Effects of granulocyte-colony-stimulating factor on mobilization of bone-marrow-derived stem cells after myocardial infarction in humans

Exposure to acoustic stimuli promotes the development and differentiation of neural stem cells from the cochlear nuclei through the clusterin pathway

Stem cell therapy has attracted widespread attention for a number of diseases. Recently, neural stem cells (NSCs) from the cochlear nuclei have been identified, indicating a potential direction for the treatment of sensorineural hearing loss. Acoustic stimuli play an important role in the development of the auditory system. In this study, we aimed to determine whether acoustic stimuli induce NSC development and differentiation through the upregulation of clusterin (CLU) in NSCs isolated from the cochlear nuclei. To further clarify the underlying mechanisms involved in the development and differentiation of NSCs exposed to acoustic stimuli, we successfully constructed animal models in which was CLU silenced by an intraperitoneal injection of shRNA targeting CLI. As expected, the NSCs from rats treated with LV-CLU shRNA exhibited a lower proliferation ratio when exposed to an augmented acoustic environment (AAE). Furthermore, the inhibition of cell apoptosis induced by exposure to AAE was abrogated after silencing the expression of the CLU gene. During the differentiation of acoustic stimuli-exposed stem cells into neurons, the number of astrocytes was significantly reduced, as evidenced by the expression of the cell markers, microtubule associated protein-2 (MAP-2) and glial fibrillary acidic protein (GFAP), which was markedly inhibited when the CLU gene was silenced. Our results indicate that acoustic stimuli may induce the development and differentiation of NSCs from the cochlear nucleus mainly through the CLU pathway. Our study suggests that CLU may be a novel target for the treatment of sensorineural hearing loss.

Emerging hematological targets and therapy for cardiovascular disease: From bench to bedside

Atherosclerotic cardiovascular disease is the leading cause of death and a major part of its pathophysiology remains obscure. Some hematological targets have been related to the development and clinical outcome of this disease, especially soluble cytokines, leukocytes, red blood cells, hemostatic factors and platelets, and bone-marrow vascular progenitors. These emerging factors may be modulated by current antiatherosclerotic pharmacotherapy, target-designed novel drugs or progenitor cell therapy. The aim of current review article is to comprehensively review the role of these antiatherosclerotic targets and therapy.

Granulocyte colony stimulating factor decreases brain amyloid burden and reverses cognitive impairment in Alzheimer's mice

Granulocyte colony stimulating factor (G-CSF) is a multi-modal hematopoietic growth factor, which also has profound effects on the diseased CNS. G-CSF has been shown to enhance recovery from neurologic deficits in rodent models of ischemia. G-CSF appears to facilitate neuroplastic changes by both mobilization of bone marrow-derived cells and by its direct actions on CNS cells. The overall objective of the study was to determine if G-CSF administration in a mouse model of Alzheimer's disease (AD) (Tg APP/PS1) would impact hippocampal-dependent learning by modifying the underlying disease pathology. A course of s.c. administration of G-CSF for a period of less than three weeks significantly improved cognitive performance, decreased beta-amyloid deposition in hippocampus and entorhinal cortex and augmented total microglial activity. Additionally, G-CSF reduced systemic inflammation indicated by suppression of the production or activity of major pro-inflammatory cytokines in plasma. Improved cognition in AD mice was associated with increased synaptophysin immunostaining in hippocampal CA1 and CA3 regions and augmented neurogenesis, evidenced by increased numbers of calretinin-expressing cells in dentate gyrus. Given that G-CSF is already utilized clinically to safely stimulate hematopoietic stem cell production, these basic research findings will be readily translated into clinical trials to reverse or forestall the progression of dementia in AD. The primary objective of the present study was to determine whether a short course of G-CSF administration would have an impact on the pathological hallmark of AD, the age-dependent accumulation of A beta deposits, in a transgenic mouse model of AD (APP+ PS1; Tg). A second objective was to determine whether such treatment would impact cognitive performance in a hippocampal-dependent memory paradigm. To explain the G-CSF triggered amyloid reduction and associated reversal of cognitive impairment, several mechanisms of action were explored. (1) G-CSF was hypothesized to increase activation of resident microglia and to increase mobilization of marrow-derived microglia. The effect of G-CSF on microglial activation was examined by quantitative measurements of total microglial burden. To determine if G-CSF increased trafficking of marrow-derived microglia into brain, bone marrow-derived green fluorescent protein-expressing (GFP+) microglia were visualized in the brains of chimeric AD mice. (2) To assess the role of immune-modulation in mediating G-CSF effects, a panel of cytokines was measured in both plasma and brain. (3) To test the hypothesis that reduction of A beta deposits can affect synaptic area, quantitative measurement of synaptophysin immunoreactivity in hippocampal CA1 and CA3 sectors was undertaken. (4) To learn whether enhanced hippocampal neurogenesis was induced by G-CSF treatment, numbers of calretinin-expressing cells were determined in dentate gyrus.

Endothelial progenitor cells and their potential clinical implication in cardiovascular disorders

Risk factors associated with cardiovascular diseases reduce the availability of endothelial progenitor cells (EPC) by affecting their mobilization and integration into injured vascular sites. The existence of a bone marrow reservoir of EPC has attracted interest, especially as target for therapeutic intervention in different pathological settings. Among the cardiovascular risk factors, hypertension has been shown to be a strongest predictor of EPC migratory impairment. However, at present, data concerning EPC biology are still limited. In this article we provide an overview of data relevant to their potential clinical implications in cardiovascular disorders. In addition, the recent advances in understanding the role of EPC in the pathophysiology of hypertension are discussed.

Potential use of endothelial progenitor cells for regeneration of the vasculature

Over the past decade, interest has been generated in the study of endothelial progenitor cells (EPCs). EPCs have been studied for their role in endogenous maintenance and for their therapeutic potential in vascular regenerative medicine. Despite their obvious potential in clinical practice, there still remain many controversies regarding how EPCs actually enhance endothelial repair and neovascularization. In addition, because of the limited expansion ability of EPCs, expansion of sufficient EPC populations for therapeutic angiogenesis remains a major task. On the other hand, embryonic stem (ES) cells have an extended self-renewal activity and can be expanded without limit, thus ES-cell-derived endothelial cells could be feasible as a novel cell source for therapeutic angiogenesis. In this review, we discuss recent experimental and clinical findings of EPCs and human ES-cell-derived endothelial cells for the treatment of ischemic cardiovascular diseases.

The potential of hematopoietic growth factors for treatment of Alzheimer's disease: a mini-review

There are no effective interventions that significantly forestall or reverse neurodegeneration and cognitive decline in Alzheimer's disease. In the past decade, the generation of new neurons has been recognized to continue throughout adult life in the brain's neurogenic zones. A major challenge has been to find ways to harness the potential of the brain's own neural stem cells to repair or replace injured and dying neurons. The administration of hematopoietic growth factors or cytokines has been shown to promote brain repair by a number of mechanisms, including increased neurogenesis, anti-apoptosis and increased mobilization of bone marrow-derived microglia into brain. In this light, cytokine treatments may provide a new therapeutic approach for many brain disorders, including neurodegenerative diseases like Alzheimer's disease. In addition, neuronal hematopoietic growth factor receptors provide novel targets for the discovery of peptide-mimetic drugs that can forestall or reverse the pathological progression of Alzheimer's disease.

Endothelial progenitor cell therapy for the treatment of coronary disease, acute MI, and pulmonary arterial hypertension: current perspectives

Since their identification in 1997, bone marrow derived endothelial progenitor cells (EPCs) have been studied for their role in the endogenous maintenance and repair of endothelium and their potential regenerative capacity beyond the endothelium. In particular, EPCs have been tested in cell therapy approaches with the aim of developing novel therapies for conditions currently lacking effective treatment options. In this review, we discuss the scientific background and clinical experience using EPC delivery or mobilization for the treatment of post-angioplasty restenosis, acute myocardial infarction and pulmonary arterial hypertension. Although these approaches are safe, efficacy has yet to be proven in large randomized clinical trials. Unfortunately, the biology of EPCs is still poorly understood. The success of future clinical trials depends on a better understanding of EPC biology and intelligent design.

A meta-analysis of stem cell mobilization by granulocyte colony-stimulating factor in the treatment of acute myocardial infarction

OBJECTIVE

This project was aimed at evaluating the safety and efficacy of granulocyte colony-stimulating factor (G-CSF) as an adjunctive therapy to the standard therapy [percutaneous coronary interventions (PCI) and conventional medication] after acute myocardial infarction (AMI).

METHODS

A meta-analysis of randomized controlled trials (RCTs) of G-CSF as an adjunctive therapy to standard therapy versus standard therapy was performed. The endpoints were defined as (1) target-vessel restenosis, (2) cumulative cardiac events (CCEs) that were a combined endpoint of all-cause deaths, reinfarction, and target-vessel revascularization, and (3) the changes in left ventricular ejection fraction (LVEF) from baseline to follow-up.

RESULTS

320 patients were involved in 6 RCTs, of whom 160 were randomized to the G-CSF group and 160 to the control group. The follow-up period was 6.17 +/- 3.49 months. There was no significant difference in the risk of target-vessel restenosis (P = 0.90) or CCEs (P = 0.59) between the two groups. When a pooled analysis of the changes in LVEF was performed with fixed-model effect, a significant heterogeneity was observed (P < 0.00001). The pooled analysis was thus conducted with random-model effect and did not show a significant improvement as compared to the control group (P = 0.34). A similar result was found in the sensitivity analysis based on five placebo-controlled trials involving 270 patients (P = 0.94).

CONCLUSIONS

G-CSF as an adjunctive therapy to standard therapy for patients with AMI may be safe. However, there is not much supporting evidence that this treatment could further improve LVEF. Since there are relatively few RCTs that meet the inclusion criteria and are heterogeneous in design, further research is required.

Expression of granulocyte-colony-stimulating factor and its receptor in human Ewing sarcoma cells and patient tumor specimens: potential consequences of granulocyte-colony-stimulating factor administration

BACKGROUND

Ewing sarcoma (ES) is a highly vascular malignancy. It has been demonstrated that both angiogenesis and vasculogenesis contribute to the growth of ES tumors. Granulocyte-colony-stimulating factor (G-CSF), a cytokine known to stimulate bone marrow (BM) stem cell production and angiogenesis, is routinely administered to ES patients after chemotherapy. Whether ES cells and patient tumor samples express G-CSF and its receptor (G-CSFR) and whether treatment with this factor enhances tumor growth was examined.

METHODS

Human ES cell lines were analyzed for expression of G-CSF and G-CSFR in vitro and in vivo. Sixty-eight paraffin-embedded and 15 frozen tumor specimens from patients with ES were also evaluated for the presence of G-CSF and G-CSFR. The in vivo effect of G-CSF on angiogenesis and BM cell migration was determined. Using a TC/7-1 human ES mouse model, the effect of G-CSF administration on ES tumors was investigated.

RESULTS

G-CSF and G-CSFR protein and RNA expression was identified in all ES cell lines and patient samples analyzed. In addition, G-CSF was found to stimulate angiogenesis and BM cell migration in vivo. Tumor growth was found to be significantly increased in mice treated with G-CSF. The average tumor volume for the group treated with G-CSF was 1218 mm(3) compared with 577 mm(3) for the control group (P = .006).

CONCLUSIONS

The findings that ES cells and patient tumors expressed both G-CSF and its receptor in vitro and in vivo and that the administration of G-CSF promoted tumor growth in vivo suggest that the potential consequences of G-CSF administration should be investigated further.

Impact of intracoronary cell therapy on left ventricular function in the setting of acute myocardial infarction: a collaborative systematic review and meta-analysis of controlled clinical trials

OBJECTIVES

We aimed to perform a meta-analysis of clinical trials on intracoronary cell therapy after acute myocardial infarction (AMI).

BACKGROUND

Intracoronary cell therapy continues to be evaluated in the setting of AMI with variable impact on left ventricular ejection fraction (LVEF).

METHODS

We searched the CENTRAL, mRCT, and PubMed databases for controlled trials reporting on intracoronary cell therapy performed in patients with a recent AMI (< or =14 days), revascularized percutaneously, with follow-up of > or =3 months. The primary end point was change in LVEF, and secondary end points were changes in infarct size, cardiac dimensions, and dichotomous clinical outcomes.

RESULTS

Ten studies were retrieved (698 patients, median follow-up 6 months), and pooling was performed with random effect. Subjects that received intracoronary cell therapy had a significant improvement in LVEF (3.0% increase [95% confidence interval (CI) 1.9 to 4.1]; p < 0.001), as well as a reduction in infarct size (-5.6% [95% CI -8.7 to -2.5]; p < 0.001) and end-systolic volume (-7.4 ml [95% CI -12.2 to -2.7]; p = 0.002), and a trend toward reduced end-diastolic volume (-4.6 ml [95% CI -10.4 to 1.1]; p = 0.11). Intracoronary cell therapy was also associated with a nominally significant reduction in recurrent AMI (p = 0.04) and with trends toward reduced death, rehospitalization for heart failure, and repeat revascularization. Meta-regression suggested the existence of a dose-response association between injected cell volume and LVEF change (p = 0.066).

CONCLUSIONS

Intracoronary cell therapy following percutaneous coronary intervention for AMI appears to provide statistically and clinically relevant benefits on cardiac function and remodeling. These data confirm the beneficial impact of this novel therapy and support further multicenter randomized trials targeted to address the impact of intracoronary cell therapy on overall and event-free long-term survival.

G-CSF therapy for acute myocardial infarction

Granulocyte-colony-stimulating factor (G-CSF) has recently been shown to have various effects besides promoting the proliferation and differentiation of myeloid progenitor cells, including the mobilization of bone marrow stem cells and the regeneration infarcted hearts in mice. Recent animal studies have also revealed that G-CSF activates multiple signaling pathways, such as Akt and also the Janus family kinase-2 and signal transducer and activation of transcription-3 (Jak2-STAT3) pathway, in cardiac myocytes. It prevents left ventricular remodeling after myocardial infarction by decreasing cardiomyocyte death and by increasing the number of blood vessels, suggesting the importance of direct actions of G-CSF on the myocardium rather than through mobilization and differentiation of stem cells. Several clinical trials have been performed to study the efficacy of G-CSF therapy in patients with acute myocardial infarction but the results remain controversial because the protocols followed varied between the trials.

G-CSF and HGF: combination of vasculogenesis and angiogenesis synergistically improves recovery in murine hind limb ischemia

Granulocyte colony-stimulating factor (G-CSF) is known to mobilize bone marrow stem cells into the peripheral circulation. This study was designed to investigate whether G-CSF by itself or in combination with hepatocyte growth factor (HGF) can promote vasculogenesis and angiogenesis in murine hind limb ischemia. Hind limb ischemia was induced in BALB/c nude or C57/BL6 mice that received bone marrow transplantation from green fluorescent protein (GFP)-transgenic mice. In the HGF group, hHGF expression plasmid was injected into the ischemic muscles. In the G-CSF group, G-CSF was administered subcutaneously for 10 days. The G-CSF+HGF group was concomitantly treated with G-CSF and HGF, and the control group received no treatment. All effects were confirmed at 4 weeks. The G-CSF+HGF group had a higher laser Doppler blood perfusion index, higher microvessel density, and a lower incidence of hind limb necrosis than the other groups. Confocal laser microscopy revealed that a number of GFP-positive cells infiltrated to the vasculature of the ischemic area. Some of the GFP positive cells were clearly co-immunostained with alpha-smooth muscle actin as well as von Willebrand factor. G-CSF-mobilized stem cells co-expressed CD49d and CD34, which would have promoted their adhesion to cells in the ischemic muscle that expressed HGF-induced vascular cell adhesion molecule-1. The combination of G-CSF and HGF had a significant synergistic effect, suggesting that the combination of mobilization of stem cells from bone marrow to peripheral circulation and their recruitment to the ischemic area might potentiate angiogenesis and vasculogenesis.

Endothelial progenitor cells in health and atherosclerotic disease

Cardiovascular disease is associated with damage of the endothelial monolayer leading to endothelial dysfunction and atherosclerosis. A growing body of evidence suggests that circulating endothelial progenitor cells play an important role in endothelial cell regeneration. In this review we discuss the evolving role of stem- and progenitor cells in the maintenance of the vascular wall focusing on new pathophysiological concepts of endothelial cell regeneration. We discuss new insights into vascular stem cell biology derived from experimental and clinical studies.

Potential Hazards and Technical Considerations Associated With Myocardial Cell Transplantation Protocols for Ischemic Myocardial Syndrome

Cell transplantation has recently emerged as a promising therapeutic approach to ischemic cardiomyopathy syndromes. Clinical studies suggest important benefits, including improved myocardial perfusion and function. The safety profile so far seems to be high overall, although the technique may harbor several adverse effects, such as ventricular arrhythmia, acceleration of atherosclerosis or restenosis, and induction of ischemic events. Multiple factors may affect the safety of cell infusion into the diseased heart, including the mode of delivery, the type of cells injected, compound characterization, and the heart status, function, and arrhythmogenic potential. Also, any adjunctive treatment used to enhance cellular homing and/or transdifferentiation increases the likelihood of unexpected local or systemic toxicity or side effects. In the present review, we discuss the potential hazards of this novel treatment and its relationship to technical considerations.