Angiopoietin-1 protects heart against ischemia/reperfusion injury through VE-cadherin dephosphorylation and myocardiac integrin-β1/ERK/caspase-9 phosphorylation cascade

Early reperfusion after myocardial ischemia that is essential for tissue salvage also causes myocardial and vascular injury. Cardioprotection during reperfusion therapy is an essential aspect of treating myocardial infarction. Angiopoietin-1 is an endothelial-specific angiogenic factor. The potential effects of angiopoietin-1 on cardiomyocytes and vascular cells undergoing reperfusion have not been investigated. We propose a protective mechanism whereby angiopoietin-1 increases the integrity of the endothelial lining and exerts a direct survival effect on cardiomyocytes under myocardial ischemia followed by reperfusion. First, we found that angiopoietin-1 prevents vascular leakage through regulating vascular endothelial (VE)-cadherin phosphorylation. The membrane expression of VE-cadherin was markedly decreased on hypoxia/reoxygenation but was restored by angiopoietin-1 treatment. Interestingly, these effects were mediated by the facilitated binding between SH2 domain-containing tyrosine phosphatase (SHP2) or receptor protein tyrosine phosphatase μ (PTPμ) and VE-cadherin, leading to dephosphorylation of VE-cadherin. siRNA against SHP2 or PTPμ abolished the effect of angiopoietin-1 on VE-cadherin dephosphorylation and thereby decreased levels of membrane-localized VE-cadherin. Second, we found that angiopoietin-1 prevented cardiomyocyte death, although cardiomyocytes lack the angiopoietin-1 receptor Tie2. Angiopoietin-1 increased cardiomyocyte survival through integrin-β1-mediated extracellular signal-regulated kinase (ERK) phosphorylation, which inhibited caspase-9 through phosphorylation at Thr¹²⁵ and subsequently reduced active caspase-3. Neutralizing antibody against integrin-β1 blocked these protective effects. In a mouse myocardial ischemia/reperfusion model, angiopoietin-1 enhanced cardiac function and reduction in left ventricular-end systolic dimension (LV-ESD) and left ventricular-end diastolic dimension (LV-EDD) with an increase in ejection fraction (EF) and fractional shortening (FS). Our findings suggest the novel cardioprotective mechanisms of angiopoietin-1 that are achieved by reducing both vascular leakage and cardiomyocyte death after ischemia/reperfusion injury.

Creation of myocardial fibrosis by transplantation of fibroblasts primed with survival factors

One of the major obstacles in the creation of myocardial fibrosis using fibroblasts is massive cell death after cell injection. To overcome this problem, a method that delivers fibroblasts primed with survival factors was studied. Cardiac fibroblasts were isolated from wild-type male C57BL/6 mice. Female mice were randomly placed into the following three groups: 1) fibroblasts transfected with β-galactosidase-containing adenovirus (control group), 2) fibroblasts treated with a necrosis inhibitor (NI group), and 3) fibroblasts transfected with Akt-containing adenovirus (Akt group). Pretreated cells were transplanted into the recipient heart by direct injection after a thoracotomy. Quantitative real-time PCR and morphometric analysis were performed to investigate the effects of survival factor priming on the induction of cell engraftment and fibrosis. In addition, a canine model was used to investigate the development of fibrosis and conduction modification using autologous dermal fibroblasts. The NI and Akt groups showed a better engraftment rate: 13 (NI group) and 7 (Akt group) times greater at 21 days compared with the control group. Increased fibrosis and conduction delay were also observed in the NI and Akt groups compared with the control group. Survival factor priming increased cellular engraftment and enhanced the efficacy of cell transplantation. Delivery of fibroblasts primed with survival factors might be a promising approach to develop conduction modification as a novel strategy to treat arrhythmias.

Malignant tumor formation after transplantation of short-term cultured bone marrow mesenchymal stem cells in experimental myocardial infarction and diabetic neuropathy

RATIONALE

Bone marrow (BM)-derived mesenchymal stem cells (MSCs) hold great promise for cardiovascular cell therapy owing to their multipotency and culture expandability.

OBJECTIVE

The aim of the study was to investigate whether MSCs can treat experimental acute myocardial infarction (MI) and diabetic neuropathy.

METHODS AND RESULTS

We isolated mononuclear cells from mouse BM and cultured MSCs in a conventional manner. Flow cytometry analyses of these cultured cells at passage 4 showed expression of typical MSC markers such as CD44 and CD29, but not hematopoietic markers such as c-kit, flk1, and CD34. To determine the therapeutic effects of MSCs, we injected MSCs into the peri-infarct area after ligation of the left anterior descending coronary arteries of mice and, as separate experiments, injected the same batch of MSCs into hindlimb muscles of mice with diabetic neuropathy. During the follow-up at 4 to 8 weeks after cell transplantation, growing tumors were observed in 30% of hearts in the MI model, and in 46% of hindlimbs in the diabetic neuropathy model. Histological examination of the tumors revealed hypercelluarity, pleomorphic nucleoli, cytological atypia and necrosis, and positive staining for α-smooth muscle actin, indicative of malignant sarcoma with myogenic differentiation. Chromosomal analysis of these MSCs showed multiple chromosomal aberrations including fusion, fragmentation, and ring formation.

CONCLUSIONS

Genetically unmodified MSCs can undergo chromosomal abnormalities even at early passages and form malignant tumors when transplanted in vivo. These results suggest that careful monitoring of chromosomal status is warranted when in vitro expanded MSCs are used for cell therapy such as for MI.

Carriage of the V279F null allele within the gene encoding Lp-PLA₂ is protective from coronary artery disease in South Korean males

Background

The Asia-specific PLA2G7 994G-T transversion leads to V279F substitution within the lipoprotein-associated phospholipase-A2 (Lp-PLA₂) and to absence of enzyme activity in plasma. This variant offers a unique natural experiment to assess the role of Lp-PLA₂ in the pathogenesis of coronary artery disease (CAD) in humans. Given conflicting results from mostly small studies, a large two-stage case-control study was warranted.

Methodology/Principal Findings

PLA2G7 V279F genotypes were initially compared in 2890 male cases diagnosed with CAD before age 60 with 3128 male controls without CAD at age 50 and above and subsequently in a second independent male dataset of 877 CAD cases and 1230 controls. In the first dataset, the prevalence of the 279F null allele was 11.5% in cases and 12.8% in controls. After adjustment for age, body mass index, diabetes, smoking, glucose and lipid levels, the OR (95% CI) for CAD for this allele was 0.80 (0.66–0.97, p = 0.02). The results were very similar in the second dataset, despite lower power, with an allele frequency of 11.2% in cases and 12.5% in controls, leading to a combined OR of 0.80 (0.69–0.92), p = 0.002. The magnitude and direction of this genetic effect were fully consistent with large epidemiological studies on plasma Lp-PLA₂ activity and CAD risk.

Conclusions

Natural deficiency in Lp-PLA₂ activity due to carriage of PLA2G7 279F allele protects from CAD in Korean men. These results provide evidence for a causal relationship between Lp-PLA₂ and CAD, and support pharmacological inhibition of this enzyme as an innovative way to prevent CAD.

Adipokine resistin is a key player to modulate monocytes, endothelial cells, and smooth muscle cells, leading to progression of atherosclerosis in rabbit carotid artery

OBJECTIVES

We investigated the effects of human resistin on atherosclerotic progression and clarified its underlying mechanisms.

BACKGROUND

Resistin is an adipokine first identified as a mediator of insulin resistance in murine obesity models. But, its role in human pathology is under debate. Although a few recent studies suggested the relationship between resistin and atherosclerosis in humans, the causal relationship and underlying mechanism have not been clarified.

METHODS

We cloned rabbit resistin, which showed 78% identity to human resistin at the complementary deoxyribonucleic acid level, and its expression was examined in 3 different atherosclerotic rabbit models. To evaluate direct role of resistin on atherosclerosis, collared rabbit carotid arteries were used. Histological and cell biologic analyses were performed.

RESULTS

Rabbit resistin was expressed by macrophages of the plaque in the 3 different atherosclerotic models. Peri-adventitial resistin gene transfer induced macrophage infiltration and expression of various inflammatory cytokines, resulting in the acceleration of plaque growth and destabilization. In vitro experiments elucidated that resistin increased monocyte-endothelial cell adhesion by upregulating very late antigen-4 on monocytes and their counterpart vascular cell adhesion molecule-1 on endothelial cells. Resistin augmented monocyte infiltration in collagen by direct chemoattractive effect as well as by enhancing migration toward monocyte chemotactic protein-1. Administration of connecting segment-1 peptide, which blocks very late antigen-4 × vascular cell adhesion molecule-1 interaction, ameliorated neointimal growth induced by resistin in vivo.

CONCLUSIONS

Our results indicate that resistin aggravates atherosclerosis by stimulating monocytes, endothelial cells, and vascular smooth muscle cells to induce vascular inflammation. These findings provide the first insight on the causal relationship between resistin and atherosclerosis.

Effect of warfarin withdrawal on thrombolytic treatment in patients with ischaemic stroke

BACKGROUND AND PURPOSE

  Abruptly discontinuing warfarin may induce a rebound prothrombotic state. Thrombolytic agents may also paradoxically induce prothrombotic conditions, which include platelet activation and thrombin generation. Therefore, prothrombotic states may be enhanced by withdrawing warfarin in patients under thrombolytic treatment. This study was aimed to determine whether patients with warfarin withdrawal have different clinical outcomes from those without warfarin use after thrombolytic treatment.

METHODS

  A total of 148 consecutive patients with atrial fibrillation who were not on anticoagulants at admission and who received thrombolysis were included in this study. We compared the outcomes between a warfarin withdrawal group and a no-warfarin group.

RESULTS

  Fourteen patients (9.5%) were included in the warfarin withdrawal group. Although baseline National Institute of Health Stroke Scale (NIHSS) scores, recanalization rates, and hemorrhage frequencies did not differ between the groups, the warfarin withdrawal group showed poorer outcomes. Increased NIHSS scores during the first 7days were more frequent in the warfarin withdrawal group (57.1% vs. 26.9%, P=0.029). The median percent improvement in NIHSS scores at 24h after thrombolysis was also lower in the warfarin withdrawal group. After adjusting for covariates, warfarin withdrawal was a strong predictor of poor functional outcome at 3months (modified Rankin score≥3) (odds ratio, 17.067, 95% CI 2.703-107.748).

CONCLUSIONS

  Discontinuing warfarin was associated with early neurologic deterioration and poor long-term outcomes after thrombolytic treatment.

Analysis of differential proteomes of induced pluripotent stem cells by protein-based reprogramming of fibroblasts

The recent generation of induced pluripotent stem (iPS) cells represents a novel opportunity to complement embryonic stem (ES) cell-based approaches. iPS cells can be generated by viral transduction of specific transcription factors, but there is a potential risk of tumorigenicity by random retroviral integration. We have generated novel iPS (sFB-protein-iPS) cells from murine dermal fibroblasts (FVB-sFB) that have ES cell characteristics, using ES cell-derived cell extracts instead of performing viral transduction. Notably, only cell extracts from an ES cell line (C57-mES) on the C57/BL6 background generated iPS cells in our protocol-not an ES cell line (E14-mES) on the 129 background. Hypothesizing that determining the differences in these 2 mES cell lines will provide vital insight into the reprogramming machinery, we performed proteomic and global gene expression analysis by iTRAQ and mRNA microarray, respectively. We observed that pluripotent ES cells and ES cell extract-derived iPS cells had differential proteomes and global gene expression patterns. Notably, reprogramming-competent C57-mES cells highly expressed proteins that regulate protein synthesis and metabolism, compared with reprogramming-incompetent 129-mES cells, suggesting that there is a threshold that protein synthetic machinery must exceed to initiate reprogramming.

Cryopreservation of human embryonic stem cells derived-cardiomyocytes induced by BMP2 in serum-free condition

Although previous studies showed that cardiomyocytes (CMs) can be generated from human embryonic stem cells (hESCs), the protocols for cryopreservation of hESC-derived CMs is not available to date. Here, we report on the efficient generation of hESC-derived CMs by direct differentiation using BMP2 in a serum-free condition, along with successful cryopreservation of derived CMs using Rho-associated kinase (ROCK) inhibitor. To induce differentiation, hESCs were treated with activin A and BMP2 for 5 days. A mesodermal gene, Brachyury, was expressed from day 3, and cardiac-specific markers such as Nkx2.5 and cTnI were detected at day 14. Furthermore, these cardiac progenitors expressed ion channel-related transcripts such as HCN1 and HCN2 from day 10. Beating clusters were observed from 14 days of differentiation for up to 35 days. Using mass cryopreservation, we froze hESC-derived CMs at 2 stages, at day 12 and 16 (prebeating and postbeating), after treating with ROCK inhibitor, Y-27632. Postthaw survival of CMs was higher in day 12 group compared to day 16, and some cell clusters from day 12 group recovered their contraction. From transmission electron microscope (TEM) analysis, less ultrastructural alterations were observed in day 12 group. Our results provide an insight into the use of BMP2 for cardiac lineage differentiation in a serum-free condition and a possibility of long-term storage of hESC-derived CMs.

The different infarct patterns between adulthood-onset and childhood-onset moyamoya disease

BACKGROUND AND PURPOSE

The pattern of infarctions based on the findings of diffusion-weighted image was assessed, and it was also investigated whether there are any age-specific differences in patients with moyamoya disease (MMD).

METHODS

The subjects were 66 consecutive patients with MMD who had an acute cerebral infarction. Each ischaemic lesion was categorised into one of seven patterns (gyral, atypical territorial, honeycomb, classic territorial, multiple-dot, borderzone, deep lacunar) based on diffusion-weighted image findings. The patterns were compared between adulthood-onset MMD (A-MMD, ≥20 years old, 34 patients) and childhood/adolescent-onset MMD (C-MMD, <20 years old, 32 patients) according to their ages of infarct presentation.

RESULTS

A total of 91 infarct patterns were observed from 66 patients. The gyral, atypical territorial, and honeycomb patterns, which are not usually seen in conventional stroke patients, were common in MMD (68.1%). Among all patterns, a gyral pattern was most common (40/91, 44.0%). Borderzone and deep lacunar patterns were infrequent. Gyral and borderzone patterns were more frequently seen in the C-MMD group, whereas a honeycomb pattern was not seen in young patients. Honeycomb pattern was more common at advanced vascular stages. Infarctions confined to the cortex were more common in the C-MMD group (26/32, 75.0%) than in A-MMD patients (14/34, 41.2%).

CONCLUSIONS

Moyamoya disease showed various characteristic and age-specific infarct patterns. Different infarct patterns between the A-MMD and C-MMD groups may be associated with age-specific vulnerability of the brain to ischaemia, stage of arteriopathy or changes of abnormal collateral pathways.

Implementation of Consolidated HIS: Improving Quality and Efficiency of Healthcare

Objectives

Adoption of hospital information systems offers distinctive advantages in healthcare delivery. First, implementation of consolidated hospital information system in Seoul National University Hospital led to significant improvements in quality of healthcare and efficiency of hospital management.

Methods

The hospital information system in Seoul National University Hospital consists of component applications: clinical information systems, clinical research support systems, administrative information systems, management information systems, education support systems, and referral systems that operate to generate utmost performance when delivering healthcare services.

Results

Clinical information systems, which consist of such applications as electronic medical records, picture archiving and communication systems, primarily support clinical activities. Clinical research support system provides valuable resources supporting various aspects of clinical activities, ranging from management of clinical laboratory tests to establishing care-giving procedures.

Conclusions

Seoul National University Hospital strives to move its hospital information system to a whole new level, which enables customized healthcare service and fulfills individual requirements. The current information strategy is being formulated as an initial step of development, promoting the establishment of next-generation hospital information system.

Novel embryoid body-based method to derive mesenchymal stem cells from human embryonic stem cells

Application of human embryonic stem cells (hESCs) to stem-cell therapy is not feasible because of the risk of tumorigenicity and rejection. In contrast, human mesenchymal stem cells (hMSCs) are free from the risk of tumorigenicity and also have immune privilege. However, hMSCs obtained from adults have infinite variety in terms of the biological characteristics and functionality. We report here a new derivation method of hMSCs from hESCs. The derivation of hMSCs from three different hESC lines (SNUhES3, CHA3-hESC, and H9) was performed by embryoid bodies formation and subsequent culture with stage-different media without using inductive xenogenic feeder and mechanical selection procedure. The derived cells were morphologically similar to the unique fingerprint-like pattern of hMSCs and grew stably for at least 35 passages in vitro. These cells had hMSCs-like immunophenotypes: negative for CD34 and CD45; positive for CD29, CD44, CD73, CD90, and CD105. They could be differentiated into multiple lineages including osteocytes, chondrocytes, adipocytes, and myocytes. They maintained normal karyotype during the long-term cultivation and did not show tumorigenicity when transplanted into the immunodeficient mice. In conclusion, the new embryoid body-based derivation method of hMSCs from hESCs is simple, safe, and reproducible in three different hESC lines. We expect that this method will provide a more effective and powerful tool to derive hMSCs from various hESC lines.

Human peripheral blood-derived CD31+ cells have robust angiogenic and vasculogenic properties and are effective for treating ischemic vascular disease

OBJECTIVES

This study aimed to determine if CD31 is a novel marker of a circulating angio-vasculogenic cell population and to establish the cells' therapeutic effects on experimental ischemia.

BACKGROUND

Emerging evidence suggested that therapeutic mechanisms underlying various bone marrow-derived cells are due to paracrine effects. Furthermore, the vasculogenic potential of these cells is under debate. CD31 is a well-known marker for endothelial cells but is also expressed in a fraction of peripheral blood (PB) mononuclear cells.

METHODS

CD31(+) cells were isolated from human PB by magnetic-activated cell sorting. The gene expression profile was examined by deoxyribonucleic acid microarray and real-time reverse transcriptase polymerase chain reaction. Various in vitro endothelial differentiation or vasculogenic assays were conducted. Finally, cells were directly implanted into a mouse hind limb ischemia model to test angiogenic-vasculogenic and therapeutic effects.

RESULTS

Fluorescent-activated cell sorter analysis revealed that PB-CD31(+) cells exhibited endothelial and hematopoietic stem/progenitor markers. CD31(+) cells had higher levels of expression of proangiogenic genes on microarray and real-time reverse transcriptase polymerase chain reaction and generated higher numbers of endothelial progenitor cells than CD31(-) cells did. CD31(+) cells spontaneously formed vascular tubelike structures and exhibited an endothelial cell phenotype in vitro. In a hind limb ischemia model, CD31(+) cell transplantation augmented blood perfusion and prevented limb loss. Both angiogenic cytokines and capillary density were increased, suggesting CD31(+) cells augmented neovascularization.

CONCLUSIONS

CD31 is a novel marker that designates circulating angiogenic and vasculogenic cells. These cells are easily isolated from human PB and thus are a novel candidate for treatment of ischemic cardiovascular disease.

Evaluation of the usefulness of the fetal femur length with respect to gestational age to detect Down syndrome in Korean subjects

OBJECTIVE

We investigated the usefulness of shortening of the fetal femur length (FL) to predict Down syndrome at different gestational ages in Korean subjects.

METHODS

This study involved 110 Korean Down syndrome fetuses and 602 randomly selected euploid controls. The expected FL for any biparietal diameter (BPD) was calculated based on the control group data. Subjects were divided into four groups according to gestational age periods: 14-18 weeks; 19-23 weeks; 24-28 weeks and 29-36 weeks. The value of measured/expected FL ratio to predict Down syndrome was analyzed for each group.

RESULTS

The values of FL for any BPD in Down syndrome patients were significantly different from those in the control group (p < 0.001). A low ratio of measured/expected FL increased the risk of fetal Down syndrome (p < 0.001) with a mean measured/expected FL in Down syndrome of 0.907 (SD 0.075). At a fixed false positive rate of 5%, the sensitivities of FL were lower than 32.8% (95% CI 0.705-0.915) in three second trimester groups, and 71.1% (95% CI 0.924-0.997) in the third trimester group.

CONCLUSION

Short FL is a poor marker of Down syndrome in the second trimester in Korean subject. It may be used as a screening marker only in the third trimester.

CD31+ cells represent highly angiogenic and vasculogenic cells in bone marrow: novel role of nonendothelial CD31+ cells in neovascularization and their therapeutic effects on ischemic vascular disease

RATIONALE

Bone marrow (BM) cells play an important role in physiological and therapeutic neovascularization. However, it remains unclear whether any specific uncultured BM cell populations have higher angiogenic and vasculogenic activities. Moreover, there has been controversy regarding the vasculogenic ability of BM cells.

OBJECTIVE

Preliminary flow cytometric analysis showed that CD31, traditionally a marker for endothelial cells, is expressed in certain nonendothelial BM mononuclear cells in both human and mouse. Based on the conserved CD31 expression in the axis of hematopoietic stem/progenitor cells (HSC/HPCs) to endothelial cells, we further sought to determine the comprehensive vasculogenic and angiogenic characteristics of human and mouse BM-derived CD31(+) cells.

METHODS AND RESULTS

Flow cytometric analysis demonstrated that all CD31(+) cells derived from BM were CD45(+) and expressed markers for both HSC/HPCs and endothelial cells. Comprehensive gene expression analyses revealed that BM-CD31(+) cells expressed higher levels of angiogenic genes than CD31(-) cells. Endothelial progenitor cells, as well as HSC/HPCs, were almost exclusively confined to the CD31(+) cell fraction, and culture of CD31(+) cells under defined conditions gave rise to endothelial cells. Finally, injection of CD31(+) cells into ischemic hindlimb repaired ischemia, increased expression of angiogenic and chemoattractive factors, and, in part, directly contributed to vasculogenesis, as demonstrated by both 3D confocal microscopy and flow cytometry.

CONCLUSIONS

These data indicate that BM-CD31(+) cells represent highly angiogenic and vasculogenic cells and can be a novel and highly promising source of cells for cell therapy to treat ischemic cardiovascular diseases.

Socioeconomic differentials in cause-specific mortality among 1.4 million South Korean public servants and their dependents

BACKGROUND

A growing number of investigations have explored the contribution of cause of death to socioeconomic inequalities in mortality in Europe and North America, but few such studies have been performed on Asian populations.

OBJECTIVES

To analyse the socioeconomic inequality of cause-specific death rates from both an absolute and relative perspective, and to evaluate the contribution of cause of death to total mortality inequality in South Korea.

METHODS

Data were obtained from public servant health insurance beneficiary records. 1,403,297 subjects aged 35-64 years were followed for 9 years. Health insurance premium levels were used as a socioeconomic position indicator. The outcome variables were all-cause, 11 broad causes and 41 specific causes of death. Mortality differentials were examined using cause-specific age-adjusted mortality, relative indices of inequality, and slope inequality indices.

RESULTS

Graded inverse associations between income and mortality were found for most, but not all, specific causes of death. The major contributors to income differentials in total mortality in men were liver disease (15.4%), stroke (12.8%), land transport accidents (10.0%), lung cancer (7.1%) and liver cancer (7.0%). In women, stroke (30.7%), diabetes (9.1%), land transport accidents (6.6%), liver cancer (6.0%) and liver disease (5.1%) were important. Conclusions The contribution of the cause of death to socioeconomic inequality in mortality in South Korea differed from Western countries. To develop a policy to reduce the magnitude of socioeconomic inequality, an understanding of the major causes of death that contribute to mortality inequality is required.

Identification of the KAI1 metastasis suppressor gene as a hypoxia target gene

KAI1 is a metastasis suppressor gene known to inhibit cancer metastasis without affecting primary tumorigenicity. Although KAI1 expression has been reported to undergo transcriptional regulation, how its expression is up- or down-regulated by specific upstream signaling pathways has not been studied in detail. In this study, we characterized the regulatory elements within the 500bp upstream region of mouse KAI1 gene and identified a functional hypoxia-response element (HRE) within the promoter region. Hypoxia-dependent induction of KAI1 was directly mediated by hypoxia-inducible factor (HIF)-1alpha binding on the promoter, which subsequently caused increased recruitment of RNA polymerase II for transcriptional activation. The failure of HIF-1alpha recruitment to the KAI1 promoter was observed in Hif-1alpha knockout mouse embryonic fibroblasts. Furthermore, KAI1 protein synthesis was markedly increased in ischemic tissues, suggesting that KAI1 is a hypoxia target gene in vivo.

Priming with angiopoietin-1 augments the vasculogenic potential of the peripheral blood stem cells mobilized with granulocyte colony-stimulating factor through a novel Tie2/Ets-1 pathway

BACKGROUND

The low engraftment rate of stem/progenitor cells infused via the intracoronary route to the ischemic myocardium is one of the most important factors limiting the efficacy of cell therapy. We investigated the concept of priming peripheral blood stem cells enriched by granulocyte colony-stimulating factor mobilization and apheresis ((mob)PBSCs) with angiopoietin-1 (Ang1), to enhance the engraftment into the ischemic tissue and neovasculogenic potential.

METHODS AND RESULTS

The expression of Tie2, the Ang1 receptor, was significantly higher in (mob)PBSCs than naïve peripheral blood mononuclear cells (19.2+/-3.0% versus 1.2+/-0.8% versus 1.2+/-0.2%; P<0.001 for (mob)PBSCs from acute myocardial infarction (AMI) patients with granulocyte colony-stimulating factor treatment for 3 days versus peripheral blood mononuclear cells from AMI patients versus peripheral blood mononuclear cells from stable angina patients). After 4 hours of cartilage oligomeric matrix protein (COMP)-Ang1 stimulation, (mob)PBSCs committed to the endothelial lineage with the induction of CD31 and VE-cadherin expression, mediated by Tie2/Ets-1 pathway. Priming of (mob)PBSCs with COMP-Ang1 induced the expression of alpha4beta1 and alpha5beta1 integrins, which are also Ets-1 downstream molecules, leading to enhanced adhesion to endothelial cells or fibronectin. In a rabbit ear ischemia/reperfusion model, priming of (mob)PBSCs with COMP-Ang1 improved first-pass engraftment to the distal vascular bed after intraarterial delivery. In a murine ischemic hind-limb model, intravascular delivery of primed (mob)PBSCs enhanced both engraftment and neovascularization.

CONCLUSIONS

The short-term priming with COMP-Ang1 may be a feasible and promising option to activate (mob)PBSCs by enhancing differentiation and adhesiveness and to improve the efficacy of cell therapy for ischemic diseases.

Comparison of the characteristics for in-hospital and out-of-hospital ischaemic strokes

BACKGROUND AND PURPOSE

Patients who are being admitted to a hospital due to diseases other than stroke may develop a stroke (in-hospital stroke; IHS).

METHODS

We enrolled 111 consecutive patients who developed IHS outside a neurology ward during a 5-year period at a single hospital. The frequency, characteristics, and outcomes for IHS patients were compared with patients who develop ischaemic stroke outside of the hospital (out-of-hospital stroke; OHS).

RESULTS

Forty-six percent of IHS occurred in the department of cardiology or cardiovascular surgery and 60% were associated with surgery or procedures. In comparison with the OHS patient group, the IHS patient group showed an increased frequency of cardiac disease, leukocytosis, and anemia. Cardioembolism, stroke of other determined etiologies, and an incomplete evaluation were more common in the IHS group, whereas large artery atherosclerosis was more frequent in the OHS group. The IHS group had up to a 10-fold higher mortality than the OHS group, with sepsis being the most common cause of death in the IHS group.

CONCLUSIONS

IHS has distinct etiologies and stroke mechanisms from OHS. The prevention and management of infection could decrease mortality in IHS patients.

KITENIN recruits Dishevelled/PKC delta to form a functional complex and controls the migration and invasiveness of colorectal cancer cells

BACKGROUND AND AIMS

KITENIN was previously reported to promote metastasis in mouse colon tumour models; however, the signalling mechanism of KITENIN at the cellular level was unknown. Here the functional role of KITENIN with respect to colorectal cancer (CRC) cell invasion and its expression in CRC tissues were investigated.

METHODS

The effect of KITENIN on cell motility was analysed in a migration and invasion assay upon its overexpression and knockdown. Immunoprecipitation was used to elucidate binding partners, and immunohistochemistry was used to study expression levels.

RESULTS

KITENIN overexpression enhanced the migration of rat intestinal epithelial cells, whereas a loss of invasiveness was observed in CRC cells after KITENIN knockdown. Mechanically, KITENIN served as a scaffolding molecule that simultaneously recruited both Dishevelled (Dvl) and protein kinase C delta (PKC delta) through the membrane-spanning C-terminal region to form a complex that stimulated extracellular signal-regulated kinase (ERK)/activating protein-1 (AP-1) via a PKC delta component but also organised the actin filament via a Dvl component. The KITENIN complex controlled the invasiveness of CRC cells aetiologically harbouring various mutations in APC, beta-catenin or K-ras, in which AP-1 activation is redundant but the organisation of the actin filament is indispensable for cell motility. Clinically, KITENIN expression was significantly higher in colon cancer tissues from advanced stage (III, IV) than that of stage I CRC and also in corresponding metastatic tissues.

CONCLUSIONS

The functional KITENIN complex acts as an executor with regard to cell motility and thereby controls CRC cell invasion, which may contribute to promoting metastasis.