Long-term effect of telmisartan on Alzheimer's amyloid genesis in SHR-SR after tMCAO.

Telmisartan is expected to reduce not only the level of blood pressure but also neuroinflammation and neurotoxicity via pleiotrophic effects as a metabo-sartan. We examined the effects of telmisartan on Alzheimer's disease (AD) pathology in spontaneously hypertensive rat stroke resistant (SHR-SR) after transient middle cerebral artery occlusion (tMCAO) by giving either telmisartan at 0 (vehicle), 0.3 mg/kg/day (low dose, with no reduction of blood pressure), or 3 mg/kg/day (high dose, with a significant reduction of blood pressure) p.o. from 3 months (M) of age, and performed immunohistological analysis at 6, 12, and 18 M of age. The numbers of amyloid ß (Aß)-positive neurons in the cerebral cortex and hippocampus and senile plaque (SP) in the ipsilateral cerebral cortex progressively increased with age until 18 M in the SHR-SR after tMCAO. On the other hand, low-dose telmisartan significantly reduced the number of Aß-positive neuron as well as SP at 6, 12, and 18 M. High-dose telmisartan showed further reductions of the above AD pathology. The present study suggests that telmisartan reduced both intracellular Aß and extracellular SP accumulations after tMCAO in SHR-SR, with a further improvement by combined BP lowering. Such a strong effect of telmisartan could provide a preventative approach for AD in post-stroke patients with hypertension.

Telmisartan reduces progressive accumulation of cellular amyloid beta and phosphorylated tau with inflammatory responses in aged spontaneously hypertensive stroke resistant rat.

BACKGROUND: In addition to reducing the level of blood pressure (BP), telmisartan was expected to show the long-term neuroprotective effects preventing accumulation of cellular amyloid beta peptide (Aß) and phosphorylated tau (pτ) by ameliorating neuroinflammation. METHODS: We examined effects of telmisartan on cellular Aß and pτ with inflammatory responses in the brain of a spontaneously hypertensive stroke resistant (SHR-SR) rat by giving either telmisartan at 0 (vehicle), .3 mg/kg/day or 3 mg/kg/day, orally, from 3 months of age and performed immunohistologic analysis at 6, 12, and 18 months. Compared with normotensive Wistar rats, numbers of Aß- and pτ-positive neurons in the cerebral cortex progressively increased with age until 18 months in the SHR-SR rats, as did the numbers of ionized calcium-binding adapter molecule 1 (Iba-1)-positive microglia, tumor necrosis factor alpha (TNF-α)-positive neurons, and monocyte chemotactic protein 1 (MCP-1)-positive neurons. RESULTS: Low-dose telmisartan significantly decreased the numbers of Aß- and pτ-positive neuron as well as the numbers of TNF-α-positive neurons, Iba-1-positive microglia, and MCP-1-positive neurons at 6, 12, and 18 months. High-dose telmisartan reduced BP and showed a further reduction of cellular Aß and pτ. CONCLUSIONS: The present study suggests that accumulation of cellular Aß and pτ and the inflammatory responses were decreased via improving metabolic syndrome with low-dose telmisartan and improving both metabolic syndrome and hypertension with high-dose telmisartan.

Anti-inflammatory effect of amlodipine plus atorvastatin treatment on carotid atherosclerosis in zucker metabolic syndrome rats.

To investigate the effects of amlodipine in combination with atorvastatin on carotid atherosclerotic changes in metabolic syndrome, 8-week-old Zucker fatty rats were treated with vehicle, amlodipine, atorvastatin, or amlodipine in combination with atorvastatin for 28 days. Histological studies of common carotid arteries showed that lipid deposition determined by Sudan III staining was significantly reduced in rats treated with amlodipine or atorvastatin alone and was further reduced by amlodipine in combination with atorvastatin. Immunohistochemical studies of the pro-inflammatory cytokine tumor necrosis factor (TNF)-α, the arterial calcification initiator bone morphogenetic protein (BMP) 2, the angiogenic factor Notch1, and the smooth muscle cell marker α-smooth muscle actin (SMA) showed that the high expression of all four protein in vehicle-treated rats was greatly decreased by amlodipine, atorvastatin, or amlodipine in combination with atorvastatin, in ascending order. Double immunostaining showed marked colocalization of TNF-α with bone morphogenetic protein 2 and Notch1 with α-SMA in the vehicle group, which was greatly reduced by amlodipine plus atorvastatin. These data suggest that combination therapy may be more effective in preventing atherosclerotic processes and subsequent carotid vascular events than administrating amlodipine or atorvastatin alone in metabolic syndrome.

[Future neuroprotective strategies in the post-thrombolysis era--neurovascular unit protection and vascular endothelial protection].

From an appearance of recombinant tissue plasminogen activator (rt-PA) in the clinical therapy on 2005 in Japan, the therapeutic strategy of ischemic stroke therapy is now changing dramatically. Many experimental data from animal stroke and clinical trials of neuroprotective agents failed to clinical useful therapeutic strategy. A free radical scavenger, edaravone is the first clinical drug for neuroprotection in the world which has been used in almost all ischemic stroke patients in Japan from 2001. Now, it is especially useful in thrombolytic therapy with rtPA, whereas we still need the newly more effective neuroprotective drugs which can be applied to many ischemic stroke patients. Therefore, we review and describe the future neuroprotective strategies in the post-thrombolysis era.

Gene and stem cell therapy in ischemic stroke.

Possible strategies for treating ischemic stroke include neuroprotection (preventing injured neurons from undergoing apoptosis in the acute phase of cerebral ischemia) and stem cell therapy (the repair of disrupted neuronal networks with newly born neurons in the chronic phase of cerebral ischemia). First, we estimated the neuroprotective effect of glial cell line-derived neurotrophic factor (GDNF) by administration of GFNF protein. GDNF protein showed a direct protective effect against ischemic brain damage. Pretreatment of animals with adenoviral vector containing GDNF gene (Ad-GDNF) 24 h before the subsequent transient middle cerebral artery occlusion (MCAO) effectively reduced infarcted volume. Secondly, we studied the neuroprotective effect of a calcium channel blocker, azelnidipine, or a by-product of heme degradation, biliverdin. Both azelnidipine and biliverdin had a neuroprotective effect in the ischemic brain through their antioxidative property. Lastly, we developed a restorative stroke therapy with a bioaffinitive scaffold, which is able to provide an appropriate platform for newly born neurons. In the future, we will combine these strategies to develop more effective therapies for treatment of strokes.

Changes of Nogo-A and receptor NgR in the lumbar spinal cord of ALS model mice.

Detailed assessment of Nogo-A and its receptor NgR in the spinal cord of amyotrophic lateral sclerosis (ALS) models or patients has not been reported previously, and we examined the expression and distribution patterns of Nogo-A and NgR in an ALS mouse model to determine whether these molecules play a role in this disease. As compared with wild-type (WT) mice, transgenic (Tg) mice showed that the expression levels of Nogo-A transiently increased in motor neurons at an age of 10 weeks old (W), while it progressively decreased from 15 to 18 W. NgR expression in motor neurons of the Tg mice increased at 10 W, then progressively decreased from 15 to 18 W. In contrast, there was no significant change in the dorsal lumbar cord or the cerebellum of Tg mice throughout the progression of ALS. This study suggests that the function of Nogo-A may alter under certain conditions and locations, and thus transient overexpression of Nogo-A and NgR in motor neurons of this ALS mouse model at 10 W may represent a survival reaction of these cells under stressful conditions.

Dissociation and protection of the neurovascular unit after thrombolysis and reperfusion in ischemic rat brain.

In the ischemic brain, reperfusion with tissue plasminogen activator (tPA) sometimes causes catastrophic hemorrhagic transformation (HT); however, the mechanism remains elusive. Here, we show that the basement membrane, and not the endothelial cells, is vulnerable to ischemic/reperfusion injury with tPA treatment. We treated a spontaneously hypertensive rat model of middle cerebral artery occlusion (MCAO) with vehicle alone, tPA alone, or a free radical scavenger, edaravone, plus tPA. Light and electron microscopic analyses of each microvascular component revealed that the basement membrane disintegrated and became detached from the astrocyte endfeet in tPA-treated animals that showed HT. On the other hand, edaravone prevented the dissociation of the neurovascular unit, dramatically decreased the HT, and improved the neurologic score and survival rate of the tPA-treated rats. These results suggest that the basement membrane that underlies the endothelial cells is a key structure for maintaining the integrity of the neurovascular unit, and a free-radical scavenger can be a viable agent for inhibiting tPA-induced HT.

Progressive decrease in the level of YAPdeltaCs, prosurvival isoforms of YAP, in the spinal cord of transgenic mouse carrying a mutant SOD1 gene.

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal disease caused by the selective death of motor neurons. Between 5% and 10% of ALS patients have a genetically inherited form of the disease known as familial ALS (FALS), and approximately 20% of FALS patients have mutations in the SOD1 gene. Although the mechanism underlying motor neuron death has not yet been fully clarified, it is supposed to be not completely consistent with apoptosis, necrosis, or autophagic cell death. Recently, it was found that general transcriptional repression induces slowly progressive atypical cell death associated with the shift of balance between YAPdeltaCs as prosurvival factors and activated p73 promoting apoptosis. This type of neuronal death was named transcriptional repression-induced atypical death (TRIAD). Therefore, to investigate possible relationships between the mechanism of motor neuron death in ALS and TRIAD, G93ASOD1 transgenic mice (Tg) were examined as an ALS model. The levels of YAPdeltaCs in the spinal cords of Tg mice decreased with disease progression, even during the presymptomatic stage, whereas FL-YAP, a p73 cofactor that promotes apoptosis, was preserved until the late symptomatic stage. Although the expression of total p73 also decreased with age in Tg mice, the ratio of phosphorylated p73 to total p73 increased during the late symptomatic stage in Tg mice. These results suggest that the progressive decrease in the levels of YAPdeltaCs and the relative increase in phosphorylation of p73 over the time course are correlated with disease progression in ALS model animals.

Therapeutic strategy for ischemic stroke.

Possible strategies for treating ischemic stroke include: (1) Neuroprotection: preventing damaged neurons from undergoing apoptosis in the acute phase of cerebral ischemia; (2) Stem cell therapy: the repair of broken neuronal networks with newly born neurons in the chronic phase of cerebral ischemia. Firstly, we studied the neuroprotective effect of a calcium channel blocker, azelnidipine, or a by-product of heme degradation, biliverdin, in the ischemic brain. These results revealed both azelnidipine and biliverdin had a neuroprotective effect in the ischemic brain through their anti-oxidative property. Secondly, we investigated the role of granulocyte colony-stimulating factor (G-CSF) by administering G-CSF to rats after cerebral ischemia and found G-CSF plays a critical role in neuroprotection. Lastly, we developed a restorative stroke therapy with a bio-affinitive scaffold, which is able to provide an appropriate environment for newly born neurons. In the future, we will combine these strategies to develop more effective therapies for treatment of strokes.

Early detachment of neuromuscular junction proteins in ALS mice with SODG93A mutation.

The transgenic animals with mutant copper/zinc superoxide dismutase (SOD1) DNA develop paralytic motor neuron disease resembling human amyotrophic lateral sclerosis (ALS) patients and are commonly used as models for ALS. In the transgenic (Tg) mice with the G93A mutation of the human SOD1 gene SOD1(G93A) mice), the loss of ventral root axons and the synapses between the muscles and the motor neurons suggested that the motor neuron degeneration might proceed in a dying-back degeneration pattern. To reveal the relationship between axonal degeneration and the progression of the muscle atrophy in the SOD1(G93A) mice, we investigated the status of the neuromuscular junction along the disease progression. As a presynaptic or postsynaptic marker of neuromuscular junction (NMJ), anti-synaptic vesicle protein 2 (anti-SV2) antibody and α-bungarotoxin (α-BuTX) were chosen in this study and, as a marker of synaptic cleft, anti-agrin antibody was chosen in this study. In the immunohistochemistry of α-BuTX and anti-SV2 antibody, the percentages of double positive NMJs among α-BuTX single positive were decreased in Tg mice through time from ten weeks. The number of postsynaptic acethylcholine receptor (AChR) clusters did not decrease in Tg mice even at the end stage. Immunohistochemistry of α-BuTX and anti-agrin antibody revealed that the increase of immunopositive area of anti-agrin antibody around the muscle fiber in Tg mice from ten weeks of age. In this study, we revealed that the detachment of nerve terminals started at ten weeks in Tg mice. The levels of AChR did not change throughout 5-20 weeks of age in both groups of mice, and AChR remains clustering at NMJs, suggesting that the muscle abnormality is the result of detachment of nerve terminals.

Differentiation of PA from early PSP with different patterns of symptoms and CBF reduction.

OBJECTIVE: To clarify the features of pure akinesia (PA) and progressive supranuclear palsy (PSP) in the early stage of disease. METHODS: We investigated 15 PA and 41 PSP patients' clinical and radiologic features including head MRI, ethyl cysteinate dimmer-single photon emission-computed tomography (ECD-SPECT) and iodine-123 meta-iodobenzyl guanidine (123I-MIBG) myocardial scintigraphy. In ECD-SPECT study, cerebral blood flow (CBF) reduction was quantitatively expressed as Z-score, and that in the frontal lobe was evaluated. RESULTS: Many PSP patients claimed falls as the initial symptom but no PA patients did. Eye movement, as well as optokinetic nystagmus elicitation, was more frequently disturbed in PSP. Dementia, dysarthria and rigidity were also more frequent in PSP than in PA. Midbrain tegmentum atrophy in head MRI was more frequently observed in PSP. CBF in the frontal lobe, especially in the frontal eye field, was significantly lower in PSP than in PA. MIBG myocardial scintigraphy showed no difference between two groups. DISCUSSION: PA and PSP show distinct symptoms from the early stage, indicating that they are distinct disorders. The occurrence of falls and eye movement disturbance, as well as CBF reduction at the frontal eye field, is very important for distinguishing these disorders.

Therapeutic benefits of intrathecal protein therapy in a mouse model of amyotrophic lateral sclerosis.

When fused with the protein transduction domain (PTD) derived from the human immunodeficiency virus TAT protein, proteins can cross the blood-brain barrier and cell membrane and transfer into several tissues, including the brain, making protein therapy feasible for various neurological disorders. We have constructed a powerful antiapoptotic modified Bcl-X(L) protein (originally constructed from Bcl-X(L)) fused with PTD derived from TAT (TAT-modified Bcl-X(L)), and, to examine its clinical effectiveness in a mouse model of familial amyotrophic lateral sclerosis (ALS), transgenic mice expressing human Cu/Zn superoxide dismutase (SOD1) bearing a G93A mutation were treated by intrathecal infusion of TAT-modified Bcl-X(L). We demonstrate that intrathecally infused TAT-fused protein was effectively transferred into spinal cord neurons, including motor neurons, and that intrathecal infusion of TAT-modified Bcl-X(L) delayed disease onset, prolonged survival, and improved motor performance. Histological studies show an attenuation of motor neuron loss and a decrease in the number of cleaved caspase 9-, cleaved caspase 3-, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells in the lumbar cords of TAT-modified Bcl-X(L)-treated G93A mice. Our results indicate that intrathecal protein therapy using a TAT-fused protein is an effective clinical tool for the treatment of ALS.

Gelatin-siloxane hybrid scaffolds with vascular endothelial growth factor induces brain tissue regeneration.

In the brain after infarction or trauma, the tissue becomes pannecrotic and forms a cavity. In such situation, a scaffold is necessary to produce new tissue. In this study, we implanted a new porous gelatin-siloxane hybrid derived from gelatin and 3-(glycidoxypropyl) trimethoxysilane (gelatin-GPTMS) scaffolds into a brain defect, and investigated whether it makes a new brain tissue. In addition, vascular endothelial growth factor (VEGF) was added on gelatin-GPTMS scaffolds and its effect on tissue regeneration was examined. At 30 days after the implantation, the marginal territory of the scaffolds became occupied by newly formed tissue. Immunohistochemical analysis revealed that the new tissue was constituted by endothelial, astroglial and microglial cells, some of which were labeled for bromodeoxyuridine (BrdU). Addition of VEGF promoted numbers of these cells. Thus, combination of gelatin-GPTMS scaffolds and VEGF is preferable for brain regeneration.

Reduction of cerebral infarction in rats by biliverdin associated with amelioration of oxidative stress.

Biliverdin (BV), one of the byproducts of heme catalysis through heme oxygenase (HO) system, is a scavenger of reactive oxygen species (ROS). We hypothesized that BV treatment could protect rat brain cells from oxidative injuries via its anti-oxidant efficacies. Cerebral infarction was induced by transient middle cerebral artery occlusion (tMCAO) for 90 min, followed by reperfusion. BV or vehicle was administered intraperitoneally immediately after reperfusion. The size of the cerebral infarction 2 days after tMCAO was evaluated by 2,3,5-triphenyltetrazolium chloride (TTC) stain. Superoxide generation 4 h after tMCAO was determined by detection of oxidized hydroethidine. In addition, the oxidative impairment of neurons were immunohistochemically assessed by stain for lipid peroxidation with 4-hydroxy-2-nonenal (4-HNE) and damaged DNA with 8-hydroxy-2'-deoxyguanosine (8-OHdG). BV treatment significantly reduced infarct volume of the cerebral cortices associated with less superoxide production and decreased oxidative injuries of brain cells. The present study demonstrated that treatment with BV ameliorated the oxidative injuries on neurons and decreased brain infarct size in rat tMCAO model.

Macrophage infiltration, lectin-like oxidized-LDL receptor-1, and monocyte chemoattractant protein-1 are reduced by chronic HMG-CoA reductase inhibition.

Statin reduces cerebrovascular events independent of its cholesterol lowering effect. We hypothesized that statin inhibits early atherosclerotic change in common carotid artery (CCA), and investigated its effect on lectin-like oxidized-LDL receptor-1 (LOX-1) and monocyte chemoattractant protein-1 (MCP-1) expression, both of which are early atherosclerotic markers. Stroke-prone spontaneous hypertensive rats (SHR-SP) of 8 weeks old were orally treated with vehicle or simvastatin (20mg/kg) daily. After 4 weeks of simvastatin or vehicle treatment, or 2 weeks of vehicle and 2 weeks of simvastatin treatment, CCA was removed. LOX-1 and MCP-1 expression as well as macrophage infiltration were histologically investigated. Lipid deposition was also investigated by Sudan III staining. Simvastatin groups showed significantly smaller amount of lipid deposition and LOX-1 and MCP-1 expression, independent of serum lipid levels. Macrophage infiltration was also decreased. Reduction of cerebrovascular events by statins may be brought by the direct inhibition of atherosclerotic change.

Prevention of neuronal damage by calcium channel blockers with antioxidative effects after transient focal ischemia in rats.

BACKGROUND: Cerebral ischemia is a major leading cause of death and at the first place cause of disability all over the world. There are a lot of drugs that are in experimental stage for treatment of stroke. Among them are calcium channel blockers (CCBs) that have, in animal models, different effectiveness in healing of ischemic damage in brain. Mechanism of CCBs' action in cerebral ischemia is still unclear, but antioxidative property is supposed to be implicated. In the present study, we investigated antioxidative and neuroprotective properties of two CCBs, azelnidipine and amlodipine. METHODS: Male Wistar Kyoto rats were subjected to 90 min of transient middle cerebral artery occlusion (MCAO) by a nylon thread. Animals were divided into 3 groups, vehicle, azelnidipine and amlodipine group. In the azelnidipine and amlodipine groups, rats were treated with azelnidipine (1 mg/kg) and amlodipine (1 mg/kg) by gastric gavage for 2 weeks before MCAO. Vehicle group was treated by solution of methyl cellulose for 2 weeks. Rats were killed 24 h after MCAO. Physiological parameters (mean arterial pressure, heart rate, body weight), infarct volume, brain edema index, cerebral blood flow (CBF), oxidative stress markers which are HEL, 4-HNE, AGE and 8-OHdG, and evidence of apoptosis by TUNEL, were investigated. RESULTS: There were no significant differences among groups in mean arterial pressure, heart rate and body weight. Treatment with azelnidipine and amlodipine reduced infarct volume and brain edema. Azelnidipine treated group showed more marked reduction of infarct volume and cerebral edema than amlodipine group. There was no attenuation of CBF in CCBs groups. The number of HEL, 4-HNE, AGE and 8-OHdG positive cells were significantly decreased in the CCBs treated groups. These molecules were again fewer in the azelnidipine group than in the amlodipine group. In TUNEL staining, the numbers of positive cells was smaller in the CCBs treated groups, especially in the azelnidipine group. CONCLUSIONS: Pretreatment of azelnidipine and amlodipine had a neuroprotective effect in ischemic brain. Antioxidative property is one of the important profiles of CCBs that is implicated in brain protection.

Increased autophagy in transgenic mice with a G93A mutant SOD1 gene.

Autophagy, like the ubiquitin-proteasome system, is considered to play an important role in preventing the accumulation of abnormal proteins. Rat microtubule-associated protein 1 light chain 3 (LC3) is important for autophagy, and the conversion from LC3-I into LC3-II is accepted as a simple method for monitoring autophagy. We examined a SOD1G93A transgenic mouse model for amyotrophic lateral sclerosis (ALS) to consider a possible relationship between autophagy and ALS. In our study we analyzed LC3 and mammalian target of rapamycin (mTOR), a suppressor of autophagy, by immunoassays. The level of LC3-II, which is known to be correlated with the extent of autophagosome formation, was increased in SOD1G93A transgenic mice at symptomatic stage compared with non-transgenic or human wild-type SOD1 transgenic animals. Moreover, the ratio of phosphorylated mTOR/Ser2448 immunopositive motor neurons to total motor neurons was decreased in SOD1G93A-Tg mice. The present data show the possibility of increased autophagy in an animal model for ALS. And autophagy may be partially regulated by an mTOR signaling pathway in these animals.

Two cases of spinocerebellar ataxia accompanied by involvement of the skeletal motor neuron system and bulbar palsy.

We report two patients with spinocerebellar ataxia (SCA) with cranial and spinal motor neuron involvement. They initially presented with cerebellar ataxia, followed by bulbar palsy and limb motor neuron sign. One of the patients had a brother with allied disorder. SCA type 1 (SCA1), SCA3 and SCA6 have been reported to involve the motor neuron system, but they were excluded by DNA analyses in the present two patients. These two patients may form a distinct disease entity among SCAs.