Vascular Tension Research Articles

Cleistanthin A causes peripheral vasoconstriction and myocardial depression in isolated tissue preparations

Background Cleistanthus collinus is a poisonous shrub commonly used for deliberate self-harm in rural south India. Boiled decoction or a paste made from its leaves is used for suicide. Cleistanthoside A and Cleistanthin A are the major toxins identified from this plant. In this study, we disclose the mechanism of Cleistanthin A toxicity and concentrations of the two toxins in different extracts of Cleistanthus collinus. Methods The effect of Cleistanthin A was studied on isolated goat leg arteries using two different preparations namely transverse cylinder and longitudinal strip. The influence of Cleistanthin A on peripheral vascular resistance and myocardial contractility was evaluated by rat hind limb and isolated rat heart experiments, respectively. For the quantification of toxins, five different extracts of C. collinus leaves were prepared. The extracts were subjected to analytical HPLC to quantify Cleistanthoside A and Cleistanthin A. Results and Conclusion Cleistanthin A increased vascular tension in transverse cylinder preparation and increased peak, trough and mean aortic pressures in the rat hind limb preparations. In isolated rat heart experiments, there was an increase in diastolic and mean ventricular pressure with a significant decrease in ventricular pulse pressure. These observations suggest that the hypotension in C. collinus poisoning patients may be due to cardiotoxicity and not due to vasodilation as is currently believed. Quantification of different extracts showed that boiled extracts had higher quantities of Cleistanthoside A whereas crushed leaf extracts yielded significantly higher amounts of Cleistanthin A.

Role of cardiopulmonary interactions in development of ventilator-induced lung injury-Experimental evidence and clinical Implications.

Ventilator-induced lung injury (VILI) impacts outcomes in ARDS and optimization of ventilatory strategies improves survival. Decades of research has identified various mechanisms of VILI, largely focusing on airspace forces of plateau pressure, tidal volume and driving pressure. Experimental evidence indicates the role of adverse cardiopulmonary interaction during mechanical ventilation, contributing to VILI genesis mostly by modulating pulmonary vascular dynamics. Under passive mechanical ventilation, high transpulmonary pressure increases afterload on right heart while high pleural pressure reduces the RV preload. Together, they can result in swings of pulmonary vascular flow and pressure. Altered vascular flow and pressure result in increased vascular shearing and wall tension, in turn causing direct microvascular injury accompanied with permeability to water, proteins and cells. Moreover, abrupt decreases in airway pressure, may result in sudden overperfusion of the lung and result in similar microvascular injury, especially when the endothelium is stretched or primed at high positive end-expiratory pressure. Microvascular injury is universal in VILI models and presumed in the diagnosis of ARDS; preventing such microvascular injury can reduce VILI and impact outcomes in ARDS. Consequently, developing cardiovascular targets to reduce macro and microvascular stressors in the pulmonary circulation can potentially reduce VILI. This paper reviews the role of cardiopulmonary interaction in VILI genesis.

Free Radical and Viral Infection: A Review from the Perspective of Ferroptosis.

Free radicals, including reactive oxygen species (ROS) and reactive nitrogen species (RNS), play critical roles in various physiological activities such as cell differentiation, apoptosis, and vascular tension when existing in cells at low levels. However, excessive amounts of free radicals are harmful, causing DNA damage, lipid peroxidation, protein degeneration, and abnormal cell death. Certain viral infections induce cells to produce excessive free radicals, which in multiple ways help the virus to replicate, mature, and exit. Iron is a necessary element for many intracellular enzymes, involved in both cellular activities and viral replication. Ferroptosis, a programmed cell death mode distinct from apoptosis, necrosis, and pyroptosis, is characterized by lipid peroxide accumulation and damage to the antioxidant system, affecting many cellular processes. Viral infection commonly manifests as decreased glutathione (GSH) content and down-regulated glutathione peroxidase 4 (GPX4) activity, similar to ferroptosis. Recent studies have suggested a possible relationship among free radicals, viral infections and ferroptosis. This review aims to elucidate the molecular mechanism linking free radicals and ferroptosis during viral infections and provide a new theoretical basis for studying viral pathogenesis and control.

MIR-107/HMGB1/FGF-2 axis responds to excessive mechanical stretch to promote rapid repair of vascular endothelial cells

The increase of vascular wall tension can lead to endothelial injury during hypertension, but its potential mechanism remains to be studied. Our results of previous study showed that HUVECs could induce changes in HMGB1/RAGE to resist abnormal mechanical environments in pathological mechanical stretching. In this study, we applied two different kinds of mechanical tension to endothelial cells using the in vitro mechanical loading system FlexCell-5000T and focused on exploring the expression of miR-107 related pathways in HUVECs with excessive mechanical tension. The results showed that miR-107 negatively regulated the expression of the HMGB1/RAGE axis under excessive mechanical tension. Excessive mechanical stretching reduced the expression of miR-107 in HUVECs, and increased the expression of the HMGB1/RAGE axis. When miR-107 analog was transfected into HUVECs with lipo3000 reagent, the overexpression of miR-107 slowed down the increase of the HMGB1/RAGE axis caused by excessive mechanical stretching. At the same time, the overexpression of miR-107 inhibited the proliferation and migration of HUVECs to a certain extent. On the contrary, when miR-107 was silent, the proliferation and migration of HUVECs showed an upward trend. In addition, the study also showed that under excessive mechanical tension, miR-107 could regulate the expression of FGF-2 by HMGB1. In conclusion, these findings suggest that pathological mechanical stretching promote resistance to abnormal mechanical stimulation on HUVECs through miR-107/HMGB1/RAGE/FGF-2 pathway, thus promote vascular repair after endothelial injury. The suggest that miR-107 is a potential therapeutic target for hypertension.

PFI-3 induces vasorelaxation with potency to reduce extracellular calcium influx in rat mesenteric artery.

PFI-3 is a small-molecule inhibitor that targets the bromodomains (BRDs) of Brahma-related gene 1 (BRG1). This monomeric compound, which has high selectivity and potent cellular effects, has recently been developed. Although PFI-3 has been reported as a potential therapeutic agent targeting thrombomodulin, its role in the regulation of vascular function remains unknown. Therefore, we aimed to investigate the impact of PFI-3 on arterial vessel tone. A microvascular tension measurement device (DMT) was utilized to identify alterations in vascular tension within the mesenteric artery. To detect variations in cytosolic [Ca2+]i, a Fluo-3/AM fluorescent probe and fluorescence microscope were employed. Additionally, whole-cell patch clamp techniques were utilized to evaluate the activity of L-type voltage-dependent calcium channels (VDCCs) in cultured arterial smooth muscle cells (A10 cells). PFI-3 exerted a dose-dependent relaxation effect on rat mesenteric arteries with both intact and denuded endothelium after phenylephrine (PE)- and high-K+-induced constriction. PFI-3-induced vasorelaxation was not affected by the presence of L-NAME/ODQ or K+ channel blockers (Gli/TEA). PFI-3 abolished Ca2+-induced contraction on endothelium-denuded mesenteric arteries preincubated by PE in Ca2+-free solution. Incubation with TG had no impact on PFI-3-induced vasorelaxation pre-contracted by PE. PFI-3 reduced Ca2+-induced contraction on endothelium-denuded mesenteric arteries pre-incubated by KCl (60mM) in Ca2+-free solution. PFI-3 declined extracellular calcium influx in A10 cells detected by Fluo-3/AM fluorescent probe and fluorescence microscope. Furthermore, we observed that PFI-3 decreased the current densities of L-type VDCC by whole-cell patch clamp techniques. PFI-3 blunted PE and high K+-induced vasoconstriction independent of endothelium on rat mesenteric artery. The vasodilatory effect of PFI-3 may be attributed to its inhibition of VDCCs and receptor-operated calcium channels (ROCCs) on vascular smooth muscle cells (VSMCs).

Gastrodin attenuates angiotensin II-induced vascular contraction and MLCK/p-MLC2 pathway activation

Context Gastrodin has been used as antihypertension therapy in China; however, the mechanisms underlying the effects of gastrodin have yet to be fully elucidated. Objective To explore the therapeutic efficiency of gastrodin as an antihypertensive and determine the mechanisms underlying this effect. Materials and methods C57BL/6 mice were continuously administered angiotensin II (Ang II) (500 ng/kg/min) to induce hypertension. Mice were randomly divided into control, Ang II and Ang II + gastrodin groups. Mice received intragastric administration of gastrodin (5 mg/kg) or double distilled water once a day for 4 weeks. Blood pressure, pulse wave velocity (PWV), thickness of the abdominal aorta, pathological morphology and differential expression transcripts (DETs) were assessed. Abdominal aorta rings and primary isolated vascular smooth muscle cells were subjected to Ang II stimulation to induce hypertension as ex vivo and in vitro models, respectively. Vascular ring tension, release of Ca2+ and levels of proteins involved in the myosin light chain kinase (MLCK)/phospho-myosin light chain 2 (p-MLC2) pathway were determined. Results Gastrodin treatment attenuated increases in blood pressure, PWV and thickness of the abdominal aorta. Treatment with gastrodin resulted in 2785 DETs and the enrichment of vascular contraction and calcium signalling pathways. Gastrodin treatment attenuated Ang II-induced vasoconstriction, produced a norepinephrine-precontracted vasodilation effect (attenuated by verapamil), and reduced intracellular Ca2+ release. Furthermore, gastrodin suppressed activation of the MLCK/p-MLC2 pathway in vivo and in vitro. Conclusions Gastrodin treatment lowers blood pressure, suppresses Ang II-induced vascular contraction and MLCK/p-MLC2 pathway activation, thereby demonstrating the mechanisms underlying the therapeutic efficacy of gastrodin as an antihypertensive.

The accumulated oxygen deficit as an indicator of the ischemic retinal insult

We here attempt to improve quantification of the ischemic retinal insult, that is, what is imposed on the retinal tissue by ischemia, especially in experimental models of ischemia. The ischemic retinal insult initiates the ischemic retinal injury (or outcome). Accordingly, it is reasonable to assume that the better the quantification of the insult, the better the correlation with, and thereby estimation of, the injury. The insult seldom has been quantified in terms of the relevant physiological factors, especially in connection with the rate of oxygen delivery (DO2). We here propose the accumulated oxygen deficit (AO2D) as an indicator of the ischemic retinal insult. We hypothesized that AO2D is correlated with the rate of oxygen metabolism measured 1 h after reperfusion following an episode of ischemia (MO2_1_Hr). Previously, we showed that MO2_1_Hr is related to the electroretinogram amplitude and the retinal thickness when they are measured seven days after reperfusion. We studied 27 rats, as well as 26 rats from our published data on retinal ischemia in which we had measurements of DO2 and duration of ischemia (T) of various levels and durations. We also measured DO2 in 29 rats treated with sham surgery. Ischemia was induced by either ipsilateral or bilateral common carotid artery occlusion or by ophthalmic artery occlusion, which gave a wide range of DO2. DO2 and MO2_1_Hr were evaluated based on three types of images: 1) red-free images to measure vessel diameters, 2) fluorescence images to estimate blood velocities by the displacement of intravascular fluorescent microspheres over time, and 3) phosphorescence images to quantify vascular oxygen tension from the phosphorescence lifetime of an intravascular oxygen sensitive phosphor. Loss of oxygen delivery (DO2L) was calculated as the difference between DO2 under normal/sham condition and DO2 during ischemia. AO2D, a volume of oxygen, was calculated as the product DO2L and T. Including all data, the linear relationship between AO2D and MO2_1_Hr was significant (R2 = 0.261, P = 0.0003). Limiting data to that in which T or DO2L was maximal also yielded significant relationships, and revealed that DO2L at a long duration of ischemia contributed disproportionately more than T to MO2_1_Hr. We discuss the potential of AO2D for quantifying the ischemic retinal insult, predicting the ischemic retinal injury and evaluating the likelihood of infarction.

Pericytes protect rats and mice from sepsis-induced injuries by maintaining vascular reactivity and barrier function: implication of miRNAs and microvesicles

BackgroundVascular hyporeactivity and leakage are key pathophysiologic features that produce multi-organ damage upon sepsis. We hypothesized that pericytes, a group of pluripotent cells that maintain vascular integrity and tension, are protective against sepsis via regulating vascular reactivity and permeability.MethodsWe conducted a series of in vivo experiments using wild-type (WT), platelet-derived growth factor receptor beta (PDGFR-β)-Cre + mT/mG transgenic mice and Tie2-Cre + Cx43flox/flox mice to examine the relative contribution of pericytes in sepsis, either induced by cecal ligation and puncture (CLP) or lipopolysaccharide (LPS) challenge. In a separate set of experiments with Sprague–Dawley (SD) rats, pericytes were depleted using CP-673451, a selective PDGFR-β inhibitor, at a dosage of 40 mg/(kg·d) for 7 consecutive days. Cultured pericytes, vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) were used for mechanistic investigations. The effects of pericytes and pericyte-derived microvesicles (PCMVs) and candidate miRNAs on vascular reactivity and barrier function were also examined.ResultsCLP and LPS induced severe injury/loss of pericytes, vascular hyporeactivity and leakage (P < 0.05). Transplantation with exogenous pericytes protected vascular reactivity and barrier function via microvessel colonization (P < 0.05). Cx43 knockout in either pericytes or VECs reduced pericyte colonization in microvessels (P < 0.05). Additionally, PCMVs transferred miR-145 and miR-132 to VSMCs and VECs, respectively, exerting a protective effect on vascular reactivity and barrier function after sepsis (P < 0.05). miR-145 primarily improved the contractile response of VSMCs by activating the sphingosine kinase 2 (Sphk2)/sphingosine-1-phosphate receptor (S1PR)1/phosphorylation of myosin light chain 20 pathway, whereas miR-132 effectively improved the barrier function of VECs by activating the Sphk2/S1PR2/zonula occludens-1 and vascular endothelial-cadherin pathways.ConclusionsPericytes are protective against sepsis through regulating vascular reactivity and barrier function. Possible mechanisms include both direct colonization of microvasculature and secretion of PCMVs.

COMMD5 is involved in the mechanisms of hypotension after parathyroidectomy in patients receiving hemodialysis

BackgroundSecondary hyperparathyroidism (SHPT) is a common complication of end-stage renal disease. Parathyroidectomy (PTx) is often employed for treatment of severe SHPT. However, PTx may cause hypotension via unknown mechanisms. COMM domain-containing protein 5 (COMMD5) in the parathyroid glands has been linked to blood pressure regulation of spontaneously hypertensive rats. ObjectiveTo explore the relationship between COMMD5 levels and reduced BP after PTx in patients receiving hemodialysis (HD). Methods and results(1) The study cohort included 31 patients receiving HD who underwent PTx. Serum COMMD5 levels were higher post-PTx vs. pre-PTx. (2) Sprague-Dawley rats (n = 22) were assigned to a 5/6 nephrectomy group or sham surgery group, vascular rings of the thoracic aorta from rats with CKD were incubated with COMMD5, and changes in vascular tension were compared. COMMD5 inhibited vasoconstriction of vascular rings with intact endothelium, but had no effect on vascular rings without the endothelium. (3) Human umbilical vein endothelial cells were stimulated with COMMD5 or small interfering RNA (siRNA). The expression levels of atrial natriuretic peptide (ANP) and endothelial nitric oxide synthase (eNOS) were up-regulated and down-regulated, respectively. ConclusionsSerum COMMD5 levels were increased after PTx in SHPT patients. COMMD5 promoted high expression of ANP and eNOS in endothelial cells, leading to vasodilation and resulting in hypotension.

Role of PVAT in obesity-related cardiovascular disease through the buffering activity of ATF3.

Thoracic aortic perivascular adipose tissue (PVAT) is an adipose organ exhibiting similarities to brown adipose tissue (BAT), including cellular morphology and thermogenic gene expression. However, whether the PVAT phenotype is indistinguishable from the BAT phenotype in physiological vasculature remains unclear. We demonstrated that PVAT is distinguishable from classical BAT, given its specific vessel-tone-controlling function. Activating transcription factor 3 (ATF3) is a key factor in hypertension. Compared with wild-type mice, ATF3-deficient (ATF3 -/- ) mice fed a high-fat diet exhibited elevated mean arterial pressure, increased monocyte chemoattractant protein-1 expression and hypertrophy, plus abnormal fatty tissue accumulation in the thoracic aortic PVAT, and enhanced vascular wall tension and vasoconstrictive responses of potassium chloride, U46619, and norepinephrine in isolated aortic rings, which were restored after administration of adeno-associated ATF3 vector. We suggest that PVAT, not BAT, modulates obesity-related vascular dysfunction. ATF3 within PVAT could provide new insights into the pathophysiology of obesity-related cardiovascular diseases.

Pathogenic Mechanisms of Pulmonary Arterial Hypertension: Homeostasis Imbalance of Endothelium-Derived Relaxing and Contracting Factors.

Pulmonary arterial hypertension (PAH) is a progressive and fatal disease. Sustained pulmonary vasoconstriction and concentric pulmonary vascular remodeling contribute to the elevated pulmonary vascular resistance and pulmonary artery pressure in PAH. Endothelial cells regulate vascular tension by producing endothelium-derived relaxing factors (EDRFs) and endothelium-derived contracting factors (EDCFs). Homeostasis of EDRF and EDCF production has been identified as a marker of the endothelium integrity. Impaired synthesis or release of EDRFs induces persistent vascular contraction and pulmonary artery remodeling, which subsequently leads to the development and progression of PAH. In this review, the authors summarize how EDRFs and EDCFs affect pulmonary vascular homeostasis, with special attention to the recently published novel mechanisms related to endothelial dysfunction in PAH and drugs associated with EDRFs and EDCFs.

Effects of different preservation methods of human iliac veins.

With the progress of vascular anastomosis technology, the radical resection surgery of cancer combining with vascular resection and reconstruction has been focused by surgeon. As a natural substitute material for blood vessel, vascular allografts have good vascular compliance and histocompatibility. Generally, the donated veins could not be used immediately, and need to be well preserved. So, it is greatly significant to do research in the preservation effects of different preservation methods on veins. In this study, the effects of different preservative methods of human iliac veins were compared and analyzed in terms of cell viability, vascular wall structure and tension resistance. The donated human iliac veins were randomly divided into three groups: Cold Storage Group (4 °C) (CSG), Frozen Storage Group (-186 °C) (FSG)and Fresh Control Group (FCG). Six detection time-points of preservation for 1, 3, 5, 7, 14, 28days were set respectively. There are ten samples in each group and each time-point separately. Survival and apoptosis of vascular cell were evaluated by MTT assay and Tunel fluorescence staining. Tensile test was used to evaluate mechanical properties of vessels. The changes of vascular endothelial cells, smooth muscle cells, collagen fibers and elastic fibers were evaluated by HE staining, Masson staining and EVG staining. Furthermore, the changes of organelles were observed by transmission electron microscope. With the extension of preservation period, the vascular cell viability and tension resistance of two groups decreased, and the apoptotic cells increased gradually. The apoptosis index of CSG was higher than FSG at each time point (P < 0.05). In terms of cell viability, CSG was higher within 3days (P < 0.05), both groups were same between 3 and 14days, and then CSG lower than FSG after 14days (P < 0.05). In terms of tension resistance, CSG was stronger than FSG (P < 0.05) in first 7days, both groups were same in 2nd week, and then CSG was weaker in 4th week (P < 0.05). In terms of vascular wall structure, in CSG, vascular endothelial cells were damaged and shed, smooth muscle cells were edema after 14days, but the cell membrane and intercellular connection were still intact. In 4th week, endothelial cells were completely damaged and shed, the boundary of smooth muscle cell membrane was unclear, intercellular connection was damaged. Moreover, organelles were destroyed and disappeared, perinuclear condensation of chromatin was observed, and some cells had incomplete nuclear membrane or nuclear fragmentation; However, there were no obvious changes in the FSG within 28days. Finally, local exfoliation and destruction of endothelial cells and edema-like changes of organelles were observed; the collagen fibers and elastic fibers of blood vessels in the two groups had no obvious damage and change within 28days. For excised human iliac vein, cold and frozen storage can effectively preserve the cell viability, wall structure and tension resistance of blood vessels. With the extension of preservation time, the related performance of vessels declined in varying degrees. Within first week, the effect of cold storage is better than frozen storage, but frozen storage is significantly better than cold storage after 2weeks.

Piezo1 in endothelial cells is involved in vitamin D-induced vascular calcification

The relationship between the Piezo1 channel of vascular endothelial cells and vascular calcification is unknown. In this study, after subcutaneous injection of vitamin D for 10 consecutive days, the mice showed an increase in serum calcium, aortic calcium content, vascular tension and pulse wave velocity. Piezo1channel antagonist, GsMTx4 alleviated arteriosclerosis and decreased the aortic calcium content, while Piezo1 agonist Yoda1 produced opposite effect. In addition, activation of Piezo1 by Yoda1 impaired the function of human umbilical vein endothelial cells (HUVECs), as evidenced by further decreased production of NO, reduction in expression levels of eNOS, MMP-2, PCNA and VEGFA. When co-culture of HUVECs and vascular smooth muscle cells (VSMCs), activation of Piezo1 in HUVECs enhanced expression levels of calcification-related SOX9 and Runx2 genes, increased ALP activity and calcium deposition in VSMCs. We concluded that Piezo1 in endothelial cells is involved in the pathogenesis of vascular calcification. This study provides a new experimental basis for the prevention and treatment of vascular calcification.

Restoration of Mitochondrial Function Is Essential in the Endothelium-Dependent Vasodilation Induced by Acacetin in Hypertensive Rats.

Mitochondrial dysfunction in the endothelium contributes to the progression of hypertension and plays an obligatory role in modulating vascular tone. Acacetin is a natural flavonoid compound that has been shown to possess multiple beneficial effects, including vasodilatation. However, whether acacetin could improve endothelial function in hypertension by protecting against mitochondria-dependent apoptosis remains to be determined. The mean arterial pressure (MAP) in Wistar Kyoto (WKY) rats, spontaneously hypertensive rats (SHR) administered with acacetin intraperitoneally for 2 h or intragastrically for six weeks were examined. The endothelial injury was evaluated by immunofluorescent staining and a transmission electron microscope (TEM). Vascular tension measurement was performed to assess the protective effect of acacetin on mesenteric arteries. Endothelial injury in the pathogenesis of SHR was modeled in HUVECs treated with Angiotensin II (Ang II). Mitochondria-dependent apoptosis, the opening of Mitochondrial Permeability Transition Pore (mPTP) and mitochondrial dynamics proteins were determined by fluorescence activated cell sorting (FACS), immunofluorescence staining and western blot. Acacetin administered intraperitoneally greatly reduced MAP in SHR by mediating a more pronounced endothelium-dependent dilatation in mesenteric arteries, and the vascular dilatation was reduced remarkably by NG-nitro-L-arginine methyl ester (L-NAME), an inhibitor of NO synthesis. While acacetin administered intragastrically for six weeks had no apparent effect on MAP, it improved the endothelium-dependent dilatation in SHR by activating the AKT/eNOS pathway and protecting against the abnormalities of endothelium and mitochondria. Furthermore, acacetin remarkably inhibited Ang II induced apoptosis by inhibiting the increased expression of Cyclophilin D (CypD), promoted the opening of mPTP, ROS generation, ATP loss and disturbance of dynamin-related protein 1 (DRP1)/optic atrophy1 (OPA1) dynamics in HUVECs. This study suggests that acacetin protected against endothelial dysfunction in hypertension by activating the AKT/eNOS pathway and modulating mitochondrial function by targeting mPTP and DRP1/OPA1-dependent dynamics.

Effects Of Aerobic Exercise On BkCa Channels In Arterial Myocytes From Akap150 Smki Mouse

Large-conductance Ca2+-activated K+ channels (BKCa) play a key role in the maintenance of arterial tension. A-kinase anchoring protein 150 (AKAP150) participates in remodeling of ion channels and regulation of vascular tension. However, the role of vascular smooth muscle AKAP150 in aerobic exercise-mediated BKCa channel function is unclear. PURPOSE: To investigate the role of vascular smooth muscle AKAP150 in aerobic exercise-induced arterial and BKCa channel function restoration. METHODS: Using embryonic stem cell targeting technology, we generated the AKAP150 smooth muscle specific knock-in mice (AKAP150 smKI). The wild type (WT) and AKAP150 smKI mice were randomly assigned to sedentary (SED) or exercise (EX) group. WT-EX and AKAP150 smKI-EX were subjected to 12 weeks moderate-intensity aerobic training, and the vascular molecular and functional properties of mice were evaluated after training. RESULTS: The systolic blood pressure (SBP) of 3-month-old AKAP150 smKI mice was higher than that of WT (115.3 ± 0.3 vs. 106.9 ± 0.2 mmHg, p < 0.01). After training, the SBP decreased in AKAP150 smKI-EX (123.9 ± 0.6 vs. 118.4 ± 0.1 mmHg, p < 0.01) and WT-EX (114.1 ± 0.1 vs. 110.1 ± 0.4 mmHg, p < 0.01). AKAP150 smooth muscle specific knock-in significantly reduced the voltage dependence and calcium sensitivity of BKCa channel. Compared with WT-SED, V1/2 enlarged (45.69 ± 1.58 vs. 64.14 ± 2.65 mV, p < 0.01) and Kd increased (0.25 ± 0.09 vs. 1.53 ± 0.49 μmol/L, p < 0.01) in AKAP150 smKI. Aerobic training can effectively reverse these changes, with decreasing V1/2 (55.97 ± 4.30 mV, p < 0.01) and Kd (0.24 ± 0.05 μmol/L, p < 0.01) in AKAP150 smKI-EX. Meanwhile, the expression of AKAP150 was increased (~3.20-fold, p < 0.01), BKCa channel β1 subunit and β1/α subunit ratio were decreased (~0.51; ~0.60-fold, p < 0.01) in AKAP150 smKI-SED. After exercise, the expression of AKAP150 was decreased (~0.69-fold, p < 0.01), β1 subunit and β1/α ratio were increased (~2.08; ~2.43-fold, p < 0.01) in AKAP150smKI-EX. In WT-EX, β1 subunit and β1/α ratio were increased (~1.27; ~1.57-fold, p < 0.01). CONCLUSION: Aerobic training decreases the expression of AKAP150, and so upregulates the expression and function of BKCa channel in VSMCs, leading to the reduction of blood pressure. Supported by the National Natural Science Foundation of China 31771312, 32071174.

Retinal Vascular Physiology Biomarkers in a 5XFAD Mouse Model of Alzheimer's Disease.

Background: Alzheimer’s disease (AD) is a neurodegenerative disorder that affects the brain and retina and lacks reliable biomarkers for early diagnosis. As amyloid beta (Aβ) manifestations emerge prior to clinical symptoms and plaques of amyloid may cause vascular damage, identification of retinal vascular biomarkers may improve knowledge of AD pathophysiology and potentially serve as therapeutic targets. The purpose of the current study was to test the hypothesis that retinal hemodynamic and oxygen metrics are altered in 5XFAD mice. Methods: Thirty-two male mice were evaluated at 3 months of age: sixteen 5XFAD transgenic and sixteen wild-type mice. Spectral-domain optical coherence tomography, vascular oxygen tension, and blood flow imaging were performed in one eye of each mouse. After imaging, the imaged and fellow retinal tissues were submitted for histological sectioning and amyloid protein analysis, respectively. Protein analysis was also performed on the brain tissues. Results: Retinal physiological changes in venous diameter and blood velocity, arterial and venous oxygen contents, coupled with anatomical alterations in the thickness of retinal cell layers were detected in 5XFAD mice. Moreover, an increase in Aβ42 levels in both the retina and brain tissues was observed in 5XFAD mice. Significant changes in retinal oxygen delivery, metabolism, or extraction fraction were not detected. Based on compiled data from both groups, arterial oxygen content was inversely related to venous blood velocity and nerve fiber/ganglion cell layer thickness. Conclusions: Concurrent alterations in retinal hemodynamic and oxygen metrics, thickness, and tissue Aβ42 protein levels in 5XFAD mice at 3 months of age corresponded to previously reported findings in human AD. Overall, these results suggest that this mouse model can be utilized for studying pathophysiology of AD and evaluating potential therapies.

Artemisinin and Its Derivate Alleviate Pulmonary Hypertension and Vasoconstriction in Rodent Models.

Background Pulmonary arterial hypertension (PAH) is a complex pulmonary vasculature disease characterized by progressive obliteration of small pulmonary arteries and persistent increase in pulmonary vascular resistance, resulting in right heart failure and death if left untreated. Artemisinin (ARS) and its derivatives, which are common antimalarial drugs, have been found to possess a broad range of biological effects. Here, we sought to determine the therapeutic benefit and mechanism of ARS and its derivatives treatment in experimental pulmonary hypertension (PH) models. Methods Isolated perfused/ventilated lung and isometric tension measurements in arteries were performed to test pulmonary vasoconstriction and relaxation. Monocrotaline (MCT) and hypoxia+Su5416 (SuHx) were administered to rats to induce severe PH. Evaluation methods of ARS treatment and its derivatives in animal models include echocardiography, hemodynamics measurement, and histological staining. In vitro, the effect of these drugs on proliferation, viability, and hypoxia-inducible factor 1α (HIF1α) was examined in human pulmonary arterial smooth muscle cells (hPASMCs). Results ARS treatment attenuated pulmonary vasoconstriction induced by high K+ solution or alveolar hypoxia, decreased pulmonary artery (PA) basal vascular tension, improved acetylcholine- (ACh-) induced endothelial-dependent relaxation, increased endothelial nitric oxide (NO) synthase (eNOS) activity and NO levels, and decreased levels of NAD(P)H oxidase subunits (NOX2 and NOX4) expression, NAD(P)H oxidase activity, and reactive oxygen species (ROS) levels of pulmonary arteries (PAs) in MCT-PH rats. NOS inhibitor, L-NAME, abrogated the effects of ARS on PA constriction and relaxation. Furthermore, chronic application of both ARS and its derivative dihydroartemisinin (DHA) attenuated right ventricular systolic pressure (RVSP), Fulton index (right ventricular hypertrophy), and vascular remodeling of PAs in the two rat PH models. In addition, DHA inhibited proliferation and migration of hypoxia-induced PASMCs. Conclusions In conclusion, these results indicate that treatment with ARS or DHA can inhibit PA vasoconstriction, PASMC proliferation and migration, and vascular remodeling, as well as improve PA endothelium-dependent relaxation, and eventually attenuate the development and progression of PH. These effects might be achieved by decreasing NAD(P)H oxidase generated ROS production and increasing eNOS activation to release NO in PAs. ARS and its derivatives might have the potential to be novel drugs for the treatment of PH.

Standardized Rat Coronary Ring Preparation and Real-Time Recording of Dynamic Tension Changes Along Vessel Diameter

As a key event of cardiovascular system diseases, coronary artery disease (CAD) has been widely regarded as the main culprit of atherosclerosis, myocardial infarction, and angina pectoris, which seriously threaten the life and health of people all over the world. However, how to record the dynamic biomechanical characteristics of isolated blood vessels has long puzzled people. Meanwhile, precise positioning and isolation of coronary arteries to measure in vitro dynamic vascular tension changes have become a trend in CAD drug development. The present protocol describes the macroscopic identification and microscopic separation of rat coronary arteries. The contraction and dilation function of the coronary artery ring along the vessel diameter was monitored using the established multi myograph system. The standardized and programmed protocols of coronary ring tension measurement, from sampling to data acquisition, tremendously improve the repeatability of the experimental data, which ensures the authenticity of vascular tension records after physiological, pathological, and drug intervention.

Salvianolic acid A from Danhong Injection induces vasorelaxation by Regulating L-type calcium channel in isolated mouse arteries

Ethnopharmacological relevanceDanhong injection (DHI), which is a Chinese clinical prescription consists of Radix et Rhizoma Salviae Miltiorrhizae (Salvia miltiorrhiza Bge., Labiatae, Danshen in Chinese) and Flos Carthami (Carthamus tinctorius L., Compositae, Honghua in Chinese)(Plant names have been checked with http://www.theplantlist.org on March 1st, 2022), has been mainly used in the clinical therapy of cardiovascular diseases, including hypertension in China for many years. Aim of the studyCardiovascular diseases (CVDs) are the major causes of death all around the world. Due to the various stimulation, a series of vasoconstrictor substances are secreted to regulate the vasoconstriction function and then change blood pressure. The representative substances leading to abnormal vasoconstriction include renin-angiotensin system, endothelin, vasopressin and adrenaline, which act on the corresponding receptors on vascular smooth muscle to constrict blood vessels. Finally, blood pressure increases, followed by a series of cardiovascular diseases, including hypertension. However, little is known about Danhong injection’s specific vasodilating mechanisms and active substances. The aims of the study were to determine the vasodilating substances of Danhong injection and explain its molecular mechanism of vasodilation. Materials and methodsThe effects of DHI and its active components on vascular tension were measured by myograph system in the aortic or mesenteric rings of mice. Based on this, the pharmacodynamic substances were analyzed and effective molecules were found. Combined with multiple types of vascular myograph experiments and network pharmacological analysis, the molecular pathway was preliminarily determined. With molecular biology experiments, it was verified that the relevant mechanisms were closely related to calcium-mediated vasoconstriction in smooth muscle cells. ResultsDHI could relax endothelium-removed aortic rings pre-constricted with PE and 3 possible active vasodilator substances, including salvianolic acid A, salvianolic acid B and danshensu, were screened out by network pharmacology and vascular myograph experiments, among which the effects of salvianolic acid A were dominant. Meanwhile, salvianolic acid A could dilate mesenteric artery in a pressure-dependent manner. Interestingly, salvianolic acid A could still relax the vascular rings under the stimulation of KCl and Bayk8644, two agonists of L-type calcium channel. By contrast, inhibitors of Kir, Kv, Katp and BKCa channels did not block the effect of salvianolic acid A on vasodilation. Salvianolic acid A alleviated Ca2+ transient, referring to changes of intracellular calcium, induced by PE, Bayk8644 and high K+ in the VSMCs. Salvianolic acid A could partially restore the vasodilation function of vascular smooth muscle damaged by AngII and ET-1 induced hypertension situation. ConclusionsOur results indicate that salvianolic acid A is the major vasodilator substance in DHI and the vasorelaxation pharmacology mechanism involved in inhibiting the L-type calcium channel signaling in smooth muscle cell. Hence, there are potential therapeutic effects of taking salvianolic acid A preparation which may be beneficial to protect cardiovascular system and reduce blood pressure.

Favorable effect of rivaroxaban against vascular dysfunction in diabetic mice by inhibiting NLRP3 inflammasome activation.

Cardiovascular disease (CVD) is the leading cause of death in various complications of type 2 diabetes mellitus (T2DM). Rivaroxaban (Xarelto; Bayer), an oral direct factor Xa (FXa) inhibitor, prevents the activation of the coagulation cascade in CVD. Considering its anticoagulant and anti-inflammatory effects, we assessed the hypothesis that rivaroxaban treatment may attenuate the vascular lesion and dysfunction in T2DM mice.C57BL/6, BKS-db/db, BKS-db/+, wild-type (WT), and NLRP3-/- mice were fed with standard chow or high-fat diet (HFD). Biochemical indexes, vascular lesions, and protein expression were evaluated using Western blot analysis, immunofluorescent staining, and RNA interference. Rivaroxaban presented favorable protection of vascular dysfunction in T2DM mice with significantly relieved vascular tension, intima-media thickness, and collagen deposition. Similar improvements in NLR family pyrin domain containing 3 (NLRP3) knockout groups and rivaroxaban pointed to the positive role of rivaroxaban against vascular dysfunction in diabetic mice by ameliorating NLRP3 inflammasome activation. Furthermore, the augmentation of inflammation and cell dysfunction in mice aortic endothelial cells (MAECs) and smooth muscle cells (MOVASs) induced by soluble FXa may be blocked by rivaroxaban via protease-activated receptors (PAR-1, PAR-2), mitogen-activated protein kinase (MAPK), and nuclear factor κ-B (NF-κB) pathway.The data indicate that the development of vascular dysfunction and inflammation in T2DM mice may be blocked by rivaroxaban in vivo and in vitro. Rivaroxaban treatment may also attenuate NLRP3 inflammasome activation via PARs, MAPK, and NF-κB pathway. This study provides mechanistic evidence of rivaroxaban therapies for vascular complications of T2DM.