Tom Saldeen

Interactive Role of Infection, Inflammation and Traditional Risk Factors in Atherosclerosis and Coronary Artery Disease

Although first suggested at the turn of the 20th century, there is a renewed interest in the infectious theory of atherosclerosis. Studies done in many laboratories around the world over the past several years have shown an association between markers of inflammation and coronary atherosclerosis with an exacerbation of the inflammatory process during acute myocardial ischemia, particularly in the early stages of reperfusion. It is also being recognized that the traditional risk factors, such as smoking, dyslipidemia, hypertension and diabetes mellitus, do not explain the presence of coronary atherosclerosis in a large proportion of patients. We believe that in certain genetically susceptible people, infection with very common organisms, such as Chlamydia pneumoniae or cytomegalovirus, may lead to a localized infection and a chronic inflammatory reaction. Persistence of infection may relate to the degree of inflammation and severity of atherosclerosis. Early trials with appropriate antibiotic agents in some patients with a recent history of acute myocardial infarction have led to very salutary results. If patients with an infectious basis of atherosclerosis can be identified, a therapy directed at eradication of the offending organism may be appropriate.

Plasma tissue plasminogen activator inhibitor levels in coronary artery disease: Correlation with age and serum triglyceride concentrations

Increased levels of an endogenous inhibitor of tissue-plasminogen activator (t-PA) have been thought to relate to the genesis of acute myocardial ischemia. To examine the role of the rapid inhibitor of t-PA, plasma samples were analyzed from 75 patients with chest pain syndrome undergoing coronary angiography (mean age 57 years), 24 patients with clinically documented coronary artery disease (unstable angina, positive exercise stress test or previous history of myocardial infarction; mean age 58 years) and 15 young normal subjects (mean age 26 years). Plasma t-PA inhibitor levels were similar in age-matched patients regardless of the absence or presence (and degree) of coronary artery disease. Plasma t-PA inhibitor levels correlated significantly with age (r - 0.46, p less than 0.005), suggesting an age-dependent decrease in fibrinolytic activity. Plasma t-PA inhibitor levels also correlated significantly with serum triglyceride levels (r - 0.60, p less than 0.001), but not with coronary risk factors such as serum cholesterol, diabetes, hypertension, serum uric acid levels or body weight. Association of high levels of inhibitor of t-PA with hypertriglyceridemia may be of importance in the development of coronary thrombosis, especially in elderly patients. Nonetheless, this study does not suggest a pathogenic role of t-PA inhibitor in coronary atherosclerosis.

Preservation of Endogenous Antioxidant Activity and Inhibition of Lipid Peroxidation as Common Mechanisms of Antiatherosclerotic Effects of Vitamin E, Lovastatin and Amlodipine☆

OBJECTIVES We sought to document the common mechanisms of the antiatherogenic effects of the cholesterol-lowering hydroxy-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor lovastatin, the dihydropyridine Ca2+ blocker amlodipine and the antioxidant vitamin E. BACKGROUND Vitamin E, HMG-CoA reductase inhibitors and Ca2+ blockers each inhibit atherosclerosis in hypercholesterolemic animals. METHODS New Zealand White rabbits were fed regular chow (Group A), chow with 1% cholesterol (Group B), 1% cholesterol diet plus lovastatin (Group C), 1% cholesterol diet plus vitamin E (Group D) or 1% cholesterol diet plus amlodipine (Group E) for 12 weeks. The extent of aortic atherosclerosis was measured by planimetry of the sudanophilic area. Malondialdehyde (MDA) and superoxide dismutase (SOD) in blood were measured as indexes of lipid peroxidation and antioxidant activity, respectively. RESULTS Group A rabbits showed no atherosclerosis, whereas Group B rabbits had 17.4 +/- 9.3% (mean +/- SD) of the aorta covered with atherosclerosis, and Groups C, D and E rabbits had significantly less atherosclerosis. Plasma SOD activity was lower in Group B than in Group A (6.9 +/- 1.1 vs. 12.8 +/- 1.5 U/ml, p < 0.01) and was preserved in the groups given lovastatin, vitamin E or amlodipine with a high cholesterol diet. The serum MDA level was higher in Group B rabbits than Group A rabbits (12.1 +/- 2.6 vs. 1.2 +/- 0.1 nmol/ml, p < 0.01) and increased minimally in rabbits given lovastatin, vitamin E or amlodipine with a high cholesterol diet. In in vitro experiments, both lovastatin and amlodipine preserved SOD activity and reduced the oxidizability of low density lipoproteins by rabbit leukocytes. CONCLUSIONS This study suggests that a reduction in lipid peroxidation and preservation of SOD may be common mechanisms of antiatherosclerotic effects of lovastatin, vitamin E and amlodipine.

Differential effects of α- and γ-tocopherol on low-density lipoprotein oxidation, superoxide activity, platelet aggregation and arterial thrombogenesis

Abstract OBJECTIVES This study was designed to examine the differential effects of α- and γ-tocopherol on parameters of oxidation-antioxidation and thrombogenesis. BACKGROUND Experimental studies have shown that antioxidants, such as vitamin E (α-tocopherol), improve atherosclerotic plaque stability and vasomotor function, and decrease platelet aggregation and tendency to thrombus formation. METHODS Sprague Dawley rats were fed chow mixed with α- or γ-tocopherol (100 mg/kg/day) for 10 days. A filter soaked in 29% FeCl3was applied around the abdominal aorta to study the patterns of arterial thrombosis. The aortic blood flow was observed and continuously recorded using an ultrasonic Doppler flow probe. ADP-induced platelet aggregation, low-density lipoprotein oxidation induced by phorbol 12-myristate 13-acetate (PMA)-stimulated leukocytes, superoxide anion generation and superoxide dismutase (SOD) activity were also measured. RESULTS Both α- and γ-tocopherol decreased platelet aggregation and delayed time to occlusive thrombus (all p CONCLUSIONS This study indicates that both α- and γ-tocopherol decrease platelet aggregation and delay intraarterial thrombus formation, perhaps by an increase in endogenous antioxidant activity. γ-Tocopherol is significantly more potent than α-tocopherol in these effects.

Oxidized LDL Upregulates Angiotensin II Type 1 Receptor Expression in Cultured Human Coronary Artery Endothelial Cells The Potential Role of Transcription Factor NF-κB

BackgroundWe demonstrated earlier that angiotensin II (Ang II), by AT1 receptor activation, upregulates oxidized LDL (ox-LDL) endothelial receptor LOX-1 gene expression and uptake of ox-LDL in human coronary artery endothelial cells (HCAECs). In this study, we investigated the regulation of Ang II receptors (AT1R and AT2R) by ox-LDL and the role of the redox-sensitive transcription factor NF-&kgr;B in this process. Methods and ResultsHCAECs were incubated with ox-LDL for 24 hours. Ox-LDL (10 to 40 &mgr;g protein/mL) upregulated AT1R but not AT2R, mRNA, or protein. Ox-LDL degraded I&kgr;B&agr; in cytoplasm and activated transcription factor NF-&kgr;B (P65) in HCAEC nuclear extract. Treatment of cells with the antioxidant &agr;-tocopherol (10 to 50 &mgr;mol/L) attenuated ox-LDL–mediated degradation of I&kgr;B&agr; and activation of NF-&kgr;B (P65) and inhibited the upregulation of AT1R mRNA and protein. The role of NF-&kgr;B signal transduction was further examined by use of an NF-&kgr;B inhibitor, caffeic acid phenethyl ester (CAPE). Pretreatment of cells with CAPE inhibited ox-LDL–mediated degradation of I&kgr;B&agr; and NF-&kgr;B activation and inhibited ox-LDL–induced upregulation of AT1R expression. Incubation of cells with both ox-LDL and Ang II increased cell injury, measured as cell viability and LDH release, compared with either ox-LDL or Ang II alone. &agr;-Tocopherol as well as the specific AT1R blocker CV11974 (candesartan) attenuated the cell-injurious effects of ox-LDL. ConclusionsThese observations suggest an important role of ox-LDL–mediated AT1R upregulation in cell injury. In this process, NF-&kgr;B activation seems to play a critical role in signal transduction. These findings provide a basis for the use of antioxidants and AT1R blockers in designing therapy of atherosclerosis.

Mitochondrial DNA Sequencing of Shed Hairs and Saliva on Robbery Caps: Sensitivity and Matching Probabilities

Sequencing of mitochondrial DNA (mtDNA) has been used for human identification based on teeth and skeletal remains. Here, we describe an amplification system for the mtDNA control region (D-loop) suited for the analysis of shed hair, which constitutes the most common biological evidence material in forensic investigations. The success rate was over 90% when applied to evidence materials such as shed hair, saliva stains and saliva on stamps. The analysis of evidence materials collected from three similar robberies revealed the presence of mtDNA sequences identical to those of the suspects in the three crimes. The use of mtDNA control region sequences for individual identification was evaluated. The probability of identity by chance for the mtDNA types of the suspects in the robberies was found to vary between Pr = 0.017 - < 0.0017, depending on the reference population used, emphasizing the need for large population databases to obtain the appropriate estimate.

Arterial Hypotension and Hypoxaemia During Total Hip Replacement: The Importance of Thromboplastic Products, Fat Embolism and Acrylic Monomers

Thirteen patients submitted to total hip replacement surgery by the Charnley technique were studied. Operations were performed under epidural analgesia with the patients awake and breathing air. During the surgical procedure, the magnitude of tissue‐thromboplastic activity, the amount of fat globules, the presence of bone marrow cells and the concentrations of acrylic monomers were determined in the pulmonary arterial blood. Simultaneously, arterial blood gases and blood pressure were monitored.

The microembolism syndrome.

Abstract A combination of clinical, autopsy and experimental findings support the theory of the existence of a microembolism syndrome where the microemboli appear mainly in the lungs and give rise to a characteristic clinical, roentgenological and pathologico-anatomical pattern. This syndrome, which may be regarded as a microscopic analogue to the thromboembolism disease, is seen after severe traumata and intoxications, sepsis, peritonitis, pancreatitis, drowning, hypothermia and circulatory arrest. Intravascular coagulation occurring during a phase of inhibition of the fibrinolytic system results in increased permeability of the blood vessels with interstitial oedema, which is an important finding in the microembolism syndrome.

Inhibition of Arterial Thrombus Formation by ApoA1 Milano

The mutant form of human apoA1, known as apoA1 Milano, is formed as a result of arginine 173 to cysteine substitution and inhibits experimental atherosclerosis in cholesterol-fed animals. This study was designed to determine if apoA1 Milano would modify arterial thrombogenesis. Sprague Dawley rats were intravenously administered the carrier alone (n=8) or apoA1 Milano (20 mg. kg-1. d-1 for 4 to 10 days, n=17). The abdominal cavity was opened, and the abdominal aorta was isolated. Whatman paper impregnated with 35% FeCl3 was wrapped around the surface of the aorta, and aortic flow was recorded continuously. In carrier-treated rats, an occlusive platelet-fibrin-rich thrombus was formed in 21.2+/-4.1 (mean+/-SD) minutes. Treatment of rats with apoA1 Milano markedly delayed time to thrombus formation (38.8+/-11.9 versus 21.2+/-4.1 minutes, P<0. 01), inhibited platelet aggregation (25+/-7% versus 50+/-11%, P<0. 01), and reduced weight of the thrombus (18.5+/-1.8 versus 23.7+/-2. 3 mg/cm, P<0.01). Total cholesterol and HDL levels remained similar in both groups of rats, but plasma apoA1 Milano levels were elevated in apoA1 Milano-treated rats. In in vitro studies, incubation of platelets with apoA1 Milano reduced ADP-induced platelet aggregation by about 50%, but apoA1 Milano had no direct effect on vasoreactivity. This study provides further evidence for critical role of platelets in thrombosis. Use of apoA1 Milano offers a novel approach to inhibit arterial thrombosis.

Age-dependent Modulation of Heparan Sulfate Structure and Function

Heparan sulfate interacts with growth factors, matrix components, effectors and modulators of enzymatic catalysis as well as with microbial proteins via sulfated oligosaccharide domains. Although a number of such domains have been characterized, little is known about the regulation of their formation in vivo. Here we show that the structure of human aorta heparan sulfate is gradually modulated during aging in a manner that gives rise to markedly enhanced binding to isoforms of platelet-derived growth factor A and B chains containing polybasic cell retention sequences. By contrast, the binding to fibroblast growth factor 2 is affected to a much lesser extent. The enhanced binding of aorta heparan sulfate to platelet-derived growth factor is suggested to be due to an age-dependent increase of GlcN 6-O-sulfation, resulting in increased abundance of the trisulfated l-iduronic acid (2-OSO3)-GlcNSO3(6-OSO3) disaccharide unit. Such units have been shown to hallmark the platelet-derived growth factor A chain-binding site in heparan sulfate.