Comparison of the Effects of General Anesthesia and Combined Spinal-Epidural Anesthesia on Ferroptosis, Humanin and MOTS-c Levels in Renal Transplantation

University of Gaziantep68 enrolled

Overview

Renal transplantation is the most effective renal replacement therapy for patients with end-stage renal disease. Ischemia-reperfusion injury may adversely affect graft function and long-term outcomes. Ferroptosis has recently emerged as a potential mechanism involved in ischemia-reperfusion injury, while the mitochondrial-derived peptides humanin and MOTS-c are thought to exert protective effects against oxidative stress. However, the effects of different anesthetic techniques on these biomarkers in kidney transplant recipients have not been investigated. This prospective controlled study aims to compare the effects of sevoflurane general anesthesia (SGA) and combined spinal-epidural anesthesia (CSEA) on serum ferroptosis markers, humanin, and MOTS-c levels in adult kidney transplant recipients. Blood samples will be obtained perioperatively for biomarker analysis. The primary objective of the study is to evaluate the effects of the anesthetic technique on serum ferroptosis markers, humanin, and MOTS-c levels. Secondary objectives include evaluating early graft function and postoperative outcomes by assessing the incidence of delayed graft function, postoperative serum creatinine levels, requirement for dialysis, urine output, length of hospital stay, and the association of these outcomes with perioperative biomarker levels.

Renal transplantation represents the most effective form of renal replacement therapy for patients with end-stage renal disease; however, ischemia-reperfusion injury remains a major determinant of early graft dysfunction and long-term transplant outcomes. Ferroptosis, an iron-dependent form of regulated cell death characterized by lipid peroxidation, has recently been proposed as an important mechanism contributing to ischemia-reperfusion-related tissue injury. In addition, mitochondrial-derived peptides such as humanin and MOTS-c have been identified as key regulators of cellular stress responses and may exert protective effects against oxidative damage. Despite these emerging findings, the influence of anesthetic technique on ferroptosis-related pathways and mitochondrial protective peptides in kidney transplantation has not yet been fully elucidated. This prospective controlled study is designed to evaluate the effect of anesthetic technique on perioperative biochemical and clinical outcomes in renal transplant recipients. Adult patients undergoing kidney transplantation will receive either sevoflurane-based general anesthesia (SGA) or combined spinal-epidural anesthesia (CSEA). The two anesthetic strategies will be compared in terms of their effects on circulating ferroptosis-related biomarkers, as well as serum levels of humanin and MOTS-c. Peripheral arterial blood samples will be obtained at two standardized points: immediately before anesthesia induction (T1) and immediately prior to extubation (T2). Following collection, blood samples will be centrifuged, and serum aliquots will be stored under appropriate conditions at -80°C until batch analysis. Serum levels of ferroptosis-related biomarkers, humanin, and MOTS-c will be measured using enzyme-linked immunosorbent assay (ELISA) and standard biochemical techniques. The primary objective of the study is to assess the effect of anesthetic technique on perioperative changes in serum ferroptosis-related biomarkers and mitochondrial-derived peptides (humanin and MOTS-c). The secondary objectives are to evaluate early postoperative graft function and clinical recovery parameters, including incidence of delayed graft function, postoperative serum creatinine levels, requirement for dialysis, urine output, and length of hospital stay. In addition, the association between perioperative biomarker levels and clinical outcomes will be analyzed to explore potential predictive relationships. It is anticipated that this study will provide further insight into the relationship between anesthetic technique, ferroptosis pathways, and mitochondrial-mediated cytoprotection in renal transplantation. The results may contribute to improved understanding of perioperative biological responses and support optimization of anesthetic strategies aimed at enhancing graft outcomes.

Interventions

Sevoflurane General AnesthesiaDRUG

Participants will receive standardized sevoflurane general anesthesia according to institutional kidney transplantation protocols. Anesthesia induction will include preoxygenation with 100% oxygen for 3-5 minutes, followed by intravenous propofol (1.5-2.5 mg/kg), fentanyl (1-2 µg/kg), and rocuronium bromide (0.6 mg/kg). Endotracheal intubation will be performed after short mask ventilation using direct laryngoscopy, and correct placement will be confirmed by auscultation. Anesthesia maintenance will be provided with sevoflurane (1.5-2.0% end-tidal) in a 40-50% oxygen/air mixture and remifentanil infusion (0.05-0.2 µg/kg/min). Mechanical ventilation will be set to 6-8 mL/kg tidal volume, PEEP 5 cmH₂O, and end-tidal CO₂ 35-40 mmHg. At the end of surgery, sevoflurane will be discontinued, neuromuscular blockade will be reversed with sugammadex (2-4 mg/kg), and extubation will be performed after recovery. Postoperative analgesia will include subcutaneous morphine (0.1 mg/kg).

Bupivacaine and Morphine for Combined Spinal-Epidural AnesthesiaDRUG

Participants will receive combined spinal-epidural anesthesia under sterile conditions according to institutional protocols. The L3-L4 interspace will be identified, and local anesthesia will be administered with lidocaine (2-3 mL, 2%). A Tuohy needle will be inserted using a midline approach, and the epidural space will be identified using loss-of-resistance technique. Spinal anesthesia will be achieved via intrathecal injection of 2.5 mL of 0.5% hyperbaric bupivacaine after confirmation of cerebrospinal fluid flow. An epidural catheter will then be placed and secured. Sedation will be provided with intravenous midazolam (1-2 mg), and oxygen will be administered via nasal cannula (4 L/min). Intraoperative analgesia will be maintained with epidural 0.25% bupivacaine as needed. At the end of surgery, epidural morphine (3 mg) combined with 0.25% bupivacaine will be administered for postoperative analgesia.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 70 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Patients aged 18-70 years with American Society of Anesthesiologists (ASA) physical status I-III. * Patients scheduled for elective living-donor allogeneic kidney transplantation. * Patients receiving sevoflurane-based general anesthesia as the anesthetic technique. * Patients receiving combined spinal-epidural anesthesia as the anesthetic technique. Exclusion Criteria: * Patients younger than 18 years or older than 70 years. * Patients undergoing deceased-donor kidney transplantation. * Patients receiving total intravenous anesthesia (TIVA). * Patients who decline to participate in the study or are unable to provide informed consent. * Patients with American Society of Anesthesiologists (ASA) physical status IV or V. * Patients with a history of previous organ transplantation. * Patients with known or suspected mitochondrial disorders. * Patients with a history of chronic corticosteroid use. * Patients requiring red blood cell transfusion intraoperatively or within the first 24 postoperative hours. * Patients with a primary warm ischemia time \>5 minutes, secondary warm ischemia time \>30 minutes, or cold ischemia time \>60 minutes.

Outcomes

Primary Outcomes

Serum ferroptosis-related biomarkers (Fe, TFRC1, GPX4, MDA, ACSL4) and mitochondrial-derived peptides (humanin and MOTS-c)

The primary outcome is the perioperative change in serum levels of ferroptosis-related biomarkers and mitochondrial-derived peptides, including humanin and MOTS-c, between two standardized time points. Blood samples will be collected immediately prior to anesthesia induction and immediately prior to extubation. Biomarker levels will be quantified using ELISA-based and standard biochemical methods. The primary comparison will evaluate differences in biomarker changes between the sevoflurane general anesthesia (SGA) and combined spinal-epidural anesthesia (CSEA) groups.

Time frame: Immediately before anesthesia induction and immediately before extubation (intraoperative period)

Secondary Outcomes

Delayed Graft Function (DGF)

Delayed graft function will be defined as the requirement for dialysis within the first 7 postoperative days or a reduction in serum creatinine of less than 30% during the first 48 hours after transplantation. The incidence of delayed graft function will be compared between the study groups.

Time frame: Postoperative days 0-7

Postoperative Serum Creatinine Levels

Serial serum creatinine levels will be measured daily during the first postoperative week to evaluate early renal graft function and recovery.

Time frame: Postoperative days 1-7

Requirement for Postoperative Dialysis

The need for dialysis during the early post-transplant period will be recorded as a clinical indicator of graft dysfunction.

Time frame: Within first 7 postoperative days

Urine Output

Hourly urine output will be monitored to assess immediate graft perfusion and early functional recovery.

Time frame: Intraoperative period and first 24 postoperative hours

Length of Hospital Stay

Total duration of postoperative hospitalization will be recorded as a measure of overall recovery and clinical course.

Time frame: From surgery until discharge (up to 30 days)

Association Between Biomarkers and Clinical Outcomes

Correlation analyses will be performed to evaluate the relationship between perioperative biomarker levels (ferroptosis markers, humanin, and MOTS-c) and early clinical outcomes, including delayed graft function, serum creatinine levels, and urine output.

Time frame: Perioperative period and first 7 postoperative days