Perinatal outcomes after selective feticide via umbilical cord occlusion in complicated monochorionic pregnancies: A systematic review and meta-analysis.

OBJECTIVE: We aimed to compare perinatal outcomes between umbilical cord occlusion techniques in monochorionic pregnancies, including umbilical cord ligation, fetoscopic laser coagulation, interstitial laser coagulation, bipolar cord occlusion, radiofrequency ablation, and microwave ablation. METHODS: This study was registered with PROSPERO (CRD42020158861). PubMed, Web of Science, Cochrane Library, and Embase were searched for studies published up to May 2020. The DerSimonian-Laird random-effects model was used for the meta-analysis. Subgroup analyses were performed to compare the outcomes among the six techniques. Meta-regression was used to adjust for confounders. RESULTS: Thirty-four studies with 1646 participants were included. The overall survival was 76.5% after umbilical cord ligation, 78.8% after fetoscopic laser coagulation, 60.3% after interstitial laser coagulation, 79.2% after bipolar cord occlusion, 77.5% after radiofrequency ablation, and 75.0% after microwave ablation. Subgroup comparison showed the rates of overall survival and preterm premature rupture of membranes were not significant different among six techniques. However, rates of fetal loss, premature birth, live birth, and neonatal death differed significantly among the six groups. CONCLUSIONS: The choice of umbilical cord occlusion techniques will affect perinatal outcomes. We suggested that the choice of umbilical cord occlusion techniques should fully consider these differences among techniques.

Rethinking Remdesivir: Synthesis, Antiviral Activity, and Pharmacokinetics of Oral Lipid Prodrugs.

Remdesivir (RDV; GS-5734) is currently the only FDA-approved antiviral drug for the treatment of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The drug is approved for use in adults or children 12 years or older who are hospitalized for the treatment of COVID-19 on the basis of an acceleration of clinical recovery for inpatients with this disease. Unfortunately, the drug must be administered intravenously, restricting its use to those requiring hospitalization for relatively advanced disease. RDV is also unstable in plasma and has a complex activation pathway which may contribute to its highly variable antiviral efficacy in SARS-CoV-2-infected cells. Potent orally bioavailable antiviral drugs for early treatment of SARS-CoV-2 infection are urgently needed, and several, including molnupiravir and PF-07321332, are currently in clinical development. We focused on making simple, orally bioavailable lipid analogs of remdesivir nucleoside (RVn; GS-441524) that are processed to RVn monophosphate, the precursor of the active RVn triphosphate, by a single-step intracellular cleavage. In addition to high oral bioavailability, stability in plasma, and simpler metabolic activation, new oral lipid prodrugs of RVn had submicromolar anti-SARS-CoV-2 activity in a variety of cell types, including Vero E6, Calu-3, Caco-2, human pluripotent stem cell (PSC)-derived lung cells, and Huh7.5 cells. In Syrian hamsters, oral treatment with 1-O-octadecyl-2-O-benzyl-glycero-3-phosphate RVn (ODBG-P-RVn) was well tolerated and achieved therapeutic levels in plasma above the 90% effective concentration (EC90) for SARS-CoV-2. The results suggest further evaluation as an early oral treatment for SARS-CoV-2 infection to minimize severe disease and reduce hospitalizations.

Structural determination of the complement inhibitory domain of Borrelia burgdorferi BBK32 provides insight into classical pathway complement evasion by Lyme disease spirochetes.

The carboxy-terminal domain of the BBK32 protein from Borrelia burgdorferi sensu stricto, termed BBK32-C, binds and inhibits the initiating serine protease of the human classical complement pathway, C1r. In this study we investigated the function of BBK32 orthologues of the Lyme-associated Borrelia burgdorferi sensu lato complex, designated BAD16 from B. afzelii strain PGau and BGD19 from B. garinii strain IP90. Our data show that B. afzelii BAD16-C exhibits BBK32-C-like activities in all assays tested, including high-affinity binding to purified C1r protease and C1 complex, and potent inhibition of the classical complement pathway. Recombinant B. garinii BGD19-C also bound C1 and C1r with high-affinity yet exhibited significantly reduced in vitro complement inhibitory activities relative to BBK32-C or BAD16-C. Interestingly, natively produced BGD19 weakly recognized C1r relative to BBK32 and BAD16 and, unlike these proteins, BGD19 did not confer significant protection from serum killing. Site-directed mutagenesis was performed to convert BBK32-C to resemble BGD19-C at three residue positions that are identical between BBK32 and BAD16 but different in BGD19. The resulting chimeric protein was designated BXK32-C and this BBK32-C variant mimicked the properties observed for BGD19-C. To query the disparate complement inhibitory activities of BBK32 orthologues, the crystal structure of BBK32-C was solved to 1.7Å limiting resolution. BBK32-C adopts an anti-parallel four-helix bundle fold with a fifth alpha-helix protruding from the helical core. The structure revealed that the three residues targeted in the BXK32-C chimera are surface-exposed, further supporting their potential relevance in C1r binding and inhibition. Additional binding assays showed that BBK32-C only recognized C1r fragments containing the serine protease domain. The structure-function studies reported here improve our understanding of how BBK32 recognizes and inhibits C1r and provide new insight into complement evasion mechanisms of Lyme-associated spirochetes of the B. burgdorferi sensu lato complex.

SREBP2-dependent lipid gene transcription enhances the infection of human dendritic cells by Zika virus.

The emergence of Zika virus (ZIKV) as a global health threat has highlighted the unmet need for ZIKV-specific vaccines and antiviral treatments. ZIKV infects dendritic cells (DC), which have pivotal functions in activating innate and adaptive antiviral responses; however, the mechanisms by which DC function is subverted to establish ZIKV infection are unclear. Here we develop a genomics profiling method that enables discrete analysis of ZIKV-infected versus neighboring, uninfected primary human DCs to increase the sensitivity and specificity with which ZIKV-modulated pathways can be identified. The results show that ZIKV infection specifically increases the expression of genes enriched for lipid metabolism-related functions. ZIKV infection also increases the recruitment of sterol regulatory element-binding protein (SREBP) transcription factors to lipid gene promoters, while pharmacologic inhibition or genetic silencing of SREBP2 suppresses ZIKV infection of DCs. Our data thus identify SREBP2-activated transcription as a mechanism for promoting ZIKV infection amenable to therapeutic targeting.

Prevalence of mental health problems during the COVID-19 pandemic: A systematic review and meta-analysis.

BACKGROUND: The global COVID-19 pandemic has generated major mental and psychological health problems worldwide. We conducted a meta-analysis to assess the prevalence of depression, anxiety, distress, and insomnia during the COVID-19 pandemic. METHODS: We searched online biomedical databases (PubMed, Embase, Web of Science, Ovid, CNKI, and Wanfang Data) and preprint databases (SSRN, bioRxiv, and MedRxiv) for observational studies from January 1, 2020 to March 16, 2020 investigating the prevalence of mental health problems during the COVID-19 pandemic. RESULTS: We retrieved 821 citations from the biomedical databases and 53 citations from the preprint databases: 66 studies with 221,970 participants were included in our meta-analysis. The overall pooled prevalence of depression, anxiety, distress, and insomnia was 31.4%, 31.9%, 41.1% and 37.9%, respectively. Noninfectious chronic disease patients, quarantined persons, and COVID-19 patients had a higher risk of depression (Q=26.73, p<0.01) and anxiety (Q=21.86, p<0.01) than other populations. The general population and non-medical staff had a lower risk of distress than other populations (Q=461.21, p< 0.01). Physicians, nurses, and non-medical staff showed a higher prevalence of insomnia (Q=196.64, p<0.01) than other populations. LIMITATIONS: All included studies were from the early phase of the global pandemic. Additional meta-analyses are needed to obtain more data in all phases of the pandemic. CONCLUSIONS: The COVID-19 pandemic increases the mental health problems of the global population, particularly health care workers, noninfectious chronic disease patients, COVID-19 patients, and quarantined persons. Interventions for mental health are urgently needed for preventing mental health problems.

Rethinking Remdesivir: Synthesis, Antiviral Activity and Pharmacokinetics of Oral Lipid Prodrugs.

Remdesivir (RDV, GS-5734) is currently the only FDA-approved antiviral drug for the treatment of SARS CoV-2 infection. The drug is approved for use in adults or children 12-years or older who are hospitalized for the treatment of COVID-19 on the basis of an acceleration of clinical recovery for inpatients with this disease. Unfortunately, the drug must be administered intravenously, restricting its use to those requiring hospitalization for relatively advanced disease. RDV is also unstable in plasma and has a complex activation pathway which may contribute to its highly variable antiviral efficacy in SARS-CoV-2 infected cells. Potent orally bioavailable antiviral drugs for early treatment of SARS-CoV-2 infection are urgently needed and several including molnupiravir and PF-07321332 are currently in clinical development. We focused on making simple, orally bioavailable lipid analogs of Remdesivir nucleoside (RVn, GS-441524) that are processed to RVn-monophosphate, the precursor of the active RVn-triphosphate, by a single-step intracellular cleavage. In addition to high oral bioavailability, stability in plasma and simpler metabolic activation, new oral lipid prodrugs of RVn had submicromolar anti-SARS-CoV-2 activity in a variety of cell types including Vero E6, Calu-3, Caco-2, human pluripotent stem cell (PSC)-derived lung cells and Huh7.5 cells. In Syrian hamsters oral treatment with ODBG-P-RVn was well tolerated and achieved therapeutic levels in plasma above the EC90 for SARS-CoV-2. The results suggest further evaluation as an early oral treatment for SARS-CoV-2 infection to minimize severe disease and reduce hospitalizations.

Microwave ablation versus radiofrequency ablation for the treatment of severe complicated monochorionic pregnancies in China：protocol for a pilot randomised controlled trial.

INTRODUCTION: Complicated monochorionic twin pregnancies are often associated with high perinatal morbidity and mortality, some of which are severe enough to require a gestational reduction surgery to improve fetal survival and reduce disabilities. While radiofrequency ablation is currently the most commonly used procedure with higher fetal survival and fewer maternal and fetal complications compared with other surgical methods, the therapeutic effect of microwave ablation (MWA) is reported to be better, presumably due to the higher thermal effect and fewer restrictions. Currently there is limited evidence to prove the feasibility of MWA for selective reduction. The aim of this pilot study is to explore the feasibility, efficacy and safety of MWA reduction for severe complicated monochorionic pregnancies and may provide evidence for using the MWA in intrauterine surgeries extensively. METHODS AND ANALYSIS: This is a study protocol for a parallel-design pilot randomised controlled trial. 60 eligible patients with severe complicated monochorionic pregnancies will be randomised in a ratio of 1:1 to MWA group and radiofrequency group. Patients will be followed up until 6 months of age of the retained fetal. The primary analysis will compare the rates of neonatal survival at 28 days to evaluate the effect of MWA. The study will also evaluate the safety profile of MWA including the occurrence of postoperative adverse events and maternal and fetal complications. Additional secondary outcomes to be explored include the condition of neonatal asphyxia and the growth of surviving fetus at 6 months. Outcomes will be analysed by both a frequentist and the Bayesian statistical approach. ETHICS AND DISSEMINATION: This study was approved by the ethical review committee of the Peking University Third Hospital (Beijing, China). The results of this study will be published in peer-reviewed scientific journals and presented at relevant academic conferences. TRIAL REGISTRATION NUMBER: NCT04014452; Pre-results.

The Classical Complement Pathway Is Required to Control Borrelia burgdorferi Levels During Experimental Infection.

Activation of the classical complement pathway occurs to varying degrees within strains of the Borrelia burgdorferi sensu lato complex, which contain a group of pathogenic spirochetes that cause tick-borne Lyme borreliosis, including the agent of Lyme disease in the United States, B. burgdorferi. Despite this information, details related to the control of B. burgdorferi by the classical pathway are not clear. To address this question, we infected C1qα-/- mice, which cannot assemble the C1 complex and thus fail to activate the classical pathway, with B. burgdorferi sensu stricto strain B31. Using bioluminescent in vivo imaging, we found that C1qα-/- mice harbored more B. burgdorferi following 10 days of infection relative to their isogenic C57BL/6 parent. Quantitative PCR (qPCR) demonstrated that C1qα-/- mice harbored significantly more B. burgdorferi than parent mice did within lymph nodes, skin, heart, and joints. The increased B. burgdorferi load in C1qα-/- mice was observed at 21 and 28 days of infection, consistent with the classical pathway promoting complement-dependent, antibody-mediated killing following the development of a B. burgdorferi-specific humoral immune response. In addition, circulating borrelial-specific IgM was higher in C1qα-/- mice relative to their parent mouse strain and did not decrease at 21 and 28 days post-infection, indicating that IgG class switching was delayed in C1qα-/- mice. At day 28, both Borrelia-specific IgG1 and IgG3 levels were higher in infected C1qα-/- mice, but that these antibodies were not sufficient to control borrelial infection in the absence of the classical pathway. Furthermore, the lack of C1q also altered the balance of the Th1/Th2 response, as both circulating Th1 (MIP-1α, IL-2, IL-12, and TNFα), Th2 (IL-4, IL-10, and MCP-1), and Th17 (IL-17) cytokines were elevated in infected C1qα-/- mice. These data imply that C1q and the classical pathway play important roles in controlling borrelial infection via antibody and complement-dependent killing, as well as altering both antibody maturation processes and the T cell response following exposure to infectious B. burgdorferi.

Independent origins of resistance or susceptibility of parasitic wasps to a defensive symbiont.

Insect microbe associations are diverse, widespread, and influential. Among the fitness effects of microbes on their hosts, defense against natural enemies is increasingly recognized as ubiquitous, particularly among those associations involving heritable, yet facultative, bacteria. Protective mutualisms generate complex ecological and coevolutionary dynamics that are only beginning to be elucidated. These depend in part on the degree to which symbiont-mediated protection exhibits specificity to one or more members of the natural enemy community. Recent findings in a well-studied defensive mutualism system (i.e., aphids, bacteria, parasitoid wasps) reveal repeated instances of evolution of susceptibility or resistance to defensive bacteria by parasitoids. This study searched for similar patterns in an emerging model system for defensive mutualisms: the interaction of Drosophila, bacteria in the genus Spiroplasma, and wasps that parasitize larval stages of Drosophila. Previous work indicated that three divergent species of parasitic wasps are strongly inhibited by the presence of Spiroplasma in three divergent species of Drosophila, including D. melanogaster. The results of this study uncovered two additional wasp species that are susceptible to Spiroplasma and two that are unaffected by Spiroplasma, implying at least two instances of loss or gain of susceptibility to Spiroplasma among larval parasitoids of Drosophila.

Rapid spread of the defensive endosymbiont Spiroplasma in Drosophila hydei under high parasitoid wasp pressure.

Maternally transmitted endosymbionts of insects are ubiquitous in nature and play diverse roles in the ecology and evolution of their hosts. To persist in host lineages, many symbionts manipulate host reproduction to their advantage (e.g. cytoplasmic incompatibility and male-killing), or confer fitness benefits to their hosts (e.g. metabolic provisioning and defense against natural enemies). Recent studies suggest that strains of the bacterial genus Spiroplasma protect their host (flies in the genus Drosophila) against parasitoid attack. The Spiroplasma-conferred protection is partial and flies surviving a wasp attack have reduced adult longevity and fecundity. Therefore, it is unclear whether protection against wasps alone can counter Spiroplasma loss by imperfect maternal transmission and any possible fitness costs to harboring Spiroplasma. To address this question, we conducted a population cage study comparing Spiroplasma frequencies over time (host generations) under conditions of high wasp pressure and no wasp pressure. A dramatic increase of Spiroplasma prevalence was observed under high wasp pressure. In contrast, Spiroplasma prevalence in the absence of wasps did not change significantly over time; a pattern consistent with random drift. Thus, the defensive mechanism may contribute to the high prevalence of Spiroplasma in host populations despite imperfect vertical transmission.

Effect of the Drosophila endosymbiont Spiroplasma on parasitoid wasp development and on the reproductive fitness of wasp-attacked fly survivors.

In a previous study, we showed that Spiroplasma, a maternally transmitted endosymbiotic bacterium of Drosophila hydei, enhances larval to adult survival of its host when exposed to oviposition attack by the parasitoid wasp Leptopilina heterotoma. The mechanism by which Spiroplasma enhances host survival has not been elucidated. To better understand this mechanism, we compared the growth of wasp larvae in Spiroplasma-infected and uninfected hosts. Our results indicate that wasp embryos in Spiroplasma-infected hosts hatch and grow normally for ~2 days, after which their growth is severely impaired, compared to wasps developing in uninfected hosts. Thus, despite their reduced ability to complete development in Spiroplasma-infected hosts, developing wasps may exert fitness costs on their hosts that are manifested after host emergence. The severity of these costs will influence the degree to which this protective mechanism contributes to the long-term persistence of Spiroplasma in D. hydei. We therefore examined survival to 10-day-old adult stage and fecundity of Spiroplasma-infected flies surviving a wasp treatment. Our results suggest detrimental effects of wasp attack on longevity of Spiroplasma-infected adult flies. However, compared to Spiroplasma-free flies exposed to wasps, Spiroplasma-infected flies exposed to wasps have ~5 times greater survival from larva to 10 day-adult. The relative fecundity of wasp-attacked Spiroplasma-infected females was ~71% that of un-attacked Spiroplasma-free females. Our combined survival and female fecundity results suggest that under high wasp parasitism, the reproductive fitness of Spiroplasma-infected flies may be ~3.5 times greater than that of uninfected females, so it is potentially relevant to the persistence of Spiroplasma in natural populations of D. hydei. Interestingly, Spiroplasma-infected males surviving a wasp attack were effectively sterile during the 3-day period examined. This observation is consistent with the expectation that, as a maternally transmitted symbiont, there is little selective pressure on Spiroplasma to enhance the reproductive fitness of its male hosts.

Spiroplasma bacteria enhance survival of Drosophila hydei attacked by the parasitic wasp Leptopilina heterotoma.

BACKGROUND: Maternally-transmitted associations between endosymbiotic bacteria and insects are ubiquitous. While many of these associations are obligate and mutually beneficial, many are facultative, and the mechanism(s) by which these microbes persist in their host lineages remain elusive. Inherited microbes with imperfect transmission are expected to be lost from their host lineages if no other mechanisms increase their persistence (i.e., host reproductive manipulation and/or fitness benefits to host). Indeed numerous facultative heritable endosymbionts are reproductive manipulators. Nevertheless, many do not manipulate reproduction, so they are expected to confer fitness benefits to their hosts, as has been shown in several studies that report defense against natural enemies, tolerance to environmental stress, and increased fecundity. METHODOLOGY/PRINCIPAL FINDINGS: We examined whether larval to adult survival of Drosophila hydei against attack by a common parasitoid wasp (Leptopilina heterotoma), differed between uninfected flies and flies that were artificially infected with Spiroplasma, a heritable endosymbiont of Drosophila hydei that does not appear to manipulate host reproduction. Survival was significantly greater for Spiroplasma-infected flies, and the effect of Spiroplasma infection was most evident during the host's pupal stage. We examined whether or not increased survival of Spiroplasma-infected flies was due to reduced oviposition by the wasp (i.e., pre-oviposition mechanism). The number of wasp eggs per fly larva did not differ significantly between Spiroplasma-free and Spiroplasma-infected fly larvae, suggesting that differential fly survival is due to a post-oviposition mechanism. CONCLUSIONS/SIGNIFICANCE: Our results suggest that Spiroplasma confers protection to D. hydei against wasp parasitism. This is to our knowledge the first report of a potential defensive mutualism in the genus Spiroplasma. Whether it explains the persistence and high abundance of this strain in natural populations of D. hydei, as well as the widespread distribution of heritable Spiroplasma in Drosophila and other arthropods, remains to be investigated.