Introduction: Local anesthetics (LAs) are frequently used during anesthesia; however, they may influence granulocyte function which in turn could modify immune responses in the perioperative period. Therefore, the aim of this study was to investigate the impact of clinically used doses of bupivacaine and lidocaine on granulocyte function with regard to migration, reactive oxygen species (ROS) production, neutrophil extracellular traps (NETosis) formation, and viability. Methods: A total of 38 granulocyte-enriched samples from healthy subjects were obtained by whole blood lysis. Polymorphonuclear neutrophil (PMN) samples were incubated simultaneously with different concentrations of either bupivacaine (0.03– 3.16 mmol/L) or lidocaine (0.007– 14.21 mmol/L), or without drug (control). Live cell imaging was conducted in order to observe granulocyte chemotaxis, migration, ROS production, and NETosis. Flow cytometry was used to analyze viability and antigen expression. Results: The track length (TL) of PMNs exposed to bupivacaine concentrations of 0.16 mmol/L and above significantly decreased compared to the control. Low concentrations of lidocaine were associated with slight but significant increases in TL, whereas this changed with concentrations above 1.4 mmol/L, showing a significant decrease in TL. PMN incubated with bupivacaine concentrations of 1.58 mmol/L and above or lidocaine concentrations of at least 3.6 mmol/L showed no migration or chemotaxis at all. Time to onset of maximal ROS production and time for half-maximal NETosis decreased in a dose-dependent manner for both substances. Equipotency in NETosis induction was reached by bupivacaine (1.1 mmol/L) at significantly lower concentrations than lidocaine (7.96 mmol/L). Cell viability and oxidative burst were unaffected by LAs. Conclusion: Local anesthetics in clinically used doses ameliorate granulocyte defense mechanisms, thus indicating their potentially decisive effect during the perioperative period.

Chemotaxis and the formation of suicidal neutrophil extracellular traps (suicidal NETosis) are key functions of polymorphonuclear cells (PMNs). Neutrophil extracellular traps in particular are known to be significantly involved in the severity of inflammatory and immunological disorders such as rheumatoid arthritis and Crohn’s disease. Therefore, detailed knowledge of PMNs is essential for analyzing the mechanisms involved in, and developing new therapies for, such diseases. To date, no standard method to analyze these cell activities has been established. This study used in vitro live cell imaging to simultaneously observe and analyze PMN functions. To demonstrate this, the effects of phorbol‐12‐myristat‐13‐acetat (PMA, 0.1‐10 nM), N‐formylmethionine‐leucyl‐phenylalanine (fMLP, 10 nM), and protein kinase C inhibitor 1‐(5‐isoquinolinesulfonyl)‐2‐methylpiperazine (H7) on PMN chemotaxis and suicidal NETosis were studied. PMA (1 nM‐10 nM) resulted in significant concentration‐dependent behavior in chemotaxis and an earlier onset of maximum oxidative burst and NET formation of up to 44%. When adding H7, PMA‐triggered PMN functions were reduced, demonstrating that all three functions rely mostly on protein kinase C (PKC) activity, while PKC is not essential for fMLP‐induced PMN activity. Thus, the method here described can be used to objectively quantify PMN functions and, especially through the regulation of the PKC pathway, could be useful in further clinical studies of immunological disorders.

Background: Sepsis is a leading cause of morbidity and mortality worldwide. Many patients suffering from sepsis are treated on intensive care units and many of them require mechanical ventilation under sedation or general anesthesia. Propofol, a drug used for these purposes, is known to interact with polymorphonuclear granulocytes (PMNs). Therefore, the aim of this study was to investigate the influence of propofol on PMN functions after experimental Gram-negative induced sepsis using lipopolysaccharide (LPS) stimulation. Methods: A total of 34 granulocyte-enriched samples were collected from healthy subjects. PMNs were isolated by density gradient centrifugation and incubated simultaneously with either 6 μg/mL or 60 μg/mL propofol, or none (control). Additionally, the experimental sepsis samples were incubated with either 40 pg/mL or 400 pg/mL LPS. Live cell imaging was conducted in order to observe granulocyte chemotactic migration, ROS production, and NETosis. Flow cytometry was used to analyze viability and antigen expression. Results: Propofol led to significantly reduced PMN track length (p < 0.001) and track speed (p < 0.014) after LPS-induced sepsis in a dose-dependent manner. NETosis (p = 0.018) and ROS production (p = 0.039) were accelerated by propofol without LPS incubation, indicating improved immune function. Propofol also ameliorated LPS-induced increased NETosis and ROS-production. Antigen expression for CD11b, CD62l and CD66b was unaffected by propofol. Conclusion: Propofol improves LPS-induced exaggerated PMN activation in an ex vivo model. Beneficial effects due to restored immune function in septic patients might be possible, but needs further investigation.

This study examines how different concentrations of arginine vasopressin (AVP) and its preservative chlorobutanol (ClB) impact the immune functions of human polymorphonuclear neutrophils (PMNs), which are crucial in the immune response, particularly in sepsis. Using a model to simulate the physiological, sepsis-related, and therapeutic AVP levels in plasma, we analysed how AVP and ClB affect PMN activities, including reactive oxygen species (ROS) production, NETosis, antigen expression, and migration. PMNs were isolated from whole human blood and assessed using flow cytometry and live cell imaging. The results indicated that neither AVP nor ClB significantly affected PMN viability, antigen expression, NETosis, or ROS production in response to N-Formylmethionine-leucyl-phenylalanine, or fMLP, and tumour necrosis factor alpha. In the migration assays, concentration-dependent effects were observed. At physiological AVP levels, PMN migration showed no reduction, while the sepsis-associated AVP levels initially reduced migration before returning to the baseline or even increasing. The therapeutic AVP concentrations showed similar migration to that in the controls, while high concentrations progressively inhibited migration. ClB, regardless of its concentration, enhanced PMN migration. These findings suggest that AVP during sepsis may impair PMN migration, potentially contributing to tissue damage and systemic complications. This highlights AVP’s role as a possible immune modulator in complex immune responses.