Naoki Okumura

Doshisha University · Department of Biomedical Engneering

The transplantation of cultivated corneal endothelial cells (CECs) has gained attention recently for the treatment of patients with corneal endothelial dysfunction. However, an efficient culturing technique for human (H)CECs has yet to be properly established. The present study was conducted to investigate the applicability of the Rho kinase (ROCK)...

Corneal endothelial dysfunction accompanied by visual disturbance is a primary indication for corneal transplantation. We previously reported that the adhesion of corneal endothelial cells (CECs) to a substrate was enhanced by the selective ROCK inhibitor Y-27632. It is hypothesized that the inhibition of ROCK signaling may manipulate cell adhesion...

Background: Corneal endothelial cell (CEC) disorders, such as Fuchs's endothelial corneal dystrophy, induce abnormal corneal hydration and result in corneal haziness and vision loss known as bullous keratopathy. We investigated whether injection of cultured human CECs supplemented with a rho-associated protein kinase (ROCK) inhibitor into the ante...

Purpose: CTG trinucleotide repeat (TNR) expansion is frequently found in transcription factor 4 (TCF4) in Fuchs' endothelial corneal dystrophy (FECD), though the effect of TNR expansion on FECD pathophysiology remains unclear. The purpose of this study was to evaluate the effect of TNR expansion on TCF4 expression in corneal endothelium of patient...

Purpose: To investigate single nucleotide polymorphisms (SNPs) and trinucleotide repeat (TNR) expansion in the transcription factor 4 (TCF4) gene in a large cohort of German patients with Fuchs endothelial corneal dystrophy (FECD). Methods: Genomic DNA was obtained from 398 patients with FECD and from 58 non-FECD controls. Thirty-seven previousl...

To evaluate the pharmacokinetics of ganciclovir eye drops by comparing solutions prepared from ganciclovir for intravenous infusion and ganciclovir gel and to assess the impact of systemic administration on drug levels in ocular tissues and serum. Experimental study design. Ganciclovir solutions (0.5% and 1.0%) prepared by diluting DENOSINE ® IV In...

Purpose To determine whether the clinical and paraclinical course of Fuchs endothelial corneal dystrophy (FECD) over 1 year is related to the extent of triplet repetition in the transcription factor 4 (TCF4) gene. Methods A prospective study with a 1-year follow-up was conducted. A total of 104 patients (160 eyes) with FECD and an equivalent numbe...

Purpose This study evaluated the dysregulation of TCF4 isoforms and differential exon usage (DEU) in corneal endothelial cells (CECs) of Fuchs endothelial corneal dystrophy (FECD) with or without trinucleotide repeat (TNR) expansion in the intron region of the TCF4 gene. Methods Three RNA-Seq datasets of CECs (our own and two other previously publ...

Purpose : The recognition of subclinical edema in Fuchs Endothelial Corneal Dystrophy (FECD) has important clinical implications: objective treatment-oriented stratification of disease, tracking progression & prognostication. While tomographic features have been identified to define subclinical edema, their morphological & visual correlates have no...

Corneal endothelial decompensation is treated by the corneal transplantation of donor corneas, but donor shortages and other problems associated with corneal transplantation have prompted investigations into tissue engineering therapies. For clinical use, cells used in tissue engineering must undergo strict quality control to ensure their safety an...

Purpose: There are no defined diagnostic criteria and severity classification for Fuchs endothelial corneal dystrophy (FECD), which are required for objective standardized assessments. Therefore, we performed a systematic literature review of the current diagnosis and severity classification of FECD. Methods: We searched the Ovid MEDLINE and Web...

Multiple research groups now theorize that tissue engineering will provide novel therapies for treating corneal endothelial cell (CEC) decompensation. In 2013, we initiated first-in-man clinical research (not an Investigational New Drug [IND] clinical trial) of a CEC injection therapy at the Kyoto Prefectural University of Medicine in Japan. In a c...

Fuchs endothelial corneal dystrophy (FECD) is a slowly evolving, bilateral disease of the corneal endothelium, characterized by an abnormal accumulation of extracellular matrix (ECM) in the basement membrane (Descemet’s membrane, DM). This results in the formation of small round excrescences, called guttae, and a progressive disappearance of endoth...

Fuchs endothelial corneal dystrophy (FECD) is the most common inherited corneal disease. Fibrillar focal excrescences called guttae and corneal edema due to corneal endothelial cell death result in progressive vision loss. Multiple genetic variants have been reported, but the pathogenesis of FECD is not fully understood. In this study, we used RNA-...

The contact specular microscope has a wider angle of view than that of the non-contact specular microscope but still cannot capture an image of the entire cornea. To obtain such an image, it is necessary to prepare film on the parts of the image captured sequentially and combine them to create a complete image. This study proposes a framework to au...

Purpose: Fuchs Endothelial Corneal Dystrophy (FECD) is characterized by the progressive slow accumulation of extra cellular matrix (ECM) forming Descemetic excrescents named guttae and by an increase in the thickness of the Descemet membrane (DM). Nevertheless, FECD pathophysiology remains only partially understood. Aim: To present the expression o...

Purpose: To compare the capacity of anterior segment optical coherence tomography (AS-OCT) and Scheimpflug camera in detecting subclinical corneal edema in patients with Fuchs endothelial corneal dystrophy (FECD). Methods: 177 eyes of 103 patients with FECD without obvious corneal edema were included and analysed in this single-center prospective s...

Fuchs endothelial corneal dystrophy (FECD) is the most common inherited corneal disease. Fibrillar focal excrescences called guttae and corneal edema due to corneal endothelial cell death result in progressive vision loss. Multiple genetic variants have been reported, but the pathogenesis of FECD is not fully understood. In this study, we used RNA-...

Visible light, particularly in the blue region of the spectrum, can cause cell dysfunction through the generation of singlet oxygen, contributing to cellular aging and age-related pathologies. Although photooxidation of nucleic acids, lipids, and amino acids has been extensively studied, the magnitude and span of blue-light-induced protein damages...

Purpose To report a detailed surgical procedure of tissue engineered endothelial keratoplasty (TEEK) in a rabbit model and its postoperative evaluation. Methods TEEKs were prepared 7 days before transplantation by seeding human or rabbit corneal endothelial cells on either femtosecond laser-cut ultrathin human stromal lamellae (fs-UTSL) or femtose...

Purpose: The purpose of this study was to assess the U-Net-based convolutional neural network performance for segmenting corneal endothelium and guttae of Fuchs endothelial corneal dystrophy. Methods: Twenty-eight images of corneal endothelial cells and guttae of Col8a2L450W/L450W knock-in mice were obtained by specular microscopy. We used 20 im...

In 2013, a clinical trial was initiated to investigate cell therapy for the treatment of corneal endothelial decompensation. Cultivating human corneal endothelial cells (CECs) while maintaining their functional phenotype is challenging; therefore, establishment of a confirmed protocol is pivotal for obtaining approval from regulatory authorities fo...

PURPOSE To investigate the safety and efficacy of cultured human corneal endothelial cell (hCEC)-injection therapy with mature differentiated (mature) cell subpopulations (SPs) for corneal endothelial failure (CEF). DESIGN Comparative, interventional case series. METHODS This study involved 18 eyes with CEF that underwent cultured hCEC-injection...

This work presents a numerical scheme based on operator splitting for the thermo-fluid-dynamical simulation of aqueous humor flow in the anterior chamber of the human eye. The stability properties of the scheme are investigated theoretically. Numerical results are presented for different postures and different external temperatures.

Purpose: The purpose of this article was to study the clinical, optical, and morphological correlates of visual function in patients with Fuchs endothelial corneal dystrophy (FECD). Methods: The case records were analyzed for patients diagnosed with FECD between September 2019 and March 2020. The best-corrected visual acuity (BCVA) was recorded...

Purpose : Patients with Fuchs endothelial corneal dystrophy (FECD) often harbor expansion of a trinucleotide CTG repeat in the TCF4 gene, thus suggesting that TCF4 is a potential causative gene for FECD. We previously reported that the expression of TCF4 is upregulated in the corneal endothelium of FECD patients. The purpose of this present study w...

Purpose: The aim of this study was to investigate the immune cells on corneal endothelium of the graft in patients who underwent penetrating keratoplasty (PK), Descemet-stripping endothelial keratoplasty (DSEK), and Descemet membrane endothelial keratoplasty (DMEK). Methods: A total of 43 eyes of 43 patients who underwent PK (17 eyes), DSEK (13...

Purpose: To report evidences that the abnormal endothelium of some Fuchs endothelial corneal dystrophy (FECD) present centripetal radial lines over 360 degrees. Methods: A case report of retroilluminated pictures of 2 patients with FECD and flat mounts of isolated Descemet membranes of 1 patient with FECD and of 1 healthy donor. Interpretation a...

Purpose TGF‐βs trigger ENdothelial‐Mesenchymal Transition (EnMT) in corneal endothelial cells (ECs) in animal models of endothelial wound healing. All the 3 isoforms of TGF‐β were detected in human aqueous humor and their receptors were detected in ECs. More and more evidence indicated that central and peripheral ECs have a different status. Aim T...

Purpose Rho-associated kinase (ROCK) inhibitors have been successfully used as a rescue strategy in eyes that failed to clear after descemetorhexis without endothelial graft for treatment of Fuchs endothelial corneal dystrophy (FECD). The functional mechanisms by which ROCK inhibitors modulate corneal endothelial cell regeneration in FECD patients...

The corneal endothelium maintains corneal transparency; consequently, damage to this endothelium by a number of pathological conditions results in severe vision loss. Publicly available expression databases of human tissues are useful for investigating the pathogenesis of diseases and for developing new therapeutic modalities; however, databases fo...

Purpose: To report the safety and efficacy of a novel cell-injection therapy using cultured human corneal endothelial cells (hCECs) for endothelial failure conditions via the report of the long-term clinical data of 5-years postoperative in a 'first-in-man' clinical trial group. Design: Prospective observational study. Participants: This study...

Introduction Tissue engineering therapy for the treatment of corneal endothelial decompensation was proposed in the 1970s. In 2013, a clinical trial of the injection of cultured human corneal endothelial cells into the anterior chamber of patients with corneal endothelial decompensation was started in Japan. Areas covered The aim of this paper is...

Penetrating keratoplasty was the only therapeutic choice for the treatment of corneal endothelial decompensation until the introduction of evolutional endothelial keratoplasties, namely Descemet’s stripping automated endothelial keratoplasty (DSAEK) and Descemet’s membrane endothelial keratoplasty (DMEK). Although now in widespread use, DSAEK and D...

Purpose: To evaluate the association of single nucleotide polymorphisms (SNPs) and the intronic expansion of a trinucleotide repeat (TNR) in the TCF4 gene with Fuchs endothelial corneal dystrophy (FECD) in a Thai population. Methods: In total, 54 Thai FECD patients and 54 controls were recruited for the study. Five SNPs (rs613872, rs2123392, rs1...

Transparency of the cornea is essential for vision and is maintained by the corneal endothelium. Consequently, corneal endothelial decompensation arising from irreversible damage to the corneal endothelium causes severe vision impairment. Until recently, transplantation of donor corneas was the only therapeutic choice for treatment of endothelial d...

Purpose Hospital-prepared topical ganciclovir eye drops made from intravenous infusions are used to treat cytomegalovirus corneal endotheliitis. This study assessed the efficacy of these eye drops. Study design Experimental study design. Methods Ganciclovir solutions (0.5% and 1.0%) prepared by diluting DENOSINE® IV Infusion in saline were stored...

Cell based therapy, as an alternative to conventional donor corneal transplantation, is anticipated to provide a less invasive and more effective therapeutic modality for corneal endothelial dysfunction. The proliferative capability of human corneal endothelial cells is severely controlled, thus making the establishment of optimal conditions for th...

Purpose: To develop software to evaluate the fibroblastic morphological changes in cultured human corneal endothelial cells (HCECs) as a quality control measure for use in tissue engineering therapy. Methods: Software was designed to recognize cell borders, to approximate cell shape as an ellipse, and to calculate the aspect ratio of the ellipse...

Purpose: We have performed clinical research on cell-based therapy for corneal endothelial decompensation since 2013. The purpose of this study was to investigate the usefulness of a p38 MAPK inhibitor for promoting proliferation of human corneal endothelial cells (HCECs). Methods: HCECs were cultured in media supplemented with various low-molec...

Background Fuchs Endothelial Corneal Dystrophy (FECD) is a progressive disease that affects the corneal endothelium in both eyes. Recent studies have identified a novel genetic basis for FECD, and basic research findings have provided evidence for its underlying pathophysiology. Since its first description by Ernst Fuchs in 1910, the only therapeut...

Purpose: The aim of this study was to investigate the existence of presumed immune cells observed by contact specular microscopy in patients who underwent penetrating keratoplasty (PK) and Descemet stripping automated endothelial keratoplasty (DSAEK). Methods: This cross-sectional study was conducted on consecutive patients who underwent follow-...

Purpose: To assess corneal endothelial cell loss after penetrating keratoplasty (PK) treatment for laser iridotomy (LI)-induced bullous keratopathy (BK). Methods: A retrospective study conducted on consecutive patients who underwent PK between March 2000 and December 2011. Patients who had undergone more than 24 months of follow-up were included...

Purpose: To evaluate the effect of corneal vesicles in patients with posterior corneal vesicles (PCV) on corneal endothelial cell (CEC) density and the acquisition of amblyopia. Methods: In this retrospective study of patients with PCV (18 eyes of 14 patients), CEC density was examined by noncontact specular microscopy during each follow-up exam...

Purpose: This study investigates the possible role of the filtration bleb in the continuous decrease in corneal endothelial cell (CEC) density observed following trabeculectomy. Methods: This study involved 51 eyes of 37 glaucoma patients who underwent trabeculectomy. The CEC density was determined by contact specular microscopy in three areas:...

Purpose: The cell-cell adhesion molecules, cadherins and nectins, are involved in the formation of adherens junctions. However, involvement of nectins in the corneal endothelium has not yet been established. This study investigated the involvement of nectins in adherens junctions of the corneal endothelium. Methods: Nectin and cadherin expressio...

Corneal transparency is maintained by the corneal endothelium through its pump and barrier function. Severe corneal endothelial damage results in dysregulation of water flow and eventually causes corneal haziness and deterioration of visual function. In 2013, we initiated clinical research of cell-based therapy for treating corneal decompensation....

Data set of Fig 5B–5E. (XLSX)

Fuchs endothelial corneal dystrophy (FECD) is a slowly progressive bilateral disease of corneal endothelium in which accumulation of extracellular matrix (ECM) and loss of corneal endothelial cells (CECs) are phenotypic features. The corneal endothelium maintains corneal transparency by regulating water hydration; consequently, corneal endothelial...

Aim To investigate the viability of donor corneal endothelial cells (CECs) preserved in storage media by histological examination. Methods Twenty-eight donor corneas were obtained from SightLife Eye Bank (Seattle, Washington), and redundant peripheral portions of those corneas were used for histological examination after removal of the centre corn...

Purpose: To develop analysis software for cultured human corneal endothelial cells (HCECs). Methods: Software was designed to recognize cell borders and to provide parameters such as cell density, coefficient of variation, and polygonality of cultured HCECs based on phase contrast images. Cultured HCECs with high or low cell density were incubat...

Purpose The purpose of this study was to investigate the feasibility of poly lactic/glycolic acid (PLGA) as a drug delivery carrier of Rho kinase (ROCK) inhibitor for the treatment of corneal endothelial disease. Method ROCK inhibitor Y-27632 and PLGA were dissolved in water with or without gelatin (W1), and a double emulsion [(W1/O)/W2] was forme...

Purpose: The unfolded protein response (UPR) is believed to play a role in the pathogenesis of Fuchs' endothelial corneal dystrophy (FECD). The purpose of this study was to investigate whether unfolded proteins accumulate in the corneal endothelium in FECD and if they are involved in triggering cell death. Methods: Descemet's membranes with corn...

Optimization of culture conditions for human limbal epithelial stem/progenitor cells (LEPC) that incorporate the in vivo cell-matrix interactions are essential to enhance LEPC ex vivo-expansion and transplantation efficiency. Here, we investigate the efficacy of laminin (LN) isoforms preferentially expressed in the limbal niche as culture matrices...

Purpose: We have begun a clinical trial of a cell-based therapy for corneal endothelial dysfunction in Japan. The purpose of this study was to investigate the usefulness of a p38 MAPK inhibitor for prevention cellular senescence in cultivated human corneal endothelial cells (HCECs). Methods: HCECs of 10 donor corneas were divided and cultured wi...

ROCK (Rho kinase) signaling regulates a wide spectrum of fundamental cellular events and is involved in a variety of pathological conditions. It has therefore attracted research interest as a potential therapeutic target for combating various diseases. We showed that inhibition of ROCK enhances cell proliferation, promotes cell adhesion onto a subs...

Purpose: The aim of this study was to evaluate which amino acid(s) among the 20 standard protein amino acids is indispensable for the survival of cultured human corneal endothelial cells (HCECs). Methods: HCECs were cultured in amino acid screening media that were missing 1 specific amino acid, and cell growth was evaluated. After this first sel...

Purpose To examine the effects of transcorneal freezing using a new cryoprobe designed for corneal endothelial surgery. Methods A freezing console employing nitrous oxide as a cryogen was used to cool a series of different cryoprobe tip designs made of silver for high thermal conductivity. In vitro studies were conducted on 426 porcine corneas, fo...

Purpose: Corneal endothelial cell density undergoes a progressive decrease for many years after transplantation, eventually threatening patients with late endothelial failure. The purpose of this study was to investigate the possibility of an immunologic response in successfully grafted corneal endothelium. Methods: The corneal endothelium of pa...

SUPPLEMENTAL TABLE 1. Grading system for corneal opacification and conjunctival hyperemia modified from Sotozono et al. [17].

Purpose: Rho kinase (ROCK) pathways control fundamental cell functions, making ROCK an important therapeutic target in several pathophysiologic conditions. The purpose of this study was to investigate whether inhibition of ROCK can suppress apoptosis of the corneal endothelium and to determine the role of ROCK signaling in regulating apoptosis. M...

Background: The cornea is transparent tissue that serves as the window of the eye, allowing light to enter from the outer environment. The corneal endothelium maintains corneal transparency; thus, its dysfunction results in corneal haziness and causes severe vision loss. The only available therapeutic choice for treating corneal endothelial dysfun...

Purpose: The aim of this study was to evaluate the effect of trabeculotomy (TLO) on glaucoma and endothelial cell loss after penetrating keratoplasty (PK). Methods: A retrospective study was conducted on consecutive patients who underwent PK and in whom more than 24 months of follow-up was available. Patients were categorized into the PK+TLO gro...

Purpose To observe the most peripheral region of the corneal endothelial cell (CEC) layer as long as optically recordable by use of a prototype slit-scanning wide-field contact specular microscope and produce a panoramic image to evaluate the variation of CEC density with ageing. Design Observational case series study. Methods This study involved...

The corneal endothelium maintains corneal transparency by its pump and barrier functions; consequently, its decompensation due to any pathological reason causes severe vision loss due to corneal haziness. Corneal transplantation is the only therapeutic choice for treating corneal endothelial dysfunction, but associated problems, such as a shortages...

Composition table of cell therapy vehicle (CTV). This supporting table provides composition of CTV. (PDF)

Participant-level data. This supporting information file provides participant-level data. (XLSX)

The corneal endothelium maintains corneal transparency; consequently, its dysfunction causes severe vision loss. Tissue engineering-based therapy, as an alternative to conventional donor corneal transplantation, is anticipated to provide a less invasive and more effective therapeutic modality. We conducted a preclinical study for cell-based therapy...

Purpose: Ripasudil (Glanatec), a selective rho-associated coiled coil-containing protein kinase (ROCK) inhibitor, was approved as a glaucoma and ocular hypertension treatment in Japan in 2014. The purpose of this study was to investigate the feasibility of using ripasudil eye drops to treat corneal endothelial injuries. Methods: Cultured human c...

Purpose: Ripasudil (Glanatec), a selective Rho-associated coiled coil-containing protein kinase (ROCK) inhibitor, was approved in Japan in September 2014 for the treatment of glaucoma and ocular hypertension. The purpose of this study was to investigate the effect of ripasudil eye drops on corneal endothelial morphology, as ROCK signaling is known...