This study investigates the therapeutic potential of human placental mesenchymal stem cells (P-MSCs) and their extracellular vesicles (EVs) in a murine model of acute respiratory distress syndrome (ARDS), a condition with growing relevance due to its association with severe COVID-19. We induced ARDS-like lung injury in mice using intranasal LPS instillation and evaluated histological changes, neutrophil accumulation via immunohistochemistry, bronchoalveolar lavage fluid cell count, total protein, and cytokine concentration, as well as lung gene expression changes at three time points: 24, 72, and 168 h. We found that both P-MSCs and EV treatments reduced the histological evidence of lung injury, decreased neutrophil infiltration, and improved alveolar barrier integrity. Analyses of cytokines and gene expression revealed that both treatments accelerated inflammation resolution in lung tissue. Biodistribution studies indicated negligible cell engraftment, suggesting that intraperitoneal P-MSC therapy functions mostly through soluble factors. Overall, both P-MSC and EV therapy ameliorated LPS-induced lung injury. Notably, at the tested dose, EV therapy was more effective than P-MSCs in reducing most aspects of lung injury.

Elsholtzia ciliata essential oil (E. ciliata) has been reported to have an impact on the cardiovascular system. However, its toxicity remains unknown. Therefore, the objective of this investigation was to evaluate the toxicological aspects of the E. ciliata extract. Male Balb/c mice were subjected to either acute (a single dose administered for 24 h) or sub-chronic (daily dose for 60 days) intraperitoneal injections of the E. ciliata extract. The mice were assessed for blood hematological/biochemical profiles, mitochondrial functions, and histopathological changes. Additionally, in vitro cytotoxicity assessments of the E. ciliata extract were performed on immobilized primate kidney cells (MARC-145, Vero) and rat liver cells (WBF344) to evaluate cell viability. The control groups received an equivalent volume of olive oil or saline. Our results demonstrated no significant detrimental effects on hematological and biochemical parameters, mitochondrial functions, cellular cytotoxicity, or pathological alterations in vital organs following the intraperitoneal administration of the E. ciliata extract over the 60-day sub-chronic toxicity study. In general, E. ciliata displayed no indications of toxicity, suggesting that the E. ciliata extract is a safe natural product with a well-defined therapeutic and protective index (found to be 90 and 54, respectively) in Balb/c mice.

The angiotensin-converting enzyme 2 (ACE2)-angiotensin-(1-7)-Mas receptor axis plays a significant role in regulating myocardial remodeling and the development of heart failure (HF), with ACE2 being the primary focus. However, contemporary understanding of the membrane-bound form of the human ACE2 protein remains insufficient. The purpose of this study was to determine the expression of ACE2 protein in different cells of the left ventricular myocardium in non-diseased hearts and at various stages of ischemic HF. A total of 103 myocardial tissue samples from the left ventricle underwent quantitative and semi-quantitative immunohistochemical analysis. Upon assessing ACE2 immunostaining in all myocardial cells through unselective digital image analysis, there was no change in the stage A HF group. Nevertheless, the expression of ACE2 membrane protein in cardiomyocytes showed a tendency to increase, while non-cardiomyocyte ACE2 expression decreased significantly (p < 0.001). In the stage B HF group, the intensity of ACE2 immunostaining continued to increase with rising cardiomyocyte ACE2 expression (p < 0.001). Non-cardiomyocyte expression, in contrast, remained similar to that observed in the stage A HF group. In the stages C/D HF group, ACE2 expression reached its highest level in cardiomyocytes (p < 0.001), while ACE2 expression in non-cardiomyocytes was the lowest (p < 0.001). These changes in ACE2 protein levels are associated with left ventricular remodeling in ischemic HF.

The formation of extracellular traps (ETs) through ETosis has emerged as a key mechanism in immunothrombosis. However, the temporal dynamics and clinical significance of ETosis in coronary thrombi of ST-elevation myocardial infarction (STEMI) patients remain incompletely understood. We investigated whether ETosis burden increases with thrombus age and is associated with DNASE1 and TREX1 genetic variants as well as impaired myocardial reperfusion. Thrombus aspirates from 81 STEMI patients undergoing primary percutaneous coronary intervention were histologically classified as fresh (n = 41) or lytic (n = 40). ETosis was quantified by citrullinated histone H3 (CitH3) immunohistochemistry and digital image analysis, complemented by multiplex staining for myeloperoxidase (MPO), CD68, caspase 3, and CD61. Plasma ET-related markers and genotyping of DNASE1 (rs1053874) and TREX1 (rs11797) were also performed. CitH3-positive cells were present in all thrombi but were more abundant in lytic (older) thrombi compared with fresh thrombi (1348 vs. 591 cells/mm², p < 0.001). Increased ETosis was associated with neutrophil and macrophage infiltration, apoptosis, prolonged ischemia time, elevated systemic inflammation (neutrophil–lymphocyte ratio and C-reactive protein), and impaired myocardial reperfusion (lower TIMI flow grades). Moreover, the DNASE1 GG genotype was associated with higher densities of MPO- and CD68-positive cells, whereas the TREX1 CC genotype was associated with increased densities of CitH3-, MPO-, and CD68-positive cells. This study demonstrates that ETosis increases with coronary thrombus maturation and is associated with local inflammation and impaired reperfusion in STEMI. Genetic variants in DNASE1 and TREX1 may modulate inflammatory cell accumulation within thrombi. These findings suggest ETosis as a potential therapeutic target, particularly in patients with delayed presentation.

Background and Objectives: The combination of aortic valve stenosis (AS) and ischemic heart disease (IHD) is quite common and is associated with myocardial fibrosis (MF). The purpose of this study was to evaluate the association between the histologically verified left ventricular (LV) MF and its geometry and function in isolated AS and AS within IHD groups. Materials and Methods: In a single-center, prospective trial, 116 patients underwent aortic valve replacement (AVR) with/without concomitant surgery. The study population was divided into groups of isolated AS with/without IHD. Echocardiography was used, and LV measurements and aortic valve parameters were obtained from all patients. Myocardial tissue was procured from all study patients undergoing elective surgery. Results: There were no statistical differences between isolated AS and AS+IHD groups in LV parameters or systolic and diastolic functions during the study periods. The collagen volume fraction was significantly different between the isolated AS and AS+IHD groups and was 7.3 ± 5.6 and 8.3 ± 6.4, respectively. Correlations between MF and left ventricular end-diastolic diameter (LVEDD) (r = 0.59, p = < 0.001), left ventricular mass (LVM) (r = 0.42, p = 0.011), left ventricular ejection fraction (LVEF) (r = −0.67, p < 0.001) and an efficient orifice area (EOA) (r = 0.371, p = 0.028) were detected in isolated AS during the preoperative period; the same was observed for LVEDD (r = 0.45, p = 0.002), LVM (r = 0.36, p = 0.026), LVEF (r = −0.35, p = 0.026) and aortic annulus (r = 0.43, p = 0.018) in the early postoperative period; and LVEDD (r = 0.35, p ≤ 0.05), LVM (r = 0.43, p = 0.007) and EOA (r = 0.496, p = 0.003) in the follow-up period. In the group of AS and IHD, correlations were found only with LV posterior wall thickness (r = 0.322, p = 0.022) in the follow-up period. Conclusions: Histological MF in AS was correlated with LVM and LVEDD in all study periods. No correlations between MF and LV parameters were found in aortic stenosis in the ischemic heart disease group across all study periods.

Matrix metalloproteinase 3 (MMP3), in conjunction with other MMPs, plays a key role in myocardial remodeling by breaking down the extracellular matrix of the heart and the development of heart failure (HF). However, the existing data on MMP3 protein expression in human myocardium remains insufficient. The objective of the present study was to determine the expression of MMP3 protein in left ventricular myocardial cells at varying stages of ischemic HF. To this end, a quantitative and semi-quantitative immunohistochemical analysis was performed on 113 samples of left ventricular myocardium. A non-selective digital myocardial image analysis revealed that the stage A HF group exhibited higher MMP3 protein expression compared to the control group (p < 0.001). Subsequent increases in immunostaining intensity of MMP3 were observed in the stage B HF group (p < 0.001). In the stage C/D HF group, MMP3 expression reached its highest level (p < 0.001). The intensity of immunostaining exhibited comparable tendencies in both cardiomyocytes and non-cardiomyocytes. Increased levels of MMP3 immunostaining in both types of cells were associated with increased left ventricular mass. Subjects who carried the 5A allele and patients with the 5A homozygous genotype exhibited a higher propensity for increased immunostaining levels in both cardiomyocytes and non-cardiomyocytes when compared to those with the 6A/6A and 5A/6A genotype. These changes in MMP3 protein expression were associated with left ventricular myocardial remodeling in the progression of ischemic HF.