Human Umbilical Cord Blood Cells Research Articles

Review: Pathobiological aspects of the local bone marrow renin-angiotensin system: a review

The local haematopoietic bone marrow (BM) renin-angiotensin system (RAS) mediates pathobiological alterations of haematopoiesis in an autocrine/paracrine/intracrine fashion. Recent data further indicated the existence of angiotensin-converting enzyme (ACE) in human primitive lympho-haematopoietic cells, embryonic, foetal and adult haematopoietic tissues. Human umbilical cord blood cells also express renin, angiotensinogen, and ACE mRNAs. As ACE and other angiotensin peptides function in human haematopoietic stem cells (HSCs) throughout haematopoietic ontogeny and adulthood, local RAS could also have a function in HSC plasticity, and the development of haematological neoplastic disorders. The presence of ACE on leukaemic blast cells within leukaemic BM, on erythroleukaemic cells, ACE-expressing macrophages in lymph nodes of Hodgkin disease, renin activity in leukaemic blasts, angiotensin II as an autocrine growth factor for AML, increased renin gene activity during NUP98-HOXA9 enhanced blast formation, higher levels of BB9/ACE (+) AML isoforms, and altered JAK-STAT pathway as a link between RAS and leukaemia indicated the wide pathobiological aspects of local BM RAS. The comparable biological actions of local RASs throughout the human body (including myocardium, pancreas, pituitary gland, ovary and kidney) represent the true basis for the search of their prominence in tissue functions. Recent data and perspectives of the local BM RAS in health and disease are reviewed in this paper.

The Effect of Human Umbilical Cord Blood Cells on Survival and Cytokine Production by Post-Ischemic Astrocytes in Vitro

Cerebral ischemia induces death of all neural cell types within the region affected by the loss of blood flow. We have shown that administering human umbilical cord blood cells after a middle cerebral artery occlusion in rats significantly reduces infarct size, presumably by rescuing cells within the penumbra. In this study we examined whether the cord blood cells enhanced astrocyte survival in an in vitro model of hypoxia with reduced glucose availability. Primary astrocyte cultures were incubated for 2 h in no oxygen (95% N, 5% CO(2)) and low glucose (1% compared to 4.5%) media. Cord blood mononuclear cells were added to half the cultures at the beginning of hypoxia. Astrocyte viability was determined using fluorescein diacetate/propidium iodide (FDA/PI) labeling and cytokine production by the astrocytes measured using ELISA. In some studies, T cells, B cells or monocytes/macrophages isolated from the cord blood mononuclear fraction with magnetic antibody cell sorting (MACS) were used instead to determine which cellular component of the cord blood mononuclear fraction was responsible for the observed effects. Co-culturing mononuclear cord blood cells with astrocytes during hypoxia stimulated production of IL-6 and IL-10 during hypoxia. The cord blood T cells decreased survival of the astrocytes after hypoxia but had no effect on the examined cytokines. Our data demonstrate that the tested cord blood fractions do not enhance astrocyte survival when delivered individually, suggesting there is either another cellular component that is neuroprotective or an interaction of all the cells is essential for protection.

Comparison of human cord blood engraftment between immunocompromised mouse strains

AbstractThe nonobese diabetic/severe combined immune deficiency (NOD-scid) xenotransplantation model is the “gold standard” for assaying human hematopoietic stem cell activity. Systematic advancements, such as depletion of natural killer cell activity with anti-CD122 antibody, direct intrafemoral injection, and deletion or truncation of IL2Rγ, have improved human cell engraftment; however, questions remain whether these mouse models are equivalent or, if not, which model is superior for assaying hematopoietic stem cell activity. To address this, we compared overall engraftment and multilineage differentiation of near-limiting doses of lineage-depleted human umbilical cord blood cells by direct intrafemoral injection into NOD/Lt-scid, NOD/Shi-scid, NOD/Lt-scid/IL2Rγnull (NSG), and NOD/Shi-scid/IL2Rγnull mice. Transplantation into NSG mice generated moderately higher human engraftment levels in bone marrow compared with other strains. At limiting doses, NSG mice of both sexes were 3.6-fold more sensitive in detecting SCID-repopulating cells compared with NOD/Lt-scid mice. However, NSG females exhibited higher engraftment at limiting cell doses, resulting in an overall increase in SCID-repopulating cell detection of 9-fold. Both NSG and NOD/Shi-scid/IL2Rγnull support significantly improved engraftment in peripheral tissues compared with NOD/Lt-scid and NOD/Shi-scid mice, whereas NSG mice provide greater human engraftment in bone marrow than all other strains, especially at limiting doses.

Effect of simultaneous expression of various usoforms of vascular endothelial growth factor VEGF and fibroblast growth factor FGF2 on proliferation of human umbilical cord blood cells HUVEC

Effect of simultaneous expression of various usoforms of vascular endothelial growth factor VEGF and fibroblast growth factor FGF2 on proliferation of human umbilical cord blood cells HUVEC

Transplantation of Umbilical Cord Blood Stem Cells for Treating Spinal Cord Injury

Spinal cord injury (SCI) develops primary and secondary damage to neural tissue and this often results in permanent disability of the motor and sensory functions. However, there is currently no effective treatment except methylprednisolone, and the use of methylprednisolone has also been questioned due to its moderate efficacy and the drug's downside. Regenerative medicine has remarkably developed since the discovery of stem cells, and many studies have suggested the potential of cell-based therapies for neural injury. Especially, the therapeutic potential of human umbilical cord blood cells (hUCB cells) for intractable neurological disorders has been demonstrated using in vitro and vivo models. The hUCB cells are immune naïve and they are able to differentiate into other phenotypes, including the neural lineage. Their ability to produce several neurotropic factors and to modulate immune and inflammatory reactions has also been noted. Recent evidence has emerged suggesting alternative pathways of graft-mediated neural repair that involve neurotrophic effects. These effects are caused by the release of various growth factors that promote cell survival, angiogenesis and anti-inflammation, and this is all aside from a cell replacement mechanism. In this review, we present the recent findings on the stemness properties and the therapeutic potential of hUCB as a safe, feasible and effective cellular source for transplantation in SCI. These multifaceted protective and restorative effects from hUCB grafts may be interdependent and they act in harmony to promote therapeutic benefits for SCI. Nevertheless, clinical studies with hUCB are still rare because of the concerns about safety and efficiency. Among these concerns, the major histocompatibility in allogeneic transplantation is an important issue to be addressed in future clinical trials for treating SCI.

Gene expression profiles of cryopreserved CD34 + human umbilical cord blood cells are related to their bone marrow reconstitution abilities in mouse xenografts

Human umbilical cord blood (UCB) cells are an alternative source of hematopoietic stem cells for treatment of leukemia and other diseases. It is very difficult to assess the quality of UCB cells in the clinical situation. Here, we sought to assess the quality of UCB cells by transplantation to immunodeficient mice. Cryopreserved CD34 + UCB cells from twelve different human donors were transplanted into sublethally irradiated NOD/shi-scid Jic mice. In parallel, the gene expression profiles of the UCB cells were determined from oligonucleotide microarrays. UCB cells from three donors failed to establish an engraftment in the host mice, while the other nine succeeded to various extents. Gene expression profiling indicated that 71 genes, including HOXB4, C/EBP-β, and ETS2, were specifically overexpressed and 23 genes were suppressed more than 2-fold in the successful UCB cells compared to those that failed. Functional annotation revealed that cell growth and cell cycle regulators were more abundant in the successful UCB cells. Our results suggest that hematopoietic ability may vary among cryopreserved UCB cells and that this ability can be distinguished by profiling expression of certain sets of genes.

Migration of human umbilical cord blood cells into rat liver.

Cell therapy provides an effective strategy for the treatment of an impaired liver. Human umbilical cord blood progenitor cells have the potential to differentiate into hepatocytes. Progenitor cells transplanted into the spleen could migrate directly into the liver through portal circulation. To track migration of human umbilical cord blood progenitor cells in cirrhotic rat liver after intrasplenic transplantation and to prove the possibility similar behavior of human umbilical cord blood nucleated cells in humans. Umbilical cord blood samples from full-term deliveries will be collected after obtaining an informed consent from the mother. The collection procedure will be conducted after completion of delivery and will not interfere with the normal obstetric procedures. Adult male Sprague Dawley rats were subjected to liver cirrhosis by intraperitoneal injection of thioacetamide. Cirrhotic rats were treated with human umbilical cord blood nucleated cells by intra-splenic transplantation. Migration of intrasplenic transplanted human umbilical cord blood cells to the liver was successfully documented with Immunohistochemistry. The liver and spleen from recipient animals were removed. Histopathological and immunohistochemical analysis were performed 20 weeks after intrasplenic injection of the cells. Intrasplenically injected cells migrate to the liver of recipient animals. Human cord blood nucleated cells have the potential to differentiate into hepatocytes and substantially improve the histology and function of the cirrhotic liver in rats. Relocation into liver after intrasplenic transplantation could be detected by immunohistochemistry. Transdifferentiated cells could be efficiently stained with antihuman hepatocytes.

Reversal of Hepatic Fibrosis by Human CD34(+) Stem/Progenitor Cell Transplantation in Rats.

Human umbilical cord blood (UCB) cells have many advantages as grafts for cell transplantation. Here, we transplant UCB cells into injured liver fibrosis, investigated the hepatic potential of UCB cells both in vitro and in vivo. a CCl4 rat model with liver fibrosis was prepared. Human (UCB) CD34(+) stem cell was separated with MACS (magnetic cell sorting). Cells were cultured with and without hepatic differentiation medium. Rats were divided into 3 groups; group (1): control healthy, group (2): CCl4 injected rats and group 3: CCl4/CD34(+)injected rats with human differentiated and undifferentiated cells through intrahepatic (IH) and intravenous (IV) routes. A significant elevation was detected in serum albumin in CCl4/CD34(+) compared to the CCl4 group (p<0.001). Serum ALT, had a significant decrease of its level after administration of stem cells compared to the CCl4 group (p<0.001). However, it was still significantly higher than control (p<0.001) with no significant difference between the groups that received stem cells. Histopathological examination of liver tissue showed that stem cells have a significant antifibrotic effect. Concerning gene expression, the collagen gene (rat) was highly expressed in the CCl4 group whereas its expression was significantly decreased after administration of stem cells. Human albumin and matrix metalloproteinase (MMP2) genes were expressed in liver tissues in the groups that received stem cells. Highest expression was in the group that received un-differentiated cells I.V. human UCB CD34(+) stem cells can ameliorate liver fibrosis in rats.

Regulatory functions of TRAIL in hematopoietic progenitors: human umbilical cord blood and murine bone marrow transplantation

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) signaling pathway has selective toxicity to malignant cells. The TRAIL receptors DR4 and DR5 are expressed at low levels in human umbilical cord blood cells (3-15%) and are upregulated by incubation with the cognate ligand, triggering apoptosis in 70-80% of receptor-positive cells (P<0.001). Apoptosis is not induced in hematopoietic progenitors, as determined from sustained severe combined immunodeficiency reconstituting potential and clonogenic activity. Furthermore, elimination of dead cells after incubation with TRAIL for 72 h results in a threefold enrichment in myeloid progenitors. Exposure to TRAIL in semisolid cultures showed synergistic activity of DR4 and granulocyte/macrophage colony-stimulating factor in recruiting lineage-negative (lin(-)) and CD34(+) progenitors and in promoting the formation of large colonies. In murine bone marrow, approximately 30% of lin(-) cells express TRAIL-R2 (the only murine receptor), and the receptor is upregulated after transplantation in cycling and differentiating donor cells that home to the host marrow. However, this receptor is almost ubiquitously expressed in the most primitive (lin(-)SCA-1(+)c-kit(+)) progenitors, and stimulates the clonogenic activity of lin(-) cells (P<0.001), suggesting a tropic function after transplantation. It is concluded that TRAIL does not trigger apoptosis in hematopoietic progenitors, and upregulation of its cognate receptors under stress conditions mediates tropic signaling that supports recovery from hypoplasia.

Regulation of Chondrogenesis by Transforming Growth Factor-ß3 and Insulin-like Growth Factor-1 from Human Mesenchymal Umbilical Cord Blood Cells

Mature articular cartilage is vulnerable to injuries and disease processes that cause irreversible tissue damage because of its limited capacity for self-repair. Umbilical cord blood is a source of mesenchymal stem cells, which can give rise to cells of different lineages, including cartilage, bone, and fat. Cellular condensation is a required step in the initiation of mesenchymal chondrogenesis. We attempted to differentiate cells from umbilical cord blood into chondrocytes with insulin-like growth factor 1 (IGF-1) and transforming growth factor-ss3 (TGF-ss3). Cells were grown in high density micromass and monolayer culture systems and then evaluated for expression of type II collagen, aggrecan, and Sox9. Umbilical cord blood from 130 patients was harvested. Expression of type II collagen, aggrecan, and Sox9 was detected after 14 days in TGF-ss3- and IGF-1-stimulated cells in both types of culture (monolayer and micromass). On Day 21 in the micromass culture, expression levels were greater than they were at 14 days for all genes. TGF-ss3 was found to be more efficient at promoting chondrogenesis than IGF-1. By western blot, we also found that after 3 weeks, the expression of type II collagen was greater in micromass culture with TGF-ss3. TGF-ss3 used in micromass culture is the best growth factor for promoting the proliferation and differentiation of mesenchymal cells from umbilical cord blood during chondrogenesis. This approach may provide an alternative to autologous grafting.

Human umbilical cord blood endothelial progenitor cells decrease vein graft neointimal hyperplasia in SCID mice

AimsVein graft endothelial damage is a key step in the development of neointimal hyperplasia, leading to vein graft failure. We sought to determine whether exogenous endothelial progenitor cells could promote vein graft re-endothelialization, and thereby ameliorate neointimal hyperplasia. Methods and resultsCarotid artery interposition grafting was performed with syngeneic inferior vena cavae in mice with severe combined immunodeficiency (SCID). Lineage-negative human umbilical cord blood (hUCB) cells (or medium alone) were injected into vein-grafted mice intra-operatively and 2 weeks post-operatively. In vein grafts from hUCB cell-injected mice, we found human HLA-expressing endothelial cells, as well as increased levels of VEGF and FGF-2. Furthermore, hUCB cells secreted VEGF and FGF-2 in vitro. The markedly enhanced endothelial regeneration, likely resulting from both direct engraftment and paracrine actions of hUCB cells, inhibited inflammatory response, diminished intimal cell proliferation, and reduced neointimal hyperplasia in the vein grafts. ConclusionshUCB cells may accelerate vein graft re-endothelialization via both direct differentiation into endothelial cells and release of paracrine factors to enhance endothelial regeneration and reduce inflammation. These data highlight a potential therapeutic role for cellular therapy in vessel injury.

Mannitol facilitates neurotrophic factor up‐regulation and behavioural recovery in neonatal hypoxic‐ischaemic rats with human umbilical cord blood grafts

We recently demonstrated that blood–brain barrier permeabilization using mannitol enhances the therapeutic efficacy of systemically administered human umbilical cord blood (HUCB) by facilitating the entry of neurotrophic factors from the periphery into the adult stroke brain. Here, we examined whether the same blood–brain barrier manipulation approach increases the therapeutic effects of intravenously delivered HUCB in a neonatal hypoxic-ischaemic (HI) injury model. Seven-day-old Sprague–Dawley rats were subjected to unilateral HI injury and then at day 7 after the insult, animals intravenously received vehicle alone, mannitol alone, HUCB cells (15k mononuclear fraction) alone or a combination of mannitol and HUCB cells. Behavioural tests at post-transplantation days 7 and 14 showed that HI animals that received HUCB cells alone or when combined with mannitol were significantly less impaired in motor asymmetry and motor coordination compared with those that received vehicle alone or mannitol alone. Brain tissues from a separate animal cohort from the four treatment conditions were processed for enzyme-linked immunosorbent assay at day 3 post-transplantation, and revealed elevated levels of GDNF, NGF and BDNF in those that received HUCB cells alone or when combined with mannitol compared with those that received vehicle or mannitol alone, with the combined HUCB cells and mannitol exhibiting the most robust neurotropic factor up-regulation. Histological assays revealed only sporadic detection of HUCB cells, suggesting that the trophic factor–mediated mechanism, rather than cell replacement per se, principally contributed to the behavioural improvement. These findings extend the utility of blood–brain barrier permeabilization in facilitating cell therapy for treating neonatal HI injury.

Administration of Human Umbilical Cord Blood Cells Produces Interleukin-10 (IL-10) in IL-10 Deficient Mice Without Immunosuppression

Recent studies from our laboratory have shown that intravenous administration of human umbilical cord blood (HUCB) mononuclear cells to mice improved blood glucose levels, survival, atherosclerosis and prostate cancer. In this study, we examined the effect of HUCB cells on the production of IL-10 levels in IL-10 knockout mice. It has been proposed that administration of IL-10 may be beneficial in the treatment of inflammatory bowl disease. The results show that mice treated with HUCB cells (100 x 10(6)) produce IL-10, as demonstrated by both qualitative and quantitative analyses, and that the levels of this cytokine persisted until the mice were sacrificed (5.5 months after administration). Immunohistochemical staining of the intestine using HuNu antibody cocktail demonstrated the presence of HUCB cells in the knockout mouse. Although the mice did not receive any immunosuppression, there was no evidence of graft-versus-host disease. Our data suggest that HUCB cells are capable of producing IL-10, and the use of these cells or HUCB may be indicated in the treatment of certain human diseases.

Human umbilical cord blood cells in infarcted rats

Therapy with bone marrow-derived cells has been used in ischemic patients with reported success. The aim of this study was to determine the therapeutic efficacy of fresh and frozen human umbilical cord blood cells (hUCB) in Wistar rats submitted to permanent occlusion of the left coronary artery. Three hours after myocardial infarction, 2 x 10(7) hUCB cells or vehicle were administered by intramyocardial injection. The animals were divided into five groups: control (N = 10), sham operated (N = 10), infarcted that received vehicle (N = 9), infarcted treated with cryopreserved hUCB (N = 7), and infarcted treated with fresh hUCB (N = 5). Cardiac function was evaluated by electrocardiogram (ECG) and echocardiogram (ECHO) before cell therapy, and by ECG, ECHO, cardiopulmonary test, and left ventricular pressure measurements 3 weeks later. After 3 weeks, both groups treated with hUCB still had Q wave present in L1, âQRS >90 degrees and reduced shortening fraction (less than 50%). In addition, cardiac indexes of left ventricular contractility and relaxation were 5484 +/- 875 and -4032 +/- 643 mmHg (cryopreserved hUCB) and 4585 +/- 955 and -2862 +/- 590 mmHg (fresh hUCB), respectively. These values were not statistically different from those of saline-treated animals. Cardiopulmonary exercise test profile was typical of infarcted hearts; exercise time was about 14 min and maximal VO2 was 24.77 +/- 5.00 mL.kg-1.min-1. These data show that hUCB therapy did not improve the cardiac function of infarcted animals or prevent cardiac remodeling.

Applications of Human Umbilical Cord Blood Cells in Central Nervous System Regeneration

In recent decades, there has been considerable amount of information about embryonic stem cells (ES). The dilemma facing scientists interested in the development and use of human stem cells in replacement therapies is the source of these cells, i.e. the human embryo. There are many ethical and moral problems related to the use of these cells. Hematopoietic stem cells from umbilical cord blood have been proposed as an alternative source of embryonic stem cells. After exposure to different agents, these cells are able to express antigens of diverse cellular lineages, including the neural type. The In vitro manipulation of human umbilical cord blood (hUCB) cells has shown their stem capacity and plasticity. These cells are easily accessible, In vitro amplifiable, well tolerated by the host, and with more primitive molecular characteristics that give them great flexibility. Overall, these properties open a promising future for the use of hUCB in regenerative therapies for the Central Nervous System (CNS). This review will focus on the available literature concerning umbilical cord blood cells as a therapeutic tool for the treatment of neurodegenerative diseases.

In vitro non-viral lipofectamine delivery of the gene for glial cell line-derived neurotrophic factor to human umbilical cord blood CD34+ cells

Using a lipofection technique, we explored a non-viral delivery of plasmid DNA encoding a rat pGDNF (glial cell line-derived neurotrophic factor) to CD34+ cells derived from human umbilical cord blood (HUCB) cells in order to obtain cells stably expressing the GDNF gene. The target gene GDNF was amplified from cortex cells of newborn Sprague–Dawley rats by reverse transcriptase polymerase chain reaction (RT-PCR) and inserted into vector pEGFP-N1 to construct the eukaryotic expression vector pEGFP/GDNF. The positive clones were identified by sequencing and endonuclease digestion. The expression of pEGFP/GDNF-transfected HUCB cells CD34+ was examined by ELISA. Single fragment of 640 bp was obtained after the rat GDNF cDNA was amplified by RT-PCR. Two fragments of about 4.3 kb and 640 pb were obtained after digestion of recombinant plasmid pEGFP/GDNF with XhoI/KpnI. The nucleic acid fragment of 640 bp was confirmed to agree well with the sequence of GDNF gene published by GenBank. The expression of GDNF mRNA and the level of GDNF from pEGFP/GDNF-transfected CD34+ cells were increased substantially, compared with pEGFP control plasmid transfected CD34+ cells ( P < 0.05). Moreover, co-culture of primary rat cells with the pEGFP/GDNF-transfected CD34+ cells promoted enhanced neuroprotection against oxygen-glucose deprivation induced cell dysfunctions. The present results support the use of the non-viral plasmid liposome for therapeutic gene expression for stem cell therapy.

Human Umbilical Cord Blood Cells Decrease Microglial Survival In Vitro

When human umbilical cord blood (HUCB) cells are systemically administered following middle cerebral artery occlusion (MCAO) in rats, they produce a reduction in infarct size resulting in recovery of motor function. Rats receiving HUCB cells have a less severe inflammatory response compared to MCAO stroke rats. The purpose of this study was to determine the interaction between HUCB cells and the main resident immune cells of the brain (microglia) under normoxic and hypoxic conditions in vitro. Primary microglial cultures were incubated for 2 h in no oxygen (95% N, 5% CO(2)) and low glucose (1%) media. Mononuclear HUCB cells were added to half the cultures at the beginning of the hypoxia conditions. Microglial viability was determined using fluorescein diacetate/propidium iodide (FDA/PI) labeling and cytokine expression using ELISA. In some studies, CD11b+ or CD19+ cells isolated from the HUCB mononuclear fraction with magnetic antibody cell sorting (MACS) were used instead of the mononuclear fraction. Co-culturing mononuclear HUCB cells with microglia decreased viability of the microglia during hypoxia. In the microglial monocultures, hypoxia significantly increased release of IL-1beta compared to normoxia, while adding HUCB cells in the hypoxia condition decreased IL-1beta concentrations to the same level as in the normoxia monocultures. Both CD11b+ and CD19+ HUCB cells decreased microglial viability during normoxia and hypoxia. Our data suggest that HUCB cells may produce a soluble factor that decreases viability of microglia.

Epigenetic changes to human umbilical cord blood cells cultured with three proteins indicate partial reprogramming to a pluripotent state

We have previously reported the existence of a subpopulation of cells from human umbilical cord blood capable of differentiating into oligodendrocytes, Schwann cells, bone, muscle, and endothelial cells despite their origins as CD45-positive cells. These stem cells (called FSFl cells) arise only after a period in vitro in medium containing FGF4, SCF, and Flt-3 ligand (FSFl medium) during which they express the pluripotency genes Oct4 and Nanog. The objective of this study was to determine if the novel expression of these pluripotency genes coupled with the newly acquired ability of these cells to differentiate into all three germ layers was the result of epigenetic changes to these cells after reprogramming in FSFl medium. We confirm that CD45-derived FSFl cells express Oct4 protein at levels similar to that observed among undifferentiated embryonic stem cells, during which time acetylated histones H3 and H4 display increased binding at the promoter region of Oct4. Changes to binding of acetylated histones at Oct4 when these cells are in a differentiated state (either prior to FSFl culture or after in vitro differentiation into neural cells) and when they are undifferentiated suggest that this is one way by which these cells acquire their pluripotency. While DNA hypermethylation at this gene region as well as the continued H3 and H4 acetylation at the CD45 promoter region among FSFl cells indicate this is only a partial reprogramming event, this is a significant step toward non-transgene reprogramming of somatic cells.

Human Umbilical Cord Blood Mononuclear Cell Transplantation in Rats with Intrinsic Sphincter Deficiency

To evaluate the effectiveness of the human umbilical cord blood (HUCB) transplantation for the treatment of intrinsic sphincter deficiency (ISD), we analyzed the short term effects of HUCB mononuclear cell transplantation in rats with induced-ISD. ISD was induced in rats by electro-cauterization of periurethral soft tissue with HUCB mononuclear cell injection after 1 week. The sphincter function measured by mean leak point pressure was significantly improved in the experimental group compared to the control group at 4 weeks. (91.75±18.99 mmHg vs. 65.02±22.09 mmHg, P=0.001). Histologically, the sphincter muscle was restored without damage while in the control group it appeared markedly disrupted with atrophic muscle layers and collagen deposit. We identified injected HUCB cells in the tissue sections by Di-I signal and Prussian blue staining. HUCB mononuclear cell injection significantly improved urethral sphincter function, suggesting its potential efficacy in the treatment of ISD.

Human umbilical cord blood cell therapy blocks the morphological change and recruitment of CD11b‐expressing, isolectin‐binding proinflammatory cells after middle cerebral artery occlusion

Secondary neurodegeneration resulting from stroke is mediated by delayed proinflammatory signaling and immune cell activation. Although it remains unknown which cell surface markers signify a proinflammatory phenotype, increased isolectin binding occurs on CD11b-expressing immune cells within injured brain tissue. Several reports have confirmed the efficacy of human umbilical cord blood (HUCB) cell therapy in reducing ischemic injury in rat after middle cerebral artery occlusion (MCAO), and these effects were attributed in part to dampened neuroinflammation. The present study examined the time course of lectin binding to cells of microglia/macrophage lineage within 96 hr after MCAO and whether delayed HUCB cell treatment alters the migration and/or morphological characteristics of these cells throughout the period of infarct expansion. Isolectin binding was up-regulated in response to injury, was maximal at 96 hr, and colocalized with cells that expressed the putative proinflammatory markers MMP-9 and nitric oxide. Isolectin-tagged fluorescence was also significantly increased at 72 hr and localized to greater numbers of amoeboid, CD11b-expressing cells relative to 51 hr. Treatment with 1 x 10(6) HUCB cells significantly reduced total lectin binding at 72 hr, as well as the total area occupied by lectin-tagged fluorescence at both 51 and 72 hr, relative to vehicle-treated controls. This effect was accompanied by a shift in the morphology of CD11b-positive cells from amoeboid to ramified shape. These data indicate that HUCB cell therapy suppressed the recruitment of proinflammatory, isolectin-binding cells during the period of infarct expansion, thus offering a potential mechanism for the protective effects of HUCB cell therapy.