The antidiabetic drug ipragliflozin induces vasorelaxation of rabbit femoral artery by activating a Kv channel, the SERCA pump, and the PKA signaling pathway.

We explored the vasorelaxant effects of ipragliflozin, a sodium-glucose cotransporter-2 inhibitor, on rabbit femoral arterial rings. Ipragliflozin relaxed phenylephrine-induced pre-contracted rings in a dose-dependent manner. Pre-treatment with the ATP-sensitive K+ channel inhibitor glibenclamide (10 µM), the inwardly rectifying K+ channel inhibitor Ba2+ (50 µM), or the Ca2+-sensitive K+ channel inhibitor paxilline (10 µM) did not influence the vasorelaxant effect. However, the voltage-dependent K+ (Kv) channel inhibitor 4-aminopyridine (3 mM) reduced the vasorelaxant effect. Specifically, the vasorelaxant response to ipragliflozin was significantly attenuated by pretreatment with the Kv7.X channel inhibitors linopirdine (10 µM) and XE991 (10 µM), the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase (SERCA) pump inhibitors thapsigargin (1 µM) and cyclopiazonic acid (10 µM), and the cAMP/protein kinase A (PKA)-associated signaling pathway inhibitors SQ22536 (50 µM) and KT5720 (1 µM). Neither the cGMP/protein kinase G (PKG)-associated signaling pathway nor the endothelium was involved in ipragliflozin-induced vasorelaxation. We conclude that ipragliflozin induced vasorelaxation of rabbit femoral arteries by activating Kv channels (principally the Kv7.X channel), the SERCA pump, and the cAMP/PKA-associated signaling pathway independent of other K+ (ATP-sensitive K+, inwardly rectifying K+, and Ca2+-sensitive K+) channels, cGMP/PKG-associated signaling, and the endothelium.

Local, Downstream, and Systemic Evaluation after Femoral Artery Angioplasty with Kanshas Drug-Coated Balloons In Vitro and in a Healthy Swine Model.

PURPOSE: To evaluate the incidence of distal embolism and local vascular responses after treatment with the Kanshas drug-coated balloon (DCB) in a preclinical model. MATERIALS AND METHODS: A total of 90 femoral arteries from 35 healthy swine were treated with a single-dose (×1) or triple-dose (×3) Kanshas DCB that applies the Unicoat technology with 3.2 µg/mm2 of paclitaxel. An uncoated Kanshas balloon was used as a control. The arterial wall, downstream skeletal muscle, and nontarget organs (kidneys, lungs, lymph nodes, liver, spleen, and heart) were histologically evaluated. For pharmacokinetic evaluation, a total of 40 healthy swine were treated with ×1 Kanshas DCB, and treated vessels were evaluated ex vivo with high-performance liquid chromatography-mass spectrometry. RESULTS: Arteries treated with the Kanshas DCB showed mild proteoglycan deposition accompanied by the loss of smooth muscle cells (SMCs). These changes increased in a dose-dependent manner (medial SMC loss at 28 days in the ×1 vs ×3 groups, in depth, 1 (0.75-1.38) vs 2 (1.63-2.44); P = .0008; in circumference, 0.83 (0.67-1) vs 1.5 (1.19-1.81); P = .0071). No evidence of distal embolization in skeletal muscles (0 of 210 histological sections) and nontarget organs (0 of 345 sections) was observed. The pharmacokinetic evaluation showed high paclitaxel concentration in the treated artery (912 ng/mg, peaking at 3 minutes), which remained detectable at up to 180 days (0.04 ng/mg). CONCLUSIONS: The Kanshas DCB showed a local drug effect in treated arteries up to 180 days with a high concentration of paclitaxel and no histological evidence of distal embolization.

Toxic Metals and Subclinical Atherosclerosis in Carotid, Femoral, and Coronary Vascular Territories: The Aragon Workers Health Study.

OBJECTIVE: Studies evaluating the association of metals with subclinical atherosclerosis are mostly limited to carotid arteries. We assessed individual and joint associations of nonessential metals exposure with subclinical atherosclerosis in 3 vascular territories. Approach and Results: One thousand eight hundred seventy-three Aragon Workers Health Study participants had urinary determinations of inorganic arsenic species, barium, cadmium, chromium, antimony, titanium, uranium, vanadium, and tungsten. Plaque presence in carotid and femoral arteries was determined by ultrasound. Coronary Agatston calcium score ≥1 was determined by computed tomography scan. Median arsenic, barium, cadmium, chromium, antimony, titanium, uranium, vanadium, and tungsten levels were 1.83, 1.98, 0.27, 1.18, 0.05, 9.8, 0.03, 0.66, and 0.23 µg/g creatinine, respectively. The adjusted odds ratio (95% CI) for subclinical atherosclerosis presence in at least one territory was 1.25 (1.03-1.51) for arsenic, 1.67 (1.22-2.29) for cadmium, and 1.26 (1.04-1.52) for titanium. These associations were driven by arsenic and cadmium in carotid, cadmium and titanium in femoral, and titanium in coronary territories and mostly remained after additional adjustment for the other relevant metals. Titanium, cadmium, and antimony also showed positive associations with alternative definitions of increased coronary calcium. Bayesian Kernel Machine Regression analysis simultaneously evaluating metal associations suggested an interaction between arsenic and the joint cadmium-titanium exposure. CONCLUSIONS: Our results support arsenic and cadmium and identify titanium and potentially antimony as atherosclerosis risk factors. Exposure reduction and mitigation interventions of these metals may decrease cardiovascular risk in individuals without clinical disease.

Vascular region-specific changes in arterial tone in rats with type 2 diabetes mellitus: Opposite responses of mesenteric and femoral arteries to acetylcholine and 5-hydroxytryptamine.

AIMS: Type 2 diabetes mellitus (T2DM) ranks in the top 10 causes of mortality worldwide. The key factor of T2DM vascular complications is endothelial dysfunction. It is characterized by the vessels motor activity disruption and endothelium-derived factors imbalance. The blood vessels morphological and molecular heterogeneity greatly affects the changes occurring in T2DM. Therefore, we conducted a comparative study of vascular bed changes occurring in T2DM. MAIN METHODS: Male Wistar rats were fed a high-fat diet for 20 weeks, followed by a single streptozotocin injection (20 mg/kg). T2DM was confirmed with an oral glucose tolerance test. KEY FINDINGS: A dose-dependent contraction study showed an increase in third-order mesenteric arterioles response to serotonin but not to phenylephrine. These vessels also exhibited a decrease in acetylcholine-dependent relaxation and an increase in guanylate cyclase function. At the same time, the femoral arteries showed a tendency for increased acetylcholine-dependent relaxation. The blood plasma analysis revealed low bioavailable nitric oxide and high levels of endothelin-1 and ROS. SIGNIFICANCE: This knowledge, in conjunction with the features of the T2DM course, can allow further targeted approaches development for the prevention and treatment of vascular complications occurring in the disease.

3D modelling of drug-coated balloons for the treatment of calcified superficial femoral arteries.

BACKGROUND/OBJECTIVES: Drug-coated balloon therapy for diseased superficial femoral arteries remains controversial. Despite its clinical relevance, only a few computational studies based on simplistic two-dimensional models have been proposed to investigate this endovascular therapy to date. This work addresses the aforementioned limitation by analyzing the drug transport and kinetics occurring during drug-coated balloon deployment in a three-dimensional geometry. METHODS: An idealized three-dimensional model of a superficial femoral artery presenting with a calcific plaque and treated with a drug-coated balloon was created to perform transient mass transport simulations. To account for the transport of drug (i.e. paclitaxel) released by the device, a diffusion-reaction equation was implemented by describing the drug bound to specific intracellular receptors through a non-linear, reversible reaction. The following features concerning procedural aspects, pathologies and modelling assumptions were investigated: (i) balloon application time (60-180 seconds); (ii) vessel wall composition (healthy vs. calcified wall); (iii) sequential balloon application; and (iv) drug wash-out by the blood stream vs. coating retention, modeled as exponential decay. RESULTS: The balloon inflation time impacted both the free and specifically-bound drug concentrations in the vessel wall. The vessel wall composition highly affected the drug concentrations. In particular, the specifically-bound drug concentration was four orders of magnitude lower in the calcific compared with healthy vessel wall portions, primarily as a result of reduced drug diffusion. The sequential application of two drug-coated balloons led to modest differences (~15%) in drug concentration immediately after inflation, which became negligible within 10 minutes. The retention of the balloon coating increased the drug concentration in the vessel wall fourfold. CONCLUSIONS: The overall findings suggest that paclitaxel kinetics may be affected not only by the geometrical and compositional features of the vessel treated with the drug-coated balloon, but also by balloon design characteristics and procedural aspects that should be carefully considered.

Roles of vascular endothelial and smooth muscle cells in the vasculoprotective effect of insulin in a mouse model of restenosis.

BACKGROUND: Insulin exerts vasculoprotective effects on endothelial cells (ECs) and growth-promoting effects on vascular smooth muscle cells (SMCs) in vitro, and suppresses neointimal growth in vivo. Here we determined the role of ECs and SMCs in the effect of insulin on neointimal growth. METHODS: Mice with transgene CreERT2 under the control of EC-specific Tie2 (Tie2-Cre) or SMC-specific smooth muscle myosin heavy chain promoter/enhancer (SMMHC-Cre) or littermate controls were crossbred with mice carrying a loxP-flanked insulin receptor (IR) gene. After CreERT2-loxP-mediated recombination was induced by tamoxifen injection, mice received insulin pellet or sham (control) implantation, and underwent femoral artery wire injury. Femoral arteries were collected for morphological analysis 28 days after wire injury. RESULTS: Tamoxifen-treated Tie2-Cre+ mice showed lower IR expression in ECs, but not in SMCs, than Tie2-Cre- mice. Insulin treatment reduced neointimal area after arterial injury in Tie2-Cre- mice, but had no effect in Tie2-Cre+ mice. Tamoxifen-treated SMMHC-Cre+ mice showed lower IR expression in SMCs, but not in ECs, than SMMHC-Cre- mice. Insulin treatment reduced neointimal area in SMMHC-Cre- mice, whereas unexpectedly, it failed to inhibit neointima formation in SMMHC-Cre+ mice. CONCLUSION: Insulin action in both ECs and SMCs is required for the "anti-restenotic" effect of insulin in vivo.

Albumin covering maintains endothelial function upon magnetic iron oxide nanoparticles intravenous injection in rats.

Magnetic iron oxide nanoparticles (IONP) present the promising instrument for broad-spectrum of clinical applications, for example, targeted drug delivery. Reactivity of nanoparticles depends on their surface area and material. In the blood plasma IONP are getting covered with an albumin crown, so it was decided to test this shell for biocompatibility. Male Wistar rats were anesthetized and underwent laparotomy. Abdominal aorta was connected to external hemodynamic loop with regulated blood flow. Hind body quarter got step-like blood flow changing from 30 to 150 mmHg and back. This was followed with i.v. injection of IONP, albumin solution or albumin-covered IONP and consequent similar flow changes. Central hemodynamics-heart rate and mean arterial pressure were registered throughout the experiment and no significant changes in these parameters were observed. Hind paw microcirculation level had the same dynamic in all groups under changing blood flow conditions. At the end, venous blood was collected for endothelin-1 and NO evaluation that showed similar changes and no endothelial damage. Mesenteric arteries and femoral artery reactivity were evaluated with wire myography. Mesenteric arteries had the most relaxing function preservation after albumin-covered IONP injection. Given data reveal advantage of albumin-coated IONP so this can be used for further investigations as a vascular-safe vehicle.

Vascular Response of a Polymer-Free Paclitaxel-Coated Stent (Zilver PTX) versus a Polymer-Coated Paclitaxel-Eluting Stent (Eluvia) in Healthy Swine Femoropopliteal Arteries.

PURPOSE: To compare the long-term vascular healing responses of healthy swine iliofemoral arteries treated with a polymer-free paclitaxel-eluting stent (Z-PES, Zilver PTX) or a fluoropolymer-based paclitaxel-eluting stent (FP-PES, Eluvia). MATERIALS AND METHODS: Bilateral iliofemoral arteries in 20 swine were treated with a Z-PES (n = 16) or a FP-PES (n = 24) and were examined histologically at 1, 3, 6, and 12 months. RESULTS: Morphometric analysis revealed larger external and internal elastic lamina, stent expansion, and lumen area in the FP-PES than in the Z-PES at all timepoints. Luminal narrowing was similar in the 2 groups at 1 month; however, greater stenosis was observed in the Z-PES group at 3 months, with significant regression thereafter, resulting in equivalent stenosis at 6 and 12 months. Greater drug effect and less complete vessel healing were found in the FP-PES group at all timepoints, including greater numbers of malapposed struts with excessive fibrin deposition at 1 and 3 months, than in the Z-PES group. Three of 12 FP-PESs from the 6- and 12-month cohorts also showed circumferential medial disruption with peri-strut inflammation, whereas no abnormal findings were observed in contralateral Z-PESs. CONCLUSIONS: Prolonged paclitaxel release with the presence of a permanent polymer may contribute to the differential vascular responses seen for the Z-PES and FP-PES groups, including medial layer disruption and aneurysmal vessel degeneration that was sometimes observed in the FP-PES group. These distinct features should be confirmed by pathology and in vivo imaging of human superficial femoral arteries to determine their clinical significance.

Different Responses of Arterial Stiffness between the Aorta and the Iliofemoral Artery during the Administration of Phentolamine and Atenolol in Rabbits.

AIM: The mechanism underlying the stiffness of the aorta and iliofemoral artery that is required to maintain blood pressure (BP) is unclear. A new stiffness index of the aorta (aBeta) and iliac-femoral arteries (ifBeta) was defined by applying the cardio-ankle vascular index (CAVI). We compared changes in stiffness of the two arteries in response to reduced BP, due to the non-selective α adrenergic blocker phentolamine and the ß1 adrenergic blocker atenolol, in rabbits. METHODS: Pressure waves at the origin (oA) and distal ends of the aorta (dA) and the distal end of the left femoral artery (fA) were recorded simultaneously using three pressure sensors in 25 anesthetized rabbits. Phentolamine (50 µg/kg/min) and atenolol (10 mg/kg/min) were infused for 2 min. The pulse wave velocity (PWV) in each artery was determined; aBeta, ifBeta, and whole Beta (aifBeta) were calculated by the following formula; Beta=2ρ/PP×ln(SBP/DBP)×PWV2 (ρ: blood density; SBP, SBP, and PP: systolic, diastolic, and pulse pressures, respectively). RESULTS: SBP and DBP at oA, dA, and fA decreased by the administration of phentolamine and atenolol, with and without decreased total peripheral vascular resistance. After phentramine infusion, cardiac output (CO), aBeta, and aifBeta increased, while ifBeta decreased. After infusion of atenolol, CO decreased, while aBeta, ifBeta, and aifBeta remained unchanged. CONCLUSION: The contradictory reactions of aBeta and ifBeta to phentolamine suggest that the stiffness of the aorta and ilio-femoral artery is regulated separately during decreased BP induced by phentolamine, but not by atenolol.

Aldosterone Induces Vasoconstriction in Individuals with Type 2 Diabetes: Effect of Acute Antioxidant Administration.

CONTEXT: Individuals with type 2 diabetes have an increased risk of endothelial dysfunction and cardiovascular disease. Plasma aldosterone could contribute by reactive oxygen species-dependent mechanisms by inducing a shift in the balance between a vasoconstrictor and vasodilator response to aldosterone. OBJECTIVE: We aimed to investigate the acute vascular effects of aldosterone in individuals with type 2 diabetes compared with healthy controls and if infusion of an antioxidant (n-acetylcysteine [NAC]) would alter the vascular response. METHODS: In a case-control design, 12 participants with type 2 diabetes and 14 healthy controls, recruited from the general community, were studied. Leg hemodynamics were measured before and during aldosterone infusion (0.2 and 5 ng min-1 [L leg volume]-1) for 10 minutes into the femoral artery with and without coinfusion of NAC (125 mg kg-1 hour-1 followed by 25 mg kg-1 hour-1). Leg blood flow and arterial blood pressure was measured, and femoral arterial and venous blood samples were collected. RESULTS: Compared with the control group, leg blood flow and vascular conductance decreased during infusion of aldosterone at the high dose in individuals with type 2 diabetes, whereas coinfusion of NAC attenuated this response. Plasma aldosterone increased in both groups during aldosterone infusion and there was no difference between groups at baseline or during the infusions. CONCLUSION: These results suggests that type 2 diabetes is associated with a vasoconstrictor response to physiological levels of infused aldosterone and that the antioxidant NAC diminishes this response.

Imatinib improves insulin resistance and inhibits injury-induced neointimal hyperplasia in high fat diet-fed mice.

Imatinib, a PDGF receptor tyrosine kinase inhibitor, has been shown to suppress intimal hyperplasia in different animal models under normal metabolic milieu, diabetic, and/or hypercholesterolemic conditions. However, the impact of imatinib treatment on injury-induced neointimal hyperplasia has not yet been investigated in the setting of insulin resistance without frank diabetes. Using a mouse model of high fat diet (HFD)-induced insulin resistance and guidewire-induced arterial injury, the present study demonstrates that intraperitoneal administration of imatinib (25 mg/kg/day) for ~3 weeks resulted in a marked attenuation of neointimal hyperplasia (intima/media ratio) by ~78% (n = 6-9 per group; P < 0.05). Imatinib treatment also led to significant improvements in key metabolic parameters. In particular, imatinib improved insulin resistance and glucose tolerance, as revealed by complete inhibition of HFD-induced increase in HOMA-IR index and AUCIPGTT, respectively. In addition, imatinib treatment led to diminutions in HFD-induced increases in plasma total cholesterol and triglycerides by ~73% and ~59%, respectively. Furthermore, imatinib decreased HFD-induced increase in visceral fat accumulation by ~51% (as determined by epididymal white adipose tissue weight). Importantly, imatinib treatment in HFD-fed mice enhanced plasma levels of high-molecular-weight adiponectin by ~2-fold without affecting total adiponectin. However, there were no significant changes in mean arterial pressure in insulin-resistant state or after imatinib exposure, as measured by tail-cuff method. Together, the present findings suggest that targeting PDGF receptor tyrosine kinase using imatinib may provide a realistic treatment option to prevent injury-induced neointimal hyperplasia and diet-induced insulin resistance in obesity.

Differential Contractile Reactivity to Nucleotides in Femoral Arteries of OLETF and LETO Rats.

Extracellular nucleotides play an important role in the regulation of vascular function, and an abnormal vascular function is an important participant in the development and progression of diabetic vascular complications. The purpose of this study was to determine whether contractile responses induced by extracellular nucleotides and a dinucleotide, uridine adenosine tetraphosphate (Up4A), in femoral arteries would be altered at the chronic stage of type 2 diabetes. We determined the changes in contractile reactivity induced by ATP, uridine triphosphate (UTP), uridine diphosphate (UDP), and Up4A in the femoral arteries of Otsuka Long-Evans Tokushima Fatty (OLETF) rats (aged male type 2 diabetic rats) and, Long-Evans Tokushima Otsuka (LETO) rats (controls for OLETF rats). ATP-induced contractions were greater in OLETF rats than in LETO rats. UTP-induced contractions were lower in OLETF rats than in LETO rats. UDP- and Up4A-induced contractions were similar between OLETF and LETO rats. The femoral artery contractile changes induced by the extracellular nucleotides and dinucleotide were similar when nitric oxide synthase was inhibited. These results suggest that the extent of femoral artery contractile reactivity to nucleotides/dinucleotides differs during long-term duration of type 2 diabetes.

Vascular dysfunction and oxidative stress caused by acute formaldehyde exposure in female adults.

Formaldehyde (FA) is a common, volatile organic compound used in organic preservation with known health effects of eye, nose, and throat irritation linked to oxidative stress and inflammation. Indeed, long-term FA exposure may provoke skin disorders, cancer, and cardiovascular disease. However, the effects of short-term FA exposure on the vasculature have yet to be investigated. We sought to investigate the impact of an acute FA exposure on 1) macrovascular function in the arm (brachial artery flow-mediated dilation, FMD), 2) microvascular function in the arm (brachial artery reactive hyperemia, RH) and leg (common femoral artery, supine passive limb movement, PLM), and 3) circulating markers of oxidative stress (xanthine oxidase, XO; protein carbonyl, PC; and malondialdehyde, MDA) and inflammation (C-reactive protein, CRP). Ten (n = 10) healthy females (23 ± 1 yr) were studied before and immediately after a 90-min FA exposure [(FA): 197 ± 79 ppb] in cadaver dissection laboratories. Brachial artery FMD% decreased following FA exposure (Pre-FA Exp: 9.41 ± 4.21%, Post-FA Exp: 6.74 ± 2.57%; P = 0.043), and FMD/shear decreased following FA exposure (Pre-FA Exp: 0.13 ± 0.07 AU, Post-FA Exp: 0.07 ± 0.03 AU; P = 0.016). The area under the curve for brachial artery RH (Pre-FA Exp: 481 ± 191 ml, Post-FA Exp: 499 ± 165 ml) and common femoral artery PLM (Pre-FA Exp: 139 ± 95 ml, Post-FA Exp: 129 ± 64 ml) were unchanged by FA exposure (P > 0.05). Circulating MDA increased (Pre-FA Exp: 4.8 ± 1.3 µM, Post-FA Exp: 6.3 ± 2.2 µM; P = 0.047) while XO, PC, and CRP were unchanged by FA exposure (P > 0.05). These initial data suggest a short FA exposure can adversely alter vascular function and oxidative stress, influencing cardiovascular health.NEW & NOTEWORTHY This study was the first to investigate the implications of acute formaldehyde (FA) exposure on adult female vascular function in the arms and legs. The main findings of this study were a decrease in conduit vessel function without any alteration to microvascular function following a 90-min FA exposure. Additionally, the oxidative stress marker malondialdehyde increased after FA exposure. Taken together, these results suggest acute FA exposure have deleterious implications for the vasculature and redox balance.Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/formaldehyde-exposure-decreases-vascular-function/.

High concentration of uric acid failed to affect endothelial function of small mesenteric arteries, femoral arteries and aortas from aged Wistar-Kyoto rats.

It is known that a high level of uric acid (UA) in plasma, hyperuricemia (HU), is associated with the increased risk of cardiovascular diseases (CVDs). Endothelial damage has been suggested as a potential mechanism involved in HU-induced CVDs, especially in patients with the accumulation of other cardiovascular risk factors. However, the role of UA in the pathogenesis of endothelial dysfunction is still a matter of debate. It is unclear whether UA is a causative risk factor in endothelial dysfunction, an inert marker or an endothelium-protective molecule with respect to its antioxidant properties. Of note, only a few studies have been conducted to investigate the effect of UA on vascular endothelium-dependent relaxation. Therefore, we have studied the acute in vitro effects of high UA concentrations on the endothelial function of arteries isolated from aged rats. Experiments were performed in small mesenteric arteries (SMAs), femoral arteries and thoracic aortas isolated from 68-week-old and 57-week-old male Wistar-Kyoto rats. Vascular reactivity was investigated in isometric conditions using the wire myograph and organ chamber. Acetylcholine (ACh) was used to investigate endothelium-dependent vasorelaxation. Then, UA was added to the myograph or organ chamber at 600 µmol/l (arteries from 68-week-old rats) or 1200 µmol/l (arteries from 57-week-old rats) and incubated for 1 h, and this was followed by determining the ACh concentration-response curve. UA had no significant effect on ACh-induced vasorelaxation and pD2 values in all investigated groups. Likewise, no significant differences in noradrenaline- (SMAs), serotonin- (femoral arteries) and phenylephrine-induced (aortas) vasoconstriction were observed after UA pre-incubation. In conclusion, high concentrations of UA administered acutely failed to affect endothelial function and did not provoke endothelial dysfunction in resistant mesenteric arteries, medium-sized and large arteries from aged rats.

Resveratrol Inhibits Neointimal Growth after Arterial Injury in High-Fat-Fed Rodents: The Roles of SIRT1 and AMPK.

We have shown that both insulin and resveratrol (RSV) decrease neointimal hyperplasia in chow-fed rodents via mechanisms that are in part overlapping and involve the activation of endothelial nitric oxide synthase (eNOS). However, this vasculoprotective effect of insulin is abolished in high-fat-fed insulin-resistant rats. Since RSV, in addition to increasing insulin sensitivity, can activate eNOS via pathways that are independent of insulin signaling, such as the activation of sirtuin 1 (SIRT1) and AMP-activated kinase (AMPK), we speculated that unlike insulin, the vasculoprotective effect of RSV would be retained in high-fat-fed rats. We found that high-fat feeding decreased insulin sensitivity and increased neointimal area and that RSV improved insulin sensitivity (p < 0.05) and decreased neointimal area in high-fat-fed rats (p < 0.05). We investigated the role of SIRT1 in the effect of RSV using two genetic mouse models. We found that RSV decreased neointimal area in high-fat-fed wild-type mice (p < 0.05), an effect that was retained in mice with catalytically inactive SIRT1 (p < 0.05) and in heterozygous SIRT1-null mice. In contrast, the effect of RSV was abolished in AMKPα2-null mice. Thus, RSV decreased neointimal hyperplasia after arterial injury in both high-fat-fed rats and mice, an effect likely not mediated by SIRT1 but by AMPKα2.

Effect and mechanism of prophylactic use of tadalafil during pregnancy on l-NAME-induced preeclampsia-like rats.

INTRODUCTION: Preeclampsia (PE) is a serious maternal inflammatory disease with endothelial cell dysfunction, and there is a lack of effective treatment and prevention. Tadalafil is considered to be a promising drug for PE. This study aimed to determine whether and how tadalafil use during early pregnancy alleviates PE induced by N-nitro-l-arginine-methyl-ester (l-NAME), an antagonist of nitric oxide synthase, in rats. METHODS: Twenty-eight Sprague-Dawley (SD) rats were randomly divided into 4 equal groups on gestational day 0 (GD0): a pregnant control group, an l-NAME-treated PE group and two prophylactic low-dose and high-dose tadalafil groups. Blood pressure was measured on GD0, 5, 10, 15 and 20. Proteinuria was assessed on GD0 and 18. Femoral artery ultrasound was performed on GD19. Tissue sampling was performed on GD20. The perinatal outcomes, placenta and kidney tissue morphology, and endothelial and inflammatory markers were examined. RESULTS: Prophylactic administration of low and high doses of tadalafil improved l-NAME induced hypertension, proteinuria, maternal weight loss during pregnancy, fetal growth restriction and flow-mediated dilatation, balanced endothelial-relative factors, and alleviated inflammation activation in placenta and kidney tissue. What's more, in some results, the HT group performed better than the LT group. DISCUSSION: Our results indicate that prophylactic use of tadalafil in l-NAME-induced PE-like rat models alleviates PE symptoms, promotes fetal growth, protects endothelial function and reduces inflammation, suggesting that tadalafil may be a potential drug for the prevention of PE.

Effects of Inhibition of Nitric Oxide Synthase on Muscular Arteries During Exercise: Nitric Oxide Does Not Contribute to Vasodilation During Exercise or in Recovery.

Background Basal release of nitric oxide (NO) from the vascular endothelium regulates the tone of muscular arteries and resistance vasculature. Effects of NO on muscular arteries could be particularly important during exercise when shear stress may stimulate increased NO synthesis. Methods and Results We investigated acute effects of NO synthase inhibition on exercise hemodynamics using NG-monomethyl-l-arginine (l-NMMA), a nonselective NO synthase -inhibitor. Healthy volunteers (n=10, 5 female, 19-33 years) participated in a 2-phase randomized crossover study, receiving l-NMMA (6 mg/kg, iv over 5 minutes) or placebo before bicycle exercise (25-150 W for 12 minutes). Blood pressure, cardiac output (measured by dilution of soluble and inert tracers) and femoral artery diameter were measured before, during, and after exercise. At rest, l-NMMA reduced heart rate (by 16.2±4.3 bpm relative to placebo, P<0.01), increased peripheral vascular resistance (by 7.0±1.4 mmHg per L/min, P<0.001), mean arterial blood pressure (by 8.9±3.5 mmHg, P<0.05), and blunted an increase in femoral artery diameter that occurred immediately before exercise (change in diameter: 0.14±0.04 versus 0.32±0.06 mm after l-NMMA and placebo, P<0.01). During/after exercise l-NMMA had no significant effect on peripheral resistance, cardiac output, or on femoral artery diameter. Conclusions These results suggest that NO plays little role in modulating muscular artery function during exercise but that it may mediate changes in muscular artery tone immediately before exercise.

Effect of perivascular low dose ethanol on rat femoral vessels: Preliminary study.

Vasospasm is one of the important causes of morbidity in free flap and replantation surgery. In secondary Raynaud's phenomenon, nearly half of the patients experience digital ulceration, pain and loss of function at least once in their lifetime. The aim of this study is to investigate the vasodilation effect of ethanol-mediated chemical denervation on peripheral vessels by topical administration. In this study, 27 Wistar albino male rats weighing 250-300 grams were used. The rats were randomly divided into three groups: saline (group S, n = 8), lidocaine (group L, n = 9) and 96% ethanol (group E, n = 9). According to group, 0.1 mL saline, 0.1 mL lidocaine and 0.1 mL ethanol were applied around the rat femoral neurovascular bundle. After the application, on the 0th day and 3th weeks, femoral artery and vein diameters were measured. After 3. weeks, histopathological samples from femoral artery, vein and nerve were evaluated. On the 0th day, the mean diameter of the femoral artery and vein was similar in group E and L and higher than group S. After three weeks, the vasodilatation effect of ethanol was increased in group E. In Group L and S, the vasodilatation effect was lost. Histopathological examination showed that ethanol significantly caused perivascular inflammation and nerve degeneration compared to other agents and did not cause endothelial damage. Vasodilatation obtained by ethanol is a rapid onset and long-lasting effect. It is also inexpensive and effective for peripheral vasodilatation.

A thrombolytic therapy using diagnostic ultrasound combined with RGDS-targeted microbubbles and urokinase in a rabbit model.

This study aimed to explore thrombolysis therapy based on ultrasound combined with urokinase and Arg-Gly-Asp sequence (RGDS)-targeted microbubbles by evaluating the histological changes in a thrombotic rabbit model. Forty-two New Zealand rabbits featuring platelet-rich thrombi in the femoral artery were randomized to (n = 6/group): ultrasound alone (US); urokinase alone (UK); ultrasound plus non-targeted microbubbles (US + M); ultrasound plus RGDS-targeted microbubbles (US + R); RGDS-targeted microbubbles plus urokinase (R + UK); ultrasound, non-targeted microbubbles and urokinase (US + M + UK); and ultrasound, RGDS-targeted microbubbles and urokinase (US + R + UK) groups. Diagnostic ultrasound was used transcutaneously over the thrombus for 30 min. We evaluated the thrombolytic effect based on ultrasound thrombi detection, blood flow, and histological observations. Among all study groups, complete recanalization was achieved in the US + R + UK group. Hematoxylin and eosin staining showed that the thrombi were completely dissolved. Scanning electron microscopy examination demonstrated that the fiber network structure of the thrombi was damaged. Transmission electron microscopy showed that the thrombus was decomposed into high electron-dense particles. Histology for von Willebrand factor and tissue factor were both negative in the US + R + UK group. This study revealed that a thrombolytic therapy consisting of diagnostic ultrasound together with RGDS-targeted and urokinase coupled microbubbles.

Kv1.3 blockade inhibits proliferation of vascular smooth muscle cells in vitro and intimal hyperplasia in vivo.

The modulation of voltage-gated K+ (Kv) channels, involved in cell proliferation, arises as a potential therapeutic approach for the prevention of intimal hyperplasia present in in-stent restenosis (ISR) and allograft vasculopathy (AV). We studied the effect of PAP-1, a selective blocker of Kv1.3 channels, on development of intimal hyperplasia in vitro and in vivo in 2 porcine models of vascular injury. In vitro phenotypic modulation of VSMCs was associated to an increased functional expression of Kv1.3 channels, and only selective Kv1.3 channel blockers were able to inhibit porcine VSMC proliferation. The therapeutic potential of PAP-1 was then evaluated in vivo in swine models of ISR and AV. At 15-days follow-up, morphometric analysis demonstrated a substantial reduction of luminal stenosis in the allografts treated with PAP-1 (autograft 2.72 ± 1.79 vs allograft 10.32 ± 1.92 vs allograft + polymer 13.54 ± 8.59 vs allograft + polymer + PAP-1 3.06 ± 1.08 % of luminal stenosis; P = 0.006) in the swine model of femoral artery transplant. In the pig model of coronary ISR, using a prototype of PAP-1-eluting stent, no differences were observed regarding % of stenosis compared to control stents (31 ± 13 % vs 37 ± 18%, respectively; P = 0.372) at 28-days follow-up. PAP-1 treatment was safe and did not impair vascular healing in terms of delayed endothelialization, inflammation or thrombosis. However, an incomplete release of PAP-1 from stents was documented. We conclude that the use of selective Kv1.3 blockers represents a promising therapeutic approach for the prevention of intimal hyperplasia in AV, although further studies to improve their delivery method are needed to elucidate its potential in ISR.