PTB_cor_gene_to_gene and cor_gene_to_metabolite.xlsx

<b>Collection of Human Placentas</b>Human placental samples were obtained from two distinct cohorts, analyzed in two separate comparisons: first trimester vs. term placentas to study placental development and PTB vs. term placentas to investigate metabolic alterations under pathological conditions. For the developmental study, first-trimester (n=10) and term placentas (n=10) were analyzed. A separate set of term placentas (n=10) was used for the PTB vs. term comparison, ensuring that developmental analysis was independent of pathological conditions. PTB placentas (n=10) were selected from spontaneous preterm births without infection-related etiology and matched to term samples by gestational age where possible. The study was conducted at the Department of Obstetrics and Gynecology, University Hospital in Hradec Kralove, Czech Republic, between May 2019 and May 2022.Only placentas from singleton pregnancies with no maternal metabolic disorders, infections, or known chromosomal abnormalities were included. Ethical approval was granted by the University Hospital Research Ethics Committee (201006 S15P). Informed written consent was obtained from all participants. The study adheres to the Declaration of Helsinki and institutional guidelines.<b>Analysis of purine and pyrimidine metabolites in the placenta</b>Sample preparation and the analysis of purine and pyrimidine metabolite content were carried out in the previous study by Cifkova et al. Placenta samples were analyzed using the UHPLC/MS with an Acquity I-class UPLC instrument and a Vion IMS QTOF mass spectrometer (Waters, Milford, MA, USA). An Acquity UPLC HSS T3 column (150 × 2.1 mm, 1.8 µm, Waters) and gradient of 0.1% formic acid in water and 0.1% formic acid in methanol was used for separation.<b>Pearson Correlation Analysis for Gene-to-Metabolite and Gene-to-Gene Relationships</b>The Pearson correlation coefficients for gene-to-metabolite and gene-to-gene relationships were computed using gene expression data obtained from 10 PTB placentas and 10 term placentas quantified in this study and metabolite levels previously determined by Cifkova et al. Thus, the total sample size for these correlations amounted to 20. The correlation factors and p-values were calculated using <i>rstatix</i> functions and the results were plotted by <i>ggplot2</i> package. In our study, a Pearson correlation value ranging from (0.5 to 0.7 or -0.5 to -0.7) indicates a moderate correlation whether positive or negative, while a positive or negative correlation from (-0.7 to -0.9, 0.7 to 0.9) indicates a strong correlation.

<b>人类胎盘样本集</b>本研究从两个独立队列获取人类胎盘样本，开展两组独立对照分析：第一孕期胎盘与足月胎盘对照，用于探究胎盘发育规律；早产（Preterm Birth, PTB）胎盘与足月胎盘对照，用于研究病理状态下的代谢改变。针对发育探究队列，我们分析了10例第一孕期胎盘与10例足月胎盘；而早产对照队列则单独使用10例足月胎盘，以此确保发育相关分析不受病理因素干扰。早产队列的10例胎盘取自无感染相关病因的自发性早产病例，且尽可能按胎龄与足月胎盘样本进行匹配。本研究于2019年5月至2022年5月间，在捷克赫拉德茨-克拉洛韦大学医院妇产科开展。纳入研究的胎盘仅来自单胎妊娠，且母体无代谢紊乱、感染或已知染色体异常情况。本研究已获得赫拉德茨-克拉洛韦大学医院研究伦理委员会批准（审批号：201006 S15P），所有参与者均签署了书面知情同意书。研究严格遵循《赫尔辛基宣言》及机构相关指南。<b>胎盘组织中嘌呤与嘧啶代谢物分析</b>嘌呤与嘧啶代谢物的样本制备及含量检测工作，已在Cifkova等人此前的研究中完成。本研究采用超高效液相色谱-质谱联用（UHPLC/MS）系统，搭配Acquity I-class超高效液相色谱仪与Vion IMS QTOF质谱仪（Waters, Milford, MA, USA）对胎盘样本进行检测。色谱分离采用Acquity UPLC HSS T3色谱柱（150 × 2.1 mm, 1.8 µm, Waters），流动相为含0.1%甲酸的水溶液与含0.1%甲酸的甲醇溶液，通过梯度洗脱完成样本分离。<b>基因-代谢物与基因-基因关联的皮尔逊相关分析</b>本研究针对基因-代谢物及基因-基因的关联计算皮尔逊相关系数，所用数据包括本研究中定量得到的10例早产胎盘与10例足月胎盘的基因表达数据，以及Cifkova等人此前测定的代谢物水平。因此本次相关分析的总样本量为20例。相关系数与p值通过<i>rstatix</i>包的函数进行计算，分析结果则通过<i>ggplot2</i>包进行可视化绘图。本研究中，皮尔逊相关系数绝对值介于0.5~0.7或-0.7~-0.5时，代表存在中等强度的正负相关；相关系数绝对值介于0.7~0.9或-0.9~-0.7时，则代表存在强正负相关。