Xanthine Oxidase Activation Modulates the Endothelial (Vascular) Dysfunction Related to HgCl<Subscript>2</Subscript> Exposure Plus Myocardial Infarction in Rats

Heavy metal exposure is associated with cardiovascular diseases such as myocardial infarction (MI). Vascular dysfunction is related to both the causes and the consequences of MI. We investigated whether chronic exposure to low doses of mercury chloride (HgCl₂) worsens MI-induced endothelial dysfunction 7 days after MI. Male Wistar rats were divided into four groups: Control (vehicle), HgCl₂ (4 weeks of exposure), surgically induced MI and combined HgCl₂-MI. Morphological and hemodynamic measurements were used to characterize the MI model 7 days after the insult. Vascular reactivity was evaluated in aortic rings. Chronic HgCl₂ exposure did not cause more heart injury than MI alone in terms of the morphological or hemodynamic parameters. Vascular reactivity increased in all groups, but the combination of HgCl₂-MI increased the vasorelaxation induced by ACh compared with the HgCl₂ and MI groups. Results showed reduced endothelial nitric oxide synthase (eNOS) protein expression in the MI group; increased iNOS activity in the HgCl₂-MI group, although without enough magnitude to reverse the reduction in NO bioavailability; and increased phenylephrine response in the HgCl₂-MI group due to an increase in ROS production, notably via xanthine oxidase (XO). Results suggest that the combination of 1 month pre-exposure of HgCl₂ before MI changed the endothelial generation of oxidative stress induced by mercury exposure from NADPH oxidase pathway to XO (xanthine oxidase)-dependent ROS production.     

The P2Y<Subscript>1</Subscript> receptor antagonist MRS2500 prevents carotid artery thrombosis in cynomolgus monkeys

Adenosine diphosphate directly induces platelet aggregation via the G-protein coupled P2Y₁ and P2Y₁₂ receptors. P2Y₁₂, but not P2Y₁, receptor antagonists are available in the clinic. The relevance of the P2Y₁ receptor as an antiplatelet target has been studied in rodents, but not in higher species. We therefore examined effects of the pharmacological blockade of the P2Y₁ receptor with its selective antagonist MRS2500 in monkey models of electrolytic-mediated arterial thrombosis (ECAT) and kidney bleeding time (KBT). Abciximab, a GPIIb-IIIa antagonist, and cangrelor, a P2Y₁₂ antagonist, were utilized to validate these monkey models. Compounds were given IV at 15–60 min before thrombosis initiation in anesthetized monkeys. Scanning electron microscopy showed the luminal surface of thrombotic artery covered with platelet aggregates and fibrin network. Administration of abciximab at 0.25 and 0.7 mg/kg IV significantly reduced thrombus weight by 71 ± 1 and 100 ± 0 %, and increased KBT by 10.0 ± 0.1- and 10.1 ± 0-fold, respectively (n = 3/dose). Likewise, cangrelor at 0.6 and 2 mg/kg/h IV significantly reduced thrombus weight significantly by 72 ± 9 % and 100 ± 0 % and increased KBT by 2.1 ± 0.1- and 9.8 ± 0.2-fold, respectively (n = 3/dose). MRS2500 [mg/kg + mg/kg/h IV] at 0.09 + 0.14 and 0.45 + 0.68 significantly reduced thrombus weight by 57 ± 1 % and 88 ± 1 % and increased KBT by 2.1 ± 0.3- and 4.9 ± 0.6-fold, respectively (n = 4/dose). In summary, MRS2500 prevented occlusive arterial thrombosis at a dose that moderately prolonged KBT, indicating a role of P2Y₁ receptors in arterial thrombosis and hemostasis in monkeys. Thus P2Y₁ receptor antagonism provides a suitable target for drug discovery.     

Effects of fish oil and curcumin supplementation on cerebrovascular function in older adults: A randomized controlled trial

Background and aimsChronic conditions such as obesity, which contribute to endothelial dysfunction in older adults, can cause impairments in cerebrovascular perfusion, which is associated with accelerated cognitive decline. Supplementing the diet with bioactive nutrients that can enhance endothelial function, such as fish oil or curcumin, may help to counteract cerebrovascular dysfunction.Methods and resultsA 16-week double-blind, randomized placebo-controlled trial was undertaken in 152 older sedentary overweight/obese adults (50–80 years, body mass index: 25–40 kg/m²) to investigate effects of fish oil (2000 mg docosahexaenoic acid + 400 mg eicosapentaenoic acid/day), curcumin (160 mg/day) or a combination of both on cerebrovascular function (measured by Transcranial Doppler ultrasound), systemic vascular function (blood pressure, heart rate and arterial compliance) and cardiometabolic (fasting glucose and blood lipids) and inflammatory (C-reactive protein) biomarkers. The primary outcome, cerebrovascular responsiveness to hypercapnia, was not affected by the interventions. However, cerebral artery stiffness was significantly reduced in males following fish oil supplementation (P = 0.007). Furthermore, fish oil reduced heart rate (P = 0.038) and serum triglycerides (P = 0.006) and increased HDL cholesterol (P = 0.002). Curcumin did not significantly affect these outcomes either alone or in combination with fish oil.ConclusionRegular supplementation with fish oil but not curcumin improved biomarkers of cardiovascular and cerebrovascular function. The combined supplementation did not result in additional benefits. Further studies are warranted to identify an efficacious curcumin dose and to characterize (in terms of sex, BMI, cardiovascular and metabolic risk factors) populations whose cerebrovascular and cognitive functions might benefit from either intervention.Clinical trial registrationACTRN12616000732482p.     

Relationships between maximal oxygen uptake and endothelial function in healthy male adults: a preliminary study

Aerobic capacity, as indicated by maximal oxygen uptake (VO₂ max) has an important role in contrasting the traditional cardiovascular risk factors and preventing cardiovascular morbidity and mortality. It is known that endothelial function, measured as flow-mediated dilation (FMD) of the brachial artery, is strictly linked to atherogenesis and cardiovascular risk. However, the relationship between VO₂ max and FMD has not been fully investigated especially in healthy non-obese subjects. This preliminary study cross-sectionally investigated the relationship between VO₂ max and FMD in 22 non-obese, healthy sedentary male subjects. Dividing the cohort in two subgroups of 11 subjects each according to the median value of VO₂ max, the FMD was significantly lower in the subgroup with lower VO₂ max (mean ± sem: 7.1 ± 0.7 vs. 9.5 ± 0.8 %; P = 0.035). Absolute VO₂ max (mL min^?1) was significantly and independently correlated with body fat mass (r = ?0.50; P = 0.018) and with FMD (r = 0.44; P = 0.039). This preliminary study suggests that maximal oxygen uptake is independently correlated with endothelial function in healthy non-obese adults. These results are also in agreement with the possibility that improving maximal oxygen uptake may have a favorable effect on endothelial function and vice versa.     

Involvement of the renin–angiotensin system in the development of vascular damage in a rat model of arthritis: Effect of angiotensin receptor blockers

Objective

To explore the involvement of the renin–angiotensin system (RAS) in the development of vascular damage in adjuvant‐induced arthritis (AIA) in rats.

Methods

Angiotensin II (Ang II; 0.25 or 1.0 mg/kg/day) was infused in control rats and rats with AIA for 21 days, and the impact of systemic inflammation on Ang II–induced hypertension, endothelial dysfunction, and vascular hypertrophy was evaluated. Expression of angiotensin II type 1 receptor (AT₁R) and angiotensin‐converting enzyme (ACE) in the aortas of rats with AIA were examined by real‐time polymerase chain reaction (PCR) and Western blot analyses. Losartan (3 mg/kg/day) or irbesartan (5 mg/kg/day), both of which are AT₁R blockers, was administered orally to rats with AIA for 21 days. In situ superoxide production in aortas was assessed according to the fluorogenic oxidation of dihydroethidium to ethidium. The expression and activity of NAD(P)H oxidases in aortas were examined by real‐time PCR analysis and lucigenin chemiluminescence assay. Endothelial function in rats with AIA treated in vivo or ex vivo with AT₁R blockers was also determined.

Results

The Ang II–induced hypertensive response, endothelial dysfunction, and vascular hypertrophy were exacerbated in rats with AIA. Expression of AT₁R and ACE was increased in the aortas of rats with AIA. Both losartan and irbesartan decreased the levels of superoxide and the expression and activity NAD(P)H oxidases in the aortas of rats with AIA. The endothelial dysfunction in AIA was improved by the in vivo or ex vivo treatment with AT₁R blockers.

Conclusion

The locally activated RAS is involved in the increased vascular oxidative stress and endothelial dysfunction in AIA. Our findings have important implications for clinical approaches to the reduction of cardiovascular risk in patients with rheumatoid arthritis.

     

Insulin-like growth factor I (IGF-1) supplementation prevents diabetesinduced alterations in coenzymes Q<Subscript>9</Subscript> and Q<Subscript>10</Subscript>

Diabetes, which causes enhanced oxidative stress, is a multifactorial disease that leads to deleterious effects in many organ systems within the body. Ubiquinones (coenzyme Q₉ and Q₁₀) are amphipathic molecular components of the electron transport chain that function also as endogenous antioxidants and attenuate the diabetes-induced decreases in antioxidant defense mechanisms. Insulin-like growth factor 1 (IGF-1) is considered to be an “essential surviving factor”, the level and function of which are compromised in diabetes. This study investigated the impact of IGF-1 supplementation on ubiquinone levels in a rat model of type I diabetes. Adult male Sprague-Dawley rats were divided into four groups: control, control plus IGF-1, diabetic and diabetic plus IGF-1. Diabetic animals received a single intravenous injection of streptozotocin (STZ, 55 mg/kg). IGF-1 supplementation groups received a daily intraperitoneal dose of 3 mg IGF-1 per kilogram body weight for 7 weeks. Coenzyme Q₉ and Q₁₀ levels were assessed by ultraviolet detection on high pressure liquid chromatography. STZ caused a significant reduction in body weight and an elevation in blood glucose level, which were not prevented by IGF-1 supplementation. In addition Q₉ and Q₁₀ levels in diabetic liver were significantly elevated. IGF-1 supplementation prevented liver alterations in Q₁₀ but not Q₉ levels. Q₉ and Q₁₀ levels in diabetic kidney were significantly depressed, and these deleterious effects were abolished by IGF-1 treatment. These data suggest that IGF-1 antagonizes the diabetes-induced alterations in endogenous antioxidants including coenzyme Q₁₀, and hence may have a therapeutic role in diabetes. Received: 28 March 2002 / Accepted in revised form: 5 December 2002 Correspondence to J. Ren     

Folate supplementation during pregnancy improves offspring cardiovascular dysfunction induced by protein restriction

Dietary protein restriction in the rat compromises the maternal cardiovascular adaptations to pregnancy and leads to raised blood pressure and endothelial dysfunction in the offspring. In this study we have hypothesized that dietary folate supplementation of the low-protein diet will improve maternal vascular function and also restore offspring cardiovascular function. Pregnant Wistar rats were fed either a control (18% casein) or protein-restricted (9% casein) diet +/-5 mg/kg folate supplement. Function of isolated maternal uterine artery and small mesenteric arteries from adult male offspring was assessed, systolic blood pressure recorded, and offspring thoracic aorta levels of endothelial nitric oxide (NO) synthase mRNA measured. In the uterine artery of late pregnancy dams, vasodilatation to vascular endothelial growth factor was attenuated in the protein-restricted group but restored with folate supplementation, as was isoprenaline-induced vasodilatation (P<0.05). In male offspring, protein restriction during pregnancy led to raised systolic blood pressure (P<0.01), impaired acetylcholine-induced vasodilatation (P<0.01), and reduced levels of endothelial NO synthase mRNA (P<0.05). Maternal folate supplementation during pregnancy prevented this elevated systolic blood pressure associated with a protein restriction diet. With folate supplementation, endothelium-dependent vasodilatation and endothelial NO synthase mRNA levels were not significantly different from either the control or protein-restricted groups. Maternal folate supplementation of the control diet had no effect on blood pressure or vasodilatation. This study supports the hypothesis that folate status in pregnancy can influence fetal development and, thus, the risks of cardiovascular disease in the next generation. The concept of developmental origins of adult disease focuses predominately on fetal life but must also include a role for maternal cardiovascular function.     

Effect of vitamin D supplementation on reduction of cardiometabolic risk in patients with type 2 diabetes mellitus and dyslipidemia

Endothelial progenitor cells (EPCs) participate in endothelial regeneration. Previous studies link vitamin D deficiency, inflammatory cytokines, and cardiovascular disease (CVD) risk. This study evaluates the impact of vitamin D supplementation on EPCs, inflammatory markers, and glycemia in type 2 diabetes. This is prospective open-label randomized controlled study. Sixty-five patients with type 2 diabetes, dyslipidemia, HbA_1c below 9%, and vitamin D deficiency (below 30 ng/ml) attending the outpatient clinic between April and December 2015 were randomized to active vitamin D (60,000 IU of vitamin D orally once a week for 8 weeks, followed by once a month for 4 months) or control for 6 months. Data was analyzed with STATA 14. Demographics include median age 54 (range 48.5–60) years, median duration of diabetes 7 (4–12.5) years, mean BMI 26.86 ± 3.8 kg/m², mean HbA_1c 7.22±0.8%, and median vitamin D 13.42 (range 10.24–17.23) ng/ml; 50% were men. Vitamin D supplementation increased vitamin D levels in the active group compared to control (p < 0.01). EPCs decreased in both groups from baseline. There was no difference in change in EPCs, hsCRP, IL-6, IL-10, TNF-α, and HbA_1c or insulin resistance (HOMA-IR) between the active- and control-groups at the end of the study. Vitamin D supplementation did not alter EPCs or inflammatory markers, or improve glycemic control at the dose and duration investigated. Further studies are needed to study the long-term effects on markers of endothelial repair.     

Lp-PLA<Subscript>2</Subscript> as a Marker of Cardiovascular Diseases

Inflammation lies at the base of endothelial dysfunction, eventually leading to plaque formation. The degree of inflammation defines the “vulnerability” of plaque to rupture. Numerous strategies have been adopted to identify and eventually treat high-risk vulnerable plaque. Lipoprotein-associated phospholipase A₂ (Lp-PLA₂) has emerged as one such candidate marker of inflammation that may play a direct role in the formation of rupture-prone plaque. Epidemiologic studies have clearly demonstrated the prognostic ability of increased Lp-PLA₂ levels and their association with increased risk of future coronary and cerebrovascular events. Moreover, Lp-PLA₂ might have similar predictive power for both incident coronary heart disease in initially healthy individuals as well as for recurrent events in those with clinically manifest atherosclerosis. The latest evidence has also suggested its incremental value for risk determination over the well-established traditional risk factors and biomarkers in patients with congestive heart failure. These data support an integral role of Lp-PLA₂ activity in lipid peroxidation and cardiovascular risk assessment. This review summarizes the current body of evidence supporting the clinical utility of Lp-PLA₂ and its future applications in cardiovascular medicine.     

Cardiovascular Toxicity of Different Sizes Amorphous Silica Nanoparticles in Rats After Intratracheal Instillation

The purpose of this work was to investigate the cardiovascular toxicity of different sizes and different dosages of silica nanoparticles in Wistar rats. The three silica nanoparticles (30, 60, and 90 nm) and one fine silica particles (600 nm) at three doses of 2, 5, and 10 (mg/Kg bw) were used in the present experiment. After intratracheal instillation for a total of 16 times, concentration of Si in hearts and serum was measured by inductively coupled plasma optical emission spectrometer. The hematology parameters were analyzed by an automated hematology analyzer, and the inflammatory reaction, oxidative stress, endothelial dysfunction, and the myocardial enzymes in serum were measured by kits. Our results showed intratracheal-instilled silica nanoparticles could pass through the alveolar-capillary barrier into systemic circulation. Concentration of Si in the heart and serum depended on the particles size and dosage. The levels of reactive oxygen species (ROS) at 5, 10 mg/Kg bw of the three silica nanoparticles were higher than the fine silica particles. Blood levels of inflammation-related high-sensitivity C-reactive protein and cytokines such as interleukin-1beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha were increased after exposure to three silica nanoparticles at 10 mg/Kg bw. Moreover, the levels of IL-1β and IL-6 at 10 mg/Kg bw of silica nanoparticles (30 nm) were higher than the fine silica particles. Significant decrease in superoxide dismutase, glutathione peroxidase and significant increase in malondialdehyde were observed at 10 mg/Kg bw of the three silica nanoparticles. A significant decrease in nitric oxide (NO) production was induced which coincided with the reduction of nitric oxide synthase (NOS) activity and the excessive generation of ROS in rats. The levels of intercellular adhesion molecule-l and vascular cell adhesion molecule-l elevated significantly after exposure to three silica nanoparticles at 10 mg/Kg bw, which are considered as early steps of endothelial dysfunction. We conclude that cardiovascular toxicity of silica nanoparticles could be related to the particles size and dosage. Oxidative stress could be involved in inflammatory reaction and endothelial dysfunction, all of which could aggravate cardiovascular toxicology. In addition, endothelial NO/NOS system disorder caused by nanoparticles could be one of the mechanisms for endothelial dysfunction.     

Differential impact of peripheral endothelial dysfunction on subsequent cardiovascular events following percutaneous coronary intervention between chronic kidney disease (CKD) and non-CKD patients

Chronic kidney disease (CKD) status might modify the predictive effect of peripheral endothelial dysfunction on cardiovascular events after percutaneous coronary intervention (PCI). The aim of this study was to examine the differential effect of peripheral endothelial dysfunction on clinical outcome after PCI between CKD and non-CKD patients. We conducted a cohort study of 435 patients following PCI. CKD was defined as estimated glomerular filtration rate <60 mL/min/1.73 m². Peripheral endothelial dysfunction was examined using reactive hyperemia-peripheral arterial tonometry index (RHI), and we divided patients into low- and high-natural logarithmic RHI (Ln-RHI) group. The endpoint was a composite of cardiovascular death, nonfatal myocardial infarction, ischemic stroke, hospitalization due to unstable angina pectoris, and coronary revascularization. A total of 56 patients had a cardiovascular event. Patients who suffered a cardiovascular event had significantly lower Ln-RHI than other patients in the non-CKD group (0.46 ± 0.18 versus 0.60 ± 0.25; P = 0.002). Kaplan–Meier analysis demonstrated a significantly higher probability of cardiovascular events in low Ln-RHI patients in the non-CKD group (log-rank test: P = 0.003). Multivariate Cox proportional hazards analysis identified Ln-RHI as an independent and significant predictor of future cardiovascular events in the non-CKD group (HR: 0.096; 95 % CI 0.02–0.47; P = 0.004) but not in the CKD group. There was a differential effect of peripheral endothelial dysfunction on clinical outcome after PCI between CKD and non-CKD patients, and peripheral endothelial dysfunction significantly correlates with subsequent cardiovascular events after PCI in non-CKD patients.     

Spironolactone improves endothelial dysfunction in ankylosing spondylitis

Chronic inflammation in ankylosing spondylitis (AS) is associated with vascular endothelial dysfunction which leads to accelerated atherosclerosis. Accelerated atherosclerosis contributes to premature cardiovascular disease and increased cardiovascular mortality in AS. Spironolactone inhibits the production of proinflammatory cytokines and improves endothelial dysfunction in rheumatoid arthritis. This study aimed to determine the effect of spironolactone in antitumor necrosis factor (TNF)-naive AS patients. Twenty anti-TNF-naive AS patients (M/F?=?15/5) with high disease activity (Bath ankylosing spondylitis disease activity index, BASDAI >4) despite treatment with stable doses of conventional disease-modifying antirheumatic drugs were investigated. Inflammatory disease activity (BASDAI and Bath ankylosing spondylitis functional index (BASFI) scores, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels), serum nitrite concentration, and endothelium-dependent and -independent vasodilatation of the brachial artery were measured at baseline and after 12 weeks of therapy with oral spironolactone 2 mg/kg/day. Ten healthy subjects matched for age and sex acted as the control. Flow-mediated dilation (FMD) in AS patients at baseline was significantly impaired compared with healthy control group (p?<?0.001). After treatment, FMD improved from 11.3?±?1.70 to 24.69?±?2.34 % (p?<?0.001); nitrite concentration reduced from 7.9?±?0.28 to 4.79?±?0.19 μmol/L (p?<?0.001); ESR from 33.8?±?4.38 to 15.13?±?1.30 mm in the first hour, (p?<?0.001); and CRP level from 22.39?±?3.80 to 6.3?±?1.29 mg/dL, (p?<?0.001). BASDAI and BASFI also reduced significantly (p?<?0.001). The study suggests that in AS endothelial dysfunction is a part of the disease process. This is the first study to show that treatment with spironolactone improves both endothelial dysfunction and inflammatory disease activity in AS.     

<Emphasis Type="Italic">Kolaviron</Emphasis> was protective against sodium azide (NaN<Subscript>3</Subscript>) induced oxidative stress in the prefrontal cortex

Kolaviron is a phytochemical isolated from Garcina kola (G. kola); a common oral masticatory agent in Nigeria (West Africa). It is a bioflavonoid used - as an antiviral, anti-inflammatory and antioxidant - in relieving the symptoms of several diseases and infections. In this study we have evaluated the neuroprotective and regenerative effect of kolaviron in neurons of the prefrontal cortex (Pfc) before or after exposure to sodium azide (NaN₃) induced oxidative stress. Separate groups of animals were treated as follows; kolaviron (200 mg/Kg) for 21 days; kolaviron (200 mg/Kg for 21 days) followed by NaN₃ treatment (20 mg/Kg for 5 days); NaN₃ treatment (20 mg/Kg for 5 days) followed by kolaviron (200 mg/Kg for 21 days); 1 ml of corn-oil (21 days-vehicle); NaN₃ treatment (20 mg/Kg for 5 days). Exploratory activity associated with Pfc function was assessed in the open field test (OFT) following which the microscopic anatomy of the prefrontal cortex was examined in histology (Haematoxylin and Eosin) and antigen retrieval Immunohistochemistry to show astroglia activation (GFAP), neuronal metabolism (NSE), cytoskeleton (NF) and cell cycle dysregulation (p53). Subsequently, we quantified the level of Glucose-6-phosphate dehydrogenase (G6PDH) and lactate dehydrogenase (LDH) in the brain tissue homogenate as a measure of stress-related glucose metabolism. Kolaviron (Kv) and Kolaviron/NaN₃ treatment caused no prominent change in astroglia density and size while NaN₃ and NaN₃/Kv induced astroglia activation and scar formation (astrogliosis) in the Pfc when compared with the control. Similarly, Kolaviron and Kv/NaN₃ did not alter NSE expression (glucose metabolism) while NaN₃ and NaN₃/Kv treatment increased cortical NSE expression; thus indicating stress related metabolism. Further studies on enzymes of glucose metabolism (G6PDH and LDH) showed that NaN₃ increased LDH while kolaviron reduced LDH in the brain tissue homogenate (P?<?0.001). In addition kolaviron treatment before (P?<?0.001) or after (P?<?0.05) NaN₃ treatment also reduced LDH expression; thus supporting its role in suppression of oxidative stress. Interestingly, NF deposition increased in the Pfc after kolaviron treatment while Kv/NaN₃ showed no significant change in NF when compared with the control. In furtherance, NaN₃ and NaN₃/Kv caused a decrease in NF deposition (degeneration). Ultimately, the protective effect of KV administered prior to NaN₃ treatment was confirmed through p53 expression; which was similar to the control. However, NaN₃ and NaN₃/Kv caused an increase in p53 expression in the Pfc neurons (cell cycle dysregulation). We conclude that kolaviron is not neurotoxic when used at 200 mg/Kg BW. Furthermore, 200 mg/Kg of kolaviron administered prior to NaN₃ treatment (Kv/NaN₃) was neuroprotective when compared with Kolaviron administered after NaN₃ treatment (NaN₃/Kv). Some of the observed effects of kolaviron administered before NaN₃ treatment includes reduction of astroglia activation, absence of astroglia scars, antioxidation (reduced NSE and LDH), prevention of neurofilament loss and cell cycle regulation.     

The cardiovascular health score and the volume of carotid body in computed tomography angiography in patients with arterial hypertension

The cardiovascular health (CVH) score constitutes a reliable and measurable indicator of CVH proposed by the American Heart Association (AHA) calculated based on seven fundamental parameters, that is, smoking, body mass index, physical activity, healthy diet score, blood pressure, blood cholesterol, and fasting plasma glucose. The size and activity of carotid body (CB) play an important role in the pathogenesis of the cardiovascular system. The objective of this study was to define the relationship between the AHA CVH score and the volume of CB (V_rCB+lCB) estimated based on computed tomography angiography (CTA) in patients with arterial hypertension. Studies were conducted on a group of 57 patients with arterial hypertension (age: 70.74 ± 8.21 years). The CVH score was calculated, and CTA of carotid arteries was carried out for all patients. The CB analysis was performed based on delayed phase imaging obtained from CTA of carotid arteries. Based on the CVH score value, CVH was determined as optimal (CVH score between 10 and 14 points), average (5 and 9 points), or inadequate (0 and 4 points). CVH score in the studied group of patients was 6.53 ± 1.81, whereas V_rCB+lCB value was 38.58 ± 18.43 mm³. Patients with an inadequate CVH score (0–4 points) have statistically significantly higher V_rCB+lCB, and they are fraught with V_rCB+lCB ≥ median much more often than patients with an optimal CVH score (10–14 points). The receiver operating characteristic curve indicated a CVH score value of 6 as an optimal cutoff point to predict V_rCB+lCB ≥ median. The CVH score ≤6 criterion indicates V_rCB+lCB ≥ median with sensitivity of 58.6% and specificity of 71.4%. In the regression analysis, it was indicated that lower partial scores for physical activity, healthy diet score, and blood pressure in the AHA CVH evaluation constitute independent risk factors for higher V_rCB+lCB. In the studied group of patients with arterial hypertension, an inversely proportional dependence between the CVH score and the size of CB is observed in CTA of carotid arteries.     

Attenuation of Cardiovascular Remodeling in DOCA-Salt Rats by the Vasopeptidase Inhibitor,Omapatrilat

Omapatrilat, a vasopeptidase inhibitor, inhibits both neutral endopeptidase and angiotensin-converting enzyme with similar potency. The aim of this study was to investigate whether omapatrilat prevents or reverses cardiovascular remodeling and hypertension in deoxycorticosterone acetate (DOCA)-salt rats. Male Wistar rats (313 ± 2 g, n=114) were uninephrectomized (UNX) with or without further treatment with DOCA and 1% NaCl in the drinking water. Compared with UNX control rats, DOCA-salt rats developed hypertension, cardiovascular hypertrophy, perivascular and interstitial cardiac fibrosis and inflammation, endothelial dysfunction, and the prolongation of ventricular action potential duration within four weeks. The administration of omapatrilat (40 mg/kg/day po) for two weeks commencing two weeks after surgery attenuated the development of cardiovascular hypertrophy, inflammation, fibrosis, and ventricular action potential prolongation. In contrast, omapatrilat treatment did not lower systolic blood pressure nor improve endothelial dysfunction. This study concludes that the renin-angiotensin-aldosterone, natriuretic peptide, and bradykinin systems are directly involved in the pathogenesis of cardiovascular remodeling in the DOCA-salt model of hypertension in rats, which may be independent of their effects on blood pressure.     

Memory deficits associated with khat (<Emphasis Type="Italic">Catha edulis</Emphasis>) use in rodents

Khat products and chewing practices are common in East Africa, Middle East for centuries with concomitant socio-economic and public health repercussions. We assessed memory deficits associated with khat use in rodents. Young male CBA mice, 5–7 weeks old (n?=?20), weighing 25–35 g were used. Mice were treated with either 40, 120 or 360 mg/kg body weight (bw) methanolic khat extract, or 0.5 ml saline for 10 days. Spatial acquisition, reversal and reference memory were assessed using modified Morris Water maze (MMWM). Mice treated with 40 mg/kg khat extract had longer (t₄?=?4.12 p?=?0.015) and t₄?=?2.28 p?=?0.065) escape latency on first and second day during reversal relative to the baseline. Under 120 mg/kg khat dose, the escape latency was shorter (t₄?=??2.49 p?=?0.05) vs (t₃?=??2.5 p?=?0.05) on third and fourth day. Further, treatment with 360 mg/kg khat extract resulted in significantly longer time (49.13, 33.5, 40.2 and 35.75) vs. (23.5 s), compared to baseline. Mice treated with khat or control preferred the target quadrant post acquisition while differential pattern was seen during reversal phase. Mice treated with 40 or 120 mg/kg khat showed significant preference for target quadrant. Substantial time (19.9) was spent in the old target compared to the new (16.9 s) by animals treated with highest dose however, the difference was not significant. There is a biological plausibility that chronic khat use may induce memory deficits and impair cognitive flexibility. The differential patterns of memory deficits may reflect the differences in dose effect as well as time dependent impairment.     

Additive effect of homocysteine- and cholesterol-lowering therapy on endothelium-dependent vasodilation in patients with cardiovascular disease

Aim : Endothelial dysfunction is a marker for development and progression of atherosclerosis. Statin therapy improves endothelial function in cardiovascular patients by reducing LDL‐cholesterol and by pleiotropic effects. B‐group vitamin supplementation restores endothelial function mainly by reducing homocysteine‐induced oxidative stress. Thus, we evaluated the effect of rosuvastatin, B‐group vitamins and their combination on endothelial function in high‐risk cardiovascular patients. Methods : Thirty‐six patients with cardiovascular disease were randomly, double‐blinded assigned to either rosuvastatin 10 mg (group R, n = 18) or vitamin supplementation consisting of folic acid 1 mg, vitamin B12 0.4 mg, and B6 10 mg (group V, n = 18) for 6 weeks. After 6 weeks all patients received rosuvastatin and vitamin supplementation in combination for additional 6 weeks. Endothelial function was assessed by flow‐mediated vasodilation (FMD) at baseline and after 6‐ and 12‐week treatment. Results : At baseline, FMD, plasma lipids, vitamins, and homocysteine were comparable between both groups. After 6 weeks, FMD improved in both groups (from 4.4 ± 1.6 to 6.9 ± 1.4% group R, P= 0.0004 and from 4.9 ± 1.8 to 6.4 ± 1.8% group V, P= 0.0002). This improvement in FMD was mainly associated with a decrease of plasma lipids in group R and a decrease of homocysteine in group V. After 12 weeks, the combined therapy with rosuvastatin and vitamins further improved FMD to the normal range in 26/33 patients compared to 5/36 at baseline (P < 0.0001). Conclusions : In conclusion, both treatments, rosuvastatin and B‐group vitamin supplementation, improved endothelial function in high‐risk cardiovascular patients. The combination of both therapies had an additive effect on endothelial function suggesting different mechanisms of action.     

Contribution of electromechanical coupling between KV and CaV1.2 channels to coronary dysfunction in obesity

Previous investigations indicate that diminished functional expression of voltage-dependent K⁺ (K_V) channels impairs control of coronary blood flow in obesity/metabolic syndrome. The goal of this investigation was to test the hypothesis that K_V channels are electromechanically coupled to Ca_V1.2 channels and that coronary microvascular dysfunction in obesity is related to subsequent increases in Ca_V1.2 channel activity. Initial studies revealed that inhibition of K_V channels with 4-aminopyridine (4AP, 0.3 mM) increased intracellular [Ca²⁺], contracted isolated coronary arterioles and decreased coronary reactive hyperemia. These effects were reversed by blockade of Ca_V1.2 channels. Further studies in chronically instrumented Ossabaw swine showed that inhibition of Ca_V1.2 channels with nifedipine (10 μg/kg, iv) had no effect on coronary blood flow at rest or during exercise in lean swine. However, inhibition of Ca_V1.2 channels significantly increased coronary blood flow, conductance, and the balance between coronary flow and metabolism in obese swine (P < 0.05). These changes were associated with a ~50 % increase in inward Ca_V1.2 current and elevations in expression of the pore-forming subunit (α₁c) of Ca_V1.2 channels in coronary smooth muscle cells from obese swine. Taken together, these findings indicate that electromechanical coupling between K_V and Ca_V1.2 channels is involved in the regulation of coronary vasomotor tone and that increases in Ca_V1.2 channel activity contribute to coronary microvascular dysfunction in the setting of obesity.     

Dietary antioxidant supplementation reduces lipid peroxidation but impairs vascular function in small mesenteric arteries of the streptozotocin-diabetic rat

Summary Impaired endothelium-dependent relaxation could underlie many of the vascular complications associated with insulin-dependent diabetes mellitus, and may be mediated by increased oxidative stress. The effect of antioxidants on vascular endothelial function and oxidative stress of streptozotocin-diabetic rats was assessed by dietary supplementation with vitamins E and C. Diabetic (i. v. streptozotocin, 45 mg/kg) male Sprague-Dawley rats were fed one of six supplemented diets containing 75.9, 250, or 500 mg vitamin E/kg chow, 250 mg vitamin C/kg H₂0, 250 mg vitamin E/kg chow plus 250 mg vitamin C/kg H₂O, or chow deficient in vitamin E, and then compared to standard-fed control rats. After 4 weeks, small mesenteric arteries were dissected and mounted on a small vessel myograph, concentration response curves were then constructed to noradrenaline, acetylcholine and sodium nitroprusside. Acetylcholine-mediated relaxation was impaired in arteries from diabetic rats (pEC₅₀ 6.701 ± SEM 0.120, n = 8) compared to controls (7.386 ± 0.078, n = 6; p < 0.05). The 500 mg/kg vitamin E diet further impaired maximum relaxation to acetylcholine (58.2 ± 10.5 vitamin E, n = 7 vs 84.4 ± 5.3 % standard, p < 0.05), and the combined vitamin E plus C diet impaired maximum relaxation to sodium nitroprusside (48.5 ± 4.1 in vitamin E + C, n = 8 vs 75.6 ± 3.9 % standard; p < 0.01). However, plasma 8-epi-prostaglandin (PG)F₂α (measured as an estimate of oxidative stress) was dose-dependently decreased in rats on vitamin E supplemented diets. Dietary antioxidant supplementation did not reverse impaired endothelial function in this model of uncontrolled diabetes despite a concomitant decrease in oxidative stress. [Diabetologia (1998) 41: 148–156] Received: 8 July 1997 and in revised form: 29 September 1997     

H<Subscript>3</Subscript> histamine receptor antagonist pitolisant reverses some subchronic disturbances induced by olanzapine in mice

The use of atypical antipsychotic drugs like olanzapine is associated with side effects such as sedation and depression-like symptoms, especially during the initial period of the use. It is believed that the occurrence of these undesirable effectsis mainly the result of the histamine H₁receptors blockade by olanzapine. In addition, use of olanzapine increases the level of triglycerides in the blood, which correlates with growing obesity. The aim of this study was to investigate the influence of pitolisant – H₃ histamine antagonist - on subchronic olanzapine-induced depresion-like symptoms, sedation and hypertriglicerydemia. Forced swim test was conducted to determinate depressive-like effect of olanzapine and antidepressive-like activity during the co-administered pitolisant. The test was performed after the first and fifteenth day of the treatment of the mice. The spontaneous activity of the mice was measured on the fourteenth day of the treatment with a special, innovative RFID-system (Radio-frequency identification system) – TraffiCage (TSE-Systems, Germany). Triglyceride levels were determined on the sixteenth day of the experiment after 15 cycles of drug administration. Daily olanzapine treatment (4 mg/kg b.w., i.p., d.p.d) for 15 days significantly induces sedation (p < 0.05) and prolongs immobility time in forced swim tests (FST) in mice (p < 0.05); and also elevates the level of triglycerides (p < 0.05). Administration of pitolisant (10 mg/kg b.w., i.p.) subsequentto olanzapine normalizes these adverse effects. This study presents a promising alternative for counteracting some behavioral changes and metabolic disturbances which occur in the early period of treatment with antipsychotic drugs.