LOX-1 and MMP-9 Inhibition Attenuates the Detrimental Effects of Delayed rt-PA Therapy and Improves Outcomes After Acute Ischemic Stroke

BACKGROUND

Acute ischemic stroke triggers endothelial activation that disrupts vascular integrity and increases hemorrhagic transformation leading to worsened stroke outcomes. rt-PA (recombinant tissue-type plasminogen activator) is an effective treatment; however, its use is limited due to a restricted time window and hemorrhagic transformation risk, which in part may involve activation of MMPs (matrix metalloproteinases) mediated through LOX-1 (lectin-like oxLDL [oxidized low-density lipoprotein] receptor 1). This study's overall aim was to evaluate the therapeutic potential of novel MMP-9 (matrix metalloproteinase 9) ± LOX-1 inhibitors in combination with rt-PA to improve stroke outcomes.

METHODS

A rat thromboembolic stroke model was utilized to investigate the impact of rt-PA delivered 4 hours poststroke onset as well as selective MMP-9 (JNJ0966) ±LOX-1 (BI-0115) inhibitors given before rt-PA administration. Infarct size, perfusion, and hemorrhagic transformation were evaluated by 9.4-T magnetic resonance imaging, vascular and parenchymal MMP-9 activity via zymography, and neurological function was assessed using sensorimotor function testing. Human brain microvascular endothelial cells were exposed to hypoxia plus glucose deprivation/reperfusion (hypoxia plus glucose deprivation 3 hours/R 24 hours) and treated with ±tPA and ±MMP-9 ±LOX-1 inhibitors. Barrier function was assessed via transendothelial electrical resistance, MMP-9 activity was determined with zymography, and LOX-1 and barrier gene expression/levels were measured using qRT-PCR (quantitative reverse transcription PCR) and Western blot.

RESULTS

Stroke and subsequent rt-PA treatment increased edema, hemorrhage, MMP-9 activity, LOX-1 expression, and worsened neurological outcomes. LOX-1 inhibition improved neurological function, reduced edema, and improved endothelial barrier integrity. Elevated MMP-9 activity correlated with increased edema, infarct volume, and decreased neurological function. MMP-9 inhibition reduced MMP-9 activity and LOX-1 expression. In human brain microvascular endothelial cells, LOX-1/MMP-9 inhibition differentially attenuated MMP-9 levels, inflammation, and activation following hypoxia plus glucose deprivation/R.

CONCLUSIONS

Our findings indicate that LOX-1 inhibition and ± MMP-9 inhibition attenuate negative aspects of ischemic stroke with rt-PA therapy, thus resulting in improved neurological function. While no synergistic effect was observed with simultaneous LOX-1 and MMP-9 inhibition, a distinct interaction is evident.

Outcomes of decompressive craniectomy for large territory cerebral infarction with and without prior reperfusion: a multicentre retrospective review

PURPOSE

Reperfusion therapy has greatly improved outcomes of ischaemic stroke but remains associated with haemorrhagic conversion and early deterioration in a significant proportion of patients. Outcomes in terms of function and mortality are mixed and the evidence for decompressive craniectomies (DC) in this context remains sparse. We aim to investigate the clinical efficacy of DC in this group of patients compared to those without prior reperfusion therapy.

METHODS

A multicentre retrospective study was conducted between 2005 and 2020, and all patients with DC for large territory infarctions were included. Outcomes in terms of inpatient and long-term modified Rankin scale (mRS) and mortality were assessed at various time points and compared using both univariable and multivariable analyses. Favourable mRS was defined as 0-3.

RESULTS

There were 152 patients included in the final analysis. The cohort had a mean age of 57.5 years and median Charlson comorbidity index of 2. The proportion of preoperative anisocoria was 15.1%, median preoperative Glasgow coma scale was 9, the ratio of left-sided stroke was 40.1%, and ICA infarction was 42.8%. There were 79 patients with prior reperfusion and 73 patients without. After multivariable analysis, the proportion of favourable 6-month mRS (reperfusion, 8.2%; no reperfusion, 5.4%) and 1-year mortality (reperfusion, 26.7%; no reperfusion, 27.3%) were similar in both groups. Subgroup analysis of thrombolysis and/or thrombectomy against no reperfusion was also unremarkable.

CONCLUSION

Reperfusion therapy prior to DC performed for large territory cerebral infarctions does not affect the functional outcome and mortality in a well-selected patient population.