Inflammatory Brain Injury After Cardiopulmonary Bypass: Is It Real?

Effects of TLR3 and TLR9 Signaling Pathway on Brain Protection in Rats Undergoing Sevoflurane Pretreatment during Cardiopulmonary Bypass

OBJECTIVE

To investigate the effects of TLR3 and TLR9 signaling pathway on brain injury during CPB in rats pretreated with sevoflurane and its possible molecular mechanism.

METHODS

SD rats were randomly assigned to sham group, CPB group, and Sev group. Brain tissue was obtained at before CPB (T0), at CPB for 30 minutes (T1), 1 hour after CPB (T3), and 3 hours after CPB (T5). ELISA was used to measure S100-β and IL-6. Western blot was utilized to determine TLR3 and TLR9 expression. TUNEL was applied to detect neuronal apoptosis.

RESULTS

Compared with CPB group, at T1, at termination after 1 hour of CPB (T2), T3, 2 hours after CPB (T4) and T5, S100-β and IL-6 decreased in Sev group. Compared with CPB group, IFN-β were increased in Sev group, except T0. Compared with CPB group, TLR3 expression increased, and TLR9 and NF-κB decreased in Sev group. The apoptotic neurons were less in Sev group than in CPB group (P < 0.05).

CONCLUSION

Sevoflurane intervention can activate TLR3 and TLR9 signaling pathway, upregulate TLR3 expression and downstream TRIF expression, decrease TLR9 expression, and downregulate downstream NF-κB expression in CPB rat models, thereby mitigating brain injury induced by inflammatory response during CPB.

Cardiopulmonary Bypass-Induced Inflammatory Response: Pathophysiology and Treatment

OBJECTIVES

The objectives of this review are to discuss the pathophysiology of the pro-inflammatory response to the cardiopulmonary bypass circuit, the impact of ischemia reperfusion injury on post-operative organ function, the compensatory anti-inflammatory response and the evidence for immune-modulatory strategies and their impact on outcomes.

DATA SOURCE

MEDLINE, PubMed.

CONCLUSION

Innovations such as the development of more biocompatible surfaces and miniaturized circuits, as well as the increasing expertise of surgeons, anesthesiologists and perfusionists has transformed cardiac surgery and the use of cardiopulmonary bypass into a relatively routine procedure with favorable outcomes. Despite these refinements, the attendant inflammatory response to bypass, ischemia reperfusion injury and the compensatory anti-inflammatory response contribute to post-operative morbidity and mortality. Additional studies are needed to further delineate the impact of immunomodulatory strategies on outcomes.

Inflammatory Response in Patients under Coronary Artery Bypass Grafting Surgery and Clinical Implications: A Review of the Relevance of Dexmedetomidine Use

Despite the fact that coronary artery bypass grafting surgery (CABG) with cardiopulmonary bypass (CPB) prolongs life and reduces symptoms in patients with severe coronary artery diseases, these benefits are accompanied by increased risks. Morbidity associated with cardiopulmonary bypass can be attributed to the generalized inflammatory response induced by blood-xenosurfaces interactions during extracorporeal circulation and the ischemia/reperfusion implications, including exacerbated inflammatory response resembling the systemic inflammatory response syndrome (SIRS). The use of specific anesthetic agents with anti-inflammatory activity can modulate the deleterious inflammatory response. Consequently, anti-inflammatory anesthetics may accelerate postoperative recovery and better outcomes than classical anesthetics. It is known that the stress response to surgery can be attenuated by sympatholytic effects caused by activation of central (α-)2-adrenergic receptor, leading to reductions in blood pressure and heart rate, and more recently, that they can have anti-inflammatory properties. This paper discusses the clinical significance of the dexmedetomidine use, a selective (α-)2-adrenergic agonist, as a coadjuvant in general anesthesia. Actually, dexmedetomidine use is not in anesthetic routine, but this drug can be considered a particularly promising agent in perioperative multiple organ protection.

Can postoperative cognitive dysfunction be avoided?

Postoperative cognitive dysfunction (POCD) refers to a postoperative decline in cognitive function compared with preoperative cognitive function. Diagnosis requires pre- and postoperative testing, the latter of which is usually performed both 7 days and 3 months postoperatively. Although several risk factors for POCD have been described, age is the only consistently reported risk factor. Postoperative cognitive dysfunction is often transient. It may last several months, and is associated with leaving the labor market prematurely and increased mortality. As the pathophysiology of POCD is still a matter of debate and is likely to be multifactorial, there are no widely accepted prophylactic and therapeutic interventions. In this article, we discuss POCD's definition, risk factors, long-term significance, and pathophysiology. We also present data on prophylactic interventions that have been investigated in clinical trials.

Animal models of cardiopulmonary bypass: development, applications, and impact

Neurologic and neurocognitive complications after cardiac surgery have been reported repeatedly. To better understand its etiology and design protective strategies, small animal models have been developed. This study describes the development of a survival rat cardiopulmonary bypass (CPB) model, along with the introduction of an appropriately sized oxygenator. This model led the way for even more complicated models with CPB, facilitating full cardiac arrest with anterograde cardioplegia administration, air embolization, and deep hypothermic circulatory arrest. In addition, the results of several of those rat CPB studies are summarized and their preclinical relevance is pointed out.