分娩方式和肠道菌群对后代超重的影响
超重或肥胖可从母亲传递给孩子，其背后的风险因素有哪些？JAMA Pediatrics[IF：10.251]本周上线了来自加拿大的研究，对近千名婴儿进行了追踪分析，发现剖腹产和婴儿期（平均3.7月龄）肠道菌群中毛螺菌科的丰度，是超重和肥胖跨代传递的重要风险因素。或许可以推测，孕期肥胖和剖腹产可影响婴儿的肠道菌群，从而增加后代的肥胖风险，不过，这些仍需更多研究验证，对其中机制的研究或有助于对肥胖的预防。
论文摘要
Childhood obesity is aglobal health concern.1,2 More than 20% of preschool-aged children inCanada are over-weight or obese (OWOB). Also on the rise is maternal OWOBduring pregnancy4-6 and associated higher rates of birth by cesarean delivery.6-8 Furthermore, carrying OWOBinto preg- nancy presents, at minimum, a 2-fold greater risk of obesity inoffspring.7,9,10 Someof this excess risk can be attributed to cesarean delivery, as childrendelivered by this method are 30% more likely to develop OWOB compared withthose delivered vaginally.11 However, while the epidemiologic evidence isstrong that prenatal maternal obesity predisposes newborns to develop OWOB, themechanism behind this intergenera- tional association has not, to ourknowledge, been delineated by known genetic or lifestyle factors shared betweenmoth- ers and their offspring.12
Mother-to-newborn transferof obesogenic microbes has been put forward as a biological pathway for theintergenera- tional transmission of OWOB.13 Substantial changes to thein- testinal microbiota of women are observed as pregnancy pro- gresses toparturition.14,15 Theweight status of women entering pregnancy can modify this process. Comparedwith their nor- mal-weight counterparts, women with a high prepregnancy bodymass index (BMI) have elevated levels of Bacteroides in their third trimester.16 Because maternal microbiotaare the pri- mary source for the first inoculation of newborn infants17 and microbiota have beenimplicated in adipogenesis,18,19 it is con- ceivable that prepregnancy weight andthe maternal intesti- nal microbiome influence microbial assembly in the infantgut, as well as OWOB outcomes.
Several studies haveinvestigated maternal OWOB- associated changes in microbiota of the infant gut.20 Prepreg- nancy overweighthas been found to affect microbial compo- sition in infant stool, manifested asincreases in Bacteroides species, at the ages of 1 month, 6 months,21and 2 years.13 Mi- crobial compositionalchanges associated with maternal OWOB are more evident in newborns aftervaginal rather than cesar- ean delivery, and, for the latter, reductions inBacteroides are seen.22 Nogut dysbiosis in relation to maternal OWOB has been found in later infancy atages 9 and 18 months.23 Althoughce- sarean delivery alters the structure of gut microbiota during early life,24,25 it remains to be determinedwhether birth mode plays a role in maternal OWOB-related changes to the micro-biota of the infant gut and subsequent risk for OWOB. To ad- dress this gap inknowledge, we determined the joint associa- tions of maternal prepregnancy OWOBand birth mode with microbial composition of the infant gut and microbiotainter- actions at ages 3 to 4 months, and with OWOB outcomes at ages 1 and 3years. Second, we assessed whether microbiota of the infant gut mediated theassociation between maternal OWOB and child OWOB, and whether the mediation wasdependent on birth mode.
实验综述
① 纳入2009-2012年出生的935名加拿大足月产健康婴儿进行观察性研究；
② 与体重正常孕妇顺产的婴儿相比，超重/肥胖孕妇顺产的婴儿及超重孕妇剖腹产的婴儿，在1、3岁时的超重风险分别是前者的3倍和5倍；
③ 超重孕妇产下的婴儿肠道菌群中厚壁菌门（尤其是毛螺菌科）丰度显著增加；
④ 对于不同分娩方式出生的婴儿，毛螺菌科中的不同菌属介导了产妇超重与婴儿超重的关联；
⑤ 剖腹产和毛螺菌科丰度增加介导婴儿1、3岁时母亲到后代的超重/肥胖跨代传递。