Improve Endothelial Progenitor Cells Function Research Articles

The Mechanism of miR-21-5p/TSP-1-Mediating Exercise on the Function of Endothelial Progenitor Cells in Aged Rats.

(1) Background: The declined function of peripheral circulating endothelial progenitor cells (EPCs) in aging individuals resulted in decreased endothelial cell regeneration and vascular endothelial function. Improving EPCs function in aging individuals plays an important role in preventing cardiovascular diseases. (2) Methods: Thirty aged (18-month-old) male Sprague-Dawley rats were randomly divided into control and exercise groups. An aerobic exercise intervention was performed 5 days/week for 8 weeks. EPCs functions, miR-21-5p, and TSP-1 expressions were detected after the intervention. The senescence rate, proliferation, and migration of EPCs were examined after overexpression of miR-21-5p and inhibition of TSP-1 expression. (3) Results: The senescence rate, proliferation, and migration of EPCs in exercise groups were significantly improved after exercise intervention. The miR-21-5p expression was increased and the TSP-1 mRNA expression was decreased in the EPCs after the intervention. miR-21-5p overexpression can improve EPCs function and inhibit TSP-1 expression but has no effect on senescence rate. Inhibition of TSP-1 expression could improve the function and reduce the senescence rate. (4) Conclusions: Our results indicate that long-term aerobic exercise can improve the functions of EPCs in aging individuals by downregulating TSP-1 expression via miR-21-5p, which reveals the mechanism of exercise in improving cardiovascular function.

CXCR7 Agonist TC14012 Improves Angiogenic Function of Endothelial Progenitor Cells via Activating Akt/eNOS Pathway and Promotes Ischemic Angiogenesis in Diabetic Limb Ischemia.

Endothelial progenitor cells (EPCs) play a critical role in repairing damaged vessels and triggering ischemic angiogenesis, but their number is reduced and function is impaired under diabetic conditions. Improving EPC function has been considered a promising strategy to ameliorate diabetic vascular complications. In the present study, we aim to investigate whether and how CXCR7 agonist TC14012 promotes the angiogenic function of diabetic EPCs. High glucose (HG) treatment was used to mimic the hyperglycemia in diabetes. Tube formation, cell scratch recovery and transwell assay, terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, and cleaved-caspase3 expression were used to evaluate the angiogenic capability, cell migration, and apoptosis of EPCs, respectively. Hind limb ischemia (HLI) model was used to appraise the ability of TC14012 in promoting diabetic ischemic angiogenesis in vivo. HG treatment impaired EPC tube formation and migration, and induced EPC apoptosis and oxidative damage, while TC14012 rescued tube formation and migration, and prevented HG-induced apoptosis and oxidative damage of EPCs. Furthermore, these beneficial effects of TC14012 on EPCs were attenuated by specific siRNAs against CXCR7, validating that CXCR7 is a functional target of TC14012 in EPCs. Mechanistic studies demonstrated that HG treatment reduced CXCR7 expression in EPCs, and impaired Akt and endothelial nitric oxide synthase (eNOS) phosphorylation and nitric oxide (NO) production; similarly, these signal impairments in HG-exposed EPCs could be rescued by TC14012. However, the protective effects of TC14012 on tube formation and migration, Akt and eNOS phosphorylation, and NO production in HG-treated EPCs were almost completely abolished by siRNAs against CXCR7 or Akt specific inhibitor wortmannin. More importantly, in vivo study showed that TC14012 administration enhanced blood perfusion recovery and angiogenesis in the ischemic hind limb and increased the EPC number in peripheral circulation of db/db mice, demonstrating the capability of TC14012 in promoting EPC mobilization and ischemia angiogenic function. TC14012 can prevent EPCs from HG-induced dysfunction and apoptosis, improve eNOS activity and NO production via CXCR7/Akt signal pathway, and promote EPC mobilization and diabetic ischemia angiogenesis.

Low-Dose Piperlongumine Rescues Impaired Function of Endothelial Progenitor Cells and Reduces Cerebral Ischemic Injury in High-Fat Diet-Fed Mice.

It is of great clinical significance to develop potential novel strategies to prevent cardio-cerebrovascular complications in patients with hyperlipidemia. Vascular Endothelial integrity and function play a key role in the prevention of cardio-cerebrovascular diseases. Endothelial progenitor cells (EPCs) can home to sites of ischemic injury and promote endothelial regeneration and neovascularization. Hypercholesterolemia impairs the function of EPC. The present study attempted to identify the effect of piperlongumine on EPCs’ angiogenic potential and cerebral ischemic injury in high-fat diet-fed (HFD-fed) mice. Here, we showed that treatment with low-does piperlongumine (0.25 mg/kg/day) for 8 weeks significantly improved EPCs function and reduced the cerebral ischemic injury (both infarct volumes and neurobehavioral outcomes) in HFD-fed mice. In addition, low-dose piperlongumine administration increased intracellular NO level and reduced intracellular O2 - level in EPCs of HFD-fed mice. Moreover, incubation with piperlongumine (1.0 μM, 24 h) reduced thrombospondin-1/2 (TSP-1/2, a potent angiogenesis inhibitor) expression levels in EPCs from HFD-fed mice, increased the therapeutic effect of EPC from HFD-fed mice on cerebral ischemic injury reduction and angiogenesis promotion in HFD-fed mice, and the donor derived EPCs homed to the recipient ischemic brain. In conclusion, low-dose piperlongumine can enhance EPCs’ angiogenic potential and protect against cerebral ischemic injury in HFD-fed mice. It is implied that treatment with low-dose piperlongumine might be a potential option to prevent ischemic diseases (including stroke) in patients with hyperlipidemia, and priming with piperlongumine might be a feasible way to improve the efficacy of EPC-based therapy for ischemic diseases.

Effects of antihyperglycemics on endothelial progenitor cells

Endothelial progenitor cells (EPCs) play an important role in diabetic vascular complications. A large number of studies have revealed that some clinical antihyperglycemics can improve the complications of diabetes by regulating the function of EPCs. Metformin can improve EPCs function in diabetic patients by regulating oxidative stress level or downstream signaling pathway of adenosine monophosphate activated protein kinase; Pioglitazone can delay the aging of EPCs by regulating telomerase activity; acarbose, sitagliptin and insulin can promote the proliferation, migration and adhesion of EPCs. In addition to lowering blood glucose, the effects of antihyperglycemics on EPCs may also be one of the mechanisms to improve the complications of diabetes. This article reviews the research progress on the regulation of EPC proliferation and function by antihyperglycemics.

Metoprolol rescues endothelial progenitor cell dysfunction in diabetes.

Added risk portended by diabetes in addition to hypertension has been related to an amplification of endothelial dysfunction. β-blockers are widely used for cardiovascular diseases and improve the endothelial function compared with a placebo. However, the effect of β-blockers on the endothelial progenitor cells (EPCs) function in diabetes is still unknown. Five β-blockers (metoprolol, atenolol, propranolol, bisoprolol, and nebivolol) were tested in EPC functional screening. Metoprolol improved EPC function significantly among the five β-blockers and was chosen for the in vivo tests in STZ induced diabetic mice. Reactive hyperemia peripheral arterial tonometry (RH-PAT) measurements were performed using the Endo-PAT2000 device in diabetic patients. Metoprolol, but not other β-blockers, improved EPC function in both tube formation and migration assay. EPC function was significantly decreased in diabetic mice, and metoprolol treatment restored damaged EPC migration capabilities and circulation EPC number. Metoprolol treatment promoted wound healing and stimulated angiogenesis in diabetic mice. Furthermore, metoprolol significantly enhanced eNOS phosphorylation and decreased O2− levels in EPCs of diabetic mice. In clinical trials, the RH-PAT index was significantly higher in metoprolol-treated versus bisoprolol-treated diabetics. Metoprolol could accelerate wound healing in diabetic mice and improve endothelial function in diabetic subjects, which may be mediated in part by improving impaired EPC function.

Aerobic and resistance training enhances endothelial progenitor cell function via upregulation of caveolin-1 in mice with type 2 diabetes

BackgroundTo explore the effect of aerobic training (AT), resistance training (RT) or a combination of AT and RT (AT+RT) on the function of endothelial progenitor cells (EPCs) in mice with type 2 diabetes and the potential effective mechanismsMethodsEight-week-old db/db male mice were used as type 2 diabetic animal models in this study. Mice were randomly assigned to the control group (n = 5), AT group (n = 5), RT group (n = 5) and AT+RT group (n = 5). Mice in the control group remained sedentary with no specific training requirement. Mice were motivated to perform AT, RT or AT+RT by a gentle pat on their body for 3 or 4 days/week for 14 days. AT was performed by treadmill running, RT was performed by ladder climbing and AT+RT involved both AT and RT. Bone-derived EPCs were isolated after 14 days of the intervention. EPC expression of CD31, CD34, CD133, CD144 and VEGFR2 was detected by immunofluorescence staining. Fluorescence detection was performed on attached mononuclear cells to detect double-positive EPCs. We then explored the effect of caveolin-1 knockdown (lentiviral vector with caveolin-1-siRNA) on the proliferation and adherence of EPCs and the concentration of caveolin-1 and PI3K/AKT via western blot analyses.ResultsCompared to the mice in the control group, the mice in the AT, RT and AT+RT groups presented significant increases in proliferation and adherence after 14 days of intervention. AT+RT induced an increase in EPC adherence, which was greater than that of the control, RT and AT groups. Caveolin-1 knockdown inhibited the EPC proliferative and adherent abilities. The AT+RT group showed higher levels of caveolin-1 and p-AKT than the control group, but these changes were decreased by caveolin-1-siRNA transfection.ConclusionCombined AT and RT is an effective way to improve EPC function through upregulation of caveolin-1 in mice with type 2 diabetes.

Metformin Inhibits the Expression of Biomarkers of Fibrosis of EPCs In Vitro.

Endothelial progenitor cells (EPCs) are a group of circulating cells with important functions in vascular repair and treatment of cardiovascular diseases. However, in patients with atrial fibrillation (AF), the number and function of EPCs reportedly are decreased. TGF-β is highly expressed in AF patients. In this study, we examined the effect of TGF-β1 on EPCs and the therapeutic outcome of metformin treatment on TGF-β1-induced EPCs. EPCs were induced with TGF-β1 at different concentrations (5 ng/ml, 10 ng/ml, and 20 ng/ml) for 48 h followed by western blot, qPCR, and immunofluorescence analyses to investigate changes in the levels of the fibrosis-related proteins, α-SMA, Col I, Col III, CTGF, and MMP-1. Live-dead cell staining was used to evaluate cell apoptosis. Compared with the control, TGF-β1 treatment significantly (p < 0.05) enhanced the levels of α-SMA, Col I, Col III, CTGF, and MMP-1 in a dose-dependent manner. The most effective concentration of TGF-β1 (20 ng/ml) was then used to induce fibrosis biomarker expression in EPCs, followed by treatment with metformin at different concentrations (0.5, 1, and 2 mmol/l). Metformin treatment suppressed TGF-β-induced expression of all above factors, with the effect at 2 mmol/l being significant (p < 0.05). Live-dead cell staining showed no difference among the control, TGF-β1-treated, and metformin-treated groups. In conclusion, our study showed that TGF-β1 induces the expression of fibrosis biomarkers in EPCs, which is attenuated by treatment with metformin. Thus, metformin may have therapeutic potential for improving EPC function in cardiovascular diseases.

Abstract 336: MiR-126 Modified Endothelial Progenitor Cells Transplantation Contributes to Angiogenesis after Brain Focal Ischemia in SHR Rats

Background and Purpose: Transplantation of endothelial progenitor cells (EPCs) leads to better outcomes in experimental stroke, while improve the EPCs survival rate in ischemia area is still a challenge. MiR-126 modulates vascular development and angiogenesis. Here we overexpressed miR-126 in transplanted EPCs, to investigate the function of gene modified EPCs in angiogenesis after brain ischemia. Methods: Adult male SHR rats underwent permanent suture middle cerebral artery occlusion (MCAO). One week after middle cerebral artery occlusion, the animals received tail vein injection of miR-126 modified EPCs as treatment or EPCs as control and were monitored for 5 weeks. Brain water content, infarct volume, neurological score, neurogenesis and angiogenesis were examined. Results: Neurological score was greatly improved and brain atrophy was greatly reduced in miR-126 modified EPCs-treated SHR rats compared with the control rats 5 weeks after MCAO (P&lt;0.05). The number of bromodeoxyuridine+/CD31+ microvessels are significantly increased. EPCs migration and proliferation were promoted after miR-126 modified in vitro. Conclusions: Our results showed that miR-126 modified EPCs therapyreduced ischemic brain injury, along with increased angiogenesis and neurogenesis in SHR rats, suggesting miR-126 significantly improved EPCs function in angiogenesis after MCAO. Gene modified EPCs represents a promising avenue for ischemic stroke stem cell therapy.

MeCP2 mediated dysfunction in senescent EPCs.

Aging endothelial progenitor cells (EPCs) exhibit functional impairment in terms of proliferation, migration and survival. SIRT1 plays an important role in improving EPCs function. MeCP2, another important epigenetic regulator, is involved in regulating many life-related activities such as cell growth, death and senescence. Here we aim to explore the effect of MeCP2 on the functional activities of senescent EPCs and the underlying mechanisms. By using western blot and real-time PCR, we found that the expression levels of MeCP2 were up-regulated and SIRT1 were down-regulated with replicative senescence and H2O2-induced senescence. Through transduction with adenoviral vectors, EPCs overexpressing MeCP2 had significantly reduced EPCs function, and silencing MeCP2 improved EPCs function. In addition, the protein and mRNA levels of SIRT1 were decreased with MeCP2 overexpression and increased with MeCP2 knockdown. Through co-transfection of EPCs with MeCP2 and SIRT1, we observed that SIRT1 could reverse the effects of MeCP2 on EPCs. In summary, our work demonstrated that MeCP2 inhibited SIRT1 in senescent EPCs.

OP.1B.06] MIR-126 MODIFIED ENDOTHELIAL PROGENITOR CELLS TRANSPLANTATION CONTRIBUTES TO ANGIOGENESIS AFTER BRAIN FOCAL ISCHEMIA IN SHR RATS

Objective: Transplantation of endothelial progenitor cells (EPCs) leads to better outcomes in experimental stroke, while improve the EPCs survival rate in ischemia area is still a challenge. MiR-126 modulates vascular development and angiogenesis. Here we overexpressed miR-126 in transplanted EPCs, to investigate the function of gene modified EPCs in angiogenesis after brain ischemia. Design and method: Adult male SHR rats underwent permanent suture middle cerebral artery occlusion (MCAO). One week after middle cerebral artery occlusion, the animals received tail vein injection of miR-126 modified EPCs as treatment or EPCs as control and were monitored for 5 weeks. Brain water content, infarct volume, neurological score, neurogenesis and angiogenesis were examined. Results: Neurological score was greatly improved and brain atrophy was greatly reduced in miR-126 modified EPCs-treated SHR rats compared with the control rats 5 weeks after MCAO (P < 0.05). The number of bromodeoxyuridine+/CD31+ microvessels are significantly increased. EPCs migration and proliferation were promoted after miR-126 modified in vitro. Conclusions: Our results showed that miR-126 modified EPCs therapy reduced ischemic brain injury, along with increased angiogenesis and neurogenesis in SHR rats, suggesting miR-126 significantly improved EPCs function in angiogenesis after MCAO. Gene modified EPCs represents a promising avenue for ischemic stroke stem cell therapy.

Attenuation of neointimal formation with netrin-1 and netrin-1 preconditioned endothelial progenitor cells.

Netrin-1 attenuates neointimal formation following post endothelial injury via DCC and NO. Netrin-1 inhibits VSMC proliferation in situ following endothelial injury. Netrin-1 inhibits VSMC migration via a NO/cGMP/p38 MAPK pathway. Netrin-1 augments proliferation of endothelial progenitor cells (EPCs) and EPC eNOS/NO activation. Netrin-1 enhances resistance of EPCs to oxidative stress, improving re-endothelialization following injury.

Exercise training-induced different improvement profile of endothelial progenitor cells function in mice with or without myocardial infarction

BackgroundNeovascularization in response to ischemia after myocardial infarction (MI) has been widely considered as being initiated by endothelial progenitor cells (EPCs). Well-documented evidences in recent years have proved exercise training (ET) improving EPC function. However, whether ET-induced improvement of EPC function under or without ischemic state is different has not been reported. MethodsMice performed ET following an exercise prescription 1week after MI or non-MI surgery respectively. Bone marrow-derived EPCs were isolated at 0day, 3days, 1week, 2weeks, 4weeks, and 8weeks of ET. After 7days cultivation, EPC functions including proliferation, adhesion, migration, and in vitro angiogenesis were measured. AKT/glycogen synthase kinase 3β (GSK3β) signaling pathway was tested by western blotting. ResultsEPC function in mice underwent non-MI surgery was attenuated overtime, while ET ameliorated this tendency. EPC function was peaked at 4weeks ET in non-MI surgery mice and maintained with an extended exercise time. Besides, simple ischemia was sufficient to enhanced EPC function, with a maximum at 2weeks of MI surgery. In MI mice, ET further improved EPC function and achieved peak at 2weeks exercise. Furthermore, AKT/GSK3β signaling pathway activation was consistent with EPC function change after ischemia, which was further promoted by 4weeks exercise. ConclusionET significantly increased EPC function in mice both with and without MI, but the time points of peak function were different.

Irisin Increased the Number and Improved the Function of Endothelial Progenitor Cells in Diabetes Mellitus Mice.

:The dysfunction of endothelial progenitor cells (EPCs) was found to be associated with vascular complications in diabetes mellitus (DM) patients. Previous studies found that regular exercise could improve the function of EPCs in DM patients, but the underling mechanism was unclear. Irisin, a newly identified myokine, was induced by exercise and has been demonstrated to mediate some of the positive effects of exercise. In this study, we hypothesize that irisin may have direct effects on EPC function in DM mice. These data showed for the first time that irisin increased the number of EPCs in peripheral blood of DM mice and improved the function of EPCs derived from DM mice bone marrow. The mechanism for the effect of irisin is related to the PI3K/Akt/eNOS pathway. Furthermore, irisin was demonstrated to improve endothelial repair in DM mice that received EPC transplants after carotid artery injury. The results of this study indicate a novel effect of irisin in regulating the number and function of EPCs via the PI3K/Akt/eNOS pathway, suggesting a potential for the administration of exogenous irisin as a succedaneum to improve EPC function in diabetic patients who fail to achieve such improvements through regular exercise.

Diazoxide accelerates wound healing by improving EPC function.

Endothelial cell dysfunction is the primary cause of microvascular complications in diabetes. Diazoxide enables beta cells to rest by reversibly suppressing glucose-induced insulin secretion by opening ATP-sensitive K+ channels in the beta cells. This study investigated the role of diazoxide in wound healing in mice with streptozotocin (STZ)-induced diabetes and explored the possible mechanisms of its effect. Compared to the controls, mice with STZ-induced diabetes exhibited significantly impaired wound healing. Diazoxide treatment (30 mg/kg/d, intragastrically) for 28 days accelerated wound closure and stimulated angiogenesis in the diabetic mice. Circulating endothelial progenitor cells (EPCs) increased significantly in the diazoxide-treated diabetic mice. The adhesion, migration, and tube formation abilities of bone marrow (BM)-EPCs were impaired by diabetes, and these impairments were improved by diazoxide treatment. The expression of both p53 and TSP-1 increased in diabetic mice compared to that in the controls, and these increases were inhibited significantly by diazoxide treatment. In vitro, diazoxide treatment improved the impaired BM-EPC function and diminished the increased expression of p53 and TSP-1 in cultured BM-EPCs caused by high glucose levels. We conclude that diazoxide improved BM-EPC function in mice with STZ-induced diabetes, possibly via a p53- and TSP-1-dependent pathway.

Tripterine Treatment Improves Endothelial Progenitor Cell Function via Integrin-Linked Kinase

Background/Aims: Atherosclerosis is associated with dysfunction of endothelial progenitor cells (EPCs). Tripterine, a chemical compound derived from the Chinese medicinal plant Tripterygium wilfordii Hook, displays anti-inflammatory properties in several animal models. We hypothesized that tripterine can improve EPC function and thus the efficiency of EPC transplantation. Methods and Results: Tripterine preconditioning (2.5 μM, 4 h) improved EPC proliferation, tube formation, migration, and adhesion, and reduced apoptosis in cells cultured in ox-LDL (200 µg/ml). Tripterine restored integrin-linked kinase (ILK) levels downregulated by ox-LDL in EPCs, suggesting the involvement of the ILK/Akt pathway. Small interfering RNA-mediated depletion of ILK and dominant-negative ILK transduction inhibited the phosphorylation of the ILK downstream signaling targets protein kinase B/Akt and glycogen synthase kinase 3-beta (GSK-3β), and reduced β-catenin and cyclin D1 expression. In atherosclerotic mice injected with green fluorescent protein-labeled EPCs to evaluate EPC function, tripterine decreased aortic lesions and plaque deposition, and injection of tripterine-treated EPCs restored ILK levels. Conclusion: The present results suggest that tripterine improves vascular function in atherosclerosis by enhancing EPC function through a mechanism involving the ILK signaling pathway.

Interleukin-10 overexpression improves the function of endothelial progenitor cells stimulated with TNF-α through the activation of the STAT3 signaling pathway.

Lentivirus vector-interleukin-10 green fluorescent protein (LV-IL-10-GFP) was transfected into endothelial progenitor cells (EPCs) in the present study. The aim was to detect the function of IL‑10‑modified EPCs and analyze the molecular mechanism. EPCs were cultured and identified by fluorescent labeling with the von Willebrand factor antibody, vascular endothelial growth factor (VEGF) receptor, Ulex europaeus agglutinin-1 and acetylated low‑density lipoprotein. Subsequently, EPCs were transfected with LV-IL-10-GFP and lentivirus vector‑noncontain‑GFP as the control group. Enzyme‑linked immunosorbent assay (ELISA) was used to detect the concentrations of cytokines in the supernatant with or without tumor necrosis factor‑α (TNF‑α). All types of cells were assessed by a tube formation assay, adhesion assay and migration assay induced with or without TNF‑α. Cell cycle was assessed by flow cytometry. Western blot analysis was applied to detect the expression of proteins in the cells. ELISA analysis showed that the levels of TNF‑α and IL‑8 in the supernatant without TNF‑α significantly decreased in EPC‑LV‑IL‑10‑GFP (P<0.05 for all). By contrast, the levels of IL‑10 and VEGF were contrasting in association with these. The concentrations of cytokines in the supernatant with TNF‑α were consistent to the supernatant without TNF‑α. There was no statistically significant difference in the average number of EPCs undergoing migration, adhesion, total length and cell growth among the EPC, EPC‑LV‑IL‑10‑GFP and EPC‑LV‑NC‑GFP groups without TNF‑α. Further study showed that EPC‑LV‑IL‑10‑GFP with TNF‑α significantly enhanced EPC migration, adhesion and promoted tube formation (P<0.05 for all). Western blot analysis revealed that the expression of VEGF, matrix metallopeptidase‑9 and phosphorylated‑signal transducer and activator of transcription 3 (p‑STAT3) significantly increased in the EPC‑LV‑IL‑10‑GFP group. Conversely, STAT‑3 expression decreased in the EPC‑LV‑IL‑10‑GFP group. The present study suggested that overexpression of IL‑10 had no effect on migration, adhesion, tubule formation and cell growth of EPCs without TNF‑α. Furthermore, in EPCs stimulated with TNF‑α, the overexpression of IL‑10 improved EPC function, including migration, adhesion and tubule formation by activating the STAT3 signal pathway.

Activation of liver X receptor enhances the proliferation and migration of endothelial progenitor cells and promotes vascular repair through PI3K/Akt/eNOS signaling pathway activation

Vascular endothelial injury is a major cause of many cardiovascular diseases. The proliferation and migration of endothelial progenitor cells (EPCs) play a pivotal role in endothelial regeneration and repair after vascular injury. Recently, liver X receptor (LXR) activation has been suggested as a potential target for novel therapeutic interventions in the treatment of cardiovascular disease. However, the effects of LXR activation on endothelial regeneration and repair, as well as EPC function, have not been investigated. In the present study, we demonstrate that LXRs, including LXRα and LXRβ, are expressed and functional in rat bone marrow-derived EPCs. Treatment with an LXR agonist, TO901317 (TO) or GW3965 (GW), significantly increased the proliferation and migration of EPCs, as well as Akt and eNOS phosphorylation in EPCs. Moreover, LXR agonist treatment enhanced the expression and secretion of vascular endothelial growth factor in EPCs. LXR agonists accelerated re-endothelialization in injured mouse carotid arteries in vivo. These data confirm that LXR activation may improve EPC function and endothelial regeneration and repair after vascular injury by activating the PI3K/Akt/eNOS pathway. We conclude that LXRs may be attractive targets for drug development in the treatment of cardiovascular diseases associated with vascular injury.

Bone Marrow Rejuvenation Accelerates Re-Endothelialization and Attenuates Intimal Hyperplasia After Vascular Injury in Aging Mice

Aging-associated functional impairment of endothelial progenitor cells (EPCs) contributes to delayed re-endothelialization after vascular injury and exaggerated intimal hyperplasia (IH). This study tested if bone marrow (BM) rejuvenation accelerates post-injury re-endothelialization in aging mice. Using BM transplantation (BMT(Gfp→Wild)), young(Gfp) to young(Wild) (YTY), old(Gfp) to old(Wild) (OTO), young(Gfp) to old(Wild) (YTO), and old(Gfp) to young(Wild) (OTY) groups were created. After vascular injury, IH was significantly greater in the old group than the young group (P<0.001). BM rejuvenation (YTO) significantly accelerated re-endothelialization and attenuated IH. Compared with the OTO group, the YTY and YTO groups had earlier and greater EPC-derived re-endothelialization (P<0.001). The number of Sca-1(+)KDR(+) EPCs mobilized in the circulation induced by vascular injury was higher in young, YTO, and YTY mice than in old mice (P<0.05). Sca-1(+) BM cells from the young, YTO, and YTY groups had better migration and adhesion capacities than those from the old group (P<0.05). The increase in blood vascular endothelial growth factor (VEGF) levels after vascular injury was higher in young than in old mice. PI3K, Akt, and FAK pathways played a pivotal role in VEGF-associated EPC migration. Specifically, EPCs from young and YTO mice, compared with old mice, demonstrated stronger FAK phosphorylation after VEGF stimulation. EPCs play a critical role in vascular repair in aging mice. BM rejuvenation accelerates re-endothelialization by improving EPC function.

Critical role of the nitric oxide/reactive oxygen species balance in endothelial progenitor dysfunction.

Endothelial injury and dysfunction are critical events in the pathogenesis of cardiovascular disease. During these processes, an impaired balance of nitric oxide bioavailability and oxidative stress is mechanistically involved. Circulating angiogenic cells (including early and late outgrowth endothelial progenitor cells (EPC)) contribute to formation of new blood vessels, neovascularization, and homeostasis of the vasculature, and are highly sensitive for misbalance between NO and oxidative stress. We here review the role of the endothelial nitric oxide synthase and oxidative stress producing enzyme systems in EPC during cardiovascular disease. We also focus on the underlying molecular mechanisms and potential emerging drug- and gene-based therapeutic strategies to improve EPC function in cardiovascular diseased patients.

Impairment of endothelial progenitor cell function and vascularization capacity by aldosterone in mice and humans

AimsHyperaldosteronism is associated with vascular injury and increased cardiovascular events. Bone marrow-derived endothelial progenitor cells (EPCs) play an important role in endothelial repair and vascular homeostasis. We hypothesized that hyperaldosteronism impairs EPC function and vascularization capacity in mice and humans.Methods and resultsWe characterized the effects of aldosterone and mineralocorticoid receptor (MR) blockade on EPC number and function as well as vascularization capacity and endothelial function. Treatment of human EPC with aldosterone induced translocation of the MR and impaired multiple cellular functions of EPC, such as differentiation, migration, and proliferation in vitro. Impaired EPC function was rescued by pharmacological blockade or genetic ablation of the MR. Aldosterone protein kinase A (PKA) dependently increased reactive oxygen species formation in EPC. Aldosterone infusion in mice impaired EPC function, EPC homing to vascular structures and vascularization capacity in a MR-dependent but blood pressure-independent manner. Endothelial progenitor cells from patients with primary hyperaldosteronism compared with controls of similar age displayed reduced migratory potential. Impaired EPC function was associated with endothelial dysfunction. MR blockade in patients with hyperaldosteronism improved EPC function and arterial stiffness.ConclusionEndothelial progenitor cells express a MR that mediates functional impairment by PKA-dependent increase of reactive oxygen species. Normalization of EPC function may represent a novel mechanism contributing to the beneficial effects of MR blockade in cardiovascular disease prevention and treatment.