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Results for “Endothelial activation”

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At least 19 recordsLinked to original sources

PubMed2026

Effects of CPAP on endothelial activation and fibrinolytic balance in coronary artery disease with obstructive sleep apnea: The RICCADSA randomized controlled trial.

BACKGROUND: Obstructive sleep apnea (OSA) promotes endothelial activation and a prothrombotic milieu through intermittent hypoxia, oxidative stress, and systemic inflammation, mechanisms closely linked to atherosclerosis progression. The vascular effects of continuous positive airway pressure (CPAP) therapy in patients with established coronary artery disease (CAD) remain incompletely understood. OBJECTIVE: To evaluate the longitudinal effects of CPAP treatment on endothelial adhesion molecules and fibrinolytic balance in patients with CAD and OSA. METHODS: In this randomized controlled analysis from the RICCADSA trial, 210 revascularized CAD patients with moderate-to-severe OSA were assigned to CPAP (n = 104) or no-CPAP (n = 106) and had available biomarker measurements at baseline and 12 months. Circulating intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and plasminogen activator inhibitor-1 (PAI-1) were assessed. Linear mixed-effects models were used to examine longitudinal changes and time-by-treatment interactions adjusted for cardiometabolic covariates. RESULTS: For ICAM-1, no significant time-by-treatment interaction was observed. For PAI-1, a borderline time-by-treatment interaction suggested a numerically smaller increase in the CPAP group compared with no-CPAP (p = 0.09). CPAP treatment was associated with a significantly greater reduction in VCAM-1 over time compared with no-CPAP (time-by-treatment interaction p = 0.045 in adjusted models). CONCLUSIONS: CPAP treatment was associated with selective modulation of vascular biomarkers in patients with CAD and OSA, characterized by attenuation of endothelial activation reflected by reduced VCAM-1 levels, while fibrinolytic imbalance appeared largely resistant to intervention. These findings support pathway-specific vascular responses to CPAP and provide mechanistic insight into residual atherosclerotic risk in this high-risk population.

Aged↗

PubMed1977

Converting enzyme activity in endothelial cells isolated from pig pulmonary artery and aorta.

Converting enzyme activity was studied in endothelial cells, isolated from pig pulmonary arteries and aorta by exposure to collagenase. The measure was based on the release of His-Leu from Z-Phe-His-Leu was related to the DNA content of the cellular suspension. The same activity was found in the two types of endothelium: 1 nmol His-Leu/mug DNA per 30 min. Subendothelial cells showed a very low activity, amounting to 10% of the value found for the endothelium. The enzyme activity was 2inhibited by the nonapeptide SQ 20881, EDTA, and the lack of Cl- in the same fashion for the two types of endothelium. The presence of another enzyme hydrolyzing His-Leu was detected in both endothelial populations. Isolated fragments of plasma membrane, however, exhibited only converting enzyme activity. It can be concluded that endothelial cells isolated from large vessels of the pulmonary and the systemic circulations have similar properties when dipeptidyl carboxypeptidase activity is measured.

Angiotensin II↗

PubMed1979

Enzyme activities in endothelial cells and smooth muscle cells from swine aorta.

In populations of cultured arterial endothelial and smooth muscle cells grown under the same conditions, we have measured the total activity per cell of 10 enzymes commonly used as "markers" for subcellular organelles: NADH: ferricyanide reductase, NADH:cytochrome c reductase (rotenone insensitive). NADPH:cytochrome c reductase, alpha-glucosidase, 5'-nucleotidase, alkaline phosphodiesterase I, cytochrome oxidase, monoamine oxidase, cathepsin D, and N-acetyl-beta-glucosaminidase. Significant differences between the cell types were found for 7 of the 10 enzymes tested. The total activity of 5'-nucleotidase in cultured smooth muscle cells was 17 times that of cultured endothelial cells. Comparison of the activities in the two cell types freshly collected and in culture showed that the difference in 5'-nucleotidase in cultured cells is due principally to loss of activity from endothelial cells, suggesting that this activity is regulated differently in the two cell types. In both cell types cathepsin D activity rose during culture.

Acetylglucosaminidase↗

PubMed1979

Appearance in confluent vascular endothelial cell monolayers of a specific cell surface protein (CSP-60) not detected in actively growing endothelial cells or in cell types growing in multiple layers.

The formation of a highly organized vascular and corneal endothelial cell monolayer is associated with the appearance of a 60,000-dalton cell surface protein (CSP-60) (30,000 daltons after reduction with dithiothreitol) which is not detectable in rapidly growing endothelial cells and in subconfluent cultures that do not yet exhibit the strict morphology of a confluent monolayer. It is also absent from vascular smooth muscle cells and from endothelial cultures that are maintained in the absence of fibroblast growth factor and grow on top of each other at confluence. After disorganization of cells in a confluent endothelial monolayer by urea, EDTA, or trypsin, CPS-60 is no longer exposed on the cell surface, but it reappears as soon as the cells readopt their characteristic two-dimensional configuration. This reorganization can be achieved in the presence of cycloheximide and despite removal of fibronectin by urea, EDTA, or trypsin. Maximal amounts of fibronectin and no CSP-60 are detected in subconfluent, but not yet organized, endothelial cultures or in endothelial cells that no longer form a monolayer of nonoverlapping cells at confluence. Likewise, cultures of vascular smooth muscle cells contain fibronectin but no CSP-60. These results suggest that CSP-60, rather than fibronectin, could be involved in the adoption of a monolayer configuration by confluent endothelial cells.

Aorta↗

PubMed2026

Targeting super elongation complex-driven RNA polymerase II elongation reduces plaque vulnerability.

Atherosclerotic plaque rupture is a major cause of myocardial infarction and stroke, yet the mechanisms governing plaque stability remain incompletely understood. Endothelial activation can trigger endothelial-to-mesenchymal transition, a program linked to endothelial dysfunction and lesion vulnerability. Here we investigated whether transcriptional pause release and RNA polymerase II elongation constitute an early regulatory layer that promotes endothelial-to-mesenchymal transition and atherosclerosis. Analysis of human plaque single-cell transcriptomics indicated increased expression of super elongation complex components in endothelial cells with a transition signature. In primary human endothelial cell models, pharmacological inhibition of the super elongation complex attenuated the induction of mesenchymal markers. AFF4, pCDK9, and pSMAD2/3 showed physical interaction during endothelial transition. Genome-wide profiling of RNA polymerase II occupancy revealed reduced promoter-proximal pausing during early transition, accompanied by a rapid increase in nascent transcriptional elongation rates. Super elongation complex inhibition restored pausing and suppressed fast-responding transition-associated target genes. In a human cardiac organoid model, inhibition of the super elongation complex prevented EndMT-induced fibrillar collagen deposition and prevented the loss of beating rate. In a hyperlipidemic Pcsk9 gain-of-function mouse model, super elongation complex inhibition administered both prophylactically and therapeutically after established atherosclerosis reduced plaque burden and reduced features of plaque vulnerability. Finally, analysis of 1048 human plaque segments from the Athero-Express biobank showed significant associations between the elongation axis and multiple vulnerability-related plaque traits. Together, these findings identify rapid transcriptional elongation as a mechanistic driver of endothelial plasticity and features of plaque vulnerability and support targeting the elongation machinery as a potential strategy to reduce features of plaque vulnerability in atherosclerotic disease.

Humans↗

PubMed1977

Histogenesis of myeloid metaplasia in the spleen.

Hemopoietic activity in the spleen is caused by the proliferation of the RE cells of the red pulp, lining the sinusoids and the endothelial cells lining the venous channels and their vasa vasora. The RE cells of the marginal zone do not contribute. As the cells involved line blood spaces, and the immature cells are washed into the circulation hemopoiesis appears to be intravascular. Different agents produce different effect: copper sulphate an early proliferation of both the red pulp and venous cells, phenylhydrazine a red pulp proliferation and antiserum a high venous endothelial activity.

Animals↗

PubMed1979

Lymph node pathology in Trypanosoma brucei-infected sheep.

The temporal sequence of morphological changes occurring in the prefemoral lymph nodes of sheep experimentally infected with Trypanosoma brucei was studied at weekly intervals during the course of infection. Histopathological changes started with lymphoid stimulation which was soon overtaken and masked by intense proliferation of reticulo-endothelial cells. Reticulo-endothelial proliferation resulted in macrophage accumulation, some vascular damage and lymph stasis, varying from insidious to extensive. Reticulo-endothelial activity subsequently decreased and there was an upsurge of proliferative activity in lymphoid tissue. Lymphoid stimulation resulted in increased numbers of primary follicles with active germinal centres and produced cells primarily lymphoblast/plasmablast in type. The response appeared to involve blast cells of the germinal centres rather than thymus-dependent paracortical areas. Both reticulo-endothelial and lymphoid components exhibited marked cellular necrosis which increased throughout the course of infection. Intense lymphopoiesis was not correlated with lymphocytosis but was associated with lymphopaenia.

Animals↗

PubMed2026

Proteomic signatures of adipocyte recruitment in breast cancer.

The tumor microenvironment (TME) is increasingly recognized as a dynamic regulator of breast cancer progression, with adipocytes functioning as active contributors rather than passive bystanders. Here, we investigated the proteomic and morphologic reprogramming of breast cancer-associated adipocytes (BrCAAs) in response to triple-negative breast cancer (TNBC). Using conditioned medium from HCC1143 cells, we established an in vitro BrCAA model and performed mass spectrometry-based proteomics. Comparative profiling revealed 256 differentially expressed proteins, enriched for pathways including fatty acid degradation, carbon metabolism, and glycogen turnover, consistent with a metabolic shift from energy storage to energy supply. Gene ontology and protein-protein interaction analyses further identified cytoskeletal remodeling, adhesion dynamics, and secretory pathway activation, supporting BrCAA-driven microenvironmental remodeling. In the MMTV-PyMT mouse model, morphometric analysis demonstrated progressive size reduction and increased contour irregularity of adipocytes adjacent to tumors, correlating with proteomic evidence of metabolic stress. Importantly, BrCAAs localized at tumor interfaces were associated with increased microvessel density and CD105+ endothelial activation compared to desmoplastic zones. Proteomic enrichment highlighted pro-angiogenic remodeling, with validation of basigin (BSG), integrin αV (ITGAV), and 2,4-dienoyl-CoA reductase 1 (DECR1). Collectively, our findings establish BrCAAs as metabolically and structurally reprogrammed stromal components that promote tumor metabolism and localized angiogenesis, representing potential therapeutic targets in aggressive breast cancer.

Female↗

PubMed1977

Corneal thickness after cataract surgery.

An increase in corneal thickness occurs so regularly after cataract surgery as to be considered to be the rule. It reflects the state of endothelial activity and is therefore affected both by the preoperative condition of the endothelium and the degree of surgical manipulation. The question how quickly the endothelium can be expected to recover with consequent disappearance of corneal swelling is still open to discussion. The central corneal thickness of 55 eyes with normal slit-lamp endothelial appearance undergoing cataract surgery was measured preoperatively and on the 3rd, 7th, 14th, 21st, 28th, and 42nd postoperative days. The initial corneal thickness was 0.56 mm. The greatest corneal swelling, found on the third postoperative day, was 16%. Corneal thickness returned to preoperative values in four eyes within 7 days, in 19 eyes within 14 days, in 39 eyes within 21 days, in 50 eyes within 28 days, and in all 55 eyes within 42 days. Corneal swelling, as measured on the third postoperative day, was greatest (19%) when chromic catgut was used, less (13-16%) when black silk 7/0 was used, and least (9%) when virgin silk 8/0 was used.

Aged↗

PubMed1979

Cavernous hemangioma of the superior mediastinum. Report of a case with electron microscopy and computerized tomography.

An unusual case of cavernous hemangioma of the superior mediastinum in a 38-year-old male is presented. Mediastinal hemangiomas occur more often in children and are usually localized in the anterior-superior compartment in all age groups. Slow expansile growth, lack of infiltration of adjacent structures and microscopically mature cellular elements clearly marked the benign nature of the lesion. Vascular mesenchymal tumors in this location must be approached with caution because of the risks of hemorrhage or local infiltration of vital structures. Electron microscopy revealed active endothelial cells, smooth muscle cells, and intercellular matrix components suggestive of smooth muscle cell origin. Computerized tomography delineated the lesion clearly and demonstrated identical densities for the mass and adjacent blood vessels.

Adult↗

PubMed1979

Inhibition of angiotensin converting enzyme activity in cultured endothelial cells by hypoxia.

Endothelial cells in tissue culture degrade bradykinin and convert angiotensin I to angiotensin II. These are both functions of a single dipeptidyl hydrolase, angiotensin converting enzyme. Monolayer cultures were prepared from human, rabbit, pig, and calf vessels. Angiotensin converting enzyme activity was assessed by adding either bradykinin or angiotensin I to the cells in culture flasks, and measuring residual peptide over time by radioimmunoassay. Peptide degradation was inhibited by the specific converting enzyme inhibitor, SQ 20881. The flasks were equilibrated with varying hypoxic gas mixtures: hypoxia rapidly (less than 2 min) decreased enzyme activity and room air restored it as rapidly. The extent to which activity was reduced was a direct function of PO2 (r = 0.93, P less than 0.001), and there was no enzyme activity below a PO2 of 30 mm Hg. Four preparations were studied with respect to decrease in enzyme activity by hypoxia: (a) intact cells in monolayer, (b) sonicated cells, (c) sonicated cells from which converting enzyme was partially dissolved by a detergent, and (d) purified converting enzyme. Hypoxia had progressively less of an inhibiting effect on the enzyme activity of the preparations as the degree of cell integrity decreased. Hypoxia inhibits angiotensin converting enzyme activity in cultured endothelial cells, but the effect of hypoxia is not on the enzyme per se, but appears to be a unique characteristic of the endothelial cell.

Animals↗

PubMed2026

Targeted Nrf2 activation improves vascular endothelial function with aging and prevents vascular dysfunction following disuse in younger and older adults.

Aging and physical inactivity/disuse contribute to cardiovascular disease, which is attributable, in part, to vascular endothelial dysfunction associated with impaired nuclear-factor erythroid 2-related factor 2 (Nrf2) signaling. However, the ability to augment Nrf2 activation and its effects on age- and disuse-related vascular dysfunction in humans remains limited. In a double-blind, randomized, placebo-controlled study design 20 younger adults (8M/12F, age 27 ± 7 y) and 24 older adults (12M/12F, age 67 ± 8 y) were randomized to receive either placebo or PB125 (200 mg/day, Nrf2 activator) across three visits: baseline, 2 weeks of supplementation, and following either 5 days of bed rest (old) or 2 weeks of limb immobilization (young). Brachial and popliteal artery flow-mediated dilation (FMD), passive leg movement-induced (PLM) leg blood flow (LBF) and vascular conductance (LVC) and serum antioxidant status (superoxide dismutase, SOD) were assessed at each timepoint. Compared to placebo, 2 weeks of PB125 increased brachial (PB125: 2.8 ± 1.5 to 3.8 ± 1.3%, p < 0.0001) and popliteal FMD (PB125: 1.5 ± 1.5 to 2.3 ± 1.4%, p = 0.033) in older, but not younger adults (both, p > 0.27). During bed rest, PB125 preserved brachial (3.8 ± 1.3 to 3.6 ± 1.4%, p = 0.543) and popliteal FMD (2.3 ± 1.4 to 2.7 ± 1.4%, p = 0.269), LVC (1.1 ± 0.8 to 1.1 ± 1.5 AUC, p = 0.530) and circulating SOD concentrations (28.3 ± 7.2 to 28.6 ± 8.6 U/mL, p = 0.888) in older adults compared to placebo (all, p < 0.05). Following limb immobilization, PB125 preserved popliteal FMD (4.4 ± 2.8 to 3.4 ± 1.8%, p = 0.302) in younger adults compared to placebo (p < 0.05). These findings demonstrate targeted Nrf2 activation with PB125 improves age-related vascular endothelial dysfunction while preserving vascular function and antioxidant capacity following periods of disuse.

Humans↗

PubMed2019

Increased acetylation of H3K14 in the genomic regions that encode trained immunity enzymes in lysophosphatidylcholine-activated human aortic endothelial cells - Novel qualification markers for chronic disease risk factors and conditional DAMPs.

To test our hypothesis that proatherogenic lysophosphatidylcholine (LPC) upregulates trained immunity pathways (TIPs) in human aortic endothelial cells (HAECs), we conducted an intensive analyses on our RNA-Seq data and histone 3 lysine 14 acetylation (H3K14ac)-CHIP-Seq data, both performed on HAEC treated with LPC. Our analysis revealed that: 1) LPC induces upregulation of three TIPs including glycolysis enzymes (GE), mevalonate enzymes (ME), and acetyl-CoA generating enzymes (ACE); 2) LPC induces upregulation of 29% of 31 histone acetyltransferases, three of which acetylate H3K14; 3) LPC induces H3K14 acetylation (H3K14ac) in the genomic DNA that encodes LPC-induced TIP genes (79%) in comparison to that of in LPC-induced effector genes (43%) including ICAM-1; 4) TIP pathways are significantly different from that of EC activation effectors including adhesion molecule ICAM-1; 5) reactive oxygen species generating enzyme NOX2 deficiency decreases, but antioxidant transcription factor Nrf2 deficiency increases, the expressions of a few TIP genes and EC activation effector genes; and 6) LPC induced TIP genes(81%) favor inter-chromosomal long-range interactions (CLRI, trans-chromatin interaction) while LPC induced effector genes (65%) favor intra-chromosomal CLRIs (cis-chromatin interaction). Our findings demonstrated that proatherogenic lipids upregulate TIPs in HAECs, which are a new category of qualification markers for chronic disease risk factors and conditional DAMPs and potential mechanisms for acute inflammation transition to chronic ones. These novel insights may lead to identifications of new cardiovascular risk factors in upregulating TIPs in cardiovascular cells and novel therapeutic targets for the treatment of metabolic cardiovascular diseases, inflammation, and cancers. (total words: 245).

Acetylation↗

PubMed1979

Mechanism of action of collagenase on the blood-brain barrier permeability. Increase of endothelial cell pinocytotic activity as shown with horse-radish peroxidase as a tracer.

The ultrastructural mechanism of the protease induced blood-brain barrier permeability-increase was studied with horse-radish peroxidase as a tracer. After intravenous injection of collagenase or pronase, a significantly increased number of pinocytotic vesicles was found in brain capillary endothelial cells. alpha-Chymotrypsine did not exert such an action.

Animals↗

PubMed1979

Effect of thrombin on the fibrinolytic activity of cultured bovine endothelial cells.

The vascular endothelium is a rich source of plasminogen activator (PA) and thus of blood vessel-associated fibrinolytic activity. Cultured bovine aortic endothelial cells were employed to determine if components of the coagulation system interact with the endothelium to modify expression of this activity. The addition of thrombin to these cultures led to a rapid decline in intracellular PA activity, with as little as 3 ng/ml, or 0.1 nM thrombin causing a 50% decrease within 30 min. Thrombin inactivated with diisopropylflurophosphate or hirudin did not elicit the response. Although control cultures secreted high levels of PA, no PA activity could be detected in the media surrounding the thrombin-treated cells. This loss of activity did not appear to result from direct inactivation of PA by thrombin. These observations indicate that the fibrinolytic potential of cultured endothelial cells is rapidly suppressed by trace amounts of thrombin. The generation of thrombin at sites of vascular injury may have a similar effect on the endothelium.

Animals↗

PubMed1977

Synthesis of a fibrinolytic activator and inhibitor by endothelial cells.

Vascular endothelial cells derived from rabbit vena cava and maintained in continuous culture exhibited properties characteristic of the intact endothelium. These cells were used as a model for characterizing the fibrinolytic components specified by the endothelium. Endothelial cells in culture digested radiolabeled fibrinogen. Digestion resulted from the synthesis and secretion of a plasminogen activator. Fibrinolysis was not detected when cells were grown in medium lacking plasminogen, indicating the absence of plasminogen-independent fibrinolytic enzymes. Phorbol-myristate-acetate increased extracellular plasminogen activator activity dramatically. This increase was prevented when actinomycin D or cycloheximide was included in the growth medium, indicating that new gene expression was required for it. Intracellular plasminogen activator could not be detected unless the cell extracts were exposed briefly to mildly acidic conditions. Mixing experiments between acid-treated and untreated extracts suggested that the cells contained a potent, acid-labile inhibitor of fibrinolysis. As little as 10 mug of protein from whole cell extracts inhibited both cell and urokinase-mediated fibrinolysis by more than 70%. Cell fractionation studies localized the inhibitor to the cytosol whereas plasminogen activator activity was restricted to the membrane-rich fraction. This membrane fraction did not require acidification for activity, suggesting that the inhibitor had been removed and that acidification did not activate a plasminogen proactivator. These observations demonstrate that regulation of endothelial fibrinolytic activity is far more complex than had been anticipated and raise several uncertainties in regard to detecting the presence of plasminogen activators in cells and tissues.

Animals↗

PubMed1979

Studies on end-stage kidneys. V. Unusual epithelial activity or remarkable endothelial metaplasia. Findings in a dialyzed kidney.

Tubule-like cells were found lining an artery and several arterioles and within the capillaries of infarcted glomeruli in one block of kidney from one of 54 cases of end-stage/dialysis kidneys. Three other blocks showed tubule-like structures within infarcted glomeruli and adjacent arterioles. Squamous metaplasia of remaining tubule epithelium was found in sections from four blocks of the same kidney. In two of these blocks, infarcted glomeruli had capillaries which were occupied by squamous cells. These findings are discussed as examples of metaplasia of the endothelium or alternatively as epithelial growth and invasion. The use of special stains and multiple blocks for this study seem to have been justified. These changes offer further evidence that the end-stage kidney after dialysis has unique alterations.

Adult↗

PubMed1979

The effect of cultured endothelial cells on factor VIII procoagulant activity.

Cultured human umbilical vein endothelial cells produce a protein that has von Willebrand factor activity and forms immunoprecipitates with rabbit antibody to purified plasma factor VIII/von Willebrand factor (FVIII/vWF) protein, but it has no FVIII procoagulant activity. Of the three characteristics of plasma FVIII/vWF protein, only FVIII procoagulant activity is readily destroyed by trace proteases. A previous report from this laboratory demonstrated protease activity in culture medium under conditions that had been used by others to show that endothelial cells do not synthesize protein with FVIII procoagulant activity. However, even if cultured endothelial cells are placed in protease-free culture medium, no FVIII procoagulant activity can be detected, despite an increase in the level of protein with vWF activity from 0 to 0.57 microgram/ml by 48 hr. This observation and the lack of protease activity in medium left in contact with the cells for 48 hr led to the hypothesis that proteases exist on the surface of cultured umbilical vein endothelial cells. Protease activity was quantitated by the hydrolysis of p-nitroaniline from the substrate, N-benzoyl-phenylalanyl-valyl-arginyl-p-nitroanilide and by degradation of the procoagulant activity of added purified plasma FVIII/vWF protein. In the absence of endothelial cells, no protease activity was present in protease-free culture medium whether or not it had previously overlaid cultured cells. This medium did not cause cleavage of p-nitroaniline from the tripeptide substrate, and 83% of added FVIII procoagulant activity remained after 48 hr. When the synthetic tripeptide was incubated in contact with cultured endothelial cells, 7.3 +/- 0.8 X 10(-10) moles of p-nitroaniline/hr was released; moreover, only 47% of the added FVIII procoagulant activity remained after 48 hr. Given this rate of destruction, it can be calculated that sufficient protease activity exists on the surface of cultured endothelial cells to degrade the procoagulant activity of approximately 1.6 microgram FVIII/vWF protein/hr. This degradation rate is 45 times the rate of release of FVIII/vWF protein from cultured endothelial cells when assessed by the generation of protein with vWF activity. Hence, the detection of FVIII procoagulant activity, if in fact synthesized by cultured endothelial cells, will be most difficult.

Cells, Cultured↗