Early-stage mammalian embryos develop in a low O2 environment (hypoxia). hES cells, however, are generally cultured under an atmosphere of 21% O2 (normoxia), under which conditions they tend to differentiate spontaneously. Such conditions may not be the most suitable, therefore, for hES cell propagation. Here we have tested two hypotheses. The first hypothesis was that hES cells would grow as well under hypoxic as under normoxic conditions. The second hypothesis was that hypoxic culture would reduce the amount of spontaneous cell differentiation that occurs in hES colonies. Both hypotheses proved to be correct. Cells proliferated as well under 3% and 5% O2 as they did under 21% O2, and growth was only slightly reduced at 1% O2. The appearance of differentiated regions as assessed morphologically, biochemically (by the production of human chorionic gonadotropin and progesterone), and immunohistochemically (by the loss of stage-specific embryonic antigen-4 and Oct-4 and gain of stage-specific embryonic antigen-1 marker expression) was markedly reduced under hypoxic conditions. In addition, hES cell growth under hypoxia provided enhanced formation of embryoid bodies. Hypoxic culture would appear to be necessary to maintain full pluripotency of hES cells.H1 cell ͉ hypoxia ͉ pluripotent ͉ human chorionic gonadotropin ͉ Oct-4 transcription factor

BackgroundThe extent to which reproductive tract infections (RTIs) are associated with poor menstrual hygiene management (MHM) practices has not been extensively studied. We aimed to determine whether poor menstrual hygiene practices were associated with three common infections of the lower reproductive tract; Bacterial vaginosis (BV), Candida, and Trichomonas vaginalis (TV).MethodsNon-pregnant women of reproductive age (18–45 years) and attending one of two hospitals in Odisha, India, between April 2015 and February 2016 were recruited for the study. A standardized questionnaire was used to collect information on: MHM practices, clinical symptoms for the three infections, and socio-economic and demographic information. Specimens from posterior vaginal fornix were collected using swabs for diagnosis of BV, Candida and TV infection.ResultsA total of 558 women were recruited for the study of whom 62.4% were diagnosed with at least one of the three tested infections and 52% presented with one or more RTI symptoms. BV was the most prevalent infection (41%), followed by Candida infection (34%) and TV infection (5.6%). After adjustment for potentially confounding factors, women diagnosed with Candida infection were more likely to use reusable absorbent material (aPRR = 1.54, 95%CI 1.2–2.0) and practice lower frequency of personal washing (aPRR = 1.34, 95%CI 1.07–1.7). Women with BV were more likely to practice personal washing less frequently (aPRR = 1.25, 95%CI 1.0–1.5), change absorbent material outside a toilet facility (aPRR = 1.21, 95%CI 1.0–1.48) whilst a higher frequency of absorbent material changing was protective (aPRR = 0.56, 95%CI 0.4–0.75). No studied factors were found to be associated with TV infection. In addition, among women reusing absorbent material, Candida but not BV or TV - infection was more frequent who dried their pads inside their houses and who stored the cloth hidden in the toilet compartment.ConclusionThe results of our study add to growing number of studies which demonstrate a strong and consistent association between poor menstrual hygiene practices and higher prevalence of lower RTIs.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-3384-2) contains supplementary material, which is available to authorized users.

To realize the full potential of human embryonic stem cells (hESCs), it is important to develop culture conditions that maintain hESCs in a pluripotent, undifferentiated state. A low O(2) atmosphere (approximately 4% O(2)), for example, prevents spontaneous differentiation and supports self-renewal of hESCs. To identify genes whose expression is sensitive to O(2) conditions, microarray analysis was performed on RNA from hESCs that had been maintained under either 4% or 20% O(2). Of 149 genes differentially expressed, 42 were up-regulated and 107 down-regulated under 20% O(2). Several of the down-regulated genes are most likely under the control of hypoxia-inducing factors and include genes encoding enzymes involved in carbohydrate catabolism and cellular redox state. Although genes associated with pluripotency, including OCT4, SOX2, and NANOG were generally unaffected, some genes controlled by these transcription factors, including LEFTY2, showed lowered expression under 20% O(2), while a few genes implicated in lineage specification were up-regulated. Although the differences between O(2) conditions were generally subtle, they were observed in two different hESC lines and at different passage numbers. The data are consistent with the hypothesis that 4% O(2) favors the molecular mechanisms required for the maintenance of pluripotency.

In sepsis, several cell types (e.g., lymphocytes) undergo apoptosis and have the potential to harm the host if not cleared by professional phagocytes. Apoptotic cells display "eat me" signals such as phosphatidylserine that can be readily recognized by phagocytes. For full engulfment of these cells, binding to integrin alpha(v)beta(3), mediated by the bridging protein, milk fat globule epidermal growth factor-factor VIII (MFG-E8), is necessary. We hypothesized that, in sepsis, phagocytosis of apoptotic cells is impaired due to decreased MFG-E8 expression and that adoptive transfer of exosomes containing MFG-E8 is beneficial. Sepsis was induced in rats by cecal ligation and puncture (CLP) and MFG-E8 expression assessed by Western blot 20 h later. Dendritic cells were generated from bone marrow cells, and secreted exosomes were collected and injected into CLP animals. Plasma cytokines (enzyme-linked immunosorbent assay) and thymocyte apoptosis (TC-Ao, annexin V) were assessed. The ability of peritoneal macrophages from septic animals to engulf apoptotic cells was determined in an ex vivo phagocytosis assay. A 10-day survival study was conducted. Cecal ligation and puncture reduced MFG-E8 protein levels in the spleen and liver by 48% and 70%, respectively, and increased TC-Ao by 1.6-fold. Injection of MFG-E8-containing exosomes, however, led to a 33% reduced detection of TC-Ao, without directly inhibiting apoptosis. In fact, peritoneal macrophages from exosome-treated rats displayed a 2.8-fold increased ability to phagocytose apoptotic thymocytes. Inhibition of MFG-E8 before injection of exosomes completely abrogated the enhanced phagocytosis. Treatment with bone marrow dendritic cell-derived exosomes also reduced plasma tumor necrosis factor alpha and interleukin (IL)-6 levels and improved survival from 44% to 81%. We conclude that, by providing the indispensable factor MFG-E8 for complete engulfment of apoptotic cells, these exosomes lead to an attenuation of the systemic inflammatory response and overall beneficial effect in sepsis.