The Ocular Surface
, Pages 27-36
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Bioactive substrates can be used therapeutically to enhance wound healing. Here, we evaluated the effect of an in-situ thermoresponsive hydrogel from decellularized porcine cornea ECM, COMatrix (COrnea Matrix), for application as an ocular surface bandage for corneal epithelial defects.
COMatrix hydrogel was fabricated from decellularized porcine corneas. The effects of COMatrix hydrogel on attachment and proliferation of human corneal epithelial cells (HCECs) were evaluated in vitro. The effect of COMatrix on the expressions of the inflammatory genes, IL-1β, TNF-α, and IL-6 was assessed by RT-PCR. The in-situ application and also repairing effects of COMatrix hydrogel as an ocular bandage was studied in a murine model of corneal epithelial wound. The eyes were examined by optical coherence tomography (OCT) and slit-lamp microscopy in vivo and by histology and immunofluorescence post-mortem.
In vitro, COMatrix hydrogel significantly enhanced the attachment and proliferation of HCECs relative to control. HCECs exposed to COMatrix had less induced expression of TNF-α (P<0.05). In vivo, COMatrix formed a uniform hydrogel that adhered to the murine ocular surface after in-situ curing. Corneal epithelial wound closure was significantly accelerated by COMatrix hydrogel compared to control (P<0.01). There was significant increase in the expression of proliferation marker Ki-67 in wounded corneal epithelium by COMatrix hydrogel compared to control (P<0.05).
COMatrix hydrogel is a naturally derived bioactive material with potential application as an ocular surface bandage to enhance epithelial wound healing.
The stratified non-keratinized squamous epithelium of the cornea plays a critical role in preserving corneal function by providing a barrier against environmental damage and inhibiting angiogenesis and modulating immune response . The corneal epithelium is dynamically rejuvenated following normal shedding of superficial cells or epithelial wounds due to trauma or infections. Corneal epithelial regeneration is orchestrated and regulated by many factors including cross-talk between corneal cells, immune cells, extracellular matrix (ECM) and secreted factors (e.g. growth factors) [2,3].
Many studies have shown the corneal epithelial restorative effects of growth factors such as epidermal growth factor (EGF), nerve growth factor (NGF) and hepatocyte growth factors (HGF), as well as secretomes from mesenchymal stem cells and extracellular-matrix (ECM)-rich scaffolds such as amnion [, , , , , , ]. Other groups have pursued the application of in-situ chemically cross-linked natural biomaterials such as collagen and hyaluronic acid for regeneration of corneal stroma and epithelium [, , ]. While there are several reports on the use of processed decellularized ECMs for focal corneal stromal regeneration [, , , ], the potential of corneal ECM hydrogel for enhancing the corneal epithelial wound repair as an ocular bandage, has not been studied. Processed (partially-digested) decellularized ECMs have been fabricated from several tissues including urinary bladder, heart, intestine, brain, testis, bone, cartilage, tendon, conjunctiva, and adipose tissue [, , ]. Processed ECMs not only possess regenerative effects, but also readily form in-situ thermoresponsive hydrogels with no further manipulations. We recently characterized the rheological behavior and the protein composition of a thermoresponsive hydrogel fabricated from decellularized porcine cornea ECM .
Cornea-derived ECM hydrogel can potentially enhance wound healing as an ocular bandage by providing a protective barrier that simultaneously provides factors to promote epithelial regeneration . In this study, we evaluated the healing potential of fabricated in-situ thermoresponsive hydrogel, COMatrix (COrneal Matrix) from decellularized porcine cornea, as an ocular bandage to promote healing of corneal epithelial wounds. We investigated the effects of COMatrix hydrogel on attachment, proliferation, and inflammatory responses of human corneal epithelial cells (HCECs) in vitro while providing proof of concept application of COMatrix hydrogel as an in-situ ocular surface bandage in a murine model of corneal epithelial wound healing.
Fabrication of COMatrix ocular bandage hydrogel
Fresh intact porcine eyeballs were obtained from a certified abattoir (Park Packing Co. Inc., Chicago, IL). Under sterile conditions, the porcine corneas (PCs) were dissected and washed with Phosphate Buffered Saline (PBS, 1x) containing 1% gentamicin, 1% penicillin and 1% streptomycin.
The decellularization process for PCs were performed as described before with some modifications . The PCs were cut into pieces with an average size of 2×2 mm2. The tissue pieces were first stirred in 20mM
COMatrix hydrogel enhances attachment and proliferation of HCECs and attenuates TNF-α expression
The fabricated COMatrix hydrogel before and after thermal (heat) gelation and its transparency are shown in Fig. 1B. The bioactivity of COMatrix hydrogel was evaluated using in-vitro attachment, proliferation, and inflammatory cytokine induction assays on human corneal epithelial cells. To assess the interaction of human corneal epithelial cells with COMatrix, the attachment of cells to plates coated with hydrogel was compared to uncoated control plates (Fig. 2A). Microscopic observation of
In this study, an in-situ thermoresponsive and transparent ocular bandage hydrogel, COMatrix, was fabricated for application to the ocular surface to promote regeneration of the corneal epithelium. The induction of cell proliferation by COMatrix hydrogel was shown in-vitro, followed by a proof of concept application as an ocular surface bandage in a murine corneal epithelial wound healing model.
Corneal epithelial wound healing is a dynamic process involving proliferation, migration, adhesion,
In this study, an in-situ thermoresponsive and transparent ocular bandage hydrogel, COMatrix, was fabricated from decellularized porcine cornea ECM as a regenerative biomaterial for corneal epithelial repair. The in-vitro and in-vivo experiments have shown the corneal epithelial regenerative effects of COMatrix hydrogel which provide proof of concept and potential for clinical translation. COMatrix hydrogel is a promising biomaterial which can potentially be used as an easy-to-apply ocular
This work was supported by R01 EY024349 (ARD), Core Grant for Vision Research EY01792 (MIR) from NEI/NIH; Unrestricted Grant to the Department and Physician-Scientist Award both from Research to Prevent Blindness; Eversight.
The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Commercial relationships disclosures
The authors have no commercial disclosure related to this work.
The authors would like to appreciate Lauren Kalinoski for the illustrations.
This study is extracted from PhD dissertation of G.Y.
- J.A. Rada et al.
Regulation of corneal collagen fibrillogenesis in vitro by corneal proteoglycan (lumican and decorin) core proteins
Exp Eye Res
- L.R. Katzman et al.
Management strategies for persistent epithelial defects of the cornea
Saudi J Ophthalmol
- M.K. Kim et al.
Current status of corneal xenotransplantation
Int J Surg
- J. Parkinson et al.
Simple physical model of collagen fibrillogenesis based on diffusion limited aggregation
J Mol Biol
- T. Yadavalli et al.
Prior inhibition of AKT phosphorylation by BX795 can define a safer strategy to prevent herpes simplex virus-1 infection of the eye
- J. Witt et al.
Decellularized porcine conjunctiva as an alternative substrate for tissue-engineered epithelialized conjunctiva
- L.T. Saldin et al.
Extracellular matrix hydrogels from decellularized tissues: structure and function
- F. Wang et al.
Decellularized porcine cornea-derived hydrogels for the regeneration of epithelium and stroma in focal corneal defects
- F. Chen et al.
Bio-orthogonally crosslinked hyaluronate-collagen hydrogel for suture-free corneal defect repair
- Q. Le et al.
The application of human amniotic membrane in the surgical management of limbal stem cell deficiency
Corneal stromal wound healing: major regulators and therapeutic targets
Phase II randomized, double-masked, vehicle-controlled trial of recombinant human nerve growth factor for neurotrophic keratitis
Growth factors and corneal epithelial wound healing
Brain Res Bull
Progress in corneal wound healing
Prog Retin Eye Res
The impact of hyperglycemia on the corneal epithelium: molecular mechanisms and insight
Strategies for reconstructing the limbal stem cell niche
Limbal and corneal epithelial homeostasis
Curr Opin Ophthalmol
Corneal epithelial wound healing
Exp Biol Med
Corneal wound healing effects of mesenchymal stem cell secretome delivered within a viscoelastic gel carrier
Stem Cells Transl Med
Simultaneous interpenetrating polymer network of collagen and hyaluronic acid as an in situ-forming corneal defect filler
In situ-forming collagen hydrogel crosslinked via multi-functional PEG as a matrix therapy for corneal defects
Shear-induced alignment of collagen fibrils using 3D cell printing for corneal stroma tissue engineering
Characterization of cornea-specific bioink: high transparency, improved in vivo safety
J Tissue Eng
Early observation of extracellular matrix-derived hydrogels for corneal stroma regeneration
Tissue Eng C Methods
Solubilized extracellular matrix bioscaffolds derived from diverse source tissues differentially influence macrophage phenotype
J Biomed Mater Res
Therapeutic effects of lyophilized conditioned-medium derived from corneal mesenchymal stromal cells on corneal epithelial wound healing
Curr Eye Res
Down-regulation of Notch signaling during corneal epithelial proliferation
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Dual-crosslinked regenerative hydrogel for sutureless long-term repair of corneal defect
2023, Bioactive Materials
Corneal transplantation is the most effective clinical treatment for corneal defects, but it requires precise size of donor corneas, surgical sutures, and overcoming other technical challenges. Postoperative patients may suffer graft rejection and complications caused by sutures. Ophthalmic glues that can long-term integrate with the corneal tissue and effectively repair the focal corneal damage are highly desirable. Herein, a hybrid hydrogel consisting of porcine decellularized corneal stroma matrix (pDCSM) and methacrylated hyaluronic acid (HAMA) was developed through a non-competitive dual-crosslinking process. It can be directly filled into corneal defects with various shapes. More importantly, through formation of interpenetrating network and stable amide bonds between the hydrogel and adjacent tissue, the hydrogel manifested excellent adhesion properties to achieve suture-free repair. Meanwhile, the hybrid hydrogel not only preserved bioactive components from pDCSM, but also exhibited cornea-matching transparency, low swelling ratio, slow degradation, and enhanced mechanical properties, which was capable of withstanding superhigh intraocular pressure. The combinatorial hydrogel greatly improved the poor cell adhesion performance of HAMA, supported the viability, proliferation of corneal cells, and preservation of keratocyte phenotype. In a rabbit corneal stromal defect model, the experimental eyes treated with the hybrid hydrogel remained transparent and adhered intimately to the stroma bed with long-term retention, accelerated corneal re-epithelialization and wound healing. Giving the advantages of high bioactivity, low-cost, and good practicality, the dual-crosslinked hybrid hydrogel served effectively for long-term suture-free treatment and tissue regeneration after corneal defect.
Functionalized hydrogels in ophthalmic applications: Ocular inflammation, corneal injuries, vitreous substitutes and intravitreal injection
2022, Materials and Design
With the prevalence of eye diseases, such as inflamed eyes, corneal injury, cataract, glaucoma, and retinal degenerative diseases, different clinical strategies have been developed, however, they still suffer from many inevitable drawbacks in practical applications. Functionalized hydrogels have emerged as attractive materials and revolutionary strategies for ophthalmic applications owing to their favorable properties, such as excellent biocompatibility, near-physiological extracellular matrix environment, injectability, tailorable structure, inherent flexibility, dynamically adjustable mechanical properties, particularly attractive self-adhesion, enviable cell delivery, and sustained drug release capabilities. In this review, various functionalized hydrogels for different ophthalmic diseases have been comprehensively summarized. The review also systematically introduces the advanced research progress in ophthalmic applications, including topical administration for superficial inflamed eyes, dressings for corneal injuries, injectable drug delivery system for glaucomatous optic neuropathy, vitreous substitutes after vitrectomy, intravitreal administration for intraocular diseases, and etc. Finally, the scientific challenges and untapped potential are expounded to demonstrate the future prospects of engineered hydrogels for the treatment of ocular diseases. The review aims to provide comparative perspectives and multifaceted insights to inspire more in-depth research on hydrogels and provide guidance for their varied applications in ophthalmology.
Decellularized extracellular matrix: New promising and challenging biomaterials for regenerative medicine
Extracellular matrix is rich in biomolecules including structural proteins, glycosaminoglycans, and small molecules that are important for the maintenance and repair of tissue. Decellularized extracellular matrix (dECM) is expected to retain these key biomolecules and makes it a promising biomaterial candidate for regenerative medicine applications. To date, dECM-particle based biomaterials have been developed to engineer over 15 tissue types or organs, with the ultimate goal of mimicking specific biological and physical properties of the native tissue. The most common scaffold types are injectable hydrogels, electrospun scaffolds and bioprinted scaffolds. The purpose of this review paper is to highlight key challenges, fabrication methods and progress made for each tissue type, along with the discussion of other elements that are integral to push dECM biomaterials towards effective and specialized tissue repair.
Critical media attributes in E-beam sterilization of corneal tissue
2022, Acta Biomaterialia
When ionizing irradiation interacts with a media, it can form reactive species that can react with the constituents of the system, leading to eradication of bioburden and sterilization of the tissue. Understanding the media's properties such as polarity is important to control and direct those reactive species to perform desired reactions. Using ethanol as a polarity modifier of water, we herein generated a series of media with varying relative polarities for electron beam (E-beam) irradiation of cornea at 25 kGy and studied how the irradiation media's polarity impacts properties of the cornea. After irradiation of corneal tissues, mechanical (tensile strength and modulus, elongation at break, and compression modulus), chemical, optical, structural, degradation, and biological properties of the corneal tissues were evaluated. Our study showed that irradiation in lower relative polarity media improved structural properties of the tissues yet reduced optical transmission; higher relative polarity reduced structural and optical properties of the cornea; and intermediate relative polarity (ethanol concentrations=20-30% (v/v)) improved the structural properties, without compromising optical characteristics. Regardless of media polarity, irradiation did not negatively impact the biocompatibility of the corneal tissue. Our data shows that the absorbed ethanol can be flushed from the irradiated cornea to levels that are nontoxic to corneal and retinal cells. These findings suggest that the relative polarity of the irradiation media can be tuned to generate sterilized tissues, including corneal grafts, with engineered properties that are required for specific biomedical applications.
Extending the shelf-life of corneal tissue can improve general accessibility of cornea grafts for transplantation. Irradiation of donor corneas with E-beam is an emerging technology to sterilize the corneal tissues and enable their long-term storage at room temperature. Despite recent applications in clinical medicine, little is known about the effect of irradiation and preservation media's characteristics, such as polarity on the properties of irradiated corneas. Here, we have showed that the polarity of the media can be a valuable tool to change and control the properties of the irradiated tissue for transplantation.
Supramolecular host-guest hyaluronic acid hydrogels enhance corneal wound healing through dynamic spatiotemporal effects
2022, Ocular Surface
Severe corneal wounds can lead to ulceration and scarring if not promptly and adequately treated. Hyaluronic acid (HA) has been investigated for the treatment of corneal wounds due to its remarkable biocompatibility, transparency and mucoadhesive properties. However, linear HA has low retention time on the cornea while many chemical moieties used to crosslink HA can cause toxicity, which limits their clinical ocular applications. Here, we used supramolecular non-covalent host-guest interactions between HA-cyclodextrin and HA-adamantane to form shear-thinning HA hydrogels and evaluated their impact on corneal wound healing. Supramolecular HA hydrogels facilitated adhesion and spreading of encapsulated human corneal epithelial cells ex vivo and improved corneal wound healing in vivo as an in situ-formed, acellular therapeutic membrane. The HA hydrogels were absorbed within the corneal stroma over time, modulated mesenchymal cornea stromal cell secretome production, reduced cellularity and inflammation of the anterior stroma, and significantly mitigated corneal edema compared to treatment with linear HA and untreated control eyes. Taken together, our results demonstrate supramolecular HA hydrogels as a promising and versatile biomaterial platform for corneal wound healing.
Preparation and biological evaluation of decellularized dermal matrix hydrogel
2023, Chinese Journal of Tissue Engineering Research
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To evaluate long-term anatomical and functional outcomes of the MICOF keratoprosthesis to treat end-stage corneal blindness.
Retrospective review of consecutive clinical case series.
Between October 2000 and October 2015, at the Department of Ophthalmology of Chinese PLA General Hospital (PLAGH), a total of 132 eyes of 131 patients had undergone a MICOF keratoprosthesis implantation. Of those, 91 eyes of 90 patients were included in this study.
Preoperative information, surgical procedures, and postoperative data were collected for each included eye.
Best-corrected visual acuity (BCVA), keratoprosthesis retention, and significant postoperative complications were reported.
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All patbients had a preoperative visual acuity of hand motions or worse. A MICOF keratoprosthesis significantly improved patients' visual function with bilateral end-stage corneal blindness. Postoperative visual acuity improved to 20/200 or better in 41 eyes (45.1%, of 91 eyes) and to 20/100 or better in 32 eyes (35.2% of 91 eyes) at the last follow-up visit. Preexisting glaucoma was present in 17 (18.7% of 91 eyes). The most common postoperative complications were overgrowth of the surface mucosa (31.9%, 29 of 91 eyes), glaucoma (25.3%, 23 of 91 eyes), retro-prosthetic membrane (15.4%, 14 of 91 eyes), keratoprosthesis device extrusion (15.4%, 14 of 91 eyes), superficial tissue thinning (14.3%, 13 of 91 eyes), endophthalmitis (13.2%, 12 of 91 eyes), titanium frame exposure (13.2%, 12 of 91 eyes), optical cylinder ante-displacement (13.2%, 12 of 91 eyes), cornea melting (7.7%, 7 of 91 eyes), retinal detachment (6.6%, 6 of 91 eyes) and aqueous humour leakage (2.2%, 2 of 91 eyes). 84.6% (77 of 91 eyes) of the eyes retained their initial keratoprosthesis at the latest follow-up.
A MICOF keratoprosthesis is a reliable approach to rescue vision in end-stage corneal blinded patients and has better retention than a Boston Kpro TypeⅡ.
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Human meibum and tear film derived (O-acyl)-omega-hydroxy fatty acids in meibomian gland dysfunction
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The molecular basis of the tear film and lipid layer alterations in meibomian gland dysfunction (MGD) is unknown. This study aimed to identify and compare (O-acyl)-omega-hydroxy fatty acids (OAHFAs) derived from human meibum and tears in MGD.
Of 195 eligible subjects (18–84 years, 62.6% female), 183 and 174 provided samples for tears and meibum, respectively. Subjects were classified into four groups: Normal, Asymptomatic MGD, MGD, and Mixed. Samples from the right eye of each subject were infused into the SCIEX 5600 TripleTOF mass spectrometer in negative ion mode. Lipid intensities identified with Analyst1.7TF and SCIEX LipidView1.3 were normalized by an internal standard and total ion current, then statistically compared in MetaboAnalyst 4.0.
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Chronic ocular complications in lamotrigine vs. trimethoprim-sulfamethoxazole induced Stevens-Johnson syndrome/toxic epidermal necrolysis
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The purpose of this study is to compare the severity of chronic ocular complications of Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) induced by lamotrigine (LT) vs. trimethoprim-sulfamethoxazole (TS).
This retrospective cross-sectional study evaluated all SJS/TEN patients treated within our hospital network from 2008 to 2018. Inclusion criteria included patients with reactions identified as caused by either LT or TS, and patients with at least one ophthalmology follow up in the chronic phase (≥3 months from disease onset). Primary outcome measures included LogMAR best-corrected VA at most recent visit and the presence or absence of severe ocular complications (SOC). Secondary outcome measures included chronic ocular complication severity scores using a modified Sotozono scoring system.
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