Ropivacaine Activates Multiple Proapoptotic and Inflammatory Signaling Pathways That Might Subsume to Trigger Epidural-Related Maternal Fever

Abstract

BACKGROUND: Epidural-related maternal fever (ERMF) is an adverse effect of epidural analgesia during labor and is associated with perinatal and neonatal morbidity. Local anesthetics have been proposed to trigger ERMF via sterile inflammation. Ropivacaine is currently the most frequently used epidural anesthetic and considered least toxic. This study investigates molecular effects of ropivacaine on human umbilical vein endothelial cells (HUVECs) as model system for endothelial cells and human placental trophoblasts (TBs), compares the effects to the putative anti-inflammatory lidocaine and investigates the partially alleviating impact of the anti-inflammatory corticosteroid dexamethasone. METHODS: HUVECs and TBs were exposed to ropivacaine (35 μM–7 mM) or lidocaine (21 mM) with or without dexamethasone (1 μM). AnnexinV/propidium iodide staining and lactate dehydrogenase release were used to analyze apoptosis and cytotoxicity. Proinflammatory interleukins-6 (IL-6) and IL-8 as well as prostaglandin E2 (PGE2) were measured by enzyme-linked immunosorbent assay (ELISA), while activation of signaling pathways was detected by Western blotting. Oxidative stress was visualized by live cell imaging and quantification of antioxidant proteins, intercellular adhesion molecule 1, vascular cell adhesion molecule 1, platelet endothelial cell adhesion molecule 1, cyclooxygenase 2, and mitochondrial deoxyribonucleic acid by real-time polymerase chain reaction. Dissipation of the mitochondrial membrane potential was assessed with cytofluorimetric analysis using the J-Aggregate (JC-1 staining [cytofluorimetric analysis using the J-Aggregate]). RESULTS: Ropivacaine exposure dose-dependently induced apoptosis and an increased release of IL-6, IL-8, and PGE2 from HUVECs and TBs. Furthermore, caspase-3, nuclear factor-κB, and p38 mitogen-activated protein kinase pathways were activated, while extracellular signal–regulated kinase 1/2 and protein kinase B (Akt) were dephosphorylated. Downregulation of antioxidative proteins induced oxidative stress and upregulation of ICAM1, VCAM1, and PECAM1 possibly facilitate leukocyte transmigration. Mitochondrial effects included increased release of the proinflammatory mitochondrial DNA damage–associated molecular patterns, but no significant dissipation of the mitochondrial membrane potential. Conversely, lidocaine exhibited repression of IL-6 and IL-8 release over all time points, and early downregulation of COX2 and cell adhesion molecules, which was followed by a late overshooting reaction. Dexamethasone reduced especially inflammatory effects, but as an inducer of mitophagy, had negative long-term effects on mitochondrial function. CONCLUSIONS: This study suggests that ropivacaine causes cellular injury and death in HUVECs and TBs via different signaling pathways. The detrimental effects induced by ropivacaine are only partially blunted by dexamethasone. This observation strengthens the importance of inflammation in ERMF.

Epidural analgesia, intrapartum hyperthermia, and neonatal brain injury: a systematic review and meta-analysis

“…13 The immunomodulation mechanism is that the local anaesthetic either stimulates the release of interleukin-6, and thus induces activity in the pro-pyrogenic inflammatory pathway or inhibits the release of interleukin-1 receptor antagonist, and thus reduces the activity in the anti-pyrogenic inflammatory pathway, or both. 14,15 Although not a primary focus, this systematic review found no evidence favouring one mechanism.…”

“…However, the proposed immunomodulation mechanism of epidural hyperthermia may link with the cytokine hypothesis. 14,15 The diagnosis of clinical chorioamnionitis requires intrapartum hyperthermia in addition to other clinical signs of infection, such as tachycardia (maternal and fetal), tachypnoea, leucocytosis, and foul-smelling vaginal discharge. 96 However, of these symptoms, only foul-smelling vaginal discharge cannot be attributed to the hyperthermia itself.…”

Association between epidural analgesia and indications for intrapartum caesarean delivery in group 1 of the 10-group classification system at a tertiary maternity hospital, Shanghai, China: a retrospective cohort study

“…While the exact pathophysiological mechanism is not well understood, existing evidence suggests that epidural-related maternal fever may reflect a non-infectious inflammatory process [ 27 ]. A recent lab-based study conducted by Wohlrab et al [ 28 ] showed that ropivacaine may induce the release of IL-6 and IL-8 cytokines and activate multiple proapoptotic and inflammatory signalling pathways (caspase, NFKB, and P38), triggering epidural-related maternal fever. Despite this, EA appeared to have no impact on assisted vaginal delivery rates and the duration of the first and second stages of labour in this study.…”

Current Resources for Evidence‐Based Practice, May/June 2021

“…The one with the strongest evidence is that local anesthetics either release proinflammatory cytokines or inhibit anti‐inflammatory cytokines that affect endothelial, trophoblastic, and white blood cells 10–12 . A recent laboratory study showed a ropivacaine‐induced apoptosis and inflammatory cytokines in umbilical cord tissue 13 . Another theory is that epidural analgesia blocks a sympathetic response, decreasing sweating and hyperventilation and, therefore, lowering ability to dissipate heat.…”