Using Comparative Transcriptomics and Histology to Identify Significant Differentially Expressed Genes Associated with Retained Placenta in Humans and Rhesus Macaques (Macaca mulatta).

Retained placenta is an important reproductive complication that affects humans and nonhuman primates (NHPs). Accurate prediction of retained placenta in both species is a current challenge because the etiology is unknown, biomarkers are inadequate, and data are heterogeneous. Through a comparative approach, this study identifies 34 significantly differentially expressed genes associated with retained placenta shared between humans and NHPs. Pathway enrichment revealed upregulation in innate and adaptive immunity in addition to pathways related to hemostasis. Retained placentas in NHPs had higher histologic evidence of inflammation as compared with human samples. These cross-species transcriptional results can serve as an initial step to guide NHP refinement as a model system and inform retained placenta biomarker discovery in both humans and NHPs.