Transplanted mesenchymal stem cells accelerate glomerular healing in experimental glomerulonephritis

Therapeutic effects of human amniotic fluid-derived stem cells on renal interstitial fibrosis in a murine model of unilateral ureteral obstruction

Interstitial fibrosis is regarded as the main pathway for the progression of chronic kidney disease (CKD) and is often associated with severe renal dysfunction. Stem cell-based therapies may provide alternative approaches for the treatment of CKD. Human amniotic fluid-derived stem cells (hAFSCs) are a novel stem cell population, which exhibit both embryonic and mesenchymal stem cell characteristics. Herein, the present study investigated whether the transplantation of hAFSCs into renal tissues could improve renal interstitial fibrosis in a murine model of unilateral ureteral obstruction (UUO). We showed that hAFSCs provided a protective effect and alleviated interstitial fibrosis as reflected by an increase in microvascular density; additionally, hAFSCs treatment beneficially modulated protein levels of vascular endothelial growth factor (VEGF), hypoxia inducible factor-1α (HIF-1α) and transforming growth factor-β1 (TGF-β1). Therefore, we hypothesize that hAFSCs could represent an alternative, readily available source of stem cells that can be applied for the treatment of renal interstitial fibrosis.

Bone-marrow-derived mesenchymal stem cells for organ repair

Mesenchymal stem cells (MSCs) are prototypical adult stem cells with the capacity for self-renewal and differentiation with a broad tissue distribution. MSCs not only differentiate into types of cells of mesodermal lineage but also into endodermal and ectodermal lineages such as bone, fat, cartilage and cardiomyocytes, endothelial cells, lung epithelial cells, hepatocytes, neurons, and pancreatic islets. MSCs have been identified as an adherent, fibroblast-like population and can be isolated from different adult tissues, including bone marrow (BM), umbilical cord, skeletal muscle, and adipose tissue. MSCs secrete factors, including IL-6, M-CSF, IL-10, HGF, and PGE2, that promote tissue repair, stimulate proliferation and differentiation of endogenous tissue progenitors, and decrease inflammatory and immune reactions. In this paper, we focus on the role of BM-derived MSCs in organ repair.

The therapeutic potential of mesenchymal stem cell-derived extracellular vesicles

Extracellular vesicles (EVs), membrane vesicles that are secreted by a variety of mammalian cell types, have been shown to play an important role in intercellular communication. The contents of EVs, including proteins, microRNAs, and mRNAs, vary according to the cell type that secreted them. Accordingly, researchers have demonstrated that EVs derived from various cell types play different roles in biological phenomena. Considering the ubiquitous presence of mesenchymal stem cells (MSCs) in the body, MSC-derived EVs may take part in a wide range of events. In particular, MSCs have recently attracted much attention due to the therapeutic effects of their secretory factors. MSC-derived EVs may therefore provide novel therapeutic approaches. In this review, we first summarize the wide range of functions of EVs released from different cell types, emphasizing that EVs echo the phenotype of their parent cell. Then, we describe the various therapeutic effects of MSCs and pay particular attention to the significance of their paracrine effect. We then survey recent reports on MSC-derived EVs and consider the therapeutic potential of MSC-derived EVs. Finally, we discuss remaining issues that must be addressed before realizing the practical application of MSC-derived EVs, and we provide some suggestions for enhancing their therapeutic efficiency.

Mesenchymal stem cells ameliorate podocyte injury and proteinuria in a type 1 diabetic nephropathy rat model

Mesenchymal stem cells (MSC) attenuate albuminuria and preserve normal renal histology in diabetic mice. However, the effects of MSC on glomerular podocyte injury remain uncertain. The aim of this study was to evaluate the effects of MSC on podocyte injury in streptozotocin (STZ)-induced diabetic rats. Thirty days after diabetes induction by STZ injection (65 mg/kg, intraperitoneally) in Sprague-Dawley rats, the diabetic rats received medium or 2 × 10(6) enhanced green fluorescent protein-labeled MSC via the renal artery. In vivo tracking of MSC was followed by immunofluorescence analysis. Diabetes-related physical and biochemical parameters were measured on day 60 after the MSC infusion. The expression of podocyte markers (nephrin and podocin), podocyte survival factors (VEGF and BMP-7), and the ultrastructural pathology of podocytes were also assessed. MSC were only detected in the glomeruli from the left kidney receiving MSC infusion. Compared with medium-treated diabetic rats, rats treated with MSC showed a suppressed increase in kidney weight, kidney to body weight index, creatinine clearance rate, and urinary albumin to creatinine ratio; however, the treatment had no effect on blood glucose or body weight levels. Furthermore, the MSC treatment reduced the loss of podocytes, effacement of foot processes, widening of foot processes, thickening of glomerular basal membrane (GBM), and loss of glomerular nephrin and podocin. Most important, MSC-injected kidneys expressed higher levels of BMP-7 but not of VEGF. Our results clearly demonstrated that intra-arterial administration of MSC prevented the development of albuminuria as well as any damage to or loss of podocytes, though there was no improvement in blood sugar levels. The protective effects of MSC may be mediated in part by increasing BMP-7 secretion.

Human umbilical cord blood-derived mesenchymal stem cells prevent diabetic renal injury through paracrine action

AIMS

The present study examined renoprotective effect of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSC) in diabetes. NRK-52E cells were utilized to determine the paracrine effect of hUCB-MSC.

METHODS

hUCB was harvested with the mother's consent. MSC obtained from the hUCB were injected through the tail vein. Growth arrested and synchronized NRK-52E cells were stimulated with transforming growth factor-β1 (TGF-β1) in the presence of hUCB-MSC conditioned media.

RESULTS

At 4 weeks after the streptozotocin (STZ) injection, diabetic rats showed significantly increased urinary protein excretion, renal and glomerular hypertrophy, fractional mesangial area, renal expression of TGF-β1 and α-smooth muscle actin, and collagen accumulation but decreased renal E-cadherin and bone morphogenic protein-7 expression, confirming diabetic renal injury. hUCB-MSC effectively prevented diabetic renal injury except renal and glomerular hypertrophy without a significant effect on blood glucose. CM-DiI-labeled hUCB-MSC and immunostaining of PKcs, a human nuclei antigen, confirmed a few engraftment of hUCB-MSC in diabetic kidneys. hUCB-MSC conditioned media inhibited TGF-β1-induced extracellular matrix upregulation and epithelial-to-mesenchymal transition in NRK-52E cells in a concentration-dependent manner.

CONCLUSIONS

These results demonstrate the renoprotective effect of hUCB-MSC in STZ-induced diabetic rats possibly through secretion of humoral factors and suggest hUCB-MSC as a possible treatment modality for diabetic renal injury.

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.

The comparison of interleukin 6-associated immunosuppressive effects of human ESCs, fetal-type MSCs, and adult-type MSCs

BACKGROUND

Although human embryonic stem cells (ESCs) and mesenchymal stem cells (MSCs) from various sources display immunomodulatory effects, direct comparisons among these classes of stem cells have not been reported.

METHODS

Peripheral blood mononuclear cell suppression assays and carboxyfluorescein diacetate succinimidyl ester assays were used to assess the immunosuppressive effects of stem cells. Gene expression was measured using DNA microarrays. Enzyme-linked immunosorbent assays were used to determine interleukin (IL)-6 levels.

RESULTS

We found that fetal-type MSCs proliferated significantly faster than adult-type MSCs. Compared with ESCs grown on feeder cells, ESCs grown in feeder cell-free conditions exhibited decreased immunosuppressive effects. The suppressive effects of ESCs were significantly stronger than those of MSCs, and the suppressive effects of fetal-type MSCs were significantly stronger than those of adult-type MSCs at each tested dose level. Analysis of gene expression by microarray and MetaCore pathway mapping revealed changes in eight different immune response pathways; we observed that IL-6 gene expression was highly significantly involved in all eight pathways. Significantly higher IL-6 elevation ratios (IL-6after:IL-6before) were found in ESCs compared with fetal-type MSCs, and these were also found in fetal-type MSCs compared with adult-type MSCs. Furthermore, IL-6 levels were found to correlate with cell dosages of MSCs and the suppressive effects.

CONCLUSIONS

The ease of obtaining fetal-type MSCs and their rapid proliferation make these cells ideal candidates for cell-based therapies, especially for diseases associated with immune responses, given the immunosuppressive effects of these cells. IL-6 might play an important role in the immunosuppressive effects of various stem cells.

MSC and Tumors: Homing, Differentiation, and Secretion Influence Therapeutic Potential

: Mesenchymal stromal/stem cells (MSC) are adult multipotent progenitors with fibroblast-like morphology able to differentiate into adipocytic, osteogenic, chondrogenic, and myogenic lineages. Due to these properties, MSC have been studied and introduced as therapeutics in regenerative medicine. Preliminary studies have also shown a possible involvement of MSC as precursors of cellular elements within tumor microenvironments, in particular tumor-associated fibroblasts (TAF). Among a number of different possible origins, TAF may originate from a pool of circulating progenitors from bone marrow or adipose tissue-derived MSC. There is growing evidence to corroborate that cells immunophenotypically defined as MSC are able to reside as TAF influencing the tumor microenvironment in a potentially bi-phasic and obscure manner: either promoting or inhibiting growth depending on tumor context and MSC sources. Here we focus on relationships between the tumor microenvironment, cancer cells, and MSC, analyzing their diverse ability to influence neoplastic development. Associated activities include MSC homing driven by the secretion of various mediators, differentiation towards TAF phenotypes, and reciprocal interactions with the tumor cells. These are reviewed here with the aim of understanding the biological functions of MSC that can be exploited for innovative cancer therapy.

[New approaches in progressive kidney diseases]

Renal fibrosis, i.e. the replacement of functional tissue with scar tissue, represents the pathological correlate for chronic kidney disease (CKD). A great number of renal diseases lead to CKD and thereby to renal fibrosis. Therefore, renal fibrosis represents an excellent treatment option for patients with CKD. Here we discuss the problems with the preclinical identification and testing of potential factors and therapeutic approaches for renal fibrosis as well as obstacles in the translation of these results to clinical practice. We present the preclinical evidence for the role of novel molecules involved in renal fibrosis, e.g. platelet-derived growth factors (PDGF), C5a or peroxisome proliferator-activated receptor-α (PPAR-α).

Mesenchymal stem cells ameliorate postpyelonephritic renal scarring in rats

OBJECTIVE

To evaluate the efficiency of mesenchymal stem cells in ameliorating renal scarring in a rat pyelonephritis model.

METHODS

Three groups each, including 8 Sprague-Dawley rats were formed: Group 1 = sham operated (4 were given mesenchymal stem cells); group 2 = pyelonephritis induced by Escherichia coli; and group 3 = pyelonephritis and mesenchymal stem cells. Rats not given mesenchymal stem cells in group 1 and 4 rats in groups 2 and 3 were sacrificed on the eighth day for evaluation of inflammation, and the remaining rats were sacrificed at the sixth week to determine renal scarring along with migration of mesenchymal stem cells to renal tubules and differentiation to tubular cells expressing aquaporin-1.

RESULTS

Rats in group 3 had lower scores of both acute (8th day) and chronic (6th week) histopathological alterations compared with rats in group 2. By contrast, although rats in group 3 were shown to have mesenchymal stem cells expressing aquaporin-1 in their renal tubules, these cells were not detected in kidney tissue of mesenchymal stem cells-treated sham rats.

CONCLUSION

These results indicate that mesenchymal stem cells migrated to renal tissues and ameliorated renal scarring in this rat model of pyelonephritis.

Canine mesenchymal stem cells are effectively labeled with silica nanoparticles and unambiguously visualized in highly autofluorescent tissues

Background

Development of a method for long-term labeling of cells is critical to elucidate transplanted cell fate and migration as well as the contribution to tissue regeneration. Silica nanoparticles have been recently developed and demonstrated to be biocompatible with a high labeling capacity. Thus, our study was designed to assess the suitability of silica nanoparticles for labeling canine mesenchymal stem cells (MSCs) and the fluorescence afficiency in highly autofluorescent tissue.

Results

We examined the effect of silica nanoparticle labeling on stem cell morphology, viability and differentiation as compared with those of unlabeled control cells. After 4 h of incubation with silica nanoparticles, they were internalized by canine MSCs without a change in the morphology of cells compared with that of control cells. The viability and proliferation of MSCs labeled with silica nanoparticles were evaluated by a WST-1 assay and trypan blue exclusion. No effects on cell viability were observed, and the proliferation of canine MSCs was not inhibited during culture with silica nanoparticles. Furthermore, adipogenic and osteogenic differentiation of silica nanoparticle-labeled canine MSCs was at a similar level compared with that of unlabeled cells, indicating that silica nanoparticle labeling did not alter the differentiation capacity of canine MSCs. Silica nanoparticle-labeled canine MSCs were injected into the kidneys of BALB/c mice after celiotomy, and then the mice were sacrificed after 2 or 3 weeks. The localization of injected MSCs was closely examined in highly autofluorescent renal tissues. Histologically, canine MSCs were uniformly and completely labeled with silica nanoparticles, and were unambiguously imaged in histological sections.

Conclusions

The results of the current study showed that silica nanoparticles are useful as an effective labeling marker for MSCs, which can elucidate the distribution and fate of transplanted MSCs.

The alleviation of acute and chronic kidney injury by human Wharton's jelly-derived mesenchymal stromal cells triggered by ischemia-reperfusion injury via an endocrine mechanism

BACKGROUND AIMS

The effects of human Wharton's jelly-derived mesenchymal stromal cells (WJ-MSC) on acute and chronic kidney injury induced by ischemia-reperfusion injury (IRI) were assessed.

METHODS

WJ-MSC were injected intravenously immediately after solitary kidney ischemia for 45 min. Cells were labeled with 5-bromo-2'deoxy-uridine (BrdU) for tracing in vivo. At 48 h post-IRI, serum creatinine and blood urea nitrogen (BUN) were measured. Tubular cell proliferation and apoptosis as well as activation of the Akt signal were identified by immunostaining. Real-time polymerase chain reaction (PCR) was employed to determine gene expression of inflammation-related cytokines and hepatocyte growth factor (HGF). Levels of human HGF were assayed by enzyme-linked immunosorbant assay (ELISA). Twenty-two weeks later, renal fibrosis was assessed by Masson's tri-chrome staining, collagen content and α-smooth muscle actin (α-SMA) staining.

RESULTS

There was no sign of labeled cells residing in the damaged kidney. Acute renal dysfunction elicited by IRI was considerably improved by WJ-MSC, in parallel with a stronger proliferative response and less apoptotic events. Additionally, phosphoAkt staining in injured tubular cells was substantially intensified. Cell treatment also caused a remarkable up-regulation of kidney interleukin (IL)-10, heme oxygenase (HO)-1 and HGF expression. Human HGF was detected in cell supernatants and the serum of cell-infused rats. Moreover, IRI-initiated fibrosis was abrogated by cell therapy, coincident with function amelioration.

CONCLUSIONS

WJ-MSC alleviate acute kidney injury, thereby rescuing the ensuing fibrotic lesions in an endocrine manner. The Akt signal in impaired tubular cells is reinforced by WJ-MSC, facilitating cell resistance to apoptosis and cell proliferation. HGF, either delivered or induced by WJ-MSC, is an important contributor.

A population of selected renal cells augments renal function and extends survival in the ZSF1 model of progressive diabetic nephropathy

New treatment paradigms that slow or reverse progression of chronic kidney disease (CKD) are needed to relieve significant patient and healthcare burdens. We have shown that a population of selected renal cells (SRCs) stabilized disease progression in a mass reduction model of CKD. Here, we further define the cellular composition of SRCs and apply this novel therapeutic approach to the ZSF1 rat, a model of severe progressive nephropathy secondary to diabetes, obesity, dyslipidemia, and hypertension. Injection of syngeneic SRCs into the ZSF1 renal cortex elicited a regenerative response that significantly improved survival and stabilized disease progression to renal structure and function beyond 1 year posttreatment. Functional improvements included normalization of multiple nephron structures and functions including glomerular filtration, tubular protein handling, electrolyte balance, and the ability to concentrate urine. Improvements to blood pressure, including reduced levels of circulating renin, were also observed. These functional improvements following SRC treatment were accompanied by significant reductions in glomerular sclerosis, tubular degeneration, and interstitial inflammation and fibrosis. Collectively, these data support the utility of a novel renal cell-based approach for slowing renal disease progression associated with diabetic nephropathy in the setting of metabolic syndrome, one of the most common causes of end-stage renal disease.

Response of VEGF to activation of viral receptors and TNFα in human mesangial cells

Vascular endothelial growth factor (VEGF) plays an important role in glomerular homeostasis as well as in the pathogenesis of kidney diseases as glomerulonephritis (GN) and diabetic nephropathy. Mesangial cells (MC), which are an integral part of the functional glomerular filtration barrier in that providing structural support, can behave like inflammatory cells and produce mediators as chemokines and growth factors; they are known to express viral receptors, with TLR3 having been attributed relevance in viral disease-associated GN. Experiments were performed on human MC in cell culture. Stimulation experiments were performed with poly (I:C) and hepatitis C RNA from patients with hepatitis C infection. We hereby show a TLR3-mediated upregulation of VEGF and its receptor subtype 2 (VEGF-R2) in human MC upon activation of viral receptors by poly (I:C) and hepatitis C virus. The increase in VEGF expression levels is further enhanced by tumor necrosis factor alpha (TNFα) which also induces the cytokines IL-6 and IL-8 as well as the chemokines MCP-1 and RANTES. These effects are potentiated by preincubation of MC with poly (I:C), just as the induction of the viral receptors TLR3, RIG-1, and MDA5 themselves. Moreover, MCP-1 itself is able to significantly increase mesangial VEGF expression. Therefore, with VEGF and VEGF-R2 being induced upon viral receptor activation in human MC, a novel role of TLR3 in mediating glomerular damage in virally induced or aggravated GN is inferred. TNFα and MCP-1 are seemingly important in amplifying VEGF effects in the setting of virally induced inflammation, with TNFα being also able to induce other mediators of glomerular pathology in GN.

Genetic modification of mesenchymal stem cells to overexpress CXCR4 and CXCR7 does not improve the homing and therapeutic potentials of these cells in experimental acute kidney injury

The therapeutic potential of bone marrow mesenchymal stem cells (MSCs) in kidney failure has been examined in some studies. However, recent findings indicate that after transplantation, these cells home to kidneys at very low levels. Interaction of stromal derived factor-1 (SDF-1) with its receptor, CXCR4, is of pivotal importance in migration and homing. Recently, CXCR7 has also been recognized as another SDF-1 receptor that interacts with CXCR4 and modulates its functions. In this study, CXCR4 and CXCR7 were separately and simultaneously overexpressed in BALB/c bone marrow MSCs by using a lentiviral vector system and the homing and renoprotective potentials of these cells were evaluated in a mouse model of cisplatin-induced acute kidney injury. Using flow cytometry, immunohistochemistry, and real-time PCR methods for detection of GFP-labeled MSCs, we found that although considerably entrapped in lungs, native MSCs home very rarely to kidneys and bone marrow and this rate cannot be significantly affected by CXCR4 and/or CXCR7 upregulation. Transplantation of neither native nor genetically engineered MSCs ameliorated kidney failure. We concluded that overexpression of CXCR4 and CXCR7 receptors in murine MSCs cannot improve the homing and therapeutic potentials of these cells and it can be due to severe chromosomal abnormalities that these cells bear during ex vivo expansion.

Systemic administration of a novel human umbilical cord mesenchymal stem cells population accelerates the resolution of acute liver injury

BACKGROUND

Hepatocytes and stem cells transplantation may be an alternative to liver transplantation in acute or chronic liver disease. We aimed to evaluate the therapeutic potential of mesenchymal stem cells from human umbilical cord (UCMSCs), a readily available source of mesenchymal stem cells, in the CCl4-induced acute liver injury model.

METHODS

Mesenchymal stem cells profile was analyzed by flow cytometry. In order to evaluate the capability of our UCMSCs to differentiate in hepatocytes, cells were seeded on three different supports, untreated plastic support, MatrigelTM and human liver acellular matrix. Cells were analyzed by immunocitochemistry for alpha-fetoprotein and albumin expression, qPCR for hepatocyte markers gene expression, Periodic Acid-Schiff staining for glycogen storage, ELISA for albumin detection and colorimetric assay for urea secretion.To assess the effects of undifferentiated UCMSCs in hepatic regeneration after an acute liver injury, we transplanted them via tail vein in mice injected intraperitoneally with a single dose of CCl4. Livers were analyzed by histological evaluation for damage quantification, immunostaining for Kupffer and stellate cells/liver myofibroblasts activation and for UCMSCs homing. Pro- and anti-inflammatory cytokines gene expression was evaluated by qPCR analysis and antioxidant enzyme activity was measured by catalase quantification.Data were analyzed by Mann-Whitney U-test, Kruskal-Wallis test and Cuzick's test followed by Bonferroni correction for multiple comparisons.

RESULTS

We have standardized the isolation procedure to obtain a cell population with hepatogenic properties prior to in vivo transplantation. When subjected to hepatogenic differentiation on untreated plastic support, UCMSCs differentiated in hepatocyte-like cells as demonstrated by their morphology, progressive up-regulation of mature hepatocyte markers, glycogen storage, albumin and urea secretion. However, cells seeded on 3D-supports showed a minor or negligible differentiation capacity.UCMSCs-transplanted mice showed a more rapid damage resolution, as shown by histological analysis, with a lower inflammation level and an increased catalase activity compared to CCl4-treated mice.

CONCLUSIONS

Our findings show that UCMSCs can be reliably isolated, have hepatogenic properties and following systemic administration are able to accelerate the resolution of an acute liver injury without any differentiation and manipulation. These features make UCMSCs strong candidates for future application in regenerative medicine for human acute liver disease.

Mesenchymal stromal cells in renal ischemia/reperfusion injury

Ischemia/reperfusion (I/R) injury is an inevitable consequence of organ transplantation and a major determinant of patient and graft survival in kidney transplantation. Renal I/R injury can lead to fibrosis and graft failure. Although the exact sequence of events in the pathophysiology of I/R injury remains unknown, the role of inflammation has become increasingly clear. In this perspective, mesenchymal stromal cells (MSCs) are under extensive investigation as potential therapy for I/R injury, since MSCs are able to exert immune regulatory and reparative effects. Various preclinical studies indicate the beneficial effects of MSCs in ameliorating renal injury and accelerating tissue repair. These versatile cells have been shown to migrate to sites of injury and to enhance repair by paracrine mechanisms instead of by differentiating and replacing the injured cells. The first phase I studies of MSCs in human renal I/R injury and kidney transplantation have been started, and results are awaited soon. In this review, preliminary results and opportunities of MSCs in human renal I/R injury are summarized. We might be heading towards a cell-based paradigm shift in the treatment of renal I/R injury.

Human embryonic mesenchymal stem cell-derived conditioned medium rescues kidney function in rats with established chronic kidney disease

Chronic kidney disease (CKD) is a major health care problem, affecting more than 35% of the elderly population worldwide. New interventions to slow or prevent disease progression are urgently needed. Beneficial effects of mesenchymal stem cells (MSC) have been described, however it is unclear whether the MSCs themselves or their secretome is required. We hypothesized that MSC-derived conditioned medium (CM) reduces progression of CKD and studied functional and structural effects in a rat model of established CKD.

CKD was induced by 5/6 nephrectomy (SNX) combined with L-NNA and 6% NaCl diet in Lewis rats. Six weeks after SNX, CKD rats received either 50 µg CM or 50 µg non-CM (NCM) twice daily intravenously for four consecutive days. Six weeks after treatment CM administration was functionally effective: glomerular filtration rate (inulin clearance) and effective renal plasma flow (PAH clearance) were significantly higher in CM vs. NCM-treatment. Systolic blood pressure was lower in CM compared to NCM. Proteinuria tended to be lower after CM. Tubular and glomerular damage were reduced and more glomerular endothelial cells were found after CM. DNA damage repair was increased after CM. MSC-CM derived exosomes, tested in the same experimental setting, showed no protective effect on the kidney. In a rat model of established CKD, we demonstrated that administration of MSC-CM has a long-lasting therapeutic rescue function shown by decreased progression of CKD and reduced hypertension and glomerular injury.

Stem cell therapy: a novel & futuristic treatment modality for disaster injuries

Stem cell therapy hold the potential to meet the demand for transplant cells/tissues needed for treating damages resulting from both natural and man-made disasters. Pluripotency makes embryonic stem cells and induced pluripotent stem cells ideal for use, but their teratogenic character is a major hindrance. Therapeutic benefits of bone marrow transplantation are well known but characterizing the potentialities of haematopoietic and mesenchymal cells is essential. Haematopoietic stem cells (HSCs) have been used for treating both haematopoietic and non-haematopoietic disorders. Ease of isolation, in vitro expansion, and hypoimmunogenecity have brought mesenchymal stem cells (MSCs) into limelight. Though differentiation of MSCs into tissue-specific cells has been reported, differentiation-independent mechanisms seem to play a more significant role in tissue repair which need to be addressed further. The safety and feasibility of MSCs have been demonstrated in clinical trials, and their use in combination with HSC for radiation injury treatment seems to have extended benefit. Therefore, using stem cells for treatment of disaster injuries along with the conventional medical practice would likely accelerate the repair process and improve the quality of life of the victim.

Isogenic mesenchymal stem cells transplantation improves a rat model of chronic aristolochic acid nephropathy via upregulation of hepatic growth factor and downregulation of transforming growth factor β1

Chronic aristolochic acid (AA) nephropathy (CAAN) caused by intake of AA-containing herbs is difficult to treat. We evaluated the therapeutic effect of bone marrow (BM) mesenchymal stem cells (MSCs) on a rat model of CAAN. Female Wistar rats were fed with decoction of Caulis Aristolochia manshuriensis by intragastric administration. MSCs were prepared from BM of male Wistar rats and injected into female CAAN rats through tail vein. Body weight, renal function, and urinary excretion of these CAAN rats were monitored before killing at the end of the 20th week. Blood, urine, and tissue samples were collected from experimental (MSC and non-MSC) and normal control groups. All animals developed renal fibrosis after 12 weeks of intake of AA-containing decoction. Fibrosis in the MSC groups was significantly reduced as examined with light and electron microscopy. Blood urea nitrogen, serum creatinine, and urine protein levels were significantly reduced and hemoglobin levels were improved in the MSC group as compared with the non-MSC group (p < 0.01). The expression of TGF-β1 mRNA and protein was reduced but hepatic growth factor (HGF) was increased in the MSC group compared with the non-MSC group, but still higher than the normal control level as measured by immunochemical, RT-PCR, and western blotting assays (p < 0.01). The renal fibrosis of CAAN could be protected by isogenic MSC transplantation, probably via upregulation of HGF and downregulation of TGF-β1.

Same or not the same? Comparison of adipose tissue-derived versus bone marrow-derived mesenchymal stem and stromal cells

Mesenchymal stem/stromal cells (MSCs) comprise a heterogeneous population of cells with multilineage differentiation potential, the ability to modulate oxidative stress, and secrete various cytokines and growth factors that can have immunomodulatory, angiogenic, anti-inflammatory and anti-apoptotic effects. Recent data indicate that these paracrine factors may play a key role in MSC-mediated effects in modulating various acute and chronic pathological conditions. MSCs are found in virtually all organs of the body. Bone marrow-derived MSCs (BM-MSCs) were discovered first, and the bone marrow was considered the main source of MSCs for clinical application. Subsequently, MSCs have been isolated from various other sources with the adipose tissue, serving as one of the alternatives to bone marrow. Adipose tissue-derived MSCs (ASCs) can be more easily isolated; this approach is safer, and also, considerably larger amounts of ASCs can be obtained compared with the bone marrow. ASCs and BM-MSCs share many biological characteristics; however, there are some differences in their immunophenotype, differentiation potential, transcriptome, proteome, and immunomodulatory activity. Some of these differences may represent specific features of BM-MSCs and ASCs, while others are suggestive of the inherent heterogeneity of both BM-MSC and ASC populations. Still other differences may simply be related to different isolation and culture protocols. Most importantly, despite the minor differences between these MSC populations, ASCs seem to be as effective as BM-MSCs in clinical application, and, in some cases, may be better suited than BM-MSCs. In this review, we will examine in detail the ontology, biology, preclinical, and clinical application of BM-MSCs versus ASCs.

Adipose-derived stem cells improve renal function in a mouse model of IgA nephropathy

T-cell dysregulation plays an important role in the pathogenesis of immunoglobulin A nephropathy (IgAN). Adipose-derived stem cells (ASCs) have been reported to be able to prevent tissue damage through immune-modulating effects. To evaluate the effects of ASCs in high IgA ddY (HIGA) mice, ASCs were isolated from HIGA mice with different stages of IgAN before and after disease onset. ASCs were injected at a dose of 5×10(6) cells/kg body weight through the tail vein every 2 weeks for 3 months. Although the administered ASCs were rarely detected in the glomeruli, 24-h proteinuria was markedly decreased in all ASC-treated groups. Although glomerular deposition of IgA was not significantly different among groups, mesangial proliferation and glomerulosclerosis were dramatically decreased in most ASC treatment groups. In addition, levels of fibrotic and inflammatory molecules were markedly decreased by ASC treatment. Interestingly, ASC therapy significantly decreased Th1 cytokine activity in the kidney and caused a shift to Th2 responses in spleen T-cells as determined by FACS analysis. Furthermore, conditioned media from ASCs abrogated aggregated IgA-induced Th1 cytokine production in cultured HIGA mesangial cells. These results suggest that the beneficial effects of ASC treatment in IgAN occur via paracrine mechanisms that modulate the Th1/Th2 cytokine balance. ASCs are therefore a promising new therapeutic agent for the treatment of IgAN.

Interaction between adipose tissue-derived mesenchymal stem cells and regulatory T-cells

Mesenchymal stem cells (MSCs) exhibit immunosuppressive capabilities, which have evoked interest in their application as cell therapy in transplant patients. So far it has been unclear whether allogeneic MSCs and host regulatory T-cells (Tregs) functionally influence each other. We investigated the interaction between both cell types using perirenal adipose tissue-derived MSCs (ASCs) from kidney donors and Tregs from blood bank donors or kidney recipients 6 months after transplantation. The immunomodulatory capacity of ASCs was not prejudiced by both Tregs from healthy donors and Tregs from graft recipients, indicating that ASCs were not targeted by the inhibitory effects of Tregs and vice versa. In addition, Tregs supported ASC function, as they did not alter the secretion of IFN-γ by immune cells and hence contributed to ASC activation and efficiency. ASCs exerted their suppressive role by expressing IDO, reducing levels of TNF-α, and by inducing the production of IL-10 in effector cells and Tregs. In conclusion, this study presents evidence that donor ASCs and acceptor Tregs do not impair each other's function and therefore encourages the use of MSC therapy for the prevention of graft rejection in solid organ transplantation.

Repairing the chronic damaged kidney: the role of regenerative medicine

The increasing number of patients who suffer from chronic kidney diseases combined with the organ shortage have directed the attention of researchers to new alternatives in the fields of regenerative medicine including cell-based therapies and tissue bioengineering. This review of renal regenerative medicine addresses the mechanisms of action by stem cells to regenerate or repair chronically damaged renal tissue, alternative routes for their delivery, the role of biomaterials in tissue engineering, and the potential therapeutic effects of combining cell therapy with biomaterials. Despite the promise of ongoing work for therapy of chronic renal failure, caution is required as a large gap still exists between scientific knowledge and clinical translation for safe, effective stem cell-based therapies.

Characterization of bone-marrow-derived rat mesenchymal stem cells depending on donor age

It is generally accepted that autologous transfers, as non-immunogenic, constitute the safest approach in cellular transplantations. However, this attitude is often associated with the need for isolation and extracorporeal propagation of cells derived from aged patients. Thus the knowledge about relationship between aging and the properties of MSCs (mesenchymal stem cells) is crucial in developing new clinical strategies. The aim of this study was to perform complex comparison of MSC derived from young and aged individuals, which included phenotype, proliferating rate, osteogenic and adipogenic potential and secretory activity. Evaluated populations were isolated from bone marrow of 3-month-old and 24-month-old rats. There was no significant difference in membrane antigen expression and PDT (population doubling time). Additionally, the adipogenic and osteogenic potential did not vary between studied populations. The reaction of MSCs to either mitogen [bFGF (basic fibroblas t growth factor)] or oxidative stress (H2O2) in vitro displayed a very similar pattern in both analysed populations. There was no difference in TGFβ1 (transforming growth factor β1) and VEGF (vascular endothelial growth factor) secretion measured by ELISA test and gene expression evaluated by real-time PCR. However, the expression of the gene for IL-1α (interleukin-1α) was 8-fold lower in oMSC (MSC isolated from old rats). These results indicate that aging individuals can be considered as candidates for autologous transplantation of bone-marrow-derived MSCs.

Human adipose tissue-derived mesenchymal stem cells protect kidneys from cisplatin nephrotoxicity in rats

Cisplatin has multiple cellular targets and modes of action that lead to nephrotoxicity. This suggests novel therapies that act at multiple cisplatin target sites may be effective. We tested whether human adipose tissue-derived mesenchymal stem cells (Ad-MSCs) can affect multiple target sites and protect against cisplatin-induced kidney damage. Rats were divided into four groups: control, infused with Ad-MSCs, injected with cisplatin, and cisplatin followed by infusion of Ad-MSCs. Animal survival and renal function were decreased and histological damage was increased in cisplatin-treated rats at day 3. Infusion of Ad-MSCs ameliorated renal dysfunction and tissue injury caused by cisplatin, leading to increased survival. Apoptotic cell death in the kidney was significantly reduced by infusion of Ad-MSCs. Activation of p53, JNK, and ERK and the expression of inflammation-related molecules were also decreased in the kidney that received Ad-MSCs. Very few Ad-MSCs were detected in the kidney. Conditioned medium from cultured Ad-MSCs had renal-protective functions in vivo and in vitro. Renal dysfunction and tissue damage caused by cisplatin were significantly reduced in rats treated with Ad-MSCs-conditioned medium. The viability of cultured renal proximal tubular cells exposed to cisplatin was also improved by coculture with Ad-MSCs or with conditioned medium. Release of proinflammatory mediators induced by cisplatin was inhibited in coculture with Ad-MSCs. Our results show that human Ad-MSCs exert a paracrine-protective effect on cisplatin nephrotoxicity at multiple target sites and suggest that human Ad-MSCs might be a new therapeutic approach for patients with acute kidney injury.

[Lung development and mesenchymal stem cells]

The survival of extremely premature newborns has increased because of improvements in perinatal care. These infants however, are at high risk for chronic lung disease of prematurity or bronchopulmonary dysplasia (BPD). BPD, the most common complication in infants born before 28 weeks of gestation, is a multifactorial disease characterized by an arrest in alveolar development. Current preventive and curative therapies show limited efficacy. Cell-based therapies hold tremendous promise in regenerative medicine. Recent evidence suggests the therapeutic benefit of mesenchymal stem (or stromal) cells (MSC) in various diseases, including among others neurodegenerative, cardiovascular and respiratory disorders. Moreover, in an oxygen-induced BPD model, we and others recently demonstrated that bone marrow (BM) derived-MSCs efficiently prevent the arrest in lung development. In this review, we summarize the current knowledge regarding the therapeutic properties and mechanisms of action, specifically paracrine, of MSCs.

Exosomes and the kidney: prospects for diagnosis and therapy of renal diseases

Exosomes are 40-100 nm membrane vesicles secreted into the extracellular space by numerous cell types. These structures can be isolated from body fluids including urine and plasma. Exosomes contain proteins, mRNAs, miRNAs, and signaling molecules that reflect the physiological state of their cells of origin and consequently provide a rich source of potential biomarker molecules. Aside from diagnostic uses, exosome-mediated transfer of proteins, mRNAs, miRNAs, and signaling molecules offer the promise that they may be used for therapeutic purposes. In this review, we integrate new knowledge about exosomes from outside the field of nephrology with recent progress by renal researchers in order to provide a basis for speculation about how the study of exosomes may affect the fields of nephrology and renal physiology in the next few years.

Infusion of mesenchymal stem cells overexpressing GDNF ameliorates renal function in nephrotoxic serum nephritis

Nephrotoxic serum nephritis (NSN) is a well-established animal model of glomerulonephritis, a frequent clinical condition with a high mortality rate owing to the ineffectiveness of current therapies. Mesenchymal stem cells (MSCs) are adult stem cells with potential as novel therapies in regenerative medicine owing to the absence of allogenic rejection. Glial cell-derived neurotrophic factor (GDNF) acts as a morphogen in kidney development. The therapeutic effectiveness of bone marrow MSCs overexpressing GDNF (GDNF-MSCs) was evaluated in an NSN rat model. An adenoviral vector was used to transduce MSCs with GDNF and a green fluorescent protein reporter gene. Then, GDNF-MSCs were injected into NSN rats via the renal artery. The influence of GDNF on renal injury was assessed. The location of GDNF-MSCs in kidneys was detected using fluorescence microscopy, cells were counted, and kidney function was measured. Infusion of GNDF-MSCs enhanced the recovery of renal function in NSN rats. MSCs were detected in the kidney cortex after injection. Compared with control MSCs, GDNF-MSCs led to significantly better renal function and injury recovery in NSN rats. GDNF has a positive effect on MSC differentiation in renal tissue. Owing to their highly renoprotective capacity, GDNF-MSCs represent a possible novel cell-based paradigm for treatment of glomerulonephritis.

Encapsulated mesenchymal stromal cells for in vivo transplantation

Immunomodulatory human mesenchymal stromal cells (hMSC) have been incorporated into therapeutic protocols to treat secondary inflammatory responses post-spinal cord injury (SCI) in animal models. However, limitations with direct hMSC implantation approaches may prevent effective translation for therapeutic development of hMSC infusion into post-SCI treatment protocols. To circumvent these limitations, we investigated the efficacy of alginate microencapsulation in developing an implantable vehicle for hMSC delivery. Viability and secretory function were maintained within the encapsulated hMSC population, and hMSC secreted anti-inflammatory cytokines upon induction with the pro-inflammatory factors, TNF-α and IFN-γ. Furthermore, encapsulated hMSC modulated inflammatory macrophage function both in vitro and in vivo, even in the absence of direct hMSC-macrophage cell contact and promoted the alternative M2 macrophage phenotype. In vitro, this was evident by a reduction in macrophage iNOS expression with a concomitant increase in CD206, a marker for M2 macrophages. Finally, Sprague-Dawley rat spinal cords were injured at vertebra T10 via a weight drop model (NYU model) and encapsulated hMSC were administered via lumbar puncture 24 h post-injury. Encapsulated hMSC localized primarily in the cauda equina of the spinal cord. Histological assessment of spinal cord tissue 7 days post-SCI indicated that as few as 5 × 10(4) encapsulated hMSC yielded increased numbers of CD206-expressing macrophages, consistent with our in vitro studies. The combined findings support the inclusion of immobilized hMSC in post-CNS trauma tissue protective therapy, and suggest that conversion of macrophages to the M2 subset is responsible, at least in part, for tissue protection.

Therapeutic efficacy of cord blood-derived mesenchymal stromal cells for the prevention of acute graft-versus-host disease in a xenogenic mouse model

Human mesenchymal stromal cells (MSCs) have been successfully utilized for the treatment of refractory graft-versus-host disease (GvHD). Despite the large number of in vitro and in vivo models developed for clarifying their immunomodulatory properties, the mechanism of action of MSCs remains elusive and their efficacy controversial. Here, we tested the ability of cord blood-derived MSCs to alleviate the symptoms of GvHD induced by the injection of human peripheral blood mononuclear cells into NOD/SCID/γc(-) mice. In this in vivo xeno-GvHD model, we demonstrate that a single MSC injection is able to inhibit GvHD in terms of clinical signs and related mortality. We also show that in this model MSCs act by both immunomodulating T-cells and fostering recovery after irradiation. The translational impact of these findings could provide a reliable preclinical model for studying the efficacy, dosage, and time of administration of human MSCs for the prevention of acute GvHD.

Original article anti-oxidant pathways are stimulated by mesenchymal stromal cells in renal repair after ischemic injury

BACKGROUND AIMS

Ischemia-reperfusion (IR) injury is a common cause of acute renal failure. Bone marrow (BM)-derived mesenchymal stromal cells (MSC) delivered after renal IR are renoprotective, but knowledge of the protective mechanism is still in development. This investigation analyzed the protective molecular mechanisms of MSC, in particular relating to modulated oxidative stress.

METHODS

In vivo and in vitro models of renal IR were analyzed with and without MSC. In vivo, adult male Sprague-Dawley rats were subjected to 40-min unilateral renal IR. Rat BM-derived MSC were administered at 24 h post-IR (IR + MSC). Other groups had IR but no MSC, or MSC but no ischemia (all groups n = 4). Apoptosis, inflammation, oxidative stress and reparative signal transduction molecules or growth factors were studied 4 days post-IR. In vitro, protection by MSC against oxidative stress (0.4 mm hydrogen peroxide) was investigated using rat renal tubular epithelial cells (NRK52E) with or without MSC in co-culture (tissue culture trans-well inserts), followed by similar analyses to the in vivo investigation.

RESULTS

In vivo, kidneys of IR + MSC animals had significantly increased cell proliferation/regeneration (cells positive for proliferating cell nuclear antigen, expression of epidermal growth factor), increased heme-oxygenase-1 (improved cell survival, anti-oxidant) and decreased 8-OHdG (decreased oxidative stress). In vitro, MSC delivered with oxidative stress significantly decreased apoptosis and Bax (pro-apoptotic protein), and increased mitosis and phospho-ERK1/2, thereby minimizing the damaging outcome and maximizing the regenerative effect after oxidative stress.

CONCLUSIONS

The benefits of MSC, in IR, were primarily pro-regenerative, sometimes anti-apoptotic, and novel anti-oxidant mechanisms were identified.

Mesenchymal stem cells: from experiment to clinic

There is currently much interest in adult mesenchymal stem cells (MSCs) and their ability to differentiate into other cell types, and to partake in the anatomy and physiology of remote organs. It is now clear these cells may be purified from several organs in the body besides bone marrow. MSCs take part in wound healing by contributing to myofibroblast and possibly fibroblast populations, and may be involved in epithelial tissue regeneration in certain organs, although this remains more controversial. In this review, we examine the ability of MSCs to modulate liver, kidney, heart and intestinal repair, and we update their opposing qualities of being less immunogenic and therefore tolerated in a transplant situation, yet being able to contribute to xenograft models of human tumour formation in other contexts. However, such observations have not been replicated in the clinic. Recent studies showing the clinical safety of MSC in several pathologies are discussed. The possible opposing powers of MSC need careful understanding and control if their clinical potential is to be realised with long-term safety for patients.

Kidney repair and stem cells: a complex and controversial process

Over the last decade, stem cells have been the topic of much debate and investigation for their regenerative potential in the case of renal injury. This review focuses on bone marrow stem cells (BMSC) for renal repair and the potential origins of the controversial results between studies. Some authors have shown that BMSC can differentiate into renal cells and reverse renal dysfunction while others obtained contradictory results. One significant variation between these studies is the choice of BMSC used. According to the literature and our own experience, unfractionated bone marrow cells and hematopoietic stem cells are able to lead to long-term cell tissue engraftment and repair, whereas mesenchymal stem cells have a short-term paracrine effect. Detection of the bone-marrow-derived cells is also an important source of error. However, the major difference between studies is the model of kidney injury used. Two categories of models have to be distinguished: acute and chronic kidney disease. However, variation within these categories also exists. The outcomes of various strategies for BMSC transplantation after injury to the kidney must be compared within a single model and cannot be transposed from one model to another.

Mesenchymal stem cells as a therapeutic approach to glomerular diseases: benefits and risks

Most studies using adult stem cells (ASCs) and progenitor cells as potential therapeutics for kidney disorders have been conducted in models of acute kidney injury, where the damage mainly affects the tubulointerstitium. The results are promising, whereas the underlying mechanisms are still being discussed controversially. Glomerular diseases have not received as much attention. Likely reasons include the often insidious onset, rendering the choice of optimal treatment timing difficult, and the fact that chronic diseases may require long-term therapy. In this mini review, we summarize current strategies in adult stem cell-based therapies for glomerular diseases. In addition, we focus on possible side effects of stem cell administration that have been reported recently, that is, profibrotic actions and maldifferentiation of mesenchymal stem cells.

Adipose tissue derived mesenchymal stem cell (AD-MSC) promotes skin wound healing in diabetic rats

AIMS

Stem cells are a new hope to ameliorate impaired diabetic wound healing. The purpose of this study was to evaluate the effect of adipose tissue derived mesenchymal stem cells (AD-MSCs) on wound healing in a diabetic rat model.

METHODS

Twenty-six rats became diabetic by a single intraperitoneal injection of streptozotocin. Six rats served as non-diabetic (non-DM). Diabetic rats were divided into two equal groups randomly; control and treatment. Six weeks later, a full-thickness circular excisional wound was created on the dorsum of each rat. AD-MSCs were injected intra-dermally around the wounds of treatment group. PBS was applied to control and non-DM groups. The wound area was measured every other day. After wound healing completion, full thickness skin samples were taken from the wound sites for evaluation of volume density of collagen fibers, length and volume density of vessels, and numerical density of fibroblasts by stereological methods.

RESULTS

AD-MSCs accelerated wound healing rate in diabetic rats, but did not increase length and volume density of the vessels and volume density of the collagen fibers. AD-MSCs decreased the numerical density of fibroblasts.

CONCLUSIONS

We concluded that AD-MSCs enhances diabetic wound healing rate probably by other mechanisms rather than enhancing angiogenesis or accumulating collagen fibers.

Sources of adult mesenchymal stem cells applicable for musculoskeletal applications - a systematic review of the literature

Mesenchymal stem cells (MSCs) were first discovered by Friedenstein and his colleagues in 1976 from bone marrow. The unique property of these cells was their potential to develop into fibroblastic colony forming cells. Since Friedenstein’s discovery of these cells the interest in adult MSCs has been progressively growing. Nowadays MSCs are defined as undeveloped biological cells capable of proliferation, self renewal and regenerating tissues. All these properties of MSCs have been discovered in the past 35 years. MSCs can play a crucial role in tissue engineering, organogenesis, gene therapy, transplants as well as tissue injuries. These cells were mainly extracted from bone marrow but there have been additional sources for MSCs discovered in the laboratories including: muscle, dermis, trabecular bone, adipose tissue, periosteum, pericyte, blood, synovial membrane and so forth. The discovery of the alternative sources of MSCs helps widen the application of these cells in different areas of medicine. By way of illustration, they can be used in various therapeutic purposes such as tissue regeneration and repair in musculoskeletal diseases including osteonecrosis of femoral head, stimulating growth in children with osteogenesis imperfecta, disc regeneration, osteoarthritis and duchenne muscular dystrophy. In order to fully comprehend the characteristics and potential of MSCs future studies in this field are essential.

Adult mesenchymal stem cells and cell surface characterization - a systematic review of the literature

Human adult mesenchymal stem cells (MSCs) were first identified by Friedenstein et al. when observing a group of cells that developed into fibroblastic colony forming cells (CFU-F). Ever since, the therapeutic uses and clinical applications of these cells have increased research and interest in this field. MSCs have the potential to be used in tissue engineering, gene therapy, transplants and tissue injuries. However, identifying these cells can be a challenge. Moreover, there are no articles bringing together and summarizing the cell surface markers of MSCs in adults. The purpose of this study is to summarize all the available information about the cell surface characterization of adult human MSCs by identifying and evaluating all the published literature in this field. We have found that the most commonly reported positive markers are CD105, CD90, CD44, CD73, CD29, CD13, CD34, CD146, CD106, CD54 and CD166. The most frequently reported negative markers are CD34, CD14, CD45, CD11b, CD49d, CD106, CD10 and CD31. A number of other cell surface markers including STRO-1, SH2, SH3, SH4, HLA-A, HLA-B, HLA-C, HLA-DR, HLA-I, DP, EMA, DQ (MHC Class II), CDIO5, Oct 4, Oct 4A, Nanog, Sox-2, TERT, Stat-3, fibroblast surface antigen, smooth muscle alpha-actin, vimentin, integrin subunits alpha4, alpha5, beta1, integrins alphavbeta3 and alphavbeta5 and ICAM-1 have also been reported. Nevertheless, there is great discrepancy and inconsistency concerning the information available on the cell surface profile of adult MSCs and we suggest that further research is needed in this field to overcome the problem.

Mesenchymal stem cell seeding promotes reendothelialization of the endovascular stent

This study is designed to make a novel cell seeding stent and to evaluate reendothelialization and anti-restenosis after the stent implantation. In comparison with cell seeding stents utilized in previous studies, Mesenchymal stem cells (MSCs) have advantages on promoting of issue repair. Thus it was employed to improve the reendothelialization effects of endovascular stent in present work. MSCs were isolated by density gradient centrifugation and determined as CD29(+) CD44(+) CD34(-) cells by immunofluorescence and immunocytochemistry; gluten and polylysine coated stents were prepared by ultrasonic atomization spray, and MSCs seeded stents were made through rotation culture according to the optimized conditions that were determined in previous studies. The results from animal experiments, in which male New Zealand white rabbits were used, show that the reendothelialization of MSCs coated stents can be completed within one month; in comparison with 316L stainless steel stents (316L SS stents) and gluten and polylysine coated stents, the intimal hyperplasia and in-stent restenosis are significantly inhibited by MSCs coated stents. Endovascular stent seeded with MSCs promotes reendothelialization and inhibits the intimal hyperplasia and in-stent restenosis compared with the 316L SS stents and the gluten and polylysine coated stents.

Mesenchymal stem cell transplantation increases expression of vascular endothelial growth factor in papain-induced emphysematous lungs and inhibits apoptosis of lung cells

BACKGROUND

Pulmonary emphysema is characterized by loss of alveolar structures. We have found that bone marrow (BM) mesenchymal stem cell (MSC) transplantation ameliorates papain-induced pulmonary emphysema. However, the underlying mechanism is not completely understood. It has been shown that blocking the vascular endothelial growth factor (VEGF) signaling pathway leads to apoptosis of lung cells and pulmonary emphysema, and MSC are capable of secreting VEGF. We hypothesized that MSC transplantation may have a protective effect on pulmonary emphysema by increasing VEGF-A expression and inhibiting apoptosis of lung cells.

METHODS

We examined the morphology and expression of VEGF-A in rat lung after papain treatment and MSC transplantation. We also used a co-culture system in which MSC and cells prepared from papain-treated lungs or control lungs were cultured together. The levels of VEGF-A in cells and culture medium were determined, and apoptosis of cultured lung cells was evaluated.

RESULTS

VEGF-A expression in rat lungs was decreased after papain treatment, which was partly rescued by MSC transplantation. MSC production of VEGF-A was increased when MSC were co-cultured with cells prepared from papain-treated lungs. Furthermore, the apoptosis of papain-treated lung cells was inhibited when co-cultured with MSC. The induction of MSC production of VEGF-A by papain-treated lung cells was inhibited by adding anti-tumor necrosis factor (TNF)-alpha antibody to the medium.

CONCLUSIONS

The protective effect of MSC transplantation on pulmonary emphysema may be partly mediated by increasing VEGF-A expression and inhibiting the apoptosis of lung cells. TNF-alpha released from papain-treated lung cells induces MSC to secret VEGF-A.

Homing pathways of mesenchymal stromal cells (MSCs) and their role in clinical applications

Mesenchymal stromal cells (MSCs) have come into focus for an increasing number of cellular therapies. Since most clinical protocols use intravenous application of MSCs, it has become important to understand their trafficking in the bloodstream. Moreover, since relatively little is known where the transplanted MSCs might locate, a better understanding of involved homing mechanisms will likely shed light on how MSCs exert their therapeutic effects. This review focuses on the current knowledge of homing pathways of transplanted MSCs. We describe regulatory signalling molecules and receptors involved. An outlook is given on significance of these findings for the future use of MSCs as a cellular therapeutic.

Effects of transplanted mesenchymal stem cells isolated from Wharton's jelly of caprine umbilical cord on cutaneous wound healing; histopathological evaluation

The aim of this study was to investigate the effects of transplanted Wharton's jelly mesenchymal stem cells (WJMSCs) of caprine umbilical cord on cutaneous wound healing process in goat. After collection of caprine pregnant uterus of mixed breed goats from abattoir, the Wharton's jelly (WJ) of umbilical cord was harvested. The tissues were minced in ventilated flasks and explant culture method was used for separating mesenchymal stem cells (MSCs). The isolated cells were immunostained for Actin protein, histochemically assayed for the presence of alkaline phosphatase activity, and analyzed for detection of matrix receptors (CD44) and hematopoetic lineage markers (CD34), using flow cytometery. After The isolated cells, 3×10(6) MSCs were stained with BrdU and prepared for transplantation to each wound. Four 3-cm linear full thickness skin incisions were made on both sides of thoracic vertebrate of four Raeini goats (two wounds on each side). The left wounds were implanted with MSCs in 0.6 ml of Phosphate buffer saline (PBS), and the right wounds considered as control group that received 0.6 ml of PBS. The samples were taken from the wounds 7 and 12 days after the wounding, and healing process was compared histologically between the two groups. Anti-BrdU staining showed that the transplanted cells were still alive in the wound bed during the study. The histopathological study revealed that re-epithelialization was complete at days 7 in treated wounds with WJMSCs, whereas in control wound the wounds still showed incomplete epithelialization 12 days after wounding. Also, microscopic evaluation showed less inflammation, thinner granulation tissue formation with minimum scar in the treated wounds in comparison with control wounds. In conclusion, this study demonstrates the beneficial effect of caprine WJMSCs in cutaneous wound healing in goat.

Kidney preservation by bone marrow cell transplantation in hereditary nephropathy

The prospect of cell-based therapy for kidney disease remains controversial despite its immense promise. We had previously shown that transplanting bone marrow and hematopoietic stem cells could generate renal cells and lead to the preservation of kidney function in a mouse model for cystinosis (Ctns(-/-)) that develops chronic kidney injury, 4 months post transplantation. Here, we determined the long-term effects of bone marrow stem cell transplantation on the kidney disease of Ctns(-/-) mice 7 to 15 months post transplantation. Transfer of bone marrow stem cells expressing a functional Ctns gene provided long-term protection to the kidney. Effective therapy, however, depended on achieving a relatively high level of donor-derived blood cell engraftment of Ctns-expressing cells, which was directly linked to the quantity of these cells within the kidney. In contrast, kidney preservation was dependent neither on renal cystine content nor on the age of the mice at the time of transplant. Most of the bone marrow-derived cells within the kidney were interstitial and not epithelial, suggesting that the mechanism involved an indirect protection of the tubules. Thus, our model may help in developing strategies to enhance the potential success of cell-based therapy for kidney injury and in understanding some of the discrepancies currently existing in the field.

Mesenchymal stromal cells improve renal injury in anti-Thy 1 nephritis by modulating inflammatory cytokines and scatter factors

MSC (mesenchymal stromal cells) can differentiate into renal adult cells, and have anti-inflammatory and immune-modulating activity. In the present study, we investigated whether MSC have protective/reparative effects in anti-Thy1 disease, an Ab (antibody)-induced mesangiolysis resulting in mesangioproliferative nephritis. We studied five groups of rats: (i) rats injected with anti-Thy1.1 Ab on day 0 (group A); (ii) rats injected with anti-Thy1.1 Ab on day 0+MSC on day 3 (group B); (iii) rats injected with anti-Thy1.1 Ab on day 0+mesangial cells on day 3 (group C); (iv) rats injected with saline on day 0+MSC on day 3 (group D); and (v) rats injected with saline on day 0 (group E). Rats were killed on days 1, 3, 7 and 14. MSC prevented the increase in serum creatinine, proteinuria, glomerular monocyte influx and glomerular histopathological injury. Furthermore, MSC suppressed the release of IL-6 (interleukin-6) and TGF-β (transforming growth factor-β), modulated glomerular PDGF-β (platelet-derived growth factor-β), and reset the scatter factors and their receptors, potentiating HGF (hepatocyte growth factor)/Met and inactivating MSP (macrophage-stimulating protein)/Ron (receptor origin nantaise). Few MSC were found in the kidney. These results indicate that MSC improve anti-Thy 1 disease not by replacing injured cells, but by preventing cytokine-driven inflammation and modulating PDGF-β and the scatter factors, i.e. systems that regulate movement and proliferation of monocytes and mesangial cells.