Keiji Kurita

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.

Lateral and Medial Medullary Infarction A Comparative Analysis of 214 Patients

Background and Purpose— No large-scale study has ever compared the clinical and radiological features of lateral medullary infarction (LMI) and medial medullary infarction (MMI). The aim of this study was to investigate them through the use of cooperatively collected cases. Methods— Medical information on all patients from 1996 to 2000 with medullary infarction (MI) proven by brain MR images at 35 stroke centers in the Tohoku district, Japan, was collected, and their clinical and radiological features were analyzed. Results— A total of 214 cases of MI were registered. They included 167 cases (78%) of LMI, 41 (19%) of MMI, and 6 (3%) of LMI plus MMI. The mean age of onset and the male-to-female ratio were 60.7 years and 2.7:1 in LMI and 65.0 years and 3.6:1 in MMI, respectively. The middle medulla was most frequently affected in LMI, and the upper medulla was most frequently affected in MMI. Dissection of the vertebral artery was observed in 29% of LMI and 21% of MMI. Prognosis, assessed by the Barthel Index, was favorable in both LMI and MMI. Diabetes mellitus was more frequently associated with MMI than with LMI. Conclusions— The present study surveyed a large number of MI cases and revealed that (1) the mean age of onset of MMI is higher than that of LMI, (2) the dissection of the vertebral artery is an important cause not only of LMI but also of MMI, and (3) diabetes mellitus is frequently associated with MMI.

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.

Marked increase in cerebrospinal fluid ubiquitin in Creutzfeldt-Jakob disease

We have established the radioimmunoassay for ubiquitin in the cerebrospinal fluid (CSF) and measured the ubiquitin concentration in CSF from 4 cases of neuropathologically verified Creutzfeldt-Jakob disease (CJD), 10 cases of multi-infarct dementia (MID), 7 cases of senile dementia of Alzheimer type (SDAT), and 18 controls. The normal values were determined to range from 7.3 to 21.0 ng/ml, 14.3 +/- 1.1 ng/ml in the mean +/- S.E.M. The CSF ubiquitin levels in the cases of MID and SDAT were 16.6 +/- 6.4 ng/ml and 21.3 +/- 6.1 ng/ml, respectively. In the cases of CJD, the CSF ubiquitin was markedly increased at the early and middle stages of the disease (230.6 ng/ml in Case 1, 107.6 ng/ml in Case 2, 212.5 ng/ml in Case 3, and 377.0 ng/ml in Case 4) and these gradually decreased as the disease progressed. The measurement of CSF ubiquitin seems useful to make an early diagnosis of CJD.

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.

Neuroprotective effect of oxidized galectin-1 in a transgenic mouse model of amyotrophic lateral sclerosis.

Abnormal accumulation of neurofilaments in motor neurons is a characteristic pathological finding in amyotrophic lateral sclerosis (ALS). Recently, we revealed that galectin-1, whose oxidized form has axonal regeneration-enhancing activity, accumulates in the neurofilamentous lesions in ALS. To investigate whether oxidized galectin-1 has a beneficial effect on ALS, oxidized recombinant human galectin-1 (rhGAL-1/ox) or physiological saline was injected into the left gastrocnemius muscle of the transgenic mice over-expressing a mutant copper/zinc superoxide dismutase (SOD1) with a substitution of histidine to arginine at position 46 (H46R SOD1). The H46R SOD1 transgenic mice, which represented a new animal model of familial ALS, were subsequently assessed for their disease onset, life span, duration of illness, and motor function. Furthermore, the number of remaining large anterior horn cells of spinal cords was also compared between the two groups. The results showed that administration of rhGAL-1/ox to the mice delayed the onset of their disease and prolonged the life of the mice and the duration of their illness. Motor function, as evaluated by a Rotarod performance, was improved in rhGAL-1/ox-treated mice. Significantly more anterior horn neurons of the lumbar and cervical cords were preserved in the mice injected with rhGAL-1/ox than in those injected with physiological saline. The study suggests that rhGAL-1/ox administration could be a new therapeutic strategy for ALS.

Regional differences in genetic subgroup frequency in hereditary cerebellar ataxia, and a morphometrical study of brain MR images in SCA1, MJD and SCA6.

Molecular genetic assessments of 69 individuals in 44 families with hereditary cerebellar ataxia (HCA) were made to determine the relative frequencies of subtypes of HCA in Yamagata, Japan. Fifteen families (34%) had SCA1, none had SCA2, nine (20%) had MJD, five (11%) had SCA6 and nine (20%) had DRPLA. These findings differ markedly from those in other regions of Japan and the rest of the world. A morphometrical study of the brain MR images also was made on 38 individuals with SCA1 (n = 14), MJD (n = 8) or SCA6 (n = 16). In SCA1, the ventral pons was atrophic in proportion to the amount of cerebellar atrophy. In MJD, both the pons and the cerebellum were atrophic, cerebellar atrophy being less pronounced than that in SCA1 and SCA6. While both the major and minor axes of the ventral pons were proportionally decreased in SCA1, the minor axis was more decreased than the major axis in MJD. In SCA6, a mild reduction in the ratio of the ventral pontine area to the posterior fossa area (Pv/PF) was observed as well as obvious cerebellar atrophy. These findings indicate that in MR images SCA1, MJD and SCA6 show different atrophic features of the cerebellum and brainstem.

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.