Dehydroepiandrosterone alters phospholipid profiles in Zucker rat muscle tissue

Insulin-resistant muscle tissue contains low proportions of arachidonic acid (AA), and increased proportions of muscle AA correlate with improved insulin sensitivity. Dehydroepiandrosterone (DHEA) and AA, like the thiazolidinedione drugs that decrease insulin resistance (IR), are peroxisome proliferators. Long-chain fatty acids (FA) have been named the "one true" endogenous ligand for activating the peroxisome proliferator-activator receptor (PPAR), and DHEA has been named a "good candidate" as a naturally occurring indirect activator of PPAR. This study was conducted to determine DHEA's effects on lipid profiles of skeletal and cardiac muscle in lean and obese Zucker rats (ZR), a model of IR, type 2 diabetes mellitus, and obesity. We hypothesize that DHEA may alter long-chain FA profiles in muscle tissue of obese rats such that they more closely resemble that of the lean. In our experiments, we employed a DHEA and a pair-fed (PF) group (n = 6) for 12 lean and 12 obese ZR. For 30 d, the diet of the two DHEA groups was supplemented with 0.6% DHEA; PF groups were given the average daily calories consumed by their corresponding treatment group. Hearts and gastrocnemius muscles were assayed for phospholipid (PL), free FA, and triglyceride (TG) FA profiles. The proportion of PL AA was significantly greater in both muscle types of lean compared to obese rats. Hearts from both DHEA groups had greater PL proportions of AA and less oleic (18:1) acid than their PF controls. Likewise, 18:1 proportions were significantly lower in the gastrocnemius; however, AA proportions were not significantly different. Similar phenotypic profile differences were observed in the TG fraction of both muscle types. There were no DHEA-related TG FA profile alterations.

Can associations between free fatty acid levels and metabolic parameters determine insulin resistance development in obese Zucker rats?

Elevated levels of serum free fatty acids (FFA) may be the metabolic alteration in obesity that leads to insulin resistance (IR) and type 2 diabetes mellitus (DM). The obese Zucker rat (ZR) is a genetic model of juvenile-onset obesity and type 2 DM. Compared with its lean sibling, the obese ZR is hyperinsulinemic, hypertriglyceridemic, and, beginning at about 6 months, hyperglycemic. The obese ZR demonstrates also IR, hyperphagia, increased lipogenesis, adipocyte hypertrophy and hyperplasia, and increased serum FFA levels. This study was designed to determine if serum FFA levels in lean and obese ZRs correlate with metabolic parameters associated with altered energy metabolism and IR. We hypothesized that serum FFA levels correlate with such serum parameters such as insulin, glucose, triglyceride, and total cholesterol, as well as such tissue parameters as retroperitoneal, perirenal, and epididymal fat pad weights and liver total lipid content. Twenty lean and 20 obese ZR were age/weight matched. For 14 days each rat had ad libitum access to a single bowl diet that was 50% fat, 30% carbohydrate, and 20% protein. Body weights and caloric intakes were measured daily. After 14 days, all animals were fasted overnight and euthanized. Serum and tissue measurements were made and various parameters were correlated with FFA levels. Serum FFA levels were almost 2 times higher in the obese ZR (approximately 1 mmol/L) compared to the lean (approximately 0.6 mmol/L). Each variable measured was significantly (p < or = 0.05) greater in the obese ZR compared to the lean. There were significant correlations between serum FFA levels and certain variables when data from all ZR were plotted against serum and tissue parameters. However, within phenotypes, there were no significant correlations. Serum FFA levels predict serum and tissue parameters that accompany obesity and IR when comparing lean and obese rats. However, FFA do not predict such parameters within one phenotype.

Lipoproteins and atherosclerosis in children: an early marriage?

AIM

Describe the relationship between serum lipoproteins and the development of atherosclerosis in young subjects aged 15-34 years, and discuss the implications for prevention of coronary heart disease.

DATA SYNTHESIS

Data from gross and microscopic evaluation of aorta and coronary arterial specimens as part of the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Study demonstrates that by the age of 15 years, all subjects have atherosclerosis. Lipoprotein risk factors for coronary heart disease are associated with the extent and prevalence of gross aortic and coronary atherosclerosis and with the development of microscopic coronary plaques that have qualities consistent with clinically significant lesions. Association of lipoprotein risk factors with intermediate type atherosclerotic lesions becomes evident in subjects in their late teens, whereas associations with raised lesions become evident in subjects greater than 25 years of age, consistent with a transitional role of intermediate lesion in the formation of advanced plaques.

CONCLUSIONS

Atherosclerosis begins in childhood and a significant number of young people have advanced coronary artery plaques. Early atherosclerosis is accelerated by lipoprotein risk factors. Thus, long-range prevention of atherosclerosis should begin in childhood and should include measures to control hyperlipidemia.

Immunolocalization of apolipoproteins in aortic atherosclerosis in American youths and young adults: findings from the PDAY study

The immunohistochemical distribution of apolipoproteins in the abdominal aortas of 142 men, 15-34 years of age, collected in a cooperative multicenter study group (Pathobiological Determinants of Atherosclerosis in Youth) was examined in relationship to serum VLDL+LDL+HDL cholesterol levels. ApoB deposits were limited to the intima of specimens with intimal fibro cellular thickening or atherosclerotic lesions. Apo A-I, E and J were observed in both the intima and media of the aortas with intimal lesions. The pattern of apoJ distribution was similar to that of apoA-I and E. The distribution patterns of these apolipoproteins in these young adults were very similar to those in adults and old men seen in an earlier study. The extent of apolipoprotein distribution in the intima and media increased with age and the stage of atherosclerosis development, but was not correlated significantly with serum VLDL+LDL or HDL cholesterol levels. The infiltration of lipoprotein particles into the aortic wall seems to be more strongly associated with the progression of intimal lesions rather than with serum cholesterol levels.

Dehydroepiandrosterone alters Zucker rat soleus and cardiac muscle lipid profiles

High levels of serum free fatty acids (FFA) and lower proportions of polyunsaturated (PU) FAs, specifically arachidonic acid (AA), are common in obesity, insulin resistance (IR), and type 2 diabetes mellitus. Dehydrepiandrosterone (DHEA) decreases body fat content, dietary fat consumption, and insulin levels in obese Zucker rats (ZR), a genetic model of human youth onset obesity and type 2 diabetes. This study was conducted to investigate DHEA's effects on lean and obese ZR serum FFA levels and total lipid (TL) FA profiles in heart and soleus muscle. We postulated that DHEA alters serum FFA levels and tissue TL FA profiles of obese ZR so that they resemble the levels and profiles of lean ZR. If so, DHEA may directly or indirectly alter tissue lipids, FFA flux, and perhaps lower IR in obese ZR. Lean and obese male ZR were divided into six groups with 10 animals in each: obese ad libitum control, obese pair-fed, obese DHEA, lean ad libitum control, lean pair-fed, and lean DHEA. All animals had ad libitum access to a diet whose calories were 50% fat, 30% carbohydrate, and 20% protein. Only the diets of the DHEA treatment groups were supplemented with 0.6% DHEA. Pair-fed groups were given the average number of calories per day consumed by their corresponding DHEA group, and ad libitum groups had 24-h access to the DHEA-free diet. Serum FFA levels and heart and soleus TL FA profiles were measured. Serum FFA levels were higher in obese (approximately 1 mmol/L) compared to lean (approximately 0.6 mmol/L) ZR, regardless of group. In hearts, monounsaturated (MU) FA were greater and PU FA were proportionally lower in obese compared to the lean rats. In soleus, saturated and MU FA were greater and PU FA were proportionally lower in the obese compared to the lean rats. DHEA groups displayed significantly increased proportions of TL AA and decreased oleic acid in both muscle types. Mechanisms by which DHEA alters TL FA profiles are a reflection of changes occurring within specific lipid fractions such as FFA, phospholipid, and triglyceride. This study provides initial insights into DHEA's lipid altering effects.

Histopathological modifications of early atherosclerotic lesions by risk factors--findings in PDAY subjects

To investigate whether histopathological modifications on early atherosclerotic lesions differ according to risk factors, we compared the histological findings of arteries obtained from a multicenter study in the USA (Pathobiological Determinants of Atherosclerosis in Youth, PDAY) with the antemortem risk factors. The materials comprised aortas and left anterior descending (LAD) coronary arteries of 140 male subjects. Measurements of intimal thickness, classification of intimal lesions, and density of foam cells and intimal fibrosis at the determined sites of LAD and aorta were evaluated. In both arteries, intimal thickness of hypertensives was greater than the normotensives with no definite proliferation of foam cells. In aortas, hypercholesterolemia was associated with an increase in foam cells, but not with an increase in intimal thickness. HDL-C value correlated inversely with number of foam cells in both the arteries, and the degree of intimal thickness in LADs, where early appearance of advanced lesion such as preatheroma and atheroma, was also indicated in the low HDL-C group. Smokers had less number of foam cells in both the arteries and more intensive intimal fibrosis in LAD than non-smokers. Our study suggests that there are several ways to advanced atherosclerotic lesions by risk factors.

Helicobacter pylori-associated gastritis and the ascorbic acid concentration in gastric juice

Patients infected with Helicobacter pylori have abnormally low ascorbic acid concentration in gastric juice. Low vitamin C intake and Helicobacter pylori infection have been related to an increased risk of gastric carcinoma. This report examines the association between ascorbic acid and Helicobacter pylori in patients referred for upper gastrointestinal endoscopy. Elevated gastric pH and the damage to the gastric surface epithelium were inversely associated with the ascorbic acid concentration in gastric juice. We postulate that these two factors mediate the ascorbic acid-decreasing effect of Helicobacter pylori. Patients with nonpremalignant conditions (normal gastric histology, diffuse antral gastritis, or duodenal ulcer) had lower gastric pH, less damage to the gastric epithelium, and higher levels of ascorbic acid in gastric juice than patients with atrophic gastritis, intestinal metaplasia, or dysplasia.

Arterial calcification as a marker for atherosclerosis in three Arctic populations

Accumulation of calcification in the arterial wall in the course of the atherogenic process is considered to be a manifestation of advanced atherosclerosis. In this study of autopsy specimens from Alaska non-Natives, Alaska Natives, and Greenland Natives, comparisons were made of the prevalence and extent of arterial calcification with that of all raised (advanced) lesions in the thoracic aorta, abdominal aorta, right coronary artery, and left anterior descending coronary artery, to determine the degree to which calcified lesions track the development of advanced lesions. Calcification was determined quantitatively from radiograph images of the fixed specimens; advanced lesion data on these specimens were available from prior studies. Findings show that the prevalence and extent of calcified lesions closely follows the pattern of prevalence and extent of advanced lesions among the groups. We conclude that calcification is a good marker for comparisons of the prevalence and may also provide a good measure of the extent of atherosclerosis in these populations.

Effects of nonlipid risk factors on atherosclerosis in youth with a favorable lipoprotein profile

BACKGROUND

The strong association between coronary heart disease and dyslipoproteinemia has often overshadowed the effects of the nonlipid risk factors-smoking, hypertension, obesity, and diabetes and impaired glucose tolerance-and even led to questioning the importance of these risk factors in the presence of a favorable lipoprotein profile.

METHODS AND RESULTS

A cooperative multicenter study, the Pathobiological Determinants of Atherosclerosis in Youth (PDAY), examined the relation of the nonlipid risk factors to atherosclerosis in 629 men and 227 women 15 to 34 years of age who died of external causes and who had a favorable lipoprotein profile (non-HDL cholesterol <4.14 mmol/L [<160 mg/dL] and HDL cholesterol >/=0.91 mmol/L [>/=35 mg/dL]). In the abdominal aorta, smokers had more extensive fatty streaks and raised lesions than nonsmokers, and hypertensive blacks had more raised lesions than normotensive blacks. In the right coronary artery, hypertensive blacks had more raised lesions than normotensive blacks, obese men (body mass index >/=30 kg/m(2)) had more extensive fatty streaks and raised lesions than nonobese men, and individuals with impaired glucose intolerance had more extensive fatty streaks. Obese men had more severe lesions (American Heart Association grade 2 through 5) of the left anterior descending coronary artery.

CONCLUSIONS

These substantial effects of the nonlipid risk factors on the extent and severity of coronary and aortic atherosclerosis, even in the presence of a favorable lipoprotein profile, support the need to control all cardiovascular risk factors.

Healed plaque ruptures and sudden coronary death: evidence that subclinical rupture has a role in plaque progression

BACKGROUND

Subclinical episodes of plaque disruption followed by healing are considered a mechanism of increased plaque burden. Detailed pathological studies of healed ruptures, however, are lacking.

METHODS AND RESULTS

We identified acute and healed ruptures from 142 men who died of sudden coronary death and performed morphometric measurements of plaque burden, luminal stenosis, and smooth muscle cell phenotype. Healed ruptures were found in 61% of hearts and were associated with healed myocardial infarction, increased heart weight, dyslipidemia, and diabetes. Multiple healed rupture sites with layering were frequently found in segments with acute and healed rupture; the percent area luminal narrowing increased with increased numbers of healed sites of previous rupture. The underlying percent luminal narrowing for acute ruptures (mean 79+/-15%) exceeded that for healed ruptures (mean 66+/-14%, P:=0.0001), and the area within the internal elastic lamina was significantly less in healed ruptures than in acute ruptures, when segments were grouped by distance from the ostium. Healed ruptures favored the accumulation of immature smooth muscle cells at repair sites, with a cellular proliferation index of 0.40+/-0.09%, significantly higher than the index at the sites of rupture (P:=0.008).

CONCLUSIONS

These data provide evidence that silent plaque rupture is a form of wound healing that results in increased percent stenosis. Healed ruptures occur in arteries with less cross-sectional area luminal narrowing than acute ruptures and are a frequent finding in men who die suddenly with severe coronary atherosclerosis.

Chemoprevention of gastric dysplasia: randomized trial of antioxidant supplements and anti-helicobacter pylori therapy

BACKGROUND

Previous research has identified a high risk of gastric carcinoma as well as a high prevalence of cancer precursor lesions in rural populations living in the province of Nariño, Colombia, in the Andes Mountains.

METHODS

A randomized, controlled chemoprevention trial was conducted in subjects with confirmed histologic diagnoses of multifocal nonmetaplastic atrophy and/or intestinal metaplasia, two precancerous lesions. Individuals were assigned to receive anti-Helicobacter pylori triple therapy and/or dietary supplementation with ascorbic acid, beta-carotene, or their corresponding placebos. Gastric biopsy specimens taken at baseline were compared with those taken at 72 months. Relative risks of progression, no change, and regression from multifocal nonmetaplastic atrophy and intestinal metaplasia were analyzed with multivariate polytomous logistic regression models to estimate treatment effects. All statistical tests were two-sided.

RESULTS

All three basic interventions resulted in statistically significant increases in the rates of regression: Relative risks were 4.8 (95% confidence interval [CI] = 1.6-14.2) for anti-H. pylori treatment, 5. 1 (95% CI = 1.7-15.0) for beta-carotene treatment, and 5.0 (95% CI = 1.7-14.4) for ascorbic acid treatment in subjects with atrophy. Corresponding relative risks of regression in subjects with intestinal metaplasia were 3.1 (95% CI = 1.0-9.3), 3.4 (95% CI = 1.1-9.8), and 3.3 (95% CI = 1.1-9.5). Combinations of treatments did not statistically significantly increase the regression rates. Curing the H. pylori infection (which occurred in 74% of the treated subjects) produced a marked and statistically significant increase in the rate of regression of the precursor lesions (relative risks = 8.7 [95% CI = 2.7-28.2] for subjects with atrophy and 5.4 [95% CI = 1.7-17.6] for subjects with intestinal metaplasia).

CONCLUSIONS

In the very high-risk population studied, effective anti-H. pylori treatment and dietary supplementation with antioxidant micronutrients may interfere with the precancerous process, mostly by increasing the rate of regression of cancer precursor lesions, and may be an effective strategy to prevent gastric carcinoma.

Atherosclerosis and omega-3 fatty acids in the populations of a fishing village and a farming village in Japan

The effect of different dietary habits on atherosclerosis was investigated by examining the content of ordinary diets and relevant risk factors through a mass health survey on two village populations in Japan. In total, 261 inhabitants in the fishing village and 209 in the farming village were examined for body build, blood pressure, and blood chemistry. Information on smoking habits and food consumption was obtained using a semi-quantitative item-frequency questionnaire. Pulse wave velocity of the aorta, intima-media thickness of the carotid artery, and atherosclerotic plaques as obtained by ultrasonography were used as measures of atherosclerosis. All measures of atherosclerosis are lower in the fishing village than in the farming village in both men and women. There is a striking 5-8-fold difference in the number of atherosclerotic plaques (P < 0.0001) between the populations. The observed differences in atherosclerosis parallels differences in dietary habits and differences in the serum essential fatty acids. Evaluation of the omega-3 fatty acids over the combined populations reveals a negative association with the number of plaques in the common carotid while the omega-6 fatty acids shows a weak positive association with plaques.

Origin of atherosclerosis in childhood and adolescence

Atherosclerosis begins in childhood as deposits of cholesterol and its esters, referred to as fatty streaks, in the intima of large muscular arteries. In some persons and at certain arterial sites, more lipid accumulates and is covered by a fibromuscular cap to form a fibrous plaque. Further changes in fibrous plaques render them vulnerable to rupture, an event that precipitates occlusive thrombosis and clinically manifest disease (sudden cardiac death, myocardial infarction, stroke, or peripheral arterial disease). In adults, elevated non-HDL-cholesterol concentrations, low HDL-cholesterol concentrations, hypertension, smoking, diabetes, and obesity are associated with advanced atherosclerotic lesions and increased risk of clinically manifest atherosclerotic disease. Control of these risk factors is the major strategy for preventing atherosclerotic disease. To determine whether these risk factors also are associated with early atherosclerosis in young persons, we examined arteries and tissue from approximately 3000 autopsied persons aged 15-34 y who died of accidental injury, homicide, or suicide. The extent of both fatty streaks and raised lesions (fibrous plaques and other advanced lesions) in the right coronary artery and in the abdominal aorta was associated positively with non-HDL-cholesterol concentration, hypertension, impaired glucose tolerance, and obesity and associated negatively with HDL-cholesterol concentration. Atherosclerosis of the abdominal aorta also was associated positively with smoking. These observations indicate that long-range prevention of atherosclerosis and its sequelae by control of the risk factors for adult coronary artery disease should begin in adolescence and young adulthood.

Associations of coronary heart disease risk factors with the intermediate lesion of atherosclerosis in youth. The Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Research Group

The raised fatty streak (fatty plaque) is the gross term for the lesion intermediate between the juvenile (flat) fatty streak and the raised lesion of atherosclerosis. We measured the percentage of intimal surface involved with flat fatty streaks, raised fatty streaks, and raised lesions in the aortas and right coronary arteries of 2876 autopsied persons aged 15 through 34 years who died of external causes. Raised fatty streaks were present in the abdominal aortas of approximately 20% of 15- to 19-year-old subjects, and this percentage increased to approximately 40% for 30- to 34-year-old subjects. Raised fatty streaks were present in the right coronary arteries of approximately 10% of 15- to 19-year-old subjects, and this percentage increased to approximately 30% for 30- to 34-year-old subjects. The percent intimal surface involved with raised fatty streaks increased with age in both arteries and was associated with high non-high density lipoprotein (HDL) and low HDL cholesterol concentrations in the abdominal aorta and right coronary artery, with hypertension in the abdominal aorta, with obesity in the right coronary artery of men, and with impaired glucose tolerance in the right coronary artery. Associations of risk factors with raised fatty streaks became evident in subjects in their late teens, whereas associations of risk factors with raised lesions became evident in subjects aged >25 years. These results are consistent with the putative transitional role of raised fatty streaks and show that coronary heart disease risk factors accelerate atherogenesis in the second decade of life. Thus, long-range prevention of atherosclerosis should begin in childhood or adolescence.

Association of Coronary Heart Disease Risk Factors with microscopic qualities of coronary atherosclerosis in youth

BACKGROUND

This study examined whether atherosclerosis in young people is associated with the risk factors for clinical coronary heart disease (CHD). Methods and Results-Histological sections of left anterior descending coronary arteries (LADs) from 760 autopsied 15- to 34-year-old victims of accidents, homicides, and suicides were graded according to the American Heart Association (AHA) system and computerized morphometry. Risk factors (dyslipoproteinemia, smoking, hypertension, obesity, impaired glucose tolerance) were assessed by postmortem measurements. Approximately 2% of 15- to 19-year-old men and 20% of 30- to 34-year-old men had AHA grade 4 or 5 (advanced) lesions. No 15- to 19-year-old women had grade 4 or 5 lesions; 8% of 30- to 34-year-old women had such lesions. Approximately 19% of 30- to 34-year-old men and 8% of 30- to 34-year-old women had atherosclerotic stenosis > or =40% in the LAD. AHA grade 2 or 3 lesions (fatty streaks), grade 4 or 5 lesions, and stenosis > or =40% were associated with non-HDL cholesterol > or =4.14 mmol/L (160 mg/dL). AHA grade 2 or 3 lesions were associated with HDL cholesterol <0.91 mmol/L (35 mg/dL) and smoking. AHA grade 4 or 5 lesions were associated with obesity (body mass index > or =30 kg/m(2)) and hypertension (mean arterial pressure > or =110 mm Hg).

CONCLUSIONS

-Young Americans have a high prevalence of advanced atherosclerotic coronary artery plaques with qualities indicating vulnerability to rupture. Early atherosclerosis is influenced by the risk factors for clinical CHD. Long-range prevention of CHD must begin in adolescence or young adulthood.

Pathobiological determinants of atherosclerosis in youth (PDAY) cardiovascular specimen and data library

In 1985, investigators organized a multi-center study, Pathobiological Determinants of Atherosclerosis in Youth (PDAY), to examine the relationships of cardiovascular risk factors to atherosclerosis involving more than 3,000 young persons 15 through 34 years of age who died of external causes. Reports from the PDAY group confirmed that atherosclerosis begins in the teens and showed that the progression of the lesions is strongly influenced by the same risk factors that predict risk of clinically manifest coronary disease in middle-aged adults. The results emphasize the need for early and aggressive control of all risk factors in young persons for long-range prevention of coronary heart disease and related diseases. Recent funding by the Louisiana Cancer and Lung Trust Fund (LCLTF) has assisted Pathology at Louisiana State University Health Sciences Center (LSUHSC) in the following objectives: (1) maintaining this national research resources; (2) making the unique specimens available to interested investigators; and (3) continuing support for studies at LSUHSC which investigate the effects of smoking on the development of atherosclerotic lesions.

Dehydroepiandrosterone alters lipid profiles in Zucker rats

High free fatty acid (FFA) levels are common in obesity and in diseases such as diabetes that are associated with the obese state. Dehydroepiandrosterone (DHEA) decreases dietary fat consumption, body fat content, and insulin levels in the obese Zucker rat (ZR), a genetic model of human youth-onset obesity and type 2 diabetes mellitus. This study was conducted to investigate the effects of DHEA on lean and obese ZR serum, adipose, and hepatic tissue fatty acid (FA) profiles and serum FFA levels. Because DHEA is known to decrease fat consumption and body fat, we postulate that DHEA may also alter FA profiles and FFA levels of the obese ZR such that they more closely resemble the profiles and levels of their lean siblings. In this study there was a DHEA and a pair-fed (PF) group (n = 6) for 12 lean and 12 obese ZR. The diet of the treatment groups was supplemented with 0.6% DHEA, and PF groups were given the same average calories consumed by their corresponding DHEA group for 30 d. Fasted animals were sacrificed, and FA profiles and FFA levels were measured. Serum FFA levels were higher in obese (approximately 1 mmol/L) compared to lean rats (approximately 0.6 mmol/L). After 30 d of DHEA treatment, FFA levels were lower (P < 0.05) in both lean and obese groups. Although several significant differences in FA profile of serum, hepatic, and adipose lipid components were observed between lean and obese ZR, DHEA-related changes were only observed in the serum phospholipid (PL) and liver PL and triglyceride fractions. The slight but significant decrease in serum FFA levels may be reflected by changes in serum PL FA profiles. Specific hepatic FA profile alterations may be related to DHEA's known effects in inducing hepatic peroxisomes. We speculate that such FA changes may give insight into a mechanism for the action of DHEA.

Coronary calcification: insights from sudden coronary death victims

We studied 108 cases of sudden coronary death at autopsy. Any calcification was present in 55% of men and women under 40 years; all hearts showed some calcification by age 50 in men, and by age 60 in women. The only risk factor independently associated with increased calcification was diabetes mellitus, in women only. The degree of calcification was greatest for acute and healed plaque ruptures, and the least for plaque erosion. Calcification in coronary atherosclerosis appears to be delayed in women, is greatest in women diabetics, and is associated with one type of plaque instability, namely plaque rupture.

A comparison of the Framingham risk index, coronary artery calcification, and culprit plaque morphology in sudden cardiac death

BACKGROUND

Neither clinical prediction models nor noninvasive imaging tests that detect coronary artery calcification identify all patients who experience acute coronary events. Variations in culprit plaque morphology may account for these inaccuracies.

METHODS AND RESULTS

We compared the 10-year Framingham risk index, histologic coronary calcification, and culprit plaque morphology in 79 consecutive adults with sudden cardiac death. There was a modest relationship between the Framingham risk index and the extent of histologic coronary calcification (r=0.35, P=0.002). Agreement in risk classification between the histologic calcification score and the Framingham risk index occurred in 50 of 79 cases (63.3%, P=0. 039). Either a focus of coronary artery calcification >/=40 micromol/L (62% of cases) or a Framingham risk index score >/= average risk for age (62% of cases) were present in 66 of 79 (83.5%) cases. Cases with plaque erosion (n=22) had significantly less coronary calcification (P=0.003) and lower Framingham risk index (P=0.001) scores than stable (n=27) or ruptured (n=30) plaques. Fourteen of 22 (63.6%) cases of plaque erosion were classified as low risk by both the Framingham risk index and the histologic calcification score.

CONCLUSIONS

The prediction of sudden cardiac death using the Framingham risk index and the measurement of coronary calcification are distinct methods of assessing risk for sudden cardiac death. Excessive reliance on either method alone will produce errors in risk classification, particularly for patients at risk of plaque erosion, but their combination may be complementary.

Effects of coronary heart disease risk factors on atherosclerosis of selected regions of the aorta and right coronary artery. PDAY Research Group. Pathobiological Determinants of Atherosclerosis in Youth

We examined topographic distributions of atherosclerosis and their relation to risk factors for adult coronary heart disease in right coronary arteries and abdominal aortas of more than 2000 autopsied persons 15 through 34 years of age. We digitized images of Sudan IV-stained fatty streaks and of manually outlined raised lesions and computed the percent surface area involved by each lesion in each of 6 regions of each artery. In abdominal aortas of 15- to 24-year-old persons, fatty streaks involve an elongated oval area on the dorsolateral intimal surface and another oval area in the middle third of the ventral surface. Raised lesions in 25- to 34-year-old persons involve an oval area in the distal third of the dorsolateral intimal surface. In other areas of the abdominal aortas of older persons, fatty streaks occur but raised lesions are rare. In the right coronary arteries of 15- to 24-year-old persons, fatty streaks are most frequent on the myocardial aspect of the first 2 cm. Raised lesions follow a similar pattern in 25- to 34-year-old persons. High non-HDL cholesterol and low HDL cholesterol concentrations are associated with more extensive fatty streaks and raised lesions in all regions of both arteries. Smoking is associated with more extensive fatty streaks and raised lesions of the abdominal aorta, particularly in the dorsolateral region of the distal third of the abdominal aorta. Hypertension is not associated with fatty streaks in whites or blacks but is associated with more extensive raised lesions in blacks. Risk factor effects on arterial regions that are vulnerable to lesions are approximately 25% greater than risk factor effects assessed over entire arterial segments. These risk factor effects on vulnerable sites emphasize the need for risk factor control during adolescence and young adulthood to prevent or delay the progression of atherosclerosis.

Arterial remodeling in the left coronary system: the role of high-density lipoprotein cholesterol

OBJECTIVES

We sought to evaluate the plaque and patient variables related to arterial remodeling responses of early, de novo atherosclerotic lesions involving the left coronary artery.

BACKGROUND

Coronary artery remodeling is a lesion-specific process involving either enlargement or shrinkage of atherosclerotic coronary arteries. There are little histologic data available correlating plaque morphologic and patient clinical characteristics with the degree and type of arterial remodeling in early atherosclerosis.

METHODS

We studied 736 serial arterial sections from the left coronary system of 97 autopsy cases (mean age 33 +/- 11 years) by correlating the arterial remodeling response to plaque with demographic, serologic and histologic variables. Using the most proximal section as a reference, and considering the expected degree of internal elastic lamina tapering, remodeling was classified as positive (including neutral remodeling or compensatory enlargement) or negative.

RESULTS

Remodeling was classified as positive in 84.3% (compensatory in 30.6%) and negative in 15.7% of sections with an overall mean luminal stenosis of 10.4 +/- 9.9%. In the lesions with the greatest arterial cross-sectional narrowing from each case, compensatory enlargement was associated with higher high-density lipoprotein (HDL) cholesterol (59.4 +/- 27.2 mg/dl) compared with either neutral (49.3 +/- 15.5 mg/dl) or negative remodeling (30.4 +/- 5.2 mg/dl; p = 0.019). In subjects with advanced atherosclerosis (maximum American Heart Association histologic grade 5 atherosclerosis), there was a modest linear relationship between higher HDL cholesterol and the propensity for positive remodeling (r2 = 0.37; p = 0.025). On multivariate analysis, only HDL cholesterol was related to the arterial remodeling response.

CONCLUSIONS

Negative arterial remodeling occurs in early atherosclerosis. Higher HDL cholesterol may favor positive remodeling.

Apolipoprotein E and atherosclerosis in Greenland Inuit

Arterial, liver, and serum specimens were collected from Greenland Inuit at autopsy and apolipoprotein E genotyping was done on 42 females (mean age = 61.3 years) and 56 males (mean age = 56.8 years). Estimates of the allele frequencies of the apo E, derived from the observed frequencies of the six common apolipoprotein E genotypes, are E2: 0.015+/-0.009; E3: 0.776+/-0.030; and E4: 0.209+/-0.029. No significant difference was found between these frequencies and those previously reported for Greenland Inuit, Canadian Inuit, or Alaska natives; however, differences were observed in comparison with frequencies reported for Japan, Norway, Sweden, USA-Blacks and USA-Whites. Anthropometric data (body mass index, panniculus adiposus thickness), blood analyte levels (total serum cholesterol, HDL-cholesterol, LDL + VLDL-cholesterol, and glycohemoglobin), and prevalence and extent of atherosclerotic lesions in the aorta and coronary arteries were analyzed for any associations with apolipoprotein E genotype. The occurrence of apolipoprotein E2 alleles are very rare and the E4 alleles are slightly more frequent in the Greenland Inuit population as compared to other populations. No significant association between apolipoprotein E genotypes and the extent of atherosclerotic lesions in the aorta and coronary arteries were found, and there does not appear to be any strong evidence for an association of either serum lipids, glycohemoglobin levels, or adiposity measurements to apolipoprotein E genotype in Greenland Inuit.

Plaque rupture and sudden death related to exertion in men with coronary artery disease

CONTEXT

Exertion has been reported to acutely increase the risk of sudden coronary death, but the underlying mechanisms are unclear.

OBJECTIVE

To determine the frequency of plaque rupture in sudden deaths related to exertion compared with sudden deaths not related to exertion.

DESIGN

Autopsy survey. Coronary arteries were perfusion fixed and segments with more than 50% luminal narrowing were examined histologically. Ruptured plaques were defined as intraplaque hemorrhage with disruption of the fibrous cap and luminal thrombus. Exertion before death was determined by the investigator of the death.

SETTING

Medical examiner's office.

PATIENTS

A total of 141 men with severe coronary artery disease who died suddenly, including 116 whose deaths occurred at rest (mean [SD] age, 51 [11] years) and 25 who died during strenuous activity or emotional stress (age, 49 [9] years).

MAIN OUTCOME MEASURES

The frequency and morphology of plaque rupture was compared in men dying at rest vs those dying during exertion. Independent association of risk factors (total cholesterol, high-density lipoprotein cholesterol, glycosylated hemoglobin, cigarette smoking) in addition to acute exertion with plaque rupture were determined.

RESULTS

The mean (SD) number of vulnerable plaques in the coronary arteries of men in the exertional-death group was 1.6 (1.5) and in the at-rest group was 0.9 (1.2) (P=.03). The culprit plaque in men dying during exertion was plaque rupture in 17 (68%) of 25 vs 27 (23%) of 116 men dying at rest (P<.001). Hemorrhage into the plaque occurred in 18 (72%) of 25 men in the exertional-death group and 47 (41%) of 116 men in the rest group (P=.007). Histological evidence of acute myocardial infarction was present in 0 of 25 in the exertion group and in 15 (13%) of 116 in the rest group. Men dying during exertion had a significantly higher mean (SD) total cholesterol-high-density lipoprotein cholesterol ratio (8.2 [3.0]) than those dying at rest (6.2 [ 2.7]; P=.002), and the majority (21/25) were not conditioned. In multivariate analysis, both exertion (P=.002) and total cholesterol-high-density lipoprotein cholesterol ratio (P=.002) were associated with acute plaque rupture, independent of age and other cardiac risk factors.

CONCLUSION

In men with severe coronary artery disease, sudden death related to exertion was associated with acute plaque rupture.

Lipid and apolipoprotein predictors of atherosclerosis in youth: apolipoprotein concentrations do not materially improve prediction of arterial lesions in PDAY subjects. The PDAY Research Group

We compared serum lipid and apolipoprotein predictors of atherosclerosis in cases from the multicenter study, Pathobiological Determinants of Atherosclerosis in Youth (PDAY). The lipid measures included HDL cholesterol (HDL-C) and non-HDL-C, and the apolipoprotein measures included concentrations of apoA1, apoB, and Lp(a), and sizes of the apo(a) proteins. We tested whether the apolipoprotein measures predicted atherosclerotic lesions as well as the more traditional lipid measures. We estimated extent of lesions as fatty streaks or raised lesions (fibrous plaques, complicated or calcified lesions) in 3 sites: thoracic aorta, abdominal aorta, and right coronary artery. Neither apoA1 nor apoB measures were as strongly or consistently correlated with extent of lesions as the corresponding lipid measure (HDL-C and non-HDL-C, respectively). Beyond the basic model that included sex, age, race, smoking status, hypertension, and the lipid measures, apoA1 and apoB added only an average 1.3% increased explanatory ability to the model, whereas HDL-C plus non-HDL-C added an average 2.5%. The results suggest that the traditional lipid measures are more useful than apolipoprotein measures for detecting young persons at high risk of precocious atherosclerosis. Because of large racial differences, the two Lp(a)-related measures, Lp(a) concentrations and apo(a) size, were evaluated in blacks and whites separately. Under these circumstances, neither of the Lp(a)-related measures was strongly or consistently correlated with extent of lesions.

Prevalence and extent of atherosclerosis in adolescents and young adults: implications for prevention from the Pathobiological Determinants of Atherosclerosis in Youth Study

CONTEXT

Atherosclerosis, the underlying cause of coronary heart disease, has been shown to be present even in young adults.

OBJECTIVE

To document the extent and severity of atherosclerosis in adolescents and young adults in the United States.

DESIGN AND SETTING

The Pathobiological Determinants of Atherosclerosis in Youth Study, a multi-institutional autopsy study conducted in US medical centers. Subjects A total of 2876 study subjects, between 15 and 34 years old, black and white, men and women, who died of external causes and underwent autopsy between June 1, 1987, and August 31, 1994.

MAIN OUTCOME MEASURES

Extent, prevalence, and topography of atherosclerotic lesions.

RESULTS

Intimal lesions appeared in all the aortas and more than half of the right coronary arteries of the youngest age group (15-19 years) and increased in prevalence and extent with age through the oldest age group (30-34 years). Fatty streaks were more extensive in black subjects than in white subjects, but raised lesions did not differ between blacks and whites. Raised lesions in the aortas of women and men were similar, but raised lesions in the right coronary arteries of women were less than those of men. The prevalence of total lesions was lower in the right coronary artery than in the aorta, but the proportion of raised lesions among total lesions was higher in the right coronary artery than in the aorta.

CONCLUSIONS

Atherosclerosis begins in youth. Fatty streaks and clinically significant raised lesions increase rapidly in prevalence and extent during the 15- to 34-year age span. Primary prevention of atherosclerosis, as contrasted with primary prevention of clinically manifest atherosclerotic disease, must begin in childhood or adolescence.

Effect of risk factors on the mechanism of acute thrombosis and sudden coronary death in women

BACKGROUND

Traditional risk factors have been linked to atherosclerotic heart disease in women. However, the effect of risk factors and menopausal status on the mechanism of sudden coronary death is unknown.

METHODS AND RESULTS

We examined 51 cases of sudden coronary death and 15 hearts from women who died of trauma. Coronary deaths were divided into four mechanisms of death: ruptured plaque with acute thrombus (n = 8), eroded plaque with acute thrombus (n = 18), stable plaque with healed infarct (n = 18), and stable plaque without infarction (n = 7). Vulnerable plaques prone to rupture were defined as those with a thin, fibrous cap infiltrated by macrophages and were quantitated in coronary deaths and control subjects. Total cholesterol (TC), HDL cholesterol, glycosylated hemoglobin, cigarette smoking, and hypertension were determined in each case. Compared with control subjects, women with plaque ruptures had elevated TC (270 +/- 55 versus 194 +/- 44 mg/dL, P = 0.002), and those with erosions were more likely to be smokers (78% versus 33%, P = 0.01). Women with stable plaque and healed infarct had elevated glycosylated hemoglobin (10.2 +/- 5.0% versus 6.4 +/- 0.4% in control subjects, P = 0.001) and were more likely to be hypertensive (50% versus 15% in control subjects, P = 0.03). By multivariate analysis, cigarette smoking was associated with plaque erosion (P = 0.03, odds ratio [OR] 21), glycoslyated hemoglobin with stable plaque and healed infarct (P = 0.03, OR 41), TC with plaque rupture (P = 0.02, OR 7), and hypertension with stable plaque with healed infarct (P = 0.02, OR 15). Seven of 8 plaque ruptures occurred in women > 50 years of age versus 3 of 18 erosions (P = 0.001). In cases of coronary death, vulnerable plaques were associated with elevated cholesterol (P = 0.002) and age > 50 years (P = 0.002), independent of other risk factors.

CONCLUSIONS

In women, traditional risk factors have distinct effects on the mechanisms of sudden coronary death, which vary by menopausal status. Effective risk factor modification may therefore differ between younger and older women and may be targeting different mechanisms of plaque instability.

Coronary risk factors and plaque morphology in men with coronary disease who died suddenly

BACKGROUND

Cigarette smoking and abnormal serum cholesterol concentrations are risk factors for acute coronary syndromes, but the underlying mechanisms are poorly understood. We studied whether cigarette smoking and abnormal cholesterol values may precipitate acute coronary thrombosis and sudden death resulting from either rupture of vulnerable coronary plaques or erosion of plaques.

METHODS

We examined the hearts of 113 men with coronary disease who had died suddenly and also analyzed their coronary risk factors. We found an acute coronary thrombus in each of 59 men, and severe narrowing of the coronary artery by an atherosclerotic plaque without acute thrombosis (stable plaque) in 54. Cases of acute thrombosis were divided into two groups: 41 resulting from rupture of a vulnerable plaque (a thin fibrous cap overlying a lipid-rich core), and 18 resulting from the erosion of a fibrous plaque rich in smooth-muscle cells and proteoglycans. Vulnerable plaques that had not ruptured were counted in each heart.

RESULTS

Cigarette smoking was a risk factor in 44 (75 percent) of the men with acute thrombosis, as compared with 22 (41 percent) of the men with stable plaques (P<0.001). The mean (+/-SD) ratio of serum total cholesterol to high-density lipoprotein (HDL) cholesterol was markedly elevated in the men who died of acute thrombosis with plaque rupture (mean, 8.5+/-4.0) but only mildly elevated in the men without acute thrombosis (5.5+/-2.4; P<0.001) and in the men with thrombi overlying eroded plaques (5.0+/-1.8; P<0.001). Multivariate analysis showed an association between an elevated ratio of serum total cholesterol to HDL cholesterol and the presence of vulnerable plaques (P<0.001).

CONCLUSIONS

Among men with coronary disease who die suddenly, abnormal serum cholesterol concentrations - particularly elevated ratios of total cholesterol to HDL cholesterol - predispose patients to rupture of vulnerable plaques, whereas cigarette smoking predisposes patients to acute thrombosis.

Atherosclerosis in youth: are hypertension and other coronary heart disease risk factors already at work?

The purposes of this review were to describe the natural history of atherosclerosis in youth, discuss the role of adult coronary heart disease (CHD) risk factors in the development of atherosclerosis-particularly in the young- and present the relationship between atherosclerosis and hypertension. Evidence is presented that, by age 15 years, 100% of the youth have aortic atherosclerosis and about one-half have coronary atherosclerosis. Risk factors for adult CHD, including lipoproteins, smoking, glycohemoglobin (a marker for diabetes), obesity, and hypertension, are associated with extent and prevalence of atherosclerosis in young people. Hypertension seems to play its role mainly by converting early atherosclerotic lesions (fatty streaks) to more advanced lesions (raised lesions).

Effects of serum lipoproteins and smoking on atherosclerosis in young men and women. The PDAY Research Group. Pathobiological Determinants of Atherosclerosis in Youth

Atherosclerosis begins in childhood and progresses from fatty streaks to raised lesions in adolescence and young adulthood. A cooperative multicenter study (Pathobiological Determinants of Atherosclerosis in Youth [PDAY]) examined the relation of risk factors for adult coronary heart disease to atherosclerosis in 1079 men and 364 women 15 through 34 years of age, both black and white, who died of external causes and were autopsied in forensic laboratories. We quantitated atherosclerosis of the aorta and right coronary artery as the extent of intimal surface involved by fatty streaks and raised lesions and analyzed postmorterm serum for lipoprotein cholesterol and thiocyanate (as an indicator of smoking). The extent of intimal surface involved with both fatty streaks and raised lesions increased with age in all arterial segments of all sex and race groups. Women had a greater extent of fatty streaks in the abdominal aorta than men, but women and men had about an equal extent of raised lesions. Women and men had a comparable extent of fatty streaks in the right coronary artery, but women had about half the extent of raised lesions. Blacks had a greater extent of fatty streaks than whites, but blacks and whites had a similar extent of raised lesions. VLDL plus LDL cholesterol concentration was associated positively and HDL cholesterol was associated negatively with the extent of fatty streaks and raised lesions in the aorta and right coronary artery. Smoking was associated with more extensive fatty streaks and raised lesions in the abdominal aorta. All three risk factors affected atherosclerosis to about the same degree in both sexes and both races. Primary prevention of atherosclerosis by controlling these adult coronary heart disease risk factors is applicable to young men and women and to young blacks and whites.

Racial comparison of p53 alterations in breast cancer: difference in prognostic value

A significant difference in breast cancer survival between blacks and whites has been observed in the United States. Biological variation between races has been suggested to explain the difference. We investigated the difference by comparing the prognostic value of p53 alterations (mutations and protein accumulation) between black and white breast cancer patients. Black, but not white, patients with p53 mutations had a significantly poorer survival than those without p53 mutations (p < 0.05). In contrast, white, but not black, patients having tumors with p53 protein accumulation tended to have a poorer survival than those without accumulation of p53 protein (p = 0.058). Among patients who died of breast cancer, blacks were often to have p53 mutations without protein accumulation, and whites frequently had p53 protein accumulation without mutations. The racial disparities in the associations of p53 alterations with breast cancer survival could have clinical implications in terms of treatment management.

Renovasculopathies of nephrosclerosis in relation to atherosclerosis at ages 25 to 54 years

Renovasculopathies of hypertension include arteriolar hyalinization and arterial intimal fibroplasia. Atherosclerotic features of coronary arteries and aorta include fatty streaks and raised lesions. Data were obtained from a series of 573 autopsies of black and Caucasian males and females aged 25 to 54 years, who died of violent and natural causes unrelated to atherosclerosis. Analysis showed positive correlations of coronary and aortic raised lesions with arteriolar hyalinization. Arterial intimal fibroplasia correlated positively with raised lesions in the aorta but only weakly and inconsistently in the coronary arteries. The extent of fatty streaks in the coronaries, as in the aorta, did not correlate with either form of renovasculopathy. These results provide evidence that hyalinization of renal arterioles may be a marker for young people who have the most advanced coronary atherosclerosis, and who therefore have an early start upon a course toward coronary heart disease later in life.

Effect of beta-carotene supplementation on serum alpha-tocopherol concentration

Conflicting reports of the effects of beta-carotene supplementation on serum alpha-tocopherol concentration led us to evaluated serum alpha-tocopherol in subjects with and without beta-carotene (30 mg/day) supplementation for up to 2 years duration in an ongoing chemoprevention trial. No adverse effect has been observed at any of the time periods examined.

Prominence of coronary arterial wall lipids in human heart allografts. Implications for pathogenesis of allograft arteriopathy

Transplant arteriopathy is a major late complication in human heart allograft recipients and the pathogenesis of such arteriopathy remains uncertain. The degree to which lipids and atheromata are involved in the arteriopathic lesions remains unsettled, and there is uncertainty regarding the significance of insudation or retention of lipids within the coronary artery walls of transplanted hearts. On current immunosuppressive regimens, most patients experience an increased serum total cholesterol and low-density lipoprotein cholesterol after transplant. Elevation of these blood lipids has an undetermined relationship to arteriopathy. We carried out morphological, morphometric, immunohistochemical, ultrastructural, and biochemical studies of particular coronary artery segments from 23 unselected explant or autopsy allografts and donor age-matched native coronary controls. Patients died of cardiac and non-cardiac reasons over a period of 4 to 1610 days after transplant. Atheromata were frequent, and diffuse intra- and extra-cellular accumulation of lipids in both intimal and medial walls was documented by oil red O positivity, immunohistochemical staining (muscle-specific alpha-actin), transmission and scanning electron microscopy, and biochemical analysis. Mean total cholesterol, esterified cholesterol, free cholesterol, and phospholipid content (microgram/cm2 intimal surface area) and concentration (microgram/mg dry defatted weight) in arteriopathic coronaries were > 10-fold higher than in comparable native coronary segments. Extent of lipids in the arterial walls was highly correlated with digitized percent luminal narrowing, mean daily and cumulative cyclosporin dose, and mean cumulative prednisone dose. Our data suggests strongly that lipid accumulation is an important early and persistent phenomenon in the development of transplant arteriopathy.

Environmental and genetic risk factors in early human atherogenesis: lessons from the PDAY study. Pathobiological Determinants of Atherosclerosis in Youth

A multi-institutional study 'Pathobiological Determinants of Atherosclerosis in Youth' (PDAY) was initiated to document the natural history of atherosclerosis, its relationship to risk factors, and pathobiology of lesion development in young subjects. Pathology laboratories in nine centers collected arteries and tissues from over 2000 persons from 15 through 34 years of age whose deaths were attributed to homicides, accidents, or suicides. Arteries were evaluated for lesions, and risk factors were analyzed in a central laboratory. Post-mortem risk factors included serum lipoproteins, serum thiocyanate (smoking), glycohemoglobin (diabetes), thickness of panniculus adiposus (obesity), small renal artery changes (hypertension) and apoprotein isoforms. This study documents the development of atherosclerosis at an early age. It also shows that the recognized risk factors for coronary heart disease are associated with lesion development in the arteries of these young subjects. The PDAY study has a counterpart in Japan where the development of atherosclerosis has been studied in young subjects. This Japanese study, in a population in which coronary heart disease has not yet become a major epidemic, has findings quite similar to the findings from the PDAY study. Studies of atherosclerosis in both Japan and the USA provide strong justification for reducing risk factors in young persons.

Apolipoprotein E and atherosclerosis in Alaska Natives

Arterial, liver, and serum specimens were collected from 130 Alaska Natives who underwent forensic necropsy (mean age, 36.9 years; age range, 9-85 years; 38 females and 92 males). Based upon the observed frequencies of the six common apo E genotypes, the estimates of the relative frequencies of the corresponding alleles in the population are 0.020 +/- 0.009 for E2, 0.787 +/- 0.026 for E3 and 0.193 +/- 0.025 for E4. Analysis showed significant differences, by apo E genotype, in the extent of total surface lesion involvement in both the right and left coronary arteries. In all but the abdominal aorta, the pattern of lesion involvement by genotype is consistent with a decrease in lesions for genotypes with the E2 allele and an increase in lesions for the genotypes with the E4 allele, relative to the E3 homozygotes. After adjustment for low + very low density lipoprotein cholesterol (LDL + VLDL-C), the differences fell below statistically significant levels. Analysis by genotype of total serum cholesterol, high density lipoprotein cholesterol (HDL-C) and LDL + VLDL-C showed no statistically significant differences in analyte levels among genotypes. However, evidence is seen of a pattern in which total cholesterol and VLDL + LDL-C is less in genotypes with the E2 allele and greater in those with the E4 allele. We conclude that there does appear to be an effect by apo E genotype upon extent of atherosclerosis in the coronary arteries of Alaska Natives and this effect is likely due to the previously reported effect of apo E polymorphisms on serum cholesterol, particularly LDL + VLDL-C.

Relation of glycohemoglobin and adiposity to atherosclerosis in youth. Pathobiological Determinants of Atherosclerosis in Youth (PDAY) Research Group

In a cooperative multicenter study (Pathobiological Determinants of Atherosclerosis in Youth, PDAY) of 1532 young persons 15 through 34 years of age who died of external causes and were autopsied in medical examiners' laboratories, we quantified atherosclerosis of the aorta and the right coronary artery. We analyzed postmortem blood cells for glycohemoglobin and postmortem serum for lipoprotein cholesterol and thiocyanate (as an indicator for smoking). We measured the thickness of the panniculus adiposus and the body mass index (weight per height squared) as indicators of adiposity. Glycohemoglobin levels exceeding 8% were associated with substantially more extensive fatty streaks and raised lesions in the right coronary artery in persons more than 25 years of age and with more extensive raised lesions in the aorta in persons more than 30 years of age. Both thickness of the panniculus adiposus and body mass index were associated with more extensive fatty streaks and raised lesions in the right coronary artery. The associations of atherosclerotic lesions with glycohemoglobin and adiposity were not explained by a less favorable lipoprotein profile or smoking. The results show that atherosclerosis in young adults is associated with the prediabetic or early diabetic state, as indicated by elevated glycohemoglobin levels, and with obesity.

Long-term induction and regression of diet-induced atherosclerotic lesions in rhesus monkeys. II. Morphometric evaluation of lesions by light microscopy in coronary and carotid arteries

Atherosclerotic lesions were induced in rhesus monkeys (Macaca mulatta) by feeding them a high-saturated fatty acid and high-cholesterol diet. After 5.4 years the extent of lesions in three major coronary arteries and the right carotid artery was evaluated morphometrically by light microscopy in one group of animals (group P). The remaining animals were switched to a low-cholesterol diet that remained high in saturated fatty acids and provided the same percentage of total calories as did the atherogenic diet. Lesion regression was then evaluated in one group of monkeys 1.9 years (group R4) and in another group of monkeys 3.7 years (group R5) after withdrawal of cholesterol alone from the diet. In group P, the mean intimal thickness varied between 26 and 47 microns, maximum intimal thickness between 70 and 92 microns, and luminal reduction between 9% and 12% in the three major coronary arteries. Luminal reduction varied between 1% and 11% in right carotid artery segments. After 1.9 years of consuming the basal diet, group R4 animals were no different from group P animals with respect to morphometric measures. Total intimal and medial areas of the left anterior descending (LAD) coronary artery in groups P and R4 were also similar. In contrast, after 3.7 years of consuming the basal diet, group R5 animals showed consistently although not statistically significantly lower values than those in group P for the morphometric measures in coronary arteries and total intimal area in the LAD. Similar results were obtained for the common carotid and external carotid arteries. Thus, our study shows that long-term diet-induced lesions in coronary arteries and in common and external segments of the right carotid artery regressed only when the animals were fed the basal diet for 3.7 years. We conclude that atherosclerotic lesions induced in coronary and carotid arteries can regress toward normal to a certain extent, but they require a longer time for regression than do other arterial segments. These findings support the results of clinical trials in human subjects.

Ascorbic acid, Helicobacter pylori and Lewis phenotype among blacks and whites in New Orleans

Gastric juice ascorbic acid concentrations were examined in black and white patients. Significantly lower concentrations were found in blacks, in the absence of a significant difference in the plasma concentration of vitamin C between races. Blacks had higher prevalence of Helicobacter pylori infection, higher gastric pH, more severe acute and chronic inflammation of the gastric mucosa and higher frequency of Lewis (a-b-) phenotype. Although most of these factors have been related to low ascorbic acid levels in gastric juice, none of them could account entirely for the difference between races either individually or after joint consideration. These observations may help to explain the high incidence of gastric carcinoma among the black population in southern Louisiana.

Long-term induction and regression of diet-induced atherosclerotic lesions in rhesus monkeys. I. Morphological and chemical evidence for regression of lesions in the aorta and carotid and peripheral arteries

Atherosclerotic lesions were induced in rhesus monkeys by feeding a high-saturated fatty acid and high-cholesterol diet. After 5.4 years the extent of fatty streaks and raised lesions was evaluated in one group of animals (group P) by visual estimation in 10 arterial segments and chemically in four arterial segments. The remaining animals were switched to a basal regression diet low in cholesterol but high in saturated fatty acids for up to 3.7 years. Regression of lesions was evaluated in one group for 1.9 years (group R4) and in another for 3.7 years (group R5) after deleting cholesterol from the diet. The atherogenic diet increased serum cholesterol levels in all animals from a mean of 150 mg/dL to a mean of about 430 mg/dL. The atherogenic diet produced lesions in group P in all arterial segments (involving up to 50% of the arterial intimal surface) and increased cholesterol content in four arterial segments (varying between 443 and 506 micrograms/cm2). Switching to the basal regression diet decreased serum cholesterol levels to normal after 12 to 18 weeks. The switch to the basal diet significantly decreased the extent of fatty streaks in most arterial segments in both groups. Although differences in the mean extent of raised lesions among groups were not statistically significant, 7 of 10 arterial segments in group R4 and 9 of 10 segments in group R5 showed a lesser extent of raised lesions than in group P. Cholesterol content was lower (P < .05) in all four arterial segments in group R5 than in group P.(ABSTRACT TRUNCATED AT 250 WORDS)

Nephrosclerosis, glycohemoglobin, cholesterol, and smoking in subjects dying of coronary heart disease

Subjects dying of coronary heart disease (CHD) were compared with subjects in a control (basal) group in two series of forensic autopsies. Serum cholesterol assessed in postmortem heart blood was significantly greater in the CHD than in the basal group. CHD subjects were smokers more often than basal subjects, as determined from postmortem serum thiocyanate levels, but the statistical significance is ambiguous (P < 0.06). After exclusion of overt diabetics, a stepwise increase in the percentage of subjects with CHD was observed throughout the normal range for glycohemoglobin. Fibroplasia of small renal arteries, the most reliable postmortem proxy for hypertension, did not differ between CHD and basal groups. These results suggest that young (mean age 49.2 yr) black and white men and women classified from autopsy findings as having CHD as cause of death are often not hypertensive, but instead tend to be hyperlipidemic and glucose intolerant. A surprising result was that arteriolar hyalinization and arterial fibroplasia of the renal cortex often failed to parallel each other between groups of subjects. This was true in comparisons between black and white, male and female, blood cholesterol and glycohemoglobin groupings, and between CHD and basal subjects. This outcome suggests that hyalinization of renal arterioles is an especially reliable marker for CHD and that this association may not be mediated entirely through high blood pressure.

Vitamin C concentration in gastric juice before and after anti-Helicobacter pylori treatment

OBJECTIVES

To investigate the change of vitamin C concentration (ascorbic and dehydroascorbic acid) in gastric juice after anti-Helicobacter pylori treatment, and to relate any observed change to gastric pH, inflammatory compromise of the gastric mucosa, plasma vitamin C concentration, and smoking habits.

METHODS

Plasma and gastric juice vitamin C, fasting gastric juice pH, gastric histology, and smoking status were studied in 70 patients with H. pylori-associated gastritis before and after therapy.

RESULTS

Gastric juice ascorbic acid increased significantly after H. pylori clearance. For the most part, this change was confined to patients who experienced reduction of gastric pH. It was also related to improvement of the compromise of the gastric epithelium, reduction of the proportion of vitamin C composed by dehydroascorbic acid, and increase of the gastric juice/plasma vitamin C concentration gradient. Smokers had lower vitamin C concentrations in plasma and gastric juice before and after H. pylori clearance than nonsmokers.

CONCLUSIONS

The findings are consistent with a causal association between H. pylori infection and low ascorbic acid levels in gastric juice, and support two mechanisms for this association: increased oxidation and a decreased secretion of ascorbic acid.

Atherosclerosis in young white males: arterial collagen and cholesterol

As part of a multicenter study on atherosclerosis, we examined defined segments of thoracic and abdominal aortas from 118 white males, age 15-34 years, who died from external causes. One half of each aorta specimen was graded for lesions. Intima-media preparations were assayed for collagen and cholesterol in two standardized regions (dorsal and ventral) derived from the alternate half of each segment. Even though the mean extent of intimal surface involvement with raised lesions remained minimal (0-6%), the data revealed a remarkable transition in vessel wall chemistry over this time span. For example, the amount of collagen per unit surface area increases with age in all vessel segments except the ventral domain of the thoracic aorta. The amount of collagen as a percent of total vessel protein rises with age only in the ventral and dorsal regions of the abdominal aorta. Free and esterified cholesterol levels per unit surface area increase with age in all vessel segments. There is a significant correlation between collagen and esterified cholesterol per unit surface area in all vessel regions with the exception of the abdominal ventral segment. In the latter segment increases in collagen per unit surface area occur without a corresponding increase in cholesterol level suggesting that connective tissue proliferation may actually precede lipid deposition in the genesis of atherosclerosis. Esterified cholesterol is present at higher levels in the dorsal domains of the thoracic and abdominal aortas than in the ventral domains. These findings provide chemical data confirming that the dorsal domains is the most lesion-prone region of these vessel segments.(ABSTRACT TRUNCATED AT 250 WORDS)