Transplantation of human umbilical mesenchymal stem cells cures the corneal defects of mucopolysaccharidosis VII mice

The Potential of Mesenchymal Stromal Cell as Therapy in Neonatal Diseases

Mesenchymal stromal cells (MSCs) can be derived from various tissue sources, such as the bone marrow (BMSCs), adipose tissue (ADSCs), umbilical cord (UC-MSCs) and umbilical cord blood (UCB-MSCs). Clinical trials have been conducted to investigate the potential of MSCs in ameliorating neonatal diseases, including bronchopulmonary dysplasia (BPD), intraventricular hemorrhage (IVH) and necrotizing enterocolitis (NEC). In preclinical studies, MSC therapy has been tested for the treatment of various neonatal diseases affecting the heart, eye, gut, and brain as well as sepsis. Up to date, the number of clinical trials using MSCs to treat neonatal diseases is still limited. The data reported thus far positioned MSC therapy as safe with positive outcomes. However, most of these trials are still preliminary and generally smaller in scale. Larger trials with more appropriate controls and a longer follow-up period need to be conducted to prove the safety and efficacy of the therapy more conclusively. This review discusses the current application of MSCs in treating neonatal diseases, its mechanism of action and future direction of this novel therapy, including the potential of using MSC-derived extracellular vesicles instead of the cells to treat various clinical conditions in the newborn.

MSCs helped reduce scarring in the cornea after fungal infection when combined with anti-fungal treatment

Background

Fungal Keratitis (FK) is an infective keratopathy with extremely high blindness rate. The damaging effect of this disease is not only the destruction of corneal tissue during fungal infection, but also the cornea scar formed during the healing period after infection control, which can also seriously affect a patient’s vision. The purpose of the study was to observe the effect of umbilical cord mesenchymal stem cells (uMSCs) on corneal scar formation in FK.

Methods

The FK mouse model was made according to a previously reported method. Natamycin eye drops were used for antifungal treatment 24 h after modeling. There are four groups involved in the study, including control group, FK group, vehicle^inj FK group and uMSCs^inj FK group. Mice in uMSCs^inj FK group received repeated subconjunctival injections of uMSCs for 3 times at the 1d, 4d and 7d after FK modeling. At 14d, 21d and 28d after trauma, clinical observation, histological examination, second harmonic generation and molecular assays were performed.

Results

The uMSCs topical administration reduced corneal scar formation area and corneal opacity, accompanying with decreased corneal thickness and inflammatory cell infiltration, following down-regulated fibrotic-related factors α-SMA, TGFβ1, CTGF, and COLI and finally inhibited phosphorylation of TGFβ1/Smad2 signaling pathway during FK corneal fibrosis.

Conclusion

The results confirmed that uMSCs can improve corneal opacity during the scar formation stage of FK, and exert anti-inflammatory and anti-fibrotic effects.

Corneal Stromal Regeneration: Current Status and Future Therapeutic Potential

The corneal stroma comprises 90% of the corneal thickness and is critical for the cornea's transparency and refractive function necessary for vision. When the corneal stroma is altered by disease, injury, or scarring, however, an irreversible loss of transparency can occur. Corneal stromal pathology is the cause of millions of cases of blindness globally, and although corneal transplantation is the standard therapy, a severe global deficit of donor corneal tissue and eye banking infrastructure exists, and is unable to meet the overwhelming need. An alternative approach is to harness the endogenous regenerative ability of the corneal stroma, which exhibits self-renewal of the collagenous extracellular matrix under appropriate conditions. To mimic endogenous stromal regeneration, however, is a challenge. Unlike the corneal epithelium and endothelium, the corneal stroma is an exquisitely organized extracellular matrix containing stromal cells, proteoglycans and corneal nerves that is difficult to recapitulate in vitro. Nevertheless, much progress has recently been made in developing stromal equivalents, and in this review the most recent approaches to stromal regeneration therapy are described and discussed. Novel approaches for stromal regeneration include human or animal corneal and/or non-corneal tissue that is acellular or is decellularized and/or re-cellularized, acellular bioengineered stromal scaffolds, tissue adhesives, 3D bioprinting and stromal stem cell therapy. This review highlights the techniques and advances that have achieved first clinical use or are close to translation for eventual therapeutic application in repairing and regenerating the corneal stroma, while the potential of these novel therapies for achieving effective stromal regeneration is discussed.

Ophthalmological Findings in Mucopolysaccharidoses

The mucopolysaccharidoses (MPS) are a heterogenous group of lysosomal storage disorders caused by the accumulation of glycosaminoglycans (GAGs). The accrual of these compounds results in phenotypically varied syndromes that produce multi-organ impairment with widespread systemic effects. The low incidence of MPS (approximately 1/25,000 live births) in conjunction with the high childhood mortality rate had limited the availability of research into certain clinical features, especially ocular manifestations. As the recent successes of hematopoietic stem cell transplantation (HSCT) and enzyme replacement therapy (ERT) have greatly increased life expectancy in these patients, they have served as a focal point for the transition of research towards improvement of quality of life. Ophthalmological findings in MPS include corneal clouding, glaucoma, optic neuropathies, and retinopathies. While corneal clouding is the most common ocular feature of MPS (especially type I, IVA, and VI), its response to HSCT and ERT is minimal. This review discusses known eye issues in the MPS subtypes, diagnosis of these ocular diseases, current clinical and surgical management, noteworthy research progress, and ultimately presents a direction for future studies.

Therapeutic efficacy of mesenchymal stem cells for the treatment of congenital and acquired corneal opacity

Purpose

Maintenance of a transparent corneal stroma is imperative for proper vision. The corneal stroma is composed of primarily collagen fibrils, small leucine-rich proteoglycans (SLRPs), as well as sparsely distributed cells called keratocytes. The lattice arrangement and spacing of the collagen fibrils that allows for transparency may be disrupted due to genetic mutations and injuries. The purpose of this study is to examine the therapeutic efficacy of human umbilical cord mesenchymal stem/stromal cells (UMSCs) in treating congenital and acquired corneal opacity associated with the loss of collagen V.

Methods

Experimental mice, i.e., wild-type, Col5a1^f/f and Kera-Cre/Col5a1^f/f (Col5a1^∆st/∆st , collagen V null in the corneal stroma) mice in a C57BL/6J genetic background, were subjected to a lamellar keratectomy, and treated with or without UMSC (10⁴ cells/cornea) transplantation via an intrastromal injection or a fibrin plug. In vivo Heidelberg retinal tomograph (HRT II) confocal microscopy, second harmonic generated (SHG) confocal microscopy, histology, and immunofluorescence microscopy were used to assess the corneal transparency of the regenerated corneas.

Results

Col5a1^∆st/∆st mice display a cloudy cornea phenotype that is ameliorated following intrastromal transplantation of UMSCs. Loss of collagen V in Col5a1^∆st/∆st corneas augments the formation of cornea scarring following the keratectomy. UMSC transplantation with a fibrin plug improves the healing of injured corneas and regeneration of transparent corneas, as determined with in vivo HRT II confocal microscopy. Second harmonic confocal microscopy revealed the improved collagen fibril lamellar architecture in the UMSC-transplanted cornea in comparison to the control keratectomized corneas.

Conclusions

UMSC transplantation was successful in recovering some corneal transparency in injured corneas of wild-type, Col5a1^f/f and Col5a1^∆st/∆st mice. The production of collagen V by transplanted UMSCs may account for the regeneration of corneal transparency, as exemplified by better collagen fiber organization, as revealed with SHG signals.

Therapeutic Potential of Mesenchymal Stem Cell-Derived Exosomes in the Treatment of Eye Diseases

Mesenchymal stem cells (MSCs) were, due to their immunomodulatory and pro-angiogenic characteristics, extensively explored as new therapeutic agents in cell-based therapy of uveitis, glaucoma, retinal and ocular surface diseases.Since it was recently revealed that exosomes play an important role in biological functions of MSCs, herewith we summarized current knowledge about the morphology, structure, phenotype and functional characteristics of MSC-derived exosomes emphasizing their therapeutic potential in the treatment of eye diseases.MSC-derived exosomes were as efficient as transplanted MSCs in limiting the extent of eye injury and inflammation. Immediately after intravitreal injection, MSC-derived exosomes, due to nano-dimension, diffused rapidly throughout the retina and significantly attenuated retinal damage and inflammation. MSC-derived exosomes successfully delivered trophic and immunomodulatory factors to the inner retina and efficiently promoted survival and neuritogenesis of injured retinal ganglion cells. MSC-derived exosomes efficiently suppressed migration of inflammatory cells, attenuated detrimental Th1 and Th17 cell-driven immune response and ameliorated experimental autoimmune uveitis. MSC-derived exosomes were able to fuse with the lysosomes within corneal cells, enabling delivering of MSC-derived active β-glucuronidase and consequent catabolism of accumulated glycosaminoglycans, indicating their therapeutic potential in the treatment of Mucopolysaccharidosis VII (Sly Syndrome). Importantly, beneficent effects were noticed only in animals that received MSC-derived exosomes and were not seen after therapy with fibroblasts-derived exosomes confirming specific therapeutic potential of MSCs and their products in the treatment of eye diseases.In conclusion, MSC-derived exosomes represent potentially new therapeutic agents in the therapy of degenerative and inflammatory ocular diseases.

Insight into the Role of Extracellular Vesicles in Lysosomal Storage Disorders

Extracellular vesicles (EVs) have received increasing attention over the last two decades. Initially, they were considered as just a garbage disposal tool; however, it has progressively become clear that their protein, nucleic acid (namely miRNA and mRNA), and lipid contents have signaling functions. Besides, it has been established that cells release different types of vesicular structures for which characterization is still in its infancy. Many stress conditions, such as hypoxia, senescence, and oncogene activation have been associated with the release of higher levels of EVs. Further, evidence has shown that autophagic–lysosomal pathway abnormalities also affect EV release. In fact, in neurodegenerative diseases characterized by the accumulation of toxic proteins, although it has not become clear to what extent the intracellular storage of undigested materials itself has beneficial/adverse effects, these proteins have also been shown to be released extracellularly via EVs. Lysosomal storage disorders (LSDs) are characterized by accumulation of undigested substrates within the endosomal–lysosomal system, due either to genetic mutations in lysosomal proteins or to treatment with pharmacological agents. Here, we review studies investigating the role of lysosomal and autophagic dysfunction on the release of EVs, with a focus on studies exploring the release of EVs in LSD models of both genetic and pharmacological origin. A better knowledge of EV-releasing pathways activated in lysosomal stress conditions will provide information on the role of EVs in both alleviating intracellular storage of undigested materials and spreading the pathology to the neighboring tissue.

Regenerative Surgery of the Corneal Stroma for Advanced Keratoconus: 1-Year Outcomes

PURPOSE

This study evaluated 1-year safety and efficacy outcomes of corneal stroma cell therapy. Therapy consisted of implanting autologous adipose-derived adult stem cells (ADASc) with or without sheets of decellularized donor human corneal stroma within the stroma of patients with advanced keratoconus.

DESIGN

This was a prospective interventional non-randomized series of cases.

METHODS

Fourteen consecutive patients were selected and divided into 3 experimental groups. Group A patients underwent implantation of autologous ADASc alone (3 × 10⁶ cells/1 mL) (n = 5). Group B patients received decellularized donor 120-μm-thick corneal stroma lamina alone (n = 5). Group C patients had implantation of recellularized donor lamina with 1 × 10⁶ autologous ADASc plus another 1 × 10⁶ cells/1 mL at the time of the surgery (n = 4). Autologous ADASc were obtained by elective liposuction. Implantation was performed in the corneal stroma through a femtosecond-assisted 9.5-mm diameter lamellar dissection with the patient under topical anesthesia. Twelve months of follow-up data are presented.

RESULTS

No complications were observed during the 1-year follow-up, and full corneal transparency was recovered within 3 months in all patients. No patient lost lines of visual acuity. Corrected distance visual acuity improved 0.231, 0.264, and 0.094 Snellen lines in groups 1, 2, and 3, respectively. In group 1, refractive parameters showed an overall stability, whereas in groups 2 and 3, sphere improved 2.35 diopter (D) and 0.625 D, respectively. Anterior keratometry remained stable (group 1) and improved in groups 2 and 3 (mean improvement of 2D). Corneal aberrometry improved significantly. In optical coherence tomography scans, corneal thickness showed a mean improvement of 14.5 μm (group 1) and 116.4 μm (groups 2 and 3) in the central thickness, and new collagen production was observed at the surgical plane (group 1). Confocal biomicroscopy confirmed the host recellularization of the implanted laminas.

CONCLUSIONS

Intrastromal implantation of autologous ADASc and decellularized human corneal stroma did not show complications at 1 year of follow-up and were moderately effective for the treatment of advanced keratoconus. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Current Trends and Future Perspective of Mesenchymal Stem Cells and Exosomes in Corneal Diseases

The corneal functions (transparency, refractivity and mechanical strength) deteriorate in many corneal diseases but can be restored after corneal transplantation (penetrating and lamellar keratoplasties). However, the global shortage of transplantable donor corneas remains significant and patients are subject to life-long risk of immune response and graft rejection. Various studies have shown the differentiation of multipotent mesenchymal stem cells (MSCs) into various corneal cell types. With the unique properties of immunomodulation, anti-angiogenesis and anti-inflammation, they offer the advantages in corneal reconstruction. These effects are widely mediated by MSC differentiation and paracrine signaling via exosomes. Besides the cell-free nature of exosomes in circumventing the problems of cell-fate control and tumorigenesis, the vesicle content can be genetically modified for optimal therapeutic affinity. The pharmacology and toxicology, xeno-free processing with sustained delivery, scale-up production in compliant to Good Manufacturing Practice regulations, and cost-effectiveness are the current foci of research. Routes of administration via injection, topical and/or engineered bioscaffolds are also explored for its applicability in treating corneal diseases.

The journey of hyaluronan research in the Journal of Biological Chemistry

Hyaluronan has a very simple structure. It is a linear glycosaminoglycan composed of disaccharide units of GlcNAc and d-glucuronic acid with alternating β-1,4 and β-1,3 glycosidic bonds that can be repeated 20,000 or more times, a molecular mass >8 million Da, and a length >20 μm. However, it has a very complex biology. It is a major, ubiquitous component of extracellular matrices involved in everything from fertilization, development, inflammations, to cancer. This JBC Review highlights some of these processes that were initiated through publications in the Journal of Biological Chemistry.

Molecular Mechanisms Responsible for Therapeutic Potential of Mesenchymal Stem Cell-Derived Secretome

Mesenchymal stem cell (MSC)-sourced secretome, defined as the set of MSC-derived bioactive factors (soluble proteins, nucleic acids, lipids and extracellular vesicles), showed therapeutic effects similar to those observed after transplantation of MSCs. MSC-derived secretome may bypass many side effects of MSC-based therapy, including unwanted differentiation of engrafted MSCs. In contrast to MSCs which had to be expanded in culture to reach optimal cell number for transplantation, MSC-sourced secretome is immediately available for treatment of acute conditions, including fulminant hepatitis, cerebral ischemia and myocardial infarction. Additionally, MSC-derived secretome could be massively produced from commercially available cell lines avoiding invasive cell collection procedure. In this review article we emphasized molecular and cellular mechanisms that were responsible for beneficial effects of MSC-derived secretomes in the treatment of degenerative and inflammatory diseases of hepatobiliary, respiratory, musculoskeletal, gastrointestinal, cardiovascular and nervous system. Results obtained in a large number of studies suggested that administration of MSC-derived secretomes represents a new, cell-free therapeutic approach for attenuation of inflammatory and degenerative diseases. Therapeutic effects of MSC-sourced secretomes relied on their capacity to deliver genetic material, growth and immunomodulatory factors to the target cells enabling activation of anti-apoptotic and pro-survival pathways that resulted in tissue repair and regeneration.

Mesenchymal stromal cells for ocular surface repair

INTRODUCTION

Cornea is a transparent, robust tissue that comprises highly organized cells. Disruption of this specialized tissue can lead to scarring and subsequent blindness, making corneal damage a considerable challenge worldwide. At present, the available medical treatments are unable to address the wide range of corneal diseases. Mesenchymal stem cells (MSCs) have increasingly been investigated for their regenerative effect on ocular surface injury due to their unique ability for growth factor production, anti-inflammatory activity, immunomodulatory capacity and differentiation into multiple cell lineages.

AREAS COVERED

Within this review, we explore the pathogenesis of corneal disorders in response to injury and disease, and the potential for MSCs to modulate this process as a treatment. Through the review of over 25 animal studies, we investigate the common mechanisms of action by which MSCs have their effect and discuss their potential for treating and/or preventing corneal deterioration

EXPERT OPINION

Depending on the environmental cues, MSCs can exert a potent effect on corneal wound healing through reducing opacity and vascularization, whilst promoting re-epithelialization. Whilst their mechanism is multifactorial, it seems clear that the anti-inflammatory/immunomodulatory factors they produce in response to damage are key to their control of cellular milieu and improving healing outcomes.

Fibrosis: Shared Lessons From the Lens and Cornea

Regenerative repair in response to wounding involves cell proliferation and migration. This is followed by the reestablishment of cell structure and organization and a dynamic process of remodeling and restoration of the injured cells' extracellular matrix microenvironment and the integration of the newly synthesized matrix into the surrounding tissue. Fibrosis in the lungs, liver, and heart can lead to loss of life and in the eye to loss of vision. Learning to control fibrosis and restore normal tissue function after injury repair remains a goal of research in this area. Here we use knowledge gained using the lens and the cornea to provide insight into how fibrosis develops and clues to how it can be controlled. The lens and cornea are less complex than other tissues that develop life‐threatening fibrosis, but they are well characterized and research using them as model systems to study fibrosis is leading toward an improved understanding of fibrosis. Here we summarize the current state of the literature and how it is leading to promising new treatments. Anat Rec, 2019. © 2019 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.

Cellular therapy of the corneal stroma: a new type of corneal surgery for keratoconus and corneal dystrophies

Cellular therapy of the corneal stroma, with either ocular or extraocular stem cells, has been gaining a lot of interest over the last decade. Multiple publications from different research groups are showing its potential benefits in relation to its capacity to improve or alleviate corneal scars, improve corneal transparency in metabolic diseases by enhancing the catabolism of the accumulated molecules, generate new organized collagen within the host stroma, and its immunosuppressive and immunomodulatory properties. Autologous extraocular stem cells do not require a healthy contralateral eye and they do not involve any ophthalmic procedures for their isolation. Mesenchymal stem cells have been the most widely assayed and have the best potential to differentiate into functional adult keratocytes in vivo and in vitro. While embryonic stem cells have been partially abandoned due to ethical implications, the discovery of the induced pluripotent stem cells (iPSC) has opened a new and very promising field for future research as they are pluripotent cells with the capacity to theoretically differentiate into any cell type, with the special advantage that they are obtained from adult differentiated cells. Cellular delivery into the corneal stroma has been experimentally assayed in vivo in multiple ways: systemic versus local injections with or without a carrier. Encouraging preliminary human clinical data is already available although still very limited, and further research is necessary in order to consolidate the clinical applications of this novel therapeutic line.

Anti-Inflammatory and Anti-Fibrotic Effects of Human Amniotic Membrane Mesenchymal Stem Cells and Their Potential in Corneal Repair

Acute ocular chemical burns are ophthalmic emergencies requiring immediate diagnosis and treatment as they may lead to permanent impairment of vision. The clinical manifestations of such burns are produced by exacerbated innate immune response via the infiltration of inflammatory cells and activation of stromal fibroblasts. New therapies are emerging that are dedicated to repair mechanisms that improve the ocular surface after damage; for example, transplantation of stem cells (SC) has been successfully reported for this purpose. The pursuit of easily accessible, noninvasive procedures to obtain SC has led researchers to focus on human tissues such as amniotic membrane. Human amniotic mesenchymal SC (hAM-MSC) inhibits proinflammatory and fibrotic processes in different diseases. hAM-MSC expresses low levels of classical MHC-I and they do not express MHC-II, making them suitable for regenerative medicine. The aim of this study was to evaluate the effect of intracameral injection of hAM-MSC on the clinical manifestations, the infiltration of inflammatory cells, and the activation of stromal fibroblasts in a corneal alkali-burn model. We also determined the in vitro effect of hAM-MSC conditioned medium (CM) on α-SMA⁺ human limbal myofibroblast (HLM) frequency and on release of neutrophil extracellular traps (NETs). Our results show that intracameral hAM-MSC injection reduces neovascularization, opacity, stromal inflammatory cell infiltrate, and stromal α-SMA⁺ cells in our model. Moreover, in in vitro assays, CM from hAM-MSC decreased the quantity of α-SMA⁺ HLM and the release of NETs. These results suggest that intracameral hAM-MSC injection induces an anti-inflammatory and anti-fibrotic environment that promotes corneal wound healing. Stem Cells Translational Medicine 2018;7:906-917.

Corneal Endothelial Regeneration Using Mesenchymal Stem Cells Derived from Human Umbilical Cord

Corneal blindness is the third leading cause of blindness in the world, and one of the main etiologies is dysfunction of the corneal endothelium. Current treatment of corneal endothelial disease is allogenic corneal transplantation, which is limited by the global shortage of donor corneas and immunological rejection. The corneal endothelium consists of a monolayer of cells derived from the neural crest and mesoderm. Its main function is to prevent corneal edema by tight junctions formed by zonular occludens-1 (ZO-1) and Na, K-ATPase pump function. The human umbilical cord (UC) is a rich source of mesenchymal stem cells (MSCs). UC-MSCs that have multi-lineage potential may be an accessible allogenic source. After inducing differentiation with medium containing glycogen synthase kinase (GSK) 3-β inhibitor, UC-MSCs formed polygonal corneal endothelial-like cells that functioned as tissue-engineered corneal endothelium (UTECE). Expressions of major corneal endothelial markers were confirmed by reverse transcription-polymerase chain reaction (RT-PCR) and quantitative RT-PCR (qRT-PCR). Western blotting confirmed the expression of Na,K-ATPase and PITX2, the functional and developmental markers of corneal endothelial cells. Immunohistochemistry revealed the localization of Na,K-ATPase and ZO-1 in cell-cell junctions, suggesting the presence of tight junctions. In vitro functional analysis revealed that UTECE had significantly high pump function compared with UC-MSCs. Moreover, UTECE transplanted into a rabbit model of bullous keratopathy successfully maintained corneal thickness and transparency. Our findings suggest that UTECE may be used as a source of allogenic cells for the treatment of corneal endothelial disease.

Cellular Therapy With Human Autologous Adipose-Derived Adult Stem Cells for Advanced Keratoconus

PURPOSE

The aim of this phase 1 study was to preliminarily evaluate the safety and efficacy of autologous adipose-derived adult stem cell (ADASC) implantation within the corneal stroma of patients with advanced keratoconus.

METHODS

Five consecutive patients were selected. Autologous ADASCs were obtained by elective liposuction. ADASCs (3 × 10) contained in 1 mL saline were injected into the corneal stroma through a femtosecond-assisted 9.5-mm diameter lamellar pocket under topical anesthesia. Patients were reviewed at 1 day, 1 week, 1, 3, and 6 months postoperatively. Visual function, manifest refraction, slit-lamp biomicroscopy, intraocular pressure, endothelial cell density, corneal topography, corneal optical coherence tomography, and corneal confocal biomicroscopy were recorded.

RESULTS

No intraoperative or postoperative complications were recorded, with full corneal transparency recovery within 24 hours. Four patients completed the full follow-up. All patients improved their visual function (mean: 1 line of unaided and spectacle-corrected distance vision and 2 lines of rigid contact lens distance vision). Manifest refraction and topographic keratometry remained stable. Corneal optical coherence tomography showed a mean improvement of 16.5 μm in the central corneal thickness, and new collagen production was observed as patchy hyperreflective areas at the level of the stromal pocket. Confocal biomicroscopy confirmed the survival of the implanted stem cells at the surgical plane. Intraocular pressure and endothelial cell density remained stable.

CONCLUSIONS

Cellular therapy of the human corneal stroma in vivo with autologous ADASCs appears to be safe. Stem cells survive in vivo with intrastromal new collagen production. Future studies with larger samples are required to confirm these preliminary results.

Objective quantification of corneal haziness using anterior segment optical coherence tomography

Purpose

To quantify normal corneal transparency by anterior segment optical coherence tomography (AS-OCT) by measuring the average pixel intensity. To analyze the variation in the average pixel intensity in mild and severe grades of corneal opacities.

Methods

This is an observational, cross-sectional study of 38 eyes from 19 patients with mild or severe grades of corneal opacities greater than 3 mm and a normal contralateral cornea. AS-OCT was performed centered on the opacity with a 3 mm cruciate protocol. A similar image is taken of the contralateral clear cornea in the same quadrant. The average pixel intensity was calculated in a standardized manner using MATLAB software.

Result

The average pixel intensity of the normal cornea was 99.6 ± 10.9 [standard deviation (SD)]. The average pixel intensity of the mild and severe corneal opacities was 115.5 ± 9.1 and 141.1 ± 10.3, respectively. The differences were statistically significant.

Conclusions

AS-OCT images can be used to quantify corneal transparency. Average pixel intensity is a measure that varies significantly with varying corneal opacification.

Corneal Stroma Enhancement With Decellularized Stromal Laminas With or Without Stem Cell Recellularization for Advanced Keratoconus

PURPOSE

This phase 1 study seeks to preliminarily evaluate the safety and efficacy of decellularized human corneal stromal lamina transplantation with or without autologous adipose-derived adult stem cell recellularization within the corneal stroma of patients with advanced keratoconus.

DESIGN

Phase 1 clinical trial.

METHODS

Femtosecond-assisted 120-μm thickness and 9-mm diameter laminas were obtained from the anterior stroma of human donor corneas and decellularized with a sodium dodecyl sulfate solution. Autologous adipose-derived adult stem cells were obtained by elective liposuction and cultured onto both sides of the lamina. Five patients received the decellularized lamina alone and 4 patients the recellularized lamina into a femtosecond-assisted 9.5-mm diameter lamellar pocket under topical anesthesia. The total duration of follow-up was 6 months.

RESULTS

No case showed clinical haze or scarring by month 3. Six months after surgery, patients showed a general improvement of all visual parameters, with a mean unaided visual acuity from 0.109 to 0.232 (P = .05) and corrected distance visual acuity from 0.22 to 0.356 (P = .068). Refractive sphere improved in all patients (from -4.55 diopters [D] to -2.69 D; P = .017), but refractive cylinder remained stable (from -2.83 to -2.61; P = .34). An improvement tendency of all anterior keratometric values was observed. A mean improvement of 120 μm in all thickness parameters was confirmed (P = .008), as well as an improvement in the spherical aberration (P = .018), coma (P = .23) and total higher order aberrations (P = .31). No significant differences among groups were detected.

CONCLUSIONS

Decellularized human corneal stromal laminas transplantation seems safe and moderately effective for advanced keratoconus. Potential benefits of its recellularization with autologous adipose-derived adult stem cells remains unclear.

Hyaluronan Rich Microenvironment in the Limbal Stem Cell Niche Regulates Limbal Stem Cell Differentiation

Purpose

Limbal epithelial stem cells (LSCs), located in the basal layer of the corneal epithelium in the corneal limbus, are vital for maintaining the corneal epithelium. LSCs have a high capacity of self-renewal with increased potential for error-free proliferation and poor differentiation. To date, limited research has focused on unveiling the composition of the limbal stem cell niche, and, more important, on the role the specific stem cell niche may have in LSC differentiation and function. Our work investigates the composition of the extracellular matrix in the LSC niche and how it regulates LSC differentiation and function.

Methods

Hyaluronan (HA) is naturally synthesized by hyaluronan synthases (HASs), and vertebrates have the following three types: HAS1, HAS2, and HAS3. Wild-type and HAS and TSG-6 knockout mice-HAS1-/-;HAS3-/-, HAS2Δ/ΔCorEpi, TSG-6-/--were used to determine the importance of the HA niche in LSC differentiation and specification.

Results

Our data demonstrate that the LSC niche is composed of a HA rich extracellular matrix. HAS1-/-;HAS3-/-, HAS2Δ/ΔCorEpi, and TSG-6-/- mice have delayed wound healing and increased inflammation after injury. Interestingly, upon insult the HAS knock-out mice up-regulate HA throughout the cornea through a compensatory mechanism, and in turn this alters LSC and epithelial cell specification.

Conclusions

The LSC niche is composed of a specialized HA matrix that differs from that present in the rest of the corneal epithelium, and the disruption of this specific HA matrix within the LSC niche leads to compromised corneal epithelial regeneration. Finally, our findings suggest that HA has a major role in maintaining the LSC phenotype.

Surface expression of anti-CD3scfv stimulates locoregional immunotherapy against hepatocellular carcinoma depending on the E1A-engineered human umbilical cord mesenchymal stem cells

Tumor antigens is at the core of cancer immunotherapy, however, the ideal antigen selection is difficult especially in poorly immunogenic tumors. In this study, we designed a strategy to modify hepatocellular carcinoma (HCC) cells by surface expressing anti-CD3scfv within the tumor site strictly, which depended on the E1A-engineered human umbilical cord mesenchymal stem cells (HUMSC.E1A) delivery system. Subsequently, membrane-bound anti-CD3scfv actived the lymphocytes which lysed HCC cells bypassing the expression of antigens or MHC restriction. First, we constructed the anti-CD3scfv gene driven by human α-fetoprotein (AFP) promoter into an adenoviral vector and the E1A gene into the lentiviral vector. Our results showed that anti-CD3scfv could specifically express on the surface of HCC cells and activate the lymphocytes to kill target cells effectively in vitro. HUMSC infected by AdCD3scfv followed by LentiR.E1A could support the adenoviral replication and packaging in vitro 36 h after LentiR.E1A infection. Using a subcutaneous HepG2 xenograft model, we confirmed that AdCD3scfv and LentiR.E1A co-transfected HUMSC could migrate selectively to the tumor site and produce considerable adenoviruses. The new generated AdCD3scfv infected and modified tumor cells successfully. Mice injected with the MSC.E1A.AdCD3scfv and lymphocytes significantly inhibited the tumor growth compared with control groups. Furthermore, 5-fluorouracil (5-FU) could sensitize adenovirus infection at low MOI resulting in improved lymphocytes cytotoxicity in vitro and in vivo. In summary, this study provides a promising strategy for solid tumor immunotherapy.

Liver-Directed Human Amniotic Epithelial Cell Transplantation Improves Systemic Disease Phenotype in Hurler Syndrome Mouse Model

Mucopolysaccharidosis type 1 (MPS1) is an inherited lysosomal storage disorder caused by a deficiency in the glycosaminoglycan (GAG)‐degrading enzyme α‐l‐iduronidase (IDUA). In affected patients, the systemic accumulation of GAGs results in skeletal dysplasia, neurological degeneration, multiple organ dysfunction, and early death. Current therapies, including enzyme replacement and bone marrow transplant, improve life expectancy but the benefits to skeletal and neurological phenotypes are limited. In this study, we tested the therapeutic efficacy of liver‐directed transplantation of a placental stem cell, which possesses multilineage differentiation potential, low immunogenicity, and high lysosomal enzyme activity. Unfractionated human amniotic epithelial cells (hAECs) were transplanted directly into the liver of immunodeficient Idua knockout mouse neonates. The hAECs engraftment was immunohistochemically confirmed with anti‐human mitochondria staining. Enzyme activity assays indicated that hAECs transplantation restored IDUA function in the liver and significantly decreased urinary GAG excretion. Histochemical and micro‐computed tomography analyses revealed reduced GAG deposition in the phalanges joints and composition/morphology improvement of cranial and facial bones. Neurological assessment in the hAEC treated mice showed significant improvement of sensorimotor coordination in the hAEC treated mice compared to untreated mice. Results confirm that partial liver cell replacement with placental stem cells can provide long‐term (>20 weeks) and systemic restoration of enzyme function, and lead to significant phenotypic improvement in the MPS1 mouse model. This preclinical data indicate that liver‐directed placental stem cell transplantation may improve skeletal and neurological phenotypes of MPS1 patients. Stem Cells Translational Medicine2017;6:1583–1594

Cell Therapy of Corneal Diseases

Mesenchymal stem cells isolated from connective tissues are pluripotent and differentiate into phenotypes of connective tissue cell lineages (osteoblasts, chondrocytes, and adipocytes) in vitro and in vivo. They have been used to treat mouse models of connective tissue disease such as lumican-null (Lum) and mucopolysaccharidosis (Gusb) mice. Mesenchymal stem cells have unique immunosuppressive properties allowing evasion of host rejection; thus, they are valuable tools for cell therapy of congenital and acquired diseases involving immune dysfunction of multiple tissues including ocular surface tissues (cornea). We previously showed that human umbilical mesenchymal stem cells (UMSCs) modulated host immune responses, enabling them to survive xenograft transplantation. In vitro, UMSCs modulated inflammatory cells by inhibiting adhesion and invasion, and inducing cell death. UMSCs also regulated M1/M2 macrophage polarization and induced T-regulatory cell maturation from naive intraperitoneal cavity lavage cells. UMSCs exposed to inflammatory cells synthesized a rich extracellular glycocalyx composed of hyaluronan (HA) bound to the heavy chains (HCs) of inter-alpha-trypsin inhibitor (HC-HA), which contains tumor necrosis factor-α-stimulated gene 6 (TSG6) that catalyzes the transfer of HCs to HA, versican, and pentraxin-3. Our in vivo and in vitro results showed that the glycocalyx regulated inflammatory cells, allowing UMSCs to survive host immune rejection. Administration of antibodies against glycocalyx constituents or digestion with hyaluronidase and chondroitinase ABC abolished the UMSCs' ability to modulate immune responses. Treatment with anti-CD44 antibodies also diminished modulation of M2 macrophages by UMSCs, indicating that cell surface CD44 is required for correct UMSC glycocalyx assembly to modulate inflammatory cells.

Treatment of Inherited Eye Defects by Systemic Hematopoietic Stem Cell Transplantation

PURPOSE

Cystinosis is caused by a deficiency in the lysosomal cystine transporter, cystinosin (CTNS gene), resulting in cystine crystal accumulation in tissues. In eyes, crystals accumulate in the cornea causing photophobia and eventually blindness. Hematopoietic stem progenitor cells (HSPCs) rescue the kidney in a mouse model of cystinosis. We investigated the potential for HSPC transplantation to treat corneal defects in cystinosis.

METHODS

We isolated HSPCs from transgenic DsRed mice and systemically transplanted irradiated Ctns-/- mice. A year posttransplantation, we investigated the fate and function of HSPCs by in vivo confocal and fluorescence microscopy (IVCM), quantitative RT-PCR (RT-qPCR), mass spectrometry, histology, and by measuring the IOP. To determine the mechanism by which HSPCs may rescue disease cells, we transplanted Ctns-/- mice with Ctns-/- DsRed HSPCs virally transduced to express functional CTNS-eGFP fusion protein.

RESULTS

We found that a single systemic transplantation of wild-type HSPCs prevented ocular pathology in the Ctns-/- mice. Engraftment-derived HSPCs were detected within the cornea, and also in the sclera, ciliary body, retina, choroid, and lens. Transplantation of HSPC led to substantial decreases in corneal cystine crystals, restoration of normal corneal thickness, and lowered IOP in mice with high levels of donor-derived cell engraftment. Finally, we found that HSPC-derived progeny differentiated into macrophages, which displayed tunneling nanotubes capable of transferring cystinosin-bearing lysosomes to diseased cells.

CONCLUSIONS

To our knowledge, this is the first demonstration that HSPCs can rescue hereditary corneal defects, and supports a new potential therapeutic strategy for treating ocular pathologies.

Corneal surgery in keratoconus: which type, which technique, which outcomes?

Keratoconus is a disease characterized by progressive thinning, bulging, and distortion of the cornea. Advanced cases usually present with loss of vision due to high irregular astigmatism. A majority of these cases require surgical intervention. This review provides an update on the current treatment modalities of corneal surgery available for the management of advanced corneal ectasias.

Extrinsic and Intrinsic Mechanisms by Which Mesenchymal Stem Cells Suppress the Immune System

Mesenchymal stem cells (MSCs) are a group of fibroblast-like multipotent mesenchymal stromal cells that have the ability to differentiate into osteoblasts, adipocytes, and chondrocytes. Recent studies have demonstrated that MSCs possess a unique ability to exert suppressive and regulatory effects on both adaptive and innate immunity in an autologous and allogeneic manner. A vital step in stem cell transplantation is overcoming the potential graft-versus-host disease, which is a limiting factor to transplantation success. Given that MSCs attain powerful differentiation capabilities and also present immunosuppressive properties, which enable them to survive host immune rejection, MSCs are of great interest. Due to their ability to differentiate into different cell types and to suppress and modulate the immune system, MSCs are being developed for treating a plethora of diseases, including immune disorders. Moreover, in recent years, MSCs have been genetically engineered to treat and sometimes even cure some diseases, and the use of MSCs for cell therapy presents new perspectives for overcoming tissue rejection. In this review, we discuss the potential extrinsic and intrinsic mechanisms that underlie MSCs' unique ability to modulate inflammation, and both innate and adaptive immunity.

Mesenchymal stem cells for treating ocular surface diseases

Mesenchymal stem cells (MSC) have become a promising tool for cell therapy in regenerative medicine. They are readily available, demonstrate powerful differentiation capabilities and present immunosuppressive properties that aid them in surviving from host immune rejection for its great potential use in allograft. Currently clinical trials are underway using MSC, both culture-expanded allogeneic and autologous, for the treatment of a range of diseases not treatable by conventional therapies. A vast array of studies has dedicated towards the use of MSC for treating corneal diseases with very promising outcomes. MSC have successfully differentiated into keratocytes both in vitro and in vivo, and corneal epithelial cells in vitro, but it is uncertain if MSC can assume corneal epithelial cells in vivo. However, to date few studies have unequivocally established the efficacy of MSC for treating corneal endothelial defects. Currently, the diversity in protocols of the isolation and expansion of MSC are hindering to the assessment of cell treatment ability and the further development of treatment regimens. Therefore, future studies should develop international standards for MSC isolation and characterization. In this review, we discuss recent advances in MSC for treating ocular surface diseases.

Concise reviews: can mesenchymal stromal cells differentiate into corneal cells? A systematic review of published data

The majority of stem cell therapies for corneal repair are based upon the use of progenitor cells isolated from corneal tissue, but a growing body of literature suggests a role for mesenchymal stromal cells (MSC) isolated from noncorneal tissues. While the mechanism of MSC action seems likely to involve their immuno-modulatory properties, claims have emerged of MSC transdifferentiation into corneal cells. Substantial differences in methodology and experimental outcomes, however, have prompted us to perform a systematic review of the published data. Key questions used in our analysis included: the choice of markers used to assess corneal cell phenotype, the techniques used to detect these markers, adequate reporting of controls, and tracking of MSC when studied in vivo. Our search of the literature revealed 28 papers published since 2006, with half appearing since 2012. MSC cultures established from bone marrow and adipose tissue have been best studied (22 papers). Critically, only 11 studies used appropriate markers of corneal cell phenotype, along with necessary controls. Ten out of these eleven papers, however, contained positive evidence of corneal cell marker expression by MSC. The clearest evidence is observed with respect to expression of markers for corneal stromal cells by MSC. In comparison, the evidence for MSC conversion into either corneal epithelial cells or corneal endothelial cells is often inconsistent or inconclusive. Our analysis clarifies this emerging body of literature and provides guidance for future studies of MSC differentiation within the cornea as well as other tissues.

"GAG-ing with the neuron": The role of glycosaminoglycan patterning in the central nervous system

Proteoglycans (PGs) are a diverse family of proteins that consist of one or more glycosaminoglycan (GAG) chains, covalently linked to a core protein. PGs are major components of the extracellular matrix (ECM) and play critical roles in development, normal function and damage-response of the central nervous system (CNS). GAGs are classified based on their disaccharide subunits, into the following major groups: chondroitin sulfate (CS), heparan sulfate (HS), heparin (HEP), dermatan sulfate (DS), keratan sulfate (KS) and hyaluronic acid (HA). All except HA are modified by sulfation, giving GAG chains specific charged structures and binding properties. While significant neuroscience research has focused on the role of one PG family member, chondroitin sulfate proteoglycan (CSPG), there is ample evidence in support of a role for the other PGs in regulating CNS function in normal and pathological conditions. This review discusses the role of all the identified PG family members (CS, HS, HEP, DS, KS and HA) in normal CNS function and in the context of pathology. Understanding the pleiotropic roles of these molecules in the CNS may open the door to novel therapeutic strategies for a number of neurological conditions.

Bone Marrow Mesenchymal Stem Cell Transplantation in a Rabbit Corneal Alkali Burn Model (A Histological and Immune Histo-chemical Study)

Background

Alkali-burned corneas can seldom heal properly to restore corneal transparency. Treatment of this severe disorder of the ocular surface remains a challenge.

Aim of the Work

was to investigate whether systemically transplanted bone marrow mesenchymal stem cells (BM-MSCs) can promote corneal wound healing after alkali burn.

Material and Methods

Thirty five male New Zealand rabbits were used in this study. The animals were divided into three groups. Group I; the control group was sham operated. Group II; corneal alkali burn was created. Group III; underwent corneal alkali burn then treated with BM-MSCs. All corneas were collected after fourteen and twenty eight days. Evaluation using H&E, PAS & alkaline phosphatase reaction was carried out. Immune histo-chemical staining for CD44 and vimentin was performed as well.

Results

the corneal epithelium of (Group II) showed marked alterations. Vascularization, cellular infiltration and irregularity of the collagen fibers were also seen in the substantia propria. Increase in the thickness of the Descemet’s membrane was noticed as well. On the other hand, at the time of 28 days, Group III rabbits showed best histological results with nearly healed corneas compared to other groups. Meanwhile, vimentin was more strongly expressed in Group III assessing the differentiating ability of BM-MSCs.

Conclusion

BM-MSCs could effectively promote corneal alkali burn healing.

Mucopolysaccharidosis enzyme production by bone marrow and dental pulp derived human mesenchymal stem cells

Mucopolysaccharidoses (MPS) are inherited metabolic disorders that arise from a complete loss or a reduction in one of eleven specific lysosomal enzymes. MPS children display pathology in multiple cell types leading to tissue and organ failure and early death. Mesenchymal stem cells (MSCs) give rise to many of the cell types affected in MPS, including those that are refractory to current treatment protocols such as hematopoietic stem cell (HSC) based therapy. In this study we compared multiple MPS enzyme production by bone marrow derived (hBM) and dental pulp derived (hDP) MSCs to enzyme production by HSCs. hBM MSCs produce significantly higher levels of MPS I, II, IIIA, IVA, VI and VII enzyme than HSCs, while hDP MSCs produce significantly higher levels of MPS I, IIIA, IVA, VI and VII enzymes. Higher transfection efficiency was observed in MSCs (89%) compared to HSCs (23%) using a lentiviral vector. Over-expression of four different lysosomal enzymes resulted in up to 9303-fold and up to 5559-fold greater levels in MSC cell layer and media respectively. Stable, persistent transduction of MSCs and sustained over-expression of MPS VII enzyme was observed in vitro. Transduction of MSCs did not affect the ability of the cells to differentiate down osteogenic, adipogenic or chondrogenic lineages, but did partially delay differentiation down the non-mesodermal neurogenic lineage.

Ectodermal Differentiation of Wharton's Jelly Mesenchymal Stem Cells for Tissue Engineering and Regenerative Medicine Applications

Mesenchymal stem cells (MSCs) from Wharton's jelly (WJ) of the human umbilical cord are perinatal stem cells that have self-renewal ability, extended proliferation potential, immunosuppressive properties, and are accordingly excellent candidates for tissue engineering. These MSCs are unique, easily accessible, and a noncontroversial cell source of regeneration in medicine. Wharton's jelly mesenchymal stem cells (WJMSCs) are multipotent and capable of multilineage differentiation into cells like adipocytes, bone, cartilage, and skeletal muscle upon exposure to appropriate conditions. The ectoderm is one of the three primary germ layers found in the very early embryo that differentiates into the epidermis, nervous system (spine, peripheral nerves, brain), and exocrine glands (mammary, sweat, salivary, and lacrimal glands). Accumulating evidence shows that MSCs obtained from WJ have an ectodermal differentiation potential. The current review examines this differentiation potential of WJMSC into the hair follicle, skin, neurons, and sweat glands along with discussing the potential utilization of such differentiation in regenerative medicine.

Umbilical cord mesenchymal stem cells suppress host rejection: the role of the glycocalyx

Umbilical cord mesenchymal stem cells (UMSCs) have unique immunosuppressive properties enabling them to evade host rejection and making them valuable tools for cell therapy. We previously showed that human UMSCs survive xenograft transplantation and successfully correct the corneal clouding defects associated with the mouse model for the congenital metabolic disorder mucopolysaccharidosis VII. However, the precise mechanism by which UMSCs suppress the immune system remains elusive. This study aimed to determine the key components involved in the ability of the UMSCs to modulate the inflammatory system and to identify the inflammatory cells that are regulated by the UMSCs. Our results show that human UMSCs transplanted into the mouse stroma 24 h after an alkali burn suppress the severe inflammatory response and enable the recovery of corneal transparency within 2 weeks. Furthermore, we demonstrated in vitro that UMSCs inhibit the adhesion and invasion of inflammatory cells and also the polarization of M1 macrophages. UMSCs also induced the maturation of T-regulatory cells and led to inflammatory cell death. Moreover, UMSCs exposed to inflammatory cells synthesize a rich extracellular glycocalyx composed of the chondroitin sulfate-proteoglycan versican bound to a heavy chain (HC)-modified hyaluronan (HA) matrix (HC-HA). This matrix also contains TNFα-stimulated gene 6 (TSG6), the enzyme that transfers HCs to HA, and pentraxin-3, which further stabilizes the matrix. Our results, both in vivo and in vitro, show that this glycocalyx confers the ability for UMSCs to survive the host immune system and to regulate the inflammatory cells.