Regular transient limb ischemia improves endothelial function and inhibits endothelial cell apoptosis to prevent atherosclerosis in rabbit

AIMS

Regular transient limb ischemia (RTLI) can prevent atherosclerosis (AS) progression in hypercholesterolemic rabbits. This study aimed to investigate the minimum effective intensity and possible mechanisms of RTLI for preventing atherosclerosis.

METHODS

Eighty rabbits were divided into eight groups: normal (N), high cholesterol (H), three RTLI [three RTLI cycles every other day (R3qod), three RTLI cycles daily (R3qd), and six RTLI cycles daily (R6qd), each cycle of RTLI included 5 min of limb ischemia followed by 5 min limb reperfusion], and three correlated sham RTLI [sham ischemia for 30 min once every other day (S3qod), sham ischemia for 30 min once daily (S3qd), and sham ischemia for 60 min once daily (S6qd)]. Rabbits in group N were kept normally, while the others were fed 1% cholesterol diet for 12 weeks. The RTLI and sham RTLI groups were received RTLI or sham RTLI procedure, respectively. The plaque area in the thoracic aorta was determined by oil red O staining, and quantifying the ratio of plaque area to intimal area (PA/IA). Endothelium-dependent and -independent relaxation were also determined. Endothelial cell were isolated from abdominal aorta of rabbits, and the apoptosis ratio was detected using flow cytometry.

RESULTS

The PA/IA and early apoptotic cell ratio was significantly lower as well as the endothelium-dependent relaxation response was higher in group R6qd than those in groups H and S6qd, while those in the R3qod group was not significantly different from those in groups H and S3qod, as well as those in the R3qd group showed no significant difference compared to those in groups H and S3qd.

CONCLUSIONS

Six cycles of RTLI daily was the optimal effective intensity to prevent AS progression in rabbits. Endothelial function improvement and apoptosis inhibition might contribute to the anti-AS effects.

Caveolin-1 mediates blood-brain barrier permeability, neuroinflammation, and cognitive impairment in SARS-CoV-2 infection

Blood-brain barrier (BBB) permeability can cause neuroinflammation and cognitive impairment. Caveolin-1 (Cav-1) critically regulates BBB permeability, but its influence on the BBB and consequent neurological outcomes in respiratory viral infections is unknown. We used Cav-1-deficient mice with genetically encoded fluorescent endothelial tight junctions to determine how Cav-1 influences BBB permeability, neuroinflammation, and cognitive impairment following respiratory infection with mouse adapted (MA10) SARS-CoV-2 as a model for COVID-19. We found that SARS-CoV-2 infection increased brain endothelial Cav-1 and increased transcellular BBB permeability to albumin, decreased paracellular BBB Claudin-5 tight junctions, and caused T lymphocyte infiltration in the hippocampus, a region important for learning and memory. Concordantly, we observed learning and memory deficits in SARS-CoV-2 infected mice. Importantly, genetic deficiency in Cav-1 attenuated transcellular BBB permeability and paracellular BBB tight junction losses, T lymphocyte infiltration, and gliosis induced by SARS-CoV-2 infection. Moreover, Cav-1 KO mice were protected from the learning and memory deficits caused by SARS-CoV-2 infection. These results establish the contribution of Cav-1 to BBB permeability and behavioral dysfunction induced by SARS-CoV-2 neuroinflammation.

The proteome of the blood-brain barrier in rat and mouse: highly specific identification of proteins on the luminal surface of brain microvessels by in vivo glycocapture

BACKGROUND

The active transport of molecules into the brain from blood is regulated by receptors, transporters, and other cell surface proteins that are present on the luminal surface of endothelial cells at the blood-brain barrier (BBB). However, proteomic profiling of proteins present on the luminal endothelial cell surface of the BBB has proven challenging due to difficulty in labelling these proteins in a way that allows efficient purification of these relatively low abundance cell surface proteins.

METHODS

Here we describe a novel perfusion-based labelling workflow: in vivo glycocapture. This workflow relies on the oxidation of glycans present on the luminal vessel surface via perfusion of a mild oxidizing agent, followed by subsequent isolation of glycoproteins by covalent linkage of their oxidized glycans to hydrazide beads. Mass spectrometry-based identification of the isolated proteins enables high-confidence identification of endothelial cell surface proteins in rats and mice.

RESULTS

Using the developed workflow, 347 proteins were identified from the BBB in rat and 224 proteins in mouse, for a total of 395 proteins in both species combined. These proteins included many proteins with transporter activity (73 proteins), cell adhesion proteins (47 proteins), and transmembrane signal receptors (31 proteins). To identify proteins that are enriched in vessels relative to the entire brain, we established a vessel-enrichment score and showed that proteins with a high vessel-enrichment score are involved in vascular development functions, binding to integrins, and cell adhesion. Using publicly-available single-cell RNAseq data, we show that the proteins identified by in vivo glycocapture were more likely to be detected by scRNAseq in endothelial cells than in any other cell type. Furthermore, nearly 50% of the genes encoding cell-surface proteins that were detected by scRNAseq in endothelial cells were also identified by in vivo glycocapture.

CONCLUSIONS

The proteins identified by in vivo glycocapture in this work represent the most complete and specific profiling of proteins on the luminal BBB surface to date. The identified proteins reflect possible targets for the development of antibodies to improve the crossing of therapeutic proteins into the brain and will contribute to our further understanding of BBB transport mechanisms.

Endothelial cyst of the adrenal gland: A surgical case report

INTRODUCTION AND IMPORTANCE

Advances in medical imaging have led to increased detection of rare adrenal cysts, typically asymptomatic. The article emphasizes their silent nature and the evolving diagnostic methods.

CASE PRESENTATION

Woman underwent successful laparoscopic removal of a 9 cm left adrenal cyst. Histological analysis identified it as an endothelial cyst.

CLINICAL DISCUSSION

Adrenal cysts, mostly unilateral, have diverse histological types. Diagnosis relies on imaging, and surgical intervention is required for symptomatic cases or those exceeding 5 cm. Minimally invasive techniques have improved outcomes.

CONCLUSIONS

Adrenal cysts, generally benign and asymptomatic, pose diagnostic challenges. Surgical intervention is recommended for larger or symptomatic lesions, with advancements in minimally invasive options improving outcomes.

Somatic Loss-of-Function PIK3R1 and Activating Non-hotspot PIK3CA Mutations Associated with Capillary Malformation with Dilated Veins (CMDV)

Common capillary malformations are red vascular skin lesions, most commonly associated with somatic activating GNAQ or GNA11 mutations. We focused on capillary malformations lacking such a mutation to identify previously unreported genetic causes. We used targeted next-generation sequencing on 82 lesions. Bioinformatic analysis allowed the identification of 9 somatic pathogenic variants in PIK3R1 and PIK3CA, encoding for the regulatory and catalytic subunits of phosphoinositide 3-kinase, respectively. Recharacterization of these lesions unraveled a common phenotype: a pale capillary malformation associated with visible dilated veins. Primary endothelial cells from 2 PIK3R1-mutated lesions were isolated, and PI3k-Akt-mTOR and RAS-RAF-MAPK signaling were assessed by western blot. This unveiled an abnormal increase in Akt phosphorylation, effectively reduced by PI3K pathway inhibitors, such as mTOR, Akt, and PIK3CA inhibitors. The effects of mutant PIK3R1 were further studied using zebrafish embryos. Endothelium-specific expression of PIK3R1 mutants resulted in abnormal development of the posterior capillary-venous plexus. In summary, capillary malformation associated with visible dilated veins emerges as a clinical entity associated with somatic pathogenic variants in PIK3R1 or PIK3CA (nonhotspot). Our findings suggest that the activated Akt signaling can be effectively reversed by PI3K pathway inhibitors. In addition, the proposed zebrafish model holds promise as a valuable tool for future drug screening aimed at developing patient-tailored treatments.

Developmental exposure to methylmercury alters GAD67 immunoreactivity and morphology of endothelial cells and capillaries of midbrain and hindbrain regions of adult rat offspring

INTRODUCTION

Methylmercury (MeHg) is an environmental contaminant that is of particular concern in Northern Arctic Canadian populations. Specifically, organic mercury compounds such as MeHg are potent toxicants that affect multiple bodily systems including the nervous system. Developmental exposure to MeHg is a major concern, as the developing fetus and neonate are thought to be especially vulnerable to the toxic effects of MeHg. The objective of this study was to examine developmental exposure to low doses of MeHg and effects upon the adult central nervous system (CNS). The doses of MeHg chosen were scaled to be proportional to the concentrations of MeHg that have been reported in human maternal blood samples in Northern Arctic Canadian populations.

METHOD

Offspring were exposed to MeHg maternally where pregnant Sprague Dawley rats were fed cookies that contained MeHg or vehicle (vehicle corn oil; MeHg 0.02 mg/kg/body weight or 2.0 mg/kg/body weight) daily, throughout gestation (21 days) and lactation (21 days). Offspring were not exposed to MeHg after the lactation period and were euthanized on postnatal day 450. Brains were extracted, fixed, frozen, and sectioned for immunohistochemical analysis. A battery of markers of brain structure and function were selected including neuronal GABAergic enzymatic marker glutamic acid decarboxylase-67 (GAD67), apoptotic/necrotic marker cleaved caspase-3 (CC3), catecholamine marker tyrosine hydroxylase (TH), immune inflammatory marker microglia (Cd11b), endothelial cell marker rat endothelial cell antigen-1 (RECA-1), doublecortin (DCX), Bergmann glia (glial fibrillary acidic protein (GFAP)), and general nucleic acid and cellular stains Hoechst, and cresyl violet, respectively. Oxidative stress marker lipofuscin (autofluorescence) was also assessed. Both male and female offspring were included in analysis. Two-way analysis of variance (ANOVA) was utilized where sex and treatment were considered as between-subject factors (p* <0.05). ImageJ was used to assess immunohistochemical results.

RESULTS

In comparison with controls, adult rat offspring exposed to both doses of MeHg were observed to have (1) increased GAD67 in the cerebellum; (2) decreased lipofuscin in the locus coeruleus; and (3) decreased GAD67 in the anterior CA1 region. Furthermore, in the substantia nigra and periaqueductal gray, adult male offspring consistently had a larger endothelial cell and capillary perimeter in comparison to females. The maternal high dose of MeHg influenced RECA-1 immunoreactivity in both the substantia nigra and periaqueductal gray of adult rat offspring, where the latter neuronal region also showed statistically significant decreases in RECA-1 immunoreactivity at the maternal low dose exposure level. Lastly, males exposed to high doses of MeHg during development exhibited a statistically significant increase in the perimeter of endothelial cells and capillaries (RECA-1) in the cerebellum, in comparison to male controls.

CONCLUSION

Findings suggest that in utero and early postnatal exposure to MeHg at environmentally relevant doses leads to long-lasting and selective changes in the CNS. Exposure to MeHg at low doses may affect GABAergic homeostasis and vascular integrity of the CNS. Such changes may contribute to neurological disturbances in learning, cognition, and memory that have been reported in epidemiological studies.

O-GlcNAc modification of GSDMD attenuates LPS-induced endothelial cells pyroptosis

OBJECTIVE

Increased O-linked β-N-acetylglucosamine (O-GlcNAc) stimulation has been reported to protect against sepsis associated mortality and cardiovascular derangement. Previous studies, including our own research, have indicated that gasdermin-D(GSDMD)-mediated endothelial cells pyroptosis contributes to sepsis-associated endothelial injury. This study explored the functions and mechanisms of O-GlcNAc modification on lipopolysaccharide (LPS)-induced pyroptosis and its effects on the function of GSDMD.

METHODS

A LPS-induced septic mouse model administrated with O-GlcNAcase (OGA) inhibitor thiamet-G (TMG) was used to assess the effects of O-GlcNAcylation on sepsis-associated vascular dysfunction and pyroptosis. We conducted experiments on human umbilical vein endothelial cells (HUVECs) by challenging them with LPS and TMG to investigate the impact of O-GlcNAcylation on endothelial cell pyroptosis and implications of GSDMD. Additionally, we identified potential O-GlcNAcylation sites in GSDMD by utilizing four public O-GlcNAcylation site prediction database, and these sites were ultimately established through gene mutation.

RESULTS

Septic mice with increased O-GlcNAc stimulation exhibited reduced endothelial injury, GSDMD cleavage (a marker of pyroptosis). O-GlcNAc modification of GSDMD mitigates LPS-induced pyroptosis in endothelial cells by preventing its interaction with caspase-11 (a human homologous of caspases-4/5). We also identified GSDMD Serine 338 (S338) as a novel site of O-GlcNAc modification, leading to decreased association with caspases-4 in HEK293T cells.

CONCLUSIONS

Our findings identified a novel post-translational modification of GSDMD and elucidated the O-GlcNAcylation of GSDMD inhibits LPS-induced endothelial injury, suggesting that O-GlcNAc modification-based treatments could serve as potential interventions for sepsis-associated vascular endothelial injury.

Src kinase partially mediates cytokine-induced endothelial dysfunction

OBJECTIVES

Endothelial dysfunction is known to be a key characteristic of preeclampsia (PE) and can contribute to progression of symptoms and injury to multiple organ systems. Delivery is the only treatment for progression of PE, but development of an endothelial-based therapy for PE presents a promising strategy. Growth factors and cytokines are dysregulated in PE and can impact endothelial function, manifesting changes in Ca2+ signaling and interruptions in monolayer barrier function that contribute to symptoms of hypertension, proteinuria, and edema. In this study, we highlight Src kinase as a partial mediator of growth factor and cytokine mediated endothelial dysfunction.

STUDY DESIGN

Fura-2 Ca2+ imaging and Electrical Cell Impedance Sensing (ECIS) assays are performed on growth factor or cytokine exposed human umbilical vein endothelial cells (HUVECs). Inhibitors to MEK/ERK (U0126) or Src (PP2) are used to determine the contribution of kinase signaling pathways.

MAIN OUTCOME MEASURES

Decreases in HUVEC Ca2+ signaling or monolayer resistance measure endothelial dysfunction. Reversal of endothelial dysfunction by kinase inhibitors reveals the respective contibutions of MEK/ERK and Src kinase.

RESULTS

We show that Src inhibition protects Ca2+ signaling responses against insults induced by VEGF165, bFGF, PlGF, TNFα, and IL-1β. Additionally, we show that Src inhibition protects the endothelial monolayer from the full impact of TNFα insult. Further, we find that MEK/ERK inhibition does not offer protection from growth factor-mediated endothelial dysfunction.

CONCLUSIONS

The results of this study suggest cytokine and growth factor-stimulated Src kinase plays a partial role on promoting endothelial dysfunction in HUVECs.

Wip1 regulates wound healing by affecting activities of keratinocytes and endothelial cells through ATM-p53 and mTOR signaling

BACKGROUND

As a p53-regulated gene, Wip1 regulates proliferation, migration, apoptosis, and senescence of several type cells, but its biological functions in keratinocytes and endothelial cells which are involved wound healing are not fully understood. This study aims to reveal the function and underlying mechanism of Wip1 in wound healing using models of transgenic animal, keratinocytes, and endothelial cells.

METHODS

Using Wip1 knockout C57 BL/6 mice, we investigated effect of Wip1 deficiency on wound healing and angiogenesis; And using HaCaT and HUVEC as keratinocytes and endothelial cells, combined using primary keratinocytes from Wip1 knockout mice, we studied the effects of Wip1 knockdown/knockout or overexpression on proliferation, migration, and protein expressions of signaling components in ATM-p53 and mTOR pathway.

RESULTS

Wip1 deficiency in mice impaired the wound repair and endothelial angiogenesis, reduced the thickness of granulation tissue, and decreased the number of Ki67-positive cells and CD31 positive vessels in granulation tissue. Knockdown of Wip1 by shRNAs suppressed the proliferation and migration of HaCaT and HUVEC cells and induced notably apoptosis in the two cells. In western blot, Wip1 knockdown enriched p53 and ATM proteins, while decreased activated AKT, mTOR and activated S6 ribosomal protein (pS6) levels in HaCaT and HUVEC cells. Ectopic expression of Wip1 decreased the p53 and ATM proteins, while increased activated AKT, mTOR and pS6 levels in HaCaT and HUVEC cells. And in primary keratinocytes from mice tail skin, Wip1 knockout increased p53 and ATM, while decreased activated AKT, mTOR and pS6 protein levels.

CONCLUSION

Our study directly supports that Wip1 regulated skin wound healing possibly by affecting bioactivities including proliferation, migration and apoptosis of keratinocytes and endothelial cells at least through by modulating ATM-p53 and mTOR signaling.

Sex-biased TGFβ signalling in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a rare cardiovascular disorder leading to pulmonary hypertension and, often fatal, right heart failure. Sex differences in PAH are evident, which primarily presents with a female predominance and increased male severity. Disturbed signalling of the transforming growth factor-β (TGFβ) family and gene mutations in the bone morphogenetic protein receptor 2 (BMPR2) are risk factors for PAH development, but how sex-specific cues affect the TGFβ family signalling in PAH remains poorly understood. In this review, we aim to explore the sex bias in PAH by examining sex differences in the TGFβ signalling family through mechanistical and translational evidence. Sex hormones including oestrogens, progestogens, and androgens, can determine the expression of receptors (including BMPR2), ligands, and soluble antagonists within the TGFβ family in a tissue-specific manner. Furthermore, sex-related genetic processes, i.e. Y-chromosome expression and X-chromosome inactivation, can influence the TGFβ signalling family at multiple levels. Given the clinical and mechanistical similarities, we expect that the conclusions arising from this review may apply also to hereditary haemorrhagic telangiectasia (HHT), a rare vascular disorder affecting the TGFβ signalling family pathway. In summary, we anticipate that investigating the TGFβ signalling family in a sex-specific manner will contribute to further understand the underlying processes leading to PAH and likely HHT.

Protective Role of Endothelial SIRT1 in Deep Vein Thrombosis and Hypoxia-induced Endothelial Dysfunction Mediated by NF-κB Deacetylation

Venous hypoxia is considered as the major pathogenetic mechanism linking blood flow stagnancy with deep vein thrombosis (DVT). Our previous study showed that activating SIRT1 may attenuate inferior vena cava (IVC) stenosis-induced DVT in rats. This study was aimed to investigate the role of endothelial SIRT1 in DVT and hypoxia-induced endothelial dysfunction as well as the underlying mechanism. Protein profiling of IVCs and blood plasma of DVT rats induced by IVC stenosis was analysed by 4D Label free proteomics analysis. To verify the independent role of SIRT1 in DVT and oxygen-glucose deprivation (OGD)-induced endothelial dysfunction, SIRT1 specific activator SRT1720 and SIRT1 knockdown in both local IVCs and endothelial cells were employed. Moreover, the role of the NF-κB were investigated using NF-κB inhibitor caffeic acid phenethyl ester (CAPE). SRT1720 significantly inhibited thrombus burden, leukocytes infiltration, protein expressions of cell adhesion molecules and chemokines, as well as acetylation level of NF-κB/p65 in wild DVT rats, while these protective effects of SRT1720 were abolished in rats with SIRT1 knockdown in local IVCs. In vitro, SRT1720 protected endothelial cells against OGD-induced dysfunction characterized with enhanced adhesion of monocytes as well as the protein expressions of cell adhesion molecules and chemokines, whereas these protective effects of SRT1720 were vanished by SIRT1 stable knockdown. Furthermore, CAPE attenuated endothelial cell dysfunction and abolished these effects of SIRT1 knockdown. Collectively, these data suggested that endothelial SIRT1 plays an independent role in ameliorating hypoxia-induced endothelial dysfunction and thrombotic inflammation in DVT, and this effect is mediated by NF-κB deacetylation.

A neuropathologic feature of brain aging: multi-lumen vascular profiles

Cerebrovascular pathologies other than frank infarctions are commonly seen in aged brains. Here, we focus on multi-lumen vascular profiles (MVPs), which are characterized by multiple vessel lumens enclosed in a single vascular channel. Little information exists on the prevalence, risk factors, and co-pathologies of MVPs. Therefore, we used samples and data from the University of Kentucky Alzheimer's Disease Research Center (n = 91), the University of Kentucky Pathology Department (n = 31), and the University of Pittsburgh Pathology Department (n = 4) to study MVPs. Age at death was correlated with MVP density in the frontal neocortex, Brodmann Area 9 (r = 0.51; p < 0.0001). Exploratory analyses were performed to evaluate the association between conventional vascular risk factors (e.g., hypertension, diabetes), cardiovascular diseases (e.g., heart attack, arrhythmia), and cerebrovascular disease (e.g., stroke); the only nominal association with MVP density was a self-reported history of brain trauma (Prevalence Ratio = 2.1; 95 CI 1.1-3.9, before correcting for multiple comparisons). No specific associations were detected between neuropathological (e.g., brain arteriolosclerosis) or genetic (e.g., APOE) variables and MVP density. Using a tissue clearing method called SeeDB, we provide 3-dimensional images of MVPs in brain tissue. We conclude that MVPs are an age-related brain pathology and more work is required to identify their clinical-pathological correlation and associated risk factors.

Heterotypic tumor spheroids: a platform for nanomedicine evaluation

Nanomedicine has emerged as a promising therapeutic approach, but its translation to the clinic has been hindered by the lack of cellular models to anticipate how tumor cells will respond to therapy. Three-dimensional (3D) cell culture models are thought to more accurately recapitulate key features of primary tumors than two-dimensional (2D) cultures. Heterotypic 3D tumor spheroids, composed of multiple cell types, have become more popular than homotypic spheroids, which consist of a single cell type, as a superior model for mimicking in vivo tumor heterogeneity and physiology. The stromal interactions demonstrated in heterotypic 3D tumor spheroids can affect various aspects, including response to therapy, cancer progression, nanomedicine penetration, and drug resistance. Accordingly, to design more effective anticancer nanomedicinal therapeutics, not only tumor cells but also stromal cells (e.g., fibroblasts and immune cells) should be considered to create a more physiologically relevant in vivo microenvironment. This review aims to demonstrate current knowledge of heterotypic 3D tumor spheroids in cancer research, to illustrate current advances in utilizing these tumor models as a novel and versatile platform for in vitro evaluation of nanomedicine-based therapeutics in cancer research, and to discuss challenges, guidelines, and future directions in this field.

Noncoding RNAs in atherosclerosis: regulation and therapeutic potential

Atherosclerosis, a chronic disease of arteries, results in high mortality worldwide as the leading cause of cardiovascular disease. The development of clinically relevant atherosclerosis involves the dysfunction of endothelial cells and vascular smooth muscle cells. A large amount of evidence indicates that noncoding RNAs, such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), are involved in various physiological and pathological processes. Recently, noncoding RNAs were identified as key regulators in the development of atherosclerosis, including the dysfunction of endothelial cells, and vascular smooth muscle cells and it is pertinent to understand the potential function of noncoding RNAs in atherosclerosis development. In this review, the latest available research relates to the regulatory role of noncoding RNAs in the progression of atherosclerosis and the therapeutic potential for atherosclerosis is summarized. This review aims to provide a comprehensive overview of the regulatory and interventional roles of ncRNAs in atherosclerosis and to inspire new insights for the prevention and treatment of this disease.

Feasibility and pilot study of passive heat therapy on cardiovascular performance and laboratory values in older adults

BACKGROUND

Chronic heat therapy may have beneficial effects on cardiovascular function. These effects may be more pronounced in older adults. We performed a pilot feasibility study of repeated heat therapy sessions in a hot tub (40.5 °C) in older adults while wearing a noninvasive hemodynamic monitor. As part of the protocol, the volunteers underwent cardiovascular performance testing pre- and post-intervention.

METHODS

Fifteen volunteers > 50 years old underwent 8-10 separate 45-min hot tub session over 14 days in this exploratory and mixed methods trial. The participants had maximal oxygen consumption (VO₂ max) and other cardiovascular data measured via exercise treadmill testing prior to and after all hot tub sessions. The participants also wore noninvasive fingertip volume clamp monitors while immerged in hot water that calculated systemic vascular resistance, heart rate, blood pressure, and cardiac output in order to ascertain the feasibility and utility of this data. Other laboratory studies were obtained pre- and post-intervention. The protocol was determined feasible if the heat therapy and cardiovascular testing was completed by at least 90% (14/15 subjects). Feasibility of the noninvasive monitor was determined by the fidelity of the results. Secondary exploratory outcomes were analyzed for differences to identify if they are acceptable to include in an efficacy trial.

RESULTS

All participants completed the study protocol identifying the feasibility of the protocol. The noninvasive hemodynamic monitors successfully recorded cardiac output, systemic vascular resistance, heart rate, and blood pressure with fidelity based on the analysis of recordings. In the secondary analyses, we found no difference in the pre- to post-intervention measurement of VO₂ max but did find increased exercise duration following hot tub therapy compared with prior to the therapy (571 s versus 551 s).

CONCLUSIONS

The current pilot study protocol is feasible for the purpose of analyzing the effects of heat therapy and cardiovascular performance in older adults while wearing a noninvasive hemodynamic monitor and undergoing treadmill stress testing. Secondary analyses found increased exercise tolerance but no differences in VO₂ max following heat sessions.

DLL4 promotes partial endothelial-to-mesenchymal transition at atherosclerosis-prone regions of arteries

Flowing blood regulates vascular development, homeostasis and disease by generating wall shear stress which has major effects on endothelial cell (EC) physiology. Low oscillatory shear stress (LOSS) induces a form of cell plasticity called endothelial-to-mesenchymal transition (EndMT). This process has divergent effects; in embryos LOSS-induced EndMT drives the development of atrioventricular valves, whereas in adult arteries it is associated with inflammation and atherosclerosis. The Notch ligand DLL4 is essential for LOSS-dependent valve development; here we investigated whether DLL4 is required for responses to LOSS in adult arteries. Analysis of cultured human coronary artery EC revealed that DLL4 regulates the transcriptome to induce markers of EndMT and inflammation under LOSS conditions. Consistently, genetic deletion of Dll4 from murine EC reduced SNAIL (EndMT marker) and VCAM-1 (inflammation marker) at a LOSS region of the murine aorta. We hypothesized that endothelial Dll4 is pro-atherogenic but this analysis was confounded because endothelial Dll4 negatively regulated plasma cholesterol levels in hyperlipidemic mice. We conclude that endothelial DLL4 is required for LOSS-induction of EndMT and inflammation regulators at atheroprone regions of arteries, and is also a regulator of plasma cholesterol.

Aerobically trained older adults show impaired resting, but preserved exercise-induced circulating progenitor cell count, which was not improved by sprint interval training

Older adults exhibit a reduced number and function of CD34 + circulating progenitor cells (CPC), a known risk factor for cardiovascular disease. Exercise promotes the mobilisation of CPCs from bone marrow, so whether ageing per se or physical inactivity in older age reduces CPCs is unknown. Thus, this study examined the effect of age on resting and exercise-induced changes in CPCs in aerobically trained adults and the effect of 8 weeks of sprint interval training (SIT) on resting and exercise-induced CPCs in older adults. Twelve young (22-34 years) and nine older (63-70 years) adults participated in the study. Blood was sampled pre and immediately post a graded exercise test to exhaustion in both groups. Older participants repeated the process after 8 weeks of SIT (3 × 20 s 'all-out' sprints, 2 × a week). Total CPCs (CD34⁺) and endothelial progenitor cells (EPCs: CD34⁺KDR⁺) were determined by flow cytometry. Older adults exhibited lower basal total CD34⁺ CPCs (828 ± 314 vs. 1186 ± 272 cells·mL^-1, p = 0.0149) and CD34⁺KDR⁺ EPCs (177 ± 128 vs. 335 ± 92 cells·mL^-1, p = 0.007) than younger adults. The maximal exercise test increased CPCs in young (CD34⁺: p = 0.004; CD34⁺KDR⁺: p = 0.017) and older adults (CD34⁺: p < 0.001; CD34⁺KDR⁺: p = 0.008), without difference between groups (p = 0.211). SIT did not alter resting or exercise-induced changes in CPCs in the older cohort (p > 0.232). This study suggests age per se does not impair exercise-induced CPC counts, but does lower resting CPC counts.

The effect of rivaroxaban on biomarkers in blood and plasma: a review of preclinical and clinical evidence

Rivaroxaban is a direct, oral factor Xa inhibitor that is used for the prevention and treatment of various thromboembolic disorders. Several preclinical and clinical studies have utilized specific molecules as biomarkers to investigate the potential role of rivaroxaban beyond its anticoagulant activity and across a range of biological processes. The aim of this review is to summarize the existing evidence regarding the use of blood-based biomarkers to characterize the effects of rivaroxaban on coagulation and other pathways, including platelet activation, inflammation and endothelial effects. After a literature search using PubMed, almost 100 preclinical and clinical studies were identified that investigated the effects of rivaroxaban using molecular biomarkers. In agreement with the preclinical data, clinical studies reported a trend for reduction in the blood concentrations of D-dimers, thrombin-antithrombin complex and prothrombin fragment 1 + 2 following treatment with rivaroxaban in both healthy individuals and those with various chronic conditions. Preclinical and also some clinical studies have also reported a potential impact of rivaroxaban on the concentrations of platelet activation biomarkers (von Willebrand factor, P-selectin and thrombomodulin), endothelial activation biomarkers (matrix metalloproteinase-9, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) and inflammation biomarkers (interleukin-6, tumor necrosis factor-α and monocyte chemoattractant protein-1). Based on the results of biomarker studies, molecular biomarkers can be used in addition to traditional coagulation assays to increase the understanding of the anticoagulation effects of rivaroxaban. Moreover, there is preliminary evidence to suggest that rivaroxaban may have an impact on the biological pathways of platelet activation, endothelial activation and inflammation; however, owing to paucity of clinical data to investigate the trends reported in preclinical studies, further investigation is required to clarify these observations.

Endothelial cell expression of mutant Map2k1 causes vascular malformations in mice

Extracranial arteriovenous malformation (AVM) is a congenital vascular anomaly causing disfigurement, bleeding, ulceration, and pain. Most lesions are associated with somatic MAP2K1 activating mutations in endothelial cells (ECs). The purpose of this study was to determine if EC expression of mutant activated MAP2K1 is sufficient to produce vascular malformations in mice. We generated mice with a ROSA26 allele containing a lox-stop-lox gene trap (GT), Map2k1 cDNA with an activating p.K57N missense mutation, an internal ribosomal entry site, and green fluorescent protein cDNA (R26GT-Map2k1-GFP). We expressed mutant MAP2K1 and GFP in ECs of fetal and newborn mice using Tg-Cdh5Cre or Tg-Cdh5CreER alleles. Tg-Cdh5Cre+/-;R26GT-Map2k1-GFP/+ animals that express mutant MAP2K1 in ECs in utero developed diffuse vascular abnormalities and died by embryonic (E) day 16.5. Tg-Cdh5CreER+/-;R26GT-Map2k1-GFP/+ animals in which mutant MAP2K1 expression was induced in ECs by tamoxifen at postnatal (P) day 1 developed vascular malformations in the brain, ear, and intestines by P23. The lesions consisted of abnormal networks of blood vessels containing recombined and non-recombined ECs. In conclusion, expression of MAP2K1 p.K57N is sufficient to cause vascular malformations in mice. This model can be used to study the malformation process and for pre-clinical pharmacologic studies.

Increased Circulating CD62E+ Endothelial Extracellular Vesicles Predict Severity and in- Hospital Mortality of COVID-19 Patients

COVID-19 and infectious diseases have been included in strategic development goals (SDG) of United Nations (UN). Severe form of COVID-19 has been described as an endothelial disease. In order to better evaluate Covid-19 endotheliopathy, we characterized several subsets of circulating endothelial extracellular vesicles (EVs) at hospital admission among a cohort of 60 patients whose severity of COVID-19 was classified at the time of inclusion. Degree of COVID-19 severity was determined upon inclusion and categorized as moderate to severe in 40 patients and critical in 20 patients. We measured citrated plasma EVs expressing endothelial membrane markers. Endothelial EVs were defined as harboring VE-cadherin (CD144+), PECAM-1 (CD31 + CD41-) or E-selectin (CD62E+). An increase in CD62E + EV levels on admission to the hospital was significantly associated with critical disease. Moreover, Kaplan-Meier survival curves for CD62E + EV level showed that level ≥ 88,053 EVs/μL at admission was a significant predictor of in hospital mortality (p = 0.004). Moreover, CD62E + EV level ≥ 88,053 EV/μL was significantly associated with higher in-hospital mortality (OR 6.98, 95% CI 2.1-26.4, p = 0.002) in a univariate logistic regression model, while after adjustment to BMI CD62E + EV level ≥ 88,053 EV/μL was always significantly associated with higher in-hospital mortality (OR 5.1, 95% CI 1.4-20.0, p = 0.01). The present findings highlight the potential interest of detecting EVs expressing E-selectin (CD62) to discriminate Covid-19 patients at the time of hospital admission and identify individuals with higher risk of fatal outcome.

The glycocalyx and calcium dynamics in endothelial cells

The endothelial glycocalyx is a dynamic surface layer composed of proteoglycans, glycoproteins, and glycosaminoglycans with a key role in maintaining endothelial cell homeostasis. Its functions include the regulation of endothelial barrier permeability and stability, the transduction of mechanical forces from the vascular lumen to the vessel walls, serving as a binding site to multiple growth factors and vasoactive agents, and mediating the binding of platelets and the migration of leukocytes during an inflammatory response. Many of these processes are associated with changes in intracellular calcium levels that may occur through mechanisms that alter calcium entry in the endothelium or the release of calcium from the endoplasmic reticulum. Whether the endothelial glycocalyx can regulate calcium dynamics in endothelial cells is unresolved. Interestingly, during cardiovascular disease progression, changes in calcium dynamics are observed in association with the degradation of the glycocalyx and with changes in barrier permeability and vascular reactivity. Herein, we aim to provide a summarized overview of what is known regarding the role of the glycocalyx as a regulator of endothelial barrier and vascular reactivity during homeostatic and pathological conditions and to provide a perspective on how such processes may relate to calcium dynamics in endothelial cells, exploring a possible connection between components of the glycocalyx and calcium-sensitive pathways in the endothelium.

KPNA2 promotes angiogenesis by regulating STAT3 phosphorylation

PURPOSE

Angiogenesis is involved in many pathological and physiological processes and is mainly driven by hypoxia. Karyopherin subunit alpha 2 (KPNA2), a member of the nuclear transport protein family, was recently shown to be induced by hypoxia in various types of tumours, so we aimed to investigate the role and mechanism of KPNA2 in angiogenesis under hypoxia.

MATERIALS AND METHODS

After overexpression or knockdown of KPNA2 in human umbilical vein endothelial cells (HUVEC) by adenovirus vector infection, the tube formation, proliferation and migration of HUVEC under hypoxia were detected by tubule formation assay, 5-ethynyl-2'-deoxyuridine (EdU) staining and Transwell assay, respectively. After overexpression or knockdown of KPNA2 in a murine hindlimb ischemia model by local injection of purified adenovirus vector into the gastrocnemius muscle, blood flow changes were examined with a laser Doppler system. Changes in KPNA2-binding proteins under hypoxia were detected by immunoprecipitation-mass spectrometry (IP-MS) and co-immunoprecipitation (Co-IP). The effect of KPNA2 on signal transducer and activator of transcription 3 (STAT3) was detected by Western blotting and quantitative RT‒PCR.

RESULTS

KPNA2 was upregulated in the HUVEC hypoxia model and murine hindlimb ischemia model. Overexpression of KPNA2 increased the proliferation, migration and tube formation of HUVEC under hypoxia, while knockdown of KPNA2 reduced the proliferation, migration and tube formation of HUVEC. Overexpression of KPNA2 promoted the restoration of blood flow in the murine hindlimb ischemia model, while knockout of KPNA2 inhibited the restoration of blood flow in the murine hindlimb ischemia model. Mechanistically, hypoxia promoted the binding of STAT3 to KPNA2. Overexpression of KPNA2 promoted STAT3 phosphorylation and then upregulated vascular endothelial growth factor (VEGF) and angiopoietin 2(ANGPT2), whereas knockdown of KPNA2 inhibited STAT3 phosphorylation and then downregulated VEGF and ANGPT2.

CONCLUSION

Our study demonstrates that hypoxia promotes the binding of STAT3 to KPNA2 and KPNA2 promotes angiogenesis under hypoxia by promoting the binding of STAT3 and JAK1 and regulating STAT3 phosphorylation.

Non-pharmacological interventions for vascular health and the role of the endothelium

The most common non-pharmacological intervention for both peripheral and cerebral vascular health is regular physical activity (e.g., exercise training), which improves function across a range of exercise intensities and modalities. Numerous non-exercising approaches have also been suggested to improved vascular function, including repeated ischemic preconditioning (IPC); heat therapy such as hot water bathing and sauna; and pneumatic compression. Chronic adaptive responses have been observed across a number of these approaches, yet the precise mechanisms that underlie these effects in humans are not fully understood. Acute increases in blood flow and circulating signalling factors that induce responses in endothelial function are likely to be key moderators driving these adaptations. While the impact on circulating factors and environmental mechanisms for adaptation may vary between approaches, in essence, they all centre around acutely elevating blood flow throughout the circulation and stimulating improved endothelium-dependent vascular function and ultimately vascular health. Here, we review our current understanding of the mechanisms driving endothelial adaptation to repeated exposure to elevated blood flow, and the interplay between this response and changes in circulating factors. In addition, we will consider the limitations in our current knowledge base and how these may be best addressed through the selection of more physiologically relevant experimental models and research. Ultimately, improving our understanding of the unique impact that non-pharmacological interventions have on the vasculature will allow us to develop superior strategies to tackle declining vascular function across the lifespan, prevent avoidable vascular-related disease, and alleviate dependency on drug-based interventions.

Proper Orthogonal Decomposition Analysis Reveals Cell Migration Directionality During Wound Healing

A proper orthogonal decomposition (POD) order reduction method was implemented to reduce the full high dimensional dynamical system associated with a wound healing cell migration assay to a low-dimensional approximation that identified the prevailing cell trajectories. The POD analysis generated POD modes that were representative of the prevalent cell trajectories. The shapes of the POD modes depended on the location of the cells with respect to the wound and exposure to disturbed (DF) or undisturbed (UF) fluid flow where the net flow was in the antegrade direction with a retrograde component or fully antegrade, respectively. For DF and UF, the POD modes of the downstream cells identified trajectories that moved upstream against the flow, while upstream POD modes exhibited sideways cell migrations. In the absence of flow, no major shape differences were observed in the POD modes on either side of the wound. The POD modes also served to reconstruct the cell migration of individual cells. With as few as three modes, the predominant cell migration trajectories were reconstructed, while the level of accuracy increased with the inclusion of more POD modes. The POD order reduction method successfully identified the predominant cell migratory trajectories under static and varying pulsatile fluid flow conditions serving as a first step in the development of artificial intelligence models of cell migration in disease and development.

Non-pharmacological interventions for vascular health and the role of the endothelium

The most common non-pharmacological intervention for both peripheral and cerebral vascular health is regular physical activity (e.g., exercise training), which improves function across a range of exercise intensities and modalities. Numerous non-exercising approaches have also been suggested to improved vascular function, including repeated ischemic preconditioning (IPC); heat therapy such as hot water bathing and sauna; and pneumatic compression. Chronic adaptive responses have been observed across a number of these approaches, yet the precise mechanisms that underlie these effects in humans are not fully understood. Acute increases in blood flow and circulating signalling factors that induce responses in endothelial function are likely to be key moderators driving these adaptations. While the impact on circulating factors and environmental mechanisms for adaptation may vary between approaches, in essence, they all centre around acutely elevating blood flow throughout the circulation and stimulating improved endothelium-dependent vascular function and ultimately vascular health. Here, we review our current understanding of the mechanisms driving endothelial adaptation to repeated exposure to elevated blood flow, and the interplay between this response and changes in circulating factors. In addition, we will consider the limitations in our current knowledge base and how these may be best addressed through the selection of more physiologically relevant experimental models and research. Ultimately, improving our understanding of the unique impact that non-pharmacological interventions have on the vasculature will allow us to develop superior strategies to tackle declining vascular function across the lifespan, prevent avoidable vascular-related disease, and alleviate dependency on drug-based interventions.

7-Methoxyisoflavone suppresses vascular endothelial inflammation by inhibiting the expression of endothelial adhesion molecules

Endothelial cells (ECs) are vital regulators of inflammatory processes, there is the potential for inhibition of EC inflammation to be a therapeutic target in chronic inflammatory diseases. This study aimed to investigate the effect of 7-methoxyisoflavone (7-Mif) on endothelial inflammation. Our results showed that 7-Mif have no cytotoxicity on HUVECs. Pretreatment with 5 μM, 10 μM and 50 μM 7-Mif significantly reduced IL-1β-induced ICAM-1 (28.1% ± 4.1%, 25.9 ± 2.5% and 32.0% ± 3.2%, respectively) and VCAM-1 (48.0% ± 5.6%, 40.1 ± 3.1% and 39.6% ± 3.1%, respectively) mRNA expression. And pretreatment with 10 μM and 50 μM 7-Mif significantly reduced IL-1β-induced ICAM-1 (45.1% ± 4.4% and 33.6 ± 4.4%, respectively) and VCAM-1 (53.0% ± 3.7% and 53.7 ± 5.1%, respectively) protein levels. Furthermore, pretreatment with 50 μM 7-Mif inhibited monocyte-endothelial cell adhesion (50.2% ± 4.2%). Mechanistically, our results showed that 7-Mif reversed IL-1β-induced NF-κB activation and p65 translocation to the nucleus, therefore inhibiting endothelial cell inflammation. In addition, we confirmed that 7-Mif 10 mg/kg and 20 mg/kg reduced LPS-induced ICAM-1 (47.3% ± 1.3% and 39.0% ± 3.2%, respectively) and VCAM-1 (56.5 ± 2.8% and 47.8 ± 4.3%, respectively) expression and attenuated inflammatory injury in mice. In conclusion, we showed the inhibitory effect of 7-Mif on endothelial inflammation by suppressing the expression of endothelial adhesion molecules and monocyte adhesion. Our data illustrated that 7-Mif could positively regulate the process of endothelial inflammation.

Serum Syndecan-1 levels in patients with immunoglobulin A vasculitis in children

OBJECTIVE

The aim of this study was to evaluate the serum Syndecan-1 (SDC-1) levels in patients with immunoglobulin-A vasculitis (IgAV) in children and its relation with gastrointestinal involvements.

METHODS

Sixty-eight children with IgAV and 48 healthy children were enrolled in this cross-sectional study. Clinical and related laboratory data were collected from a computerized hospital database. Serum SDC-1 was collected on admission prior to treatment.

RESULTS

Forty-eight patients fully met the IgAV diagnostic criteria at admission (IgAV group), 20 patients with rash only and diagnosed IgAV during hospitalization (Purpura group). In IgAV group, 30 patients with gastrointestinal involvements (IgAV-GI group) and 18 patients without gastrointestinal involvements (IgAV-NGI group). SDC-1 serum levels were significantly higher in the IgAV group (86.37 ng/mL (IQR 59.16-117.14 ng/mL)) than in the controls (20.37 ng/mL (IQR 15.52-26.45 ng/mL)) and the Purpura group (32.66 ng/mL (IQR 14.87-49.89 ng/mL)). Additionally, SDC-1 (OR = 1.08) was independently associated with IgAV with a cut-off value (sensitivity and specificity) of 66.55 ng/mL (68.8%, 95.0%), and the area under the curve was 0.908. The serum SDC-1 levels of the IgAV-GI group (106.92 ± 50.12 ng/mL) were significantly higher than those in the IgAV-NGI group (67.52 ± 17.59 ng/mL). Logistic regression analysis showed that SDC-1 (OR = 1.03) was independently associated with IgAV-GI with a cut-off value of 89.39 ng/mL.

CONCLUSIONS

SDC-1 serum levels may mirror vascular endothelium injury and mucosal damage in IgAV. Its applicability as a surrogate biomarker in IgAV remains to be determined.

Farnesyl diphosphate synthase regulated endothelial proliferation and autophagy during rat pulmonary arterial hypertension induced by monocrotaline

Background

The proliferation ability and autophagy level of pulmonary artery endothelial cells (PAECs) play an important role in promoting the development of pulmonary artery hypertension (PAH), and there is still no effective treatment for PAH. Farnesyl diphosphate synthase (FDPS) is a key enzyme in the mevalonate pathway. The intermediate metabolites of this pathway are closely related to the activity of autophagy-associated small G proteins, including Ras-related C3 botulinum toxin substrate 1 (Rac1). Studies have shown that the mevalonate pathway affects the activation levels of different small G proteins, autophagy signaling pathways, vascular endothelial function, and so on. However, the exact relationship between them is still unclear in PAH.

Method

In vitro, western blotting and mRFP-GFP-LC3 puncta formation assays were used to observe the expression of FDPS and the level of autophagy in PAECs treated with monocrotaline pyrrole (MCTP). In addition, cell proliferation and migration assays were used to assess the effect of FDPS on endothelial function, and Rac1 activity assays were used to evaluate the effect of Rac1 activation on PAEC autophagy via the PI3K/AKT/mTOR signaling pathway. In vivo, the right heart catheterization method, hematoxylin and eosin (H&E) staining and western blotting were used to determine the effect of FDPS on PAEC autophagy and monocrotaline (MCT)-induced PAH.

Results

We show that the expression of FDPS is increased in the PAH module in vitro and in vivo, concomitant with the induction of autophagy and the activation of Rac1. Our data demonstrate that inhibition of FDPS ameliorates endothelial function and decreases MCT-induced autophagy levels. Mechanistically, we found that FDPS promotes autophagy, Rac1 activity and endothelial disfunction through the PI3K/AKT/mTOR signaling pathway.

Conclusion

Our study suggests that FDPS contributes to active small G protein-induced autophagy during MCT-induced PAH, which may serve as a potential therapeutic target against PAH.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10020-022-00511-7.

A closer look at endothelial injury-induced platelet hyperactivity and the use of aspirin in the treatment of COVID infection

In this commentary, we make a case that the mechanism of COVID pathogenesis is related to virus-induced endothelial injury resulting in platelet activation and the formation of microthrombi both systemically and in cardiac and pulmnonary circulation which result in major causes of COVID morbidity and mortality. Aspirin by virtue of its irreversible inhibition of platelet COX-1, should reverse these platelet-induced pathogenic changes associated with COVID infection for the 6-9 day lifetime of the platelet. We also cite recent findings of a retrospective analysis that supports the use of low-dose (81 mg) aspirin to treat the symptoms associated with the early stages of COVID infection.

Angiogenesis in adipose tissue and obesity

While most tissues exhibit their greatest growth during development, adipose tissue is capable of additional massive expansion in adults. Adipose tissue expandability is advantageous when temporarily storing fuel for use during fasting, but becomes pathological upon continuous food intake, leading to obesity and its many comorbidities. The dense vasculature of adipose tissue provides necessary oxygen and nutrients, and supports delivery of fuel to and from adipocytes under fed or fasting conditions. Moreover, the vasculature of adipose tissue comprises a major niche for multipotent progenitor cells, which give rise to new adipocytes and are necessary for tissue repair. Given the multiple, pivotal roles of the adipose tissue vasculature, impairments in angiogenic capacity may underlie obesity-associated diseases such as diabetes and cardiometabolic disease. Exciting new studies on the single-cell and single-nuclei composition of adipose tissues in mouse and humans are providing new insights into mechanisms of adipose tissue angiogenesis. Moreover, new modes of intercellular communication involving micro vesicle and exosome transfer of proteins, nucleic acids and organelles are also being recognized to play key roles. This review focuses on new insights on the cellular and signaling mechanisms underlying adipose tissue angiogenesis, and on their impact on obesity and its pathophysiological consequences.

How peritoneal dialysis transforms the peritoneum and vasculature in children with chronic kidney disease-what can we learn for future treatment?

Children with chronic kidney disease (CKD) suffer from inflammation and reactive metabolite-induced stress, which massively accelerates tissue and vascular aging. Peritoneal dialysis (PD) is the preferred dialysis mode in children, but currently used PD fluids contain far supraphysiological glucose concentrations for fluid and toxin removal and glucose degradation products (GDP). While the peritoneal membrane of children with CKD G5 exhibits only minor alterations, PD fluids trigger numerous molecular cascades resulting in major peritoneal membrane inflammation, hypervascularization, and fibrosis, with distinct molecular and morphological patterns depending on the GDP content of the PD fluid used. PD further aggravates systemic vascular disease. The systemic vascular aging process is particularly pronounced when PD fluids with high GDP concentrations are used. GDP induce endothelial junction disintegration, apoptosis, fibrosis, and intima thickening. This review gives an overview on the molecular mechanisms of peritoneal and vascular transformation and strategies to improve peritoneal and vascular health in patients on PD.

Trafficking in blood vessel development

Blood vessels demonstrate a multitude of complex signaling programs that work in concert to produce functional vasculature networks during development. A known, but less widely studied, area of endothelial cell regulation is vesicular trafficking, also termed sorting. After moving through the Golgi apparatus, proteins are shuttled to organelles, plugged into membranes, recycled, or degraded depending on the internal and extrinsic cues. A snapshot of these protein-sorting systems can be viewed as a trafficking signature that is not only unique to endothelial tissue, but critically important for blood vessel form and function. In this review, we will cover how vesicular trafficking impacts various aspects of angiogenesis, such as sprouting, lumen formation, vessel stabilization, and secretion, emphasizing the role of Rab GTPase family members and their various effectors.

The consequence of endothelial remodelling on the blood spinal cord barrier and nociception

Nociception is a fundamental acute protective mechanism that prevents harm to an organism. Understanding the integral processes that control nociceptive processing are fundamental to our appreciation of which cellular and molecular features underlie this process. There is an extensive understanding of how sensory neurons interpret differing sensory modalities and intensities. However, it is widely appreciated that the sensory neurons do not act alone. These work in harmony with inflammatory and vascular systems to modulate pain perception. The spinal cord has an extensive interaction with the capillary network in the form of a blood spinal cord barrier to ensure homeostatic control of the spinal cord neuron milieu. However, there is an extensive appreciation that disturbances in the blood spinal cord barrier contribute to the onset of chronic pain. Enhanced vascular permeability and impaired blood perfusion have both been highlighted as contributors to chronic pain manifestation. Here, we discuss the evidence that demonstrates alterations in the blood spinal cord barrier influences nociceptive processing and perception of pain.

SETD8 cooperates with MZF1 to participate in hyperglycemia-induced endothelial inflammation via elevation of WNT5A levels in diabetic nephropathy

Objective

Diabetic nephropathy (DN) is regarded as the main vascular complication of diabetes mellitus, directly affecting the outcome of diabetic patients. Inflammatory factors were reported to participate in the progress of DN. Wingless-type family member 5 (WNT5A), myeloid zinc finger 1 (MZF1), and lysine methyltransferase 8 (SETD8) have also been reported to elevate inflammatory factor levels and activate the nuclear factor kappa B (NF-κB) pathway to induce endothelial dysfunction. In the current study, it was assumed that MZF1 associates with SETD8 to regulate WNT5A transcription, thus resulting in hyperglycemia-induced glomerular endothelial inflammation in DN.

Methods

The present study recruited 25 diagnosed DN patients (type 2 diabetes) and 25 control participants (nondiabetic renal cancer patients with normal renal function, stage I–II) consecutively. Moreover, a DN rat and cellular model was constructed in the present study. Immunohistochemistry, Western blot, and quantitative polymerase chain reaction (qPCR) were implemented to determine protein and messenger RNA (mRNA) levels. Coimmunoprecipitation (CoIP) and immunofluorescence were implemented in human glomerular endothelial cells (HGECs). Chromatin immunoprecipitation assays and dual luciferase assays were implemented to determine transcriptional activity.

Results

The results of this study indicated that levels of WNT5A expression, p65 phosphorylation (p-p65), and inflammatory factors were all elevated in DN patients and rats. In vitro, levels of p-p65 and inflammatory factors increased along with the increase of WNT5A expression in hyperglycemic HGECs. Moreover, high glucose increased MZF1 expression and decreased SETD8 expression. MZF1 and SETD8 inhibit each other under the stimulus of high glucose, but cooperate to regulate WNT5A expression, thus influencing p-p65 and endothelial inflammatory factors levels. Overexpression of MZF1 and silencing of SETD8 induced endothelial p-p65 and inflammatory factors levels, which can be reversed by si-WNT5A. Mechanistic research indicated that MZF1, SETD8, and its downstream target histone H4 lysine 20 methylation (H4K20me1) all occupied the WNT5A promoter region. sh-SETD8 expanded the enrichment of MZF1 on WNT5A promoter. Our in vivo study proved that SETD8 overexpression inhibited levels of WNT5A, p-p65 expression, and inflammatory factors in DN rats.

Conclusions

MZF1 links with SETD8 to regulate WNT5A expression in HGECs, thus elevating levels of hyperglycemia-mediated inflammatory factors in glomerular endothelium of DN patients and rats.

Trial registration ChiCTR, ChiCTR2000029425. 2020/1/31, http://www.chictr.org.cn/showproj.aspx?proj=48548

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00328-6.

Anatomy and development of the pectoral fin vascular network in the zebrafish

The pectoral fins of teleost fish are analogous structures to human forelimbs, and the developmental mechanisms directing their initial growth and patterning are conserved between fish and tetrapods. The forelimb vasculature is crucial for limb function, and it appears to play important roles during development by promoting development of other limb structures, but the steps leading to its formation are poorly understood. In this study, we use high-resolution imaging to document the stepwise assembly of the zebrafish pectoral fin vasculature. We show that fin vascular network formation is a stereotyped, choreographed process that begins with the growth of an initial vascular loop around the pectoral fin. This loop connects to the dorsal aorta to initiate pectoral vascular circulation. Pectoral fin vascular development continues with concurrent formation of three elaborate vascular plexuses, one in the distal fin that develops into the fin-ray vasculature and two near the base of the fin in association with the developing fin musculature. Our findings detail a complex, yet highly choreographed, series of steps involved in the development of a complete, functional, organ-specific vascular network.

Quantifying Vascular Remodeling in the Mouse Spinal Cord

The spinal cord, a compartment of the central nervous system, is made up of a number of architecturally distinct neural centers that influence an array of neurophysiological systems. The primary role of the spinal cord is the modulation of sensory and motor function by acting as a relay station between the periphery and the brain. Inherently these are considered as neural networks, however the functional dynamics of these tissues consist of a heterogenic population of cell types, all working in harmony to maintain physiological function. Part of this cellular diversity comprises of the vascular network that delivers essential nutrients and oxygen to the spinal cord tissue, whilst also protecting it from potentially tissue damaging substances such as foreign entities including toxic pharmacological agents or pathogens. The viability of the spinal cord is dependent upon the harmonious balance between opposing angiogenic processes; vascular remodeling and vascular regression, tipping the balance to either side contributes to neurodegeneration. Exploring vascular remodeling in the central nervous system requires consideration of the anatomical landscape of the spinal cord and the dynamic nature of the microvasculature. Utilizing immunofluorescent staining and 3D image rendering analysis of the endothelium and mural cell population allows for investigation of cellular as well as molecular mediation of vascular remodeling in the spinal cord. This method can be utilized in a range of rodent models (utilizing pharmacological, disease models, transgenic and/or viral approaches) offering extensive appreciation of the blood-spinal cord barrier.

Endothelial-Dependent Responses Correlate with Pediatric SOFA Scores During Severe Sepsis and Septic Shock

Sepsis is an exaggerated host response to an infectious challenge that is associated with significant alterations in vasomotor tone. We hypothesized that the endothelial dysfunction observed during severe sepsis and septic shock would correlate with the degree of organ failure as determined by the pediatric Sequential Organ Failure Assessment (pSOFA) score. Utilizing laser Doppler perfusion monitoring coupled with iontophoresis, we found that endothelium-dependent vascular reactivity to acetylcholine (ACh) stimulation significantly correlated with both total pSOFA scores and, more specifically, cardiovascular (CV) pSOFA scores. Alternatively, endothelium-independent vascular reactivity using sodium nitroprusside (SNP) did not demonstrate a significant relationship with pSOFA scores. These data suggest that endothelial-mediated vasculopathy may be a key driver of organ dysfunction during episodes of pediatric sepsis.

Endothelial Cell Tube Formation Assay: An In Vitro Model for Angiogenesis

Endothelial cell tube formation assay is one of the most widely used and reliable methods for studying in vitro angiogenesis. Endothelial cells plated over a basement membrane extract and subjected to angiogenic factors in conditioned medium, form a rapid and quantifiable tube network within hours. Tube formation is sustained for 18-24 h, after which time apoptosis occurs and tube networks disintegrate. The tube network can be imaged using a phase contrast microscope, or upon Calcein-AM treatment, a fluorescence/confocal microscope. This assay has several advantages, namely: ease of set up, the ability to test numerous angiogenic/anti-angiogenic factors simultaneously, quick network formation, ability to view live or fixed tube networks, and quantifiability. To ensure successful results and limit variability, proper selection of basement membrane extracts and endothelial cells is necessary, and conditions must be optimized. In summary, this assay is a useful method for screening potential angiogenic/anti-angiogenic factors as well as identifying critical mechanisms and signaling pathways underlying angiogenic-related pathologies.

Chip-Based Assay of Adhesion of Plasmodium falciparum-Infected Erythrocytes to Cells Under Flow

Unique to Plasmodium falciparum malaria parasites, the mature asexual stages of the life cycle are absent from the peripheral blood stream. Using syringe pumps and commercially available microslides, it is possible to mimic the blood flow, and investigate the interactions of erythrocytes infected by well-defined P. falciparum isolates for their ability to bind to various tissue receptors under physiological flow conditions. This chapter outlines the techniques needed to investigate how parasites bind to endothelial cells under physiological sheer stress conditions.

Why is endothelial resilience key to maintain cardiac health?

Myocardial injury as induced by myocardial infarction results in tissue ischemia, which critically incepts cardiomyocyte death. Endothelial cells play a crucial role in restoring oxygen and nutrient supply to the heart. Latest advances in single-cell multi-omics, together with genetic lineage tracing, reveal a transcriptional and phenotypical adaptation to the injured microenvironment, which includes alterations in metabolic, mesenchymal, hematopoietic and pro-inflammatory signatures. The extent of transition in mesenchymal or hematopoietic cell lineages is still debated, but it is clear that several of the adaptive phenotypical changes are transient and endothelial cells revert back to a naïve cell state after resolution of injury responses. This resilience of endothelial cells to acute stress responses is important for preventing chronic dysfunction. Here, we summarize how endothelial cells adjust to injury and how this dynamic response contributes to repair and regeneration. We will highlight intrinsic and microenvironmental factors that contribute to endothelial cell resilience and may be targetable to maintain a functionally active, healthy microcirculation.

Cardiovascular benefits from SGLT2 inhibition in type 2 diabetes mellitus patients is not impaired with phosphate flux related to pharmacotherapy

The beneficial cardiorenal outcomes of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in patients with type 2 diabetes mellitus (T2DM) have been substantiated by multiple clinical trials, resulting in increased interest in the multifarious pathways by which their mechanisms act. The principal effect of SGLT2i (-flozin drugs) can be appreciated in their ability to block the SGLT2 protein within the kidneys, inhibiting glucose reabsorption, and causing an associated osmotic diuresis. This ameliorates plasma glucose elevations and the negative cardiorenal sequelae associated with the latter. These include aberrant mitochondrial metabolism and oxidative stress burden, endothelial cell dysfunction, pernicious neurohormonal activation, and the development of inimical hemodynamics. Positive outcomes within these domains have been validated with SGLT2i administration. However, by modulating the sodium-glucose cotransporter in the proximal tubule (PT), SGLT2i consequently promotes sodium-phosphate cotransporter activity with phosphate retention. Phosphatemia, even at physiologic levels, poses a risk in cardiovascular disease burden, more so in patients with type 2 diabetes mellitus (T2DM). There also exists an association between phosphatemia and renal impairment, the latter hampering cardiovascular function through an array of physiologic roles, such as fluid regulation, hormonal tone, and neuromodulation. Moreover, increased phosphate flux is associated with an associated increase in fibroblast growth factor 23 levels, also detrimental to homeostatic cardiometabolic function. A contemporary commentary concerning this notion unifying cardiovascular outcome trial data with the translational biology of phosphate is scant within the literature. Given the apparent beneficial outcomes associated with SGLT2i administration notwithstanding negative effects of phosphatemia, we discuss in this review the effects of phosphate on the cardiometabolic status in patients with T2DM and cardiorenal disease, as well as the mechanisms by which SGLT2i counteract or overcome them to achieve their net effects. Content drawn to develop this conversation begins with proceedings in the basic sciences and works towards clinical trial data.

Cell penetrating peptides coupled to an endothelial nitric oxide synthase sequence alter endothelial permeability

Delivery of cargo to cells through the use of cell-penetrating peptide (CPP) sequences is an area of rich investigation for targeted therapeutics. Specific to the endothelium, the layer of cells that cover every blood vessel in the body, the loss or alteration of a key enzyme, endothelial nitric oxide synthase (eNOS), is known to contribute to endothelial health during severe, infectious challenge. While the beneficial effects of eNOS are often thought to be mediated through the generation of nitric oxide, some protection is theorized to be through eNOS binding to regulatory pathways via a pentabasic RRKRK motif. We hypothesized that delivery of the eNOS-RRKRK peptide sequence using common CPPs would allow protection against gram-negative lipopolysaccharide (LPS). Combination of the eNOS-RRKRK sequence to the CPP antennapedia (AP) reduced the impact of LPS-induced permeability in cultured human microvascular endothelial cells (HMVECs) as measured by transendothelial electrical resistance (TEER). There was also a modest reduction in cytokine production, however it was observed that AP alone significantly impaired LPS-induced endothelial permeability and cytokine production. In comparison, the CPP trans-activator of transcription (TAT) did not significantly alter endothelial inflammation by itself. When TAT was coupled to the eNOS-RRKRK sequence, protection against LPS-induced permeability was still demonstrated, however cytokine production was not reduced. These data demonstrate that the RRKRK sequence of eNOS can offer some NO-independent protection against LPS-mediated endothelial inflammation, however the degree of protection is highly dependent on the type of CPP utilized for cargo delivery.

MicroRNA let-7f alleviates vascular endothelial cell dysfunction via targeting HMGA2 under oxygen-glucose deprivation and reoxygenation

Stroke is a fatal disease with high disability and mortality and there is no credible treatment for stroke at present. Studies on stroke are extensively developed to explore the underlying mechanisms of ischemic and reperfusion injuries. Herein, we investigated the functions of microRNA let-7f (also termed let-7f-5p) in vascular endothelial cell dysfunction. The bEnd.3 cells were stimulated with oxygen-glucose deprivation and reoxygenation (OGD/R) to mimic cell injury in vitro. CCK-8 assays, flow cytometry and western blot analyses were conducted to examine the viability and apoptosis of bEnd.3 cells. Reverse transcription quantitative polymerase chain reaction analyses were employed to measure RNA expression. Endothelial cell permeability in vitro assay was employed to assess endothelial permeability of bEnd.3 cells, and expression levels of proteins associated with cell apoptosis or blood-brain barrier (BBB) were detected by western blot analyses. Luciferase reporter assay was conducted to explore the combination between let-7f and HMGA2. We found that OGD/R induced injuries on endothelial cells (bEnd.3) by decreasing cell viability and promoting cell apoptosis. Let-7f exhibited low expression in bEnd.3 cells under OGD/R. Let-7f overexpression increased the viability of bEnd.3 cells and inhibited cell apoptosis. In addition, the endothelial permeability of bEnd.3 cells was increased by OGD/R and reversed by let-7f overexpression. The levels of tight junction proteins (ZO-1 and occludin) were downregulated by OGD/R and then reversed by let-7f overexpression. Mechanistically, HMGA2 is a target gene of let-7f and its expression was negatively regulated by let-7f. Rescue assays revealed that HMGA2 overexpression reversed the effects of let-7f overexpression on cell viability, cell apoptosis, endothelial permeability, and BBB function. In conclusion, let-7f alleviates vascular endothelial cell dysfunction by downregulating HMGA2 expression under OGD/R.

Chondroitin Sulfate Promotes Interstitial Cell Activation and Calcification in an In Vitro Model of the Aortic Valve

PURPOSE

Calcific aortic valve disease (CAVD), has been characterized as a cascade of cellular changes leading to leaflet thickening and valvular calcification. In diseased aortic valves, glycosaminoglycans (GAGs) normally found in the valve spongiosa migrate to the collagen I-rich fibrosa layer near calcified nodules. Current treatments for CAVD are limited to valve replacement or drugs tailored to other cardiovascular diseases.

METHODS

Porcine aortic valve interstitial cells and porcine aortic valve endothelial cells were seeded into collagen I hydrogels of varying initial stiffness or initial stiffness-matched collagen I hydrogels containing the glycosaminoglycans chondroitin sulfate (CS), hyaluronic acid (HA), or dermatan sulfate (DS). Assays were performed after 2 weeks in culture to determine cell gene expression, protein expression, protein secretion, and calcification. Multiple regression analyses were performed to determine the importance of initial hydrogel stiffness, GAGs, and the presence of endothelial cells on calcification, both with and without osteogenic medium.

RESULTS

High initial stiffness hydrogels and osteogenic medium promoted calcification, while for DS or HA the presence of endothelial cells prevented calcification. CS was found to increase the expression of pro-calcific genes, increase activated myofibroblast protein expression, induce the secretion of collagen I by activated interstitial cells, and increase calcified nodule formation.

CONCLUSION

This study demonstrates a more complete model of aortic valve disease, including endothelial cells, interstitial cells, and a stiff and disease-like ECM. In vitro models of both healthy and diseased valves can be useful for understanding the mechanisms of CAVD pathogenesis and provide a model for testing novel therapeutics.

Interferon-alpha or -beta facilitates SARS-CoV-2 pulmonary vascular infection by inducing ACE2

Severe viral pneumonia caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is characterized by a hyperinflammatory state typified by elevated circulating pro-inflammatory cytokines, frequently leading to potentially lethal vascular complications including thromboembolism, disseminated intracellular coagulopathy and vasculitis. Though endothelial infection and subsequent endothelial damage have been described in patients with fatal COVID-19, the mechanism by which this occurs remains elusive, particularly given that, under naïve conditions, pulmonary endothelial cells demonstrate minimal cell surface expression of the SARS-CoV-2 binding receptor ACE2. Herein we describe SARS-CoV-2 infection of the pulmonary endothelium in postmortem lung samples from individuals who died of COVID-19, demonstrating both heterogeneous ACE2 expression and endothelial damage. In primary endothelial cell cultures, we show that SARS-CoV-2 infection is dependent on the induction of ACE2 protein expression and that this process is facilitated by type 1 interferon-alpha (IFNα) or -beta(β)—two of the main anti-viral cytokines induced in severe SARS-CoV-2 infection—but not significantly by other cytokines (including interleukin 6 and interferon γ/λ). Our findings suggest that the stereotypical anti-viral interferon response may paradoxically facilitate the propagation of COVID-19 from the respiratory epithelium to the vasculature, raising concerns regarding the use of exogenous IFNα/β in the treatment of patients with COVID-19.

COMP-Ang1: Therapeutic potential of an engineered Angiopoietin-1 variant

The Angiopoietin-1/2 system is an opportune target for therapeutic intervention in a wide range of vascular pathologies, particularly through its association with endothelium. The complex multi-domain structure of native human Angiopoietin-1 has hindered its widespread applicability as a therapeutic agent, prompting the search for alternative approaches to mimicking the Ang1:Tie2 signalling axis; a system with highly complex patterns of regulation involving multiple structurally similar molecules. An engineered variant, Cartilage Oligomeric Matrix Protein - Angiopoietin-1 (COMP-Ang1), has been demonstrated to overcome the limitations of the native molecule and activate the Tie2 pathway with several fold greater potency than Ang1, both in vitro and in vivo. The therapeutic efficacy of COMP-Ang1, at both the vascular and systemic levels, is evident from multiple studies. Beneficial impacts on skeletal muscle regeneration, wound healing and angiogenesis have been reported alongside renoprotective, anti-hypertensive and anti-inflammatory effects. COMP-Ang1 has also demonstrated synergy with other compounds to heighten bone repair, has been leveraged for potential use as a co-therapeutic for enhanced targeted cancer treatment, and has received considerable attention as an anti-leakage agent for microvascular diseases like diabetic retinopathy. This review examines the vascular Angiopoietin:Tie2 signalling mechanism, evaluates the potential therapeutic merits of engineered COMP-Ang1 in both vascular and systemic contexts, and addresses the inherent translational challenges in moving this potential therapeutic from bench-to-bedside.

Circulating extracellular vesicles during pregnancy in women with type 1 diabetes: a secondary analysis of the CONCEPTT trial

BACKGROUND

Extracellular vesicles are membrane vesicles that are released into the extracellular environment and accumulate in the circulation in vascular disease. We aimed to quantify circulating extracellular vesicles in pregnant women with type 1 diabetes and to examine associations between extracellular vesicle levels, continuous glucose measures, and pregnancy outcomes.

METHODS

We used plasma samples from the Continuous Glucose Monitoring in Women with Type 1 Diabetes in Pregnancy Trial study and quantified circulating extracellular vesicles by flow cytometry (n = 163). Relationships with clinical variables were assessed by repeated measures correlation. Logistic regression was used to assess associations between elevated extracellular vesicle levels and pregnancy outcomes.

RESULTS

Platelet extracellular vesicle levels were inversely associated with glucose time above range and glycaemic variability measures (P < 0.05). A weak positive association was observed between endothelial extracellular vesicles and mean amplitude of glycemic excursion (P < 0.05). In a univariate logistic regression model, high baseline endothelial extracellular vesicles was associated with increased risk of neonatal intensive care unit (NICU) admission (OR: 2.06, 1.03-4.10), and respiratory distress requiring ventilation (OR: 4.98, 1.04-23.92). After adjusting for HbA1c and blood pressure the relationship for NICU admission persisted and an association with hyperbilirubinemia was seen (OR: 2.56, 1.10-5.94). Elevated platelet extracellular vesicles were associated with an increased risk of NICU admission (OR: 2.18, 1.04-4.57), and hyperbilirubinemia (OR: 2.61, 1.11-6.12) after adjusting for HbA1c and blood pressure.

CONCLUSIONS

High levels of extracellular vesicles in early pregnancy were associated with adverse neonatal outcomes. Assessment of extracellular vesicles may represent a novel approach to personalized care in type 1 diabetes pregnancy.

Considerations When Developing Blood-Brain Barrier Crossing Drug Delivery Technology

Efficient therapeutic transport across the neurovasculature remains a challenge for developing medicine to treat central nervous system (CNS) disorders (Bell and Ehlers, Neuron 81:1-3, 2014). This chapter is meant to provide some insight and key considerations for developing and evaluating various technologies and approaches to CNS drug delivery. First, a brief review of various biological barriers, including the immune system, cellular and protein components of the blood-brain barrier (BBB), and clearance mechanisms in peripheral organs is provided. Next, a few examples and learnings from existing BBB-crossing modalities will be reviewed. Insight from "BBBomic" databases and thoughts on basic requirements for successful in vivo validation studies are discussed. Finally, an additional engineering barrier, namely manufacturing and product scalability, is highlighted as it relates to clinical translation and feasibility for developing BBB-crossing delivery technologies. A goal of this chapter is to provide an overview of the many barriers to the successful delivery of medicines into the brain. An emphasis will be placed on biotherapeutic and gene therapy applications for the treatment of neurological and neurodegenerative disorders.

Lessons learned from experimental models of cerebrovascular aneurysms to improve endocardial device occlusion of the left atrial appendage

In patients with atrial fibrillation, left atrial appendage (LAA) occlusion devices represent an alternative to anticoagulation but are associated with residual peridevice leaks (PDLs) and device-related thrombi (DRT). Similarly, cerebrovascular aneurysms can be treated with coil embolization, but pericoil leaks represent a significant limitation. In experimental models of cerebrovascular aneurysms, endothelial denudation achieved independently with (1) embolization with radioactive coils, (2) mechanical removal of the endothelium, or (3) radiofrequency ablation was dramatically effective in preventing or eliminating pericoil leaks.

Anatomical, physiological, and blood flow similarities exist between the LAA and saccular aneurysms. Concepts developed in treating aneurysm leaks can be used to treat similar problems in the LAA. Learning from aneurysms, we conceived of a novel technique to denude local endothelium and thus eliminate residual leaks around LAA-occlusion devices. We recently successfully tested this hypothesis in patients with a PDL in a prospective manner in a multicenter study. In this article, we expand on the rationale of the technique developed to close PDLs and potentially also prevent DRTs.