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Background and Purpose: C-reactive protein (CRP) is an inflammatory marker known to be a risk factor for stroke. We examined the associations between CRP, carotid atherosclerosis, white matter lesions, and lacunes as manifestations of cerebral large- and small-vessel disease., Methods: In the community-based Austrian Stroke Prevention Study, CRP concentrations were measured by a highly sensitive assay in 700 participants at baseline. All underwent carotid duplex scanning, and a subset of 505 subjects underwent brain magnetic resonance imaging. Imaging was repeated after 3 and 6 years. We graded carotid atherosclerosis in both common and internal carotid arteries on a 5-point scale and calculated the sum of scores as an index of the severity of carotid atherosclerosis. The volume of white matter lesions and the number of lacunes were considered small vessel disease-related brain abnormalities., Results: After adjustment for vascular risk factors, the severity and progression of extracranial carotid atherosclerosis increased with increasing quintiles of CRP. Only study participants in the fourth and fifth quintile (>2.50 mg/L) had significantly more baseline atherosclerosis and greater progression when we used the first quintile (<0.80 mg/L) as a reference. No interactions were seen between CRP quintiles and vascular risk factors for carotid atherosclerosis. The associations between severity and progression of small vessel disease-related brain abnormalities and CRP were nonsignificant., Conclusions: We found evidence for differential effects of CRP in different beds of the arterial brain supply. CRP was a marker for active carotid atherosclerosis but not for small vessel disease-related brain lesions.

Lp(a) appears to be one of the most atherogenic lipoproteins. It consists of an low-density lipoprotein core in addition to a covalently bound glycoprotein, apo(a). Apo(a) exists in numerous polymorphic forms. The size of the polymorphism is mediated by the variable number of kringle-4 Type 2 repeats found in apo(a). Plasma Lp(a) levels are determined to more than 90% by genetic factors. Plasma Lp(a) levels in healthy individuals correlate significantly highly with apo(a) biosynthesis, and not with its catabolism. There are several hormones that are known to have a strong effect on Lp(a) metabolism. In certain diseases, such as kidney disease, the Lp(a) catabolism is impaired, leading to elevations that are up to a fivefold increase. Lp(a) levels rise with age but are otherwise only little influenced by diet and lifestyle. There is no safe and efficient way of treating individuals with elevated plasma Lp(a) concentrations. Most of the lipid-lowering drugs have either no significant influence on Lp(a) or exhibit a variable effect in patients with different forms of primary and secondary hyperlipoproteinemia.

Apo(a) is a very atherogenic plasma protein without apparent function, which is highly expressed in humans. The variation in plasma Lp(a) concentration among individuals is considerable. Approximately 10-15% of the white population exhibit plasma Lp(a) concentrations above the atherogenic cut-off value of approximately 30 mg/dl. Since there is currently no safe way of treating those patients with drugs, we have tested the possibility of interfering with apo(a) biosynthesis by adenovirus-mediated expression of antisense apo(a) mRNA comprising the 5' UTR, the signal sequence and the first three kringles of native apo(a). Transduction of rat hepatoma McA RH 7777 cells which stably expressed apo(a) with 18 kringle IV (KIV) domains with apo(a)-antisense adenovirus (AS-Ad) at multiplicity of infection (MOI) of 30 reduced apo(a) synthesis to 23% as compared with control cells. As apo(a) is not synthesized in laboratory animals, we induced biosynthesis of the N-terminal fragments of apo(a) in mice by adenovirus-mediated gene transfer. Cotransduction of these mice with AS-Ad, which expressed up to eight times higher amounts of apo(a) than stable transgenic apo(a) mice, led to an almost complete disappearance of apo(a) from plasma. We conclude that the proposed AS-construct is very efficient in interfering with apo(a) biosynthesis in vivo. The strategy of inducing the synthesis of a nonexpressed protein followed by knocking it out by AS technology may also be applicable to other systems.

Background and Purpose: Genetic polymorphism at the paraoxonase locus is associated with serum concentration and activity of paraoxonase and with increased risk for coronary heart disease. Two frequent polymorphisms present at the paraoxonase gene are the methionine (M allele) leucine (L allele) interchange at position 54 and the arginine (B allele) glutamine (A allele) interchange at position 191. This is the first study to determine the effect of these polymorphisms on carotid atherosclerosis., Methods: The paraoxonase genotypes at positions 54 and 191 of 316 randomly selected individuals aged 44 to 75 years were determined by polymerase chain reaction-based restriction enzyme digestion. Carotid atherosclerosis was assessed by color-coded Duplex scanning and was graded on a 5-point scale ranging from 0 (normal) to 5 (complete luminal obstruction)., Results: The LL, LM, and MM genotypes at position 54 were noted in 137 (43.4%), 132 (41.8%), and 47 (14.9%) subjects; the AA, AB, and BB genotypes at position 191 occurred in 172 (54.4%), 124 (39.2%), and 20 (6.3%) individuals. The LL genotype was significantly associated with the presence and severity of carotid disease (P=0.022), whereas the 191 polymorphism had no effect. Logistic regression analysis with age and sex forced into the model demonstrated plasma fibrinogen (odds ratio [OR], 1.005 per mg/dL), LDL cholesterol (OR, 1.01 per mg/dL), cardiac disease (OR, 1.75), and the paraoxonase LL genotype to be significant predictors of carotid atherosclerosis. The ORs for the associations with age and sex were 1.09 (P=0.0003) and 1.66 (P=0.052) per year., Conclusions: These data suggest that the paraoxonase LL genotype may represent a genetic risk factor for carotid atherosclerosis.

Polymorphisms at the beta-fibrinogen locus have been shown to be associated with plasma concentration of fibrinogen and coronary heart disease. The effect of the genetic heterogeneity of fibrinogen on carotid atherosclerosis has not been determined so far. We examined the influence of the C148 --> T polymorphism on carotid disease in a large cohort of middle-aged to elderly subjects without evidence of neuropsychiatric disease. This polymorphism is located close to the consensus sequence of the interleukin-6 element and may represent a functional sequence variant. The genotype of 399 randomly selected, neurologically asymptomatic individuals, aged 45 to 75 years, was determined by denaturing gradient gel electrophoresis. Carotid atherosclerosis was assessed by color-coded duplex scanning and was graded on a five-point scale ranging from 0 (=normal) to 5 (=complete luminal obstruction). The C/C, C/T, and T/T genotypes were noted in 226 (56.6%), 148 (37.1 %), and 25 (6.3%) individuals, respectively. The T/T genotype group demonstrated higher grades of carotid atherosclerosis than did the C/C and C/T genotypes (P=.003). Logistic regression analysis created a model of independent predictors of carotid atherosclerosis that included apolipoprotein B (odds ratio [OR], 1.17/10 mg/dL), age (OR, 2.46/10 years), lifetime tobacco consumption (OR, 1.03/1000 g), presence of the beta-fibrinogen promoter T/T genotype (OR, 6.17), plasma fibrinogen concentration (OR, 1.05/10 mg/dL), and cardiac disease (OR, 1.80). These data suggest that the beta-fibrinogen promoter T/T148 genotype represents a genetic risk factor for carotid atherosclerosis in the middle-aged to elderly.

The plasma concentration of different lipoproteins were measured in 102 control children, in 42 children with a parent suffering from coronary heart disease (CHD), and in 50 children with a parent with cerebrovascular disease (CVD). Significant differences between controls and children in the other two groups were found for apolipoprotein A I, apolipoprotein B, and high density lipoprotein-cholesterol. Children of parents with CHD differed from controls in total cholesterol and apolipoprotein A II concentrations. A highly significant difference furthermore was found in lipoprotein (a) concentrations from children of parents with CHD in comparison with controls, but not between children of parents with CVD and controls. The difference in lipoprotein (a) concentrations (children of parents with CHD compared with controls) were only noticed in children above the age of 10 years. This could be explained by the observed rise of lipoprotein (a) between age 2 and 13 years, which was much more pronounced in the group with parents who had CHD. Plasma glycosaminoglycan concentrations were also measured in the three groups. They were significantly higher in children of parents with CHD and CVD compared with controls; they also varied with age.

The causes of atherosclerosis are numerous, but disturbances in lipid and lipoprotein (LP) metabolism undoubtedly play a key role. Although there exist multiple forms of genetic and secondary hyperlipoproteinemias linked with premature vascular diseases there are only a few LP that need to be considered: low-density LP, beta-very-low-density LP, chylomicron remnants and LP(a). In addition, low HDL levels have been found to represent an independent risk factor. Prolonged residence times of these LP lead to chemical modification and interaction with platelets, smooth muscle cells, endothelial cells and macrophages. Atherogenesis is thus a concerted action. Knowledge of the metabolic pathways of most of these LP is necessary in order to be able to specifically influence hyperlipoproteinemia with dietary measures or, ultimately, with lipid-lowering drugs.

Apo B-containing lipoproteins from human plasma were studied for their ability to form complexes with glycosaminoglycans (GAG) and proteoglycans (PG) in the presence of Ca++ and Mg++ ions. We studied low density lipoproteins (LDL), Lp(a) as well as Lpa-, a particle generated from Lp(a) by removing the specific antigen (apo-a). The strongest reactivity with all apo B-containing lipoproteins was found with PG, followed by GAG isolated from human aorta, and by chondroitin-6-sulphate. Lp(a), on the other hand, formed complexes with the highest glycan:lipoprotein ratio using all three complexing agents. Treatment of Lp(a) with neuraminidase did not change the reactivity. The reactivity of Lpa-, on the other hand, was between that of Lp(a) and LDL. Lipoprotein glycan complexes were incubated with mouse peritoneal macrophages. This caused cholesterol ester accumulation and foam cell formation. The amount of cholesterol ester formed correlated highly significantly with the reactivity of a given lipoprotein with different glycans. Sera obtained from patients suffering from myocardial infarction (MI) were incubated with LDL and Lp(a) and the reisolated lipoproteins were also incubated with macrophages. Lipoproteins reisolated from MI plasma caused foam cell formation with MPM to a greater extent than reisolated material incubated with normal plasma. The highest cholesteryl ester accumulation was found when Lp(a) reisolated from MI plasma was incubated with MPM. These results may at least partly explain the higher atherogenicity of Lp(a) in comparison with LDL.

The whole lipoprotein spectrum of human plasma may be divided into atherosclerotic and anti-atherosclerotic lipoproteins. To the first class belong apolipoprotein (apo) B and some apoE-containing lipoproteins of the very-low-density (VLDL), intermediate-density (IDL) and low-density (LDL) lipoprotein fractions. Anti-atherosclerotic lipoproteins are apoA-containing high-density lipoproteins (HDL). Circulating plasma lipoproteins are catabolized mainly by specific cell surface receptors (R) which react with apoB and apoE (B/E-R), for apoE (E-R) or for apoA (HDL-R). Whereas the B/E-R and E-R are responsible for the cellular uptake of lipoproteins and their lipid load by various organs, HDL-R are thought to promote lipid (cholesterol) efflux. There is an additional class of lipoprotein receptors, the so called scavenger-R which are responsible for the removal of altered or degraded lipoproteins for the circulation. Under normal physiological conditions, the concerted action of these receptors warrants efficient lipoprotein turnover and direction into target organs. Derangements of this system, however, may lead to the deposition and accumulation of atherogenic lipids, notably free cholesterol (FC) and cholesteryl esters (CE) in arterial tissue causing atherosclerosis and cardiac death.