Endothelial Dysfunction in Patients Undergoing Cardiac Surgery: A Narrative Review and Clinical Implications.

Cardiac surgery is one of the highest-risk procedures, usually involving cardiopulmonary bypass and commonly inducing endothelial injury that contributes to the development of perioperative and postoperative organ dysfunction. Substantial scientific efforts are being made to unravel the complex interaction of biomolecules involved in endothelial dysfunction to find new therapeutic targets and biomarkers and to develop therapeutic strategies to protect and restore the endothelium. This review highlights the current state-of-the-art knowledge on the structure and function of the endothelial glycocalyx and mechanisms of endothelial glycocalyx shedding in cardiac surgery. Particular emphasis is placed on potential strategies to protect and restore the endothelial glycocalyx in cardiac surgery. In addition, we have summarized and elaborated the latest evidence on conventional and potential biomarkers of endothelial dysfunction to provide a comprehensive synthesis of crucial mechanisms of endothelial dysfunction in patients undergoing cardiac surgery, and to highlight their clinical implications.

Decrease of Perforin Expressing Lymphocytes after On-Pump Coronary Artery Bypass Grafting Surgery Irrespective of Carbohydrate Preoperative Oral Feeding.

BACKGROUND: Coronary artery bypass grafting (CABG) surgery continues to be the gold standard for treating the patients with coronary artery disease. CABG surgery can be performed on or off cardiopulmonary bypass, termed as on-pump or off-pump CABG, respectively. It has been shown that CABG surgery, preferably on-pump CABG surgery, leads to the changes of cell immunity during perioperative and early postoperative period. The mechanisms of regulation of the immune response in patients during and early after surgical revascularization are not fully understood. The aim of this study was to investigate the influence of carbohydrate preoperative oral feeding on frequency and perforin expression in peripheral blood lymphocytes in patients after on- or off-pump CABG surgery in early postoperative period. PATIENTS AND METHODS: In this prospective clinical study, 80 patients scheduled for CABG surgery were included in the study. The patients were randomly allocated into four groups (20 in each group): patients in Group 1 underwent on-pump CABG and did not receive carbohydrate preoperative oral feeding; patients in Group 2 underwent on-pump CABG and were preoperatively fed; patients in Group 3 underwent off-pump CABG and did not receive carbohydrate preoperative oral feeding; while patients in Group 4 underwent off-pump CABG and received carbohydrate preoperative oral feeding. Blood samples were collected immediately before (T1), 24 (T2) and 72 (T3) hours after the surgery. Peripheral blood mononuclear cells were isolated by gradient centrifugation and simultaneously labelled by antigens using fluorochrome-conjugated monoclonal antibodies. Frequency of T lymphocytes, NK and NKT cells, their subsets as well as their perforin expression were detected, and analyzed by flow cytometry. RESULTS: There was significant decrease in frequency of CD3+ and CD3+CD4+ cells, as well as perforin expressing CD3+CD8+ cells in patients who underwent on-pump CABG in comparison to patients who underwent off-pump CABG 24 hours after the surgery. Carbohydrate preoperative oral feeding did not effect changes in lymphocytes subpopulations and perforin expression at any time point. CONCLUSION: Decreases of CD3+ cells on account of CD3+CD4+ subsets, and perforin expressing cells on account of CD3+CD8+ perforin+ cells were found in patients who had undergone on-pump CABG, but not in patients who had undergone off-pump CABG surgery, irrespectively of carbohydrate preoperative oral feeding.

Frequency and perforin expression of different lymphocyte subpopulations in patients with lower limb fracture and thoracic injury.

INTRODUCTION: Trauma with multiple injuries is associated with a high risk of complications, which may be related to excessive stimulation of inflammatory and anti-inflammatory responses. Although the effects of polytrauma on the immune response have been well established at the cellular and molecular levels, there is little information about the changes in the cytolytic potential of immunocompetent cells, including expression of cytotoxic molecules such as perforin. Therefore, the objective of the present study was to analyse and compare differences in the frequency and perforin expression of leukocyte subpopulations in the peripheral blood of patients with lower limb fracture, thoracic injury, and simultaneous lower limb fracture and thoracic injury. PATIENTS AND METHODS: Forty-five patients with trauma injury (15 patients with lower limb injury, 15 patients with thoracic injury, and 15 patients with simultaneous lower limb and thoracic injury) were included in the study. Peripheral blood of 15 sex- and age-matched healthy volunteers served as the control group. Peripheral blood samples were taken from all subjects included in the study and peripheral blood mononuclear cells were isolated by gradient centrifugation. The frequency of T lymphocytes, natural killer (NK) and NK T cells, and their subsets, as well as their perforin expression levels were simultaneously detected and analysed by flow cytometry. RESULTS: There was a statistically significant decrease in the frequency of T lymphocytes, NK and NK T cells as well as perforin expression in the patients with simultaneous lower limb and thoracic injury compared with the other two groups, with a predominantly marked decrease in NK and NK T cells. CONCLUSION: The decrease in the frequency and cytotoxic potential of peripheral blood lymphocytes is related to the severity of trauma injury, which can explain the underlying mechanism contributing to complication occurrence.

Endothelial dysfunction mediated by interleukin-18 in patients with ischemic heart disease undergoing coronary artery bypass grafting surgery.

When medication management or percutaneous coronary intervention is not successful in patients with advanced ischemic heart disease, surgical revascularisation-predominantly coronary artery bypass grafting (CABG)-is considered the gold standard. However, CABG surgery can lead to ischemia/reperfusion injury, which is characterized by a strong inflammatory response. Interleukin (IL)-18, is a strong inflammatory mediator, that is released from cardiomyocytes and can be found in the systemic circulation of patients during and immediately after CABG surgery. The existing damage of endothelial glycocalyx in patients with ischemic heart disease is further impaired concurrently during the surgery due to the anaesthesia-surgical technique used and intravascular fluid loading. This results in the increased incidence of adverse events, including myocardial infarction. IL-18 leads to the activation of lymphocyte cytotoxicity via cytotoxic mediators (Fas ligand, Tumour necrosis factor (TNF)-related apoptosis-inducing ligand, perforin, and granulysin). We hypothesize that IL-18 is released locally in the heart and the systemic circulation in patients undergoing CABG surgery and may be correlated with the level of activity of circulating lymphocytes. In turn, this may lead to lymphocyte-mediated cytotoxicity directed toward damaged and activated endothelial cells. Shear stress glycocalyx, as well as damaged and activated endothelial cells then become the main the source of pro-inflammatory cytokines, chemokines, and adhesion molecules. These attract activated lymphocytes to adhere to the endothelium or enter the subintimal layer, increasing existing or initiating the formation of new plaques, which leads to the development of myocardial infarction during or shortly after surgery. To evaluate our hypothesis, we will measure the local concentration of IL-18 in the sinus coronarius and systemic circulation. These values will then be correlated with immunological and biochemical parameters, predominantly with the concentration of degradation products of glycocalyx and cytotoxic mediators in activated lymphocytes. If our hypothesis is correct, measuring the IL-18 concentration that is responsible for glycocalyx deterioration, may become a useful tool for predicting myocardial infarction occurrence in patients undergoing CABG surgery.

Pharmacological effects of primaquine ureas and semicarbazides on the central nervous system in mice and antimalarial activity in vitro.

New primaquine (PQ) urea and semicarbazide derivatives 1-4 were screened for the first time for central nervous system (CNS) and antimalarial activity. Behavioural tests were performed on mice. In vitro cytotoxicity on L-6 cells and activity against erythrocytic stages of Plasmodium falciparum was determined. Compound 4 inhibited 'head-twitch' responses and decreased body temperature of mice, which suggests some involvement of the serotonergic system. Compound 4 protected mice against clonic seizures and was superior in the antimalarial test. A hybrid of two PQ urea 2 showed a strong antimalarial activity, confirming the previous findings of the high activity of bis(8-aminoquinolines) and other bisantimalarial drugs. All the compounds decreased the locomotor activity of mice, what suggests their weak depressive effects on the CNS, while PQ derivatives 1 and 2 increased amphetamine-induced hyperactivity. None of the compounds impaired coordination, what suggests a lack of their neurotoxicity. All the tested compounds presented an antinociceptive activity in the 'writhing' test. Compounds 3 and 4 were active in nociceptive tests, and those effects were reversed by naloxone. Compound 4 could be a useful lead compound in the development of CNS active agents and antimalarials, whereas compound 3 may be considered as the most promising lead for new antinociceptive agents.