Do S100beta protein level increases due to inflammation during cardiopulmonary bypass occur without any neurological deficit?

Neurocardiology: Cardiovascular Changes and Specific Brain Region Infarcts

There are complex and dynamic reflex control networks between the heart and the brain, including cardiac and intrathoracic ganglia, spinal cord, brainstem, and central nucleus. Recent literature based on animal model and clinical trials indicates a close link between cardiac function and nervous systems. It is noteworthy that the autonomic nervous-based therapeutics has shown great potential in the management of atrial fibrillation, ventricular arrhythmia, and myocardial remodeling. However, the potential mechanisms of postoperative brain injury and cardiovascular changes, particularly heart rate variability and the presence of arrhythmias, are not understood. In this chapter, we will describe mechanisms of brain damage undergoing cardiac surgery and focus on the interaction between cardiovascular changes and damage to specific brain regions.

Neuroprotective Strategies during Cardiac Surgery with Cardiopulmonary Bypass

Aortocoronary bypass or valve surgery usually require cardiac arrest using cardioplegic solutions. Although, in principle, in a number of cases beating heart surgery (so-called off-pump technique) is possible, aortic or valve surgery or correction of congenital heart diseases mostly require cardiopulmonary arrest. During this condition, the heart-lung machine also named cardiopulmonary bypass (CPB) has to take over the circulation. It is noteworthy that the invention of a machine bypassing the heart and lungs enabled complex cardiac operations, but possible negative effects of the CPB on other organs, especially the brain, cannot be neglected. Thus, neuroprotection during CPB is still a matter of great interest. In this review, we will describe the impact of CPB on the brain and focus on pharmacological and non-pharmacological strategies to protect the brain.

S100B is not a reliable prognostic index in paediatric TBI

BACKGROUND

As far as paediatric traumatic brain injury is concerned, it is difficult to quantify the extent of the primary insult, to monitor secondary changes and to predict neurological outcomes by means of the currently used diagnostic tools: physical examination, Glasgow Coma Scale (GCS) score and computed tomography. For this reason, several papers focused on the use of biochemical markers (S100B, neuron-specific enolase) to detect and define the severity of brain damage and predict outcome after traumatic head injury or cardiac arrest.

OBJECTIVE

The aim of this paper is measuring the range of S100B serum concentrations in children affected by traumatic brain injury and describing the possible roles of this protein in the reaction to trauma.

METHODS

Fifteen children aged 1-15 years were included in the study. Traumatic brain injury severity was defined by paediatric GCS score as mild (9 patients), moderate (2 patients) or severe (4 patients). Blood samples for S100B serum measurement were taken at emergency department admission and after 48 h.

RESULTS

The serum S100B concentration was higher in the group of severe trauma patients, who scored the lowest on the GCS at admission, and among them, the highest values were reported by the children with concomitant peripheral lesions.

CONCLUSIONS

The role of S100B in paediatric traumatic brain injury has not been clarified yet, and the interpretation of its increase when the head trauma is associated with other injuries needs the understanding of the physiopathological mechanisms that rule its release in the systemic circulation. The levels of S100B in serum after a brain injury could be related to the mechanical discharge from a destroyed blood-brain barrier, or they could be due to the active expression by the brain, as a part of its involvement in the systemic inflammatory reaction. Early increase of this protein is not a reliable prognostic index of neurological outcome after pediatric traumatic brain injury, since even very elevated values are compatible with a complete neurological recovery.

The cerebroprotective effects of pentoxifylline and aprotinin during cardiopulmonary bypass in dogs

OBJECTIVE

The purpose of this study was to investigate the cerebroprotective effects of pentoxifylline (PNX) and aprotinin in dogs using cardiopulmonary bypass (CPB).

MATERIALS AND METHODS

Eighteen clinically healthy dogs were divided into three groups: Group 1 (control, n = 6), Group 2 (PNX, n = 6), and Group 3 (aprotinin, n = 6). PNX was administered at a dose of 300 mg/day in Group 2 three days before the operation and during the operation. Half a million IU aprotinin were added to the prime solution and 500,000 IU were transfused via a central venous jugular catheter preoperatively in Group 3. Blood samples were taken from the central jugular vein before and after CPB and interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), and S100beta protein were measured. Gliosis was investigated histopathologically in cerebral cortex biopsy samples under light microscopy.

RESULTS

The preoperative results of IL-6, TNF-alpha, and S100beta protein values were found to be significantly higher (p < 0.001) when compared with postoperative values. This significant difference was observed in the same parameters between Groups 1 and 2, and 1 and 3 (p < 0.001). There was no significant difference between Groups 2 and 3. Comparison between pre- and postoperative levels of IL-6 and TNF-alpha for Group 2 and Group 3 revealed statistically significant differences (p < 0.001), whereas S100beta protein levels did not. Histopathological examinations showed significant differences between the control group and PNX and aprotinin, and between aprotinin and PNX groups (p < 0.001).

CONCLUSION

PNX and aprotinin might be useful in order to reduce postoperative cerebral damage in patients undergoing cardiac surgery with CPB.