Virological characteristics of the SARS-CoV-2 Omicron BA.2 spike.

Soon after the emergence and global spread of the SARS-CoV-2 Omicron lineage BA.1, another Omicron lineage, BA.2, began outcompeting BA.1. The results of statistical analysis showed that the effective reproduction number of BA.2 is 1.4-fold higher than that of BA.1. Neutralization experiments revealed that immunity induced by COVID vaccines widely administered to human populations is not effective against BA.2, similar to BA.1, and that the antigenicity of BA.2 is notably different from that of BA.1. Cell culture experiments showed that the BA.2 spike confers higher replication efficacy in human nasal epithelial cells and is more efficient in mediating syncytia formation than the BA.1 spike. Furthermore, infection experiments using hamsters indicated that the BA.2 spike-bearing virus is more pathogenic than the BA.1 spike-bearing virus. Altogether, the results of our multiscale investigations suggest that the risk of BA.2 to global health is potentially higher than that of BA.1.

Virological characteristics of the SARS-CoV-2 Omicron BA.2 subvariants, including BA.4 and BA.5.

After the global spread of the SARS-CoV-2 Omicron BA.2, some BA.2 subvariants, including BA.2.9.1, BA.2.11, BA.2.12.1, BA.4, and BA.5, emerged in multiple countries. Our statistical analysis showed that the effective reproduction numbers of these BA.2 subvariants are greater than that of the original BA.2. Neutralization experiments revealed that the immunity induced by BA.1/2 infections is less effective against BA.4/5. Cell culture experiments showed that BA.2.12.1 and BA.4/5 replicate more efficiently in human alveolar epithelial cells than BA.2, and particularly, BA.4/5 is more fusogenic than BA.2. We further provided the structure of the BA.4/5 spike receptor-binding domain that binds to human ACE2 and considered how the substitutions in the BA.4/5 spike play roles in ACE2 binding and immune evasion. Moreover, experiments using hamsters suggested that BA.4/5 is more pathogenic than BA.2. Our multiscale investigations suggest that the risk of BA.2 subvariants, particularly BA.4/5, to global health is greater than that of original BA.2.

Targeted demethylation and activation of NLRC5 augment cancer immunogenicity through MHC class I.

Impaired expression of MHC (major histocompatibility complex) class I in cancers constitutes a major mechanism of immune evasion. It has been well documented that the low level of MHC class I is associated with poor prognosis and resistance to checkpoint blockade therapies. However, there is lmited approaches to specifically induce MHC class I to date. Here, we show an approach for robust and specific induction of MHC class I by targeting an MHC class I transactivator (CITA)/NLRC5, using a CRISPR/Cas9-based gene-specific system, designated TRED-I (Targeted reactivation and demethylation for MHC-I). The TRED-I system specifically recruits a demethylating enzyme and transcriptional activators on the NLRC5 promoter, driving increased MHC class I antigen presentation and accelerated CD8+ T cell activation. Introduction of the TRED-I system in an animal cancer model exhibited tumor-suppressive effects accompanied with increased infiltration and activation of CD8+ T cells. Moreover, this approach boosted the efficacy of checkpoint blockade therapy using anti-PD1 (programmed cell death protein) antibody. Therefore, targeting NLRC5 by this strategy provides an attractive therapeutic approach for cancer.

A Case of Uterine Tumor Resembling Ovarian Sex Cord Tumor With Prominent Myxoid Features.

Uterine tumor resembling ovarian sex cord tumor (UTROSCT) is a rare tumor with low malignant potential that commonly occurs in middle age. Although more than 100 cases have been reported to date, myxoid morphology is not well documented. Here, we present a 75-yr-old woman with abnormal vaginal bleeding, with an 8-cm mass in the uterine corpus detected by irregular, high-intensity signaling on T2-weighted imaging. The uterine mass had a glistening mucinous appearance on gross examination. Microscopically, most of the tumor cells were floating in the myxoid stroma. The tumor cells formed clusters or nests with abundant cytoplasm, while some exhibited trabecular or rhabdoid appearances. Immunohistochemically, tumor cells were positive for pancytokeratin (AE1/AE3), α-smooth muscle actin, CD10, progesterone receptor, and some sex cord markers such as calretinin, inhibin, CD56, steroidogenic factor-1. Electron microscopy demonstrated epithelial and sex cord differentiation. This tumor was negative for JAZF1-JJAZ1 fusion gene that is frequently found in low-grade endometrial stromal sarcoma. Fusion genes related to UTROSCT, including NCOA2/3 , were not detected by reverse transcription polymerase chain reaction. The present case suggests that UTROSCT should be included in the differential diagnosis of myxoid uterine tumors.

Virological characteristics of the SARS-CoV-2 Omicron EG.5.1 variant.

In middle to late 2023, a sublineage of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron XBB, EG.5.1 (a progeny of XBB.1.9.2), is spreading rapidly around the world. We performed multiscale investigations, including phylogenetic analysis, epidemic dynamics modeling, infection experiments using pseudoviruses, clinical isolates, and recombinant viruses in cell cultures and experimental animals, and the use of human sera and antiviral compounds, to reveal the virological features of the newly emerging EG.5.1 variant. Our phylogenetic analysis and epidemic dynamics modeling suggested that two hallmark substitutions of EG.5.1, S:F456L and ORF9b:I5T are critical to its increased viral fitness. Experimental investigations on the growth kinetics, sensitivity to clinically available antivirals, fusogenicity, and pathogenicity of EG.5.1 suggested that the virological features of EG.5.1 are comparable to those of XBB.1.5. However, cryo-electron microscopy revealed structural differences between the spike proteins of EG.5.1 and XBB.1.5. We further assessed the impact of ORF9b:I5T on viral features, but it was almost negligible in our experimental setup. Our multiscale investigations provide knowledge for understanding the evolutionary traits of newly emerging pathogenic viruses, including EG.5.1, in the human population.

Atelocollagen-associated autologous chondrocyte implantation for the repair of large cartilage defects of the knee: Results at three to seven years.

BACKGROUND: Recently, various types of engineered autologous chondrocyte implantation (ACI) have been developed. Atelocollagen-associated ACI (A-ACI) is the only ACI procedure covered by Japanese Health Insurance since 2013. The indications of the A-ACI are traumatic cartilage defects and osteochondral dissecans (OCD) for knee joints. PURPOSE: To evaluate midterm clinical results after A-ACI for the treatment for full-thickness cartilage defects of the knee. METHODS: Thirteen consecutive patients who underwent A-ACI between 2014 and 2018 had been prospectively enrolled in this study. There were 11 men and 2 women with a mean age of 34 years at the time of surgery. The causes of the cartilage defect were trauma in 10 knees and OCD in 3 knees. The total number of lesions was 15, which were comprised of the medial femoral condyle in 5 knees, the lateral femoral condyle in 5 knees, and the femoral trochlea in 5 knees. The mean size of the lesion was 5.3 cm2. Each knee was clinically and radiologically evaluated preoperatively and postoperatively. RESULTS: The mean Lysholm score improved significantly from 74.0 points to 94.0 points (p = 0.008) and each subscale in Knee injury and Osteoarthritis Outcome Score improved significantly (p < 0.001) at the mean final follow-up period of 51 months (range, 36-84 months). The magnetic resonance observation of cartilage repair tissue 2.0 score at the mean follow-up of 38 months was significantly higher than that at 2 months postoperatively (p = 0.014). According to the International Cartilage Repair Society (ICRS) grading scale, 3 knees were graded as normal, 3 knees as nearly normal, and 1 knee as severely abnormal in second-look arthroscopic evaluation at a mean of 22 months (range, 8-41 months) after A-ACI. CONCLUSION: The present study showed a significant subjective and objective clinical improvement in the A-ACI for large cartilage defects of the knee at a mean follow-up of 51 months (range, 36-84 months).

An autopsy case report of adult-onset Krabbe disease: Comparison with an infantile-onset case.

Krabbe disease is a lysosomal storage disease caused by a deficiency of the galactocerebrosidase (GALC) enzyme, which leads to demyelination of the central and peripheral nervous systems. Almost all patients with Krabbe disease are infants, and this is the first report of adult-onset cases that describe pathological findings. Here, we present two autopsy cases: a 73-year-old female and a 2-year-old male. The adult-onset case developed symptoms in her late thirties and was diagnosed by the identification of GALC D528N and L634S mutations and by T2-weighted magnetic resonance imaging; she had increased signal in the white matter along the pyramidal tract to the bilateral precentral gyrus, as well as from the triangular part to the posterior horn of the lateral ventricle. Microscopically, Klüver-Barrera staining was pale in the white matter of the precentral gyrus and occipito-thalamic radiation, and a few globoid cells were observed. The GALC mutations that were identified in the present adult-onset case do not completely inactivate GALC enzyme activity, resulting in focal demyelination of the brain.

Slow and deep respiration suppresses steady-state sympathetic nerve activity in patients with chronic heart failure: from modeling to clinical application.

Influences of slow and deep respiration on steady-state sympathetic nerve activity remain controversial in humans and could vary depending on disease conditions and basal sympathetic nerve activity. To elucidate the respiratory modulation of steady-state sympathetic nerve activity, we modeled the dynamic nature of the relationship between lung inflation and muscle sympathetic nerve activity (MSNA) in 11 heart failure patients with exaggerated sympathetic outflow at rest. An autoregressive exogenous input model was utilized to simulate entire responses of MSNA to variable respiratory patterns. In another 18 patients, we determined the influence of increasing tidal volume and slowing respiratory frequency on MSNA; 10 patients underwent a 15-min device-guided slow respiration and the remaining 8 had no respiratory modification. The model predicted that a 1-liter, step increase of lung volume decreased MSNA dynamically; its nadir (-33 ± 22%) occurred at 2.4 s; and steady-state decrease (-15 ± 5%), at 6 s. Actually, in patients with the device-guided slow and deep respiration, respiratory frequency effectively fell from 16.4 ± 3.9 to 6.7 ± 2.8/min (P < 0.0001) with a concomitant increase in tidal volume from 499 ± 206 to 1,177 ± 497 ml (P < 0.001). Consequently, steady-state MSNA was decreased by 31% (P < 0.005). In patients without respiratory modulation, there were no significant changes in respiratory frequency, tidal volume, and steady-state MSNA. Thus slow and deep respiration suppresses steady-state sympathetic nerve activity in patients with high levels of resting sympathetic tone as in heart failure.

Differing effects of adaptive servoventilation and continuous positive airway pressure on muscle sympathetic nerve activity in patients with heart failure.

BACKGROUND: Long-term adaptive servoventilation (ASV) increases cardiac function more effectively than continuous positive airway pressure (CPAP), possibly via alleviation of sympathetic overactivation. The present study evaluated the effect of ASV and CPAP at comparable pressure on muscle sympathetic nerve activity (MSNA) in patients with heart failure (HF) and with or without periodic breathing (PB). METHODS AND RESULTS: A total of 57 patients with HF (ejection fraction <0.45) were randomized to receive CPAP (n=28) or ASV (n=29). Respiratory profiles and MSNA were continuously monitored before and during CPAP and ASV (30min) at pressures of 6.5 and 6.6cmH2O, respectively. The severity of respiratory instability was determined using the coefficient of variation of tidal volume (CV-TV). Although heart rate and blood pressure remained unchanged, only ASV improved CV-TV. MSNA decreased in the ASV (P<0.001), but not in the CPAP group. The change in CV-TV independently predicted changes in MSNA (P<0.001). Device type and PB significantly interacted with changes in MSNA (P<0.05) and ASV exerted sympathoinhibitory effects in patients with PB, whereas CPAP did not. A sympathoinhibitory effect in patients without PB was not evident in either treatment arm. CONCLUSIONS: ASV probably exerts its sympathoinhibitory effects in patients with HF and PB through pressure support.

Akaluc bioluminescence offers superior sensitivity to track in vivo dynamics of SARS-CoV-2 infection.

Monitoring in vivo viral dynamics can improve our understanding of pathogenicity and tissue tropism. Because the gene size of RNA viruses is typically small, NanoLuc is the primary choice for accommodation within viral genome. However, NanoLuc/Furimazine and also the conventional firefly luciferase/D-luciferin are known to exhibit relatively low tissue permeability and thus less sensitivity for visualization of deep tissue including lungs. Here, we demonstrated in vivo sufficient visualization of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection using the pair of a codon-optimized Akaluc and AkaLumine. We engineered the codon-optimized Akaluc gene possessing the similar GC ratio of SARS-CoV-2. Using the SARS-CoV-2 recombinants carrying the codon-optimized Akaluc, we visualized in vivo infection of respiratory organs, including the tissue-specific differences associated with particular variants. Additionally, we could evaluate the efficacy of antivirals by monitoring changes in Akaluc signals. Overall, we offer an effective technology for monitoring viral dynamics in live animals.

Virological characteristics of the SARS-CoV-2 BA.2.86 variant.

In late 2023, several SARS-CoV-2 XBB descendants, notably EG.5.1, were predominant worldwide. However, a distinct SARS-CoV-2 lineage, the BA.2.86 variant, also emerged. BA.2.86 is phylogenetically distinct from other Omicron sublineages, accumulating over 30 amino acid mutations in its spike protein. Here, we examined the virological characteristics of the BA.2.86 variant. Our epidemic dynamics modeling suggested that the relative reproduction number of BA.2.86 is significantly higher than that of EG.5.1. Additionally, four clinically available antivirals were effective against BA.2.86. Although the fusogenicity of BA.2.86 spike is similar to that of the parental BA.2 spike, the intrinsic pathogenicity of BA.2.86 in hamsters was significantly lower than that of BA.2. Since the growth kinetics of BA.2.86 are significantly lower than those of BA.2 both in vitro and in vivo, the attenuated pathogenicity of BA.2.86 is likely due to its decreased replication capacity. These findings uncover the features of BA.2.86, providing insights for control and treatment.

Virological characteristics of the SARS-CoV-2 Omicron XBB.1.5 variant.

Circulation of SARS-CoV-2 Omicron XBB has resulted in the emergence of XBB.1.5, a new Variant of Interest. Our phylogenetic analysis suggests that XBB.1.5 evolved from XBB.1 by acquiring the S486P spike (S) mutation, subsequent to the acquisition of a nonsense mutation in ORF8. Neutralization assays showed similar abilities of immune escape between XBB.1.5 and XBB.1. We determine the structural basis for the interaction between human ACE2 and the S protein of XBB.1.5, showing similar overall structures between the S proteins of XBB.1 and XBB.1.5. We provide the intrinsic pathogenicity of XBB.1 and XBB.1.5 in hamsters. Importantly, we find that the ORF8 nonsense mutation of XBB.1.5 resulted in impairment of MHC suppression. In vivo experiments using recombinant viruses reveal that the XBB.1.5 mutations are involved with reduced virulence of XBB.1.5. Together, our study identifies the two viral functions defined the difference between XBB.1 and XBB.1.5.

Virological characteristics of a SARS-CoV-2-related bat coronavirus, BANAL-20-236.

BACKGROUND: Although several SARS-CoV-2-related coronaviruses (SC2r-CoVs) were discovered in bats and pangolins, the differences in virological characteristics between SARS-CoV-2 and SC2r-CoVs remain poorly understood. Recently, BANAL-20-236 (B236) was isolated from a rectal swab of Malayan horseshoe bat and was found to lack a furin cleavage site (FCS) in the spike (S) protein. The comparison of its virological characteristics with FCS-deleted SARS-CoV-2 (SC2ΔFCS) has not been conducted yet. METHODS: We prepared human induced pluripotent stem cell (iPSC)-derived airway and lung epithelial cells and colon organoids as human organ-relevant models. B236, SARS-CoV-2, and artificially generated SC2ΔFCS were used for viral experiments. To investigate the pathogenicity of B236 in vivo, we conducted intranasal infection experiments in hamsters. FINDINGS: In human iPSC-derived airway epithelial cells, the growth of B236 was significantly lower than that of the SC2ΔFCS. A fusion assay showed that the B236 and SC2ΔFCS S proteins were less fusogenic than the SARS-CoV-2 S protein. The infection experiment in hamsters showed that B236 was less pathogenic than SARS-CoV-2 and even SC2ΔFCS. Interestingly, in human colon organoids, the growth of B236 was significantly greater than that of SARS-CoV-2. INTERPRETATION: Compared to SARS-CoV-2, we demonstrated that B236 exhibited a tropism toward intestinal cells rather than respiratory cells. Our results are consistent with a previous report showing that B236 is enterotropic in macaques. Altogether, our report strengthens the assumption that SC2r-CoVs in horseshoe bats replicate primarily in the intestinal tissues rather than respiratory tissues. FUNDING: This study was supported in part by AMED ASPIRE (JP23jf0126002, to Keita Matsuno, Kazuo Takayama, and Kei Sato); AMED SCARDA Japan Initiative for World-leading Vaccine Research and Development Centers "UTOPIA" (JP223fa627001, to Kei Sato), AMED SCARDA Program on R&D of new generation vaccine including new modality application (JP223fa727002, to Kei Sato); AMED SCARDA Hokkaido University Institute for Vaccine Research and Development (HU-IVReD) (JP223fa627005h0001, to Takasuke Fukuhara, and Keita Matsuno); AMED Research Program on Emerging and Re-emerging Infectious Diseases (JP21fk0108574, to Hesham Nasser; JP21fk0108493, to Takasuke Fukuhara; JP22fk0108617 to Takasuke Fukuhara; JP22fk0108146, to Kei Sato; JP21fk0108494 to G2P-Japan Consortium, Keita Matsuno, Shinya Tanaka, Terumasa Ikeda, Takasuke Fukuhara, and Kei Sato; JP21fk0108425, to Kazuo Takayama and Kei Sato; JP21fk0108432, to Kazuo Takayama, Takasuke Fukuhara and Kei Sato; JP22fk0108534, Terumasa Ikeda, and Kei Sato; JP22fk0108511, to Yuki Yamamoto, Terumasa Ikeda, Keita Matsuno, Shinya Tanaka, Kazuo Takayama, Takasuke Fukuhara, and Kei Sato; JP22fk0108506, to Kazuo Takayama and Kei Sato); AMED Research Program on HIV/AIDS (JP22fk0410055, to Terumasa Ikeda; and JP22fk0410039, to Kei Sato); AMED Japan Program for Infectious Diseases Research and Infrastructure (JP22wm0125008 to Keita Matsuno); AMED CREST (JP21gm1610005, to Kazuo Takayama; JP22gm1610008, to Takasuke Fukuhara; JST PRESTO (JPMJPR22R1, to Jumpei Ito); JST CREST (JPMJCR20H4, to Kei Sato); JSPS KAKENHI Fund for the Promotion of Joint International Research (International Leading Research) (JP23K20041, to G2P-Japan Consortium, Keita Matsuno, Takasuke Fukuhara and Kei Sato); JST SPRING (JPMJSP2108 to Shigeru Fujita); JSPS KAKENHI Grant-in-Aid for Scientific Research C (22K07103, to Terumasa Ikeda); JSPS KAKENHI Grant-in-Aid for Scientific Research B (21H02736, to Takasuke Fukuhara); JSPS KAKENHI Grant-in-Aid for Early-Career Scientists (22K16375, to Hesham Nasser; 20K15767, to Jumpei Ito); JSPS Core-to-Core Program (A. Advanced Research Networks) (JPJSCCA20190008, to Kei Sato); JSPS Research Fellow DC2 (22J11578, to Keiya Uriu); JSPS Research Fellow DC1 (23KJ0710, to Yusuke Kosugi); JSPS Leading Initiative for Excellent Young Researchers (LEADER) (to Terumasa Ikeda); World-leading Innovative and Smart Education (WISE) Program 1801 from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) (to Naganori Nao); Ministry of Health, Labour and Welfare (MHLW) under grant 23HA2010 (to Naganori Nao and Keita Matsuno); The Cooperative Research Program (Joint Usage/Research Center program) of Institute for Life and Medical Sciences, Kyoto University (to Kei Sato); International Joint Research Project of the Institute of Medical Science, the University of Tokyo (to Terumasa Ikeda and Takasuke Fukuhara); The Tokyo Biochemical Research Foundation (to Kei Sato); Takeda Science Foundation (to Terumasa Ikeda and Takasuke Fukuhara); Mochida Memorial Foundation for Medical and Pharmaceutical Research (to Terumasa Ikeda); The Naito Foundation (to Terumasa Ikeda); Hokuto Foundation for Bioscience (to Tomokazu Tamura); Hirose Foundation (to Tomokazu Tamura); and Mitsubishi Foundation (to Kei Sato).

New onset of hypomegakaryocytic thrombocytopenia with the potential for progression to aplastic anemia after BNT162b2 mRNA COVID-19 vaccination.

Vaccination with a coronavirus disease-2019 (COVID-19) vaccine is an effective public health measure for reducing the risk of infection and severe complications from COVID-19. However, serious hematological complications after COVID-19 vaccination have been reported. Here, we report a case of new-onset hypomegakaryocytic thrombocytopenia (HMT) with the potential for progression to aplastic anemia (AA) that developed in a 46-year-old man 4 days after the fourth mRNA COVID-19 vaccination. Platelet count rapidly decreased after vaccination and white blood cell count declined subsequently. Bone marrow examination immediately after disease onset showed severely hypocellular marrow (cellularity of almost 0%) in the absence of fibrosis, findings that were consistent with AA. Since the severity of pancytopenia did not meet the diagnostic criteria for AA, the patient was diagnosed with HMT that could progress to AA. Treatment with eltrombopag and cyclosporine was started immediately after diagnosis and cytopenia improved. Although it is difficult to determine whether the post-vaccination cytopenia was vaccine induced or accidental because the association was chronological, vaccination with an mRNA-based COVID-19 vaccine may be associated with development of HMT/AA. Therefore, physicians should be aware of this rare, but serious adverse event and promptly provide appropriate treatment.

Comparative pathogenicity of SARS-CoV-2 Omicron subvariants including BA.1, BA.2, and BA.5.

The unremitting emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants necessitates ongoing control measures. Given its rapid spread, the new Omicron subvariant BA.5 requires urgent characterization. Here, we comprehensively analyzed BA.5 with the other Omicron variants BA.1, BA.2, and ancestral B.1.1. Although in vitro growth kinetics of BA.5 was comparable among the Omicron subvariants, BA.5 was much more fusogenic than BA.1 and BA.2. Airway-on-a-chip analysis showed that, among Omicron subvariants, BA.5 had enhanced ability to disrupt the respiratory epithelial and endothelial barriers. Furthermore, in our hamster model, in vivo pathogenicity of BA.5 was slightly higher than that of the other Omicron variants and less than that of ancestral B.1.1. Notably, BA.5 gains efficient virus spread compared with BA.1 and BA.2, leading to prompt immune responses. Our findings suggest that BA.5 has low pathogenicity compared with the ancestral strain but enhanced virus spread /inflammation compared with earlier Omicron subvariants.

Convergent evolution of SARS-CoV-2 Omicron subvariants leading to the emergence of BQ.1.1 variant.

In late 2022, various Omicron subvariants emerged and cocirculated worldwide. These variants convergently acquired amino acid substitutions at critical residues in the spike protein, including residues R346, K444, L452, N460, and F486. Here, we characterize the convergent evolution of Omicron subvariants and the properties of one recent lineage of concern, BQ.1.1. Our phylogenetic analysis suggests that these five substitutions are recurrently acquired, particularly in younger Omicron lineages. Epidemic dynamics modelling suggests that the five substitutions increase viral fitness, and a large proportion of the fitness variation within Omicron lineages can be explained by these substitutions. Compared to BA.5, BQ.1.1 evades breakthrough BA.2 and BA.5 infection sera more efficiently, as demonstrated by neutralization assays. The pathogenicity of BQ.1.1 in hamsters is lower than that of BA.5. Our multiscale investigations illuminate the evolutionary rules governing the convergent evolution for known Omicron lineages as of 2022.

Virological characteristics of the SARS-CoV-2 XBB variant derived from recombination of two Omicron subvariants.

In late 2022, SARS-CoV-2 Omicron subvariants have become highly diversified, and XBB is spreading rapidly around the world. Our phylogenetic analyses suggested that XBB emerged through the recombination of two cocirculating BA.2 lineages, BJ.1 and BM.1.1.1 (a progeny of BA.2.75), during the summer of 2022. XBB.1 is the variant most profoundly resistant to BA.2/5 breakthrough infection sera to date and is more fusogenic than BA.2.75. The recombination breakpoint is located in the receptor-binding domain of spike, and each region of the recombinant spike confers immune evasion and increases fusogenicity. We further provide the structural basis for the interaction between XBB.1 spike and human ACE2. Finally, the intrinsic pathogenicity of XBB.1 in male hamsters is comparable to or even lower than that of BA.2.75. Our multiscale investigation provides evidence suggesting that XBB is the first observed SARS-CoV-2 variant to increase its fitness through recombination rather than substitutions.

Effect of adaptive servoventilation on muscle sympathetic nerve activity in patients with chronic heart failure and central sleep apnea.

BACKGROUND: Adaptive servoventilation (ASV) improves cardiac function and sympathetic nerve activity in patients with heart failure (HF). However, the mechanisms underlying these improvements remain obscure. METHODS AND RESULTS: We compared muscle sympathetic nerve activity (MSNA) and cardiorespiratory polygraphy and echocardiography findings at baseline and at 3.5 ± 0.8 months' follow-up in 32 patients with HF (New York Heart Association functional class II or III; ejection fraction <45%) and central sleep apnea (CSA; apnea-hypopnea index [AHI] ≥15/h) who consented (n = 20; ASV group) or declined (n = 12; non-ASV group) to undergo ASV treatment. Compliance with ASV and changes in AHI were determined from data collected by integral counters in devices and from cardiorespiratory polygraphic findings, respectively. Ejection fraction and MSNA significantly changed in the ASV (both P < .001) but not the non-ASV group. Although changes in AHI and MSNA correlated, the average use of ASV did not. In contrast, changes in AHI and the average use of ASV were independent predictors of changes in ejection fraction (both P < .01). CONCLUSIONS: ASV decreases MSNA and improves cardiac function in association with suppression of CSA in patients with HF.

Anticoagulation control quality affects the D-dimer levels of atrial fibrillation patients.

BACKGROUND: Anticoagulation control quality affects the incidence of thromboembolic events in atrial fibrillation (AF) patients. However, the effects of anticoagulation control quality on the prothrombotic state of AF patients are unclear. METHODS AND RESULTS: Ninety-five AF patients who had been treated with warfarin were prospectively followed-up for 449 ± 92 days. We analyzed whether time in the therapeutic range (TTR) of the international normalized ratio (INR) of prothrombin time, percentage of INR values in the range (%INR), and coefficient of variation of INR values (CV-INR) were related to D-dimer levels. The mean values of TTR, %INR, and CV-INR were 62%, 59%, and 0.19, respectively, and their median values were 67%, 63%, and 0.19, respectively. TTR was significantly correlated with %INR (R(2) = 0.917, P<0.01), but not with CV-INR (R(2) = 0.050, P = 0.26). The mean and median D-dimer levels were 0.79 and 0.60 µg/ml, respectively. Low TTR, low %INR, and high CV-INR were found to contribute to high D-dimer levels (P = 0.02, 0.03, and 0.02, respectively). CONCLUSIONS: In AF patients treated with warfarin, not only the duration outside the target INR range, but also the fluctuation in INR level may influence the prothrombotic state.

Protocol for a Sepsis Model Utilizing Fecal Suspension in Mice: Fecal Suspension Intraperitoneal Injection Model.

Background: Various animal models of sepsis have been developed to optimize sepsis treatment. However, therapeutic agents that were successful in animal models were rarely effective in human clinical trials. The cecal ligation and puncture (CLP) model is currently the gold standard for sepsis studies. However, its limitations include the high variability among researchers and the difficulty in comparing animals with different cecum shapes and sizes. In this study, we established a protocol for the creation of a simple and accessible sepsis rodent model using fecal suspensions that minimized differences in technical effects among researchers and individual differences in animals. Methods: A mouse model of sepsis using fecal suspension intraperitoneal injection (FSI) was created using fresh stool excreted within 24 h. The collected fresh stool was dissolved in saline solution and filtered. The obtained fecal suspension was injected intraperitoneally into the mice. Moreover, fecal suspensions with different concentrations were prepared, and the survival rates were compared among the fecal suspensions for each concentration. To assess the validity of the FSI as a sepsis model, CLP and FSI with similar mortality rates were compared pathologically, physiologically, immunologically, and bacteriologically. Histopathological comparison was evaluated by hematoxylin-eosin and Gram staining of the parenchymal organs. Physiological evaluation was performed by comparing the respiratory rate, body temperature, and blood gas analysis results. Immunological assessment was performed using multiplex analysis. Bacteriological comparisons were performed by culturing ascites fluid. Results: The FSI model increased mortality in proportion to the fecal suspension concentration. The mortality rate was reduced with antibiotic administration. In various comparative experiments conducted using the FSI and CLP models, both models showed findings consistent with sepsis. Furthermore, the FSI model showed less variability among the individuals in each test. Conclusion: This is the first detailed and accurate report of a protocol for creating a sepsis model using fecal suspension. The FSI model is a minimally invasive and accessible sepsis rodent model. Its clinical validity as a sepsis model was proven via histological, physiological, microbiological, and immunological evaluation methods. The FSI model minimizes individual differences between mice and helps to conduct accurate studies after the onset of sepsis.