The anti-inflammatory effects of mesenchymal stem cells attenuate diffuse pulmonary hemorrhage.

There are few effective treatment options for diffuse pulmonary hemorrhage (DPH). We aimed to elucidate the therapeutic role and underlying mechanisms of mesenchymal stem cells (MSCs) and MSC-derived extracellular vesicles (MSC-EVs) in DPH. Therapeutic effects of MSCs/MSC-EVs in pristane-induced DPH mice were evaluated via pulmonary function testing and histopathology. Transcriptome sequencing analyzed differentially expressed genes in control, DPH, and MSC groups. The proportion of macrophage polarization was evaluated in vivo and in vitro via fluorescence-activated cell sorting in control, DPH, MSC, MSC-EV inhalation, and MSC-EV intravenous groups. Intraperitoneal injection of pristane induced diffuse alveolar hemorrhage, early fibrosis, and inflammation in C57BL/6 mice. Monocytes were depleted in the peripheral blood in DPH mice and MSCs were recruited to the lungs, resulting in significantly attenuated diffuse alveolar hemorrhage and suppressed immunological response. This was more effective in the hyperacute hemorrhage phase than the early inflammatory phase. An MSC treatment-mediated anti-inflammatory effect was observed in DPH mice. Furthermore, MSC-EVs inhalation or tail-vein injection could effectively reduce DPH injury. MSCs could suppress macrophage M1 polarization in DPH in vivo and in vitro. MSCs displayed significant therapeutic effects in pristane-induced DPH, which may be a promising cell-free therapeutic approach.

Integration of 16S rRNA gene sequencing and LC/MS-based metabolomic analysis of early biomarkers of acute ischaemic stroke in Tibetan miniature pigs.

Acute ischaemic stroke (AIS) is a complex, systemic, pathological, and physiological process. Systemic inflammatory responses and disorders of the gut microbiome contribute to increased mortality and disability following AIS. We conducted 16S high-throughput sequencing and ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry-based non-targeted metabolomic analyses of the plasma from a Tibetan miniature pig middle cerebral artery occlusion (MCAO) model. A significant decrease in the abundance of Firmicutes and a significant increase in the abundance of Actinobacteria were observed after the onset of AIS. Among the plasma metabolites, the levels of phospholipids and amino acids were considerably altered. Loading values and differential metabolite-bacterial group association analyses of the metabolome and microbiome indicated a correlation between the microbiome and metabolome of Tibetan miniature pigs after MCAO. Furthermore, significant changes were observed in the ABC transporter pathway and purine metabolism in the gut microbiome-plasma metabolome during the early stage of AIS. Kyoto Encyclopaedia of Genes and Genomes enrichment analysis showed that arginine, proline, and cyanoamino acid metabolism was upregulated while ABC transporter metabolism pathway and carbohydrate digestion and absorption were substantially downregulated. The results of this study suggest that AIS affects the gut microbiota and plasma metabolites in Tibetan miniature pigs and that faecal microbiota transplantation could be a potential therapeutic approach for AIS.

Ketamine reduces remifentanil-induced postoperative hyperalgesia mediated by CaMKII-NMDAR in the primary somatosensory cerebral cortex region in mice.

Remifentanil is commonly used clinically for perioperative pain relief, but it may induce postoperative hyperalgesia. Low doses of ketamine have remained a common choice in clinical practice, but the mechanisms of ketamine have not yet been fully elucidated. In this study, we examined the possible effects of ketamine on calcium/calmodulin-dependent protein kinase II α (CaMKIIα) and N-methyl-d-aspartate receptor (NMDAR) subunit NR2B in a mouse model of remifentanil-induced postoperative hyperalgesia (RIPH) in the primary somatosensory cerebral cortex (SI) region. The paw withdrawal mechanical threshold (PWMT) and paw withdrawal thermal latency (PWTL) were used to assess mechanical allodynia and thermal hyperalgesia, respectively, before and after intraoperative remifentanil administration. Before surgery, mice received intrathecal injections of the following drugs: ketamine, NMDA, BayK8644 (CaMKII activator), and KN93 (CaMKII inhibitor). Immunofluorescence was performed to determine the anatomical location and expression of activated CaMKIIα, phosphorylated CaMKIIα (p-CaMKIIα). Additionally, western blotting was performed to assess p-CaMKIIα and NMDAR expression levels in the SI region. Remifentanil decreased the PWMT and PWTL at 0.5 h, 2 h, and 5 h and increased p-CaMKIIα expression in the SI region. Ketamine increased the PWMT and PWTL and reversed the p-CaMKIIα upregulation. Both BayK8644 and NMDA reversed the effect of ketamine, decreased the PWMT and PWTL, and upregulated p-CaMKIIα expression. In contrast, KN93 enhanced the effect of ketamine by reducing hyperalgesia and downregulating p-CaMKIIα expression. These results suggested that ketamine reversed RIPH by inhibiting the phosphorylation of CaMKIIα and the NMDA receptor in the SI region in mice.