Platelet Angiopoietin-1 Protects Against Murine Models of Tumor Metastasis.

BACKGROUND: In addition to their fundamental roles in preserving vascular integrity, platelets also contribute to tumor angiogenesis and metastasis. However, despite being a reservoir for angiogenic and metastatic cytokines, platelets also harbor negative regulators of tumor progression. Angpt1 (angiopoietin-1) is a cytokine essential for developmental angiogenesis that also protects against tumor cell metastasis through an undefined mechanism. Although activated platelets release Angpt1 from α-granules into circulation, the contributions of platelet Angpt1 to tumor growth, angiogenesis, and metastasis have not been investigated. METHODS: Using cytokine arrays and ELISAs, we first compared platelet Angpt1 levels in breast and melanoma mouse tumor models to tumor-free controls. We then assessed tumor growth and metastasis in mice lacking megakaryocyte and platelet Angpt1 (Angpt1Plt KO). The spontaneous metastasis of mammary-injected tumor cells to the lungs was quantified using RT-PCR (reverse transcription-polymerase chain reaction). The lung colonization of intravenously injected tumor cells and tumor cell extravasation were determined using fluorescent microscopy and flow cytometry. RESULTS: Platelet Angpt1 is selectively upregulated in the PyMT (polyoma middle tumor antigen) breast cancer mouse model, and platelets are the principal source of Angpt1 in blood circulation. While primary tumor growth and angiogenesis were unaffected, Angpt1Plt KO mice had both increased spontaneous lung metastasis and tumor cell lung colonization following mammary or intravenous injection, respectively. Although platelet Angpt1 did not affect initial tumor cell entrapment in the lungs, Angpt1Plt KO mice had increased tumor cell retention and extravasation. Serum from Angpt1Plt KO mice increased endothelial permeability and reduced VE (vascular endothelial)-cadherin expression at endothelial junctions compared with serum from control mice (Angpt1WT). CONCLUSIONS: Platelets provide an intravascular source of Angpt1 that restrains tumor metastasis by preserving the lung microvasculature to limit tumor cell extravasation.

Angiopoietins as Predictor Indexes in COVID-19 Patients in Delta and Omicron Waves.

This study aimed to explore the correlation between Angiopoietin-1 (Ang-1) and Angiopoietin-2 (Ang-2) concentrations and the Angiopoietin-2/Angiopoietin-1 ratio (Ang-2/Ang-1) with clinical outcomes, potentially serving as disease severity and survival biomarkers. A study at AHEPA University Hospital involved 90 Coronavirus Disease 2019 (COVID-19) adult patients, 30 hospitalized intensive care units (ICU), 30 inward units (non-ICU), and 30 asymptomatic non-hospitalized individuals as controls. Estimated endothelial dysfunction markers related to angiogenesis were measured. There was a statistically significant difference only between outpatient and hospitalized patients (non-ICU-ICU groups) for the Ang-1 and Ang-2 indices. The Ang-2/Ang-1 ratio has differed significantly among the individual patient groups. An ROC analysis was conducted to find an optimal threshold for distinguishing between (outpatients-non-ICU) and (non-ICU-ICU) groups. It was based on Youden's index of 0.1122 and 0.3825, respectively. The Ang-1, Ang-2 levels, and Ang-2/Ang-1 ratio were analyzed as severity indicators in COVID-19 patients. The Ang-2/Ang-1 ratio demonstrated better prognostic and diagnostic utility than individual biomarker levels. Monitoring the Ang-2/Ang-1 ratio can identify COVID-19 patients at risk and assist clinicians in tailoring treatment strategies to improve outcomes.

Elucidating the molecular basis of PECAM-1 and Tie2 interaction from binding dynamics and complex formation.

BACKGROUND: Endothelial hyperpermeability-induced vascular dysfunction is a prevalent and significant characteristic in critical illnesses such as sepsis and other conditions marked by acute systemic inflammation. Platelet endothelial cell adhesion molecule-1 (PECAM-1) and Tie2 serve as transmembrane receptors within endothelial cells (ECs), playing pivotal roles not only in maintaining EC-EC junctions but also in influencing vasculogenesis, vessel homeostasis, and vascular remodeling. OBJECTIVES: At present, the molecular basis of the PECAM-1-Tie2 interaction remains inadequately elucidated. In the study, recombinant soluble PECAM-1 (sPECAM-1) and Tie2 (sTie2) were expressed by Drosophila S2 and HEK293 expression systems, respectively. The interactions between sPECAM-1 and sTie2 were investigated using the Surface Plasmon Resonance (SPR) and size-exclusion chromatography methods. An immunofluorescence assay was used to detect the binding of sPECAM-1 and sTie2 on endothelial cells. RESULTS: PECAM-1 was found to bind with sTie2 in a sodium and pH-dependent manner as confirmed by the ELISA, the D5-D6 domains of PECAM-1 might play a crucial role in binding with sTie2. Surface Plasmon Resonance (SPR) results showed that the full length of sPECAM-1 has the strongest binding affinity (KD = 48.4 nM) with sTie2, compared to sPECAM-1-D1-D4 and sPECAM-1-D1-D2. This result is consistent with that in the ELISA. In addition, size-exclusion chromatography demonstrated that sPECAM-1, sTie2, and Ang1 can form a ternary complex. CONCLUSION: In this study, we determined that sPECAM-1 binds to sTie2 in a pH and sodium-dependent manner. The full length of sPECAM-1 has the strongest binding affinity, and the D5-D6 domains in sPECAM-1 play a crucial role in the interaction between sPECAM-1 and sTie2.

HIF-1α-dependent regulation of angiogenic factor expression in Müller cells by mechanical stimulation.

Mechanical stress regulates various biological processes in cells, tissues, and organs as well as contributes to the pathogenesis of various diseases. The retina is subjected to mechanical stress imposed by intraocular pressure as well as by retinal hemorrhage and edema. Responses to mechanical stress have been studied in retinal pigment epithelial cells and Müller cells of the retina, with the former cells having been found to undergo a stress-induced increase in the expression of vascular endothelial growth factor (VEGF), which plays a key role in physiological and pathological angiogenesis in the retina. We here examined the effects of stretch stimulation on the expression of angiogenic factors in cultured human Müller cells. Reverse transcription and quantitative PCR analysis revealed that expression of the VEGF-A gene was increased by such stimulation in Müller cells, whereas that of the angiopoietin 1 gene was decreased. An enzyme-linked immunosorbent assay showed that stretch stimulation also increased VEGF secretion from these cells. Expression of the transcription factor HIF-1α (hypoxia-inducible factor-1α) was increased at both mRNA and protein levels by stretch stimulation, and the HIF-1α inhibitor CAY10585 prevented the effects of mechanical stress on VEGF-A gene expression and VEGF secretion. Furthermore, RNA-sequencing analysis showed that the expression of angiogenesis-related pathway genes was upregulated by stretch stimulation. Our results thus suggest that mechanical stress induces VEGF production in Müller cells in a manner dependent on HIF-1α, and that HIF-1α is therefore a potential therapeutic target for conditions such as diabetic retinopathy, age-related macular degeneration, and retinal vein occlusion.

The Role of Angiopoietins in Cardiovascular Outcomes of Kidney Transplant Recipients: An Ancillary Study from the FAVORIT.

INTRODUCTION: Kidney transplant recipients (KTRs) have increased risk of cardiovascular disease (CVD) mortality. We investigated vascular biomarkers, angiopoietin-1, and angiopoietin-2 (angpt-1, -2), in CVD development in KTRs. METHODS: This ancillary study from the FAVORIT evaluates the associations of baseline plasma angpt-1, -2 levels in CVD development (primary outcome) and graft failure (GF) and death (secondary outcomes) in 2000 deceased donor KTRs. We used Cox regression to analyze the association of biomarker quartiles with outcomes. We adjusted for demographic; CVD- and transplant-related variables; medications; urine albumin-to-creatinine ratio; and randomization status. We calculated areas under the curves (AUCs) to predict CVD or death, and GF or death by incorporating biomarkers alongside clinical variables. RESULTS: Participants' median age was 52 IQR [45, 59] years: with 37% women and 73% identifying as white. Median time from transplantation was 3.99 IQR [1.58, 7.93] years and to CVD development was 2.54 IQR [1.11-3.80] years. Quartiles of angpt-1 were not associated with outcomes. Whereas higher levels of angpt-2 (quartile 4) were associated with about 2 times the risk of CVD, GF, and death (aHR 1.85 [1.25-2.73], p < 0.01; 2.24 [1.36-3.70)], p < 0.01; 2.30 [1.48-3.58], p < 0.01, respectively) as compared to quartile 1. Adding angiopoietins to preexisting clinical variables improved prediction of CVD or death (AUC improved from 0.70 to 0.72, p = 0.005) and GF or death (AUC improved from 0.68 to 0.70, p = 0.005). Angpt-2 may partially explain the increased risk of future CVD in KTRs. Further research is needed to assess the utility of using angiopoietins in the clinical care of KTRs. CONCLUSION: Angpt-2 may be a useful prognostic tool for future CVD in KTRs. Combining angiopoietins with clinical markers may tailor follow-up to mitigate CVD risk.

Serum angiopoietin-2/angiopoietin-1 ratio is associated with cardiovascular and all-cause mortality in peritoneal dialysis patients: a prospective cohort study.

INTRODUCTION: Our objective was to examine the factors associated with the serum angiopoietin-2/angiopoietin-1 (Angpt-2/Angpt-1) ratio in peritoneal dialysis (PD) patients and to investigate the association between Angpt-2/Angpt-1 ratio and cardiovascular and all-cause mortality. METHODS: Patients on PD who were prevalent between January 2014 and April 2015 in the center of Renji Hospital were enrolled. At the time of enrollment, serum and dialysate samples were collected to detect biochemical parameters, serum angiopoietin-2 and angiopoietin-1 levels. Patients were dichotomized into two groups according to a median of Angpt-2/Angpt-1 ratio and followed up prospectively until the end of the study. RESULTS: A total of 325 patients were enrolled, including 168 males (51.7%) with a mean age of 56.9 ± 14.2 years and a median PD duration of 32.4 (9.8-55.9) months. Multiple linear regression showed pulse pressure (ß = 0.206, p < .001) and high-sensitivity C-reactive protein (hs-CRP) (ß = 0.149, p = .011) were positively correlated with serum Angpt-2/Angpt-1 ratio, while residual renal function (RRF) (ß= -0.219, p < .001) was negatively correlated with serum Angpt-2/Angpt-1 ratio. Multivariate Cox regression analysis showed the high serum Angpt-2/Angpt-1 ratio was an independent predictor of cardiovascular mortality (hazard ratio (HR)=2.467, 95% confidence interval (CI) 1.243-4.895, p = .010) and all-cause mortality (HR = 1.486, 95%CI 1.038-2.127, p = .031). In further subgroup analysis by gender, a significant association was shown in high Angpt-2/Angpt-1 ratio with all-cause mortality in male (p < .05), but not in female patients (p>.05). CONCLUSIONS: High Angpt-2/Angpt-1 ratio is an independent risk factor for cardiovascular and all-cause mortality in PD patients.

Analysis of Expression of the ANG1, CaSR and FAK Proteins in Uterine Fibroids.

Understanding the molecular factors involved in the development of uterine myomas may result in the use of pharmacological drugs instead of aggressive surgical treatment. ANG1, CaSR, and FAK were examined in myoma and peripheral tissue samples taken from women after myoma surgery and in normal uterine muscle tissue samples taken from the control group. Tests were performed using tissue microarray immunohistochemistry. No statistically significant differences in ANG1 expression between the tissue of the myoma, the periphery, and the normal uterine muscle tissue of the control group were recorded. The CaSR value was reduced in the myoma and peripheral tissue and normal in the group of women without myomas. FAK expression was also lower in the myoma and periphery compared to the healthy uterine myometrium. Calcium supplementation could have an effect on stopping the growth of myomas.

The Angiopoietin-2/Angiopoietin-1 ratio increases early in burn patients and predicts mortality.

BACKGROUND: Angiopoietin-2 (Angpt-2) is involved in the pathogenesis of the capillary leak syndrome in sepsis and has been shown to be associated with worse outcomes in diverse critical illnesses. It is however unclear whether Angpt-2 plays a similar role in severely burned patients during the early phase characterized by massive capillary leakage. Our aim was to analyze the Angiopoietin-2/Angiopoietin-1 ratio (Angpt-2/Angpt-1 ratio) over the first two days in critically ill burn patients and examine its association with survival and further clinical parameters. METHODS: Adult burn patients with a total burn surface area (TBSA) ≥ 20% treated in the burn intensive care unit (ICU) of the University Hospital of Zurich, Switzerland, were included. Serum samples were collected prospectively and serum Angpt-1 and Angpt-2 were measured by enzyme-linked immunosorbent assay (ELISA) over the first two days after burn insult and stratified according to survival status, TBSA and the abbreviated burn severity index (ABSI). Due to hemodilution in the initial resuscitation phase, the Angpt-2/Angpt-1 ratio was normalized to albumin. RESULTS: Fifty-six patients were included with a median age of 51.5 years. Overall mortality was 14.3% (8/56 patients). The total amount of infused crystalloids was 12́902 ml (IQR 9́362-16́770 ml) at 24 h and 18́461 ml (IQR 13́024-23́766 ml) at 48 h. The amount of substituted albumin was 20 g (IQR 10-50 g) at 24 h and 50 g (IQR 20-60 g) at 48 h. The albumin-corrected Angpt-2/Angpt-1 ratios increased over the first 48 h after the burn insult (d0: 0.5 pg*l/ml*g [IQR 0.24 - 0.80 pg*l/ml*g]; d1: 0.83 pg*l/ml*g [IQR 0.29 - 1.98 pg*l/ml*g]; d2: 1.76 pg*l/ml*g [IQR 0.70 - 3.23 pg*l/ml*g]; p < 0.001) and were significantly higher in eventual ICU non-survivors (p = 0.005), in patients with a higher TBSA (p = 0.001) and in patients with a higher ABSI (p = 0.001). CONCLUSIONS: In analogy to the pathological host response in sepsis, the Angpt-2/Angpt-1 ratio steadily increases in the first two days in critically ill burn patients, suggesting a putative involvement in the pathogenesis of capillary leakage in burns. A higher Angpt-2/Angpt-1 ratio is associated with mortality, total burn surface area and burn scores.

Serum Ang-1/Ang-2 ratio may be a promising biomarker for evaluating severity of diabetic retinopathy.

PURPOSE: To investigate the predictive role of serum angiopoietin-1 and angiopoietin-2 (Ang-1/Ang-2) in evaluating the severity of diabetic retinopathy (DR). METHODS: A total of 101 outpatients with type 2 diabetes mellitus (T2DM) were recruited and were further divided into the following five groups: T2DM without DR (non-DR), mild non-proliferative DR (NPDR), moderate NPDR, severe NPDR and proliferative DR (PDR) in accordance with the International Clinical Diabetic Retinopathy Guidelines. Furthermore, 101 serum samples were included in the further analysis using enzyme-linked immunosorbent assays. A receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic value of each index. RESULTS: The expression of Ang-1 in the PDR group was significantly lower than that in the non-DR group, while Ang-2 showed an opposite upward trend (p < 0.05). The Ang-1/Ang-2 ratio of the non-DR group was significantly lower than that of the moderate NPDR, severe NPDR and PDR (p < 0.05, p < 0.01 and p < 0.01, respectively). Differences in the Ang-1/Ang-2 ratio were observed earlier than those in the individual Ang-1 and Ang-2 measurements. The maximal Youden index was 0.512 with a calculated area under the curve (AUC) value of 0.734 (p < 0.01). CONCLUSIONS: The Ang-1/Ang-2 ratio was helpful in assessing the severity of DR and may provide potential clinical benefits as a biomarker and early warning signs for DR diagnosis.

Angiopoietin-1 promotes triple-negative breast cancer cell proliferation by upregulating carboxypeptidase A4.

Angiopoietin-1 (ANG1) is a pro-angiogenic regulator that contributes to the progression of solid tumors by stimulating the proliferation, migration and tube formation of vascular endothelial cells, as well as the renewal and stability of blood vessels. However, the functions and mechanisms of ANG1 in triple-negative breast cancer (TNBC) are unclear. The clinical sample database shows that a higher level of ANG1 in TNBC is associated with poor prognosis compared to non-TNBC. In addition, knockdown of ANG1 inhibits TNBC cell proliferation and induces cell cycle G1 phase arrest and apoptosis. Overexpression of ANG1 promotes tumor growth in nude mice. Mechanistically, ANG1 promotes TNBC by upregulating carboxypeptidase A4 (CPA4) expression. Overall, the ANG1-CPA4 axis can be a therapeutic target for TNBC.

Angiopoietins as Prognostic Markers for Future Kidney Disease and Heart Failure Events after Acute Kidney Injury.

BACKGROUND: The mechanisms underlying long-term sequelae after AKI remain unclear. Vessel instability, an early response to endothelial injury, may reflect a shared mechanism and early trigger for CKD and heart failure. METHODS: To investigate whether plasma angiopoietins, markers of vessel homeostasis, are associated with CKD progression and heart failure admissions after hospitalization in patients with and without AKI, we conducted a prospective cohort study to analyze the balance between angiopoietin-1 (Angpt-1), which maintains vessel stability, and angiopoietin-2 (Angpt-2), which increases vessel destabilization. Three months after discharge, we evaluated the associations between angiopoietins and development of the primary outcomes of CKD progression and heart failure and the secondary outcome of all-cause mortality 3 months after discharge or later. RESULTS: Median age for the 1503 participants was 65.8 years; 746 (50%) had AKI. Compared with the lowest quartile, the highest quartile of the Angpt-1:Angpt-2 ratio was associated with 72% lower risk of CKD progression (adjusted hazard ratio [aHR], 0.28; 95% confidence interval [CI], 0.15 to 0.51), 94% lower risk of heart failure (aHR, 0.06; 95% CI, 0.02 to 0.15), and 82% lower risk of mortality (aHR, 0.18; 95% CI, 0.09 to 0.35) for those with AKI. Among those without AKI, the highest quartile of Angpt-1:Angpt-2 ratio was associated with 71% lower risk of heart failure (aHR, 0.29; 95% CI, 0.12 to 0.69) and 68% less mortality (aHR, 0.32; 95% CI, 0.15 to 0.68). There were no associations with CKD progression. CONCLUSIONS: A higher Angpt-1:Angpt-2 ratio was strongly associated with less CKD progression, heart failure, and mortality in the setting of AKI.

Heating of the neck or elbows alleviates Raynaud's phenomenon but has different effects on different types of patients with systemic sclerosis.

OBJECTIVES: We previously reported that heating of the neck or elbows alleviated Raynaud's phenomenon in patients with systemic sclerosis and upregulated capillary extension factor angiopoietin-1 (Angpt-1) in the fingertips. Here, we investigated which cases responded better to the effect of heating of the neck or elbows. METHODS: The pre- to post-heating change in the visual analogue scale for Raynaud's phenomenon (ΔVAS) was examined for correlation with age, disease duration, autoantibodies, disease types, corticosteroid dose, capillaroscopic nailfold capillary damage, fingertip Angpt-1 concentrations at baseline, and increased rate of Angpt-1 concentration. RESULTS: The ΔVAS for elbow heating correlated positively with the baseline Angpt-1 concentration, whereas the opposite correlation was observed for neck heating. The other items were not significantly correlated with the ΔVAS; however, the ΔVAS for elbow heating tended to be larger in patients with advanced capillary damage, whereas the opposite trend was observed for neck heating. CONCLUSIONS: Elbow and neck heating alleviated Raynaud's phenomenon to a similar extent, but their mechanism was different. Heating the elbows had a greater effect on patients with advanced capillary damage and lower fingertip Angpt-1 concentrations.

Endothelial glycocalyx is damaged in diabetic cardiomyopathy: angiopoietin 1 restores glycocalyx and improves diastolic function in mice.

AIMS/HYPOTHESIS: Diabetic cardiomyopathy (DCM) is a serious and under-recognised complication of diabetes. The first sign is diastolic dysfunction, which progresses to heart failure. The pathophysiology of DCM is incompletely understood but microcirculatory changes are important. Endothelial glycocalyx (eGlx) plays multiple vital roles in the microcirculation, including in the regulation of vascular permeability, and is compromised in diabetes but has not previously been studied in the coronary microcirculation in diabetes. We hypothesised that eGlx damage in the coronary microcirculation contributes to increased microvascular permeability and hence to cardiac dysfunction. METHODS: We investigated eGlx damage and cardiomyopathy in mouse models of type 1 (streptozotocin-induced) and type 2 (db/db) diabetes. Cardiac dysfunction was determined by echocardiography. We obtained eGlx depth and coverage by transmission electron microscopy (TEM) on mouse hearts perfusion-fixed with glutaraldehyde and Alcian Blue. Perivascular oedema was assessed from TEM images by measuring the perivascular space area. Lectin-based fluorescence was developed to study eGlx in paraformaldehyde-fixed mouse and human tissues. The eGlx of human conditionally immortalised coronary microvascular endothelial cells (CMVECs) in culture was removed with eGlx-degrading enzymes before measurement of protein passage across the cell monolayer. The mechanism of eGlx damage in the diabetic heart was investigated by quantitative reverse transcription-PCR array and matrix metalloproteinase (MMP) activity assay. To directly demonstrate that eGlx damage disturbs cardiac function, isolated rat hearts were treated with enzymes in a Langendorff preparation. Angiopoietin 1 (Ang1) is known to restore eGlx and so was used to investigate whether eGlx restoration reverses diastolic dysfunction in mice with type 1 diabetes. RESULTS: In a mouse model of type 1 diabetes, diastolic dysfunction (confirmed by echocardiography) was associated with loss of eGlx from CMVECs and the development of perivascular oedema, suggesting increased microvascular permeability. We confirmed in vitro that eGlx removal increases CMVEC monolayer permeability. We identified increased MMP activity as a potential mechanism of eGlx damage and we observed loss of syndecan 4 consistent with MMP activity. In a mouse model of type 2 diabetes we found a similar loss of eGlx preceding the development of diastolic dysfunction. We used isolated rat hearts to demonstrate that eGlx damage (induced by enzymes) is sufficient to disturb cardiac function. Ang1 restored eGlx and this was associated with reduced perivascular oedema and amelioration of the diastolic dysfunction seen in mice with type 1 diabetes. CONCLUSIONS/INTERPRETATION: The association of CMVEC glycocalyx damage with diastolic dysfunction in two diabetes models suggests that it may play a pathophysiological role and the enzyme studies confirm that eGlx damage is sufficient to impair cardiac function. Ang1 rapidly restores the CMVEC glycocalyx and improves diastolic function. Our work identifies CMVEC glycocalyx damage as a potential contributor to the development of DCM and therefore as a therapeutic target.

Angiogenic and angiostatic factors present in the saliva of malaria patients.

BACKGROUND: Malaria related mortality is associated with significant deregulation of host inflammatory factors such as interferon-inducible protein 10, a member of the CXC or α-subfamily (CXCL10), and host angiogenic factors such as angiopoietin 1 (Ang-1) and angiopoietin 2 (Ang-2). However, detection of these factors in malaria patients requires the drawing of blood, which is invasive and increases the risk of accidental blood-borne infections. There has been an increased interest in the use of saliva as the body fluid of choice for the diagnosis of many infectious diseases including malaria. Here, saliva levels of CXCL10, Ang-1, and Ang-2 previously shown to be predictive of severe malaria in malaria patients in Ghana were assessed in malaria patients. METHODS: This study was conducted in the Shai-Osudoku District Hospital in Dodowa, Accra, Ghana and the study population comprised 119 malaria patients and 94 non-malaria subjects. The non-malaria subjects are healthy community participants with no malaria infection. Plasma and saliva levels of CXCL10, Ang-1 and Ang-2 of the study participants were measured using an enzyme-linked immunoassay. Complete blood counts of each participant were measured with a haematology autoanalyzer. Pearson correlation was used to evaluate the correlation between plasma and saliva levels of each biomarker in malaria patients. A p-value of < 0.05 was considered significant. Box plots of median biomarker concentrations were plotted. SPSS version 14.2 software was used for statistical analysis. RESULTS: The non-malaria subjects had a median age of 29 years compared to 23 years for malaria patients (p = 0.001). Among the malaria patients, there was a strong significant relationship between CXCL10 (R2 = 0.7, p < 0.0001) and Ang-1 (R2 = 0.7, p < 0.0001). Malaria patients had lower saliva levels of Ang-1 (p = 0.009) and higher saliva levels of CXCL10 (p = 0.004) and Ang-2 (p = 0.001) compared to non-malaria subjects. CONCLUSIONS: This study provides the first evidence of elevated levels of CXCL10 and Ang-2 in the saliva of malaria patients. Detection of CXCL10, Ang-1 and Ang-2 in saliva may have a potential application for non-invasive malaria diagnosis.

Connexin 43 mediated the angiogenesis of buyang huanwu decoction via vascular endothelial growth factor and angiopoietin-1 after ischemic stroke.

Buyang Huanwu decoction (BYHWD), a classical prescription for ischemic stroke, has been reported to promote angiogenesis after focal ischemia. However, the mechanisms of the contribution of BYHWD on angiogenesis are still unclear. Connexin 43 (Cx43) played important roles in the functions of neurogliovascular unit. Therefore, the aim of this study was to explore the potential role of Cx43 in angiogenesis of the ischemic brain after BYHWD treatment. Middle cerebral artery occlusion (MCAO) was used to establish the model of focal ischemia. BYHWD was administrated intragastrically twice a day after MCAO with or without Gap26 (a specific Cx43 inhibitor). Western blot, neurological deficits, immunofluorescent staining, and Evans blue dye were used to confirm the role of Cx43 in angiogenesis after BYHWD treatment. The expression levels of total Cx43 and phosphorylated Cx43 were upregulated by BYHWD and peaked at 7 days post MCAO. Inhibition of Cx43 with Gap26 significantly attenuated the protective role of BYHWD in neurological behavior. BYHWD treatment promoted angiogenesis demonstrated by increased microvascular density, upregulated vascular endothelial growth factor (VEGF), and angiopoietin-1 (Ang-1), while inhibition of Cx43 with Gap26 attenuated these effects of BYHWD. In addition, Gap26 inhibited the beneficial effect of BYHWD on blood-brain barrier (BBB) integrity. These results suggested that Cx43 mediated the angiogenesis of BYHWD via VEGF and Ang-1 after focal ischemic stroke.

Prognostic value of tumour tissue ANG-1 expression and Ang-1 concentration in patients with non-small-cell lung cancer.

Tumor cells stimulate local angiogenesis, resulting in their further multiplication and spread. Angiogenesis is a multifaceted process in which angiopoietins parti- cipate. Angiopoietin-1 (Ang-1) through its receptor Tie2 stimulates endothelial cell survival and the maintenance of the endothelial barrier. These phenomena can support tumour growth by promoting angiogenesis. On the other hand, overproduction of Ang-1 triggers endothelium stability and can lead to angiogenesis inhibition. Because of the ambiguous role of Ang-1, we decided to determine its clinical significance in patients with resectable NSCLC. In a group of 47 patients, tumours and the adjacent non-cancerous tissues were assessed for ANG-1 mRNA expression (using Q-RT-PCR analysis) and Ang-1 concentration (by enzyme-linked immunosorbent assay) together with clinical parameters and the five-year survival rate. ANG-1 expression and Ang-1 concentration were higher in tumour-free tissue, showing no differences between histological types of NSCLC, clinical stage or grading and seemed not to determine the five-year survival. ANG-1 expression and Ang-1 concentration in tumour and tumour-free tissues in patients with NSCLC seem not to be useful as factors supporting either diagnostics or prognosis.

Glycation of Tie-2 Inhibits Angiopoietin-1 Signaling Activation and Angiopoietin-1-Induced Angiogenesis.

The impairment of the angiopoietin-1 (Ang-1)/Tie-2 signaling pathway has been thought to play a critical role in diabetic complications. However, the underlying mechanisms remain unclear. The present study aims to investigate the effects of Tie-2 glycation on Ang-1 signaling activation and Ang-1-induced angiogenesis. We identified that Tie-2 was modified by advanced glycation end products (AGEs) in aortae derived from high fat diet (HFD)-fed mice and in methylglyoxal (MGO)-treated human umbilical vein endothelial cells (HUVECs). MGO-induced Tie-2 glycation significantly inhibited Ang-1-evoked Tie-2 and Akt phosphorylation and Ang-1-regulated endothelial cell migration and tube formation, whereas the blockade of AGE formation by aminoguanidine remarkably rescued Ang-1 signaling activation and Ang-1-induced angiogenesis in vitro. Furthermore, MGO treatment markedly increased AGE cross-linking of Tie-2 in cultured aortae ex vivo and MGO-induced Tie-2 glycation also significantly decreased Ang-1-induced vessel outgrow from aortic rings. Collectively, these data suggest that Tie-2 may be modified by AGEs in diabetes mellitus and that Tie-2 glycation inhibits Ang-1 signaling activation and Ang-1-induced angiogenesis. This may provide a novel mechanism for Ang-1/Tie-2 signal dysfunction and angiogenesis failure in diabetic ischaemic diseases.

Proximal heat stress up-regulates angiopoietin-1 in fingers and reduces the severity of Raynaud's phenomenon in systemic sclerosis: a single-centre pilot study.

OBJECTIVES: Raynaud's phenomenon (RP) is a peripheral vascular disorder that frequently occurs in systemic sclerosis (SSc). Although therapeutic heating seems reasonable given that RP is elicited by cold stimuli, the effects of heating are still unclear. We examined the effects of heating applied on various body parts in SSc patients with RP of fingers. METHODS: Fourteen SSc patients heated their neck, elbows, and wrists with disposable heating pads for 1 week each. The visual analogue scale (VAS) for RP during each heating period was compared with that of each 1-week pre-treatment interval. On the day after the expiration of each heating period, their finger temperature, the finger blood flow, and angiogenesis-related factors (vascular endothelial growth factor, endostatin, angiopoietin-1, and angiopoietin-2) obtained from the cubital vein and fingertip were measured. RESULTS: The mean VAS was significantly reduced during the heating of the neck and elbows. Fingertip blood samples showed significantly increased angiopoietin-1 after each of the heating periods and increased endostatin after wrist heating. After the termination of heating, changes in finger temperature or blood flow could not be detected. CONCLUSIONS: Heating the neck or elbows can alleviate RP in SSc. The heat up-regulates angiopoietin-1 in the fingers.

Angiopoietin 1 release from human neutrophils is independent from neutrophil extracellular traps (NETs).

BACKGROUND: Neutrophils induce the synthesis and release of angiopoietin 1 (Ang1), a cytosolic growth factor involved in angiogenesis and capable of inducing several pro-inflammatory activities in neutrophils. Neutrophils also synthesize and release neutrophil extracellular traps (NETs), comprised from decondensed nuclear DNA filaments carrying proteins such as neutrophil elastase (NE), myeloperoxidase (MPO), proteinase 3 (PR3) and calprotectin (S100A8/S100A9), which together, contribute to the innate immune response against pathogens (e.g., bacteria). NETs are involved in various pathological conditions through pro-inflammatory, pro-thrombotic and endothelial dysfunction effects and have recently been found in heart failure (HF) and type 2 diabetes (T2DM) patients. The aim of the present study was to investigate the role of NETs on the synthesis and release of Ang1 by the neutrophils in patients with T2DM and HF with preserved ejection fraction (HFpEF) (stable or acute decompensated; ADHFpEF) with or without T2DM. RESULTS: Our data show that at basal level (PBS) and upon treatment with LPS, levels of NETs are slightly increased in patients suffering from T2DM, HFpEF ± T2DM and ADHF without (w/o) T2DM, whereas this increase was significant in ADHFpEF + T2DM patients compared to healthy control (HC) volunteers and ADHFpEF w/o T2DM. We also observed that treatments with PMA or A23187 increase the synthesis of Ang1 (from 150 to 250%) in HC and this effect is amplified in T2DM and in all cohorts of HF patients. Ang1 is completely released (100%) by neutrophils of all groups and does not bind to NETs as opposed to calprotectin. CONCLUSIONS: Our study suggests that severely ill patients with HFpEF and diabetes synthesize and release a greater abundance of NETs while Ang1 exocytosis is independent of NETs synthesis.

Mapping Angiopoietin1 Expression in the Developing and Adult Brain.

Angiopoietin1 (Angpt1) is a secreted protein that activates the endothelial Tie2 receptor. Angpt1 plays a critical role in cardiac development and vascular remodeling in response to disease or injury and shows cell type-restricted expression in the lung, eye, and hematopoietic system. However, the expression of Angpt1 in the developing and adult brain is not known. Here, we employ Angpt1-GFP knock-in reporter mice and a systematic analysis of multiple single-cell RNA sequencing datasets to map the expression of Angpt1 during brain development and adulthood. In the developing brain, Angpt1 displays specific spatiotemporal patterns, with strong expression in cerebellar GABA interneuron progenitors and, to a lower level, in glial progenitor and astrocyte lineages. In the adult brain, on the other hand, we show that neurons are the main source of Angpt1 in the cerebrum, while in the cerebellum, expression is mostly restricted to astrocytes. Together, our data provide clarity on the cell types that express Angpt1 in the developing and adult brain and can be utilized to guide future studies, examining Angpt1 function in brain development, homeostasis, and pathological conditions.