Expression of sex steroid hormone receptors in human cornea

Abstract

Since receptors for both male and female sex hormones are present in human corneas of both genders, we postulate that the receptors may influence the biological functions of corneal cells through direct interaction with specific hormones.

Pregnancy-related exacerbation of iatrogenic keratectasia despite corneal collagen crosslinking

“…There is growing evidence that changes in estrogen levels may play a role in LASIK-induced keratectasia: Estrogen receptors have been identified in the cornea, 6 and exposure to estrogen reduced the biomechanical stability of the cornea in an experimental study. 7 These data suggest that changes in estrogen levels may reduce the biomechanical stability of the cornea, which leads to the onset of iatrogenic keratectasia after LASIK.…”

Detection of Oestrogen receptors (ER) α and β in conjunctiva, lacrimal gland, and tarsal plates

“…7 Regarding ocular tissues, ERb mRNA was detected only in the human cornea and retina to date. 8,9 With immunohistochemical techniques, ERa could be detected in meibomian glands both in male and female subjects. 10 Depending on age, ERa expression was also proven in the female neurosensory retina and the retinal pigment epithelium.…”

Progression of Keratoconus following Hormone Replacement Therapy

“…Estrogen stimulates synthesis of glycosaminoglycans resulting in enriching of the water content and thus increasing corneal thickness which ultimately causes weakening of collagen network. 4 This may be the cause for the small increase in the pachymetry of our patient in one eye. Thus the overall effect of estrogen on the biomechanics of cornea results a small increase in corneal thickness and distensibility but reduced stiffness.…”

“…Human corneal keratocytes contain estrogen receptors(ER-α, ER-β) where estrogen initiates the biochemical changes in the stroma and also on the endothelial cells. 3,4 Corneal stiffness is determined by extracellular matrix which mainly consists collagen, proteoglycans and glycosaminoglycans. 4 Estradiol, the active form of estrogen also stimulates the production of matrix metalloproteinases 7 and production or activation of other collagenolytic enzymes thus weakening the collagen network.8 It also increases prostaglandins secretion which is responsible for activation of collagenase.…”

“…2 Estrogen receptors have been identified in the cornea 3 and the action of estrogen causes a change in the corneal biochemical stability and hence reduces corneal stiffness. 4,5 Apart from this, estrogen also shows an effect on the pachymetric values by causing a paradoxical increase in the corneal thickness. 5 Hormone Replacement Therapy (HRT) used to treat menopausal symptoms usually has a combination of estrogen and progesterone supplements.…”