An in vitro 3-dimensional Collagen-based Corneal Construct with Innervation Using Human Corneal Cell Lines.

Purpose: To develop a 3-dimensional corneal construct suitable for in vitro studies of disease conditions and therapies. Design: In vitro human corneal constructs were created using chemically crosslinked collagen and chondroitin sulfate extracellular matrix and seeded with 3 human corneal cell types (epithelial, stromal, and endothelial) together with neural cells. The neural cells were derived from hybrid neuroblastoma cells and the other cells used from immortalized human corneal cell lines. To check the feasibility and characterize the constructs, cytotoxicity, cell proliferation, histology, and protein expression studies were performed. Results: Optimized culture condition permitted synchronized viability across the cell types within the construct. The construct showed a typical appearance for different cellular layers, including healthy appearing, phenotypically differentiated neurons. The expected protein expression profiles for specific cell types within the construct were confirmed with western blotting. Conclusions: An in vitro corneal construct was successfully developed with maintenance of individual cell phenotypes with anatomically correct cellular loci. The construct may be useful in evaluation of specific corneal disorders and in developing different corneal disease models. Additionally, the construct can be used in evaluating drug targeting and/or penetration to individual corneal layers, testing novel therapeutics for corneal diseases, and potentially reducing the necessity for animals in corneal research at the early stages of investigation. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Inflammation-suppressing cornea-in-a-syringe with anti-viral GF19 peptide promotes regeneration in HSV-1 infected rabbit corneas.

Pathophysiologic inflammation, e.g., from HSV-1 viral infection, can cause tissue destruction resulting in ulceration, perforation, and ultimately blindness. We developed an injectable Cornea-in-a-Syringe (CIS) sealant-filler to treat damaged corneas. CIS comprises linear carboxylated polymers of inflammation-suppressing 2-methacryloyloxyethyl phosphorylcholine, regeneration-promoting collagen-like peptide, and adhesive collagen-citrate glue. We also incorporated GF19, a modified anti-viral host defense peptide that blocked HSV-1 activity in vitro when released from silica nanoparticles (SiNP-GF19). CIS alone suppressed inflammation when tested in a surgically perforated and HSV-1-infected rabbit corneal model, allowing tissue and nerve regeneration. However, at six months post-operation, only regenerated neocorneas previously treated with CIS with SiNP-GF19 had structural and functional features approaching those of normal healthy corneas and were HSV-1 virus-free. We showed that composite injectable biomaterials can be designed to allow regeneration by modulating inflammation and blocking viral activity in an infected tissue. Future iterations could be optimized for clinical application.

Successful restoration of corneal surface integrity with a tissue-engineered allogeneic implant in severe keratitis patients.

OBJECTIVES: Corneal diseases are among the main causes of blindness, with approximately 4.6 and 23 million patients worldwide suffering from bilateral and unilateral corneal blindness, respectively. The standard treatment for severe corneal diseases is corneal transplantation. However, relevant disadvantages, particularly in high-risk conditions, have focused the attention on the search for alternatives. METHODS: We report interim findings of a phase I-II clinical study evaluating the safety and preliminary efficacy of a tissue-engineered corneal substitute composed of a nanostructured fibrin-agarose biocompatible scaffold combined with allogeneic corneal epithelial and stromal cells (NANOULCOR). 5 subjects (5 eyes) suffering from trophic corneal ulcers refractory to conventional treatments, who combined stromal degradation or fibrosis and limbal stem cell deficiency, were included and treated with this allogeneic anterior corneal substitute. RESULTS: The implant completely covered the corneal surface, and ocular surface inflammation decreased following surgery. Only four adverse reactions were registered, and none of them were severe. No detachment, ulcer relapse nor surgical re-interventions were registered after 2 years of follow-up. No signs of graft rejection, local infection or corneal neovascularization were observed either. Efficacy was measured as a significant postoperative improvement in terms of the eye complication grading scales. Anterior segment optical coherence tomography images revealed a more homogeneous and stable ocular surface, with complete scaffold degradation occurring within 3-12 weeks after surgery. CONCLUSIONS: Our findings suggest that the surgical application of this allogeneic anterior human corneal substitute is feasible and safe, showing partial efficacy in the restoration of the corneal surface.

Harmonizing ophthalmic residency surgical training across Europe: A proposed surgical curriculum.

BACKGROUND: One of the core aims of the European Union of Medical Specialists is to harmonize training across Europe by creating European Training Requirements for all medical specialties including Ophthalmology. The theoretical part is already defined by the EBO, however as ophthalmology also includes surgical skills, we herein propose a surgical minimum curriculum for ophthalmology residents in Europe. METHODS: National and international ophthalmic training curricula which are publicly available in English were reviewed and compared. The final proposal was created from 5 criteria: 1. Disease prevalence; 2. Patient safety; 3. Case-trainee ratio; 4. Skill transfer; and 5. Technical difficulty. RESULTS: In total 7 different training curricula from across the world were compared. Among the surgical procedures, cataract surgery has the highest median number of procedures required to be completed during residency: 86 procedures (50-350). Followed by oculoplastics: 28 procedures (10-40) and panretinal photocoagulation: 27.5 procedures (10-49) Full procedural competence is proposed in 9 surgical skills, including YAG laser posterior capsulotomy, retinal argon laser, intravitreal injection, corneal foreign body removal, removal of corneal sutures, facial and periocular laceration repair, eyelid laceration repair, minor eyelid procedures, and punctal occlusion. These procedures are deemed essential and feasible for all ophthalmology residents in Europe to perform independently upon completion of their training. CONCLUSION: This proposal should be regarded as a recommendation based on comparable surgical curricula in use worldwide to establish standards across European countries and may serve as valuable insight to those responsible for compiling ETRs for ophthalmology, or their national curriculums.

Treatment of neovascular age-related macular degeneration within 48 h from diagnosis improves long-term functional outcome.

PURPOSE: To evaluate long-term visual and anatomical outcomes in neovascular age-related macular degeneration (nAMD) patients treated with anti-vascular endothelial growth factor (VEGF) agents depending on the time delay from confirmed diagnosis to treatment initiation. MATERIALS AND METHODS: Seventy-three nAMD patients (73 eyes) treated with anti-VEGF agents for 12 months using the pro re nata regimen were included in this retrospective longitudinal study. Patients were split into 3 groups according to the time from diagnosis to first anti-VEGF injection: < 48 h (group 1); 48 h-7 days (group 2); > 7 days (group 3). Decimal best-corrected visual acuity (VA) and macular thickness (MT) were recorded at baseline and 1-2-, 3-4-, 6- and 12-month later. Furthermore, age, gender as well as the applied treatment and number of injections after 12 months of treatment were also registered and compared. RESULTS: Long-term effect of the treatment demonstrated enhanced VA in group 1 patients compared with the rest of groups after 1-2-, 6-, and 12-month follow-up (P < 0.05). Positive effects of early treatment were additionally corroborated by the augmented percentage of patients with normal VA in the group 1 respect to the rest of groups over studied time points (P < 0.05). Moreover, the VA gain in nAMD at group 1 was obtained with a mean of 3.7 intravitreal injections over 1-year follow-up period. Regarding MT, non-significant difference was observed among groups. CONCLUSIONS: An early initial treatment with VEGF inhibitors is critical to achieve the best functional benefits of this therapy in new-onset nAMD patients.

Comparative analysis of European residency programs: benchmarking and harmonizing ophthalmology training in Europe.

BACKGROUND/OBJECTIVES: This study aims to benchmark the training programs of European ophthalmology residents. SUBJECTS/METHODS: An online survey, aimed at European ophthalmology residents in training and those within two years of completion, was sent through the national representatives of the European Society of Ophthalmology, Young Ophthalmologists section (SOE-YO). The study involved 214 subjects representing 36 of the 44 European countries offering ophthalmology training programs. RESULTS: Among the surveyed, 74.8% of participants had an official national curriculum; 55.8% had a national specialty examination to accredit their training as ophthalmologists. 45.8% were satisfied or very satisfied with the clinical skills acquired, while 42.1% were completely dissatisfied with the surgical skills achieved. Considering the 4th year residents (mean duration of the residency), many of them did not perform phacoemulsification surgery (34%), pterygium excision (46.9%), or repair of eyelid laceration (31.3%). CONCLUSIONS: There is great heterogeneity in the competencies achieved by residents in training according to their country of origin, especially in terms of surgical competences.

Survey of Ophthalmology Training Experiences Among Young Ophthalmologists in the Asia-Pacific.

PURPOSE: To describe ophthalmology training experiences across the Asia-Pacific (APAC). DESIGN: Survey study. METHODS: We utilized an anonymous online survey, which was previously validated and conducted in Europe, through Young Ophthalmologist leaders from the national member societies of the Asia-Pacific Academy of Ophthalmology (APAO) from September 2019 to July 2021. Responses were based on a 5-point Likert scale (where applicable) and data were analyzed using Microsoft Excel. Our main outcome measures were differences between regions, that is, Southeast Asia (SEA) and Western Pacific (WP); and seniority, that is, trainees/junior ophthalmologists and senior ophthalmologists. RESULTS: We collated 130 responses representing 20 regions in the APAC region. The year of completion of ophthalmic training ranged from 1999 to 2024. The mean duration of training was 3.7±1.0 years. Most (98/130, 75%) indicated an interest for a common training standard across the APAC. Comparing SEA and WP trainees, both regions had similar working environments, but those in SEA reported significantly lower remuneration than their counterparts in WP ($600 vs $3000, P <0.05). WP trainees performed more phacoemulsification surgeries (76 WP vs 19 SEA), while SEA trainees conducted more manual small incision cataract surgeries (157 WP vs 1.5 SEA per duration of training). Senior ophthalmologists performed more cataract surgeries (210.9 senior ophthalmologists vs 40.1 junior ophthalmologists). Trainees had less confidence in medical competency areas such as interpreting an electroretinogram/visual evoked potential/electrooculogram (SEA=1.8, WP=2.1) and conducting an angiography (SEA=2.8, WP=3.4). CONCLUSIONS: Our study highlighted heterogeneity among ophthalmology training experiences in the APAC region, with the majority indicating an interest in a common training standard.

Novel Treatments for Age-Related Macular Degeneration: A Review of Clinical Advances in Sustained Drug Delivery Systems.

In recent years, the number of patients with ocular diseases is increasing as a consequence of population aging. Among them, one of the most common is the age-related macular degeneration (AMD), a condition that leads to vision loss if it is not treated. AMD is a multifactorial disorder with two advanced forms, dry and neovascular AMD. Currently, although there is no approved therapy that significantly impacts dry AMD progression, several pharmacologic therapies exist for neovascular AMD. Notwithstanding, evidence suggests a suboptimal result in a high number of patients receiving these therapeutic options. Consequently, finding effective strategies is not only a still unmet medical need in dry AMD but also in neovascular AMD. This underlines the need for new drug delivery technologies that can improve the pharmacological action and drug concentration at the target sites. In this regard, sustained drug delivery systems are presented as the most promising therapeutic options in AMD patients. This review summarized the pathogenesis and the current treatment options for AMD, focusing on the emerging ocular sustained drug delivery approaches undergoing clinical trials.

Torsional wave elastography to assess the mechanical properties of the cornea.

Corneal mechanical changes are believed to occur before any visible structural alterations observed during routine clinical evaluation. This study proposed developing an elastography technique based on torsional waves (TWE) adapted to the specificities of the cornea. By measuring the displacements in the propagation plane perpendicular to the axis of the emitter, the effect of guided waves in plate-like media was proven negligible. Ex vivo experiments were carried out on porcine corneal samples considering a group of control and one group of alkali burn treatment ([Formula: see text]OH) that modified the mechanical properties. Phase speed was recovered as a function of intraocular pressure (IOP), and a Kelvin-Voigt rheological model was fitted to the dispersion curves to estimate viscoelastic parameters. A comparison with uniaxial tensile testing with thin-walled assumptions was also performed. Both shear elasticity and viscosity correlated positively with IOP, being the elasticity lower and the viscosity higher for the treated group. The viscoelastic parameters ranged from 21.33 to 63.17 kPa, and from 2.82 to 5.30 Pa s, for shear elasticity and viscosity, respectively. As far as the authors know, no other investigations have studied this mechanical plane under low strain ratios, typical of dynamic elastography in corneal tissue. TWE reflected mechanical properties changes after treatment, showing a high potential for clinical diagnosis due to its rapid performance time and paving the way for future in vivo studies.

Critical media attributes in E-beam sterilization of corneal tissue.

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. STATEMENT OF SIGNIFICANCE: 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.

Optimization of Collagen Chemical Crosslinking to Restore Biocompatibility of Tissue-Engineered Scaffolds.

Collagen scaffolds, one of the most used biomaterials in corneal tissue engineering, are frequently crosslinked to improve mechanical properties, enzyme tolerance, and thermal stability. Crosslinkers such as 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC) are compatible with tissues but provide low crosslinking density and reduced mechanical properties. Conversely, crosslinkers such as glutaraldehyde (GTA) can generate mechanically more robust scaffolds; however, they can also induce greater toxicity. Herein, we evaluated the effectivity of double-crosslinking with both EDC and GTA together with the capability of sodium metabisulfite (SM) and sodium borohydride (SB) to neutralize the toxicity and restore biocompatibility after crosslinking. The EDC-crosslinked collagen scaffolds were treated with different concentrations of GTA. To neutralize the free unreacted aldehyde groups, scaffolds were treated with SM or SB. The chemistry involved in these reactions together with the mechanical and functional properties of the collagen scaffolds was evaluated. The viability of the cells grown on the scaffolds was studied using different corneal cell types. The effect of each type of scaffold treatment on human monocyte differentiation was evaluated. One-way ANOVA was used for statistical analysis. The addition of GTA as a double-crosslinking agent significantly improved the mechanical properties and enzymatic stability of the EDC crosslinked collagen scaffold. GTA decreased cell biocompatibility but this effect was reversed by treatment with SB or SM. These agents did not affect the mechanical properties, enzymatic stability, or transparency of the double-crosslinked scaffold. Contact of monocytes with the different scaffolds did not trigger their differentiation into activated macrophages. Our results demonstrate that GTA improves the mechanical properties of EDC crosslinked scaffolds in a dose-dependent manner, and that subsequent treatment with SB or SM partially restores biocompatibility. This novel manufacturing approach would facilitate the translation of collagen-based artificial corneas to the clinical setting.

Tuning gelatin-based hydrogel towards bioadhesive ocular tissue engineering applications.

Gelatin based adhesives have been used in the last decades in different biomedical applications due to the excellent biocompatibility, easy processability, transparency, non-toxicity, and reasonable mechanical properties to mimic the extracellular matrix (ECM). Gelatin adhesives can be easily tuned to gain different viscoelastic and mechanical properties that facilitate its ocular application. We herein grafted glycidyl methacrylate on the gelatin backbone with a simple chemical modification of the precursor, utilizing epoxide ring-opening reactions and visible light-crosslinking. This chemical modification allows the obtaining of an elastic protein-based hydrogel (GELGYM) with excellent biomimetic properties, approaching those of the native tissue. GELGYM can be modulated to be stretched up to 4 times its initial length and withstand high tensile stresses up to 1.95 MPa with compressive strains as high as 80% compared to Gelatin-methacryloyl (GeIMA), the most studied derivative of gelatin used as a bioadhesive. GELGYM is also highly biocompatible and supports cellular adhesion, proliferation, and migration in both 2 and 3-dimensional cell-cultures. These characteristics along with its super adhesion to biological tissues such as cornea, aorta, heart, muscle, kidney, liver, and spleen suggest widespread applications of this hydrogel in many biomedical areas such as transplantation, tissue adhesive, wound dressing, bioprinting, and drug and cell delivery.

Collagen analogs with phosphorylcholine are inflammation-suppressing scaffolds for corneal regeneration from alkali burns in mini-pigs.

The long-term survival of biomaterial implants is often hampered by surgery-induced inflammation that can lead to graft failure. Considering that most corneas receiving grafts are either pathological or inflamed before implantation, the risk of rejection is heightened. Here, we show that bioengineered, fully synthetic, and robust corneal implants can be manufactured from a collagen analog (collagen-like peptide-polyethylene glycol hybrid, CLP-PEG) and inflammation-suppressing polymeric 2-methacryloyloxyethyl phosphorylcholine (MPC) when stabilized with the triazine-based crosslinker 4-(4,6-Dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride. The resulting CLP-PEG-MPC implants led to reduced corneal swelling, haze, and neovascularization in comparison to CLP-PEG only implants when grafted into a mini-pig cornea alkali burn model of inflammation over 12 months. Implants incorporating MPC allowed for faster nerve regeneration and recovery of corneal sensation. CLP-PEG-MPC implants appear to be at a more advanced stage of regeneration than the CLP-PEG only implants, as evidenced by the presence of higher amounts of cornea-specific type V collagen, and a corresponding decrease in the presence of extracellular vesicles and exosomes in the corneal stroma, in keeping with the amounts present in healthy, unoperated corneas.

Combined blockade of complement C5 and TLR co-receptor CD14 synergistically inhibits pig-to-human corneal xenograft induced innate inflammatory responses.

Inadequate supplies of donor corneas have evoked an escalating interest in corneal xenotransplantation. However, innate immune responses contribute significantly to the mechanism of xenograft rejection. We hypothesized that complement component C5 and TLR co-receptor CD14 inhibition would inhibit porcine cornea induced innate immune responses. Therefore, we measured cytokine release in human blood, induced by three forms of corneal xenografts with or without inhibitors. Native porcine cornea (NPC) induced interleukins (IL-1ß, IL-2, IL-6, IL-8, IL-1ra), chemokines (MCP-1, MIP-1α, MIP-1ß) and other cytokines (TNF, G-CSF, INF-γ, FGF-basic). Decellularized (DPC) and gamma-irradiated cornea (g-DPC) elevated the release of those cytokines. C5-blockade by eculizumab inhibited all the cytokines except G-CSF when induced by NPC. However, C5-blockade failed to reduce DPC and g-DPC induced cytokines. Blockade of CD14 inhibited DPC-induced cytokines except for IL-8, MCP-1, MIP-1α, and G-CSF, while it inhibited all of them when induced by g-DPC. Combined blockade of C5 and CD14 inhibited the maximum number of cytokines regardless of the xenograft type. Finally, by using the TLR4 specific inhibitor Eritoran, we showed that TLR4 activation was the basis for the CD14 effect. Thus, blockade of C5, when combined with TLR4 inhibition, may have therapeutic potential in pig-to-human corneal xenotransplantation. STATEMENT OF SIGNIFICANCE: Bio-engineered corneal xenografts are on the verge of becoming a viable alternative to allogenic human-donor-cornea, but the host's innate immune response is still a critical barrier for graft acceptance. By overruling this barrier, limited graft availability would no longer be an issue for treating corneal diseases. We showed that the xenograft induced inflammation is initiated by the complement system and toll-like receptor activation. Intriguingly, the inflammatory response was efficiently blocked by simultaneously targeting bottleneck molecules in the complement system (C5) and the TLR co-receptor CD14 with pharmaceutical inhibitors. We postulate that a combination of C5 and CD14 inhibition could have a great therapeutic potential to overcome the immunologic barrier in pig-to-human corneal xenotransplantation.

Toward electron-beam sterilization of a pre-assembled Boston keratoprosthesis.

PURPOSE: To evaluate the effects of electron-beam (E-beam) irradiation on the human cornea and the potential for E-beam sterilization of Boston keratoprosthesis (BK) devices when pre-assembled with a donor cornea prior to sterilization. METHODS: Human donor corneas and corneas pre-assembled in BK devices were immersed in recombinant human serum albumin (rHSA) media and E-beam irradiated at 25 kGy. Mechanical (tensile strength and modulus, and compression modulus), chemical, optical, structural, and degradation properties of the corneal tissue after irradiation and after 6 months of preservation were evaluated. RESULTS: The mechanical evaluation showed that E-beam irradiation enhanced the tensile and compression moduli of human donor corneas, with no impact on their tensile strength. By chemical and mechanical analysis, E-beam irradiation caused a minor degree of crosslinking between collagen fibrils. No ultrastructural changes due to E-beam irradiation were observed. E-beam irradiation slightly increased the stability of the cornea against collagenase-induced degradation and had no impact on glucose diffusion. The optical evaluation showed transparency of the cornea was maintained. E-beam irradiated corneal tissues and BK-cornea pre-assembled devices were stable for 6 months after room-temperature preservation. CONCLUSIONS: E-beam irradiation generated no detrimental effects on the corneal tissues or BK-cornea pre-assembled devices and improved native properties of the corneal tissue, enabling prolonged preservation at room temperature. The pre-assembly of BK in a donor cornea, followed by E-beam irradiation, offers the potential for an off-the-shelf, ready to implant keratoprosthesis device.

Electron Beam Sterilization of Poly(Methyl Methacrylate)-Physicochemical and Biological Aspects.

Electron beam (E-beam) irradiation is an attractive and efficient method for sterilizing clinically implantable medical devices made of natural and/or synthetic materials such as poly(methyl methacrylate) (PMMA). As ionizing irradiation can affect the physicochemical properties of PMMA, understanding the consequences of E-beam sterilization on the intrinsic properties of PMMA is vital for clinical implementation. A detailed assessment of the chemical, optical, mechanical, morphological, and biological properties of medical-grade PMMA after E-beam sterilization at 25 and 50 kiloGray (kGy) is reported. Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry studies indicate that E-beam irradiation has minimal effect on the chemical properties of the PMMA at these doses. While 25 kGy irradiation does not alter the mechanical and optical properties of the PMMA, 50 kGy reduces the flexural strength and transparency by 10% and 2%, respectively. Atomic force microscopy demonstrates that E-beam irradiation reduces the surface roughness of PMMA in a dose dependent manner. Live-Dead, AlamarBlue, immunocytochemistry, and complement activation studies show that E-beam irradiation up to 50 kGy has no adverse effect on the biocompatibility of the PMMA. These findings suggest that E-beam irradiation at 25 kGy may be a safe and efficient alternative for PMMA sterilization.

Graphene-Lined Porous Gelatin Glycidyl Methacrylate Hydrogels: Implications for Tissue Engineering.

Despite rigorous research, inferior mechanical properties and structural homogeneity are the main challenges constraining hydrogel's suturability to host tissue and limiting its clinical applications. To tackle those, we developed a reverse solvent interface trapping method, in which organized, graphene-coated microspherical cavities were introduced into a hydrogel to create heterogeneity and make it suturable. To generate those cavities, (i) graphite exfoliates to graphene sheets, which spread at the water/ heptane interfaces of the microemulsion, (ii) heptane fills the microspheres coated by graphene, and (iii) a cross-linkable hydrogel dissolved in water fills the voids. Cross-linking solidifies such microemulsion to a strong, suturable, permanent hybrid architecture, which has better mechanical properties, yet it is biocompatible and supports cell adhesion and proliferation. These properties along with the ease and biosafety of fabrication suggest the potential of this strategy to enhance tissue engineering outcomes by generating various suturable scaffolds for biomedical applications, such as donor cornea carriers for Boston keratoprosthesis (BK).

Golgi α1,2-mannosidase I induces clustering and compartmentalization of CD147 during epithelial cell migration.

CD147 is a widely expressed matrix metalloproteinase inducer involved in the regulation of cell migration. The high glycosylation and ability to undergo oligomerization have been linked to CD147 function, yet there is limited understanding on the molecular mechanisms behind these processes. The current study demonstrates that the expression of Golgi α1,2-mannosidase I is key to maintaining the cell surface organization of CD147 during cell migration. Using an in vitro model of stratified human corneal epithelial wound healing, we show that CD147 is clustered within lateral plasma membranes at the leading edge of adjacent migrating cells. This localization correlates with a surge in matrix metalloproteinase activity and an increase in the expression of α1,2-mannosidase subtype IC (MAN1C1). Global inhibition of α1,2-mannosidase I activity with deoxymannojirimycin markedly attenuates the glycosylation of CD147 and disrupts its surface distribution at the leading edge, concomitantly reducing the expression of matrix metalloproteinase-9. Likewise, treatment with deoxymannojirimycin or siRNA-mediated knockdown of MAN1C1 impairs the ability of the carbohydrate-binding protein galectin-3 to stimulate CD147 clustering in unwounded cells. We conclude that the mannose-trimming activity of α1,2-mannosidase I coordinates the clustering and compartmentalization of CD147 that follows an epithelial injury.

In vitro susceptibility of microorganisms isolated from cold stored corneas: increased gentamicin-resistance in cornea banking.

Donor cornea contamination is one of the major risks for corneal transplants. The use of antibiotics in storage media remains as one of the most important security measurements to minimize the contamination risk in corneal preservation. Since antibiotic resistance among microorganisms have been rising gradually, it is important to gain knowledge about the antimicrobial susceptibility pattern for choosing the most suitable antimicrobial agents. Thus, we evaluated the in vitro susceptibility of microorganisms isolated in donor corneas processed at the Center for Blood Transfusion, Tissues and Cells (Córdoba, Spain) during 4 years in order to evaluate the efficiency, and to promote changes for further antibiotics use. Our results show the high rate of resistance to gentamicin, an antibiotic used in corneal preservation media such as Optisol GS and Eusol-C. Conversely, all the analyzed microorganisms were sensitive to vancomycin. This suggests the possibility of replacing gentamicin with another more effective antibacterial agent such as vancomycin.

Successful development and clinical translation of a novel anterior lamellar artificial cornea.

Blindness due to corneal diseases is a common pathology affecting up to 23 million individuals worldwide. The tissue-engineered anterior human cornea, which is currently being tested in a Phase I/II clinical trial to treat severe corneal trophic ulcers with preliminary good feasibility and safety results. This bioartificial cornea is based on a nanostructured fibrin-agarose biomaterial containing human allogeneic stromal keratocytes and cornea epithelial cells, mimicking the human native anterior cornea in terms of optical, mechanical, and biological behavior. This product is manufactured as a clinical-grade tissue engineering product, fulfilling European requirements and regulations. The clinical translation process included several phases: an initial in vitro and in vivo preclinical research plan, including preclinical advice from the Spanish Medicines Agency followed by additional preclinical development, the adaptation of the biofabrication protocols to a good manufacturing practice manufacturing process, including all quality controls required, and the design of an advanced therapy clinical trial. The experimental development and successful translation of advanced therapy medicinal products for clinical application has to overcome many obstacles, especially when undertaken by academia or SMEs. We expect that our experience and research strategy may help future researchers to efficiently transfer their preclinical results into the clinical settings.