Akira Ito

Temporal profile of the vascular anatomy evaluated by 9.4-T magnetic resonance angiography and histopathological analysis in mice lacking RNF213: A susceptibility gene for moyamoya disease

Moyamoya disease (MMD) is a chronic occlusive cerebrovascular disease with unknown etiology. Recent genome-wide and locus-specific association studies identified RNF213 as an important MMD susceptibility gene. However, the exact mechanism by which an abnormality in RNF213 leads to MMD is unknown. To evaluate the role of RNF213 in the etiology of MMD, we generated RNF213-deficient mice (RNF213-/-) by deleting exon 32 of RNF213 by the Cre-lox system, and investigated whether they developed MMD. The temporal profile of cervical/intracranial arteries was evaluated by 9.4-T magnetic resonance angiography (MRA). The anatomy of the circle of Willis was analyzed by a trans-cardiac injection of carbon black dye. The common carotid arteries (CCA) were sectioned and the arterial wall thickness/thinness was evaluated by Elastica-Masson staining before and after CCA ligation, which selectively induced vascular hyperplasia. As a result, RNF213-/- grew normally, and no significant difference was observed in MRA findings, the anatomy of the circle of Willis, or vascular wall thickness/thinness between RNF-/- and wild-type littermates (Wt.) under normal conditions until 64 weeks of age. However, Elastica-Masson staining demonstrated that both the intima and medial layer were significantly thinner after CCA ligation in RNF213-/- than in Wt. after 14 days (P<0.01). In conclusion, mice lacking the RNF213 gene did not spontaneously develop MMD, indicating that a functional loss of RNF213 did not sufficiently induce MMD. Suppression of vascular remodeling in RNF213-/- requires further examination to clarify the role of RNF213.

Enhanced post-ischemic angiogenesis in mice lacking RNF213; a susceptibility gene for moyamoya disease.

Moyamoya disease (MMD) is a chronic occlusive cerebrovascular disease with unknown etiology that is characterized by the development of abnormal vascular networks at the base of the brain. Recent genome-wide studies identified RNF213 as an important MMD susceptibility gene. However, the exact mechanism by which the RNF213 abnormality leads to MMD remains unknown. Thus, we sought to clarify the role of RNF213 in angiogenesis under ischemic conditions using conventional RNF213 knockout mice. We assessed the infarction volume, cerebral edema, and vascular density in the ischemic brain after transient middle cerebral artery occlusion (tMCAO). To further evaluate systemic angiogenesis following chronic ischemia, we investigated blood flow recovery using laser speckle flowmetry, the severity of ambulatory impairments, and vascular density in the hind-limb after permanent femoral artery ligation. Results were compared between homozygous RNF213 knockout mice (RNF213 -/-) and wild-type littermates (Wt). No significant differences were observed in infarction volume or the formation of edema following tMCAO, or in vascular density 28 days after tMCAO between RNF213 -/- and Wt. Blood flow recovery was significantly improved in RNF213 -/- from 3 to 28 days after femoral artery ligation, and angiogenesis as shown by vascular density in the hind-limb was significantly enhanced in RNF213 -/- at 28 days. The amelioration of ambulatory impairments was also evident in RNF213 -/-. Angiogenesis was enhanced in mice lacking RNF213 after chronic hind-limb ischemia, which suggested the potential role of the RNF213 abnormality in the development of pathological vascular networks in chronic ischemia.

Temporal profile of the vascular anatomy evaluated by 9.4-tesla magnetic resonance angiography and histological analysis in mice with the R4859K mutation of RNF213, the susceptibility gene for moyamoya disease.

Moyamoya disease (MMD) is a chronic, occlusive cerebrovascular disease with an unknown etiology. Recent genome-wide and locus-specific association studies identified the RNF213 gene (RNF213) as an important susceptibility gene of MMD among East Asian populations; however, the mechanism by which an abnormality in RNF213 leads to MMD has not yet been elucidated. Therefore, we herein generated Rnf213-knock-in mice (RNF213-KI) expressing a missense mutation in mouse Rnf213, p. R4828K, on Exon 61, corresponding to human RNF213, p. R4859K, on Exon 60, in MMD patients, and investigated whether they developed MMD. We assessed the temporal profile of intracranial arteries by 9.4-T magnetic resonance angiography (MRA) continuously in the same mouse up to 64 weeks of age. The ratios of the outer diameter of the internal carotid artery (ICA)/basilar artery (BA) and middle cerebral artery (MCA)/BA were evaluated histopathologically. The common carotid arteries (CCA) were sectioned and arterial wall thickness/thinness was evaluated by Elastica-Masson staining before and after CCA ligation, which selectively induced vascular hyperplasia. The results obtained showed that RNF213-KI grew normally, with no significant difference being observed in MRA findings or the anatomy of the circle of Willis between homozygous RNF213-KI and wild-type (Wt) littermates. Furthermore, no significant difference was noted in the diameter of the intracranial vasculature (ICA/BA; p=0.82, MCA/BA; p=0.27) or in vascular remodeling after CCA ligation. Therefore, RNF213-KI did not spontaneously develop MMD. Multiple secondary insults such as environmental factors may contribute to the onset of MMD in addition to genetic factors.

SMTP-7, a new thrombolytic agent, decreases hemorrhagic transformation after transient middle cerebral artery occlusion under warfarin anticoagulation in mice

Stachybotrys microspora triprenyl phenol-7 (SMTP-7) is a new thrombolytic agent that exhibits anti-inflammatory effects. We previously demonstrated that the hemorrhagic transformation was fewer with SMTP-7 than with recombinant tissue plasminogen activator (rt-PA) following ischemia-reperfusion in animal models. We hypothesized that SMTP-7 may decrease hemorrhagic transformation after ischemia-reperfusion under the warfarin-treated condition. Transient middle cerebral artery occlusion (MCAO) was induced for 3h using an intraluminal suture in warfarin-treated mice to produce hemorrhagic transformation. Warfarin was administered orally for a 24-h feeding period before MCAO through bottled drinking water (5mg in 375 ml tap water), resulting in a mean INR of 5.6±0.2. Mice were treated with vehicle, rt-PA, or SMTP-7 5h before reperfusion. Twenty percent of vehicle-treated and 50.0% of rt-PA-treated mice died 24h after reperfusion, while all SMTP-7-treated mice survived. Hemorrhagic severity in SMTP-7-treated mice was significantly lower than that in rt-PA-treated mice. Neurological deficit was significantly lower in SMTP-7-treated mice than vehicle- and rt-PA-treated mice. These results indicate that SMTP-7 decreases mortality, hemorrhagic transformation, and neurological deficits, and can be a safe thrombolytic agent following MCAO under the warfarin-treated condition.

Temporal profile of magnetic resonance angiography and decreased ratio of regulatory T cells after immunological adjuvant administration to mice lacking RNF213, a susceptibility gene for moyamoya disease

Moyamoya disease (MMD) is a chronic, occlusive cerebrovascular disease with an unknown etiology and is characterized by an abnormal vascular network at the base of the brain. Recent studies identified the RNF213 gene (RNF213) as an important susceptibility gene for MMD; however, the mechanisms underlying the RNF213 abnormality related to MMD have not yet been elucidated. We previously reported that Rnf213-deficient mice and Rnf213 p. R4828K knock-in mice did not spontaneously develop MMD, indicating the importance of secondary insults in addition to genetic factors in the pathogenesis of MMD. The most influential secondary insult is considered to be an immunological reaction because RNF213 is predominantly expressed in immunological tissues. Therefore, we herein attempted to evaluate the role of an immunological stimulation as a supplementary insult to the target disruption of RNF213 in the pathophysiology of MMD. Rnf213-deficient mice were treated with strong immunological adjuvants including muramyl dipeptide (MDP)-Lys (L18), and then underwent time-sequential magnetic resonance angiography (MRA) up to 40 weeks of age. The results obtained did not reveal any characteristic finding of MMD, and no significant difference was observed in MRA findings or the anatomy of the circle of Willis between Rnf213-deficient mice and wild-type mice after the administration of MDP-Lys (L18). The ratio of regulatory T cells after the administration of MDP-Lys (L18) was significantly decreased in Rnf213-deficient mice (p<0.01), suggesting the potential role of the RNF213 abnormality in the differentiation of regulatory T cells. Although the mechanisms underlying the development of MMD currently remain unclear, the RNF213 abnormality may compromise immunological self-tolerance, thereby contributing to the development of MMD.

Use of Indocyanine Green Fluorescence Endoscopy to Treat Concurrent Perimedullary and Dural Arteriovenous Fistulas in the Cervical Spine

BACKGROUNDnIntraoperative microscopic fluorescence angiography using indocyanine green (ICG) provides visual information on real-time blood flow. However, this method cannot be applied for lesions that are not visible under microscopic imaging because excitation light does not reach the targeted vascular structures. Endoscope-integrated ICG video-angiography has recently been advocated to compensate for this limitation. This is the first reported case of a spinal arteriovenous malformation in which endoscope-integrated ICG video-angiography was successfully used.nnnCASE DESCRIPTIONnWe report the case of a 63-year-old man who presented with a subarachnoid hemorrhage from a spinal arteriovenous malformation at the C3 level. We chose the direct surgery option with a posterior approach to treat this lesion. Although the preoperative diagnosis was a perimedullary arteriovenous fistula (AVF) with multiple feeders, we found concurrent dural AVF and perimedullary AVFs during surgery. We introduced an endoscope and performed endoscope-integrated ICG video-angiography because it was difficult to identify the angioarchitectures of the perimedural and dural AVFs on the ventral surface of the spinal cord under microscopic view alone. Endoscope-integrated ICG video-angiography gave us clear and magnified angioarchitectures of these lesions. The fistulous point and the varix of the perimedullary AVF was coagulated and dissected under endoscopic view, and the draining vein of the dural AVF was also coagulated and dissected at the origin from the dura mater under microscopic view.nnnCONCLUSIONSnA posterior approach with the assistance of an endoscope and endoscope-integrated ICG video-angiography is feasible for spinal vascular diseases located ventrally.

Malignant pediatric brain tumor of primitive small round cell proliferation with bland-looking mesenchymal spindle cell elements

It is often difficult to classify rare malignant pediatric mixed brain tumors composed of mesenchymal elements. A 6-year-old boy presented to our hospital with a left frontal massive tumor manifesting as complaints of rapidly progressive right hemiparesis and motor aphasia over 2xa0weeks. Computed tomography showed a left frontal mass with thick calcification. Magnetic resonance imaging revealed an enhanced lesion with perifocal edema and mass effect. Total removal of the tumor was performed. Histological examination of the resected tumor revealed an anaplastic malignant small round cell component with a bland-looking mesenchymal spindle cell component. The patient was treated with irradiation to the whole craniospinal axis and a boost to the tumor bed, followed by chemotherapy consisting of ifosfamide, cisplatin, and etoposide, resulting in good control without local recurrence or metastasis at 2xa0years. A combined malignant tumor composed of ectodermal and mesenchymal components is generally named malignant ectomesenchymoma (MEM). The more malignant part of MEM is the mesenchymal component in most cases. In the present case, the more malignant component was not the mesenchymal component, but the small round cells.

Substitution effect in Ln1.85Ce0.15CuO4(Ln=Pr and Sm)

Abstract In the n-type superconductor Ln 1.85 Ce 0.15 CuO 4 (Ln=Pr, Sm), substitution effects of La for Ln was studied. We could prepare the samples Ln 1.85−x La x Ce 0.15 CuO 4 with a single phase of T′-type structure in the La concentration range of 0≦x≦1.2 for both Pr and Sm systems. The lattice parameters a and c together increase with x for both systems. While it is concluded that the number of the carriers keeps constant from oxygen content and paramagnetic susceptibility measurements, T c is gradually suppressed by La substitution. These results may indicate that the suppression of T c is not caused by the change of the carrier number or magnetic effect, but by some disorder effect.

A Study on 2D Photo-Realistic Facial Animation Generation Using 3D Facial Feature Points and Deep Neural Networks

This paper proposes a technique for generating a 2D photo-realistic facial animation from an input text. The technique is based on the mapping from 3D facial feature points with deep neural networks (DNNs). Our previous approach was based only on a 2D space using hidden Markov models (HMMs) and DNNs. However, this approach has a disadvantage that generated 2D facial pixels are sensitive to the rotation of the face in the training data. In this study, we alleviate the problem using 3D facial feature points obtained by Kinect. The information of the face shape and color is parameterized by the 3D facial feature points. The relation between the labels from texts and face-model parameters are modeled by DNNs in the model training. As a preliminary experiment, we show that the proposed technique can generate the 2D facial animation from arbitrary input texts.

Superconductivity of Ln1.85−xLaxCe0.15CuO4 (Ln=Pr,Sm)

Superconducting properties of the N-type superconductors Ln1.85−xLaxCe0.15CuO4 (L=Pr and Sm) have been studied. Sintered samples were prepared by solid state reaction. It is possible to synthesize the samples with single phase of the Nd2CuO4 type structure in wide concentration ranges 0≤x≤1.2 for Pr-based system and 0≤x≤0.5 for Sm-based one. The lattice parameters a and c increase monotonically with increasing x for both systems. While it is expected that the substitution of Pr or Sm atoms by La does not change the carrier concentration of these systems because the oxygen content 4−y is kept almost constant. The superconducting transition temperature Tc decreases with increasing La-concentration x. The suppression of Tc is more rapid for Sm-based system than for Pr-based one. The x dependence of Tc for both systems could be scaled by the reduced lattice parameter (a−a0)/a0.