Search Results (435)

Background/Objectives: The renin–angiotensin–aldosterone (RAA) system is a key regulator of cardiovascular homeostasis. Recent evidence suggests that Angiotensin II (Ang II) can trigger ferroptosis, an iron-dependent form of cell death. We previously demonstrated that periodontitis induces neurovascular dysfunction, and our preliminary observations indicate that this oral inflammatory model is associated with elevated blood pressure. However, the mechanism by which Ang II impaired nitrergic vasodilation and triggered ferroptosis in cerebral arteries remains unclear. This study investigates the functional effects of electrical and chemical nerve stimulation in adult spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Methods: Endothelium-denuded basilar arterial (BA) rings from SHRs and WKYs were used to assess the impact of Ang II on neurogenic relaxation via wire myography. Results: Vascular relaxation responses to nicotine and transmural nerve stimulation (TNS) were significantly diminished in SHRs compared to WKYs. This impairment was reversed by both acute preincubation and chronic treatment with losartan (an AT1 receptor antagonist). In WKY BAs, exogenous Ang II pretreatment inhibited relaxation responses to nicotine, TNS, and isoproterenol. Importantly, this inhibition was effectively reversed by marimastat (MMP inhibitor), catalase (antioxidant), and ferrostatin-1 (ferroptosis inhibitor). Conclusions: Our findings indicate that Ang II induces functional alterations in neurovascular signaling patterns by triggering ferroptosis within nerve terminals. This process leads to a functional imbalance between sympathetic and parasympathetic influences, ultimately impairing neurogenic nitrergic dilation in the BAs of SHRs. These results suggest that targeting Ang II-induced ferroptosis may alleviate the neuroinflammation and cognitive decline associated with hypertension-related cerebrovascular dysfunction. Full article

Background/Objective: Buccal delivery offers a potential route to circumvent gastrointestinal degradation and hepatic first-pass metabolism, but hydrophilic peptides typically exhibit limited mucosal permeation. Nanostructured lipid carriers (NLCs) have been proposed as delivery platforms capable of modulating interfacial interactions and improving mucosal transport. This study aimed to quantitatively evaluate the ex vivo buccal permeation of angiotensin II (Ang II), used as a hydrophilic peptide model, when associated with NLCs compared with free peptide under matched Franz diffusion cell conditions. Methods: Ang II-associated NLCs were prepared by melt emulsification combined with a low-energy injection technique. Particle size, polydispersity index, and zeta potential were determined by dynamic light scattering and laser Doppler electrophoresis. Association efficiency and drug loading were quantified by indirect spectrofluorometric analysis. Ex vivo permeation studies were conducted using porcine buccal mucosa mounted in Franz diffusion cells, and cumulative permeation, steady-state flux, and apparent permeability coefficients were calculated. Results: The NLCs exhibited nanometric size, moderate polydispersity, and association efficiency above 80%, and remained colloidally stable at 4 °C for 28 days. In ex vivo experiments, Ang II-associated NLCs showed measurable cumulative permeation, reaching approximately 9% after 2 h, whereas free Ang II was not detected in the receptor compartment under the tested conditions. Conclusions: This work provides a quantitative ex vivo buccal transport comparison of a hydrophilic peptide model delivered as NLC-associated versus free peptide under matched Franz cell conditions. The findings support further investigation of NLC-based approaches for buccal delivery of vasoactive peptides and provide a rational basis for future in vivo evaluation of mucosal delivery performance and systemic exposure. Full article

In patients, extraintestinal manifestations of inflammatory bowel disease (IBD) are attenuated ventricular contractile function and arrhythmia. To determine the mechanism of IBD-induced changes in ventricular function, we used a mouse model of dextran sodium sulfate (3.5% weight/volume; 7 days)-induced colitis. Changes in cardiac function were quantified in isolated ventricular myocytes (VM) by cell shortening, imaging of [Ca²⁺]_i, reactive oxygen species (ROS), and t-tubular density. During colitis, VMs exhibited attenuated cell-shortening and altered Ca²⁺-handling properties. A prolonged Ca²⁺ transient (CaT) rise time correlated with an increased coefficient of variation in the subcellular Ca²⁺ release and an attenuated t-tubular density. T-tubular loss was accompanied by increased ROS production, calpain-2 (CAPN2) expression, junctophilin-2 (JPH-2) cleavage, and autophagy. Inhibition of Angiotensin-converting enzyme during colitis (Perindopril: 3 mg/kg/day) prevented the increase in CAPN2, ROS production, autophagy, and t-tubular remodeling. It failed, however, to restore full length JPH-2. We conclude that, during IBD, the angiotensin II (AngII)-induced loss of t-tubular integrity and altered cellular Ca²⁺ handling can be prevented by suppression of the AngII-dependent increase in CAPN2 and autophagy and thus suppression of AngII signaling might benefit IBD patients with cardiac manifestations of the disease. Full article

Background: Abdominal aortic aneurysm (AAA) is a vascular disease with a high mortality rate upon rupture (85–90%). Surgical repair remains the most effective intervention, whereas pharmacological treatments to prevent aneurysm expansion or rupture are limited. Vascular smooth muscle cells (VSMCs) play a crucial role in AAA pathogenesis, and metabolic dysregulation is increasingly recognized as a contributor to disease progression. This study investigated metabolic changes in VSMCs and their association with AAA pathology using untargeted metabolomics. Methods: Angiotensin II (Ang II) was used to stimulate rat VSMCs and induce AAA in ApoE−/− mice. Untargeted metabolomic analysis was performed using liquid chromatography–tandem mass spectrometry to detect metabolite changes. Differential metabolites were identified using orthogonal partial least squares discriminant analysis, and metabolic pathways were analyzed using Kyoto Encyclopedia of Genes and Genomes and metabolic set enrichment analysis. Results: In Ang II-treated VSMCs, 54 differential metabolites (24 upregulated; 30 downregulated) were identified, whereas 470 differential metabolites (206 upregulated; 264 downregulated) were detected in mouse aortas. Three metabolites—carnitine, lysophosphatidylcholine (0:0/20:4), and 5-hydroxyeicosatetraenoic acid—were common in both models and were enriched in bile secretion and tryptophan metabolism pathways. The carnitine–FXR signaling axis emerged as a potential therapeutic target. Conclusions: This study revealed Ang II-induced metabolic changes in VSMCs and their association with AAA pathology. The carnitine–FXR signaling axis may contribute to AAA development, providing new directions for diagnostic biomarkers and therapeutic targets. Future studies should validate these findings in human AAA samples to determine their clinical relevance. Full article

Our previous studies have shown that continuous infusion of angiotensin II (Ang II) in C57BL/6J mice causes dysfunction and a cachexia-like pathogenesis in both skeletal muscle and the left ventricle, which is significantly reduced by withaferin A (WFA), a steroidal lactone. However, it remains unknown whether WFA can reverse right ventricular (RV) dysfunction induced by Ang II. To determine the effects of WFA in attenuating Ang II-induced RV dysfunction, we employed a model in which continuous Ang II infusion via an osmotic pump in C57BL/6J mice induced cardiac remodeling. We then focused on investigating RV performance and structural changes using echocardiography and histopathological examination, as well as quantitative real-time PCR (qRT-PCR) for mRNA expression. Echocardiographic analysis demonstrated that Ang II significantly increased RV wall thickness and impaired RV systolic and diastolic function, as indicated by reductions in tricuspid annular plane systolic excursion, TV E/E′ ratio, RV S′, and RVOT VTI. The qRT-PCR analysis revealed marked upregulation of pro-fibrotic markers, including TGF-β, fibronectin, and collagen. WFA treatment restored RV functions and significantly attenuated Ang II-induced RV dysfunction and fibrosis. Our findings provide the first evidence that WFA attenuates Ang II-induced cachexia-like remodeling and dysfunction of the RV. These results position WFA as a compelling therapeutic candidate for cardiac cachexia, offering direct anti-fibrotic and cardioprotective benefits that warrant further translational development. Full article

Introduction: The pro-inflammatory cytokine interleukin-17A (IL-17A) has a key role in the inflammatory cascade and promotes vascular inflammation and dysfunction. In addition, IL-17A is centrally involved in several autoimmune diseases. IL-17A deficiency has been linked to reduced vascular inflammation associated with attenuated arterial hypertension under long-term angiotensin II (Ang II) exposure for four weeks. This is of interest as IL-17A is one factor linking several autoimmune diseases with cardiovascular comorbidity. So far, little is known about the effects of IL-17A during the early stages of vascular dysfunction development—an interval possibly representing an optimal therapeutic window. Methods: Mice lacking the IL-17A receptor alpha (IL-17RAdel) and wild-type counterparts were treated with Ang II for one week (1 mg/kg bodyweight/week). We assessed systemic oxidative stress formation and vascular function, as well as inflammatory cells in the vessel wall. In parallel, C57BL/6J mice treated with Ang II received anti-IL-17A therapy, to evaluate the same parameters. Results: Both IL-17RA-deficient mice and anti-IL-17A-treated C57BL/6J mice exhibited an attenuated oxidative stress response and mitigated vascular inflammation following one week of Ang II treatment. These effects did not significantly prevent the onset of Ang II-induced vascular dysfunction at that timepoint. Conclusions: After one week of Ang II treatment, antagonizing IL-17RA or IL-17A only partially reduced/attenuated the Ang II-induced effects on the vasculature. In the context of IL-17A-driven autoimmune diseases with associated vascular pathology, our findings suggest that anti-inflammatory therapies alone may not be sufficient to attenuate vascular impairment. A combined approach including agents with direct protective vascular effects may be required for effective intervention for the associated vascular comorbidity. Full article

Traffic-related air pollution (TRAP) is known to contribute to oxidative stress in the central nervous system (CNS) and has been linked to increased risk of Alzheimer’s disease (AD). Alterations in the renin–angiotensin system (RAS), specifically increased angiotensin II (Ang II) signaling via the angiotensin II type 1 (AT₁) receptor, are implicated in increased oxidative stress in the CNS via activation of NADPH oxidase (NOX). As exposure to TRAP may further elevate AD risk, we investigated whether exposure to inhaled mixed gasoline and diesel vehicle emissions (MVE) promotes RAS-dependent expression of factors that contribute to AD pathophysiology in an apolipoprotein E-deficient (ApoE^−/−) mouse model. Male ApoE^−/− mice (6–8 weeks old) on a high-fat diet were treated with either an ACE inhibitor (captopril, 4 mg/kg/day) or water and exposed to filtered air (FA) or MVE (200 µg PM/m³) for 30 days. MVE exposure elevated plasma Ang II, inflammation, and oxidative stress in the hippocampus, associated with increased levels of Aph-1 homolog B (APH1B), a gamma-secretase subunit, and beta-secretase 1 (BACE1), involved in Aβ production. Each of these endpoints was normalized with ACEi treatment. These findings indicate that TRAP exposure in ApoE^−/− mice drives a RAS- and NOX-dependent oxidative and inflammatory response and shifts Aβ processing towards an amyloidogenic profile before overt Aβ deposition, suggesting a potential therapeutic approach for air pollution-induced AD risk. Full article

Abdominal aortic aneurysm (AAA) is a lethal vascular disease characterized by intramural hemorrhage. This study delineates the signatures of heme and its metabolic imbalance related to progression and inflammation in AAA. Clinical analyses of patients undergoing open AAA surgery show that AAA patients exhibit vascular inflammation, with elevated serum CRP, IL-6, and heme levels correlating with the expression of heme-regulated gene Hmox1/HO-1 (heme oxygenase-1) in the affected aortic wall. Oxidation of hemoglobin to ferri state leading to accumulation of methemoglobin readily releasing heme occurs in human AAA and in angiotensin II (AngII)-induced AAA in apolipoprotein E-deficient mice. Transcriptomic analysis for AngII-induced AAA identifies upregulated genes predominantly enriched in inflammatory signaling, extracellular matrix degradation, oxidative stress pathways, and altered expression of genes related to heme metabolism including Hmox1. Immunohistochemistry for IL1β and TNFα confirms inflammatory activation within AAA tissues. The signatures of heme-responsive gene inductions, enhanced expression of HO-1 and H-ferritin, are detected. Mechanistic studies employing endothelial cells and smooth muscle cells reveal that heme exposure of resident cells markedly enhances the expression of IL1β and ICAM1, as well as the inflammasome component NLRP3, and such inflammatory response is controlled by HO-1. Intervention with Normosang (heme arginate), an HO-1 inducer, attenuates aneurysm progression, whereas HO-1 inhibition by Tin protoporphyrin IX abolishes this protection. Induction of HO-1 accompanied by elevated H-ferritin level also mitigated aortic wall inflammation as reflected by lowering IL1β and TNFα. These findings highlight the heme-HO-1-H-ferritin axis as an element of AAA pathogenesis and a potential therapeutic target. Full article

Background: Myocardial fibrosis, a central pathological process leading to heart failure, lacks specific mechanism-based therapies. Although the anti-inflammatory activity of the natural compound protocatechuic acid is recognized, its direct anti-fibrotic mechanism, particularly concerning the critical role of endothelial–mesenchymal transition (EndMT), remains unexplored. This study aimed to investigate the protective effects and underlying mechanisms of protocatechuic acid. Methods: The study employed both in vivo and in vitro models. For in vivo evaluation, a rat model of myocardial fibrosis was induced by isoproterenol hydrochloride (ISO). For in vitro analysis, human umbilical vein endothelial cells (HUVECs) were stimulated with angiotensin II (Ang II) and subjected to siRNA-mediated histone deacetylase 1 (HDAC1) knockdown, alongside a co-culture model involving HUVECs and the AC16 human cardiomyocyte cells. Additionally, molecular docking and dynamics simulations were performed to evaluate the binding affinity and stability of protocatechuic acid with the target protein, HDAC1. Results: In vivo, protocatechuic acid significantly improved cardiac function, attenuated pathological injury, and reduced collagen deposition in ISO-induced fibrotic rats. It also potently suppressed inflammatory responses and inhibited the EndMT process. These beneficial effects were associated with decreased HDAC1 and increased GATA binding protein 4 (GATA4) expression in perivascular regions, which suggests the modulation of the HDAC1/GATA4 pathway. In vitro, protocatechuic acid suppressed Ang II-induced endothelial inflammation in HUVECs. This effect was replicated by HDAC1 knockdown, thus confirming that the HDAC1/GATA4 pathway mediates its anti-inflammatory action at the cellular level. Furthermore, molecular docking and dynamics simulations indicated that protocatechuic acid stably binds to a key target, HDAC1. Conclusions: Protocatechuic acid alleviates inflammation and EndMT by inhibiting the HDAC1/GATA4 signaling pathway, thereby preserving cardiac function and retarding the progression of myocardial fibrosis. These findings provide a theoretical and experimental foundation for the potential application of protocatechuic acid in treating cardiovascular diseases. Full article

Aortic aneurysms and dissections are devastating vascular diseases with high mortality, yet no pharmacological therapy has proven effective in halting growth or preventing rupture. Surgical and endovascular repair remain the only treatment options for advanced disease. Animal models have been indispensable in defining mechanisms and testing candidate therapies, but the diversity of protocols, strain-dependent variability, and heterogeneous endpoints complicate interpretation and translation. This review provides an update focused on how to match models to specific research questions. We critically compare commonly used abdominal aortic aneurysm (AAA) models (angiotensin II ± hyperlipidemia, elastase, calcium chloride, β-aminopropionitrile BAPN hybrids, and mineralocorticoid agonist/fludrocortisone models) with thoracic aortopathy and dissection models (BAPN alone or with AngII, genetic models including Marfan and smooth muscle contractile mutations, and AngII + TGF-β blockade). We highlight practical considerations on segment specificity, rupture incidence, lipid dependence, comorbidities, and outcome measurement, with emphasis on rigor and reporting standards. A translational thread on platelet–intraluminal thrombus biology, including the emerging biomarker and therapeutic targets such as glycoprotein VI (GPVI), is integrated across models. We offer a decision grid and rigor checklist to harmonize model use, enhance reproducibility, and accelerate translation. Full article

This study aimed to identify novel angiotensin-converting enzyme (ACE)-inhibitory peptides from royal jelly proteins (RJPs) by integrating in silico digestion, virtual screening, and in vitro evaluation. Three major royal jelly proteins (MRJP1-3) were subjected to in silico digestion using 16 enzymatic systems, yielding 1411 unique peptides. Virtual screening based on predicted bioactivity, toxicity, water solubility, and ADMET profiles resulted in the selection of 27 candidate peptides. Molecular docking revealed strong binding affinities for these peptides compared with the positive control captopril, among which PYPDWSFAK and RPYPDWSF exhibited potent ACE-inhibitory activity, with IC₅₀ values of 110 ± 1.02 μmol/L and 204 ± 0.61 μmol/L, respectively. Kinetic analysis indicated that PYPDWSFAK acts as a mixed-type ACE inhibitor. Docking visualization demonstrated that PYPDWSFAK forms multiple hydrogen bonds with key residues in the ACE active pocket and directly coordinates with the catalytic Zn²⁺ ion. Cellular assays showed that PYPDWSFAK was non-cytotoxic, suppressed Ang II–induced endothelial cell migration, restored NO and ET-1 balance, and enhanced SOD and GSH-Px activities. Overall, this study enriches the repertoire of ACE-inhibitory peptides derived from royal jelly proteins. Furthermore, PYPDWSFAK is identified as a promising ACE-inhibitory peptide with potential for incorporation into natural antihypertensive ingredients or functional foods. Full article

The role of hepatic stellate cells (HSCs) in the development of liver fibrosis and portal hypertension has already been largely clarified. Activation of HSCs might lead to self-increased proliferation and enhanced contractile activity, causing their transdifferentiation into myofibroblasts (activated HSCs), which drive the release of proinflammatory mediators, collagen, proteoglycans, and other extracellular matrix components, responsible for liver fibrosis and portal hypertension development. A possible mechanism for the pathophysiological role of HSCs in liver fibrosis might be autophagy, which breaks down the lipid droplets in quiescent HSCs, releasing fatty acids and providing the energy required for their activation into myofibroblasts. An ever-growing body of scientific evidence indicates that renin–angiotensin system (RAS) blockade can inhibit the evolution of fibrosis in patients with chronic liver diseases, and especially metabolic dysfunction-associated steatotic liver disease (MASLD), although the use of both angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs) has not yet been officially identified as a potential fibrosis treatment. More recently, researchers have shown that overexpression of ACE2, induced by ACE inhibitor (ACEI) activity and leading to the degradation of angiotensin (ANG) II into ANG 1-7, inhibition of autophagy and consequent HSC activation, might prevent liver fibrosis development. This review aims to summarize recent pre-clinical studies and to identify a common thread underlying the latest scientific evidence in this field. Full article

Background: Hypertension and its complications are a major global health problem, and natural compounds with vasorelaxant effects are being investigated as potential antihypertensive agents. Objective: This study aimed to determine whether rosmarinic acid (RA) induces vasorelaxation in the rat thoracic aorta and to elucidate the underlying mechanisms. Methods: Isolated thoracic aortic rings, with or without endothelium, were precontracted with phenylephrine and subsequently exposed to cumulative concentrations of RA. The roles of endothelium-derived factors, potassium channels, and calcium signaling were evaluated using selective pharmacological inhibitors and activators. In addition, the involvement of the AMPK pathway, adenylate cyclase/cAMP pathway, PKC signaling, β-adrenergic receptors, muscarinic receptors, and angiotensin II in RA-induced vasorelaxation was investigated. Results: RA induced a concentration-dependent vasorelaxation in endothelium-intact thoracic aortic rings (p < 0.001; pD₂ = 7.67 ± 0.04). The vasorelaxant effect of RA was attenuated in endothelium-denuded vessels (pD2: 5.26 ± 0.18). The relaxation response was significantly attenuated by inhibitors of the PI3K/Akt/eNOS/NO/cGMP pathway and by blockers of BK_Ca, IK_Ca, and Kv potassium channels (p < 0.001). Furthermore, RA markedly inhibited both extracellular Ca²⁺ influx and intracellular Ca²⁺ release from the sarcoplasmic reticulum (p < 0.001). RA incubation also significantly reduced the contractions induced by angiotensin II (Ang II) and by the PKC activator PMA (p < 0.001). Other tested pathways had no significant influence on the vasorelaxant effect of RA (p > 0.05). Conclusions: These findings demonstrate that rosmarinic acid induces both endothelium-dependent and endothelium-independent vasorelaxation in the rat thoracic aorta through activation of the PI3K/Akt/eNOS/NO/cGMP pathway, opening of BK_Ca, IK_Ca, and Kv potassium channels, and suppression of Ca²⁺ mobilization. Additionally, inhibition of PKC- and angiotensin II-mediated vascular contraction contributes to RA-induced vasorelaxation. RA may therefore have therapeutic potential in the management of hypertension. Full article

Hypertension is a leading risk factor for cardiovascular disease and is associated with maladaptive cardiac remodeling, including hypertrophy and fibrosis. The roles of the receptor for advanced glycation end-products (RAGE) and the small GTPase Rap1a in angiotensin II (AngII)-induced remodeling remain unclear. This study examined how RAGE and Rap1a influence cardiac responses to AngII using wild-type (WT), RAGE knockout (RAGE KO), and Rap1a knockout (RapKO) mice. Cardiac structure and function were evaluated following AngII infusion. RapKO mice were protected from AngII-induced hypertrophy, whereas RAGE KO mice exhibited altered remodeling patterns. AngII consistently increased left ventricular wall thickness across all genotypes, indicating that structural remodeling is primarily treatment-driven. Measures of cardiac output and stroke volume also changed significantly with AngII, suggesting hemodynamic load as a key driver of functional adaptation. In contrast, diastolic functional parameters were genotype-dependent and remained stable with AngII exposure, demonstrating an intrinsic influence of RAGE and Rap1a on myocardial relaxation. These findings highlight distinct roles for RAGE and Rap1a in modulating hypertensive cardiac remodeling and may parallel human hypertensive heart disease, where increased RAGE and Rap1a expression associate with fibrosis and impaired relaxation. Targeting the crosstalk between the RAGE-AT1R axis and the cAMP-EPAC-Rap1a pathway may offer therapeutic potential to reduce adverse cardiac remodeling in hypertension. Full article

This study investigated the region-specific roles of transforming growth factor-β2 (TGF-β2) and angiotensin II (AngII) in extracellular matrix (ECM) remodeling and inflammatory responses within scleral tissues surrounding the optic nerve head (ONH), using primary human fibroblasts from posterior sclera, peripapillary sclera (ppScl), and fibroblast-like cells from lamina cribrosa (LC). In vivo validation was performed in a chronic ocular hypertension rat model. Fibrotic and inflammatory markers were analyzed by Western blotting, quantitative PCR, and immunocytochemistry following TGF-β2 or AngII stimulation, and in vivo effects were assessed after subtenon injection of pathway-specific inhibitors. TGF-β2 induced robust upregulation of α-smooth muscle actin, collagen type I, and fibronectin across all scleral regions, whereas AngII elicited regionally confined pro-inflammatory responses, particularly in the LC and ppScl, characterized by increased cyclooxygenase-2 expression. Inhibition of either pathway reduced ECM deposition in vivo, but only AngII blockade significantly attenuated glial activation and preserved retinal ganglion cells. These findings demonstrate that TGF-β2 predominantly drives fibrosis, while AngII promotes region-specific neuroinflammation, and that inflammation, rather than fibrosis alone, plays a critical role in glaucomatous neurodegeneration. Targeting both fibrotic and inflammatory mechanisms in a region-specific manner may offer improved neuroprotection in glaucoma. Full article