A synthetic tryptophan metabolite reduces hemorrhagic area and inflammation after pulmonary radiofrequency ablation in rabbit nonneoplastic lungs

MSC therapy ameliorates experimental gouty arthritis hinting an early COX-2 induction

Objective

The specific effect of Adipose-Derived Mesenchymal Stem Cells (Ad-MSC) on acute joint inflammation, where the response mostly depends on innate immunity activation, remains elusive. The pathogenesis of gouty arthritis, characterized by the deposition of monosodium urate (MSU) crystals in the joints, associated to acute flares, has been associated to NLRP3 inflammasome activation and subsequent amplification of the inflammatory response. Our aim was to study the effect of human Ad-MSC administration in the clinical inflammatory response of rabbits after MSU injection, and the molecular mechanisms involved.

Methods

Ad-MSC were administered by intraarterial route shortly after intraarticular MSU crystal injections. Joint and systemic inflammation was sequentially studied, and the mechanisms involved in NLRP3 inflammasome activation, and the synthesis of inflammatory mediators were assessed in the synovial membranes 72h after insult. Ad-MSC and THP-1-derived macrophages stimulated with MSU were co-cultured in transwell system.

Results

A single systemic dose of Ad-MSC accelerated the resolution of local and systemic inflammatory response. In the synovial membrane, Ad-MSC promoted alternatively M2 macrophage presence, inhibiting NLRP3 inflammasome and inducing the production of anti-inflammatory cytokines, such as IL-10 or TGF-β, and decreasing nuclear factor-κB activity. Ad-MSC induced a net anti-inflammatory balance in MSU-stimulated THP-1 cells, with a higher increase in IL-10 and IDO expression than that observed for IL-1β and TNF.

Conclusion

Our in vivo and in vitro results showed that a single systemic dose of Ad-MSC decrease the intensity and duration of the inflammatory response by an early local COX-2 upregulation and PGE2 release. Ad-MSCs suppressed NF-kB activity, NLRP3 inflammasome, and promoted the presence of M2 alternative macrophages in the synovium. Therefore, this therapeutic approach could be considered as a pharmacological alternative in patients with comorbidities that preclude conventional treatment.

Higher lactate and purine metabolite levels in erythrocyte-rich fresh venous thrombus: Potential markers for early deep vein thrombosis

BACKGROUND

Thrombolytic therapy is effective in fresh deep vein thrombosis (DVT) although the benefit may fall below the risk of bleeding in non-fresh thrombosis. Markers reflecting fresh DVT have not been established. The present study aims to identify metabolites reflecting fresh venous thrombus and their role in thrombus formation.

METHODS

Metabolites of rabbit venous blood and jugular venous thrombus 4 h after thrombus induction were analysed using electrophoresis-time of flight mass spectrometry. The effects of the altered metabolites on blood coagulation and platelet aggregation were assessed by using rotation thromboelastometry and platelet aggregometer. Cellular contents and glucose transporter (Glut)-1 expression in aspirated human DVT samples were pathologically analysed.

RESULTS

Metabolome analysis identified 226 metabolites (133 cationic and 93 anionic metabolites). Largely altered 18 metabolites (thrombus/blood ratio: >5 or <0.5) included glycolytic metabolites, redox-related metabolites, purine nucleotides and tryptophan metabolites. Among the metabolites with >5-fold increase, lactic acid was most abundant and guanine modestly enhanced whole blood clotting with thromboelastometry. Lactic acid and adenosine monophosphate inhibited collagen-induced platelet aggregation. Human DVTs were rich in erythrocytes expressing Glut-1. The erythrocyte content and Glut-1 expression were negatively correlated with the time after onset of DVT.

CONCLUSIONS

Glycolysis-, purine-, and redox-related metabolites may reflect fresh erythrocyte-rich venous thrombus, and altered metabolites may affect venous thrombus formation. An increased level of lactate may reflect active glycolysis of thrombus cellular components, predominantly erythrocytes.