A multistate stem cell dynamics maintains homeostasis in mouse spermatogenesis.

In mouse testis, a heterogeneous population of undifferentiated spermatogonia (Aundiff) harbors spermatogenic stem cell (SSC) potential. Although GFRα1+ Aundiff maintains the self-renewing pool in homeostasis, the functional basis of heterogeneity and the implications for their dynamics remain unresolved. Here, through quantitative lineage tracing of SSC subpopulations, we show that an ensemble of heterogeneous states of SSCs supports homeostatic, persistent spermatogenesis. Such heterogeneity is maintained robustly through stochastic interconversion of SSCs between a renewal-biased Plvap+/GFRα1+ state and a differentiation-primed Sox3+/GFRα1+ state. In this framework, stem cell commitment occurs not directly but gradually through entry into licensed but uncommitted states. Further, Plvap+/GFRα1+ cells divide slowly, in synchrony with the seminiferous epithelial cycle, while Sox3+/GFRα1+ cells divide much faster. Such differential cell-cycle dynamics reduces mitotic load, and thereby the potential to acquire harmful de novo mutations of the self-renewing pool, while keeping the SSC density high over the testicular open niche.

A retrospective observational study of the treatment of a nosocomial infection caused by oseltamivir-resistant influenza virus A with baloxavir marboxil.

BACKGROUND: Nosocomial (hospital-acquired) influenza A virus infection is a very important clinical issue. The objective of this study is to describe the effect of baloxavir marboxil in controlling an outbreak of this infection. METHODS: A retrospective observational study was performed to assess the effectiveness of baloxavir marboxil in the treatment of nosocomial infections caused by oseltamivir-resistant influenza virus A. RESULTS: In September 2019, there was an outbreak of nosocomial influenza A(H1N1)pdm09 viral infection in one out of three facility wards for inpatients at the Okinawa Nanbu Regional Center for Children with Special Needs. Symptomatic staff members were kept off duty until they remained afebrile for 2 days. Prophylactic oseltamivir was administered to inpatients (n = 37) and to staff members (n = 16) who voluntarily requested the drug. However, both inpatients and staff members showed influenza A infection during prophylactic use of oseltamivir. The A(H1N1)pdm09 virus sample obtained from one patient was shown to be oseltamivir-resistant. After administration of baloxavir marboxil, the nosocomial outbreak gradually ceased. Moreover, the time (hours) to alleviation of fever in the oseltamivir group (n = 11) and baloxavir marboxil group (n = 13) was significantly different (p = 0.0034). CONCLUSION: Our report provides evidence for the usefulness of baloxavir marboxil in treating influenza A patients who have received prophylactic doses of oseltamivir. This is the first report describing the successful use of baloxavir marboxil for of a nosocomial outbreak caused by oseltamivir-resistant influenza A virus.

Histological effects and pharmacokinetics of lipopolysaccharide derived from Porphyromonas gingivalis on rat maxilla and liver concerning with progression into non-alcoholic steatohepatitis.

BACKGROUND: Non-alcoholic steatohepatitis (NASH) is one of the chronic liver diseases that can develop into hepatocirrhosis. The purpose of the present study was to investigate the impact of lipopolysaccharide (LPS) from Porphyromonas gingivalis (P. gingivalis) on NASH onset, and to determine the biodistribution of double-radiolabeled LPS (R-LPS) biosynthesized in P. gingivalis. METHODS: Rats fed a basal diet (BD) or a high-fat diet (HD) were injected with P. gingivalis-LPS or R-LPS into the palatine gingiva around the right maxillary first molar, and were classified into the following 4 groups: BD/LPS (-), BD/LPS (+), HD/LPS (-), and HD/LPS (+) or 2 groups: BD/R-LPS and HD/R-LPS. RESULTS: Inflammation in the gingiva of the LPS (+) groups progressed significantly more than the LPS (-) groups. Furthermore, in the HD/LPS (+) liver, histologic analysis confirmed the presence of NASH, characterized by large fat droplets, ballooning degeneration, and infiltration of inflammatory cells. When 3 H, 14 C-R-LPS was injected into the palatine gingiva, radioactivity in the right palatal mucosa of HD/R-LPS rats was the highest in comparison with other regions and was significantly elevated after 24 hours compared to BD/R-LPS rats. Autoradiographic analysis of the maxilla showed distributions from the palatal mucosa to the hard palate and the interdental region. Radioactivity in organs of both BD/R-LPS and HD/R-LPS rats were mostly localized to the liver even after 24 hours. CONCLUSION: The present study suggests that the transfer of P. gingivalis-LPS from the oral cavity to the liver plays an important role in disease exacerbation of NASH.

Effects of experimental periodontitis on the metabolic system in rats with diet-induced obesity (DIO): an analysis of serum biochemical parameters.

Recent studies have shown that periodontitis accelerates the progression of obesity-associated metabolic diseases. Thus, we examined the influence of periodontitis on serum biochemical parameters of metabolic disease in a diet-induced obesity (DIO) rat. First, we established the DIO model using ten male rats fed with either basal diet (lean group) or high-fat diet (DIO group) for 12 weeks. Second, to examine the interaction between periodontitis and obesity, we divided 24 DIO rats into the following four groups. (1) Porphyromonas gingivalis (Pg) group was applied with Pg around the maxillary first molar (M1). (2) Ligature group was applied with ligature placement around M1. (3) Ligature/Pg group was treated with both ligature placement and Pg. (4) Control was non-treatment group. Serum biochemical parameters and maxillary histopathology were evaluated at 12 weeks. The DIO model demonstrated significant increases in body weight, serum insulin, alanine aminotransaminase (ALT) levels, and insulin resistance (HOMA-IR) compared to the lean group. In the DIO ligature and ligature/Pg groups, alveolar bone resorption and inflammatory cell infiltration were significantly increased compared to the control. Serum levels of fasting glucose, lactate dehydrogenase, and uric acid were also significantly higher, while the liver damage markers ALT and aspartate aminotransferase were only higher in ligature/Pg group. However, we observed no significant differences between the Pg group and Control. The present study suggested a possibility that periodontitis induced by ligature placement changed serum metabolic parameter regarding organs such as the liver in DIO rat.

Porphyromonas gingivalis induced periodontitis exacerbates progression of non-alcoholic steatohepatitis in rats.

Non-alcoholic steatohepatitis (NASH) is a chronic liver disease that can develop into hepatocirrhosis and hepatic carcinoma. In recent years, epidemiological and animal studies have reported that Porphyromonas gingivalis (P. gingivalis), a known periodontopathic bacteria, is closely related to NASH. However, previous studies could not demonstrate a direct relationship between periodontitis, P. gingivalis infection, and NASH. The purpose of the present study was to examine the impact of P. gingivalis-associated periodontitis on the onset and progression of NASH. Forty-two male Wistar rats were used in this study. Rats were fed a high-fat diet (HFD) for 12 weeks in order to induce fatty liver. At 4 weeks from the start of feeding, the animals were performed ligature placement around the maxillary first molar tooth in order to induce experimental periodontitis, and then a P. gingivalis slurry was applied around the ligature twice in a week for 8 weeks (HFD/Pg(+) group). Controls were given the slurry without P. gingivalis after ligature placement using the same protocol (HFD/Pg(-) group). Significant increases in alveolar bone resorption and inflammation in periodontal tissue around the molar tooth in the HFD/Pg(+) group were observed when compared with the HFD/Pg(-) group. Moreover, histological images showing NASH characterized by perivenular lipid deposition including big fatty drops, ballooning degeneration, and focal necrosis with inflammatory cells were confirmed in the liver of rats in the HFD/Pg(+) group. Significant increases in alanine aminotransaminase, aspartate aminotransferase, and C-reactive protein levels were observed in the HFD/Pg(+) group. Furthermore, endotoxin levels in serum in the HFD/Pg(+) group were significantly higher than those in the HFD/Pg(-) group. The present study demonstrated that experimental periodontitis induced by P. gingivalis led to the progression of NASH in rats with fatty liver. Increased levels of endotoxin derived from P. gingivalis infection appear to play a considerable role in the progression of NASH.