Effects of local anesthetics on the respiratory burst of cord blood neutrophils in vitro

Immature neutrophils in cord blood exert increased expression of genes associated with antimicrobial function

Introduction

The immune systems of both the mother and the newborn face significant challenges during birth. Proper immune regulation after birth is essential for the survival of neonates. Numerous studies have demonstrated that the neonatal immune system is relatively immature, particularly in its adaptive arm, placing the primary responsibility for immune surveillance on innate immunity.

Methods

Given the significant role of neutrophils in protecting the neonate after birth, we conducted a study investigating the properties of neutrophils in newborn cord blood using various methodological approaches.

Results

Our findings demonstrate the presence of immature low-density neutrophils in the cord blood, which are likely responsible for the observed elevated expression of genes coding for proteins essential to antimicrobial response, including myeloperoxidase, neutrophils elastase, and defensins.

Discussion

We propose that these cells function normally and support the protection of newborns early after birth. Furthermore, our results suggest that the mode of delivery might significantly influence the programming of neutrophil function. The presented findings emphasize the importance of distinct neutrophil subpopulations in neonatal immunity and their potential impact on early postnatal health.

The effect of local anaesthetics on apoptosis and NETosis of human neutrophils in vitro: comparison between lidocaine and ropivacaine

There are immunological consequences to the method by which neutrophils undergo cell death. Neutrophil apoptosis, called silent death, leads to the resolution of inflammation, while NETosis deepens and prolongs the inflammatory response and is associated with a worse prognosis of severe infections, e.g., sepsis. Besides nociceptive inhibition, local anaesthetics modulate leukocyte functions, even at low, clinically relevant concentrations. There is currently no data on ropivacaine NETosis, and this study aimed to evaluate the impact of clinical concentrations of ropivacaine (0.0007, 0.007 and 1.4 mmol/L) and lidocaine (0.002, 0.02 and 4 mmol/L) on apoptosis and NETosis of adult peripheral blood neutrophils after 2 h of incubation. Neutrophil identification, apoptosis and NETosis were evaluated by flow cytometry using forward and side scatter characteristics and fluorescent labelling: CD15 for neutrophils identification; Annexin V and propidium iodide for apoptosis and citrullinated histone H3 and myeloperoxidase for NETosis. Lidocaine (4 mmol/L) and ropivacaine (1.4 mmol/L) induced early apoptosis in resting but not in stimulated neutrophils. Low doses of ropivacaine (0.0007 and 0.007 mmol/L) decreased the number of late apoptotic neutrophils, and the lowest dose slightly increased their viability. None of the drugs induced NETosis in resting neutrophils but decreased NETosis at clinical concentrations compared to PMA-stimulated 4 mM lidocaine, PMA-stimulated control, and 1.4 mM ropivacaine. The effect of lidocaine and ropivacaine on apoptosis and NETosis depended on neutrophil stimulation and drug concentrations. Ropivacaine tends to be cytoprotective at concentrations observed in plasma under local anaesthesia. Lidocaine enhanced NETosis at high concentration only in stimulated neutrophils. Thus, both drugs have the ability to change the course of inflammation.

Perioperative Intravenous Lidocaine and Metastatic Cancer Recurrence - A Narrative Review

Cancer is a major global health problem and the second leading cause of death worldwide. When detected early, surgery provides a potentially curative intervention for many solid organ tumours. Unfortunately, cancer frequently recurs postoperatively. Evidence from laboratory and retrospective clinical studies suggests that the choice of anaesthetic and analgesic agents used perioperatively may influence the activity of residual cancer cells and thus affect subsequent recurrence risk. The amide local anaesthetic lidocaine has a well-established role in perioperative therapeutics, whether used systemically as an analgesic agent or in the provision of regional anaesthesia. Under laboratory conditions, lidocaine has been shown to inhibit cancer cell behaviour and exerts beneficial effects on components of the inflammatory and immune responses which are known to affect cancer biology. These findings raise the possibility that lidocaine administered perioperatively as a safe and inexpensive intravenous infusion may provide significant benefits in terms of long term cancer outcomes. However, despite the volume of promising laboratory data, robust prospective clinical evidence supporting beneficial anti-cancer effects of perioperative lidocaine treatment is lacking, although trials are planned to address this. This review provides a state of the art summary of the current knowledge base and recent advances regarding perioperative lidocaine therapy, its biological effects and influence on postoperative cancer outcomes.

Viability and intracellular nitric oxide generation in the umbilical cord blood CD34+CD133- and CD34+CD133+ cell populations exposed to local anaesthetics

Local anesthetics (LAs) are capable of influencing cell viability in systemic immunity and may also modify metabolism of those present in umbilical cord blood (UCB) following obstetric neuraxial analgesia and anaesthesia. Data regarding UCB immature cells, important for the neonate and critical for putative UCB transplantations, are lacking. LAs are capable of stimulating intracellular nitric oxide (NO) in human neutrophils; no information is available concerning newly perpetuated cells and its potential association with viability. The study aimed at assessing the LAs influence on the cell viability and intracellular NO production by UCB CD34⁺CD133^– and CD34⁺ CD133⁺ cell populations. Mononuclear cells separated from UCB samples (n = 19) were incubated with bupivacaine (0.0005, 0.005, 1 mM), lidocaine (0.002, 0.02, 4 mM), and ropivacaine (0.0007, 0.007, 1.4 mM) for 4 h. Flow cytometry was applied for the assessment of cell viability and intracellular NO generation in CD34⁺CD133^– and CD34⁺CD133⁺ cell populations using annexinV/7-AAD and DAF-2DA stainings, respectively. CD34⁺CD133⁺ cells showed less pronounced late apoptosis and necrosis as compared to CD34⁺CD133-population. Intracellular NO generation was comparable between both cell populations studied. LAs neither influenced cell viability nor changed NO production in either population. LAs do not interfere with viability and intracellular NO generation in the UCB CD34⁺CD133^– and CD34⁺CD133⁺ cell populations.

Potential Impact of Local Anesthetics Inducing Granulocyte Arrest and Altering Immune Functions on Perioperative Outcome

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.

Leukocyte Coping Capacity: An Integrative Parameter for Wildlife Welfare Within Conservation Interventions

Wildlife management, conservation interventions and wildlife research programs often involve capture, manipulation and transport of wild animals. Widespread empirical evidence across various vertebrate taxa shows that handling wildlife generally induces a severe stress response resulting in increased stress levels. The inability of individuals to appropriately respond to rapidly changing environmental conditions during and after manipulations may have deleterious and long-lasting implications on animal welfare. Therefore, mitigating stress responses in the frame of conservation interventions is a key animal welfare factor. However, we have a poor understanding of the metrics to adequately assess and monitor the dynamic physiological changes that animals undergo when subjected to stressful procedures in wild or captive conditions. A growing number of studies provide good evidence for reciprocal interactions between immune processes and stress. Here, we review the existing literature on a relatively new technique-Leukocyte Coping Capacity (LCC), a proxy for stress quantifying oxygen radical production by leukocytes. We discuss the strength and weaknesses of this immunological approach to evaluate stress, the individual capacity to cope with stress and the resulting potential implications for animal welfare. Additionally we present new data on LCC in captive roe deer (Capreolus capreolus) under long-time anesthesia and free-ranging Asiatic wild asses (Kulan; Equus hemionus kulan) were LCC was used to assess stress levels in animals captured for a reintroduction project.

Local anaesthetics upregulate nitric oxide generation in cord blood and adult human neutrophils

Nitric oxide (NO) generation by systemic neonatal neutrophils is not clarified. It is also not known whether local anaesthetics (LAs) transferred to the fetal systemic circulation following maternal epidural blockade may affect this process. In the present study, NO generation was evaluated in neutrophils from cord blood (CB, n = 11) and adult blood (n = 10) following exposure to bupivacaine (0.0005, 0.005, 1 mM), lidocaine (0.002, 0.02, 4 mM) and ropivacaine (0.0007, 0.007, 1.4 mM) using flow cytometry, as well as indirectly by determining nitrite concentrations in cell incubation media. To determine the role of NO synthase (NOS) isoforms in NO generation following exposure to LAs, experiments were repeated in the presence of the NOS inhibitors, N^G-nitro-L-arginine methyl ester and aminoguanidine; in addition, the expression of NOS isoforms was analysed. CB neutrophils produced less NO than adult neutrophils. LAs, especially ropivacaine and lidocaine, stimulated neutrophil NO generation, but in CB neutrophils this effect was negligible at clinically relevant drug concentrations. A mechanism involving NOS activity was responsible for the observed phenomena. In conclusion, LAs are able to upregulate neutrophil NO production, but in neonates this effect is likely to be clinically insignificant.