Life-threatening inflammatory conditions such as acute respiratory distress syndrome or sepsis often go hand in hand with severe vascular leakage. During inflammation, endothelial cell integrity and intact barrier function are crucial to limit leukocyte and plasma extravasation. Prostaglandin D₂ (PGD₂) is a potent inflammatory lipid mediator with vasoactive properties. It has been suggested that PGD^­₂ is involved in the regulation of endothelial barrier function; however, it is unclear whether this is also true for primary human pulmonary microvascular endothelial cells. Furthermore, as PGD₂ is a highly promiscuous ligand, we set out to determine which receptors are important in human pulmonary endothelial cells. In the current study, we found that PGD₂ and the DP1 agonist BW245c potently strengthened pulmonary and dermal microvascular endothelial cell barrier function and protected against thrombin-induced barrier disruption. Yet surprisingly, these effects were mediated only to a negligible extent via DP1 receptor activation. In contrast, we observed that the EP4 receptor was most important and mediated the barrier enhancement by PGD₂ and BW245c. These data demonstrate a novel mechanism by which PGD₂ may modulate inflammation and emphasizes the role of EP4 receptors in human endothelial cell function.

Previous studies found high but very variable levels of tetranor-PGEM and PGD-M (urine metabolites of prostaglandin (PG) E2 and PGD2, respectively) in persons with cystic fibrosis (pwCF), which correlated with the severity of the CF transmembrane receptor (CFTR) genetic alteration. This study aims to assess the potential role of cyclooxygenase (COX)-1 and COX-2 genetic polymorphisms in the variability of PG production, and determine the potential role of PG metabolites as markers of symptoms severity and imaging findings. Thirty healthy subjects and 103 pwCF were included in the study. Clinical and radiological CF severity was evaluated using clinical scoring methods and the extent of bronchiectasis and air trapping were assessed by chest computed tomography (CT). Urine metabolites were measured using liquid chromatography/tandem mass spectrometry. The presence of variants in the COX-1 gen (PTGS1 639 C>A, PTGS1 762+14delA, and COX-2 gen: PTGS2-899G>C (-765G>C) and PTGS2 (8473T>C) were analysed. PGE-M and PGD-M urine concentrations were significantly higher in pwCF than in healthy controls. There were also statistically significant differences between clinically mild and moderate disease and severe disease. Patients with bronchiectasis and/or air trapping had higher PGE-M levels than patients without these complications. The four polymorphisms did not associate with clinical severity, air trapping, bronchiectasis, or urinary PG levels. Taken together, the present study suggests that urinary PG level testing can be used as a biomarker of CF severity. We found no relationship between COX-1 and COX-2 genetic polymorphisms in the variability of PG production.

It has been reported that prostaglandin I2, such as epoprostenol, develops Grave's disease. A 34-year-old woman was diagnosed with idiopathic pulmonary arterial hypertension and started receiving continuous intravenous epoprostenol. Three years after starting epoprostenol, she started complaining of neck swelling and was diagnosed with Grave’s disease. Thyroid function was controlled by thiamazole and levothyroxine. Nevertheless, her thyroid gland enlargement worsened as epoprostenol dose was titrated. After 23 years of treatment with epoprostenol, she suddenly experienced respiratory failure with a giant goiter leading to airway stenosis and passed away. The autopsy confirmed a giant goiter associated with hyperthyroidism and airway stenosis. We experienced a case of idiopathic pulmonary hypertension with a giant goiter and airway stenosis after long-term intravenous epoprostenol therapy.

The effect of prostaglandin E1 (PGE1) encapsulated in nanoparticles (Nano PGE1) on motor dysfunction and muscle atrophy induced by sciatic nerve injury (SNI) was investigated in rats, and was compared with PGE1 encapsulated in lipid microspheres (Lipo PGE1) or PGE1 clathrated in cyclodextrin (PGE1-CD). The hind limb muscle weight ratio decreased until 2 weeks after SNI. All 3 PGE1 formulations significantly improved SNI-induced motor dysfunction. Nano PGE1 significantly promoted recovery from muscle atrophy at 2 and 3 weeks after SNI. Lipo PGE1 was also effective, but multiple doses were required. Compared with the SNI control group, the Nano PGE1 group showed upregulation of vascular endothelial growth factor (VEGF) and agrin expression in the injured sciatic nerve and atrophic muscles. Nano PGE1 accumulated prominently at the site of nerve injury and persisted for longer than Lipo PGE1 or PGE1-CD. Expression of all EP receptors was detected in the normal sciatic nerve, and EP2 expression increased after SNI. Finally, Nano PGE1 promoted ERK1/2 and Akt phosphorylation. These findings suggest that PGE1 released from nanoparticles accumulates at sites of nerve injury and increases VEGF production by augmenting ERK1/2 phosphorylation via EP receptor signaling, thus promoting tissue repair and regeneration.

Oxidative stress and inflammation are basic pathogenic factors involved in tissue injury, pain, as well as acute and chronic diseases. Since long-term uses of steroids and non-steroidal anti-inflammatory drugs (NSAIDs) cause severe adverse effects, novel effective materials with minimal side effects are required. In this study, polyphenol content and antioxidative activity of rosebud extracts from 24 newly-crossbred Korean roses were analyzed. Among them, Pretty Velvet rosebud extract (PVRE) were found to contain high polyphenols and to show in vitro antioxidative and anti-inflammatory activities. In RAW 264.7 cells stimulated with lipopolysaccharide (LPS), PVRE down-regulated mRNA expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and thereby decreased nitric oxide (NO) and prostaglandin E2 (PGE2) production. In an air-pouch inflammation model, treatment with PVRE decreased λ-carrageenan-induced tissue exudation, infiltration of inflammatory cells including neutrophils, monocytes and lymphocytes, and tumor necrosis factor-α and interleukin-1β concentrations, as achieved with dexamethasone (a steroid). Notably, PVRE also inhibited PGE2, similar to dexamethasone and indomethacin (an NSAID). The anti-inflammatory effects of PVRE were confirmed by microscopic findings, attenuating tissue erythema, edema, and inflammatory cell infiltration. These results indicate that PVRE exhibits dual (steroid- and NSAID-like) anti-inflammatory activities by blocking both the iNOS ― NO and COX-2 ― PG pathways, and that PVRE could be a promising anti-inflammatory material for diverse issue injuries.

The aim of the study was to determine the possibility of suppression of the prostaglandin synthesis by new derivatives of N-phenylanthranilic acids; they inhibit the activity of the microsomal prostaglandin E synthase-1 (mPGES-1) enzyme using the method of a flexible molecular docking. For the docking studies the crystallographic structural models with high resolution from Protein Data Bank were used: mPGES-1 in the complex with glutathione (pdb code 4AL0). A flexible molecular docking was carried out using the Molecular Operating Environment (MOE) software package. According to the results of the docking studies four scoring functions were calculated (Affinity dG Scoring, Alpha HB Scoring, London dG Scoring, GBVI/WSA dG Scoring). The values of the scoring functions calculated indicate the thermodynamic probability and energy favorability of forming complexes between molecules of the substances under research and the specified receptor, in which arrangement of ligands in the active site of the receptor and residues of amino acids of side chains are of similar geometry and types of binding of the known inhibitors of mPGES-1 determined on the basis of the crystallographic studies.

People with sickle cell disease (SCD) are at greater risk of severe illness and death from respiratory infections, including COVID-19 than people without SCD (Centers for Disease Control and Prevention, USA). Vaso-occlusive crises (VOC) in SCD and severe SARS-CoV-2 infection are both characterized by thrombo-inflammation mediated by endothelial injury, complement activation, inflammatory lipid storm, platelet activation, platelet-leukocyte adhesion, and activation of the coagulation cascade. Notably, lipid mediators, including thromboxane A2, significantly increase in severe COVID-19 and SCD. In addition, the release of thromboxane A2 from endothelial cells and macrophages stimulates platelets to release microvesicles which are harbingers of multicellular adhesion and thrombo-inflammation. Currently, there are limited therapeutic strategies targeting platelet-neutrophil activation and thrombo-inflammation in either SCD or COVID-19 during acute crisis. However, due to many similarities between the pathobiology of thrombo-inflammation in SCD and COVID-19, therapies targeting one disease may likely be effective in the other. Therefore, the preclinical and clinical research spurred by the COVID-19 pandemic, including clinical trials of anti-thrombotic agents, are potentially applicable to VOC. Here, we first outline the parallels between SCD and COVID-19; second, review the role of lipid mediators in the pathogenesis of these diseases and lastly, examine the therapeutic targets and potential treatments for the two diseases.

Background. Epidemiological and clinical studies demonstrated that excessive salt intake causes severe hypertension and exacerbated organ derangement such as chronic kidney disease (CKD). In this study, we focused on evaluating histological and gene-expression findings in the kidney using stroke-prone spontaneously hypertensive rats (SHRSP) with high-salt intake and thromboxane A2/ prostaglandin H2 receptor (TPR) blocker ONO-8809. Methods. SHRSP aged 6 weeks were divided into three groups eating normal chow containing 0.4% NaCl, 2.0%NaCl, or 2.0%NaCl +ONO-8809 (0.6mg/kg p.o. daily). Histological analyses with immunohistochemistry and a gene-expression assay with a DNA kidney microarray were performed after 8 weeks. Results. The following changes were observed with high-salt intake. Glomerular sclerotic changes were remarkably observed in the juxtaglomerular cortex areas. ED1, MCP-1, nitrotyrosine, and HIF-1α staining areas were increased in the glomeruli and interstitial portion. Tbxa2r which encodes TPR, Prcp, and Car7 were significantly underexpressed in the kidney. The plasma 8-isoprostane level was significantly elevated, and was attenuated with ONO-8809 treatment. Conclusion. TXA2 and oxidative stresses exaggerated renal dysfunction in salt-loading SHRSP, and ONO-8809 as a TPR blocker suppressed these changes. Therefore, ONO-8809 is a candidate drug to prevent CKD for hypertensive patients associated with high-salt intake.