Development of an In Vitro Model of SARS-CoV-Induced Acute Lung Injury for Studying New Therapeutic Approaches.

One of the causes of death of patients infected by SARS-CoV-2 is the induced respiratory failure caused by excessive activation of the immune system, the so-called "cytokine storm", leading to damage to lung tissue. In vitro models reproducing various stages of the disease can be used to explore the pathogenetic mechanisms and therapeutic approaches to treating the consequences of a cytokine storm. We have developed an in vitro test system for simulating damage to the pulmonary epithelium as a result of the development of a hyperinflammatory reaction based on the co-cultivation of pulmonary epithelial cells (A549 cells) and human peripheral blood mononuclear cells (PBMC) primed with lipopolysaccharide (LPS). In this model, after 24 h of co-cultivation, a sharp decrease in the rate of proliferation of A549 cells associated with the intrinsic development of oxidative stress and, ultimately, with the induction of PANoptotic death were observed. There was a significant increase in the concentration of 40 cytokines/chemokines in a conditioned medium, including TNF-α, IFN-α, IL-6, and IL-1a, which corresponded to the cytokine profile in patients with severe manifestation of COVID-19. In order to verify the model, the analysis of the anti-inflammatory effects of well-known substances (dexamethasone, LPS from Rhodobacter sphaeroides (LPS-RS), polymyxin B), as well as multipotent mesenchymal stem cells (MSC) and MSC-derived extracellular vesicles (EVs) was carried out. Dexamethasone and polymyxin B restored the proliferative activity of A549 cells and reduced the concentration of proinflammatory cytokines. MSC demonstrated an ambivalent effect through stimulated production of both pro-inflammatory cytokines and growth factors that regenerate lung tissue. LPS-RS and EVs showed no significant effect. The developed test system can be used to study molecular and cellular pathological processes and to evaluate the effectiveness of various therapeutic approaches for the correction of hyperinflammatory response in COVID-19 patients.

Extracellular DNA levels and cytokine profiles in preterm birth: a cohort study.

PURPOSE: The content of eight different cytokines, cell-free DNA (cfDNA) and cell-free fetal DNA (cffDNA) in women's plasma during preterm birth (PB) was studied. The purpose of this study was to identify the relationships between the investigated factors and determine their prognostic significance. METHODS: Venous blood samples were collected from 45 women with PB and 35 women with full-term labor at 22-31 and 32-36 weeks of gestation, as well as from 17 women during labor at 39-40 weeks of gestation. The concentration of IL-2, IL-4, IL-6, IL-8, IL-10, GM-CSF, IFN-γ and TNF-α cytokines in peripheral blood plasma was measured by multiplex method. The level of cfDNA and cffDNA was evaluated using PCR analysis. RESULTS: It was found that, the level of IL-6, IL-8 and cfDNA in the blood was significantly increased in women with PB at 22-31 weeks of gestation (p = 0.044, p = 0.001, p < 0.001) and 32-36 weeks of gestation (p = 0.025, p = 0.001, p = 0.002) compared to women with physiological pregnancy at the same terms. The level of cffDNA (p = 0.014) was significantly increased in women with PB at 32-36 weeks of gestation. The IL-8 content had a significant correlation with the cfDNA level in women with PB at all stages of labor and with the cffDNA level in the group who gave birth at 32-36 weeks of gestation. There was no correlation between IL-8, cfDNA and cffDNA, but there was consistency with other cytokines at all studied terms and during delivery in the term-delivery group. CONCLUSION: The results of the study suggest that cfDNA is a potential marker of PB and show that the aberrant relationship between cfDNA and IL-8 may be important in the genesis of PB.

Mesenchymal Stromal Cells Isolated from Ectopic but Not Eutopic Endometrium Display Pronounced Immunomodulatory Activity In Vitro.

A comparative analysis of the cell surface markers and immunological properties of cell cultures originating from normal endometrium and endometrioid heterotopias of women with extragenital endometriosis was carried out. Both types of cell cultures expressed surface molecules typical of mesenchymal stromal cells and did not express hematopoietic and epithelial markers. Despite similar phenotype, the mesenchymal stromal cells derived from the two sources had different immunomodulation capacities: the cells of endometrioid heterotopias but not eutopic endometrium could suppress dendritic cell differentiation from monocytes as well as lymphocyte proliferation in allogeneic co-cultures. A comparative multiplex analysis of the secretomes revealed a significant increase in the secretion of pro-inflammatory mediators, including IL6, IFN-γ, and several chemokines associated with inflammation by the stromal cells of ectopic lesions. The results demonstrate that the stromal cells of endometrioid heterotopias display enhanced pro-inflammatory and immunosuppressive activities, which most likely impact the pathogenesis and progression of the disease.

Epitope-Specific Response of Human Milk Immunoglobulins in COVID-19 Recovered Women.

The breastfeeding of infants by mothers who are infected with SARS-CoV-2 has become a dramatic healthcare problem. The WHO recommends that infected women should not abandon breastfeeding; however, there is still the risk of contact transmission. Convalescent donor milk may provide a defense against the aforementioned issue and can eliminate the consequences of artificial feeding. Therefore, it is vital to characterize the epitope-specific immunological landscape of human milk from women who recovered from COVID-19. We carried out a comprehensive ELISA-based analysis of blood serum and human milk from maternity patients who had recovered from COVID-19 at different trimesters of pregnancy. It was found that patients predominantly contained SARS-CoV-2 N-protein-specific immunoglobulins and had manifested the antibodies for all the antigens tested in a protein-specific and time-dependent manner. Women who recovered from COVID-19 at trimester I-II showed a noticeable decrease in the number of milk samples with sIgA specific to the N-protein, linear NTD, and RBD-SD1 epitopes, and showed an increase in samples with RBD conformation-dependent sIgA. S-antigens were found to solely induce a sIgA1 response, whereas N-protein sIgA1 and sIgA2 subclasses were involved in 100% and 33% of cases. Overall, the antibody immunological landscape of convalescent donor milk suggests that it may be a potential defense agent against COVID-19 for infants, conferring them with a passive immunity.

Phagocyte activity in the peripheral blood of pregnant women with systemic lupus erythematosus and in the cord blood of their newborns.

AIM: To detect faults in phagocytosis in peripheral blood cells of pregnant women with systemic lupus erythematosus (SLE) and in cord blood of their newborns. METHODS: Pregnant women fulfilled ≥ 4 American College of Rheumatology criteria for SLE and their newborns were recruited. Pregnant women without SLE and their newborns constituted controls. Phagocytosis and respiratory burst were measured using PHAGOTEST and BURSTTEST kits (Biotechnology GmbH, Germany) on FACSCalibur™ flow cytometer. Expression of CD11b was estimated with antibodies (BD Biosciences, San Jose, CA, USA). Mann-Whitney rank-sum test was used to compare SLE group and controls. RESULTS: Phagocytosis and respiratory burst were estimated in blood of 31 SLE women (29.5 ± 3.3 years) and in cord blood of 26 newborns. Controls were 21 health women (29.8 ± 2.8 years) and their 21 babies. Median reactive oxygen species (ROS) production was reduced in the SLE group versus controls (arbitrary units): women, 2315 versus 3316 (P = 0.034); babies, 1051 versus 1791 (P = 0.041), respectively. Proportion of ROS-producing granulocytes decreased in the SLE group: women, 72.5% versus 94.0% (P = 0.025); babies, 46.8% versus 90.7% (P = 0.008). Proportion of phagocytes which engulfed Escherichia coli and bacteria number per phagocyte also decreased in SLE women. Monocyte activity was suppressed in newborns from the SLE group (RLU): 224 versus 507 (P = 0.022). CD11b expression was reduced in SLE women (RLU): granulocytes, 588 versus 1448.5 (P < 0.001); monocytes, 1017 versus 1619 (P = 0.002). CONCLUSION: Pregnant SLE women have low ingesting capacity of phagocytes. Suppression of phagocytosis in their newborns is mainly due to reduced number of cells producing ROS.