The combination of granulocyte colony-stimulating factor and stem cell factor significantly increases the number of bone marrow-derived endothelial cells in brains of mice following cerebral ischemia

Hematopoietic Growth Factors Regulate the Entry of Monocytes into the Adult Brain via Chemokine Receptor CCR5

Monocytes are circulating macrophage precursors generated from bone marrow hematopoietic stem cells. In adults, monocytes continuously replenish cerebral border-associated macrophages under physiological conditions. Monocytes also rapidly infiltrate the brain in pathological settings. The mechanisms of recruiting monocyte-derived macrophages into the brain under pathological conditions have been extensively studied. However, it remains unclear how monocytes enter the brain to renew border-associated macrophages under physiological conditions. Using both in vitro and in vivo approaches, this study reveals that a combination of two hematopoietic growth factors, stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF), complementarily and synergistically enhances the adhesion of monocytes to cerebral endothelial cells in a dose-dependent manner. Cysteine-cysteine chemokine receptor 5 (CCR5) in brain endothelial cells, but not the cell adhesion molecules mediating neuroinflammation-related infiltration of monocyte-derived macrophages, modulates SCF+G-CSF-enhanced monocyte-endothelial cell adhesion. Blocking CCR5 or genetically deleting CCR5 reduces monocyte-endothelial cell adhesion induced by SCF+G-CSF. The SCF+G-CSF-enhanced recruitment of bone marrow-derived monocytes/macrophages into the cerebral perivascular space is also reduced in adult CCR5 knockout mice. This study demonstrates the role of SCF and G-CSF in regulating the entry of monocytes into the adult brain to replenish perivascular macrophages.

Hematopoietic growth factors Regulate Entry of Monocytes into the Adult Brain via Chemokine Receptor CCR5

Monocytes are circulating macrophage precursors and are generated from bone marrow hematopoietic stem cells. In the adults, monocytes continuously replenish cerebral border-associated macrophages under a physiological condition. Monocytes also rapidly infiltrate into the brain in the settings of pathological conditions. The mechanisms of recruiting monocyte-derived macrophages into the brain under pathological conditions have been extensively studied. However, it remains unclear how monocytes enter the brain for renewal of border-associated macrophages under the physiological condition. Using both in vitro and in vivo approaches, this study reveals that the combination of two hematopoietic growth factors, stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF), complementarily and synergistically enhances adhesion of monocytes to cerebral endothelial cells in a dose dependent manner. Cysteine-cysteine chemokine receptor 5 (CCR5) in brain endothelial cells, but not cell adhesion molecules mediating neuroinflammation-related infiltration of monocyte-derived macrophages, modulates the SCF+G-CSF-enhanced monocyte-endothelial cell adhesion. Blocking CCR5 or genetically deleting CCR5 reduces monocyte-endothelial cell adhesion induced by SCF+G-CSF. SCF+G-CSF-enhanced recruitment of bone marrow-derived monocytes/macrophages in cerebral perivascular space is also reduced in adult CCR5 knockout mice. This study demonstrates the contribution of SCF and G-CSF in regulating the entry of monocytes into the adult brain to replenish perivascular macrophages.

Cell-based treatment of cerebral palsy: still a long way ahead

BACKGROUND

Cerebral palsy (CP) is a permanent neurodevelopmental disorder with considerable global disability. Various rehabilitation strategies are currently available. However, none represents a convincing curative result. Cellular therapy recently holds much promise as an alternative strategy to repair neurologic defects.

METHOD

In this narrative review, a comprehensive search of the MEDLINE and ClinicalTrials.gov was made, using the terms: "cell therapy" and "cerebral palsy", including published and registered clinical studies, respectively.

RESULTS

The early effects of these studies demonstrated that using cell therapy in CP patients is safe and improves the deficits for a variable duration. Despite such hopeful early bird results, the long-term outcomes are not conclusive.

CONCLUSIONS

Due to the heterogeneous nature of CP, personal factors seem essential to consider. Cell dosage, routes of administration, and repeated dosing are pivotal to establish optimal personalized treatments. Future clinical trials should consider employing other cell types, specific cell modifications before administration, and cell-free platforms.

Effects of Low-Intensity Pulsed Ultrasound on Myelosuppression of Rats Induced by Chemotherapy Drugs With Cell Cycle Specificity

OBJECTIVES

To explore the ameliorating effects of low-intensity pulsed ultrasound (LIPUS) on Sprague Dawley rat myelosuppression induced by cell cycle specificity drugs (docetaxel, mitotic phase sensitive; and etoposide, gap 2 phase sensitive).

METHODS

Rats were respectively administered docetaxel (100 mg/kg) or etoposide (110 mg/kg) by intraperitoneal injection for 4 consecutive days. Then the rats were divided randomly into a LIPUS group and a non-LIPUS group. In the LIPUS group, the right femoral metaphysis of rats was treated by LIPUS (acoustic intensity, 200 mW/cm² ; frequency, 0.3 MHz; and duty cycle, 20%) for 20 minutes on 7 consecutive days from day 5. The rats of the non-LIPUS group were treated without ultrasound output. A blood cell count, an enzyme-linked immunosorbent assay, a real-time quantitative polymerase chain reaction, and hematoxylin-eosin staining were applied to detect the results.

RESULTS

Low-intensity pulsed ultrasound significantly promoted the counts of bone marrow nucleated cells, white blood cells, immunoglobulin A (IgA), IgG, granulocyte colony-stimulating factor, stem cell factor, and intercellular cell adhesion molecule 1 and reduced the counts of vascular cell adhesion molecule 1 whether in the docetaxel or etoposide group (P < .05). Low-intensity pulsed ultrasound only increased the expression level of IgM in the docetaxel group but decreased the level of interleukin 6 in the etoposide group (P < .05).

CONCLUSIONS

Low-intensity pulsed ultrasound has potential to be a noninvasive treatment for myelosuppression caused by different cell cycle-sensitive chemotherapy drugs.

Colony-Stimulating Factors on Mobilizing CD34+ Cells and Improving Neurological Functions in Patients With Stroke: A Meta-Analysis and a Systematic Review

Background and Purpose: CSF therapy is considered a promising therapeutic approach for stroke. We performed a meta-analysis to explore the safety and efficacy of CSF in published clinical stroke studies. Methods: We searched articles online and manually. Two reviewers selected studies independently, selecting data based on study quality, characteristics of intervention (administration time, observation time, type, dose, and injection approach of CSF), and the baseline characteristics of patients (age, sex, hypertension, diabetes, smoker, and lipids) were extracted. Main prognosis outcomes were measured as all-cause death in severe adverse events (SAE) and recurrent stroke in SAE. Secondary outcomes were measured as CD34+ cell counts in periphery blood at day 5, National Institutes of Health Stroke Scale (NIHSS), and Barthel index (BI), Side effects of CSF were taken as the indicator of safety. STATA13 software was used to perform the meta-analysis.Keywords: Stroke, Colony-stimulating factor, Meta-analysis, therapy, Neurological Diseases Results: This meta-analysis involved 485 patients from eight studies. Among them, 475 patients from seven studies were gauged SAE (all-cause death), 393 patients from six studies were checked SAE (recurrent stroke); 137 patients from three studies underwent CD34⁺ measurement, 389 patients from six studies were tested NIHSS and 307 patients from five studies accessed BI. Compared with the control group, both all-causes death (RR= 1.73, 95%CI= (0.61, 4.92), P=0.735, I²=0.0%) and recurrent stroke (RR= 0.43, 95%CI= (0.14, 1.32), P=0.214, I²=33.1%) present no statistical differences, indicating that the application of CSF does not statistically alter the prognosis of patients with stroke. The application of CSF effectively enhanced CD34+ cell counts in periphery blood at day 5 (SMD= 1.23, 95%CI= (0.54, 1.92), P=0.04, I²=69.0%) but did not statistically impact NIHSS (SMD= -0.40, 95%CI= (-0.93, 0.13), P ≤ 0.001, I²=79.7%) or BI (SMD= 0.04, 95%CI= (-0.38, 0.46), P=0.068, I²=54.3%). Conclusion: Our study consolidates the security of CSF administration for its exerting no effect on detrimental outcomes. It has proven to be effective in elevating CD34+ cell counts in periphery blood at day 5, indicating CSF may participate in stroke recovery, but its efficacy in stroke recovery remains detected.

CADASIL from Bench to Bedside: Disease Models and Novel Therapeutic Approaches

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a monogenic disease caused by NOTCH3 mutations and characterized by typical clinical, neuroradiological, and pathological features. NOTCH3 belongs to a family of highly conserved transmembrane receptors rich of epidermal growth factor repeats, mostly expressed in vascular smooth muscle cells and pericytes, which perform essential developmental functions and are involved in tissues maintenance and renewal. To date, no therapeutic option for CADASIL is available except for few symptomatic treatments. Novel in vitro and in vivo models are continuously explored with the aim to investigate underlying pathogenic mechanisms and to test novel therapeutic approaches. In this scenario, knock-out, knock-in, and transgenic mice studies have generated a large amount of information on molecular and biological aspects of CADASIL, despite that they incompletely reproduce the human phenotype. Moreover, the field of in vitro models has been revolutionized in the last two decades by the introduction of induced pluripotent stem cells (iPSCs) technology. As a consequence, novel therapeutic approaches, including immunotherapy, growth factors administration, and antisense oligonucleotides, are currently under investigation. While waiting that further studies confirm the promising results obtained, the data reviewed suggest that our therapeutic approach to the disease could be transformed, generating new hope for the future.

Amelioration of cyclophosphamide-induced myelosuppression during treatment to rats with breast cancer through low-intensity pulsed ultrasound

To investigate the alleviating effects of low-intensity pulsed ultrasound (LIPUS) on myelosuppression of Sprague–Dawley rats with breast cancer induced by cyclophosphamide (CTX). Breast cancer in rats was triggered by intragastric gavage with 7,12-dimethylbenz[a]anthracene (150 mg/kg). Then, the rats with breast cancer were randomly allocated to the LIPUS group (n=50) and the control group (n=50). The LIPUS group was injected intraperitoneally with CTX (50 mg/kg) for 4 consecutive days and underwent LIPUS treatment at femoral metaphysis 20 min per day from the first day of injection for 7 consecutive days. The control group was injected with CTX (50 mg/kg) and treated with LIPUS without energy output. Blood, enzyme-linked immunosorbent assay (ELISA), real-time quantitative polymerase chain reaction, Hematoxylin and Eosin (H&E) staining, and scanning electron microscopy were applied to detect the changes. The results indicated that LIPUS significantly promoted the proliferation of bone marrow nucleated cells, white blood cells (WBCs), IgA, IgG, and IgM in the peripheral blood (P<0.05) without the damage to liver and kidney function simultaneously. The mechanisms may result from the LIPUS alleviation effect on bone marrow hematopoietic function through regulating cytokines such as LIPUS can increase the expression of granulocyte colony-stimulating factor (G-CSF), stem cell factor, transforming growth factor-β, and intercellular cell adhesion molecule-1, meanwhile LIPUS will decrease the expression of interleukin-6, tumor necrosis factor-α, and vascular cell adhesion molecule-1. LIPUS has potential to be a new adjuvant therapy method in clinic for ameliorating chemotherapy-induced myelosuppression.

The contribution of stem cell factor and granulocyte colony-stimulating factor in reducing neurodegeneration and promoting neurostructure network reorganization after traumatic brain injury

Traumatic brain injury (TBI) is a major cause of death and disability in young adults worldwide. TBI-induced long-term cognitive deficits represent a growing clinical problem. Stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF) are involved in neuroprotection and neuronal plasticity. However, the knowledge concerning reparative efficacy of SCF + G-CSF treatment in post-acute TBI recovery remains incomplete. This study aims to determine the efficacy of SCF + G-CSF on post-acute TBI recovery in young adult mice. The controlled cortical impact model of TBI was used for inducing a severe damage in the motor cortex of the right hemisphere in 8-week-old male C57BL mice. SCF + G-CSF treatment was initiated 3 weeks after induction of TBI. Severe TBI led to persistent motor functional deficits (Rota-Rod test) and impaired spatial learning function (water maze test). SCF + G-CSF treatment significantly improved the severe TBI-impaired spatial learning function 6 weeks after treatment. TBI also caused significant increases of Fluoro-Jade C positive degenerating neurons in bilateral frontal cortex, striatum and hippocampus, and significant reductions in MAP2⁺ apical dendrites and overgrowth of SMI312⁺ axons in peri-TBI cavity frontal cortex and in the ipsilateral hippocampal CA1 at 24 weeks post-TBI. SCF + G-CSF treatment significantly reduced TBI-induced neurodegeneration in the contralateral frontal cortex and hippocampal CA1, increased MAP2⁺ apical dendrites in the peri-TBI cavity frontal cortex, and prevented TBI-induced axonal overgrowth in both the peri-TBI cavity frontal cortex and ipsilateral hippocampal CA1.These findings reveal a novel pathology of axonal overgrowth after severe TBI and demonstrate a therapeutic potential of SCF + G-CSF in ameliorating severe TBI-induced long-term neuronal pathology, neurostructural network malformation, and impairments in spatial learning.

Extension of Tissue Plasminogen Activator Treatment Window by Granulocyte-Colony Stimulating Factor in a Thromboembolic Rat Model of Stroke

When given beyond 4.5 h of stroke onset, tissue plasminogen activator (tPA) induces deleterious side effects in the ischemic brain, notably, hemorrhagic transformation (HT). We examined the efficacy of granulocyte-colony stimulating factor (G-CSF) in reducing delayed tPA-induced HT, cerebral infarction, and neurological deficits in a thromboembolic (TE) stroke model, and whether the effects of G-CSF were sustained for longer periods of recovery. After stroke induction, rats were given intravenous saline (control), tPA (10 mg/kg), or G-CSF (300 μg/kg) + tPA 6 h after stroke. We found that G-CSF reduced delayed tPA-associated HT by 47%, decreased infarct volumes by 33%, and improved motor and neurological deficits by 15% and 25%, respectively. It also prevented delayed tPA treatment-induced mortality by 46%. Immunohistochemistry showed 1.5- and 1.8-fold enrichment of the endothelial progenitor cell (EPC) markers CD34+ and VEGFR2 in the ischemic cortex and striatum, respectively, and 1.7- and 2.8-fold increases in the expression of the vasculogenesis marker von Willebrand factor (vWF) in the ischemic cortex and striatum, respectively, in G-CSF-treated rats compared with tPA-treated animals. Flow cytometry revealed increased mobilization of CD34+ cells in the peripheral blood of rats given G-CSF. These results corroborate the efficacy of G-CSF in enhancing the therapeutic time window of tPA for stroke treatment via EPC mobilization and enhancement of vasculogenesis.

Granulocyte-colony stimulating factor and umbilical cord blood cell transplantation: Synergistic therapies for the treatment of traumatic brain injury

Traumatic brain injury (TBI) is now characterized as a progressive, degenerative disease and continues to stand as a prevalent cause of death and disability. The pathophysiology of TBI is complex, with a variety of secondary cell death pathways occurring which may persist chronically following the initial cerebral insult. Current therapeutic options for TBI are minimal, with surgical intervention or rehabilitation therapy existing as the only viable treatments. Considering the success of stem-cell therapies in various other neurological diseases, their use has been proposed as a potential potent therapy for patients suffering TBI. Moreover, stem cells are highly amenable to adjunctive use with other therapies, providing an opportunity to overcome the inherent limitations of using a single therapeutic agent. Our research has verified this additive potential by demonstrating the efficacy of co-delivering human umbilical cord blood (hUCB) cells with granulocyte-colony stimulating factor (G-CSF) in a murine model of TBI, providing encouraging results which support the potential of this approach to treat patients suffering from TBI. These findings justify ongoing research toward uncovering the mechanisms which underlie the functional improvements exhibited by hUCB + G-CSF combination therapy, thereby facilitating its safe and effect transition into the clinic. This paper is a review article. Referred literature in this paper has been listed in the reference section. The datasets supporting the conclusions of this article are available online by searching various databases, including PubMed. Some original points in this article come from the laboratory practice in our research center and the authors’ experiences.

Cytokine therapy-mediated neuroprotection in a Friedreich's ataxia mouse model

OBJECTIVES

Friedreich's ataxia is a devastating neurological disease currently lacking any proven treatment. We studied the neuroprotective effects of the cytokines, granulocyte-colony stimulating factor (G-CSF) and stem cell factor (SCF) in a humanized murine model of Friedreich's ataxia.

METHODS

Mice received monthly subcutaneous infusions of cytokines while also being assessed at monthly time points using an extensive range of behavioral motor performance tests. After 6 months of treatment, neurophysiological evaluation of both sensory and motor nerve conduction was performed. Subsequently, mice were sacrificed for messenger RNA, protein, and histological analysis of the dorsal root ganglia, spinal cord, and cerebellum.

RESULTS

Cytokine administration resulted in significant reversal of biochemical, neuropathological, neurophysiological, and behavioural deficits associated with Friedreich's ataxia. Both G-CSF and SCF had pronounced effects on frataxin levels (the primary molecular defect in the pathogenesis of the disease) and a regulators of frataxin expression. Sustained improvements in motor coordination and locomotor activity were observed, even after onset of neurological symptoms. Treatment also restored the duration of sensory nerve compound potentials. Improvements in peripheral nerve conduction positively correlated with cytokine-induced increases in frataxin expression, providing a link between increases in frataxin and neurophysiological function. Abrogation of disease-related pathology was also evident, with reductions in inflammation/gliosis and increased neural stem cell numbers in areas of tissue injury.

INTERPRETATION

These experiments show that cytokines already clinically used in other conditions offer the prospect of a novel, rapidly translatable, disease-modifying, and neuroprotective treatment for Friedreich's ataxia. Ann Neurol 2017;81:212-226.

Translating G-CSF as an Adjunct Therapy to Stem Cell Transplantation for Stroke

Among recently investigated stroke therapies, stem cell treatment holds great promise by virtue of their putative ability to replace lost cells, promote endogenous neurogenesis,and produce behavioral and functional improvement through their "bystander effects." Translating stem cell in the clinic, however, presents a number of technical difficulties. A strategy suggested to enhance therapeutic utility of stem cells is combination therapy, i.e., co-transplantation of stem cells or adjunct treatment with pharmacological agents and substrates,which is assumed to produce more profound therapeutic benefits by circumventing limitations of individual treatments and facilitating complementary brain repair processes. We previously demonstrated enhanced functional effects of cotreatment with granulocyte-colony stimulating factor (GCSF)and human umbilical cord blood cell (hUCB) transplantation in animal models of traumatic brain injury (TBI). Here,we suggest that the aforementioned combination therapy may also produce synergistic effects in stroke. Accordingly, G-CSF treatment may reduce expression of pro-inflammatory cytokines and enhance neurogenesis rendering a receptive microenvironment for hUCB engraftment. Adjunct treatment of GCSF with hUCB may facilitate stemness maintenance and guide neural lineage commitment of hUCB cells. Moreover, regenerative mechanisms afforded by G-CSF-mobilized endogenous stem cells, secretion of growth factors by hUCB grafts and G-CSF-recruited endothelial progenitor cells(EPCs), as well as the potential graft–host integration that may promote synaptic circuitry re-establishment could altogether produce more pronounced functional improvement in stroked rats subjected to a combination G-CSF treatment and hUCB transplantation. Nevertheless, differences in pathology and repair processes underlying TBI and stroke deserve consideration when testing the effects of combinatorial G-CSF and hUCB cell transplantation for stroke treatment. Further studies are also required to determine the safety and efficacy of this intervention in both preclinical and clinical stroke studies.

Treatment of Cerebral Palsy with Stem Cells: A Report of 17 Cases

Cerebral Palsy (CP) is a disabling condition that affects a child's life and his/her family irreversibly. It is usually a non-progressive condition but improvement over time is rarely seen. The condition can be due to prenatal hypoxia, metabolic, genetic, infectious, traumatic or other causes. It is therefore a heterogeneous group that results in functional motor disability associated with different degrees of cognitive abnormalities. There are no treatments that can cure or even improve CP and the best available approach aims at functional, social and nutritional supportive care and counseling. In this paper, we report 17 sequential patients with CP treated with intrathecal administration of Bone Marrow Mononuclear Cells (BMMC). All patients had an uneventful post-injection course with 73% of the evaluable patients treated having a good response using the Gross Motor Function Classification System (GMFCS). The average improvement was 1.3 levels on the GMFCS with cognitive improvements as well.

Growth factor therapy sequesters inflammation in affording neuroprotection in cerebrovascular diseases

INTRODUCTION

In recent years, accumulating evidence has demonstrated the key role of inflammation in the progression of cerebrovascular diseases. Inflammation can persist over prolonged period of time after the initial insult providing a wider therapeutic window. Despite the acute endogenous upregulation of many growth factors after the injury, it is not sufficient to protect against inflammation and to regenerate the brain. Therapeutic approaches targeting both dampening inflammation and enhancing growth factors are likely to provide beneficial outcomes in cerebrovascular disease.

AREAS COVERED

In this mini review, we discuss major growth factors and their beneficial properties to combat the inflammation in cerebrovascular diseases. Emerging biotechnologies which facilitate the therapeutic effects of growth factors are also presented in an effort to provide insights into the future combination therapies incorporating both central and peripheral abrogation of inflammation. Expert commentary: Many studies discussed in this review have demonstrated the therapeutic effects of growth factors in treating cerebrovascular diseases. It is unlikely that one growth factor can be used to treat these complex diseases. Combination of growth factors and anti-inflammatory modulators may clinically improve outcomes for patients. In particular, transplantation of stem cells may be able to achieve both goals of modulating inflammation and upregulating growth factors. Large preclinical studies and multiple laboratory collaborations are needed to advance these findings from bench to bedside.

Combining Growth Factor and Bone Marrow Cell Therapy Induces Bleeding and Alters Immune Response After Stroke in Mice

BACKGROUND AND PURPOSE

Bone marrow cell (BMC)-based therapies, either the transplantation of exogenous cells or stimulation of endogenous cells by growth factors like the granulocyte colony-stimulating factor (G-CSF), are considered a promising means of treating stroke. In contrast to large preclinical evidence, however, a recent clinical stroke trial on G-CSF was neutral. We, therefore, aimed to investigate possible synergistic effects of co-administration of G-CSF and BMCs after experimental stroke in mice to enhance the efficacy compared with single treatments.

METHODS

We used an animal model for experimental stroke as paradigm to study possible synergistic effects of co-administration of G-CSF and BMCs on the functional outcome and the pathophysiological mechanism.

RESULTS

G-CSF treatment alone led to an improved functional outcome, a reduced infarct volume, increased blood vessel stabilization, and decreased overall inflammation. Surprisingly, the combination of G-CSF and BMCs abrogated G-CSFs' beneficial effects and resulted in increased hemorrhagic infarct transformation, altered blood-brain barrier, excessive astrogliosis, and altered immune cell polarization. These increased rates of infarct bleeding were mainly mediated by elevated matrix metalloproteinase-9-mediated blood-brain barrier breakdown in G-CSF- and BMCs-treated animals combined with an increased number of dilated and thus likely more fragile vessels in the subacute phase after cerebral ischemia.

CONCLUSIONS

Our results provide new insights into both BMC-based therapies and immune cell biology and help to understand potential adverse and unexpected side effects.

Induction of Neurorestoration From Endogenous Stem Cells

Neural stem cells (NSCs) persist in the subventricular zone lining the ventricles of the adult brain. The resident stem/progenitor cells can be stimulated in vivo by neurotrophic factors, hematopoietic growth factors, magnetic stimulation, and/or physical exercise. In both animals and humans, the differentiation and survival of neurons arising from the subventricular zone may also be regulated by the trophic factors. Since stem/progenitor cells present in the adult brain and the production of new neurons occurs at specific sites, there is a possibility for the treatment of incurable neurological diseases. It might be feasible to induce neurogenesis, which would be particularly efficacious in the treatment of striatal neurodegenerative conditions such as Huntington's disease, as well as cerebrovascular diseases such as ischemic stroke and cerebral palsy, conditions that are widely seen in the clinics. Understanding of the molecular control of endogenous NSC activation and progenitor cell mobilization will likely provide many new opportunities as therapeutic strategies. In this review, we focus on endogenous stem/progenitor cell activation that occurs in response to exogenous factors including neurotrophic factors, hematopoietic growth factors, magnetic stimulation, and an enriched environment. Taken together, these findings suggest the possibility that functional brain repair through induced neurorestoration from endogenous stem cells may soon be a clinical reality.

PACAP38/PAC1 signaling induces bone marrow-derived cells homing to ischemic brain

Understanding stem cell homing, which is governed by environmental signals from the surrounding niche, is important for developing effective stem cell-based repair strategies. The molecular mechanism by which the brain under ischemic stress recruits bone marrow-derived cells (BMDCs) to the vascular niche remains poorly characterized. Here we report that hypoxia-inducible factor-1α (HIF-1α) activation upregulates pituitary adenylate cyclase-activating peptide 38 (PACAP38), which in turn activates PACAP type 1 receptor (PAC1) under hypoxia in vitro and cerebral ischemia in vivo. BMDCs homing to endothelial cells in the ischemic brain are mediated by HIF-1α activation of the PACAP38-PAC1 signaling cascade followed by upregulation of cellular prion protein and α6-integrin to enhance the ability of BMDCs to bind laminin in the vascular niche. Exogenous PACAP38 confers a similar effect in facilitating BMDCs homing into the ischemic brain, resulting in reduction of ischemic brain injury. These findings suggest a novel HIF-1α-activated PACAP38-PAC1 signaling process in initiating BMDCs homing into the ischemic brain for reducing brain injury and enhancing functional recovery after ischemic stroke. Stem Cells2015;33:1153–1172

Effect of bone marrow stem cell mobilisation on the expression levels of cellular growth factors in a rat model of acute tubular necrosis

The aim of the present study was to observe the mobilisation effects of stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF) on bone marrow stem cells (BMSCs) in rats with renal ischaemia-reperfusion injury. In addition, the effects of the BMSCs on the expression levels of hepatocyte growth factor (HGF) and epidermal growth factor (EGF) were investigated, with the aim to further the understanding of the protective mechanisms of SCF and G-CSF in renal ischaemia-reperfusion injury. The model and treatment groups were established using a model of unilateral renal ischaemia-reperfusion injury, in which the treatment group and the treatment control group were subcutaneously injected once a day with 200 µg/kg SCF and 50 µg/kg G-CSF, 24 h after the modelling, for five consecutive days. The CD34⁺ cell count was measured in the peripheral blood using flow cytometry. The mRNA expression levels of HGF and EGF were determined using polymerase chain reaction analysis, while the protein expression levels of HGF and EGF were detected using immunohistochemistry. The CD34⁺ cell count in the peripheral blood of the treatment and treatment control groups was significantly higher compared with that in the model group (P<0.05). However, CD34 expression levels in the cells from the renal tissues of the model and treatment groups were significantly higher compared with that of the control and treatment control groups (P<0.05), with the greatest increase observed in the treatment group. The mRNA and protein expression levels of HGF and EGF in the treatment group were significantly higher compared with the model group (P<0.05). Therefore, the results indicated that a combination of SCF and G-CSF can promote the repair of acute tubular necrosis. This combination, which can mobilise sufficient numbers of BMSCs to migrate back to the injured site, is a key factor in promoting the repair of renal tubular injury. Upregulation of HGF and EGF was also shown to promote the repair of renal tubular injury.

Endothelial progenitor cells in ischemic stroke: an exploration from hypothesis to therapy

As the population ages and lifestyles change in concordance, the number of patients suffering from ischemic stroke and its associated disabilities is increasing. Studies on determining the relationship between endothelial progenitor cells (EPCs) and ischemic stroke have become a new hot spot and have reported that EPCs may protect the brain against ischemic injury, promote neurovascular repair, and improve long-term neurobehavioral outcomes. More importantly, they introduce a new perspective for prognosis assessment and therapy of ischemic stroke. However, EPCs’ origin, function, influence factors, injury repair mechanisms, and cell-based therapy strategies remain controversial. Particularly, research conducted to date has less clinical studies than pre-clinical experiments on animals. In this review, we summarized and analyzed the current understanding of basic characteristics, influence factors, functions, therapeutic strategies, and disadvantages of EPCs as well as the regulation of inflammatory factors involved in the function and survival of EPCs after ischemic stroke. Identifying potential therapeutic effects of EPCs in ischemic stroke will be a challenging but an incredibly important breakthrough in neurology, which may bring promise for patients with ischemic stroke.

G-CSF as an adjunctive therapy with umbilical cord blood cell transplantation for traumatic brain injury

Traumatic brain injury (TBI), a major contributor to deaths and permanent disability worldwide, has been recently described as a progressive cell death process rather than an acute event. TBI pathophysiology is complicated and can be distinguished by the initial primary injury and the subsequent secondary injury that ensues days after the trauma. Therapeutic opportunities for TBI remain very limited with patients subjected to surgery or rehabilitation therapy. The efficacy of stem cell-based interventions, as well as neuroprotective agents in other neurological disorders of which pathologies overlap with TBI, indicates their potential as alternative TBI treatments. Furthermore, their therapeutic limitations may be augmented when combination therapy is pursued instead of using a single agent. Indeed, we demonstrated remarkable combined efficacy of human umbilical cord blood (hUCB) cell therapy and granulocyte-colony-stimulating factor (G-CSF) treatment in TBI models, providing essential evidence for the translation of this approach to treat TBI. Further studies are warranted to determine the mechanisms underlying therapeutic benefits exerted by hUCB + G-CSF in order to enhance its safety and efficacy in the clinic.

Granulocyte colony-stimulating factor attenuates delayed tPA-induced hemorrhagic transformation in ischemic stroke rats by enhancing angiogenesis and vasculogenesis

Treatment with tissue plasminogen activator (tPA) beyond the therapeutic time window (>4.5 hours post stroke) may produce hemorrhagic transformation (HT). Strategies that could extend the narrow time window of tPA will benefit a significant number of stroke patients. Male Sprague-Dawley rats underwent middle cerebral artery occlusion (MCAo) and given vehicle, tPA (10 mg/kg), or tPA and granulocyte colony-stimulating factor (G-CSF, 300 μg/kg), at 6 hours after MCAo. Twenty-four hours post treatment, G-CSF+tPA-treated stroke rats displayed 25% improvement in neurological functions and 38.9% reduction of hemorrhage, with Western blots showing 1.9- and 1.2-fold increments in Ang-2 expression in the ischemic cortex and striatum, respectively, and 3-fold increase in phosphorylated endothelial nitric oxide synthase expression in the ipsilateral cortex relative to tPA-treated rats. Immunohistochemistry also showed 2- and 2.8-fold increase in von-Willebrand expression, 3.2- and 2.2-fold increased CD34+ expression, and 4- and 13-fold upregulation of VEGFR-2 expression in the ischemic cortex and striatum, respectively, in G-CSF+tPA-treated stroke rats relative to tPA-treated subjects. Altogether, these findings indicate that G-CSF attenuated delayed tPA-induced HT likely via the enhancement of angiogenesis and vasculogenesis. The use of G-CSF to protect the vasculature may improve the clinical outcome of tPA even outside the currently indicated therapeutic window for ischemic stroke.

Cytokine expression patterns and mesenchymal stem cell karyotypes from the bone marrow microenvironment of patients with myelodysplastic syndromes

The purpose of this study was to explore cytokine expression patterns and cytogenetic abnormalities of mesenchymal stem cells (MSCs) from the bone marrow microenvironment of Chinese patients with myelodysplastic syndromes (MDS). Bone marrow samples were obtained from 30 cases of MDS (MDS group) and 30 healthy donors (control group). The expression pattern of cytokines was detected by customized protein array. The karyotypes of MSCs were analyzed using fluorescence in situ hybridization. Compared with the control group, leukemia inhibitory factor, stem cell factor (SCF), stromal cell-derived factor (SDF-1), bone morphogenetic protein 4, hematopoietic stem cell (HSC) stimulating factor, and transforming growth factor-β in the MDS group were significantly downregulated (P<0.05), while interferon-γ (IFN-γ), tumor necrosis factor-α (TNF-α), and programmed death ligand (B7-H1) were significantly upregulated (P<0.05). For chromosome abnormality analysis, the detection rate of abnormal karyotypes (+8, -8, -20, 20q-, -Y, -7, 5q-) was 30% in the MDS group and 0% in the control group. In conclusion, the up- and downregulated expression of these cytokines might play a key role in the pathogenesis of MDS. Among them, SCF and SDF-1 may play roles in the apoptosis of HSCs in MDS; and IFN-γ, TNF-α, and B7-H1 may be associated with apoptosis of bone marrow cells in MDS. In addition, the abnormal karyotypes might be actively involved in the pathogenesis of MDS. Further studies are required to determine the role of abnormal karyotypes in the occurrence and development of MDS.

The role of stem cell factor and granulocyte-colony stimulating factor in treatment of stroke

Stroke is a serious cerebrovascular disease that causes high mortality and persistent disability in adults worldwide. Stroke is also an enormous public health problem and a heavy public financial burden in the United States. Treatment for stroke is very limited. Thrombolytic therapy by tissue plasminogen activator (tPA) is the only approved treatment for acute stroke, and no effective treatment is available for chronic stroke. Developing new therapeutic strategies, therefore, is a critical need for stroke treatment. This article summarizes the discovery of new routes of treatment for acute and chronic stroke using two hematopoietic growth factors, stem cell factor (SCF) and granulocyte-colony stimulating factor (G-CSF). In a study of acute stroke, SCF and G-CSF alone or in combination displays neuroprotective effects in an animal model of stroke. SCF appears to be the optimal treatment for acute stroke as the functional outcome is superior to G-CSF alone or in combination (SCF+G-CSF); however, SCF+G-CSF does show better functional recovery than G-CSF. In a chronic stroke study, the therapeutic effects of SCF and G-CSF alone or in combination appear differently as compared with their effects on the acute stroke. SCF+G-CSF induces stable and long-lasting functional improvement; SCF alone also improves functional outcome but its effectiveness is less than SCF+G-CSF, whereas G-CSF shows no therapeutic effects. Although the mechanism by which SCF+G-CSF repairs the brain in chronic stroke remains poorly understood, our recent findings suggest that the SCF+G-CSF-induced functional improvement in chronic stroke is associated with a contribution to increasing angiogenesis and neurogenesis through bone marrow-derived cells and the direct effects on stimulating neurons to form new neuronal networks. These findings would assist in developing new treatment for stroke. The article presents some promising patents on role of stem cell factor and granulocyte-colony stimulating factor in treatment of stroke.

Stem cells and G-CSF for treating neuroinflammation in traumatic brain injury: aging as a comorbidity factor

Traumatic brain injury (TBI), often called the signature wound of Iraq and Afghanistan wars, is characterized by a progressive histopathology and long-lasting behavioral deficits. Treatment options for TBI are limited and patients are usually relegated to rehabilitation therapy and a handful of experimental treatments. Stem cell-based therapies offer alternative treatment regimens for TBI, and have been intended to target the delayed therapeutic window post-TBI, in order to promote "neuroregeneration," in lieu of "neuroprotection" which can be accomplished during acute TBI phase. However, these interventions may require adjunctive pharmacological treatments especially when aging is considered as a comorbidity factor for post-TBI health outcomes. Here, we put forward the concept that a combination therapy of human umbilical cord blood cell (hUCB) and granulocyte-colony stimulating factor (G-CSF) attenuates neuroinflammation in TBI, in view of the safety and efficacy profiles of hUCB and G-CSF, their respective mechanisms of action, and efficacy of hUCB+G-CSF combination therapy in TBI animal models. Further investigations on the neuroinflammatory pathway as a key pathological hallmark in acute and chronic TBI and also as a major therapeutic target of hUCB+G-CSF are warranted in order to optimize the translation of this combination therapy in the clinic.

Combination therapy of human umbilical cord blood cells and granulocyte colony stimulating factor reduces histopathological and motor impairments in an experimental model of chronic traumatic brain injury

Traumatic brain injury (TBI) is associated with neuro-inflammation, debilitating sensory-motor deficits, and learning and memory impairments. Cell-based therapies are currently being investigated in treating neurotrauma due to their ability to secrete neurotrophic factors and anti-inflammatory cytokines that can regulate the hostile milieu associated with chronic neuroinflammation found in TBI. In tandem, the stimulation and mobilization of endogenous stem/progenitor cells from the bone marrow through granulocyte colony stimulating factor (G-CSF) poses as an attractive therapeutic intervention for chronic TBI. Here, we tested the potential of a combined therapy of human umbilical cord blood cells (hUCB) and G-CSF at the acute stage of TBI to counteract the progressive secondary effects of chronic TBI using the controlled cortical impact model. Four different groups of adult Sprague Dawley rats were treated with saline alone, G-CSF+saline, hUCB+saline or hUCB+G-CSF, 7-days post CCI moderate TBI. Eight weeks after TBI, brains were harvested to analyze hippocampal cell loss, neuroinflammatory response, and neurogenesis by using immunohistochemical techniques. Results revealed that the rats exposed to TBI treated with saline exhibited widespread neuroinflammation, impaired endogenous neurogenesis in DG and SVZ, and severe hippocampal cell loss. hUCB monotherapy suppressed neuroinflammation, nearly normalized the neurogenesis, and reduced hippocampal cell loss compared to saline alone. G-CSF monotherapy produced partial and short-lived benefits characterized by low levels of neuroinflammation in striatum, DG, SVZ, and corpus callosum and fornix, a modest neurogenesis, and a moderate reduction of hippocampal cells loss. On the other hand, combined therapy of hUCB+G-CSF displayed synergistic effects that robustly dampened neuroinflammation, while enhancing endogenous neurogenesis and reducing hippocampal cell loss. Vigorous and long-lasting recovery of motor function accompanied the combined therapy, which was either moderately or short-lived in the monotherapy conditions. These results suggest that combined treatment rather than monotherapy appears optimal for abrogating histophalogical and motor impairments in chronic TBI.

Mobilization of endogenous bone marrow derived endothelial progenitor cells and therapeutic potential of parathyroid hormone after ischemic stroke in mice

Stroke is a major neurovascular disorder threatening human life and health. Very limited clinical treatments are currently available for stroke patients. Stem cell transplantation has shown promising potential as a regenerative treatment after ischemic stroke. The present investigation explores a new concept of mobilizing endogenous stem cells/progenitor cells from the bone marrow using a parathyroid hormone (PTH) therapy after ischemic stroke in adult mice. PTH 1-34 (80 µg/kg, i.p.) was administered 1 hour after focal ischemia and then daily for 6 consecutive days. After 6 days of PTH treatment, there was a significant increase in bone marrow derived CD-34/Fetal liver kinase-1 (Flk-1) positive endothelial progenitor cells (EPCs) in the peripheral blood. PTH treatment significantly increased the expression of trophic/regenerative factors including VEGF, SDF-1, BDNF and Tie-1 in the brain peri-infarct region. Angiogenesis, assessed by co-labeled Glut-1 and BrdU vessels, was significantly increased in PTH-treated ischemic brain compared to vehicle controls. PTH treatment also promoted neuroblast migration from the subventricular zone (SVZ) and increased the number of newly formed neurons in the peri-infarct cortex. PTH-treated mice showed significantly better sensorimotor functional recovery compared to stroke controls. Our data suggests that PTH therapy improves endogenous repair mechanisms after ischemic stroke with functional benefits. Mobilizing endogenous bone marrow-derived stem cells/progenitor cells using PTH and other mobilizers appears an effective and feasible regenerative treatment after ischemic stroke.

Astrocytes require insulin-like growth factor I to protect neurons against oxidative injury

Oxidative stress is a proposed mechanism in brain aging, making the study of its regulatory processes an important aspect of current neurobiological research. In this regard, the role of the aging regulator insulin-like growth factor I (IGF-I) in brain responses to oxidative stress remains elusive as both beneficial and detrimental actions have been ascribed to this growth factor. Because astrocytes protect neurons against oxidative injury, we explored whether IGF-I participates in astrocyte neuroprotection and found that blockade of the IGF-I receptor in astrocytes abrogated their rescuing effect on neurons. We found that IGF-I directly protects astrocytes against oxidative stress (H 2O 2). Indeed, in astrocytes but not in neurons, IGF-I decreases the pro-oxidant protein thioredoxin-interacting protein 1 and normalizes the levels of reactive oxygen species. Furthermore, IGF-I cooperates with trophic signals produced by astrocytes in response to H 2O 2 such as stem cell factor (SCF) to protect neurons against oxidative insult. After stroke, a condition associated with brain aging where oxidative injury affects peri-infarcted regions, a simultaneous increase in SCF and IGF-I expression was found in the cortex, suggesting that a similar cooperative response takes place in vivo. Cell-specific modulation by IGF-I of brain responses to oxidative stress may contribute in clarifying the role of IGF-I in brain aging.

Time-dependent effect of combination therapy with erythropoietin and granulocyte colony-stimulating factor in a mouse model of hypoxic-ischemic brain injury

Erythropoietin (EPO) and granulocyte colony-stimulating factor (G-CSF) are likely to play broad roles in the brain. We investigated the effects of combination therapy with EPO and G-CSF in hypoxic-ischemic brain injury during the acute, subacute, and chronic phases. A total of 79 C57BL/6 mice with hypoxic-ischemic brain injury were randomly assigned acute (days 1-5), subacute (days 11-15) and chronic (days 28-32) groups. All of them were treated with G-CSF (250 μg/kg) and EPO (5000 U/kg) or saline daily for 5 consecutive days. Behavioral assessments and immunohistochemistry for angiogenesis, neurogenesis, and astrogliosis were performed with an 8-week follow-up. Hypoxia-inducible factor-1 (HIF-1) was also measured by Western blot analysis. The results showed that the combination therapy with EPO and G-CSF in the acute phase significantly improved rotarod performance and forelimb-use symmetry compared to the other groups, while subacute EPO and G-CSF therapy exhibited a modest improvement compared with the chronic saline controls. The acute treatment significantly increased the density of CD31(+) (PECAM-1) and α-smooth muscle actin(+) vessels in the frontal cortex and striatum, increased BrdU(+)/PSA-NCAM(+) neurogenesis in the subventricular zone, and decreased astroglial density in the striatum. Furthermore, acute treatment significantly increased the HIF-1 expression in the cytosol and nucleus, whereas chronic treatment did not change the HIF-1 expression, consistent with the behavioral outcomes. These results indicate that the induction of HIF-1 expression by combination therapy with EPO and G-CSF synergistically enhances not only behavioral function but also neurogenesis and angiogenesis while decreasing the astroglial response in a time-dependent manner.

Treatment for salivary gland hypofunction at both initial and advanced stages of Sjögren-like disease: a comparative study of bone marrow therapy versus spleen cell therapy with a 1-year monitoring period

BACKGROUND AIMS

Non-obese diabetic mice (NOD) exhibit autoimmune Sjögren-like disease (SS-like). We reported previously that a combined-therapy consisting of immuno- and cell-based therapy rescued NOD from SS-like. However, therapies tested to date on NOD mice were aimed at the initial phase of SS-like. It is unknown whether therapies are effective in restoring salivary function when given at an advanced phase of SS-like.

METHODS

The efficacy of two therapies (bone marrow versus spleen cells) was compared head-to-head for halting/reversing salivary hypofunction at two critical time points of SS-like (7-week-old NOD with normal saliva output and 20-week-old NOD with minimal saliva). NOD mice were divided into four groups: (i) control, (ii) complete Freund's adjuvant (CFA), (iii) bone marrow transplants with CFA or (iv) spleen cell transplants with CFA. Mice were monitored 8-12 months after therapy.

RESULTS

Both cell therapies were effective during the initial phase of SS-like; salivary flow rates were maintained between 80-100% of pre-symptomatic levels. Spleen cell therapy was better than bone marrow when administered in the initial phase of SS-like. When cell therapies were given at an advanced phase of SS-like (20 weeks and older), salivary flow rates improved but were at best 50% of pre-symptomatic levels. Both cell therapies decreased tumor necrosis factor-α, transforming growth factor-β1 levels and T and B cells while increasing epidermal growth factor and regulatory T cells. Elevated serum epidermal growth factor levels were measured in spleen-treated mice.

CONCLUSIONS

A therapeutic effect in advanced phase disease, albeit in mice, holds promise for humans in which Sjögren syndrome is generally not diagnosed until a late stage.

Novel pathological features and potential therapeutic approaches for CADASIL: insights obtained from a mouse model of CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common condition of hereditary stroke and vascular dementia. CADASIL is caused by Notch3 mutation, leading to progressive degeneration of vascular smooth muscle cells (vSMCs) of the small arteries in the brain. However, the pathogenesis of CADASIL remains largely unknown, and treatment that can stop or delay the progression of CADASIL is not yet available. Using both wild type mice and transgenic mice carrying the human mutant Notch3 gene (CADASIL mice), we have recently characterized the pathological features of CADASIL and determined the therapeutic efficacy of two hematopoietic growth factors, stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF) in CADASIL. Our findings have revealed novel pathological changes in the endothelium of cerebral capillaries and in the neural stem cells (NSCs). We have also observed the impairment of cognitive function in CADASIL mice. Moreover, SCF+G-CSF treatment improves cognitive function, inhibits Notch3 mutation-induced vSMC degeneration, cerebral blood bed reduction, cerebral capillary damage, and NSC loss, and increases neurogenesis and angiogenesis. Here we compile an overview of our recently published studies, which provide new insights into understanding the pathogenesis of CADASIL and developing therapeutic strategies for this devastating neurological disease.

Role of stress-inducible protein-1 in recruitment of bone marrow derived cells into the ischemic brains

Stress-inducible protein-1 (STI-1) is the proposed ligand for the cellular prion protein (PrP^C), which is thought to facilitate recovery following stroke. Whether STI-1 expression is affected by stroke and how its signalling facilitates recovery remain elusive. Brain slices from patients that died of ischemic stroke were collected for STI-1 immunohistochemistry. These findings were compared to results from cell cultures, mice with or without the PrP^C knockout, and rats. Based on these findings, molecular and pharmacological interventions were administered to investigate the underlying mechanisms and to test the possibility for therapy in experimental stroke models. STI-1 was upregulated in the ischemic brains from humans and rodents. The increase in STI-1 expression in vivo was not cell-type specific, as it was found in neurons, glia and endothelial cells. Likewise, this increase in STI-1 expression can be mimicked by sublethal hypoxia in primary cortical cultures (PCCs) in vitro, and appear to have resulted from the direct binding of the hypoxia inducible factor-1α (HIF-1α) to the STI-1 promoter. Importantly, this STI-1 signalling promoted bone marrow derived cells (BMDCs) proliferation and migration in vitro and recruitment to the ischemic brain in vivo, and augmenting its signalling facilitated neurological recovery in part by recruiting BMDCs to the ischemic brain. Our results thus identified a novel mechanism by which ischemic insults can trigger a self-protective mechanism to facilitate recovery.

This work identifies HIF-1α-mediated transcription of STI-1 and PrPc interaction as leading to BMDCs recruitment into ischemic brains following stroke in both patients and animal models of stroke, highlighting novel neuroprotective possibilities.

Granulocyte colony-stimulating factor with or without stem cell factor extends time to premature ovarian insufficiency in female mice treated with alkylating chemotherapy

OBJECTIVE

To examine gonadal protective properties of granulocyte colony-stimulating factor (G-CSF) alone or in combination with stem cell factor (SCF) in female mice treated with high-dose alkylating chemotherapy.

DESIGN

Experimental laboratory animal study.

SETTING

Tertiary care academic hospital and research institute.

ANIMAL(S)

Six- and 8-week-old C57Bl/6 female mice.

INTERVENTION(S)

Adult female mice were treated with [1] cyclophosphamide and busulfan (CTx), [2] CTx + G-CSF/SCF, [3] CTx + G-CSF, or [4] normal saline and dimethyl sulfoxide (DMSO; vehicle control).

MAIN OUTCOME MEASURE(S)

Follicle counts, microvessel density, cellular response to DNA damage, and litter production.

RESULT(S)

G-CSF ± SCF increased microvessel density and decreased follicle loss in CTx-treated female mice compared with CTx-only treated female mice. Mice administered CTx alone exhibited premature ovarian insufficiency, with only 28% of mice producing two litters. However, 100% of mice receiving CTx with G-CSF + SCF, and 80% of mice receiving CTx + G-CSF alone produced at least three litters and 20% of mice in each group produced five litters.

CONCLUSION(S)

Treatment of mice with G-CSF decreases chemotherapy-induced ovarian follicle loss and extends time to premature ovarian insufficiency in female mice. Further studies are needed to validate these preclinical results in humans and compare efficacy with the established GnRH analogue treatments.

The effect of exercise on mobilization of hematopoietic progenitor cells involved in the repair of sciatic nerve crush injury

Object Mobilization of hematopoietic progenitor cells (HPCs) from bone marrow involved in the process of peripheral nerve regeneration occurs mostly through deposits of CD34(+) cells. Treadmill exercise, with either differing intensity or duration, has been shown to increase axon regeneration and sprouting, but the effect of mobilization of HPCs on peripheral nerve regeneration due to treadmill exercise has not yet been elucidated. Methods Peripheral nerve injury was induced in Sprague-Dawley rats by crushing the left sciatic nerve using a vessel clamp. The animals were categorized into 2 groups: those with and without treadmill exercise (20 m/min for 60 minutes per day for 7 days). Cytospin and flow cytometry were used to determine bone marrow progenitor cell density and distribution. Neurobehavioral analysis, electrophysiological study, and regeneration marker expression were investigated at 1 and 3 weeks after exercise. The accumulation of HPCs, immune cells, and angiogenesis factors in injured nerves was determined. A separate chimeric mice study was conducted to assess CD34(+) cell distribution according to treadmill exercise group. Results Treadmill exercise significantly promoted nerve regeneration. Increased Schwann cell proliferation, increased neurofilament expression, and decreased Schwann cell apoptosis were observed 7 days after treadmill exercise. Elevated expression of S100 and Luxol fast blue, as well as decreased numbers of vacuoles, were identified in the crushed nerve 3 weeks after treadmill exercise. Significantly increased numbers of mononuclear cells, particularly CD34(+) cells, were induced in bone marrow after treadmill exercise. The deposition of CD34(+) cells was abolished by bone marrow irradiation. In addition, deposits of CD34(+) cells in crushed nerves paralleled the elevated expressions of von Willebrand factor, isolectin B4, and vascular endothelial growth factor. Conclusions Bone marrow HPCs, especially CD34(+) cells, were able to be mobilized by low-intensity treadmill exercise, and this effect paralleled the significant expression of angiogenesis factors. Treadmill exercise stimulation of HPC mobilization during peripheral nerve regeneration could be used as a therapy in human beings.

Granulocyte-colony stimulating factor in combination with stem cell factor confers greater neuroprotection after hypoxic-ischemic brain damage in the neonatal rats than a solitary treatment

Neonatal hypoxia-ischemia (HI) is a devastating condition resulting in neuronal cell death and often culminates in neurological deficits. Granulocyte-colony stimulating factor (G-CSF) has been shown to have neuroprotective activity via inhibition of apoptosis and inflammation in various stroke models. Stem cell factor (SCF) regulates hematopoietic stem cells in the bone marrow and has been reported to have neuroprotective properties in an experimental ischemic stroke model. In this study we aim to determine the protective effects of G-CSF in combination with SCF treatment after experimental HI. Seven-day old Sprague-Dawley rats were subjected to unilateral carotid artery ligation followed by 2.5 hours of hypoxia. Animals were randomly assigned to five groups: Sham (n=8), Vehicle (n=8), HI with G-CSF treatment (n=9), HI with SCF treatment (n=9) and HI with G-CSF+SCF treatment (coadministration group; n=10). G-CSF (50 µg/kg), SCF (50 µg/kg) and G-CSF+SCF (50 µg/kg) were administered intraperitoneally 1 hour post HI followed by daily injection for 4 consecutive days (five total injections). Animals were euthanized 14 days after HI for neurological testing. Additionally assessment of brain, heart, liver, spleen and kidney atrophy was performed. Both G-CSF and G-CSF+SCF treatments improved body growth and decreased brain atrophy at 14 days post HI. No significant differences were found in the peripheral organ weights between groups. Finally, the G-CSF+SCF coadministration group showed significant improvement in neurological function. Our data suggest that administration of G-CSF in combination with SCF not only prevented brain atrophy but also significantly improved neurological function.

Double gene therapy with granulocyte colony-stimulating factor and vascular endothelial growth factor acts synergistically to improve nerve regeneration and functional outcome after sciatic nerve injury in mice

Peripheral-nerve injuries are a common clinical problem and often result in long-term functional deficits. Reconstruction of peripheral-nerve defects is currently undertaken with nerve autografts. However, there is a limited availability of nerves that can be sacrificed and the functional recovery is never 100% satisfactory. We have previously shown that gene therapy with vascular endothelial growth factor (VEGF) significantly improved nerve regeneration, neuronal survival, and muscle activity. Our hypothesis is that granulocyte colony-stimulating factor (G-CSF) synergizes with VEGF to improve the functional outcome after sciatic nerve transection. The left sciatic nerves and the adjacent muscle groups of adult mice were exposed, and 50 or 100 μg (in 50 μl PBS) of VEGF and/or G-CSF genes was injected locally, just below the sciatic nerve, and transferred by electroporation. The sciatic nerves were transected and placed in an empty polycaprolactone (PCL) nerve guide, leaving a 3-mm gap to challenge nerve regeneration. After 6 weeks, the mice were perfused and the sciatic nerve, the dorsal root ganglion (DRG), the spinal cord and the gastrocnemius muscle were processed for light and transmission electron microscopy. Treated animals showed significant improvement in functional and histological analyses compared with the control group. However, the best results were obtained with the G-CSF+VEGF-treated animals: quantitative analysis of regenerated nerves showed a significant increase in the number of myelinated fibers and blood vessels, and the number of neurons in the DRG and motoneurons in the spinal cord was significantly higher. Motor function also showed that functional recovery occurred earlier in animals receiving G-CSF+VEGF-treatment. The gastrocnemius muscle showed an increase in weight and in the levels of creatine phosphokinase, suggesting an improvement of reinnervation and muscle activity. These results suggest that these two factors acted synergistically and optimized the nerve repair potential, improving regeneration after a transection lesion.

Granulocyte colony-stimulating factor enhances the angiogenetic effect of indirect bypass surgery for chronic cerebral hypoperfusion in a rat model

BACKGROUND

Granulocyte colony-stimulating factor (G-CSF) mobilizes hematopoietic bone marrow cells into systemic circulation and has been used clinically to treat chemotherapy-induced neutropenia. Recently, G-CSF was shown to have neuroprotective and angiogenetic effects in acute cerebral infarction.

OBJECTIVE

To evaluate the effects of G-CSF for angiogenesis after indirect bypass surgery.

METHODS

: Chronic cerebral hypoperfusions were induced in male Wistar rats by permanent bilateral internal carotid artery occlusion (BICAO). After BICAO, unilateral indirect bypass and encephalogaleosynangiosis (EGS) were performed, and human recombinant G-CSF (10 μg/kg) or saline was injected intramuscularly for 5 consecutive days. We measured regional cerebral blood flow (rCBF) by laser Doppler flowmetry and performed immunohistochemical analysis 21 days after BICAO.

RESULTS

BICAO decreased rCBF to 62.52% ± 5.8% of control (P < .01). The rCBF increased significantly 21 days after BICAO in all treatment groups (n = 10; P < .05) except the G-E- group. The rCBF increase observed in the G+E+ group was significantly higher than that observed in other groups. Both G-CSF and EGS treatments significantly increased the number of small vessels (P < .01), and G-CSF and EGS showed additive effect in increasing the number of small vessels.

CONCLUSION

Combined use of G-CSF and indirect bypass surgery induces an increase in rCBF and angiogenesis under conditions of cerebral chronic hypoperfusion. This is the first report to demonstrate that G-CSF can enhance angiogenesis induced by indirect bypass surgery, and that this combined therapy is a safe and easy method of treatment.

Granulocyte colony stimulating factor prevents kidney infarction and attenuates renovascular hypertension

BACKGROUND

G-CSF is a critical regulator of hematopoietic cell proliferation, differentiation and survival. It has been reported that G-CSF attenuates renal injury during acute ischemia-reperfusion. In this study we evaluated the effects of G-CSF on the renal and cardiovascular systems of 2K1C hypertensive mice.

METHODS

Male C57BL/6 mice were subjected to left renal artery clipping (2K1C) or sham operation and were then administered G-CSF (100 μg/kg/day) or vehicle for 14 days.

RESULTS

Arterial pressure was higher in 2K1C + vehicle animals than in 2K1C + G-CSF (150±5 vs. 129±2 mmHg, p<0.01, n=8). Plasma angiotensin I, II and 1-7 concentrations were significantly increased in 2K1C + Vehicle when compared to the normotensive Sham group. G-CSF prevented the increase of these vasoactive peptides. The clipped kidney/contralateral kidney weight ratio showed a less atrophy of the ischemic kidney in the treated group (0.50±0.02 vs. 0.66±0.01, p<0.05). The infarction area in the clipped kidney was completely prevented in 7 out of 8 2K1C + G-CSF mice. Administration of G-CSF protected the clipped kidney from apoptosis.

CONCLUSION

Our data indicate that G-CSF prevents kidney infarction and markedly attenuates the increases in plasma angiotensin levels and hypertension in 2K1C mice, reinforcing the protective effect of G-CSF on kidney ischemia.

Stem cell- and growth factor-based regenerative therapies for avascular necrosis of the femoral head

Avascular necrosis (AVN) of the femoral head is a debilitating disease of multifactorial genesis, predominately affects young patients, and often leads to the development of secondary osteoarthritis. The evolving field of regenerative medicine offers promising treatment strategies using cells, biomaterial scaffolds, and bioactive factors, which might improve clinical outcome. Early stages of AVN with preserved structural integrity of the subchondral plate are accessible to retrograde surgical procedures, such as core decompression to reduce the intraosseous pressure and to induce bone remodeling. The additive application of concentrated bone marrow aspirates, ex vivo expanded mesenchymal stem cells, and osteogenic or angiogenic growth factors (or both) holds great potential to improve bone regeneration. In contrast, advanced stages of AVN with collapsed subchondral bone require an osteochondral reconstruction to preserve the physiological joint function. Analogously to strategies for osteochondral reconstruction in the knee, anterograde surgical techniques, such as osteochondral transplantation (mosaicplasty), matrix-based autologous chondrocyte implantation, or the use of acellular scaffolds alone, might preserve joint function and reduce the need for hip replacement. This review summarizes recent experimental accomplishments and initial clinical findings in the field of regenerative medicine which apply cells, growth factors, and matrices to address the clinical problem of AVN.

Recruitment by SDF-1α of CD34-positive cells involved in sciatic nerve regeneration

Object

Increased integration of CD34+ cells in injured nerve significantly promotes nerve regeneration, but this effect can be counteracted by limited migration and short survival of CD34+ cells. SDF-1α and its receptor mediate the recruitment of CD34+ cells involved in the repair mechanism of several neurological diseases. In this study, the authors investigate the potentiation of CD34+ cell recruitment triggered by SDF-1α and the involvement of CD34+ cells in peripheral nerve regeneration.

Methods

Peripheral nerve injury was induced in 147 Sprague-Dawley rats by crushing the left sciatic nerve with a vessel clamp. The animals were allocated to 3 groups: Group 1, crush injury (controls); Group 2, crush injury and local application of SDF-1α recombinant proteins; and Group 3, crush injury and local application of SDF-1α antibody. Electrophysiological studies and assessment of regeneration markers were conducted at 4 weeks after injury; neurobehavioral studies were conducted at 1, 2, 3, and 4 weeks after injury. The expression of SDF-1α, accumulation of CD34+ cells, immune cells, and angiogenesis factors in injured nerves were evaluated at 1, 3, 7, 10, 14, 21, and 28 days after injury.

Results

Application of SDF-1α increased the migration of CD34+ cells in vitro, and this effect was dose dependent. Crush injury induced the expression of SDF-1α, with a peak of 10–14 days postinjury, and this increased expression of SDF-1α paralleled the deposition of CD34+ cells, expression of VEGF, and expression of neurofilament. These effects were further enhanced by the administration of SDF-1α recombinant protein and abolished by administration of SDF-1α antibody. Furthermore, these effects were consistent with improvement in measures of neurological function such as sciatic function index, electrophysiological parameters, muscle weight, and myelination of regenerative nerve.

Conclusions

Expression of SDF-1α facilitates recruitment of CD34+ cells in peripheral nerve injury. The increased deposition of CD34+ cells paralleled significant expression of angiogenesis factors and was consistent with improvement of neurological function. Utilization of SDF-1α for enhancing the recruitment of CD34+ cells involved in peripheral nerve regeneration may be considered as an alternative treatment strategy in peripheral nerve disorders.

Neuroprotective and Angiogenic Effects of Bone Marrow Transplantation Combined With Granulocyte Colony-Stimulating Factor in a Mouse Model of Amyotrophic Lateral Sclerosis

Bone marrow (BM) cells from amyotrophic lateral sclerosis (ALS) patients show significantly reduced expression of several neurotrophic factors. Monotherapy with either wild-type (WT) BM transplantation (BMT) or granulocyte colony-stimulating factor (GCSF) has only a small clinical therapeutic effect in an ALS mouse model, due to the phenomenon of neuroprotection. In this study, we investigated the clinical benefits of combination therapy using BMT with WT BM cells, plus GCSF after disease onset in ALS mice [transgenic mice expressing human Cu/Zn superoxide dismutase (SOD1) bearing a G93A mutation]. Combined treatment with BMT and GCSF delayed disease progression and prolonged the survival of G93A mice, whereas BMT or GCSF treatment alone did not. Histological study of the ventral horns of lumbar cords from G93A mice treated with BMT and GCSF showed a reduction in motor neuron loss coupled with induced neuronal precursor cell proliferation, increased expression of neurotrophic factors (glial cell line-derived neurotrophic factor, brain-derived neurotrophic factor, vascular endothelial growth factor and angiogenin), and neovascularization compared with controls (vehicle only). Compared with G93A microglial cells, most BM-derived WT cells differentiated into microglial cells and strongly expressed neurotrophic factors, combined BMT and GCSF treatment led to the replacement of G93A microglial cells with BM-derived WT cells. These results indicate combined treatment with BMT and GCSF has potential neuroprotective and angiogenic effects in ALS mice, induced by the replacement of G93A microglial cells with BM-derived WT cells. Furthermore, this is the first report showing the effects of combined BMT and GCSF treatment on blood vessels in ALS.

Growth factors in ischemic stroke

Data from pre-clinical and clinical studies provide evidence that colony-stimulating factors (CSFs) and other growth factors (GFs) can improve stroke outcome by reducing stroke damage through their anti-apoptotic and anti-inflammatory effects, and by promoting angiogenesis and neurogenesis. This review provides a critical and up-to-date literature review on CSF use in stroke. We searched for experimental and clinical studies on haemopoietic GFs such as granulocyte CSF, erythropoietin, granulocyte-macrophage colony-stimulating factor, stem cell factor (SCF), vascular endothelial GF, stromal cell-derived factor-1α and SCF in ischemic stroke. We also considered studies on insulin-like growth factor-1 and neurotrophins. Despite promising results from animal models, the lack of data in human beings hampers efficacy assessments of GFs on stroke outcome. We provide a comprehensive and critical view of the present knowledge about GFs and stroke, and an overview of ongoing and future prospects.

Flt3 ligand synergizes with granulocyte-colony-stimulating factor in bone marrow mobilization to improve functional outcome after spinal cord injury in the rat

BACKGROUND AIMS

The effect of granulocyte-colony-stimulating factor (G-CSF) and/or the cytokine fms-like thyrosin kinase 3 (Flt3) ligand on functional outcome and tissue regeneration was studied in a rat model of spinal cord injury (SCI).

METHODS

Rats with a balloon-induced compression lesion were injected with G-CSF and/or Flt3 ligand to mobilize bone marrow cells. Behavioral tests (Basso-Beattie-Bresnahan and plantar test), blood counts, morphometric evaluation of the white and gray matter, and histology were performed 5 weeks after SCI.

RESULTS

The mobilization of bone marrow cells by G-CSF, Flt3 ligand and their combination improved the motor and sensory performance of rats with SCI, reduced glial scarring, increased axonal sprouting and spared white and gray matter in the lesion. The best results were obtained with a combination of G-CSF and Flt3. G-CSF alone or in combination with Flt3 ligand significantly increased the number of white blood cells, but not red blood cells or hemoglobin content, during and after the time-course of bone marrow stimulation. The combination of factors led to infiltration of the lesion by CD11b(+) cells.

CONCLUSIONS

The observed improvement in behavioral and morphologic parameters and tissue regeneration in animals with SCI treated with a combination of both factors could be associated with a prolonged time-course of mobilization of bone marrow cells. The intravenous administration of G-CSF and/or Flt3 ligand represents a safe and effective treatment modality for SCI.