Production of a heterozygous exon skipping model of common marmosets using gene-editing technology.

Nonhuman primates (NHPs), which are closely related to humans, are useful in biomedical research, and an increasing number of NHP disease models have been reported using gene editing. However, many disease-related genes cause perinatal death when manipulated homozygously by gene editing. In addition, NHP resources, which are limited, should be efficiently used. Here, to address these issues, we developed a method of introducing heterozygous genetic modifications into common marmosets by combining Platinum transcription activator-like effector nuclease (TALEN) and a gene-editing strategy in oocytes. We succeeded in introducing the heterozygous exon 9 deletion mutation in the presenilin 1 gene, which causes familial Alzheimer's disease in humans, using this technology. As a result, we obtained animals with the expected genotypes and confirmed several Alzheimer's disease-related biochemical changes. This study suggests that highly efficient heterozygosity-oriented gene editing is possible using TALEN and oocytes and is an effective method for producing genetically modified animals.

Development of a 3D tracking system for multiple marmosets under free-moving conditions.

Assessment of social interactions and behavioral changes in nonhuman primates is useful for understanding brain function changes during life events and pathogenesis of neurological diseases. The common marmoset (Callithrix jacchus), which lives in a nuclear family like humans, is a useful model, but longitudinal automated behavioral observation of multiple animals has not been achieved. Here, we developed a Full Monitoring and Animal Identification (FulMAI) system for longitudinal detection of three-dimensional (3D) trajectories of each individual in multiple marmosets under free-moving conditions by combining video tracking, Light Detection and Ranging, and deep learning. Using this system, identification of each animal was more than 97% accurate. Location preferences and inter-individual distance could be calculated, and deep learning could detect grooming behavior. The FulMAI system allows us to analyze the natural behavior of individuals in a family over their lifetime and understand how behavior changes due to life events together with other data.

Prognostic Factors for Discharge Directly Home in Patients With Thoracoscopic Surgery for Empyema: A Multicenter Retrospective Cohort Study.

Background: Video-assisted thoracoscopic surgery is a widely recommended treatment for empyema in advanced stages. However, only a few studies have evaluated prognostic factors among patients with empyema who underwent video-assisted thoracoscopic surgery. Furthermore, no studies have evaluated predictors of direct discharge home. Patients and Methods: This multicenter retrospective cohort study included 161 patients with empyema who underwent video-assisted thoracoscopic surgery in five acute-care hospitals. The primary outcome was the probability of direct discharge home. The secondary outcome was the length of hospital stay after surgery. We broadly assessed pre-operative factors and performed univariable logistic regression for the direct discharge home and univariable gamma regression for the length of hospital stay after surgery. Results: Of the 161 included patients, 74.5% were directly discharged home. Age (>70 years; -24.3%); altered mental status (-33.4%); blood urea nitrogen (>22.4 mg/dL; -19.4%); and pleural pH (<7.2; -17.6%) were associated with high probabilities of not being directly discharged home. Fever (15.2%) and albumin (> 2.7 g/dL; 20.2%) were associated with high probabilities of being directly discharged home. The median length of stay after surgery was 19 days. Age (>70 years; 6.2 days); altered mental status (5.6 days); purulence (2.7 days); pleural thickness (>2 cm; 5.1 days); bronchial fistula (14.6 days); albumin (>2.7 g/dL; 3.1 days); and C-reactive protein (>20 mg/dL; 3.6 days) were associated with a longer post-operation hospital stay. Conclusions: Physicians should consider using these prognostic factors to predict non-direct discharge to the home for patients with empyema.

Primary Cytomegalovirus Pneumonia Successfully Treated with Corticosteroid Therapy and Valganciclovir.

Cytomegalovirus infection is typically asymptomatic in immunocompetent individuals. A 26-year-old woman was admitted to our hospital with a fever and breathlessness. Chest computed tomography (CT) revealed bilateral diffuse reticulation and nodules. Laboratory investigations showed atypical lymphocytosis and increased transaminases. She was treated with corticosteroid pulse therapy because of acute lung injury, and her clinical condition improved. Based on the presence of cytomegalovirus antibodies, antigen, and polymerase chain reaction findings, she was diagnosed with primary cytomegalovirus pneumonia and treated with valganciclovir. Primary cytomegalovirus pneumonia is very rare in immunocompetent individuals. The efficacy of corticosteroid and valganciclovir against cytomegalovirus pneumonia in this patient is noteworthy.

Thin-slice Two-dimensional T2-weighted Imaging with Deep Learning-based Reconstruction: Improved Lesion Detection in the Brain of Patients with Multiple Sclerosis.

PURPOSE: Brain MRI with high spatial resolution allows for a more detailed delineation of multiple sclerosis (MS) lesions. The recently developed deep learning-based reconstruction (DLR) technique enables image denoising with sharp edges and reduced artifacts, which improves the image quality of thin-slice 2D MRI. We, therefore, assessed the diagnostic value of 1 mm-slice-thickness 2D T2-weighted imaging (T2WI) with DLR (1 mm T2WI with DLR) compared with conventional MRI for identifying MS lesions. METHODS: Conventional MRI (5 mm T2WI, 2D and 3D fluid-attenuated inversion recovery) and 1 mm T2WI with DLR (imaging time: 7 minutes) were performed in 42 MS patients. For lesion detection, two neuroradiologists counted the MS lesions in two reading sessions (conventional MRI interpretation with 5 mm T2WI and MRI interpretations with 1 mm T2WI with DLR). The numbers of lesions per region category (cerebral hemisphere, basal ganglia, brain stem, cerebellar hemisphere) were then compared between the two reading sessions. RESULTS: For the detection of MS lesions by 2 neuroradiologists, the total number of detected MS lesions was significantly higher for MRI interpretation with 1 mm T2WI with DLR than for conventional MRI interpretation with 5 mm T2WI (765 lesions vs. 870 lesions at radiologist A, < 0.05). In particular, of the 33 lesions in the brain stem, radiologist A detected 21 (63.6%) additional lesions by 1 mm T2WI with DLR. CONCLUSION: Using the DLR technique, whole-brain 1 mm T2WI can be performed in about 7 minutes, which is feasible for routine clinical practice. MRI with 1 mm T2WI with DLR enabled increased MS lesion detection, particularly in the brain stem.

Effectiveness of Immediate Video-Assisted Thoracoscopic Surgery for Empyema: A Multicentre, Retrospective Cohort Study.

BACKGROUND: Because of limitations in previous randomised controlled trials and observational studies, the effectiveness of immediate video-assisted thoracoscopic surgery (VATS) for patients with empyema in real-world settings remains unclear. OBJECTIVE: This study aimed to evaluate whether immediate VATS improves clinical outcomes in patients with empyema. METHODS: This multicentre retrospective cohort study included 744 patients with physician-diagnosed empyema from six hospitals between 2006 and 2021. The exposure was VATS performed within 3 days of empyema diagnosis, the primary outcome was 30-day mortality, and secondary outcomes were 90-day mortality, length of hospital stay, and time from diagnosis to discharge. We used propensity score weighting to account for potential confounders. For outcome analyses, we used logistic regression for mortality outcomes and gamma regression for the number of days. RESULTS: Among the 744 patients, 53 (7.1%) underwent VATS within 3 days, and 691 (92.9%) initially received conservative treatment. After propensity score weighting, the differences in 30- and 90-day mortalities between the immediate VATS and initial conservative treatment groups were 1.18% (95% confidence interval [CI], -10.7 to 13.0%) and -0.08% (95% CI, -10.3 to 10.2%), respectively. The differences in length of hospital stay and time from diagnosis to discharge were -3.22 (95% CI, -6.19 to -0.25 days) and -5.04 days (95% CI, -8.19 to -1.90 days), respectively. CONCLUSIONS: Our real-world study showed that immediate VATS reduced the length of hospital stay and the time from diagnosis to discharge. Considering the small sample and differences in protocols between countries, further large-scale studies are warranted.

Prognostic Value of Computed Tomography in Empyema: A Multicenter Retrospective Cohort Study.

Rationale: Chest computed tomography is performed in patients with empyema for various reasons. However, its predictive ability for patient outcomes in empyema has not been evaluated. Objectives: To evaluate the predictive ability of computed tomography findings (pleural thickness, loculation, interlobar pleural effusion, lung abscess, and bronchopleural fistula) for 90-day mortality in empyema. Methods: This multicenter retrospective cohort study was conducted across six acute care hospitals in Japan. We included patients with confirmed empyema diagnoses who underwent chest computed tomography within 7 days of diagnosis. Imaging findings were defined as pleural thickness, loculation, interlobar pleural effusion, lung abscess, or bronchopleural fistula. One radiologist interpreted the computed tomography scans without patient information. The primary outcome was 90-day mortality. We calculated the differences in 90-day mortality between the presence and absence of each computed tomography finding using logistic regression with or without adjustment for early thoracic surgery. Results: A total of 711 patients were included in our study. Thoracic surgery was performed in 27% of patients, and the 90-day mortality rate was 10%. The differences (95% confidence intervals) in 90-day mortality without and with adjustment for early thoracic surgery were as follows: pleural thickness, 3.09% (-1.35% to 7.54%) and 2.70% (-1.80% to 7.20%); loculation, -4.01% (-8.61% to 0.60%) and -3.80% (-8.41% to 0.81%); interlobar pleural effusion, -9.15% (-14.58% to -3.72%) and -8.96% (-14.39% to -3.53%); lung abscess, 7.04% (-1.16% to 15.2%) and 6.86% (-1.34% to 15.05%); and bronchopleural fistula, 13.80% (7.66% to 19.94%) and 13.63% (7.50% to 19.77%), respectively. Conclusions: Although interlobar pleural effusion predicted lower 90-day mortality regardless of early thoracic surgery, the presence of bronchopleural fistula predicted higher 90-day mortality with empyema. Our results warrant further validation.

The common marmoset in biomedical research: experimental disease models and veterinary management.

The common marmoset, Callithrix jacchus, is increasingly being used as the preferred nonhuman primate (NHP) model in biomedical research. Marmosets share several physiological and biological similarities with humans, as a Simiiformes species, and their use in research programs advances knowledge in several fields. Their unique characteristics, such as their small size, high fecundity, and rapid growth, offer additional advances in laboratory settings. This article reviews the developments in experimental disease models using marmosets based on our experience at the Central Institute for Experimental Animals (CIEA) in Japan. The development of genetically modified marmoset models using advanced genome editing technology is attracting researchers, particularly in neuroscience-related fields. In parallel, various marmoset models of human diseases induced by surgery or drug administration have contributed to preclinical and translational studies. Among these are models for Parkinson's disease induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, spinal cord injury models, a model for type 1 diabetes induced by the combination of partial pancreatectomy and streptozotocin administration, and a hepatic fibrosis model induced by thioacetamide. The development of these models has been supported by refinements in veterinary care, such as the careful design of anesthetic protocols and better understanding of pathogenic microorganisms. In the second part of this review, we present a compilation of practices currently in use at CIEA that provide optimal animal care and enable safe experimentation.

Recent Advances in the Modeling of Alzheimer's Disease.

Since 1995, more than 100 transgenic (Tg) mouse models of Alzheimer's disease (AD) have been generated in which mutant amyloid precursor protein (APP) or APP/presenilin 1 (PS1) cDNA is overexpressed ( 1st generation models ). Although many of these models successfully recapitulate major pathological hallmarks of the disease such as amyloid ß peptide (Aß) deposition and neuroinflammation, they have suffered from artificial phenotypes in the form of overproduced or mislocalized APP/PS1 and their functional fragments, as well as calpastatin deficiency-induced early lethality, calpain activation, neuronal cell death without tau pathology, endoplasmic reticulum stresses, and inflammasome involvement. Such artifacts bring two important uncertainties into play, these being (1) why the artifacts arise, and (2) how they affect the interpretation of experimental results. In addition, destruction of endogenous gene loci in some Tg lines by transgenes has been reported. To overcome these concerns, single App knock-in mouse models harboring the Swedish and Beyreuther/Iberian mutations with or without the Arctic mutation (AppNL-G-F and AppNL-F mice) were developed ( 2nd generation models ). While these models are interesting given that they exhibit Aß pathology, neuroinflammation, and cognitive impairment in an age-dependent manner, the model with the Artic mutation, which exhibits an extensive pathology as early as 6 months of age, is not suitable for investigating Aß metabolism and clearance because the Aß in this model is resistant to proteolytic degradation and is therefore prone to aggregation. Moreover, it cannot be used for preclinical immunotherapy studies owing to the discrete affinity it shows for anti-Aß antibodies. The weakness of the latter model (without the Arctic mutation) is that the pathology may require up to 18 months before it becomes sufficiently apparent for experimental investigation. Nevertheless, this model was successfully applied to modulating Aß pathology by genome editing, to revealing the differential roles of neprilysin and insulin-degrading enzyme in Aß metabolism, and to identifying somatostatin receptor subtypes involved in Aß degradation by neprilysin. In addition to discussing these issues, we also provide here a technical guide for the application of App knock-in mice to AD research. Subsequently, a new double knock-in line carrying the AppNL-F and Psen1 P117L/WT mutations was generated, the pathogenic effect of which was found to be synergistic. A characteristic of this 3rd generation model is that it exhibits more cored plaque pathology and neuroinflammation than the AppNL-G-F line, and thus is more suitable for preclinical studies of disease-modifying medications targeting Aß. Furthermore, a derivative AppG-F line devoid of Swedish mutations which can be utilized for preclinical studies of ß-secretase modifier(s) was recently created. In addition, we introduce a new model of cerebral amyloid angiopathy that may be useful for analyzing amyloid-related imaging abnormalities that can be caused by anti-Aß immunotherapy. Use of the App knock-in mice also led to identification of the α-endosulfine-K ATP channel pathway as components of the somatostatin-evoked physiological mechanisms that reduce Aß deposition via the activation of neprilysin. Such advances have provided new insights for the prevention and treatment of preclinical AD. Because tau pathology plays an essential role in AD pathogenesis, knock-in mice with human tau wherein the entire murine Mapt gene has been humanized were generated. Using these mice, the carboxy-terminal PDZ ligand of neuronal nitric oxide synthase (CAPON) was discovered as a mediator linking tau pathology to neurodegeneration and showed that tau humanization promoted pathological tau propagation. Finally, we describe and discuss the current status of mutant human tau knock-in mice and a non-human primate model of AD that we have successfully created.

Two cases of trastuzumab deruxtecan-induced interstitial lung disease in advanced breast cancer.

Trastuzumab deruxtecan (T-DXd) frequently induces interstitial lung disease (ILD) more than other anti-human epidermal growth factor receptor 2 therapies. We diagnosed two cases of ILD induced by T-DXd in patients with advanced breast cancer. The first case is that of a 57-year-old Japanese woman who complained of dyspnoea and fever after 4 cycles of T-DXd. Chest computed tomography (CT) showed diffuse consolidation and a reticular shadow. The second case was that of a 72-year-old Japanese woman who complained of dyspnoea after 3 cycles of T-DXd. Chest CT showed a reticular shadow predominantly in the left lung. Both patients were treated with corticosteroids, including pulse methylprednisolone; however, their general condition weakened due to ILD, long-term corticosteroid therapy and breast cancer progression. Subsequently, the patients were unable to continue chemotherapy for breast cancer. To the best of our knowledge, this is the first report in a real-world clinical setting.

Predicting in-hospital death in pneumonic COPD exacerbation via BAP-65, CURB-65 and machine learning.

INTRODUCTION: There is no established clinical prediction model for in-hospital death among patients with pneumonic COPD exacerbation. We aimed to externally validate BAP-65 and CURB-65 and to develop a new model based on the eXtreme Gradient Boosting (XGBoost) algorithm. METHODS: This multicentre cohort study included patients aged ≥40 years with pneumonic COPD exacerbation. The input data were age, sex, activities of daily living, mental status, systolic and diastolic blood pressure, respiratory rate, heart rate, peripheral blood eosinophil count and blood urea nitrogen. The primary outcome was in-hospital death. BAP-65 and CURB-65 underwent external validation using the area under the receiver operating characteristic curve (AUROC) in the whole dataset. We used XGBoost to develop a new prediction model. We compared the AUROCs of XGBoost with that of BAP-65 and CURB-65 in the test dataset using bootstrap sampling. RESULTS: We included 1190 patients with pneumonic COPD exacerbation. The in-hospital mortality was 7% (88 out of 1190). In the external validation of BAP-65 and CURB-65, the AUROCs (95% confidence interval) of BAP-65 and CURB-65 were 0.69 (0.66-0.72) and 0.69 (0.66-0.72), respectively. XGBoost showed an AUROC of 0.71 (0.62-0.81) in the test dataset. There was no significant difference in the AUROCs of XGBoost versus BAP-65 (absolute difference 0.054; 95% CI -0.057-0.16) or versus CURB-65 (absolute difference 0.0021; 95% CI -0.091-0.088). CONCLUSION: BAP-65, CURB-65 and XGBoost showed low predictive performance for in-hospital death in pneumonic COPD exacerbation. Further large-scale studies including more variables are warranted.

The prognostic factors of in-hospital death among patients with pneumonic COPD acute exacerbation.

BACKGROUND: Pneumonic acute exacerbation of chronic obstructive pulmonary disease (COPD-AE) is associated with worse outcomes compared with non-pneumonic COPD-AE. We aimed to explore prognostic factors among patients with pneumonic COPD-AE. METHODS: This multicentered retrospective cohort study was conducted across five hospitals in Japan. Hospitalized patients ≥40 years of age with pneumonic COPD-AE who were administered systemic corticosteroids during hospitalization were included. Patients with other causes of respiratory failure, daily systemic steroid users, and patients who were not treated with systemic steroids were excluded. Based on existing clinical prediction models, the following potential prognostic factors were selected in advance: age, blood eosinophil count, blood urea nitrogen, respiratory rate, diastolic blood pressure, and altered mental status. Multivariate logistic regression was conducted to determine the association between potential prognostic factors and in-hospital death. RESULTS: After excluding 897 patients based on the exclusion criteria, 669 patients with pneumonic COPD-AE who were administered systemic corticosteroids were included. The in-hospital mortality rate was 5.1%. Altered mental status was associated with mortality (odds ratio, 4.47; 95% confidence intervals, 2.00 to 10.00), and eosinophilia was associated with a lower risk of mortality (odds ratio, 0.19; 95% confidence intervals: 0.06 to 0.56). CONCLUSIONS: Altered mental status may be a prognostic factor for in-hospital death among patients with pneumonic COPD-AE who were administered systemic corticosteroids. Moreover, eosinophilia may be a prognostic factor for lower in-hospital mortality rate among these patients.

Effectiveness of empirical anti-pseudomonal antibiotics for recurrent COPD exacerbation: a multicenter retrospective cohort study.

Although frequent chronic obstructive pulmonary disease (COPD) exacerbation has been associated with the isolation of Pseudomonas aeruginosa (PA) in sputum cultures, it remains unknown whether the empirical use of anti-pseudomonal antibiotics can improve outcomes in patients with frequent COPD exacerbations. This multicenter retrospective cohort study evaluated whether the empirical use of anti-pseudomonal antibiotics improves the length of the hospital stay in patients with recurrent COPD exacerbation (≥ 2 admissions from April 1, 2008 to July 31, 2020). For statistical analysis, a log-linked Gamma model was used. Parameters were estimated using a generalized estimating equation model with an exchangeable correlation structure accounting for repeated observations from a single patient. Covariates included age, body mass index, home oxygen therapy use, respiratory rate, heart rate, oxygen use on admission, mental status, systemic steroid use, activities of daily living, and the number of recurrences. Hospital-specific effects were specified as fixed effects. In total, 344 patients and 965 observations of recurrent COPD exacerbations were selected. Anti-pseudomonal antibiotics were used in 173 patients (18%). The estimated change in the length of the hospital stay between anti-pseudomonal and non-anti-pseudomonal antibiotics groups was 0.039 days [95% confidence interval; - 0.083, 0.162]. Anti-pseudomonal antibiotics could not shorten the length of the hospital stay.

Idiopathic Pulmonary Hemosiderosis Associated with Emphysematous Change in an Adult Who Underwent Lung Transplantation.

Idiopathic pulmonary hemosiderosis is characterized by repeated alveolar hemorrhaging. We herein report a 52-year-old Japanese woman who had shortness of breath, diffuse small nodules, thin-walled cysts, and bronchiolectasis. A surgical lung biopsy revealed peribronchial hemosiderosis, centrilobular emphysema, and fragile elastic fibers of the alveolar septa and small vessels. She ultimately underwent living-donor lung transplantation five years after the first visit.

Effectiveness of Steroid Therapy on Pneumonic Chronic Obstructive Pulmonary Disease Exacerbation: A Multicenter, Retrospective Cohort Study.

Purpose: To date, no consensus exists on the effects of systemic steroid use on pneumonic chronic obstructive pulmonary disease (COPD) exacerbation owing to trial design issues in previous trials involving these conditions. This multicenter study aimed to evaluate more precisely the effectiveness of the use of systemic steroids in treating pneumonic COPD exacerbation in a larger sample by adjusting for confounding factors. Patients and Methods: This multicenter, retrospective, observational study was conducted across five acute general hospitals in Japan. We analyzed the association between parenteral/oral steroid therapy and time to clinical stability in pneumonic COPD exacerbation. We used a validated algorithm derived from the 10th revision of the International Classification of Diseases and Related Health Problems (ICD-10) to include patients with pneumonic COPD exacerbation. We excluded patients with other hypoxia causes (asthma exacerbation, pneumothorax, heart failure) and complicated pneumonia (obstructive pneumonia, empyema), those who required tracheal intubation/vasopressors, and those who were clinically stable on day of admission. The primary outcome was the time to clinical stability. Multiple imputation was used for missing data. Propensity scores within each imputed dataset were calculated using potential confounding factors. The Fine and Gray model was used within each dataset to account for the competing risk of death and hospital discharge without clinical stability, and we combined the results. Results: Altogether, 1237 patients were included. Systemic steroid therapy was administered to 658 patients (53%). The pooled estimated subdistribution hazard ratio of time to clinical stability in steroid vs non-steroid users was 0.89 (95% confidence interval, 0.78 to 1.0). Conclusion: This study revealed that systemic steroid therapy may not improve the time to clinical stability in patients with pneumonic COPD exacerbation of mild to moderate severity. Further randomized controlled trials including more severe patients will be needed to evaluate the effectiveness of systemic steroid therapy accurately.

Efficient generation of Knock-in/Knock-out marmoset embryo via CRISPR/Cas9 gene editing.

Genetically modified nonhuman primates (NHP) are useful models for biomedical research. Gene editing technologies have enabled production of target-gene knock-out (KO) NHP models. Target-gene-KO/knock-in (KI) efficiency of CRISPR/Cas9 has not been extensively investigated in marmosets. In this study, optimum conditions for target gene modification efficacies of CRISPR/mRNA and CRISPR/nuclease in marmoset embryos were examined. CRISPR/nuclease was more effective than CRISPR/mRNA in avoiding mosaic genetic alteration. Furthermore, optimal conditions to generate KI marmoset embryos were investigated using CRISPR/Cas9 and 2 different lengths (36 nt and 100 nt) each of a sense or anti-sense single-strand oligonucleotide (ssODN). KIs were observed when CRISPR/nuclease and 36 nt sense or anti-sense ssODNs were injected into embryos. All embryos exhibited mosaic mutations with KI and KO, or imprecise KI, of c-kit. Although further improvement of KI strategies is required, these results indicated that CRISPR/Cas9 may be utilized to produce KO/KI marmosets via gene editing.

Genetic engineering in nonhuman primates for human disease modeling.

Nonhuman primate (NHP) experimental models have contributed greatly to human health research by assessing the safety and efficacy of newly developed drugs, due to their physiological and anatomical similarities to humans. To generate NHP disease models, drug-inducible methods, and surgical treatment methods have been employed. Recent developments in genetic and developmental engineering in NHPs offer new options for producing genetically modified disease models. Moreover, in recent years, genome-editing technology has emerged to further promote this trend and the generation of disease model NHPs has entered a new era. In this review, we summarize the generation of conventional disease model NHPs and discuss new solutions to the problem of mosaicism in genome-editing technology.

Generation of a Nonhuman Primate Model of Severe Combined Immunodeficiency Using Highly Efficient Genome Editing.

Recent advances in genome editing have facilitated the generation of nonhuman primate (NHP) models, with potential to unmask the complex biology of human disease not revealed by rodent models. However, their broader use is hindered by the challenges associated with generation of adult NHP models as well as the cost of their production. Here, we describe the generation of a marmoset model of severe combined immunodeficiency (SCID). This study optimized zinc-finger nucleases (ZFNs) and transcription activator-like effector nucleases (TALENs) to target interleukin-2 receptor subunit gamma (IL2RG) in pronuclear stage marmoset embryos. Nine of 21 neonates exhibited mutations in the IL2RG gene, concomitant with immunodeficiency, and three neonates have currently survived from 240 days to 1.8 years. Our approach demonstrates highly efficient production of founder NHP with SCID phenotypes, with promises of multiple pre-clinical and translational applications.

Birth of healthy offspring following ICSI in in vitro-matured common marmoset (Callithrix jacchus) oocytes.

Intracytoplasmic sperm injection (ICSI), an important method used to treat male subfertility, is applied in the transgenic technology of sperm-mediated gene transfer. However, no study has described successful generation of offspring using ICSI in the common marmoset, a small non-human primate used as a model for biomedical translational research. In this study, we investigated blastocyst development and the subsequent live offspring stages of marmoset oocytes matured in vitro and fertilized by ICSI. To investigate the optimal timing of performing ICSI, corrected immature oocytes were matured in vitro and ICSI was performed at various time points (1-2 h, 2-4 h, 4-6 h, 6-8 h, and 8-10 h after extrusion of the first polar body (PB)). Matured oocytes were then divided randomly into two groups: one was used for in vitro fertilization (IVF) and the other for ICSI. To investigate in vivo development of embryos followed by ICSI, 6-cell- to 8-cell-stage embryos and blastocysts were nonsurgically transferred into recipient marmosets. Although no significant differences were observed in the fertilization rate of blastocysts among ICSI timing after the first PB extrusion, the blastocyst rate at 1-2 h was lowest among groups at 2-4 h, 4-6 h, 6-8 h, and 8-10 h. Comparing ICSI to IVF, the fertilization rates obtained in ICSI were higher than in IVF (p>0.05). No significant difference was noted in the cleaved blastocyst rate between ICSI and IVF. Following the transfer of 37 ICSI blastocysts, 4 of 20 recipients became pregnant, while with the transfer of 21 6-cell- to 8-cell-stage ICSI embryos, 3 of 8 recipients became pregnant. Four healthy offspring were produced and grew normally. These are the first marmoset offspring produced by ICSI, making it an effective fertilization method for marmosets.

Common marmoset as a new model animal for neuroscience research and genome editing technology.

The common marmoset (Callithrix jacchus) is a small New World primate; it originally comes from the Atlantic coastal forests in northeastern Brazil. It has been attracting much attention in the biomedical research field because of its size, availability, and unique biological characteristics. Its endocrinological and behavioral similarity to humans, comparative ease in handling, and high reproductive efficiency are very advantageous for neuroscience research. Recently, we developed transgenic common marmosets with germline transmission, and this technological breakthrough provides a potential paradigm shift by enabling researchers to investigate complex biological phenomena using genetically-modified non-human primates. In this review, we summarize recent progress in marmoset research, and also discuss a potential application of genome editing tools that should be useful toward the generation of knock-out/knock-in marmoset models.