Leukocyte-endothelium interaction during the early stages of hypercholesterolemia in the rabbit: role of P-selectin, ICAM-1, and VCAM-1

A Systematic Review of Cardio-Metabolic Properties of Lonicera caerulea L

In the light of growing concerns faced by Western societies due to aging, natality decline, and epidemic of cardio-metabolic diseases, both preventable and treatable, new and effective strategical interventions are urgently needed in order to decrease their socio-economical encumbrance. The recent focus of research has been redirected towards investigating the potential of haskap (Lonicera caerulea L.) as a novel functional food or superfruit. Therefore, our present review aims to highlight the latest scientific proofs regarding the potential of Lonicera caerulea L. (LC), a perennial fruit-bearing plant rich in polyphenols, in reversing cardio-metabolic dysfunctions. In this regard, a systematic search on two databases (PubMed and Google Scholar) from 1 January 2016 to 1 December 2023 was performed, the keyword combination being Lonicera caerulea L. AND the searched pharmacological action, with the inclusion criteria consisting of in extenso original articles, written in English. The health-enhancing characteristics of haskap berries have been examined through in vitro and in vivo studies from the 35 included original papers. Positive effects regarding cardiovascular diseases and metabolic syndrome have been assigned to the antioxidant activity, hypolipidemic and hypoglycemic effects, as well as to the hepatoprotective and vasoprotective potential. Latest advances regarding LCF mechanisms of action are detailed within this review as well. All these cutting-edge data suggest that this vegetal product would be a good candidate for further clinical studies.

Coronary microvascular dysfunction

Coronary microvascular dysfunction (CMD) is a key mechanism underlying ischemic heart disease (IHD), yet its diagnosis and treatment remain challenging. This article presents a comprehensive overview of CMD research, covering its pathogenesis, diagnostic criteria, assessment techniques, risk factors, and therapeutic strategies. Additionally, it highlights the prospects for future CMD research. The article aims at advocating early and effective intervention for CMD and improving the prognosis of IHD.

Are higher levels of lipid profile parameters associated with increased chances of uncontrolled asthma among adults?

BACKGROUND

Studies on the relationship between asthma and various parameters of fasting lipid profile have reported conflicting results. In this study, we intend to explore this association between asthma and its level of control with fasting serum lipid profile further.

METHODS

In our observational prospective cohort study, we studied 107 known asthmatic patients presenting in large tertiary care centre of North India. Fasting serum samples for lipid profile reports of all patients were collected. Patients were divided into controlled and uncontrolled asthma groups on the basis of clinical symptoms and spirometric findings. We evaluated the statistical difference and significance for various lipid profile parameters in between two groups using an independent t-test.

RESULTS

On comparing the fasting lipid profile of 38 patients with uncontrolled asthma and 69 patients with controlled asthma, we found that serum levels of low-density lipoprotein (LDL) and ratio of total cholesterol to high-density lipoprotein (TC: HDL) were significantly higher among patients with uncontrolled asthma. On statistical analysis, their P values were 0.03 and 0.047, respectively.

CONCLUSION

Serum levels of LDL and ratio of TC: HDL were higher in patients with uncontrolled asthma.

The effect of circulating iron on barrier integrity of primary human endothelial cells

Iron is hypothesized to be one of the contributors to cardiovascular disease and its levels in the circulation may correlate with cardiovascular risk. The aim of this study is to investigate the mechanisms that underlie the effects of iron on the barrier function of primary human endothelium. We used Human Umbilical Vein Endothelial Cells (HUVEC) to investigate the effects of Fe3+ using electric cell-substrate impedance sensing, microscopy, western blot and immunofluorescence microscopy. Exposure to Fe3+ caused EC elongation and upregulation of stress-induced proteins. Analysis of barrier function showed a dose-dependent drop in endothelial integrity, which was accompanied by Reactive Oxygen Species (ROS) production and could partly be prevented by ROS scavengers. Inhibition of contractility by the ROCK inhibitor Y27632, showed even more effective rescue of barrier integrity. Using western blot, we detected an increase in expression of the small GTPase RhoB, an inducer of EC contraction, and a small decrease in VE-cadherin, suggestive for an iron-induced stress response. Co-stimulation by TNFα and iron, used to investigate the role of low-grade inflammation, revealed an additive, negative effect on barrier integrity, concomitant with an upregulation of pro-inflammatory markers ICAM-1 and RhoB. Iron induces a response in HUVEC that leads to endothelial activation and a pro-inflammatory state measured by loss of barrier integrity which can be reversed by ROS scavengers, combined with inhibition of contractility. These data suggest that ROS-mediated damage of the vascular endothelium could contribute to the increased cardiovascular risk which is associated with elevated levels of circulating iron.

Establishment and application of a high-throughput screening model for cell adhesion inhibitors

The cell adhesion between leukocytes and endothelial cells plays an important balanced role in the pathophysiological function, while excessive adhesion caused by etiological agents is associated with the occurrence and development of many acute and chronic diseases. Cell adhesion inhibitors have been shown to have a potential therapeutic effect on these diseases, therefore, efficient and specific inhibitors against cell adhesion are highly desirable. Here, using lipopolysaccharide-induced human umbilical vein endothelial cells (HUVECs) and calcein-AM-labeled human monocytic cell THP-1, we established a high-throughput screening model for cell adhesion inhibitors with excellent model evaluation parameters. Using the drug repurposing strategy, we screened out lifitegrast, a potent cell adhesion inhibitor, which inhibited cell adhesion between HUVEC and THP-1 cells by directly interrupting the adhesion interaction between HUVEC and THP-1 cells and showed a strong therapeutic effect on the mouse acute liver injury induced by poly (I:C)/D-GalN. Therefore, the screening model is suitable for screening and validating cell adhesion inhibitors, which will promote the research and development of inhibitors for the treatment of diseases caused by excessive cell adhesion.

Pinitol Protects Against Ox-Low-Density Lipoprotein-Induced Endothelial Inflammation and Monocytes Attachment

ABSTRACT

Atherosclerosis is a cardiovascular disease that affects a majority of people around the world at old age. Atherosclerosis is slow to develop and challenging to treat. Endothelial dysfunction caused by oxidative stress, inflammation, and other pathological factors drives the process of atherogenesis. LOX-1 is one of the main scavenging receptors for oxidized low-density lipoprotein (ox-LDL) and contributes to atherogenesis by inducing overproduction of reactive oxygen species, increased expression of proinflammatory cytokines, and secretion of cellular adhesion molecules. In addition, activation of LOX-1 inhibits the expression of KLF2, a key protective factor against atherosclerosis. In this study, we investigated the effects of pinitol, and naturally occurring cyclic polyol, on endothelial dysfunction induced by ox-LDL. Our findings show that pinitol revealed a good safety profile, as evidenced by reducing lactate dehydrogenase release in human aortic endothelial cells. In our experiments, pinitol reduced the production of reactive oxygen species and expression of IL-6 and monocyte chemoattractant protein-1 induced by ox-LDL. Pinitol also significantly reduced the attachment of THP-1 monocytes to endothelial cells via downregulation of vascular cellular adhesion molecule-1 and E-selectin. Importantly, we found that pinitol reduced the expression of LOX-1 induced by ox-LDL and rescued the expression of KLF2, which is dependent on ERK5 expression. Together, our findings provide notable evidence that pinitol may have potential implication in the prevention and treatment of atherosclerosis.

Gamma-glutamyl carboxylated Gas6 facilitates the prophylactic effect of vitamin K in inhibiting hyperlipidemia-associated inflammatory pathophysiology via arresting MCP-1/ICAM-1 mediated monocyte-hepatocyte adhesion

Role of growth arrest-specific 6 (Gas6), member of vitamin K (VK)-dependent protein family in hyperlipidemia-associated inflammation remains unresolved. To address this, blood samples were collected from hyperlipidemic subjects and age-matched healthy controls and observed that gamma-glutamyl carboxylated Gas6 (Gla-Gas6) but not total Gas6 were significantly lower while pro-inflammatory markers, MCP-1 and ICAM-1 were remarkably higher in hyperlipidemic subjects compared to control. Correlation analyses demonstrated that Gla-Gas6 levels were inversely correlated with MCP-1 and ICAM-1 but positively with plasma VK in hyperlipidemic subjects but not in control. This suggests that boosting VK level might ameliorate the hyperlipidemia-associated inflammatory pathophysiology via augmenting Gla-Gas6. Further studies with high fat diet (HFD)-fed mice demonstrated that VK supplementation (1, 3, and 5 µg/kg BW, 8 weeks) dose-dependently reduced both hepatic and plasma levels of MCP-1 and ICAM-1 while elevating that of Gla-Gas6 but not total Gas6 in HFD-fed mice. Cell culture studies with gamma-glutamyl carboxylase (enzyme causes VK-dependent carboxylation of Gas6) knockdown hepatocytes and monocytes dissected the direct role of Gla-Gas6 in inhibiting high palmitic acid (0.75 mM)-induced inflammation via arresting MCP-1/ICAM-1 mediated hepatocyte-monocyte adhesion. The present study demonstrated an important role of Gla-Gas6 in facilitating the prophylactic effect of VK against hyperlipidemia associated inflammation.

NOS1-mediated macrophage and endothelial cell interaction in the progression of atherosclerosis

Atherosclerosis is a chronic inflammatory disease arising due to an imbalance in lipid metabolism and maladaptive immune response driven by the accumulation of cholesterol-laden macrophages in the artery wall. Interactions between monocytes/macrophages and endothelial cells play an essential role in the pathogenesis of atherosclerosis. In our current study, nitric oxide synthase 1 (NOS1)-derived nitric oxide (NO) has been identified as a regulator of macrophage and endothelial cell interaction. Oxidized LDL (OxLDL) activates NOS1, which results in the expression of CD40 ligand in macrophages. OxLDL-stimulated macrophages produce some soluble factors which increase the CD40 receptor expression in endothelial cells. This increases the interaction between the macrophages and endothelial cells, which leads to an increase in the inflammatory response. Inhibition of NOS1-derived NO might serve as an effective strategy to reduce foam cell formation and limit the extent of atherosclerotic plaque expansion.

Effect of Lavandula dentata extract on Ovalbumin-induced Asthma in Male Guinea Pigs

Asthma is an inflammatory disease of the lungs, and it causes oxidative stress. Lavandula dentata is an aromatic herb with anti-oxidative and anti-inflammatory activities. This study examined the activity of L. dentata extract on a guinea pig model of asthma. Adult males were divided into five groups: First group was control, second was asthma model induced by OVA, third was treated with L. dentata extract orally (300 mg/kg) for 21 days; the fourth was an asthma model with L. dentata extract (300 mg/kg) and fifth was treated with Tween 80 for 21 days. OVA treatment increased IgE, triglycerides, total cholesterol, glucose levels in serum, WBC count in blood and MDA in lungs. Also, OVA reduced SOD activity, GSH content in lungs, and GGT activity in serum (p<0.05). L. dentata extract treatment in asthma model reduced elevated IgE, triglycerides, total cholesterol, glucose levels in serum, and MDA in lungs (p<0.05), while it increased GSH content in lungs (p<0.05). These results suggest the possibility that L . dentata extract can exert suppressive effects on asthma, and may provide evidence that it is a useful agent for the treatment of allergic airway disease, it also limits oxidative stress induced by OVA. L. dentata extract appears to have hypolipidemic and hypoglycemic activities.

Assessment of ICAM-1 N-glycoforms in mouse and human models of endothelial dysfunction

Endothelial dysfunction is a critical event in vascular inflammation characterized, in part, by elevated surface expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1). ICAM-1 is heavily N-glycosylated, and like other surface proteins, it is largely presumed that fully processed, complex N-glycoforms are dominant. However, our recent studies suggest that hypoglycosylated or high mannose (HM)-ICAM-1 N-glycoforms are also expressed on the cell surface during endothelial dysfunction, and have higher affinity for monocyte adhesion and regulate outside-in endothelial signaling by different mechanisms. Whether different ICAM-1 N-glycoforms are expressed in vivo during disease is unknown. In this study, using the proximity ligation assay, we assessed the relative formation of high mannose, hybrid and complex α-2,6-sialyated N-glycoforms of ICAM-1 in human and mouse models of atherosclerosis, as well as in arteriovenous fistulas (AVF) of patients on hemodialysis. Our data demonstrates that ICAM-1 harboring HM or hybrid epitopes as well as ICAM-1 bearing α-2,6-sialylated epitopes are present in human and mouse atherosclerotic lesions. Further, HM-ICAM-1 positively associated with increased macrophage burden in lesions as assessed by CD68 staining, whereas α-2,6-sialylated ICAM-1 did not. Finally, both HM and α-2,6-sialylated ICAM-1 N-glycoforms were present in hemodialysis patients who had AVF maturation failure compared to successful AVF maturation. Collectively, these data provide evidence that HM- ICAM-1 N-glycoforms are present in vivo, and at levels similar to complex α-2,6-sialylated ICAM-1 underscoring the need to better understand their roles in modulating vascular inflammation.

Lipid profiles in adolescents with and without asthma: Korea National Health and nutrition examination survey data

Background

Metabolic syndrome and dyslipidemia contribute to the development of a pro-inflammatory state in asthma. However, studies investigating the association between asthma and dyslipidemia have reported conflicting results. This study aimed to uncover the relationship between asthma and lipid profiles in adolescents using a national health and nutrition survey.

Methods

This cross-sectional study analyzed the 2010–2012 Korea National Health and Nutrition Examination Survey data and included 2841 subjects aged 11–18 years with fasting blood sample data. Serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) levels were analyzed. We compared asthma prevalence between high-risk and low-risk lipid groups.

Results

There were 123 adolescents with asthma and 2718 without asthma (controls). The TC/HDL-C ratio, LDL-C/HDL-C ratio, and non-HDL-C levels were significantly higher in the asthma group than in the non-asthma group (P < 0.05). The high-risk groups displayed significantly higher asthma prevalence with higher TC, TG, LDL-C, and non-HDL-C levels and TG/HDL-C ratio than the low-risk groups (P < 0.05). After adjusting for potential confounding factors, the high-risk groups were associated with asthma according to their higher TC levels (adjusted odds ratio, 1.69; 95% confidence interval, 1.012–2.822) and TG/HDL-C ratios (adjusted odds ratio, 1.665; 95% confidence interval, 1.006–2.756).

Conclusions

Asthma prevalence was greater in adolescents with a high TC level and TG/HDL-C ratio. In addition to the standard lipid profile, elevated TG/HDL-C ratio can be used as a useful additional lipid measure to evaluate interactions between dyslipidemia and asthma.

Peripheral Inflammation, Apolipoprotein E4, and Amyloid-β Interact to Induce Cognitive and Cerebrovascular Dysfunction

Cerebrovascular dysfunction is rapidly reemerging as a major process of Alzheimer’s disease (AD). It is, therefore, crucial to delineate the roles of AD risk factors in cerebrovascular dysfunction. While apolipoprotein E4 (APOE4), Amyloid-β (Aβ), and peripheral inflammation independently induce cerebrovascular damage, their collective effects remain to be elucidated. The goal of this study was to determine the interactive effect of APOE4, Aβ, and chronic repeated peripheral inflammation on cerebrovascular and cognitive dysfunction in vivo. EFAD mice are a well-characterized mouse model that express human APOE3 (E3FAD) or APOE4 (E4FAD) and overproduce human Aβ42 via expression of 5 Familial Alzheimer’s disease (5xFAD) mutations. Here, we utilized EFAD carriers [5xFAD^+/−/APOE^+/+ (EFAD+)] and noncarriers [5xFAD^−/−/APOE^+/+ (EFAD−)] to compare the effects of peripheral inflammation in the presence or absence of human Aβ overproduction. Low-level, chronic repeated peripheral inflammation was induced in EFAD mice via systemic administration of lipopolysaccharide (LPS; 0.5 mg/kg/wk i.p.) from 4 to 6 months of age. In E4FAD+ mice, peripheral inflammation caused cognitive deficits and lowered post-synaptic protein levels. Importantly, cerebrovascular deficits were observed in LPS-challenged E4FAD+ mice, including cerebrovascular leakiness, lower vessel coverage, and cerebral amyloid angiopathy-like Aβ deposition. Thus, APOE4, Aβ, and peripheral inflammation interact to induce cerebrovascular damage and cognitive deficits.

Loss of Reelin protects against atherosclerosis by reducing leukocyte-endothelial cell adhesion and lesion macrophage accumulation

The multimodular glycoprotein Reelin controls neuronal migration and synaptic transmission by binding to apolipoprotein E receptor 2 (Apoer2) and very low density lipoprotein receptor (Vldlr) on neurons. In the periphery, Reelin is produced by the liver, circulates in blood, and promotes thrombosis and hemostasis. To investigate if Reelin influences atherogenesis, we studied atherosclerosis-prone low-density lipoprotein receptor-deficient (Ldlr(-/-)) mice in which we inducibly deleted Reelin either ubiquitously or only in the liver, thus preventing the production of circulating Reelin. In both types of Reelin-deficient mice, atherosclerosis progression was markedly attenuated, and macrophage content and endothelial cell staining for vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were reduced at the sites of atherosclerotic lesions. Intravital microscopy revealed decreased leukocyte-endothelial adhesion in the Reelin-deficient mice. In cultured human endothelial cells, Reelin enhanced monocyte adhesion and increased ICAM1, VCAM1, and E-selectin expression by suppressing endothelial nitric oxide synthase (eNOS) activity and increasing nuclear factor κB (NF-κB) activity in an Apoer2-dependent manner. These findings suggest that circulating Reelin promotes atherosclerosis by increasing vascular inflammation, and that reducing or inhibiting circulating Reelin may present a novel approach for the prevention of cardiovascular disease.

Intercellular adhesion molecule-1 expression in the hippocampal CA1 region of hyperlipidemic rats with chronic cerebral ischemia

Chronic cerebral ischemia is a pathological process in many cerebrovascular diseases and it is induced by long-term hyperlipidemia, hypertension and diabetes mellitus. After being fed a high-fat diet for 4 weeks, rats were subjected to permanent occlusion of bilateral common carotid arteries to establish rat models of chronic cerebral ischemia with hyperlipidemia. Intercellular adhesion molecule-1 expression in rat hippocampal CA1 region was determined to better understand the mechanism underlying the effects of hyperlipidemia on chronic cerebral ischemia. Water maze test results showed that the cognitive function of rats with hyperlipidemia or chronic cerebral ischemia, particularly in rats with hyperlipidemia combined with chronic cerebral ischemia, gradually decreased between 1 and 4 months after occlusion of the bilateral common carotid arteries. This correlated with pathological changes in the hippocampal CA1 region as detected by hematoxylin-eosin staining. Immunohistochemical staining showed that intercellular adhesion molecule-1 expression in the hippocampal CA1 region was noticeably increased in rats with hyperlipidemia or chronic cerebral ischemia, in particular in rats with hyperlipidemia combined with chronic cerebral ischemia. These findings suggest that hyperlipidemia aggravates chronic cerebral ischemia-induced neurological damage and cognitive impairment in the rat hippocampal CA1 region, which may be mediated, at least in part, by up-regulated expression of intercellular adhesion molecule-1.

Is serum cholesterol a risk factor for asthma?

BACKGROUND

Proinflammatory role of serum cholesterol in asthma has been recently explored with contradicting results. Clarity on the link between serum cholesterol and asthma may lead to new evolutions in planning management strategies. The objective of our study was to examine the relationship between the serum cholesterol, asthma and its characteristics.

MATERIALS AND METHODS

A total of 40 asthmatics and 40 normal subjects were examined cross-sectionally and their serum fasting cholesterol and serum high sensitivity C reactive protein (hsCRP) levels were measured along with other baseline investigations. All subjects were non-smokers.

RESULTS

Serum total cholesterol (mean ± SD) among asthmatics was 176.45 ± 30.77 mgs/dL as compared to 163.33 ± 26.38 mgs/dL among normal subjects (P < 0.05). This higher serum cholesterol level was found to be associated with asthma independent of age, gender, body mass index (BMI), socio-economic status and serum hsCRP levels. However, the association was only modest (adjusted odds ratio 1.033; 95% confidence interval [CI] 1.008-1.059). There was no association between the serum cholesterol and asthma characteristics such as duration of illness, intake of inhaled steroids and frequency of emergency department visits. Other risk factors identified were poor ventilation (adjusted odds ratio 9.27; 95%CI 1.83-46.99) and overcrowding (adjusted odds ratio 41.9; 95% CI 3.15-557.46) at home.

CONCLUSION

Our study found a modest but significant association between higher levels of serum cholesterol and asthma, which is independent of age, gender, BMI, socio-economic status and serum hsCRP. Future research is required in a larger population to substantiate above association and its clinical implications. Poor ventilation and overcrowding at home are risk factors for asthma possibly facilitating increased exposure to indoor allergens.

The anti-inflammatory effect of kaempferol on early atherosclerosis in high cholesterol fed rabbits

BACKGROUND

Atherosclerosis has been widely accepted as an inflammatory disease of vascular, adhesion molecules play an important role in the early progression of it. The aim of the present study was to evaluate the effect of kaempferol on the inflammatory molecules such as E-selectin (E-sel), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesionmolecule-1 (VCAM-1) and monocyte chemotactic protein-1 (MCP-1) in high cholesterol induced atherosclerosis rabbit models.

METHODS

Thirty male New Zealand white (NZW) rabbits were randomly divided into five groups, control group, model group, fenofibrate (12 mg/kg) group and kaempferol groups (150 mg/kg and 30 mg/kg). The rabbits were fed with a normal diet or a high cholesterol diet for 10 weeks. Levels of blood lipids, serum tumour-necrosis factor-alpha (TNF-α) and serum interleukin-1beta (IL-1β) were detected at the end of the sixth and tenth week. Malonaldehyde (MDA) level and superoxide dismutase (SOD) activity in serum were also determined. Lesion areas of the aorta were measured with morphometry analysis after ten weeks. Gene expression of E-sel, ICAM-1, VCAM-1 and MCP-1 in aortas was determined by RT-PCR (reverse transcription-polymerase chain reaction). Immunohistochemical staining was employed to measure protein expression of E-sel, ICAM-1, VCAM-1 and MCP-1.

RESULTS

Model rabbits fed with ten weeks of high-cholesterol diet developed significant progression of atherosclerosis. Compared with the control, levels of blood lipids, TNF-α, IL-1β and MDA increased markedly in serum of model rabbits, while SOD levels decreased. Gene and protein expressions of E-sel, ICAM-1, VCAM-1 and MCP-1 in atherosclerotic aortas increased remarkably in model group. However, comparing to the model rabbits, levels of TNF-α, IL-1β and MDA decreased significantly and serum SOD activity increased, gene and protein expressions of E-sel, ICAM-1, VCAM-1 and MCP-1 in aortas decreased significantly with the treatment of kaempferol.

CONCLUSION

Kaempferol shows anti-atherosclerotic effect by modulating the gene and protein expression of inflammatory molecules.

Effect of lycopene from Chlorella marina on high cholesterol-induced oxidative damage and inflammation in rats

Even though the role of all-trans lycopene from tomato in controlling atherosclerosis was reported, but no report is available on the cis-isomer of lycopene obtained from an easily available source green algae Chlorella marina. So in this study, Sprague Dawley rats fed with high-cholesterol diet were given standard drug lovastatin; algal lycopene (AL) (cis/all-trans 40:60) and tomato all-trans lycopene (TL) and the following parameters were studied. Total cholesterol, low-density lipoprotein, triglycerides were decreased significantly and the high-density lipoprotein levels were increased on treatment with AL. The activities of antioxidant enzymes catalase, superoxide dismutase, glutathione peroxidase, and glutathione reductase were found to be increased, whereas thiobarbituric acid reactive substances levels were decreased in AL when compared to the drug and TL-treated rats. The activities of inflammatory marker enzymes like cyclooxygenase, 15-lipoxygenase in monocytes and myeloperoxidase, C-reactive protein and ceruloplasmin levels in serum were found to be decreased on treatment with AL. Histopathological studies revealed that lycopene from this alga could reduce fatty liver and aortic plaque when compared to the drug and TL. Algal lycopene showed very significant antioxidant and anti-inflammatory effect in high-cholesterol fed rats. Therefore, AL from C. marina would be recommended for the treatment of hyperlipidemia.

Pleiotropic effects of simvastatin in physically trained ovariectomized rats

This study tested the hypothesis that simvastatin treatment can improve cardiovascular and autonomic functions and membrane lipoperoxidation, with an increased effect when applied to physically trained ovariectomized rats. Ovariectomized rats were divided into sedentary, sedentary+simvastatin and trained+simvastatin groups (n = 8 each). Exercise training was performed on a treadmill for 8 weeks and simvastatin (5 mg/kg) was administered in the last 2 weeks. Blood pressure (BP) was recorded in conscious animals. Baroreflex sensitivity was evaluated by the tachycardic and bradycardic responses to BP changes. Cardiac vagal and sympathetic effects were determined using methylatropine and propranolol. Oxidative stress was evaluated based on heart and liver lipoperoxidation using the chemiluminescence method. The simvastatin-treated groups presented reduced body weight and mean BP (trained+simvastatin = 99 ± 2 and sedentary+simvastatin = 107 ± 2 mmHg) compared to the sedentary group (122 ± 1 mmHg). Furthermore, the trained group showed lower BP and heart rate compared to the other groups. Tachycardic and bradycardic responses were enhanced in both simvastatin-treated groups. The vagal effect was increased in the trained+simvastatin group and the sympathetic effect was decreased in the sedentary+simvastatin group. Hepatic lipoperoxidation was reduced in sedentary+simvastatin (≈21%) and trained+simvastatin groups (≈57%) compared to the sedentary group. Correlation analysis involving all animals demonstrated that cardiac lipoperoxidation was negatively related to the vagal effect (r = -0.7) and positively correlated to the sympathetic effect (r = 0.7). In conclusion, improvement in cardiovascular and autonomic functions associated with a reduction of lipoperoxidation with simvastatin treatment was increased in trained ovariectomized rats.

Roles of apolipoprotein E (ApoE) and inducible nitric oxide synthase (iNOS) in inflammation and apoptosis in preeclampsia pathogenesis and progression

Objectives

To investigate potential roles of inducible nitric oxide synthase (iNOS) and apolipoprotein (apoE) in inflammation and apoptosis promoting pathological changes in preeclampsia in pregnant mice with apoE and/or iNOS knock out.

Methods

B6.129 mice were crossed to produce WT, apoE^−/−, apoE^+/−, iNOS^−/−, iNOS^+/− and apoE^−/−iNOS^−/− groups. Variants were confirmed by PCR. Serum lipid parameters (triglycerides, TG; total cholesterol, TC; high density lipoprotein, HDL; and low density lipoprotein, LDL), NO levels and placental electronic microscopic ultrastructures were evaluated, and blood pressure (BP), 24-hour urine protein and pregnancy outcomes were recorded for pregnant F1 generation mice. Placental expressions of inflammatory (tumor necrosis factor-α, TNF-α; interleukin-6, IL-6; nuclear factor-κB, NF-κb) and apoptotic markers (Bcl-2 associated X protein, Bax, B-cell lymphoma/leukemia-2, Bcl-2, and Caspase-3) were evaluated via Western blot.

Results

Serum lipids, BP and 24-hour urine protein levels were shown to be significantly higher and parturition and placenta weights were lower in apoE^−/− and apoE^−/−iNOS^−/− groups (p<0.05). NO levels were lower in the apoE^−/−iNOS^−/− group. In addition, inflammatory/apoptosis parameters, including TNF-α, IL-6, NF-κb, Bax, Bcl-2 and Caspase-3 in the apoE^−/−iNOS^−/− group (p<0.01), as well as in the apoE^−/− group (p<0.05), and NF-κB, Bax in iNOS^−/− group (p<0.05) were higher compared with WT group. However, most of the inflammatory/apoptosis parameters in the iNOS^+/− and the apoE^+/− groups (p>0.05) showed no differences. In addition, placenta vascular endothelial and trophoblast cell morphological changes were demonstrated in both the apoE^−/−iNOS^−/− and apoE^−/− groups.

Conclusion

Elevated lipid metabolism and inflammatory/apoptosis parameters suggest a potentially significant role of apoE in preeclampsia pathology, as well as a relationship between iNOS and preeclampsia progression.

Effects of tea and coffee on cardiovascular disease risk

Tea and coffee have been associated with risk of cardiovascular disease (CVD), both positively and negatively. Epidemiological data suggest that black and green tea may reduce the risk of both coronary heart disease and stroke by between 10 and 20%. Experimental and clinical trial data generally indicate either neutral or beneficial effects on risk factors and pathways linked to the development of CVD. Controversy still exists regarding the effects of coffee, where there have been concerns regarding associations with hypercholesterolaemia, hypertension and myocardial infarction. However, long term moderate intake of coffee is not associated with detrimental effects in healthy individuals and may even protect against the risk of developing type 2 diabetes. The detrimental effects of coffee may be associated with the acute pressor effects, most likely due to caffeine at high daily intakes, and lipids from boiled coffee can contribute to raised serum cholesterol. Genetic polymorphisms in enzymes involved in uptake, metabolism and excretion of tea and coffee compounds are also associated with differential biological effects. Potential mechanisms by which tea and coffee phytochemicals can exert effects for CVD protection include the regulation of vascular tone through effects on endothelial function, improved glucose metabolism, increased reverse cholesterol transport and inhibition of foam cell formation, inhibition of oxidative stress, immunomodulation and effects on platelet function (adhesion and activation, aggregation and clotting). The phytochemical compounds in tea and coffee and their metabolites are suggested to influence protective endogenous pathways by modulation of gene-expression. It is not known exactly which compounds are responsible for the suggestive protective effects of tea and coffee. Although many biologically active compounds have been identified with known biological effects, tea and coffee contain many unidentified compounds with potential bioactivity.

Cerebral malaria: we have come a long way

Despite decades of research, cerebral malaria remains one of the most serious complications of Plasmodium infection and is a significant burden in Sub-Saharan Africa, where, despite effective antiparasitic treatment, survivors develop long-term neurological sequelae. Although much remains to be discovered about the pathogenesis of cerebral malaria, The American Journal of Pathology has been seminal in presenting original research from both human and experimental models. These studies have afforded significant insight into the mechanism of cerebral damage in this devastating disease. The present review highlights information gleaned from these studies, especially in terms of their contributions to the understanding of cerebral malaria.

Exogenous nitric oxide decreases brain vascular inflammation, leakage and venular resistance during Plasmodium berghei ANKA infection in mice

BACKGROUND

Cerebral malaria (CM) is a lethal complication of Plasmodium falciparum infections. In the Plasmodium berghei ANKA (PbA) murine model, CM is associated with marked brain inflammation, increased expression of endothelial cell adhesion molecules and leukocyte and platelet accumulation in brain vessels, causing vascular occlusion and decreased blood flow, damaging the endothelium and leading to blood-brain barrier breakdown, leakage and hemorrhages. Exogenous nitric oxide (NO) administration largely prevents the syndrome. Here we evaluated whether the mechanism of action of NO in preventing murine CM is related to its anti-inflammatory properties and to protection of the endothelium.

METHODS

C57Bl/6 mice infected with PbA were treated twice a day with saline or dipropylenetriamineNONOate (DPTA-NO). Endothelial cell adhesion molecule (ICAM-1, VCAM, E- and P-selectin) expression in brain tissue on day 6 of infection was assessed in both groups by western blot. For intravital microscopy studies, DPTA-NO-treated and saline-treated mice with a previously implanted closed cranial window were injected with albumin-FITC, anti-CD45-TxR and anti-CD41-FITC antibodies on day 6 of infection for quantification of albumin leakage, leukocyte and platelet adherence in pial vessels.

RESULTS

PbA-infected mice treated with the NO-donor DPTA-NO showed decreased expression of ICAM-1 and P-selectin, but not VCAM-1, in the brain, compared to saline-treated mice. DPTA-NO treatment also decreased the number of adherent leukocytes and platelets in pial vessels, particularly in venules 30-50 μm in diameter, decreased inflammatory vascular resistance and prevented the occurrence of arteriolar and venular albumin leakage observed in saline-treated PbA-infected mice, as assessed by intravital microscopy.

CONCLUSIONS

These results indicate that the protective effect of exogenous NO on murine CM is associated with decreased brain vascular expression of inflammatory markers resulting in attenuated endothelial junction damage and facilitating blood flow.

Effects of single-dose morning and evening administration of pravastatin on antioxidant markers in cholesterol-fed rabbits

BACKGROUND

Accurate timing of statin administration is considered important to obtain the best hypolipidemic effect. Pravastatin is one of the currently prescribed hepatic 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, and was chosen in this study to evaluate its antioxidant effect when administered as a single daily dose in the morning versus evening in cholesterol-fed rabbits.

METHODS

This 12-week study was performed in New Zealand rabbits, divided into four groups (n = 6 each), ie, normocholesterolemic controls; cholesterol 1% diet, nontreated ; cholesterol 1% diet treated with pravastatin in the morning; and cholesterol 1% diet treated with pravastatin in the evening. Plasma total cholesterol levels, superoxide dismutase enzyme levels in erythrocyte lysates, thiobarbituric acid-reactive substance content, catalase, and glutathione enzyme activity in liver homogenates from the tested rabbits were measured.

RESULTS

Both morning and evening treatment with pravastatin significantly improved all the measured antioxidant markers in comparison with nontreated cholesterol-fed rabbits. However, results obtained with evening dosing were better than with morning dosing.

CONCLUSION

The antioxidant profile of pravastatin is better when the drug is administered in the evening rather than in the morning.

Strawberries decrease atherosclerotic markers in subjects with metabolic syndrome

Strawberries have been reported to be potent antioxidants and reduce cardiovascular risk factors, such as elevated blood pressure, hyperglycemia, dyslipidemia, and inflammation in limited studies. We hypothesized that freeze-dried strawberry supplementation will improve blood pressure, impaired glucose, dyslipidemia, or circulating adhesion molecules in obese subjects with metabolic syndrome, thereby lowering cardiovascular risk factors in these subjects. Twenty-seven subjects with metabolic syndrome (2 males and 25 females; body mass index, 37.5 +/- 2.15 kg/m(2); age, 47.0 +/- 3.0 years [means +/- SE]) consumed 4 cups of freeze-dried strawberry beverage (50 g freeze-dried strawberries approximately 3 cups fresh strawberries) or equivalent amounts of fluids (controls, 4 cups of water) daily for 8 weeks in a randomized controlled trial. Anthropometrics and blood pressure measurements, assessment of dietary intakes, and fasting blood draws were conducted at screen and 8 weeks of the study. Strawberry supplementation significantly decreased total and low-density lipoprotein cholesterol (5.8 +/- 0.2 to 5.2 +/- 0.2 mmol/L and 3.5 +/- 0.2 to 3.1 +/- 0.1 mmol/L, respectively [means +/- SE], P < .05) and small low-density lipoprotein particles using nuclear magnetic resonance-determined lipoprotein subclass profile vs controls at 8 weeks (794.6 +/- 94.0 to 681.8 +/- 86.0 nmol/L [means +/- SE], P < .05). Strawberry supplementation further decreased circulating levels of vascular cell adhesion molecule-1 vs controls at 8 weeks (272.7 +/- 17.4 to 223.0 +/- 14.0 ng/mL [means +/- SE], P < .05). Serum glucose, triglycerides, high-density lipoprotein cholesterol, blood pressure, and waist circumference were not affected. Thus, short-term freeze-dried strawberry supplementation improved selected atherosclerotic risk factors, including dyslipidemia and circulating adhesion molecules in subjects with metabolic syndrome, and these results need confirmation in future trials.

Hypercholesterolemia and microvascular dysfunction: interventional strategies

Hypercholesterolemia is defined as excessively high plasma cholesterol levels, and is a strong risk factor for many negative cardiovascular events. Total cholesterol levels above 200 mg/dl have repeatedly been correlated as an independent risk factor for development of peripheral vascular (PVD) and coronary artery disease (CAD), and considerable attention has been directed toward evaluating mechanisms by which hypercholesterolemia may impact vascular outcomes; these include both results of direct cholesterol lowering therapies and alternative interventions for improving vascular function. With specific relevance to the microcirculation, it has been clearly demonstrated that evolution of hypercholesterolemia is associated with endothelial cell dysfunction, a near-complete abrogation in vascular nitric oxide bioavailability, elevated oxidant stress, and the creation of a strongly pro-inflammatory condition; symptoms which can culminate in profound impairments/alterations to vascular reactivity. Effective interventional treatments can be challenging as certain genetic risk factors simply cannot be ignored. However, some hypercholesterolemia treatment options that have become widely used, including pharmaceutical therapies which can decrease circulating cholesterol by preventing either its formation in the liver or its absorption in the intestine, also have pleiotropic effects with can directly improve peripheral vascular outcomes. While physical activity is known to decrease PVD/CAD risk factors, including obesity, psychological stress, impaired glycemic control, and hypertension, this will also increase circulating levels of high density lipoprotein and improving both cardiac and vascular function. This review will provide an overview of the mechanistic consequences of the predominant pharmaceutical interventions and chronic exercise to treat hypercholesterolemia through their impacts on chronic sub-acute inflammation, oxidative stress, and microvascular structure/function relationships.

Endothelial activation, inflammation and premature atherosclerosis in children with familial dyslipidemia

OBJECTIVES

Prospective studies demonstrated an increased cardiovascular risk in subjects with high levels of either the endothelial-platelet activation marker P-selectin or high-sensitivity C-reactive protein (hs-CRP). Both children with heterozygous familial hypercholesterolemia (FH) and those with familial combined hyperlipidemia (FCHL) are prone to premature atherosclerosis. Our objective was to investigate in children with either FH or FCHL whether P-selectin and hs-CRP contribute to carotid intima-media thickness (IMT), along with increased plasma lipid levels.

METHODS

Carotid IMT, serum lipids and soluble P-selectin and hs-CRP levels were measured in 88 children (mean age 10.5+/-4.3 years) including 44 dyslipidemic children (25 with FH and 19 with FCHL) and 44 non-dyslipidemic controls.

RESULTS

Carotid IMT was significantly higher among dyslipidemic than in control children (0.46+/-0.06mm vs 0.43+/-0.06mm, p=0.003) and serum P-selectin levels as well [129(50-254)ng/mL vs 50(24.5-130)ng/mL, p<0.001]. FH but not FCHL children had higher hs-CRP levels than controls [0.7(0.01-6.9)mg/L vs 0.3(0.1-1.2)mg/L, p=0.006]. In the entire sample of dyslipidemic children, carotid IMT was positively associated with soluble P-selectin levels (rho=0.30, p=0.049), but not with hs-CRP. The association between P-selectin and carotid IMT was independent from confounders, including plasma lipid levels.

CONCLUSION

Endothelial-platelet activation, more than low-grade systemic inflammation, correlates with premature atherosclerosis among children with familial dyslipidemia, this association being independent from plasma lipid levels.

Role of NADPH oxidase in atherosclerosis

Reactive oxidant species (ROS) seem to play a key role in the atherosclerotic process via a series of molecular changes that lead to macrophage infiltration in the endothelium and eventually to plaque formation. ROS are also implicated in arterial dysfunction via inactivation of nitric oxide, a potent vasodilator and antiaggregating molecule produced by the endothelium. Owing to the relevance of endothelial dysfunction and vascular inflammation in the process of human atherosclerosis, a lot of effort has been directed towards discovering the ROS-generating pathways implicated in the ROS upregulation. Amongst the enzymatic pathways, NADPH oxidase is the most important enzyme responsible for ROS formation in human vessels. Experimental and clinical studies suggested a role for this enzyme in initiation and progression of atherosclerotic disease. The purpose of this review is to analyze whether the basic and clinical studies are consistent with this hypothesis and to point out if determination of NADPH oxidase is useful in the setting of the atherosclerosis to predict its progression and clinical complications.

Video-rate two-photon imaging of mouse footpad - a promising model for studying leukocyte recruitment dynamics during inflammation

Leukocyte recruitment is a key host defense mechanism to infection and a salient feature of autoimmune diseases such as arthritis. The cell dynamics of these processes are difficult to study due to the challenge of tracking cells flowing in the circulation and migrating through light scattering tissues. Here, we describe a noninvasive two-photon (2P) microscopy approach to study leukocyte homing in the mouse footpad. In the absence of inflammation, cells moved > several hundred microm/s in vessels and only rarely adhered to endothelium or entered the tissue parenchyma. In response to bacterial infection, neutrophils moved in small capillaries at reduced speeds of (14-45 microm/min) and rolled in larger vessels at 5-60 microm/min. Within minutes of adoptive transfer, neutrophils entered the connective tissue and crawled with a median velocity of 7.3 microm/min. 2P imaging has excellent spatiotemporal resolution and is a promising in vivo approach to study the cellular basis of inflammation.

Platelet-associated NAD(P)H oxidase contributes to the thrombogenic phenotype induced by hypercholesterolemia

Elevated cholesterol levels promote proinflammatory and prothrombogenic responses in venules and impaired endothelium-dependent arteriolar dilation. Although NAD(P)H oxidase-derived superoxide has been implicated in the altered vascular responses to hypercholesterolemia, it remains unclear whether this oxidative pathway mediates the associated arteriolar dysfunction and platelet adhesion in venules. Platelet and leukocyte adhesion in cremasteric postcapillary venules and arteriolar dilation responses to acetylcholine were monitored in wild-type (WT), Cu,Zn-superoxide dismutase transgenic (SOD-TgN), and NAD(P)H oxidase-knockout (gp91(phox-/-)) mice placed on a normal (ND) or high-cholesterol (HC) diet for 2 weeks. HC elicited increased platelet and leukocyte adhesion in WT mice versus ND. Cytosolic subunits of NAD(P)H oxidase (p47phox and p67phox) were expressed in platelets. This was not altered by hypercholesterolemia; however, platelets and leukocytes from HC mice exhibited elevated generation of reactive oxygen species compared to ND mice. Hypercholesterolemia-induced leukocyte recruitment was attenuated in SOD-TgN-HC and gp91(phox-/-)-HC mice. Recruitment of platelets derived from WT-HC mice in venules of SOD-TgN-HC or gp91(phox-/-)-HC recipients was comparable to ND levels. Adhesion of SOD-TgN-HC platelets paralleled the leukocyte response and was attenuated in SOD-TgN-HC recipients, but not in WT-HC recipients. However, gp91(phox-/-)-HC platelets exhibited low levels of adhesion comparable to those of WT-ND in both hypercholesterolemic gp91(phox-/-) and WT recipients. Arteriolar dysfunction was evident in WT-HC mice, compared to WT-ND. Overexpression of SOD or, to a lesser extent, gp91(phox) deficiency restored arteriolar vasorelaxation responses toward WT-ND levels. These findings reveal a novel role for platelet-associated NAD(P)H oxidase in producing the thrombogenic phenotype in hypercholesterolemia and demonstrate that NAD(P)H oxidase-derived superoxide mediates the HC-induced arteriolar dysfunction.

Enzymes that hydrolyze adenine nucleotides of patients with hypercholesterolemia and inflammatory processes

The activity of NTPDase (EC 3.6.1.5, apyrase, CD39) was verified in platelets from patients with increasing cholesterol levels. A possible association between cholesterol levels and inflammatory markers, such as oxidized low-density lipoprotein, highly sensitive C-reactive protein and oxidized low-density lipoprotein autoantibodies, was also investigated. Lipid peroxidation was estimated by measurement of thiobarbituric acid reactive substances in serum. The following groups were studied: group I, < 150 mg.dL(-1) cholesterol; group II, 151-200 mg.dL(-1) cholesterol; group III, 201-250 mg.dL(-1) cholesterol; and group IV, > 251 mg.dL(-1) cholesterol. The results demonstrated that both ATP hydrolysis and ADP hydrolysis were enhanced as a function of cholesterol level. Low-density lipoprotein levels increased concomitantly with total cholesterol levels. Triglyceride levels were increased in the groups with total cholesterol above 251 mg.dL(-1). Oxidized low-density lipoprotein levels were elevated in groups II, III, and IV. Highly sensitive C-reactive protein was elevated in the group with cholesterol levels higher than 251 mg.dL(-1). Oxidized low-density lipoprotein autoantibodies were elevated in groups III and IV. Thiobarbituric acid reactive substance content was enhanced as a function of cholesterol level. In summary, hypercholesterolemia is associated with enhancement of inflammatory response, oxidative stress, and ATP and ADP hydrolysis. The increased ATP and ADP hydrolysis in group IV was confirmed by an increase in CD39 expression on its surface. The increase in CD39 activity is possibly related to a compensatory response to the inflammatory and pro-oxidative state associated with hypercholesterolemia.

Protective effect of lupeol and its ester on cardiac abnormalities in experimental hypercholesterolemia

Hyperlipidemia is a major risk factor for the premature development of coronary heart disease and it has been shown to increase the incidence of myocardial ischemia and cardiac events. Pentacyclic triterpenes possess antiatherosclerotic, antioxidant, anti-inflammatory and cytoprotective effects. To study the effect of plant derived triterpene, lupeol and its ester lupeol linoleate, on lipid status and biochemical changes on heart tissue, male albino Wistar rats were fed high-cholesterol diet (normal rat chow supplemented with 4% cholesterol and 1% cholic acid; HCD) for 30 days. There was a significant (p<0.001) increase in the levels of total cholesterol, triglycerides and phospholipids along with augmented activities of lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase in the heart tissue. Triterpenes treatment reduced the above alterations produced in hypercholesterolemic rats. The transmembrane enzymes, namely Na(+), K(+)-ATPase, Ca(2+)-ATPase and Mg(2+)-ATPase showed a decrease in their activities. Triterpenes treatment reversed these levels, prevented the hypertrophic cardiac histology and restored the normal ultrastructural architecture. In conclusion, lupeol and lupeol linoleate intervention minimized the lipid abnormalities and abnormal biochemical changes induced by HCD fed rats. This shows that triterpenes possess cardioprotective effects which will be beneficial in hypercholesterolemic condition. Out of these two triterpenes tested, lupeol linoleate appeared to be even more effective than lupeol.

Arginine uptake is attenuated, through post-translational regulation of cationic amino acid transporter-1, in hyperlipidemic rats

Endothelial cell dysfunction (ECD) is a common feature of hypercholesterolemia. Defective nitric oxide (NO) generation due to decreased endothelial nitric oxide synthase (eNOS) activity is a crucial parameter characterizing ECD. L-arginine is the sole precursor for NO biosynthesis. Among several transporters that mediate L-arginine uptake, cationic amino acid transporter-1 (CAT-1) acts as a specific arginine transporter for eNOS. Our hypothesis implies that CAT-1 is a major determinant of eNOS activity in hypercholesterolemia. We studied aortic arginine uptake, CAT-1 and CAT-2 mRNA expression, and CAT-1, and PKC alpha protein in: (a) control, untreated animals (CTL), (b) rats fed with 4% cholesterol+1% cholate and 2% corn oil for 6 weeks (CHOL) and (c) rats with hypercholesterolemia treated orally with either atorvastatin (CHOL+ATORVA, 20mg/kg BW/day) or arginine 1% (CHOL+ARG) in the drinking water (modalities which have been shown to enhance CAT-1 activity and improve endothelial function). Serum cholesterol levels significantly increased in cholesterol fed animals, an increase which was blocked by atorvastatin (CTL: 66.8+/-15, CHOL: 133.9+/-22, CHOL+ARG: 128.2+/-20, CHOL+ATORVA: 77+/-15 mg/dl). Arginine transport was significantly decreased in CHOL. Treatment with neither arginine nor atorvastatin had an effect. Using RT-PCR, we found no change in aortic CAT-1 and CAT-2 mRNA expression in CHOL as well as following arginine or atorvastatin administration. The abundance of CAT-1 protein was significantly augmented in cholesterol fed rats and was not affected by arginine or atorvastatin. PKC alpha protein content, which was previously shown to regulate CAT-1 activity, increased significantly in CHOL and was neither affected by atorvastatin nor arginine. In conclusion, aortic arginine uptake is attenuated in hypercholesterolemia, through post-translational modulation of CAT-1 protein, possibly via upregulation of PKC alpha.

Mediators of CD18/P-selectin-dependent constriction of venule-paired arterioles in hypercholesterolemia

This study addresses the role of venule-derived mediators in the arteriolar constriction that accompanies hypercholesterolemia. Constriction was assessed by measuring the tone of small arterioles closely paired with venules in the mesentery of normal cholesterol rats (NC), high cholesterol rats (HC), HC rats injected with antibodies against CD18 and P-selectin (HC/mAbs), HC rats treated with the thromboxane synthase inhibitor, ozagrel (HC/ozagrel), and HC rats pretreated with anti-platelet serum (HC/APS). Venule-paired arterioles in the untreated HC group demonstrated enhanced tone compared with arterioles in the NC group, while no difference was found between unpaired arterioles of the two groups. Perivascular nitric oxide (NO) concentrations were found to be significantly decreased in venule-paired arterioles of HC rats (238+/-14 nM) compared with those of NC rats (426+/-42 nM). The injection of anti-adhesion antibodies successfully attenuated the enhanced arteriolar tone and venular leukocyte adherence in the HC group, and tended to increase levels of NO in venule-paired arterioles by 33% (to 326+/-19 nM; still lower than that of the NC group). Ozagrel and platelet depletion attenuated the enhanced arteriolar tone by 53% and 33%, respectively, without affecting NO concentrations. These findings indicate that the mechanism of blood cell-dependent arteriolar constriction during hypercholesterolemia may be dependent on thromboxane, a decrease in NO, and the proximity of the arterioles to postcapillary venules.

Prothrombotic factors enhance heparin-induced thrombocytopenia and thrombosis in vivo in a mouse model

BACKGROUND

Heparin-induced thrombocytopenia/thrombosis (HIT/T) is a common cause of life- and limb-threatening thrombosis. The development of antibodies that react with complexes of heparin and platelet factor 4 (PF4) is fundamental to the development of the disease. However, anti-PF4/heparin antibodies are far more common than is HIT/T and there is less understanding of the factors that contribute to thrombosis in only a subset of patients.

OBJECTIVES

Both qualitative and quantitative differences in multiple factors (e.g. antibodies, heparin and platelets) may influence the clinical course of patients who develop anti-PF4/heparin antibodies. We examined the hypothesis that host-specific factors, such as comorbid prothrombotic conditions, would exacerbate the pathologic effects of anti-PF4/heparin antibodies.

METHODS AND RESULTS

A mouse model transgenic for human Fcgamma RIIa and PF4 and null for mouse PF4 was used to study the influence of prothrombotic conditions on the effects of anti-PF4/heparin antibodies in vivo. To simulate a prothrombotic milieu, mice were fed a hypercholesterolemic diet (HD). HD-fed mice had elevated plasma cholesterol, increased platelet reactivity and increased endothelial activation relative to mice fed a standard diet (SD). Age- and sex-matched mice from each diet group were treated with an anti-PF4/heparin antibody and heparin. HD-fed mice developed more severe thrombocytopenia than similarly treated SD-fed mice. Mice with moderate to severe thrombocytopenia had elevated plasma levels of thrombin-antithrombin complexes, indicative of increased thrombin generation in vivo. Platelet-fibrin thrombi were observed in multiple organs of HD-fed mice that developed severe thrombocytopenia.

CONCLUSIONS

Host-specific factors, such as prothrombotic changes in platelet reactivity and/or endothelial activation, may influence the development of thrombosis in a subset of patients who develop anti-PF4/heparin antibodies.

P-selectin-mediated adhesion impairs endothelium-dependent arteriolar dilation in hypercholesterolemic mice

Hypercholesterolemia is associated with an attenuation of endothelium-dependent dilation in arterioles and an increase in leukocyte and platelet adhesion in venules. The proximity of closely paired arterioles and venules is thought to facilitate heat and mass transport between the two and could be involved in transport of inflammatory and/or vasoactive mediators from venule to arteriole. In the current study, we tested the hypothesis that the impaired arteriolar dilation associated with hypercholesterolemia might be dependent on P-selectin-dependent blood cell adhesion in the closely paired venules. Leukocyte and platelet recruitment in venules and the endothelium-dependent response to bradykinin in second-order arterioles were observed in the mouse intestinal submucosa using intravital microscopy. Four weeks of a high-cholesterol diet decreased bradykinin-induced arteriolar dilation more dramatically in closely paired arterioles than in distantly paired arterioles. The dysfunctional arteriolar dilation of closely paired arterioles in hypercholesterolemic mice was significantly improved when the experiments were repeated in P-selectin-deficient mice (given the high-cholesterol diet) or in hypercholesterolemic mice injected with a P-selectin monoclonal antibody. A similar improvement in dilation of closely paired arterioles was attained in hypercholesterolemic mice given the superoxide dismutase mimetic Tempol. These findings indicate that hypercholesterolemia-induced increases in venular leukocyte and platelet adhesion might contribute to the impaired endothelium-dependent dilation of closely paired arterioles via a mechanism that is distance limited and dependent on P-selectin and superoxide.

ICAM-1 expression in adipose tissue: effects of diet-induced obesity in mice

Obesity has been linked to cardiovascular disease, hypertension, diabetes and the metabolic syndrome, with elevated markers of systemic inflammation. Intercellular adhesion molecule-1 (ICAM-1) is a transmembrane adhesion molecule involved in leukocyte migration to sites of inflammation. In human obesity, elevated expression of the soluble form of ICAM-1 (sICAM-1) is positively correlated with abdominal fat deposition. Increases in adiposity have also been correlated with macrophage infiltration into adipose tissue. Here we investigate adipose tissue production and transcriptional regulation of ICAM-1 in a mouse model of dietary obesity. After feeding mice a high-fat diet, ICAM-1 expression in serum and adipose tissue was analyzed by ELISA, Northern blotting, real-time quantitative PCR, and flow cytometry. After 6 mo on the high-fat diet, sICAM-1 levels significantly correlated with body weight and abdominal fat mass. ICAM-1 mRNA was expressed in adipose tissue of mice, with significantly higher levels in males than females. After only 3 wk, there were adipose tissue-specific increases in mRNAs for ICAM-1, IL-6, and monocyte chemoattractant protein-1 (MCP-1) in male mice. Analysis of the stromal-vascular fraction of male adipose tissue revealed CD11b-negative cells with increased surface ICAM-1 and CD34. We also found two populations of F4/80+, CD11b+, ICAM-1+ cells, one of which also expressed CD14 and CD11c and was increased in response to a high-fat diet. These results indicate that within 3 wk on a high-fat diet, male mice exhibited significant increases in pro-inflammatory factors and immune cell infiltration in adipose tissue that may represent links between obesity and its associated inflammatory complications.

Hypercholesterolemia is a potential risk factor for asthma

INTRODUCTION

The effect of hyperlipidemia on asthma has never been addressed. Recent literature implicates a pro-inflammatory role for hypercholesterolemia. This study evaluates the effect of serum cholesterol level on asthma frequency.

METHODS

Factors associated with asthma risk were examined in a retrospective study design. Study subjects were between the 4 and 20 years of age who presented to a rural pediatric clinic and whose total serum cholesterol level was obtained. Diagnosis of asthma was determined by the treating physician. Multivariable logistic regression was performed to identify variables that were related to the odds of having asthma.

RESULTS

A total of 188 patients were included. Asthma was present in 50 patients. Total serum cholesterol (mean +/- SD) for the asthma group was 176.7 +/- 39.8 compared to 162.9 +/- 12.8 in the non-asthma group (P = 0.028). A total of 21 of the 50 (42%) asthma patients were obese compared to 31 of the 138 (22%) non-asthma patients (p = 0.014). There was no difference between both groups regarding age and gender. Hypercholesterolemia and obesity were identified by logistic regression analysis to increase the probability of asthma independently.

CONCLUSION

Hypercholesterolemia is a potential risk factor for asthma independent of obesity.

Favourable modulation of the inflammatory changes in hypercholesterolemic atherogenesis by a low-molecular-weight heparin derivative

BACKGROUND

In the hypercholesterolemic state, the net result of combined oxidative and nitrosative stress is a pro-inflammatory phenotype that is manifested as increased adhesion molecule expression, enhanced leucocyte trafficking, and increased vascular permeability. The present work explores the inflammatory aspects of hypercholesterolemic atherogenesis, and also evaluates the role of a low-molecular-weight heparin derivative (LMWH), Certoparin, on a biochemical basis.

METHODS AND RESULTS

Two groups of male Wistar rats were fed an atherogenic diet (normal rat chow plus 4% cholesterol, 1% cholic acid and 0.5% thiouracil-CCT diet) for 2 weeks. While one was left untreated, the other was administered LMWH (300 microg/day/rat commencing on day 8 and continued for a week). Increased concentrations of plasma C-reactive protein and fibrinogen and cardiac TNF-alpha indicated severe inflammation in the atherogenic diet fed rats. In comparison, these biochemical indices of inflammation diminished significantly in the LMWH treated group (p < 0.001). Significant depletion of thiols, along with accentuated activities of the glutathione metabolising was observed in the cardiac and hepatic tissues of the untreated atherogenic rats, indicating heightened oxidative response. Tissue damage was marked by elevated levels of plasma and tissue hexose, hexosamine, hexuronic acid and sialic acid, which were reversed towards normalcy on LMWH administration. The activities of lysosomal enzymes (N-acetyl glucosaminidase, beta-glucuronidase, beta-galactosaminidase and cathepsin-D) showed a marked increase in the CCT-diet fed rats, while LMWH treated rats showed normal activities (p < 0.001). The osmotic fragility test revealed that the untreated hyperlipidemic rat erythrocytes were significantly fragile at high salt concentrations, while the response was normalized in the LMWH treated group (p < 0.05). Further, hypercholesterolemia induced downregulation of physiological nitric oxide levels was corrected upon treatment with heparin-derivative.

CONCLUSION

The results of this work highlight the inflammatory changes in atherogenic conditions and that the low-molecular-weight heparin derivative affords substantial protection.

Pathogen-accelerated atherosclerosis occurs early after exposure and can be prevented via immunization

Here we report on early inflammatory events associated with Porphyromonas gingivalis-accelerated atherosclerosis in apolipoprotein E knockout (ApoE-/-) mice. Animals challenged with P. gingivalis presented with increased macrophage infiltration, innate immune marker expression, and atheroma without elevated systemic inflammatory mediators. This early local inflammatory response was prevented in mice immunized with P. gingivalis. We conclude that localized up-regulation of innate immune markers early after infection, rather than systemic inflammation, contributes to pathogen-accelerated atherosclerosis.

Dyslipidaemia and microvascular disease in the retina

PURPOSE

There are few data on the effect of serum lipids on microvascular disease. This study assessed the relationships between serum lipid levels and microvascular disease, as seen in the retina, among participants who attended a population-based study in Australia (n=3654, aged 49+years).

METHODS

Diameters of retinal arterioles and venules were measured from digitised photographs of each participant to obtain an estimate of generalised arteriolar narrowing. Focal arteriolar narrowing, arteriovenous nicking, and retinopathy lesions (microaneurysms, haemorrhages, hard/soft exudates) were graded using a standard protocol. Fasting blood tests were performed in 89% of subjects. Adjusted means were calculated using general linear models. Logistic regression models were used to determine the odds ratios for retinal microvascular signs.

RESULTS

After controlling for age, sex, body mass index, smoking, and mean arterial blood pressure, elevated high-density lipoprotein cholesterol was associated with narrower retinal arterioles (Ptrend=0.002) and venules (Ptrend=0.03) and with increased odds of generalised arteriolar narrowing (odds ratio 1.6, 95% confidence interval 1.1-2.2 for the highest vs the lowest quintile of high-density lipoprotein cholesterol). Serum triglyceride had a U-shaped relationship with venular diameter (Ptrend=0.003). We found no consistent pattern of association between serum total cholesterol or low-density lipoprotein cholesterol and any retinal microvascular signs.

CONCLUSIONS

These findings suggest that microvascular disease in the retina may result from processes distinct from dyslipidaemia.

Hypercholesterolemia, not metabolic syndrome, related to adhesion of monocytes to cultured endothelium in nondiabetic subjects

The interaction of leukocytes and endothelium plays an important role in the development of atherosclerosis. Previous studies found that adhesion of leukocytes to endothelium is greater in subjects with hypercholesterolemia. It is not clear if metabolic syndrome, a contributing risk factor of cardiovascular disease, is related to this adhesion. Therefore, we conducted a study, in which 48 nondiabetic subjects were enrolled, to determine the relationship between leukocyte adhesion and the components of metabolic syndrome. After a 12-hour overnight fast, subjects' fasting blood was obtained for measurement of lipoprotein concentrations and glucose and insulin levels. Results of the number of monocyte adhesion to human umbilical vein endothelial cells were divided into high monocyte adhesion group and low monocyte adhesion group (n=24 in each group). Plasma concentrations of total cholesterol (245 +/- 5 vs 229+/- 4 mg/dL, P=.021) and low-density lipoprotein cholesterol (LDL-C) (162+/- 4 vs 146+/- 3 mg/dL, P=.003) were both higher in the high monocyte adhesion group than in the low monocyte adhesion group. Monocyte adhesion was significantly correlated to plasma concentrations of LDL-C (r=0.407, P=.002) but not to the total cholesterol (r=0.202, P=.085). However, there was no difference in monocyte adhesion to endothelium between subjects with or without metabolic syndrome, based on the modified criteria from the Adult Treatment Panel III of the National Cholesterol Education Program. Insulin resistance index, presented as homeostasis model assessment insulin resistance, and glucose or insulin responses to oral glucose tolerance test were similar between groups. Our study demonstrated that monocyte adhesion to endothelium has a stronger relationship with the plasma concentration LDL-C than with characteristics of metabolic syndrome.

Porphyromonas gingivalis fimbria-dependent activation of inflammatory genes in human aortic endothelial cells

Epidemiological and pathological studies have suggested that infection with the oral pathogen Porphyromonas gingivalis can potentiate atherosclerosis and human coronary heart disease. Furthermore, infection with invasive, but not noninvasive P. gingivalis has been demonstrated to accelerate atherosclerosis in apolipoprotein E-deficient (ApoE(-/-)) mice and to accelerate local inflammatory responses in aortic tissue. In the present study, using high-density oligonucleotide microarrays, we have defined the gene expression profile of human aortic endothelial cells (HAEC) after infection with invasive and noninvasive P. gingivalis. After infection of HAEC with invasive P. gingivalis strain 381, we observed the upregulation of 68 genes. Genes coding for the cytokines Gro2 and Gro3; the adhesion molecules intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule (VCAM)-1, and ELAM-1 (E-selectin); the chemokine interleukin-8 (IL-8); and the proinflammatory molecules IL-6 and cyclooxygenase-2 were among the most highly upregulated genes in P. gingivalis 381-infected HAEC compared to uninfected HAEC control. Increased mRNA levels for signaling molecules, transcriptional regulators, and cell surface receptors were also observed. Of note, only 4 of these 68 genes were also upregulated in HAEC infected with the noninvasive P. gingivalis fimA mutant. Reverse transcription-PCR, enzyme-linked immunosorbent assay, and fluorescence-activated cell sorting analysis confirmed the expression of ICAM-1, VCAM-1, E-/P-selectins, IL-6, and IL-8 in HAEC infected with invasive P. gingivalis. We also demonstrated that increased expression of ICAM-1 and VCAM-1 in aortic tissue of ApoE(-/-) mice orally challenged with invasive P. gingivalis but not with the noninvasive P. gingivalis fimA mutant by immunohistochemical analysis. Taken together, these results demonstrate that P. gingivalis fimbria-mediated invasion upregulates inflammatory gene expression in HAEC and in aortic tissue and indicates that invasive P. gingivalis infection accelerates inflammatory responses directly in the aorta.

Systemic inflammatory markers in acute coronary syndrome: association with cardiovascular risk factors and effect of early lipid lowering

BACKGROUND

Evidence for statin therapy in prevention of coronary artery disease is overwhelming. In spite of theoretical benefits, any additional advantage of its early introduction in the management of acute coronary syndrome is, however, uncertain. We therefore investigated differences between plasma levels of the systemic inflammatory markers intercellular adhesion molecule-1, vascular cell adhesion molecule-1, E-selectin, C-reactive protein and interleukin-6 in patients presenting with unstable angina or acute myocardial infarction, and assessed whether the 30-day levels of these markers are influenced by early instigation of the HMG-CoA reductase inhibitor pravastatin.

MATERIALS AND METHODS

170 (134 male) patients presenting with acute coronary syndrome, but without previous statin therapy, participated. Blood was taken within 24 h of onset of ischaemic pain and again at 30 days. In all, 87 (71 male) participants were treated with pravastatin (20-40 mg daily) and 83 (63 male) with a matched placebo.

RESULTS

At presentation, interleukin-6 was higher in males than in females (P=0.008) and lower in those with a pre-existing history of myocardial infarction (P=0.038). C-reactive protein and interleukin-6 were greater in myocardial infarction, but this difference was lost at 30 days. Thirty-day changes in all parameters were inversely related to level at presentation but not to treatment with pravastatin. Hypertension (P=0.011) and smoking (P=0.042) were associated with elevation of C-reactive protein with no difference between unstable angina or acute myocardial infarction. The effect of these individual factors was cumulative.

CONCLUSIONS

Interleukin-6 was greater in acute myocardial infarction than in unstable angina; E-selectin was positively associated with a previous myocardial infarction and inversely related to age. We found no effect of early introduction of pravastatin on systemic inflammatory markers 30 days after acute coronary syndrome.

Anti-inflammatory inhibition of endothelial cell adhesion molecule expression by flavone derivatives

Endothelial expression of cell adhesion molecules (CAM) including VCAM-1, E-selectin, and PECAM-1 plays a leading role in atherosclerosis. Phenolic flavones have been shown to have an anti-inflammatory property. This study examines whether 3',4'-dimethoxy-7-hydroxyflavone (methoxyflavone) and 2',3',7-trihydroxyflavone (hydroxyflavone) inhibited monocyte adhesion to TNF-alpha-activated endothelium via reduction of CAM expression in human umbilical vein endothelial cells (HUVEC). In stimulated HUVEC the expression of VCAM-1 and E-selectin was enhanced with increasing mRNA levels. Methoxyflavone markedly interfered with the THP-1 monocyte adhesion to TNF-alpha-stimulated HUVEC. At concentrations of > or =25 microM, methoxyflavone blocked the induction of VCAM-1 but not that of E-selectin on the activated HUVEC. Immunocytochemical staining showed that methoxyflavone modestly inhibited PECAM-1 expression induced by TNF-alpha. In contrast, hydroxyflavone minimally inhibited TNF-alpha-stimulated E-selectin expression without affecting VCAM-1 level. The inhibitory effect of methoxyflavone on THP-1 adhesion to HUVEC appears to be greater than that of hydroxyflavone, most likely due to a greater inhibition of CAM expression. Thus, some flavone derivatives containing methoxy groups may have therapeutic potential attenuating inflammatory response-related atherosclerosis.