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To develop a system for overexpressing genes in the vascular wall, we created transgenic mice using the reporter gene luciferase and the murine preproendothelin-1 promoter. In vitro analysis suggested that the murine 5'-flanking region contained endothelial-specific elements in a 5.9-kb fragment. Five transgenic mice colonies established from independent founders all exhibited the highest level of luciferase activity in the aorta with up to 8,540 light units per microgram of protein. Immunohistochemistry with anti-luciferase antisera revealed high levels of expression in the endothelial cells of both large and small arteries and lower levels of expression in veins and capillaries. Significant expression was also seen in arterial smooth muscle cells and in select epithelial surfaces which is consistent with the known distribution of endothelin-1 in mammals. The further demonstrate the targeting capability of this system, we overexpressed the lipid-peroxidating enzyme, human 15-lipoxygenase, in the vessel wall of transgenic mice. As with luciferase, expression of active enzyme and immunohistochemical localization in vascular cells were documented in transgenic animals. Hence, this new system can be used to direct expression of molecules to the vascular wall for the purpose of examining the biological significance of either overexpression or inhibition of select proteins.

It is well accepted that high levels of low-density lipoprotein (LDL) cholesterol in the plasma are associated with increased risk of atherosclerosis. The cellular and molecular mechanisms linking the two however, have not been fully resolved. One of the processes involved in atherogensis that has been intensively studied in this regard is the oxidation of LDL. Oxidation may convert LDL into an atherogenic form, which incites an inflammatory and proliferative response characteristic of the atherosclerotic lesion. One of the potential mediators in this process is the lipid peroxidating enzyme 15-lipoxygenase, which has been shown to be induced in the atherosclerotic lesion and is capable of oxidizing LDL. In this article, we review the motivation for looking at mechanisms of LDL oxidation and the proposed involvement of 15-lipoxygenase in the pathogenesis of the disease., (Copyright © 1995. Published by Elsevier Inc.)

Seventy-seven hypercholesterolemic patients participated in a 26-week, multicenter, randomized, double-blind, placebo-controlled study that investigated the efficacy and safety of pravastatin therapy. All patients had primary moderate hypercholesterolemia (total cholesterol 200-300 mg/dl, at the end of a 6-week dietary run-in period) and two additional coronary risk factors. Pravastatin, 20-40 mg/day given at bedtime, reduced total cholesterol by 19-22%, LDL-cholesterol by 24-30%, triglycerides by 10-30% and increased HDL-cholesterol by 9-13%. The drug caused mild elevation in alanine aminotransferase and aspartate aminotransferase. Almost all these elevations were within normal limits and no patient was clinically symptomatic. No other significant differences were observed between the pravastatin and the placebo-treated groups with regard to other adverse effects and to patient compliance and withdrawal. It is concluded that pravastatin has a beneficial effect on the lipid profile and that the drug is safe and well tolerated.

Seventeen male Yeshiva students were randomly allocated to a crossover study with two 12-wk dietary periods of monounsaturated fatty acids (MUFAs) vs a carbohydrate (CHO)-rich diet while concentrations of saturated (SFAs) and polyunsaturated (PUFAs) fatty acids were kept similar. Total plasma cholesterol (TC) decreased significantly by approximately 7.7% and low-density-lipoprotein cholesterol (LDL-C) by 14.4% on the MUFA diet, whereas on the CHO diet no significant change in cholesterol concentrations occurred, in contrast to that predicted by the equations of Keys and Hegsted. Concentrations of high-density-lipoprotein cholesterol (HDL-C) did not change significantly on either diet. On the MUFA diet there was a significantly lower proneness to peroxidation of plasma and LDL lipids and less extensive metabolism of conditioned LDL by peritoneal macrophages. We conclude that dietary MUFAs lower TC and LDL-C concentrations, independently of other dietary fatty acids and in addition may reduce the susceptibility of LDL to oxidative stress.

The effect of fish oil ingestion (10 g MaxEPA/day) on the susceptibility of plasma lipoproteins to peroxidation was examined in 20 smokers (study A and B) and 22 nonsmokers (study C). The subjects were examined at the onset of each study (baseline values), divided into control and experimental groups and reexamined 4 weeks later. Smokers were examined 40 h after abstention from smoking (0 time) and 90 min after acute smoking (4-6 cigarettes). The parameters studied were TBARS, which provide an indication of peroxidative injury, and metabolism of conditioned LDL by macrophages as a biological indicator. These parameters were significantly higher (P less than 0.05-0.001) when the 90 min values of smokers were compared to time 0. After 4 weeks of fish oil ingestion, a significant rise above baseline values (33-50%) in plasma and LDL TBARS was found in smokers examined at time 0 and after acute smoking. Peroxidative modification of LDL isolated from smokers fed fish oil resulted in significantly higher TBARS (34-41%) and its metabolism by macrophages was higher (65-139%) compared to baseline values. In nonsmokers, the baseline values of the above parameters were lower than in smokers. Ingestion of fish oil resulted in a significant rise in TBARS in plasma (33%), LDL (137%), conditioned LDL (36-40%) and metabolism of conditioned LDL (70%) by macrophages. In 6 nonsmokers and 4 smokers, 400 mg of vitamin E/day were given with the fish oil. In the nonsmokers, vitamin E counteracted the effect of fish oil more effectively than in the smokers. In the light of the present results, indiscriminate recommendation of fish oil supplementation to the population at large should be cautioned.

The effect of acute smoking on plasma lipoproteins was studied in seventeen smokers. In study 1, 7 subjects were examined prior to and 2 weeks after supplementation with vitamin C. In study 2, the effect of acute smoking was first determined in 10 additional subjects and subsequently they were divided into 3 groups, 3 and 4 subjects were supplemented with vitamin C or E, respectively, for 4 weeks, and 3 remained untreated. Plasma and LDL TBARS were examined at time zero (i.e., 40-48 h after total abstention from smoking) and at 90 min after acute smoking (5-7 cigarettes). In all 17 subjects examined prior to vitamin supplementation, significantly higher TBARS values were found in plasma, native LDL and LDL conditioned with smooth muscle cells (SMC) when the 90 min values were compared to 0 time. The LDL isolated after 90 min and conditioned with SMC was metabolized more extensively by mouse peritoneal macrophages than its zero time counterpart. The differences between the 0 time and 90 min values were not seen after the subjects had been supplemented with vitamin C for 2 or 4 weeks or with vitamin E for 4 weeks. The present results indicate that acute smoking exerts an oxidative stress on plasma lipoproteins and that higher plasma levels of natural antioxidants, such as vitamins C and E have a protective role.

A clinical report of a 67-year-old woman who developed reversible acute renal failure due to focal glomerulonephritis with severe nephrotic syndrome is presented. The patient required four weeks' dialysis treatment but recovered completely. The role of temporary dialysis and diuretics on the clinical course and the reversibility of the process in old age is discussed.

The effect of cigarette smoking on peroxidation of plasma low density lipoprotein (LDL) was studied in 16 smokers aged 23-56 years; 12 nonsmokers of similar age served as controls. The smokers were asked to refrain from smoking 24-40 h prior to testing. Peroxidation was assessed by determination of thiobarbituric acid reactive substances (TBARS) in fresh plasma and LDL and by an increase in 125I-LDL metabolism by peritoneal macrophages. There was no difference in TBARS in freshly prepared plasma or LDL of smokers and nonsmokers. However, LDL of smokers, conditioned by incubation with bovine aortic smooth muscle cells (SMC), had 2-fold or higher TBARS values when compared to SMC conditioned LDL of nonsmokers. 2-4-fold higher TBARS values were seen also in SMC conditioned LDL when the comparison was made between LDL isolated from plasma before smoking of 6-7 cigarettes (time 0), and LDL of the same individual isolated from plasma 90 min thereafter. The metabolism of SMC conditioned 125I-LDL by peritoneal macrophages was examined; LDL isolated from plasma of smokers at time 0 was metabolized twice as avidly as LDL of nonsmokers and a further increase was seen with LDL isolated 90 min after acute smoking. The present results indicate that cigarette smoking renders plasma LDL more susceptible to subsequent peroxidative modification by cellular elements.