Systemically administered anti-TNF therapy ameliorates functional outcomes after focal cerebral ischemia

D C Anthony ,David E. Szymkowski ,Tomas Deierborg,Yvonne Couch,Maria-Louise Bergholdt Mortensen ,Leena Karimi,I L Sargent ,Chris Gardiner,Maria Ormhøj,Bettina Hjelm Clausen ,Géraldine Petit ,Bente Finsen,Nellie Anne Martin ,Matilda Degn,Kate Lykke Lambertsen ,Hanne Gredal

doi:10.1186/preaccept-2982253041347736

Abstract

The innate immune system contributes to the outcome after stroke, where neuroinflammation and post-stroke systemic immune depression are central features. Tumor necrosis factor (TNF), which exists in both a transmembrane (tm) and soluble (sol) form, is known to sustain complex inflammatory responses associated with stroke. We tested the effect of systemically blocking only solTNF versus blocking both tmTNF and solTNF on infarct volume, functional outcome and inflammation in focal cerebral ischemia. We used XPro1595 (a dominant-negative inhibitor of solTNF) and etanercept (which blocks both solTNF and tmTNF) to test the effect of systemic administration on infarct volume, functional recovery and inflammation after focal cerebral ischemia in mice. Functional recovery was evaluated after one, three and five days, and infarct volumes at six hours, 24 hours and five days after ischemia. Brain inflammation, liver acute phase response (APR), spleen and blood leukocyte profiles, along with plasma microvesicle analysis, were evaluated. We found that both XPro1595 and etanercept significantly improved functional outcomes, altered microglial responses, and modified APR, spleen T cell and microvesicle numbers, but without affecting infarct volumes. Our data suggest that XPro1595 and etanercept improve functional outcome after focal cerebral ischemia by altering the peripheral immune response, changing blood and spleen cell populations and decreasing granulocyte infiltration into the brain. Blocking solTNF, using XPro1595, was just as efficient as blocking both solTNF and tmTNF using etanercept. Our findings may have implications for future treatments with anti-TNF drugs in TNF-dependent diseases.

Highlights

The innate immune system contributes to the outcome after stroke, where neuroinflammation and post-stroke systemic immune depression are central features
Injected anti-Tumor necrosis factor (TNF) therapy does not affect infarct size after permanent focal cerebral ischemia Focal cerebral ischemia produced a cortical infarct, which was visible in toluidine blue solution (TB)-stained sections at six hours, 24 hours and five days after permanent middle cerebral artery occlusion (pMCAO) (Figure 1A)
Comparison of mean infarct volumes showed that anti-TNF therapy targeting either solTNF using XPro1595, or both solTNF and tmTNF using etanercept, did not affect infarct size at six hours (P = 0.79), 24 hours (P = 0.76) or five days (P = 0.92) after pMCAO (Figure 1B)

Summary

Introduction

The innate immune system contributes to the outcome after stroke, where neuroinflammation and post-stroke systemic immune depression are central features. Peri-spinal etanercept has been used with success in stroke and traumatic brain injury patients, where treatment resulted in neurological improvement [7,8] Their use is hampered by side effects, including increased risk of sepsis, demyelinating disease, neuropathies, heart failure and infections [9], which represents a considerable risk for stroke patients. Since etanercept inhibits both solTNF and tmTNF, this raises the possibility that solTNF-specific inhibitors, sparing tmTNF, have the potential to inhibit deleterious inflammation without compromising the immune system’s response to infections. The ability of XPro1595 to be tmTNF-sparing and solTNF-selective potentially makes XPro1595 a safer clinical drug than etanercept as it ensures that the role of tmTNF in immune function and myelin preservation is not compromised

Methods

Results

Discussion

Conclusion