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24 result(s) for "Imaizumi, Toshio"
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Xenotransplantation of transgenic pig olfactory ensheathing cells promotes axonal regeneration in rat spinal cord
Here we describe transplantation of olfactory ensheathing cells (OECs) or Schwann cells derived from transgenic pigs expressing the human complement inhibitory protein, CD59 (hCD59), into transected dorsal column lesions of the spinal cord of the immunosuppressed rat to induce axonal regeneration. Non-transplanted lesion-controlled rats exhibited no impulse conduction across the transection site, whereas in animals receiving transgenic pig OECs or Schwann cells impulse conduction was restored across and beyond the lesion site for more than a centimeter. Cell labeling indicated that the donor cells migrated into the denervated host tract. Conduction velocity measurements showed that the regenerated axons conducted impulses faster than normal axons. By morphological analysis, the axons seemed thickly myelinated with a peripheral pattern of myelin expected from the donor cell type. These results indicate that xenotranplantation of myelin-forming cells from pigs genetically altered to reduce the hyperacute response in humans are able to induce elongative axonal regeneration and remyelination and restore impulse conduction across the transected spinal cord.
Sex Differences in Frequency, Severity, and Distribution of Cerebral Microbleeds
Cerebral small vessel disease (SVD) is associated with various cerebrovascular outcomes, but data on sex differences in SVD are scarce. To investigate whether the frequency, severity, and distribution of cerebral microbleeds (CMB), other SVD markers on magnetic resonance imaging (MRI), and outcomes differ by sex. This cohort study used pooled individual patient data from the Microbleeds International Collaborative Network, including patients from 38 prospective cohort studies in 18 countries between 2000 and 2018, with clinical follow-up of at least 3 months (up to 5 years). Participants included patients with acute ischemic stroke or transient ischemic attack with available brain MRI. Data were analyzed from April to December 2023. Outcomes of interest were presence of CMB, lacunes, and severe white matter hyperintensities determined on MRI. Additionally, mortality, recurrent ischemic stroke, and intracranial hemorrhage during follow-up were assessed. Multivariable random-effects logistic regression models, Cox regression, and competing risk regression models were used to investigate sex differences in individual SVD markers, risk of recurrent cerebrovascular events, and death. A total of 20 314 patients (mean [SD] age, 70.1 [12.7] years; 11 721 [57.7%] male) were included, of whom 5649 (27.8%) had CMB. CMB were more frequent in male patients, and this was consistent throughout different age groups, locations, and in multivariable models (female vs male adjusted odds ratio [aOR], 0.86; 95% CI, 0.80-0.92; P < .001). Female patients had fewer lacunes (aOR, 0.82; 95% CI, 0.74-0.90; P < .001) but a higher prevalence of severe white matter hyperintensities (aOR, 1.10; 95% CI, 1.01-1.20; P = .04) compared with male patients. A total of 2419 patients (11.9%) died during a median (IQR) follow-up of 1.4 (0.7-2.5) years. CMB presence was associated with a higher risk of mortality in female patients (hazard ratio, 1.15; 95% CI, 1.02-1.31), but not male patients (hazard ratio, 0.95; 95% CI, 0.84-1.07) (P for interaction = .01). A total of 1113 patients (5.5%) had recurrent ischemic stroke, and 189 patients (0.9%) had recurrent intracranial hemorrhage, with no sex differences. This cohort study using pooled individual patient data found varying frequencies of individual SVD markers between female and male patients, indicating potential pathophysiological differences in manifestation and severity of SVD. Further research addressing differences in pathomechanisms and outcomes of SVD between female and male patients is required.
Subarachnoid hemosiderin deposition after subarachnoid hemorrhage on T2-weighted MRI correlates with the location of disturbed cerebrospinal fluid flow on computed tomography cisternography
A 72-year-old male was admitted with subarachnoid hemorrhage associated with a ruptured cerebral aneurysm. The aneurysm was treated with clipping soon after radiological examination. Eight weeks after the treatment, the patient suffered from secondary hydrocephalus resulting from blockage of the subarachnoid space due to subarachnoid granulation. Previous pathological examination revealed the granulation was associated with hemosiderin deposition. We investigated subarachnoid hemosiderin deposition in this patient using T2*-weighted (T2*-w) magnetic resonance image (MRI), a sensitive method for hemosiderin detection. computed tomography (CT) cisternography demonstrated that cerebrospinal fluid (CSF) flow was disturbed adjacent to sites of subarachnoid hemosiderin deposition on T2*-w MRI. Placement of a ventriculo-peritoneal shunt contributed to neurological improvement. In this case, T2*-w MRI was an effective means of diagnosing the location of disturbed CSF flow associated with subarachnoid hemosiderin deposition.
Subarachnoid hemosiderin deposition after subarachnoid hemorrhage on T2FNx01-weighted MRI correlates with the location of disturbed cerebrospinal fluid flow on computed tomography cisternography
A 72-year-old male was admitted with subarachnoid hemorrhage associated with a ruptured cerebral aneurysm. The aneurysm was treated with clipping soon after radiological examination. Eight weeks after the treatment, the patient suffered from secondary hydrocephalus resulting from blockage of the subarachnoid space due to subarachnoid granulation. Previous pathological examination revealed the granulation was associated with hemosiderin deposition. We investigated subarachnoid hemosiderin deposition in this patient using T2FNx01-weighted (T2FNx01-w) magnetic resonance image (MRI), a sensitive method for hemosiderin detection. computed tomography (CT) cisternography demonstrated that cerebrospinal fluid (CSF) flow was disturbed adjacent to sites of subarachnoid hemosiderin deposition on T2FNx01-w MRI. Placement of a ventriculo-peritoneal shunt contributed to neurological improvement. In this case, T2FNx01-w MRI was an effective means of diagnosing the location of disturbed CSF flow associated with subarachnoid hemosiderin deposition.
Genetic determinants of risk in autoimmune pulmonary alveolar proteinosis
Pulmonary alveolar proteinosis (PAP) is a devastating lung disease caused by abnormal surfactant homeostasis, with a prevalence of 6–7 cases per million population worldwide. While mutations causing hereditary PAP have been reported, the genetic basis contributing to autoimmune PAP (aPAP) has not been thoroughly investigated. Here, we conducted a genome-wide association study of aPAP in 198 patients and 395 control participants of Japanese ancestry. The common genetic variant, rs138024423 at 6p21, in the major-histocompatibility-complex (MHC) region was significantly associated with disease risk (Odds ratio [OR] = 5.2; P  = 2.4 × 10 −12 ). HLA fine-mapping revealed that the common HLA class II allele, HLA-DRB1*08:03, strongly drove this signal (OR = 4.8; P  = 4.8 × 10 −12 ), followed by an additional independent risk allele at HLA-DPβ1 amino acid position 8 (OR = 0.28; P  = 3.4 × 10 −7 ). HLA-DRB1*08:03 was also associated with an increased level of anti-GM-CSF antibody, a key driver of the disease (β = 0.32; P  = 0.035). Our study demonstrated a heritable component of aPAP, suggesting an underlying genetic predisposition toward an abnormal antibody production. Autoimmune pulmonary alveolar proteinosis (aPAP) is a complex lung disease caused by abnormal surfactant homeostasis. Here, the authors carry out a genome-wide association study of aPAP in a Japanese cohort, finding variants in the MHC and suggesting predisposition to abnormal antibody production.
The diabetes-susceptible gene SLC30A8/ZnT8 regulates hepatic insulin clearance
Recent genome-wide association studies demonstrated that common variants of solute carrier family 30 member 8 gene (SLC30A8) increase susceptibility to type 2 diabetes. SLC30A8 encodes zinc transporter-8 (ZnT8), which delivers zinc ion from the cytoplasm into insulin granules. Although it is well known that insulin granules contain high amounts of zinc, the physiological role of secreted zinc remains elusive. In this study, we generated mice with β cell-specific Slc30a8 deficiency (ZnT8KO mice) and demonstrated an unexpected functional linkage between Slc30a8 deletion and hepatic insulin clearance. The ZnT8KO mice had low peripheral blood insulin levels, despite insulin hypersecretion from pancreatic β cells. We also demonstrated that a substantial amount of the hypersecreted insulin was degraded during its first passage through the liver. Consistent with these findings, ZnT8KO mice and human individuals carrying rs13266634, a major risk allele of SLC30A8, exhibited increased insulin clearance, as assessed by c-peptide/insulin ratio. Furthermore, we demonstrated that zinc secreted in concert with insulin suppressed hepatic insulin clearance by inhibiting clathrin-dependent insulin endocytosis. Our results indicate that SLC30A8 regulates hepatic insulin clearance and that genetic dysregulation of this system may play a role in the pathogenesis of type 2 diabetes.
Characterization of AtSTOP1 Orthologous Genes in Tobacco and Other Plant Species
Aluminum (Al) and proton (H + ) tolerances are essential traits for plants to adapt to acid soil environments. In Arabidopsis (Arabidopsis thaliana), these tolerances are mediated by a zinc-finger transcription factor, SENSITIVE TO PROTON RHIZOTOXICITY1 (AtSTOP1), which regulates the transcription of multiple genes critical for tolerance to both stressors. Here, the functions of orthologous proteins (STOP1-like proteins) in other plant species were characterized by reverse genetics analyses and in planta complementation assays. RNA interference of a gene for NtSTOP1 repressed Al and H+ tolerances of tobacco (Nicotiana tabacum) roots. Tobacco roots released citrate in response to Al, concomitant with the up-regulated transcription of an ortholog of an Al tolerance gene encoding a citrate-transporting multidrug and toxic compound extrusion protein. The RNA interference repression of NtSTOP1 blocked this process and also repressed the transcription of another orthologous gene for Al tolerance, ALUMINUM SENSITIVE3, which encodes a prokaryote-type transporter. These results demonstrated that NtSTOP1 regulates Al tolerance in tobacco through the transcriptional regulation of these genes. The in planta complementation assays revealed that other plant species, including woody plants, a legume, and a moss (Physcomitrella patens), possess functional STOP1-like proteins that can activate several H+ and Al-tolerance genes in Arabidopsis. Knocking out the gene encoding the STOP1-like protein decreased the Al tolerance of P. patens. Together, our results strongly suggest that transcriptional regulation by STOP1-like proteins is evolutionarily conserved among land plants and that it confers the ability to survive in acid soils through the transcriptional regulation of Al- and H + -tolerance genes.
Deficiency of MicroRNA-23-27-24 Clusters Exhibits the Impairment of Myelination in the Central Nervous System
Several microRNAs (miRNAs), including miR-23 and miR-27a have been reportedly involved in regulating myelination in the central nervous system. Although miR-23 and miR-27a form clusters in vivo and the clustered miRNAs are known to perform complementary functions, the role of these miRNA clusters in myelination has not been studied. To investigate the role of miR-23-27-24 clusters in myelination, we generated miR-23-27-24 cluster knockout mice and evaluated myelination in the brain and spinal cord. Our results showed that 10-week-old knockout mice had reduced motor function in the hanging wire test compared to the wild-type mice. At 4 weeks, 10 weeks, and 12 months of age, knockout mice showed reduced myelination compared to wild-type mice. The expression levels of myelin basic protein and myelin proteolipid protein were also significantly lower in the knockout mice compared to the wild-type mice. Although differentiation of oligodendrocyte progenitor cells to oligodendrocytes was not inhibited in the knockout mice, the percentage of oligodendrocytes expressing myelin basic protein was significantly lower in 4-week-old knockout mice than that in wild-type mice. Proteome analysis and western blotting showed increased expression of leucine-zipper-like transcription regulator 1 (LZTR1) and decreased expression of R-RAS and phosphorylated extracellular signal-regulated kinase 1/2 (pERK1/2) in the knockout mice. In summary, loss of miR-23-27-24 clusters reduces myelination and compromises motor functions in mice. Further, LZTR1, which regulates R-RAS upstream of the ERK1/2 pathway, a signal that promotes myelination, has been identified as a novel target of the miR-23-27-24 cluster in this study.
Treatment-associated outcomes of patients with primary ocular adnexal MALT lymphoma after accurate diagnosis
BackgroundDifferentiation between primary ocular adnexal mucosa-associated lymphoid tissue (POA-MALT) lymphoma and reactive lymphoid hyperplasias sometimes may be difficult. We have examined the treatment-associated mortality of POA-MALT lymphoma after confirmed diagnosis and evaluated their proper treatments.Patients and methodsFrom 1991 through 2016, cases of POA-MALT lymphoma were retrospectively analyzed based on their pathological and molecular/immunological diagnoses.ResultsA total of 78 cases with POA-MALT lymphoma with a median age of 66 years were analyzed over median/mean observations of 6.4/7.1 years. Forty-four patients (56%) were diagnosed with IgH gene clonality and 10 patients (13%) were diagnosed with flow cytometric analysis in addition to the pathological decision. The rest (24 patients, 31%) were diagnosed employing pathological decisions of hemato-pathologists and clinical decisions. All patients, except cases of watchful waiting, achieved complete remission. After initial treatment, 68 patients (87%) presented disease-free during the observation period. As treatment, a radiotherapy-based strategy was followed with 15 patients (19%, group A). Immuno-chemotherapy was administered to 24 patients (31%, B). Surgical extraction only was selected for 36 patients (46%, C). Watchful waiting was selected with three patients (4%). Recurrence after the initial treatment was found in one patient (7%) out of A, in three patients (13%) out of B, and in six patients (17%) out of C, respectively. Progression-free survivals at 5 and 10 years were 100 and 100% in A, 95 and 75% in B, and 88 and 81% in C, respectively. The recurrence rates between the patients who were diagnosed with only pathological decision (n = 24) and the patients who were diagnosed with molecular and immunological procedures (n = 54) did not show any statistical differences.ConclusionOur results indicate that radiotherapy-based treatment strategies for patients with POA-MALT lymphoma show a low rate of recurrence and may improve their prognosis even after the accurate diagnosis. However, contamination of the cases with reactive (polyclonal) lymphoid hyperplasia into those with MALT lymphoma should be carefully removed to avoid unnecessary treatment for malignancies that do not exist.