γ, IL-17), the anti-inflammatory cytokine IL-10, cytokines associated with allergy development (IL-4, IL-13), enzymes and their co-factors associated with tissue remodeling (matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinase-1 (TIMP-1), cathepsin B).…”

“…[4][5][6][7][8][9][10][11][12][13][14][15][16] Altered levels of various cytokines, enzymes, regulatory and growth factors, and diagnostic markers of inflammation and tissue injury have been found in the tears or in the cornea of patients with keratoconus, pointing to the crucial role of the immune system in the pathogenesis of keratoconus. 6,[11][12][13][14] These include proinflammatory cytokines (tumor necrosis factor (TNF), interleukin (IL)-1β, IL-6), inflammatory chemokines (CXCL8, CCL5), inflammatory mediators (IL-12, interferon (IFN)-γ, IL-17), the anti-inflammatory cytokine IL-10, cytokines associated with allergy development (IL-4, IL-13), enzymes and their co-factors associated with tissue remodeling (matrix metalloproteinases (MMPs), tissue inhibitor of metalloproteinase-1 (TIMP-1), cathepsin B). Various growth factors, other enzymes, enzyme inhibitors, cellular proteins which can serve as diagnostic markers in the context of cellular and tissue injury or inflammation were also described, including epidermal growth factor (EGF), vascular endothelial growth factor (VEGF); insulin-growth factors (IGFs), nerve growth factor (NGF), lipocalins, lipophilins, phospholipase A2, cystatins, albumin, type I and type II keratins, lactoferrin, Prolactin-Induced Protein, α-fibrinogen, α1-antitrypsin; apolipoprotein A1 (ApoA1), lysozyme C, zinc-α2-glycoprotein (ZAG), metabolic enzymes (e.g.…”