Effect of menopause on plaque morphologic characteristics in coronary atherosclerosis

BACKGROUND

Coronary artery disease in women appears 10 to 15 years later than in men. To test the hypothesis that the effects of estrogen may manifest themselves as histologic differences in coronary plaques, we examined the hearts of premenopausal and postmenopausal women who died suddenly from coronary artery disease.

METHODS

We studied 51 cases of sudden coronary death and 47 deaths in women who died from noncoronary causes. Coronary deaths were classified on the basis of histologic features. The number of acute plaque ruptures, healed plaque ruptures, vulnerable plaques, and acute plaque erosions were compared between groups. Postmortem values of serum total cholesterol, HDL cholesterol, and thiocyanate were measured, and menopausal status was confirmed by calculating body mass index.

RESULTS

Women older than 50 years of age were much more likely to have a ruptured plaque than were younger, premenopausal women. Plaque rupture was significantly associated with elevated total cholesterol level. In the 51 women who died of coronary disease, the mean number of vulnerable plaques increased significantly as women advanced into the postmenopausal years.

CONCLUSIONS

Our data suggest that estrogen has an anti-inflammatory effect on atherosclerotic plaques, resulting in plaque stabilization. Plaque erosion, the major substrate for thrombosis in premenopausal women, does not appear to be inhibited by estrogen. Because plaque progression may result both from repeated rupture and repeated erosion, a better understanding of the effect of estrogen on atherosclerosis may yield insights into the nature of coronary artery disease.

Review article: Antioxidant micronutrients and gastric cancer

A review of the literature reveals a very consistent association between gastric cancer risk and low intake of fruits and vegetables. This observation has been documented in many countries with different epidemiological techniques: interpopulation correlations, case-control studies and follow up of several cohorts. Low serum levels of beta-carotene and alpha-tocopherol, but not vitamin C, have been reported in patients with gastric dysplasia. Helicobacter pylori infection has been associated with lower concentrations of vitamin C in the gastric juice. Detailed studies in Colombia and New Orleans have shown a gradient towards lower concentration in the gastric juice and lower ratios of gastric juice to serum concentration of vitamin C in the following comparisons: i) lower vs. higher gastric cancer risk; ii) mild vs. advanced gastric precancerous histopathologic lesions; iii) mild vs. advanced degree of atrophy; iv) mild vs. advanced damage to the surface gastric epithelium; v) lower vs. higher gastric pH. Such a gradient is not observed for serum levels of vitamin C. The role of infection with H. pylori in the metabolism of ascorbic acid is discussed, as well as the possible role of ascorbic acid in inhibiting cell damage by reactive oxygen species.

Evidence for more extensive deposits of epitopes of oxidized low density lipoprotein in aortas of young people with elevated serum thiocyanate levels. PDAY Research Group

Elevated levels of low density lipoprotein (LDL) and smoking have long been recognized as risk factors for atherosclerosis and coronary heart disease (CHD). However, the mechanisms by which these factors contribute to the disease have not been fully elucidated. It has been postulated from in vitro studies using serum and LDL from smokers that smoking increases the oxidation of LDL, which in turn contributes to atherogenesis. We know of no direct evidence linking oxidized LDL (oxLDL) in human arteries to increased atherosclerosis in individuals who show elevated serum thiocyanate levels (HST) as an indicator of recent smoking. We have studied arterial samples from smokers micromorphometrically and found that 'smokers' have a greater area in which oxLDL can be identified in the early stages of the disease than do "nonsmokers', i.e., individuals with low serum thiocyanate levels (LST). This study demonstrates a positive correlation between the extent of oxLDL in the fatty streaks as well as the fatty plaques of standardized core sample areas of the thoracic and abdominal aortas of a sample group of young people, aged 15-34, who have evidence of recent smoking based on their postmortem serum thiocyanate levels.

Lipid overload and proteoglycan expression in chronic rejection of the human transplanted heart

The degree to which transplant arteriopathy in solid organ allografts is an atheromatous process remains somewhat controversial. If atheromata develop as common and integral components of the arteriopathic lesions, then the process may be approached therapeutically in a manner analogous to native atheromatous diseases. Approaches to understanding the arteriopathic process may include not only the modulation of alloimmunity, but also the interruption of "storage" phenomena. We have examined the epicardial coronary arteries of nearly 50 explanted human heart allografts using biochemical, morphological, morphometrical, immunohistochemical, and molecular techniques in an effort to establish the degree, nature, and distribution of lipid accumulation in the vessel walls. Concomitantly, we studied the ascertainment of proteoglycan gene expression, represented by biglycan and decorin messenger RNA, and the localization of proteoglycan proteins in the vessels. The degree of lipid and proteoglycan buildup in both the intima and media of transplanted vessels is striking, and correlated strongly with intimal thickening, cross-sectional area reduction of the lumen, cumulative cyclosporine dose, corticosteroid dose, and serum cholesterol levels. Notably, lipid accumulation is not related to implant duration, this being true in an unselected series of "failed" allografts ranging from 4 to 1610 days post-transplant. The profound lipid accumulation in coronary walls of many grafts begins very early post-transplant and appears to contribute substantially to intimal thickening. Whether dysregulation of proteoglycan production leads to entrapment of lipids and lipoproteins remains an important and testable hypothesis.