Dopatka, M. | Search bioRxiv

bioRxiv2024

A randomized, controlled, two-center preclinical trial assessing the efficacy of a new benzodiazepine-dihydropyridine hybrid molecule (JM-20) in rodent models of ischemic stroke

JM-20 is a novel multifunctional benzodiazepine molecule with potent neuroprotective effects in rat focal cerebral ischemia. To confirm previous results obtained in single laboratories with small sample sizes, and to provide a robust preclinical evidence base for potential clinical development in stroke, we have performed a two-center preclinical trial with sufficiently large group sizes to detect relevant effects, minimizing biases in experimental design as much as possible (randomization, blinding, predefined in- and exclusion criteria) and increasing external and construct validities by performing experimental focal cerebral ischemia by different surgeons in two different laboratories on two continents, including two species (480 mice and 55 rats), different suppliers, young, young adult, and mature adult animals (range 2 -16 months) as well as comorbid animals (diabetes). While JM-20 improved functional outcomes after middle cerebral artery occlusion in young adult mice at day 7 and appeared to reduce mortality (not statistically significant), it had no effect in mature adult or comorbid (STZ-induced diabetes) mice. Effect sizes, where statistically significant, were modest, and much lower than those reported in the previous studies. Meta-analysis of all individual mouse data did not reveal statistically significant different functional outcomes or mortalities between vehicle- and JM-20-treated animals, although neuroscores and survival were slightly better in JM-20-treated animals. In the less severe model of permanent cortical focal cerebral ischemia in rats, JM-20 significantly reduced brain infarction. We conclude that we were able to confirm the neuroprotective potential of JM-20. However, effect sizes were substantially lower as previously described in small, monocentric trials. Further study is needed to determine whether JM-20 could be effective in less severe cases of focal cerebral ischemia or when used in combination with thrombolysis.

pharmacology and toxicology↗

bioRxiv2023

Pial collaterals develop through mosaic colonization of capillaries by arterial and microvascular endothelial cells

Collaterals are unique blood vessels present in many healthy tissues that cross-connect distal-end arterioles of adjacent arterial trees, thus providing alternate routes of perfusion. Stroke patients with superior pial collateral flow respond better to treatments and present with an overall improved prognostic outcome. However, how pial collaterals develop in the embryo and how they reactivate upon stroke remains unclear. Here, using lineage tracing in combination with three-dimensional imaging, we demonstrate that mouse embryos employ a novel mechanism to build pial collaterals, distinct from their outward remodeling following stroke. Endothelial cells (ECs) of arterial and microvascular origin invade already existing pre-collateral vascular structures in a process which we termed mosaic colonization. Arterialization of these pre-collateral vascular segments happens concurrently with mosaic colonization. Despite having a smaller proliferative capacity, embryonic arterial cells represent the majority of cells that migrate to form nascent collaterals; embryonic microvascular cells, despite their higher proliferative potential, form only about a quarter of collateral endothelial cells. Moreover, postnatal collateral growth relies much more on self-replenishment of arterial cells than on microvascular contribution. Following ischemic injury, pial collateral outward remodeling relies on local cell proliferation rather than recruitment of non-arterial cells. Together, these findings establish distinct cellular mechanisms underlying pial collateral development and ischemic remodeling, raising the prospect for future research to identify novel, collateral-specific therapeutic strategies for ischemic stroke.

developmental biology↗