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.