miR-21 differentially regulates IL-1β and IL-10 expression in human decidual cells infected with streptococcus B

Intrauterine infections caused by bacteria like group B streptococcus (GBS) and the subsequent activation of the maternal inflammatory response have been long suspected to be the underlying cause of preterm labor. The inflammatory network triggered by maternal decidua has been widely described and includes the secretion of pro- and anti-inflammatory cytokines as IL-1β and IL-10; however, the mechanisms that regulate their secretion have not been completely elucidated. MicroRNAs (miRNAs) are critical modulators of the inflammatory response by regulating cytokine expression in several cell types. Here, we explored the role of miR-21 in the expression of IL-1β and IL-10 in human decidual stromal cells (DSCs) exposed in vitro to GBS. We observed that IL1B and IL10 expression at the mRNA level was increased in DSCs after GBS infection. IL-10 but not IL-1β secretion was detected in the culture supernatants. We found a higher miR-21 expression (22-fold) in infected DSCs as compared with non-infected cells. miR-21 functional analysis revealed that DSCs transfected with an antagomiR vs. miR-21 significantly increased the secretion of IL-1β but decreased that of IL-10 in DSCs cells infected with GBS. Our results suggest that miR-21 participates in balancing the inflammatory response in infected decidua through at least IL-1β and IL-10 regulation. This is the first study attributing a functional role of miR-21 in the regulation of key molecules involved in the inflammatory response in infected DSCs, providing new insights into the epigenetic control of human decidual inflammation.

The histologic evolution of revealed, acute abruptions

There is considerable interest in using pathology to confirm acute abruptions. It has been suggested that pathologic findings can help to determine the timing of abruptions. Because of the dearth of evidence in the literature supporting this claim and its medicolegal implications, we undertook this study to explore further the possibility of timing abruptions by histopathology. We sought to correlate bleeding interval (duration from maternal presentation with vaginal bleeding [revealed abruption] to placental delivery) with placental histopathologic findings. We performed a retrospective review of clinical data and placental pathology from all cases of clinically diagnosed, acute, revealed abruptions at a single, large institution in New England between 2000 and 2015. Cases were identified based on clinical diagnoses, bleeding intervals were calculated from clinical notes, and histologic evaluations were performed by 2 pathologists blinded to the bleeding intervals. A total of 177 cases were analyzed. Of these, 103 (58%) had histologic findings corroborating the clinical diagnosis of abruption. The most frequent finding was maternal surface indentation (51 cases) followed by intravillous hemorrhage (50 cases). The former was also the earliest finding, with a minimum bleeding interval of 4 minutes. In multivariate modeling, plasma cell deciduitis was significantly associated with a longer bleeding interval (median 63 hours). If there were 2 pathologic findings, there was a trend toward a longer bleeding interval. There was modest sensitivity for the pathologic diagnosis of acute revealed abruption. Although there was not a clear, stepwise progression of histologic lesions; the presence of 2 or more findings tended to be seen with longer bleeding intervals. Our results suggest that histologic findings cannot be used to time acute revealed abruptions reliably, and any interpretation of such should be made with caution.