Dynamic change of collateral flow varying with distribution of regional blood flow in acute ischemic rat cortex

Abstract

Cerebral blood flow (CBF) is critical for the maintenance of cerebral function by guaranteed constant oxygen and glucose supply to brain. Collateral channels (CCs) are recruited to provide alternatives to CBF to ischemic regions once the primary vessel is occluded during ischemic stroke. However, the knowledge of the relationship between dynamic evolution of collateral flow and the distribution of regional blood flow remains limited. In this study, laser speckle imaging was used to assess dynamic changes of CCs and regional blood flow in a rat cortex with permanent middle cerebral artery occlusion (MCAo). We found that CCs immediately provided blood flow to ischemic territories after MCAo. More importantly, there were three kinds of dynamic changes of CCs during acute stroke: persistent CC, impermanent CC, and transient CC, respectively, related to different distributions of regional blood flow. Although there was the possible occurrence of peri-infarct depolarization (PID) during ischemia, there was no obvious significance about the onset time and duration of CCs between rats with and without PID. These results suggest that the initial arising of CCs does not ensure their persistence, and that collateral flow could be varied with distribution of regional blood flow in acute ischemic stroke, which may facilitate the understanding of collateral recruitment and promote the development of collateral therapeutics in the future.

Optical coherence tomography based microangiography provides an ability to longitudinally image arteriogenesis in vivo

“…It is therefore desirable to use a non-invasive in vivo imaging technology to study the process of arteriogenesis. Laser speckle perfusion imaging (LSI) has been explored to reveal the dynamic change in the cortical collateral circulation in rodent models during acute ischemic stroke (Wang, et al, 2012). However, the spatial resolution of LSI is inadequate to visualize the detailed collateral remodeling of small vessels within localized regions.…”

Intracranial Pressure and Collateral Blood Flow

“…7,[16][17][18][19][20][21] The degree of retrograde flow is proportional to regional cerebral blood flow within the MCA territory. 19 In…”

“…7,16 Second, collaterals represent a subsidiary vascular network able to provide retrograde perfusion to the ischemic territory during major vessel occlusion. [16][17][18][19] Collateral blood flow changes from bidirectional to unidirectional, toward the occluded arterial territory (MCA), and increases in velocity. 7,[16][17][18][19][20][21] The degree of retrograde flow is proportional to regional cerebral blood flow within the MCA territory.…”

How temporal evolution of intracranial collaterals in acute stroke affects clinical outcomes

“…Analogous to rat studies, the recruited collaterals evaluated in our study were persistent rather than impermanent or transient. 12 In animal studies, if this subacute response resulted in hyperperfusion at day 4, it was associated with a larger final infarct size as compared to animals with maximal hyperperfusion at day 1. 23 Our study shows that collateral recruitment on the day 2 scan per se is an independent predictor of higher mortality, but not functional outcomes.…”

“…In rat studies, 3 different types of collaterals have been identified: transient collaterals that could be seen immediately after the stroke and last less than 90 minutes; impermanent collaterals that disappear after 90-150 minutes; and persistent collaterals, which can be seen for longer periods. 12 There is a dearth of literature on the temporal evolution of leptomeningeal collaterals in AIS in humans. Perhaps this is due to the emergent nature of AIS, which is not conducive to serial imaging required for elucidating this phenomenon.…”