This study investigates T cell subsets in pericardial fluid samples obtained from heart transplantation donors, heart transplantation recipients, and coronary artery bypass graft patients. Using flow cytometry, we characterized regulatory T cells (Tregs), tissue-resident memory T cells (Trm), and exhausted T cells based on specific markers. Our results showed significant alterations in the CD4⁺ and CD8⁺ T cell subsets, migration (CXCR3, CCR5), and exhaustion markers (PD-1, TIM3) across the groups. Notably, Tregs and Trm cells were enriched in recipients, while markers of T cell exhaustion showed a complex regulation. These findings provide novel insights into the local immune regulation in cardiac disease and transplantation.

Background: Due to the difficulty of identifying the window of receptivity, a molecular understanding of endometrial changes after fertilization is essential for improving the effectiveness of in vitro fertilization (IVF). This multi-level study examines the compo-sition of cytokines and extracellular vesicles (EVs) in uterine lavage samples obtainable via a noninvasive procedure in mice. The goal is to offer a new perspective on the tim-ing of embryo transfer. Methods: We performed flow cytometric analyses of inflamma-tory cytokines and EVs in uterine lavage samples collected from CD1 mice at the pre-receptive stage (2.5 days post coitum [dpc]) and the receptive stage (4.5 dpc). We also assessed endometrial progesterone receptor expression via immunohistochemistry and evaluated the expression of adhesion molecules related to implantation by RT-PCR. Re-sults: Significant differences were found in the concentrations of inflammatory cyto-kines (IL-6, IFN-γ, and MCP-1), the EV pattern in uterine lavage fluid, and the expres-sion of some genes related to implantation (CD44, CD81, and CD29). These results re-veal uterine lavage fluid markers associated with endometrial receptivity. Using these noninvasive markers can improve the effectiveness of IVF by enabling more precise timing of embryo transfer.

Extracellular vesicles (EVs) are lipid bilayer-delimited particles that are naturally released from all types of cells into the extracellular environment. During their release to the extracellular space, EVs adsorb biomolecules, collectively designated as EV corona. In this study, we developed a novel method for immobilizing EVs and assessing their capacity to bind biomolecules, using human serum albumin (HSA) as a model molecule for corona acquisition and optical waveguide lightmode spectroscopy as the analytical technique. Ten ng/mL poly-L-lysine (15–30 kDa), prepared in 42 mM TRIS buffer at pH 7.4, was used to achieve non-specific immobilization of EVs at a concentration of 4.5 × 10¹⁰ particles/mL, and also to provide surface passivation against proteins. The experiments were performed at 25 °C with a 100 µL/min flow rate. The optimal HSA detection range was between 1 and 100 ng/mL with EC₅₀ = 2.39 ng/mL. A mathematical model was also established to determine the estimated number of HSA molecules that can be bound on the surface of EVs. In saturation experiments it was demonstrated that the magnitude of HSA bound on the surface of EVs corresponded to the theoretical estimate. After its development, the method was further tested using human plasma and a chosen protein (DJ-1) as well as non-protein corona components, specifically double-stranded DNA and a microRNA (miR494).