Far-East Asian Toxoplasma isolates share ancestry with North and South/Central American recombinant lineages.

Toxoplasma gondii is a global protozoan pathogen. Clonal lineages predominate in Europe, North America, Africa, and China, whereas highly recombinant parasites are endemic in South/Central America. Far East Asian T. gondii isolates are not included in current global population genetic structure analyses at WGS resolution. Here we report a genome-wide population study that compared eight Japanese and two Chinese isolates against representative worldwide T. gondii genomes using POPSICLE, a novel population structure analyzing software. Also included were 7 genomes resurrected from non-viable isolates by target enrichment sequencing. Visualization of the genome structure by POPSICLE shows a mixture of Chinese haplogroup (HG) 13 haploblocks introgressed within the genomes of Japanese HG2 and North American HG12. Furthermore, two ancestral lineages were identified in the Japanese strains; one lineage shares a common ancestor with HG11 found in both Japanese strains and North American HG12. The other ancestral lineage, found in T. gondii isolates from a small island in Japan, is admixed with genetically diversified South/Central American strains. Taken together, this study suggests multiple ancestral links between Far East Asian and American T. gondii strains and provides insight into the transmission history of this cosmopolitan organism.

Proton Pump Inhibitors and Cyclin-Dependent Kinase 4/6 Inhibitors in Patients With Breast Cancer.

BACKGROUND: Proton pump inhibitors (PPIs) reduce the bioavailability of several anticancer drugs. The impact of PPIs co-administered with cyclin-dependent kinase 4 and 6 inhibitors is controversial. We aimed to clarify whether the concomitant use of PPIs impacts palbociclib and abemaciclib effectiveness in breast cancer treatment. PATIENTS AND METHODS: This multicenter, retrospective, observational study, conducted across 4 medical institutions in Japan, consecutively included patients with endocrine-resistant metastatic breast cancer, receiving palbociclib or abemaciclib between December 2017 and August 2022. Propensity score-matched analyses were performed. Treatment efficacy and safety with and without PPIs were compared. Progression-free survival and overall survival were estimated using the Kaplan-Meier method and compared using a log-rank test. A Cox proportional hazards model was used to estimate the hazard ratio. RESULTS: The study included 240 patients. After 1:1 matching, 112 patients were treated with and without PPIs. The median progression-free survival period was 1.2 years in the PPI group and 1.3 years in the non-PPI group (hazard ratio, 1.19; 95% CI, 0.70-2.02). The median overall survival period was 3.6 years in the PPI group, whereas it was not reached in the non-PPI group (hazard ratio, 1.23; 95% CI, 0.61-2.47). Consistent results were obtained for subgroups receiving palbociclib (n = 177) and abemaciclib (n = 63) without propensity score matching. Adverse event incidence and severity were similar in both groups. CONCLUSION: The effectiveness of cyclin-dependent kinase 4/6 inhibitors is unlikely to be affected by concomitant PPI use. Future prospective pharmacokinetic studies are warranted.

Surveillance of antimicrobial-resistant Escherichia coli in Sheltered dogs in the Kanto Region of Japan.

There is a lack of an established antimicrobial resistance (AMR) surveillance system in animal welfare centers. Therefore, the AMR prevalence in shelter dogs is rarely known. Herein, we conducted a survey in animal shelters in Chiba and Kanagawa prefectures, in the Kanto Region, Japan, to ascertain the AMR status of Escherichia coli  (E. coli) prevalent in shelter dogs. E. coli was detected in the fecal samples of all 61 and 77 shelter dogs tested in Chiba and Kanagawa, respectively. The AMR was tested against 20 antibiotics. E. coli isolates derived from 16.4% and 26.0% of samples from Chiba and Kanagawa exhibited resistance to at least one antibiotic, respectively. E. coli in samples from Chiba and Kanagawa prefectures were commonly resistant to ampicillin, piperacillin, streptomycin, kanamycin, tetracycline, and nalidixic acid; that from the Kanagawa Prefecture to cefazolin, cefotaxime, aztreonam, ciprofloxacin, and levofloxacin and that from Chiba Prefecture to chloramphenicol and imipenem. Multidrug-resistant bacteria were detected in 18 dogs from both regions; ß-lactamase genes (blaTEM, blaDHA-1, blaCTX-M-9 group CTX-M-14), quinolone-resistance protein genes (qnrB and qnrS), and mutations in quinolone-resistance-determining regions (gyrA and parC) were detected. These results could partially represent the AMR data in shelter dogs in the Kanto Region of Japan.

Acceleration of opportunistic atrial fibrillation screening for elderly patients in routine primary care.

Cardio-embolic ischemic stroke caused by atrial fibrillation is more severe compared with other types of stroke, such as lacunar infarction and atherothrombotic infarction in patients without atrial fibrillation. Therefore, it is important to prevent cardio-embolic ischemic stroke by detecting atrial fibrillation early in at-risk patients and administering appropriate anticoagulation therapy. This prospective observational study aimed to evaluate the effectiveness of opportunistic atrial fibrillation screening at 12 primary clinics in Japan. The study included a 12-month pre-campaign period and a 12-month campaign period. During the campaign period, an awareness campaign was conducted to encourage physicians to be mindful of screening patients aged ≥65 years for atrial fibrillation by checking their pulses and performing subsequent electrocardiography when an irregular pulse was detected. The primary outcome was the proportion of patients with newly diagnosed atrial fibrillation. A sub-analysis focusing on first-time outpatients was performed. There were 9921 and 10,282 patients with no history of atrial fibrillation in the pre-campaign and campaign periods, respectively. In the whole population, the proportion of patients with newly diagnosed atrial fibrillation was 0.9% throughout the pre-campaign and campaign periods. In the sub-analysis limited to first-time outpatients, the detection proportion increased from 1.6% to 1.9% during the campaign period. In terms of age stratification, a large increase in detection was observed, especially among patients aged 65-74 years (detection increased from 0.9% to 1.5%) and ≥85 years (detection increased from 2.9% to 3.3%) during the campaign period. Our findings suggest the feasibility of opportunistic atrial fibrillation screening in routine primary care practice in Japan. Of note, our findings suggest that opportunistic atrial fibrillation screening targeting first-time outpatients may be of clinical value.

Comparison of hospital length of stay of acute ischemic stroke patients with non-valvular atrial fibrillation started on rivaroxaban or warfarin treatment during hospitalization.

OBJECTIVE: To compare the hospital length of stay (LOS) between rivaroxaban and warfarin in hospitalized acute stroke patients with non-valvular atrial fibrillation (NVAF) in Japan. METHODS: This was a retrospective, observational study using a Japanese hospital claims database. Data of NVAF patients who were started on oral anticoagulant (OAC) treatment during hospitalization were extracted and LOS-OAC (period from the initiation of index OAC therapy to the end of hospitalization or censoring date) and medical costs were compared between rivaroxaban and warfarin treatments. To compare LOS-OAC, a time-to-event analysis was performed using the Kaplan-Meier method. The analysis period was from April 2012 to December 2015. RESULTS: This study included 773 rivaroxaban users and 1077 warfarin users. After the propensity score matching, 546 patients for each treatment constituted the matched cohorts. Although the rivaroxaban users had a similar LOS-OAC to warfarin users (median, 18 vs. 19 days, p = .657) in the matched cohorts, 3 days shorter LOS-OAC was observed in the rivaroxaban users (median, 17 vs. 20 days, p = .043) after IPTW adjustment. Subgroup analysis by the severity of stroke after IPTW adjustment demonstrated that rivaroxaban users had a shorter LOS-OAC than warfarin users among patients with mild (median, 10 vs. 14 days) and moderate stroke severity (22 vs. 27 days), but not among those with severe stroke severity (26 vs. 25 days). LIMITATIONS: It is not possible to say that the only confounder was stroke severity and therefore other possible known and unknown confounders could not be ruled out. CONCLUSIONS: The rivaroxaban users had a 3-day shorter LOS-OAC after IPTW-adjustment. Using rivaroxaban was associated with 4-5 days shorter LOS-OAC than using warfarin in patients with mild or moderate stroke, though treatment selection did not have a large impact in patients with severe stroke.

Effects of Sedation by Intramuscular Administration of Medetomidine on Canine Abdominal Vascular System and Hepatic Parenchyma Imaging Using Enhancement Dynamic Computed Tomography.

This prospective crossover study compared the effects of intramuscular administration of medetomidine for sedation on parameters of the abdominal vascular system, measured by enhancement computed tomography (CT), to those of propofol-induced sevoflurane maintenance anesthesia, as a control, in five clinically healthy adult male beagle dogs (11.4-12.8 kg). Each animal underwent both protocols at a 1-week interval. The enhancement (HU) and time to peak enhancement on CT were measured for the aorta (AO), caudal vena cava (CVC), portal vein (PV), and hepatic parenchyma (HP). The contrast effects in the AO, PV, and HP were significantly delayed under medetomidine sedation compared to the control anesthesia protocol. Particularly, the contrast effect in the PV and HP was significantly delayed under sedation, appearing approximately 1 min after contrast medium injection. This delay likely reflects the peripheral vasoconstrictive effect of medetomidine. We noted a generally early high contrast enhancement of the CVC under medetomidine sedation, likely contributed by the induced bradycardia. Therefore, findings obtained on contrast enhancement CT under medetomidine sedation may be different from those obtained under propofol-induced sevoflurane maintenance anesthesia. These differences are important to consider when using the findings to inform diagnosis.

Combining non-contrast enhanced magnetic resonance thoracic ductography with vascular contrast-enhanced computed tomography to identify the canine thoracic duct.

Background: In humans, visualization of the thoracic duct by magnetic resonance imaging (MRI) has been attempted, and recent advances have enabled clinicians to visualize the thoracic duct configuration in a less invasive manner. Moreover, MRI does not require contrast media, and it enables visualization of morphological details of the thoracic structures. In veterinary practice, the thoracic duct has not been visualized three dimensionally in MRI. Aim: This study aimed to assess the performance of our magnetic resonance thoracic ductography (MRTD) technique to visualize the thoracic duct and the surrounding 3D anatomical structures by combining MRTD and vascular contrast-enhanced thoracic computed tomography (CT) images in dogs. Methods: Five adult male beagle dogs (11.4-12.8 kg) were included in this study. Sagittal and transverse T2-weighted images were scanned in MRI. Scanning in MRTD used a single-shot fast spin echo sequence with a respiratory gate. CT was performed after the intravenous injection of contrast medium. All MRTD and CT images were merged using a workstation. Results: The thoracic ducts were identified in MRTD images of all dogs, and the surrounding anatomical structures were located with the aid of contrast-enhanced thoracic CT. In all dogs, the thoracic ducts coursed along the right-dorsal side of the aorta, cranially from the L2 level. Thereafter, these bent to the left side at the aortic arch and curved at the left external jugular vein angle. A comparison of the number of thoracic ducts at each vertebra between transverse T2WI and MRTD did not reveal any significant differences for all vertebrae. Conclusion: The results from our study suggest that MRTD using the single-shot fast spin echo sequence could be a useful tool for visualization of the thoracic duct. Furthermore, the image merged from MRTD and vascular-enhanced images provided detailed anatomical annotation of the thorax. The MRTD protocol described in this study is safe and easily adaptable, without the need for contrast medium injection into the lymph system. In addition, the images fused from MRTD and vascular contrast-enhanced CT image of the thorax could provide detailed anatomical annotations for preoperative planning.

Impact of care coordination on oral anticoagulant therapy among patients with atrial fibrillation in routine clinical practice in Japan: a prospective, observational study.

BACKGROUND: Care coordination between general practitioners (GPs) and cardiovascular specialists is expected to play a key role in establishing appropriate oral anticoagulant (OAC) treatment in atrial fibrillation (AF) patients. The aim of this study was to assess the impact of care coordination on oral anticoagulant therapy in the management of AF in Japan. METHODS: This study was a multi-center, single-arm, prospective cohort study with retrospective chart and claims data review for historical controls. The study included three study periods: a 12-month pre-campaign period; a 12-month campaign period for AF screening and care coordination; and a 3-month post-campaign period for follow-up of care coordination. During the campaign period, patients aged ≥65 years who attended participating GP clinics underwent opportunistic AF screening by GPs under the campaign. At the discretion of the GP, newly diagnosed AF patients after the screening were referred to a cardiovascular specialist for care coordination. To assess the impact of care coordination and evaluate the effects of the campaign, implementation of care coordination, antithrombotic therapies, and patient-reported outcomes were compared between patients with and without care coordination, and between patients during the pre-campaign and campaign periods. RESULTS: There were 86 newly diagnosed AF patients during the pre-campaign period and 90 during the campaign period. The percentage of patients with care coordination increased from 3.5% (3/86) in the pre-campaign period to 14.4% (n = 13/90) during the campaign period. The percentage of patients who received OAC therapies, according to the definition from the Japanese AF medication guideline, increased from 55.8% (48/86) to 71.1% (64/90) during the campaign period regardless of care coordination. Younger patients were referred to cardiovascular specialists for care coordination. Implementation of OAC therapy did not differ between patients with and without care coordination. Adherence to OAC therapy was low regardless of care coordination. CONCLUSIONS: This GP-targeted campaign was effective at raising awareness regarding the implementation of care coordination and appropriate OAC therapy at local clinical practices in Japan. Improvement of adherence to OAC therapy in elderly patients is a critical issue, and measures such as education programs targeted to patients and healthcare professionals should be undertaken.

Tracking and clarifying differential traits of classical- and atypical L-type bovine spongiform encephalopathy prions after transmission from cattle to cynomolgus monkeys.

Classical- (C-) and atypical L-type bovine spongiform encephalopathy (BSE) prions cause different pathological phenotypes in cattle brains, and the disease-associated forms of each prion protein (PrPSc) has a dissimilar biochemical signature. Bovine C-BSE prions are the causative agent of variant Creutzfeldt-Jakob disease. To date, human infection with L-BSE prions has not been reported, but they can be transmitted experimentally from cows to cynomolgus monkeys (Macaca fascicularis), a non-human primate model. When transmitted to monkeys, C- and L-BSE prions induce different pathological phenotypes in the brain. However, when isolated from infected brains, the two prion proteins (PrPSc) have similar biochemical signatures (i.e., electrophoretic mobility, glycoforms, and resistance to proteinase K). Such similarities suggest the possibility that L-BSE prions alter their virulence to that of C-BSE prions during propagation in monkeys. To clarify this possibility, we conducted bioassays using inbred mice. C-BSE prions with or without propagation in monkeys were pathogenic to mice, and exhibited comparable incubation periods in secondary passage in mice. By contrast, L-BSE prions, either with or without propagation in monkeys, did not cause the disease in mice, indicating that the pathogenicity of L-BSE prions does not converge towards a C-BSE prion type in this primate model. These results suggest that, although C- and L-BSE prions propagated in cynomolgus monkeys exhibit similar biochemical PrPSc signatures and consist of the monkey amino acid sequence, the two prions maintain strain-specific conformations of PrPSc in which they encipher and retain unique pathogenic traits.

A designer molecular chaperone against transmissible spongiform encephalopathy slows disease progression in mice and macaques.

Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative diseases that lack therapeutic solutions. Here, we show that the molecular chaperone (N,N'-([cyclohexylmethylene]di-4,1-phenylene)bis(2-[1-pyrrolidinyl]acetamide)), designed via docking simulations, molecular dynamics simulations and quantum chemical calculations, slows down the progress of TSEs. In vitro, the designer molecular chaperone stabilizes the normal cellular prion protein, eradicates prions in infected cells, prevents the formation of drug-resistant strains and directly inhibits the interaction between prions and abnormal aggregates, as shown via real-time quaking-induced conversion and in vitro conversion NMR. Weekly intraperitoneal injection of the chaperone in prion-infected mice prolonged their survival, and weekly intravenous administration of the compound in macaques infected with bovine TSE slowed down the development of neurological and psychological symptoms and reduced the concentration of disease-associated biomarkers in the animals' cerebrospinal fluid. The de novo rational design of chaperone compounds could lead to therapeutics that can bind to different prion protein strains to ameliorate the pathology of TSEs.

Utilization of Anticoagulant and Antiplatelet Agents Among Patients With Atrial Fibrillation Undergoing Percutaneous Coronary Intervention　- Retrospective Cohort Study Using a Nationwide Claims Database in Japan.

BACKGROUND: The European Society of Cardiology recommends a risk-based antithrombotic strategy for patients with atrial fibrillation (AF) who undergo percutaneous coronary intervention (PCI) based on CHA2DS2-VASc and HAS-BLED scores. However, because it is unclear if that strategy can be generalized to Asians, we aimed to describe antithrombotic therapies among Japanese patients.Methods and Results:Using a nationwide claims database in Japan, this retrospective cohort study identified AF patients who underwent PCI from April 1, 2014 to March 31, 2015. The primary outcome was utilization of anticoagulant and antiplatelet agents before PCI, at discharge, and 6, 9, and 12 months after PCI. The secondary outcome was incidence of stroke after PCI. We identified 10,862 patients and 87.5% of them had high CHA2DS2-VASc and HAS-BLED scores. There were no significant differences in antithrombotic therapies across the risk strata. More than 30% of patients at high risk of thrombosis did not receive oral anticoagulant prescriptions at discharge. The hazard ratio of incidence of stroke in patients with prior stroke compared with patients without prior stroke was 9.09 (95% confidence interval 7.86-10.50, P<0.01). CONCLUSIONS: Among Japanese AF patients who underwent PCI, prescriptions for antiplatelet agents were more common than those for anticoagulant agents. The majority of study participants were classified as high risk, suggesting a need for a new risk classification that reflects the risk profiles of Japanese patients.

Persistent Expression of Dopamine-Synthesizing Enzymes 15 Years After Gene Transfer in a Primate Model of Parkinson's Disease.

Restoring dopamine production in the putamen through gene therapy is a straightforward strategy for ameliorating motor symptoms for Parkinson's disease (PD). In a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) toxicity-based primate model of PD, we previously showed the safety and efficacy of adeno-associated viral (AAV) vector-mediated gene delivery to the putamen of three dopamine-synthesizing enzymes (tyrosine hydroxylase [TH], aromatic l-amino acid decarboxylase [AADC], and guanosine triphosphate cyclohydrolase I [GCH]) up to 10 months postprocedure. Although three of four monkeys in this study have previously undergone postmortem analysis, one monkey was kept alive for 15 years after gene therapy to evaluate long-term effects. Here, we report that this monkey showed behavioral recovery in the right-side limb that remained unchanged for 15 years, at which time euthanasia was carried out owing to onset of senility. Immunohistochemistry of the postmortem brain from this monkey revealed persistent expression of TH, AADC, and GCH genes in the lesioned putamen. Transduced neurons were broadly distributed, with the estimated transduction region occupying 91% of the left postcommissural putamen. No signs of cytotoxicity or Lewy body pathology were observed in the AAV vector-injected putamen. This study provides evidence of long-term safety and efficacy of the triple-transduction method as a gene therapy for PD.

Analysis of Macular Drusen and Blood Test Results in 945 Macaca fascicularis.

Age-dependent formation of macular drusen caused by the focal accumulation of extracellular deposits beneath the retinal pigment epithelium precede the development of age-related macular degeneration (AMD), one of the leading causes of blindness worldwide. It is established that inflammation contributes to the pathogenesis of drusen and AMD. However, development of a preemptive therapeutic strategy targeting macular drusen and AMD has been impeded by the lack of relevant animal models because most laboratory animals lack macula, an anatomic feature present only in humans and a subset of monkeys. Reportedly, macular drusen and macular degeneration develop in monkeys in an age-dependent manner. In this study, we analyzed blood test results from 945 Macaca fascicularis, 317 with and 628 without drusen. First, a trend test for drusen frequency (the Cochran-Armitage test) was applied to the quartile data for each parameter. We selected variables with an increasing or decreasing trend with higher quartiles at P < 0.05, to which multivariate logistic regression analysis was applied. This revealed a positive association of age (odds ratio [OR]: 1.10 per year, 95% confidence interval [CI]: 1.07-1.12) and white blood cell count (OR: 1.01 per 1 × 103/µl, 95% CI: 1.00-1.01) with drusen. When the monkeys were divided by age, the association between drusen and white blood cell count was only evident in younger monkeys (OR: 1.01 per 1 × 103/µl, 95% CI: 1.00-1.02). In conclusion, age and white blood cell count may be associated with drusen development in M. fascicularis. Systemic inflammation may contribute to drusen formation in monkeys.

An Oral Aß Vaccine Using a Recombinant Adeno-Associated Virus Vector in Aged Monkeys: Reduction in Plaque Amyloid and Increase in Aß Oligomers.

With the objective to improve the amyloid-ß (Aß) targeting immunotherapy, we investigated the safety and efficacy of an oral vaccine with recombinant adeno-associated virus vector carrying a signal sequence and Aß1-43 cDNA (rAAV/Aß) in old non-human primates, 12 African green and 10 cynomolgus monkeys. The enteric-dissolving coated capsules containing rAAV/Aß were orally administered once or twice, then monkeys' conditions were carefully observed with complete blood count and laboratory examinations of the sera. General conditions, food intake, water intake, stool conditions, body weight changes, and menstruation cycles were not significantly altered, and laboratory tests and pathological examinations of the systemic organs were unremarkable. Pathological examinations of the brain showed significant reduction of the amyloid plaque burden and intracellular Aß without inflammatory or hemorrhagic changes in the brain. However, soluble Aß and some Aß oligomers were increased in rAAV-treated monkey brains without changes of the neuronal density and vascular amyloidosis. Thus, this vaccine seems to be safe in general, but we must be cautious about the increase of Aß oligomers after vaccination. This vaccine may be recommended at a very early stage of Alzheimer's disease when little amyloid is deposited.

Serological surveillance for antibodies against Erysipelothrix species in wild boar and deer in Japan.

We investigated the seroprevalence of antibodies against Erysipelothrix in wild animals in Japan. Serum samples were collected from 48 wild boar, 26 Yezo deer and 26 Japanese deer in Japan. Growth agglutination (GA) test was performed to estimate antibody titers. As a result, positive results were obtained from 32 (66.7%), 1 (3.6%) and 6 (23.1%) samples from wild boar, Yezo deer and Japanese deer, respectively. Our findings suggest that wild animals may be an important reservoir of Erysipelothrix.

DNA/RNA heteroduplex oligonucleotide for highly efficient gene silencing.

Antisense oligonucleotides (ASOs) are recognized therapeutic agents for the modulation of specific genes at the post-transcriptional level. Similar to any medical drugs, there are opportunities to improve their efficacy and safety. Here we develop a short DNA/RNA heteroduplex oligonucleotide (HDO) with a structure different from double-stranded RNA used for short interfering RNA and single-stranded DNA used for ASO. A DNA/locked nucleotide acid gapmer duplex with an α-tocopherol-conjugated complementary RNA (Toc-HDO) is significantly more potent at reducing the expression of the targeted mRNA in liver compared with the parent single-stranded gapmer ASO. Toc-HDO also improves the phenotype in disease models more effectively. In addition, the high potency of Toc-HDO results in a reduction of liver dysfunction observed in the parent ASO at a similar silencing effect. HDO technology offers a novel concept of therapeutic oligonucleotides, and the development of this molecular design opens a new therapeutic field.

Emergence of infectious malignant thrombocytopenia in Japanese macaques (Macaca fuscata) by SRV-4 after transmission to a novel host.

We discovered a lethal hemorrhagic syndrome arising from severe thrombocytopenia in Japanese macaques kept at the Primate Research Institute, Kyoto University. Extensive investigation identified that simian retrovirus type 4 (SRV-4) was the causative agent of the disease. SRV-4 had previously been isolated only from cynomolgus macaques in which it is usually asymptomatic. We consider that the SRV-4 crossed the so-called species barrier between cynomolgus and Japanese macaques, leading to extremely severe acute symptoms in the latter. Infectious agents that cross the species barrier occasionally amplify in virulence, which is not observed in the original hosts. In such cases, the new hosts are usually distantly related to the original hosts. However, Japanese macaques are closely related to cynomolgus macaques, and can even hybridize when given the opportunity. This lethal outbreak of a novel pathogen in Japanese macaques highlights the need to modify our expectations about virulence with regards crossing species barriers.

Ultrasensitive detection of PrP(Sc) in the cerebrospinal fluid and blood of macaques infected with bovine spongiform encephalopathy prion.

Prion diseases are characterized by the prominent accumulation of the misfolded form of a normal cellular protein (PrP(Sc)) in the central nervous system. The pathological features and biochemical properties of PrP(Sc) in macaque monkeys infected with the bovine spongiform encephalopathy (BSE) prion have been found to be similar to those of human subjects with variant Creutzfeldt-Jakob disease (vCJD). Non-human primate models are thus ideally suited for performing valid diagnostic tests and determining the efficacy of potential therapeutic agents. In the current study, we developed a highly efficient method for in vitro amplification of cynomolgus macaque BSE PrP(Sc). This method involves amplifying PrP(Sc) by protein misfolding cyclic amplification (PMCA) using mouse brain homogenate as a PrP(C) substrate in the presence of sulfated dextran compounds. This method is capable of amplifying very small amounts of PrP(Sc) contained in the cerebrospinal fluid (CSF) and white blood cells (WBCs), as well as in the peripheral tissues of macaques that have been intracerebrally inoculated with the BSE prion. After clinical signs of the disease appeared in three macaques, we detected PrP(Sc) in the CSF by serial PMCA, and the CSF levels of PrP(Sc) tended to increase with disease progression. In addition, PrP(Sc) was detectable in WBCs at the clinical phases of the disease in two of the three macaques. Thus, our highly sensitive, novel method may be useful for furthering the understanding of the tissue distribution of PrP(Sc) in non-human primate models of CJD.

Dynein dysfunction disrupts ß-amyloid clearance in astrocytes through endocytic disturbances.

We showed previously that aging attenuates the interaction between dynein-dynactin complexes in cynomolgus monkey brain and that dynein dysfunction reproduces age-dependent endocytic disturbances, resulting in intracellular ß-amyloid (Aß) accumulation, synaptic vesicle transport deficits, and neuritic swelling. It remains unclear whether such endocytic disturbances also occur in glial cells. Here, we show that endocytic pathology, such as intracellular accumulation of enlarged endosomes, occurs in astrocytes of aged monkey brains. Also, Aß accumulates in these enlarged endosomes. RNA interference studies have shown that dynein dysfunction reproduces astroglial endocytic pathology and disrupts Aß clearance in astrocytes through endocytic disturbances. These findings suggest that endocytic disturbances can alter astroglial functions and may also be involved in age-dependent Aß pathology.

Minimizing the inhibitory effect of neutralizing antibody for efficient gene expression in the liver with adeno-associated virus 8 vectors.

Neutralizing antibodies (NAbs) against adeno-associated viruses (AAVs) are known to interfere with AAV vector-mediated gene transfer by intravascular delivery. Evading the inhibitory effects of antibodies against AAV vectors is necessary for efficient transfer of therapeutic genes clinically. For this purpose, we tested the efficacy of saline flushing in order to avoid contact of vectors with NAbs present in blood. Direct injection of the AAV8 vector carrying the factor IX (FIX) gene into the portal vein of macaques using saline flushing achieved transgene-derived FIX expression (4.7 ± 2.10-10.1 ± 5.45% of normal human FIX concentration) in the presence of NAbs. Expression was as efficient as that (5.43 ± 2.59-12.68 ± 4.83%) in macaques lacking NAbs. We next tested the efficacy of saline flushing using less invasive balloon catheter-guided injection. This approach also resulted in efficient expression of transgene-derived FIX (2.5 ± 1.06-9.0 ± 2.37%) in the presence of NAbs (14-56× dilutions). NAbs at this range of titers reduced the efficiency of transduction in the macaque liver by 100-fold when the same vector was injected into mesenteric veins without balloon catheters. Our results suggest that portal vein-directed vector delivery strategies with flushing to remove blood are efficacious for minimizing the inhibitory effect of anti-AAV antibodies.