Annette Andreasen

Small dense LDL particles--a predictor of coronary artery disease evaluated by invasive and CT-based techniques: a case-control study.

BackgroundCoronary angiography is the current standard method to evaluate coronary atherosclerosis in patients with suspected angina pectoris, but non-invasive CT scanning of the coronaries are increasingly used for the same purpose.Low-density lipoprotein (LDL) cholesterol and other lipid and lipoprotein variables are major risk factors for coronary artery disease. Small dense LDL particles may be of particular importance, but clinical studies evaluating their predictive value for coronary atherosclerosis are few.MethodsWe performed a study of 194 consecutive patients with chest pain, a priori considered of low to intermediate risk for significant coronary stenosis (>50% lumen obstruction) who were referred for elective coronary angiography. Plasma lipids and lipoproteins were measured including the subtype pattern of LDL particles, and all patients were examined by coronary CT scanning before coronary angiography.ResultsThe proportion of small dense LDL was a strong univariate predictor of significant coronary artery stenosis evaluated by both methods. After adjustment for age, gender, smoking, and waist circumference only results obtained by traditional coronary angiography remained statistically significant.ConclusionSmall dense LDL particles may add to risk stratification of patients with suspected angina pectoris.

Adipose tissue arachidonic acid content is associated with the expression of 5-lipoxygenase in atherosclerotic plaques

BackgroundThe content of arachidonic acid in adipose tissue is positively associated with the risk of myocardial infarction, whereas the content of eicosapentaenoic acid in adipose tissue has been reported to be negatively associated with the risk of myocardial infarction. Both arachidonic acid and eicosapentaenoic acid are substrates for the synthesis of pro-inflammatory leukotrienes and leukotrienes derived from eicosapentaenoic acid are generally much less potent. In this study we hypothesized that a high content of arachidonic acid in adipose tissue would reflect a high formation of arachidonic acid derived leukotrienes and a high expression of 5-lipoxygenase in atherosclerotic plaques. Likewise, we hypothesized that a high content of eicosapentaenoic acid in adipose tissue would reflect a low formation of arachidonic acid derived leukotrienes and a low expression of 5-lipoxygenase in plaques.MethodsIn a cross sectional study we included 45 consecutive subjects undergoing femoral thrombendarterectomy. The expression of 5-lipoxygenase in plaques was assessed by a semi-automated image analysis computer programme after immunohistochemical staining with mono-clonal 5-lipoxygenase antibodies. Leukotriene B4 and cysteinyl leukotriene formation from stimulated femoral artery plaques was quantified using ELISA methods. The fatty acid content of adipose tissue biopsies from the thigh was analyzed using gas chromatography. Associations between variables were assessed by Pearson correlations and were further explored in a multivariable linear regression model adjusting for potential confounders.ResultsA high content of arachidonic acid in adipose tissue was associated with a higher expression of 5-lipoxygenase in plaques (r = 0.32, p = 0.03), but no significant associations with leukotriene B4 (r = 0.22, p = 0.14) and cysteinyl leukotriene (r = −0.11, p = 0.46) formation was seen. No significant associations were found between the content of eicosapentaenoic acid in adipose tissue and 5-lipoxygenase expression or leukotriene formation in plaque.ConclusionsAdipose tissue arachidonic acid contents correlated positively with the expression of 5-lipoxygenase in plaques. This association might represent a causal link between adipose tissue arachidonic acid and the risk of myocardial infarction but confirmatory studies are needed.

Marine n-3 fatty acids are incorporated into atrial tissue but do not correlate with postoperative atrial fibrillation in cardiac surgery

OBJECTIVES Postoperative new-onset atrial fibrillation (POAF) in cardiac surgery is associated with increased morbidity and mortality. Because n-3 polyunsaturated fatty acids (n-3 PUFA) have an antiarrhythmic effect, we hypothesized that a high content of marine n-3 PUFA in the atrial wall was associated with a reduced risk of POAF. DESIGN Venous blood and tissue from the right atrial appendage were obtained from 50 patients undergoing elective cardiac surgery. We determined the content of marine n-3 PUFA in atrial tissue and in plasma phospholipids using gas chromatography. RESULTS The mean age of the patients (results available from 49 patients) was 66.0±10.4years, and 22, 14, 10 and 3 patients underwent coronary artery bypass surgery, valve, combined or other cardiac surgery, respectively. Eighteen patients (36.7%) developed POAF. Concentrations of n-3 PUFA in the atrial wall and in plasma phospholipids did not predict the development of POAF, but there were significant correlations between marine n-3 PUFA in atrial tissue and plasma. CONCLUSION Levels of marine n-3 PUFA in the atrial wall was not associated with the risk of POAF following cardiac surgery, despite significant correlations of marine n-3 PUFA in the atrium and in plasma phospholipids.