Ensheathing cell-conditioned medium directs the differentiation of human umbilical cord blood cells into aldynoglial phenotype cells

Despite their similarities to bone marrow precursor cells (PC), human umbilical cord blood (HUCB) PCs are more immature and, thus, they exhibit greater plasticity. This plasticity is evident by their ability to proliferate and spontaneously differentiate into almost any cell type, depending on their environment. Moreover, HUCB-PCs yield an accessible cell population that can be grown in culture and differentiated into glial, neuronal and other cell phenotypes. HUCB-PCs offer many potential therapeutic benefits, particularly in the area of neural replacement. We sought to induce the differentiation of HUCB-PCs into glial cells, known as aldynoglia. These cells can promote neuronal regeneration after lesion and they can be transplanted into areas affected by several pathologies, which represents an important therapeutic strategy to treat central nervous system damage. To induce differentiation to the aldynoglia phenotype, HUCB-PCs were exposed to different culture media. Mononuclear cells from HUCB were isolated and purified by identification of CD34 and CD133 antigens, and after 12 days in culture, differentiation of CD34+ HUCB-PCs to an aldynoglia phenotypic, but not that of CD133+ cells, was induced in ensheathing cell (EC)-conditioned medium. Thus, we demonstrate that the differentiation of HUCB-PCs into aldynoglia cells in EC-conditioned medium can provide a new source of aldynoglial cells for use in transplants to treat injuries or neurodegenerative diseases.

The bed and the bugs: interactions between the tumor microenvironment and cancer stem cells

Tumors have been increasingly recognized as organs with a complexity that approaches, and may even exceed, that of healthy tissues. When viewed from this perspective, the biology of a tumor can be understood only by studying tumor cell heterogeneity and the microenvironment that is constructed during the course of tumorigenesis and malignant progression. Recent work has revealed the existence of cancer stem cells, the "bugs", with the capacity for self-renewal and tumor propagation. In addition, it is now recognized that the tumor microenvironment, the "bed", plays a critical role in supporting cancer stem cells and also may promote neoplasia and malignant progression. The interdependence of the cell-intrinsic features of cancer, including the cancer stem cell "bugs" and the tumor microenvironment "bed", is only beginning to be understood. In this review, we highlight the rapidly evolving concepts about the interactions between tumor stem cells and their microenvironment, the insights gained from studying their normal tissue counterparts, and the questions and controversies surrounding this area of research, with an emphasis on breast and lung cancer. Finally, we address evidence supporting the notion that eliminating the bed as well as the bugs should lead to more effective and personalized cancer treatments that improve patient outcome.

Adipose tissue cells, lipotransfer and cancer: a challenge for scientists, oncologists and surgeons

Despite recent evidence of the cancer-promoting role of adipose tissue-derived progenitor and differentiated cells, the use of lipotransfer for tissue/organ reconstruction after surgical removal of cancer is increasing worldwide. Here we discuss in a multidisciplinary fashion the preclinical data connecting obesity, adipose cells and cancer progression, as well as the clinical data concerning safety of lipotransfer procedures in cancer patients. A roadmap towards a more rationale use of lipotransfer in oncology is urgently needed and should include preclinical studies to dissect the roles of different adipose tissue-derived cells, the evaluation of drugs currently candidate to inhibit the interaction between adipose and tumor cells, and carefully designed clinical trials to investigate the safety of lipotransfer procedures in cancer patients.

Human neural crest stem cells derived from human ESCs and induced pluripotent stem cells: induction, maintenance, and differentiation into functional schwann cells

The neural crest (NC) is a transient, multipotent, migratory cell population unique to vertebrates that gives rise to diverse cell lineages. Much of our knowledge of NC development comes from studies of organisms such as chicken and zebrafish because human NC is difficult to obtain because of its transient nature and the limited availability of human fetal cells. Here we examined the process of NC induction from human pluripotent stem cells, including human embryonic stem cells (hESCs) and induced pluripotent stem cells (iPSCs). We showed that NC cells could be efficiently induced from hESCs by a combination of growth factors in medium conditioned on stromal cells and that NC stem cells (NCSCs) could be purified by p75 using fluorescence-activated cell sorting (FACS). FACS-isolated NCSCs could be propagated in vitro in five passages and cryopreserved while maintaining NCSC identity characterized by the expression of a panel of NC markers such as p75, Sox9, Sox10, CD44, and HNK1. In vitro-expanded NCSCs were able to differentiate into neurons and glia (Schwann cells) of the peripheral nervous system, as well as mesenchymal derivatives. hESC-derived NCSCs appeared to behave similarly to endogenous embryonic NC cells when injected in chicken embryos. Using a defined medium, we were able to generate and propagate a nearly pure population of Schwann cells that uniformly expressed glial fibrillary acidic protein, S100, and p75. Schwann cells generated by our protocol myelinated rat dorsal root ganglia neurons in vitro. To our knowledge, this is the first report on myelination by hESC- or iPSC-derived Schwann cells.

Defined xenogeneic-free and hypoxic environment provides superior conditions for long-term expansion of human adipose-derived stem cells

Development and implementation of therapeutic protocols based on stem cells or tissue-engineered products relies on methods that enable the production of substantial numbers of cells while complying with stringent quality and safety demands. In the current study, we aimed to assess the benefits of maintaining cultures of adipose-derived stem cells (ASCs) in a defined culture system devoid of xenogeneic components (xeno-free) and hypoxia over a 49-day growth period. Our data provide evidence that conditions involving StemPro mesenchymal stem cells serum-free medium (SFM) Xeno-Free and hypoxia (5% oxygen concentration) in the culture atmosphere provide a superior proliferation rate compared to a standard growth environment comprised of alpha-modified Eagle medium (A-MEM) supplemented with fetal calf serum (FCS) and ambient air (20% oxygen concentration) or that of A-MEM supplemented with FCS and hypoxia. Furthermore, a flow cytometric analysis and in vitro differentiation assays confirmed the immunophenotype stability and maintained multipotency of ASCs when expanded under xeno-free conditions and hypoxia. In conclusion, our data demonstrate that growth conditions utilizing a xeno-free and hypoxic environment not only provide an improved environment for the expansion of ASCs, but also set the stage as a culture system with the potential broad spectrum utility for regenerative medicine and tissue engineering applications.

Cell type-associated differences in migration, survival, and immunogenicity following grafting in CNS tissue

Cell transplantation has been suggested to display several neuroprotective and/or neuroregenerative effects in animal models of central nervous system (CNS) trauma. However, while most studies report on clinical observations, currently little is known regarding the actual fate of the cell populations grafted and whether or how the brain's innate immune system, mainly directed by activated microglia and astrocytes, interacts with autologous cellular implants. In this study, we grafted well-characterized neural stem cell, mouse embryonic fibroblast, dendritic cell, bone marrow mononuclear cell, and splenocyte populations, all isolated or cultured from C57BL/6-eGFP transgenic mice, below the capsula externa (CE) of healthy C57BL/6 mice and below the inflamed/demyelinated CE of cuprizone-treated C57BL/6 mice. Two weeks postgrafting, an extensive quantitative multicolor histological analysis was performed in order (i) to quantify cell graft localization, migration, survival, and toxicity and (ii) to characterize endogenous CNS immune responses against the different cell grafts. Obtained results indicate dependence on the cell type grafted: (i) a different degree of cell graft migration, survival, and toxicity and (ii) a different organization of the endogenous immune response. Based on these observations, we warrant that further research should be undertaken to understand-and eventually control-cell graft-induced tissue damage and activation of the brain's innate immune system. The latter will be inevitable before cell grafting in the CNS can be performed safely and successfully in clinical settings.

Transplantation of umbilical cord-derived mesenchymal stem cells as a novel strategy to protect the central nervous system: technical aspects, preclinical studies, and clinical perspectives

The prevention of perinatal neurological disabilities remains a major challenge for public health, and no neuroprotective treatment to date has proven clinically useful in reducing the lesions leading to these disabilities. Efforts are, therefore, urgently needed to test other neuroprotective strategies including cell therapies. Although stem cells have raised great hopes as an inexhaustible source of therapeutic products that could be used for neuroprotection and neuroregeneration in disorders affecting the brain and spinal cord, certain sources of stem cells are associated with potential ethical issues. The human umbilical cord (hUC) is a rich source of stem and progenitor cells including mesenchymal stem cells (MSCs) derived either from the cord or from cord blood. hUC MSCs (hUC-MSCs) have several advantages as compared to other types and sources of stem cells. In this review, we will summarize the most recent findings regarding the technical aspects and the preclinical investigation of these promising cells in neuroprotection and neuroregeneration, and their potential use in the developing human brain. However, extensive studies are needed to optimize the administration protocol, safety parameters, and potential preinjection cell manipulations before designing a controlled trial in human neonates.

Human umbilical cord is a unique and safe source of various types of stem cells suitable for treatment of hematological diseases and for regenerative medicine

Cord blood (CB) is a rich source of hematopoietic stem cells (HSCs) and for this reason CB transplantation has been used successfully for the treatment of some malignant and nonmalignant diseases. However, this technique is limited by the relatively low number of HSCs present in each CB unit and by the delayed engraftment of platelets and neutrophils. To bypass these obstacles efforts have been made to develop strategies to expand CB HSCs in vitro for transplantation. CB is also an important source of other stem cells, including endothelial progenitors, mesenchymal stem cells (MSCs), very small embryonic/epiblast-like (VSEL) stem cells, and unrestricted somatic stem cells (USSC), potentially suitable for use in regenerative medicine. For some of these stem cell populations, such as MSCs, clinical studies have been started and for other stem cell populations potential clinical applications have been identified and clinical studies will follow. In addition to CB, other parts of umbilical cord, such as the Wharton's jelly, or tissues strictly linked such as the placenta are also rich sources of stem cells.

Stromal vascular fraction isolated from lipo-aspirates using an automated processing system: bench and bed analysis

The heterogeneous stromal vascular fraction (SVF), containing adipose-derived stem/progenitor cells (ASCs), can be easily isolated through enzymatic digestion of aspirated adipose tissue. In clinical settings, however, strict control of technical procedures according to standard operating procedures and validation of cell-processing conditions are required. Therefore, we evaluated the efficiency and reliability of an automated system for SVF isolation from adipose tissue. SVF cells, freshly isolated using the automated procedure, showed comparable number and viability to those from manual isolation. Flow cytometric analysis confirmed an SVF cell composition profile similar to that after manual isolation. In addition, the ASC yield after 1 week in culture was also not significantly different between the two groups. Our clinical study, in which SVF cells isolated with the automated system were transplanted with aspirated fat tissue for soft tissue augmentation/reconstruction in 42 patients, showed satisfactory outcomes with no serious side-effects. Taken together, our results suggested that the automated isolation system is as reliable a method as manual isolation and may also be useful in clinical settings. Automated isolation is expected to enable cell-based clinical trials in small facilities with an aseptic room, without the necessity of a good manufacturing practice-level cell processing area.

From tendon to nerve: an MSC for all seasons

The potential of mesenchymal stem cells (MSCs) to regenerate damaged tissue is well documented, as this specialized progenitor cell type exhibits superior cellular properties, and would allow medical as well as ethical limitations to be overcome. By now, MSCs have been successfully introduced in manifold experimental approaches within the newly defined realm of Regenerative Medicine. Advanced methods for in vitro cell expansion, defined induction of distinct differentiation processes, 3-dimensional culture on specific scaffold material, and tissue engineering approaches have been designed, and many clinical trials not only have been launched, but recently could be completed. To date, most of the MSC-based therapeutic approaches have been executed to address bone, cartilage, or heart regeneration; further, prominent studies have shown the efficacy of ex vivo expanded and infused MSCs to countervail graft-versus-host disease. Yet more fields of application emerge in which MSCs unfold beneficial effects, and presently, therapies that effectively ameliorate nonhealing conditions after tendon or spinal cord injury are, courtesy of scientific research, forging ahead to the clinical trial stage.

Analysis of embryoid bodies derived from human induced pluripotent stem cells as a means to assess pluripotency

Human induced pluripotent stem cells (hiPSCs) have core properties of unlimited self-renewal and differentiation potential and have emerged as exciting cell sources for applications in regenerative medicine, drug discovery, understanding of development, and disease etiology. Key among numerous criteria to assess pluripotency includes the in vivo teratoma assay that has been widely proposed as a standard functional assay to demonstrate the pluripotency of hiPSCs. Yet, the lack of reliability across methodologies, lack of definitive clinical significance, and associated expenses bring into question use of the teratoma assay as the “gold standard” for determining pluripotency. We propose use of the in vitro embryoid body (EB) assay as an important alternative to the teratoma assay. This paper summarizes the methodologies for creating EBs from hiPSCs and the subsequent analyses to assess pluripotency and proposes its use as a cost-effective, controlled, and reproducible approach that can easily be adopted to determine pluripotency of generated hiPSCs.

Genetic modification of human adipose-derived stem cells for promoting wound healing

BACKGROUND

Diverse growth factors secreted from human adipocyte-derived stem cells (hASCs) that support or manage adjacent cells have been studied for therapeutic potentials to a variety of pathological models. However, senescent growth arrest in hASCs during in vitro culture and subsequent defective differentiation potential, have been technical barriers to further genetic modification of hASCs for functional improvement.

OBJECTIVE

We investigated the feasibility of long-term hASC culture to enhance their therapeutic use.

METHODS

We used a MYC variant to generate hASCs expressing v-myc and determined their growth potential and growth factor secretion profile. We further introduced an AKT variant to generate constitutively active (CA)-Akt/v-myc hASCs. Finally, we tested the ability of promoting wound healing of medium conditioned with CA-Akt/v-myc hASCs.

RESULTS

The v-myc hASCs actively proliferated longer than control hASCs. Increased secretion of vascular endothelial growth factor (VEGF) by v-myc hASCs promoted the migration potential of hASCs and vasculogenesis in co-cultured endothelial cells. Additional genetic modification of v-myc hASCs using CA-Akt further increased VEGF secretion. In addition, injection of CA-Akt/v-myc hASCs-CM into wound-mice model promoted wound healing compared to normal hASCs-CM.

CONCLUSION

Genetic modification of hASCs to stimulate secretion of growth factors is a novel strategy to maximize their paracrine effect and improve their therapeutic potential.

Dynamic culture improves MSC adhesion on freeze-dried bone as a scaffold for bone engineering

AIM

To investigate the interaction between mesenchymal stem cells (MSCs) and bone grafts using two different cultivation methods: static and dynamic.

METHODS

MSCs were isolated from rat bone marrow. MSC culture was analyzed according to the morphology, cell differentiation potential, and surface molecular markers. Before cell culture, freeze-dried bone (FDB) was maintained in culture for 3 d in order to verify culture medium pH. MSCs were co-cultured with FDB using two different cultivation methods: static co-culture (two-dimensional) and dynamic co-culture (three-dimensional). After 24 h of cultivation by dynamic or static methods, histological analysis of Cell adhesion on FDB was performed. Cell viability was assessed by the Trypan Blue exclusion method on days 0, 3 and 6 after dynamic or static culture. Adherent cells were detached from FDB surface, stained with Trypan Blue, and quantified to determine whether the cells remained on the graft surface in prolonged non-dynamic culture. Statistical analyses were performed with SPSS and a P < 0.05 was considered significant.

RESULTS

The results showed a clear potential for adipogenic and osteogenic differentiation of MSC cultures. Rat MSCs were positive for CD44, CD90 and CD29 and negative for CD34, CD45 and CD11bc. FDBs were maintained in culture for 3 d and the results showed there was no significant variation in the culture medium pH with FDB compared to pure medium pH (P > 0.05). In histological analysis, there was a significant difference in the amount of adhered cells on FDB between the two cultivation methods (P < 0.05). The MSCs in the dynamic co-culture method demonstrated greater adhesion on the bone surface than in static co-culture method. On day 0, the cell viability in the dynamic system was significantly higher than in the static system (P < 0.05). There was a statistical difference in cell viability between days 0, 3 and 6 after dynamic culture (P < 0.05). In static culture, cell viability on day 6 was significantly lower than on day 3 and 0 (P < 0.05).

CONCLUSION

An alternative cultivation method was developed to improve the MSCs adhesion on FDB, demonstrating that dynamic co-culture provides a superior environment over static conditions.

Conditionally immortalized mouse embryonic fibroblasts retain proliferative activity without compromising multipotent differentiation potential

Mesenchymal stem cells (MSCs) are multipotent cells which reside in many tissues and can give rise to multiple lineages including bone, cartilage and adipose. Although MSCs have attracted significant attention for basic and translational research, primary MSCs have limited life span in culture which hampers MSCs' broader applications. Here, we investigate if mouse mesenchymal progenitors can be conditionally immortalized with SV40 large T antigen and maintain long-term cell proliferation without compromising their multipotency. Using the system which expresses SV40 large T antigen flanked with Cre/loxP sites, we demonstrate that mouse embryonic fibroblasts (MEFs) can be efficiently immortalized by SV40 large T antigen. The conditionally immortalized MEFs (iMEFs) exhibit an enhanced proliferative activity and maintain long-term cell proliferation, which can be reversed by Cre recombinase. The iMEFs express most MSC markers and retain multipotency as they can differentiate into osteogenic, chondrogenic and adipogenic lineages under appropriate differentiation conditions in vitro and in vivo. The removal of SV40 large T reduces the differentiation potential of iMEFs possibly due to the decreased progenitor expansion. Furthermore, the iMEFs are apparently not tumorigenic when they are subcutaneously injected into athymic nude mice. Thus, the conditionally immortalized iMEFs not only maintain long-term cell proliferation but also retain the ability to differentiate into multiple lineages. Our results suggest that the reversible immortalization strategy using SV40 large T antigen may be an efficient and safe approach to establishing long-term cell culture of primary mesenchymal progenitors for basic and translational research, as well as for potential clinical applications.

Both immediate and delayed intracavernous injection of autologous adipose-derived stromal vascular fraction enhances recovery of erectile function in a rat model of cavernous nerve injury

BACKGROUND

Intracavernous injection of cultured adipose-derived stem cells (ADSCs) effectively restores erectile function in cavernous nerve (CN)-injured rats when administered at the time of injury. However, culturing exposes ADSCs to the risk of contamination and dedifferentiation.

OBJECTIVE

Explore the effect of uncultured autologous adipose-derived stromal vascular fraction (SVF) on improving erectile function in a rat model of CN injury when administered at the time of injury or 4 wk after injury.

DESIGN, SETTING, AND PARTICIPANTS

Eighty-nine male Sprague Dawley rats were randomly divided into four groups. CN injury or sham surgery was performed at the start of the study, and rats were treated with either SVF or vehicle. Functional testing and histologic analysis were performed 12 wk after CN crush or sham surgery.

INTERVENTION

We used intracavernous injection of saline immediately after CN crush (n=23), intracavernous injection of SVF immediately after CN crush (n=17), intracavernous injection of SVF 4 wk after CN crush (n=23), or sham surgery (n=26).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We studied intracavernous pressure (ICP) response to CN electrostimulation and performed histologic examination of midpenile cross-sections. Data were analyzed using one-way analysis of variance followed by the Tukey-Kramer test.

RESULTS AND LIMITATIONS

Both immediate and delayed treatment with SVF resulted in a significantly increased ICP-to-mean arterial pressure ratio compared with the vehicle-treated group. Both immediate and delayed treatment with SVF significantly increased expression of neuronal nitric oxide synthase and neurofilament in dorsal penile nerves compared to the vehicle group. Furthermore, the smooth muscle-to-collagen ratio within the corpus cavernosum was significantly improved in both of the SVF groups compared to vehicle-treated rats. The main limitation of the study is the lack of determination of the SVF components.

CONCLUSIONS

Uncultured autologous SVF injected immediately or 4 wk after CN crush improved erectile function, promoted nerve regeneration, and prevented fibrosis of the corpus cavernosum following CN injury.

Challenges for the Therapeutic use of Pluripotent Stem Derived Cells

Human embryonic stem cells (hESC) and induced pluripotent stem cells (hiPSC) are an attractive cell source for regenerative medicine. These cells can be expanded to vast numbers and can be differentiated to many desired pluripotent stem cells (PSC) derived therapeutic cells. Cell replacement bears promises, but also challenges. The introduction of exogenous cells in a recipient must address several different topics; its safety, the exclusion of tumor formation, the immunological response and possible rejection, the cells cleanliness and their biological quality, and quantity representing the functionality of the PSC derived therapeutic cells. Tumor formation requires the removal of any PSC remaining after differentiation. Immunological rejection can be addressed with immunomodulation of the cells and the recipient. Cleanliness can be optimized using good manufacturing practice quality systems. At last, the functionality of the cells must be tested in in vitro and in animal models. After addressing these challenges, precise strategies are developed to monitor the status of the cells at different times and in case of undesired results, corresponding counteracting strategies must exist before any clinical attempt.

Concise review: role of mesenchymal stem cells in wound repair

Wound healing requires a coordinated interplay among cells, growth factors, and extracellular matrix proteins. Central to this process is the endogenous mesenchymal stem cell (MSC), which coordinates the repair response by recruiting other host cells and secreting growth factors and matrix proteins. MSCs are self-renewing multipotent stem cells that can differentiate into various lineages of mesenchymal origin such as bone, cartilage, tendon, and fat. In addition to multilineage differentiation capacity, MSCs regulate immune response and inflammation and possess powerful tissue protective and reparative mechanisms, making these cells attractive for treatment of different diseases. The beneficial effect of exogenous MSCs on wound healing was observed in a variety of animal models and in reported clinical cases. Specifically, they have been successfully used to treat chronic wounds and stimulate stalled healing processes. Recent studies revealed that human placental membranes are a rich source of MSCs for tissue regeneration and repair. This review provides a concise summary of current knowledge of biological properties of MSCs and describes the use of MSCs for wound healing. In particular, the scope of this review focuses on the role MSCs have in each phase of the wound-healing process. In addition, characterization of MSCs containing skin substitutes is described, demonstrating the presence of key growth factors and cytokines uniquely suited to aid in wound repair.

Advances in polymeric systems for tissue engineering and biomedical applications

The characteristics of tissue engineered scaffolds are major concerns in the quest to fabricate ideal scaffolds for tissue engineering applications. The polymer scaffolds employed for tissue engineering applications should possess multifunctional properties such as biocompatibility, biodegradability and favorable mechanical properties as it comes in direct contact with the body fluids in vivo. Additionally, the polymer system should also possess biomimetic architecture and should support stem cell adhesion, proliferation and differentiation. As the progress in polymer technology continues, polymeric biomaterials have taken characteristics more closely related to that desired for tissue engineering and clinical needs. Stimuli responsive polymers also termed as smart biomaterials respond to stimuli such as pH, temperature, enzyme, antigen, glucose and electrical stimuli that are inherently present in living systems. This review highlights the exciting advancements in these polymeric systems that relate to biological and tissue engineering applications. Additionally, several aspects of technology namely scaffold fabrication methods and surface modifications to confer biological functionality to the polymers have also been discussed. The ultimate objective is to emphasize on these underutilized adaptive behaviors of the polymers so that novel applications and new generations of smart polymeric materials can be realized for biomedical and tissue engineering applications.

Oncogenic role and therapeutic target of leptin signaling in breast cancer and cancer stem cells

Significant correlations between obesity and incidence of various cancers have been reported. Obesity, considered a mild inflammatory process, is characterized by a high level of secretion of several cytokines from adipose tissue. These molecules have disparate effects, which could be relevant to cancer development. Among the inflammatory molecules, leptin, mainly produced by adipose tissue and overexpressed with its receptor (Ob-R) in cancer cells is the most studied adipokine. Mutations of leptin or Ob-R genes associated with obesity or cancer are rarely found. However, leptin is an anti-apoptotic molecule in many cell types, and its central roles in obesity-related cancers are based on its pro-angiogenic, pro-inflammatory and mitogenic actions. Notably, these leptin actions are commonly reinforced through entangled crosstalk with multiple oncogenes, cytokines and growth factors. Leptin-induced signals comprise several pathways commonly triggered by many cytokines (i.e., canonical: JAK2/STAT; MAPK/ERK1/2 and PI-3K/AKT1 and, non-canonical signaling pathways: PKC, JNK and p38 MAP kinase). Each of these leptin-induced signals is essential to its biological effects on food intake, energy balance, adiposity, immune and endocrine systems, as well as oncogenesis. This review is mainly focused on the current knowledge of the oncogenic role of leptin in breast cancer. Additionally, leptin pro-angiogenic molecular mechanisms and its potential role in breast cancer stem cells will be reviewed. Strict biunivocal binding-affinity and activation of leptin/Ob-R complex makes it a unique molecular target for prevention and treatment of breast cancer, particularly in obesity contexts.

Oncogenic role and therapeutic target of leptin signaling in breast cancer and cancer stem cells

Significant correlations between obesity and incidence of various cancers have been reported. Obesity, considered a mild inflammatory process, is characterized by a high level of secretion of several cytokines from adipose tissue. These molecules have disparate effects, which could be relevant to cancer development. Among the inflammatory molecules, leptin, mainly produced by adipose tissue and overexpressed with its receptor (Ob-R) in cancer cells is the most studied adipokine. Mutations of leptin or Ob-R genes associated with obesity or cancer are rarely found. However, leptin is an anti-apoptotic molecule in many cell types, and its central roles in obesity-related cancers are based on its pro-angiogenic, pro-inflammatory and mitogenic actions. Notably, these leptin actions are commonly reinforced through entangled crosstalk with multiple oncogenes, cytokines and growth factors. Leptin-induced signals comprise several pathways commonly triggered by many cytokines (i.e., canonical: JAK2/STAT; MAPK/ERK1/2 and PI-3K/AKT1 and, non-canonical signaling pathways: PKC, JNK and p38 MAP kinase). Each of these leptin-induced signals is essential to its biological effects on food intake, energy balance, adiposity, immune and endocrine systems, as well as oncogenesis. This review is mainly focused on the current knowledge of the oncogenic role of leptin in breast cancer. Additionally, leptin pro-angiogenic molecular mechanisms and its potential role in breast cancer stem cells will be reviewed. Strict biunivocal binding-affinity and activation of leptin/Ob-R complex makes it a unique molecular target for prevention and treatment of breast cancer, particularly in obesity contexts.

Mesenchymal stem cells and cardiovascular disease: a bench to bedside roadmap

In recent years, the incredible boost in stem cell research has kindled the expectations of both patients and physicians. Mesenchymal progenitors, owing to their availability, ease of manipulation, and therapeutic potential, have become one of the most attractive options for the treatment of a wide range of diseases, from cartilage defects to cardiac disorders. Moreover, their immunomodulatory capacity has opened up their allogenic use, consequently broadening the possibilities for their application. In this review, we will focus on their use in the therapy of myocardial infarction, looking at their characteristics, in vitro and in vivo mechanisms of action, as well as clinical trials.

BDNF blended chitosan scaffolds for human umbilical cord MSC transplants in traumatic brain injury therapy

This study tested the cytotoxicity of a BDNF blended chitosan scaffold with human umbilical cord mesenchymal stem cells (hUC-MSCs), and the in vitro effect of BDNF blended chitosan scaffolds on neural stem cell differentiation with the aim of contributing alternative methods in tissue engineering for the treatment of traumatic brain injury (TBI). The chitosan scaffold based on immobilization of BDNF by genipin (GP) as a crosslinking agent referred to hereafter as a CGB scaffold was prepared by freezing-drying technique. hUC-MSCs were co-cultured with the CGB scaffold. Fluorescent nuclear staining (Hoechst 33342) was employed to determine the attachment of the hUC-MSCs to CGB scaffolds on the 1st, 3rd, 7th and 10th day of co-culture. The viability of hUC-MSCs adhered to the CGB scaffold was determined by digesting with 0.25% trypsin and evaluating with the cell counting kit-8 (CCK-8). Prior to this, the diameter and porosity of CGB scaffolds were measured. The amount of BDNF released from CGB over a 30 day period was determined by ELISA. Finally, we investigated whether the released BDNF can induce NSC to differentiate into neurons. There were no significant differences in diameter and porosity of individual CGB scaffolds (P > 0.05). There were on average more cells on the CGB scaffold on the first day than on any other day sampled (P < 0.05). The CGB scaffolds released BDNF in a uniform profile, whereas the CB scaffolds only released BDNF during the first 3 days. BDNF released from CGB scaffold promoted neuronal differentiation of NSCs and led to significant differences in differentiation rate and average neuron perimeter compared with the control group. The results of this study demonstrate that CGB scaffolds are biocompatible with hUC-MSCs and that granular CGB scaffolds covered with hUC-MSCs are expected to generate new advances for future treatment of traumatic brain injury.

Stem cell therapy for stress urinary incontinence: a critical review

Stress urinary incontinence (SUI) is a prevailing health problem that severely impacts quality of life. Because SUI is mainly due to urethral sphincter deficiency, several preclinical and clinical trials have investigated whether transplantation of patient's own skeletal muscle-derived cells (SkMDCs) can restore the sphincter musculature. The specific cell type of SkMDCs has been described as myoblasts, satellite cells, muscle progenitor cells, or muscle-derived stem cells, and thus may vary from study to study. In more recent years, other stem cell (SC) types have also been tested, including those from the bone marrow, umbilical cord blood, and adipose tissue. These studies were mostly preclinical and utilized rat SUI models that were established predominantly by pudendal or sciatic nerve injury. Less frequently used animal models were sphincter injury and vaginal distension. While transurethral injection of SCs was employed almost exclusively in clinical trials, periurethral injection was used in all preclinical trials. Intravenous injection was also used in one preclinical study. Functional assessment of therapeutic efficacy in preclinical studies has relied almost exclusively on leak point pressure measurement. Histological assessment examined the sphincter muscle content, existence of transplanted SCs, and possible differentiation of these SCs. While all of these studies reported favorable functional and histological outcomes, there are questions about the validity of the animal model and claims of multilineage differentiation. In any event, SC transplantation appears to be a promising treatment for SUI.

In vivo imaging of cell transplants in experimental ischemia

The therapeutic potential of stem cells for regeneration after cerebral lesion has become of great interest. This is particularly so for neurodegenerative diseases as well as for stroke. Contrary to more conventional, cerebroprotective treatment approaches, the focus of regeneration lies in a longer time window during the chronic phase of the lesion evolution. Thus, in order to assess the true potential of a treatment strategy and to investigate the underlying mechanisms, observation of the temporal profile of both the cell dynamics as well as the organ response to the treatment is of paramount importance. This need for intraindividual longitudinal studies can be optimally met by the application of noninvasive imaging modalities. This chapter presents in breadth the potential of noninvasive imaging modalities for cell tracking with application focus to experimental stroke. While the lion's share of discussed studies is based on MRI, we have also included the contributions of positron emission tomography and of the increasingly important optical imaging modality.

Advantages and challenges of alternative sources of adult-derived stem cells for brain repair in stroke

Considerable promise has been demonstrated by cell therapy for the treatment of stroke. Adult-derived stem cells avoid the ethical dilemmas of using embryonic and fetal stem cells and thus are the ideal type of cell to study. There are a number of different types of stem cells that could prove to be useful, but there are potential concerns associated with each one. This review summarizes the current knowledge on the use of the different possible adult-derived stem cell types including their benefits and challenges. While the optimal conditions are still to be determined, these cells may prove to be at the forefront of stem cell research and ultimately therapy for stroke and other disorders.

Stem cells: novel players in the treatment of erectile dysfunction

Stem cells are defined by their capacity for both self-renewal and directed differentiation; thus, they represent great promise for regenerative medicine. Historically, stem cells have been categorized as either embryonic stem cells (ESCs) or adult stem cells (ASCs). It was previously believed that only ESCs hold the ability to differentiate into any cell type, whereas ASCs have the capacity to give rise only to cells of a given germ layer. More recently, however, numerous studies demonstrated the ability of ASCs to differentiate into cell types beyond their tissue origin. The aim of this review was to summarize contemporary evidence regarding stem cell availability, differentiation, and more specifically, the potential of these cells in the diagnosis and treatment of erectile dysfunction (ED) in both animal models and human research. We performed a search on PubMed for articles related to definition, localisation and circulation of stem cells as well as the application of stem cells in both diagnosis and treatment of ED. Strong evidence supports the concept that stem cell therapy is potentially the next therapeutic approach for ED. To date, a large spectrum of stem cells, including bone marrow mesenchymal stem cells, adipose tissue-derived stem cells and muscle-derived stem cells, have been investigated for neural, vascular, endothelial or smooth muscle regeneration in animal models for ED. In addition, several subtypes of ASCs are localized in the penis, and circulating endogenous stem cells can be employed to predict the outcome of ED and ED-related cardiovascular diseases.

Comparative analysis of nuclear transfer embryo-derived mouse embryonic stem cells. Part I: cellular characterization

Embryonic stem cells derived from nuclear transfer embryos (ntESCs) are particularly valuable for regenerative medicine, as they are a patient-specific and histocompatible cell source for the treatment of varying diseases. However, currently, little is known about their cellular and molecular profile. In the present study, in a mouse model different donor cell-derived ntESCs from various genetic backgrounds were compared with reference ESCs and analyzed comprehensively at the cellular level. A number of pluripotency marker genes were compared by flow cytometry and immunocytochemistry analysis. Significant differences at the protein level were observed for POU5F1, SOX2, FGF4, NANOG, and SSEA-1. However, such differences had no effect on in vitro cell differentiation and cell fate: derivatives of the three germ layers were detected in all ntESC lines. The neural and cardiac in vitro differentiation revealed minor differences between the cell lines, both at the mRNA and protein level. Karyotype analyses and cell growth studies did not reveal any significant variations. Despite some differences observed, the present study revealed that ntESC lines had similar differentiation competences compared to other ESCs. The results indicate that the observed differences may be related to the genotype rather than to the nuclear transfer technology.

Biomimetic surface modification of titanium surfaces for early cell capture by advanced electrospinning

The time required for osseointegration with a metal implant having a smooth surface ranges from three to six months. We hypothesized that biomimetic coating surfaces with poly(lactic-co-glycolic acid) (PLGA)/collagen fibers and nano-hydroxyapatite (n-HA) on the implant would enhance the adhesion of mesenchymal stem cells. Therefore, this surface modification of dental and bone implants might enhance the process of osseointegration. In this study, we coated PLGA or PLGA/collagen (50:50 w/w ratio) fiber on Ti disks by modified electrospinning for 5 s to 2 min; after that, we further deposited n-HA on the fibers. PLGA fibers of fiber diameter 0.957 ± 0.357 µm had a contact angle of 9.9 ± 0.3° and PLGA/collagen fibers of fiber diameter 0.378 ± 0.068 µm had a contact angle of 0°. Upon n-HA incorporation, all the fibers had a contact angle of 0° owing to the hydrophilic nature of n-HA biomolecule. The cell attachment efficiency was tested on all the scaffolds for different intervals of time (10, 20, 30 and 60 min). The alkaline phosphatase activity, cell proliferation and mineralization were analyzed on all the implant surfaces on days 7, 14 and 21. Results of the cell adhesion study indicated that the cell adhesion was maximum on the implant surface coated with PLGA/collagen fibers deposited with n-HA compared to the other scaffolds. Within a short span of 60 min, 75% of the cells adhered onto the mineralized PLGA/collagen fibers. Similarly by day 21, the rate of cell proliferation was significantly higher (p ⩽ 0.05) on the mineralized PLGA/collagen fibers owing to enhanced cell adhesion on these fibers. This enhanced initial cell adhesion favored higher cell proliferation, differentiation and mineralization on the implant surface coated with mineralized PLGA/collagen fibers.

Alternative origins of stroma in normal organs and disease

Stromal fibroblasts are a new prospective drug target. Mesenchymal stromal cells (MSCs) and monocyte-derived stromal cells, also known as fibrocytes, are distinct fibroblastic populations derived from separate lineages. Mesenchymal and myeloid fibroblast progenitors are multipotent, serve as progenitor cells in animal models, and are implicated in several diseases. In addition, epithelial-mesenchymal transition (EMT) has been established as a mechanism for generation of stromal cells. Organ sources, relative contributions, and functions of these populations in normal development and pathology are not well understood. Innovative approaches are needed to identify markers that can distinguish these stromal populations.

Multipotent stromal cell therapy for cavernous nerve injury-induced erectile dysfunction

INTRODUCTION

Erectile dysfunction (ED) following radical prostatectomy (RP) is a result of inadvertent damage to the cavernous nerves that run close to the prostate capsula. The mechanisms behind the development of post-RP ED are increasingly recognized and include cavernosal fibrosis and cavernosal smooth muscle apoptosis, resulting from cavernous nerve degeneration due to neuropraxia. In recent years, cell-based therapies have received increasing attention regarding their potential for recovery of erectile function following cavernous nerve injury (CNI). Multipotent stromal cells (MSCs) are an attractive cell source for this application based on their regenerative potential and their clinical applicability.

AIM

To review available evidence on the efficacy and mechanisms of action of MSC application for the treatment of ED, with an emphasis on ED following CNI.

METHODS

A nonsystematic review was conducted on the available English literature between 1966 and 2011 on the search engines SciVerse-sciencedirect, SciVerse-scopus, Google Scholar, and PubMed.

RESULTS

MSCs from both bone marrow and adipose tissue have shown beneficial effects in a variety of animal models for ED. While MSC application in chronic disease models such as diabetes, aging, and hyperlipidemia may result in cell engraftment and possibly MSC differentiation, this observation has not been made in the acute CNI rat model. In the latter setting, MSC effects seem to be established by cell recruitment toward the major pelvic ganglion and local paracrine interaction with the host neural tissue.

CONCLUSIONS

While the type of model may influence the mechanisms of action of this MSC-based therapy, MSCs generally display efficacy in various animal models for ED. Before translation to the clinic is established, various hurdles need to be overcome.

The immunomodulatory capacity of mesenchymal stem cells

Mesenchymal stem cells (MSCs) are currently being tested in clinical trials for the treatment of various diseases owing to the ease of generating and expanding these cells, the ability to differentiate them into various specialized mesenchymal tissue types and their immunosuppressive properties. However, their immunomodulatory potential remains controversial. This review describes the constitutive and regulated expression of molecules of the major histocompatibility complex (MHC) class I antigen processing machinery (APM), co-stimulatory B7 molecules and HLA-G. Furthermore, this review focuses on the secretion of factors, such as cytokines, in mesenchymal stem cells, their functional role in mounting and controlling immune responses mediated by different immune cell subpopulations, their medical significance, and the obstacles that limit their clinical application.

Molecular mechanisms of cancer development in obesity

The increasing incidence of obesity and its co-morbid conditions poses a great challenge to global health. In addition to cardiovascular disease and diabetes, epidemiological data demonstrate a link between obesity and multiple types of cancer. The molecular mechanisms underlying how obesity causes an increased risk of cancer are poorly understood. Obesity disrupts the dynamic role of the adipocyte in energy homeostasis, resulting in inflammation and alteration of adipokine (for example, leptin and adiponectin) signalling. Additionally, obesity causes secondary changes that are related to insulin signalling and lipid deregulation that may also foster cancer development. Understanding these molecular links may provide an avenue for preventive and therapeutic strategies to reduce cancer risk and mortality in an increasingly obese population.

A toxicity study of multiple-administration human umbilical cord mesenchymal stem cells in cynomolgus monkeys

Therapies based on stem cells have shown very attractive potential in many clinical studies. However, the data about the safety of stem cells application remains insufficient. The present study was designed to evaluate the overall toxicology of human umbilical cord mesenchymal stem cells (hUC-MSCs) in cynomolgus monkeys with repeated administrations. hUC-MSCs were administered by intravenous injection once every 2 weeks for 6 weeks. The dose levels employed in this study were 2×10(6), 1×10(7) cells/kg body weight. Toxicity was evaluated by clinical observations (body weight, body temperature, and ophthalmology exams), pathology (blood cell counts, clinical biochemistry, urinalysis, and bone marrow smears), immunologic consequences (lymphoproliferation assay, the secretion of interferon-γ and interleukin-4, the percentage of CD3, CD4, CD8 T cells, and the ratio of CD4 and CD8 T cells) and anatomic pathology. Pharmacodynamics in blood and distribution of hUC-MSCs in the tissues of cynomolgus monkeys were measured by real-time polymerase chain reaction. All animals survived until scheduled euthanasia. No stem cells transplantation-related toxicity was found in this study. hUC-MSCs could be found in the blood of cynomolgus monkeys beyond 8 h. The findings of this 6-week toxicity study showed that the transplantation of hUC-MSCs did not affect the general health of cynomolgus monkeys.

An engineered approach to stem cell culture: automating the decision process for real-time adaptive subculture of stem cells

Current cell culture practices are dependent upon human operators and remain laborious and highly subjective, resulting in large variations and inconsistent outcomes, especially when using visual assessments of cell confluency to determine the appropriate time to subculture cells. Although efforts to automate cell culture with robotic systems are underway, the majority of such systems still require human intervention to determine when to subculture. Thus, it is necessary to accurately and objectively determine the appropriate time for cell passaging. Optimal stem cell culturing that maintains cell pluripotency while maximizing cell yields will be especially important for efficient, cost-effective stem cell-based therapies. Toward this goal we developed a real-time computer vision-based system that monitors the degree of cell confluency with a precision of 0.791±0.031 and recall of 0.559±0.043. The system consists of an automated phase-contrast time-lapse microscope and a server. Multiple dishes are sequentially imaged and the data is uploaded to the server that performs computer vision processing, predicts when cells will exceed a pre-defined threshold for optimal cell confluency, and provides a Web-based interface for remote cell culture monitoring. Human operators are also notified via text messaging and e-mail 4 hours prior to reaching this threshold and immediately upon reaching this threshold. This system was successfully used to direct the expansion of a paradigm stem cell population, C2C12 cells. Computer-directed and human-directed control subcultures required 3 serial cultures to achieve the theoretical target cell yield of 50 million C2C12 cells and showed no difference for myogenic and osteogenic differentiation. This automated vision-based system has potential as a tool toward adaptive real-time control of subculturing, cell culture optimization and quality assurance/quality control, and it could be integrated with current and developing robotic cell cultures systems to achieve complete automation.

Identification of active and quiescent adipose vascular stromal cells

BACKGROUND AIMS

Recent studies have demonstrated the existence of both active and quiescent stem cells in bone marrow, hair follicle and intestine. We attempted to identify active and quiescent vascular stromal cells (VSC) in adipose tissue.

METHODS

For identification of active VSC, adult rats were injected intraperitoneally with thymidine analog 5-ethynyl-2-deoxyuridine (EdU) and their subcutaneous tissue harvested 3 days later. For identification of quiescent VSC, newborn rats were injected intraperitoneally with EdU and their subcutaneous tissue harvested 9 weeks later. The harvested adipose tissues were examined for the co-localization of EdU with VSC marker CD34, smooth muscle marker SMA, endothelial marker RECA and pericyte marker CD140b.

RESULTS

In adult rat adipose tissues harvested 3 days after EdU injection, there were 28.80 ± 8.70 (mean ± SD) EdU+ cells/100 × microscopic field, and approximately 6.2% of cell nuclei were labeled with EdU. The percentages of EdU+ cells expressing the following markers were approximately: 84 for CD34, 5.6 for RECA (rat endothelial marker), 3.7 for SMA and 14.8 for CD140b. In the adipose tissues of newborn rats that were harvested 9 weeks after EdU injection, the percentages of EdU+ cells expressing the following markers were approximately: 76 for CD34, 1.8 for RECA, 0 for SMA and 12.9 for CD140b. In both the short-term (active) and long-term (quiescent) EdU-labeled adipose tissues, the EdU label was consistently co-localized with CD34 and in the proximity of CD140b stain or in the adventitia.

CONCLUSIONS

Both active and quiescent VSC expressed CD34 and localized to capillaries and the adventitia of larger blood vessels.

MRI stem cell tracking for therapy in experimental cerebral ischemia

Magnetic resonance has an established role in investigations on the evolution of stroke and the assessment of therapeutic strategies in experimental animals. Here we show that the technique has also an important place for the study of stem cell-mediated regenerative therapies after stroke. We review the literature by bridging from the methodological aspects of stem cell labeling via grafting and monitoring of cell dynamics after implantation into the brain all the way to MRI's role in analyzing the stem cell-mediated functional improvement. Thus, we have aimed at a view combining the focus on the monitoring of the cell activities with the aspect of lesion evolution while including also the essence of a potential functional improvement by the implantation of stem cells following stroke.

Cloned, CD117 selected human amniotic fluid stem cells are capable of modulating the immune response

Amniotic fluid stem (AFS) cells are broadly multipotent, can be expanded extensively in culture, are not tumorigenic and can be readily cryopreserved for cell banking. Mesenchymal stem cells (MSC) show immunomodulatory activity and secrete a wide spectrum of cytokines and chemokines that suppress inflammatory responses, block mixed lymphocyte reactions (MLR) and other immune reactions, and have proven therapeutic against conditions such as graft-versus-host disease. AFS cells resemble MSCs in many respects including surface marker expression and differentiation potential. We therefore hypothesized that AFS cells may exhibit similar immunomodulatory capabilities. We present data to demonstrate that direct contact with AFS cells inhibits lymphocyte activation. In addition, we show that cell-free supernatants derived from AFS cells primed with total blood monocytes or IL-1β, a cytokine released by monocytes and essential in mediation of the inflammatory response, also inhibited lymphocyte activation. Further investigation of AFS cell-free supernatants by protein array revealed secretion of multiple factors in common with MSCs that are known to be involved in immune regulation including growth related oncogene (GRO) and monocyte chemotactic protein (MCP) family members as well as interleukin-6 (IL-6). AFS cells activated by PBMCs released several additional cytokines as compared to BM-MSCs, including macrophage inflammatory protein-3α (MIP-3α), MIP-1α and Activin. AFS cells also released higher levels of MCP-1 and lower levels of MCP-2 compared to BM-MSCs in response to IL-1β activation. This suggests that there may be some AFS-specific mechanisms of inhibition of lymphocyte activation. Our results indicate that AFS cells are able to suppress inflammatory responses in vitro and that soluble factors are an essential component in the communication between lymphocytes and AFS cells. Their extensive self-renewal capacity, possibility for banking and absence of tumorigenicity may make AFS cells a superior source of stable, well characterized “off the shelf” immunomodulatory cells for a variety of immunotherapies.

Achieving stable human stem cell engraftment and survival in the CNS: is the future of regenerative medicine immunodeficient?

There is potential for a variety of stem cell populations to mediate repair in the diseased or injured CNS; in some cases, this theoretical possibility has already transitioned to clinical safety testing. However, careful consideration of preclinical animal models is essential to provide an appropriate assessment of stem cell safety and efficacy, as well as the basic biological mechanisms of stem cell action. This article examines the lessons learned from early tissue, organ and hematopoietic grafting, the early assumptions of the stem cell and CNS fields with regard to immunoprivilege, and the history of success in stem cell transplantation into the CNS. Finally, we discuss strategies in the selection of animal models to maximize the predictive validity of preclinical safety and efficacy studies.

Stem Cell Therapy: A New Treatment for Burns?

Stem cell therapy has emerged as a promising new approach in almost every medicine specialty. This vast, heterogeneous family of cells are now both naturally (embryonic and adult stem cells) or artificially obtained (induced pluripotent stem cells or iPSCs) and their fates have become increasingly controllable, thanks to ongoing research in this passionate new field. We are at the beginning of a new era in medicine, with multiple applications for stem cell therapy, not only as a monotherapy, but also as an adjunct to other strategies, such as organ transplantation or standard drug treatment. Regrettably, serious preclinical concerns remain and differentiation, cell fusion, senescence and signalling crosstalk with growth factors and biomaterials are still challenges for this promising multidisciplinary therapeutic modality. Severe burns have several indications for stem cell therapy, including enhancement of wound healing, replacement of damaged skin and perfect skin regeneration - incorporating skin appendages and reduced fibrosis -, as well as systemic effects, such as inflammation, hypermetabolism and immunosuppression. The aim of this review is to describe well established characteristics of stem cells and to delineate new advances in the stem cell field, in the context of burn injury and wound healing.

Stem cell therapy for idiopathic pulmonary fibrosis: a protocol proposal

Background

Idiopathic pulmonary fibrosis represents a lethal form of progressive fibrotic lung disorder with gradually increasing incidence worldwide. Despite intense research efforts its pathogenesis is still elusive and controversial reflecting in the current disappointing status regarding its treatment. Patients and Methods: We report the first protocol proposal of a prospective, unicentric, non-randomized, phase Ib clinical trial to study the safety and tolerability of the adipose-derived stem cells (ADSCs) stromal vascular fraction (SVF) as a therapeutic agent in IPF. After careful patient selection based on functional criteria (forced vital capacity-FVC > 50%, diffuse lung capacity for carbon monoxide-DL_CO > 35% of the predicted values) all eligible subjects will be subjected to lipoaspiration resulting in the isolation of approximately 100- 500 gr of adipose tissue. After preparation, isolation and labelling ADSCs-SVF will be endobronchially infused to both lower lobes of the fibrotic lungs. Procedure will be repeated thrice at monthly intervals. Primary end-point represent safety and tolerability data, while exploratory secondary end-points include assessment of clinical functional and radiological status. Results: Preliminary results recently presented in the form of an abstract seem promising and tantalizing since there were no cases of clinically significant allergic reactions, infections, disease acute exacerbations or ectopic tissue formation. In addition 6 months follow-up data revealed a marginal improvement at 6-minute walking distance and forced vital capacity.

Conclusions

Adipose tissue represents an abundant, safe, ethically uncontested and potentially beneficial source of stem cells for patients with IPF. Larger multicenter phase II and III placebo-controlled clinical trials are sorely needed in order to prove efficacy. However, pilot safety studies are of major importance and represent the first hamper that should be overcome to establish a rigid basis for larger clinical trials.

Hyaluronan and fibrin biomaterial as scaffolds for neuronal differentiation of adult stem cells derived from adipose tissue and skin

Recently, we have described a simple protocol to obtain an enriched culture of adult stem cells organized in neurospheres from two post-natal tissues: skin and adipose tissue. Due to their possible application in neuronal tissue regeneration, here we tested two kinds of scaffold well known in tissue engineering application: hyaluronan based membranes and fibrin-glue meshes. Neurospheres from skin and adipose tissue were seeded onto two scaffold types: hyaluronan based membrane and fibrin-glue meshes. Neurospheres were then induced to acquire a glial and neuronal-like phenotype. Gene expression, morphological feature and chromosomal imbalance (kariotype) were analyzed and compared. Adipose and skin derived neurospheres are able to grow well and to differentiate into glial/neuron cells without any chromosomal imbalance in both scaffolds. Adult cells are able to express typical cell surface markers such as S100; GFAP; nestin; βIII tubulin; CNPase. In summary, we have demonstrated that neurospheres isolated from skin and adipose tissues are able to differentiate in glial/neuron-like cells, without any chromosomal imbalance in two scaffold types, useful for tissue engineering application: hyaluronan based membrane and fibrin-glue meshes.

Stem cell therapy for incontinence: where are we now? What is the realistic potential?

A significant number of women experience stress urinary incontinence (SUI), which greatly affects their quality of life. Recent research investigating utilization of stem cells and their derivatives for the prevention and treatment of SUI has been performed to test the effect of cell source and method of administration in several animal models of SUI. The type of stem cell, timing of optimal dose or doses after injury, mechanism of action of stem cells, and route of administration must be investigated both preclinically and clinically before stem cell therapy becomes a possible treatment for SUI, although the future of this therapy looks promising. This article reviews the progress in stem cell research for incontinence and describes areas of future work as suggested by research in other fields.

Intramuscular VEGF activates an SDF1-dependent progenitor cell cascade and an SDF1-independent muscle paracrine cascade for cardiac repair

The skeletal muscle is endowed with an impressive ability to regenerate after injury, and this ability is coupled to paracrine production of many trophic factors possessing cardiovascular benefits. Taking advantage of this humoral capacity of the muscle, we recently demonstrated an extracardiac therapeutic regimen based on intramuscular delivery of VEGF-A(165) for repair of the failing hamster heart. This distal organ repair mechanism activates production from the injected hamstring of many trophic factors, among which stromal-derived factor-1 (SDF1) prominently mobilized multi-lineage progenitor cells expressing CXCR4 and their recruitment to the heart. The mobilized bone marrow progenitor cells express the cardiac transcription factors myocyte enhancer factor 2c and GATA4 and several major trophic factors, most notably IGF1 and VEGF. SDF1 blockade abrogated myocardial recruitment of CXCR4(+) and c-kit(+) progenitor cells with an insignificant effect on the hematopoietic progenitor lineage. The knockdown of cardiac progenitor cells led to deprivation of myocardial trophic factors, resulting in compromised cardiomyogenesis and angiogenesis. However, the VEGF-injected hamstring continued to synthesize cardioprotective factors, contributing to moderate myocardial tissue viability and function even in the presence of SDF1 blockade. These findings thus uncover two distinct but synergistic cardiac therapeutic mechanisms activated by intramuscular VEGF. Whereas the SDF1/CXCR4 axis activates the progenitor cell cascade and its trophic support of cardiomyogenesis intramuscularly, VEGF amplifies the skeletal muscle paracrine cascade capable of directly promoting myocardial survival independent of SDF1. Given that recent clinical trials of cardiac repair based on the use of marrow-mobilizing agents have been disappointing, the proposed dual therapeutic modality warrants further investigation.