Postural instability via a loss of intermittent control in elderly and patients with Parkinson's disease: A model-based and data-driven approach.

Postural instability is one of the major symptoms of Parkinson's disease. Here, we assimilated a model of intermittent delay feedback control during quiet standing into postural sway data from healthy young and elderly individuals as well as patients with Parkinson's disease to elucidate the possible mechanisms of instability. Specifically, we estimated the joint probability distribution of a set of parameters in the model using the Bayesian parameter inference such that the model with the inferred parameters can best-fit sway data for each individual. It was expected that the parameter values for three populations would distribute differently in the parameter space depending on their balance capability. Because the intermittent control model is parameterized by a parameter associated with the degree of intermittency in the control, it can represent not only the intermittent model but also the traditional continuous control model with no intermittency. We showed that the inferred parameter values for the three groups of individuals are classified into two major groups in the parameter space: one represents the intermittent control mostly for healthy people and patients with mild postural symptoms and the other the continuous control mostly for some elderly and patients with severe postural symptoms. The results of this study may be interpreted by postulating that increased postural instability in most Parkinson's patients and some elderly persons might be characterized as a dynamical disease.

Increased number of mitochondria in capillaries distributed in stroke-like lesions of two patients with MELAS.

We investigated two autopsy cases of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) using immunohistochemical staining with an anti-mitochondrial antibody against translocase of the outer membrane 20 (TOMM20). In case 1, the patient was a 42-year-old man with a disease duration of 53 days, and in case 2, the patient was a 62-year-old woman with a disease duration of 27 months. In both the cases autopsy revealed moderate atrophy of the cerebrum and cerebellum and multifocal necrotizing lesions, irrespective of the vascular territory. Case 1 showed multiple areas with total necrosis in the cortex, accompanied by increases in number of protoplasmic astrocytes and acidophilic neurons as well as axonal swelling, suggestive of acute or subacute stage stroke-like lesions (SLLs). In case 2, most of the SLLs displayed laminar spongy change in a rarefied cortex, and were considered to be at the chronic stage. In both the cases, capillary proliferation was noted within the SLLs, particularly in the acute phase. Endothelial cells of proliferating capillaries were strongly positive for TOMM20. In the cortex outside the SLLs, microvessels displayed only a fine granular immunoreactivity, as is seen in the controls. Although smooth muscle cells and endothelial cells in pial arteries and arterioles were also strongly positive for TOMM20, the territories of the affected pial arteries and arterioles did not correlate with the distribution of the SLLs. Although MELAS is characterized by recurrent stroke-like episodes (SLEs), the pathogenetic relationship between SLEs and mitochondrial angiopathy remains unknown. An aberrant increase of mitochondria in the capillary endothelial cells of SLLs may disturb endothelial function, thus playing a role in the formation or development of SLLs.

Temporal expression of growth factors triggered by epiregulin regulates inflammation development.

In this study, we investigated the relationship between several growth factors and inflammation development. Serum concentrations of epiregulin, amphiregulin, betacellulin, TGF-α, fibroblast growth factor 2, placental growth factor (PLGF), and tenascin C were increased in rheumatoid arthritis patients. Furthermore, local blockades of these growth factors suppressed the development of cytokine-induced arthritis in mice by inhibiting chemokine and IL-6 expressions. We found that epiregulin expression was early and followed by the induction of other growth factors at different sites of the joints. The same growth factors then regulated the expression of epiregulin at later time points of the arthritis. These growth factors were increased in patients suffering from multiple sclerosis (MS) and also played a role in the development of an MS model, experimental autoimmune encephalomyelitis. The results suggest that the temporal expression of growth factors is involved in the inflammation development seen in several diseases, including rheumatoid arthritis and MS. Therefore, various growth factor pathways might be good therapeutic targets for various inflammatory diseases.

An autopsy case of neuronal intermediate filament inclusion disease with regard to immunophenotypic and topographical analysis of the neuronal inclusions.

We report an autopsy case of neuronal intermediate filament inclusion disease (NIFID), in which pyramidal motor dysfunction preceded cognitive disturbance for 3 years from the onset. A 41-year-old Japanese man presented progressive spastic tetraparesis followed by cognitive impairment. His neurological symptoms gradually deteriorated and he died of pneumonia 16 years from the onset. His brain showed severe generalized atrophy with enlargement of ventricles. The microscopic examination revealed severe neuronal loss with gliosis and sponginess predominantly in the fronto-temporal cortices, caudate and putamen. Many hyaline conglomerate inclusions (HC) without immunoreactivity for 'fused in sarcoma' protein (FUS) and some granular and small round FUS-immunoreactive (FUS-ir) neuronal cytoplasmic inclusions (NCI) were observed in the remaining neurons. Some neurons with HC had small basophilic inclusions which showed positive FUS-ir, attached to HC in the cytoplasm. Otherwise, FUS-ir large compact inclusions (so-called Pick-like) were also observed but were scarce. In the cerebral cortex and the neostriatum, frequency of the inclusions was well correlated with neuronal loss. In the brainstem, neuronal loss was mild and FUS-ir inclusions dominated. In the subthalamic nucleus and red nucleus, there was no HC but there were many FUS-ir inclusions without neuronal loss. The above findings suggest that cytoplasmic mislocalization and aggregation of FUS appear at the early stage of the disease, and the FUS aggregate process may not be a direct precedent structure of HC.

Partial suppression of M1 microglia by Janus kinase 2 inhibitor does not protect against neurodegeneration in animal models of amyotrophic lateral sclerosis.

BACKGROUND: Accumulating evidence has shown that the inflammatory process participates in the pathogenesis of amyotrophic lateral sclerosis (ALS), suggesting a therapeutic potential of anti-inflammatory agents. Janus kinase 2 (JAK2), one of the key molecules in inflammation, transduces signals downstream of various inflammatory cytokines, and some Janus kinase inhibitors have already been clinically applied to the treatment of inflammatory diseases. However, the efficacy of JAK2 inhibitors in treatment of ALS remains to be demonstrated. In this study, we examined the role of JAK2 in ALS by administering a selective JAK2 inhibitor, R723, to an animal model of ALS (mSOD1G93A mice). FINDINGS: Orally administered R723 had sufficient access to spinal cord tissue of mSOD1G93A mice and significantly reduced the number of Ly6c positive blood monocytes, as well as the expression levels of IFN-γ and nitric oxide synthase 2, inducible (iNOS) in the spinal cord tissue. R723 treatment did not alter the expression levels of Il-1ß, Il-6, TNF, and NADPH oxidase 2 (NOX2), and suppressed the expression of Retnla, which is one of the markers of neuroprotective M2 microglia. As a result, R723 did not alter disease progression or survival of mSOD1G93A mice. CONCLUSIONS: JAK2 inhibitor was not effective against ALS symptoms in mSOD1G93A mice, irrespective of suppression in several inflammatory molecules. Simultaneous suppression of anti-inflammatory microglia with a failure to inhibit critical other inflammatory molecules might explain this result.

Elevation of Sema4A implicates Th cell skewing and the efficacy of IFN-ß therapy in multiple sclerosis.

Multiple sclerosis (MS) is a demyelinating autoimmune disease of the CNS and a leading cause of lasting neurologic disabilities in young adults. Although the precise mechanism remains incompletely understood, Ag presentation and subsequent myelin-reactive CD4(+) T cell activation/differentiation are essential for the pathogenesis of MS. Although semaphorins were initially identified as axon guidance cues during neural development, several semaphorins are crucially involved in various phases of immune responses. Sema4A is one of the membrane-type class IV semaphorins, which we originally identified from the cDNA library of dendritic cell (DC). Sema4A plays critical roles in T cell activation and Th1 differentiation during the course of experimental autoimmune encephalomyelitis, an animal model of MS; however, its pathological involvement in human MS has not been determined. In this study, we report that Sema4A is increased in the sera of patients with MS. The expression of Sema4A is increased on DCs in MS patients and shed from these cells in a metalloproteinase-dependent manner. DC-derived Sema4A is not only critical for Th1 but also for Th17 cell differentiation, and MS patients with high Sema4A levels exhibit Th17 skewing. Furthermore, patients with high Sema4A levels have more severe disabilities and are unresponsive to IFN-ß treatment. Taken together, our results suggest that Sema4A is involved in the pathogenesis of MS by promoting Th17 skewing.

Finger taps and constipation are closely related to symptoms of overactive bladder in male patients with Parkinson's disease.

OBJECTIVES: To assess which motor and non-motor symptoms are closely related to overactive bladder severity in male patients with Parkinson's disease. METHODS: A total of 160 male patients (mean age 71.4 ± 8.2 years) diagnosed with Parkinson's disease were included in the present study at Osaka University and affiliated hospitals. The severity of Parkinson's disease was classified as stage 3, 4 or 5 based on the Hoehn and Yahr staging system. Disease duration was 8.9 ± 5.1 years. Age, seven items from the Unified Parkinson's Disease Rating Scale motor section part III and three non-motor symptoms were assessed by multivariate analysis for their impact on the overactive bladder symptom score, a specific questionnaire for overactive bladder. RESULTS: Overactive bladder symptom score was significantly higher in the group with severe motor symptoms related to finger taps and gait than in the group with mild motor symptoms related to these two factors. Furthermore, overactive bladder symptom score of patients with erectile dysfunction and constipation was significantly higher than that in patients without these symptoms. Multivariate analysis identified only finger taps and constipation as factors independently associated with overactive bladder symptom score. CONCLUSIONS: Although a study on a larger scale is required to further assess the association of Parkinson's disease symptoms with overactive bladder symptom score, information on finger taps and severity of constipation should be obtained when assessing urological patients with Parkinson's disease.

Plexin-A1 and its interaction with DAP12 in immune responses and bone homeostasis.

Semaphorins and their receptors have diverse functions in axon guidance, organogenesis, vascularization and/or angiogenesis, oncogenesis and regulation of immune responses. The primary receptors for semaphorins are members of the plexin family. In particular, plexin-A1, together with ligand-binding neuropilins, transduces repulsive axon guidance signals for soluble class III semaphorins, whereas plexin-A1 has multiple functions in chick cardiogenesis as a receptor for the transmembrane semaphorin, Sema6D, independent of neuropilins. Additionally, plexin-A1 has been implicated in dendritic cell function in the immune system. However, the role of plexin-A1 in vivo, and the mechanisms underlying its pleiotropic functions, remain unclear. Here, we generated plexin-A1-deficient (plexin-A1(-/-)) mice and identified its important roles, not only in immune responses, but also in bone homeostasis. Furthermore, we show that plexin-A1 associates with the triggering receptor expressed on myeloid cells-2 (Trem-2), linking semaphorin-signalling to the immuno-receptor tyrosine-based activation motif (ITAM)-bearing adaptor protein, DAP12. These findings reveal an unexpected role for plexin-A1 and present a novel signalling mechanism for exerting the pleiotropic functions of semaphorins.

Neuroaxonal dystrophy in calcium-independent phospholipase A2ß deficiency results from insufficient remodeling and degeneration of mitochondrial and presynaptic membranes.

Infantile neuroaxonal dystrophy (INAD) is a fatal neurodegenerative disease characterized by the widespread presence of axonal swellings (spheroids) in the CNS and PNS and is caused by gene abnormality in PLA2G6 [calcium-independent phospholipase A(2)ß (iPLA(2)ß)], which is essential for remodeling of membrane phospholipids. To clarify the pathomechanism of INAD, we pathologically analyzed the spinal cords and sciatic nerves of iPLA(2)ß knock-out (KO) mice, a model of INAD. At 15 weeks (preclinical stage), periodic acid-Schiff (PAS)-positive granules were frequently observed in proximal axons and the perinuclear space of large neurons, and these were strongly positive for a marker of the mitochondrial outer membrane and negative for a marker of the inner membrane. By 100 weeks (late clinical stage), PAS-positive granules and spheroids had increased significantly in the distal parts of axons, and ultrastructural examination revealed that these granules were, in fact, mitochondria with degenerative inner membranes. Collapse of mitochondria in axons was accompanied by focal disappearance of the cytoskeleton. Partial membrane loss at axon terminals was also evident, accompanied by degenerative membranes in the same areas. Imaging mass spectrometry showed a prominent increase of docosahexaenoic acid-containing phosphatidylcholine in the gray matter, suggesting insufficient membrane remodeling in the presence of iPLA(2)ß deficiency. Prominent axonal degeneration in neuroaxonal dystrophy might be explained by the collapse of abnormal mitochondria after axonal transportation. Insufficient remodeling and degeneration of mitochondrial inner membranes and presynaptic membranes appear to be the cause of the neuroaxonal dystrophy in iPLA(2)ß-KO mice.

Roles of Sema4D-plexin-B1 interactions in the central nervous system for pathogenesis of experimental autoimmune encephalomyelitis.

Although semaphorins were originally identified as axonal guidance molecules during neuronal development, it is emerging that several semaphorins play crucial roles in various phases of immune responses. Sema4D/CD100, a class IV semaphorin, has been shown to be involved in the nervous and immune systems through its receptors plexin-B1 and CD72, respectively. However, the involvement of Sema4D in neuroinflammation still remains unclear. We found that Sema4D promoted inducible NO synthase expression by primary mouse microglia, the effects of which were abolished in plexin-B1-deficient but not in CD72-deficient microglia. In addition, during the development of experimental autoimmune encephalomyelitis (EAE), which was induced by immunization with myelin oligodendrocyte glycoprotein-derived peptides, we observed that the expression of Sema4D and plexin-B1 was induced in infiltrating mononuclear cells and microglia, respectively. Consistent with these expression profiles, when myelin oligodendrocyte glycoprotein-specific T cells derived from wild-type mice were adoptively transferred into plexin-B1-deficient mice or bone marrow chimera mice with plexin-B1-deficient CNS resident cells, the development of EAE was considerably attenuated. Furthermore, blocking Abs against Sema4D significantly inhibited neuroinflammation during EAE development. Collectively, our findings demonstrate the role of Sema4D-plexin-B1 interactions in the activation of microglia and provide their pathologic significance in neuroinflammation.

Chronic kidney disease and carotid atherosclerosis.

Chronic kidney disease is an independent risk factor for cardiovascular disease. The association between carotid intima-media thickness (IMT) and chronic kidney disease is controversial, however. In addition, whether renal dysfunction promotes vascular calcification in patients with chronic kidney disease is not clear. The study subjects were 1003 patients aged ≥50 years who underwent carotid ultrasonography in our hospital. Kidney function was evaluated based on the estimated glomerular filtration rate (eGFR) and the presence of proteinuria. Patients with end-stage renal failure were excluded. We measured the mean max-IMT (which indicates mean maximal wall thickness) at 12 carotid segments, and examined the characteristics of the maximal plaques by carotid ultrasonography. We evaluated the association between mean max-IMT and eGFR, and also evaluated the clinical factors associated with mean max-IMT and calcification of the maximal plaques. We found that eGFR was significantly correlated with mean max-IMT. Reduced eGFR, proteinuria, age, male sex, cardiovascular disease, hypertension, diabetes, and smoking were independently associated with mean max-IMT in multiple regression analysis. Kidney function was not associated with calcified plaque. Kidney dysfunction was associated with carotid atherosclerosis in patients with mild or moderate chronic kidney disease.

A mutation in a rare type of intron in a sodium-channel gene results in aberrant splicing and causes myotonia.

Many mutations in the skeletal-muscle sodium-channel gene SCN4A have been associated with myotonia and/or periodic paralysis, but so far all of these mutations are located in exons. We found a patient with myotonia caused by a deletion/insertion located in intron 21 of SCN4A, which is an AT-AC type II intron. This is a rare class of introns that, despite having AT-AC boundaries, are spliced by the major or U2-type spliceosome. The patient's skeletal muscle expressed aberrantly spliced SCN4A mRNA isoforms generated by activation of cryptic splice sites. In addition, genetic suppression experiments using an SCN4A minigene showed that the mutant 5' splice site has impaired binding to the U1 and U6 snRNPs, which are the cognate factors for recognition of U2-type 5' splice sites. One of the aberrantly spliced isoforms encodes a channel with a 35-amino acid insertion in the cytoplasmic loop between domains III and IV of Nav1.4. The mutant channel exhibited a marked disruption of fast inactivation, and a simulation in silico showed that the channel defect is consistent with the patient's myotonic symptoms. This is the first report of a disease-associated mutation in an AT-AC type II intron, and also the first intronic mutation in a voltage-gated ion channel gene showing a gain-of-function defect.

Deleterious effects of lymphocytes at the early stage of neurodegeneration in an animal model of amyotrophic lateral sclerosis.

BACKGROUND: Non-neuronal cells, such as microglia and lymphocytes, are thought to be involved in the pathogenesis of amyotrophic lateral sclerosis (ALS). Previous studies have demonstrated neuroprotective effects of lymphocytes at the end stage of ALS, partly through induction of alternatively activated microglia (M2 microglia), which are neuroprotective. In this study, we investigated the role of lymphocytes in the early stage of the disease using an animal model of inherited ALS. METHODS: We established a transgenic mouse line overexpressing the familial ALS-associated G93A-SOD1 mutation (harboring a single amino acid substitution of glycine to alanine at codon 93) with depletion of the Rag2 gene (mSOD1/RAG2-/- mice), an animal model of inherited ALS lacking mature lymphocytes. Body weights, clinical scores and motor performance (hanging wire test) of mSOD1/RAG2-/- mice were compared to those of mutant human SOD1 transgenic mice (mSOD1/RAG2+/+ mice). Activation of glial cells in the spinal cords of these mice was determined immunohistochemically, and the expression of mRNA for various inflammatory and anti-inflammatory molecules was evaluated. RESULTS: Clinical onset in mSOD1/RAG2-/- mice was significantly delayed, and the number of lectin-positive cells in spinal cord was increased at the early stage of disease when compared to mSOD1/RAG2+/+ mice. Quantitative RT-PCR confirmed that mRNA for Ym1, an M2 microglial-related molecule, was significantly increased in mSOD1/RAG2-/- mouse spinal cords at the early disease stage. CONCLUSIONS: Compared with mSOD1/RAG2+/+ mice, mSOD1/RAG2-/- mice displayed delayed onset and increased M2 microglial activation at the early stage of disease. Thus, lymphocytes at the early pathological phase of ALS display a deleterious effect via inhibition of M2 microglial activation.

Hypertension impairs leptomeningeal collateral growth after common carotid artery occlusion: restoration by antihypertensive treatment.

Chronic mild hypoperfusion has been shown to enlarge pial collateral vessels in normal mouse brains. The purpose of this study was to clarify the effect of hypertension on pial collateral vessel development after chronic hypoperfusion using spontaneously hypertensive rats (SHR). In normotensive rats, unilateral common carotid artery (CCA) occlusion enlarged leptomeningeal collateral vessels. CCA occlusion also preserved residual cerebral blood flow (CBF) and attenuated infarct size after middle cerebral artery (MCA) occlusion 14 days later. In contrast, in SHR, CCA occlusion neither enlarged the leptomeningeal anastomosis nor showed protective effects after MCA occlusion. However, decreasing blood pressure using an angiotensin II AT1 receptor blocker restored the beneficial effect of CCA occlusion on collateral growth as well as on residual CBF and infarct size after MCA occlusion. Adaptive responses in CBF autoregulation curves observed 14 days after CCA occlusion in normotensive rats were impaired in untreated SHR, but were restored after antihypertensive treatment. In conclusion, SHR have impaired leptomeningeal collateral growth after CCA occlusion, but antihypertensive treatment restores the beneficial effect of CCA occlusion on collateral circulation.

[A longitudinal cause-of-death analysis of patients with Duchenne muscular dystrophy].

Mechanical ventilation (MV) and cardiac protective therapy have improved the prognosis and quality of life of patients with Duchenne muscular dystrophy (DMD). To understand how these therapies have changed prognosis, we performed a cause-of-death analysis in DMD patients. Mean age at death before initiation of MV (January 1977-July 1984) was 18.9±4.1 years. After the introduction of MV, from August 1984 to December 1993 (1(st) term), it was 20.0±4.5 years, from January 1994 to December 2003 (2(nd) term), it was 25.2±4.6 years, and from January 2004 to December 2010 (3(rd) term), it was 31.1±5.4 years. Almost half of all deaths before MV were due to respiratory failure (RF). Because MV was performed by a tracheostomy in the initial stage, some patients were reluctant to use it, and as a result, RF accounted for 43% of deaths in the 1(st) term. Over time, patients started to accept non-invasive ventilation and home mechanical ventilation, which became available in the 1990s. Consequently, no DMD patients have died from RF since 2000. Respiratory physiotherapy and risk management became important tools, because many patients undergo decades of respiratory managements at home. Cardiac treatments for patients with DMD consisted mainly of diuretics and digitalis in the 1(st) term, angiotensin-converting enzyme inhibitors (ACEI) in the 2(nd) term, and a combination of ACEIs and beta blockers in the 3(rd) term. Compared to the 2(nd) term, the ratios of severe cardiac dysfunction (fractional shortening <10%, left ventricle diastolic dimension >75mm, plasma brain natriuretic peptide >1,000pg/ml) were reduced in the 3(rd) term. In the 3(rd) term, 14% of patients died from renal failure nevertheless their cardiac indices remained mildly abnormal or normal. We should pay enough attention for cardio-renal association.

[A survey of cardiologists, diabetologists, gynecologists and ophthalmologists practicing in Osaka on the medical consultation behaviors of myotonic dystrophy patients].

An anonymous postal survey of cardiologists, diabetologists, gynecologists, and ophthalmologists in Osaka was performed to assess the medical care-seeking behaviors of and problems associated with the medical management of patients with myotonic dystrophy (DM). The questionnaires were sent to 927 cardiologists, 357 diabetologists, 882 gynecologists, and 915 ophthalmologists. Of these, 172 cardiologists, 85 diabetologists, 220 gynecologists, and 154 ophthalmologists responded. More than 30% of responders had provided care to DM patients, and approximately 10% had experience diagnosing DM patients. These facts suggest that DM patients receive medical care from various specialists due to complications involving multiple systems and some of them visit other specialists prior to neurologists. Some patients were diagnosed after perinatal or perioperative difficulties. Therefore, it seems important to improve the ability of physicians to identify DM patients. Because specialists with experience diagnosing DM paid more attention to the characteristic features of DM, such as grip myotonia and hatchet face, a simple screening test may be useful for detecting DM. Some responders pointed out the negative attitude of DM patients toward medical care and the lack of neurologists for consultation as problems in the medical management of DM patients. Cooperation among neurologists and other specialists and education of DM patients are important to improve the medical management of DM patients.

Reduced tongue pressure against the hard palate on the paralyzed side during swallowing predicts Dysphagia in patients with acute stroke.

BACKGROUND AND PURPOSE: Dysphagia is important for prognosis in patients with stroke because this condition can cause aspiration pneumonia or nutritional deficits. The present study investigated the relationship between tongue motor deficits and dysphagia in patients with acute stroke. METHODS: Maximal tongue pressure on the hard palate when swallowing 5 mL of water was measured using a T-shaped sensor sheet with 5 measuring points in 33 dysphagic and 31 nondysphagic patients with acute stroke. Maximum tongue pressures at each measuring point were compared between dysphagic and nondysphagic groups and between paralyzed and nonparalyzed sides. RESULTS: Tongue pressure at each measuring point was significantly smaller in dysphagic patients than in nondysphagic patients with the largest significant difference on the paralyzed side. The magnitude of tongue pressure to predict dysphagia was calculated as 4.6 kPa on the paralyzed side, offering 71.4% sensitivity and 72.3% specificity. CONCLUSIONS: Reduced tongue pressure on the paralyzed side may predict dysphagia in patients with acute stroke.

Anti-aquaporin-4 antibody induces astrocytic cytotoxicity in the absence of CNS antigen-specific T cells.

Neuromyelitis optica (NMO) is an inflammatory demyelinating disease of the central nervous system (CNS). Anti-aquaporin-4 antibody (AQP4-Ab) is a highly specific serum autoantibody that is detected in patients with NMO. Several lines of evidence indicate that AQP4-Ab not only serves as a disease marker but also plays a pivotal role in the pathogenesis of NMO. Although the pathogenicity of AQP4-Ab in vivo has recently been demonstrated, the presence of CNS antigen-specific T cells is recognized as a prerequisite for the antibody to exert pathogenic effects. Thus, it remains unclear whether AQP4-Ab is the primary cause of the disease or a disease-modifying factor in NMO. Here we report that pre-treatment with complete Freund's adjuvant (CFA) alone is sufficient for AQP4-Ab to induce astrocytic damage in vivo. Our results show the primary pathogenic role of AQP4-Ab in the absence of CNS antigen-specific T cells, and suggest that danger signals provided by nonspecific inflammation can be a trigger for those who harbor the autoantibody to develop NMO.

An angiotensin II type 1 receptor blocker can preserve endothelial function and attenuate brain ischemic damage in spontaneously hypertensive rats.

Hypertension reduces endothelial nitric oxide synthase (eNOS) expression and leads to endothelial dysfunction. However, few studies have demonstrated the influences of hypertension on eNOS function in the cerebral cortex. The present study investigates the influences of hypertension on endothelial function in the cerebral cortex and the protective effects of antihypertensive agents against brain ischemia through the preservation of endothelial function. Five- and ten-week-old male Wistar rats and spontaneously hypertensive rats (SHR) were used for experiments. Five-week-old SHR received olmesartan, hydralazine, or vehicle for 5 weeks in drinking water. eNOS activation in the cerebral cortex was evaluated by analyzing levels of total and Ser(1177)-phosphorylated eNOS protein by Western blot. Blood pressure of 10-week-old SHR without treatment was clearly high, and the ratio of phospho-eNOS/total eNOS protein was significantly low. Five-week treatment with olmesartan or hydralazine suppressed the elevation of blood pressure and the reduction of phosphorylated eNOS-Ser(1177) in SHR, and olmesartan was more effective in maintaining phosphorylation of eNOS-Ser(1177) than hydralazine. To assess the contribution of eNOS to maintaining cerebral blood flow (CBF), we monitored CBF by laser-Doppler flowmetry after L-N(5)-(1-iminoethyl)ornithine (L-NIO) infusion. CBF response to L-NIO was preserved in olmesartan-treated SHR but not in hydralazine-treated SHR. Furthermore, infarct volume 48 hr after transient focal brain ischemia in olmesartan-treated SHR was significantly reduced compared with vehicle-treated SHR. These findings indicate that chronic prehypertensive treatment with olmesartan could attenuate brain ischemic injury through the maintenance of endothelial function in the cerebral cortex in SHR.

Increased expression and activation of cytosolic phospholipase A2 in the spinal cord of patients with sporadic amyotrophic lateral sclerosis.

Compelling evidence identifies a link between cytotoxic effects of cytosolic phospholipase A2 (cPLA2) activity and neuron death in cell cultures. cPLA2 catalyzes the hydrolysis of membrane phospholipids to produce and release arachidonate, leading to plasma membrane injury, inflammatory response and subsequent cell death. To assess a role for cPLA2 in the pathomechanism of amyotrophic lateral sclerosis (ALS), we performed immunohistochemical, immunoblot, and densitometric analyses of cPLA2 and its active form phosphorylated at S505 (p-cPLA2) on spinal cords obtained at autopsy from ten sporadic ALS patients and ten age-matched controls. On sections, immunoreactivities for cPLA2 and p-cPLA2 were distinct and localized in almost all of the motor neurons, reactive astrocytes, and activated microglia in the ALS cases, while immunoreactivities were only weak or not at all observed in neurons and glia in the control cases. On immunoblots, both the cPLA2/ß-actin density ratio and the p-cPLA2/cPLA2 density ratio were significantly increased in the ALS group compared to the control group. There was no significant link between the densitometric data and the clinical phenotypes, age at death or disease duration of the ALS patients. These results provide in vivo evidence for increased expression and activation of cPLA2 in motor neurons, reactive astrocytes, and activated microglia in ALS, suggesting occurrence of arachidonate cascade-induced motor neuron death via cell-autonomous and/or non-cell-autonomous mechanisms.