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Aim: Protein disulfide isomerases (PDIs) are involved in platelet aggregation and intravascular thrombosis, but their role in regulating endothelial function is unclear. Here, we characterized the involvement of vascular PDIA1 in angiotensin II (Ang II)‐induced endothelial dysfunction in mice. Methods: Endothelial dysfunction was induced in C57BL/6JCmd male mice via Ang II subcutaneous infusion, and PDIA1 was inhibited with bepristat. Endothelial function was assessed in vivo with magnetic resonance imaging and ex vivo with a myography, while arterial stiffness was measured as pulse wave velocity. Nitric oxide (NO) bioavailability was measured in the aorta (spin‐trapping electron paramagnetic resonance) and plasma (NO2− and NO3− levels). Oxidative stress, eNOS uncoupling (DHE‐based aorta staining), and thrombin activity (thrombin–antithrombin complex; calibrated automated thrombography) were evaluated. Results: The inhibition of PDIA1 by bepristat in Ang II‐treated mice prevented the impairment of NO‐dependent vasodilation in the aorta as evidenced by the response to acetylcholine in vivo, increased systemic NO bioavailability and the aortic NO production, and decreased vascular stiffness. Bepristat's effect on NO‐dependent function was recapitulated ex vivo in Ang II‐induced endothelial dysfunction in isolated aorta. Furthermore, bepristat diminished the Ang II‐induced eNOS uncoupling and overproduction of ROS without affecting thrombin activity. Conclusion: In Ang II‐treated mice, the inhibition of PDIA1 normalized the NO‐ROS balance, prevented endothelial eNOS uncoupling, and, thereby, improved vascular function. These results indicate the importance of vascular PDIA1 in regulating endothelial function, but further studies are needed to elucidate the details of the mechanisms involved. [ABSTRACT FROM AUTHOR]

Aims Endothelial dysfunction (ED) and red blood cell distribution width (RDW) are both prognostic factors in heart failure (HF), but the relationship between them is not clear. In this study, we used a unique mouse model of chronic HF driven by cardiomyocyte-specific overexpression of activated Gαq protein (Tgαq*44 mice) to characterize the relationship between the development of peripheral ED and the occurrence of structural nanomechanical and biochemical changes in red blood cells (RBCs). Methods and results Systemic ED was detected in vivo in 8-month-old Tgαq*44 mice, as evidenced by impaired acetylcholine-induced vasodilation in the aorta and increased endothelial permeability in the brachiocephalic artery. ED in the aorta was associated with impaired nitric oxide (NO) production in the aorta and diminished systemic NO bioavailability. ED in the aorta was also characterized by increased superoxide and eicosanoid production. In 4- to 6-month-old Tgαq*44 mice, RBC size and membrane composition displayed alterations that did not result in significant changes in their nanomechanical and functional properties. However, 8-month-old Tgαq*44 mice presented greatly accentuated structural and size changes and increased RBC stiffness. In 12-month-old Tgαq*44 mice, the erythropathy was featured by severely altered RBC shape and elasticity, increased RDW, impaired RBC deformability, and increased oxidative stress (gluthatione (GSH)/glutathione disulfide (GSSG) ratio). Moreover, RBCs taken from 12-month-old Tgαq*44 mice, but not from 12-month-old FVB mice, coincubated with aortic rings from FVB mice, induced impaired endothelium-dependent vasodilation and this effect was partially reversed by an arginase inhibitor [2(S)-amino-6-boronohexanoic acid]. Conclusion In the Tgαq*44 murine model of HF, systemic ED accelerates erythropathy and, conversely, erythropathy may contribute to ED. These results suggest that erythropathy may be regarded as a marker and a mediator of systemic ED in HF. RBC arginase and possibly other RBC-mediated mechanisms may represent novel therapeutic targets for systemic ED in HF. [ABSTRACT FROM AUTHOR]

While the plasma phylloquinone (PK) concentration is inversely correlated with cardiovascular risk, the involvement of PK in regulating endothelial function has not been directly investigated. Therefore, in this study we assessed the effects of short-term treatment with PK-deficient diets (5-10 weeks) on endothelial function in normolipidemic 14-week-old male C57BL/6JCmd mice and age-matched dyslipidaemic male E3L.CETP mice. Our results show that in normolipidemic mice dietary PK deficiency was associated with a marked reduction of PK levels in the plasma and liver (liquid chromatography-mass spectrometry measurements) and with impaired endothelium-dependent vasodilation assessed in vivo by magnetic resonance imaging (MRI). Dietary PK deficiency-induced endothelial dysfunction was fully reversed by PK supplementation. In dyslipidaemic E3L.CETP mice, dietary PK deficiency exacerbated preexisting endothelial dysfunction. Furthermore, dietary PK deficiency decreased menaquinone-4 (MK-4) levels in the aorta but did not affect blood coagulation (calibrated automated thrombography), microbiota composition (culturing and next-generation sequencing), and gut menaquinone production. In conclusion, our study demonstrated for the first time that sufficient dietary PK intake supports endothelial function in normolipidemic and dyslipidaemic mice indicating nutritional significance of dietary PK in the maintenance of endothelial function in humans., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025. Published by Elsevier Inc.)

Detection of free radicals in tissues is challenging. Most approaches rely on incubating excised sections or homogenates with reagents, typically at supraphysiologic oxygen tensions, to finally detect surrogate, nonspecific end products. In the present work, we explored the potential of using intravenously (i.v.) injected dihydroethidine (DHE) to detect superoxide radical (O 2 ∙- ) abundance in vivo by quantification of the superoxide-specific DHE oxidation product, 2-hydroxyethidium (2-OH-E + ), as well as ethidium (E + ) and DHE in multiple tissues in a murine model of endotoxemia induced by lipopolysaccharide (LPS). LPS was injected intraperitoneally (i.p.), while DHE was delivered via the tail vein one hour before sacrifice. Tissues (kidney, lung, liver, and brain) were harvested and subjected to HPLC/fluorescent analysis of DHE and its monomeric oxidation products. In parallel, electron spin resonance (EPR) spin trapping was used to measure nitric oxide ( ∙ NO) production in the aorta, lung, and liver isolated from the same mice. Endotoxemic inflammation was validated by analysis of plasma biomarkers. The concentration of 2-OH-E + varied in the liver, lung, and kidney; however, the ratios of 2-OH-E + /E + and 2-OH-E + /DHE were increased in the liver and kidney but not in the lung or the brain. An LPS-induced robust level of ∙ NO burst was observed in the liver, whereas the lung demonstrated a moderate yet progressive increase in the rate of ∙ NO production. Interestingly, endothelial dysfunction was observed in the aorta, as evidenced by decreased ∙ NO production 6 hours post-LPS injection that coincided with the inflammatory burden of endotoxemia (e.g. elevated serum amyloid A and prostaglandin E 2 ). Combined, these data demonstrate that systemic delivery of DHE affords the capacity to specifically detect O 2 ∙- production in vivo . Furthermore, the ratio of 2-OH-E + /E + oxidation products in tissues provides a tool for comparative insight into the oxidative environments in various organs. Based on our findings, we demonstrate that the endotoxemic liver is susceptible to both O 2 ∙- -mediated and nonspecific oxidant stress as well as nitrosative stress. Oxidant stress in the lung was detected to a lesser extent, thus underscoring a differential response of liver and lung to endotoxemic injury induced by intraperitoneal LPS injection.

Endothelial dysfunction is recognized as a critical condition in the development of cardiovascular disorders. This multifactorial process involves changes in the biochemical and mechanical properties of endothelial cells leading to disturbed release of vasoprotective mediators. Hypercholesterolemia and increased stiffness of the endothelial cortex are independently shown to result in reduced release of nitric oxide and thus endothelial dysfunction. However, direct evidence linking these parameters to each other is missing. Here, a novel method combining Raman spectroscopy for biochemical analysis and Atomic Force Microscopy (AFM) for analyzing the endothelial nanomechanics was established. Using this dual approach, the same areas of native ex vivo aortas were investigated, either derived from mice with endothelial dysfunction (ApoE/LDLR-/-) or wild type mice. In particular an increased intracellular lipid content and elevated cortical stiffness/elasticity were shown in ApoE/LDLR-/- aortas, demonstrating a direct link between endothelial dysfunction, the biochemical composition and the nanomechanical properties of endothelial cells., (Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.)

It has been repeatedly shown that regular aerobic exercise exerts beneficial effects on incidence and progression of cancer. However, the data regarding effects of exercise on metastatic dissemination remain conflicting. Therefore, in the present study the possible preventive effects of voluntary wheel running on primary tumor growth and metastases formation in the model of spontaneous pulmonary metastasis were analyzed after orthotopic injection of 4T1 breast cancer cells into mammary fat pads of female Balb/C mice. This study identified that in the mice injected with 4T1 breast cancer cells and running on the wheels (4T1 ex) the volume and size of the primary tumor were not affected, but the number of secondary nodules formed in the lungs was significantly increased compared to their sedentary counterparts (4T1 sed). This effect was associated with decreased NO production in the isolated aorta of exercising mice (4T1 ex), suggesting deterioration of endothelial function that was associated with lower platelet count without their overactivation. This was evidenced by comparable selectin P, active GPIIb/IIIa expression, fibrinogen and vWF binding on the platelet surface. In conclusion, voluntary wheel running appeared to impair, rather than improve endothelial function, and to promote, but not decrease metastasis in the murine orthotopic model of metastatic breast cancer. These results call for revising the notion of the persistent beneficial effects of voluntary exercise on breast cancer progression, though further studies are needed to elucidate mechanisms involved in pro-metastatic effects of voluntary exercise., Competing Interests: None.