Pregestational overweight and obesity are associated with differences in gut microbiota composition and systemic inflammation in the third trimester

The obesity epidemic is a global challenge, and the velocity of propagation is high in the population at reproductive age. Overweight and obesity during pregnancy have been associated with high birth weight and an increased risk of childhood obesity, reinforcing the risk of other non-communicable diseases. Obesity involves chronic low-grade systemic inflammation. New biomarkers for early detection of obesity risk are urgently required. The aim of this study was to identify the connection between pregestational BMI (pre-BMI) status and inflammatory biomarkers during the third trimester of pregnancy and their association with intestinal microbiota composition. Fifty-four pregnant women were classified according to pre-pregnancy BMI as normoweight, overweight, or obese. Weight gain, inflammatory biomarkers (hs_CRP, haptoglobin, and suPAR), and microbiota composition were assessed during the third trimester. A significant lower weight gain for obese mothers and a positive correlation between pre-BMI and inflammatory biomarkers were detected (Spearman’s correlation). Haptoglobin levels were significantly higher in overweight and obese mothers. Higher Firmicutes levels and a higher ratio Firmicutes/Bacteroidetes were observed in the overweight and obese subjects. High hs_CRP and haptoglobin levels were also correlated with decreased microbiota diversity (Shannon index), whereas haptoglobin and hs_CRP values were correlated with several microbiota components, such as Ruminococcus gnavus and Faecalibacterium, and with specific phyla in the normoweight and overweight mothers; no significant associations with microbiota were found for suPAR. In conclusion, haptoglobin and hs_CRP reflected pregestational BMI status and related microbiota components, but haptoglobin was a better biomarker for microbiota associated with overweight. suPAR was associated with low grade inflammation dependent on pre-pregnancy BMI, but it was not related to deviated microbiota profiles.

肥胖症流行已成为全球性公共卫生难题，育龄群体的传播速度尤为迅猛。孕期超重与肥胖与新生儿出生体重过高、儿童肥胖风险升高相关，进而增加其他非传染性疾病的患病风险。肥胖症伴随慢性低度全身性炎症反应，目前亟需可用于肥胖风险早期筛查的新型生物标志物。本研究旨在明确孕前体重指数（pregestational BMI, pre-BMI）状态与妊娠晚期炎症性生物标志物之间的关联，以及二者与肠道菌群组成的相关性。本研究纳入54名孕妇，依据孕前BMI将其分为体重正常、超重及肥胖三组。研究人员于妊娠晚期对受试者的体重增长情况、炎症性生物标志物（高敏C反应蛋白hs_CRP、结合珠蛋白haptoglobin及可溶性尿激酶型纤溶酶原激活物受体suPAR）水平以及肠道菌群组成进行了检测分析。采用斯皮尔曼（Spearman）相关性分析发现，肥胖孕妇的体重增长显著低于其他组别，且孕前BMI与炎症性生物标志物水平呈正相关。超重及肥胖孕妇的结合珠蛋白水平显著升高。超重及肥胖受试者的厚壁菌门（Firmicutes）丰度更高，厚壁菌门与拟杆菌门（Bacteroidetes）的比值也更大。高hs_CRP及结合珠蛋白水平还与菌群多样性（香农指数，Shannon index）降低显著相关；此外，在体重正常及超重孕妇中，结合珠蛋白与hs_CRP水平与多种菌群组分（如格氏瘤胃球菌Ruminococcus gnavus、普拉梭菌属Faecalibacterium）以及特定菌门存在关联。而suPAR水平与肠道菌群未发现显著相关性。综上，结合珠蛋白与hs_CRP可反映孕前BMI状态及其相关的菌群组分，其中结合珠蛋白是与超重相关菌群关联更优的生物标志物。suPAR与依赖于孕前BMI的低度炎症相关，但与异常菌群谱无关联。