The key to a successful pregnancy: a tamed immune reaction

The key to a successful pregnancy: a tamed immune reaction SAN FRANCISCO, CALIFORNIA—The riskiest moment in any human pregnancy is arguably when the fertilized egg attaches to the womb wall and tries to establish a lifeline between embryo and mother. About half of in vitro pregnancies fail during this implantation stage, and many natural pregnancies end then as well. Now, researchers comparing pregnancy in opossums and several other mammals have shown how precise control of an immune process, inflammation, is critical to success or failure.In work reported here last week at the annual meeting of the Society for Integrative and Comparative Biology, a Yale University team led by evolutionary developmental biologist Gunter Wagner found that so-called placental mammals have tweaked an ancient inflammatory process to enable embryos to implant and persist in the womb. Placental mammals—named for the mass of tissue in the uterus that serves as the interface between mother and fetus—have specialized uterine cells that suppress the release of a key immune-stimulating molecule. This suppression may help delay the rejection of the embryo until it’s fully mature, Arun Chavan, a Yale graduate student in Wagner’s lab, told the meeting.Beyond solving a key mystery about pregnancy, the work could also point to treatments for infertility and miscarriage, says Tom Stewart, an evolutionary developmental biologist at the University of Chicago in Illinois. “The more we understand about pregnancy in other species, the more likely it is that we can treat medical issues that arise during human pregnancy.” Sign up for our daily newsletterGet more great content like this delivered right to you!Country *AfghanistanAland IslandsAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelgiumBelizeBeninBermudaBhutanBolivia, Plurinational State ofBonaire, Sint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBrunei DarussalamBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongoCongo, The Democratic Republic of theCook IslandsCosta RicaCote D’IvoireCroatiaCubaCuraçaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland Islands (Malvinas)Faroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and Mcdonald IslandsHoly See (Vatican City State)HondurasHong KongHungaryIcelandIndiaIndonesiaIran, Islamic Republic ofIraqIrelandIsle of ManIsraelItalyJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKorea, Democratic People’s Republic ofKorea, Republic ofKuwaitKyrgyzstanLao People’s Democratic RepublicLatviaLebanonLesothoLiberiaLibyan Arab JamahiriyaLiechtensteinLithuaniaLuxembourgMacaoMacedonia, The Former Yugoslav Republic ofMadagascarMalawiMalaysiaMaldivesMaliMaltaMartiniqueMauritaniaMauritiusMayotteMexicoMoldova, Republic ofMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorwayOmanPakistanPalestinianPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarReunionRomaniaRussian FederationRWANDASaint Barthélemy Saint Helena, Ascension and Tristan da CunhaSaint Kitts and NevisSaint LuciaSaint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSamoaSan MarinoSao Tome and PrincipeSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSint Maarten (Dutch part)SlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia and the South Sandwich IslandsSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyrian Arab RepublicTaiwanTajikistanTanzania, United Republic ofThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited KingdomUnited StatesUruguayUzbekistanVanuatuVenezuela, Bolivarian Republic ofVietnamVirgin Islands, BritishWallis and FutunaWestern SaharaYemenZambiaZimbabweI also wish to receive emails from AAAS/Science and Science advertisers, including information on products, services and special offers which may include but are not limited to news, careers information & upcoming events.Required fields are included by an asterisk(*)Researchers have always puzzled over why the mother allows an embryo, which is basically a parasite, to settle in and grow. Yet implantation “was a critical first step in evolving pregnancy as humans experience it,” says Julia Bowsher, an integrative biologist at North Dakota State University in Fargo.This seeming paradox is even more perplexing because although a mother’s inflammatory reaction to this “parasite” is the biggest threat to pregnancy, it also seems necessary for the pregnancy to be successful, Wagner, Chavan, and Yale postdoc Oliver Griffith pointed out last year. A woman’s chance of implantation actually increases if her uterus has suffered mild trauma, for example by a uterine biopsy as part of an in vitro fertilization (IVF) procedure. Studies have shown that the IVF embryo is more likely to settle in, particularly at the biopsy site. Furthermore, an immune “rejection” response helps create the contractions necessary for a baby’s birth. Yet in between implantation and birth, the immune system is held in check, allowing the fetus to thrive.To understand the evolutionary basis for this interlude, Griffith recently led a study of gene activity in a marsupial, the gray short-tailed opossum (Monodelphis domestica). Marsupials have very short pregnancies. Early opossum embryos develop for about 12 days, enclosed as shelled eggs in the womb. They then shed their shells and try to attach to the uterine wall, activating placenta-promoting genes. But after about 2 days, the mother’s immune system “rejects” the embryos, causing the birth of a litter still at a very immature developmental stage compared with placental mammals. Griffith sampled opossum gene activity before pregnancy, during the egg-shell stage, and after implantation. The genes revealed the array of immune system signaling molecules and steroid hormones taking part in the immune attack on the embryo. The gene activity also pointed to a role for immune cells such as neutrophils, which launch a full-fledged inflammatory reaction, including the release of molecules that stimulate contractions of the uterus. The timing and makeup of this response largely mirror what is seen in implantation in placental mammals, indicating that process evolved in the common ancestor of placental and marsupial mammals, Griffith and colleagues reported 26 July 2017 in the Proceedings of the National Academy of Sciences.But later in evolution, placental mammals dialed back that inflammation to allow extended gestation. To find out how, Chavan compared implantation in the opossum with that in a range of placental mammals: rabbits, armadillos, and hyraxes, a 3-kilogram rodentlike mammal that’s closely related to elephants. Based on studies of gene activity and immune cells, he found that these mammals have “domesticated” implantation’s inflammatory response. At the implantation site, blood vessels proliferate in the uterine wall—the same hallmark of inflammation seen in the opossum—but the signaling molecule IL-17, which recruits neutrophils, is missing, Chavan reported at the meeting.Specialized cells called decidual cells seem to be responsible, he found. These cells form in the uterine lining early in pregnancy, and in mice and humans they persist through delivery. But in many other placental mammals, they disappear right after implantation. That suggests that in placental mammals, these cells might have evolved to switch the inflammatory response into low gear, Chavan says. Supporting that notion, he found in tissue studies that secretions of those cells could keep immune cells from making IL-17.“If that switch doesn’t happen, there are miscarriages,” says Gil Mor, a reproductive immunologist at Yale who was not involved with the work. “Understanding the evolution of decidual cells will be extremely helpful to those of us studying the nitty-gritty” of pregnancy. Opossums give birth to immature young because of an unchecked inflammatory reaction.  Oliver Griffith By Elizabeth PennisiJan. 10, 2018 , 4:50 PM

China to open visa office in Peshawar

Peshawar: China has decided to open a visa office in Peshawar to further boost economic relations with Pakistan. Chinese Ambassador to Pakistan Yao Jing announced this on Thursday after visiting ‘One Window Centre’ set up here by Chinese Embassy to provide an opportunity to the people to explore the culture of China. The centre provides people exposure to the Chinese culture, literature, art and history through exhibitions, movie screenings and training. Also Read – Saudi Crown Prince Salman ‘snubbed’ Pak PM Imran, recalled his private jet from US: Report The China Window Centre was inaugurated on October 1 last year. However, due to security threats, it was shut down and was re-inaugurated on January 2. Interacting with media after visiting the centre, Yao said the first small economic zone of China-Pakistan Economic Corridor (CPEC) in Rashakai in Khyber Pakhtunkhwa will be made operational this year and the development will help in poverty alleviation.

Torino’s Falque to miss derby

Torino winger Iago Falque is expected to miss the Derby della Mole against Juventus tomorrow with a muscular problem. reports Falque, who was all set to start, tweaked a muscle in training today and has been ruled out of the clash with Juve. The one-time Bianconeri player joins Tomas Rincon and Kevin Bonifazi on the sidelines, while Nicolas Nkoulou is also missing for Toro through suspension. The 29-year-old has struggled for form so far this season, playing six times without scoring or assisting. Watch Serie A live in the UK on Premier Sports for just £11.99 per month including live LaLiga, Eredivisie, Scottish Cup Football and more. Visit: