scholarly journals CBF oscillations induced by trigeminal nerve stimulation protect the pericontusional penumbra in traumatic brain injury complicated by hemorrhagic shock

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chunyan Li ◽  
Kevin A. Shah ◽  
Keren Powell ◽  
Yi-Chen Wu ◽  
Wayne Chaung ◽  
...  

AbstractTraumatic peri-contusional penumbra represents crucial targets for therapeutic interventions after traumatic brain injury (TBI). Current resuscitative approaches may not adequately alleviate impaired cerebral microcirculation and, hence, compromise oxygen delivery to peri-contusional areas. Low-frequency oscillations in cerebral blood flow (CBF) may improve cerebral oxygenation in the setting of oxygen deprivation. However, no method has been reported to induce controllable oscillations in CBF and it hasn’t been applied as a therapeutic strategy. Electrical stimulation of the trigeminal nerve (TNS) plays a pivotal role in modulating cerebrovascular tone and cerebral perfusion. We hypothesized that TNS can modulate CBF at the targeted frequency band via the trigemino-cerebrovascular network, and TNS-induced CBF oscillations would improve cerebral oxygenation in peri-contusional areas. In a rat model of TBI complicated by hemorrhagic shock, TNS-induced CBF oscillations conferred significant preservation of peri-contusional tissues leading to reduced lesion volume, attenuated hypoxic injury and neuroinflammation, increased eNOS expression, improved neurological recovery and better 10-day survival rate, despite not significantly increasing CBF as compared with those in immediate and delayed resuscitation animals. Our findings indicate that low-frequency CBF oscillations enhance cerebral oxygenation in peri-contusional areas, and play a more significant protective role than improvements in non-oscillatory cerebral perfusion or volume expansion alone.

2021 ◽  
Author(s):  
Chunyan Li ◽  
Kevin A. Shah ◽  
Keren Powell ◽  
Yi-Chen Wu ◽  
Wayne Chaung ◽  
...  

Abstract Traumatic peri-contusional penumbra represents crucial targets for therapeutic interventions after traumatic brain injury (TBI). Current resuscitative approaches may not adequately alleviate impaired cerebral microcirculation and, hence, compromise oxygen delivery to peri-contusional areas. Low-frequency oscillations in cerebral blood flow (CBF) may improve cerebral oxygenation in the setting of oxygen deprivation. However, no method has been reported to induce controllable oscillations in CBF and it hasn’t been applied as a therapeutic strategy. Electrical stimulation of the trigeminal nerve (TNS) plays a pivotal role in modulating cerebrovascular tone and cerebral perfusion. We hypothesized that TNS can modulate CBF at the targeted frequency band via the trigemino-cerebrovascular network, and TNS-induced CBF oscillations would improve cerebral oxygenation in peri-contusional areas. In a rat model of TBI complicated by hemorrhagic shock, TNS-induced CBF oscillations conferred significant preservation of peri-contusional tissues leading to reduced lesion volume, attenuated hypoxic injury and neuroinflammation, increased eNOS expression, improved neurological recovery and better 10-day survival rate, despite not significantly increasing CBF as compared with those in immediate and delayed resuscitation animals. Our findings indicate that low-frequency CBF oscillations enhance cerebral oxygenation in peri-contusional areas, and play a more significant protective role than improvements in non-oscillatory cerebral perfusion or volume expansion alone.


2021 ◽  
Author(s):  
Hibah O Awwad ◽  
Andria Hedrick ◽  
Alex Mdzinarishvili ◽  
Hailey Houson ◽  
Kelly Standifer ◽  
...  

Traumatic brain injury (TBI)is a major cause of death and disability worldwide. Hemorrhagic shock (HS) aggravates tissue injury and complicates TBI recovery. We studied the combined insult of mild TBI and HS and investigated the impact of varying loss of blood volume on neurologic deficit and brain lesion volume. A novel positron emission tomography (PET) technique was employed to monitor tissue injury. Male Sprague Dawley rats received mTBI by controlled cortical impact (CCI) followed by withdrawal of 0%, 30-40%, 45%, or 50% of blood (mTBI, mTBI+HS≤40%, mTBI+HS45%, and mTBI+HS50%, respectively). Neurological deficit (mNSS= 5.6, 7.6, and 12.3) and mortality (2/12, 2/6, and 7/12) were higher in mTBI+HS≤40%, mTBI+HS45%, and mTBI+HS50%, than in mTBI alone rats (no death; mNSS=3.3). Histologic lesion size increased 3.5-fold in mTBI+HS50% compared to mTBI alone and the infarct-avid PET agent 18F-fluorodeoxyglucaric acid (FGA) proportionately detected tissue necrosis in mTBI+HS50% rats. Based on these results, we conclude that HS aggravates mTBI-induced neurological deficits, tissue injury and mortality. PET using 18F-FGA as an imaging marker can detect the extent of injury in a non-invasive manner.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cynthia R. Muller ◽  
Vasiliki Courelli ◽  
Alfredo Lucas ◽  
Alexander T. Williams ◽  
Joyce B. Li ◽  
...  

AbstractTraumatic brain injury (TBI) is often accompanied by hemorrhage, and treatment of hemorrhagic shock (HS) after TBI is particularly challenging because the two therapeutic treatment strategies for TBI and HS often conflict. Ischemia/reperfusion injury from HS resuscitation can be exaggerated by TBI-induced loss of autoregulation. In HS resuscitation, the goal is to restore lost blood volume, while in the treatment of TBI the priority is focused on maintenance of adequate cerebral perfusion pressure and avoidance of secondary bleeding. In this study, we investigate the responses to resuscitation from severe HS after TBI in rats, using fresh blood, polymerized human hemoglobin (PolyhHb), and lactated Ringer’s (LR). Rats were subjected to TBI by pneumatic controlled cortical impact. Shortly after TBI, HS was induced by blood withdrawal to reduce mean arterial pressure (MAP) to 35–40 mmHg for 90 min before resuscitation. Resuscitation fluids were delivered to restore MAP to ~ 65 mmHg and animals were monitored for 120 min. Increased systolic blood pressure variability (SBPV) confirmed TBI-induced loss of autoregulation. MAP after resuscitation was significantly higher in the blood and PolyhHb groups compared to the LR group. Furthermore, blood and PolyhHb restored diastolic pressure, while this remained depressed for the LR group, indicating a loss of vascular tone. Lactate increased in all groups during HS, and only returned to baseline level in the blood reperfused group. The PolyhHb group possessed lower SBPV compared to LR and blood groups. Finally, sympathetic nervous system (SNS) modulation was higher for the LR group and lower for the PolyhHb group compared to the blood group after reperfusion. In conclusion, our results suggest that PolyhHb could be an alternative to blood for resuscitation from HS after TBI when blood is not available, assuming additional testing demonstrate similar favorable results. PolyhHb restored hemodynamics and oxygen delivery, without the logistical constraints of refrigerated blood.


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