<p><strong>Aim.</strong> The study was designed to evaluate the efficacy of polypeptide neuroprotection using brain protein “Cellex” for prevention of postoperative cognitive dysfunction after cardiac surgery.<br /><strong>Methods.</strong> Our study included 60 patients undergoing elective cardiosurgical operations, who were randomized into two groups. In the “Cellex” group, the patients received 1.0 ml of “Cellex” subcutaneously daily during 8 days, beginning from the preoperative day, while the control group patients were given a saline placebo. The cognitive function was assessed using a Montreal cognitive assessment (MoCA) test on the day before surgery and also at Days 3 and 7 postoperatively. The plasma concentrations of S100b protein were measured before surgery, and at Days 3 and 7. The patients’ gas exchange, hemodynamics and cerebral oxygenation were monitored. In addition, the efficacy of “Cellex” and the severity of cognitive dysfunction were evaluated intraoperatively under cardiopulmonary bypass.<br />Results. The duration of intervention and mechanical ventilation, as well as hemodynamics and cerebral oximetry data did not differ significantly between the groups. There was a transient decline of cognitive functions and an increase in plasma concentration of S100b at Day 3 after surgery in both groups (p<0.05). At Day 7, the MoCA score was still decreased in the control group (p<0.003), but returned to the baseline in the “Cellex” group. These effects became more pronounced after cardiopulmonary bypass. The intraoperative PaCO2 correlated with cerebral oxygenation surgery by the beginning and at the end of surgery (rho = 0.305, p = 0.033 and rho = 0.533; p<0.001). <br />Conclusion. The perioperative use of “Cellex” can attenuate cognitive dysfunction after cardiac surgery, especially when following interventions under cardiopulmonary bypass.</p><p>Received 25 May 2017. Revised 9 November 2017. Accepted 13 November 2017.</p><p><strong>Funding:</strong> The study was carried out with support of the “Farm-Sintez” company’s grant. The money was spent for purchase of the preparation, the authors’ honoraria and purchase of a kit for determining S100b protein concentration. The sponsors’ support had no impact on the study design and data acquisition, analysis and interpretation. The “Farm-Sintez” company’s representatives were not participating in the preparation and publication of the article.</p><p><strong>Conflict of interest:</strong> The study was carried out with support of the “Farm-Sintez” company’s grant.</p><p><strong>Author contributions</strong><br />Conception and study design: M.A. Putanov, M.M. Sokolova, P.I. Lenkin, M.Yu. Kirov <br />Data collection and analysis: M.A. Putanov, M.M. Sokolova, P.I. Lenkin, I.G. Baskakova, A.N. Kiriluk, D.N. Kazarinov, K.M. Checkaya, T.S. Isakova, M.A. Rumyanceva, V.Yu. Slastilin <br />Statistical data analysis: M.M. Sokolova <br />Drafting the article: M.A. Putanov, M.M. Sokolova <br />Critical revision of the article: M.Yu. Kirov <br />Final approval of the version to be published: M.A. Putanov, M.M. Sokolova, P.I. Lenkin, V.Yu. Slastilin, I.G. Baskakova, A.N. Kiriluk, D.N. Kazarinov, K.M. Checkaya, T.S. Isakova, M.A. Rumyanceva, M.Yu. Kirov</p>
