Influence of age and sex on levels of anti-oxidized LDL antibodies and anti-LDL immune complexes in the general population

Most studies of antibodies to oxidized LDL have been undertaken in patients with different diseases and cardiovascular risk factors. However, very few studies have researched the distribution and determining factors of antibodies to oxidized LDL in the general population. A total of 1,354 persons (817 females and 537 males) aged 5-65 years were included in this study. They were selected randomly from the population census of Málaga, in southern Spain. The females had lower levels of total cholesterol and triglycerides and higher levels of HDL-cholesterol and a very significant increase (P < 0.0001) in levels of anti-oxidized LDL [low density lipoprotein modified by malondialdehyde (MDA-LDL)] antibodies but no difference in levels of immune complexes consisting of LDL and IgG antibodies (anti-LDL immune complex). Younger persons (16-35 years) had higher levels of anti-oxidized LDL (MDA-LDL) antibodies than persons older than 35 years (P = 0.05). Levels of immune complexes were significantly higher (P = 0.05) in persons aged 5-15 years than in persons older than 40 years. A very weak association was found between levels of anti-oxidized LDL (MDA-LDL) antibodies and anti-LDL immune complexes. The higher prevalence of anti-oxidized LDL (MDA-LDL) antibodies in females and young persons is in agreement with studies that found an inverse association between atherosclerosis and the level of these antibodies.     

Effect of atorvastatin on plasma apoE metabolism in patients with combined hyperlipidemia

Atorvastatin, a synthetic HMG-CoA reductase inhibitor used for the treatment of hyperlipidemia and the prevention of coronary artery disease, significantly lowers plasma cholesterol and low-density lipoprotein cholesterol (LDL-C) levels. It also reduces total plasma triglyceride and apoE concentrations. In view of the direct involvement of apoE in the pathogenesis of atherosclerosis, we have investigated the effect of atorvastatin treatment (40 mg/day) on in vivo rates of plasma apoE production and catabolism in six patients with combined hyperlipidemia using a primed constant infusion of deuterated leucine. Atorvastatin treatment resulted in a significant decrease (i.e., 30-37%) in levels of total triglyceride, cholesterol, LDL-C, and apoB in all six patients. Total plasma apoE concentration was reduced from 7.4 +/- 0.9 to 4.3 +/- 0.2 mg/dl (-38 +/- 8%, P < 0.05), predominantly due to a decrease in VLDL apoE (3.4 +/- 0.8 vs. 1.7 +/- 0.2 mg/dl; -42 +/- 11%) and IDL/LDL apoE (1.9 +/- 0.3 vs. 0.8 +/- 0.1 mg/dl; -57 +/- 6%). Total plasma lipoprotein apoE transport (i.e., production) was significantly reduced from 4.67 +/- 0.39 to 3.04 +/- 0.51 mg/kg/day (-34 +/- 10%, P < 0.05) and VLDL apoE transport was reduced from 3.82 +/- 0.67 to 2.26 +/- 0.42 mg/kg/day (-36 +/- 10%, P = 0.057). Plasma and VLDL apoE residence times and HDL apoE kinetic parameters were not significantly affected by drug treatment. Percentage decreases in VLDL apoE concentration and VLDL apoE production were significantly correlated with drug-induced reductions in VLDL triglyceride concentration (r = 0.99, P < 0.001; r = 0.88, P < 0.05, respectively, n = 6). Our results demonstrate that atorvastatin causes a pronounced decrease in total plasma and VLDL apoE concentrations and a significant decrease in plasma and VLDL apoE rates of production in patients with combined hyperlipidemia.     

Role of circulating soluble CD40 as an apoptotic marker in liver disease

OBJECTIVES: To measure levels of soluble CD40, a laboratory marker of apoptosis in patients with liver disease, determine its origin, and correlate the findings with disease activity and histology. DESIGN: Laboratory research study with comparison group. SETTING: Liver Institute, Laboratory of HLA Typing and Histopathology Department, Rabin Medical Center, Israel. SUBJECTS: One hundred ten patients with liver disease and 20 healthy controls. METHODS: Serum samples were collected from all patients; in addition, paired hepatic and portal vein samples were collected from 23 patients, and bile samples from 5 patients. Soluble CD40 was measured with an enzyme-linked immunosorbent assay. Apoptotic cells in liver tissue were identified by morphological criteria and quantified with the TUNEL assay. RESULTS: Soluble CD40 concentration was significantly higher in patients with liver disease than controls (mean 112.9 +/- 197.2 pg/ml vs. 24.2 +/- 9.1 pg/ml, p = 0.0001), with highest levels in the chronic viral hepatitis group (mean 131.7 +/- 137.5 pg/ml, p = 0.0001). Levels of sCD40 were correlated with serum creatinine, alkaline phosphatase, alpha-feto protein, and the apoptotic index. In the 23 paired samples, CD40 level was higher in the hepatic vein (mean 74.9 +/- 114.5 pg/ml) than the portal vein (mean 51.6 +/- 67.9 pg/ml); it was highly detectable in bile (mean 115.6 +/- 119.6 pg/ml, p = 0.0123). Untreated patients with chronic viral hepatitis (B and C) had higher levels (mean 106.2 +/- 76.5 pg/ml) than treated patients (mean 59.3 +/- 68.6 pg/ml, p = 0.049). CONCLUSIONS: Levels of soluble CD40 increase in different types of liver disease. It probably derives from the liver and is secreted into the bile. Levels correlate with the apoptotic index and are affected by antiviral treatment. Soluble CD40 may serve as a serum marker of apoptosis in liver disease.     

Serum Concentration and Chemotactic Activity of E-selectin (CD62E) in Inflammatory Bowel Disease

E-selectin (CD62E) is an endothelial specific glycoprotein belonging to the selectin family of adhesion molecules. Because a high expression of this molecule at intestinal mucosal surfaces in inflammatory bowel disease (IBD) has been described earlier, the aim was to assess serum levels of E-selectin (sE-selectin) and to correlate it to disease activity, and further to evaluate its chemotactic properties at physiological concentrations. Levels of sEselectin were measured by a sandwich ELISA technique in 31 IBD patients together with 15 healthy volunteers. In ulcerative colitis the median value was 0.46 nM (0.16-0.75), in Crohn's disease 0.47 nM (0.22-1.24), and in healthy controls 0.34 nM (0.22-0.83). No statistically significant differences in sE-selectin were revealed between these groups (p > 0.05). The in vitro chemotactic capabilities of E-selectin (in the concentration range of 0.10-31.4 nM) were assessed using the leading front technique. A significantly increased migratory response was found at concentrations of 1.00 (p < 0.05) and 3.14 nM (p < 0.02). It is concluded that sE-selectin in contrast to sICAM-1 does not act as a sensitive indicator of local immune activation in IBD. However, E-selectin may be important for recruitment and accumulation of neutrophilic granulocytes and other phagocytes involved in the inflammatory process seen in IBD. Future investigations are encouraged in order to reveal its in vivo effects.     

Altered lipoprotein subclass distribution and PAF-AH activity in subjects with generalized aggressive periodontitis

In this study, we examined whether the documented increase of plasma triglycerides in patients with generalized aggressive periodontitis (GAgP) is associated with changes in lipoprotein subclass distribution and/or LDL-associated platelet-activating factor acetylhydrolase (PAF-AH) activity. Lipoprotein subclasses were analyzed in whole plasma samples using nuclear magnetic resonance methods. Compared with subjects without periodontitis (NP subjects; n = 12), GAgP subjects (n = 12) had higher plasma levels of large, medium, and small VLDL (35.0 +/- 6.7 vs. 63.1 +/- 9.6 nmol/l; P = 0.025), higher levels of intermediate density lipoprotein (24.8 +/- 11.6 vs. 87.2 +/- 16.6 nmol/l; P = 0.006), lower levels of large LDL (448.3 +/- 48.5 vs. 315.8 +/- 59.4 nmol/l; P = 0.098), and higher levels of small LDL (488.2 +/- 104.2 vs. 946.7 +/- 151.6 nmol/l; P = 0.021). The average size of LDL from NP and GAgP subjects was 21.4 +/- 0.2 and 20.6 +/- 0.3 nm, respectively (P = 0.031). Compared with NP subjects, GAgP subjects had a greater number of circulating LDL particles (961.3 +/- 105.3 vs. 1,349.0 +/- 133.2 nmol/l; P = 0.032). Differences in the plasma levels of large, medium, and small HDL were not statistically significant. NP and GAgP subjects had similar plasma levels of total LDL-associated PAF-AH activity; however, LDL of GAgP subjects contained less PAF-AH activity per microgram of LDL protein (1,458.0 +/- 171.0 and 865.2 +/- 134 pmol/min/microg; P = 0.014). These results indicate that, in general, GAgP subjects have a more atherogenic lipoprotein profile and lower LDL-associated PAF-AH activity than NP subjects. These differences may help explain the increased risk of GAgP subjects for cardiovascular disease.     

Soluble LDL-immune complexes in type 2 diabetes and vascular disease.

BACKGROUND AND AIMS: The oxidative modification of LDL has been shown to affect its clearance and to exert cytotoxic and immunogenic effects. The objective of our study was to analyse markers of LDL oxidation-soluble LDL containing immune complexes (LDL-ICs) in type 2 diabetes with micro- and macrovascular disease. PATIENTS AND METHODS: The study included 69 diabetic patients with coronary artery disease (DM + CAD), 78 non-diabetics with CAD, 47 controls, and 27 diabetics with nephropathy and 36 free from complications. OxLDL antibodies and advanced glycated end-products were measured by ELISA, and LDL-IC apo B content after PEG precipitation. RESULTS: Determination of a broad range of oxLDL antibody activity in all study groups showed no significant differences. In contrast, the content of apo B, a component of the antigen moiety of oxLDL-ICs, was higher in CAD and diabetes (+ CAD) than in LDL-ICs isolated from controls (p < 0.001). LDL-ICs did not differ between patients with CAD + DM and CAD patients free from diabetes. LDL-IC levels in diabetic patients with or without microangiopathy were significantly higher than in healthy volunteers (PEG-apo B 0.278 +/- 0.107 vs. 0.165 +/- 105 g/l, p < 0.002; PEG-IgG 151.7 +/- 76 vs. 115.4 +/- 62 g/l, p < 0.05). However, there was no significant difference in the level of circulating LDL-ICs between the subgroup of diabetic patients with nephropathy/retinopathy and patients free of microvascular disease (Ab-oxLDL 27.7 +/- 10.4 vs. 27.1 +/- 9.3 AU, NS; PEG-apo B 0.324 +/- 0.111 vs. 0.287 +/- 0.124 g/l, NS; PEG-IgG 1.68 +/- 0.68 vs. 1.42 +/- 0.80 g/l, NS). There was a statistically significant positive correlation between AGE content and LDL-ICs (r = 0.35, p < 0.009). A significant but inverse correlation was recorded between triglyceride concentration and level of LDL-ICs in DM + CAD (r = - 0.32, p < 0.016) and CAD patients (r = - 0.35, p < 0.002). A highly significant negative correlation between triglycerides and circulating LDL-ICs (r = - 0.54, p < 0.039) was observed in patients with early nephropathy, but not in those with physiological proteinuria. It is known that at a high triglyceride level in type 2 diabetes, the majority of LDL are small and dense, thus being more susceptible to oxidative modification. This could be a possible mechanism explaining why more LDL-ICs, with a level inversely correlating with triglyceride concentration, are generated in diabetes. CONCLUSION: The increased level of circulating LDL-ICs is a risk factor for the general population, including those with diabetes. Our results suggested the contribution of LDL-ICs to the development of atherosclerosis to probably be more significant than the direct contribution of oxLDLAb itself.     

Serum E-selectin and erythrocyte membrane Na+K+ ATPase levels in patients with rheumatoid arthritis

We conducted this study to assess serum soluble E-selectin (sE-selectin) levels and erythrocyte membrane Na(+)K(+) ATPase activity in patients with rheumatoid arthritis (RA) and correlate the levels with disease activity. Levels of sE-selectin were measured in the serum of 20 patients with RA and 20 control subjects by an enzyme-linked immunosorbant assay. Na(+)K(+) ATPase activity was determined by a colorimetric method in RA patients and healthy controls. There were no statistically significant differences between the two groups with respect to demographic data such as age and sex (p > 0.05). The serum levels of sE-selectin, ESR and C-reactive protein (CRP) in RA patients were significantly higher than in healthy controls (p < 0.001). Erythrocyte membrane Na(+)K(+) ATPase activity was significantly lower in the RA group than in the control group (p < 0.001). Correlation analysis revealed significant positive correlations between soluble E-selectin and ESR (r = 0.457; p < 0.05) and CRP (r = 0.682; p < 0.01) levels. There were statistically significant negative correlations between erythrocyte membrane Na(+)K(+) ATPase activity and ESR (r = -0.450; p < 0.05) and CRP (r = -0.446; p < 0.05) levels. Additionally, a significant negative correlations between sE-selectin and Na(+)K(+) ATPase activity was observed (r = -0.80; p < 0.001). These results show that decreases in erythrocyte membrane Na(+)K(+) ATPase activity and increases in sE-selectin are observed in RA, and that increased levels of sE-selectin may also reflect disease status or activity.     

Elevated white blood cell count, CRP and fibrinogen levels are not associated with increased anti-endothelial and anti-ox-LDL antibody, MCP-1, and RANTES levels in early onset occlusive carotid artery disease

BACKGROUND: Inflammatory processes have importance in atherosclerosis. We evaluated if subjects below 55 years of age with occlusive carotid artery disease have higher serum levels of antibodies against oxidized LDL and endothelial cells and the chemokines MCP-1 and RANTES than age matched subjects without atherosclerosis. METHODS AND RESULTS: Sixty patients with occlusive carotid artery disease (stenosis or occlusion) and 30 age-matched controls participated in the study. We measured the degree of carotid artery stenosis and intima-media thickness (IMT) by duplex ultrasound. White blood cell count (WBC), C-reactive protein (CRP), and fibrinogen levels were significantly higher in patients (means+/-SD: 7.5+/-1.8 vs. 6.1+/-1.1 G/L, p<0.001; 7.7+/-20.7 vs. 2.5+/-1.9 mg/L, p=0.015; and 3.7+/-0.9 vs. 3.1+/-0.5 g/L, p<0.001, respectively). Antibody levels against oxidized LDL and endothelial cells (21.1+/-22.9 and 19.9+/-15.3 EU/mL, p=0.6; and 19+/-15 vs. 20+/-9 U/mL, p=0.07) and RANTES and MCP-1 levels (72.4+/-32.3 vs. 73.8+/-27.3 ng/mL, p=0.7; and 468+/-1041 vs. 318+/-131 pg/mL, p=0.7) did not differ significantly between patients and controls and did not correlate with IMT. CONCLUSIONS: Higher levels of WBC, CRP, and fibrinogen suggest an ongoing inflammation in early-onset carotid atherosclerosis, but increased IMT is not associated by the elevation of serum levels of chemokines and antibodies evaluated in this study.     

Adhesion molecules on peripheral blood lymphocyte subpopulations in the elderly

Adhesion molecules, such as CD49d, CD50 and CD62L, have important roles in many adhesive interactions involving cells of the immune system. Since it has been shown that many immunological alterations are present in aged subjects, we studied, by means of triple colour whole blood immunostaining and multiparametric flow cytometry, the expression and intensity level (MFI) of these molecules on peripheral blood lymphocyte subpopulations from 23 healthy elderly subjects and 13 young controls. In the elderly a decrease in total peripheral blood lymphocytes bearing CD62L antigen was observed (39 +/- 13% vs 63 +/- 6% and 745 +/- 312/mm3 vs 1,393 +/- 407/mm3; p<0.001), whereas the numbers of lymphocytes expressing CD49d and CD50 antigens were comparable in aged and young subjects. In addition, CD50 and CD62L MFI values on total peripheral blood lymphocytes were higher in elderly than in young subjects (5.23 +/- 1.03 vs 4.18 +/- 0.44, p = 0.001 and 2.60 +/- 0.35 vs 2.21 +/- 0.40, p = 0.005 respectively) while the intensity expression of CD49d was unchanged. The percentages and absolute numbers of T and B lymphocytes expressing CD62L were decreased in elderly compared to young subjects (CD62L+CD3+: 43 +/- 15% vs 66 +/- 9% and 581 +/- 257/mm3 vs 1,028 +/- 418/mm3, p<0.001; CD62L+CD19+: 78 +/- 12% vs 90 +/- 4%, p < 0.005 and 103 +/- 64/mm3 vs 207 +/- 98, p < 0.001). A decrease in the proportion of CD62L bearing NK cells was also observed in the elderly (25 +/- 14% vs 46 +/- 24%, p<0.005), although their absolute number was unchanged. No significant differences were detected in the proportion of T, B and NK lymphocytes expressing CD49d and CD50 antigens and only the absolute numbers of B cells expressing these adhesion molecules were lower in elderly (CD49d+CD19+: 121 +/- 71/mm3 and CD50+CD19+: 107 +/- 73/mm3) compared to young donors (CD49d+CD19+: 248 +/- 112/mm3 and CD50+CD19+: 235 +/- 120/mm3, p < 0.001). Moreover, the intensity of adhesion molecule expression was differentially modulated in the elderly depending on the specific lymphocyte cell population considered. The densities of CD49d, CD50 and CD62L antigens on B and NK lymphocytes from the two age groups were not different; on the contrary, T lymphocytes from elderly donors exhibited increased CD49d (1.69 +/- 0.09 vs 1.62 +/- 0.07, p < 0.05), CD50 (4.98 +/- 1.16 vs 3.77 +/- 0.46, p < 0.001) and CD62L (2.26 +/- 0.38 vs 1.99 +/- 0.37, p < 0.05) MFI values compared to young donors.     

TNF-alpha and myocardial matrix metalloproteinases in heart failure: relationship to LV remodeling

The cytokine tumor necrosis factor (TNF)-alpha has been causally linked to left ventricular (LV) remodeling, but the molecular basis for this effect is unknown. Matrix metalloproteinases (MMPs) have been implicated in cardiac remodeling and can be regulated by TNF-alpha. This study tested the central hypothesis that administration of a TNF-alpha blocking protein would prevent the induction of MMPs and alter the course of myocardial remodeling in developing LV failure. Adult dogs were randomly assigned to the following groups: 1) chronic pacing (250 beats/min, 28 days, n = 12), 2) chronic pacing with concomitant administration of a TNF-alpha blocking protein (TNF block) using a soluble p75 TNF receptor fusion protein (TNFR:Fc; administered at 0.5 mg/kg twice a week subcutaneously, n = 7), and 3) normal controls (n = 10). LV end-diastolic volume increased from control with chronic pacing (83 +/- 12 vs. 118 +/- 10 ml, P < 0.05) and was reduced with TNF block (97 +/- 9 ml, P < 0.05). MMP zymographic levels (92 kDa, pixels) increased from control with chronic pacing (36,848 +/- 9,593 vs. 87,247 +/- 12,912, P < 0.05) and was normalized by TNF block. Myocardial MMP-9 and MMP-13 levels by immunoblot increased with chronic pacing relative to controls (130 +/- 10% and 118 +/- 6%, P < 0.05) and was normalized by TNF block. These results provide evidence to suggest that TNF-alpha contributes to the myocardial remodeling process in evolving heart failure through the local induction of specific MMPs.     

Platelet microparticles-derived miR-25-3p promotes the hepatocyte proliferation and cell autophagy via reducing B-cell translocation gene 2

Platelets are critical regulators of liver regeneration, but the mechanisms are still not fully understood. Platelets have been shown to contain a wide variety of microRNAs (miRNAs) and play an important role in many diseases. However, the mechanism that how the platelet microparticles (PMPs)-derived miRNA regulate the hepatocyte proliferation is not very clear. In this study, we have successfully isolated and identified PMPs. We also found that PMPs, which could be well integrated into the HHL-5 cells, could upregulate the level of miR-25-3p in HHL-5 cells. Meanwhile, we found that PMPs-derived miR-25-3p promoted HHL-5 cells proliferation by accelerating cells into the S phase, and enhanced the autophagy by increasing the LC3II expression and reducing the P62 expression. Then, we proved that the miR-25-3p could target the B-cell translocation gene 2 (BTG2) and downregulate the expression levels of the BTG2 gene in HHL-5 cells. In addition, the overexpression of BTG2 significantly inhibited the proliferation and autophagy abilities of HHL-5 cells, while cotransfected miR-25-3p mimics or PMPs could partially rescue HHL-5 cells proliferation and autophagy. Furthermore, we proved that PMPs accelerated hepatocyte proliferation by regulating autophagy pathways. Therefore, PMPs-derived miR-25-3p promoted HHL-5 cell proliferation and autophagy by targeting BTG2, which may be a new therapeutic method for liver regeneration.     

Lysophosphatidylcholine molecular species in low density lipoprotein of type 2 diabetes.

To reveal the importance of lysoposphatidylcholine (LPC) in patients with Type 2 diabetes (DM), LPC in low density lipoprotein (LDL) was determined by high performance liquid chromatography in 38 patients with Type 2 DM and 31 age and sex-matched non-diabetic controls. Stearoyl LPC (SLPC) and palmitoyl LPC (PLPC) were detected in LDL. The contents of both LPCs per gram protein in LDL were increased in diabetic patients compared with the non-diabetics (1.99+/-0.94mg SLPC and 3.02+/-1.81 mg PLPC vs 1.47+/-0.57 mg SLPC and 2.30+/-0.83 mg PLPC, mean +/- SD, p < 0.01 and p < 0.05, respectively). PLPC showed a weak correlation with the levels of fasting plasma glucose (FPG) and HbA1c (r=0.27 and r=0.33, p < 0.05 and p < 0.01, respectively). The diabetic patients with macroangiopathy showed higher levels of PLPC per gram protein compared to those without macroangiopathy (4.60+/-2.61 mg vs 2.53+/1.15 mg, respectively, p < 0.05). The LPC molecular species may participate in the atherogenicity of LDL in patients with Type 2 diabetes.     

Tamoxifen decreases progesterone and nuclear androgen receptors in the human prostate

Androgen (AR) and progesterone (PR) receptors were measured in resected prostate tissues of patients with benign prostatic hypertrophy. One group of patients received an anti-estrogen, tamoxifen (Tm 20 mg b.i.d.) for 10 days prior to prostate resection; a second group served as controls and were untreated. Plasma levels of Tm were 200-500 pmol/ml at the time of surgery. Statistically significant decreases (P less than 0.05) were found in cytosol PR (154 fmol/mg DNA +/- 33 SE in 14 Tm-patients vs 266 +/- 40 SE in 13 untreated patients) and in nuclear AR (103 fmol/mg DNA +/- 70 SE in 18 Tm-patients vs 257 +/- 62 SE in 17 controls). Cytosol AR was not significantly different in Tm-treated patients (257 fmol/mg DNA +/- 79 SE in 15 Tm-patients vs 346 +/- 130 SE in 17 controls, P greater than 0.6). Although receptor recycling is one of several possible explanations, these decreases in progesterone and nuclear androgen receptors in Tm-treated patients suggest that estrogen has a role in the biological regulation of steroid receptors in the human prostate.     

Circulating CD62E+ microparticles and cardiovascular outcomes

Background

Activated endothelial cells release plasma membrane submicron vesicles expressing CD62E (E-selectin) into blood, known as endothelial microparticles (EMPs). We studied whether the levels of endothelial microparticles expressing CD62E⁺, CD31⁺/Annexin-V⁺, or CD31⁺/CD42⁻ predict cardiovascular outcomes in patients with stroke history.

Methods/Principal Findings

Patients with stroke history at least 3 months prior to enrolment were recruited. Peripheral blood EMP levels were measured by flow cytometry. Major cardiovascular events and death were monitored for 36 months. Three hundred patients were enrolled, of which 298 completed the study according to protocol. Major cardiovascular events occurred in 29 patients (9.7%). Nine patients died, five from cardiovascular causes. Cumulative event-free survival rates were lower in patients with high levels of CD62E⁺ microparticles. Multivariate Cox regression analysis adjusted for cardiovascular risk factors, medications and stroke etiologic groups showed an association between a high CD62E⁺ microparticle level and a risk of major cardiovascular events and hospitalization. Levels of other kinds of EMPs expressing CD31⁺/Annexin-V⁺ or CD31⁺/CD42⁻ markers were not predictive of cardiovascular outcomes.

Conclusion

A high level of CD62E⁺ microparticles is associated with cardiovascular events in patients with stroke history, suggesting that the systemic endothelial activation increases the risk for cardiovascular morbidities.     

Benzo[a]pyrene enhances lipid peroxidation induced DNA damage in aorta of apolipoprotein E knockout mice

The genotoxic compound benzo[a]pyrene (B[a]P) enhances atherosclerotic plaque progression, possibly by inducing oxidative stress and subsequent lipid peroxidation (LPO). Since LPO plays a key role in atherosclerosis, stable LPO derived DNA modifications such as 1,N6-ethenodeoxy-adenosine (epsilondA) and 3,N4-ethenodeoxy-cytidine (epsilondC) may be useful biomarkers for in vivo oxidative stress. In this study, benzo[a]pyrene-diol-epoxide (BPDE)-DNA, epsilondA and epsilondC were determined by 32P-postlabelling in apolipoprotein E knockout (ApoE-KO) mice treated with 5mg/kg B[a]P by gavage. After 4 days, BPDE-DNA adduct levels were higher in aorta (10.8 +/- 1.4 adducts/10(8) nucleotides) than in lung (3.3 +/- 0.7, P < 0.05), which is a known target organ for B[a]P. Levels of epsilondA were higher in aorta of B[a]P-exposed animals than in unexposed controls (8.1 +/- 4.4 vs 3.4 +/- 2.1 adducts per 10(8) parent nucleotides, P < 0.05). On the other hand, epsilondC levels were not affected by B[a]P exposure. Serum low density lipoprotein (LDL) levels were lower in B[a]P-exposed mice than in controls (9.3 +/- 3.7 and 13.3 +/- 4.0mmol/l, respectively), whereas high density lipoprotein (HDL) levels were higher (1.4 +/- 1.6 and 0.4 +/- 0.3mmol/l, respectively). Consequently, a three-fold difference in the LDL/HDL ratio was observed (P = 0.001). epsilondA levels were positively related with plasma HDL concentrations (R = 0.68, P = 0.02), suggesting that the HDL mediated protection of the vessel wall against reactive lipid peroxides was reduced in B[a]P-exposed apoE-KO mice. Our observations show that direct as well as lipid peroxidation induced DNA damage is formed by B[a]P in aorta of apoE-KO mice, which may be involved in atherosclerotic plaque progression. This study further indicates that etheno-DNA adducts are useful biomarkers for in vivo oxidative stress in atherosclerosis.     

Circulating oxidized low density lipoprotein, autoantibodies against them and homocysteine serum levels in diagnosis and estimation of severity of coronary artery disease

The oxidative hypothesis of atherosclerosis proposes that oxidative modification of low density lipoprotein (LDL) plays a critical role in atherogenesis. The evaluation of LDL oxidation in vivo is therefore very important. However, data concerning the evaluation of the above biochemical marker is very limited in clinical practice. This study was conducted to test the hypothesis that plasma levels of ox-LDL reflect atherosclerosis and determine the clinical significance in the measurement of circulating ox-LDL and autoantibodies against them as well as their correlation with homocysteine and lipid parameters in the diagnosis and severity of coronary heart disease. A total of 273 individuals were examined: 41 suffering from unstable angina pectoris (UAP), 62 from stable angina pectoris (SAP) and 170 healthy control subjects. We used a sensitive method for detecting ox-LDL that is based on a direct sandwich technique (ELISA) in which two monoclonal antibodies are directed against separate antigenic determinants on the oxidized apolipoprotein-B molecule along with another enzyme immunoassay designed to determine human antibodies to oxidized LDL (anti-oxLDL) directly in serum. Total homocysteine (HCY) was evaluated by means of a fully automated fluorescence polarization immunoassay. Patients with UAP exhibited marked elevations in oxLDL levels as compared to patients with SAP (161.2 +/- 28.4 vs. 119.2 +/- 26.6, p < 0.001) and the control subjects (67 +/- 18.8, p < 0.001). The difference in oxLDL levels between patients with SAP and the control group was also statistically significant. Similarly, patients with UAP showed marked elevations in anti-oxLDL antibodies compared to both patients with SAP (602.2 +/- 62.2 vs. 510.8 +/- 50.3,p < 0.001) and control subjects (368 +/- 79.6, p < 0.001). The difference in anti-oxLDL levels between patients with SAP and the controls was also statistically significant. OxLDL levels were not correlated with age in any of the groups studied. Triglycerides, LDL-cholesterol and total cholesterol were elevated in patients with UAP as opposed to patients with SAP and the control subjects, while HDL levels were elevated in the control subjects when compared to patients with SAP and UAP. Homocysteine levels were elevated in patients suffering from UAP and SAP when compared to healthy subjects. Patients with UAP or SAP did not differ on homocysteine levels. Our findings demonstrate the presence of oxLDL in vivo, its strong association with coronary artery disease as well as with the severity of the clinical presentation.     

Partial recovery of the endothelial glycocalyx upon rosuvastatin therapy in patients with heterozygous familial hypercholesterolemia

The endothelial glycocalyx has been shown to serve as a protective barrier between the flowing blood and the vessel wall in experimental models. The aim of this study was to evaluate whether hypercholesterolemia is associated with glycocalyx perturbation in humans, and if so, whether statin treatment can restore this. We measured systemic glycocalyx volume (V(G)) in 13 patients with heterozygous familial hypercholesterolemia (FH) after cessation of lipid-lowering therapy for a minimum of 4 weeks and 8 weeks after initiating rosuvastatin therapy. Normocholesterolemic subjects were used as controls. V(G) was estimated by subtracting the intravascular distribution volume of a glycocalyx permeable tracer (dextran 40) from that of a glycocalyx impermeable tracer (labeled erythrocytes). V(G) in untreated FH patients [LDL 225 +/- 57 mg/dl (mean +/- SD)] was significantly reduced compared with controls (LDL 93 +/- 24 mg/dl) (V(G) 0.8 +/- 0.3 vs. 1.7 +/- 0.6, respectively, P < 0.001). After normalization of LDL levels (95 +/- 33 mg/dl) upon 8 weeks of statin treatment, V(G) recovered only partially (V(G) 1.1 +/- 0.4 L, P = 0.04). The endothelial glycocalyx is profoundly reduced in FH patients, which may contribute to increased atherogenic vulnerability. This perturbation is partially restored upon short-term statin therapy.     

Low-density lipoprotein catabolism in WHHL rabbits after partial ileal bypass surgery

The effect of partial ileal bypass surgery (PIB) on lipoprotein concentrations and compositions and on the catabolism of low-density lipoproteins (LDL) was studied in Watanabe heritable hyperlipidemic (WHHL) rabbits. After PIB, total serum cholesterol was 65% lower (6.22 +/- 1.58 vs. 17.24 +/- 3.22 mmol/l) and LDL cholesterol 81% lower (2.02 +/- 0.95 vs. 10.90 +/- 3.60 mmol/l) than in control WHHL rabbits; cholesteryl esters, expressed as percentage of mass, were 55% lower in the very-low and intermediate-density lipoprotein (VLDL + IDL) fractions, and 45% lower in LDL, whereas triacylglycerols were 89% higher in VLDL + IDL and 121% higher in LDL. The fractional catabolic rate (FCR) of LDL protein (apoLDL) from operated animals was 10% higher than that from controls in all animals (0.55 +/- 0.10 vs. 0.50 +/- 0.10 pools/day; P less than 0.01). The FCR of autologous apoLDL in PIB rabbits was 50% higher than that of autologous apoLDL in control rabbits (0.63 +/- 0.05 vs. 0.42 +/- 0.06 pools/day); this was not caused by induction of receptor-mediated clearance of LDL. The production rate of apoLDL after PIB in PIB rabbits was 50% lower compared to control apoLDL in controls (26.0 +/- 6.7 vs. 51.7 +/- 16.4 mg/kg per day). We conclude that PIB lowers LDL cholesterol in WHHL rabbits by a decreased production of LDL, by an increased non-specific clearance of LDL and by compositional changes, which lead to LDL particles containing less cholesterol.     

Phosphoinositide signalling system in platelets of schizophrenic patients and the effect of neuroleptic therapy.

Alterations in the phosphoinositide signalling system have been proposed as a possible biological marker of schizophrenia. We studied the levels of inositol 1,4,5-trisphosphate (IP3), cytosolic Ca2+ concentrations ([Ca2+]i), and the incorporation of [32P]-orthophosphate into inositol phospholipids and phosphatidic acid (PA) in blood platelets of neuroleptic-treated schizophrenics in comparison with controls. The [Ca2+]i was significantly higher in platelets of one month neuroleptic-treated patients (155+/-5.8 nM) in comparison with controls (95+/-5.4 nM). Neuroleptic therapy decreased the [Ca2+]i, but even after long-term therapy it remained significantly higher (114+/-5.7 nM) than in controls. Differences were also found in the level of IP3 between controls (30+/-4.0 pmol/10(9) platelets), drug-free schizophrenics (52+/-9.0 pmol/10(9) platelets) and treated patients (50+/-6.0 pmol/10(9) platelets). The increased turnover of PA was observed in platelets of neuroleptic-treated schizophrenic patients. The study suggests that the regulation of calcium homeostasis and pathways involved in the phosphoinositide signalling system are altered in the platelets of schizophrenics. Neuroleptic therapy did not remove the observed changes in [Ca2+]i and IP3 levels.     

Persistent abnormalities in lipoprotein composition and cholesteryl ester transfer following lovastatin treatment

Optimally effective lipid-lowering agents should not only restore plasma lipids to normal levels but also correct potentially atherogenic alterations in lipoprotein composition and function often present in hyperlipidemic patients. Lovastatin, a competitive inhibitor of cholesterol biosynthesis, clearly lowers plasma cholesterol levels. Its effects on lipoprotein composition and cholesteryl ester transfer (CET), a key step in reverse cholesterol transport, however, are not known. Since abnormalities in CET and lipoprotein composition are present in patients with hypercholesterolemia, we studied these parameters of plasma lipoprotein transport in twelve hypercholesterolemic (HC; Type IIa) subjects (six male, six female) before and 2 months after lovastatin treatment (20 mg qd). Before lovastatin, the free cholesterol (FC)/lecithin (L) ratio in plasma, a new index of cardiovascular risk that reflects lipoprotein surface composition, was abnormally increased (1.18 +/- 0.26 vs controls 0.83 +/- 0.14; P less than 0.001) in very low density lipoproteins (VLDL) and high density lipoprotein-3 (HDL3), and remained so after treatment despite significant declines in whole plasma cholesterol (311.7 +/- 68.2 vs 215.6 +/- 27.2 mg/dl; P less than 0.001), low density lipoprotein (LDL)-cholesterol (206.3 +/- 47.9 vs 146.8 +/- 29.4; P less than 0.001), and apolipoprotein B (149 +/- 30 vs 110 +/- 17; P less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)