Effect of erythropoietin on level of circulating endothelial progenitor cells and outcome in patients after acute ischemic stroke

Cellular and molecular mechanisms in vascular repair after traumatic brain injury: a narrative review

Traumatic brain injury (TBI) disrupts normal brain function and is associated with high morbidity and fatality rates. TBI is characterized as mild, moderate or severe depending on its severity. The damage may be transient and limited to the dura matter, with only subtle changes in cerebral parenchyma, or life-threatening with obvious focal contusions, hematomas and edema. Blood vessels are often injured in TBI. Even in mild TBI, dysfunctional cerebral vascular repair may result in prolonged symptoms and poor outcomes. Various distinct types of cells participate in vascular repair after TBI. A better understanding of the cellular response and function in vascular repair can facilitate the development of new therapeutic strategies. In this review, we analyzed the mechanism of cerebrovascular impairment and the repercussions following various forms of TBI. We then discussed the role of distinct cell types in the repair of meningeal and parenchyma vasculature following TBI, including endothelial cells, endothelial progenitor cells, pericytes, glial cells (astrocytes and microglia), neurons, myeloid cells (macrophages and monocytes) and meningeal lymphatic endothelial cells. Finally, possible treatment techniques targeting these unique cell types for vascular repair after TBI are discussed.

Beyond brain injury biomarkers: chemoattractants and circulating progenitor cells as biomarkers of endogenous rehabilitation effort in preterm neonates with encephalopathy

Introduction

Preclinical work and studies in adults have shown that endogenous regeneration efforts that involve mobilization of progenitor cells take place after brain injury. However, kinetics of endogenous circulating progenitor cells (CPCs) in preterm neonates is not well described, particularly their possible role regarding brain injury and regeneration. We aimed to assess the kinetics of CPCs in neonates with encephalopathy of prematurity in relation to brain injury biomarkers, chemoattractants and relevant antenatal and postanal clinical factors, in an effort to outline the related pathophysiology.

Materials and methods

47 preterm neonates (of 28-33 weeks GA) were enrolled: 31 newborns with no or minimal brain injury (grade I IVH) and 16 prematures with encephalopathy (grade III or IV IVH, PVL or infarct). Peripheral blood samples obtained on days 1, 3, 9, 18 and 45 after birth were analyzed using flow cytometry, focusing on EPCs (early and late Endothelial Progenitor Cells), HSCs (Hematopoietic Stem Cells) and VSELs (Very Small Embryonic-Like Stem Cells). At the same time-points serum levels of S100B, Neuron-specific Enolase (NSE), Erythropoietin (EPO), Insulin-like growth factor-1 (IGF-1) and SDF-1 were also measured. Neonates were assessed postnatally with brain MRI, and with Bayley III developmental test at 2 years of corrected age.

Results

Preterms with brain injury proved to have significant increase of S100B and NSE, followed by increase of EPO and enhanced mobilization mainly of HSCs, eEPCs and lEPCs. IGF-1 was rather decreased in this group of neonates. IGF-1 and most CPCs were intense decreased in cases of antenatal or postnatal inflammation. S100B and NSE correlated with neuroimaging and language scale in Bayley III test, providing good prognostic ability.

Conclusion

The observed pattern of CPCs' mobilization and its association with neurotrophic factors following preterm brain injury indicate the existence of an endogenous brain regeneration process. Kinetics of different biomarkers and associations with clinical factors contribute to the understanding of the related pathophysiology and might help to early discriminate neonates with adverse outcome. Timely appropriate enhancement of the endogenous regeneration effort, when it is suppressed and insufficient, using neurotrophic factors and exogenous progenitor cells might be a powerful therapeutic strategy in the future to restore brain damage and improve the neurodevelopmental outcome in premature infants with brain injury.

Asialo-rhuEPO as a Potential Neuroprotectant for Ischemic Stroke Treatment

Neuroprotective drugs to protect the brain against cerebral ischemia and reperfusion (I/R) injury are urgently needed. Mammalian cell-produced recombinant human erythropoietin (rhuEPOM) has been demonstrated to have excellent neuroprotective functions in preclinical studies, but its neuroprotective properties could not be consistently translated in clinical trials. The clinical failure of rhuEPOM was thought to be mainly due to its erythropoietic activity-associated side effects. To exploit its tissue-protective property, various EPO derivatives with tissue-protective function only have been developed. Among them, asialo-rhuEPO, lacking terminal sialic acid residues, was shown to be neuroprotective but non-erythropoietic. Asialo-rhuEPO can be prepared by enzymatic removal of sialic acid residues from rhuEPOM (asialo-rhuEPOE) or by expressing human EPO gene in glycoengineered transgenic plants (asialo-rhuEPOP). Both types of asialo-rhuEPO, like rhuEPOM, displayed excellent neuroprotective effects by regulating multiple cellular pathways in cerebral I/R animal models. In this review, we describe the structure and properties of EPO and asialo-rhuEPO, summarize the progress on neuroprotective studies of asialo-rhuEPO and rhuEPOM, discuss potential reasons for the clinical failure of rhuEPOM with acute ischemic stroke patients, and advocate future studies needed to develop asialo-rhuEPO as a multimodal neuroprotectant for ischemic stroke treatment.

Correlation between Serum Erythropoietin and Cerebral Collateral Flow in Acute Ischemic Stroke Patient

BACKGROUND

Erythropoietin (EPO), which is associated with anemia, exerts neuroprotective effects in ischemic stroke. In cases of stenosis or narrowing of the main cerebral blood vessel, the prognosis is favorable if collateral blood circulation is well developed in acute stroke. Several studies have investigated the relationship between EPO administration and stroke outcomes. The present study investigated the correlation between serum EPO level and cerebral collateral circulation, which could result in favorable clinical outcomes.

METHODS

The study subjects were patients diagnosed with acute ischemic stroke who underwent initial brain magnetic resonance imaging between January 2020 and March 2022. Following brain computed tomography perfusion for collateral flow, serum EPO levels were measured. Collaterals were assessed according to the Mass system and divided into good collateral (GC) or poor collateral (PC) groups. Serum EPO levels were determined using a chemiluminescence immunoassay method. A correlation coefficient analysis was conducted to determine the correlation between serum EPO levels and GC. A receiver operating characteristic curve analysis determined the cutoff value of EPO for GC.

RESULTS

Serum EPO levels were significantly higher in the GC than that in the PC group (P<0.05). The cut-off level of serum EPO for a good outcome was 9.1 mIU/mL.

CONCLUSION

A high serum EPO (>9.1 mIU/mL) could be a marker of GC in patients with acute ischemic stroke that predicts good clinical outcomes.

OUP accepted manuscript

Fetal growth restriction (FGR) occurs when a fetus is unable to grow normally due to inadequate nutrient and oxygen supply from the placenta. Children born with FGR are at high risk of lifelong adverse neurodevelopmental outcomes, such as cerebral palsy, behavioral issues, and learning and attention difficulties. Unfortunately, there is no treatment to protect the FGR newborn from these adverse neurological outcomes. Chronic inflammation and vascular disruption are prevalent in the brains of FGR neonates and therefore targeted treatments may be key to neuroprotection. Tissue repair and regeneration via stem cell therapies have emerged as a potential clinical intervention for FGR babies at risk for neurological impairment and long-term disability. This review discusses the advancement of research into stem cell therapy for treating neurological diseases and how this may be extended for use in the FGR newborn. Leading preclinical studies using stem cell therapies in FGR animal models will be highlighted and the near-term steps that need to be taken for the development of future clinical trials.

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.

Neovascularization and tissue regeneration by endothelial progenitor cells in ischemic stroke

Endothelial progenitor cells (EPCs) are immature endothelial cells (ECs) capable of proliferating and differentiating into mature ECs. These progenitor cells migrate from bone marrow (BM) after vascular injury to ischemic areas, where they participate in the repair of injured endothelium and new blood vessel formation. EPCs also secrete a series of protective cytokines and growth factors that support cell survival and tissue regeneration. Thus, EPCs provide novel and promising potential therapies to treat vascular disease, including ischemic stroke. However, EPCs are tightly regulated during the process of vascular repair and regeneration by numerous endogenous cytokines that are associated closely with the therapeutic efficacy of the progenitor cells. The regenerative capacity of EPCs also is affected by a range of exogenous factors and drugs as well as vascular risk factors. Understanding the functional properties of EPCs and the factors related to their regenerative capacity will facilitate better use of these progenitor cells in treating vascular disease. Here, we review the current knowledge of EPCs in cerebral neovascularization and tissue regeneration after cerebral ischemia and the factors associated with their regenerative function to better understand the underlying mechanisms and provide more effective strategies for the use of EPCs in treating ischemic stroke.

Principles of Neural Repair and Their Application to Stroke Recovery Trials

Neural repair is the underlying therapeutic strategy for many treatments currently under investigation to improve recovery after stroke. Repair-based therapies are distinct from acute stroke strategies: instead of salvaging threatened brain tissue, the goal is to improve behavioral outcomes on the basis of experience-dependent brain plasticity. Furthermore, timing, concomitant behavioral experiences, modality specific outcome measures, and careful patient selection are fundamental concepts for stroke recovery trials that can be deduced from principles of neural repair. Here we discuss core principles of neural repair and their implications for stroke recovery trials, highlighting related issues from key studies in humans. Research suggests a future in which neural repair therapies are personalized based on measures of brain structure and function, genetics, and lifestyle factors.

The Protective and Reparative Role of Colony-Stimulating Factors in the Brain with Cerebral Ischemia/Reperfusion Injury

Stroke is a debilitating disease and has the ability to culminate in devastating clinical outcomes. Ischemic stroke followed by reperfusion entrains cerebral ischemia/reperfusion (I/R) injury, which is a complex pathological process and is associated with serious clinical manifestations. Therefore, the development of a robust and effective poststroke therapy is crucial. Granulocyte colony-stimulating factor (GCSF) and erythropoietin (EPO), originally discovered as hematopoietic growth factors, are versatile and have transcended beyond their traditional role of orchestrating the proliferation, differentiation, and survival of hematopoietic progenitors to one that fosters brain protection/neuroregeneration. The clinical indication regarding GCSF and EPO as an auspicious therapeutic strategy is conferred in a plethora of illnesses, including anemia and neutropenia. EPO and GCSF alleviate cerebral I/R injury through a multitude of mechanisms, involving antiapoptotic, anti-inflammatory, antioxidant, neurogenic, and angiogenic effects. Despite bolstering evidence from preclinical studies, the multiple brain protective modalities of GCSF and EPO failed to translate in clinical trials and thereby raises several questions. The present review comprehensively compiles and discusses key findings from in vitro, in vivo, and clinical data pertaining to the administration of EPO, GCSF, and other drugs, which alter levels of colony-stimulating factor (CSF) in the brain following cerebral I/R injury, and elaborates on the contributing factors, which led to the lost in translation of CSFs from bench to bedside. Any controversial findings are discussed to enable a clear overview of the role of EPO and GCSF as robust and effective candidates for poststroke therapy.

Potential Efficacy of Erythropoietin on Reducing the Risk of Mortality in Patients with Traumatic Brain Injury: A Systematic Review and Meta-Analysis

Objective

The objective of this study is to assess the effectiveness of erythropoietin (EPO) on mortality, neurological outcomes, and adverse event in the treatment of traumatic brain injury (TBI).

Methods

We searched databases including PubMed, OVID, and the Cochrane Library from inception until October 18, 2019 for randomized controlled trials (RCTs) to compare EPO treatment group and placebo in patients with TBI. Two authors independently processed the data and evaluated the quality of inclusion studies. Statistical analysis was performed with heterogeneity test with I ² and chi-square tests. We summarized the mortality, prognosis of neurological function, and deep vein thrombosis (DVT) outcomes and presented as risk ratio (RR) or risk difference (RD) with a 95% CI.

Results

Seven RCTs accounting for 1180 patients were included after meeting the inclusion criteria. Compared with placebo, the overall mortality of EPO-treated patients was significantly reduced (RR 0.68 [95% CI 0.50-0.93]; p = 0.02). EPO therapy did not improve neurological prognosis (RR 1.21 [95% CI 0.93-1.15]; p = 0.16) or increase the occurrence of DVT (RR 0.83 [95% CI 0.61-1.13]; p = 0.242), which showed no significant difference.

Conclusions

The results showed that the administration of EPO may reduce the risk of mortality without enhancing the occurrence of DVT in TBI patients. However, the effect of EPO on neurological outcome remains indistinct. Through subgroup analysis, we demonstrated that the dose of EPO may be a potential factor affecting the heterogeneity in neurological function and that the follow-up duration may influence the stability of the result.

Insights into Potential Targets for Therapeutic Intervention in Epilepsy

Epilepsy is a chronic brain disease that affects approximately 65 million people worldwide. However, despite the continuous development of antiepileptic drugs, over 30% patients with epilepsy progress to drug-resistant epilepsy. For this reason, it is a high priority objective in preclinical research to find novel therapeutic targets and to develop effective drugs that prevent or reverse the molecular mechanisms underlying epilepsy progression. Among these potential therapeutic targets, we highlight currently available information involving signaling pathways (Wnt/β-catenin, Mammalian Target of Rapamycin (mTOR) signaling and zinc signaling), enzymes (carbonic anhydrase), proteins (erythropoietin, copine 6 and complement system), channels (Transient Receptor Potential Vanilloid Type 1 (TRPV1) channel) and receptors (galanin and melatonin receptors). All of them have demonstrated a certain degree of efficacy not only in controlling seizures but also in displaying neuroprotective activity and in modifying the progression of epilepsy. Although some research with these specific targets has been done in relation with epilepsy, they have not been fully explored as potential therapeutic targets that could help address the unsolved issue of drug-resistant epilepsy and develop new antiseizure therapies for the treatment of epilepsy.

Cerebro-renal interaction and stroke

Stroke is an event causing a disturbance in cerebral function leading to death and disability worldwide. Both acute kidney injury and chronic kidney disease (CKD) are associated with an increased risk of stroke and cerebrovascular events. The underlying mechanistic approach between impaired renal function and stroke is limitedly explored and has attracted researchers to learn more for developing therapeutic intervention. Common risk factors such as hypertension, hyperphosphatemia, atrial fibrillation, arteriosclerosis, hyperhomocysteinemia, blood-brain barrier disruption, inflammation, etc. are observed in the general population, but are high in renal failure patients. Also, risk factors like bone mineral metabolism, uremic toxins, and anemia, along with the process of dialysis in CKD patients, eventually increases the risk of stroke. Therefore, early detection of risks associated with stroke in CKD is imperative, which may decrease the mortality associated with it. This review highlights mechanisms by which kidney dysfunction can lead to cerebrovascular events and increase the risk of stroke in renal impairment.

Biomimetic 3D Models for Investigating the Role of Monocytes and Macrophages in Atherosclerosis

Atherosclerosis, the inflammation of artery walls due to the accumulation of lipids, is the most common underlying cause for cardiovascular diseases. Monocytes and macrophages are major cells that contribute to the initiation and progression of atherosclerotic plaques. During this process, an accumulation of LDL-laden macrophages (foam cells) and an alteration in the extracellular matrix (ECM) organization leads to a local vessel stiffening. Current in vitro models are carried out onto two-dimensional tissue culture plastic and cannot replicate the relevant microenvironments. To bridge the gap between in vitro and in vivo conditions, we utilized three-dimensional (3D) collagen matrices that allowed us to mimic the ECM stiffening during atherosclerosis by increasing collagen density. First, human monocytic THP-1 cells were embedded into 3D collagen matrices reconstituted at low and high density. Cells were subsequently differentiated into uncommitted macrophages (M0) and further activated into pro- (M1) and anti-inflammatory (M2) phenotypes. In order to mimic atherosclerotic conditions, cells were cultured in the presence of oxidized LDL (oxLDL) and analyzed in terms of oxLDL uptake capability and relevant receptors along with their cytokine secretomes. Although oxLDL uptake and larger lipid size could be observed in macrophages in a matrix dependent manner, monocytes showed higher numbers of oxLDL uptake cells. By analyzing major oxLDL uptake receptors, both monocytes and macrophages expressed lectin-like oxidized low-density lipoprotein receptor-1 (LOX1), while enhanced expression of scavenger receptor CD36 could be observed only in M2. Notably, by analyzing the secretome of macrophages exposed to oxLDL, we demonstrated that the cells could, in fact, secrete adipokines and growth factors in distinct patterns. Besides, oxLDL appeared to up-regulate MHCII expression in all cells, while an up-regulation of CD68, a pan-macrophage marker, was found only in monocytes, suggesting a possible differentiation of monocytes into a pro-inflammatory macrophage. Overall, our work demonstrated that collagen density in the plaque could be one of the major factors driving atherosclerotic progression via modulation of monocyte and macrophages behaviors.

Monoclonal antibody as an emerging therapy for acute ischemic stroke

Acute ischemic stroke (AIS) is the 5^th leading cause of death and the leading cause of neurological disability in the United States. The oxygen and glucose deprivation associated with AIS not only leads to neuronal cell death, but also increases the inflammatory response, therefore decreasing the functional outcome of the brain. The only pharmacological intervention approved by the US Federal Food and Drug Administration for treatment of AIS is tissue plasminogen activator (t-PA), however, such treatment can only be given within 4.5 hours of the onset of stroke-like symptoms. This narrow time-range limits its therapeutic application. Administrating t-PA outside of the therapeutic window may induce detrimental rather than beneficial effects to stroke patients. In order to reduce the infarct volume of an AIS while increasing the time period for treatment, new treatments are essential. Emerging monoclonal antibody (mAb) therapies reveal great potential by targeting signaling pathways activated after an AIS. With successful application of mAb in the treatment of cancer, other therapeutic uses for mAb are currently being evaluated. In this review, we will focus on recent advances on AIS therapy by using mAb that targets the signaling cascades and endogenous molecules such as inflammation, growth factors, acid-sensing ion channels, and N-methyl-D-aspartate receptors. Therefore, developing specific mAb to target the signaling pathways of ischemic brain injury will benefit patients being treated for an AIS.

The combination of G9a histone methyltransferase inhibitors with erythropoietin protects heart against damage from acute myocardial infarction

BACKGROUND

This study tested the hypothesis that combined histone methyltransferase G9a inhibitor (i.e., UNC0638) and erythropoietin (EPO) was superior to either one alone for protecting myocardium from acute myocardial infarction (AMI) damage.

METHODS AND RESULTS

Adult-male SD rats (n=30) were equally categorized into group 1 (sham-operated control), group 2 (AMI), group 3 (AMI-EPO/1000 IU/kg, I.M./3 h after AMI), group 4 (AMI- UNC0638/5 mg/kg I.P./3 h after AMI) and group 5 [AMI-UNC0638-EPO 3 h after AMI] treatment. Animals were euthanized at day 21 after AMI induction. By day 21, left-ventricular-ejection-fraction (LVEF) was highest in group 1, lowest in group 2, significantly higher in group 5 than in groups 3 and 4, but no difference between the latter two groups (all P<0.0001). The protein expressions of inflammatory (MMP-2/MM-9), fibrotic (fibronectin/Smad3/TGF-ß), apoptotic/DNA-damaged (caspas-3/PARP/γ-H2AX), cell-stress response (HIF-1α/p-Akt/p-mTOR) and autophagic (beclin-1/ratio of LC3B-II to LC3B-I) biomarkers exhibited an opposite pattern, whereas the protein expressions of endothelial integrity (CD31/vWF) and anti-oxidant (SIRT1/SIRT3) exhibited an identical pattern of LVEF among the five groups (all P<0.0001). The protein expressions (SDF-1α/VEGF/CXCR4) and cellular expressions (C-kit/CD31+//Sca-1/CD31+//KDR/CD34+) of angiogenesis biomarkers were significantly progressively increased from groups 1 to 5 (all P<0.0001). The infarction/fibrotic areas, myocyte size and number of G9a cells exhibited an opposite pattern, whereas the small-vessel density displayed an identical trend of LVEF among the groups (all P<0.0001). Flow cytometric analysis showed cellular levels of inflammation (Ly6G+/MPO+/CD11b/c+), oxidative-stress (DCFDA+) and apoptosis (early+/late+) exhibited an opposite pattern to LVEF among the groups (all P<0.0001).

CONCLUSION

EPO-BIX01294 effectively protected myocardium against AMI-induced damage.

Intra-carotid arterial transfusion of circulatory-derived autologous endothelial progenitor cells in rodent after ischemic stroke-evaluating the impact of therapeutic time points on prognostic outcomes

Background

This study tested the optimal time point for left intra-carotid arterial (LICA) administration of circulatory-derived autologous endothelial progenitor cells (EPCs) for improving the outcome in rat after acute ischemic stroke (IS).

Methods and results

Adult male SD rats (n = 70) were equally categorized into group 1 (sham-operated control), group 2 (IS), group 3 (IS+EPCs/1.2 × 10⁶ cells/by LICA administration 3 h after IS), group 4 (IS+EPCs/LICA administration post-day-3 IS), group 5 (IS+EPCs/LICA administration post-day-7 IS), group 6 (IS+EPCs/LICA administration post-day-14 IS), and group 7 (IS+EPCs/LICA administration post-day-28 IS). The brain infarct volume (BIV) (at day 60/MRI) was lowest in group 1, highest in group 2, and significantly progressively increased from groups 3 to 7, whereas among the IS animals, the neurological function was significantly preserved in groups 3 to 6 than in groups 2 and 7 post-day-60 IS (all P < 0.0001). By day 60, the endothelial cell markers at protein and cellular levels and number of small vessels exhibited an opposite pattern of BIV among the groups (all P < 0.0001). The protein and cellular levels of inflammation, and protein levels of oxidative stress, autophagy, and apoptosis were highest in group 2, lowest in group 1, and progressively increased from groups 3 to 7 (all P < 0.0001). The angiogenesis biomarkers at protein and cellular levels were significantly progressively increased from groups 1 to 3, then significantly progressively decreased from groups 4 to 7 (all P < 0.0001).

Conclusion

Early EPC administration provided better benefits on improving functional/image/molecular-cellular outcomes after acute IS in rat.

Elevated Inflammatory Parameter Levels Negatively Impact Populations of Circulating Stem Cells (CD133+), Early Endothelial Progenitor Cells (CD133+/VEGFR2+), and Fibroblast Growth Factor in Stroke Patients

BACKGROUND

Endothelial Progenitor Cells (EPCs) are important players in neovascularization, mobilized through signalling by Angiogenic Growth Factors (AGFs) such as Vascular Endothelial Growth Factor (VEGF) and fibroblast growth factor (FGF). In vitro, inflammatory parameters impair the function and influence of EPCs on AGFs. However, this connection is not clear in vivo. To understand the mechanisms of augmented arteriogenesis and angiogenesis in acute ischemic stroke (AIS) patients, we investigated whether circulating stem cells (CD133+), early endothelial progenitor cells (CD133+/VEGFR2+), and endothelial cells (ECs; CD34¯/CD133¯/VEGFR2+) were increasingly mobilized during AIS, and whether there were correlations between EPC levels, growth factor levels and inflammatory parameters.

METHODS

Data on demographics, classical vascular risk factors, neurological deficit information (assessed using the National Institutes of Health Stroke Scale), and treatment were collected from 43 consecutive AIS patients (group I). Risk factor control patients (group II) included 22 nonstroke subjects matched by age, gender, and traditional vascular risk factors. EPCs were measured by flow cytometry and the populations of circulating stem cells (CD133+), early EPCs (CD133+/VEGFR2+), and ECs (CD34¯/CD133¯/VEGFR2+) were analysed. Correlations between EPC levels and VEGF and FGF vascular growth factor levels as well as the influence of inflammatory parameters on EPCs and AGFs were assessed.

RESULTS

Patient ages ranged from 54 to 92 years (mean age 75.2 ± 11.3 years). The number of circulating CD34¯/CD133¯/VEGF-R2+ cells was significantly higher in AIS patients than in control patients (p < 0.05). VEGF plasma levels were also significantly higher in AIS patients compared to control patients on day 7 (p < 0.05). FGF plasma levels in patients with AIS were significantly higher than those in the control group on day 3 (p < 0.05). There were no correlations between increased VEGF and FGF levels and the number of CD133+, CD133+/VEGFR2+, or CD34¯/CD133¯/VEGFR2+ cells. Leukocyte levels, FGF plasma levels, and the number of early EPCs were negatively correlated on day 3. High sensitivity C-reactive protein levels and the number of CD133+ and CD133+/VEGFR2+ cells were negatively correlated on day 7. In addition, there was a negative correlation between fibrinogen levels and FGF plasma levels as well as the number of early EPCs (CD133+/VEGFR2+).

CONCLUSION

AIS patients exhibited increased numbers of early EPCs (CD133+/VEGFR2+) and AGF (VEGF and FGF) levels. A negative correlation between inflammatory parameters and AGFs and EPCs indicated the unfavourable influence of inflammatory factors on EPC differentiation and survival. Moreover, these correlations represented an important mechanism linking inflammation to vascular disease.

Clinical significance of endothelial progenitor cells in patients with liver cirrhosis with or without hepatocellular carcinoma

BACKGROUND AND OBJECTIVE

The role of endothelial progenitor cells in patients with cirrhosis has seldom been investigated. This study was conducted to assess the clinical significance of circulating endothelial progenitor cells in patients with liver cirrhosis with or without hepatocellular carcinoma.

METHODS

A blood sample was collected once from patients with cirrhosis alone (n = 34) or cirrhosis and hepatocellular carcinoma (n = 46) and healthy controls (n = 27) for assessing levels of endothelial progenitor cells and vascular endothelial growth factor. Blood cells staining positive for CD34/CD133/KDR using flow cytometry were characterized as endothelial progenitor cells. Plasma vascular endothelial growth factor was quantified by ELISA.

RESULTS

The levels of CD34/KDR-positive endothelial progenitor cells, CD133/KDR-positive endothelial progenitor cells, and vascular endothelial growth factor were higher in patients with cirrhosis ± hepatocellular carcinoma than in healthy controls (P = 0.017, P < 0.001 and P < 0.001, respectively). The levels of endothelial progenitor cells and vascular endothelial growth factor did not show statistical difference according to Child-Turcotte-Pugh class. There was a moderately significant correlation between vascular endothelial growth factor levels and hepatocellular carcinoma stage (ρ = 0.464, P = 0.001). Smoking, ascites, and portal vein thrombosis were independently related to lower levels of circulating CD34/KDR-positive endothelial progenitor cells, higher levels of CD133/KDR-positive endothelial progenitor cells, and higher levels of vascular endothelial growth factor, respectively (P = 0.041, P = 0.023, and P < 0.001, respectively).

CONCLUSION

Circulating endothelial progenitor cells and plasma vascular endothelial growth factor levels were higher in patients with liver cirrhosis ± hepatocellular carcinoma compared to healthy controls. The increase in endothelial progenitor cells and vascular endothelial growth factor may have a possible role in the development of complications, especially ascites and portal vein thrombosis, or in progression of hepatocellular carcinoma.

Dexamethasone impairs neurofunctional recovery in rats following traumatic brain injury by reducing circulating endothelial progenitor cells and angiogenesis

The administration of glucocorticoids (GCs) after traumatic brain injury (TBI) is controversial. Clinical evidence reveals the deleterious effects of GCs, but the mechanism remains unclear. Previous studies indicate that GCs impair wound healing by affecting endothelial progenitor cell (EPC) function and inhibiting angiogenesis after skin injury. Thus, we hypothesize that the central deleterious effect of GCs is associated with reduced EPCs and angiogenesis after TBI. Using a controlled cortical impact model, we examined the dynamic changes in circulating EPCs and in the regional microcirculation within 14 days of TBI by flow cytometry analysis and contrast-enhanced ultrasound, respectively. The modified neurological severity score (mNSS) and Morris water maze assay were used to assess neurological recovery. Angiogenesis and hippocampal neuron counts were assessed using immunohistochemistry analysis and hematoxylin and eosin staining 14 days after TBI. Compared with the TBI control group, dexamethasone treatment significantly reduced the number of circulating EPCs on days 1, 3, 7 and 14 (P < 0.05); decreased the number of CD31+ cells, the peak intensity and the number of hippocampal neurons on day 14 (P < 0.05); increased the latency on days 12 and 13 (P < 0.05); and reduced the percentage of time spent in the goal quadrant (P < 0.05) on day 14. Similarly, dexamethasone increased the mNSS on days 7 and 14 (P < 0.05). A strong correlation was observed between these results at 14 days after TBI (r = 0.815-0.892, P < 0.05). These data indicate that DEX inhibits the mobilization of EPC levels and angiogenesis around the lesion after TBI, which may contribute to neuronal cell loss and impaired neurofunction.

Direct implantations of erythropoietin and autologous EPCs in critical limb ischemia (CLI) area restored CLI area blood flow and rescued remote AMI-induced LV dysfunction

BACKGROUND

This study tested the hypothesis that intramuscular injections of erythropoietin (EPO) and endothelial progenitor cells (EPC) to critical limb ischemia (CLI; primary treatment site) could also improve heart function in rat after acute myocardial infarction (AMI; remote ischemic organ).

METHOD

Adult-male SD rats (n = 40) were equally categorized into group 1 (sham-operated control), group 2 (CLI-AMI), group 3 [CLI-AMI + EPO (10 mg/kg)], group 4 [CLI-AMI + EPCs (1.2 × 10⁶)] and group 5 (CLI-AMI + EPCs + EPO).

RESULTS

By day 21 (end of study period), 2-D echo and Laser doppler showed that left-ventricular injection fraction (LVEF) and the ratio of ischemic to normal blood flow were highest in group 1, lowest in group 2, significantly higher in group 5 than in groups 3 and 4, but not different in the latter two groups (all p < 0.0001). Flow cytometry and ELISA demonstrated that circulating angiogenesis factors were significantly progressively increased from groups 1 to 5 (all p < 0.001). The number of small vessels and protein (CD31/eNOS)/cellular (vWF) expressions reflecting integrity of endothelium exhibited an identical pattern to LVEF whereas protein (VEGF/SDF-1α)/cellular (VEGF) expressions were significantly progressively increased from groups 1 to 5 in quadriceps and heart tissues (all p < 0.0001). Protein expressions of apoptotic (Bax/caspase-3/PARP)/inflammatory (MMP-9) and microscopic findings of ischemic/fibrotic/collagen-deposition areas and DNA-damage marker (γ-H2AX+) were lowest in group 1 and significantly progressively decreased from groups 2 to 5 in quadriceps and heart tissues (all p < 0.0001).

CONCLUSIONS

Direct injection of EPO-EPC into CLI effectively restored blood flow in the CLI area and also preserved remote heart function.

Erythropoietin Pretreatment Effect on Blood Glucose and Its Relationship With Inflammatory Factors After Brain Ischemic-Reperfusion Injury in Rats

Introduction:

Brain Ichemic-Reperfusion Injury (IRI) activates different pathophysiological processes. It also changes physiological parameters such as Blood Glucose (BG) level. An increase in BG after stroke is associated with poor clinical outcomes. Erythropoietin has been shown to be effective on both reducing inflammation and BG level. Therefore, in this study the erythropoietin pretreatment effect on BG and its relationship with inflammatory markers after brain IRI was investigated.

Methods:

Thirty adult male Wistar rats were randomly divided into 5 groups: sham, control and 3 pretreatment groups: single dose, double dose, and triple dose that received 1000 U/kg of erythropoietin before stroke induction in different times intraperitoneally. A rat model of IRI was established by Middle Cerebral Artery Occlusion (MCAO) for 60 minutes. Infarct volume, neurological defects, Interleukin-1α (IL-1α) and IL-6 serum levels were evaluated 24 hours after reperfusion. Also BG was measured after 1, 6, and 24 hours.

Results:

Single dose of erythropoietin significantly decreased infarct volume and improved neurological defects which was associated with decreased serum level of IL-1α and IL-6 but higher doses of erythropoietin administration had adverse effects on histological, neurological, and inflammatory results. In addition, erythropoietin significantly increased BG in a dose-dependent manner.

Conclusion:

Erythropoietin could reduce brain IRI by reducing inflammation and BG stabilization. The results of the present study demonstrated a relationship between inflammatory factors and hyperglycemia after IRI and suggested that erythropoietin may be useful for preventing brain IRI, but its higher doses should be used with caution due to possible side effects.

Neurotherapeutic potential of erythropoietin after ischemic injury of the central nervous system

Erythropoietin (EPO) is one of the most successful biopharmaceuticals in history and is used for treating anemia of different origins. However, it became clear that EPO could also work in a neuroprotective, antiapoptotic, antioxidative, angiogenetic and neurotropic way. It causes stimulation of cells to delay cell apoptosis, especially in the central nervous system. In rodent models of focal cerebral ischemia, EPO showed an impressive reduction of infarct size by 30% and improvement of neurobehavioral outcome by nearly 40%. A large animal model dealing with ischemia and reperfusion of the spinal cord showed that EPO could reduce the risk of spinal cord injury significantly. In addition, some clinical studies tested whether EPO works in real live clinical settings. One of the most promising studies showed the innocuousness and improvements in follow-up, outcome scales and in infarct size, of EPO-use in humans suffering from ischemic stroke. Another study ended unfortunately in a negative outcome and an increased overall death rate in the EPO group. The most possible reason was the involvement of patients undergoing simultaneously systemic thrombolysis with recombinant tissue plasminogen activator. An experimental study on rats demonstrated that administration of EPO might exacerbate tissue plasminogen activator-induced brain hemorrhage without reducing the ischemic brain damage. This case shows clearly how useful animal models can be to check negative side effects of a treatment before going into clinical trials. Other groups looked in human trials at the effects of EPO on the outcome after ischemic stroke, relation to circulating endothelial progenitor cells, aneurysmal subarachnoid hemorrhage, traumatic brain injury, hemoglobin transfusion thresholds and elective first-time coronary artery bypass surgery. Most of the results were positive, but are based mostly on small group sizes. However, some of the most neglected facts when focusing on experimental setups of ischemia of the central nervous system are issues like age and comorbidities. It might be extremely worthy to consider these points for future projects, because EPO might influence all these factors.

Intra-carotid arterial transfusion of autologous circulatory derived CD34+ cells for old ischemic stroke patients - a phase I clinical trial to evaluate safety and tolerability

This phase I clinical trial tested the hypothesis that circulatory CD34+ cell therapy might be safe for old ischemic stroke (IS) (defined as IS>6 months) patients and also to evaluate the neurological function after the therapy. Nine old IS patients (with mean IS interval: 8.6 ± 6.4 years) were consecutively enrolled and received intra-carotid artery transfusion of circulatory-derived autologous CD34+ cells (3.0×10⁷ cells/patient) into the ipsilateral brain infarct area at catheterization room by Catheter Looping Technique, after subcutaneous G-CSF injection (5 μg/kg twice a day for 4 days). The results showed that procedural safety was 100% with all patients uneventfully discharged. The circulating number of EPCs and angiogenesis (i.e., by Matrigel assay) were significantly higher at post than at prior to G-CSF treatment (all P<0.001). Time courses (0/5/10/30 minutes) of blood samplings from right-internal jugular vein exhibited significantly increased in levels of SDF-1α and EPCs numbers in time points of 5/10/30 minutes than in the baseline (0 minute) (all P<0.05). Barthel index was increased (defined as ≥5 scores) in 44.4% (4/9) and CASI score was notably improved (all P<0.01) at 6-month follow-up after the cell therapy as compared to the baseline. No recurrent IS or any tumorigenesis was found in these patients with a mean follow-up time interval of 16.5 ± 6.2 months. All of these patients remain survive and are followed up at outpatient department. In conclusion, CD34+ cell therapy is safe and might offer some benefit to old IS patients.

Increased circulating endothelial progenitor cells and improved short-term outcomes in acute non-cardioembolic stroke after hyperbaric oxygen therapy

Background

Acute ischemic stroke is a leading cause of mortality and long-term disability, and profiles of endothelial progenitor cells (EPCs) reflect the degree of endothelial impairment. This study tested the hypothesis that hyperbaric oxygen therapy (HBOT) both improves the clinical short-term outcomes and increases the number of circulating EPCs and antioxidant capacity.

Methods

The numbers of circulating EPCs [CD133⁺/CD34⁺ (%), KDR⁺/CD34⁺ (%)], biomarkers for oxidative stress (thiols and thiobarbituric acid-reactive substances), and clinical scores (National Institutes of Health Stroke Scale [NIHSS], Barthel index [BI], and modified Rankin Scale [MRS]) were prospectively evaluated in 25 patients with acute non-cardioembolic stroke under HBOT at two time points (pre- and post-HBOT). The biomarkers and clinical scores were compared with those of 25 age- and sex-matched disease controls.

Results

The numbers of KDR⁺/CD34⁺ (%) in the HBOT group following HBOT increased significantly, whereas the numbers of CD133⁺/CD34⁺ (%) also showed a tendency to increase without statistical significance. The mean high-sensitivity C-reactive protein levels showed significant decrease post-HBOT follow-up in the HBOT group. The changes in KDR⁺/CD34⁺EPC (%) numbers were positively correlated with changes in clinical outcomes scores (BI, NIHSS, and MRS) in the HBOT group.

Conclusions

Based on the results of our study, HBOT can both improve short-term clinical outcomes and increase the number of circulating EPCs in patients with acute non-cardioembolic stroke.

Histone Deacetylase 7-Derived Peptides Play a Vital Role in Vascular Repair and Regeneration

Cardiovascular disease is a leading cause of morbidity and mortality globally. Accumulating evidence indicates that local resident stem/progenitor cells play an important role in vascular regeneration. Recently, it is demonstrated that a histone deacetylase 7-derived 7-amino acid peptide (7A, MHSPGAD) is critical in modulating the mobilization and orientated differentiation of these stem/progenitor cells. Here, its therapeutic efficacy in vascular repair and regeneration is evaluated. In vitro functional analyses reveal that the 7A peptide, in particular phosphorylated 7A (7Ap, MH[pSer]PGAD), could increase stem cell antigen-1 positive (Sca1+) vascular progenitor cell (VPC) migration and differentiation toward an endothelial cell lineage. Furthermore, local delivery of 7A as well as 7Ap could enhance angiogenesis and ameliorate vascular injury in ischaemic tissues; these findings are confirmed in a femoral artery injury model and a hindlimb ischaemia model, respectively. Importantly, sustained delivery of 7A, especially 7Ap, from tissue-engineered vascular grafts could attract Sca1+-VPC cells into the grafts, contributing to endothelialization and intima/media formation in the vascular graft. These results suggest that this novel type of peptides has great translational potential in vascular regenerative medicine.

Effects of Angiotensin-Converting Enzyme Inhibition on Circulating Endothelial Progenitor Cells in Patients with Acute Ischemic Stroke

Background

Therapeutic neovascularization might represent an important strategy to salvage tissue after ischemia. Circulating bone marrow-derived endothelial progenitor cells (EPCs) were previously shown to augment the neovascularization of ischemic tissue. Angiotensin-converting enzyme inhibitors (ACEIs) might modulate EPC mobilization. We evaluated populations of circulating stem cells and early EPCs in acute ischemic stroke (AIS) patients and the effect of ACEI on circulating EPCs in these patients with respect to aspects of stroke pathogenesis.

Methods

We studied 43 AIS patients (group I), comprising 33 treated with ACEI (group Ia) and 10 untreated (group Ib). Risk factor controls (group II) included 22 subjects. EPCs were measured by flow cytometry.

Results

In AIS patients, the number of circulating stem cells and early EPCs upon admission was similar to that in control group individuals. There were no significant differences in the numbers of stem cells and early EPCs over subsequent days after AIS. There were also no significant differences in stem cell and early EPC numbers over the first 3 days between group Ia and group Ib. However, on day 7, these numbers were significantly higher in group Ib than in group Ia (p < 0.05). In AIS patients chronically treated with ACEI, there was a negative correlation between CD133⁺ cell number and neurological deficit on the first, third, and seventh days (p < 0.005).

Conclusions

An increased number of circulating stem cells and early EPCs were not observed in stroke patients chronically treated with ACEI. In patients chronically treated with ACEI, a significant correlation was observed between decreased neurological deficit and higher levels of CD133⁺ cells; this could be due to the positive influence of these cells on the regeneration of the endothelium and improved circulation in the ischemic penumbra.

Neuroprotective Effects of neuroEPO Using an In Vitro Model of Stroke

Erythropoietin (EPO) is a glycoprotein initially identified as a hormone synthesized and secreted by the kidney that regulates erythropoiesis. EPO, and a group of its derivatives, are being evaluated as possible neuroprotective agents in cerebral ischemia. The objective of this study, using an in vitro model, was to determine how neuroEPO—which is a variant of EPO with a low sialic acid content—protects neurons from the toxic action of glutamate. Primary neuronal cultures were obtained from the forebrains of Wistar rat embryos after 17 days of gestation. Excitotoxicity was induced after nine days of in vitro culture by treatment with a medium containing 100 µM glutamate for 15 min. After this time, a new medium containing 100 ng of neuroEPO/mL was added. Morphological cell change was assessed by phase-contrast microscopy. Oxidative stress was analysed by measuring antioxidant and oxidant activity. After 24 h, the treatment with 100 ng of neuroEPO/mL showed a significant (p < 0.01) decrease in mortality, compared to cells treated with glutamate alone. neuroEPO treatment decreased mortality and tended to reproduce the morphological characteristics of the control. The oxidative stress induced by glutamate is reduced after neuroEPO treatment. These results confirm that neuroEPO has a protective effect against neuronal damage induced by excitotoxicity, improving antioxidant activity in the neuron, and protecting it from oxidative stress.

Treatments to Promote Neural Repair after Stroke

Stroke remains a major cause of human disability worldwide. In parallel with advances in acute stroke interventions, new therapies are under development that target restorative processes. Such therapies have a treatment time window measured in days, weeks, or longer and so have the advantage that they may be accessible by a majority of patients. Several categories of restorative therapy have been studied and are reviewed herein, including drugs, growth factors, monoclonal antibodies, activity-related therapies including telerehabilitation, and a host of devices such as those related to brain stimulation or robotics. Many patients with stroke do not receive acute stroke therapies or receive them and do not derive benefit, often surviving for years thereafter. Therapies based on neural repair hold the promise of providing additional treatment options to a majority of patients with stroke.

Natural compound bavachalcone promotes the differentiation of endothelial progenitor cells and neovascularization through the RORα-erythropoietin-AMPK axis

In cardiovascular diseases, endothelial function is impaired and the level of circulating endothelial progenitor cells (EPCs) is low. This study investigated whether the natural bioactive component bavachalcone (BavaC) induces the differentiation of EPCs and neovascularization in vivo; the underlying mechanisms were also examined. We observed that the treatment of rat bone marrow–derived cells with a very low dose of BavaC significantly promoted EPC differentiation. In our hindlimb ischemia models, low–dose BavaC administered orally for 14 days stimulated the recovery of ischemic hindlimb blood flow, increased circulating EPCs, and promoted capillary angiogenesis. The BavaC treatment of rat bone marrow cells for 24 h initiated the AMP–activated protein kinase (AMPK) activity required for the differentiation of EPCs. Further testing revealed that BavaC and CGP52608, a retinoic acid receptor–related orphan receptor α (RORα) activator, enhanced the activity of RORα1 and EPO luciferase reporter gene. BavaC treatment also elevated EPO mRNA and protein expression in vitro and in vivo and the circulating EPO levels in rats. By contrast, the RORα antagonist VPR66 inhibited BavaC–induced EPO reporter activity, and differentiation of bone marrow cells into endothelial progenitor cells. Overall, this study revealed that BavaC promotes EPC differentiation and neovascularization through a RORα–EPO–AMPK axis. BavaC can be used as a promising angiogenesis agent for enhancing angiogenesis and tissue repair.

Harms of off-label erythropoiesis-stimulating agents for critically ill people

BACKGROUND

Anaemia is a common problem experienced by critically-ill people. Treatment with erythropoiesis-stimulating agents (ESAs) has been used as a pharmacologic strategy when the blunted response of endogenous erythropoietin has been reported in critically-ill people. The use of ESAs becomes more important where adverse clinical outcomes of transfusing blood products is a limitation. However, this indication for ESAs is not licensed by regulatory authorities and is called off-label use. Recent studies concern the harm of ESAs in a critical care setting.

OBJECTIVES

To focus on harms in assessing the effects of erythropoiesis-stimulating agents (ESAs), alone or in combination, compared with placebo, no treatment or a different active treatment regimen when administered off-label to critically-ill people.

SEARCH METHODS

We conducted a systematic search of the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, PsycINFO via OvidSP, CINAHL, all evidence-based medicine (EBM) reviews including IPA and SCI-Expanded, Conference Proceedings Citation Index- Science, BIOSIS Previews and TOXLINE up to February 2017. We also searched trials registries, checked reference lists of relevant studies and tracked their citations by using SciVerse Scopus.

SELECTION CRITERIA

We considered randomized controlled trials (RCTs) and controlled observational studies, which compared scheduled systemic administration of ESAs versus other effective interventions, placebo or no treatment in critically-ill people.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened and evaluated the eligibility of retrieved records, extracted data and assessed the risks of bias and quality of the included studies. We resolved differences in opinion by consensus or by involving a third review author. We assessed the evidence using GRADE and created a 'Summary of findings' table. We used fixed-effect or random-effects models, depending on the heterogeneity between studies. We fitted three-level hierarchical Bayesian models to calculate overall treatment effect estimates.

MAIN RESULTS

Of the 27,865 records identified, 39 clinical trials and 14 observational studies, including a total of 945,240 participants, were eligible for inclusion. Five studies are awaiting classification. Overall, we found 114 adverse events in 33 studies (30 RCTs and three observational studies), and mortality was reported in 41 studies (32 RCTs and nine observational studies). Most studies were at low to moderate risk of bias for harms outcomes. However, overall harm assessment and reporting were of moderate to low quality in the RCTs, and of low quality in the observational studies. We downgraded the GRADE quality of evidence for venous thromboembolism and mortality to very low and low, respectively, because of risk of bias, high inconsistency, imprecision and limitations of study design.It is unclear whether there is an increase in the risk of any adverse events (Bayesian risk ratio (RR) 1.05, 95% confidence interval (CI) 0.93 to 1.21; 3099 participants; 9 studies; low-quality evidence) or venous thromboembolism (Bayesian RR 1.04, 95% CI 0.70 to 1.41; 18,917 participants; 18 studies; very low-quality evidence).There was a decreased risk of mortality with off-label use of ESAs in critically-ill people (Bayesian RR 0.76, 95% CI 0.61 to 0.92; 930,470 participants; 34 studies; low-quality evidence).

AUTHORS' CONCLUSIONS

Low quality of evidence suggests that off-label use of ESAs may reduce mortality in a critical care setting. There was a lack of high-quality evidence about the harm of ESAs in critically-ill people. The information for biosimilar ESAs is less conclusive. Most studies neither evaluated ESAs' harm as a primary outcome nor predefined adverse events. Any further studies of ESA should address the quality of evaluating, recording and reporting of adverse events.

Response of the cerebral vasculature following traumatic brain injury

The critical role of the vasculature and its repair in neurological disease states is beginning to emerge particularly for stroke, dementia, epilepsy, Parkinson's disease, tumors and others. However, little attention has been focused on how the cerebral vasculature responds following traumatic brain injury (TBI). TBI often results in significant injury to the vasculature in the brain with subsequent cerebral hypoperfusion, ischemia, hypoxia, hemorrhage, blood-brain barrier disruption and edema. The sequalae that follow TBI result in neurological dysfunction across a host of physiological and psychological domains. Given the importance of restoring vascular function after injury, emerging research has focused on understanding the vascular response after TBI and the key cellular and molecular components of vascular repair. A more complete understanding of vascular repair mechanisms are needed and could lead to development of new vasculogenic therapies, not only for TBI but potentially vascular-related brain injuries. In this review, we delineate the vascular effects of TBI, its temporal response to injury and putative biomarkers for arterial and venous repair in TBI. We highlight several molecular pathways that may play a significant role in vascular repair after brain injury.

Therapeutic effect of erythropoietin in patients with traumatic brain injury: a meta-analysis of randomized controlled trials

OBJECTIVE

Erythropoietin (EPO) exerts a neuroprotective effect in animal models of traumatic brain injury (TBI). However, its effectiveness in human patients with TBI is unclear. In this study, the authors conducted the first meta-analysis to assess the effectiveness and safety of EPO in patients with TBI.

METHODS

In December 2015, a systematic search was performed of PubMed, Web of Science, MEDLINE, Embase, the Cochrane Library databases, and Google Scholar. Only English-language publications of randomized controlled trials (RCTs) using EPO in patients with TBI were selected for analysis. The assessed outcomes included mortality, favorable neurological outcome, hospital stay, and associated adverse effects. Continuous variables were presented as mean difference (MD) with a 95% confidence interval (CI). Dichotomous variables were presented as risk ratio (RR) or risk difference (RD) with a 95% CI. Statistical heterogeneity was examined using both I2 and chi-square tests.

RESULTS

Of the 346 studies identified in the search, 5 RCTs involving 915 patients met the inclusion criteria. The overall results demonstrated that EPO significantly reduced mortality (RR 0.69, 95% CI 0.49–0.96, p = 0.03) and shortened the hospitalization time (MD −7.59, 95% CI −9.71 to −5.46, p < 0.0001) for patients with TBI. Pooled results of favorable outcome (RR 1.00, 95% CI 0.88–1.15, p = 0.97) and deep vein thrombosis (DVT; RD 0.00, 95% CI −0.05 to 0.05, p = 1.00) did not show a significant difference.

CONCLUSIONS

The authors suggested that EPO is beneficial for patients with TBI in terms of reducing mortality and shortening hospitalization time without increasing the risk of DVT. However, its effect on improving favorable neurological outcomes did not reach statistical significance. Therefore, more well-designed RCTs are necessary to ascertain the optimum dosage and time window of EPO treatment for patients with TBI.

EPO-cyclosporine combination therapy reduced brain infarct area in rat after acute ischemic stroke: role of innate immune-inflammatory response, micro-RNAs and MAPK family signaling pathway

This study tested the hypothesis that erythropoietin (EPO) and cyclosporine (CsA) could effectively reduce brain infarct area (BIA) in rat after acute ischemic stroke (AIS) through regulating inflammation, oxidative stress, MAPK family signaling and microRNA (miR-223/miR-30a/miR-383). Adult male Sprague-Dawley rats (n = 48) were equally divided into group 1 (sham control), group 2 (AIS), group 3 [AIS+EPO (5,000 IU/kg at 0.5/24/48 h, subcutaneous)] and group 4 [AIS+CsA (20.0 mg/kg at 0.5/24/48 h, intra-peritoneal)]. By 72 h, histopathology showed that BIA was largest in group 2 and smallest in group 1, and significantly larger in group 4 than group 3 (all P<0.0001). The three microRNAs expressed were higher in group 2 than in the other three groups (all P<0.04); between these three latter groups there were no significant differences. The protein expressions of MAPK family [phosphorylated (p)-ERK1/2, p-p38/p-JNK], inflammatory (iNOS/MMP-9/TNF-α/NF-κB/IL-12/MIP-1α/CD14/CD68/Ly6g), apoptotic (caspase-3/PARP/mitochondrial-Bax), oxidative-stress (NOX-1/NOX-2/oxidized protein) and mitochondrial-damaged (cytosolic cytochrome-C) biomarkers exhibited an identical pattern to BIA findings (all P<0.0001). The cellular expressions of brain edema (AQP4+), inflammation (CD11+/glial-fibrillary-acid protein+), and cellular damage (TUNEL assay/positive Periodic acid-Schiff stain) biomarkers exhibited an identical pattern, whereas the cellular-integrity markers (neuN+/MAP2+/doublecorin+) exhibited an opposite pattern to BIA (all P value <0.001). EPO-CsA therapy markedly reduced BIA mainly by suppressing the innate immune response to inflammation, oxidative stress, microRNAs (miR-223/miR-30a/miR-383) and MAPK family signaling.

High-sensitivity C-reactive protein in stroke patients - The importance in consideration of influence of multiple factors in the predictability for disease severity and death

High sensitivity C-reactive protein (hsCRP) has been evaluated as a biomarker in stroke and relevant pathological diseases. While its predictive values in several pathological phenotypes have been confirmed, controversy exists among different studies. This review summarizes reports of the predictive values of hsCRP for the diagnosis, etiology, prognosis and mortality of stroke diseases. The current literature suggests that CRP expression is influenced by multiple factors, such as polymorphisms, the genomic backgrounds and gender. However, few reported studies analyzed data based on all these multiple factors. Future studies should focus on comprehensive analysis based on multiple factors.

AG490 suppresses EPO-mediated activation of JAK2-STAT but enhances blood flow recovery in rats with critical limb ischemia

Background

Erythropoietin (EPO) has been demonstrated to enhance recovery in ischemic organs through enhancing angiogenesis. In this study, we used an experimental critical limb ischemia (CLI) rat model to reveal the underlying mechanisms and directly examine the benefits of the anti-apoptotic capacity of EPO in the acute phase of limb ischemia and following blood flow recovery.

Methods

To determine the role of the JAK2/STAT pathway in EPO-enhanced recovery after CLI, male Sprague-Dawley rats (n = 8 for each group) were divided into group 1 (normal control), group 2 (CLI treated with normal saline), group 3 (CLI treated with EPO), group 4 (CLI treated with AG490, a JAK2 inhibitor), and group 5 (CLI treated with EPO and AG490). Animals were sacrificed either at day 1 or day 14 and biochemical and histopathological examination of ischemic quadriceps were conducted.

Results

At day 1, EPO administration reduced expression levels of apoptotic indices and activated the JAK2/STAT pathway; this activation was inhibited by additional AG490 treatment. Furthermore, the decrease in the size of the infarcted area, as well as activation of ERK1/2 and JNK showed similar regulatory trends with EPO or AG490 treatment. Of Interest, EPO and AG490 in combination showed a synergistic effect, increasing expression levels of antioxidants (GR, GPx, NQO-1) and decreasing transcriptional levels of pro-inflammatory factors (TNF-α, NF-kB). At day 14, laser Doppler analysis showed that the blood flow recovery was enhanced by EPO, AG490, or combined treatment.

Conclusion

Although inhibition of the JAK2/STAT pathways reduces the anti-apoptotic effects of EPO in the early phase of CLI, the benefits of AG490 in anti-inflammation and anti-oxidation still play a positive role in enhancing blood flow recovery after CLI.

Endothelial progenitor cells (EPCs) in ageing and age-related diseases: How currently available treatment modalities affect EPC biology, atherosclerosis, and cardiovascular outcomes

Endothelial progenitor cells (EPCs) are mononuclear cells that circulate in the blood and are derived from different tissues, expressing cell surface markers that are similar to mature endothelial cells. The discovery of EPCs has lead to new insights in vascular repair and atherosclerosis and also a new theory for ageing. EPCs from the bone marrow and some other organs aid in vascular repair by migrating to distant vessels where they differentiate into mature endothelial cells and replace old and injured endothelial cells. The ability of EPCs to repair vascular damage depends on their number and functionality. Currently marketed drugs used in a variety of diseases can modulate these characteristics. In this review, the effect of currently available treatment options for cardiovascular and metabolic disorders on EPC biology will be discussed. The various EPC-based therapies that will be discussed include lipid-lowering agents, antihypertensive agents, antidiabetic drugs, phosphodiesteraze inhibitors, hormones, as well as EPC capturing stents.

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.

Extracorporeal shock wave effectively attenuates brain infarct volume and improves neurological function in rat after acute ischemic stroke

BACKGROUND

To investigate the effect of shock wave (SW) on brain-infarction volume (BIV) and neurological function in acute ischemic stroke (AIS) by left internal carotid artery occlusion in rats.

METHODS AND RESULTS

SD rats (n=48) were divided into group 1 [sham-control (SC)], group 2 [SC-ECSW (energy dosage of 0.15 mJ/mm(2)/300 impulses)], group 3 (AIS), and group 4 (AIS-ECSW) and sacrificed by day 28 after IS induction. In normal rats, caspase-3, Bax and TNF-α biomarkers did not differ between animals with and without ECSW therapy, whereas Hsp70 was activated post-ECSW treatment. By day 21 after AIS, Sensorimotor-functional test identified a higher frequency of turning movement to left in group 3 than that in group 4 (P<0.05). By day 28, brain MRI demonstrated lager BIV in group 3 than that in group 4 (P<0.001). Angiogenesis biomarkers at cellular (CD31, α-SMA+) and protein (eNOS) levels and number of neuN+ cells were higher in groups 1 and 2 than those in groups 3 and 4, and higher in group 4 than those in group 3, whereas VEGF and Hsp70 levels were progressively increased from groups 1 and 2 to group 4 (all P<0.001). Protein expressions of apoptosis (Bax, caspase 3, PARP), inflammation (MMP-9, TNF-α), oxidative stress (NOX-1, NOX-2, oxidized protein) and DNA-damage marker (γ-H2AX), and expressions of γ-H2AX+, GFAP+, AQP-4+ cells showed an opposite pattern compared to that of angiogenesis among the four groups (all P<0.001).

CONCLUSION

ECSW therapy was safe and effective in reducing BIV and improved neurological function.

Progress and prospects of endothelial progenitor cell therapy in coronary stent implantation

Drug-eluting stents (DES) have been widely used to treat coronary artery disease (CAD) since their clinical use has significantly reduced the occurrence of in-stent restenosis (ISR) as compared with the initially applied bare-metal stents (BMS). However, analyses of long-term clinical outcome have raised concerns about the serious safety problem of DES, such as ISR caused by late or very late thrombosis. Various studies showed that those complications were associated with vascular endothelial injury/dysfunction or endothelialization delaying. Recently, through biological characterization of endothelial progenitor cells (EPCs), mechanistic understanding of rapid re-endothelialization of the vascular injury sites after coronary stenting has become possible and is a new research hotspot in the prevention of ISR and late/very late stent thrombosis. It has been well recognized that the formation of a functional endothelial layer from EPCs requires a coordinated sequence of multistep and signaling events, which includes cell mobilization, adhesion, migration and finally the differentiation to vascular endothelial cells (VECs). In this review, we summarize and discuss the currently relevant information about EPCs, the mechanism of DES interfering with the natural vascular healing process in preventing or delaying the formation of a functional endothelial layer, and EPCs-mediated acceleration of re-endothelialization at vascular injury sites. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1237-1247, 2016.

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.

Erythropoietin improves long-term neurological outcome in acute ischemic stroke patients: a randomized, prospective, placebo-controlled clinical trial

Introduction

Mortality and disability following ischemic stroke (IS) remains unacceptably high with respect to the conventional therapies. This study tested the effect of erythropoietin (EPO) on long-term neurological outcome in patients after acute IS. This study aimed to evaluate the safety and efficacy of two consecutive doses of EPO (5,000 IU/dose, subcutaneously administered at 48 hours and 72 hours after acute IS) on improving the 90-day combined endpoint of recurrent stroke or death that has been previously reported. A secondary objective was to evaluate the long-term (that is, five years) outcome of patients who received EPO.

Methods

This was a prospective, randomized, placebo-controlled trial that was conducted between October 2008 and March 2010 in a tertiary referral center. IS stroke patients who were eligible for EPO therapy were enrolled into the study.

Results

The results showed that long-term recurrent stroke and mortality did not differ between group 1 (placebo-control; n = 71) and group 2 (EPO-treated; n = 71).

Long-term Barthel index of <35 (defining a severe neurological deficit) was lower in group 2 than group 1 (P = 0.007). Multiple-stepwise logistic-regression analysis showed that EPO therapy was significantly and independently predictive of freedom from a Barthel index of <35 (P = 0.029). Long-term major adverse neurological event (MANE; defined as: death, recurrent stroke, or long-term Barthel index < 35) was lower in group 2 than group 1 (P = 0.04). Log-Rank test showed that MANE-free rate was higher in group 2 than group 1 (P = 0.031). Multiple-stepwise Cox-regression analysis showed that EPO therapy and higher Barthel Index at day 90 were independently predictive of freedom from long-term MANE (all P <0.04).

Conclusion

EPO therapy significantly improved long-term neurological outcomes in patients after IS.

Trial registration

ISRCTN71371114. Registered 10 October 2008.

High-density lipoproteins in stroke

Besides their well-documented function of reverse transport of cholesterol, high-density lipoproteins (HDLs) display pleiotropic effects due to their antioxidant, antithrombotic, anti-inflammatory and antiapoptotic properties that may play a major protective role in acute stroke, in particular by limiting the deleterious effects of ischaemia on the blood-brain barrier (BBB) and on the parenchymal cerebral compartment. HDLs may also modulate leukocyte and platelet activation, which may also represent an important target that would justify the use of HDL-based therapy in acute stroke. In this review, we will present an update of all the recent findings in HDL biology that could support a potential clinical use of HDL therapy in ischaemic stroke.

High-dose erythropoietin for tissue protection

BACKGROUND

The discovery of potential anti-apoptotic and cytoprotective effects of recombinant human erythropoietin (rHuEPO) has led to clinical trials investigating the use of high-dose, short-term rHuEPO therapy for tissue protection in conditions such as stroke and myocardial infarction. Experimental studies have been favourable, but the clinical efficacy has yet to be validated.

MATERIALS AND METHODS

We have reviewed clinical studies regarding the use of high-dose, short-term rHuEPO therapy for tissue protection in humans with the purpose to detail the safety and efficacy of rHuEPO for this indication. A systematic literature search was performed using the PubMed/MEDLINE database for randomized, placebo-controlled clinical trials.

RESULTS

Twenty-six randomized controlled trials that enrolled 3176 patients were included. The majority of trials (20 trials including 2724 patients) reported no effect of rHuEPO therapy on measures of tissue protection. Five trials including 1025 patients reported safety concerns in the form of increased mortality or adverse event rates. No studies reported reduced mortality.

CONCLUSIONS

Evidence is sparse to support a tissue-protective benefit of rHuEPO in humans. Moreover, a number of studies indicate that short-term administration of high-dose rHuEPO is associated with an increased risk of mortality and serious adverse events. Further work is needed to elucidate the mechanisms of toxicity of rHuEPO in humans.

Perinatal arterial ischemic stroke: presentation, risk factors, evaluation, and outcome

BACKGROUND

Perinatal arterial ischemic stroke is as common as large vessel arterial ischemic stroke in adults and leads to significant morbidity. Perinatal arterial ischemic stroke is the most common identifiable cause of cerebral palsy and can lead to cognitive and behavioral difficulties that are amortized over a lifetime.

METHODS

The literature on perinatal arterial ischemic stroke was reviewed and analyzed.

RESULTS

Risk factors for perinatal arterial ischemic stroke include those that are maternal, neonatal, and placental. The most common clinical signs at presentation are seizures and hemiparesis. Evaluation should begin with thorough history acquisition and physical examination followed by magnetic resonance imaging of the brain, with consideration of magnetic resonance angiography of the head and neck, echocardiogram, and thrombophilia evaluation. Treatment beginning early to include physical, speech, and occupational therapies including constraint-induced movement therapy and close cognitive and developmental follow-up may be beneficial. Future treatments may include transcranial magnetic stimulation, hypothermia, and erythropoietin.

CONCLUSIONS

Perinatal arterial ischemic stroke comprises a group of arterial ischemic injuries that can occur in the prenatal, perinatal, and postnatal periods in term and preterm infants with different types of perinatal arterial ischemic stroke having different clinical presentations, risk factors, and long-term outcomes.

Endothelial progenitor cells--potential new avenues to improve neoangiogenesis and reendothelialization

The term endothelial progenitor cell (EPC) was established more than 10 years ago and is used to refer to a group of circulating cells that display endothelial lineage qualities and are able to home to areas of ischemia or vascular injury and to facilitate the repair of damaged blood vessels or develop new vessels as needed. This chapter reviews the current lineage relationships among all the cells called EPC and will clear the terminology used in EPC research. Furthermore, an overview of the clinical and in vitro research, as well as cytokine and drug interactions and potential EPC applications, is given.

Recombinant human erythropoietin improves the neurofunctional recovery of rats following traumatic brain injury via an increase in circulating endothelial progenitor cells

Previous studies show that circulating endothelial progenitor cells (EPCs) promote angiogenesis, which is a process associated with improved recovery in animal models of traumatic brain injury (TBI), and that recombinant human erythropoietin (rhEPO) plays a protective role following stroke. Thus, it was hypothesized that rhEPO would enhance recovery following brain injury in a rat model of TBI via an increase in the mobilization of EPCs and, subsequently, in angiogenesis. Flow cytometry assays using CD34- and CD133-specific antibodies were utilized to identify alterations in EPC levels, CD31 and CD34 antibody-stained brain tissue sections were used to quantify angiogenesis, and the Morris water maze (MWM) test and the modified Neurological Severity Score (mNSS) test were used to evaluate behavioral recovery. Compared with saline treatment, treatment with rhEPO significantly increased the number of circulating EPCs on days 1, 4, 7, and 14 (P < 0.05), improved spatial learning ability on days 24 and 25 (P < 0.05), and enhanced memory recovery on day 26 (P < 0.05). Moreover, rhEPO treatment decreased mNSS assessment scores on days 14, 21, and 25 (P < 0.05). There was a strong correlation between levels of circulating EPCs and CD34- and CD31-positive cells within the injured boundary zone (CD34(+) r = 0.910, P < 0.01; CD31(+) r = 0.894, P < 0.01) and the ipsilateral hippocampus (CD34(+) r = 0.841, P < 0.01; CD31(+) r = 0.835, P < 0.01). The present data demonstrate that rhEPO treatment improved functional outcomes in rats following TBI via an increase in the mobilization of EPCs and in subsequent angiogenesis.