Stage 1 Registered Report: Effect of deficient phagocytosis on neuronal survival and neurological outcome after temporary middle cerebral artery occlusion (tMCAo)

Abstract

Stroke is a major cause of death and disability worldwide. In addition to neuronal death resulting directly from energy depletion due to lack of blood supply, inflammation and microglial activation following ischemic brain injury has been increasingly recognized to be a key contributor to the pathophysiology of cerebrovascular disease. However, our understanding of the cross talk between the ischemic brain and the immune system is limited. Recently, we demonstrated that following focal ischemia, death of mature viable neurons can be executed through phagocytosis by microglial cells or recruited macrophages, i.e. through phagoptosis. It was shown that inhibition of phagocytic signaling pathways following endothelin-1 induced focal cerebral ischemia leads to increased neuronal survival and neurological recovery. This suggests that inhibition of specific phagocytic pathways may prevent neuronal death during cerebral ischemia. To further explore this potential therapeutic target, we propose to assess the role of phagocytosis in an established model of temporary (45min) middle cerebral artery occlusion, and to evaluate neuronal survival and neurological recovery in mice with deficient phagocytosis.

Reporting animal research: Explanation and elaboration for the ARRIVE guidelines 2.0

“…Secondary outcomes constitute Rotarod performance, stroke volume (quantified on MR imaging or brain sections, respectively), diffusion tensor imaging (DTI) connectome mapping, and histological analyses to measure neuronal and microglial densities, and phagocytic activity…. The study is designed with 80% power to detect a relative 25% difference in pellet-reaching performance in the Staircase test’ [ 96 ].…”

Paracrine Interleukin 6 Induces Cerebral Remodeling at Early Stages After Unilateral Common Carotid Artery Occlusion in Mice

“…Tests were performed on days 2, 7, and 14 after unilateral CCAo. Staircase skilled pellet reaching test was performed daily for 21 days of training before and up to 21 days after ligation of the CCA for conditioning as described previously (13). Outcome was measured as relative performance compared to the individual performance before surgery for each forepaw.…”

Refining humane endpoints in mouse models of disease by systematic review and machine learning-based endpoint definition

“…No animals were used for this study. Rather, all data analyzed in this study were sourced from the authors' previously published and unpublished results using a middle cerebral artery occlusion (MCAo) stroke model and a lipopolysaccharide (LPS)-induced systemic inflammation model, respectively (Hoffmann et al, 2015;Donath et al, 2016;Koch et al, 2017;Emmrich et al, tency in endpoint determination. However, the varying nature of animal models and disease progression, lack of reporting these details in the literature, lack of standardized evaluation protocols, and heterogeneity of endpoints published in the literature make it difficult to accurately determine and apply humane endpoints (Franco et al, 2012).…”