Distinct contribution of human cord blood-derived endothelial colony forming cells to liver and gut in a fetal sheep model

Fetal endothelial colony-forming cells: Possible targets for prevention of the fetal origins of adult diseases

Endothelial colony-forming cells (ECFCs), a subset of circulating and resident endothelial progenitor cells, are capable of self-renewal and de novo vessel formation, and are known key regulators of vascular integrity and homeostasis. Numerous studies have found that exposure to hostile environment during the fetal development exerts a profound influence on the level and function of ECFCs, which may be the underlying factor linking endothelial dysfunction to cardiovascular disease of the offspring in later life. Herein, we focus on the latest findings regarding the effects of pregnancy-related disorders on the frequency and function of fetal ECFCs. Subsequently, we discuss about placental ECFCs and put forward some details that should be paid attention to in the process of ECFC isolation and culture. Overall, the information presented in this review highlight the potential of ECFCs as a future biomarker or even therapeutic targets for the pregnancy-related adverse maternal and fetal outcomes.

Streamlined and quantitative detection of chimerism using digital PCR

Animal chimeras are widely used for biomedical discoveries, from developmental biology to cancer research. However, the accurate quantitation of mixed cell types in chimeric and mosaic tissues is complicated by sample preparation bias, transgenic silencing, phenotypic similarity, and low-throughput analytical pipelines. Here, we have developed and characterized a droplet digital PCR single-nucleotide discrimination assay to detect chimerism among common albino and non-albino mouse strains. In addition, we validated that this assay is compatible with crude lysate from all solid organs, drastically streamlining sample preparation. This chimerism detection assay has many additional advantages over existing methods including its robust nature, minimal technical bias, and ability to report the total number of cells in a prepared sample. Moreover, the concepts discussed here are readily adapted to other genomic loci to accurately measure mixed cell populations in any tissue.

Investigating Optimal Autologous Cellular Platforms for Prenatal or Perinatal Factor VIII Delivery to Treat Hemophilia A

Patients with the severe form of hemophilia A (HA) present with a severe phenotype, and can suffer from life-threatening, spontaneous hemorrhaging. While prophylactic FVIII infusions have revolutionized the clinical management of HA, this treatment is short-lived, expensive, and it is not available to many A patients worldwide. In the present study, we evaluated a panel of readily available cell types for their suitability as cellular vehicles to deliver long-lasting FVIII replacement following transduction with a retroviral vector encoding a B domain-deleted human F8 transgene. Given the immune hurdles that currently plague factor replacement therapy, we focused our investigation on cell types that we deemed to be most relevant to either prenatal or very early postnatal treatment and that could, ideally, be autologously derived. Our findings identify several promising candidates for use as cell-based FVIII delivery vehicles and lay the groundwork for future mechanistic studies to delineate bottlenecks to efficient production and secretion of FVIII following genetic-modification.

Pre-Exposure to Defibrotide Prevents Endothelial Cell Activation by Lipopolysaccharide: An Ingenuity Pathway Analysis

Defibrotide (DFB) effects on different endothelial cell pathways have been investigated focusing on a limited number of genes or molecules. This study explored the modulation of the gene expression profile of steady-state or lipopolysaccharide (LPS)-activated endothelial cells, following the DFB exposure. Starting from differentially regulated gene expression datasets, we utilized the Ingenuity Pathway Analysis (IPA) to infer novel information about the activity of this drug. We found that effects elicited by LPS deeply differ depending on cells were exposed to DFB and LPS at the same time, or if the DFB priming occurs before the LPS exposure. Only in the second case, we observed a significant down-regulation of various pathways activated by LPS. In IPA, the pathways most affected by DFB were leukocyte migration and activation, vasculogenesis, and inflammatory response. Furthermore, the activity of DFB seemed to be associated with the modulation of six key genes, including matrix-metalloproteinases 2 and 9, thrombin receptor, sphingosine-kinase1, alpha subunit of collagen XVIII, and endothelial-protein C receptor. Overall, our findings support a role for DFB in a wide range of diseases associated with an exaggerated inflammatory response of endothelial cells.

Chimeras for the twenty-first century

Recent advances in stem cell biology and molecular engineering have improved and simplified the methodology employed to create experimental chimeras, highlighting their value in basic research and broadening the spectrum of potential applications. Experimental chimeras have been used for decades during the generation of murine genetic models, this being especially relevant in developmental and regeneration studies. Indeed, their value for the research and modeling of human diseases was recognized by the 2007 Nobel Prize to Mario Capecchi, Martin Evans, and Oliver Smithies. More recently, their potential application in regenerative medicine has generated a lot of interest, particularly the enticing possibility to generate human organs for transplantation in livestock animals. In this review, we provide an update on interspecific chimeric organogenesis, its possibilities, current limitations, alternatives, and ethical issues.

MFSD2A Promotes Endothelial Generation of Inflammation-Resolving Lipid Mediators and Reduces Colitis in Mice

BACKGROUND & AIMS

Alterations in signaling pathways that regulate resolution of inflammation (resolving pathways) contribute to pathogenesis of ulcerative colitis (UC). The resolution process is regulated by lipid mediators, such as those derived from the ω-3 docosahexaenoic acid (DHA), whose esterified form is transported by the major facilitator superfamily domain containing 2A (MFSD2A) through the endothelium of brain, retina, and placenta. We investigated if and how MFSD2A regulates lipid metabolism of gut endothelial cells to promote resolution of intestinal inflammation.

METHODS

We performed lipidomic and functional analyses of MFSD2A in mucosal biopsies and primary human intestinal microvascular endothelial cells (HIMECs) isolated from surgical specimens from patients with active, resolving UC and healthy individuals without UC (controls). MFSD2A was knocked down in HIMECs with small hairpin RNAs or overexpressed from a lentiviral vector. Human circulating endothelial progenitor cells that overexpress MFSD2A were transferred to CD1 nude mice with dextran sodium sulfate-induced colitis, with or without oral administration of DHA.

RESULTS

Colonic biopsies from patients with UC had reduced levels of inflammation-resolving DHA-derived epoxy metabolites compared to healthy colon tissues or tissues with resolution of inflammation. Production of these metabolites by HIMECs required MFSD2A, which is required for DHA retention and metabolism in the gut vasculature. In mice with colitis, transplanted endothelial progenitor cells that overexpressed MFSD2A not only localized to the inflamed mucosa but also restored the ability of the endothelium to resolve intestinal inflammation, compared with mice with colitis that did not receive MFSD2A-overexpressing endothelial progenitors.

CONCLUSIONS

Levels of DHA-derived epoxides are lower in colon tissues from patients with UC than healthy and resolving mucosa. Production of these metabolites by gut endothelium requires MFSD2A; endothelial progenitor cells that overexpress MFSD2A reduce colitis in mice. This pathway might be induced to resolve intestinal inflammation in patients with colitis.

Lessons from Interspecies Mammalian Chimeras

As chimeras transform from beasts of Greek mythology into tools of contemporary bioscience, secrets of developmental biology and evolutionary divergence are being revealed. Recent advances in stem cell biology and interspecies chimerism have generated new models with extensive basic and translational applications, including generation of transplantable, patient-specific organs.

miR-193a-3p interaction with HMGB1 downregulates human endothelial cell proliferation and migration

Circulating endothelial colony forming cells (ECFCs) contribute to vascular repair where they are a target for therapy. Since ECFC proliferative potential is increased in cord versus peripheral blood and to define regulatory factors controlling this proliferation, we compared the miRNA profiles of cord blood and peripheral blood ECFC-derived cells. Of the top 25 differentially regulated miRNAs selected, 22 were more highly expressed in peripheral blood ECFC-derived cells. After validating candidate miRNAs by q-RT-PCR, we selected miR-193a-3p for further investigation. The miR-193a-3p mimic reduced cord blood ECFC-derived cell proliferation, migration and vascular tubule formation, while the miR-193a-3p inhibitor significantly enhanced these parameters in peripheral blood ECFC-derived cells. Using in silico miRNA target database analyses combined with proteome arrays and luciferase reporter assays of miR-193a-3p mimic treated cord blood ECFC-derived cells, we identified 2 novel miR-193a-3p targets, the high mobility group box-1 (HMGB1) and the hypoxia upregulated-1 (HYOU1) gene products. HMGB1 silencing in cord blood ECFC-derived cells confirmed its role in regulating vascular function. Thus, we show, for the first time, that miR-193a-3p negatively regulates human ECFC vasculo/angiogenesis and propose that antagonising miR-193a-3p in less proliferative and less angiogenic ECFC-derived cells will enhance their vasculo/angiogenic function.

Circulating Bone Marrow-Derived CD45-/CD34+/CD133+/VEGF+ Endothelial Progenitor Cells in Adults with Crohn's Disease

BACKGROUND

Circulating endothelial progenitor cells (EPCs) are bone marrow-derived stem cells able to migrate to sites of damaged endothelium and differentiate into endothelial cells. Altered EPC level and function have been described in various inflammatory diseases and have been shown to augment vasculogenesis in murine models. Previous studies of EPC in the context of Crohn's disease (CD) have yielded conflicting results.

AIM

To determine whether the circulating levels of EPCs are changed in the context of CD.

METHODS

CD patients and healthy controls were recruited. Disease activity was assessed by CDAI. Peripheral blood mononuclear cells were isolated and EPC numbers evaluated by FACS analysis using anti-CD34, anti-VEGF receptor-2, anti-CD133, and anti-CD45 markers.

RESULTS

Eighty-three subjects, including 32 CD patients and 51 controls were recruited, including 19 (59.4 %) and 23 (45 %) males (p = 0.26), aged 34.8 ± 14.9 and 43.3 ± 18.5 years (p = 0.64), in cases and controls, respectively. Mean CDAI was 147 ± 97, disease duration was 12.7 ± 11.1 years, and 28 (87.5 %) were receiving biologics for a mean duration of 21.7 ± 16.8 months. The mean level of peripheral EPCs in CD patients was 0.050 ± 0.086 percent and 0.007 ± 0.013 % in controls (p < 0.01). There was no significant correlation between EPC levels and age (r = -0.13, p = 0.47), CDAI (r = -0.26, p = 0.15), disease duration (r = -0.04, p = 0.84), or duration of treatment with biologics (r = 0.004, p = 0.99).

CONCLUSION

EPCs are elevated in patients with CD. Further studies are needed to examine the function of EPCs and their possible role as a marker of disease severity or therapeutic response.

Evaluation of PVA biodegradable electric conductive membranes for nerve regeneration in axonotmesis injuries: the rat sciatic nerve animal model

The therapeutic effect of three polyvinyl alcohol (PVA) membranes loaded with electrically conductive materials - carbon nanotubes (PVA-CNTs) and polypyrrole (PVA-PPy) - were tested in vivo for neuro-muscular regeneration after an axonotmesis injury in the rat sciatic nerve. The membranes electrical conductivity measured was 1.5 ± 0.5 × 10^-6 S/m, 579 ± 0.6 × 10^-6 S/m, and 1837.5 ± 0.7 × 10^-6 S/m, respectively. At week-12, a residual motor and nociceptive deficit were present in all treated groups, but at week-12, a better recovery to normal gait pattern of the PVA-CNTs and PVA-PPy treated groups was observed. Morphometrical analysis demonstrated that PVA-CNTs group presented higher myelin thickness and lower g-ratio. The tibialis anterior muscle, in the PVA-PPy and PVA-CNTs groups showed a 9% and 19% increase of average fiber size area and a 5% and 10% increase of the "minimal Feret's diameter," respectively. No inflammation, degeneration, fibrosis or necrosis were detected in lung, liver, kidneys, spleen, and regional lymph nodes and absence of carbon deposits was confirmed with Von Kossa and Masson-Fontana stains. In conclusion, the membranes of PVA-CNTs and PVA-PPy are biocompatible and have electrical conductivity. The higher electrical conductivity measured in PVA-CNTs membrane might be responsible for the positive results on maturation of myelinated fibers. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1267-1280, 2017.

Concise Review: Functional Definition of Endothelial Progenitor Cells: A Molecular Perspective

: Since the discovery of endothelial progenitor cells (EPCs) almost 2 decades ago, there has been great hope in their use in treating chronic ischemic disease. Unfortunately, to date, many of the clinical trials using EPCs have been hampered by the lack of clear definition of this cell population. Attributes of a progenitor population are self-renewal and multipotentiality. Major progress has been achieved moving from a definition of EPCs based on a candidate cell surface molecule to a functional definition based essentially on self-renewal hierarchy of endothelial colony-forming cells (ECFCs). More recent work has seized on this functional characterization to associate gene expression signatures with the self-renewal capacity of ECFCs. In particular, Notch signaling driving the quiescence of progenitors has been shown to be central to progenitor self-renewal. This new molecular definition has tremendous translational consequences, because progenitors have been shown to display greater vasculogenic potential. Also, this molecular definition of EPC self-renewal allows assessment of the quality of presumed EPC preparations. This promises to be the initial stage in progressing EPCs further into mainstream clinical use.

SIGNIFICANCE

The development of a therapy using endothelial progenitor cells provides great hope for patients in treating cardiovascular diseases going forward. For continual development of this therapy toward the clinical, further understanding of the fundamental biology of these cells is required. This will enable a greater understanding of their stemness capacity and provide insight into their ability to differentiate and drive tissue regeneration when injected into a host.

Therapeutic Potential of Human-Derived Endothelial Colony-Forming Cells in Animal Models

PURPOSE OF REVIEW

Tissue regeneration requires proper vascularization. In vivo studies identified that the endothelial colony-forming cells (ECFCs), a subtype of endothelial progenitor cells that can be isolated from umbilical cord or peripheral blood, represent a promising cell source for therapeutic neovascularization. ECFCs not only are able to initiate and facilitate neovascularization in diseased tissue but also can, by acting in a paracrine manner, contribute to the creation of favorable conditions for efficient and appropriate differentiation of tissue-resident stem or progenitor cells. This review outlines the progress in the field of in vivo regenerative and tissue engineering studies and surveys why, when, and how ECFCs can be used for tissue regeneration.

RECENT FINDINGS

Reviewed literature that regard human-derived ECFCs in xenogeneic animal models implicates that ECFCs should be considered as an endothelial cell source of preference for induction of neovascularization. Their neovascularization and regenerative potential is augmented in combination with other types of stem or progenitor cells. Biocompatible scaffolds prevascularized with ECFCs interconnect faster and better with the host vasculature. The physical incorporation of ECFCs in newly formed blood vessels grants prolonged release of trophic factors of interest, which also makes ECFCs an interesting cell source candidate for gene therapy and delivery of bioactive compounds in targeted area.

SUMMARY

ECFCs possess all biological features to be considered as a cell source of preference for tissue engineering and repair of blood supply. Investigation of regenerative potential of ECFCs in autologous settings in large animal models before clinical application is the next step to clearly outline the most efficient strategy for using ECFCs as treatment.

Self-Renewal and High Proliferative Colony Forming Capacity of Late-Outgrowth Endothelial Progenitors Is Regulated by Cyclin-Dependent Kinase Inhibitors Driven by Notch Signaling

Since the discovery of endothelial colony forming cells (ECFC), there has been significant interest in their therapeutic potential to treat vascular injuries. ECFC cultures display significant heterogeneity and a hierarchy among cells able to give rise to high proliferative versus low proliferative colonies. Here we aimed to define molecularly this in vitro hierarchy. Based on flow cytometry, CD34 expression levels distinguished two populations. Only CD34 + ECFC had the capacity to reproduce high proliferative potential (HPP) colonies on replating, whereas CD34- ECFCs formed only small clusters. CD34 + ECFCs were the only ones to self-renew in stringent single-cell cultures and gave rise to both CD34 + and CD34- cells. Upon replating, CD34 + ECFCs were always found at the centre of HPP colonies and were more likely in G0/1 phase of cell cycling. Functionally, CD34 + ECFC were superior at restoring perfusion and better engrafted when injected into ischemic hind limbs. Transcriptomic analysis identified cyclin-dependent kinase (CDK) cell cycle inhibiting genes (p16, p21, and p57), the Notch signaling pathway (dll1, dll4, hes1, and hey1), and the endothelial cytokine il33 as highly expressed in CD34 + ECFC. Blocking the Notch pathway using a γ-secretase inhibitor (DAPT) led to reduced expression of cell cycle inhibitors, increased cell proliferation followed by a loss of self-renewal, and HPP colony formation capacity reflecting progenitor exhaustion. Similarly shRNA knockdown of p57 strongly affected self-renewal of ECFC colonies. ECFC hierarchy is defined by Notch signalling driving cell cycle regulators, progenitor quiescence and self-renewal potential.

Scarring, stem cells, scaffolds and skin repair

The treatment of full thickness skin loss, which can be extensive in the case of large burns, continues to represent a challenging clinical entity. This is due to an on-going inability to produce a suitable tissue engineered substrate that can satisfactorily replicate the epidermal and dermal in vivo niches to fulfil both aesthetic and functional demands. The current gold standard treatment of autologous skin grafting is inadequate because of poor textural durability, scarring and associated contracture, and because of a paucity of donor sites in larger burns. Tissue engineering has seen exponential growth in recent years with a number of 'off-the-shelf' dermal and epidermal substitutes now available. Each has its own limitations. In this review, we examine normal wound repair in relation to stem/progenitor cells that are intimately involved in this process within the dermal niche. Endothelial precursors, in particular, are examined closely and their phenotype, morphology and enrichment from multiple sources are described in an attempt to provide some clarity regarding the controversy surrounding their classification and role in vasculogenesis. We also review the role of the next generation of cellularized scaffolds and smart biomaterials that attempt to improve the revascularisation of artificial grafts, the rate of wound healing and the final cosmetic and functional outcome.

Stem cell therapy in inflammatory bowel disease: A promising therapeutic strategy?

Inflammatory bowel diseases are inflammatory, chronic and progressive diseases of the intestinal tract for which no curative treatment is available. Research in other fields with stem cells of different sources and with immunoregulatory cells (regulatory T-lymphocytes and dendritic T-cells) opens up new expectations for their use in these diseases. The goal for stem cell-based therapy is to provide a permanent cure. To achieve this, it will be necessary to obtain a cellular product, original or genetically modified, that has a high migration capacity and homes into the intestine, has high survival after transplantation, regulates the immune reaction while not being visible to the patient’s immune system, and repairs the injured tissue.

Positive regulatory effects of perioperative probiotic treatment on postoperative liver complications after colorectal liver metastases surgery: a double-center and double-blind randomized clinical trial

BACKGROUND

Colorectal liver metastases (CLM) occur frequently and postoperative intestinal infection is a common complication. Our previous study showed that probiotics could decrease the rate of infectious complications after colectomy for colorectal cancer. To determine the effects of the perioperative administration of probiotics on serum zonulin levels which is a marker of intestinal permeability and the subsequent impact on postoperative infectious complications in patients with CLM.

METHODS

150 patients with CLM were randomly divided into control group (n = 68) and probiotics group (n = 66). Probiotics and placebo were given orally for 6 days preoperatively and 10 days postoperatively to control group and probiotics group respectively. We used the local resection for metastatic tumor ,while for large tumor, the segmental hepatectomy. Postoperative outcome were recorded. Furthermore, complications in patients with normal intestinal barrier function and the relation with serum zonulin were analyzed to evaluate the impact on the liver barrier dysfunction.

RESULTS

The incidence of infectious complications in the probiotics group was lower than control group. Analysis of CLM patients with normal postoperative intestinal barrier function paralleled with the serum zonulin level. And probiotics could also reduce the concentration of serum zonulin (P = 0.004) and plasma endotoxin (P < 0.001).

CONCLUSION

Perioperative probiotics treatment could reduce the serum zonulin level, the rate of postoperative septicemia and maintain the liver barrier in patients undergoing CLM surgery. we propose a new model about the regulation of probiotics to liver barrier via clinical regulatory pathway. We recommend the preoperative oral intake of probiotics combined with postoperative continued probiotics treatment in patients who undergo CLM surgery.

TRIAL REGISTRATION

ChiCTR-TRC- 12002841 . 2012/12/21.

Progress and challenges in the development of a cell-based therapy for hemophilia A

Hemophilia A results from an insufficiency of factor VIII (FVIII). Although replacement therapy with plasma-derived or recombinant FVIII is a life-saving therapy for hemophilia A patients, such therapy is a life-long treatment rather than a cure for the disease. In this review, we discuss the possibilities, progress, and challenges that remain in the development of a cell-based cure for hemophilia A. The success of cell therapy depends on the type and availability of donor cells, the age of the host and method of transplantation, and the levels of engraftment and production of FVIII by the graft. Early therapy, possibly even prenatal transplantation, may yield the highest levels of engraftment by avoiding immunological rejection of the graft. Potential cell sources of FVIII include a specialized subset of endothelial cells known as liver sinusoidal endothelial cells (LSECs) present in the adult and fetal liver, or patient-specific endothelial cells derived from induced pluripotent stem cells that have undergone gene editing to produce FVIII. Achieving sufficient engraftment of transplanted LSECs is one of the obstacles to successful cell therapy for hemophilia A. We discuss recent results from transplants performed in animals that show production of functional and clinically relevant levels of FVIII obtained from donor LSECs. Hence, the possibility of treating hemophilia A can be envisioned through persistent production of FVIII from transplanted donor cells derived from a number of potential cell sources or through creation of donor endothelial cells from patient-specific induced pluripotent stem cells.

Regenerative medicine: prospects for the treatment of inflammatory bowel disease

This article reviews the current understanding of the processes driving the development and progression of inflammatory bowel disease (IBD), discusses how the dynamic crosstalk between resident microorganisms, host cells and the immune system is required in order to maintain immune homeostasis, and considers innovative strategies that allow the modification or modulation of the intestinal microorganismal community as a potential approach for treating IBD. This article next rationalizes the use of cell-based regenerative medicine as treatment for IBD, discusses the obstacles hindering its success, summarizes some of the results of recent clinical trials employing these therapies, and discusses ongoing work to enhance mesenchymal stem/stromal cells, making them better suited to the task of repairing the damage within the IBD gut.

Perspectives of employing mesenchymal stem cells from the Wharton's jelly of the umbilical cord for peripheral nerve repair

Mesenchymal stem cells (MSCs) from Wharton's jelly present high plasticity and low immunogenicity, turning them into a desirable form of cell therapy for the injured nervous system. Their isolation, expansion, and characterization have been performed from cryopreserved umbilical cord tissue. Great concern has been dedicated to the collection, preservation, and transport protocols of the umbilical cord after the parturition to the laboratory in order to obtain samples with higher number of viable MSCs without microbiological contamination. Different biomaterials like chitosan-silicate hybrid, collagen, PLGA90:10, poly(DL-lactide-ɛ-caprolactone), and poly(vinyl alcohol) loaded with electrical conductive materials, associated to MSCs have also been tested in the rat sciatic nerve in axonotmesis and neurotmesis lesions. The in vitro studies of the scaffolds included citocompatibility evaluation of the biomaterials used and cell characterization by imunocytochemistry, karyotype analysis, differentiation capacity into neuroglial-like cells, and flow cytometry. The regeneration process follow-up has been performed by functional analysis and the repaired nerves processed for stereological studies permitted the morphologic regeneration evaluation. The MSCs from Wharton's jelly delivered through tested biomaterials should be regarded a potentially valuable tool to improve clinical outcome especially after trauma to sensory nerves. In addition, these cells represent a noncontroversial source of primitive mesenchymal progenitor cells, which can be harvested after birth, cryogenically stored, thawed, and expanded for therapeutic uses. The importance of a longitudinal study concerning tissue engineering of the peripheral nerve, which includes a multidisciplinary team able to develop biomaterials associated to cell therapies, to perform preclinical trials concerning animal welfare and the appropriate animal model is here enhanced.

Concise review: clinical programs of stem cell therapies for liver and pancreas

Regenerative medicine is transitioning into clinical programs using stem/progenitor cell therapies for repair of damaged organs. We summarize those for liver and pancreas, organs that share endodermal stem cell populations, biliary tree stem cells (hBTSCs), located in peribiliary glands. They are precursors to hepatic stem/progenitors in canals of Hering and to committed progenitors in pancreatic duct glands. They give rise to maturational lineages along a radial axis within bile duct walls and a proximal-to-distal axis starting at the duodenum and ending with mature cells in the liver or pancreas. Clinical trials have been ongoing for years assessing effects of determined stem cells (fetal-liver-derived hepatic stem/progenitors) transplanted into the hepatic artery of patients with various liver diseases. Immunosuppression was not required. Control subjects, those given standard of care for a given condition, all died within a year or deteriorated in their liver functions. Subjects transplanted with 100-150 million hepatic stem/progenitor cells had improved liver functions and survival extending for several years. Full evaluations of safety and efficacy of transplants are still in progress. Determined stem cell therapies for diabetes using hBTSCs remain to be explored but are likely to occur following ongoing preclinical studies. In addition, mesenchymal stem cells (MSCs) and hematopoietic stem cells (HSCs) are being used for patients with chronic liver conditions or with diabetes. MSCs have demonstrated significant effects through paracrine signaling of trophic and immunomodulatory factors, and there is limited evidence for inefficient lineage restriction into mature parenchymal or islet cells. HSCs' effects are primarily via modulation of immune mechanisms.