Striatal parvalbumin interneurons are activated in a mouse model of cerebellar dystonia

Dystonia is thought to arise from abnormalities in the motor loop of the basal ganglia; however, there is an ongoing debate regarding cerebellar involvement. We adopted an established cerebellar dystonia mouse model by injecting ouabain to examine the contribution of the cerebellum. Initially, we examined whether the entopeduncular nucleus (EPN), substantia nigra pars reticulata (SNr), globus pallidus externus (GPe) and striatal neurons were activated in the model. Next, we examined whether administration of a dopamine D1 receptor agonist and dopamine D2 receptor antagonist or selective ablation of striatal parvalbumin (PV, encoded by Pvalb)-expressing interneurons could modulate the involuntary movements of the mice. The cerebellar dystonia mice had a higher number of cells positive for c-fos (encoded by Fos) in the EPN, SNr and GPe, as well as a higher positive ratio of c-fos in striatal PV interneurons, than those in control mice. Furthermore, systemic administration of combined D1 receptor agonist and D2 receptor antagonist and selective ablation of striatal PV interneurons relieved the involuntary movements of the mice. Abnormalities in the motor loop of the basal ganglia could be crucially involved in cerebellar dystonia, and modulating PV interneurons might provide a novel treatment strategy.

Cranial geometry in patients with dystonia and Parkinson's disease

Abnormal skull shape has been reported in brain disorders. However, no studies have investigated cranial geometry in neurodegenerative disorders. This study aimed to evaluate the cranial geometry of patients with dystonia or Parkinson's disease (PD). Cranial computed tomography images of 36 patients each with idiopathic dystonia (IDYS), PD, and chronic subdural hematoma (CSDH) were analyzed. Those with IDYS had a significantly higher occipital index (OI) than those with CSDH (p = 0.014). When cephalic index (CI) was divided into the normal and abnormal groups, there was a significant difference between those with IDYS and CSDH (p = 0.000, α = 0.017) and between PD and CSDH (p = 0.031, α = 0.033). The age of onset was significantly correlated with the CI of IDYS (τ = - 0.282, p = 0.016). The Burke-Fahn-Marsden Dystonia Rating Scale motor score (BFMDRS-M) showed a significant correlation with OI in IDYS (τ = 0.372, p = 0.002). The cranial geometry of patients with IDYS was significantly different from that of patients with CSDH. There was a significant correlation between age of onset and CI, as well as between BFMDRS-M and OI, suggesting that short heads in the growth phase and skull balance might be related to the genesis of dystonia and its effect on motor symptoms.

Long-sheath Introducer-assisted Revascularization (L-SHARE) Technique for Treating Large-vessel Occlusion by a Giant Clot

Revascularization for common carotid artery (CCA) occlusion might be difficult. We reported our strategy for revascularizing CCA occlusion by giant clots. A 94-year-old woman was transferred to our hospital because of right hemiparesis and aphasia. CCA occlusion and giant clots were detected on ultrasonography. We performed mechanical thrombectomy using a 9-Fr balloon-guiding catheter, stent retriever, and aspiration catheter through a 9-Fr long-sheath introducer [long-sheath introducer-assisted revascularization (L-SHARE) technique]. We successfully recanalized CCA occlusion using this method. The L-SHARE technique might be useful for recanalization of CCA occlusion.

Diagnosis and Treatment of Tremor in Parkinson's Disease Using Mechanical Devices

BACKGROUND

Parkinsonian tremors are sometimes confused with essential tremors or other conditions. Recently, researchers conducted several studies on tremor evaluation using wearable sensors and devices, which may support accurate diagnosis. Mechanical devices are also commonly used to treat tremors and have been actively researched and developed. Here, we aimed to review recent progress and the efficacy of the devices related to Parkinsonian tremors.

METHODS

The PubMed and Scopus databases were searched for articles. We searched for "Parkinson disease" and "tremor" and "device".

RESULTS

Eighty-six articles were selected by our systematic approach. Many studies demonstrated that the diagnosis and evaluation of tremors in patients with PD can be done accurately by machine learning algorithms. Mechanical devices for tremor suppression include deep brain stimulation (DBS), electrical muscle stimulation, and orthosis. In recent years, adaptive DBS and optimization of stimulation parameters have been studied to further improve treatment efficacy.

CONCLUSIONS

Due to developments using state-of-the-art techniques, effectiveness in diagnosing and evaluating tremor and suppressing it using these devices is satisfactorily high in many studies. However, other than DBS, no devices are in practical use. To acquire high-level evidence, large-scale studies and randomized controlled trials are needed for these devices.

Therapeutic Devices for Motor Symptoms in Parkinson’s Disease: Current Progress and a Systematic Review of Recent Randomized Controlled Trials

Background

Pharmacotherapy is the first-line treatment option for Parkinson’s disease, and levodopa is considered the most effective drug for managing motor symptoms. However, side effects such as motor fluctuation and dyskinesia have been associated with levodopa treatment. For these conditions, alternative therapies, including invasive and non-invasive medical devices, may be helpful. This review sheds light on current progress in the development of devices to alleviate motor symptoms in Parkinson’s disease.

Methods

We first conducted a narrative literature review to obtain an overview of current invasive and non-invasive medical devices and thereafter performed a systematic review of recent randomized controlled trials (RCTs) of these devices.

Results

Our review revealed different characteristics of each device and their effectiveness for motor symptoms. Although invasive medical devices are usually highly effective, surgical procedures can be burdensome for patients and have serious side effects. In contrast, non-pharmacological/non-surgical devices have fewer complications. RCTs of non-invasive devices, especially non-invasive brain stimulation and mechanical peripheral stimulation devices, have proven effectiveness on motor symptoms. Nearly no non-invasive devices have yet received Food and Drug Administration certification or a CE mark.

Conclusion

Invasive and non-invasive medical devices have unique characteristics, and several RCTs have been conducted for each device. Invasive devices are more effective, while non-invasive devices are less effective and have lower hurdles and risks. It is important to understand the characteristics of each device and capitalize on these.

Ataxia with vitamin E deficiency in the Philippines : A case report of two siblings

Here we report two siblings with ataxia and peripheral neuropathy. One patient showed head tremors. Genetic analysis revealed a mutation in the hepatic α-tocopherol transfer protein (α-TTP) gene (TTPA) on chromosome 8q13. They were diagnosed with ataxia with vitamin E deficiency which is firstly reported in the Philippines. As the symptoms of ataxia with vitamin E deficiency can be alleviated with lifelong vitamin E administration, differential diagnosis from similar syndromes is important. In addition, ataxia with vitamin E deficiency causes movement disorders. Therefore, a common hereditary disease in the Philippines, X-linked dystonia-parkinsonism, could be another differential diagnosis. The Philippines is an archipelago comprising 7,107 islands, and the prevalence of rare hereditary diseases among the populations of small islands is still unclear. For neurologists, establishing a system of genetic diagnosis and counseling in rural areas remains challenging. These unresolved problems should be addressed in the near future. J. Med. Invest. 68 : 400-403, August, 2021.

Percutaneous Transluminal Angioplasty and Stenting Using an Aspiration Catheter

Objective

During percutaneous transluminal angioplasty (PTA) for the vertebral artery, occlusion of the subclavian artery using a balloon guiding catheter may be useful to prevent embolism of clots and/or debris distal to an atherosclerotic lesion. However, when placing a balloon guiding catheter at the intended vessels is difficult, it may be useful to use an aspiration catheter (AC) for mechanical thrombectomy as an intermediate catheter to suction way clots and/or debris. We report two cases in which PTA was performed for an atherosclerotic lesion at the intracranial vertebral artery using an AC, which ended without complications.

Case Presentations

Case 1: A 74-year-old man presented with dysarthria and was admitted to our hospital. MRI revealed severe left vertebral artery stenosis and diffuse cerebral infarct areas at the territory of the posterior circulation. The patient had an abdominal aortic aneurysm and abnormally shaped left tortuous subclavian artery. Therefore, we performed PTA and stenting via the left brachial artery. We guided a 6-Fr long sheath to the left subclavian artery, and a 6-Fr AC for thrombectomy was guided through the long sheath to the V4 portion of the left vertebral artery. Thereafter, PTA was carried out under manual aspiration from the AC. As restenosis at the atherosclerotic lesion occurred after PTA, we performed stenting using a coronary stent system for this lesion under manual aspiration from the AC. No new infarct areas were observed on post-procedural MRI. Case 2: A 74-year-old woman presented with dysarthria and was admitted to our hospital. MRI demonstrated basilar artery occlusion and diffuse cerebral infarct areas at the territory of the posterior circulation. As her symptom worsened after admission, we performed urgent mechanical thrombectomy. We first performed thrombectomy using a stent retriever and then performed PTA and stenting (PTAS) for residual basilar artery stenosis via the AC under manual aspiration.

Conclusion

When it is difficult to place a guiding catheter at the intended vessels during PTA, an AC may be useful to prevent distal embolization.

Dystonia and Cerebellum: From Bench to Bedside

Dystonia pathogenesis remains unclear; however, findings from basic and clinical research suggest the importance of the interaction between the basal ganglia and cerebellum. After the discovery of disynaptic pathways between the two, much attention has been paid to the cerebellum. Basic research using various dystonia rodent models and clinical studies in dystonia patients continues to provide new pieces of knowledge regarding the role of the cerebellum in dystonia genesis. Herein, we review basic and clinical articles related to dystonia focusing on the cerebellum, and clarify the current understanding of the role of the cerebellum in dystonia pathogenesis. Given the recent evidence providing new hypotheses regarding dystonia pathogenesis, we discuss how the current evidence answers the unsolved clinical questions.

Spatiotemporal Up-Regulation of Mu Opioid Receptor 1 in Striatum of Mouse Model of Huntington's Disease Differentially Affecting Caudal and Striosomal Regions

The striatum of humans and other mammals is divided into macroscopic compartments made up of a labyrinthine striosome compartment embedded in a much larger surrounding matrix compartment. Anatomical and snRNA-Seq studies of the Huntington’s disease (HD) postmortem striatum suggest a preferential decline of some striosomal markers, and mRNAs studies of HD model mice concur. Here, by immunohistochemical methods, we examined the distribution of the canonical striosomal marker, mu-opioid receptor 1 (MOR1), in the striatum of the Q175 knock-in mouse model of HD in a postnatal time series extending from 3 to 19 months. We demonstrate that, contrary to the loss of many markers for striosomes, there is a pronounced up-regulation of MOR1 in these Q175 knock-in mice. We show that in heterozygous Q175 knock-in model mice [~192 cytosine-adenine-guanine (CAG) repeats], this MOR1 up-regulation progressed with advancing age and disease progression, and was particularly remarkable at caudal levels of the striatum. Given the known importance of MOR1 in basal ganglia signaling, our findings, though in mice, should offer clues to the pathogenesis of psychiatric features, especially depression, reinforcement sensitivity, and involuntary movements in HD.

Factors associated with DWI-ASPECTS score in patients with acute ischemic stroke due to cerebral large vessel occlusion

BACKGROUND

The Alberta Stroke Program Early CT score (ASPECTS) of patients with acute ischemic stroke at the time of admission varies. It is crucial to select appropriate methods of treatment, such as recombinant tissue-plasminogen activator, and/or endovascular thrombectomy. According to the recent guidelines, endovascular thrombectomy for patients with large vessel occlusion (LVO) and lesion of ischemic tissue that was not yet infarcted is effective. This result demonstrates the importance of patient selection based on neuroradiological imaging. However, there are many patients who are judged as ineligibility for recanalization therapy because of presence of large ischemic core, indicating unfavorable ASPECTS, at the time of admission. We investigated the factors associated with favorable diffusion-weighted image (DWI)-ASPECTS score at the time of admission.

METHODS

We studies patients with LVO within 24 h from onset who were admitted into our hospital. We divided them into two groups, with favorable DWI-ASPECTS (≥6), and unfavorable DWI-ASPECTS (<6) at the time of admission. We investigated factors associated with favorable DWI-ASPECTS by evaluation of our patients' severity of clinical symptom, etiology, and radiological findings.

RESULTS

This study showed that mild white matter lesion (Fazekas scale ≤1), absence of internal carotid artery (ICA) occlusion and cardioembolic stroke were independent factor of favorable DWI-ASPECTS at the time of admission. (odds ratio 12.92, p <  0.001, odds ratio 0.31, p =  0.001, odds ratio 0.16, p = 0.001, respectively) CONCLUSIONS: Absence of severe white matter lesion, cardioembolic stroke, and ICA occlusion might be associated with favorable DWI-ASPECTS at the time of admission.

Basic research and surgical techniques for brain arteriovenous malformations

Arteriovenous malformations (AVMs) are hemorrhagic vascular diseases in which arteries and veins are directly connected with no capillary bed between the two. We herein introduce the results of basic research of this disease and surgical techniques based on our data and experiences. The results obtained from our research show that cell death- and inflammation-related molecules changed or became activated compared with control specimens. These findings indicate that chronic inflammation occurs in and around the nidus of AVMs. Various molecules are involved in the mechanisms of cell death and angiogenesis during this process. Confirmation of blood flow in the nidus is very important to avoid hemorrhagic complications during surgical removal of the nidus. The risk of hemorrhage increases when the blood flow in the nidus is not reduced. We reported the advantages of serial indocyanine green videoangiography, which is used to assess the blood flow during AVM nidus removal. Since publication of the ARUBA trial and Scottish Audit, treatments with high morbidity have not been allowed. It is especially important for neurosurgeons to treat low Spetzler-Martin grade AVMs with low morbidity. J. Med. Invest. 67 : 222-228, August, 2020.

Clinical Outcome and Intraoperative Neurophysiology of the Lance-Adams Syndrome Treated with Bilateral Deep Brain Stimulation of the Globus Pallidus Internus: A Case Report and Review of the Literature

BACKGROUND

The Lance-Adams syndrome (LAS) is a myoclonus syndrome caused by hypoxic-ischemic encephalopathy. LAS cases could be refractory to first-line medications, and the neuronal mechanism underlying LAS pathology remains unknown.

OBJECTIVES

To describe a patient with LAS who underwent bilateral globus pallidus internus (GPi) stimulation and discuss the pathophysiology of LAS with intraoperative electrophysiological findings.

PATIENTS

A 79-year-old woman presented with a history of cardiopulmonary arrest due to internal carotid artery rupture following carotid endarterectomy after successful cardiopulmonary resuscitation. However, within 1 month, the patient developed sensory stimulation-induced myoclonus in her face and extremities. Because her myoclonic symptoms were refractory to pharmacotherapy, deep brain stimulation of the GPi was performed 1 year after the hypoxic attack.

RESULTS

Continuous bilateral GPi stimulation with optimal parameter settings remarkably improved the patient's myoclonic symptoms. At the 2-year follow-up, her Unified Myoclonus Rating Scale score decreased from 90 to 24. In addition, we observed burst firing and interburst pause patterns on intraoperative microelectrode recordings of the bilateral GPi and stimulated this area as the therapeutic target.

CONCLUSION

Our results show that impairment in the basal ganglion circuitry might be involved in the pathogenesis of myoclonus in patients with LAS.

Turning on the Left Side Electrode Changed Depressive State to Manic State in a Parkinson's Disease Patient Who Received Bilateral Subthalamic Nucleus Deep Brain Stimulation: A Case Report

No previous reports have described a case in which deep brain stimulation elicited an acute mood swing from a depressive to manic state simply by switching one side of the bilateral deep brain stimulation electrode on and off. The patient was a 68-year-old woman with a 10-year history of Parkinson’s disease. She underwent bilateral subthalamic deep brain stimulation surgery. After undergoing surgery, the patient exhibited hyperthymia. She was scheduled for admission. On the first day of admission, it was clear that resting tremors in the right limbs had relapsed and her hyperthymia had reverted to depression. It was discovered that the left-side electrode of the deep brain stimulation device was found to be accidentally turned off. As soon as the electrode was turned on, motor impairment improved and her mood switched from depression to mania. The authors speculate that the lateral balance of stimulation plays an important role in mood regulation. The current report provides an intriguing insight into possible mechanisms of mood swing in mood disorders.

Phenotype variability and allelic heterogeneity in KMT2B-Associated disease

BACKGROUND

Mutations in Lysine-Specific Histone Methyltransferase 2B gene (KMT2B) have been reported to be associated with complex early-onset dystonia. Almost all reported KMT2B mutations occurred de novo in the paternal germline or in the early development of the patient. We describe clinico-genetic features on four Japanese patients with novel de novo mutations and demonstrate the phenotypic spectrum of KMT2B mutations.

METHODS

We performed genetic studies, including trio-based whole exome sequencing (WES), in a cohort of Japanese patients with a seemingly sporadic early-onset generalized combined dystonia. Potential effects by the identified nucleotide variations were evaluated biologically. Genotype-phenotype correlations were also investigated.

RESULTS

Four patients had de novo heterozygous mutations in KMT2B, c.309delG, c.1656dupC, c.3325_3326insC, and c.5636delG. Biological analysis of KMT2B mRNA levels showed a reduced expression of mutant transcript frame. All patients presented with motor milestone delay, microcephaly, mild psychomotor impairment, childhood-onset generalized dystonia and superimposed choreoathetosis or myoclonus. One patient cannot stand due to axial hypotonia associated with cerebellar dysfunction. Three patients had bilateral globus pallidal deep brain stimulation (DBS) with excellent or partial response.

CONCLUSIONS

We further demonstrate the allelic heterogeneity and phenotypic variations of KMT2B-associated disease. Haploinsufficiency is one of molecular pathomechanisms underlying the disease. Cardinal clinical features include combined dystonia accompanying mild psychomotor disability. Cerebellum would be affected in KMT2B-associated disease.

Clinicopathological Phenotype and Genetics of X-Linked Dystonia-Parkinsonism (XDP; DYT3; Lubag)

X-linked dystonia–parkinsonism (XDP; OMIM314250), also referred to as DYT3 dystonia or “Lubag” disease, was first described as an endemic disease in the Philippine island of Panay. XDP is an adult-onset movement disorder characterized by progressive and severe dystonia followed by overt parkinsonism in the later years of life. Among the primary monogenic dystonias, XDP has been identified as a transcriptional dysregulation syndrome with impaired expression of the TAF1 (TATA box-binding protein associated factor 1) gene, which is a critical component of the cellular transcription machinery. The major neuropathology of XDP is progressive neuronal loss in the neostriatum (i.e., the caudate nucleus and putamen). XDP may be used as a human disease model to elucidate the pathomechanisms by which striatal neurodegeneration leads to dystonia symptoms. In this article, we introduce recent advances in the understanding of the interplay between pathophysiology and genetics in XDP.

Striatal Vulnerability in Huntington's Disease: Neuroprotection Versus Neurotoxicity

Huntington’s disease (HD) is an autosomal dominant neurodegenerative disease caused by the expansion of a CAG trinucleotide repeat encoding an abnormally long polyglutamine tract (PolyQ) in the huntingtin (Htt) protein. In HD, striking neuropathological changes occur in the striatum, including loss of medium spiny neurons and parvalbumin-expressing interneurons accompanied by neurodegeneration of the striosome and matrix compartments, leading to progressive impairment of reasoning, walking and speaking abilities. The precise cause of striatal pathology in HD is still unknown; however, accumulating clinical and experimental evidence suggests multiple plausible pathophysiological mechanisms underlying striatal neurodegeneration in HD. Here, we review and discuss the characteristic neurodegenerative patterns observed in the striatum of HD patients and consider the role of various huntingtin-related and striatum-enriched proteins in neurotoxicity and neuroprotection.

Dopamine-Induced Changes in Gαolf Protein Levels in Striatonigral and Striatopallidal Medium Spiny Neurons Underlie the Genesis of l-DOPA-Induced Dyskinesia in Parkinsonian Mice

The dopamine precursor, l-3,4-dihydroxyphenylalanine (l-DOPA), exerts powerful therapeutic effects but eventually generates l-DOPA-induced dyskinesia (LID) in patients with Parkinson’s disease (PD). LID has a close link with deregulation of striatal dopamine/cAMP signaling, which is integrated by medium spiny neurons (MSNs). Olfactory type G-protein α subunit (Gα_olf), a stimulatory GTP-binding protein encoded by the GNAL gene, is highly concentrated in the striatum, where it positively couples with dopamine D₁ (D₁R) receptor and adenosine A_2A receptor (A_2AR) to increase intracellular cAMP levels in MSNs. In the striatum, D₁Rs are mainly expressed in the MSNs that form the striatonigral pathway, while D₂Rs and A_2ARs are expressed in the MSNs that form the striatopallidal pathway. Here, we examined the association between striatal Gα_olf protein levels and the development of LID. We used a hemi-parkinsonian mouse model with nigrostriatal lesions induced by 6-hydroxydopamine (6-OHDA). Using quantitative immunohistochemistry (IHC) and a dual-antigen recognition in situ proximity ligation assay (PLA), we here found that in the dopamine-depleted striatum, there appeared increased and decreased levels of Gα_olf protein in striatonigral and striatopallidal MSNs, respectively, after a daily pulsatile administration of l-DOPA. This leads to increased responsiveness to dopamine stimulation in both striatonigral and striatopallidal MSNs. Because Gα_olf protein levels serve as a determinant of cAMP signal-dependent activity in striatal MSNs, we suggest that l-DOPA-induced changes in striatal Gα_olf levels in the dopamine-depleted striatum could be a key event in generating LID.

Putaminal Mosaic Visualized by Tyrosine Hydroxylase Immunohistochemistry in the Human Neostriatum

Among the basal ganglia-thalamocortical circuits, the putamen plays a critical role in the “motor” circuits that control voluntary movements and motor learning. The human neostriatum comprises two functional subdivisions known as the striosome (patch) and matrix compartments. Accumulating evidence suggests that compartment-specific dysregulations of dopamine activity might be involved in the disease-specific pathology and symptoms of human striatal diseases including movement disorders. This study was undertaken to examine whether or how striatal dopaminergic innervations are organized into the compartmentalized architecture found in the putamen of adult human brains. For this purpose, we used a highly sensitive immunohistochemistry (IHC) technique to identify tyrosine hydroxylase (TH; EC 1.14.16.2), a marker for striatal dopaminergic axons and terminals, in formalin-fixed paraffin-embedded (FFPE) tissues obtained from autopsied human brains. Herein, we report that discrete compartmentalization of TH-labeled innervations occurs in the putamen, as in the caudate nucleus (CN), with a higher density of TH labeling in the matrix compared to the striosomes. Our results provide anatomical evidence to support the hypothesis that compartment-specific dysfunction of the striosome-matrix dopaminergic systems might contribute to the genesis of movement disorders.

Therapeutic Perspective on Tardive Syndrome with Special Reference to Deep Brain Stimulation

Tardive syndrome (TDS) is a potentially permanent and irreversible hyperkinetic movement disorder caused by exposure to dopamine receptor blocking agents. Guidelines published by the American Academy of Neurology recommend pharmacological first-line treatment for TDS with clonazepam (level B), ginkgo biloba (level B), amantadine (level C), and tetrabenazine (level C). Recently, a class II study provided level C evidence for use of deep brain stimulation (DBS) of the globus pallidus internus (GPi) in patients with TDS. Although the precise pathogenesis of TDS remains to be elucidated, the beneficial effects of GPi-DBS in patients with TDS suggest that the disease may be a basal ganglia disorder. In addition to recent advances in understanding the pathophysiology of TDS, this article introduces the current use of DBS in the treatment of medically intractable TDS.

Postsynaptic Density Protein 95 in the Striosome and Matrix Compartments of the Human Neostriatum

The human neostriatum consists of two functional subdivisions referred to as the striosome (patch) and matrix compartments. The striosome-matrix dopamine systems play a central role in cortico-thalamo-basal ganglia circuits, and their involvement is thought to underlie the genesis of multiple movement and behavioral disorders, and of drug addiction. Human neuropathology also has shown that striosomes and matrix have differential vulnerability patterns in several striatal neurodegenerative diseases. Postsynaptic density protein 95 (PSD-95), also known as disks large homolog 4, is a major scaffolding protein in the postsynaptic densities of dendritic spines. PSD-95 is now known to negatively regulate not only N-methyl-D-aspartate glutamate signaling, but also dopamine D1 signals at sites of postsynaptic transmission. Accordingly, a neuroprotective role for PSD-95 against dopamine D1 receptor (D1R)-mediated neurotoxicity in striatal neurodegeneration also has been suggested. Here, we used a highly sensitive immunohistochemistry technique to show that in the human neostriatum, PSD-95 is differentially concentrated in the striosome and matrix compartments, with a higher density of PSD-95 labeling in the matrix compartment than in the striosomes. This compartment-specific distribution of PSD-95 was strikingly complementary to that of D1R. In addition to the possible involvement of PSD-95-mediated synaptic function in compartment-specific dopamine signals, we suggest that the striosomes might be more susceptible to D1R-mediated neurotoxicity than the matrix compartment. This notion may provide new insight into the compartment-specific vulnerability of MSNs in striatal neurodegeneration.

Development of a highly sensitive immunohistochemical method to detect neurochemical molecules in formalin-fixed and paraffin-embedded tissues from autopsied human brains

Immunohistochemistry (IHC) is a valuable method for identifying discrete neurochemical molecules by the interaction of target antigens with validated antibodies tagged with a visible label (e.g., peroxidase). We have developed an immunostaining method that is highly sensitive in detection of neurochemical antigens. Our IHC method, which we call the PBTA method, involves a hybrid protocol that implements aspects of both the polymer and avidin-biotin-complex (ABC) methods in combination with biotin-tyramide amplification. When using [Met]-enkephalin as a target antigen, the sensitivity of the PBTA method for IHC was more than 100-fold higher compared with the polymer and ABC methods. In addition, its sensitivity for enzyme-linked immunosorbent assay was about 1,000-fold higher compared with the ABC method. We examined the utility of our IHC method for both chromogenic and fluorescence detection systems used to visualize neurochemical peptides and proteins in formalin-fixed, paraffin-embedded tissues from autopsied human brains. The results convincingly demonstrate that under optimal conditions, our IHC method is highly sensitive without increasing non-specific background activities. Our IHC method could be a powerful tool for detection and visualization of neurochemical antigens that are present even in trace amounts in autopsied human brains.

Spinal Central Effects of Peripherally Applied Botulinum Neurotoxin A in Comparison between Its Subtypes A1 and A2

Because of its unique ability to exert long-lasting synaptic transmission blockade, botulinum neurotoxin A (BoNT/A) is used to treat a wide variety of disorders involving peripheral nerve terminal hyperexcitability. However, it has been a matter of debate whether this toxin has central or peripheral sites of action. We employed a rat model in which BoNT/A1 or BoNT/A2 was unilaterally injected into the gastrocnemius muscle. On time-course measurements of compound muscle action potential (CMAP) amplitudes after injection of BoNT/A1 or BoNT/A2 at doses ranging from 1.7 to 13.6 U, CMAP amplitude for the ipsilateral hind leg was markedly decreased on the first day, and this muscle flaccidity persisted up to the 14th day. Of note, both BoNT/A1 and BoNT/A2 administrations also resulted in decreased CMAP amplitudes for the contralateral leg in a dose-dependent manner ranging from 1.7 to 13.6 U, and this muscle flaccidity increased until the fourth day and then slowly recovered. Immunohistochemical results revealed that BoNT/A-cleaved synaptosomal-associated protein of 25 kDa (SNAP-25) appeared in the bilateral ventral and dorsal horns 4 days after injection of BoNT/A1 (10 U) or BoNT/A2 (10 U), although there seemed to be a wider spread of BoNT/A-cleaved SNAP-25 associated with BoNT/A1 than BoNT/A2 in the contralateral spinal cord. This suggests that the catalytically active BoNT/A1 and BoNT/A2 were axonally transported via peripheral motor and sensory nerves to the spinal cord, where they spread through a transcytosis (cell-to-cell trafficking) mechanism. Our results provide evidence for the central effects of intramuscularly administered BoNT/A1 and BoNT/A2 in the spinal cord, and a new insight into the clinical effects of peripheral BoNT/A applications.

Reversibility of ischemic findings on 3-tesla magnetic resonance T2(*)-weighted image after recanalization

Ischemic vessel signs (IVS) can be detected on 3-tesla T2(*)-weighted magnetic resonance images as a vessel enlargement at the territory of acute ischemia caused by major vessel occlusion or stenosis. Here, we studied changes in IVS before and after recanalization by the administration of intravenous recombinant tissue plasminogen activator (IV rtPA), carotid artery stenting or percutaneous transluminal angioplasty in patients with major vessel occlusion or stenosis. We performed magnetic resonance imaging for all patients treated by IV rtPA at the time of admission, shortly after and 24-72 hours after treatment with IV rtPA. We reviewed the IVS to assess its natural course of IVS by assessing patients who did not recanalize. IVS tended to disappear after recanalization. Conversely, in patients without recanalization, IVS did not disappear shortly after IV rtPA; rather, it disappeared 24-72 hours after IV rtPA, especially in the presence of complete infarction. Recanalization by IV rtPA or endovascular treatment contributed to improved clinical deficits or the prevention from further progression. IVS can be a parameter of misery perfusion and an important factor to detect the patients who have an indication of treatment for recanalization.

A novel tyrosine kinase inhibitor AMN107 (nilotinib) normalizes striatal motor behaviors in a mouse model of Parkinson's disease

Abnormal motor behaviors in Parkinson's disease (PD) result from striatal dysfunction due to an imbalance between dopamine and glutamate transmissions that are integrated by dopamine- and cAMP-regulated phosphoprotein of 32 kDa (DARPP-32). c-Abelson tyrosine kinase (c-Abl) phosphorylates cyclin-dependent kinase 5 (Cdk5) at Tyr15 to increase the activity of Cdk5, which reduces the efficacy of dopaminergic signaling by phosphorylating DARPP-32 at Thr75 in the striatum. Here, we report that in the mouse striatum, a novel c-Abl inhibitor, nilotinib (AMN107), inhibits phosphorylation of both Cdk5 at Tyr15 and DARPP-32 at Thr75, which is negatively regulated by dopamine receptor activation through a D2 receptor-mediated mechanism. Like a D2-agonist, nilotinib synergizes with a D1-agonist for inducing striatal c-Fos expression. Moreover, systemic administration of nilotinib normalizes striatal motor behaviors in a mouse model of PD induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. These findings suggest that nilotinib could possibly serve as a new and alternative agent for treating PD motor symptoms.

Brush sign on 3-T T2*-weighted MRI as a potential predictor of hemorrhagic transformation after tissue plasminogen activator therapy

BACKGROUND AND PURPOSE

The brush sign (BS) is the enlargement of medullary veins on 3-T T2*-weighted MRI seen in patients with ischemic stroke because of major cerebral artery occlusion. However, the clinical relevance of BS in patients with acute stroke remains unclear. We assessed the correlation between detecting BS with the development of hemorrhagic transformation after intravenous thrombolysis.

METHODS

We enrolled consecutive patients with M1 or M2 occlusion treated with intravenous tissue plasminogen activator. We classified the patients into 2 groups: the group positive for BS (P-BS) and the group negative for BS (N-BS). We investigated the differences in MRI findings and the clinical outcome between the 2 groups.

RESULTS

The subjects consisted of 36 patients (19 men; mean age, 74.7 years). Twenty-one patients (58%) had M1 occlusion, and 15 (42%) had M2 occlusion. Twenty-five patients (69%) were classified into the P-BS group and 11 (31%) into the N-BS group. Recanalization was observed in 15 (60%) and 10 (90%) patients in the P-BS and N-BS groups, respectively (P=0.116). Hemorrhagic transformation on MRI was observed more frequently in the P-BS group than in the N-BS group (64% versus 18%; P=0.027). A good outcome (mRS, 0-1) at discharge was found in 24% of patients in the P-BS group and in 45% of patients in the N-BS group (P=0.152). A multivariate logistic regression analysis revealed that the presence of BS (odds ratio, 9.08; 95% confidence interval, 1.4-59.8; P=0.022) was independently associated with hemorrhagic transformation.

CONCLUSIONS

BS may predict the development of hemorrhagic transformation in patients with acute stroke treated with intravenous tissue plasminogen activator.

Response of striosomal opioid signaling to dopamine depletion in 6-hydroxydopamine-lesioned rat model of Parkinson's disease: a potential compensatory role

The opioid peptide receptors consist of three major subclasses, namely, μ, δ, and κ (MOR, DOR, and KOR, respectively). They are involved in the regulation of striatal dopamine functions, and increased opioid transmissions are thought to play a compensatory role in altered functions of the basal ganglia in Parkinson's disease (PD). In this study, we used an immunohistochemistry with tyramide signal amplification (TSA) protocols to determine the distributional patterns of opioid receptors in the striosome-matrix systems of the rat striatum. As a most striking feature of striatal opioid anatomy, MORs are highly enriched in the striosomes and subcallosal streak. We also found that DORs are localized in a mosaic pattern in the dorsal striatum (caudate-putamen), with heightened labeling for DOR in the striosomes relative to the matrix compartment. In the 6-hydroxydopamine-lesioned rat model of PD, lesions of the nigrostriatal pathways caused a significant reduction of striatal labeling for both the MOR and DOR in the striosomes, but not in the matrix compartment. Our results suggest that the activities of the striosome and matrix compartments are differentially regulated by the opioid signals involving the MORs and DORs, and that the striosomes may be more responsive to opioid peptides (e.g., enkephalin) than the matrix compartment. Based on a model in which the striosome compartment regulates the striatal activity, we propose a potent compensatory role of striosomal opioid signaling under the conditions of the striatal dopamine depletion that occurs in PD.

Dopamine signaling negatively regulates striatal phosphorylation of Cdk5 at tyrosine 15 in mice

Striatal functions depend on the activity balance between the dopamine and glutamate neurotransmissions. Glutamate inputs activate cyclin-dependent kinase 5 (Cdk5), which inhibits postsynaptic dopamine signaling by phosphorylating DARPP-32 (dopamine- and cAMP-regulated phosphoprotein, 32 kDa) at Thr75 in the striatum. c-Abelson tyrosine kinase (c-Abl) is known to phosphorylate Cdk5 at Tyr15 (Tyr15-Cdk5) and thereby facilitates the Cdk5 activity. We here report that Cdk5 with Tyr15 phosphorylation (Cdk5-pTyr15) is enriched in the mouse striatum, where dopaminergic stimulation inhibited phosphorylation of Tyr15-Cdk5 by acting through the D2 class dopamine receptors. Moreover, in the 1-methyl-4-phenyl-1,2,4,6-tetrahydropyridine (MPTP) mouse model, dopamine deficiency caused increased phosphorylation of both Tyr15-Cdk5 and Thr75-DARPP-32 in the striatum, which could be attenuated by administration of L-3,4-dihydroxyphenylalanine and imatinib (STI-571), a selective c-Abl inhibitor. Our results suggest a functional link of Cdk5-pTyr15 with postsynaptic dopamine and glutamate signals through the c-Abl kinase activity in the striatum.

[Pathomechanisms of motor neuron death by mutant TFG]

Mutations in TFG gene have been demonstrated in hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P) and hereditary spastic paraplegia (HSP). A broad spectrum of TFG pathology is suspected in motor neuron diseases including amyotrophic lateral sclerosis (ALS). We performed mutation screening of TFG gene in ALS cases and evaluated the biological functions of mutant TFG by expression experiment in cultured cells. Two missense mutations associated with sporadic ALS were discovered. Mislocalization of ALS-related proteins, including TDP-43 and optineurin, was demonstrated. These results indicate that mistrafficking of ALS-related proteins by mutant TFG might be a biological cascade leading to motor neuron death.

Choroid plexus papilloma in a girl with hypomelanosis of Ito

The authors report a case of choroid plexus papilloma in a girl with hypomelanosis of Ito, and they review the literature in brief. Hypomelanosis of Ito is a rare neurocutaneous syndrome characterized by cutaneous hypopigmented whorls, streaks, and patches along lines of Blaschko. Most patients exhibit CNS manifestations, including psychomotor retardation, seizures, hypotonia, and ataxia. A 6-year-old girl with hypomelanosis of Ito was referred to the authors' hospital with bilateral tumors in the lateral ventricles. The right lateral ventricle tumor was surgically removed. Immunohistochemical investigations revealed the tumor to be a choroid plexus papilloma (WHO Grade I). A chromosomal investigation revealed that the tumor tissue demonstrated a large loss of heterozygosity at chromosome 10. The case reported here serves as a reminder that de novo brain tumors may arise in patients with chromosomal mosaicism.

The TRK-fused gene is mutated in hereditary motor and sensory neuropathy with proximal dominant involvement

Hereditary motor and sensory neuropathy with proximal dominant involvement (HMSN-P) is an autosomal-dominant neurodegenerative disorder characterized by widespread fasciculations, proximal-predominant muscle weakness, and atrophy followed by distal sensory involvement. To date, large families affected by HMSN-P have been reported from two different regions in Japan. Linkage and haplotype analyses of two previously reported families and two new families with the use of high-density SNP arrays further defined the minimum candidate region of 3.3 Mb in chromosomal region 3q12. Exome sequencing showed an identical c.854C>T (p.Pro285Leu) mutation in the TRK-fused gene (TFG) in the four families. Detailed haplotype analysis suggested two independent origins of the mutation. Pathological studies of an autopsied patient revealed TFG- and ubiquitin-immunopositive cytoplasmic inclusions in the spinal and cortical motor neurons. Fragmentation of the Golgi apparatus, a frequent finding in amyotrophic lateral sclerosis, was also observed in the motor neurons with inclusion bodies. Moreover, TAR DNA-binding protein 43 kDa (TDP-43)-positive cytoplasmic inclusions were also demonstrated. In cultured cells expressing mutant TFG, cytoplasmic aggregation of TDP-43 was demonstrated. These findings indicate that formation of TFG-containing cytoplasmic inclusions and concomitant mislocalization of TDP-43 underlie motor neuron degeneration in HMSN-P. Pathological overlap of proteinopathies involving TFG and TDP-43 highlights a new pathway leading to motor neuron degeneration.

Up-regulation of endogenous PML induced by a combination of interferon-beta and temozolomide enhances p73/YAP-mediated apoptosis in glioblastoma

Interferon-beta (IFN-β) is reported to augment anti-tumor effects by temozolomide in glioblastoma via down-regulation of MGMT. Promyelocytic leukemia (PML), a gene induced by IFN-β, is a tumor suppressor. Here, we report for the first time that in combination therapy, an IFN-β-induced increase in endogenous PML contributes to anti-tumor effects in p53 wild- and mutant glioma cells in a xenograft mice model. The increased PML promoted the accumulation of p73, a structural and functional homolog of p53, to fuse the coactivator Yes-associated-protein in the PML nuclear bodies. The adjuvant therapy targeted at PML may be a promising therapeutic strategy for glioblastoma.

Cell type-specific localization of optineurin in the striatal neurons of mice: implications for neuronal vulnerability in Huntington's disease

Striatal neuropathology of Huntington's disease (HD) involves primary and progressive degeneration of the medium-sized projection neurons, with relative sparing of the local circuit interneurons. The mechanism for such a patterned cell loss in the HD striatum continues to remain unclear. Optineurin (OPTN) is one of the proteins interacting with huntingtin and plays a protective role in several neurodegenerative disorders. To determine the cellular localization pattern of OPTN in the mouse striatum, we employed a highly sensitive immunohistochemistry with the tyramide signal amplification system. In this study, we show that OPTN appeared as a cytoplasmic protein within the subsets of the striatal neurons. Of particular interest was that OPTN was abundantly expressed in the interneurons, whereas low levels of OPTN were observed in the medium projection neurons. This cell type-specific distribution of OPTN in the striatum is strikingly complementary to the pattern of neuronal loss typically observed in the striatum of patients with HD. We suggest that OPTN abundance is an important cellular factor in considering the cell type-specific vulnerability of striatal neurons in HD.

Cyclin-dependent kinase 5 with phosphorylation of tyrosine 15 residue is enriched in striatal matrix compartment in adult mice

Accumulating evidence suggests that the striosome-matrix systems have a tight link with motor and behavioral brain functions and their disorders. Cyclin-dependent kinase 5 (Cdk5) is a versatile protein kinase that plays a role in synaptic functions and cell survival in adult brain, and its kinase activity is stimulated by phosphorylation at tyrosine 15 residue (pY15). In this study, we used an immunohistochemical method to show differential localization of Cdk5-pY15 in the striatal compartments of adult mice, with a heightened density of Cdk5-pY15 labeling in the matrix relative to the striosomes. Our findings indicate that Cdk5-pY15 can be a new marker for the striatal matrix compartment, and suggest a possible involvement of Cdk5-mediated signaling in compartment-specific neurotransmission and disease pathology in the striatum.

Identification and localization of a neuron-specific isoform of TAF1 in rat brain: implications for neuropathology of DYT3 dystonia

The neuron-specific isoform of the TAF1 gene (N-TAF1) is thought to be involved in the pathogenesis of DYT3 dystonia, which leads to progressive neurodegeneration in the striatum. To determine the expression pattern of N-TAF1 transcripts, we developed a specific monoclonal antibody against the N-TAF1 protein. Here we show that in the rat brain, N-TAF1 protein appears as a nuclear protein within subsets of neurons in multiple brain regions. Of particular interest is that in the striatum, the nuclei possessing N-TAF1 protein are largely within medium spiny neurons, and they are distributed preferentially, though not exclusively, in the striosome compartment. The compartmental preference and cell type-selective distribution of N-TAF1 protein in the striatum are strikingly similar to the patterns of neuronal loss in the striatum of DYT3 patients. Our findings suggest that the distribution of N-TAF1 protein could represent a key molecular characteristic contributing to the pattern of striatal degeneration in DYT3 dystonia.

Giant glioependymal cyst in an infant

The authors report the case of an infant with a giant glioependymal cyst. Although it has been suggested that these cysts originate from the tela choroidea, their origin remains controversial. This 35-month-old girl with truncal ataxia was referred to the authors' hospital. Magnetic resonance imaging revealed a giant cystic mass extending from the anterior to the posterior cranial fossa. Hydrocephalus was caused by obstruction of the sylvian aqueduct. Endoscopic fenestration of the cyst wall was performed. Histochemical and immunohistochemical staining identified the lesion as a glioependymal cyst. Magnetic resonance imaging performed 8 months later suggested that the cyst originated from the tela choroidea. At 5-year follow-up, there was no tumor recurrence and she had fully recovered. The origin of glioependymal cysts is discussed, and the authors suggest that their origin is the tela choroidea.

Hemichorea due to hemodynamic ischemia associated with extracranial carotid artery stenosis. Report of two cases

In this paper the authors describe two patients with recurrent hemiparesis and limb shaking that gradually progressed to hemichorea. Cerebral angiography confirmed severe unilateral internal carotid artery stenosis (95%) contralateral to the hemichorea. The cerebral blood flow, assessed using N-isopropyl-p-(iodine-123) iodoamphetamine single-photon emission computed tomography (SPECT), disclosed markedly decreased vascular reserves in both patients. After carotid endarterectomy was performed, the hemichorea gradually subsided and SPECT confirmed increased cerebral perfusion. The results in these cases indicate that surgical revascularization is effective for hemichorea due to cerebral ischemia with reduced vascular reserve.

Shear-stress effect on mitochondrial membrane potential and albumin uptake in cultured endothelial cells

Endothelial cells (ECs) that line the inner surface of blood vessels are continuously exposed to shear stress induced by blood flow in vivo, and shear stress affects ATP-dependent macromolecular transport in ECs. However, the relationship between the ATP production and shear stress is still unclear. We, therefore, evaluated mitochondrial ATP synthesis activity in cultured endothelial cells exposed to shear stress, using a confocal laser scanning microscope (CLSM) and a mitochondrial membrane potential probe (5,5',6,6'-tetrachloro-1,1',3, 3'-tetraethyl-benzimidazolycarbocyanine iodide, JC-1). Low shear stress (10 dyn/cm(2)) increased mitochondrial membrane potential by 30%. On the contrary, high shear stress (60 dyn/cm(2)) decreased it by 20%. This observation was consistent with the ATP-dependent albumin uptake into endothelial cells. Our results indicate that ATP synthetic activity is related to the albumin uptake into endothelial cells.