Autopsy study of cerebrovascular disease in Japanese men who lived in Hiroshima, Japan, and Honolulu, Hawaii

Progression of Carotid Intima-Media Thickness Partly Indicates the Prevention of Hypertension among Older Individuals in the General Population

Structural atherosclerosis, as evaluated by carotid intima-media thickness (CIMT), is reported to be positively associated with hypertension. However, angiogenesis, which plays an important role in the progression of structural atherosclerosis, prevents hypertension by reducing peripheral vascular resistance. These associations evoke a contradiction: characteristics associated with the progression of structural atherosclerosis, which is related to hypertension, might prevent hypertension. To clarify novel mechanisms underlying the association between structural atherosclerosis and hypertension, multifaceted analyses are necessary. We performed several epidemiological studies based on this concept. This study summarizes those epidemiological studies and adds some discussion. Studies focusing on circulating CD34-positive cells, single-nucleotide polymorphisms (SNPs) of vascular endothelial growth factor (VEGF), SNPs in BRACA1-associated protein (BRAP), platelets, human T-cell leukemia virus type 1 (HTLV-1), and SNPs in aldehyde dehydrogenase 2 (ALDH2) have shown that active endothelial repair, which leads to the progression of structural atherosclerosis, helps prevent hypertension. These associations indicate that the progression of structural atherosclerosis could act as a marker of angiogenesis, which reduces peripheral vascular resistance. In general, a positive association between structural atherosclerosis and hypertension has been reported. However, the progression of structural atherosclerosis could act as a marker of activity that prevents hypertension via reductions in peripheral vascular resistance.

Influence of height on endothelial maintenance activity: a narrative review

Recent studies have revealed an inverse association between height and cardiovascular disease. However, the background mechanism of this association has not yet been clarified. Height has also been reported to be positively associated with cancer. Therefore, well-known cardiovascular risk factors, such as increased oxidative stress and chronic inflammation, are not the best explanations for this inverse association because these risk factors are also related to cancer. However, impaired blood flow is the main pathological problem in cardiovascular disease, while glowing feeding vessels (angiogenesis) are the main characteristic of cancer pathologies. Therefore, endothelial maintenance activity, especially for the productivity of hematopoietic stem cells such as CD34-positive cells, could be associated with the height of an individual because this cell contributes not only to the progression of atherosclerosis but also to the development of angiogenesis. In addition, recent studies have also revealed a close connection between bone marrow activity and endothelial maintenance; bone marrow-derived hematopoietic stem cells contribute towards endothelial maintenance. Since the absolute volume of bone marrow is positively associated with height, height could influence endothelial maintenance activity. Based on these hypotheses, we performed several studies. The aim of this review is not only to discuss the association between height and bone marrow activity, but also to describe the potential mechanism underlying endothelial maintenance. In addition, this review also aims to explain some of the reasons that implicate hypertension as a major risk factor for stroke among the Japanese population. The review also aims to clarify the anthropological reasons behind the high risk of atherosclerosis progression in Japanese individuals with acquired genetic characteristics.

High Hematocrit Levels Are Associated with Risk of Cardiovascular Mortality among Middle-Aged Japanese Women: The Ibaraki Prefectural Health Study (IPHS)

In Japan, heart disease and cerebrovascular disease were the second and fourth leading cause of death, respectively in 2014. Hematocrit, the ratio of the red blood cells to the total volume of blood is known to play a role in cardiovascular diseases. However, the relationship between elevated hematocrit and the risk of cardiovascular disease based on sex has not been examined in Asian countries. We analyzed data from the Ibaraki Prefectural Health Study, a community-based large cohort study, which included 87,533 individuals, aged 40 to 79 years living in 38 municipalities of the Ibaraki Prefecture, who had completed an annual health checkup in 1993, and were followed until 2013. The hematocrit levels of the subjects were categorized into 5 quintiles (Q1-Q5), and hazard ratios for cause-specific mortality were calculated using the Cox proportional hazards regression models. Age and other cardiovascular risk factors were the covariates in the study. During the follow-up for a mean of 17.9 years, 1,207 deaths (615 men and 592 women) due to acute myocardial infarction (AMI) were reported in this population. The p values for the trend in the Q3-Q5 groups were 0.661 for men and 0.020 for women. Additionally, these values were significant in younger (40 to 59 years) women but not in older (60 to 79 years) women. This study is the first one to demonstrate an association between high hematocrit level and risk of AMI mortality in younger Japanese women, but not in men and older women.

High Dietary Saturated Fat is Associated with a Low Risk of Intracerebral Hemorrhage and Ischemic Stroke in Japanese but not in Non-Japanese: A Review and Meta-Analysis of Prospective Cohort Studies

AIM

The associations between dietary saturated fatty acids and the risks of stroke subtypes in cohort studies were examined by a meta-analysis of separate ethnic Japanese and non-Japanese cohorts, and causes of their difference were elucidated.

METHOD

Log hazard ratio (HR) with 95% confidence interval (CI) of the highest versus the lowest saturated fat intake from cohort studies were weighed by an inverse variance method to combine HRs.

RESULTS

Five studies of intracerebral hemorrhage and 11 studies/comparisons of ischemic stroke were selected. A meta-analysis of intracerebral hemorrhage excluding subarachnoid hemorrhage showed a strong inverse association in Japanese (n=3, HR=0.55, 95% CI 0.32-0.94) but not in non-Japanese (n=2, HR=0.98, 95% CI 0.62-1.53). A meta-analysis of ischemic stroke showed a mild inverse association in Japanese (n=4, HR=0.82, 95% CI 0.71-0.93) but not in non-Japanese (n=7, HR= 0.93, 95% CI 0.84-1.03). The effect size of saturated fat in reducing the risk of stroke in Japanese was stronger for intracerebral hemorrhage (45% reduction) than for ischemic stroke (18% reduction).

CONCLUSIONS

In Japanese but not in non-Japanese, a diet high in saturated fat is associated with a low risk of intracerebral hemorrhage and ischemic stroke. This may be due to differences in the range of intake of saturated fat, genetic susceptibility, incidence of lacunar infarction, and/or confounding factors such as dietary proteins. An intervention study targeting Japanese will be required to verify the causality.

Middle cerebral artery occlusive disease: the New England Medical Center Stroke Registry

To analyze the clinical features, vascular lesions, and infarct distribution in Asian and white patients with middle cerebral artery (MCA) territory ischemia, we studied age, sex, race, risk factors, angiographic, and neuroimaging findings among patients in the New England Medical Center Stroke Registry. We included patients with well-defined intrinsic occlusive lesions of the MCAs and patients with embolic MCA territory infarcts. Among 695 patients in the stroke registry, 89 (12.8%) qualified. They had 28 MCA intrinsic stenoses, 17 MCA embolic occlusions (cardiogenic or unknown origin), and 44 carotid artery (CA) stenoses or occlusions. MCA intrinsic disease patients were more often Asians and women, and more often had hypertension. Asians were older than whites. Coronary artery disease (27%), peripheral vascular disease (20.5%), and smoking (39%) were more common in CA disease patients. The most common site of MCA intrinsic stenosis (78%) and embolic occlusion (59%) was the mainstem MCA. Infarcts in patients with MCA intrinsic disease mostly involved the striatocapsular area (61%). Infarcts in patients with MCA embolic occlusion (75%) and CA disease (43%) most often involved the parietal lobe. In our hospital, most patients with MCA intrinsic disease are Asians and women and have hypertension and striatocapsular infarctions. Asian patients are usually older than white patients. The most common site of vascular lesions is the mainstem MCA.

A Review of Population-Based Retinal Studies of the Microvascular Contribution to Cerebrovascular Diseases

Studies of retinal signs, as non-invasively obtained markers of microvasculature, may help to assess the microvascular contribution to ischemic cardiovascular diseases, particularly those affecting the brain. Changes in the retinal arterioles are particularly pertinent to ischemia, and several studies show their associations with MRI-assessed cerebral lacunar infarcts and white matter changes. Data are too sparse to judge the contribution to cerebral atrophy or cognitive impairment. Confounding and imprecise measurements may cloud the results of this research. A paired comparison method is proposed for avoiding some of these issues.

Takayasu arteritis and giant cell arteritis: a spectrum within the same disease?

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) have been considered distinct disorders based on their clinical features, age of onset, and ethnic distribution. However, on closer examination, these disorders appear more similar than different. The histopathology of arterial lesions in these diseases may be indistinguishable. Imaging studies have revealed large vessel inflammation in at least 60% of patients with GCA. We questioned whether the distinctions between these diseases might in part be an artifact due to bias in gathering historical and physical data. We postulated that signs and symptoms of GCA and polymyalgia rheumatica occur in patients with TAK but have been under-reported as a result of this bias.We performed a retrospective review of 75 patients with TAK and 69 patients with GCA (per American College of Rheumatology criteria). Signs and symptoms attributable to disease within the year before and following diagnosis, treatment and interventional outcomes, and mortality were recorded using a standardized database. All cases were evaluated by a single physician, using identical history and physical examination forms for patients with both diseases.Patients were predominantly female (TAK 91%, GCA 82%) and white (TAK 88%, GCA 95%). New headache was a presenting symptom in 52% of TAK and in 70% of GCA patients. All TAK patients underwent vascular imaging studies and were demonstrated to have large vessel abnormalities. However, only a subset of patients with GCA (43/69, 62%) was similarly studied. Among this group, 73% of GCA patients had at least 1 arterial lesion identified. In both TAK and GCA, the most common sites of involvement were the aorta (TAK 77%, GCA 65%) and subclavian (TAK 65%, GCA 37%) arteries. Compared to patients with TAK, patients with GCA had a greater prevalence of jaw claudication (GCA 33%, TAK 5%), blurred vision (GCA 29%, TAK 8%), diplopia (GCA 9%, TAK 0%), and blindness (GCA 14%, TAK 0%).Symptoms, signs, and imaging abnormalities that are characteristic of GCA or TAK are often present, albeit in differing frequencies, in both disorders. These findings lend support to the hypothesis that these diseases may not be distinct entities, but represent skewed phenotypes within the spectrum of a single disorder. Differences in frequencies of manifestations may reflect a significant bias in how data are gathered for patients with each disease, as well as the influence of vascular and immunologic senescence.

Pattern of vascular dementia in India: study of clinical features, imaging, and vascular mechanisms from a hospital dementia registry

Vascular dementia (VaD) is heterogeneous in its clinical, imaging, and etiological characteristics. Although VaD is common in India, its pattern is not completely known. In a hospital-based cohort, we aimed to characterize VaD by its subtypes and study patterns of risk factors and clinical, and neuropsychological profiles. Vascular mechanisms, known to have racial and genetic variations were identified. NINDS-AIREN criteria were used to diagnose VaD. Patients were subtyped into subcortical, cortical, cortical-subcortical, and strategic infarct dementia. Vascular mechanisms were detected by vascular imaging, cardiac evaluation, and laboratory tests. In the 42 consecutive patients with VaD, subcortical dementia was the most common type (52.4%), followed by cortical-subcortical (26.2%), strategic infarcts in (14.3%), and cortical dementia (7.1%). Stroke (81%), hypertension (71.4%), and diabetes (35.7%) were important risk factors. Small artery disease was the underlying vascular mechanism in 42.9%; intracranial large artery disease, in 16.7%; extracranial disease, in 2.3%; cardioembolism, in 2.3%; multiple mechanisms, in 19%; and unknown, in 16.7%. Subtypes were similar in risk factor profile and neuropsychological features but differed in clinical characteristics and vascular mechanisms. Gait disorder (59.1% vs. 0%) and urinary symptoms (77.3% vs. 16.7%) were more common in subcortical dementia than in strategic infarct dementia (P < .05). Small artery disease was most common in subcortical dementia (72.7%). Intracranial large artery disease was associated with all subtypes. The pattern of VaD demonstrated in our study is a reflection of mechanisms of cerebrovascular disease in India. Outcome depends on underlying mechanisms and thus is likely to differ from that in other ethnic populations.

Factors associated with postoperative cognitive dysfunction in patients undergoing cardiac surgery

PURPOSE

Central nervous system complications continue to be major causes of morbidity and mortality after cardiac surgery. The purpose of this study was to identify the risk factors for postoperative cognitive dysfunction after coronary artery bypass graft (CABG) surgery.

METHODS

Eighty-eight patients scheduled for elective CABG were studied. After the induction of anesthesia, a fiberoptic oximetry oxygen saturation catheter was inserted into the right jugular bulb for the continuous monitoring of jugular venous oxygen hemoglobin saturation (SjvO(2)). The hemodynamic parameters and arterial and jugular venous blood gases were measured during cardiopulmonary bypass (CPB). All patients underwent a battery of neurological and neuropsychological tests one day before the operation and at 6 months after the operation.

RESULTS

The incidence of a cognitive decline at 6 months was 24/88 (27.3%). Greater age (P = 0.04), the presence of renal failure (P < 0.001), and diabetes mellitus (P < 0.001) were more frequent in the patients with postoperative cognitive dysfunction at 6 months after the operation than in patients without cognitive dysfunction. Age (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.0-1.7; P = 0.04), diabetes mellitus (OR, 1.8; 95% CI, 1.2-2.4; P < 0.01), and presence of renal failure (OR, 2.8; 95% CI, 2.4-4.3; P < 0.01) were associated with cognitive impairment at 6 months postoperatively. However, there was no relationship between the presence of atherosclerosis in the ascending aorta and postoperative cognitive dysfunction after CABG surgery.

CONCLUSIONS

A greater age, diabetes mellitus, and renal failure were found to be risk factors for development of cognitive impairment at 6 months after CABG with CPB.

Relationship between stroke and asymptomatic minute hemorrhages in hypertensive patients

Asymptomatic small hemorrhages were identified in hypertensive patients by T2*-weighted gradient echo magnetic resonance (MR) imaging to investigate the relationship between hypertensive intracerebral hemorrhage and asymptomatic minute hemorrhages. Forty-eight patients with hypertensive intracerebral hemorrhage or cerebral infarction with hypertension (these diseases were defined as stroke) were treated in National Defense Medical College from April 1998 to February 2000. All patients had no past history of stroke or head injury, underwent MR imaging within 6 months of the stroke attack, were aged from 40 to 80 years, and had no diagnosis of aneurysm, angioma, or moyamoya disease. Patients were divided into the infarction group and hemorrhage group. All foci over 2 mm in size appearing as hypointense on T2*-weighted MR imaging and unrelated to stroke areas were defined as minute hemorrhages. There were no significant differences between the two groups with respect to sex, age, and history of diabetes mellitus. The incidence of minute hemorrhages in the hemorrhage group (21/26) was greater than in the infarction group (9/22, p < 0.01). The incidence of minute hemorrhages in the basal ganglia (18/26) was greater in the hemorrhage group than in the infarction group (4/22, p < 0.001). Symptomatic intracerebral hemorrhage may be preceded by asymptomatic minute hemorrhage.

Latent cerebral artery stenoses on magnetic resonance angiography in a patient diagnosed as probable Alzheimer disease

A 65-year-old woman with hypertension developed slowly progressive memory disturbance and disorientation. She was diagnosed as having Alzheimer-type dementia according to clinical criteria. Later her cognitive deterioration was noted to fluctuate in parallel to her blood pressure. Magnetic resonance angiography and single photon emission computed tomography showed bilateral middle cerebral artery stenoses and middle cerebral artery watershed dominant hypoperfusion. It is postulated that the patient's cognitive disturbance may have originated from vascular lesions.

Racial differences in ischemic cerebrovascular disease: Clinical and magnetic resonance angiographic correlations of white and asian patients

OBJECTIVES

We explored racial differences in ischemic cerebrovascular disease.

METHODS

Clinical and magnetic resonance angiographic (MRA) features were compared in 21 white and 21 Asian patients with symptomatic ischemic cerebrovascular disease.

RESULTS

When all carotid artery sites were combined and compared, whites had more stenotic lesions of internal carotid artery origin, and Asians had more stenotic lesions of the middle cerebral artery (MCA) stem. In the vertebrobasilar territory, there were no significant differences in the distribution of extracranial and intracranial stenotic lesions between the two races. In symptomatic territories, the distribution of extracranial and intracranial stenosis were not significant differences for white and Asian patients. In asymptomatic territories, whites had a higher tendency for isolated extracranial stenosis, whereas Asians had an increased incidence of isolated intracranial stenosis. In the combined symptomatic and asymptomatic, carotid and vertebrobasilar territories, there was an increased incidence of extracranial carotid stenotic lesions in white patients and intracranial anterior circulation stenotic lesions in Asians. Demographic factors alone seemed to explain the difference.

CONCLUSIONS

Racial differences in the occurrence of extracranial and intracranial lesions raise the possibility of different pathophysiologic abnormalities.

Heterogeneity of vascular dementia: mechanisms and subgroups

Today, multiple, thromboembolically generated cerebral infarcts are regarded as the main pathogenetic pathway of vascular dementia (VAD), with multi-infarct dementia (MID) as its clinical counterpart. However, taking into account other vascular mechanisms that may influence the brain, such as vessel-wall damage (atherosclerosis, hyalinosis, amyloid angiopathy, or blood-brain barrier dysfunction), cerebrovascular insufficiency (disturbance of systemic circulation, perfusion vulnerability related to the vascular anatomy of the brain, or disturbance of autoregulation), and hyperviscosity, it is evident that MID is not the only VAD category. The diagnosis of MID ought to be reserved for the combination of progressive dementia associated with cerebral ischemic events and evidence of infarction that is mainly associated with the large cerebral arteries. Subcortical white-matter dementia characterized by frontosubcortical symptomatology, white-matter lesions, and small-vessel involvement with or without lacunes/infarcts--a combination of lacunar dementia and Binswanger's disease--appears to be another important VAD disease.

Stroke mortality in Miyagi, Japan

Hypertension is a major cause in stroke mortality in Japan but is not the sole factor. This research, based on geographical comparisons between two selected towns of contrasted stroke experience, implicates a poor indoor thermal environment as having an important role, especially by sudden changes in temperature between rooms elevating blood pressure. High dietary salt is also an important contributory cause of stroke and is already the target of a public education campaign to encourage a reduced intake.

Serum cholesterol, other risk factors, and cardiovascular disease in a Japanese cohort

The relationship of serum cholesterol and other risk factors to cardiovascular disease was investigated in a 16-year cohort of 16,711 residents of Hiroshima and Nagasaki. Examined in detail were the relationship of serum cholesterol, and the joint relationships of serum cholesterol, systolic blood pressure, diastolic blood pressure, and other risk factors to coronary heart disease (CHD), cerebral infarction (CI), and cerebral hemorrhage (CH). Baseline and biennially collected risk factor data were analyzed. The latter type of measurement permitted separate investigation of both the short-term and long-term effects of cholesterol measurements. In both types of analyses, both serum cholesterol and blood pressure showed strong associations with CHD incidence. In particular, there were strong associations with short-term and delayed CHD incidence. Furthermore, the association of cholesterol with short-term CHD incidence could not be explained by its association with delayed CHD incidence, or vice versa. Multivariate analyses that also included several other risk factors (smoking habits, clinical diagnosis of diabetes mellitus, left ventricular hypertrophy or strain on electrocardiogram, relative body weight, hematocrit, and proteinuria) for which data were available showed such risk factors to be of lesser, but generally non-negligible, importance in this population. In the case of CH and CI, serum cholesterol was found to be weakly or not at all related to incidence of either disease while blood pressure remained a strong correlate. For CI some suggestion of a statistical interaction between blood pressure and serum cholesterol was found. Discussed are implications for theories of disease pathogenesis for CHD, CI and CH.

Leukocyte counts and cerebrovascular disease

Elevated total leukocyte count in a biennial examination period is shown to be a significant (p = 0.001) predictor of cerebral infarction (CI) incidence in the subsequent 2 yr examination period, in a large Japanese cohort study. This association is not explainable on the basis of corresponding age, sex or blood pressure levels. The extent to which the association might be attributable to cigarette smoking habits could not be thoroughly examined with available data. Relative risks associated with a specific elevated leukocyte count may be larger among persons less than 65 yr of age than among older persons. When counts of specific leukocyte cell lines are considered a significant (p = 0.0006) role for neutrophil count emerges, while an additional predictive role for other leukocyte cell types could not be detected. In contrast, there is a suggestion that cerebral hemorrhage (CH) risk may be lower following an elevated leukocyte count. In particular, a negative association between lymphocyte count and CH incidence in the subsequent biennial examination cycle, is nearly significant (p = 0.07), in spite of a rather small number of CH cases in the sample.

Cerebrovascular and degenerative changes in the brain; a study of 233 Japanese 50 or more years of age

A neuropathologic study, chiefly cerebrovascular lesions and degenerative changes, was conducted on the brains of 233 subjects 50 years of age and over among 557 autopsy cases of RERF-ABCC Hiroshima in 1972-1974. There were some discrepancies between the principal clinical diagnosis and principal pathologic diagnosis in cerebrovascular disease. For cerebral hemorrhage, 8.6% were accounted for in the clinical diagnosis of the entire subjects while only 2.1% were accounted for in the pathologic diagnosis of the same subject. The degenerative changes in the central nervous system have been increasing with age and these changes were seen more in the females than in the males. Intracerebral arteriosclerosis of a moderate extension or more existed in 36.5% of the subjects and the frequency of this disease increased with age. the frequency of cerebral infarct increased with age. The location of the infarcts was most often seen in the basal ganglia and cortex of cerebrum, the size of the cortical infarct was within 0.5 cm in diameter and multiple. The vascular lesions or degenerative changes were seen in about 74% of the brains of 50 years and over.