Bone Marrow-Derived Mononuclear Cell Transplants Decrease Retinal Gliosis in Two Animal Models of Inherited Photoreceptor Degeneration.

Inherited photoreceptor degenerations are not treatable diseases and a frequent cause of blindness in working ages. In this study we investigate the safety, integration and possible rescue effects of intravitreal and subretinal transplantation of adult human bone-marrow-derived mononuclear stem cells (hBM-MSCs) in two animal models of inherited photoreceptor degeneration, the P23H-1 and the Royal College of Surgeons (RCS) rat. Immunosuppression was started one day before the injection and continued through the study. The hBM-MSCs were injected in the left eyes and the animals were processed 7, 15, 30 or 60 days later. The retinas were cross-sectioned, and L- and S- cones, microglia, astrocytes and Müller cells were immunodetected. Transplantations had no local adverse effects and the CD45+ cells remained for up to 15 days forming clusters in the vitreous and/or a 2-3-cells-thick layer in the subretinal space after intravitreal or subretinal injections, respectively. We did not observe increased photoreceptor survival nor decreased microglial cell numbers in the injected left eyes. However, the injected eyes showed decreased GFAP immunoreactivity. We conclude that intravitreal or subretinal injection of hBM-MSCs in dystrophic P23H-1 and RCS rats causes a decrease in retinal gliosis but does not have photoreceptor neuroprotective effects, at least in the short term. However, this treatment may have a potential therapeutic effect that merits further investigation.

Cryopreserved amniotic membrane in the treatment of diabetic foot ulcers: a case series.

OBJECTIVE: The amniotic membrane (AM) is a tissue with low immunogenity and high therapeutic potential due to its anti-inflammatory, anti-fibrotic and antimicrobial effects. This paper describes the use of cryopreserved amniotic membrane allografts to treat diabetic foot ulcers (DFUs) in patients with diabetes. METHOD: In this case series, AM was processed to obtain a final medicinal product: cryopreserved amniotic membrane. cryopreserved AM was applied every 7-10 days until total epithelialisation of the DFUs. RESULTS: A total of 14 patients with DFUs (median size: 12.30cm, (range: 0.52-42.5cm2) were treated and followed up until complete closure (median time: 20 weeks, range: 7-56 weeks). Patients received 4-40 AM applications. All patients in this study achieved complete epithelialisation of the wound. No adverse events were observed. CONCLUSION: AM is a feasible and safe treatment in complex DFUs. Furthermore, the treatment is successful in achieving epithelialisation of long-evolution, unhealed wounds resistant to conventional therapies.

Management of Foot Ulcers and Chronic Wounds with Amniotic Membrane in Comorbid Patients: A Successful Experience.

Chronic wounds are defined as those with disturbances in normal healing. They involve symptoms like exudate, odor, pain or impaired mobility, severely impacting life quality. In the case of patients with additional comorbidities, these are known to aggravate the healing impairment. Amniotic membrane (AM) is gaining attention for its regenerative potential, as it has shown promise in treating hard-to-heal wounds, such as diabetic foot ulcers. This work examines a series of five patients who, while suffering an array of other chronic conditions, were treated with AM for the management of non-healing chronic ulcers. Inclusion criteria involved patients with lesions that have been active at least for six weeks and resistant to multiple treatments, accompanied by complex underlying pathologies affecting cardiovascular, immune or renal functions. Exclusion criteria included untreated active infections and patients undergoing other experimental treatments. The mean age of the patients was 68.4 ± 5.2 years. Wounds were treated once a week with AM, following standardized procedures. The variables measured included pain levels, microorganism presence, wound reduction and the number of AM applications to recovery. The median pain VAS score decreased significantly from seven at the start to two at the end of procedures. Four out of five patients achieved complete epithelialization, while the remaining patient showed significant reductions of 40% in wound size after 14 months. Our results confirm how the application of AM is a safe and effective resource for the management of chronic wounds in patients with serious comorbidities, enhancing patients' quality of life, firstly by reducing pain, later by allowing recovery. Future research, including molecular analyses of wound exudates before and after AM treatment, can contribute to better understanding and fine tuning of this therapeutic resource.

Optimizing cryopreservation conditions for use of fucosylated human mesenchymal stromal cells in anti-inflammatory/immunomodulatory therapeutics.

Mesenchymal stem/stromal cells (MSCs) are being increasingly used in cell-based therapies due to their broad anti-inflammatory and immunomodulatory properties. Intravascularly-administered MSCs do not efficiently migrate to sites of inflammation/immunopathology, but this shortfall has been overcome by cell surface enzymatic fucosylation to engender expression of the potent E-selectin ligand HCELL. In applications of cell-based therapies, cryopreservation enables stability in both storage and transport of the produced cells from the manufacturing facility to the point of care. However, it has been reported that cryopreservation and thawing dampens their immunomodulatory/anti-inflammatory activity even after a reactivation/reconditioning step. To address this issue, we employed a variety of methods to cryopreserve and thaw fucosylated human MSCs derived from either bone marrow or adipose tissue sources. We then evaluated their immunosuppressive properties, cell viability, morphology, proliferation kinetics, immunophenotype, senescence, and osteogenic and adipogenic differentiation. Our studies provide new insights into the immunobiology of cryopreserved and thawed MSCs and offer a readily applicable approach to optimize the use of fucosylated human allogeneic MSCs as immunomodulatory/anti-inflammatory therapeutics.

Enforced mesenchymal stem cell tissue colonization counteracts immunopathology.

Mesenchymal stem/stromal cells (MSCs) are distributed within all tissues of the body. Though best known for generating connective tissue and bone, these cells also display immunoregulatory properties. A greater understanding of MSC cell biology is urgently needed because culture-expanded MSCs are increasingly being used in treatment of inflammatory conditions, especially life-threatening immune diseases. While studies in vitro provide abundant evidence of their immunomodulatory capacity, it is unknown whether tissue colonization of MSCs is critical to their ability to dampen/counteract evolving immunopathology in vivo. To address this question, we employed a murine model of fulminant immune-mediated inflammation, acute graft-versus-host disease (aGvHD), provoked by donor splenocyte-enriched full MHC-mismatched hematopoietic stem cell transplant. aGvHD induced the expression of E-selectin within lesional endothelial beds, and tissue-specific recruitment of systemically administered host-derived MSCs was achieved by enforced expression of HCELL, a CD44 glycoform that is a potent E-selectin ligand. Compared to mice receiving HCELL- MSCs, recipients of HCELL+ MSCs had increased MSC intercalation within aGvHD-affected site(s), decreased leukocyte infiltrates, lower systemic inflammatory cytokine levels, superior tissue preservation, and markedly improved survival. Mechanistic studies reveal that ligation of HCELL/CD44 on the MSC surface markedly potentiates MSC immunomodulatory activity by inducing MSC secretion of a variety of potent immunoregulatory molecules, including IL-10. These findings indicate that MSCs counteract immunopathology in situ, and highlight a role for CD44 engagement in unleashing MSC immunobiologic properties that maintain/establish tissue immunohomeostasis.

Exofucosylation of Adipose Mesenchymal Stromal Cells Alters Their Secretome Profile.

Mesenchymal stromal cells (MSCs) constitute the cell type more frequently used in many regenerative medicine approaches due to their exclusive immunomodulatory properties, and they have been reported to mediate profound immunomodulatory effects in vivo. Nevertheless, MSCs do not express essential adhesion molecules actively involved in cell migration, a phenotypic feature that hampers their ability to home inflamed tissues following intravenous administration. In this study, we investigated whether modification by fucosylation of murine AdMSCs (mAdMSCs) creates Hematopoietic Cell E-/L-selectin Ligand, the E-selectin-binding CD44 glycoform. This cell surface glycan modification of CD44 has previously shown in preclinical studies to favor trafficking of mAdMSCs to inflamed or injured peripheral tissues. We analyzed the impact that exofucosylation could have in other innate phenotypic and functional properties of MSCs. Compared to unmodified counterparts, fucosylated mAdMSCs demonstrated higher in vitro migration, an altered secretome pattern, including increased expression and secretion of anti-inflammatory molecules, and a higher capacity to inhibit mitogen-stimulated splenocyte proliferation under standard culture conditions. Together, these findings indicate that exofucosylation could represent a suitable cell engineering strategy, not only to facilitate the in vivo MSC colonization of damaged tissues after systemic administration, but also to convert MSCs in a more potent immunomodulatory/anti-inflammatory cell therapy-based product for the treatment of a variety of autoimmune, inflammatory, and degenerative diseases.

Amniotic membrane-derived stem cells: immunomodulatory properties and potential clinical application.

Epithelial and mesenchymal cells isolated from the amniotic membrane (AM) possess stem cell characteristics, differentiation potential toward lineages of different germ layers, and immunomodulatory properties. While their expansion and differentiation potential have been well studied and characterized, knowledge about their immunomodulatory properties and the mechanisms involved is still incomplete. These mechanisms have been evaluated on various target cells of the innate and the adaptive system and in animal models of different inflammatory diseases. Some results have evidenced that the immunomodulatory effect of AM-derived cells is dependent on cell-cell contact, but many of them have demonstrated that these properties are mediated through the secretion of suppressive molecules. In this review, we present an update on the described immunomodulatory properties of the derived amniotic cells and some of the proposed involved mechanisms. Furthermore, we describe some assays in animal models of different inflammatory diseases which reveal the potential use of these cells to treat such diseases.