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Introduction: Nestin-expressing cells isolated from different human tissues reveal self-renewal capacity and a multilineage differentiation potential. In particular, adult stem/progenitor cell populations from exocrine glands such as the pancreas, salivary gland and sweat gland are characterized by prominent nestin expression. Interestingly, human mammary gland histological examinations also demonstrated the existence of nestin-positive cells in the ductal compartments. Within the scope of our previous work we wonder whether an isolation of nestin-positive cell populations from human mammary gland biopsies is possible and what characteristics they have in vitro. Cell populations from both sexes were propagated and subjected to a comparison with other gland-derived cell populations., Methods: Human mammary tissue biopsies were mechanically and enzymatically treated, and the isolated acini structures were observed with time-lapse microscopy to track adherently outgrowing cells. The proliferation potential of the cell population was assessed by performing growth curves. On the gene and protein levels we investigated the expression of stem cell markers as well as markers indicating multilineage differentiation., Results: We succeeded in establishing proliferating cell populations from breast tissue biopsies of both sexes. Our results display several similarities to the glandular stem cell populations from other exocrine glands. Beside their proliferation capacity during in vitro culture, the obtained cell populations are characterized by their prominent nestin expression. The cells share surface proteins commonly expressed on adult stem cells. We demonstrated the expression of stem cell-related genes like Oct4, Sox2, KLF4 and Nanog, and confirmed multipotent differentiation capacity by detecting transcripts expressed in endodermal, mesodermal and ectodermal cell types., Conclusion: With this study we present an efficient procedure for isolation and propagation of nestin-positive stem cells obtained from male and female breast tissue, which is frequently available. The established multipotent cell populations could be easily expanded in vitro and thus hold promise for cell-based therapies and personalized medicine.

Some cancers have a poor prognosis and often lead to local recurrence because they are resistant to available treatments, e.g., glioblastoma. Attempts have been made to increase the sensitivity of resistant tumors by targeting pathways involved in the resistance and combining it, for example, with radiotherapy (RT). We have previously reported that treating glioblastoma stem cells with an Nrf2 inhibitor increases their radiosensitivity. Unfortunately, the application of drugs can also affect normal cells. In the present study, we aim to investigate the role of the Nrf2 pathway in the survival and differentiation of normal human adipose-derived stem cells (ADSCs) exposed to radiation. We treated ADSCs with an Nrf2 inhibitor and then exposed them to X-rays, protons or carbon ions. All three radiation qualities are used to treat cancer. The survival and differentiation abilities of the surviving ADSCs were studied. We found that the enhancing effect of Nrf2 inhibition on cell survival levels was radiation-quality-dependent (X-rays > proton > carbon ions). Furthermore, our results indicate that Nrf2 inhibition reduces stem cell differentiation by 35% and 28% for adipogenesis and osteogenesis, respectively, using all applied radiation qualities. Interestingly, the results show that the cells that survive proton and carbon ion irradiations have an increased ability, compared with X-rays, to differentiate into osteogenesis and adipogenesis lineages. Therefore, we can conclude that the use of carbon ions or protons can affect the stemness of irradiated ADSCs at lower levels than X-rays and is thus more beneficial for long-time cancer survivors, such as pediatric patients. [ABSTRACT FROM AUTHOR]

Background: Nerve guide conduits are a promising strategy for reconstructing peripheral nerve defects. Improving the survival rate of seed cells in nerve conduits is still a challenge and microcarriers are an excellent three-dimensional (3D) culture scaffold. Here, we investigate the effect of the 3D culture of microcarriers on the biological characteristics of adipose mesenchymal stem cells (ADSCs) and to evaluate the efficacy of chitosan nerve conduits filled with microcarriers loaded with ADSCs in repairing nerve defects. Methods: In vitro, we prepared porous chitosan microspheres by a modified emulsion cross-linking method for loading ADSCs and evaluated the growth status and function of ADSCs. In vivo, ADSCs-loaded microcarriers were injected into chitosan nerve conduits to repair a 12 mm sciatic nerve defect in rats. Results: Compared to the conventional two-dimensional (2D) culture, the prepared microcarriers were more conducive to the proliferation, migration, and secretion of trophic factors of ADSCs. In addition, gait analysis, neuro-electrophysiology, and histological evaluation of nerves and muscles showed that the ADSC microcarrier-loaded nerve conduits were more effective in improving nerve regeneration. Conclusions: The ADSCs-loaded chitosan porous microcarrier prepared in this study has a high cell engraftment rate and good potential for peripheral nerve repair. [ABSTRACT FROM AUTHOR]

Cell-therapy-based nerve repair strategies hold great promise. In the field, there is an extensive amount of evidence for better regenerative outcomes when using tissue-engineered nerve grafts for bridging severe gap injuries. Although a massive number of studies have been performed using rodents, only a limited number involving nerve injury models of large animals were reported. Nerve injury models mirroring the human nerve size and injury complexity are crucial to direct the further clinical development of advanced therapeutic interventions. Thus, there is a great need for the advancement of research using large animals, which will closely reflect human nerve repair outcomes. Within this context, this review highlights various stem cell-based nerve repair strategies involving large animal models such as pigs, rabbits, dogs, and monkeys, with an emphasis on the limitations and strengths of therapeutic strategy and outcome measurements. Finally, future directions in the field of nerve repair are discussed. Thus, the present review provides valuable knowledge, as well as the current state of information and insights into nerve repair strategies using cell therapies in large animals. [ABSTRACT FROM AUTHOR]

Diabetic neuropathy (DN) is one of the most frequent and troublesome complications of diabetes mellitus. Evidence from diabetic animal models and diabetic patients suggests that reduced availability of neuroprotective and pro-angiogenic factors in the nerves in combination with a chronic pro-inflammatory microenvironment and high level of oxidative stress, contribute to the pathogenesis of DN. Mesenchymal stem cells (MSCs) are of great interest as therapeutic agents for regenerative purposes, since they can secrete a broad range of cytoprotective and anti-inflammatory factors. Therefore, the use of the MSC secretome may represent a promising approach for DN treatment. Recent data indicate that the paracrine potential of MSCs could be boosted by preconditioning these cells with an environmental or pharmacological stimulus, enhancing their therapeutic efficacy. In the present study, we observed that the preconditioning of human adipose tissue-derived MSCs (AD-MSCs) with 150μM or 400μM of the iron chelator deferoxamine (DFX) for 48 hours, increased the abundance of the hypoxia inducible factor 1 alpha (HIF-1α) in a concentration dependent manner, without affecting MSC morphology and survival. Activation of HIF-1α led to the up-regulation of the mRNA levels of pro-angiogenic factors like vascular endothelial growth factor alpha and angiopoietin 1. Furthermore this preconditioning increased the expression of potent neuroprotective factors, including nerve growth factor, glial cell-derived neurotrophic factor and neurotrophin-3, and cytokines with anti-inflammatory activity like IL4 and IL5. Additionally, we observed that these molecules, which could also be used as therapeutics, were also increased in the secretome of MSCs preconditioned with DFX compared to the secretome obtained from non-preconditioned cells. Moreover, DFX preconditioning significantly increased the total antioxidant capacity of the MSC secretome and they showed neuroprotective effects when evaluated in an in vitro model of DN. Altogether, our findings suggest that DFX preconditioning of AD-MSCs improves their therapeutic potential and should be considered as a potential strategy for the generation of new alternatives for DN treatment. [ABSTRACT FROM AUTHOR]

As a promising alternative to autologous nerve grafts, tissue-engineered nerve grafts have been extensively studied as a way to bridge peripheral nerve defects and guide nerve regeneration. The main difference between autogenous nerve grafts and tissue-engineered nerve grafts is the regenerative microenvironment formed by the grafts. If an appropriate regenerative microenvironment is provided, the repair of a peripheral nerve is feasible. In this study, to mimic the body’s natural regenerative microenvironment closely, we co-cultured Schwann cells (SCs) and adipose-derived stem cells (ADSCs) as seed cells and introduced them into a silk fibroin (SF)/collagen scaffold to construct a tissue-engineered nerve conduit (TENC). Twelve weeks after the three different grafts (plain SF/collagen scaffold, TENC, and autograft) were transplanted to bridge 1-cm long sciatic nerve defects in rats, a series of electrophysiological examinations and morphological analyses were performed to evaluate the effect of the tissue-engineered nerve grafts on peripheral nerve regeneration. The regenerative outcomes showed that the effect of treatment with TENCs was similar to that with autologous nerve grafts but superior to that with plain SF/collagen scaffolds. Meanwhile, no experimental animals had inflammation around the grafts. Based on this evidence, our findings suggest that the TENC we developed could improve the regenerative microenvironment and accelerate nerve regeneration compared to plain SF/collagen and may serve as a promising strategy for peripheral nerve repair. [ABSTRACT FROM AUTHOR]

Background/Aims: The treatment of peripheral nerve lesions still represents a clinical challenge. Several approaches such as novel biomaterials for nerve guides, addition of growth factors or cellular supplements moved in the focus of research. Especially the application of autologous stem cells is highly promising for future applications. Human sweat gland derived stem cells (hSGSCs) represent an easy accessible source of autologous adult stem cells and did already show a beneficial effect in dermal wound healing. Methods: In this study, the effect of hSGSCs on neurite outgrowth of primary adult or prenatal Dorsal root ganglia (DRG) neurons was analysed in an indirect co-culture model. Additionally, direct co-cultures with hSGSCs as a feeder layer were performed. Results: Adult and prenatal DRG neurons showed increased neurite outgrowth after 24 h co-culture with hSGSCs. The outgrowth increased significantly by the factors 5.6 and 2.6 respectively. Direct co-cultures revealed neurite alignment along the hSGSCs orientation. Conclusion: The paracrine influence of hSGSCs on neurite outgrowth, but also their ability to operate as a feeder layer with guidance properties shows great potential for future applications in peripheral nerve regeneration. © 2014 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Objective(s) Bone marrow is the traditional source of human multipotent mesenchymal stem cells (MSCs), but adipose tissue appears to be an alternative and more readily available source. In this study, rat adipose-derived stem cells (ADSCs) were induced to differentiate into Schwann-like cells and compared with rat bone marrow stem cells (BMSCs) for their Schwann-like cells differentiation potential. Materials and Methods BMSCs and ADSCs were characterized for expression of MSCs-specific markers, osteogenic and adipogenic differentiation. They were induced to differentiate into Schwann-like cells and analyzed for expression of the Schwann specific markers. The immunocytochemical differentiation markers were S-100 and real time quantitative Real-time polymerase chain reaction (RT-PCR) markers were S100, P75 and glial fibrillary acidic protein (GFAP). 3-(4, 5-Dimethylthiazol- 2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and Annexin V-Fluorescein isothiocyanate (FITC)/ Propidium iodide (PI) double labeling method were employed to detect early stage cell apoptosis. Results BMSCs and ADSCs showed similarities in expression of the MSC-specific markers, osteogenic and adipogenic differentiation. Both quantitative RT-PCR and immunocytochemical analysis demonstrated that BMSCs and ADSCs had equal expression of the Schwann-specific markers following Schwann-like cells differentiation. However, gene expression of P75 was higher in BMSCs compared with ADSCs. MTT assay and flow cytometry found that of the total BMSCs and ADSCs in the culture medium, 20% to 30% of the cells died, but the remaining cell population remained strongly attached to the substrate and differentiated. Conclusion Comparative analysis showed that Schwann-like cell differentiation potential of ADSCs was slightly decreased in comparison with BMSCs. Therefore, BMSCs are more favorable choice than ADSCs for tissue engineering. [ABSTRACT FROM AUTHOR]

Adult stem cells have therapeutic potential because of their intrinsic capacity for self-renewal, especially for bone regeneration. The present study shows the utility of ex vivo modified mesenchymal stem cells (MSC) to enhance bone density in an immunocompetent mouse model of osteopenia. MSC were transduced ex vivo with a recombinant adeno-associated virus 2 (rAAV2) expressing bone morphogenetic protein 2 (BMP2) under the transcriptional control of collagen type-1α promoter. To enrich bone homing in vivo, we further modified the cells to transiently express the mouse α4 integrin. The modified MSC were systemically administered to ovariectomized, female C57BL/6 mice. Effects of the therapy were determined by dual-energy X-ray absorptiometry, 3D micro-CT, histology and immunohistochemistry for up to 6 months. Results indicated that mice transplanted with MSC expressing BMP2 showed significant increase in bone mineral density and bone mineral content (P<0.001) with relatively better proliferative capabilities of bone marrow stromal cells and higher osteocompetent pool of cells compared to control animals. Micro-CT analysis of femora and other bone histomorphometric analyses indicated more trabecular bone following MSC-BMP2 therapy. Results obtained by transplanting genetically modified MSC from green fluorescent protein transgenic mouse suggested that production of BMP2 from transplanted MSC also influenced the mobilization of endogenous progenitors for new bone formation. [ABSTRACT FROM AUTHOR]

OBJECTIVE--Mesenchymal stem cells (MSCs) have been reported to secrete various cytokines that exhibit angiogenic and neurosupportive effects. This study was conducted to investigate the effects of MSC transplantation on diabetic polyneuropathy (DPN) in rats. RESEARCH DESIGN AND METHODS--MSCs were isolated from bone marrow of adult rats and transplanted into hind limb skeletal muscles of rats with an 8-week duration of streptozotocin (STZ)-induced diabetes or age-matched normal rats by unilateral intramuscular injection. Four weeks after transplantation, vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) productions in transplanted sites, current perception threshold, nerve conduction velocity (NCV), sciatic nerve blood flow (SNBF), capillary number--to--muscle fiber ratio in soleus muscles, and sural nerve morphometry were evaluated. RESULTS--VEGF and bFGF mRNA expression were significantly increased in MSC-injected thigh muscles of STZ-induced diabetic rats. Furthermore, colocalization of MSCs with VEGF and bFGF in the transplanted sites was confirmed. STZ-induced diabetic rats showed hypoalgesia, delayed NCV, decreased SNBF, and decreased capillary number--to--muscle fiber ratio in soleus muscles, which were all ameliorated by MSC transplantation. Sural nerve morphometry showed decreased axonal circularity in STZ-induced diabetic rats, which was normalized by MSC transplantation. CONCLUSIONS--These results suggest that MSC transplantation could have therapeutic effects on DPN through paracrine actions of growth factors secreted by MSCs. Diabetes 57: 3099-3107, 2008 [ABSTRACT FROM AUTHOR]

Background: Schwann cells (SC) which are myelin-forming cells in peripheral nervous system are very useful for the treatment of diseases of peripheral nervous system and central nervous system. However, it is difficult to obtain sufficient large number of SC for clinical use, so alternative cell systems are desired. Results: Using a procedure similar to the one used for propagation of neural stem cells, we could induce rat adipose-derived stem cells (ADSC) into floating neurospheres. In addition to being able to differentiate into neuronal- and glial-like cells, neurospheres could be induced to differentiate into SC-like cells. SC-like cells were bi- or tri-polar in shape and immunopositive for nestin and SC markers p75, GFAP and S-100, identical to genuine SC. We also found that SC-like cells could induce the differentiation of SH-SY5Y neuroblastoma cells efficiently, perhaps through secretion of soluble substances. We showed further that SC-like cells could form myelin structures with PC12 cell neurites in vitro. Conclusion: These findings indicated that ADSC could differentiate into SC-like cells in terms of morphology, phenotype and functional capacities. SC-like cells induced from ADSC may be useful for the treatment of neurological diseases. [ABSTRACT FROM AUTHOR]

The sensory nerve is highly involved in lower extremity wound healing. In diabetic and vascular diseases, impaired nerve function and blood flow delay wound healing. Tissue regeneration using adult stem cells is a targeted therapeutic modality in disorders of nerve and blood supply. Effective delivery using an autologous vascularized fascial flap as a vehicle of stem cells leads to severed sensory nerve recovery, local tissue blood flow, and wound healing. Human MSCs (hMSCs) were transfected with green fluorescent protein (GFP) cDNA and tested for efficiency and proliferation in vitro. The nude rat model with femoral vessel and saphenous nerve severance and ligation was wrapped with a vascularized epigastric flap for GFP-hMSC, fibroblast growth factor-2 (FGF-2), or a combination of both after 2 weeks. Maximum nerve conduction velocity recovered to 70% of the presurgical level in the GFP-hMSC- and FGF-2-treated group at 2 weeks. Blood flow and nerve conduction velocity were positively correlated at 1 week. Wound healing in the ipsilateral paw had significantly improved by 1 week. Histologically, blood vessels and nerves are very organized, and regenerated neuron immunoreactivity of GAP-43 and a nerve regrowth marker of S-100 were remarkable in the human GFP (hGFP)-hMSC and FGF-2-treated group at 2 weeks; therefore, sensory nerve regeneration, blood flow, and wound healing were improved by the administration of stem cells and FGF-2 via a vascularized flap. This may be implicated in clinical denervated and reduced circulation tissue wound healing. [ABSTRACT FROM AUTHOR]

Ionising radiation-induced normal tissue damage is a major concern in clinic and public health. It is the most limiting factor in radiotherapy treatment of malignant diseases. It can also cause a serious harm to populations exposed to accidental radiation exposure or nuclear warfare. With regard to the clinical use of radiation, there has been a number of modalities used in the field of radiotherapy. These includes physical modalities such modified collimators or fractionation schedules in radiotherapy. In addition, there are a number of pharmacological agents such as essential fatty acids, vasoactive drugs, enzyme inhibitors, antioxidants, and growth factors for the prevention or treatment of radiation lesions in general. However, at present, there is no standard procedure for the treatment of radiation-induced normal tissue lesions. Stem cells and their role in tissue regeneration have been known to biologists, in particular to radiobiologists, for many years. It was only recently that the potential of stem cells was studied in the treatment of radiation lesions. Stem cells, immediately after their successful isolation from a variety of animal and human tissues, demonstrated their likely application in the treatment of various diseases. This paper describes the types and origin of stem cells, their characteristics, current research, and reviews their potential in the treatment and regeneration of radiation induced normal tissue lesions. Adult stem cells, among those mesenchymal stem cells (MSCs), are the most extensively studied of stem cells. This review focuses on the effects of MSCs in the treatment of radiation lesions. [ABSTRACT FROM AUTHOR]

(1) Background: Emerging interest of physicians to use adipose-derived stem cells (ADSCs) for regenerative therapies and the fact that low-dose irradiation (LD-IR ≤ 0.1 Gy) has been reported to enhance the proliferation of several human normal and bone-marrow stem cells, but not that of tumor cells, lead to the idea of improving stem cell therapies via low-dose radiation. Therefore, the aim of this study was to investigate unwanted side effects, as well as proliferation-stimulating mechanisms of LD-IR on ADSCs. (2) Methods: To avoid donor specific effects, ADSCs isolated from mamma reductions of 10 donors were pooled and used for the radiobiological analysis. The clonogenic survival assay was used to classify the long-term effects of low-dose radiation in ADSCs. Afterwards, cytotoxicity and genotoxicity, as well as the effect of irradiation on proliferation of ADSCs were investigated. (3) Results: LD (≤ 0.1 Gy) of ionizing radiation promoted the proliferation and survival of ADSCs. Within this dose range neither geno- nor cytotoxic effects were detectable. In contrast, greater doses within the dose range of >0.1–2.0 Gy induced residual double-strand breaks and reduced the long-term survival, as well as the proliferation rate of ADSCs. (4) Conclusions: Our data suggest that ADSCs are resistant to LD-IR. Furthermore, LD-IR could be a possible mediator to improve approaches of stem cells in the field of regenerative medicine. [ABSTRACT FROM AUTHOR]