Viability and Functionality of Bovine Chromaffin Cells Encapsulated into Alginate-PLL Microcapsules with a Liquefied Inner Core

In Vitro Exposure of Cultured Porcine Choroid Plexus Epithelial Cells to Immunosuppressant, Anti-Inflammatory, and Psychoactive Drugs

Delivery of neurotrophic molecules to the CNS is a potential treatment for preventing the neuronal loss in neurological disorders such as Huntington's disease (HD). Choroid plexus (CP) epithelial cell transplants secrete several neurotrophic factors and are neuroprotective in rat and monkey animal models of HD. HD patients receiving CP transplants would likely receive a course of immunosuppressant/anti-inflammatory treatment postsurgery and would remain on psychoactive medications to treat their motor, psychiatric, and emotional symptoms. Therefore, we examined whether CP epithelial cells are impacted by incubation with cyclosporine A (CsA), dexmethasone, haloperidol, fluoxetine, and carbamezapine. In each case, DNA was quantified to determine cell number, a formazen dye-based assay was used to quantify cell metabolism, and vascular endothelial growth factor (VEGF) levels were measured as a marker of protein secretion. Except for the highest dose of fluoxetine, none of the drugs tested exerted any detrimental effect on cell number. Incubation with CsA or dexamethasone did not have any consistent significant effect on VEGF secretion or cell metabolism. Carbamazepine was without effect while only the highest dose of haloperidol tested modestly lowered cell metabolism. VEGF secretion and cell metabolism was not measurable from CP cells exposed to 100 μM fluoxetine. These data continue to support the potential use of CP transplants in HD.

Alginate-lanthanide microspheres for MRI-guided embolotherapy

In cancer therapy, a promising treatment option to accomplish a high tumor-to-normal-tissue ratio is endovascular intervention with microsized particles, such as embolotherapy. In this study, alginate microspheres (ams) were prepared with the JetCutter technique, which is based on cutting a sodium alginate solution jet stream into small droplets of uniform size which are then cross-linked with different lanthanides or iron-III, resulting in microspheres of a predefined size which can be visualized by magnetic resonance imaging (MRI). The microspheres were investigated for their size and morphology (light microscopy and scanning electron microscopy analysis), cation content and MRI properties. The lanthanide-ams formulations, with a uniform size of 250 μm and a cation content between 0.72-0.94%, showed promising results for MR imaging. This was further demonstrated for Ho(3+)-cross-linked alginate microspheres (Ho(3+)-ams), the most potent microsphere formulation with respect to MR visualization, allowing single sphere detection and detailed microsphere distribution examination. Intravascular infusion of Ho(3+)-ams by catherization of ex vivo rabbit and porcine liver tissue and assessment of the procedure with MRI clearly showed accumulation and subsequently embolization of the targeted vessels, allowing accurate monitoring of the microsphere biodistribution throughout the tissue. Therefore, the different alginate-lanthanide microsphere formulations developed in this study show great potential for utilization as image-guided embolotherapy agents.

Alginate scaffolds for mesenchymal stem cell cardiac therapy: influence of alginate composition

Despite the success of alginate scaffolds and mesenchymal stem cells (MSCs) therapy in cardiac failure treatment, the impact of the physicochemical environment provided by alginate matrices on cell behavior has never been investigated. The purpose of this work was double: to determine the alginate composition influence on (1) encapsulated rat MSC viability, paracrine activity, and phenotype in vitro and (2) cardiac implantability and in vivo biocompatibility of patch shape scaffolds. Two alginates, differing in composition and thus presenting different mechanical properties when hydrogels, were characterized. In both cases, encapsulated MSC viability was maintained at around 75%, and their secretion characteristics were retained 28 days postencapsulation. In vivo study revealed a high cardiac compatibility of the tested alginates: cardiac parameters were maintained, and rats did not present any sign of infection. Moreover, explanted hydrogels appeared surrounded by a vascularized tissue. However, scaffold implantability was highly dependent on alginate composition. G-type alginate patches, presenting higher elastic and Young moduli than M-type alginate patches, showed a better implantation easiness and were the only ones that maintained their shape and morphology in vivo. As a consequence of alginate chemical composition and resulting hydrogel structuration, G-type alginate hydrogels appear to be more adapted for cardiac implantation.

Review of the history and current status of cell-transplant approaches for the management of neuropathic pain

Treatment of sensory neuropathies, whether inherited or caused by trauma, the progress of diabetes, or other disease states, are among the most difficult problems in modern clinical practice. Cell therapy to release antinociceptive agents near the injured spinal cord would be the logical next step in the development of treatment modalities. But few clinical trials, especially for chronic pain, have tested the transplant of cells or a cell line to treat human disease. The history of the research and development of useful cell-transplant-based approaches offers an understanding of the advantages and problems associated with these technologies, but as an adjuvant or replacement for current pharmacological treatments, cell therapy is a likely near future clinical tool for improved health care.

Evaluation of alginate microspheres for mesenchymal stem cell engraftment on solid organ

Mesenchymal stem cells (MSCs) may be used as a cell source for cell therapy of solid organs due to their differentiation potential and paracrine effect. Nevertheless, optimization of MSC-based therapy needs to develop alternative strategies to improve cell administration and efficiency. One option is the use of alginate microencapsulation, which presents an excellent biocompatibility and an in vivo stability. As MSCs are hypoimmunogenic, it was conceivable to produce microparticles with [alginate-poly-L-lysine-alginate (APA) microcapsules] or without (alginate microspheres) a surrounding protective membrane. Therefore, the aim of this study was to determine the most suitable microparticles to encapsulate MSCs for engraftment on solid organ. First, we compared the two types of microparticles with 4 × 10(6) MSCs/ml of alginate. Results showed that each microparticle has distinct morphology and mechanical resistance but both remained stable over time. However, as MSCs exhibited a better viability in microspheres than in microcapsules, the study was pursued with microspheres. We demonstrated that viable MSCs were still able to produce the paracrine factor bFGF and did not present any chondrogenic or osteogenic differentiation, processes sometimes reported with the use of polymers. We then proved that microspheres could be implanted under the renal capsule without degradation with time or inducing impairment of renal function. In conclusion, these microspheres behave as an implantable scaffold whose biological and functional properties could be adapted to fit with clinical applications.

Human mesenchymal stem cells: Influence of oxygen pressure on proliferation and chondrogenic differentiation in fibrin glue in vitro

Tissue engineering using biomaterials is a promising solution for cartilage replacement. The purpose of this study was to investigate whether the fibrin sealant Tissucol(R) provides a suitable scaffold for re-implanting stem cells during chondrogenic replacement therapy. Pluripotent stem cells were isolated from adult human bone marrow (hMSCs), cultured and characterized by FACS (CD105+/CD106+, CD45-/CD14-/CD34-). A large-holed porous hMSC-containing fibrin matrix was built that allowed hMSCs to survive throughout the period of culture (42 days) in either proliferation or chondrogenic differentiation medium under normoxic (21% O2) or hypoxic (3% O2) conditions. Morphology (as determined by electron microscopy) and proliferation (Ki67 staining) of the embedded hMSCs did not markedly vary under normoxic and hypoxic culture even after 42 days in culture. The stem cell marker Oct-4 was expressed during the whole culture period. Under chondrogenic differentiation conditions, especially under hypoxic conditions, we observed rounded chondrocyte-like cell types and a chondral phenotype assessed by mRNA expression of collagen II and Alcian blue staining. hMSCs seeded into large-holed porous preparations of Tissucol survive, proliferate and keep their stem cell character. Furthermore, culturing the cells in a corresponding medium induces chondrogenic differentiation, which could be remarkably and significantly enhanced under hypoxic conditions.

Cardiac cell generation from encapsulated embryonic stem cells in static and scalable culture systems

Heart diseases are major causes of morbidity and mortality linked to extensive loss of cardiac cells. Embryonic stem cells (ESCs) give rise to cardiomyocyte-like cells, which may be used in heart cell replacement therapies. Most cardiogenic differentiation protocols involve the culture of ESCs as embryoid bodies (EBs). Stirred-suspension bioreactor cultures of ESC aggregates may be employed for scaling up the production of cardiomyocyte progeny but the wide range of EB sizes and the unknown effects of the hydrodynamic environment on differentiating EBs are some of the major challenges in tightly controlling the differentiation outcome. Here, we explored the cardiogenic potential of mouse ESCs (mESCs) and human ESCs (hESCs) encapsulated in poly-L-lysine (pLL)-coated alginate capsules. Liquefaction of the capsule core led to the formation of single ESC aggregates within each bead and their average size depended on the concentration of seeded ESCs. Encapsulated mESCs were directed along cardiomyogenic lineages in dishes under serum-free conditions with the addition of bone morphogenetic protein 4 (BMP4). Human ESCs in pLL-layered liquid core (LC) alginate beads were also differentiated towards heart cells in serum-containing media. Besides the robust cell proliferation, higher fractions of cells expressing cardiac markers were detected in ESCs encapsulated in LC than in solid beads. Furthermore, we demonstrated for the first time that ESCs encapsulated in pLL-layered LC alginate beads can be coaxed towards heart cells in stirred-suspension bioreactors. Encapsulated ESCs yielded higher fractions of Nkx2.5- and GATA4-positive cells in the bioreactor compared to dish cultures. Differentiated cells formed beating foci that responded to chronotropic agents in an organotypic manner. Our findings warrant further development and implementation of microencapsulation technologies in conjunction with bioreactor cultivation to enable the production of stem cell-derived cardiac cells appropriate for clinical therapies and applications.

Cell therapy for pain

BACKGROUND

Management of chronic pain remains a challenge in spite of numerous drugs that are either approved or still in development. Apart from inadequate relief, there are concerns about adverse effects and addiction. Cell therapy is being explored for relief of pain.

OBJECTIVE

To address the rationale for cell therapy for treatment of pain and its advantages over conventional pharmaceuticals. The prospects of translation of these techniques from experimental animals to clinical use are discussed.

METHODS

This review is based on the literature on cell therapy in relation to pain and is confined to experimental work as there are no approved therapies in this category.

RESULTS/CONCLUSIONS

A number of promising cell therapy technologies have been identified. These provide targeted approaches to delivery of antinociceptive molecules, avoiding subjecting the patient to systemic toxicity of drugs. There has been considerable progress in treating degenerative joint diseases causing pain. Management of neuropathic pain is a challenge and a number of ongoing studies are addressing it. Overall the future of cell therapy for pain is promising.

A novel injectable scaffold for cartilage tissue engineering using adipose-derived adult stem cells

Articular cartilage has a limited self-regenerative capacity. Thus, treatment of cartilage lesions is a major challenge. Tissue engineering using a variety of biomaterials is a promising solution to the problem of cartilage damage. In this in vitro study, we investigated the effect of the presence of cartilage-tissue chondroitin-sulfate (CS) in a fibrin scaffold on the differentiation of adipose-derived adult stem cells (ADAS cells) into chondrocytes. Isolated rabbit ADAS cells were cultured in fibrin matrices with and without CS for up to 14 days. ADAS cells differentiated into chondrocytes in both matrices, but cell proliferation, glycoaminoglycans content, and type II collagen expression were significantly higher in the fibrin-CS matrices than those in the fibrin matrices alone. Histological examination and scanning electronic microscopy revealed the fibrin-CS matrices exceeded in inducing differentiation of ADAS cells into chondrocytes in terms of tissue morphological characteristics. We concluded that the fibrin-CS matrices mimicking native cartilage extracellular matrix could act as a three-dimensional scaffold for cartilage tissue engineering and have the potential for promoting ADAS cells differentiation into chondrocytes.

In vitro evaluation of alginate encapsulated adipose-tissue stromal cells for use as injectable bone graft substitute

This study aims to investigate the survival and osteogenic behavior of murine-derived adipose-tissue stromal cells (ATSCs) encapsulated in alginate microcapsules thereby instigating further studies in this cell delivery strategy for in vivo osteogenesis. Cell viability was quantified using a tetrazolium-based assay and osteogenic differentiation was evaluated by both alkaline-phosphatase (ALP) histochemistry and osteocalcin mRNA analysis. Following microencapsulation, cell numbers increased from 3.9 x 10(3) on day 1 to 7.8 x 10(3) on day 7 and maintained excellent viability in the course of 21-day culture. ALP was 6.9, 5.5, and 3.2 times higher than monolayer cultures on days 7, 14, and 21, respectively. In addition, osteocalcin mRNA was detectable in encapsulated cultures earlier (day 14) than monolayer cultures. We conclude that alginate microcapsules can act as three-dimensional matrix for ATSC proliferation and has potential for use as injectable, biodegradable scaffold in bone tissue engineering.