Background:According to WHO, 285 million people are visually impaired out of which, 39 million are classified as blind and the remaining 246 million people have low vision which comprises of moderate vision impairment and severe vision impairment. Therapies to treat major disorders leading to visual impairment like Age-related Macular Degeneration (AMD), Stargardt’s Disease (STGD), Retinitis Pigmentosa (RP) and corneal scarring are required.In the last decade, many advances have been made to treat these disorders using stem cell therapy. For corneal damage by accidental burns, scarring or limbal stem cell deficiencies which can lead to partial or total blindness, are treated with a risky intervention like keratoplasty. To overcome issues like graft rejection caused by keratoplasty as well as have a better outcome, limbal stem cell therapy has been introduced. Similarly, Retinal Pigment Epithelium (RPE) is a supporting tissue essential in nutrient transport, production of growth factors, phagocytosis of the photoreceptors and retinol cycling.Discussion and Conlusion:Degeneration of this monolayer causes many diseases that have no prevailing treatment; however, research is being carried out to replace this simple epithelial monolayer primarily with an autologous source of cells and currently using stem cells. This review discusses the advances made in the field of ocular stem cell therapy with regards to development, cultivation and novel methods used to deliver these cells to replace the corneal and retinal epithelium as a new standard for treatment.

Background:Osteosarcoma cancer stem cells (CSCs) are defined as a subpopulation of osteosarcoma cells, which have the ability of self-renewal, proliferation and differentiation. This study aimed to identify CSCs from human osteosarcomain vitro.Methods:Osteosarcoma CSCs were isolated and cultured with sphere-forming assay technique on an ultra-low well attachment surface plate. After sarcosphere colonies were formed, we conducted reverse transcriptase-polymerase chain reaction (RT-PCR) to detect the expression of genes of embryonic stem cells such asNANOG, Oct3/4, STAT3 and gene of MSC CD133. Immunofluorescence analysis (IFA) of alkaline phosphatase (ALP), osteocalcin, and CD 133 was also performed to see the expression of osteosarcoma CSC surface protein with immuno-enzymatic staining principle. We also performed alizarin red staining to evaluate calcification in osteosarcoma CSCs.Results:The culture sphere-of the osteosarcoma cells showed three dimension round shaped colonies (sarcospheres) in slightly hypoxicand serum free condition which was not attached to the substrate with tight density. RT-PCR demonstrated that sarcospheres expressed genes which encodeNANOG, Oct3/4 STAT 3, but not for CD 133. IFA showed positive protein expression of ALP, osteocalcin and CD 133 which was moderate, strong, and weak positive respectively. Sarcospheres also had a positive reaction toward alizarin red staining.Conclusion:Osteosarcoma CSCs could be isolated from human osteosarcoma by sphere-forming assay technique and characterized by the expression of genes of embryonic stem cells,such asNANOG, Oct3/4, STAT3 and IFA of ALP, osteocalcin, and CD 133.

The preservation of the genetic and epigenetic integrity of human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs) during in vitro propagation is critical for their use in both research and future therapeutic applications. It has been reported that hESCs and iPSCs have the ability to adapt to various culture conditions. However, human pluripotent stem cells cultured in serum free media can frequently accumulate point mutations, aneuploidy, and progressive epigenetic changes over prolonged culture in vitro for reasons that are poorly understood. The phenotypic and epigenetic changes brought about by the culture conditions can have significant impacts on their use in research and in clinical applications. An increased understanding of the potential effects of in vitro culture environments on pluripotent stem cell growth can enhance the development of improved culture systems for hESCs or iPSCs, and facilitate any future therapeutic applications using these cells. In this review, we first focus on the occurrence, potential causes and consequences of genetic and epigenetic unstable human pluripotent stem cells in vitro. We further discuss the current methods for detection and characterization of abnormal pluripotent stem cells that involve simply traditional karyotype analysis. All these observations highlight the need for novel screening strategies to determine the safety of hESCs or iPSCs and optimization and standardization of procedures for the generation and culture of pluripotent stem cells that minimize culture-induced epigenetic and genetic instability.

Human type 1 diabetes mellitus occurs due to chronic inflammation with lymphocytic infiltration and (usually) the presence of antibodies against insulin and characteristic islet cell proteins (e.g., GAD). This autoimmune process destroys the islets of Langerhans (including the beta cells) leading to insulin insufficiency. In several studies to date diabetes in the non-obese diabetic (NOD) mouse model of human type 1 diabetes has either been prevented or reversed by allogeneic transplantation of stem cells derived from mouse bone marrow or spleen. Immunosuppressive regimens have been ablative in some studies, but non-ablative regimes have been used in others. With non-ablative regimens, recipient mice develop chimeric immune systems. In addition, two recent clinical trials using stem cells have shown similar benefit for human patients with type 1 diabetes. We investigated whether stem cells isolated from genetically identical, but non-diabetic neonatal mouse pups (i.e., the mouse equivalent of human cord blood stem cells) would reverse diabetes when transfused into NOD mouse recipients which have already developed hyperglycemia. It was observed that cord blood stem cell infusion after diabetic conversion resulted in reversal of hyperglycemia whether given with or without the immune ablative drug, cytoxan. However, cytoxan alone had no beneficial effect. Stem cell-treated mice also lived longer than untreated mice. In these studies it was not possible to demonstrate islet cell regeneration resulting from the infused stem cells. These experiments provide evidence that cord blood stem cells may be suitable for improving or eliminating the autoimmune process in human type 1 diabetes patients, and thereby modulating their disease. However, additional studies are needed to clarify the mechanisms behind these observations.

The extracellular matrix provides structural and organizational cues for tissue development and defines and maintains cellular phenotype during cell fate determination. Multipotent mesenchymal stem cells use this matrix to tightly regulate the balance between their differentiation potential and self-renewal in the native niche. When understood, the mechanisms that govern cell-matrix crosstalk during differentiation will allow for efficient engineering of natural and synthetic matrices to specifically direct and maintain stem cell phenotype. This work identifies the discoidin domain receptor 1 (DDR1), a collagen activated receptor tyrosine kinase, as a potential link through which stem cells sense and respond to the 3D organization of their extracellular matrix microenvironment. DDR1 is dependent upon both the structure and proteolytic state of its collagen ligand and is specifically expressed and localized in three dimensional type I collagen culture. Inhibition of DDR1 expression results in decreased osteogenic potential, increased cell spreading, stress fiber formation and ERK1/2 phosphorylation. Additionally, loss of DDR1 activity alters the cell-mediated organization of the naïve type I collagen matrix. Taken together, these results demonstrate a role for DDR1 in the stem cell response to and interaction with three dimensional type I collagen. Dynamic changes in cell shape in 3D culture and the tuning of the local ECM microstructure, directs crosstalk between DDR1 and two dimensional mechanisms of osteogenesis that can alter their traditional roles.