Comparison of Perinatal Outcome of Delta and Omicron Variant of COVID-19 Infection-A Retrospective Observational Study.

Background and Objectives: The aim of the present work was to compare the characteristics of delta and omicron variants of COVID-19 infection in pregnant women, the association of infection with comorbidity, clinical manifestation of the disease, type of delivery, and pregnancy outcome. Material and Methods: The study was designed as an observational, retrospective study of a single center. The analysis included the cohort of women who had SARS-CoV-2 infection during pregnancy and/or childbirth in the period from 1 March 2020 to 30 June 2023. Results: Out of a total of 675 pregnant women with SARS-CoV-2 infection, 130 gave birth with the delta and 253 with the omicron variant. In our retrospective analysis, pregnant women with both SARS-CoV-2 variants had a mild clinical history in most cases. In the omicron period, a significantly lower incidence of pregnancy loss (p < 0.01) and premature birth (p = 0.62) admission of mothers and newborns to the intensive care unit (p < 0.05) was recorded. Conclusions: In our retrospective analysis, pregnant women with COVID-19 infection generally exhibited a milder clinical manifestation with both variants (delta and omicron) of the viral infection. During the delta-dominant period, ten percent of affected pregnant women experienced a severe clinical history. However, during the omicron-dominant period infection, a significantly lower incidence of complications, pregnancy loss, preterm delivery, and admission of mothers and neonates to the intensive care unit was recorded. This can be partly explained by the greater presence of pregnant women with natural or induced vaccine immunity.

Glutathione Transferase P1: Potential Therapeutic Target in Ovarian Cancer.

Chemotherapy resistance of ovarian cancer, regarded as the most lethal malignant gynecological disease, can be explained by several mechanisms, including increased activity of efflux transporters leading to decreased intracellular drug accumulation, increased efflux of the therapeutic agents from the cell by multidrug-resistance-associated protein (MRP1), enhanced DNA repair, altered apoptotic pathways, silencing of a number of genes, as well as drug inactivation, especially by glutathione transferase P1 (GSTP1). Indeed, GSTP1 has been recognized as the major enzyme responsible for the conversion of drugs most commonly used to treat metastatic ovarian cancer into less effective forms. Furthermore, GSTP1 may even be responsible for chemoresistance of non-GST substrate drugs by mechanisms such as interaction with efflux transporters or different signaling molecules involved in regulation of apoptosis. Recently, microRNAs (miRNAs) have been identified as important gene regulators in ovarian cancer, which are able to target GST-mediated drug metabolism in order to regulate drug resistance. So far, miR-186 and miR-133b have been associated with reduced ovarian cancer drug resistance by silencing the expression of the drug-resistance-related proteins, GSTP1 and MDR1. Unfortunately, sometimes miRNAs might even enhance the drug resistance in ovarian cancer, as shown for miR-130b. Therefore, chemoresistance in ovarian cancer treatment represents a very complex process, but strategies that influence GSTP1 expression in ovarian cancer as a therapeutic target, as well as miRNAs affecting GSTP1 expression, seem to represent promising predictors of chemotherapeutic response in ovarian cancer, while at the same time represent potential targets to overcome chemoresistance in the future.