Therapeutic Effect of Human Adipose Tissue-Derived Mesenchymal Stem Cells in Experimental Corneal Failure Due to Limbal Stem Cell Niche Damage

Producción CientíficaLimbal stem cells are responsible for the continuous renewal of the corneal epithelium. The destruction or dysfunction of these stem cells or their niche induces limbal stem cell deficiency (LSCD) leading to visual loss, chronic pain, and inflammation of the ocular surface. To restore the ocular surface in cases of bilateral LSCD, an extraocular source of stem cells is needed to avoid dependence on allogeneic limbal stem cells that are difficult to obtain, isolate, and culture. The aim of this work was to test the tolerance and the efficacy of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) to regenerate the ocular surface in two experimental models of LSCD that closely resemble the different severity grades of the human pathology. hAT-MSCs transplanted to the ocular surface of the partial and total LSCD models developed in rabbits were well tolerated, migrated to inflamed tissues, reduced inflammation, and restrained the evolution of corneal neovascularization and corneal opacity. The expression profile of the corneal epithelial cell markers CK3 and E-cadherin, and the limbal epithelial cell markers CK15 and p63 was lost in the LSCD models, but was partially recovered after hAT-MSC transplantation. For the first time, we demonstrated that hAT-MSCs improves corneal and limbal epithelial phenotypes in animal LSCD models. These results support the potential use of hAT-MSCs as a novel treatment of ocular surface failure due to LSCD. hAT-MSCs represent an available, non-immunogenic source of stem cells that may provide therapeutic benefits in addition to reduce health care expenses.This work was supported by Instituto de Salud Carlos III, CIBER‐BBN, Spain (CB06/01/003 MINECO/FEDER, EU); Regional Center for Regenerative Medicine and Cell Therapy, Castilla y León, Spain; Ministry of Science and Innovation, Spain (SAF2010–14900); Ministry of Economy and Competitiveness and European Regional Development Fund, Spain (SAF2015–63594‐R MINECO/FEDER, EU

Age and sex-adjusted reference intervals in tear cytokine levels in healthy subjects

Producción CientíficaAlterations in tear cytokine levels have been associated with various ocular disorders as compared to those in healthy subjects. However, age and sex are not always considered in these comparisons. In this study we aimed to establish age and sex reference intervals (RIs) for tear cytokine levels in healthy people. Tear samples were taken from 75 males and 82 females, aged 18–88 years, and tear cytokine levels were determined. Age- and sex-adjusted RIs for epidermal growth factor (EGF), fractalkine, interleukin (IL)-1 receptor antagonist (RA), IL-7, IL-8, interferon inducible protein (IP)-10, monocyte chemotactic protein (MCP)-1, and vascular endothelial growth factor (VEGF) tear cytokine levels in a healthy sample were established using generalized additive for location, scale and shape (GAMLSS) models. RIs were tested in two external samples: a validation sample of 40 individuals with normal results at four Dry Eye Disease (DED) clinical diagnostic tests (OSDI, T-BUT, corneal staining and Schirmer test); and a utility sample of 13 severe DED cases. IL-1RA, IL-8, IP-10, and MCP-1 levels showed a positive association with age, while EGF was negatively correlated. IL-7 concentration increased up to 40 years and again after 70 years, observing a quasi-linear decrease between them. For VEGF, higher levels were observed in the middle-aged range. Regarding sex-influence, fractalkine tear levels were higher in men, whereas those of IL-7, IL-8, and IP-10 were higher in women. Using the estimated age- and sex-adjusted RIs, more than 92% of the validation sample was correctly classified, and 100% of the severe DED patients in the utility sample had concentrations outside the RIs in at least two of the cytokines evaluated

A proof-of-concept clinical trial using mesenchymal stem cells for the treatment of corneal epithelial stem cell deficiency

Producción CientíficaOcular stem cell transplantation derived from either autologous or allogeneic donor corneoscleral junction is a functional cell therapy to manage extensive and/or severe limbal stem cell deficiencies that lead to corneal epithelial failure. Mesenchymal stem cells have been properly tested in animal models of this ophthalmic pathology, but never in human eyes despite their potential advantages. We conducted a 6- to 12-month proof-of-concept, randomized, and double-masked pilot trial to test whether allogeneic bone marrow-derived mesenchymal stem cell transplantation (MSCT], n = 17) was as safe and as equally efficient as allogeneic cultivated limbal epithelial transplantation (CLET), (n = 11) to improve corneal epithelial damage due to limbal stem cell deficiency. Primary endpoints demanded combination of symptoms, signs, and the objective improvement of the epithelial phenotype in central cornea by in vivo confocal microscopy. This proof-of-concept trial showed that MSCT was as safe and efficacious as CLET. Global success at 6–12 months was 72.7%–77.8% for CLET cases and 76.5%–85.7% for MSCT cases (not significant differences). Central corneal epithelial phenotype improved in 71.4% and 66.7% of MSCT and CLET cases, respectively at 12 months (P = 1.000). There were no adverse events related to cell products. This trial suggests first evidence that MSCT facilitated improvement of a diseased corneal epithelium due to lack of its stem cells as efficiently as CLET. Consequently, not only CLET but also MSCT deserves more preclinical investigational resources before the favorable results of this proof-of-concept trial could be transformed into the larger numbers of the multicenter trials that would provide stronger evidence. (ClinicalTrials.gov number, NCT01562002.)Ministerio de Sanidad, Consumo y Bienestar Social (project SAS/2481/2009)Centro en Red de Medicina Regenerativa y Terapia Celular de Castilla y León (grant SAN 1178/200)Red de Terapia Celular TerCel (project RD12/0019/0036

Eficacia del trasplante de células madre mesenquimales de médula ósea y de tejido adiposo en un modelo de deficiencia de células madre limbares desarrollado en conejo: estudio comparativo

INTRODUCCIÓN: La deficiencia de células madre limbares (LSCD, por sus siglas en inglés) se produce como resultado de la destrucción y/o disfunción de las células madre del epitelio limbar, y tiene entre sus consecuencias la pérdida de visión y la inflamación crónica de la superficie ocular. Nuestro grupo de investigación ha demostrado recientemente que el trasplante de células madre mesenquimales (MSC) derivadas de la médula ósea (BM-MSC) en la superficie ocular de pacientes que padecen LSCD es seguro y facilita de manera eficaz la reparación del epitelio corneal. Sin embargo, las MSC derivadas del tejido adiposo (AT-MSC) se ha demostrado que son más accesibles, más económicas y una fuente de células madre más segura que las BM-MSC. OBJETIVO: Comparar la eficacia del trasplante de BM-MSC versus AT-MSC en un modelo de LSCD desarrollado en conejo. MÉTODOS: Dieciocho conejos fueron tratados con 250.000 MSC cultivadas sobre una membrana amniótica (9 con BM-MSC y 9 con AT-MSC) y trasplantadas tres semanas después de inducirles un LSCD. Mediante desepitelización completa de la córnea con n-heptanol, seguida de una peritomía limbar quirúrgica de 360º, se indujo un modelo de LSCD en 27 conejos. Transcurridas 3 semanas de evolución, 18 conejos fueron trasplantados con 250.000 MSC cultivadas sobre una membrana amniótica (9 con BM-MSC y 9 con AT-MSC). Nueve conejos no trasplantados formaron el grupo de control. Semanalmente, se evaluó clínicamente la invasión conjuntival, la neovascularización, la opacidad y el defecto epitelial corneal con una lámpara de hendidura. Mediante un análisis histopatológico realizado al final del periodo del seguimiento (11 semanas), se evaluó el nivel de daño tisular y la presencia de linfocitos (como signo de inflamación) y de células caliciformes (como signo de conjuntivalización) en el limbo y en la córnea. RESULTADOS: El grupo trasplantado con BM-MSC mostró menos neovascularización y menos opacidad corneal en las semanas 6-8 y 6-9, respectivamente, que el grupo no tratado. El grupo tratado con AT-MSC tuvo menos invasión conjuntival y opacidad corneal en las semanas 6-8 y 6-10, respectivamente, que el grupo de control. No hubo diferencias en los defectos epiteliales entre los 3 grupos. Los grupos trasplantados con BM-MSC y AT-MSC mostraron un mayor número de capas epiteliales en la córnea y en el limbo, menos desorganización del estroma, menor cantidad de células inflamatorias en el estroma de la córnea y menos células caliciformes en el epitelio del limbo y/o de la córnea que el grupo no tratado. CONCLUSIONES: El trasplante de BM-MSC y AT-MSC en un modelo de LSCD desarrollado en conejo redujo el desarrollo de la opacidad corneal y restauró parcialmente la estructura dañada del tejido limbar y corneal. Las BM-MSC fueron mejores en la reducción del desarrollo de la neovascularización corneal, mientras que las AT-MSC evitaron mejor la invasión conjuntival. Ambos tipos de MSC parecen alternativas válidas para el tratamiento de la LSCD.Ministerios de Economía y Competitividad (SAF2015-63594-R MINECO/FEDER, UE) y de Ciencia e Innovación, España (SAF2010-14900); Instituto de Salud Carlos III, España (CIBER-BBN, CB06/01/003 MINECO/FEDER). Centro en Red de Medicina Regenerativa y Terapia Celular de Castilla y León, España

Successful consecutive expansion of limbal explants using a biosafe culture medium under feeder layer-free conditions

Producción CientíficaPurpose: Transplantation of in vitro cultured limbal epithelial stem cells (LESCs) is a treatment widely used for LESC deficiency. However, the number of limbal tissue donors is limited, and protocols for LESC cultivation often include compounds and/or feeder layers that can induce side effects and/or increase the cost of the culture procedure. We investigated the feasibility of obtaining more than one limbal primary culture (LPC) from the same biopsy using a culture medium in which several potentially harmful compounds were replaced at the same time by biosafe supplements, allowing the LESC cultivation without feeder layers. Materials and methods: We established feeder layer-free LPCs with three culture media: (1) a modified supplemental hormonal epithelial medium, containing potential harmful components (cholera toxin, dimethylsulfoxide, and fetal bovine serum [FBS]), (2) IOBA-FBS, a medium with FBS but with no other harmful supplements, and (3) IOBA-HS, similar to IOBA-FBS but with human serum instead of FBS. Additionally, the same limbal explant was consecutively cultured with IOBA-HS producing three cultures. LPCs were characterized by real-time reverse transcription polymerase chain reaction and/or immunofluorescence. Results: LPCs cultured with the three media under feeder layer-free conditions showed cuboidal cells and no significant differences in the percentage of positive cells for limbal (ABCG2, p63, and K14) and corneal (K3, K12) proteins. Except for ABCG2, the relative mRNA expression of the LESC markers was significantly higher when IOBA-FBS or IOBA-HS was used. LPC1 showed characteristics similar to LPC0, while LPC2 cell morphology became elongated and the expression of some LESC markers was diminished. Conclusion: IOBA-HS enables the culturing of up to two biosafe homologous LPCs from one limbal tissue under feeder layer-free conditions. The routine use of this culture medium could improve both the biosafety and the number of available LPCs for potential clinical transplantation, as well as decrease the expense of the culture procedure.This work was supported by the Carlos III National Health Institute (CIBER-BBN and Spanish Network on Cell Therapy: ([grant number TerCel, RD12/0019/0036], Spain) and the Castilla-León Government (Regional Center for Regenerative Medicine and Cell Therapy: [grant numbers SAN126/VA11/09 and BIO/VA05/15). M. López-Paniagua and S. Galindo were supported by scholarships cofinanced by the Castilla-León Government and the European-Social-Fond

Subconjunctival injection of mesenchymal stem cells for corneal failure due to limbal stem cell deficiency: state of the art

Producción CientíficaMesenchymal stem cells (MSCs) have unique and beneficial properties and are currently used to treat a broad variety of diseases. These properties include the potential for differentiation into other cell types, secretion of different trophic factors that promote a regenerative microenvironment, anti-inflammatory actions, selective migration to damaged tissues, and non-immunogenicity. MSCs are effective for the treatment of ocular surface diseases such as dry eye, corneal burns, and limbal stem cell deficiency (LSCD), both in experimental models and in humans. LSCD is a pathological condition in which damage occurs to the limbal epithelial stem cells, or their niche, that are responsible for the continuous regeneration of the corneal epithelium. If LSCD is extensive and/or severe, it usually causes corneal epithelial defects, ulceration, and conjunctival overgrowth of the cornea. These changes can result in neovascularization and corneal opacity, severe inflammation, pain, and visual loss. The effectiveness of MSCs to reduce corneal opacity, neovascularization, and inflammation has been widely studied in different experimental models of LSCD and in some clinical trials; however, the methodological disparity used in the different studies makes it hard to compare outcomes among them. In this regard, the MSC route of administration used to treat LSCD and other ocular surface diseases is an important factor. It should be efficient, minimally invasive, and safe. So far, intravenous and intraperitoneal injections, topical administration, and MSC transplantation using carrier substrata like amniotic membrane (AM), fibrin, or synthetic biopolymers have been the most commonly used administration routes in experimental models. However, systemic administration carries the risk of potential side effects and transplantation requires surgical procedures that could complicate the process. Alternatively, subconjunctival injection is a minimally invasive and straightforward technique frequently used in ophthalmology. It enables performance of local treatments using high cell doses. In this review, we provide an overview of the current status of MSC administration by subconjunctival injection, analyzing the convenience, safety, and efficacy for treatment of corneal failure due to LSCD in different experimental models. We also provide a summary of the clinical trials that have been completed, are in progress, or being planned.Consejería de Educación, Junta de Castilla y León (Proyecto VA268P18 FEDER, EU); Ministerio de Ciencia e Innovación (Proyecto PID2019-105525RB-100, MICINN/FEDER);Instituto de Saludo Carlos III, CIBER-BBN (CB06/01/003 MICINN/FEDER, EU); Centro en Red de Medicina Regenerativa y Terapia Celular de Castilla y León

Stem Cell Therapy for Corneal Epithelium Regeneration following Good Manufacturing and Clinical Procedures

Producción CientíficaObjective. To evaluate outcomes of cultivated limbal epithelial transplantation (CLET) for management of ocular surface failure due to limbal stem cell deficiency (LSCD). Design. Prospective, noncomparative, interventional case series and extensive comparison with recent similar studies. Participants. Twenty eyes with LSCD underwent CLET (11 autologous; 9 allogeneic) and were followed up for 3 years. Etiologies were divided into 3 prognostic categories: Group 1, chemical injuries (7 eyes); Group 2, immune-based inflammation (4 eyes); and Group 3, noninflammatory diseases (9 eyes). Intervention. Autologous and allogeneic limbal epithelial cells were cultivated on amniotic membranes and transplanted. Evaluations were based on clinical parameters, survival analysis, and in vivo confocal microscopy (IVCM). European Union Tissues/Cells Directive and good manufacturing procedures were followed. Main Outcome Measures. Improved clinical parameters, absence of epithelial defects, and improved central corneal epithelial phenotype. Results. Success rate was 80% at 1-2 years and 75% at 3 years. Autografts and allografts had similar survival. Success rate was significantly lower in prognostic Group 1 (42.9%) than in Groups 2-3 (100% each). All clinical parameters improved substantially. By IVCM, 80% of cases improved in epithelial status. Conclusions. CLET improved corneal epithelium quality, with subsequent improvement in symptoms, quality of life, and vision. These results confirm that CLET is a valid therapy for ocular surface failure.This study received a financial support from the Advanced Therapies Program (SAS/2481/2009), Ministry of Health, Spain; Regional Center for Regenerative Medicine and Cell Therapy, SAN 1178/200, Castilla y León, Spain. Beatriz E. Ramírez held a predoctoral scholarship from The Carolina Foundation, Ministry of Foreign Affairs, Spain

Tear and Plasma Levels of Cytokines in Patients with Uveitis: Search for Active Disease Biomarkers

Uveitis accounts for up to 20% of blindness in Europe, making the development of new non-invasive biomarkers which could help in its management a field of interest. It has been hypothesised that tear levels of cytokines and chemokines could be used as a potential biomarker in patients with anterior uveitis, and this could be correlated with their concentration in plasma. Therefore, we measured twelve cytokines/chemokines in tear and plasma samples of 22 patients diagnosed with active anterior uveitis. Levels of these molecules in tears and plasma were compared and associated with the degree of activity of the uveitis. It is notable that the percentage of tear interleukin (IL)-6 detection was significantly reduced in the inactive phase (p p < 0.05) from the counterpart levels in plasma. In conclusion, no isolated cytokine/chemokine in the tears has been found in a concentration which could be used as a potential biomarker of disease activity and treatment response

XXXI Congreso Nacional de Técnico Superior en Laboratorio Clínico y Biomédico y Técnico Superior en Anatomía Patológica y Citodiagnóstico. "Técnicas de Inmunoterapia: nuevos retos y oportunidades"".

Producción CientíficaINTRODUCCIÓN: En el denominado “limbo esclero-corneal” se localizan las células madre responsables de la regeneración continua del epitelio corneal. Cuando se produce una disfunción o pérdida de estas células madre limbares se desarrolla el conocido como Síndrome de Insuficiencia Límbica (SIL), patología que se caracteriza por la invasión de la conjuntiva sobre la córnea y por la aparición de defectos epiteliales, neovascularización y opacidad corneal; todo ello acompañado de inflamación persistente, dolor crónico y pérdida de visión. Actualmente, la reparación del epitelio de la superficie ocular afectada por el SIL es un gran desafío. En los últimos años, las células madre mesenquimales (“mesenchymal stem cells”, MSCs) derivadas de médula ósea (MO) han adquirido gran importancia por sus propiedades terapéuticas y antiinflamatorias, así como por su escasa inmunogenicidad. En el presente trabajo se pretende estudiar la capacidad terapéutica de las MSCs-MO humanas en el tratamiento del SIL. OBJETIVO: Estudiar la tolerabilidad y la eficacia del trasplante de MSCs-MO humanas en un modelo de SIL desarrollado en conejo. MATERIALES Y MÉTODOS: Se indujo un SIL total en 16 conejos. Para ello, en el ojo derecho de cada animal se realizó una desepitelización completa de la córnea con n-heptanol, seguida de una peritomía limbar quirúrgica de 360º. Semanalmente, se evaluó la conjuntivalización, la neovascularización, la opacidad y el defecto epitelial corneal, utilizando una escala de valoración de 0 a 4 (de menor a mayor severidad). Transcurridas 3 semanas de evolución, a 7 de los 16 conejos se les implantó una membrana amniótica con 250.000 MSCs-MO humanas marcadas con 5’-bromo-2’-desoxiuridina (BrdU). Al final del periodo de seguimiento (semana 11), todos los conejos fueron sacrificados y se recogieron los globos oculares para realizar un estudio histológico. Los tejidos se fijaron, se incluyeron en parafina, se realizaron cortes en el micrótomo y se tiñeron con la técnica de tinción de PAS (Periodic Acid-Schiff) para estudiar la estructura tisular y la presencia de células inflamatorias y de células caliciformes (específicas de la conjuntiva) en el limbo y en la córnea. RESULTADOS: Se observó que la neovascularización y la opacidad corneal fueron significativamente menores durante las semanas 6, 7 y 8 en el grupo de animales trasplantados con las MSCs-MO en comparación con el grupo de animales sin tratamiento. En cambio, no se observaron diferencias estadísticamente significativas en la conjuntivalización y en los defectos epiteliales entre el grupo de animales trasplantados con las MSCs-MO y el grupo de animales sin tratamiento. A nivel histológico, el limbo y la córnea de los animales tratados con MSCs-MO mostraron mayor número de capas epiteliales y un estroma más organizado que los animales no tratados. Además, los animales tratados con MSCs-MO presentaron menor cantidad de células caliciformes (propias de la conjuntiva) en el epitelio limbar y menor presencia de células inflamatorias (linfocitos) en el estroma corneo-limbar. CONCLUSIONES: El trasplante de MSCs-MO humanas en la superficie ocular de conejos con SIL es bien tolerado, disminuye la neovascularización, la opacidad y la inflamación corneal, y restablece parcialmente la estructura tisular de la córnea y el limbo dañados. Por lo tanto, las MSCs-MO podrían constituir una terapia eficaz para el tratamiento de pacientes con SIL.Ministerio de Economía y Competitividad (SAF2015-63594-R MINECO/FEDER, UE); Instituto de Salud Carlos III, España (CIBER-BBN, CB06/01/003 MINECO/FEDER). Centro de Medicina Regenerativa y Terapia Celular, de Castilla y León, España

Comparison of functional limbal epithelial stem cell isolation methods

Producción CientíficaThe transplantation of limbal epithelial stem cells (LESCs) cultured in vitro is a great advance in the treatment of patients suffering from LESC deficiency. However, the optimal technique for LESC isolation from a healthy limbal niche has not yet been established. Our aim was to determine which isolation method renders the highest recovery of functional LESCs from the human limbus. To achieve this purpose, we compared limbal primary cultures (LPCs) obtained from explants and cell suspensions on plastic culture plates. Cell morphology was observed by phase contrast and transmission electron microscopy. LESC, corneal epithelial cell, fibroblast, endothelial cell, melanocyte, and dendritic cell markers were analyzed by real time by reverse transcription polymerase chain reaction and/or immunofluorescence. In addition, colony forming efficiency (CFE) and the presence of holoclones, meroclones, and paraclones were studied. We observed that LPC cells obtained from both methods had cuboidal morphology, desmosomes, and prominent intermediate filaments. The expression of LESC markers (K14, K15, ABCG2, p63α) was similar or higher in LPCs established through cell suspensions, except the expression of p63α mRNA, and there were no significant differences in the expression of corneal epithelial markers (K3, K12). Endothelial cell (PECAM), melanocyte (MART-1), and dendritic cell (CD11c) proteins were not detected, while fibroblast-protein (S100A4) was detected in all LPCs. The CFE was significantly higher in LPCs from cell suspensions. Cells from confluent LPCs produced by explants generated only paraclones (100%), while the percentage of paraclones from LPCs established through cell suspensions was 90% and the remaining 10% were meroclones. In conclusion, LPCs established from cell suspensions have a cell population richer in functional LESCs than LPCs obtained from explants. These results suggest that in a clinical situation in which it is possible to choose between either of the isolation techniques from the donor limbal tissue, then the cell suspension is probably the best option as long as the cells are expanded following our culture conditions.This work was supported by the CIBER-BBN (Network Center in Biomedical Research-Biomaterials, Bioengineering, Nanomedicine), Carlos III National Health Institute, and Regional Center for Regenerative Medicine and Cell Therapy of Castile and Leon. Marina López-Paniagua and Sara Galindo were supported by scholarships co-financed by the Castile and Leon Government and the European-Social-Fund