Serum lipids and fatty acids in ischemic strokes

Comparison of circulating lipid profiles, D-dimer and fibrinogen levels between hypertensive patients with and without stroke

BACKGROUND

Stroke is one of the leading causes of global mortality and disability, particularly in hypertensive patients. This study aimed to compare lipid profile, fibrinogen, and D-dimer levels between hypertensive patient with and without stroke.

METHODS

This was a facility-based cross-sectional study conducted from November 2022 to January 2023 among 115 hypertensive patients (70 patients without stroke and 45 with stroke) who had follow-up at Yikatit 12 Hospital Medical College, Ethiopia. All data analyses were done using SPSS version 25.0 and comparisons of variables between groups were made using the Chi-square test, independent sample t-test, and Mann-Whitney U test. Multiple logistic regression analysis was done to identify predictors of stroke among hypertensive patients. A p-value <0.05 was assumed to be statistically significant for all statistical tests.

RESULTS

Significantly elevated levels of TC, LDL-C, D-DI, and fibrinogen were observed in the stroke group than in the non-stroke group (p-value<0.05). The mean values of TC, D-DI, and fibrinogen were significantly higher in patients with ischemic stroke compared to those with hemorrhagic stroke. Duration of hypertension (AOR: 1.21; CI: 1.10, 2.09), TC (AOR:1.07; CI: 1.01, 1.22), D-DI (AOR: 1.15; CI: 1.05, 1.69) and fibrinogen (AOR:1.19; CI: 1.10, 2.89) were identified to be independent predictors of stroke in hypertensive patients.

CONCLUSION

The circulating levels of TC, LDL-C, D-DI and fibrinogen in hypertensive patients with stroke were significantly higher than in those without stroke. But only TC, D-DI, and fibrinogen were found to be predictors of stroke in hypertensives. Considerably higher TC, D-DI, and fibrinogen levels were also seen in patients with ischemic stroke than in those with hemorrhagic stroke. This confirms the key roles of dyslipidemia (hypercholesterolemia) and aberrant hemostatic activation to stroke development, notably ischemic stroke.

Early Warning of Ischemic Stroke Based on Atherosclerosis Index Combined With Serum Markers

CONTEXT

Ischemic stroke (IS) is a serious public health problem worldwide, threatening human life and health. Atherosclerosis is the cause of stroke. At present, there are few selective indexes that can be used to evaluate atherosclerosis in the clinic; providers rely mainly on the atherosclerotic index (AI). Disturbance of lipid metabolism is considered to be a key event leading to IS.

OBJECTIVE

The purpose of this study was to discover potential biomarkers in the serum of atherosclerosis-induced IS, combined with the AI to provide early warning for the diagnosis of IS.

METHODS

In this study, we used nontargeted metabolomics based on ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) to measure the changes in serum metabolites in a group of patients with IS. To verify the reproducibility of candidate biomarkers in the population, we expanded the sample size.

RESULTS

Five metabolites were identified, including sphingomyelin (18:0/14:0), 1-Methylpyrrolinium, PC (18:0/18:0), LysoPC (18:0/0:0), and PC (18: 2/18:2). The combination of these 5 metabolic markers has good diagnostic and predictive ability, and the change level of these metabolites is significantly related to IS. Our results also indicate that changes in glycerophospholipid metabolism may indicate an early risk of IS development.

CONCLUSION

These findings may contribute to the development of new diagnostic methods of potential biomarkers in serum combined with the AI, thereby providing early warning for the diagnosis of atherosclerosis-induced IS, and may provide a new insights for pathogenesis in IS.

Metabolomics and metabolites in ischemic stroke

Stroke is a major reason for disability and the second highest cause of death in the world. When a patient is admitted to a hospital, it is necessary to identify the type of stroke, and the likelihood for development of a recurrent stroke, vascular dementia, and depression. These factors could be determined using different biomarkers. Metabolomics is a very promising strategy for identification of biomarkers. The advantage of metabolomics, in contrast to other analytical techniques, resides in providing low molecular weight metabolite profiles, rather than individual molecule profiles. Technically, this approach is based on mass spectrometry and nuclear magnetic resonance. Furthermore, variations in metabolite concentrations during brain ischemia could alter the principal neuronal functions. Different markers associated with ischemic stroke in the brain have been identified including those contributing to risk, acute onset, and severity of this pathology. In the brain, experimental studies using the ischemia/reperfusion model (IRI) have shown an impaired energy and amino acid metabolism and confirmed their principal roles. Literature data provide a good basis for identifying markers of ischemic stroke and hemorrhagic stroke and understanding metabolic mechanisms of these diseases. This opens an avenue for the successful use of identified markers along with metabolomics technologies to develop fast and reliable diagnostic tools for ischemic and hemorrhagic stroke.

GC-MS-Based Metabolomics to Reveal the Protective Effect of Gross Saponins of Tribulus terrestris Fruit against Ischemic Stroke in Rat

Stroke is one of the most common neurological disorders and seriously threatens human life. Gross saponins of Tribulus terrestris fruit (GSTTF) are used for neuroprotective treatment on convalescents of ischemic stroke. However, the therapeutic effects and mechanisms have not yet well understood, especially from the metabolic perspective. In this study, the protective effect of GSTTF on ischemic stroke in a middle cerebral artery occlusion (MCAO) rat model was investigated by the GC-MS-based metabolomics approach. 2,3,5-triphenyltetrazolium chloride (TTC) staining of brain tissues showed that GSTTF significantly reduced the infarct area after MCAO surgery. Metabolomic profiling showed a series of metabolic perturbation occurs in ischemic stroke compared with sham group. GSTTF can reverse the MCAO-induced serum metabolic deviations by regulating multiple metabolic pathways including fatty acids metabolism, amino acids metabolism, and carbohydrates metabolism. The current study provided a useful approach for understanding the mechanism of MCAO-induced ischemic stroke and a reliable basis for evaluating the efficacy of GSTTF in the treatment of ischemic stroke.

Arachidonic Acid and Cerebral Ischemia Risk: A Systematic Review of Observational Studies

Background

Arachidonic acid (ARA) is a precursor of various lipid mediators. ARA metabolites such as thromboxane A₂ cause platelet aggregation and vasoconstriction, thus may lead to atherosclerotic disease. It is unclear whether dietary ARA influences the ARA-derived lipid mediator balance and the risk for atherosclerotic diseases, such as cerebral ischemia. Considering the function of ARA in atherosclerosis, it is reasonable to focus on the atherothrombotic type of cerebral ischemia risk. However, no systematic reviews or meta-analyses have been conducted to evaluate the effect of habitual ARA exposure on cerebral ischemia risk. We aimed to systematically evaluate observational studies available on the relationship between ARA exposure and the atherothrombotic type of cerebral ischemia risk in free-living populations.

Summary

The PubMed database was searched for articles registered up to June 24, 2014. We designed a PubMed search formula as follows: key words for humans AND brain ischemia AND study designs AND ARA exposure. Thirty-three articles were reviewed against predefined criteria. There were 695 bibliographies assessed from the articles that included both ARA and cerebral ischemia descriptions. Finally, we identified 11 eligible articles and categorized them according to their reporting and methodological quality. We used the Strengthening the Reporting of Observational Studies in Epidemiology Statement (STROBE) checklist to score the reporting quality. The methodological quality was qualitatively assessed based on the following aspects: subject selection, ARA exposure assessment, outcome diagnosis, methods for controlling confounders, and statistical analysis. We did not conduct a meta-analysis due to the heterogeneity among the studies. All eligible studies measured blood ARA levels as an indicator of exposure. Our literature search did not identify any articles that evaluated dietary ARA intake and tissue ARA as assessments of exposure. Seven of the 11 eligible articles were considered to be of low quality. No articles reported a dose-dependent positive association between an increased cerebral ischemia risk and ARA exposure. However, most studies did not assess the risk in each subtype of cerebral ischemia, thus various etiological types of cerebral ischemia risk were involved in their results.

Key Messages

We did not find a positive association between ARA exposure and cerebral ischemia risk. Eligible studies reported inconsistent findings: cerebral ischemia risk did not change or significantly decreased. We could not draw any conclusions due to the limited number of eligible high-quality studies. Further evidence from well-designed observational studies is required. Simultaneously, in order to develop effective preventive measures against cerebral ischemia, it is imperative to establish standardized definitions, nomenclatures, classifications, and diagnostic procedures.

Serum fatty acids and incidence of ischemic stroke among postmenopausal women

BACKGROUND AND PURPOSE

Although studies have linked types of fatty acids with coronary heart disease, data on individual fatty acids and risk of ischemic stroke are limited. We aimed to examine the associations between serum fatty acid concentrations and incidence of ischemic stroke and its subtypes.

METHODS

We conducted a prospective case-control study nested in the Women's Health Initiative Observational Study cohort of postmenopausal US women aged 50 to 79 years. Between 1993 and 2003, incident cases of ischemic stroke were matched 1:1 to controls on age, race, and length of follow-up (964 matched pairs). Conditional logistic regression was used to estimate odds ratios and 99.9% confidence intervals (CI) for ischemic stroke and its subtypes.

RESULTS

The multivariable-adjusted odds ratios and 99.9% CI of ischemic stroke associated with a 1-SD increment in serum fatty acid concentration were 1.38 (99.9% CI, 1.05-1.83) for linoelaidic acid (18:2tt, SD=0.04%), 1.27 (99.9% CI, 1.06-1.51) for palmitic acid (16:0, SD=2.74%), 1.20 (99.9% CI, 1.01-1.43) for oleic acid (18:1n9, SD=2.32%), 0.72 (99.9% CI, 0.59-0.87) for docosapentaenoic acid (22:5n3, SD=0.18%), 0.72 (99.9% CI, 0.59-0.87) for docosahexaenoic acid (22:6n3, SD=0.91%), and 0.81 (99.9% CI, 0.67-0.98) for arachidonic acid (20:4n6, SD=2.02%). These associations were generally consistent for atherothrombotic and lacunar stroke but not cardioembolic stroke.

CONCLUSIONS

These findings suggest that individual serum trans, saturated, and monounsaturated fatty acids are positively associated with particular ischemic stroke subtypes, whereas individual n3 and n6 polyunsaturated fatty acids are inversely associated.

Plasma phospholipid fatty acid composition in ischemic stroke: importance of docosahexaenoic acid in the risk for intracranial atherosclerotic stenosis

OBJECTIVE

While data on the relationship between fatty acid (FA) composition and the risk for total stroke have accumulated, the association between FA composition and the risk for intracranial atherosclerotic stenosis (ICAS) has never been studied. We compared plasma phospholipid FA composition between non-stroke control and ischemic stroke in Korean population, to discern the FA that distinguishes ICAS from total ischemic stroke patients.

METHODS

Non-stroke controls (n = 215) and stroke patients (no cerebral atherosclerotic stenosis, NCAS: n = 144 and ICAS: n = 104) were finally included in the analysis. Plasma phospholipid FA compositions were analyzed.

RESULTS

Age, coexistence of hypertension/diabetes were significantly different among the groups. Phospholipid FA compositions were significantly different between non-stroke control and ischemic stroke patients, and interestingly, between NCAS and ICAS in stroke patients. Pattern analysis showed that docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), the ω3-polyunsaturated FAs were important FAs in distinguishing NCAS and ICAS in strokes. Particularly, the risk of ICAS was inversely associated with levels of DHA contents in phospholipids (OR: 0.590, 95% CI: 0.350-0.993, p < 0.05), indicating that the risk may be increased at lower levels of DHA contents.

CONCLUSION

DHA and EPA are important FAs for distinguishing NCAS and ICAS in strokes. Additionally, the risk of ICAS was inversely associated with the levels of phospholipid DHA, which indicates that sufficient amounts of DHA in plasma or in diet may reduce the risk of ICAS.

Trans fat, aspirin, and ischemic stroke in postmenopausal women

OBJECTIVE

To examine the associations between dietary fat intake and ischemic stroke among postmenopausal women.

METHODS

We conducted a prospective cohort study of 87,025 generally healthy postmenopausal women (age, 50-79 years) enrolled in the Women's Health Initiative Observational Study. Repeated and validated dietary assessments were done using a self-administered food frequency questionnaire. We used Cox proportional hazards models to estimate hazard ratios (HRs) of ischemic stroke based on quintiles of the cumulative average of fat intake.

RESULTS

We documented 1,049 incident cases of ischemic stroke over 663,041 person-years of follow-up. Women in the highest quintile of trans fat intake had a significantly higher incidence of ischemic stroke (HR, 1.39; 95% confidence interval [CI], 1.08-1.79; p-trend = 0.048) compared with women in the lowest quintile, while controlling for multiple covariates. The observed association was modified by aspirin use (p-interaction = 0.02). The HR was 1.66 (95% CI, 1.21-2.36; p-trend < 0.01) among baseline non-aspirin users (n = 67,288) and 0.95 (95% CI, 0.60-1.48; p-trend = 0.43) among aspirin users (n = 19,736). No significant associations were found between intakes of saturated, monounsaturated, or polyunsaturated fat and ischemic stroke or any ischemic stroke subtypes.

INTERPRETATION

In this large cohort of postmenopausal women, higher intake of trans fat was associated with incident ischemic stroke independent of major lifestyle/dietary factors. Aspirin use may attenuate the potential adverse effect of trans fat intake on ischemic stroke.

The puzzle of dietary fat intake and risk of ischemic stroke: a brief review of epidemiologic data

While coronary heart disease (CHD) and ischemic stroke share some major risk factors, limited epidemiologic data on dietary fats and vascular disease risk indicate that ischemic stroke is affected differently by these fatty acids than is CHD. The established associations between types of fat and CHD do not appear to apply to ischemic stroke. One explanatory hypothesis for the paradoxical observations is that arteriosclerosis in different types of cerebral arteries has different causal patterns. Fatty acids or blood lipids might not be as important as other factors, such as blood pressure, in the pathogenesis of a certain type of ischemic stroke. However, confirmatory data on the associations of fatty acids and subtype of ischemic stroke, including lacunar, atherosclerotic, and cardioembolic infarction, are lacking. The purpose of this review is to summarize the epidemiologic data on dietary fat and fatty acids in relation to ischemic stroke. Future investigations are needed to examine the effects of fatty acids on subtype of ischemic stroke and to clarify the possible differences of dietary fat in relation to ischemic stroke and CHD.

Plasma antioxidant activity and vascular dementia

Little is known about the role of antioxidant activity in the pathogenesis of stroke-associated neuronal damage and impairment following a stroke. Increased free radical formation together with reduced antioxidant defense may increase neuronal injury. A low concentration of antioxidants such as alpha-tocopherol may influence the development of post-stroke dementia. The aim of this study was to evaluate the level of alpha-tocopherol and susceptibility of LDL to oxidation in a group of patients with dementia in comparison to controls. In a group of 68 patients with dementia, according to DSM-IV criteria, 42 with vascular dementia (VaD), 26 with Alzheimer type of dementia (AD) and 46 age-matched persons, with no signs of cognitive disorders (control group), we measured lipids, alpha-tocopherol and the kinetics of LDL oxidation. The levels of triglycerides (TG) and low-density lipoprotein (LDL) were significantly lower in patients with VaD in comparison to AD patients, but the atherogenic index was similar in both groups. alpha-Tocopherol was significantly lower in patients with VaD in comparison to patients with AD and controls: 9.9, 12.6 and 12.6 ng/ml, respectively, p<0.0001. Susceptibility of LDL to oxidation, measured by duration of lag phase did not reveal statistically significant differences between the groups. In patients with VaD, low levels of plasma alpha-tocopherol were observed, which indicate a reduced antioxidant defense in these subjects.

Linoleic acid, other fatty acids, and the risk of stroke

BACKGROUND AND PURPOSE

The role of serum fatty acids as a risk factor for stroke and stroke subtypes is largely unknown.

METHODS

A prospective nested case-control study of Japanese 40 to 85 years of age was conducted through the use of frozen serum samples from 7450 participants in cardiovascular risk surveys collected from 1984 to 1989 for 1 community and 1989 to 1992 for the other 2 communities. By the end of 1998, we identified 197 incident strokes whose subtypes were confirmed by imaging studies. Three controls per case were selected by matching for sex, age, community, year of serum storage, and fasting status.

RESULTS

Compared with controls, total (n=197), hemorrhagic (n=75), and ischemic (n=122) strokes had similar proportions of n3 polyunsaturated fatty acids, lower proportions of linoleic and arachidonic acids, and higher proportions of saturated and monosaturated acids, determined by gas chromatography. The multivariate odds ratios associated with a 1-SD increase in linoleic acid (5%) after adjustment for hypertension, diabetes, serum total cholesterol, and other cardiovascular risk factors were 0.72 [95% confidence interval (CI), 0.59 to 0.89] for total stroke, 0.66 (95% CI, 0.49 to 0.88) for ischemic stroke, 0.63 (95% CI, 0.46 to 0.88) for lacunar infarction, and 0.81 (95% CI, 0.59 to 1.12) for hemorrhagic stroke. The respective odds ratios for saturated fatty acids (4%) were 1.13 (95% CI, 1.05 to 1.65), 1.35 (95% CI, 1.01 to 1.79), 1.44 (95% CI, 1.03 to 2.01), and 1.21 (95% CI, 0.82 to 1.80). Further adjustment for other fatty acids attenuated these relations, but the relation between linoleic acid and risk of ischemic stroke remained statistically significant.

CONCLUSIONS

A higher intake of linoleic acid may protect against ischemic stroke, possibly through potential mechanisms of decreased blood pressure, reduced platelet aggregation, and enhanced deformability of erythrocyte cells.

Dynamics of LDL oxidation in ischemic stroke patients

OBJECTIVE

Oxidative modification of human low density lipoprotein (LDL) plays an important role in the development of atherosclerosis. The aim of this study was to evaluate the oxidative modification of LDL in the group of patients with ischemic stroke.

MATERIAL AND METHODS

In the group of 43 patients 3 months after ischemic stroke and in the age and sex-matched control group, the kinetics of LDL oxidation and level of vitamin E were estimated. The susceptibility of LDL to oxidation was evaluated in isolated LDL exposed to in vitro oxidation. In 26 patients, after diet change, clinical and laboratory investigations were repeated 9 months later.

RESULTS

In the patient group, susceptibility of LDL to oxidation was enhanced, lag phase was significantly shorter in comparison with the control group. After a change in diet, significant elongation of the lag phase was observed.

CONCLUSION

Diet change improves LDL resistance to oxidation and may influence prognosis in stroke patients.

Serum lipids in young patients with ischaemic stroke: a case-control study

OBJECTIVES

The relation between serum lipids and ischaemic stroke remains controversial. Studies of lipid related risk factors in cerebrovascular disease have varied greatly in their findings and also in their definition of the cerebrovascular end points. Serum lipids are thought to interact with the pathogenesis of stroke through an atherosclerosis mechanism. Stroke in young patients have been shown to be related to non-atherosclerotic causes most of the time. The aim was to determine the serum lipid profile and the vascular risk factors for ischaemic stroke in a series of patients under 45 with an ischaemic stroke and to compare them with a series of controls of the same age.

METHODS

Ninety four consecutive patients with ischaemic stroke were compared with 111 controls of the same age recruited from a regional electoral list. Vascular risk factors were recorded and serum lipid profile was determined in all of them.

RESULTS

Multivariate analyses showed that low HDL cholesterol, male sex, smoking, hypertension, and oral contraceptives were risk factors for intracerebral arterial occlusion.

CONCLUSION

Low HDL cholesterol was the only serum lipid index to be associated to an increased risk of stroke in this population. Low HDL cholesterol must be considered in the care management of young patients regardless of the detectable presence of atherosclerosis.

Proteinuria is an independent risk factor for ischemic stroke in non-insulin-dependent diabetes mellitus

BACKGROUND AND PURPOSE

Proteinuria is an independent risk factor for cardiovascular disease in patients with NIDDM. The aim of this study was to assess the relationship between proteinuria and ischemic stroke in subjects with NIDDM, and to determine whether proteinuria is an independent risk factor for stroke.

METHODS

We performed a case-control study of 59 diabetic patients with first-ever ischemic stroke due to thrombotic arterial occlusion, who were considered cases, and 180 diabetic patients without stroke, matched by gender, age, and diabetes duration, as a control group. WHO criteria for verified definite or possible stroke were used to ascertain the diagnosis of stroke. For the purpose of this study proteinuria was defined as a 24-hour urinary protein excretion rate of >/=20 and <200 microg/min. Risk factors included were smoking, blood pressure, body mass index, serum total cholesterol, hyperglycemia, and proteinuria.

RESULTS

Subjects with stroke had higher proteinuria proportion and systolic and diastolic blood pressures. Both frequency of antihypertensive treatment and antihypertensive drugs used were similar among subjects with and without stroke. In multivariate logistic regression analysis, the ORs and 95% CIs for the variables identified as risk factors for stroke were as follows: systolic pressure (OR 3.10; 95% CI 3.01 to 4.21; P=0.03); diastolic pressure (OR 3.30; 95% CI 1.04 to 4.48; P<0.0001); fasting glucose >/=11.1 mmol (OR 1.82; 905% CI 1.4 to 3.8; P=0.04), HbA1c >/=9.5% (OR 1.7; 95% CI 1.3 to 5.1; P<0.01), and proteinuria (OR 3.23; 95% CI 1.06 to 4.36; P<0.0001).

CONCLUSIONS

Our case-control study gives evidence that proteinuria is an independent risk factor for ischemic stroke in patients with NIDDM.

Low serum cholesterol and the risk of cerebral haemorrhage

In addressing the potential for any hazards associated with lowering serum cholesterol, a recent meta-analysis by Law and colleagues (Br Med J 1994;308:373) concluded that that there was no evidence that a low or reduced serum cholesterol concentration increases mortality from any cause other than haemorrhagic stroke. In this review, the evidence for this unexpected association will be addressed, and possible mechanisms discussed. Overall implications of the phenomenon, particularly for the hypertensive patient, will be addressed in the context of the anticipated consequences of lipid-lowering therapy for all stroke, haemorrhagic and non-haemorrhagic, as well as ischaemic heart disease (IHD).

Predictors of stroke in middle-aged patients with non-insulin-dependent diabetes

BACKGROUND AND PURPOSE

The risk of stroke is known to be markedly elevated in patients with non-insulin-dependent diabetes mellitus (NIDDM), but the information on risk factors predicting stroke events in middle-aged NIDDM patients is limited. Therefore, we evaluated the significance of different cardiovascular risk factors with respect to the incidence of stroke in middle-aged NIDDM patients.

METHODS

Levels of cardiovascular risk factors were determined at baseline in 1059 NIDDM patients (581 men, 478 women) and 1373 nondiabetic control subjects (638 men, 735 women), aged from 45 to 64 years, in eastern and western Finland. These patients were followed up for 7 years with respect to stroke events.

RESULTS

Altogether, 34 NIDDM patients (13 men, 21 women) and 5 nondiabetic subjects (4 men, 1 woman) died from stroke, and 125 NIDDM patients (61 men, 64 women) and 30 (18 men, 12 women) nondiabetic subjects had a fatal or nonfatal stroke. The risk of stroke in NIDDM men was about threefold and in NIDDM women fivefold higher than that in corresponding nondiabetic subjects. Previous history of stroke increased the risk of a new stroke event by threefold. Patients with hyperglycemia (plasma glucose > 13.4 mmol/L) and high hemoglobin A1 (> 10.7%) had about a twofold higher risk of stroke than patients with better glycemic control. Low levels of high-density lipoprotein cholesterol (< 0.90 mmol/L), high levels of total triglyceride (> 2.30 mmol/L), and the presence of hypertension were associated with a twofold increase in the risk of stroke mortality or morbidity.

CONCLUSIONS

Our prospective population-based study gives evidence that previous history of stroke, hypertension, hyperglycemia, and dyslipidemia are strong predictors of stroke in middle-aged patients with NIDDM.

Serum fatty acids and the risk of stroke

BACKGROUND AND PURPOSE

To examine the relationship between serum fatty acids, which reflect dietary intake, and stroke, we conducted a nested case-control study of 96 men with incident stroke and 96 control subjects matched by age, clinical center, treatment group, and date of randomization who were enrolled in the Multiple Risk Factor Intervention Trial.

METHODS

After confirming the stability of the stored serum samples, we measured serum cholesterol ester and phospholipid fatty acid levels as the percentage of total fatty acids by gas-liquid chromatography and examined their association with incident stroke. Using stepwise conditional logistic regression that controlled for risk factors for stroke, we determined which fatty acids were independent correlates of stroke.

RESULTS

In univariate models, a standard deviation (SD) increase (1.37%) in phospholipid stearic acid (18:0) was associated with a 37% increase in the risk of stroke, whereas an SD increase (0.06%) in phospholipid omega-3 alpha-linolenic acid (18:3) was associated with a 28% decrease in the risk of stroke (all P < .05). Only alpha-linolenic acid in the cholesterol ester fraction was associated with the risk of stroke in multivariate models: an SD increase (0.13%) in the serum level of alpha-linolenic acid was associated with a 37% decrease in the risk of stroke (P < .05). Systolic blood pressure and cigarette smoking were also independently associated with stroke risk.

CONCLUSIONS

Our findings suggest that higher serum levels of the essential fatty acid alpha-linolenic acid are independently associated with a lower risk of stroke in middle-aged men at high risk for cardiovascular disease.

Platelet indices in patients with occlusive carotid artery disease

During the period 1965-1984 a total of 279 patients underwent carotid endarterectomy at the Tampere University Hospital; 160 of them were reexamined twenty-eight to two hundred nine months later to investigate whether there are any long-term differences in platelet properties according to the endpoint that led to operation. Platelet count, mean platelet volume (MPV), and plateletcrit were estimated and compared with the respective values for controls. Classified according to the indication for operation, patients with stroke had a significantly higher platelet count, 292 x 10(9)/L (SE 11), than patients with transient ischemic attack (TIA), 255 x 10(9)/L (SE 5, p < 0.01), or controls, 267 x 10(9)/L (SE 6, p < 0.05). Patients with stroke or TIA had a higher MPV than the controls. When the patients were grouped according to their physical condition at the time of the control examination, the largest platelets, 10.84 x 10(-15) L (SE 0.40), were found in the group of patients who felt well but who had a symptom or finding assumed to be due to a carotid disease.

The prevention of cardiovascular disease. Emphasis on secondary prevention

Atherosclerosis is a progressive disease affecting all major arteries. Clinical evidence of atherosclerosis increases the risk of subsequent morbid and mortal events fivefold to sevenfold over the next 5 to 10 years. The same risk factors contribute to the initial development of CVD events as to their recurrence. Both coronary and noncoronary events, such as stroke or PAD, reflect the severity of the underlying atherosclerotic process and strongly predict future excess CVD morbidity and mortality. Short-term and long-term survival depends on modifying the risk factors that contribute to CVD events. Although absolute proof of benefit for secondary prevention does not exist for all risk factors, the data from primary prevention trials and the secondary prevention trials that have been done argue strongly for aggressive intervention. Benefit has been demonstrated for smoking cessation, cholesterol reduction, and blood pressure control. Selected patients may benefit from additional medical, procedural, or surgical interventions to prolong life, such as beta-blocking agents, aspirin, or carotid endarterectomy. Many secondary prevention measures are a cost-effective way to reduce the substantial morbidity and mortality due to CVD. Contrary to primary prevention, even modest treatment effects from secondary prevention efforts can benefit large numbers of patients. Finally, secondary prevention may be more successful because patients with clinical evidence of CVD may be more highly motivated than their healthy counterparts to make and maintain lifestyle changes.

Serum cholestanol and plant sterol levels in relation to cholesterol metabolism in middle-aged men

Serum cholestanol was studied in relation to fecal cholestanol excretion and cholesterol metabolism in a random middle-aged population of 61 men. The serum concentrations of cholestanol ranged from 1.6 to 10.8 mumol/L and were positively correlated with those of serum total LDL and HDL cholesterol. In terms of millimole per mole of cholesterol, these correlations disappeared; inverse associations were found with VLDL cholesterol and triglyceride levels, the P/S ratio of dietary fat, and the amount of fecal plant sterols, but not with fecal cholestanol. The serum contents of cholestanol (1) were also closely positively associated with those of serum plant sterols (campesterol and sitosterol) and fractional cholesterol absorption, (2) were inversely related to the fecal excretion of neutral sterols and cholesterol synthesis which were measured either by the sterol balance technique or serum cholesterol precursor sterols (desmosterol and lathosterol), and (3) were unrelated to bile acid synthesis. Fecal cholestanol (mean = 12.5 mg/d) was (1) clearly higher than the dietary cholestanol intake (less than 2 mg/d), (2) unrelated to serum cholestanol, and (3) positively correlated with the intestinal cholesterol (dietary plus endogenous) flux as well as fecal plant sterols, neutral sterols, and bacterial products of cholesterol. The study emphasizes that, in normal men, high serum cholestanol levels reflect high efficiency of intestinal sterol absorption and low cholesterol synthesis. Thus, the changes in the serum contents of cholestanol are parallel with those of plant sterols and opposite to those of cholesterol precursor sterols.

Plasma and biliary cholestanol related to steroid metabolism in familial hypercholesterolemia patients with and without ileal exclusion

Plasma cholestanol is increased in cerebrotendinous xanthomatosis and in sitosterolemia with xanthomatosis. We measured plasma and biliary cholestanol in heterozygous familial hypercholesterolemia patients with (n = 10) and without (n = 12) ileal exclusion. In the unoperated patients plasma cholestanol concentration (12.9 mumol/l) and content (1.2 mmol/mol cholesterol) were slightly higher than in the nonhypercholesterolemic control subjects studied by us. Ileal exclusion had lowered plasma cholestanol concentration but only in proportion to the lowering of plasma cholesterol concentration, and plasma cholestanol content (mmol/mol cholesterol) was similar in the operated and unoperated subjects. Plasma and biliary cholestanol contents were positively associated. In the unoperated patients the fractional cholesterol absorption and plasma plant sterols, also reflecting sterol absorption, were positively correlated with plasma cholestanol content. Our study suggests, that plasma cholestanol is slightly elevated in familial hypercholesterolemia and that, in addition to plasma lipoprotein level, sterol absorption is important in the regulation of plasma cholestanol level. Ileal exclusion decreases plasma cholestanol in proportion to the decrement in the plasma cholesterol concentration.

Low platelet arachidonic acid in young patients with brain infarction

Fatty acid patterns of plasma and platelet lipids, platelet aggregation and thromboxane A2 (TxA2) production were studied in young patients (n = 12) with brain infarction and in healthy controls (n = 13). Platelet arachidonic acid content was significantly reduced in the stroke patients, but in vitro platelet aggregation was similar in the two groups. A low dose of acetosalicylic acid (ASA) (100 mg) suppressed thromboxane production and normalized the platelet arachidonic acid values. The low arachidonic acid in platelets is probably due to its increased consumption, indicating platelet activation in vivo.