Post-ischaemic silencing of p66Shc reduces ischaemia/reperfusion brain injury and its expression correlates to clinical outcome in stroke.

AIM: Constitutive genetic deletion of the adaptor protein p66(Shc) was shown to protect from ischaemia/reperfusion injury. Here, we aimed at understanding the molecular mechanisms underlying this effect in stroke and studied p66(Shc) gene regulation in human ischaemic stroke. METHODS AND RESULTS: Ischaemia/reperfusion brain injury was induced by performing a transient middle cerebral artery occlusion surgery on wild-type mice. After the ischaemic episode and upon reperfusion, small interfering RNA targeting p66(Shc) was injected intravenously. We observed that post-ischaemic p66(Shc) knockdown preserved blood-brain barrier integrity that resulted in improved stroke outcome, as identified by smaller lesion volumes, decreased neurological deficits, and increased survival. Experiments on primary human brain microvascular endothelial cells demonstrated that silencing of the adaptor protein p66(Shc) preserves claudin-5 protein levels during hypoxia/reoxygenation by reducing nicotinamide adenine dinucleotide phosphate oxidase activity and reactive oxygen species production. Further, we found that in peripheral blood monocytes of acute ischaemic stroke patients p66(Shc) gene expression is transiently increased and that this increase correlates with short-term neurological outcome. CONCLUSION: Post-ischaemic silencing of p66(Shc) upon reperfusion improves stroke outcome in mice while the expression of p66(Shc) gene correlates with short-term outcome in patients with ischaemic stroke.

Tumour Necrosis Factor-α Inhibition Improves Stroke Outcome in a Mouse Model of Rheumatoid Arthritis.

Rheumatoid Arthritis (RA) is a chronic inflammatory disorder where incidence and severity of myocardial infarction are increased. Data on the incidence and outcome of stroke are conflicting. Thus, we investigated outcome after Ischemia/Reperfusion (I/R) brain injury in a mouse model of RA and assessed for the role of the tumour necrosis factor-α (TNF-α) inhibitor Infliximab herein. We used a TNF-α reliant mouse model of RA. RA and wildtype (WT) animals were treated with vehicle (RA/WT) or Infliximab (RA Infliximab) for 4 weeks, before undergoing I/R brain injury. RA-animals displayed larger strokes and poorer neurological performance. Immunohistochemistry on brain sections revealed increased numbers of resident and peripheral innate immune cells (microglia and macrophages); increased Blood-Brain-Barrier (BBB)-disruption; decreased levels of the tight junction proteins (TJPs) claudin-5 and occludin; increased expression of matrix-metalloproteinases (MMP)-3 and -9 and enhanced lipid peroxidation. Treatment with Infliximab corrected these alterations. We show that RA associates to worse stroke-outcome via exacerbated BBB degradation by decrease of the TJPs claudin-5 and occludin. We identified MMPs-3 and -9 and increased oxidative stress as potential mediators thereof. Increased numbers of resident and peripheral innate immune cells (microglia and macrophages) may in turn contribute to all these effects. Infliximab-treatment restored the phenotype of RA-mice to baseline. Our data provide evidence clearly linking RA to adverse stroke-outcome in mice and indicate an approved TNF-α inhibitor as a potential strategy to reduce stroke-burden in this setting.

Omega-3 fatty acids predict recurrent venous thromboembolism or total mortality in elderly patients with acute venous thromboembolism.

Essentials The role of omega-3 fatty acids (n-3 FAs) in recurrent venous thromboembolism (VTE) is unknown. Association of n-3 FAs with recurrent VTE or total mortality was investigated in 826 patients. Whole blood n-3 FAs were inversely correlated with recurrent VTE or total mortality. Major and non-major bleeding was not increased in patients with higher levels of n-3 FAs. SUMMARY: Background The role of omega-3 fatty acids (n-3 FAs) in recurrent venous thromboembolism (VTE) remains unknown. Objectives To investigate the association of n-3 FAs with recurrent VTE or total mortality at 6 months and 3 years. Methods N-3 FAs were assessed in 826 patients aged ≥ 65 years, categorized into low, medium and high based on the 25th and 75th percentile. Mean follow-up was 29 months. Results At 6 months, subjects with medium (adjusted hazard ratio [HR], 0.37; 95% confidence interval [CI], 0.22-0.62) and high n-3 FA levels (adjusted HR, 0.36; 95% CI, 0.20-0.67) were less likely to develop recurrent VTE or total mortality, compared with those with low n-3 FAs. At 3 years, medium levels (adjusted HR, 0.67; 95% CI, 0.47-0.96) were associated with lower risk of recurrent VTE or total mortality. As compared with low n-3 FAs, the adjusted sub-hazard ratio [SHR] of recurrent VTE was 0.39 (95% CI, 0.15-0.99) in patients with medium and 0.17 (95% CI, 0.03-0.82) in patients with high n-3 FAs. The cumulative incidence of recurrent VTE was lower in the medium and high n-3 FA groups as compared with the low n-3 FA groups, but seems to have worn off after 3 years. The incidence of major and non-major bleeding was not greater in the high n-3 FA group. Conclusion Higher levels of n-3 FAs were associated with a lower risk of recurrent VTE or total mortality in elderly patients with VTE, but not with greater bleeding risk.