Atovaquone Inhibits Arbovirus Replication through the Depletion of Intracellular Nucleotides.

Arthropod-borne viruses represent a significant public health threat worldwide, yet there are few antiviral therapies or prophylaxes targeting these pathogens. In particular, the development of novel antivirals for high-risk populations such as pregnant women is essential to prevent devastating disease such as that which was experienced with the recent outbreak of Zika virus (ZIKV) in the Americas. One potential avenue to identify new and pregnancy-acceptable antiviral compounds is to repurpose well-known and widely used FDA-approved drugs. In this study, we addressed the antiviral role of atovaquone, an FDA Pregnancy Category C drug and pyrimidine biosynthesis inhibitor used for the prevention and treatment of parasitic infections. We found that atovaquone was able to inhibit ZIKV and chikungunya virus virion production in human cells and that this antiviral effect occurred early during infection at the initial steps of viral RNA replication. Moreover, we were able to complement viral replication and virion production with the addition of exogenous pyrimidine nucleosides, indicating that atovaquone functions through the inhibition of the pyrimidine biosynthesis pathway to inhibit viral replication. Finally, using an ex vivo human placental tissue model, we found that atovaquone could limit ZIKV infection in a dose-dependent manner, providing evidence that atovaquone may function as an antiviral in humans. Taken together, these studies suggest that atovaquone could be a broad-spectrum antiviral drug and a potential attractive candidate for the prophylaxis or treatment of arbovirus infection in vulnerable populations, such as pregnant women and children.IMPORTANCE The ability to protect vulnerable populations such as pregnant women and children from Zika virus and other arbovirus infections is essential to preventing the devastating complications induced by these viruses. One class of antiviral therapies may lie in known pregnancy-acceptable drugs that have the potential to mitigate arbovirus infections and disease, yet this has not been explored in detail. In this study, we show that the common antiparasitic drug atovaquone inhibits arbovirus replication through intracellular nucleotide depletion and can impair ZIKV infection in an ex vivo human placental explant model. Our study provides a novel function for atovaquone and highlights that the rediscovery of pregnancy-acceptable drugs with potential antiviral effects can be the key to better addressing the immediate need for treating viral infections and preventing potential birth complications and future disease.

Dengue Virus Immunity Increases Zika Virus-Induced Damage during Pregnancy.

Zika virus (ZIKV) has recently been associated with birth defects and pregnancy loss after maternal infection. Because dengue virus (DENV) and ZIKV co-circulate, understanding the role of antibody-dependent enhancement in the context of pregnancy is critical. Here, we showed that the presence of DENV-specific antibodies in ZIKV-infected pregnant mice significantly increased placental damage, fetal growth restriction, and fetal resorption. This was associated with enhanced viral replication in the placenta that coincided with an increased frequency of infected trophoblasts. ZIKV-infected human placental tissues also showed increased replication in the presence of DENV antibodies, which was reversed by FcγR blocking antibodies. Furthermore, ZIKV-mediated fetal pathogenesis was enhanced in mice in the presence of a DENV-reactive monoclonal antibody, but not in the presence of the LALA variant, indicating a dependence on FcγR engagement. Our data suggest a possible mechanism for the recent increase in severe pregnancy outcomes after ZIKV infection in DENV-endemic areas.

Distinct epigenetic programs regulate cardiac myocyte development and disease in the human heart in vivo.

Epigenetic mechanisms and transcription factor networks essential for differentiation of cardiac myocytes have been uncovered. However, reshaping of the epigenome of these terminally differentiated cells during fetal development, postnatal maturation, and in disease remains unknown. Here, we investigate the dynamics of the cardiac myocyte epigenome during development and in chronic heart failure. We find that prenatal development and postnatal maturation are characterized by a cooperation of active CpG methylation and histone marks at cis-regulatory and genic regions to shape the cardiac myocyte transcriptome. In contrast, pathological gene expression in terminal heart failure is accompanied by changes in active histone marks without major alterations in CpG methylation and repressive chromatin marks. Notably, cis-regulatory regions in cardiac myocytes are significantly enriched for cardiovascular disease-associated variants. This study uncovers distinct layers of epigenetic regulation not only during prenatal development and postnatal maturation but also in diseased human cardiac myocytes.

Late termination of pregnancy for lethal fetal anomalies: a national survey of maternal-fetal medicine specialists.

OBJECTIVE: The objective was to ascertain the practices and opinions of US maternal-fetal medicine specialists regarding termination of pregnancy as a management option following late diagnosis of lethal fetal anomalies. STUDY DESIGN: We conducted a cross-sectional mail survey of all US members of the Society of Maternal Fetal Medicine to ascertain how they manage pregnancies diagnosed with lethal fetal anomalies after 24 weeks of gestation. We analyzed the proportion of respondents that discuss termination of pregnancy as a management option, barriers to offering or accessing late termination services, and respondents' opinions about what anomalies are lethal and when pregnancy termination should be permitted. RESULTS: The response rate was 41% (869/2119). Nearly all (93%) respondents discuss delivery near term or when complications arise, while 75% discuss the option of termination of pregnancy soon after the diagnosis of lethal fetal anomalies. Only 52% of the physicians indicated that their patients could obtain termination of pregnancy after 24 weeks at their affiliated medical centers or through providers within 50 miles. Real or perceived legal restrictions represented the most common reason for lack of local services. The proportion of respondents that felt strongly or very strongly that termination of pregnancy should be allowed was 76% for lethal anomalies and 58% for anomalies likely to result in significant long-term impairment. CONCLUSION: Although limited by a modest response rate, our study found that physicians do not consistently discuss immediate termination of pregnancy as an option following late diagnosis of lethal fetal anomalies, and they face numerous barriers to providing these services. IMPLICATIONS: This national survey supports the need for improved services for pregnant women who desire later termination of pregnancy following diagnosis of serious fetal anomalies. Helpful efforts might include educating physicians about the laws and regulations governing late termination of pregnancy, forging more consistent standards of care, and improving collaboration between MFM specialists and family planning providers to enhance access to care.

Safety of digoxin for fetal demise before second-trimester abortion by dilation and evacuation.

BACKGROUND: Digoxin is used to induce fetal demise before dilation and evacuation (D&E) abortion. Published data on the safety of digoxin in abortion care are limited. STUDY DESIGN: We conducted a retrospective cohort study with historical controls at a large family planning center. We reviewed the records of patients at 18 to 24 weeks' gestation who received digoxin before D&E from May 15, 2007 (date the center initiated digoxin use), through March 31, 2008. We also reviewed the records of patients who presented for D&E without digoxin from February 22, 2006, through May 12, 2007. We compared the rates of immediate complications. RESULTS: We included 566 digoxin patients and 513 controls. Eleven spontaneous abortions occurred in the digoxin cohort; none occurred among controls (p<.001). We found 19 cases of infection in the digoxin cohort and three among controls (odds ratio 5.91; 95% confidence interval 1.74-20.07). Eleven digoxin patients were admitted to a hospital after the preoperative visit; no controls were admitted (p<.001). CONCLUSIONS: Patients who received digoxin before D&E were more likely to experience spontaneous abortion, infection and hospital admission than controls who underwent D&E without digoxin.

The safety of deep sedation without intubation for abortion in the outpatient setting.

STUDY OBJECTIVE: To determine the rate of perioperative pulmonary aspiration in patients undergoing first and second-trimester surgical abortion during deep sedation with propofol, without intubation. DESIGN: Retrospective review of cases of surgical and anesthetic complications reported to the Office of Quality Management of the surgical facility between August 1, 2001 and April 30, 2008. SETTING: Large urban surgical abortion outpatient facility. MEASUREMENTS: The medical records of all surgical abortion patients who underwent hospital transfer were reviewed. From billing records, all patients who underwent abortion during deep sedation were identified. The primary outcome was the rate of perioperative pulmonary aspiration. Secondary outcomes included the rates of other anesthesia-related adverse events resulting in hospital transfer. MAIN RESULTS: During the 81-month study period, the facility performed 62,125 surgical abortions during deep sedation, including 11,039 second-trimester abortions. Only one patient received endotracheal intubation. No cases of perioperative pulmonary aspiration occurred. CONCLUSIONS: Deep sedation without intubation is a viable method of anesthesia for both first and second-trimester surgical abortions in the outpatient setting.

Genomic loss of imprinting in first-trimester human placenta.

OBJECTIVE: The purpose of this study was to investigate imprinting patterns in first-trimester human placentas. STUDY DESIGN: Using samples of 17 first-trimester and 14 term placentas from uncomplicated pregnancies, we assessed loss of imprinting (LOI) at the RNA level in a panel of 14 genes that are known to be imprinted in the placenta with the use of a quantitative allele-specific reverse transcriptase polymerase chain reaction analysis of those genes that contained readout single nucleotide polymorphisms in their transcripts. RESULTS: There is significant LOI (ie, biallelic expression) in all 14 genes in first-trimester placentas. LOI was more variable and generally at lower levels at term. Although there is little difference in gene expression, the level of LOI is higher in the first-trimester placentas, compared with term placentas. CONCLUSION: Genomic imprinting appears to be a dynamic maturational process across gestation in human placenta. In contrast with prevailing theories, epigenetic imprints may continue to evolve past 12 weeks of gestation.

Introducing abortion patients to a culture of support: a pilot study.

Currently in the United States, women who have abortions face a societal culture in which disapproval, stigma, and misinformation about the risks and sequelae of abortion are common. The purpose of this study is to pilot test an intervention that introduces abortion patients to a "culture of support" by providing validating messages and information about groups and services that support women in their reproductive decisions, addressing stigma, and providing information to help women identify and avoid sources of abortion misinformation. Twenty-two women who completed their post-operative exam after abortion were enrolled to take part in the study intervention. In-depth interviews were conducted to explore patient experiences and responses to the intervention. All (22/22) participants responded that they believed that interventions like the one studied could help women avoid letting the judgmental actions and attitudes of others "get to them so much". All (20/20) participants felt that the intervention was personally helpful to them. An intervention that introduces women having abortions to a "culture of support" was well-received. This study provides a framework for future research about the content, strength, and effect of societal and cultural influences on women having abortions and for additional research about interventions to promote resilience after abortion.

Activation of CD8+ regulatory T cells by human placental trophoblasts.

The immunological basis by which a mother tolerates her semi-allogeneic fetus remains poorly understood. Several mechanisms are likely to contribute to this phenomenon including active immune regulation by regulatory T cells. In this article, we report that human placental trophoblasts activate a clonal population of CD8(+) T cells with regulatory function. These cells are not MHC class I restricted, but require costimulation through a member of the carcinoembryonic Ag family present on early gestation trophoblasts. These regulatory T cells express the mucosal markers CD101 and CD103 and display selective usage of the TCR gene Vbeta9. CD8(+) T cells isolated from the peripheral blood of pregnant mothers (16-28 wk) also demonstrate expansions in the same Vbeta family (Vbeta9), signaling a possible role for these cells in preventing fetal rejection in vivo. We have previously characterized a subset of CD8(+) regulatory T cells activated by the combination of the nonclassical class I molecule CD1d and a costimulatory molecule of the carcinoembryonic Ag family present on the intestinal epithelium. These data support the concept that distinct regulatory T cell populations exist at different sites and may be regulated locally by unique restriction elements, costimulatory signals, and Ags.