Acute respiratory distress syndrome: potential of therapeutic interventions effective in treating progression from COVID-19 to treat progression from other illnesses-a systematic review

Restoring natural killer cell activity in lung injury with 1,25-hydroxy vitamin D3: a promising therapeutic approach

Background and aim

NK cells and NK-cell-derived cytokines were shown to regulate neutrophil activation in acute lung injury (ALI). However, the extent to which ALI regulates lung tissue-resident NK (trNK) activity and their molecular phenotypic alterations are not well defined. We aimed to assess the impact of 1,25-hydroxy-vitamin-D3 [1,125(OH)2D] on ALI clinical outcome in a mouse model and effects on lung trNK cell activations.

Methods

Oleic acid (OA)-induced ALI in C57BL/6J mice and 1,25(OH)2D treatment 2×/2 weeks were performed. Lung tissue was harvested to assess alveolar I/II cell apoptosis and lung injury marker of Surfactant-Protein-D (SP-D). Pulmonary edema markers of epithelial sodium channel, cystic fibrosis transmembrane conductance regulator, and aquaporin 5 were assessed by RT-PCR. Lung trNK cells were assessed for activation markers of CD107a and NKp46, vitamin D receptor (VDR), and programmed cell death protein-1 (PD-1) via flow cytometry. The bronchoalveolar lavage fluid (BALF) obtained was investigated for soluble receptor for advanced glycation end products (sRAGE), inflammatory cytokines, soluble 1,25(OH)2D, and PDL-1. Naïve mice treated with DMSO (vehicle) were used as a control.

Results

Flow cytometry analysis displayed a high apoptotic rate in alveolar I/II cells of threefold in ALI mice as compared to naïve mice. These findings were accompanied by elevated markers of pulmonary edema as well as lung injury markers of SP-D. Isolated lung trNK cells of the ALI mice exhibited reduced CD107a and NKp46 markers and cytotoxicity potentials and were correlated through significantly 2.1-fold higher levels of PD-1 and diminished VDR expressions as compared to naïve mice. BALF samples of ALI mice displayed high soluble PDL-1 and reduced soluble 1,25(OH)2D levels compared to naïve mice. 1,25(OH)2D treatment alongside OA led to a significant fourfold increase in the CD107a and NKp46 expressions to levels higher than the mice treated with the vehicle. Furthermore, 1,25(OH)2D ameliorates free radical scavengers of GSH, GPX, CAT, and GPx-1; decreased pro-inflammatory cytokines and soluble PDL-1; and increased soluble 1,25(OH)2D with amelioration in pulmonary edema markers and alveolar I/II apoptosis.

Conclusion

Our results indicate 1,25(OH)2D's potential therapeutic effect in preventing clinical outcomes associated with ALI via regulating NK cells through inhibiting inflammatory cytokines and alleviating levels of PDL-1 and 1,25(OH)2D released by lung tissue.

Central line-associated bloodstream infections in patients with COVID-19

OBJECTIVE

to investigate the association between central line-associated bloodstream infections and clinical and care variables of intensive care unit patients with COVID-19 hospitalized at a reference public health institution.

METHOD

a case-control study.

RESULTS

the study sample consisted of 70 patients diagnosed with central line-associated bloodstream infections (case group) and 70 non-infected patients (control group). Most patients were male, with mean age of 57.93±13.93 years old and provided with a double lumen catheter. Median time of central line-associated bloodstream infections onset was 11 (8-18) days. Longer time on mechanical ventilation ( P =0.014; OR: 1.79; 95% CI: 0.91-3.51) and prone position ( P =0.017; OR: 2.41; 95% CI: 1.22-4.81) were associated with central line-associated bloodstream infections onset.

CONCLUSION

longer time on invasive mechanical ventilation and prone position contributed to central line-associated bloodstream infections onset in COVID-19 patients.

Hypoxia-adenosine axis as therapeutic targets for acute respiratory distress syndrome

The human respiratory and circulatory systems collaborate intricately to ensure oxygen delivery to all cells, which is vital for ATP production and maintaining physiological functions and structures. During limited oxygen availability, hypoxia-inducible factors (HIFs) are stabilized and play a fundamental role in maintaining cellular processes for hypoxia adaptation. First discovered during investigations of erythropoietin production regulation, HIFs influence physiological and pathological processes, including development, inflammation, wound healing, and cancer. HIFs promote extracellular adenosine signaling by enhancing adenosine generation and receptor signaling, representing an endogenous feedback mechanism that curbs excessive inflammation, supports injury resolution, and enhances hypoxia tolerance. This is especially important for conditions that involve tissue hypoxia, such as acute respiratory distress syndrome (ARDS), which globally poses significant health challenges without specific treatment options. Consequently, pharmacological strategies to amplify HIF-mediated adenosine production and receptor signaling are of great importance.