Topical Losartan Inhibition of Myofibroblast Generation in Rabbit Corneas With Acute Incisions.

Purpose: The purpose of this study was to study whether deep central corneal incisions close during topical losartan treatment and the effect of topical losartan on myofibroblast generation after incisions in rabbit corneas.

Methods: Rabbits (12) had a 0.35-mm deep radial incision from the center of the cornea into the limbus in 1 eye that was approximated with a single 10-0 nylon suture 1 mm inside the limbus.

Corneal stromal localization of TGF beta isoforms in spontaneous persistent epithelial defects after PRK in rabbits.

The purpose of this study was to evaluate transforming growth factor beta (TGFβ) isoform localization in rabbit corneas with spontaneous persistent epithelial defects (PEDs) after photorefractive keratectomy (PRK). Four cryofixed corneas from a previously reported series of PEDs in rabbits that had PRK were evaluated with triplex immunohistochemistry (IHC) for TGFβ3, myofibroblast marker alpha-smooth muscle actin (α-SMA) and mesenchymal marker vimentin. One cornea had sufficient remaining tissue for triplex IHC for TGFβ1, TGFβ2, or TGFβ3 (each with α-SMA and vimentin) using isoform-specific antibodies.

Topical Losartan Decreases Myofibroblast Generation But Not Corneal Opacity After Surface Blast-Simulating Irregular PTK in Rabbits.

Purpose: To evaluate the efficacy of topical losartan after blast injury-simulating irregular phototherapeutic keratectomy (PTK) in rabbits.

Methods: Twelve NZW rabbits underwent 100 pulse 6.5 mm diameter PTK over a metal screen to generate severe surface irregularity and inhibit epithelial basement membrane regeneration.

Transforming growth factor beta-3 localization in the corneal response to epithelial-stromal injury and effects on corneal fibroblast transition to myofibroblasts.

The purpose of this study was to evaluate the localization of TGF beta-3 in situ in unwounded rabbit corneas and corneas that had epithelial-stromal injuries produced by photorefractive keratectomy (PRK) in rabbits and to evaluate the in vitro effects of TGF beta-3 compared to TGF beta-1 on alpha-smooth muscle actin (α-SMA) protein expression and myofibroblast development in corneal fibroblasts. Forty-eight New Zealand white rabbits underwent either -3 diopter (D) or -9D PRK and were studied from one to eight weeks (four corneas in each group at each time point) after surgery with immunohistochemistry for TGF beta-3, laminin alpha-5, and alpha-smooth muscle actin (α-SMA). Rabbit corneal fibroblasts were treated with activated TGF beta-1 and/or TGF beta-3 at different concentrations and duration of exposure and studied with immunocytochemistry for myofibroblast development and the expression of α-SMA using Jess automated Western blotting.

Corneal epithelial basement membrane assembly is mediated by epithelial cells in coordination with corneal fibroblasts during wound healing.

Purpose: To understand which cell types, either alone or in combination, contribute to the assembly of the epithelial basement membrane (BM) during corneal wound healing.

Methods: A 3D corneal organotypic model and an in situ rabbit photorefractive keratectomy (PRK) model were used in this study. The 3D corneal organotypic model was established by culturing the rabbit corneal epithelial cells with either corneal fibroblasts or myofibroblasts embedded in collagen type I for 18 days.

Cell Biology of Spontaneous Persistent Epithelial Defects After Photorefractive Keratectomy in Rabbits.

Purpose: To evaluate wound healing in rabbit corneas that developed a spontaneous persistent epithelial defect (PED) after photorefractive keratectomy (PRK).

Methods: Forty-eight 10- to 15-week-old female New Zealand White rabbits weighing 2.5 to 3.

Standardization of corneal alkali burn methodology in rabbits.

Alkali burns are one of the most common injuries used in corneal wound healing studies. Investigators have used different conditions to produce corneal alkali injuries that have varied in sodium hydroxide concentration, application methods, and duration of exposure. A critical factor in the subsequent corneal healing responses, including myofibroblast generation and fibrosis localization, is whether, or not, Descemet's membrane and the endothelium are injured during the initial exposure.

Losartan Inhibition of Myofibroblast Generation and Late Haze (Scarring Fibrosis) After PRK in Rabbits.

Purpose: To study the effect of topical losartan compared to vehicle on the generation of myofibroblasts and development of late haze scarring fibrosis after photorefractive keratectomy (PRK) in rabbits.

Methods: Twelve rabbits had -9.00 diopter (D) PRK in one eye followed by 50 µL of topical 0.

Early LASIK flap displacement without signs of infection.

A 37-year-old woman was referred for refractive surgery evaluation. Poor visual quality in her left eye is her chief concern. The patient had undergone laser in situ keratomileusis (LASIK) in both eyes 3 days previously.

Topical Losartan and Corticosteroid Additively Inhibit Corneal Stromal Myofibroblast Generation and Scarring Fibrosis After Alkali Burn Injury.

Purpose: To evaluate the efficacy of losartan and prednisolone acetate in inhibiting corneal scarring fibrosis after alkali burn injury in rabbits.

Methods: Sixteen New Zealand White rabbits were included. Alkali injuries were produced using 1N sodium hydroxide on a 5-mm diameter Whatman #1 filter paper for 1 minute.

Corneal fibroblast collagen type IV negative feedback modulation of TGF beta: A fibrosis modulating system likely active in other organs.

Collagen type IV (COL IV) is a major component of basement membranes (BM) in all organs. It serves functions related to BM organization and modulates the passage of growth factors from one tissue compartment to another. COL IV binds transforming growth factor (TGF) beta-1 and TGF beta-2 and, therefore, is a major modulator of TGF beta pro-fibrotic functions.

Topical losartan inhibits corneal scarring fibrosis and collagen type IV deposition after Descemet's membrane-endothelial excision in rabbits.

The purpose of this study was to examine the effect of topical and/or oral angiotensin converting enzyme II inhibitor and TGF-beta signaling blocker losartan on corneal stromal fibrosis that developed in rabbit corneas after Descemetorhexis removal of central Descemet's membrane and corneal endothelium. Twenty-eight New Zealand white rabbits were included and either had 8 mm central Descemetorhexis or sham control surgery without Descemetorhexis in one eye. Groups of 4 eyes without Descemetorhexis were treated for one month with no medications, topical losartan or oral losartan.

Corneal Opacity: Cell Biological Determinants of the Transition From Transparency to Transient Haze to Scarring Fibrosis, and Resolution, After Injury.

Purpose: To highlight the cellular, matrix, and hydration changes associated with opacity that occurs in the corneal stroma after injury.

Methods: Review of the literature.

Results: The regulated transition of keratocytes to corneal fibroblasts and myofibroblasts, and of bone marrow-derived fibrocytes to myofibroblasts, is in large part modulated by transforming growth factor beta (TGFβ) entry into the stroma after injury to the epithelial basement membrane (EBM) and/or Descemet's membrane.

Epithelial Basement Membrane Regeneration After PRK-Induced Epithelial-Stromal Injury in Rabbits: Fibrotic Versus Non-fibrotic Corneal Healing.

Purpose: To study epithelial basement membrane (EBM) regeneration in non-fibrotic and fibrotic corneas after photorefractive keratectomy (PRK).

Methods: Rabbits (120 total) had either epithelial scrape alone, -4.50 diopters (D) PRK, -9.

Descemet's membrane injury and regeneration, and posterior corneal fibrosis, in rabbits.

The purpose of this investigation was to study Descemet's membrane and corneal endothelial regeneration, myofibroblast generation and disappearance, and TGF beta-1 localization after Descemet's membrane-endothelial excision (Descemetorhexis) in rabbits. Thirty-six rabbits had 8 mm Descemetorhexis and standardized slit lamp photos at 1, 2 and 4 days, 1, 2 and 4 weeks, and 2, 4 and 6 months, as well as multiplex IHC for stromal cell markers keratocan, vimentin, and alpha-smooth muscle actin (SMA); basement membrane (BM) components perlecan, nidogen-1, laminin alpha-5, and collagen type IV; and corneal endothelial marker Na,K-ATPase β1, and TGF beta-1, with ImageJ quantitation. Stromal transparency increased from the periphery beginning at two months after injury and progressed into the central cornea by six months.

TGFβ1 and TGFβ2 proteins in corneas with and without stromal fibrosis: Delayed regeneration of apical epithelial growth factor barrier and the epithelial basement membrane in corneas with stromal fibrosis.

The purpose of this study was to investigate the expression and localization of transforming growth factor (TGF) β1 and TGFβ2 in rabbit corneas that healed with and without stromal fibrosis, and to further study defective perlecan incorporation in the epithelial basement membrane (EBM) in corneas with scarring fibrosis. A total of 120 female rabbits had no surgery, -4.5D PRK, or -9D PRK.

Fibroblastic and bone marrow-derived cellularity in the corneal stroma.

The unwounded, normal corneal stroma is a relatively simple, avascular tissue populated with quiescent keratocytes, along with corneal nerves and a few resident dendritic and monocyte/macrophage cells. In the past, the resting keratocytes were thought of as a homogenous cellular population, but recent work has shown local variations in vimentin and nestin expression, and responsiveness to transforming growth factor (TGF)-β1. Studies have also supported there being "stromal stem cells" in localized areas.