Microencapsulation of dopamine neurons derived from human induced pluripotent stem cells

Natural Biopolymers as Additional Tools for Cell Microencapsulation Applied to Cellular Therapy

One of the limitations in organ, tissue or cellular transplantations is graft rejection. To minimize or prevent this, recipients must make use of immunosuppressive drugs (IS) throughout their entire lives. However, its continuous use generally causes several side effects. Although some IS dose reductions and withdrawal strategies have been employed, many patients do not adapt to these protocols and must return to conventional IS use. Therefore, many studies have been carried out to offer treatments that may avoid IS administration in the long term. A promising strategy is cellular microencapsulation. The possibility of microencapsulating cells originates from the opportunity to use biomaterials that mimic the extracellular matrix. This matrix acts as a support for cell adhesion and the syntheses of new extracellular matrix self-components followed by cell growth and survival. Furthermore, by involving the cells in a polymeric matrix, the matrix acts as an immunoprotective barrier, protecting cells against the recipient’s immune system while still allowing essential cell survival molecules to diffuse bilaterally through the polymer matrix pores. In addition, this matrix can be associated with IS, thus diminishing systemic side effects. In this context, this review will address the natural biomaterials currently in use and their importance in cell therapy.

Informatics Approaches for Harmonized Intelligent Integration of Stem Cell Research

As biomedical data integration and analytics play an increasing role in the field of stem cell research, it becomes important to develop ways to standardize, aggregate, and share data among researchers. For this reason, many databases have been developed in recent years in an attempt to systematically warehouse data from different stem cell projects and experiments at the same time. However, these databases vary widely in their implementation and structure. The aim of this scoping review is to characterize the main features of available stem cell databases in order to identify specifications useful for implementation in future stem cell databases. We conducted a scoping review of peer-reviewed literature and online resources to identify and review available stem cell databases. To identify the relevant databases, we performed a PubMed search using relevant MeSH terms followed by a web search for databases which may not have an associated journal article. In total, we identified 16 databases to include in this review. The data elements reported in these databases represented a broad spectrum of parameters from basic socio-demographic variables to various cells characteristics, cell surface markers expression, and clinical trial results. Three broad sets of functional features that provide utility for future stem cell research and facilitate bioinformatics workflows were identified. These features consisted of the following: common data elements, data visualization and analysis tools, and biomedical ontologies for data integration. Stem cell bioinformatics is a quickly evolving field that generates a growing number of heterogeneous data sets. Further progress in the stem cell research may be greatly facilitated by development of applications for intelligent stem cell data aggregation, sharing and collaboration process.

Chemically defined conditions for long-term maintenance of pancreatic progenitors derived from human induced pluripotent stem cells

Large numbers of hormone-releasing cells, approximately 10⁹ endocrine cells, are required to treat type I diabetes patients by cell transplantation. The SOX9-positive pancreatic epithelium proliferates extensively during the early stages of pancreatic development. SOX9-positive pancreatic epithelium is thought to be an expandable cell source of β cells for transplantation therapy. In this study, we attempted to expand pancreatic progenitors (PPs: PDX1⁺/SOX9⁺) derived from four human iPSC lines in three-dimensional (3D) culture using a chemically defined medium and examined the potential of the derived PPs to differentiate into β-like cells. PPs from four human iPSC lines were maintained and effectively proliferated in a chemically defined medium containing epidermal growth factor and R-spondin-1, CHIR99021, fibroblast growth factor-7, and SB431542. PPs derived from one iPSC line can be expanded by more than 10⁴-fold in chemically defined medium containing two of the fives, epidermal growth factor and R-spondin-1. The expanded PPs were also stable following cryopreservation. After freezing and thawing, the PPs proliferated without a decrease in the rate. PPs obtained after 50 days of culture successfully differentiated into insulin-positive β-like cells, glucagon-positive α-like cells, and somatostatin-positive δ-like cells. The differentiation efficiency of expanded PPs was similar to that of PPs without expansion culture.

Preservation and stability of cell therapy products: recommendations from an expert workshop

If the field of regenerative medicine is to deliver therapies, rapid expansion and delivery over considerable distances to large numbers of patients is needed. This will demand efficient stabilization and shipment of cell products. However, cryopreservation science is poorly understood by life-scientists in general and in recent decades only limited progress has been made in the technology of preservation and storage of cells. Rapid translation of new developments to a broader range of cell types will be vital, as will assuring a deeper knowledge of the fundamental cell biology relating to successful preservation and recovery of cell cultures. This report presents expert consensus on these and other issues which need to be addressed for more efficient delivery of cell therapies.

Long-term maintenance of human induced pluripotent stem cells by automated cell culture system

Pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem (iPS) cells, are regarded as new sources for cell replacement therapy. These cells can unlimitedly expand under undifferentiated conditions and be differentiated into multiple cell types. Automated culture systems enable the large-scale production of cells. In addition to reducing the time and effort of researchers, an automated culture system improves the reproducibility of cell cultures. In the present study, we newly designed a fully automated cell culture system for human iPS maintenance. Using an automated culture system, hiPS cells maintained their undifferentiated state for 60 days. Automatically prepared hiPS cells had a potency of differentiation into three germ layer cells including dopaminergic neurons and pancreatic cells.

Stem cells - biological update and cell therapy progress

In recent years, the advances in stem cell research have suggested that the human body may have a higher plasticity than it was originally expected.

Until now, four categories of stem cells were isolated and cultured in vivo: embryonic stem cells, fetal stem cells, adult stem cells and induced pluripotent stem cells (hiPSCs).

Although multiple studies were published, several issues concerning the stem cells are still debated, such as: the molecular mechanisms of differentiation, the methods to prevent teratoma formation or the ethical and religious issues regarding especially the embryonic stem cell research.

The direct differentiation of stem cells into specialized cells: cardiac myocytes, neural cells, pancreatic islets cells, may represent an option in treating incurable diseases such as: neurodegenerative diseases, type I diabetes, hematologic or cardiac diseases.

Nevertheless, stem cell-based therapies, based on stem cell transplantation, remain mainly at the experimental stages and their major limitation is the development of teratoma and cancer after transplantation. The induced pluripotent stem cells (hiPSCs) represent a prime candidate for future cell therapy research because of their significant self-renewal and differentiation potential and the lack of ethical issues.

This article presents an overview of the biological advances in the study of stem cells and the current progress made in the field of regenerative medicine.

Maturation of human iPS cell-derived dopamine neuron precursors in alginate-Ca(2+) hydrogel

BACKGROUND

Pluripotent stem cells (embryonic stem/induced pluripotent stem cells) have been widely studied as a potential cell source for cell transplantation therapy of Parkinson's disease. However, some difficulties remain to be overcome. These include the need to prepare a large number of dopamine (DA) neurons for clinical use and to culture the cells for a long period to allow their functional maturation and the removal of undifferentiated cells.

METHODS

In this study, aggregates of DA neuron precursors were enclosed in alginate-Ca(2+) microbeads, and the encapsulated aggregates were cultured for 25days to induce cell maturation.

RESULTS

More than 60% of cells in the aggregates differentiated into tyrosine hydroxylase-positive DA neurons. The aggregates could release DA at the same level as aggregates maintained on culture dishes without encapsulation. In addition, by exposure to a citrate solution, the alginate-Ca(2+) gel layer could be easily removed from aggregates without damaging the DA neurons. When the aggregates were transplanted into rat brain, viable cells were found in the graft at one week post-transplantation, with cells extending neurites into the host tissue.

CONCLUSIONS

Cell aggregates encapsulated in alginate-Ca(2+) beads successfully differentiated into mature DA neurons.

GENERAL SIGNIFICANCE

The alginate-Ca(2+) microbead is suitable for maintaining DA precursor aggregates for a long period to allow their functional maturation.