Effects of transplanted bone marrow mesenchymal stem cells on the irradiated intestine of mice. J Biomed Sci. 2008;15:585-594. [PMID: 18763056 DOI: 10.1007/s11373-008-9256-9]

Proenkephalin deletion in hematopoietic cells induces intestinal barrier failure resulting in clinical feature similarities with irritable bowel syndrome in mice

Opioid-dependent immune-mediated analgesic effects have been broadly reported upon inflammation. In preclinical mouse models of intestinal inflammatory diseases, the local release of enkephalins (endogenous opioids) by colitogenic T lymphocytes alleviate inflammation-induced pain by down-modulating gut-innervating nociceptor activation in periphery. In this study, we wondered whether this immune cell-derived enkephalin-mediated regulation of the nociceptor activity also operates under steady state conditions. Here, we show that chimeric mice engrafted with enkephalin-deficient bone marrow cells exhibit not only visceral hypersensitivity but also an increase in both epithelial paracellular and transcellular permeability, an alteration of the microbial topography resulting in increased bacteria-epithelium interactions and a higher frequency of IgA-producing plasma cells in Peyer's patches. All these alterations of the intestinal homeostasis are associated with an anxiety-like behavior despite the absence of an overt inflammation as observed in patients with irritable bowel syndrome. Thus, our results show that immune cell-derived enkephalins play a pivotal role in maintaining gut homeostasis and normal behavior in mice. Because a defect in the mucosal opioid system remarkably mimics some major clinical symptoms of the irritable bowel syndrome, its identification might help to stratify subgroups of patients.

Unrecognized digestive toxicities of radiation therapy

The aim of this article is to review unrecognized toxicities resulting from radiation therapy of digestive neoplasms. Due to their precocious occurrence, acute toxicities are well-known by radiation oncologist, and their treatment well-established. Thus, acute toxicities will not be described in this review. We will focus on incidence, diagnosis, and management of late and uncommon toxicities occurring in the digestive tract and digestive organs. Prevention, by respecting healthy tissues constraints, is the main tool to reduce incidence of those rare complications. Nonetheless, once installed, late toxicities remain a major burden in terms of quality of life and can even be life threatening. Hence, information and education about their diagnosis and management is important.

Photobiomodulation Enhances the Angiogenic Effect of Mesenchymal Stem Cells to Mitigate Radiation-Induced Enteropathy

Radiation-induced enteropathy remains a major complication after accidental or therapeutic exposure to ionizing radiation. Recent evidence suggests that intestinal microvascular damage significantly affects the development of radiation enteropathy. Mesenchymal stem cell (MSC) therapy is a promising tool to regenerate various tissues, including skin and intestine. Further, photobiomodulation (PBM), or low-level light therapy, can accelerate wound healing, especially by stimulating angiogenesis, and stem cells are particularly susceptible to PBM. Here, we explored the effect of PBM on the therapeutic potential of MSCs for the management of radiation enteropathy. In vitro, using human umbilical cord blood-derived MSCs, PBM increased proliferation and self-renewal. Intriguingly, the conditioned medium from MSCs treated with PBM attenuated irradiation-induced apoptosis and impaired tube formation in vascular endothelial cells, and these protective effects were associated with the upregulation of several angiogenic factors. In a mouse model of radiation-induced enteropathy, treatment with PBM-preconditioned MSCs alleviated mucosal destruction, improved crypt cell proliferation and epithelial barrier functions, and significantly attenuated the loss of microvascular endothelial cells in the irradiated intestinal mucosa. This treatment also significantly increased angiogenesis in the lamina propria. Together, we suggest that PBM enhances the angiogenic potential of MSCs, leading to improved therapeutic efficacy for the treatment of radiation-induced enteropathy.

Morpho-Functional Characteristics of Bone Marrow Multipotent Mesenchymal Stromal Cells after Activation or Inhibition of Epidermal Growth Factor and Toll-Like Receptors or Treatment with DNA Intercalator Cisplatin

This study is aimed to reveal morphological and functional changes in multipotent mesenchymal stromal cells (MSCs) isolated from the rat bone marrow after: (i) activation of Toll-like receptors (TLRs) with teichoic acid (TA), (ii) impact on epidermal growth factor (EGF) receptors with activator EGF or inhibitor Herceptin, and (iii) treatment with DNA intercalator Cisplatin. According to our results, TA and EGF cause an increase in the synthesis of glycosaminoglycans, c-Myc content, and protein in the MSC cytoplasm. It was observed that the cell population in G0 phase decreased and the cell population in G1 phase increased, when compared with control. At the same time, the cell population with a higher nuclear-cytoplasmic ratio (NCR) in S and G2 phases also increased. This indicates the manifestation of the MSC mesenchymal phenotype, exhibiting indirect metabolic signs of the regenerative potential increase. In other experiments, Herceptin was shown to suppress only the stemness signs of MSCs, while Cisplatin seriously affected cell viability in general, reducing synthetic and proliferative activities and causing cell morphology disturbances. © 2018 International Society for Advancement of Cytometry.

Mesenchymal stem cell transplantation improves chronic colitis-associated complications through inhibiting the activity of toll-like receptor-4 in mice

Background

A variety of extra-intestinal manifestations (EIMs), including hepatobiliary complications, are associated with inflammatory bowel disease (IBD). Mesenchymal stem cells (MSCs) have been shown to play a potential role in the therapy of IBD. This study was designed to investigate the effect and mechanism of MSCs on chronic colitis-associated hepatobiliary complications using mouse chronic colitis models induced by dextran sulfate sodium (DSS).

Methods

DSS-induced mouse chronic colitis models were established and treated with MSCs. Severity of colitis was evaluated by disease activity index (DAI), body weight (BW), colon length and histopathology. Serum lipopolysaccharide (LPS) levels were detected by limulus amebocyte lysate test (LAL-test). Histology and liver function of the mice were checked correspondingly. Serum LPS levels and bacterial translocation of mesenteric lymph nodes (MLN) were detected. Pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1β (IL-1β), interleukin-17A (IL-17A), Toll receptor 4 (TLR4), TNF receptor-associated factor 6 (TRAF6) and nuclear factor kappa B (NF-κB) were detected by immunohistochemical staining, western blot analysis and real-time PCR, respectively.

Results

The DSS-induced chronic colitis model was characterized by reduced BW, high DAI, worsened histologic inflammation, and high levels of LPS and E. coli. Liver histopathological lesions, impaired liver function, enhanced proteins and mRNA levels of TNF-α, IFN-γ, IL-1β, IL-17A, TLR4, TRAF6 and NF-κB were observed after DSS administration. MSCs transplantation markedly ameliorated the pathology of colon and liver by reduction of LPS levels and proteins and mRNA expressions of TNF-α, IFN-γ, IL-1β, IL-17A, TLR4, TRAF6 and NF-κB.

Conclusions

MSCs can improve chronic colitis-associated hepatobiliary complications, probably by inhibition of enterogenous endotoxemia and hepatic inflammation through LPS/TLR4 pathway. MSCs may represent a novel therapeutic approach for chronic colitis-associated hepatobiliary complications.

Mesenchymal stem cells over-expressing cxcl12 enhance the radioresistance of the small intestine

The chemokine C-X-C motif chemokine 12 (CXCL12) greatly impacts various biological processes in mammals, including cell survival, growth and migration. Mesenchymal stem cells (MSCs) are promising tools for carrying foreign genes to treat radiation-induced injuries in the intestinal epithelium. In this study, human adipose-derived MSCs were constructed to over-express the mouse cxcl12 gene to treat such injuries. In vitro, because of the high levels of mouse CXCL12 in conditioned medium produced by mouse cxcl12 gene-modified cells, phosphorylation of Akt at Ser473 and Erk1/2 at Thr202/Thr204 was increased within crypt cells of irradiated organoids compared with unmodified controls. Moreover, intracellular stabilization of β-catenin was achieved after treatment of mouse cxcl12 gene-modified cells with conditioned medium. As a result, survival of crypt cells was maintained and their proliferation was promoted. When delivering mouse cxcl12 gene-modified cells into irradiated BALB/c nude mice, mice were rescued despite the clearance of cells from the host within 1 week. Irradiated mice that received mouse cxcl12 gene-modified MSCs exhibited reduced serum levels of interleukin-1α (IL-1α) and IL-6 as well as elevated levels of CXCL12. Additionally, epithelial recovery from radiation stress was accelerated compared with the irradiated-alone controls. Moreover, mouse cxcl12 gene-modified MSCs were superior to unmodified cells at strengthening host repair responses to radiation stress as well as presenting increased serum CXCL12 levels and decreased serum IL-1α levels. Furthermore, the number of crypt cells that were positive for phosphorylated Akt at Ser473 and phosphorylated Erk1/2 at Thr202/Thr204 increased following treatment with mouse cxcl12 gene-modified MSCs. Thus, cxcl12 gene-modified MSCs confer radioresistance to the intestinal epithelium.

Bowel Radiation Injury: Complexity of the Pathophysiology and Promises of Cell and Tissue Engineering

Ionizing radiation is effective to treat malignant pelvic cancers, but the toxicity to surrounding healthy tissue remains a substantial limitation. Early and late side effects not only limit the escalation of the radiation dose to the tumor but may also be life-threatening in some patients. Numerous preclinical studies determined specific mechanisms induced after irradiation in different compartments of the intestine. This review outlines the complexity of the pathogenesis, highlighting the roles of the epithelial barrier in the vascular network, and the inflammatory microenvironment, which together lead to chronic fibrosis. Despite the large number of pharmacological molecules available, the studies presented in this review provide encouraging proof of concept regarding the use of mesenchymal stromal cell (MSC) therapy to treat radiation-induced intestinal damage. The therapeutic efficacy of MSCs has been demonstrated in animal models and in patients, but an enormous number of cells and multiple injections are needed due to their poor engraftment capacity. Moreover, it has been observed that although MSCs have pleiotropic effects, some intestinal compartments are less restored after a high dose of irradiation. Future research should seek to optimize the efficacy of the injected cells, particularly with regard to extending their life span in the irradiated tissue. Moreover, improving the host microenvironment, combining MSCs with other specific regenerative cells, or introducing new tissue engineering strategies could be tested as methods to treat the severe side effects of pelvic radiotherapy.

A biomaterial-assisted mesenchymal stromal cell therapy alleviates colonic radiation-induced damage

Healthy tissues surrounding abdomino-pelvic tumours can be impaired by radiotherapy, leading to chronic gastrointestinal complications with substantial mortality. Adipose-derived Mesenchymal Stromal Cells (Ad-MSCs) represent a promising strategy to reduce intestinal lesions. However, systemic administration of Ad-MSCs results in low cell engraftment within the injured tissue. Biomaterials, able to encapsulate and withstand Ad-MSCs, can overcome these limitations. A silanized hydroxypropylmethyl cellulose (Si-HPMC) hydrogel has been designed and characterized for injectable cell delivery using the operative catheter of a colonoscope. We demonstrated that hydrogel loaded-Ad-MSCs were viable, able to secrete trophic factors and responsive to the inflammatory environment. In a rat model of radiation-induced severe colonic damage, Ad-MSC + Si-HPMC improve colonic epithelial structure and hyperpermeability compared with Ad-MSCs injected intravenously or locally. This therapeutic benefit is associated with greater engraftment of Si-HPMC-embedded Ad-MSCs in the irradiated colonic mucosa. Moreover, macrophage infiltration near the injection site was less pronounced when Ad-MSCs were embedded in the hydrogel. Si-HPMC induces modulation of chemoattractant secretion by Ad-MSCs that could contribute to the decrease in macrophage infiltrate. Si-HPMC is suitable for cell delivery by colonoscopy and induces protection of Ad-MSCs in the tissue potentiating their therapeutic effect and could be proposed to patients suffering from colon diseases.

Plerixafor Improves Primary Tumor Response and Reduces Metastases in Cervical Cancer Treated with Radio-Chemotherapy

Purpose: There is an important need to improve the effectiveness of radio-chemotherapy (RTCT) for cervical cancer. The CXCL12/CXCR4 pathway can influence RT response by recruiting normal myeloid cells to the tumor microenvironment that in turn can exert radioprotective effects, and may promote metastases. The objective of this study was to explore the efficacy and toxicity of combining RTCT with CXCL12/CXCR4 inhibition in cervical cancer.Experimental Design: CXCR4 expression was measured in 115 patients with cervical cancer. Two primary orthotopic cervical cancer xenografts (OCICx) with different levels of CXCR4 expression were treated with RT (30 Gy: 15 daily fractions) and weekly cisplatin (4 mg/kg), with or without the CXCR4 inhibitor Plerixafor (5 mg/kg/day). The endpoints were tumor growth delay and lymph node metastases. Acute intestinal toxicity was assessed using a crypt cell assay.Results: There was a fivefold variation in CXCR4 mRNA expression in the patient samples, and good correlation between the expression in patients and in the xenografts. The combination of RTCT and Plerixafor produced substantial tumor growth delay and reduced lymph node metastases compared with RTCT alone in both of the xenograft models. There was a trend toward reduced acute intestinal toxicity with the addition of Plerixafor to RTCT. There were no changes in normal organ morphology to suggest increased late toxicity.Conclusions: This study demonstrates that the addition of Plerixafor to standard RTCT improves primary tumor response and reduces metastases in cervical cancer with no increase in toxicity. This combination warrants further investigation in phase I/II clinical trials. Clin Cancer Res; 23(5); 1242-9. ©2016 AACR.

Intraperitoneal injection (IP), Intravenous injection (IV) or anal injection (AI)? Best way for mesenchymal stem cells transplantation for colitis

Stem cell transplantation showed promising results in IBD management. However, the therapeutic impacts of cell delivery route that is critical for clinical translation are currently poorly understood. Here, three different MSCs delivery routes: intraperitoneal (IP), intravenous (IV), and anal injection (AI) were compared on DSS-induced colitic mice model. The overall therapeutic factors, MSCs migration and targeting as well as local immunomodulatory cytokines and FoxP3⁺ cells infiltration were analyzed. Colitis showed varying degrees of alleviation after three ways of MSCs transplantation, and the IP injection showed the highest survival rate of 87.5% and displayed the less weight loss and quick weight gain. The fecal occult blood test on the day 3 also showed nearly complete absence of occult blood in IP group. The fluorescence imaging disclosed higher intensity of engrafted cells in inflamed colon and the corresponding mesentery lymph nodes (MLNs) in IP and AI groups than the IV group. Real time-PCR and ELISA also demonstrate lower TNF-α and higher IL-10, TSG-6 levels in IP group. The immunohistochemistry indicated higher repair proliferation (Ki-67) and more FoxP3⁺ cells accumulation of IP group. IP showed better colitis recovery and might be the optimum MSCs delivery route for the treatment of DSS-induced colitis.

Autologous bone marrow stromal cell transplantation as a treatment for acute radiation enteritis induced by a moderate dose of radiation in dogs

Radiation enteritis is one of the most common complications of cancer radiotherapy, and the development of new and effective measures for its prevention and treatment is of great importance. Adult bone marrow stromal stem cells (ABMSCs) are capable of self-renewal and exhibit low immunogenicity. In this study, we investigated ABMSC transplantation as a treatment for acute radiation enteritis. We developed a dog model of acute radiation enteritis using abdominal intensity-modulated radiation therapy in a single X-ray dose of 14 Gy. ABMSCs were cultured in vitro, identified via immunofluorescence and flow cytometry, and double labeled with CM-Dil and superparamagnetic iron oxide (SPIO) before transplantation, which took place 48 hours after abdominal irradiation in a single fraction. The dog model of acute radiation enteritis was transplanted with cultured ABMSCs labeled with CM-Dil and SPIO into the mesenteric artery through the femoral artery. Compared with untreated control groups, dogs treated with ABMSCs exhibited substantially longer survival time and improved relief of clinical symptoms. ABMSC transplantation induced the regeneration of the intestinal epithelium and the recovery of intestinal function. Furthermore, ABMSC transplantation resulted in elevated serum levels of the anti-inflammatory cytokine interleukin-11 (IL10) and intestinal radioprotective factors, such as keratinocyte growth factor, basic fibroblast growth factor-2, and platelet-derived growth factor-B while reducing the serum level of the inflammatory cytokine IL17. ABMSCs induced the regeneration of the intestinal epithelium and regulated the secretion of serum cytokines and the expression of radioprotective proteins and thus could be beneficial in the development of novel and effective mitigators of and protectors against acute radiation enteritis.

Radioresistance of granulation tissue-derived cells from skin wounds combined with total body irradiation

Combined radiation and wound injury (CRWI) occurs following nuclear explosions and accidents, radiological or nuclear terrorism, and radiation therapy combined with surgery. CRWI is complicated and more difficult to heal than single injuries. Stem cell‑based therapy is a promising treatment strategy for CRWI, however, sourcing stem cells remains a challenge. In the present study, the granulation tissue-derived cells (GTCs) from the skin wounds (SWs) of CRWI mice (C‑GTCs) demonstrated a higher radioresistance to the damage caused by combined injury, and were easier to isolate and harvest when compared with bone marrow‑derived mesenchymal stromal cells (BMSCs). Furthermore, the C-GTCs exhibited similar stem cell-associated properties, such as self-renewal and multilineage differentiation capacity, when compared with neonatal dermal stromal cells (DSCs) and GTCs from unirradiated SWs. Granulation tissue, which is easy to access, may present as an optimal autologous source of stem/progenitor cells for therapeutic applications in CRWI.

Safety and efficacy of allogeneic adipose tissue-derived mesenchymal stem cells for treatment of dogs with inflammatory bowel disease: Clinical and laboratory outcomes

Mesenchymal stem cells (MSCs) have shown immunomodulatory and anti-inflammatory effects in experimental colitis, and promising clinical results have been obtained in humans with Crohn's disease and ulcerative colitis. The aim of this study was to determine the safety and feasibility of adipose tissue-derived MSC (ASC) therapy in dogs with inflammatory bowel disease (IBD). Eleven dogs with confirmed IBD received one ASC intravascular (IV) infusion (2 × 10(6) cells/kg bodyweight). The outcome measures were clinical response based on percentage reduction of the validated Clinical Inflammatory Bowel Disease Activity Index (CIBDAI) and Canine Chronic Enteropathy Clinical Activity Index (CCECAI), as well as normalisation of C-reactive protein (CRP), albumin, folate and cobalamin serum concentrations at day 42 post-treatment. The Wilcoxon test was used to compare variables before and after treatment. No acute reaction to ASC infusion and no side effects were reported during follow-up in any dog. Six weeks post-treatment, the CIBDAI and CCECAI decreased significantly and albumin, cobalamin and folate concentrations increased substantially. Differences in CRP concentrations pre- and post-treatment were not significant (P = 0.050). Clinical remission (defined by a reduction of initial CIBDAI and CCECAI >75%) occurred in 9/11 dogs at day 42. The two remaining dogs showed a partial response with reduction percentages of 69.2% and 71.4%. In conclusion, a single IV infusion of allogeneic ASCs was well tolerated and appeared to produce clinical benefits in dogs with severe IBD.

The potential of mesenchymal stem cells in the management of radiation enteropathy

Although radiotherapy is effective in managing abdominal and pelvic malignant tumors, radiation enteropathy is still unavoidable. This disease severely affects the quality of life of cancer patients due to some refractory lesions, such as intestinal ischemia, mucositis, ulcer, necrosis or even perforation. Current drugs or prevailing therapies are committed to alleviating the symptoms induced by above lesions. But the efficacies achieved by these interventions are still not satisfactory, because the milieus for tissue regeneration are not distinctly improved. In recent years, regenerative therapy for radiation enteropathy by using mesenchymal stem cells is of public interests. Relevant results of preclinical and clinical studies suggest that this regenerative therapy will become an attractive tool in managing radiation enteropathy, because mesenchymal stem cells exhibit their pro-regenerative potentials for healing the injuries in both epithelium and endothelium, minimizing inflammation and protecting irradiated intestine against fibrogenesis through activating intrinsic repair actions. In spite of these encouraging results, whether mesenchymal stem cells promote tumor growth is still an issue of debate. On this basis, we will discuss the advances in anticancer therapy by using mesenchymal stem cells in this review after analyzing the pathogenesis of radiation enteropathy, introducing the advances in managing radiation enteropathy using regenerative therapy and exploring the putative actions by which mesenchymal stem cells repair intestinal injuries. At last, insights gained from the potential risks of mesenchymal stem cell-based therapy for radiation enteropathy patients may provide clinicians with an improved awareness in carrying out their studies.

Mesenchymal stromal cells and chronic inflammatory bowel disease

Recent experimental findings have shown the ability of mesenchymal stromal cells (MSCs) to home to damaged tissues and to produce paracrine factors with anti-inflammatory properties, potentially resulting in reduction of inflammation and functional recovery of the damaged tissues. Prompted by these intriguing properties and on the basis of encouraging preclinical data, MSCs are currently being studied in several immune-mediated disorders. Inflammatory bowel diseases (IBD) represent a setting in which MSCs-based therapy has been extensively investigated. Phase I and II studies have documented the safety and feasibility of MSCs. However, efficacy results have so far been conflicting. In this review, we will discuss the biologic rationale that makes MSCs a promising therapeutic tool for IBD, and analyze recent experimental and clinical findings, highlighting current limitations and future perspectives of MSCs-related immunotherapy for IBD.

Expression of Wnt and Notch signaling pathways in inflammatory bowel disease treated with mesenchymal stem cell transplantation: evaluation in a rat model

INTRODUCTION

The purpose of this study was to investigate the expression of Wnt and Notch signaling pathway-related genes in inflammatory bowel disease (IBD) treated with mesenchymal stem cell transplantation (MSCT).

METHODS

TNBS (2,4,6-trinitrobenzene sulfonic acid) was used to establish IBD in a rat model. Mesenchymal stem cells (MSCs) were transplanted via tail vein transfusion. Saline water was used in a control group. The expression of Wnt and Notch main signaling molecules was screened by gene chips and verified by quantitative reverse transcription-polymerase chain reaction in the IBD rat model on day 14 and day 28 after transplantation.

RESULTS

The IBD rat models were successfully established and MSCs were transplanted into those models. Genome-wide expression profile chips identified a total of 388 differentially expressive genes, of which 191 were upregulated and 197 were downregulated in the MSC-transplanted group in comparison with the IBD control group. Real-time quantitative polymerase chain reaction results showed that the level of Olfm4 mRNA expression in the IBD group (2.54±0.20) was significantly increased compared with the MSCT group (1.39±0.54) and the normal group (1.62±0.25) (P <0.05). The Wnt3a mRNA was more highly expressed in IBD rats (2.92±0.94) and decreased in MSCT rats (0.17±0.63, P <0.05). The expression of GSK-3β mRNA was decreased in the setting of inflammation (0.65±0.04 versus 1.00±0.01 in normal group, P <0.05) but returned to normal levels after MSCT (0.81±0.17). The expression of β-catenin was observed to increase in IBD tissues (1.76±0.44) compared with normal tissues (1.00±0.01, P <0.05), but no difference was found in the MSCT group (1.12±0.36). Wnt11 declined at 14 days and returned to normal levels at 28 days in the IBD group; in comparison, a significantly lower expression was found in MSCT rats. There were no differences in the expression of Fzd3, c-myc, TCF4, and Wnt5a in inflammation, but all of those genes declined after MSCT treatment.

CONCLUSIONS

The canonical Wnt and Notch signaling pathways are activated in IBD and may be suppressed by stem cell transplantation to differentiate into intestinal epithelium after MSCT. Moreover, the non-canonical Wnt signaling may be inhibited by canonical Wnt signaling in the setting of inflammation and may also be suppressed by MSCT.

HGF Gene Modification in Mesenchymal Stem Cells Reduces Radiation-Induced Intestinal Injury by Modulating Immunity

Background

Effective therapeutic strategies to address intestinal complications after radiation exposure are currently lacking. Mesenchymal stem cells (MSCs), which display the ability to repair the injured intestine, have been considered as delivery vehicles for repair genes. In this study, we evaluated the therapeutic effect of hepatocyte growth factor (HGF)-gene-modified MSCs on radiation-induced intestinal injury (RIII).

Methods

Female 6- to 8-week-old mice were radiated locally at the abdomen with a single 13-Gy dose of radiation and then treated with saline control, Ad-HGF or Ad-Null-modified MSCs therapy. The transient engraftment of human MSCs was detected via real-time PCR and immunostaining. The therapeutic effects of non- and HGF-modified MSCs were evaluated via FACS to determine the lymphocyte immunophenotypes; via ELISA to measure cytokine expression; via immunostaining to determine tight junction protein expression; via PCNA staining to examine intestinal epithelial cell proliferation; and via TUNEL staining to detect intestinal epithelial cell apoptosis.

Results

The histopathological recovery of the radiation-injured intestine was significantly enhanced following non- or HGF-modified MSCs treatment. Importantly, the radiation-induced immunophenotypic disorders of the mesenteric lymph nodes and Peyer’s patches were attenuated in both MSCs-treated groups. Treatment with HGF-modified MSCs reduced the expression and secretion of inflammatory cytokines, including tumor necrosis factor alpha (TNF-α) and interferon-gamma (IFN-γ), increased the expression of the anti-inflammatory cytokine IL-10 and the tight junction protein ZO-1, and promoted the proliferation and reduced the apoptosis of intestinal epithelial cells.

Conclusions

Treatment of RIII with HGF-gene-modified MSCs reduces local inflammation and promotes the recovery of small intestinal histopathology in a mouse model. These findings might provide an effective therapeutic strategy for RIII.

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.

Effects of cytokines and chemokines on migration of mesenchymal stem cells following spinal cord injury

We investigated the effects of cytokines and chemokines and their associated signaling pathways on mesenchymal stem cell migration after spinal cord injury, to determine their roles in the curative effects of mesenchymal stem cells. This study reviewed the effects of tumor necrosis factor-α, vascular endothelial growth factor, hepatocyte growth factor, platelet-derived growth factor, basic fibroblast growth factor, insulin like growth factor-1, stromal cell-derived factor and monocyte chemoattractant protein-1, 3 during mesenchymal stem cell migration to damaged sites, and analyzed the signal transduction pathways involved in their effects on mesenchymal stem cell migration. The results confirmed that phosphatidylinositol 3-kinase/serine/threonine protein kinases and nuclear factor-κB play crucial roles in the migration of mesenchymal stem cells induced by cytokines and chemokines.

Bone marrow-derived mesenchymal stem cell transplantation ameliorates oxidative stress and restores intestinal mucosal permeability in chemically induced colitis in mice

BACKGROUND

Ulcerative colitis (UC) can be viewed as an autoimmune disease. Bone marrow-derived mesenchymal stem cells (MSCs) with its regenerative, cellular multi-lineage and immunomodulatory abilities can influence the repair of damaged tissues in UC. This study investigated the effects of MSCs transplantation on the mice intestinal barrier in response to oxidative stress injury.

METHODS

Colitis was induced by daily consecutive administration of 5% dextran sulfate sodium (DSS) solution for 7 days. Male murine MSCs were isolated and transplanted into female mice via injection in the tail vein. Serum and colon specimens were collected at 12 h, 24 h, 3 d, 7 d and 14 d after injection. Serum levels of D-lactate (D-LAC), diamine oxidase (DAO), colonic levels of malondialdehyde (MDA) and superoxide dismutase (SOD) were quantified. The SRY protein of the male sex determinant gene expression and E-cadherin were also ascertained intracellularly.

RESULTS

Three days after receiving male MSCs transplantation, SRY protein expression was detected. The quantity increased on successive days. Serum levels of D-LAC and DAO, colonic MDA and SOD normalized in a shorter time period compared to controls (p<0.05). Not surprisingly, histological regeneration of tissue and E-cadherin expression in the colon of MSCs transplanted mice also occurred in a shorter time period than controls.

CONCLUSIONS

Transplanted MSCs restored mucosal permeability, and minimized oxidative stress related injury.

In vivo tracking and fate of intra-articularly injected superparamagnetic iron oxide particle-labeled multipotent stromal cells in an ovine model of osteoarthritis

In this study, superparamagnetic iron oxide (SPIO) particle-labeled mesenchymal stromal cells (MSCs) were injected intra-articularly into osteoarthritic knee joints. Their fate and distribution were evaluated using magnetic resonance imaging (MRI) and macroscopic and histologic postmortem examination. Osteoarthritis was induced in 12 sheep by bilateral meniscectomy. After 6 weeks, one knee joint received 10 × 10(6) SPIO-labeled MSCs (Molday Ion Rhodamine B). Contralateral knees received a control injection of a) PBS, b) SPIO in PBS, c) 10 × 10(6) nonvital SPIO-labeled MSCs in PBS, or d) no injection. MR images were acquired immediately after injection and 1, 4, 8, and 12 weeks thereafter using a 0.5-T unit and a T2* sequence. Signal intensity of synovial fluid and synovial lining was assessed semiquantitatively using a scoring system. Viable SPIO-labeled MSCs produced a strong hypointense signal in the synovial fluid immediately after injection, but normal signal intensity of the synovial fluid was observed 1 week later. Synovial lining maintained its hypointensity throughout the study period. Nonvital SPIO-labeled MSCs induced hypointense signals of the synovial fluid; synovial lining appeared weak and inconsistently hypointense in the following weeks. Pure SPIO produced a strong hyperintense signal in the synovial fluid at the time of injection only. Histologically, in all knee joints receiving viable SPIO-labeled MSCs, SPIO particles were detected (Prussian blue) within the synovial lining, dorsal fat pad, and neomeniscus tissue, but not in osteochondral samples. Few SPIO particles were detected in joints injected with nonvital SPIO-labeled MSCs. Immunohistologically, no increased cell death (TUNEL) was observed in the area of detected SPIO particles, but we did observe potential chondrogenic cell differentiation (Safranin O or S100β). We conclude that viable SPIO-labeled MSCs remain detectable within the joint for 12 weeks and attach themselves to some but not all diseased joint structures.

Defining the optimal window for cranial transplantation of human induced pluripotent stem cell-derived cells to ameliorate radiation-induced cognitive impairment

Past preclinical studies have demonstrated the capability of using human stem cell transplantation in the irradiated brain to ameliorate radiation-induced cognitive dysfunction. Intrahippocampal transplantation of human embryonic stem cells and human neural stem cells (hNSCs) was found to functionally restore cognition in rats 1 and 4 months after cranial irradiation. To optimize the potential therapeutic benefits of human stem cell transplantation, we have further defined optimal transplantation windows for maximizing cognitive benefits after irradiation and used induced pluripotent stem cell-derived hNSCs (iPSC-hNSCs) that may eventually help minimize graft rejection in the host brain. For these studies, animals given an acute head-only dose of 10 Gy were grafted with iPSC-hNSCs at 2 days, 2 weeks, or 4 weeks following irradiation. Animals receiving stem cell grafts showed improved hippocampal spatial memory and contextual fear-conditioning performance compared with irradiated sham-surgery controls when analyzed 1 month after transplantation surgery. Importantly, superior performance was evident when stem cell grafting was delayed by 4 weeks following irradiation compared with animals grafted at earlier times. Analysis of the 4-week cohort showed that the surviving grafted cells migrated throughout the CA1 and CA3 subfields of the host hippocampus and differentiated into neuronal (∼39%) and astroglial (∼14%) subtypes. Furthermore, radiation-induced inflammation was significantly attenuated across multiple hippocampal subfields in animals receiving iPSC-hNSCs at 4 weeks after irradiation. These studies expand our prior findings to demonstrate that protracted stem cell grafting provides improved cognitive benefits following irradiation that are associated with reduced neuroinflammation.

Factors affecting directional migration of bone marrow mesenchymal stem cells to the injured spinal cord

Microtubule-associated protein 1B plays an important role in axon guidance and neuronal migration. In the present study, we sought to discover the mechanisms underlying microtubule-associated protein 1B mediation of axon guidance and neuronal migration. We exposed bone marrow mesenchymal stem cells to okadaic acid or N-acetyl-D-erythro-sphingosine (an inhibitor and stimulator, respectively, of protein phosphatase 2A) for 24 hours. The expression of the phosphorylated form of type I microtubule-associated protein 1B in the cells was greater after exposure to okadaic acid and lower after N-acetyl-D-erythro-sphingosine. We then injected the bone marrow mesenchymal stem cells through the ear vein into rabbit models of spinal cord contusion. The migration of bone marrow mesenchymal stem cells towards the injured spinal cord was poorer in cells exposed to okadaic acid- and N-acetyl-D-erythro-sphingosine than in non-treated bone marrow mesenchymal stem cells. Finally, we blocked phosphatidylinositol 3-kinase (PI3K) and extracellular signal-regulated kinase 1/2 (ERK1/2) pathways in rabbit bone marrow mesenchymal stem cells using the inhibitors LY294002 and U0126, respectively. LY294002 resulted in an elevated expression of phosphorylated type I microtubule-associated protein 1B, whereas U0126 caused a reduction in expression. The present data indicate that PI3K and ERK1/2 in bone marrow mesenchymal stem cells modulate the phosphorylation of microtubule-associated protein 1B via a cross-signaling network, and affect the migratory efficiency of bone marrow mesenchymal stem cells towards injured spinal cord.

Application of human bone marrow-derived mesenchymal stem cells in the treatment of radiation-induced Gastrointestinal syndrome

Nuclear accidents and terrorism present a serious threat for mass casualty. Accidental or intended radiation exposure leads to radiation-induced gastrointestinal (GI) syndrome. However, currently there are no approved medical countermeasures for GI syndrome. Thus, developing novel treatments for GI syndrome is urgent. Mesenchymal stem cells (MSCs) derived from bone marrow are a subset of multipotent adult somatic stem cells that have the ability to undergo self-renewal, proliferation and pluripotent differentiation. MSCs have advantages over other stem cells; they can be easily isolated from patients or donors, readily expanded ex vivo, and they possess reparative and immunomodulatory properties. Moreover, MSCs have been shown to be powerful tools in gene therapy and can be effectively transduced with vectors containing therapeutic genes. Therefore, the therapeutic potential of MSCs has been brought into the spotlight for the clinical treatment of GI syndrome. In this review, we discuss the possible role of MSCs in radiation-induced GI syndrome.

Stem cell therapies for the treatment of radiation-induced normal tissue side effects

SIGNIFICANCE

Targeted irradiation is an effective cancer therapy but damage inflicted to normal tissues surrounding the tumor may cause severe complications. While certain pharmacologic strategies can temper the adverse effects of irradiation, stem cell therapies provide unique opportunities for restoring functionality to the irradiated tissue bed.

RECENT ADVANCES

Preclinical studies presented in this review provide encouraging proof of concept regarding the therapeutic potential of stem cells for treating the adverse side effects associated with radiotherapy in different organs. Early-stage clinical data for radiation-induced lung, bone, and skin complications are promising and highlight the importance of selecting the appropriate stem cell type to stimulate tissue regeneration.

CRITICAL ISSUES

While therapeutic efficacy has been demonstrated in a variety of animal models and human trials, a range of additional concerns regarding stem cell transplantation for ameliorating radiation-induced normal tissue sequelae remain. Safety issues regarding teratoma formation, disease progression, and genomic stability along with technical issues impacting disease targeting, immunorejection, and clinical scale-up are factors bearing on the eventual translation of stem cell therapies into routine clinical practice.

FUTURE DIRECTIONS

Follow-up studies will need to identify the best possible stem cell types for the treatment of early and late radiation-induced normal tissue injury. Additional work should seek to optimize cellular dosing regimes, identify the best routes of administration, elucidate optimal transplantation windows for introducing cells into more receptive host tissues, and improve immune tolerance for longer-term engrafted cell survival into the irradiated microenvironment.

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.

HB-EGF augments the ability of mesenchymal stem cells to attenuate intestinal injury

BACKGROUND

We have previously demonstrated that heparin-binding EGF-like growth factor (HB-EGF) and mesenchymal stem cell (MSC) administration protect the intestines from ischemia/reperfusion (I/R) injury in vivo, with amniotic fluid-derived MSC (AF-MSC) being more efficacious than bone marrow-derived MSC (BM-MSC). The goal of the current study was to determine whether the protective effects of HB-EGF were from direct effects on MSC or via alternative mechanisms.

METHODS

Murine MSC were transfected with an HB-EGF plasmid or control plasmid by electroporation. Mice were subjected to segmental intestinal I/R injury and received either BM-MSC or AF-MSC either with or without exogenous HB-EGF, or BM-MSC or AF-MSC that endogenously over-expressed HB-EGF. MSC engraftment, intestinal histologic injury, and intestinal permeability were quantified.

RESULTS

There was increased MSC engraftment into injured compared to uninjured intestine. HB-EGF increased AF-MSC engraftment into injured intestine. Administration of HB-EGF and MSC improved intestinal histology and intestinal permeability after I/R injury, with AF-MSC being most efficacious. The effect of HB-EGF on MSC was similar when the growth factor was administered exogenously, or when it was overexpressed endogenously.

CONCLUSIONS

The effect of HB-EGF on AF-MSC was similar with both exogenous administration and endogenous overexpression of the growth factor, implying that HB-EGF has a direct effect on AF-MSC. This information may assist in guiding potential future AF-MSC-based therapies for patients at risk of intestinal ischemic injuries.

Identification and characterization of circulating variants of CXCL12 from human plasma: effects on chemotaxis and mobilization of hematopoietic stem and progenitor cells

Mobilization of hematopoietic stem and progenitor cells (HPCs) is induced by treatment with granulocyte-colony stimulating factor, chemotherapy, or irradiation. We observed that these treatments are accompanied by a release of chemotactic activity into the blood. This plasma activity is derived from the bone marrow, liver, and spleen and acts on HPCs via the chemokine receptor CXCR4. A human blood peptide library was used to characterize CXCR4-activating compounds. We identified CXCL12[22-88] and N-terminally truncated variants CXCL12[24-88], CXCL12[25-88], CXCL12[27-88], and CXCL12[29-88]. Only CXCL12[22-88] could effectively bind to CXCR4 and induce intracellular calcium flux and chemotactic migration of HPCs. CXCL12[25-88] and CXCL12[27-88] revealed neither agonistic nor antagonistic activities in vitro, whereas CXCL12[29-88] inhibited CXCL12[22-88]-induced chemotactic migration. Since binding to glycosaminoglycans (GAG) modulates the function of CXCL12, binding to heparin was analyzed. Surface plasmon resonance kinetic analysis showed that N-terminal truncation of Arg22-Pro23 increased the dissociation constant KD by one log10 stage ([22-88]: KD: 5.4 ± 2.6 μM; [24-88]: KD: 54 ± 22.4 μM). Further truncation of the N-terminus decreased the KD ([25-88] KD: 30 ± 4.8 μM; [27-88] KD: 23 ± 1.6 μM; [29-88] KD: 19 ± 5.4 μM), indicating increasing competition for heparin binding. Systemic in vivo application of CXCL12[22-88] as well as CXCL12[27-88] or CXCL12[29-88] induced a significant mobilization of HPCs in mice. Our findings indicate that plasma-derived CXCL12 variants may contribute to the regulation of HPC mobilization by modulating the binding of CXCL12[22-88] to GAGs rather than blocking the CXCR4 receptor and, therefore, may have a contributing role in HPC mobilization.

Intestinal stem cells and celiac disease

Stem cells (SCs) are the key to tissue genesis and regeneration. Given their central role in homeostasis, dysfunctions of the SC compartment play a pivotal role in the development of cancers, degenerative disorders, chronic inflammatory pathologies and organ failure. The gastrointestinal tract is constantly exposed to harsh mechanical and chemical conditions and most of the epithelial cells are replaced every 3 to 5 d. According to the so-called Unitarian hypothesis, this renewal is driven by a common intestinal stem cell (ISC) residing within the crypt base at the origin of the crypt-to-villus hierarchical migratory pattern. Celiac disease (CD) can be defined as a chronic immune-mediated disease that is triggered and maintained by dietary proteins (gluten) in genetically predisposed individuals. Many advances have been achieved over the last years in understanding of the pathogenic interactions among genetic, immunological and environmental factors in CD, with a particular emphasis on intestinal barrier and gut microbiota. Conversely, little is known about ISC modulation and deregulation in active celiac disease and upon a gluten-free diet. Nonetheless, bone marrow-derived SC transplantation has become an option for celiac patients with complicated or refractory disease. This manuscript summarizes the “state of the art” regarding CD and ISCs, their niche and potential role in the development and treatment of the disease.

Use of mesenchymal stem cells (MSC) in chronic inflammatory fistulizing and fibrotic diseases: a comprehensive review

Mesenchymal stem cells (MSC), multipotent adult stem cells, feature the potential to regenerate tissue damage and, in parallel, inhibit inflammation and fibrosis. MSC can be safely transplanted in autologous and allogeneic ways as they are non-immunogenic, and consequently represent a therapeutic option for refractory connective tissue diseases, fibrosing diseases like scleroderma and fistulizing colitis like in Crohn's disease. Actually, there are more than 200 registered clinical trial sites for evaluating MSC therapy, and 22 are on autoimmune diseases. In irradiation-induced colitis, MSC accelerate functional recovery of the intestine and dampen the systemic inflammatory response. In order to provide rescue therapy for accidentally over-irradiated prostate cancer patients who underwent radiotherapy, allogeneic bone marrow-derived MSC from family donors were intravenously infused to three patients with refractory and fistulizing colitis resembling fistulizing Crohn's disease. Systemic MSC therapy of refractory irradiation-induced colitis was safe and effective on pain, diarrhoea, hemorrhage, inflammation and fistulization accompanied by modulation of the lymphocyte subsets towards an increase of T regulatory cells and a decrease of activated effector T cells. The current data indicate that MSC represent a promising alternative strategy in the treatment of various immune-mediated diseases. Encouraging results have already been obtained from clinical trials in Crohn's disease and SLE as well as from case series in systemic sclerosis. MSC represent a safe therapeutic measure for patients who suffer from chronic and fistulizing colitis. These findings are instructional for the management of refractory inflammatory bowel diseases that are characterized by similar clinical and immunopathological features.

Ionizing irradiation induces acute haematopoietic syndrome and gastrointestinal syndrome independently in mice

The role of bone marrow (BM) and BM-derived cells in radiation-induced acute gastrointestinal (GI) syndrome is controversial. Here we use bone marrow transplantation (BMT), total body irradiation (TBI) and abdominal irradiation (ABI) models to demonstrate a very limited, if any, role of BM-derived cells in acute GI injury and recovery. Compared with WT BM recipients, mice receiving BM from radiation-resistant PUMA KO mice show no protection from crypt and villus injury or recovery after 15 or 12 Gy TBI, but have a significant survival benefit at 12 Gy TBI. PUMA KO BM significantly protects donor-derived pan-intestinal haematopoietic (CD45+) and endothelial (CD105+) cells after IR. We further show that PUMA KO BM fails to enhance animal survival or crypt regeneration in radiosensitive p21 KO-recipient mice. These findings clearly separate the effects of radiation on the intestinal epithelium from those on the BM and endothelial cells in dose-dependent acute radiation toxicity.

Bone marrow transplantation helps restore the intestinal mucosal barrier after total body irradiation in mice

Bone marrow transplantation (BMT) substantially improves 10-day survival after total body irradiation (TBI), consistent with an effect on intestinal radiation death. Total body irradiation, in addition to injuring the intestinal epithelium, also perturbs the mucosal immune system, the largest immune system in the body. This study focused on how transplanted bone marrow cells (BMCs) help restore mucosal immune cell populations after sublethal TBI (8.0 Gy). We further evaluated whether transplanted BMCs: (a) home to sites of radiation injury using green fluorescent protein labeled bone marrow; and (b) contribute to restoring the mucosal barrier in vivo. As expected, BMT accelerated recovery of peripheral blood (PB) cells. In the intestine, BMT was associated with significant early recovery of mucosal granulocytes (P = 0.005). Bone marrow transplantation did not affect mucosal macrophages or lymphocyte populations at early time points, but enhanced the recovery of these cells from day 14 onward (P = 0.03). Bone marrow transplantation also attenuated radiation-induced increase of intestinal CXCL1 and restored IL-10 levels (P = 0.001). Most importantly, BMT inhibited the post-radiation increase in intestinal permeability after 10 Gy TBI (P = 0.02) and modulated the expression of tight junction proteins (P = 0.01-0.05). Green fluorescent protein-positive leukocytes were observed both in intestinal tissue and in PB. These findings strongly suggest that BMT, in addition to enhancing general hematopoietic and immune system recovery, helps restore the intestinal immune system and enhances intestinal mucosal barrier function. These findings may be important in the development and understanding of strategies to alleviate or treat intestinal radiation toxicity.

Gastro-intestinal autoimmunity: preclinical experiences and successful therapy of fistulizing bowel diseases and gut Graft versus host disease by mesenchymal stromal cells

Mesenchymal stromal cells (MSC) are multipotent adult stem cells with the potential to regenerate tissue damage and inhibit inflammation and fibrosis in parallel. As they are non-immunogenic, MSC can be safely auto- and allotransplanted and consequently represent a therapeutic option for refractory connective tissue diseases and fistulizing colitis like Crohn's disease. Actually, there are more than 200 registered clinical trial sites for evaluating MSC therapy, 22 are on autoimmune diseases and 27 are actually recruiting bowel disease' patients. More than 1,500 patients with bowel diseases like Crohn's disease were treated in clinical trials by local as well as systemic MSC therapy. Phase I and II trials on fistula documented the feasibility and safety of MSC therapy, and a significant superiority compared to fibrin glue in fistulizing bowel diseases was demonstrated. Autologous as well as allogeneic use of Bone marrow as well as of adipose tissue-derived MSC are feasible. In refractory Graft versus host disease, especially in refractory gut Graft versus host diseases, encouraging results were reported using MSC. Systemic MSC therapy of refractory irradiation-induced colitis was safe and effective on pain, diarrhea, hemorrhage, inflammation and fistulization accompanied by modulation of the lymphocyte subsets toward an increase in T regulatory cells and a decrease in activated effector T cells. Mesenchymal stem cells represent a safe therapy for patients with refractory inflammatory bowel diseases.

Berberine Reduces Rat Intestinal Tight Junction Injury Induced by Ischemia–Reperfusion Associated with the Suppression of Inducible Nitric Oxide Synthesis

Berberine (BBR) has been shown to attenuate the deleterious effects of ischemia/reperfusion (I/R) injury in the brain. We evaluated the effects of BBR on intestinal tight junction (TJ) changes during mesenteric I/R. I/R was induced in rats by the occlusion of the superior mesenteric artery and reperfusion. The rats were randomized into four groups: control, BBR, I/R, and I/R + BBR. Intestinal permeability was determined by the lactulose/mannitol test. The ileum and colon were harvested to assess mucosal injury and inducible nitric oxide synthase activity. The TJ ultrastructure was studied by transmission electron microscopy. The expressions and locations of the TJ proteins, occludin and ZO-1, in the epithelium were investigated by immunofluorescence microscopy. We also used Western blot analysis to detect the distribution of TJ proteins in lipid raft fractions. Our results suggest that I/R-induced intestinal TJ dysfunction can be improved by BBR, thereby demonstrating the therapeutic potential of BBR for intestinal I/R.

New insights for pelvic radiation disease treatment: Multipotent stromal cell is a promise mainstay treatment for the restoration of abdominopelvic severe chronic damages induced by radiotherapy

Radiotherapy may induce irreversible damage on healthy tissues surrounding the tumor. It has been reported that the majority of patients receiving pelvic radiation therapy show early or late tissue reactions of graded severity as radiotherapy affects not only the targeted tumor cells but also the surrounding healthy tissues. The late adverse effects of pelvic radiotherapy concern 5% to 10% of them, which could be life threatening. However, a clear medical consensus concerning the clinical management of such healthy tissue sequelae does not exist. Although no pharmacologic interventions have yet been proven to efficiently mitigate radiotherapy severe side effects, few preclinical researches show the potential of combined and sequential pharmacological treatments to prevent the onset of tissue damage. Our group has demonstrated in preclinical animal models that systemic mesenchymal stromal cell (MSC) injection is a promising approach for the medical management of gastrointestinal disorder after irradiation. We have shown that MSCs migrate to damaged tissues and restore gut functions after irradiation. We carefully studied side effects of stem cell injection for further application in patients. We have shown that clinical status of four patients suffering from severe pelvic side effects resulting from an over-dosage was improved following MSC injection in a compationnal situation.

Analysis of chemotactic molecules in bone marrow-derived mesenchymal stem cells and the skin: Ccl27-Ccr10 axis as a basis for targeting to cutaneous tissues

BACKGROUND AIMS

Adult stem cells produce a plethora of extracellular matrix molecules and have a high potential as cell-based therapeutics for connective tissue disorders of the skin. However, the primary challenge of the stem cell-based approach is associated with the inefficient homing of systemically infused stem cells to the skin.

METHODS

We examined chemotactic mechanisms that govern directional migration of mesenchymal stem cells (MSCs) into the skin by conducting a comprehensive expression analysis of chemotactic molecules in MSCs and defined cutaneous tissues from normal and hereditary epidermolysis bullosa (EB)-affected skin.

RESULTS

Analysis of chemokine receptors in short-term and long-term MSC cultures showed tissue culture-dependent expression of several receptors. Assessment of epidermis-derived and dermis-derived chemokines showed that most chemotactic signals that originate from the skin preferentially recruit different sets of leukocytes rather than MSCs. Analysis of the chemotactic molecules derived from EB-affected non-blistered skin showed only minor changes in expression of selected chemokines and receptors. Nevertheless, the data allowed us to define the Ccl27-Ccr10 chemotactic axis as the most potent for the recruitment of MSCs to the skin. Our in vivo analysis demonstrated that uniform expression of Ccr10 on MSCs and alteration of Ccl27 level in the skin enhance extravasation of stem cells from circulation and facilitate their migration within cutaneous tissue.

CONCLUSIONS

Collectively, our study provides a comprehensive analysis of chemotactic signals in normal and EB-affected skin and proof-of-concept data demonstrating that alteration of the chemotactic pathways can enhance skin homing of the therapeutic stem cells.

Bone-marrow mesenchymal stem cells reduce rat intestinal ischemia-reperfusion injury, ZO-1 downregulation and tight junction disruption via a TNF-α-regulated mechanism

AIM: To investigate the effect of bone-marrow mesenchymal stem cells (BM MSCs) on the intestinal mucosa barrier in ischemia/reperfusion (I/R) injury.

METHODS: BM MSCs were isolated from male Sprague-Dawley rats by density gradient centrifugation, cultured, and analyzed by flow cytometry. I/R injury was induced by occlusion of the superior mesenteric artery for 30 min. Rats were treated with saline, BM MSCs (via intramucosal injection) or tumor necrosis factor (TNF)-α blocking antibodies (via the tail vein). I/R injury was assessed using transmission electron microscopy, hematoxylin and eosin (HE) staining, immunohistochemistry, western blotting and enzyme linked immunosorbent assay.

RESULTS: Intestinal permeability increased, tight junctions (TJs) were disrupted, and zona occludens 1 (ZO-1) was downregulated after I/R injury. BM MSCs reduced intestinal mucosal barrier destruction, ZO-1 downregulation, and TJ disruption. The morphological abnormalities after intestinal I/R injury positively correlated with serum TNF-α levels. Administration of anti-TNF-α IgG or anti-TNF-α receptor 1 antibodies attenuated the intestinal ultrastructural changes, ZO-1 downregulation, and TJ disruption.

CONCLUSION: Altered serum TNF-α levels play an important role in the ability of BM MSCs to protect against intestinal I/R injury.

Synergistic effects of HB-EGF and mesenchymal stem cells in a murine model of intestinal ischemia/reperfusion injury

BACKGROUND

We have previously demonstrated that heparin-binding EGF-like growth factor (HB-EGF) administration protects the intestines from ischemia/reperfusion (I/R) injury in vivo. We have also shown that HB-EGF promotes mesenchymal stem cell (MSC) proliferation and migration in vitro. The goals of the current study were to examine the effects of HB-EGF and both bone marrow (BM)- and amniotic fluid (AF)-derived MSC on intestinal I/R injury in vivo.

MATERIALS AND METHODS

MSC were isolated from pan-EGFP mice, expanded, and purified. Pluripotency was confirmed by induced differentiation. Mice were subjected to terminal ileum I/R and received either: (1) no therapy; (2) HB-EGF; (3) BM-MSC; (4) HB-EGF+BM-MSC; (5) AF-MSC; or (6) HB-EGF+AF-MSC. MSC engraftment, histologic injury, and intestinal permeability were quantified.

RESULTS

There was increased MSC engraftment into injured compared to uninjured intestine for all experimental groups, with significantly increased engraftment for AF-MSC+HB-EGF compared to AF-MSC alone. Administration of HB-EGF and MSC improved intestinal histology and intestinal permeability after I/R injury. The greatest improvement was with combined administration of HB-EGF+AF-MSC.

CONCLUSIONS

Both HB-EGF alone and MSC alone can protect the intestines from I/R injury, with synergistic efficacy occurring when HB-EGF and AF-MSC are administered together.

EphB2 isolates a human marrow stromal cell subpopulation with enhanced ability to contribute to the resident intestinal cellular pool

To identify human bone marrow stromal cell (BMSC) subsets with enhanced ability to engraft/contribute to the resident intestinal cellular pool, we transplanted clonally derived BMSCs into fetal sheep. Analysis at 75 d post-transplantation showed 2 of the 6 clones engrafting the intestine at 4- to 5-fold higher levels (5.03±0.089 and 5.04±0.15%, respectively) than the other clones (P<0.01), correlating with the percentage of donor-derived Musashi-1(+) (12.01-14.17 vs. 1.2-3.8%; P<0.01) or leucine-rich repeat-containing G-protein coupled receptor 5 (Lgr5)(+) cells within the intestinal stem cell (ISC) region. Phenotypic and transcriptome analysis determined that the clones with enhanced intestinal contribution expressed high levels of Ephrin type B receptor 2 (EphB2). Intestinal explants demonstrated proliferation of the engrafted cells and ability to generate crypt-like structures in vitro still expressing EphB2. Additional transplants based on BMSC EphB2 expression demonstrated that, at 7 d post-transplant, the EphB2(high) BMSCs engrafted in the ISC region at levels of 2.1 ± 0.2%, while control EphB2(low) BMSCs engrafted at 0.3 ± 0.1% (P<0.01). Therefore we identified a marker for isolating and culturing an expandable subpopulation of BMSCs with enhanced intestinal homing and contribution to the ISC region.

Mesenchymal stem cells overexpressing C-X-C chemokine receptor type 4 improve early liver regeneration of small-for-size liver grafts

Mesenchymal stem cell (MSC) therapy can prevent hepatic parenchymal cell loss and promote tissue repair. However, poor MSC engraftment is one of the primary barriers to the effectiveness of cell therapy because culture-expanded MSCs progressively down-regulate C-X-C chemokine receptor type 4 (CXCR4) expression and lose their ability to migrate toward a concentration gradient of stromal cell-derived factor 1a (SDF1a). In this study, we investigated whether a CXCR4-MSC infusion could protect hepatocytes and stimulate regeneration in 50% reduced size liver transplantation (RSLT). Rats that underwent 50% RSLT were randomly divided into 3 groups: a phosphate-buffered solution group (PBS), a green fluorescent protein (GFP)-MSC group, and a CXCR4-MSC group. Rats received 1 mL of PBS with or without a resuspension of GFP-MSCs or CXCR4-MSCs. The factors secreted by MSCs, the graft function, the apoptosis and proliferation of hepatocytes, the efficacy of MSC engraftment, and the expression of SDF1α, albumin (Alb), and cytokeratin 18 (CK18) in engrafted GFP-positive MSCs were assessed. A systemic infusion of GFP-MSCs led to a reduction of the release of liver injury biomarkers and apoptosis of hepatocytes; CXCR4 overexpression did not further reduce the liver injury. However, CXCR4 overexpression enhanced MSC engraftment in liver grafts, improved the effect on the proliferation of hepatocytes, and thus provided a significant 1-week survival benefit. SDF1α expression in grafts was elevated after transplanted CXCR4-MSCs were recruited to the remnant liver. However, engrafted MSCs did not express the markers of hepatocytes, including Alb and CK18, in vivo 168 hours after transplantation. CXCR4 overexpression enhanced the mobilization and engraftment of MSCs into small-for-size liver grafts, in which these cells promoted the early regeneration of the remnant liver not by direct differentiation but perhaps by a paracrine mechanism.

Use of mesenchymal stem cells (MSC) in chronic inflammatory fistulizing and fibrotic diseases: a comprehensive review

Mesenchymal stem cells (MSC), multipotent adult stem cells, feature the potential to regenerate tissue damage and, in parallel, inhibit inflammation and fibrosis. MSC can be safely transplanted in autologous and allogeneic ways as they are non-immunogenic, and consequently represent a therapeutic option for refractory connective tissue diseases, fibrosing diseases like scleroderma and fistulizing colitis like in Crohn's disease. Actually, there are more than 200 registered clinical trial sites for evaluating MSC therapy, and 22 are on autoimmune diseases. In irradiation-induced colitis, MSC accelerate functional recovery of the intestine and dampen the systemic inflammatory response. In order to provide rescue therapy for accidentally over-irradiated prostate cancer patients who underwent radiotherapy, allogeneic bone marrow-derived MSC from family donors were intravenously infused to three patients with refractory and fistulizing colitis resembling fistulizing Crohn's disease. Systemic MSC therapy of refractory irradiation-induced colitis was safe and effective on pain, diarrhoea, hemorrhage, inflammation and fistulization accompanied by modulation of the lymphocyte subsets towards an increase of T regulatory cells and a decrease of activated effector T cells. The current data indicate that MSC represent a promising alternative strategy in the treatment of various immune-mediated diseases. Encouraging results have already been obtained from clinical trials in Crohn's disease and SLE as well as from case series in systemic sclerosis. MSC represent a safe therapeutic measure for patients who suffer from chronic and fistulizing colitis. These findings are instructional for the management of refractory inflammatory bowel diseases that are characterized by similar clinical and immunopathological features.

Safety and efficacy of mesenchymal stromal cell therapy in autoimmune disorders

Mesenchymal stromal cells (MSCs) are being employed in clinical trials to facilitate engraftment and to treat steroid-resistant acute graft-versus-host disease after hematopoietic stem cell transplantation, as well as to repair tissue damage in inflammatory/degenerative disorders, in particular, in inflammatory bowel diseases (IBDs). When entering the clinical arena, a few potential risks of MSC therapy have to be taken into account: (i) immunogenicity of the cells, (ii) biosafety of medium components, (iii) risk of ectopic tissue formation, and (iv) potential in vitro transformation of the cells during expansion. This paper analyzes the main risks connected with the use of MSCs in cellular therapy approaches, and reports on some of the most intriguing findings on the use of MSCs in the context of regenerative medicine. Experimental studies in animal models and phase I/II clinical trials on the use of MSCs for the treatment of IBDs and other inflammatory/degenerative conditions are reviewed.

Mesenchymal Stromal Cell-Based Treatment of Jaw Osteoradionecrosis in Swine

Jaw osteoradionecrosis (ORN) is a common and serious complication of radiation therapy for head and neck cancers. Bone marrow mesenchymal stromal cells (BMMSCs) are multipotent postnatal stem cells and have been widely used in clinical therapies. In the present study, we generated the mandibular ORN model in swine using a combination of single-dose 25-Gy irradiation and tooth extraction. A typical ORN phenotype, including loss of bone regeneration capacity and collagen collapse with the obliteration of vessels, gradually appeared after irradiation. After autologous BMMSC transplantation, new bone and vessels were regenerated, and the advanced mandibular ORN was treated successfully. In summary, we developed a swine model of jaw ORN, and our results indicate that autologous BMMSC transplantation may be a promising therapeutic approach for ORN.

Heparin-binding epidermal growth factor-like growth factor protects mesenchymal stem cells

BACKGROUND

We have previously demonstrated that mesenchymal stem cell (MSC) administration protects the intestines from injury in a mouse model of intestinal ischemia/reperfusion injury. We have also shown that heparin-binding epidermal growth factor-like growth factor (HB-EGF) is a potent intestinal cytoprotective agent in vivo that can protect the intestines by way of its effects on stem cells. The goal of the present study was to examine the effects of HB-EGF on both amniotic fluid (AF)- and bone marrow (BM)-derived MSCs in vitro.

METHODS

MSCs were isolated from the AF and BM of pan-EGFP mice, grown in MSC-specific culture medium, and purified by sequential passages according to their adherence properties. Pluripotency was confirmed by induced differentiation. After incubation of MSCs with HB-EGF, proliferation was quantified using the CyQuant cell proliferation assay kit under normoxic and anoxic conditions. Chemotaxis was quantified using the CHEMICON QCM cell migration kit, and apoptosis was determined using caspase-3 immunohistochemistry after exposure of the MSCs to anoxic stress.

RESULTS

AF-MSCs and BM-MSCs showed significantly increased proliferation and migration in response to HB-EGF. HB-EGF significantly protected AF-MSCs and BM-MSCs from anoxia-induced apoptosis. The proliferative and anti-apoptotic effects of HB-EGF were even more pronounced in AF-MSCs than in BM-MSCs.

CONCLUSIONS

These results have demonstrated that HB-EGF acts as a mitogenic and chemotactic agent for MSCs that protects MSCs from injury. These findings could have important implications for future experiments designed to use MSCs to protect the intestines from injury.

Animal models and medical countermeasures development for radiation-induced lung damage: report from an NIAID Workshop

Since 9/11, there have been concerns that terrorists may detonate a radiological or nuclear device in an American city. Aside from several decorporation and blocking agents for use against internal radionuclide contamination, there are currently no medications within the Strategic National Stockpile that are approved to treat the immediate or delayed complications resulting from accidental exposure to radiation. Although the majority of research attention has focused on developing countermeasures that target the bone marrow and gastrointestinal tract, since they represent the most acutely radiosensitive organs, individuals who survive early radiation syndromes will likely suffer late effects in the months that follow. Of particular concern are the delayed effects seen in the lung that play a major role in late mortality seen in radiation-exposed patients and accident victims. To address these concerns, the National Institute of Allergy and Infectious Diseases convened a workshop to discuss pulmonary model development, mechanisms of radiation-induced lung injury, targets for medical countermeasures development, and end points to evaluate treatment efficacy. Other topics covered included guidance on the challenges of developing and licensing drugs and treatments specific to a radiation lung damage indication. This report reviews the data presented, as well as key points from the ensuing discussion.

Bone marrow stromal cell transplantation mitigates radiation-induced gastrointestinal syndrome in mice

Background

Nuclear accidents and terrorism presents a serious threat for mass casualty. While bone-marrow transplantation might mitigate hematopoietic syndrome, currently there are no approved medical countermeasures to alleviate radiation-induced gastrointestinal syndrome (RIGS), resulting from direct cytocidal effects on intestinal stem cells (ISC) and crypt stromal cells. We examined whether bone marrow-derived adherent stromal cell transplantation (BMSCT) could restitute irradiated intestinal stem cells niche and mitigate radiation-induced gastrointestinal syndrome.

Methodology/Principal Findings

Autologous bone marrow was cultured in mesenchymal basal medium and adherent cells were harvested for transplantation to C57Bl6 mice, 24 and 72 hours after lethal whole body irradiation (10.4 Gy) or abdominal irradiation (16–20 Gy) in a single fraction. Mesenchymal, endothelial and myeloid population were characterized by flow cytometry. Intestinal crypt regeneration and absorptive function was assessed by histopathology and xylose absorption assay, respectively. In contrast to 100% mortality in irradiated controls, BMSCT mitigated RIGS and rescued mice from radiation lethality after 18 Gy of abdominal irradiation or 10.4 Gy whole body irradiation with 100% survival (p<0.0007 and p<0.0009 respectively) beyond 25 days. Transplantation of enriched myeloid and non-myeloid fractions failed to improve survival. BMASCT induced ISC regeneration, restitution of the ISC niche and xylose absorption. Serum levels of intestinal radioprotective factors, such as, R-Spondin1, KGF, PDGF and FGF2, and anti-inflammatory cytokines were elevated, while inflammatory cytokines were down regulated.

Conclusion/Significance

Mitigation of lethal intestinal injury, following high doses of irradiation, can be achieved by intravenous transplantation of marrow-derived stromal cells, including mesenchymal, endothelial and macrophage cell population. BMASCT increases blood levels of intestinal growth factors and induces regeneration of the irradiated host ISC niche, thus providing a platform to discover potential radiation mitigators and protectors for acute radiation syndromes and chemo-radiation therapy of abdominal malignancies.