Prediction of Acute Glomerular Filtration Rate Reductions Following Renin-angiotensin System Blockade in Chronic Kidney Disease: A Possible Application of Ultrasonography in Clinical Practice

Objective Renal arteriolosclerosis is a risk factor for acute reductions in the glomerular filtration rate (GFR) when renin-angiotensin system (RAS) inhibitors are administered. Renal arteriolosclerosis can be detected by an increase in the resistive index (RI) on Doppler ultrasonography. The purpose of the present study is to determine whether or not the RI can predict acute GFR reductions following RAS blockade in chronic kidney disease (CKD). Methods We surveyed all CKD patients who were hospitalized in Otemae Hospital from January 2008 to December 2017. One hundred and eight patients who had been newly treated with RAS inhibitors were able to be followed for 14 weeks. The end point was an acute reduction in the GFR, defined as a decrease of ≥30%. Results Twenty-three of the 108 patients presented with acute GFR reductions. The cumulative probability of acute GFR reductions was 3.3% and 53% in patients with RI ≤0.70 and RI >0.70, respectively (p<0.001). A univariate Cox proportional-hazards analysis showed that the RI, age, GFR, systolic blood pressure, urinary protein excretion, diabetic kidney disease, coronary artery disease, and use of diuretics were significant variables. Multivariate hazard ratios were calculated from the RI and three established variables (age, GFR, diuretics), and the RI and use of diuretics were shown to be significant risk factors for acute GFR reductions. Conclusion These results suggest that an increase in the RI, as well as the use of diuretics, may be risk factors for acute GFR reductions following RAS blockade.

Potential Effects of Desalinated Seawater on Arteriosclerosis in Rats

To evaluate the potential risk of arteriosclerosis caused by desalinated seawater, Wistar rats were provided desalinated seawater over a 1-year period, and blood samples were collected at 0, 90, 180, and 360 days. Blood calcium, magnesium, and arteriosclerosis-related indicators were investigated. Female rats treated with desalinated seawater for 180 days showed lower magnesium levels than the control rats (P < 0.05). The calcium and magnesium levels in female rats and the magnesium level in male rats were lower than the levels in the controls, following treatment with desalinated seawater for 360 days (P < 0.05). Blood levels of arteriosclerosis-related lipid peroxidation indicators and C-reactive protein (CRP) in the treatment group did not differ from those in the controls. The levels of lipid peroxidation indicators and CRP in rats were not significantly affected by drinking desalinated seawater, and no increase in risk of arteriosclerosis was observed.

Clinical Search for Undiagnosed Mesenteric Phlebosclerosis at Outpatient Departments Specializing in Herbal (Kampo) Medicine

OBJECTIVE

Mesenteric phlebosclerosis (MP) is a disease characterized by calcification of the mesenteric vein, which causes chronic mesenteric ischemia. Recently, the long-term intake of gardenia fruit ('Sanshishi' in Japanese) has been attracting attention as a possible cause. Usually, only advanced, severe MP cases get reported. However, we suspected that some latent cases of this disease may exist. We performed this study in order to determine the prediagnostic cases at our outpatient departments of herbal (Kampo) medicine, with particular attention paid to the initial changes, such as any slight color change of the colon, as shown in colonoscopy.

METHODS

We recommend colonoscopy and computed tomography (CT) scans for patients with a long-term history of taking herbal medicines containing gardenia fruit. Clinical examinations were performed upon receiving patients' consent from December 2013 to November 2014.

RESULTS

Of the 103 patients who took gardenia fruit long-term, 29 agreed to be checked for MP. 14 patients underwent colonoscopy. Four patients were confirmed to have MP due to the presence of fibrotic deposition of the colonic membrane on histological inspection. Twenty-one patients underwent abdominal CT screening. Characteristic calcification of the mesenteric vein was observed on CT scans in 2 patients. All 4 MP patients took Kampo formulas containing gardenia fruit for more than 6.8 years. The other patients did not develop MP, despite long-term gardenia fruit intake.

CONCLUSION

We detected the latent and undiagnosed MP cases. All diagnoses were made while paying careful attention to any slight changes in colonoscopy and CT scans.

The changes in the endothelial expression of cell adhesion molecules and iNOS in the vessel wall after the short-term administration of simvastatin in rabbit model of atherosclerosis

Cell adhesion molecules P-selectin, VCAM-1 and ICAM-1 play an important role in the pathogenesis of atherosclerosis. High levels of nitric oxide (NO) produced by inducible NO synthase (iNOS) have been associated with atherosclerotic processes. Simvastatin is an HMG-CoA reductase inhibitor responsible for many clinical benefits. The aim of this study was to detect and quantify changes in endothelial expression of P-selectin, VCAM-1, ICAM-1 and iNOS in the vessel wall after the short-term administration of simvastatin in a rabbit model of atherosclerosis. Eighteen New Zealand White rabbits were randomly divided into three groups (n = 6). In the cholesterol group, rabbits consumed an atherogenic diet (0.4% cholesterol) for eight weeks. In the simvastatin group, rabbits consumed an atherogenic diet for six weeks and then consumed an atherogenic diet supplemented with simvastatin (10 mg kg−1) for two weeks. Biochemical analysis showed that administration of simvastatin led to an almost two-fold lowering of the total serum cholesterol, VLDL, LDL and HDL, but not triglycerides, compared with the cholesterol-fed rabbits only. Stereological analysis of the immuno-histochemical staining revealed that administration of simvastatin (10 mg kg−1 daily) in an atherogenic diet decreased the endothelial expression of P-selectin, ICAM-1 and iNOS in both aortic arch and carotid artery compared with the cholesterol fed-rabbits only. We conclude that simvastatin has beneficial effects on endothelial function by decreasing expression of P-selectin, ICAM-1 and iNOS in endothelial cells in the very early stages of atherogenesis.

High sodium intake increases vascular superoxide formation and promotes atherosclerosis in apolipoprotein E‐deficient mice

Hypertension is a major risk factor for atherosclerosis. We tested the hypothesis whether high salt intake aggravates endothelial dysfunction and promotes atherosclerosis in apolipoprotein E-deficient mice (ApoE(-)/(-) mice) and their littermate controls (C57Bl/6 mice). The role of increased oxidative stress was also examined. A high-salt diet (NaCl 7%) for 12 weeks increased blood pressure and induced cardiac hypertrophy and albuminuria more pronouncedly in ApoE(-)/(-) mice compared with C57Bl/6. Endothelium-dependent vascular relaxation in response to acetylcholine was almost maximally impaired in ApoE(-)/(-) mice during a normal sodium diet. A high-salt diet did not further impair NO-mediated vascular relaxation. A high-salt diet also markedly attenuated endothelium-dependent relaxation in C57Bl/6 mice. Preincubation with the superoxide scavenger Tiron normalized endothelial function almost completely in both mice strains indicating the central role of increased oxidative stress in the pathogenesis. Aortic superoxide production and the extent of atherosclerotic lesions were greater in ApoE(-)/(-) mice on a normal-salt diet compared with C57Bl/6. The high-salt diet increased vascular superoxide formation and promoted atherosclerosis in ApoE(-)/(-) mice. Changes in dietary salt intake did not influence serum lipids in either mouse strains. Our findings suggest a detrimental role for high salt intake in the development of atherosclerosis and underscore the importance of increased oxidative stress in the pathogenesis salt-induced vascular damage.

Lipoproteinveränderungen unter Lynestrenol und Danazol in der hormonellen Behandlung der Endometriose

The Lipoprotein profile of 24 patients with endometriosis was determined before, during and after the treatment with the two steroid hormones Lynestrenol (10 mg/day) and Danazol (600-800 mg/day). The total cholesterol triglycerides, beta-, prebeta-, and Alphalipo -protein bound to cholesterol were determined. Both hormones cause a marked lowering of the Alpha-Lp-cholesterin. In addition, the beta-LP-cholesterin was elevated and the beta-alpha-LP-ratio was elevated. In the dosage used by us, Lynestrenol showed less effect on the Lipoprotein profile. Danazol caused changed in the beta- and alpha-lipoprotein pattern of highly pathological atherogenic types. The total cholesterol was not influenced. Since women in the fertile age group will suffer a higher risk of arteriosclerosis from an elevation of the beta-LP-cholesterin, the treatment with Danazol calls for a sophisticated monitoring of the lipid metabolism and care in the indication for long term treatment with Danazol or with Lynestrenol.

Endothelial dysfunction precedes atherosclerotic lesions and platelet activation in high fat diet-induced prothrombotic state

INTRODUCTION

Earlier we have demonstrated a prothrombotic state in spontaneously atherogenic rodents kept on Western-style high fat diet. The aim of the present study was to investigate the cellular mechanism of such prothrombotic state.

MATERIALS AND METHODS

Two kinds of diets, Western-style high fat diet containing 20% fat (w/w) and 0.05% cholesterol (w/w) and low fat diet containing 7% fat without cholesterol based on AIN93G, were added to diet-sensitive apolipoprotein E and low-density lipoprotein receptor double deficient male mice for 12 or 18 weeks from 6 weeks of age. Atherosclerosis was assessed by morphometry of the aortic wall or lipid-stained lesions. Endothelial function was measured by flow-mediated vasodilation (FMV) of the femoral artery. Platelet reactivity was measured ex vivo by a shear-induced platelet aggregation test.

RESULTS AND CONCLUSIONS

12 weeks feeding of mice with high fat diet significantly impaired FMV, as compared with mice fed with low fat diet (P<0.05). In contrast, there was no significant difference in the lipid-stained areas and in the reactivity of platelets between the two groups. 18 weeks feeding with high fat diet significantly impaired FMV (P<0.05) and enhanced both lipid-stained areas (P<0.05) and platelet reactivity (P<0.01). These findings show that in high fat diet-induced prothrombotic state, endothelial dysfunction precedes both the morphologically detectable lesions and the enhancement of platelet reactivity.

Serum levels of soluble vascular cell adhesion molecule-1 are decreased in women receiving oral contraceptives compared with normally menstruating women: implications in atherosclerosis

OBJECTIVE

The primary objective was to assess whether short-term changes in estradiol (E2), such as those observed in the menstrual cycle, alter serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), and whether VCAM-1 expression is suppressed in long-term users of exogenous estrogens. The secondary objective was to assess the association, if any, between inflammatory cytokines and expression of sVCAM-1.

DESIGN

Prospective collection of serum samples in healthy volunteers.

SETTING

University hospital.

PATIENTS(S)

Thirty-one normally menstruating women and 37 oral contraceptive (OC) users. Interventions included serum collection in the early follicular, late follicular, and midluteal phases of the menstrual cycle and once in oral contraceptive users.

MAIN OUTCOME MEASURE(S)

Samples were assayed for sVCAM-1, tumor necrosis factor alpha (TNF-alpha), and interleukin (IL)-6 by enzyme-linked immunoabsorbent assay (ELISA). Estradiol (E2) was measured by radioimmunoassay (RIA).

RESULT(S)

Oral contraceptive users had significantly lower serum levels of sVCAM-1 compared with normally menstruating women. No significant change was noted in the mean values of sVCAM-1 throughout the menstrual cycle, despite the significant change in 17beta-estradiol levels. Throughout the menstrual cycle, a significant correlation was noted between the serum levels of TNF-alpha and sVCAM-1. The serum levels of IL-6 correlated with those of sVCAM-1 in the late follicular and midluteal phase of the cycle. Similar correlations were observed in OC users.

CONCLUSION(S)

Long-term exposure to exogenous estrogens suppresses serum levels of sVCAM-1. Short-term changes in endogenous estrogens, as observed during the menstrual cycle, may not alter VCAM-1 expression; TNF-alpha and IL-6 may play a role in the regulation of VCAM-1 expression in vivo.

C-reactive protein in atherosclerotic lesions: its origin and pathophysiological significance

C-reactive protein (CRP) is frequently deposited in the lesions of the arterial intima; however, the origin and pathological significance of CRP in these lesions are not completely understood. In this study, we measured CRP levels in the plasma of hypercholesterolemic rabbits and investigated CRP expression at both the mRNA and protein levels using rabbit and human atherosclerotic specimens. CRP levels were significantly elevated in both cholesterol-fed and Watanabe heritable hyperlipidemic rabbits, and CRP levels were clearly correlated with aortic atherosclerotic lesion size. Immunohistochemical staining coupled with Western blotting analysis revealed that CRP-immunoreactive proteins were found at all stages of atherosclerosis from the early to advanced lesions. CRP was present extracellularly and co-localized with apolipoprotein B but was rarely associated with the cytoplasm of macrophages and foam cells. Real-time reverse transcriptase-polymerase chain reaction analysis revealed that CRP mRNA in atherosclerotic lesions was barely detectable, and isolated macrophages did not express CRP mRNA, suggesting that CRP proteins found in the lesions were essentially derived from the circulation rather than synthesized de novo by vascular cells. These results suggest that there is a link between plasma CRP and the degree of atherosclerosis and that inhibition of plasma CRP may represent a therapeutic modality for the treatment of cardiovascular disease.

High cumulative insulin exposure: a risk factor of atherosclerosis in type 1 diabetes?

BACKGROUND

Since insulin therapy might have an atherogenic effect, we studied the relationship between cumulative insulin dose and atherosclerosis in type 1 diabetes. We have focused on patients with type 1 diabetes instead of type 2 diabetes to minimise the effect of insulin resistance as a potential confounder.

METHODS

An observational study was performed in 215 subjects with type 1 diabetes treated with multiple insulin injection therapy. Atherosclerosis was assessed by measurement of carotid intima-media thickness (CIMT).

RESULTS

The cumulative dose of regular insulin showed a positive and significant relation with CIMT: increase of 21 microm in CIMT per S.D. of insulin use (95% CI: 8-35 adjusted for gender and age), which remained unchanged after adjustment for duration of diabetes, HbA1c, BMI, pulse pressure, physical activity and carotid lumen diameter. A similar relation was found for intermediate-acting insulin: 15.5 microm per S.D. (2-29), which was no longer present after further adjustment.

CONCLUSIONS

These findings provide evidence that a high cumulative dose of regular insulin is a risk factor for atherosclerosis.

Modification of environmental toxicity by nutrients: implications in atherosclerosis

We hypothesize that nutrition can modulate the toxicity of environmental pollutants and thus modulate health and disease outcome associated with chemical insult. There is now increasing evidence that exposure to persistent organic pollutants, such as PCBs, can contribute to the development of inflammatory diseases such as atherosclerosis. Activation, chronic inflammation, and dysfunction of the vascular endothelium are critical events in the initiation and acceleration of atherosclerotic lesion formation. Our studies indicate that an increase in cellular oxidative stress and an imbalance in antioxidant status are critical events in PCB-mediated induction of inflammatory genes and endothelial cell dysfunction. Furthermore, we have found that specific dietary fats can further compromise endothelial dysfunction induced by selected PCBs and that antioxidant nutrients (such as vitamin E and dietary flavonoids) can protect against endothelial cell damage mediated by these persistent organic pollutants. Our recent data suggest that membrane lipid rafts such as caveolae may play a major role in the regulation of PCB-induced inflammatory signaling in endothelial cells. In addition, PCB- and lipid-induced inflammation can be down-regulated by ligands of anti-atherogenic peroxisome proliferator-activated receptors (PPARs). We hypothesize that PCBs contribute to an endothelial inflammatory response in part by down-regulating PPAR signaling. Our data so far support our hypothesis that antioxidant nutrients and related bioactive compounds common in fruits and vegetables protect against environmental toxic insult to the vascular endothelium by down-regulation of signaling pathways involved in inflammatory responses and atherosclerosis. Even though the concept that nutrition may modify or ameliorate the toxicity of environmental chemicals is provocative and warrants further study, the implications for human health could be significant. More research is needed to understand observed interactions of PCB toxicity with nutritional interventions.

Effect of methanol extract of Sorbus cortex in a rat model of L-NAME-induced atherosclerosis

Chronic inhibition of nitric oxide (NO) synthesis by administration of high dose of N(G)-nitro-L-arginine methylester (L-NAME) induces vascular inflammation and subsequent atherosclerosis. We aimed to investigate whether the methanol extract of Sorbus commixta cortex (MSC) is able to prevent inflammatory process in a rat model of L-NAME-induced atherosclerosis. Chronic treatment with low or high doses of MSC prevented the L-NAME-induced increase in monocyte chemoattractant protein-1 (MCP-1) and nuclear factor-kappaB (NF-kappaB) p65 expressions as well as adhesion molecules including intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), and E-selectin in aorta. In addition, increased endothelin-1 (ET-1) and angiotensin converting enzyme (ACE) expressions and decreased endothelial cell NO synthase (ecNOS) expression in aorta from L-NAME treated group was reversed by treatment with MSC. From the histological examination, aortic segment from the L-NAME-treated rats revealed a thickening of intima and media, which was ameliorated by treatment with MSC. In conclusion, our results indicate that MSC can prevent atherosclerosis by inhibiting vascular over-expressions of vasoactive materials, pro-inflammatory transcription factor, and adhesion molecules and by augmenting ecNOS in chronic L-NAME-treated rat model.

In vivo optical analysis of quantitative changes in collagen and elastin during arterial remodeling

Altered collagen and elastin content correlates closely with remodeling of the arterial wall after injury. Optical analytical approaches have been shown to detect qualitative changes in plaque composition, but the capacity for detection of quantitative changes in arterial collagen and elastin content in vivo is not known. We have assessed fluorescence spectroscopy for detection of quantitative changes in arterial composition in situ, in rabbit models of angioplasty and stent implant. Fluorescence emission intensity (FEI) recorded at sites remote from the primary implant site was correlated with immunohistochemical (IH) analysis and extracted elastin and collagen. FEI was significantly decreased (P<0.05) after treatment with anti-inflammatory agents, and plaque area decreased on comparison with saline-treated rabbits after stent implant or angioplasty (P<or=0.013). Excellent correlations for FEI with elastin and collagen I, III and IV content measured by IH (R2>or=0.961) analysis were detected by multiple regression (MR) analysis. Good correlations also were found for FEI with elastin and collagen measured by high-performance liquid chromatography; MR analysis provided highly predictive values for collagen and elastin (R2>or=0.994). Fluorescence spectroscopic analysis detects quantitative compositional changes in arterial connective tissue in vivo, demonstrating changes at sites remote from primary angioplasty and stent implant sites.

A possible mechanism for atherosclerosis induced by polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAHs), aryl hydrocarbon receptor (AHR) ligands, induce atherogenesis. Liver X receptor (LXR) alpha is known to be involved in the control of cholesterol homeostasis. Thus, the purpose of this study was to investigate the effects of 3-methlycholanthrene (MC), one of the PAHs, on LXRalpha-mediated signal transductions. We found that expression of mRNAs for ATP binding cassette A1, sterol regulatory element binding protein 1c (SREBP-1c), fatty acid synthase, and stearoyl-CoA desaturase was suppressed by treatment of HepG2 cells with MC. A luciferase reporter assay revealed that LXRalpha- and SREBP-1c-mediated transactivations were inhibited by MC via AHR. Based on these lines of evidence, we propose that down-regulation of the LXRalpha-regulated genes by PAHs is one of the causes responsible for atherosclerosis induced by PAHs.

Feeding apolipoprotein E-knockout mice with cholesterol and fat enriched diets may be a model of non-alcoholic steatohepatitis

The present study was aimed (1) to investigate the effect of cholesterol and fat enriched diets on the development of steatohepatitis in apolipoprotein E-knockout mice, and (2) to study the chronological relationships between the development of hepatic alterations, hypercholesterolemia and atherosclerotic lesions in this experimental model. The study consisted of two protocols. Protocol 1 was used in 90 mice subdivided in groups of 18. For 10 weeks, each group was given a diet with different fat and cholesterol contents. Protocol 2 was used in 42 mice, subdivided in four groups. Each group was given a diet enriched with cholesterol and palm oil and they were sacrificed at 8, 13, 18 and 24 weeks of age. Results were as following. (1) Mice given high fat/high cholesterol diets developed an impairment of liver histology consisting of fat accumulation, macrophage proliferation, and inflammation. (2) These effects were modulated by the type of fat: olive oil was mainly associated with macrovesicular steatosis and cholesterol plus palm oil with severe steatohepatitis. (3) There was a chronological and quantitative relationship between liver impairment and the formation of atheromatous lesions. We conclude that apolipoprotein E-knockout mice may be a useful model for investigating the mechanisms of diet-induced steatohepatitis.

Effect of crocin on experimental atherosclerosis in quails and its mechanisms

In the present study, we examined the prophylaxis effect of crocin on experimental atherosclerosis and its possible mechanisms. The atherosclerosis formation was induced by hyperlipidamic diet in quails. At the 9th week, serum lipid, MDA and NO were measured, and HE staining was used to investigate the histopathological changes of aorta. Bovine aortic endothelial cells (EC) were obtained from the thoracic aorta of newborn calves. After incubation of the cells with Ox-LDL (50 mg x L(-1)) for 24 h, the activities of LDH, NO in culture media and activity of NOS in endothelial cells were measured, flow cytometer was used to determine the rate of endothelial cells apoptosis. Peritoneal macrophages were obtained from thioglycolate-injected mice. Cholesterol and free cholesterol in cells were assayed after incubation of the cells with Ox-LDL. Bovine aortic smooth muscle cells (SMC) were obtained from the thoracic aorta of newborn calf. Proliferation was induced by 100 microg x L(-1) Ox-LDL and antiproliferative effect of crocin on SMCs were observed. SMCs cycle phases were measured by flow cytometry. SMCs were loaded with Fluo-3/AM and [Ca2+]i was measured by Laser Scanning Confocal Microscope (LSCM). Crocin could reduce the level of serum TC, TG, LDL-C and inhibit the formation of aortic plaque. Crocin could reduce MDA and inhibit the descending of NO in serum. Compared with control, Ox-LDL group could increase the activity of LDH and decrease activity of NO in culture media and activity of NOS in endothelial cells, preincubated with crocin, the effects of Ox-LDL were inhibited. Crocin could decrease the EC apoptosis induced by Ox-LDL. Crocin concentration-dependently inhibited the TC and CE elevation induced by Ox-LDL in macrophages. Crocin could inhibit the proliferation of SMCs induced by Ox-LDL. In the presence or absence of extracellular Ca2+, crocin concentration-dependently inhibited the [Ca2+]i elevation induced by 120 mg x L(-1)Ox-LDL, In the absence of extracellular Ca2+, crocin could inhibit the [Ca2+]i elevation induced by CHCl3 in a concentration-dependent manner. The results indicated that crocin could inhibit the formation of atherosclerosis in quails. Crocin had protective effects on endothelial cells. Crocin could decrease CE in macrophages and uptake of Ox-LDL, inhibiting the formation of foam cell, which would promote the initiation and progression of atherosclerosis. Crocin could inhibit the [Ca2+]i elevation in smooth muscle cell, Ca2+ is an important second messenger that regulates a variety of cellular processes, including smooth muscle cell proliferation and gene expression . Crocin exerted antiatherosclerotic effects through decreasing the level of Ox-LDL that plays an important role in the initiation and progression of atherosclerosis.

Cocaine-induced renal disease

Cocaine has anaesthetic, vasoconstrictive and CNS stimulatory effects. Presently, it is used clinically as a local anaesthetic and abused as a recreational drug. It has been implicated in both acute and chronic renal failure and has been reported to affect every aspect of the nephron. This article will review the spectrum of cocaine-induced kidney disease and attempt to give insight into the pathophysiological mechanisms involved.

Adverse effects of danazol prophylaxis on the lipid profiles of patients with hereditary angioedema

BACKGROUND

Hereditary angioedema (HAE) is a rare disorder caused by the deficiency of the C1-inhibitor gene (C1INH) . Patients experience recurrent bouts of edema, which can occur in almost any region of the body. As regards the treatment of the disease, danazol (an attenuated androgen) is used, among other agents, for long-term prophylaxis.

OBJECTIVE

The aim of this study was to investigate the possible adverse effects of danazol on serum lipid profile, as well as to ascertain whether danazol treatment is associated with an increased risk of atherosclerosis.

METHODS

Serum concentrations of total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), triglycerides, apolipoprotein A-I, apolipoprotein B-100, and lipoprotein(a) were compared between danazol-treated patients with HAE and 2 control groups (ie, patients who did not receive long-term danazol prophylaxis and untreated healthy subjects).

RESULTS

Serum concentrations of HDL ( P = .0002 and P < .0001) and apolipoprotein A-I ( P = .0015 and P < .0001) were significantly lower, whereas LDL ( P = .0129 and P = .0127) and apolipoprotein B-100 ( P = .0456 and P = .0013) were higher in the danazol-treated patients compared with the 2 control groups, respectively. No significant difference was found in total cholesterol, triglyceride, or lipoprotein(a) levels. Patients who received danazol had an 11.6 (95% CI, 2.7-49.7) times higher risk for abnormally low HDL levels and a 4.4 (95% CI, 1.2-16.0) times lower risk for high LDL concentrations.

CONCLUSIONS

Our findings indicate that the long-term use of danazol is associated with an increased risk for early atherosclerosis in patients with HAE. Consequently, monitoring of HDL and LDL levels at regular intervals is recommended during follow-up.

Enalapril attenuates angiotensin II-induced atherosclerosis and vascular inflammation

Angiotensin converting enzyme (ACE) inhibitors prevent a wide variety of key events underlying atherogenesis. Whether these actions depend solely on reduction of angiotensin II (Ang II) generation is still to be determined. This study was undertaken to determine whether enalapril, an ACE inhibitor, prevents atherosclerosis and vascular inflammation induced by Ang II in apolipoprotein E-deficient (apoE-KO) mice. Subcutaneous infusion of Ang II (1.44 mg/(kg day)) for 4 weeks increased blood pressure and accelerated atherosclerosis development in the carotid arteries. The expression of the endothelial adhesion molecules E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), as well as the chemokines monocyte chemotactic protein-1 (MCP-1) and macrophage-colony stimulating factor (M-CSF) was up-regulated in the aortas of Ang II-treated mice. Enalapril co-treatment (25 mg/(kg day), in drinking water) prevented the development of atherosclerosis without affecting blood pressure or circulating cholesterol. In addition to preventing the Ang II-induced over-expression of adhesion molecules and chemokines in the aorta, enalapril up-regulated the expression of peroxisome proliferator-activated receptors (PPARs)-alpha and -gamma, potential anti-inflammatory transcription factors. In the aortic arch, a lesion-prone site, the co-treatment with enalapril reduced the percentage of arterial wall occupied by macrophages and foam cells, medial sclerosis and elastin reduplication. Together, these data suggest an important role for Ang II-independent mechanisms in the antiatherogenic and anti-inflammatory effects of ACE inhibitors.

Cilostazol Reduces Atherosclerosis by Inhibition of Superoxide and Tumor Necrosis Factor-α Formation in Low-Density Lipoprotein Receptor-Null Mice Fed High Cholesterol

This study shows that 6-[4-(1-cyclohexyl-1H-tetrazol-5-yl) butoxy]-3,4-dihydro-2(1H)-quinolinone (cilostazol) suppresses the atherosclerotic lesion formation in the low-density lipoprotein receptor (Ldlr)-null mice. Ldlr-null mice fed a high cholesterol diet showed multiple plaque lesions in the proximal ascending aorta including aortic sinus, accompanied by increased macrophage accumulation with increased expression of vascular cell adhesion molecule-1 (VCAM-1) and monocyte chemoattractant protein-1 (MCP-1). Supplementation of cilostazol (0.2% w/w) in diet significantly decreased the plaque lesions with reduced macrophage accumulation and suppression of VCAM-1 and MCP-1 in situ. Increased superoxide and tumor necrosis factor-alpha (TNF-alpha) production were significantly lowered by cilostazol in situ as well as in cultured human umbilical vein endothelial cells (HUVECs). TNF-alpha-induced increased inhibitory kappaBalpha degradation in the cytoplasm and nuclear factor-kappaB (NF-kappaB) p65 activation in the nuclei of HUVECs were reversed by cilostazol (1 approximately 100 microM) as well as by (E)-3[(4-t-butylphenyl)sulfonyl]-2-propenenitrile (BAY 11-7085) (10 microM), suggesting that cilostazol strongly inhibits NF-kappaB activation and p65 translocation into the nuclei. Furthermore, in gel shift and DNA-binding assay, cilostazol inhibited NF-kappaB/DNA complex and nuclear DNA-binding activity of the NF-kappaB in the nuclear extracts of the RAW 264.7 cells. Taken together, it is suggested that the anti-atherogenic effect of cilostazol in cholesterol-fed Ldlr-null mice is ascribed to its property to suppress superoxide and TNF-alpha formation, and thereby reducing NF-kappaB activation/transcription, VCAM-1/MCP-1 expressions, and monocyte recruitments.

Turpentine-induced inflammation reduces the hepatic expression of the multiple drug resistance gene, the plasma cholesterol concentration and the development of atherosclerosis in apolipoprotein E deficient mice

We aimed to investigate the effect of turpentine-induced inflammation in an atherosclerosis-prone murine model. We have induced a chronic aseptic inflammation in apolipoprotein E-deficient mice, with or without a dietary supplement of aspirin (n = 10, each), by the injection of a mixture (1:1) of turpentine and olive oil in the hind limb twice weekly for a period of 12 weeks. Control animals were injected with olive oil alone (n = 10). The control mice did show any alteration neither in plasma nor at the site of injection. Turpentine-treated mice showed a significant increase in plasma TNF-alpha and SAA concentrations which indicated a systemic inflammatory response that was not substantially affected by aspirin. Also, turpentine injections significantly reduced the plasma cholesterol concentration, probably decreasing intestinal cholesterol re-absorption, and attenuated the size of atherosclerotic lesion. Both effects were minimally influenced by aspirin. The burden of atherosclerosis correlated with plasma lipid levels but not with plasma inflammatory markers. Finally, there was a concomitant decrease in the expression of the hepatic mdr1b gene that correlated with the decrease in plasma cholesterol concentration. Therefore, we conclude that mdr1 is an additional factor to consider in the complexity of alterations in cholesterol metabolism that occur in this model.

[Effects of Pingyangmycin albumin microspheres on sclerostenosis of the rabbit central auricular arteries]

PURPOSE

The aim of this study was to investigate the mechanism of Pingyangmycin-albumin microspheres (PYM-AMS) acted on the rabbit central auricular arteries.

METHODS

In the study of randomized block design, 24 Japanese white rabbits were divided into 4 groups, 6 rabbits in each group. The animals were put on the operation table after being anaesthetized by intramuscular injection of Xumianxin (0.2 ml/Kg) and the interior division was blocked to stop drug liquid get into the interior ear. After being sterilized with 75% alcohol, No.1(PYM hydrochloride injection+0.9% NaCl), No.2(PYM+soybean oil), No.3(PYM-AMS+soybean oil) liquids which contained PYM 5mg/ml were injected into the central auricular arteries of the animals about 30 seconds (0.26 ml/per ear), respectively. Then these vessels were examined histologically after 2,7, 14, 21 days respectively.

RESULTS

After injection, in PYM+0.9% NS control group (No.1 liquid), the ears and vessels had no significant changes. In PYM+soybean oil control group (No.2 liquid), at the 2nd day, the endothelial cells were mild swollen. At the 7th day, some endothelial cells were dropped off. At the 14th day, the central auricular arteries had mild change, but the blood flow was not blocked. At the 21st day, the wall of the central auricular artery had more layers, especially on the intima, but the lumen was still obvious. A few of endothelial cells were proliferative. In PYM-AMS group(No.3 liquid), the blood was not resumed at once, and there was some oil in the vessels. At the 1st day, the injection site was mild swollen, and small thrombosis was observed in small vessels. At the 7th-14th day, the central auricular arteries were narrowed, but the blood could be observed. At the 21st day, the vessels had sclerostenosis, and the blood flow was blocked, but no scar and necrosis were observed. Under light microscopy, at the 2nd day, the endothelial cells were mild swollen and small vessels were embolized by PYM-AMS. At the 7th day, the endothelial cells were mild swollen. At the 14th day, the endothelial cells were proliferative and the wall of the central auricular artery had more layers. The lumen of the central artery changed mildly, while the surface of PYM-AMS was absorbed. At the 21st day, the wall of the central auricular artery was proliferative obviously and the artery became sclerostenosed, while cell division was observed. The PYM-AMS was obviously absorbed and some artery was sclerostenosed, while the wall of small vein was proliferative, too. The proliferative intima was proved to be muscle cells with Masson stain and van Gieson's stain. There were many smooth muscle cells, fibroblasts, myofibroblasts in the original blood vascular lumen on the 21st day under electron microscopy.

CONCLUSION

Pingyangmycin nonspecifically made the endothelia and vessels injured, and induced proliferation of endothelial cells and smooth muscle cells, and gradually the vessels became sclerostenosed. PYM-AMS had both sustained-releasing effect and embolization effect. PYM-AMS may be a better drug for treatment of large venous malformations and arteriovenous malformations.

Augmentation of Pulse Wave Velocity Precedes Vascular Structural Changes of the Aorta in Rats Treated with N.OMEGA.-Nitro-L-Arginine Methyl Ester

We examined the relationship between structural changes of the aorta and pulse wave velocity (PWV), and the effects of antihypertensive treatments on PWV in N(omega)-nitro-L-arginine methyl ester (L-NAME)-treated rats. Twelve-week-old Wistar-Kyoto (WKY) rats were divided into the following groups, all of which received drug treatment in their drinking water: an untreated control group (n = 36), an L-NAME-treated group (0.7 mg/ml) (n = 32), an L-NAME and angiotensin converting enzyme (ACE) inhibitor (ACEI)-treated group (imidapril: 0.4 mg/ml) (n = 8), and an L-NAME and hydralazine-treated group (0.2 mg/ml) (n = 10). PWV was measured at the same blood pressure (BP) level as in the control group and the wall-to-lumen ratio of the thoracic aorta was evaluated in all groups. In the L-NAME group, PWV increased compared with the value in the control group, at the same time that BP was increasing. After the third day of treatment, PWV was higher in the L-NAME group than in the control group after adjusting BP to the control level, while the wall-to-lumen ratios were equal between the two groups. After the first week of treatment, not only the adjusted PWV, but also the wall-to-lumen ratios were greater in the L-NAME group than in the control group. With administration of antihypertensive agents, both PWV and the thickening of the aortic wall were reduced, but there was no significant difference between the ACEI and hydralazine-treated groups. In conclusion, in a rat model of nitric oxide (NO) synthesis inhibition, the increase in PWV preceded the vascular structural changes, while antihypertensive treatment reduced both changes. There was no significant difference between treatments with ACEI and hydralazine in this model.

Cellular mechanisms of insulin resistance, lipodystrophy and atherosclerosis induced by HIV protease inhibitors

Accumulating clinical evidence now links HIV protease inhibitors (HPIs) to the pathogenesis of insulin resistance, dyslipidaemia, lipodystrophy and atherosclerosis associated with highly active anti-retroviral therapy. Here we briefly describe the evidence for a distinct causative role for HPIs, and explore the cellular mechanisms proposed to underlie these side-effects. Acute inhibition of GLUT4-mediated glucose transport, and defective insulin signalling induced by chronic exposure to nelfinavir, are described as cellular mechanisms of insulin resistance. Interference with adipogenesis and adipocyte apoptosis and nelfinavir-induced activation of lipolysis are discussed as potential mechanisms of HPI-induced lipodystrophy. HPI-induced free radical production, apoptosis and increased glucose utilization in vascular smooth muscle cells are presented as possible novel mechanisms for atherosclerosis. Common pathways and cause-effect relationships between the various cellular mechanisms presented are then discussed, with emphasis on the role of insulin resistance, free radical production and enhanced lipolysis. Understanding the cellular mechanisms of HPI-induced side-effects will enhance the search for improved anti-retroviral therapy, and may also shed light on the pathogenesis of common forms of insulin resistance, dyslipidaemia and atherosclerosis.

Effect of glucocorticoids on the arteries in rheumatoid arthritis

OBJECTIVE

Glucocorticoids are suspected to cause atherosclerosis. Because of the possibility that their antiinflammatory effect may be antiatherogenic, this study investigated the effect of glucocorticoids on the arteries of patients with rheumatoid arthritis (RA).

METHODS

We assessed the arteries of 647 patients with RA. Central atherosclerosis was measured using high-resolution carotid ultrasound for the presence of plaque and for the extent of carotid artery intima-media thickness (CaIMT). Peripheral atherosclerosis was assessed using the systolic pressures of the dorsal pedal, posterior tibial, and brachial arteries to obtain the ankle-brachial index (ABI). Cumulative glucocorticoid dose was determined using pharmacy records, supplemented by self-report. Cardiovascular (CV) risk factors and RA clinical manifestations were ascertained using clinical and laboratory methods.

RESULTS

Among the RA patients studied, 427 (66%) had received glucocorticoids. Of those who had never received glucocorticoids, 100 (47%) of 215 had carotid plaque and 17 (8%) of 219 had > or =1 incompressible lower-limb artery (ABI >1.3). Among patients in the highest tertile of lifetime glucocorticoid exposure (>16.24 gm prednisone), the frequency of carotid plaque increased to 85 (62%) of 138 (P = 0.006) and that of lower-limb arterial incompressibility increased to 24 (17%) of 140 (P = 0.008), with differences remaining significant after adjustment for age at onset, disease duration, sex, CV risk factors, and RA clinical manifestations (tender, swollen, and deformed joint counts, subcutaneous nodules, rheumatoid factor seropositivity, and erythrocyte sedimentation rate). The CaIMT also displayed an increase with higher glucocorticoid exposure, but the differences did not reach significance. Lower-limb artery obstruction (ABI < or =0.9) was not associated with glucocorticoid exposure.

CONCLUSION

In this RA sample, glucocorticoid exposure was associated with carotid plaque and arterial incompressibility, independent of CV risk factors and RA clinical manifestations. This supports a role for glucocorticoids in the CV complications that occur in RA.

Arsenic exposure exacerbates atherosclerotic plaque formation and increases nitrotyrosine and leukotriene biosynthesis

A correlation between arsenic and cardiovascular disease (CVD) has been established through epidemiological studies, although the mechanisms are unknown. Using a mouse model that develops atherosclerotic lesions on a normal chow diet, we have confirmed a connection between long-term arsenic intake and CVD. Our results reveal a significant increase in the degree of atherosclerotic plaque stenosis within the innominate artery of ApoE-/-/LDLr-/- mice treated with 10 ppm sodium arsenite (133 microM) in drinking water for 18 weeks compared to controls. Immunohistochemistry shows nitrotyrosine formation, a marker of reactive nitrogen species generation, is significantly higher within the atherosclerotic plaque of arsenic-treated mice. In addition, there is a significant increase in the 5-lipoxygenase (5-LO) product, leukotriene E4 (LTE4), in the serum of arsenic-treated mice. This is supported by induction of the 5-LO protein and subsequent increases in LTE4 synthesis in bovine aortic endothelial cells. This increase in LTE4 is partially inhibited by inhibitors of nitric oxide synthase, suggesting a link between reactive nitrogen species and arsenic-induced inflammation. Furthermore, there is a significant increase in prostacyclin (PGI2) in the serum of arsenic-treated mice. We conclude that changes in specific inflammatory mediators such as LTE4 and PGI2 are related to arsenic-induced atherosclerosis. In addition, amplified synthesis of reactive species such as peroxynitrite results in increased protein nitration in response to arsenic exposure. This finding is consistent with the pathology seen in human atherosclerotic plaques.

Peroxisome proliferator-activated receptors and atherogenesis: regulators of gene expression in vascular cells

A large body of data gathered over the past couple of years has identified the peroxisome proliferator-activated receptors (PPAR) alpha, gamma, and beta/delta as transcription factors exerting modulatory actions in vascular cells. PPARs, which belong to the nuclear receptor family of ligand-activated transcription factors, were originally described as gene regulators of various metabolic pathways. Although the PPARalpha, gamma, and beta/delta subtypes are approximately 60% to 80% homologous in their ligand- and DNA-binding domains, significant differences in ligand and target gene specificities are observed. PPARalpha is activated by polyunsaturated fatty acids and oxidized derivatives and by lipid-modifying drugs of the fibrate family, including fenofibrate or gemfibrozil. PPARalpha controls expression of genes implicated in lipid metabolism. PPARgamma, in contrast, is a key regulator of glucose homeostasis and adipogenesis. Ligands of PPARgamma include naturally occurring FA derivatives, such as hydroxyoctadecadienoic acids (HODEs), prostaglandin derivatives such as 15-deoxyDelta12,14-prostaglandin J2, and glitazones, insulin-sensitizing drugs presently used to treat patients with type 2 diabetes. Ligands for PPARbeta/delta are polyunsaturated fatty acids, prostaglandins, and synthetic compounds, some of which are presently in clinical development. PPARbeta/delta stimulates fatty acid oxidation predominantly acting in muscle. All PPARs are expressed in vascular cells, where they exhibit antiinflammatory and antiatherogenic properties. In addition, studies in various animal models as well as clinical data suggest that PPARalpha and PPARgamma activators can modulate atherogenesis in vivo. At present, no data are available relating to possible effects of PPARbeta/delta agonists on atherogenesis. Given the widespread use of PPARalpha and PPARgamma agonists in patients at high risk for cardiovascular disease, the understanding of their function in the vasculature is not only of basic interest but also has important clinical implications. This review will focus on the role of PPARs in the vasculature and summarize the present understanding of their effects on atherogenesis and its cardiovascular complications.

HIV Protease Inhibitors-induced Atherosclerosis: Prevention by α-Tocopherol

Prolonged treatments with inhibitors of human immunodeficiency(HIV)-encoded protease (ARPI) have been reported to induce early atherosclerotic events. Our in vitro study indicates that alpha-tocopherol may prevent drug-induced premature atherosclerosis since it interferes with CD36 scavenger receptor over-expression induced by ritonavir in monocytes. The mechanism of CD36 upregulation by ritonavir involves inhibition of the ubiquitin-proteasome system and alpha-tocopherol is able to normalize proteasome activity. These findings suggest that ARPI combined with early alpha-tocopherol supplementation may decrease the drug-induced atherosclerotic risk.

Liver gene expression associated with diet and lesion development in atherosclerosis-prone mice: induction of components of alternative complement pathway

Diet-induced changes in serum lipoproteins are a major risk factor for the development of atherosclerosis, the leading cause of mortality in Westernized countries. Atherosclerosis is now appreciated to be a systemic inflammatory disease where increased synthesis of inducible proteins by the liver, such as C-reactive protein (CRP) and others, may play roles in accelerating the disease process. To systematically investigate the genetic response of the liver to diet-induced atherosclerosis, we applied high-density microarray technology in a mouse model of atherosclerosis (LDLR−/−mouse). LDLR−/−mice and congenic (LDLR+/+) controls were placed on low-fat (LF) or high-fat (HF) Western-style diets. The Western diet produced sustained elevations in total cholesterol (2.5-fold for LDLR+/+, 5.0-fold LDLR−/−) relative to the respective LF groups. Tissues were harvested after 12 wk when significant atherosclerotic lesion development was first detectable by en face histomorphometry of oil red O-stained aortas. Diet, rather than genotype, was most highly associated with development of atherosclerotic lesions. Liver mRNA expression profiles of triplicate animals from each group were determined by high-density oligonucleotide microarrays; and genes with transcript levels influenced by genotype and diet were identified by two-way ANOVA. Approximately one-third of the 102 genes identified to be altered by diet [Pr(F) < 0.0005] were involved in lipid metabolism. In addition, we identified components of the alternative complement pathway, including C3, properdin, and factor D, for which mRNA levels were independently confirmed by quantitative real-time RT-PCR analysis, and C3 protein was demonstrated in aortic lesions by immunostaining. These findings suggest that induction of the alternative complement pathway may be an additional mechanism by which a high-fat/Western diet accelerates atherosclerosis.

Orchidectomy, but not ovariectomy, regulates angiotensin II-induced vascular diseases in apolipoprotein E-deficient mice

In humans, the incidence and severity of abdominal aortic aneurysms (AAA) are greater in males than in females. Chronic infusion of angiotensin II (AngII) into apolipoprotein E-deficient (apoE(-/-)) mice promotes atherosclerosis and causes the formation of AAAs. Just as human males are more susceptible to developing AAAs, male mice are more susceptible to AngII-induced AAAs. We hypothesized that sex steroid hormones mediate gender differences in AngII-induced AAA through regulation of the renin-angiotensin system. To define the role of ovarian hormones, female apoE(-/-) mice were subjected to ovariectomy or sham operation and infused with AngII (1000 ng/kg x min) for 28 d. Ovariectomy had no effect on AngII-induced atherosclerosis, nor did it influence the incidence or severity of AAA. To define the role of testicular hormones, male apoE(-/-) mice were subjected to orchidectomy (orx) or sham operation and infused with AngII (1000 ng/kg x min) for 28 d. Orx resulted in a profound reduction in AAA incidence (85% vs. 18%, sham vs. orx; P = 0.003) to the level observed in females (25%). However, orx had no effect on AngII-induced reductions in plasma renin concentration or spleen AngII receptor density. In contrast, orx resulted in an increase in atherosclerosis (0.46 +/- 0.07 vs. 1.20 +/- 0.21 mm(2), sham vs. orx; P = 0.002). These results suggest that estrogen does not mediate gender differences in AngII-induced AAA. In contrast, androgens mediate a higher incidence of AngII- induced AAA, through mechanisms that do not appear to involve circulating renin or angiotensin receptor density.

Arsenic and atherosclerosis

Epidemiological studies have demonstrated a correlation between environmental or occupational arsenic exposure and a risk of vascular diseases related to atherosclerosis. Studies summarized in this review suggest that arsenic induces endothelial dysfunction, including inflammatory and coagulating activity as well as impairs nitric oxide (NO) balance. This may provide the pathophysiological basis for atherogenic potential of arsenic. Consistent with these data, arsenic accelerates atherosclerosis in apolipoprotein E (ApoE) deficient mice, a model of human atherosclerosis.

Enhancement of human ACAT1 gene expression to promote the macrophage-derived foam cell formation by dexamethasone

In macrophages, the accumulation of cholesteryl esters synthesized by the activated acyl-coenzyme A:cholesterol acyltransferase-1 (ACAT1) results in the foam cell formation, a hallmark of early atherosclerotic lesions. In this study, with the treatment of a glucocorticoid hormone dexamethasone (Dex), lipid staining results clearly showed the large accumulation of lipid droplets containing cholesteryl esters in THP-1-derived macrophages exposed to lower concentration of the oxidized low-density lipoprotein (ox-LDL). More notably, when treated together with specific anti-ACAT inhibitors, the abundant cholesteryl ester accumulation was markedly diminished in THP-1-derived macrophages, confirming that ACAT is the key enzyme responsible for intracellular cholesteryl ester synthesis. RT-PCR and Western blot results indicated that Dex caused up-regulation of human ACAT1 expression at both the mRNA and protein levels in THP-1 and THP-1-derived macrophages. The luciferase activity assay demonstrated that Dex could enhance the activity of human ACAT1 gene P1 promoter, a major factor leading to the ACAT1 activation, in a cell-specific manner. Further experimental evidences showed that a glucocorticoid response element (GRE) located within human ACAT1 gene P1 promoter to response to the elevation of human ACAT1 gene expression by Dex could be functionally bound with glucocorticoid receptor (GR) proteins. These data supported the hypothesis that the clinical treatment with Dex, which increased the incidence of atherosclerosis, may in part due to enhancing the ACAT1 expression to promote the accumulation of cholesteryl esters during the macrophage-derived foam cell formation, an early stage of atherosclerosis.

Increase in serum amyloid a evoked by dietary cholesterol is associated with increased atherosclerosis in mice

BACKGROUND

Elevated serum amyloid A (SAA) levels are associated with increased cardiovascular risk. SAA levels can be increased by dietary fat and cholesterol. Moreover, SAA can cause lipoproteins to bind extracellular vascular proteoglycans, a process that is critical in atherogenesis. Therefore, we hypothesized that diet-induced increases in SAA would increase atherosclerosis independent of their effect on plasma cholesterol levels.

METHODS AND RESULTS

Female LDL-receptor-null (LDLR-/-) mice were fed high-saturated fat diets (21%, wt/wt), with or without added cholesterol (0.15%, wt/wt), for 10 weeks. Compared with chow-fed controls, the high-fat diets increased plasma SAA levels. Addition of cholesterol further increased SAA levels 2-fold (P<0.05) without further increasing plasma cholesterol levels. Addition of dietary cholesterol also increased atherosclerosis (P<0.05). Four lines of evidence suggest that SAA actually might cause atherosclerosis: (1) SAA levels when mice were euthanized correlated with the extent of atherosclerosis (r=0.49; P<0.02); (2) SAA levels after 5 weeks of diet correlated with the extent of atherosclerosis at 10 weeks (r=0.66; P<0.01); (3) binding of HDL from these animals to proteoglycans in vitro was related to the HDL-SAA content (r=0.65; P<0.01); and (4) immunoreactive SAA was present in lesion areas enriched with both proteoglycans and apolipoprotein A-I, the major HDL apolipoprotein.

CONCLUSIONS

Addition of cholesterol to a high-fat diet increased plasma SAA levels and atherosclerosis independent of an adverse effect on plasma lipoproteins, consistent with the hypothesis that SAA may promote atherosclerosis directly by mediating retention of SAA-enriched HDL to vascular proteoglycans.

Early endothelial dysfunction in cholesterol-fed rabbits: a non-invasive in vivo ultrasound study

Background

Endothelial function in hypercholesterolemic rabbits is usually evaluated ex vivo on isolated aortic rings. In vivo evaluation requires invasive imaging procedures that cannot be repeated serially.

Aim

We evaluated a non-invasive ultrasound technique to assess early endothelial function in rabbits and compare data with ex vivo measurements.

Methods

Twenty-four rabbits (fed with a cholesterol diet (0.5%) for 2 to 8 weeks) were given progressive infusions of acetylcholine (0.05–0.5 μg/kg/min) and their endothelial function was assessed in vivo by transcutaneous vascular ultrasound of the abdominal aorta. Ex vivo endothelial function was evaluated on isolated aortic rings and compared to in vivo data.

Results

Significant endothelial dysfunction was demonstrated in hypercholesterolemic animals as early as 2 weeks after beginning the cholesterol diet (aortic cross-sectional area variation: -2.9% vs. +4% for controls, p < 0.05). Unexpectedly, response to acetylcholine at 8 weeks was more variable. Endothelial function improved in 5 rabbits while 2 rabbits regained a normal endothelial function. These data corroborated well with ex vivo results.

Conclusion

Endothelial function can be evaluated non-invasively in vivo by transcutaneous vascular ultrasound of the abdominal aorta in the rabbit and results correlate well with ex vivo data.

Phytosterol oxidation products are absorbed in the intestinal lymphatics in rats but do not accelerate atherosclerosis in apolipoprotein E-deficient mice

Phytosterol oxidation products (oxyphytosterols) are formed during the processing and storage of foods. However, it is unknown whether oxyphytosterols affect human health. To address these issues, we prepared beta-sitosterol and campesterol oxides, evaluated their lymphatic absorption in rats, and examined the effect of an oxyphytosterol diet on atherosclerosis in apolipoprotein (apo) E-deficient mice. The lymphatic absorption of cholesterol and 6 oxyphytosterols (7alpha-hydroxy, 7beta-hydroxy, beta-epoxy, alpha-epoxy, dihydroxy, and 7-keto) of beta-sitosterol or campesterol was assessed in thoracic duct-cannulated rats fed an AIN-93G-based diet containing 2.5 g of cholesterol, oxyphytosterols, or intact phytosterols per kg. Lymphatic recoveries (on a mass basis) of oxycampesterols (15.9 +/- 2.8%, n = 10) and oxysitosterols (9.12 +/- 1.77%, n = 10) were higher than for campesterol (5.47 +/- 1.02%, n = 12, P < 0.05) and beta-sitosterol (2.16 +/- 0.37%, n = 12, P < 0.05), but lower than for cholesterol (37.3 +/- 8.3%, n = 6, P < 0.05). Apo E-deficient mice were fed an AIN-93G-based diet containing 0.2 g oxyphytosterols or intact phytosterols per kg for 9 wk. Diet-derived oxyphytosterols accumulated in the serum, liver, and aorta. Furthermore, the oxyphytosterol diet increased oxycholesterol in the serum compared to the phytosterol diet. However, there was no significant difference between the 2 groups in the serum and aortic cholesterol concentration, the lesion area in the aortic root, or 8-iso-prostaglandin F2alpha concentration in the urine. These results indicate that exogenous oxyphytosterols are well-absorbed and accumulate in the body, but do not promote the development of atherosclerosis in apo E-deficient mice.

Statins Augment Collateral Growth in Response to Ischemia but They Do Not Promote Cancer and Atherosclerosis

3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, or statins, are widely prescribed to lower cholesterol. Recent reports suggest that statins may promote angiogenesis in ischemic tissues. It remains to be elucidated whether statins potentially enhance unfavorable angiogenesis associated with tumor and atherosclerosis. Here, we induced hind limb ischemia in wild-type mice by resecting the right femoral artery and subsequently inoculated cancer cells in the same animal. Cerivastatin enhanced blood flow recovery in the ischemic hind limb as determined by laser Doppler imaging, whereas tumor growth was significantly retarded. Cerivastatin did not affect capillary density in tumors. Cerivastatin, pitavastatin, and fluvastatin inhibited atherosclerotic lesion progression in apolipoprotein E-deficient mice, whereas they augmented blood flow recovery and capillary formation in ischemic hind limb. Low-dose statins were more effective than high-dose statins in both augmentation of collateral flow recovery and inhibition of atherosclerosis. These results suggest that statins may not promote the development of cancer and atherosclerosis at the doses that augment collateral flow growth in ischemic tissues.

The Epitaxial Growth of Cholesterol Crystals from Bile Solutions on Calcite Substrates

Epitaxial relationships between the surfaces of inorganic and bioorganic crystals can be an important factor in crystal nucleation and growth processes in a variety of biological environments. Crystalline cholesterol monohydrate (ChM), a constituent of both gallstone and atherosclerotic plaques, is often found in association with assorted mineral phases. Using in situ atomic force microscopy (AFM) and well-characterized model bile solutions, the nucleation and epitaxial growth of ChM on calcite (104) surfaces in real-time is demonstrated. The growth rates of individual cholesterol islands formed on calcite substrates were determined at physiological temperatures. Evidence of Ostwald's ripening was also observed under these experimental conditions. The energetics of various (104) calcite/(001) ChM interfaces were calculated to determine the most stable interfacial structure. These simulations suggest that the interface is fully hydrated and that cholesterol hydroxyl groups are preferentially positioned above carbonate ions in the calcite surface. This combination of experimental and theoretical work provides a clearer picture of how preexisting mineral seeds might provide a viable growth template that can reduce the energetic barrier to cholesterol nucleation under some physiological conditions.