The impact of acute remote ischaemic preconditioning on cerebrovascular function

Abstract

Purpose Remote ischaemic preconditioning (RIPC) refers to the protection conferred to tissues and organs via brief periods of ischaemia in a remote vascular territory, including the brain. Recent studies in humans report that RIPC provides neuroprotection against recurrent (ischaemic) stroke. To better understand the ability of RIPC to improve brain health, the present study explored the potential for RIPC to acutely improve cerebrovascular function. Methods Eleven young healthy (females n = 6, age; 28.1 ± 3.7 years) and 9 older individuals (females n = 4, age 52.5 ± 6.7 years) at increased risk for stroke (cardiovascular disease risk factors) underwent assessments of cerebrovascular function, assessed by carbon dioxide (CO 2) reactivity and cerebral autoregulation during normo-and hypercapnia (5% CO 2) following 40 mins of bilateral arm RIPC or a sham condition. Squat-to-stand manoeuvres were performed to induce changes in blood pressure to assess cerebral autoregulation (0.10 Hz) and analysed via transfer function. Results We found no change in middle cerebral artery velocity or blood pressure across 40 mins of RIPC. Application of RIPC resulted in no change in CO 2 reactivity slopes (sham vs RIPC, 1.97 ± 0.88 vs 2.06 ± 0.69 cm/s/mmHg P = 0.61) or parameters of cerebral autoregulation during normocapnia (sham vs RIPC, normalised gain%, 1.27 ± 0.25 vs 1.22 ± 0.35, P = 0.46). Conclusion This study demonstrates that a single bout of RIPC does not influence cerebrovascular function acutely in healthy individuals, or those at increased cardiovascular risk. Given the previously reported protective role of RIPC on stroke recurrence in humans, it is possible that repeated bouts of RIPC may be necessary to impart beneficial effects on cerebrovascular function.

Glial Cells as Therapeutic Approaches in Brain Ischemia-Reperfusion Injury

“…Remote ischemic preconditioning (RIPreC), usually induced by blocking blood flow to the limbs, has repeatedly proved to induce tolerance against subsequent I/R damage in animal models and clinical trials [ 181 ]. In fact, it is known that patients with a history of peripheral vascular disease (PVD) present lower infarct volumes, better outcomes, and lower mortality rates after an ischemic insult [ 182 ].…”

Can exercise training enhance the repeated remote ischaemic preconditioning stimulus on peripheral and cerebrovascular function in high-risk individuals?

“…A small number of studies have shown that repeated rIPC can increase cerebral blood flow (CBF) in stroke patients and importantly reduce the rate of stroke reoccurrence (Meng et al 2012 , 2015 ). Nevertheless, a recent study from our group, attempting to understand how rIPC exerts its effects on the cerebrovasculature, demonstrated that a single bout of rIPC has a negligible impact on CBF velocity (CBFv) or dynamic cerebral autoregulation (dCA) as a marker of cerebrovascular function (Carter et al 2020 ). This observation may relate to the relatively small ‘dose’ of a single exposure to rIPC.…”

“…Therefore, we examined the impact of 7-daily repeated rIPC intervention in individuals with type 2 diabetes, but found no impact on cerebrovascular function (Maxwell et al 2019 ). A number of important methodological differences are evident between our recent studies (Carter et al 2020 ; Maxwell et al 2019 ) and the previous studies showing benefits on cerebrovascular health (Meng et al 2012 , 2015 ; Mi et al 2016 ; Wang et al 2017 ), primarily; participant population, length of rIPC intervention and measurement techniques. The length of the intervention and the number of rIPC bouts performed over the intervention, collectively the dose of rIPC is an important aspect to consider.…”

Review Cerebral Ischemic Tolerance and Preconditioning: Methods, Mechanisms, Clinical Applications, and Challenges

“…Obviously, the most convenient and safest strategy of performing RIPreC should be on limbs when this preconditioning strategy is considered to be clinically used ( 28 ). Remote ischemic limb(s) preconditioning (limb-RIPreC), usually via binding the cuff to the distal limb(s) and inflating the cuff to a pressure that blocks the blood perfusion of the limb(s), has been used to effectively induce ischemic tolerance against subsequent I/R damage in animal experiments ( 223 ) and clinical trials over decades ( 28 , 226 ). It has been found that acute ischemic stroke patients with a history of peripheral vascular disease (PVD) have significantly smaller infarct volumes, better clinical outcomes, and a lower mortality rate than those without PVD ( 227 ), also confirming the efficiency of limb-RIPreC.…”