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

The role of calcium-sensing receptor in ginsenoside Rg1 promoting reendothelialization to inhibit intimal hyperplasia after balloon injury

Calcium-sensing receptor (CaSR) is a G protein-coupled receptor, widely distributed in various tissues, including vascular endothelial cells and smooth muscle cells, which plays an important role in the migration and homing of stem/progenitor cells and the proliferation of tissue cells. Restenosis after Percutaneous coronary intervention (PCI) seriously affects its prognosis and application. Our previous research has found that ginsenoside Rg1 (GS-Rg1) can inhibit the occurrence of restenosis after balloon injury of the common carotid artery in rats, but the mechanism is still unclear. In this study, it was found that GS-Rg1 (4, 8, 16 mg/kg) inhibited vascular restenosis caused by balloon injury, and mobilize endothelial progenitor cells (EPCs) to promote reendothelialization and inhibit intimal hyperplasia, which significantly reduced after administration of CaSR antagonist NPS 2143. Interestingly, CaSR and its downstream JNK, P38 were highly expressed in the proliferative intima and participated in the abnormal proliferation of vascular smooth muscle cells mediated by smooth muscle progenitor cells (SMPCs). GS-Rg1 inhibited intimal hyperplasia, while it decreased the expression of CaSR, JNK, and P38. This might relate to the distribution of CaSR and the facilitation of GS-Rg1 on the vascular endothelial repair. It is concluded that CaSR plays a key role in GS-Rg1 promoting reendothelialization to inhibit intimal hyperplasia after balloon Injury.

New Opportunities in Heart Failure with Preserved Ejection Fraction: From Bench to Bedside… and Back

Heart failure with preserved ejection fraction (HFpEF) is a growing public health problem in nearly 50% of patients with heart failure. Therefore, research on new strategies for its diagnosis and management has become imperative in recent years. Few drugs have successfully improved clinical outcomes in this population. Therefore, numerous attempts are being made to find new pharmacological interventions that target the main mechanisms responsible for this disease. In recent years, pathological mechanisms such as cardiac fibrosis and inflammation, alterations in calcium handling, NO pathway disturbance, and neurohumoral or mechanic impairment have been evaluated as new pharmacological targets showing promising results in preliminary studies. This review aims to analyze the new strategies and mechanical devices, along with their initial results in pre-clinical and different phases of ongoing clinical trials for HFpEF patients. Understanding new mechanisms to generate interventions will allow us to create methods to prevent the adverse outcomes of this silent pandemic.

Endothelial Progenitor Cells in Neurovascular Disorders—A Comprehensive Overview of the Current State of Knowledge

Endothelial progenitor cells (EPCs) are a population of cells that circulate in the blood looking for areas of endothelial or vascular injury in order to repair them. Endothelial dysfunction is an important component of disorders with neurovascular involvement. Thus, the subject of involvement of EPCs in such conditions has been gaining increasing scientific interest in recent years. Overall, decreased levels of EPCs are associated with worse disease outcome. Moreover, their functionalities appear to decline with severity of disease. These findings inspired the application of EPCs as therapeutic targets and agents. So far, EPCs appear safe and promising based on the results of pre-clinical studies conducted on their use in the treatment of Alzheimer’s disease and ischemic stroke. In the case of the latter, human clinical trials have recently started to be performed in this subject and provided optimistic results thus far. Whereas in the case of migraine, existing findings pave the way for testing EPCs in in vitro studies. This review aims to thoroughly summarize current knowledge on the role EPCs in four disorders with neurovascular involvement, which are Alzheimer’s disease, cerebral small vessel disease, ischemic stroke and migraine, with a particular focus on the potential practical use of these cells as a treatment remedy.

Unraveling the potential of endothelial progenitor cells as a treatment following ischemic stroke

Ischemic stroke is becoming one of the most common causes of death and disability in developed countries. Since current therapeutic options are quite limited, focused on acute reperfusion therapies that are hampered by a very narrow therapeutic time window, it is essential to discover novel treatments that not only stop the progression of the ischemic cascade during the acute phase, but also improve the recovery of stroke patients during the sub-acute or chronic phase. In this regard, several studies have shown that endothelial progenitor cells (EPCs) can repair damaged vessels as well as generate new ones following cerebrovascular damage. EPCs are circulating cells with characteristics of both endothelial cells and adult stem cells presenting the ability to differentiate into mature endothelial cells and self-renew, respectively. Moreover, EPCs have the advantage of being already present in healthy conditions as circulating cells that participate in the maintenance of the endothelium in a direct and paracrine way. In this scenario, EPCs appear as a promising target to tackle stroke by self-promoting re-endothelization, angiogenesis and vasculogenesis. Based on clinical data showing a better neurological and functional outcome in ischemic stroke patients with higher levels of circulating EPCs, novel and promising therapeutic approaches would be pharmacological treatment promoting EPCs-generation as well as EPCs-based therapies. Here, we will review the latest advances in preclinical as well as clinical research on EPCs application following stroke, not only as a single treatment but also in combination with new therapeutic approaches.

Plasma levels of BDNF and EGF are reduced in acute stroke patients

Stroke affects almost 14 million people worldwide each year. It is the second leading cause of death and a major cause of acquired disability. The degree of initial impairment in cognitive and motor functions greatly affects the recovery, but idiosyncratic factors also contribute. These are largely unidentified, which contributes to making accurate prediction of recovery challenging. Release of soluble regulators of neurotoxicity, neuroprotection and repair are presumably essential. Here we measured plasma levels of known regulators of neuroprotection and repair in patients with mild acute ischemic stroke and compared them to the plasma levels in healthy age and gender matched controls. We found that the levels of BDNF and EGF were substantially lower in stroke patients than in healthy controls, while the levels of bFGF and irisin did not differ between the groups. The lower levels of growth factors highlight that during the acute phase of stroke, there is a mismatch between the need for neuroprotection and repair, and the brain's ability to induce these processes. Large individual differences in growth factor levels were seen among the stroke patients, but whether these can be used as predictors of long-term prognosis remains to be investigated.

Associations between RNA-Binding Motif Protein 3, Fibroblast Growth Factor 21, and Clinical Outcome in Patients with Stroke

Background: RNA-binding motif protein 3 (RBM3) is a cold-induced marker of good functional outcome of ischemic stroke that is promising as a protective target. Fibroblast growth factor 21 (FGF21) is an obesity- and temperature-related hormone that upregulates the expression of RBM3, which is beneficial as a recombinant treatment and has been tested under different experimental pathological conditions, including stroke. However, the interaction between RBM3 and FGF21 has not yet been tested for clinical stroke conditions. Methods: In a sample of 66 stroke patients, we analyzed the associations between the FGF21 and RBM3 serum concentrations on admission and at 72 h, body weight, maximum temperature during the first 24 h, and the outcome of patients at 3 months. We also analyzed their association with biomarkers of obesity (adiponectin and leptin) and inflammation (interleukin-6 (IL-6) and interleukin (IL-10)). Results: Higher concentrations of FGF21 on admission and RBM3 at 72 h were associated with good outcomes. Serum FGF21 and RBM3 were directly related to body mass index and inversely related to the maximum temperature during the first 24 h. We found a positive association between the FGF21 concentrations in obese patients with leptin and a negative correlation with adiponectin in non-obese participants. Conclusions: This clinical study demonstrates the association between RBM3 and FGF21 levels and the outcome of stroke patients. Although further investigations are required, these data support the pharmacological induction of RBM3 as a promising protective therapy.

Associations Between Inflammation, Cardiovascular Regenerative Capacity, and Cardiovascular Events: A Cohort Study

Objective

Circulating progenitor cells possess immune modulatory properties and might mitigate inflammation that is characteristic of patients with coronary artery disease. We hypothesized that patients with fewer circulating progenitor cells (CPCs) will have higher inflammatory markers and worse outcomes.

Approach and Results

Patients with stable coronary artery disease were enrolled in a prospective study enumerating CPCs as CD (cluster of differentiation)-34-expressing mononuclear cells (CD34+) and inflammation as levels of IL (interleukin)-6 and high-sensitivity CRP (C-reactive protein) levels. Patients were followed for 5 years for the end points of death and myocardial infarction with repeat inflammatory biomarkers measured after a median of 2 years. In the entire cohort of 392 patients, IL-6 and high-sensitivity CRP levels remained unchanged (0.3+/-2.4 pg/mL and 0.1+/-1.0 mg/L; P=0.45) after 2 years. CPC counts (log-transformed) were inversely correlated with the change in IL-6 levels (r, -0.17; P<0.001). Using linear regression, IL-6 and high-sensitivity CRP levels declined by -0.59 (95% CI, -0.90 to -0.20) pg/mL and -0.13 (-0.28 to 0.01) mg/L per 1 log higher CPC counts after adjustment for the demographic and clinical variables, as well as medications. Using Cox models adjusted for these risk factors, a rise in 1 pg/mL of IL-6 was associated with a 11% (95% CI, 9-13) greater risk of death/myocardial infarction. We found that the change in IL6 level partly (by 40%) mediated the higher risk of adverse events among those with low CPC counts.

Conclusions

Reduced cardiovascular regenerative capacity is independently associated with progressive inflammation in patients with coronary artery disease that in turn is associated with poor outcomes.

Endothelial GABBR2 Regulates Post-ischemic Angiogenesis by Inhibiting the Glycolysis Pathway

Purpose: Angiogenesis post-ischemia plays an essential role in preventing ischemic damage to tissue by improving the blood recovery. Determining the regulatory mechanism of ischemic angiogenesis, therefore, could provide effective therapeutics for ischemic injury. Materials and Methods: The RNA sequencing (RNA-seq) database was used to predict the association of gamma-aminobutyric acid type B receptor subunit 2 (GABBR2) with endothelial-specific expression. The role of GABBR2 in angiogenesis was verified in vitro by downregulating GABBR2 in human umbilical vein endothelial cells (HUVECs) with lentiviral vectors. Besides, the in vivo effect of GABBR2 on the blood recovery of an ischemic hindlimb was demonstrated by establishing a hindlimb ischemia model in normal and GABBR2 adenoviral vector-infected mice. Then, the mobilization of endothelial progenitor cells (EPCs) in peripheral blood post-ischemia was determined by flow cytometry. Finally, the XF analyzer and Western blot were used to determine the effect of GABBR2 on endothelial metabolism. Results: The RNA-seq results indicated a strong association between GABBR2 and endothelial revascularization, and the upregulation of GABBR2 was detected in both hypoxia-treated HUVECs and ischemic mouse hindlimb. Hypoxia treatment for 6 h increased the proliferation, migration, and tube formation of HUVECs, which were inhibited by GABBR2 knockdown. Additionally, GABBR2 downregulation significantly decreased the blood flow recovery of mouse ischemic hindlimb. The expressions of the EPC markers CD34⁺ and CD133⁺ significantly decreased in the peripheral blood in hindlimb post-ischemia. Mechanically, glycolysis-dominated metabolism of HUVECs was compromised by GABBR2 knockdown. Evidences of the decreased expressions of HKII, PFKFB3, and PKM1 also supported the compromised glycolysis induced by GABBR2 downregulation. Conclusion: Our study demonstrated that GABBR2 regulated angiogenesis post-ischemia by inhibiting the glycolysis pathway.

Roles of Fibroblast Growth Factors and Their Therapeutic Potential in Treatment of Ischemic Stroke

Stroke is the leading cause of death worldwide, and its treatment remains a challenge. Complex pathological processes are involved in stroke, which causes a reduction in the supply of oxygen and energy to the brain that triggers subsequent cascade events, such as oxidative stress, inflammatory responses and apoptosis, resulting in brain injury. Stroke is a devastating disease for which there are few treatments, but physical rehabilitation can help improve stroke recovery. Although there are very few treatments for stroke patients, the discovery of fibroblast growth factors (FGFs) in mammals has led to the finding that FGFs can effectively treat stroke in animal models. As presented in this review, FGFs play essential roles by functioning as homeostatic factors and controlling cells and hormones involved in metabolism. They could be used as effective therapeutic agents for stroke. In this review, we will discuss the pharmacological actions of FGFs on multiple targets, including their ability to directly promote neuron survival, enhance angiogenesis, protect against blood-brain barrier (BBB) disruption, and regulate microglial modulation, in the treatment of ischemic stroke and their theoretical mechanisms and actions, as well as the therapeutic potential and limitations of FGFs for the clinical treatment of stroke.

Persistent inflammation worsens short-term outcomes in massive stroke patients

Background

Persistent inflammation is an important driver of disease progression and affects prognosis. Some indicators of inflammation predict short-term outcomes. The relationship between prognosis, especially mortality, and persistent inflammation in massive stroke has not been studied, and this has been the subject of our research.

Methods

From April 1, 2017 to February 1, 2020, consecutive patients were prospectively enrolled. Clinical data, laboratory data, imaging data and follow-up infections morbidity were compared between 2 groups according to modified Rankin scale (mRS) scores (mRS < 3 and ≥ 3) at 1 month. The binomial logistic analysis was used to determine independent factors of 1-month prognosis. Short-term functional outcome, mortality and infection rates in massive stroke with and without persistent inflammation were compared.

Results

One hundred thirty-nine patients with massive stroke were included from 800 patients. We found that admission blood glucose levels (p = 0.005), proportions of cerebral hemispheric (p = 0.001), posterior circulatory (p = 0.035), and lacunar (p = 0.022) ischemia were higher in poor outcome patients; neutrophil-to-lymphocyte ratio (odd ratio = 1.87, 95%CI 1.14–3.07, p = 0.013) and blood glucose concentrations (odd ratio = 1.34, 95%CI 1.01–1.79, p = 0.043) can independently predict the short-term prognosis in massive stroke patients. We also found that the incidence of pulmonary infection (p = 0.009), one-month mortality (p = 0.003) and adverse outcomes (p = 0.0005) were higher in patients with persistent inflammation.

Conclusions

This study suggested that persistent inflammation is associated with poor prognosis, 1-month mortality and the occurrence of in-hospital pulmonary infection and that higher baseline inflammation level predicts short-term poor outcomes in massive stroke.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-021-02097-9.

The effect of endothelial progenitor cell transplantation on neointimal hyperplasia and reendothelialisation after balloon catheter injury in rat carotid arteries

Background

Reendothelialisation is the natural pathway that inhibits neointimal hyperplasia and in-stent restenosis. Circulating endothelial progenitor cells (EPCs) derived from bone marrow (BM) might contribute to endothelial repair. However, the temporal and spatial distributions of reendothelialisation and neointimal hyperplasia after EPC transplantation in injured arteries are currently unclear.

Methods

A carotid balloon injury (BI) model was established in Sprague-Dawley rats, and PKH26-labelled BM-derived EPCs were transplanted after BI. The carotid arteries were harvested on the first, fourth, seventh, and 14th day post-injury and analysed via light-sheet fluorescence microscopy and pathological staining (n = 3). EPC and human umbilical vein endothelial cell culture supernatants were collected, and blood samples were collected before and after transplantation. The paracrine effects of VEGF, IGF-1, and TGF-β1 in cell culture supernatants and serum were analysed by enzyme-linked immunosorbent assay (n = 4).

Results

Transplanted EPCs labelled with PKH26 were attached to the injured luminal surface the first day after BI. In the sham operation group, the transplanted EPCs did not adhere to the luminal surface. From the fourth day after BI, the mean fluorescence intensity of PKH26 decreased significantly. However, reendothelialisation and inhibition of neointimal hyperplasia were significantly promoted by transplanted EPCs. The degree of reendothelialisation of the EPC^7d and EPC^14d groups was higher than that of the BI^7d and BI^14d groups, and the difference in neointimal hyperplasia was observed between the EPC^14d and BI^14d groups. The number of endothelial cells on the luminal surface of the EPC^14d group was higher than that of the BI^14d group. The number of infiltrated macrophages in the injured artery decreased in the EPC transplanted groups.

Conclusions

Transplanted EPCs had chemotactic enrichment and attached to the injured arterial luminal surface. Although decreasing significantly after the fourth day at the site of injury after transplantation, transplanted EPCs could still promote reendothelialisation and inhibit neointimal hyperplasia. The underlying mechanism is through paracrine cytokines and not differentiation into mature endothelial cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02135-w.

Premobilization of CD133+ progenitors is associated with attenuated inflammation-induced pulmonary dysfunction following extracorporeal circulation in mice

OBJECTIVES

Progenitor cells mobilized by granulocyte colony-stimulating factor (G-CSF) have been shown to lessen acute kidney injury induced by extracorporeal circulation (ECC). Both acute kidney injury and lung injury are characterized by endothelial dysfunction. Our goal was to examine whether and how G-CSF-mobilized progenitors with endothelial capacity may help mitigate ECC-induced pulmonary dysfunction.

METHODS

G-CSF (10 μg/kg/day) was administered subcutaneously to C57BL/6 mice before or at the initiation of the ECC process, after which lung injury was assessed by measuring neutrophils in the fluid from bronchoalveolar lavage and determining the pathological score in lung tissue. CD133+ progenitors were isolated and injected into C57BL/6 mice before ECC in vivo. We incubated the CD133+ cells with pulmonary monocytes or neutrophils isolated from naïve mice in vitro.

RESULTS

Pretreatment with G-CSF for 2 days significantly decreased the number of neutrophils in the bronchoalveolar lavage fluid, and the pathological score (P < 0.01; n = 5) improved the PaO2/FiO2 ratio [193.4 ± 12.7 (ECC without G-CSF) vs 305.6 ± 22.6 mmHg (ECC with G-CSF); P = 0.03, n = 5] and suppressed neutrophil elastase and tumour necrosis factor-α levels in the circulation; we also observed increases in both circulating and pulmonary populations of CD133+ progenitors. Similar effects were observed in animals pretreated with CD133+ progenitors instead of G-CSF before ECC. The majority of CD133+/CD45- and CD133+/CD45+ progenitors were mobilized in the lung and in the circulation, respectively. Incubating CD133+ progenitors with neutrophils or pulmonary monocytes blocked lipopolysaccharide-induced release of inflammatory factors.

CONCLUSIONS

Our results suggest that pretreatment of G-CSF attenuates ECC-induced pulmonary dysfunction through inhibiting the inflammatory response in lung tissue and in the circulation with associated premobilization of CD133+ progenitors.

Markers of Endothelial Cells in Normal and Pathological Conditions

Endothelial cells (ECs) line the blood vessels and lymphatic vessels, as well as heart chambers, forming the border between the tissues, on the one hand, and blood or lymph, on the other. Such a strategic position of the endothelium determines its most important functional role in the regulation of vascular tone, hemostasis, and inflammatory processes. The damaged endothelium can be both a cause and a consequence of many diseases. The state of the endothelium is indicated by the phenotype of these cells, represented mainly by (trans)membrane markers (surface antigens). This review defines endothelial markers, provides a list of them, and considers the mechanisms of their expression and the role of the endothelium in certain pathological conditions.

Ginsenoside Rg1 prevents vascular intimal hyperplasia involved by SDF-1α/CXCR4, SCF/c-kit and FKN/CX3CR1 axes in a rat balloon injury

ETHNOPHARMACOLOGICAL RELEVANCE

Panax ginseng C. A. Mey. is a traditional tonic that has been used for thousands of years, and has positive effects on vascular diseases. Ginsenoside Rg1 (GS-Rg1) is one of the active ingredients of Panax ginseng C. A. Mey. and has been shown to have beneficial effects against ischemia/reperfusion injury. Our previously study has found that GS-Rg1 can mobilize bone marrow stem cells and inhibit vascular smooth muscle proliferation and phenotype transformation. However, pharmacological effects and mechanism of GS-Rg1 in inhibiting intimal hyperplasia is still unknown.

AIM OF THE STUDY

This study was aimed to investigate whether GS-Rg1 prevented vascular intimal hyperplasia, and the involvement of stromal cell-derived factor-1α (SDF-1α)/CXCR4, stem cell factor (SCF)/c-kit and fractalkine (FKN)/CX3CR1 axes.

MATERIALS AND METHODS

Rats were operated with carotid artery balloon injury. The treatment groups were injected with 4, 8 and 16 mg/kg of GS-Rg1 for 14 days. The degree of intimal hyperplasia was evaluated by histopathological examination. The expression of α-SMA (α-smooth muscle actin) and CD133 were detected by double-label immunofluorescence. Serum levels of SDF-1α, SCF and soluble FKN (sFKN) were detected by enzyme linked immunosorbent assay (ELISA). The protein expressions of SCF, SDF-1α and FKN, as well as the receptors c-kit, CXC chemokine receptor type 4 (CXCR4) and CX3C chemokine receptor type 1 (CX3CR1) were detected by immunochemistry.

RESULTS

GS-Rg1 reduced intimal hyperplasia by evidence of the values of NIA, the ratio of NIA/MA, and the ratio of NIA/IELA and the ratio of NIA/LA, especially in 16 mg/kg group. Furthermore, GS-Rg1 8 mg/kg group and 16 mg/kg group decreased the protein expressions of the SDF-1α/CXCR4, SCF/c-kit and FKN/CX3CR1 axes in neointima, meanwhile GS-Rg1 8 mg/kg group and 16 mg/kg group also attenuated the expressions of SDF-1α, SCF and sFKN in serum. In addition, the expression of α-SMA and CD133 marked smooth muscle progenitor cells (SMPCs) was decreased after GS-Rg1 treatment.

CONCLUSIONS

GS-Rg1 has a positive effect on inhibiting vascular intimal hyperplasia, and the underlying mechanism is related to inhibitory expression of SDF-1α/CXCR4, SCF/c-kit and FKN/CX3CR1 axes.

Upregulation of MicroRNA-125b Leads to the Resistance to Inflammatory Injury in Endothelial Progenitor Cells

Objectives

MicroRNA-125b (miR-125b) has been recognized as one of the key regulators of the inflammatory responses in cardiovascular diseases recently. This study sought to dissect the role of miR-125b in modulating the function of endothelial progenitor cells (EPCs) in the inflammatory environment of ischemic hearts.

Methods

EPCs were cultured and transfected with miR-125b mimic and negative control mimic. Cell migration and adhesion assays were performed after tumor necrosis factor-α (TNF-α) treatment to determine EPC function. Cell apoptosis was analyzed by flow cytometry. The activation of the NF-κB pathway was measured by western blotting. EPC-mediated neovascularization in vivo was studied by using a myocardial infarction model.

Results

miR-125b-overexpressed EPCs displayed improved cell migration, adhesion abilities, and reduced cell apoptosis compared with those of the NC group after TNF-α treatment. miR-125b overexpression in EPCs ameliorated TNF-α-induced activation of the NF-κB pathway. Mice transplanted with miR-125b-overexpressed EPCs showed improved cardiac function recovery and capillary vessel density than the ones transplanted with NC EPCs.

Conclusions

miR-125b protects EPCs against TNF-α-induced inflammation and cell apoptosis by attenuating the activation of NF-κB pathway and consequently improves the cardiac function recovery and EPC-mediated neovascularization in the ischemic hearts.

Stem and Progenitor Cells in the Pathogenesis and Treatment of Digestive Diseases

The global epidemic of chronic degenerative diseases expands rapidly. The pathogenesis of these noncommunicable disorders revolves around innate immunity, microbiome, and stem cell alterations. Understanding the mechanisms behind stem cell biology and their regulatory pathways is a key to understanding the origin of human disease. Stem cells are involved in tissue and organ damage and regeneration. The evidence is mounting that not only eukaryotic cells but also gut microbiota may release extracellular microvesicles that are absorbed from the gut into the portal and systemic circulation. Linking the fields of stem cells, innate immunity and microbiome research opens up new avenues to develop novel diagnostic (e.g., biomarkers), therapeutic (e.g., microbiome modulation, stem cell-based medicines), and prognostic (personalized diets) tools. In this chapter, we present the short overview of various stem and progenitor cells of adult tissues circulating in peripheral blood and their role in the pathogenesis and treatment of digestive diseases. We also briefly discuss the role of host-stem cell-microbial interactions as a new frontier of research in gastroenterology.

Harnessing the anti-inflammatory properties of stem cells for transplant therapy in hemorrhagic stroke

Hemorrhagic stroke is a global health crisis plagued by neuroinflammation in the acute and chronic phases. Neuroinflammation approximates secondary cell death, which in turn robustly contributes to stroke pathology. Both the physiological and behavioral symptoms of stroke correlate with various inflammatory responses in animal and human studies. That slowing the secondary cell death mediated by this inflammation may attenuate stroke pathology presents a novel treatment strategy. To this end, experimental therapies employing stem cell transplants support their potential for neuroprotection and neuroregeneration after hemorrhagic stroke. In this review, we evaluate experiments using different types of stem cell transplants as treatments for stroke-induced neuroinflammation. We also update this emerging area by examining recent preclinical and clinical trials that have deployed these therapies. While further investigations are warranted to solidify their therapeutic profile, the reviewed studies largely posit stem cells as safe and potent biologics for stroke, specifically owing to their mode of action for sequestering neuroinflammation and promoting neuroregenerative processes.

Differentiation potential and functional properties of a CD34‑CD133+ subpopulation of endothelial progenitor cells

Endothelial progenitor cells (EPCs) promote angiogenesis and play an important role in myocardial and vascular repair after ischemia and infarction. EPCs consist of different subpopulations including CD34‑CD133+ EPCs, which are precursors of more mature CD34+CD133+ EPCs and functionally more active in terms of homing and endothelial regeneration. In the present study we analyzed the functional and differentiation abilities of CD34‑CD133+ EPCs. Isolation of EPC populations (CD34+CD133+, CD34‑CD133+) were performed by specific multi‑step magnetic depletion. After specific stimulation a significant higher adhesive and migrative capacity of CD34‑CD133+ cells could be detected compared to CD34+CD133+ cells (P<0.001, respectively). Next to this finding, not only significantly higher rates of proliferation (P<0.005) were detected among CD34‑CD133+ cells, but also a higher potential of cell‑differentiation capacity into other cell types. Next to a significant increase of CD34‑CD133+ EPCs differentiating into a fibroblast cell‑type (P<0.001), an enhancement into a hepatocytic cell‑type (P=0.033) and a neural cell‑type (P=0.016) could be measured in contrast to CD34+CD133+ cells. On the other hand, there was no significant difference in differentiation into a cardiomyocyte cell‑type between these EPC subpopulations (P=0.053). These results demonstrate that EPC subpopulations vary in their functional abilities and, to different degrees, have the capacity to transdifferentiate into unrelated cell‑types such as fibroblasts, hepatocytes, and neurocytes. This indicates that CD34‑CD133+ cells are more pluripotent compared to the CD34+CD133+ EPC subset, which may have important consequences for the therapy of vascular diseases.

Biomarkers for vascular ageing in aorta tissues and blood samples

OBJECTIVES

Functional and quantitative alterations and senescence of circulating and expanded endothelial progenitor cells (EPC), as well as systemic and tissue modifications of angiogenetic and inflammatory molecules, were evaluated for predicting age-related vessel wall remodeling, correlating them to intima media thickness (IMT) in the common carotid artery (CCA), a biomarker of early cardiovascular disease and aortic root dilation.

POPULATIONS AND METHODS

A homogenous Caucasian population was included in the study, constituted by 160 healthy subjects (80 old subjects, mean age 72 ± 6.4, range 66-83 years; and 80 younger blood donors, mean age 26.2 ± 3.4, range 21-33 years), and 60 old subjects (mean age 73 ± 1.4 (range 66-83) years) with aortic root dilatation and hypertension, and 60 old people (70 ± 2.8 (age range 66-83)) with sporadic ascending aorta aneurysm (AAA). In addition, 20 control individuals (10 men and 10 women, mean age: 65 ± 8), were also included in the study for evaluating the gene expression's levels, in aorta tissues. Appropriate techniques, practises, protocols, gating strategies and statistical analyses were performed in our evaluations.

RESULTS

Interestingly, old people had a significantly reduced functionality and a high grade of senescence (high SA-β-Gal activity and high levels of TP53, p21 and p16 genes) of EPC expanded than younger subjects. The values of related parameters progressively augmented from the old subjects, in good healthy shape, to subjects with hypertension and aorta dilation, and AAA. Moreover, they significantly impacted the endothelium than the alterations in EPC number. No changes, but rather increased systemic levels of VEGF and SDF-1 were also assessed in old people vs. younger donors. Old people also showed significantly increased systemic levels of inflammatory cytokines, and a reciprocal significant reduction of systemic s-Notch 1 than younger subjects. These parameters, also including the number EPC alterations, resulted to be significantly sustained in old people bearers of an inflammatory combined genotype. Consistent with these data, a reduced expression of Notch-1 gene, accompanied by a sustained expression of inflammatory genes (i.e. TLR4, IL-1β, IL-6 and IL-17) were detected in aortic tissues from old control people and AAA cases. Finally, we detected the biological effects induced by all the detected alterations on vessel wall age-related remodeling, by evaluating the IMT in the population studied and correlating it to these alterations. The analysis demonstrated that the unique independent risk predictors for vascular ageing are age, the EPC reduced migratory activity and senescence, high grade of expression of genes inducing EPC senescence and chronic tissue and systemic inflammation.

CONCLUSIONS

Thus, we propose these parameters, of easy determination in biological samples (i.e. blood and tissue samples) from alive human population, as optimal biomarkers for vascular ageing.