Hikaru Nagasawa

Takotsubo Cardiomyopathy in Acute Ischemic Stroke

Takotsubo cardiomyopathy, which is characterized by transient left ventricular apical ballooning, is a known complication of subarachnoid hemorrhage. The aim of this study was to identify the clinical characteristics of acute ischemic stroke patients who experienced development of takotsubo cardiomyopathy.

The Role of G-Protein-Coupled Receptor Kinase 5 in Pathogenesis of Sporadic Parkinson's Disease

Sporadic Parkinsons disease (sPD) is a common neurodegenerative disorder, characterized by selective degeneration of dopaminergic neurons in the substantia nigra. Although the pathogenesis of the disease remains undetermined, phosphorylation of α-synuclein and its oligomer formation seem to play a key role. However, the protein kinase(s) involved in the phosphorylation in the pathogenesis of sPD has not been identified. Here, we found that G-protein-coupled receptor kinase 5 (GRK5) accumulated in Lewy bodies and colocalized with α-synuclein in the pathological structures of the brains of sPD patients. In cotransfected cells, GRK5 phosphorylated Ser-129 of α-synuclein at the plasma membrane and induced translocation of phosphorylated α-synuclein to the perikaryal area. GRK5-catalyzed phosphorylation also promoted the formation of soluble oligomers and aggregates of α-synuclein. Genetic association study revealed haplotypic association of the GRK5 gene with susceptibility to sPD. The haplotype contained two functional single-nucleotide polymorphisms, m22.1 and m24, in introns of the GRK5 gene, which bound to YY1 (Yin Yang-1) and CREB-1 (cAMP response element-binding protein 1), respectively, and increased transcriptional activity of the reporter gene. The results suggest that phosphorylation of α-synuclein by GRK5 plays a crucial role in the pathogenesis of sPD.

Microalbuminuria is a risk factor for cerebral small vessel disease in community-based elderly subjects

Microalbuminuria (MA) is known as a marker for generalized vascular dysfunction. It occurs most commonly in the setting of diabetes and hypertension; however, its association with cerebral small vessel disease (SVD) in community-based elderly remains to be clarified. In this cross-sectional analysis, we evaluated the association between MA and cerebral SVD in total 651 community-based elderly subjects. We assessed cardiovascular risk factors by interviews and physical examinations, including an evaluation of urinary albumin creatinine ratio (UACR). All subjects underwent brain magnetic resonance imaging (MRI) and carotid ultrasonography. As endothelial markers, the serum levels of thrombomodulin (TM) and a tissue-type plasminogen activator/ plasminogen activator inhibitor-1 complex were also studied. The mean TM and UACR were higher in subjects with lacunar infarcts or with moderate white matter hyperintensities (mWMH) on MRI than in those without them. Additionally, the prevalence of lacunar infarcts or mWMH was higher in the highest tertile of UACR level than in the lowest or middle tertile. Furthermore, in logistic regression analysis, the elevation of logarithmically transformed UACR (log UACR) was associated with the higher likelihood for total lacunar infarcts (odds ratio [OR], 1.85 per one log UACR increase), multiple lacunar infarcts (OR, 1.89 per one log UACR increase), and mWMH (OR, 2.15 per one log UACR increase). The present study revealed that levels of urinary albumin are associated with cerebral SVD, independently of traditional cerebrovascular risk factors, in community-based elderly.

Cerebral small vessel disease and chronic kidney disease (CKD): results of a cross-sectional study in community-based Japanese elderly.

Chronic kidney disease (CKD) is known as a risk factor for cardiovascular disease. In recent years, several experimental and epidemiological studies have suggested that CKD is associated with endothelial dysfunction; thereby, a CKD state may initiate both large and small vessel damage. The association between renal dysfunction and asymptomatic lacunar infarction was reported in a hospital-based study, whereas the relationship between cerebral small vessel disease (SVD)-related lesions and CKD could not be clarified in a community-based study. We performed a cross-sectional study to determine the relationship between silent cerebral SVD-related lesions and CKD in a total of 625 community-based Japanese elderly. In this study, subjects with lower estimated glomerular filtration rate levels tended to have more lacunar infarcts and higher grades of white matter lesions (WMLs). In addition, the mean grades of WMLs or the mean numbers of lacunar infarction in the subjects with albuminuria were greater than those in subjects without albuminuria. In the logistic regression analysis, the association between the presence of CKD and lacunar infarction or moderate WMLs (Fazekas grades 2 and 3) was statistically significant (odds ratio [OR]: 1.86 and 1.50, respectively). Furthermore, as we performed additional analysis, excluding the subjects with stage 2 hypertension (those with casual blood pressure >or=160/100 mm Hg) or diabetes, CKD remained to be an independent risk for cerebral SVD-related lesions. This is the first study showing the relationship between silent SVD-related brain lesions and the presence of CKD, independently of conventional cardiovascular risk factors, in community-based elderly.

Cystatin C as an index of cerebral small vessel disease: results of a cross-sectional study in community-based Japanese elderly

Background and purpose:  Recent studies have shown that kidney dysfunction is associated with cerebral small vessel disease (SVD). Although creatinine‐based estimating equations have been used as the standard measure for the evaluation of kidney function, the accuracy of these is limited in the elderly because of muscle mass decrease with aging. Cystatin C is a more useful measurement than creatinine‐based estimating equations for evaluating kidney function, however, the relationship amongst cystatin C, cognitive dysfunction, and cerebral SVD has not been fully examined in community‐based elderly.

Cerebral small vessel disease and C-reactive protein: results of a cross-sectional study in community-based Japanese elderly.

BACKGROUND AND PURPOSE Inflammatory processes are involved in the pathogenesis of atherosclerosis. Inflammation has been known as a risk factor for coronary heart disease, whereas inflammation as a risk for cerebrovascular disease is less well established. Whether inflammatory processes, excluded from their involvement in large-vessel disease, are implicated in the pathogenesis of cerebral small vessel disease remains unclear. We assessed whether higher C-reactive protein (CRP) levels were associated with an increased number of lacunar infarcts or severity of white matter lesions. METHODS AND RESULTS In a community-based group of Japanese elderly (n=689), CRP concentrations were measured using a highly sensitive assay. All participants underwent magnetic resonance imaging (MRI), and cerebral small vessel disease-related lesions (lacunar infarcts and white matter hyperintensity) were subsequently evaluated. Furthermore, carotid atherosclerosis was also assessed with ultrasonography. As the grades of white matter hyperintensity and the numbers of lacunes were considered small vessel disease-related lesions, we evaluated the relationships between CRP levels and small vessel disease-related brain lesions. Interestingly, the median CRP concentration of our participants was remarkably lower, being approximately one third or one quarter of the value of Western populations. Subjects with higher CRP levels tended to have more small vessel disease-related lesions; however, these associations were not seen after adjustment for cardiovascular risk factors and carotid atherosclerosis. CONCLUSIONS The relationship between CRP levels and small vessel disease-related lesions was not apparent in the community-based Japanese elderly. The impact of inflammation in the pathogenesis of small vessel disease-related brain lesions seems to be weak among the Japanese elderly.

A polymorphism of the aldehyde dehydrogenase 2 gene is a risk factor for multiple lacunar infarcts in Japanese men: the Takahata Study

The objective of the present study was to examine the association between a polymorphism of the aldehyde dehydrogenase 2 (ALDH2) gene and lacunar infarcts of the brain. We conducted a population‐based, cross‐sectional study on residents from two age groups (61‐ and 72‐year olds). A total of 376 subjects participated in the study, which included brain magnetic resonance image and genetic analysis of the ALDH2 gene. Of the 61‐ and 72‐year‐old subjects, 46.4% and 64.3%, respectively, had one or more lacunar infarcts. The average number of infarcts also increased from 2.0 to 2.8 in men and from 2.3 to 3.5 in women. No significant association between the ALDH2 genotype and the presence of lacunar infarction (≥1) was found. However, in subjects with lacunar infarction, the genotype of ALDH2 *1/*1 was associated with a larger number of the lesion [‘single’ versus ‘multiple’ odds ratio (OR) 3.73, 95%CI: 1.43–9.74] in men. The OR was comparable even after adjusting for alcohol consumption, tobacco habits, age, hypertension, hypercholesterolemia, and diabetes mellitus (DM) (OR 3.88; 95% CI: 1.10–13.66). In women, there was no significant association between the ALDH2 genotypes and lacunar infarcts. The present study revealed that the ALDH2 *1/*1 genotype was significantly associated with the prevalence of multiple lacunar infarcts in Japanese men.

Impact of Ambulatory Blood Pressure Variability on Cerebral Small Vessel Disease Progression and Cognitive Decline in Community-Based Elderly Japanese

BACKGROUND Recent epidemiological studies reported a relationship between 24-hour ambulatory blood pressure (ABP) variability and cardiovascular events. However, the impact of ABP variability on small vessel disease (SVD) progression or cognitive decline in the elderly has seldom been investigated in community-based longitudinal studies. METHODS Subjects (n = 210) underwent ABP monitoring, brain magnetic resonance imaging (MRI), and cognitive testing at baseline and 4 years later. ABP variability was quantified by the SD, weighted SD, coefficient of variation (CV), and average real variability (ARV). ABP variability parameters were divided into 2 groups by median values. RESULTS Multivariable logistic regression analyses showed that higher systolic CV, diastolic weighted SD, and diastolic CV were significant predictors of SVD progression (P = 0.02, 0.03, and 0.02, respectively). In subjects with SVD on the first MRI, higher systolic and diastolic ARV also predicted progression (P = 0.04 and 0.03, respectively). Higher quartiles of systolic weighted SD and CV had higher incidences of SVD progression (P trend = 0.03 and 0.03, respectively, Cochran-Armitage test), and higher quartiles of systolic ARV had higher incidences of SVD progression in subjects with SVD on the first MRI (P trend = 0.03). Higher systolic ARV was an independent predictor of cognitive decline (P < 0.01), and higher tertiles of systolic ARV had higher incidences of cognitive decline (P trend = 0.02). CONCLUSIONS This community-based longitudinal study found that increased ABP variability was associated with SVD progression, particularly in individuals with SVD at baseline. Higher systolic ARV predicted SVD progression and cognitive decline.

Familial normal pressure hydrocephalus (NPH) with an autosomal-dominant inheritance: A novel subgroup of NPH

Normal pressure hydrocephalus (NPH) has two clinical forms: secondary NPH and idiopathic NPH (iNPH). Most patients with NPH occur sporadically: until now, only two families have been reported to have sibling cases of NPH. We here report a large family with 4 patients with elderly-onset NPH in three generations. All of them had cognitive impairment, gait disturbance, and urinary problems, along with normal pressure of cerebrospinal fluid. Their brain MRI showed enlargement of the ventricles and a disproportional narrowing of the subarachnoid space and cortical sulci at the high convexity of the cerebrum, which are the features of iNPH on MRI. The family interview also disclosed additional 4 patients who were suspected as having NPH. The disease seems to be inherited in an autosomal-dominant fashion. No known causes of secondary NPH were found in any of the patients. This is the first report to show a large family with NPH patients in three generations, who had clinical and MRI features indistinguishable from iNPH. This seems to represent a novel subgroup of NPH, familial NPH.

Epidemic myalgia associated with human parechovirus type 3 infection among adults occurs during an outbreak among children: Findings from Yamagata, Japan, in 2011

BACKGROUND Based on our findings in Yamagata, Japan, in 2008, we reported that human parechovirus type 3 (HPeV3) could be associated with epidemic myalgia among adults, although HPeV3 is generally associated with infectious diseases in children. OBJECTIVES To clarify the relationship between community outbreaks among children and myalgia through the continued surveillance of HPeV3 infections. STUDY DESIGN In the summer season (June-August) of 2011, we collected 586 specimens from children with infectious diseases, and throat swabs, and stool and serum specimens from 5 patients with myalgia. We detected HPeV3 using virus isolation and reverse-transcription PCR, and carried out phylogenetic analysis. We also performed screening for HPeV3 using 309 stocked frozen specimens collected in 2008 for a comparison between 2008 and 2011 strains. RESULTS We detected HPeV3 in 59 children and isolated HPeV3 from all myalgia patients. Phylogenetic analysis indicated that the HPeV3 strains circulating in 2008 and 2011 could be clearly distinguished, apart from two strains. Further, we detected HPeV3 strains with identical nucleotide sequences from children and adults in 2008 and 2011, respectively. Two children belonging to one myalgia patient had upper respiratory infections prior to the onset of their fathers illness, and the HPeV3 isolates from these three patients had identical nucleotide sequences. CONCLUSIONS These findings suggest that HPeV3, circulating among children in the community, infects their household, including parents, a portion of whom may subsequently show symptoms of myalgia. Our observations in 2008 and 2011 strongly suggest that clinical consideration should be given to HPeV3 in children as well as in adults during summer seasons in which an HPeV3 outbreak occurs among the children in the community.