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Background: More than 45 cases of transfusion‐transmitted hepatitis E virus infection (TT‐HEV) have been reported in Japan. Therefore, in 2020, universal individual donation nucleic acid amplification testing (ID‐NAT) was implemented for HEV. Study Design and Methods: We characterized HEV NAT‐positive blood donors. The number of new HEV infections and the asymptomatic infection rate were estimated using the HEV NAT‐positive rate. HEV RNA quantitation, phylogenetic analysis, and antibody tests were performed, and the residual risk of TT‐HEV was assessed based on the lookback study results. Results: A total of 5,075,100 blood donations were screened with ID‐NAT during the first year of implementation, among which 2804 (0.055%; males: 0.060%, females: 0.043%) were NAT‐positive with regional differences. Approximately 270,000 new HEV infection cases were estimated to occur annually in Japan, with an asymptomatic infection rate of 99.9%. The median HEV RNA concentration, excluding cases below the limit of quantification, was 205 IU/mL. Among the 1113 cases where the genotype could be determined, HEV‐3 and HEV‐4 accounted for 98.8% (1100) and 1.2% (13), respectively. The maximum duration of HEV viremia, including the pre‐ and post‐ID‐NAT window periods, was estimated to be 88.2 days. Within the 3 years since ID‐NAT implementation, no confirmed cases of breakthrough TT‐HEV were observed. Discussion: Multiple indigenous HEV strains are prevalent in Japan, infecting a significant number of individuals. However, since the implementation of ID‐NAT, TT‐HEV has been prevented due to the test's high sensitivity. [ABSTRACT FROM AUTHOR]

Background: The severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) essentially affects respiratory organs and tissues. SARS‐CoV‐2 RNAemia is often associated with more severe cases of coronavirus disease 2019 (COVID‐19) compared to cases without RNAemia. To determine the impact of the pandemic on transfusion medicine, particularly transfusion‐related infection, we examined the frequency of blood donation with RNAemia, the viral RNA (vRNA) concentration, and any possibility of transfusion‐transmitted infection (TTI) among transfusion recipients. Study Design and Methods: vRNA was examined in plasma/serum samples from 496 of 513 blood donors who reported having been infected with SARS‐CoV‐2 within 2 weeks of donation among a total of ca. 9.9 million blood donations in Japan between January 15, 2020, and December 31, 2021. The clinical course of patients transfused with the blood component containing vRNA was also examined. Results: vRNA was detected in 23 of 496 samples. The median period from blood donation to COVID‐19 onset was 1 day in 16 RNAemia‐positive donors. Most samples had vRNA concentrations below the limit of quantification. Three patients were transfused with either a packed red blood cell or platelet concentrate that tested positive for vRNA, showing no COVID‐19 symptoms and testing negative for vRNA in post‐transfusion blood. Conclusion: The rate of RNAemia was 4.6% among blood donors who were found to be infected with SARS‐CoV‐2 shortly after donation, and vRNA concentrations in their donated blood were extremely low. There was no evidence of TTI in the recipients transfused with RNAemia‐positive blood components. TTI risk in SARS‐CoV‐2 is negligible. [ABSTRACT FROM AUTHOR]

The incidence of hepatitis A virus (HAV) infection has declined significantly worldwide, including in Japan. A nationwide seroepidemiological study on hepatitis A in Japan has taken place almost every 10 years since 1973, and the last study was performed in 2003. In the present study, we describe the latest seroepidemiological pattern of hepatitis A in Japan using 7867 serum specimens obtained from healthy individuals collected between 2013 and 2017, approximately 10 years after the last study. Among them, 223 were anti‐HAV positive. About 68% of individuals aged 60 years and older had anti‐HAV antibodies, whereas only 1.1% of those aged below 60 years old had immunity; thus, almost all individuals younger than 60 years of age were HAV susceptible. In comparison with previous investigations, the susceptible population has increased and aged. According to data from the National Epidemiological Surveillance of Infectious Diseases (NESID) program, between 1989 and 2016, the proportion of patients with hepatitis A aged 60 years and older continuously increased with each year. The NESID data also suggested that recently, typical large foodborne outbreaks of hepatitis A have become rare, and cases tend to be reported among at‐risk groups; overseas travelers contributed to 25% of hepatitis A cases, and in 2018, the first nationwide hepatitis A outbreak that affected mostly men who have sex with men was reported. The purpose of this study was to determine the current status of HAV infection in Japan, based on both seroepidemiology and the national surveillance data from the NESID. [ABSTRACT FROM AUTHOR]

Hepatitis E virus (HEV) is a nonenveloped, singlestranded RNA virus belonging to the family Hepeviridae (1,2). In developing countries, HEV is a major cause of acute hepatitis, transmitted by the [...]

Characteristically, uterine myometrial cells (MCs) are proliferative, inducing angiogenesis within the female reproductive organ. We evaluated whether MCs implanted into myocardium could also induce angiogenesis and restore heart function after injury. MCs were isolated from the adult rat uterus and cultured for three studies: 1) Intracellular VEGF levels were measured in MCs cultured with progesterone ([10.sup.-11], [10.sup.-9], and [10.sup.-7] M) (n = 6 tests per group). 2) Blood vessel density was evaluated 8 days after MCs (3 x [10.sup.6] or 6 x [10.sup.6]), smooth muscle cells (SMCs), or endothelial cells (n = 6 rats per group) were injected with matrigel into the subcutaneous tissue of adult rats. 3) MCs, SMCs (5 x [10.sup.6]/rat), or media were injected into a transmural scar 3 wk after cryoinjury in rat hearts (n = 12 rats per group), and heart function, blood vessel density, and myocardial scar size and thickness were evaluated 5 wk later. In study 1, cultured MCs expressed VEGF, with levels significantly (P < 0.05) upregulated by progesterone at an optimal dose of [10.sup.-11] M. In study 2, MCs injected into the subcutaneous tissue with matrigel induced significantly more blood vessels, especially large-diameter vessels, than did SMCs or endothelial cells (P < 0.01 for all groups). This angiogenic effect was greatest (P < 0.01) at higher doses of MCs and was enhanced by progesterone ([10.sup.-11] M). In study 3, MCs implanted into the injured myocardium increased blood vessel density at the implant area, reduced scar size, and improved cardiac function relative to SMCs and media. Overall, MCs induced angiogenesis in vitro and in vivo, prevented cardiac remodeling, and improved heart functional recovery after cardiac injury. cell transplantation; heart failure; ischemic cardiomyopathy; angiogenic effect; heart function