Therapeutic gene delivery by mesenchymal stem cell for brain ischemia damage: Focus on molecular mechanisms in ischemic stroke.

Cerebral ischemic damage is prevalent and the second highest cause of death globally across patient populations; it is as a substantial reason of morbidity and mortality. Mesenchymal stromal cells (MSCs) have garnered significant interest as a potential treatment for cerebral ischemic damage, as shown in ischemic stroke, because of their potent intrinsic features, which include self-regeneration, immunomodulation, and multi-potency. Additionally, MSCs are easily obtained, isolated, and cultured. Despite this, there are a number of obstacles that hinder the effectiveness of MSC-based treatment, such as adverse microenvironmental conditions both in vivo and in vitro. To overcome these obstacles, the naïve MSC has undergone a number of modification processes to enhance its innate therapeutic qualities. Genetic modification and preconditioning modification (with medications, growth factors, and other substances) are the two main categories into which these modification techniques can be separated. This field has advanced significantly and is still attracting attention and innovation. We examine these cutting-edge methods for preserving and even improving the natural biological functions and therapeutic potential of MSCs in relation to adhesion, migration, homing to the target site, survival, and delayed premature senescence. We address the use of genetically altered MSC in stroke-induced damage. Future strategies for improving the therapeutic result and addressing the difficulties associated with MSC modification are also discussed.

Effects of remote ischemic preconditioning in hepatectomy: a systematic review and meta-analysis.

BACKGROUND: Animal experiments have confirmed that remote ischemic preconditioning (RIPC) can reduce hepatic ischemia-reperfusion injuries (HIRIs), significantly improving early tissue perfusion and oxygenation of the residual liver after resections, accelerating surgical prognoses, and improving survival rates. However, there is still controversy over the role of RIPC in relieving HIRI in clinical studies, which warrants clarification. This study aimed to evaluate the beneficial effects and applicability of RIPC in hepatectomy and to provide evidence-based information for clinical decision-making. METHODS: Randomized controlled trials (RCTs) evaluating the efficacy and safety of RIPC interventions were collected, comparing RIPC to no preconditioning in patients undergoing hepatectomies. This search spanned from database inception to January 2024. Data were extracted independently by two researchers according to the PRISMA guidelines. The primary outcomes assessed were postoperative alanine transaminase (ALT), aspartate transaminase (AST), total bilirubin (TBIL), and albumin (ALB) levels. The secondary outcomes assessed included duration of surgery and Pringle, length of postoperative hospital stay, intraoperative blood loss and transfusion, indocyanine green (ICG) clearance, hepatocyte apoptosis index, postoperative complications, and others. RESULTS: Ten RCTs were included in this meta-analysis, with a total of 865 patients (428 in the RIPC group and 437 in the control group). ALT levels in the RIPC group were lower than those in the control group on postoperative day (POD) 1 (WMD = - 59.24, 95% CI: - 115.04 to - 3.45; P = 0.04) and POD 3 (WMD = - 27.47, 95% CI: - 52.26 to - 2.68; P = 0.03). However, heterogeneities were significant (I2 = 89% and I2 = 78%), and ALT levels on POD 3 were unstable based on a sensitivity analysis. AST levels on POD 1 in the RIPC group were lower than those in the control group (WMD = - 50.03, 95% CI: - 94.35 to - 5.71; P = 0.03), but heterogeneity was also significant (I2 = 81%). A subgroup analysis showed no significant differences in ALT and AST levels on POD 1 between groups, regardless of whether the Pringle maneuver or propofol was used for anesthesia (induction only or induction and maintenance, P > 0.05). The remaining outcome indicators were not statistically significant or could not be analyzed due to lack of sufficient data. CONCLUSION: RIPC has some short-term liver protective effects on HIRIs during hepatectomies. However, there is still insufficient evidence to encourage its routine use to improve clinical outcomes. TRIAL REGISTRATION: The protocol of this study was registered with PROSPERO (CRD42022333383).

Effect of Remote Ischemic Conditioning in Ischemic Stroke Subtypes: A Post Hoc Subgroup Analysis From the RESIST Trial.

BACKGROUND: Remote ischemic conditioning (RIC) is a simple and noninvasive procedure that has proved to be safe and feasible in numerous smaller clinical trials. Mixed results have been found in recent large randomized controlled trials. This is a post hoc subgroup analysis of the RESIST trial (Remote Ischemic Conditioning in Patients With Acute Stroke), investigating the effect of RIC in different acute ischemic stroke etiologies, and whether an effect was modified by treatment adherence. METHODS: Eligible patients were adults (aged ≥18 years), independent in activities of daily living, who had prehospital stroke symptoms with a duration of less than 4 hours. They were randomized to RIC or sham. The RIC treatment protocol consisted of 5 cycles with 5 minutes of cuff inflation alternating with 5 minutes with a deflated cuff. Acceptable treatment adherence was defined as when at least 80% of planned RIC cycles were received. The analysis was performed using the entire range (shift analysis) of the modified Rankin Scale (ordinal logistic regression). RESULTS: A total of 698 had acute ischemic stroke, 253 (36%) were women, and the median (interquartile range) age was 73 (63-80) years. Median (interquartile range) overall adherence to RIC/sham was 91% (68%-100%). In patients with a stroke due to cerebral small vessel disease, who were adherent to treatment, RIC was associated with improved functional outcome, and the odds ratio for a shift to a lower score on the modified Rankin Scale was 2.54 (1.03-6.25); P=0.042. The association remained significant after adjusting for potential confounders. No significant associations were found with other stroke etiologies, and the overall test for interaction was not statistically significant (χ2, 4.33, P=0.23). CONCLUSIONS: In patients with acute ischemic stroke due to cerebral small vessel disease, who maintained good treatment adherence, RIC was associated with improved functional outcomes at 90 days. These results should only serve as a hypothesis-generating for future trials. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifier: NCT03481777.

Remote ischemic preconditioning for reduction of ischemia-reperfusion injury after hepatectomy: A randomized sham-controlled trial.

BACKGROUND: Remote ischemic preconditioning reduces ischemia-reperfusion injury in patients undergoing hepatectomy. Moreover, there is evidence that the protective effects of remote ischemic preconditioning may be more pronounced in pre-damaged livers. The objective of this trial was to investigate the extent to which remote ischemic preconditioning can attenuate ischemia-reperfusion injury after hepatectomy and Pringle maneuver in patients with chronic liver disease. METHODS: In this randomized, controlled, triple-blind monocenter trial, a total of 102 patients with chronic liver disease and planned hepatectomy were enrolled between December 2019 and March 2022. Eligible patients were randomized to the remote ischemic preconditioning or sham arms. Remote ischemic preconditioning was induced through 3 10-minute cycles of alternating ischemia and reperfusion of the upper extremity. The study was prospectively registered in the German Clinical Trials Registry (DRKS00018931). RESULTS: A total of 102 patients were included in the study and were randomized (51 per arm). The median age was 69.5 years, approximately two-thirds of the patients were male (69/102, 67.7%), and the mean body mass index was 25.6 kg/m2. Most patients were classified as American Society of Anesthesiologists II (55/102, 53.9%) or III (45/102, 44.1%). The primary endpoint, the transaminases on the first postoperative day (alanine aminotransferase /aspartate aminotransferase: remote ischemic preconditioning arm: 250 (35-1721)/320 (42-1525) U/L versus sham control arm: 283 (32-792)/356 (20-1851) U/L, P = .820/0.639), clinical outcomes as well as remote ischemic preconditioning biomarker levels were comparable between both arms. CONCLUSION: Remote ischemic preconditioning did not achieve a significant reduction in postoperative transaminase levels, nor did it affect clinical results and biomarkers.

Short-term Outcomes of Different Techniques for Gastric Ischemic Preconditioning Before Esophagectomy: A Network Meta-analysis.

BACKGROUND: Ischemia at the anastomotic site plays a critical role determinant in the development of anastomosis-related complications after esophagectomy. Gastric ischemic conditioning (GIC) before esophagectomy has been described to improve the vascular perfusion at the tip of the gastric conduit with a potential effect on anastomotic leak (AL) and stenosis (AS) risk minimization. Laparoscopic (LapGIC) and angioembolization (AngioGIC) techniques have been reported. PURPOSE: Compare short-term outcomes among different GIC techniques. MATERIALS AND METHODS: Systematic review and network meta-analysis. One-step esophagectomy (noGIC), LapGIC, and AngioGIC were compared. Primary outcomes were AL, AS, and gastric conduit necrosis (GCN). Risk ratio (RR) and weighted mean difference (WMD) were used as pooled effect size measures, whereas 95% credible intervals (CrIs) were used to assess relative inference. RESULTS: Overall, 1760 patients (14 studies) were included. Of those, 1028 patients (58.4%) underwent noGIC, 593 (33.6%) LapGIC, and 139 (8%) AngioGIC. AL was reduced for LapGIC versus noGIC (RR=0.68; 95% CrI 0.47-0.98) and AngioGIC versus noGIC (RR=0.52; 95% CrI 0.31-0.93). Similarly, AS was reduced for LapGIC versus noGIC (RR=0.32; 95% CrI 0.12-0.68) and AngioGIC versus noGIC (RR=1.30; 95% CrI 0.65-2.46). The indirect comparison, assessed with the network methodology, did not show any differences for LapGIC versus AngioGIC in terms of postoperative AL and AS risk. No differences were found for GCN, pulmonary complications, overall complications, hospital length of stay, and 30-day mortality among different treatments. CONCLUSIONS: Compared to noGIC, both LapGIC and AngioGIC before esophagectomy seem equivalent and associated with a reduced risk for postoperative AL and AS.

Estudio prospectivo aleatorizado sobre el impacto del preacondicionamiento isquémico remoto sobre la nefropatía por contraste en pacientes intervenidos de reparación aórtica endovascular / Prospective randomized study on the impact of remote ischemic preconditioning on contrast induced nephropathy in endovascular aortic repair patients

Introducción: el mayor inconveniente del uso de contrastes yodados en la práctica clínica es la nefropatía por contraste, que aumenta la morbimortalidad y los costes hospitalarios. El preacondicionamiento isquémico remoto (PCIR) es una técnica de protección tisular no invasiva que ha demostrado ser capaz de disminuir la afectación renal tras la administración de contraste intravascular. Objetivo: el objetivo principal del estudio es valorar el impacto del PCIR en la incidencia de la nefropatía inducida por contraste en pacientes intervenidos de reparación aórtica endovascular (EVAR). Material y métodos: se incluyeron pacientes intervenidos de EVAR electivo asignados de manera secuencial en grupo control y de preacondicionamiento (C y P, respectivamente). Se analizaron parámetros bioquímicos pre- y posoperatorios (a las 24 y a las 72 horas y a los 30 días). Resultados: el 98,3 % de los pacientes incluidos en el estudio fueron varones, sobre una muestra total de 120 pacientes. La media de edad fue de 73 años (rango: 56-87). La diabetes y la insuficiencia renal crónica preoperatoria (entendida como filtrado glomerular < 60 ml/min) estuvieron presentes en el 29,16 % y en el 38,33 % de los pacientes, respectivamente. La mitad de la muestra recibió preacondicionamiento en el preoperatorio. Un total de 24,17 % pacientes desarrollaron nefropatía a pesar de sueroterapia con o sin preacondicionamiento. En el posoperatorio (24-72 h) el preacondicionamiento no modificó la incidencia de nefropatía, creatinina y urea sérica o tasa de filtrado glomerular (eFG). Sin embargo, a los 30 días el grupo preacondicionado mostró una mejoría significativa de las cifras de creatinina y de ureas séricas (1,46 ± 0,3 frente a 1,03 ± 0,5; p < 0,001; 61,06 ± 27,5 mg/dl frente a 43,78 ± 12,9 mg/dl; p = 0,003) y aumento de eFG (56,37 ± 23,4 ml/min /1,73 m2 frente a 72,85 ± 17,7ml/min/ 1,73 m2; p = 0,004)...(AU)

Introduction: the biggest drawback of using iodinated contrasts in clinical practice is contrast nephropathy, which increases morbidity and mortality and hospital costs. Remote ischemic preconditioning (RIPC) is a non-invasive tissue protection technique that has proven to be able to reduce renal involvement after intravascular contrast administration. Objective: the main goal of this study was to assess the impact of RIPC on the incidence of contrast-inducednephropathy in patients undergoing endovascular aortic repair (EVAR).Material and methods: patients who underwent elective EVAR were included, and then sequentially assigned to the control and preconditioning groups (groups C and p, respectively). Pre- and postoperative hematocrit (at 24, 72 hours, and 30 days) was analyzed. Results: total of 98.3 % of the patients included in the study were men out of a total sample of 120 patients. The mean age was 73 years (range, 56-87). Diabetes and preoperative chronic kidney disease (understood as glomerular filtration rates < 60 mL/min) were present in 29.16 % and 38.33 % of the patients, respectively. Half of the sample received preconditioning in the preoperative period. A total of 24.17 % of the patients developed nephropathy despite fluid therapy with or without preconditioning. At the postoperative period (24 h-72 h), preconditioning did not modify the incidence rate of nephropathy, serum creatinine and urea, or even the estimated glomerular filtration rate (eGFR). However, at the 30-day follow-up the preconditioned group showed a significant improvement in serum creatinine and urea levels (1.46 ± 0.3 vs 1.03 ± 0.5; p < 0.001; 61.06 ± 27.5 mg/dL vs 43 .78 ± 12.9 mg/dL; p = 0.003) and eGFR increase (56.37 ± 23.4 mL/min/1.73 m2 vs 72.85 ± 17.7mL/min/1.73 m2; p = 0.004).Conclusions: RIPC seems effective in alleviating the effects of iodinated contrast on the kidneys of patients...(AU)

Effect of Remote Ischemic Preconditioning in Total Knee Arthroplasty on Thiol-Disulfi de Balance: a Randomized Controlled Study.

PURPOSE OF THE STUDY The purpose of this study was to minimize tourniquet-induced ischemia-reperfusion injury (IRI) in total knee arthroplasty (TKA) surgery using the remote ischemic preconditioning (RIPC) model, as well as to assess antioxidant balance with thioldisulfi de homeostasis (TDH). The secondary goal is to evaluate the impact of RIPC on TKA clinical outcomes. MATERIAL AND METHODS Patients in the ASA I-III group who underwent elective TKA were enrolled in this prospective, randomized, double-blind clinical research. TDH parameters were measured individually in groups with (Group I) and without (Group K) RIPC at the following times: preoperative (T0), right before the pneumatic tourniquet was opened (T1), 1 (T2), 6 (T3), and 24 (T4) hours after it was opened. In addition, at 3-hour intervals, the postoperative pain level was assessed using a visual analog scale (VAS). RESULTS This study included 60 cases (Group K; n=30, Group I; n=30). Both groups had equal native thiol, total thiol, disulfi de levels, disulfi de/native thiol, disulfi de/total thiol, and native thiol/total thiol ratios (p>0.05 for each). The change in native thiol, total thiol, and disulfi de values at T0 and T4 periods, however, was not statistically signifi cant for Group K (p=0.049, p=0.047, p=0.037, and p=0.217, p=0.191, p=0.220, respectively). At the 15th hour, VAS values in group I were considerably lower than in Group K (p=0.002). DISCUSSION This prospective, randomized, controlled trial examined how RIPC affected tourniquet-induced IRI-induced oxidative stress in TKA surgery. Lower native, total, and disulfi de levels at each postoperative time point were signifi cant. RIPC may reduce tourniquet-induced IRI-induced oxidative stress and TDH in TKA surgery. RIPC also reduced postoperative discomfort. CONCLUSIONS Our fi ndings suggest that RIPC may protect against the oxidative stress caused by IRI during limb surgery with a tourniquet and improve postoperative clinical outcomes. Key words: remote ischemic preconditioning, ischemia-reperfusion injury, thiol-disulfi de balance, oxidative stress, total knee arthroplasty.

Effect of remote ischemic preconditioning on lung function after surgery under general anesthesia: a systematic review and meta-analysis.

Remote ischemic preconditioning (RIPC) protects organs from ischemia-reperfusion injury. Recent trials showed that RIPC improved gas exchange in patients undergoing lung or cardiac surgery. We performed a systematic search to identify randomized controlled trials involving RIPC in surgery under general anesthesia. The primary outcome was the PaO2/FIO2 (P/F) ratio at 24 h after surgery. Secondary outcomes were A-a DO2, the respiratory index, duration of postoperative mechanical ventilation (MV), incidence of acute respiratory distress syndrome (ARDS), and serum cytokine levels. The analyses included 71 trials comprising 7854 patients. Patients with RIPC showed higher P/F ratio than controls (mean difference [MD] 36.6, 95% confidence interval (CI) 12.8 to 60.4, I2 = 69%). The cause of heterogeneity was not identified by the subgroup analysis. Similarly, A-a DO2 (MD 15.2, 95% CI - 29.7 to - 0.6, I2 = 87%) and respiratory index (MD - 0.17, 95% CI - 0.34 to - 0.01, I2 = 94%) were lower in the RIPC group. Additionally, the RIPC group was weaned from MV earlier (MD - 0.9 h, 95% CI - 1.4 to - 0.4, I2 = 78%). Furthermore, the incidence of ARDS was lower in the RIPC group (relative risk 0.73, 95% CI 0.60 to 0.89, I2 = 0%). Serum TNFα was lower in the RIPC group (SMD - 0.6, 95%CI - 1.0 to - 0.3 I2 = 87%). No significant difference was observed in interleukin-6, 8 and 10. Our meta-analysis suggested that RIPC improved oxygenation after surgery under general anesthesia.Clinical trial number: This study protocol was registered in the University Hospital Medical Information Network (registration number: UMIN000030918), https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000035305.

Laparoscopic ischemic conditioning of the stomach prior to esophagectomy induces gastric neo-angiogenesis.

BACKGROUND: The risk of an anastomotic leakage (AL) following Ivor-Lewis esophagectomy is increased in patients with calcifications of the aorta or a stenosis of the celiac trunc. Ischemic conditioning (ISCON) of the gastric conduit prior to esophagectomy is supposed to improve gastric vascularization at the anastomotic site. The prospective ISCON trial was conducted to proof the safety and feasibility of this strategy with partial gastric devascularization 14 days before esophagectomy in esophageal cancer patients with a compromised vascular status. This work reports the results from a translational project of the ISCON trial aimed to investigate variables of neo-angiogenesis. METHODS: Twenty esophageal cancer patients scheduled for esophagectomy were included in the ISCON trial. Serum samples (n = 11) were collected for measurement of biomarkers and biopsies (n = 12) of the gastric fundus were taken before and after ISCON of the gastric conduit. Serum samples were analyzed including 62 different cytokines. Vascularization of the gastric mucosa was assessed on paraffin-embedded sections stained against CD34 to detect the degree of microvascular density and vessel size. RESULTS: Between November 2019 and January 2022 patients were included in the ISCON Trial. While serum samples showed no differences regarding cytokine levels before and after ISCON biopsies of the gastric mucosa demonstrated a significant increase in microvascular density after ISCON as compared to the corresponding gastric sample before the intervention. CONCLUSION: The data prove that ISCON of the gastric conduit as esophageal substitute induces significant neo-angiogenesis in the gastric fundus which is considered as surrogate of an improved vascularization at the anastomotic site.

PREVENTION OF PATHOLOGICAL EFFECT OF ISCHEMIA-REPERFUSION IN LIVER RESECTION BY SEVOFLURANE PRECONDITIONING.

BACKGROUND: The intermittent Pringle maneuver remains the major technique for controlling hemorrhage during liver surgery. Nevertheless, this procedure involves a risk of triggering a cascade of pathological changes resulting in the ischemia-reperfusion injury (I/R) effect. The pharmacological prevention of this I/R injury represents a promising approach. The aim of the study was to compare the effects of pharmacological preconditioning with sevoflurane and propofol-based intravenous anesthesia on the postoperative function of the liver as the primary end-point. MATERIALS AND METHODS: A prospective cohort study includes the analysis of the data of 73 patients who underwent liver surgery. In the study group (n = 41), preconditioning with sevoflurane inhalation was provided 30 minutes prior to liver resection. In the control group (n = 32), sevoflurane preconditioning was not provided. The primary endpoints were blood lactate concentration shortly after the surgery and one day later; alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities on postoperative Days 1, 3, and 5 as markers of hepatocyte damage. RESULTS: On postoperative Day 1, in patients of the study group, lactate decreased to preoperative levels, while in the control group, lactate content increased as compared to both preoperative levels and the levels immediately after liver resection. A significant difference in AST activity levels between the groups was registered on Day 5, although this difference was not clinically relevant. The decrease in the prothrombin index in the study group on Day 3 was superior to that in the control group. The multiple regression analysis demonstrated a moderate positive association between the number of resected liver segments and the markers of the functional state of the liver in the study group while in the control group, such association was not significant. CONCLUSION: The protective effect of sevoflurane on the postoperative function of the liver is manifested by the lower level of blood lactate and the stable level of transaminase activity.

Remote ischaemic preconditioning increase tolerance to experimentally induced cold pain.

Ischaemic preconditioning (IPC) applied locally and remotely has been shown to reduce pain which may underpin its ergogenic effect on exercise performance, however, it is unclear how many IPC cycles are needed to induce hypoalgesia. Therefore the purpose of this study was to examine the number of cycles of IPC on experimental pain perception. Sixteen healthy participants underwent four, randomised, experimental sessions where they either underwent a sham protocol (1 × 5 min at 20 mmHg), and 1, 2 or 3 cycles × 5 min of remote IPC at 105% of limb occlusion pressure. Ten minutes post-intervention, participants underwent a cold-pressor test where pain threshold, pain tolerance and pain intensity were examined and compared between conditions with a one-way repeated measure analysis of variance. Pain threshold was not different between conditions (P = 0.065); but pain tolerance was increased by ∼30% in the 1 × 5 condition, 2 × 5 condition, and 3 × 5 condition compared to the sham condition. No differences in pain tolerance were seen between the different numbers of cycles (all P > 0.05). There was also no difference in the perception of pain 30 s into the cold pressor test (P = 0.279). Remote IPC appears to significantly improve tolerance to pain which may have significant implications for endurance performance and exercise rehabilitation, but this warrants further investigation.

We found that one, two or three cycles of ischaemic preconditioning improved cold pain tolerance by 30% compared to a sham protocol, but there was no clear effect of IPC on pain threshold or pain intensity.The pain reported during IPC decreased from cycle one to cycle three in the three cycle condition, suggesting a potential conditioned pain modulation effect.An increase in pain tolerance may explain why IPC can improve exercise performance and IPC itself could be used as a tool to improve tolerance to pain.

Ischemic Preconditioning, But Not Priming Exercise, Improves Exercise Performance in Trained Rock Climbers.

ABSTRACT: MacDougall, KB, McClean, ZJ, MacIntosh, BR, Fletcher, JR, and Aboodarda, SJ. Ischemic preconditioning, but not priming exercise, improves exercise performance in trained rock climbers. J Strength Cond Res 37(11): 2149-2157, 2023-To assess the effects of ischemic preconditioning (IPC) and priming exercise on exercise tolerance and performance fatigability in a rock climbing-specific task, 12 rock climbers completed familiarization and baseline tests, and constant-load hangboarding tests (including 7 seconds on and 3 seconds off at an intensity estimated to be sustained for approximately 5 minutes) under 3 conditions: (a) standardized warm-up (CON), (b) IPC, or (c) a priming warm-up (PRIME). Neuromuscular responses were assessed using the interpolated twitch technique, including maximum isometric voluntary contraction (MVC) of the finger flexors and median nerve stimulation, at baseline and after the performance trial. Muscle oxygenation was measured continuously using near-infrared spectroscopy (NIRS) across exercise. Time to task failure (T lim ) for IPC (316.4 ± 83.1 seconds) was significantly greater than CON (263.6 ± 69.2 seconds) ( p = 0.028), whereas there was no difference between CON and PRIME (258.9 ± 101.8 seconds). At task failure, there were no differences in MVC, single twitch force, or voluntary activation across conditions; however, recovery of MVC and single twitch force after the performance trial was delayed for IPC and PRIME compared with CON ( p < 0.05). Despite differences in T lim , there were no differences in any of the NIRS variables assessed. Overall, despite exercise tolerance being improved by an average of 20.0% after IPC, there were no differences in neuromuscular responses at task failure, which is in line with the notion of a critical threshold of peripheral fatigue. These results indicate that IPC may be a promising precompetition strategy for rock climbers, although further research is warranted to elucidate its mechanism of action.

Ischemic preconditioning attenuates endoplasmic reticulum stress-dependent apoptosis of hepatocytes by regulating autophagy in hepatic ischemia-reperfusion injury.

Hepatic ischemia-reperfusion injury (HIRI) usually occurs during subtotal hepatectomy and severely damages liver function during the perioperative period. Endoplasmic reticulum stress (ERS) dependent apoptosis has been suggested to play a crucial role in HIRI progression. The present study focused on the regulatory effect of autophagy activation induced by ischemic preconditioning (IPC) on ERS-dependent apoptosis of hepatocytes in HIRI. A HIRI mouse model and oxygen-glucose deprivation/reperfusion (OGD/R) AML-12 hepatocyte cell lines were constructed to evaluate the protective effect of IPC in vivo and in vitro. The protein levels of p-eIF2α, CHOP, and cleaved caspase-12 were used to evaluate the ERS-dependent apoptosis, whereas LC3-II and p62 were considered as the autophagy activation markers. The beneficial molecular chaperones GRP78, HSP60, and HSP70 were also tested to evaluate autophagy. HIRI significantly increased ERS-dependent apoptosis markers and the number of apoptotic cells and damaged liver function. The ERS inhibitor salubrinal significantly alleviated liver injury in HIRI and OGD/R hepatocytes. Furthermore, both remote IPC and direct IPC significantly alleviated liver injury and inflammatory cell infiltration. IPC also upregulated LC3-II, downregulated p62 expression, and increased the mRNA levels of GRP78, HSP60, and HSP70 in HIRI mice and OGD/R hepatocytes, indicating the activation of autophagy by IPC. The autophagy inhibitor 3-methyladenine significantly attenuated the protective effects of IPC on ERS-dependent apoptosis and liver function, whereas the autophagy activator rapamycin mimicked the protective effects of IPC on ERS-dependent apoptosis in vivo and in vitro, suggesting a regulatory role of autophagy in ERS-dependent apoptosis. These results demonstrated that IPC could induce moderate autophagy and upregulate a few molecular chaperones to strengthen endogenous defense mechanisms, which is beneficial for alleviating ERS-dependent apoptosis and protecting hepatocytes from HIRI.

Prospective Evaluation of a Universally Applied Laparoscopic Gastric Ischemic Preconditioning Protocol Prior to Esophagectomy with Comparison with Historical Controls.

BACKGROUND: Anastomotic leak after esophagectomy is associated with significant morbidity and mortality. Our institution began performing laparoscopic gastric ischemic preconditioning (LGIP) with ligation of the left gastric and short gastric vessels prior to esophagectomy in all patients presenting with resectable esophageal cancer. We hypothesized that LGIP may decrease the incidence and severity of anastomotic leak. METHODS: Patients were prospectively evaluated following the universal application of LGIP prior to esophagectomy protocol in January 2021 until August 2022. Outcomes were compared with patients who underwent esophagectomy without LGIP from a prospectively maintained database from 2010 to 2020. RESULTS: We compared 42 patients who underwent LGIP followed by esophagectomy with 222 who underwent esophagectomy without LGIP. Age, sex, comorbidities, and clinical stage were similar between groups. Outpatient LGIP was generally well tolerated, with one patient experiencing prolonged gastroparesis. Median time from LGIP to esophagectomy was 31 days. Mean operative time and blood loss were not significantly different between groups. Patients who underwent LGIP were significantly less likely to develop an anastomotic leak following esophagectomy (7.1% vs. 20.7%, p = 0.038). This finding persisted on multivariate analysis [odds ratio (OR) 0.17, 95% confidence interval (CI) 0.03-0.42, p = 0.029]. The occurrence of any post-esophagectomy complication was similar between groups (40.5% vs. 46.0%, p = 0.514), but patients who underwent LGIP had shorter length of stay [10 (9-11) vs. 12 (9-15), p = 0.020]. CONCLUSIONS: LGIP prior to esophagectomy is associated with a decreased risk of anastomotic leak and length of hospital stay. Further, multi-institutional studies are warranted to confirm these findings.

Quantitative assessment of gastric ischemic preconditioning on conduit perfusion in esophagectomy: propensity score weighting study.

BACKGROUND: Gastric ischemic preconditioning prior to esophagectomy has been studied as a method to improve gastric conduit perfusion and reduce anastomotic complications, without conclusive results. The aim of this study is to evaluate the feasibility and safety of gastric ischemic preconditioning in terms of post-operative outcomes and quantitative gastric conduit perfusion. METHODS: Patients who underwent an esophagectomy with gastric conduit reconstruction between January 2015 and October 2022 at a single high-volume academic center were reviewed. Patient characteristics, surgical approach, post-operative outcomes, and indocyanine green fluorescence angiography data (ingress index for arterial inflow and ingress time for venous outflow, and the distance from the last gastroepiploic branch to the perfusion assessment point) were analyzed. Two propensity score weighting methods were used to investigate whether gastric ischemic preconditioning reduces anastomotic leaks. Multiple linear regression analysis was used to evaluate the conduit perfusion quantitatively. RESULTS: There were 594 esophagectomies with gastric conduit performed, with 41 having a gastric ischemic preconditioning. Among 544 with cervical anastomoses, leaks were seen in 2/30 (6.7%) in the ischemic preconditioning group and 114/514 (22.2%) in the control group (p = 0.041). Gastric ischemic preconditioning significantly reduced anastomotic leaks on both weighting methods (p = 0.037 and 0.047, respectively). Ingress index and time of the gastric conduit with ischemic preconditioning were significantly better than those without preconditioning (p = 0.013 and 0.025, respectively) after removing the effect of the distance from the last gastroepiploic branch to the perfusion assessment point. CONCLUSION: Gastric ischemic preconditioning results in a statistically significant improvement in conduit perfusion and reduction in post-operative anastomotic leaks.

Effects of remote ischaemic preconditioning on myocardial injury after major abdominal surgery in patients at high risk for cardiovascular adverse events in China (RIPC-MAS): protocol for a randomised, sham-controlled, observer-blinded trial.

INTRODUCTION: Myocardial injury after non-cardiac surgery (MINS) caused by an ischaemic mechanism is common and is associated with adverse short-term and long-term prognoses. However, MINS is a recent concept, and few studies have prospectively used it as a primary outcome. Remote ischaemic preconditioning (RIPC) is a non-invasive procedure that induces innate cardioprotection and may reduce MINS. METHODS AND ANALYSIS: This is a multicentre, randomised, sham-controlled, observer-blinded trial. Patients with a high clinical risk of cardiovascular events who are scheduled to undergo major abdominal surgery will be enrolled. A total of 766 participants will be randomised (1:1 ratio) to receive RIPC or control treatment before anaesthesia. RIPC will comprise four cycles of cuff inflation for 5 min to 200 mm Hg and deflation for 5 min. In the controls, an identical-looking cuff will be placed around the arm but will not be actually inflated. The primary outcome will be MINS, defined as at least one postoperative cardiac troponin (cTn) concentration above the 99th percentile upper reference limit of the cTn assay as a result of a presumed ischaemic mechanism. This trial will test the concentration of high-sensitivity cardiac troponin T (hs-cTnT). The secondary outcomes will be hs-cTnT levels reaching/above the prognostically important thresholds, peak hs-cTnT and total hs-cTnT release during the initial 3 days after surgery, length of hospital stay after surgery, length of stay in the intensive care unit, myocardial infarction, major adverse cardiovascular events, cardiac-related death, all-cause death within 30 days, 6 months, 1 year and 2 years after surgery, and postoperative complications and adverse events within 30 days after surgery. ETHICS AND DISSEMINATION: This study protocol (version 5.0 on 7 April 2023) was approved by the Ethics Committee of Sixth Affiliated Hospital of Sun Yat-sen University. The findings will be published in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT05733208.

Effects of Iron Nanoparticles Administration on Ischemia/Reperfusion Injury in Isolated Hearts of Male Wistar Rats.

Iron is an essential mineral participating in numerous biological processes in the organism under physiological conditions. However, it may be also involved in the pathological mechanisms activated in various cardiovascular diseases including myocardial ischemia/reperfusion (I/R) injury, due to its involvement in reactive oxygen species (ROS) production. Furthermore, iron has been reported to participate in the mechanisms of iron-dependent cell death defined as "ferroptosis". On the other hand, iron may be also involved in the adaptive processes of ischemic preconditioning (IPC). This study aimed to elucidate whether small amounts of iron may modify the cardiac response to I/R in isolated perfused rat hearts and their protection by IPC. Pretreatment of the hearts with iron nanoparticles 15 min prior to sustained ischemia (iron preconditioning, Fe-PC) did not attenuate post-I/R contractile dysfunction. Recovery of left ventricular developed pressure (LVDP) was significantly improved only in the group with combined pretreatment with iron and IPC. Similarly, the rates of contraction and relaxation [+/-(dP/dt)max] were almost completely restored in the group preconditioned with a combination of iron and IPC but not with iron alone. In addition, the severity of reperfusion arrhythmias was reduced only in the iron+IPC group. No changes in protein levels of "survival" kinases of the RISK pathway (Reperfusion Injury Salvage Kinase) were found except for reduced caspase 3 levels in both preconditioned groups. The results indicate that a failure to precondition rat hearts with iron may be associated with the absent upregulation of RISK proteins and the pro-ferroptotic effect manifested by reduced glutathione peroxidase 4 (GPX4) levels. However, combination with IPC suppressed the negative effects of iron resulting in cardioprotection.

Is Renal Ischemic Preconditioning an Alternative to Ameliorate the Short- and Long-Term Consequences of Acute Kidney Injury?

Acute kidney injury (AKI) is a global health problem and has recently been recognized as a risk factor for developing chronic kidney disease (CKD). Unfortunately, there are no effective treatments to reduce or prevent AKI, which results in high morbidity and mortality rates. Ischemic preconditioning (IPC) has emerged as a promising strategy to prevent, to the extent possible, renal tissue from AKI. Several studies have used this strategy, which involves short or long cycles of ischemia/reperfusion (IR) prior to a potential fatal ischemic injury. In most of these studies, IPC was effective at reducing renal damage. Since the first study that showed renoprotection due to IPC, several studies have focused on finding the best strategy to activate correctly and efficiently reparative mechanisms, generating different modalities with promising results. In addition, the studies performing remote IPC, by inducing an ischemic process in distant tissues before a renal IR, are also addressed. Here, we review in detail existing studies on IPC strategies for AKI pathophysiology and the proposed triggering mechanisms that have a positive impact on renal function and structure in animal models of AKI and in humans, as well as the prospects and challenges for its clinical application.

Efficacy and safety of remote ischemic conditioning for acute ischemic stroke: A comprehensive meta-analysis from randomized controlled trials.

BACKGROUND AND PURPOSE: Remote ischemic conditioning (RIC) is a remote, transient, and noninvasive procedure providing temporary ischemia and reperfusion. However, there is no comprehensive literature investigating the efficacy and safety of RIC for the treatment of acute ischemic stroke. In the present study, we performed a comprehensive meta-analysis of the available studies. METHODS: MEDLINE, Embase, the Cochrane Library database (CENTRAL), and ClinicalTrials.gov were searched before Sep 7, 2022. The data were analyzed using Review Manager 5.4.1 software, Stata version 16.0 software, and R 4.2.0 software. Odds ratio (OR), mean difference (MD), and corresponding 95% CIs were pooled using fixed-effects meta-analysis. RESULTS: We pooled 6392 patients from 17 randomized controlled trials. Chronic RIC could reduce the recurrence of ischemic stroke at the endpoints (OR 0.67, 95% CI [0.51, 0.87]). RIC could also improve the prognosis of patients at 90 days as assessed by mRS score (mRS 0-1: OR 1.29, 95% CI [1.09, 1.52]; mRS 0-2: OR 1.22, 95% CI [1.01, 1.48]) and at the endpoints assessed by NIHSS score (MD -0.99, 95% CI [-1.45, -0.53]). RIC would not cause additional adverse events such as death (p = 0.72), intracerebral hemorrhage events (p = 0.69), pneumonia (p = 0.75), and TIA (p = 0.24) but would inevitably cause RIC-related adverse events (OR 26.79, 95% CI [12.08, 59.38]). CONCLUSIONS: RIC could reduce the stroke recurrence and improve patients' prognosis. Intervention on bilateral upper limbs, 5 cycles, and a length of 50 min in each intervention might be an optimal protocol for RIC at present. RIC could be an effective therapy for patients not eligible for reperfusion therapy. RIC would not cause other adverse events except for relatively benign RIC-related adverse events.

Time from Onset to Remote Ischemic Conditioning and Clinical Outcome After Acute Moderate Ischemic Stroke.

OBJECTIVE: We conducted a post hoc exploratory analysis of Remote Ischemic Conditioning for Acute Moderate Ischemic Stroke (RICAMIS) to determine whether early remote ischemic conditioning (RIC) initiation after stroke onset was associated with clinical outcome in patients with acute moderate ischemic stroke. METHODS: In RICAMIS, patients receiving RIC treatment in the intention-to-treat analysis were divided into 2 groups based on onset-to-treatment time (OTT): early RIC group (OTT ≤ 24 hours) and late RIC group (OTT 24-48 hours). Patients receiving usual care without RIC treatment from intention-to-treat analysis were assigned as the control group. The primary outcome was excellent functional outcome at 90 days. RESULTS: Among 1,776 patients from intention-to-treat analysis, 387 were in the early RIC group, 476 in the late RIC group, and 913 in the control group. In the post hoc exploratory analysis, a higher proportion of excellent functional outcome was found in the early RIC versus control group (adjusted absolute difference = 8.1%, 95% confidence interval [CI] = 2.5%-13.8%, p = 0.005), but no difference in outcomes was detected in the late RIC versus control group (adjusted absolute difference = 3.3%, 95% CI = -2.1% to 8.6%, p = 0.23), or in the early RIC versus late RIC group (adjusted absolute difference = 5.0%, 95% CI = -1.3% to 11.2%, p = 0.12). Similar results were found in the per-protocol analysis. INTERPRETATION: Among patients with acute moderate ischemic stroke who are not candidates for intravenous thrombolysis or endovascular therapy, early RIC initiation within 24 hours of onset may be associated with higher likelihood of excellent clinical outcome. ANN NEUROL 2023;94:561-571.