Protective effects of propofol against ischemia/reperfusion injury in rat kidneys

Effects of Anesthetic Technique on the Occurrence of Acute Kidney Injury after Spine Surgery: A Retrospective Cohort Study

The effects of anesthetics on acute kidney injury (AKI) after spine surgery have not been evaluated fully. This study compared propofol-based total intravenous anesthesia (TIVA) and volatile anesthetics in the development of AKI after spine surgery. This retrospective study reviewed patients who underwent spine surgery between 2015 and 2019. A logistic regression analysis was performed to identify risk factors for AKI. Additionally, after propensity score matching, the incidence of AKI was compared between TIVA and volatile groups. Of the 4473 patients, 709 were excluded and 3764 were included in the logistic regression. After propensity score matching, 766 patients from each group were compared, and we found that the incidence of AKI was significantly lower in the TIVA group (1% vs. 4.2%, p < 0.001). In the multivariate logistic regression analysis, the risk factors for postoperative AKI were male sex (OR 1.85, 95% CI 1.18–3.06), hypertension (OR 2.48, 95% CI 1.56–3.94), anemia (OR 2.66, 95% CI 1.76–4.04), and volatile anesthetics (OR 4.69, 95% CI 2.24–9.84). Compared with volatile anesthetics, TIVA is associated with a reduced risk of AKI for patients who have undergone spine surgery.

Anesthetics mediated the immunomodulatory effects via regulation of TLR signaling

Anesthetics have been widely used in surgery and found to suppress inflammatory injury and affect the outcomes of the surgery and diseases. In contrast, anesthetics are also found to induce neuronal injury and inflammation. However, the immune-modulation mechanism of anesthetics is still not clear. Recent studies have shown that the immune-modulation of anesthetics is associated with the regulation of toll-like receptor (TLR)-mediated signaling. Moreover, the regulation of anesthetics in TLR signaling is related to modulations of non-coding RNAs (nc RNAs). Consistently, nc RNAs are mainly divided into micro RNAs (miRs) and long non-coding RNAs (lnc RNAs), which have been found to exert regulatory effects on the immune system. In this review, we summarize the immunomodulatory functions of the widely used anesthetic agents, which are associated with regulation of TLR signaling. In addition, we also focus on the roles of nc RNAs induced by anesthetics in regulations of TLR signaling.

Propofol ameliorates renal ischemia/reperfusion injury by enhancing macrophage M2 polarization through PPARγ/STAT3 signaling

Propofol (Pro) confers protection against renal ischemia/reperfusion (rI/R) injury through incompletely characterized mechanisms. Since Pro has shown net anti-inflammatory properties as part of its beneficial effects, we examined the potential role of Pro in the modulation of macrophage polarization status during both rI/R injury in vivo and exposure of cultured peritoneal macrophages (PMs) to hypoxia/reoxygenation (H/R). Rats were subjected to 45-min r/IR surgery or a sham procedure and administered PBS (vehicle) or Pro during the ischemia stage. Pro administration attenuated rI/R-induced kidney damage and renal TNF-α, IL-6, and CXCL-10 expression. Enhanced macrophage M2 polarization, evidenced by reduced iNOS and increased Arg1 and Mrc1 mRNA levels, was further detected after Pro treatment both in the kidney, after rI/R in vivo, and in H/R-treated PMs. Pro administration also repressed phosphorylated signal transducer and activator of transcription 1 (p-STAT1) and increased p-STAT3, p-STAT6, and peroxisome proliferator-activated receptor-γ (PPARγ) mRNA levels in H/R-exposed PMs. Importantly, siRNA-mediated PPARγ silencing repressed Pro-mediated STAT3 activation in PMs and restored proinflammatory cytokine levels and prevented macrophage M2 marker expression in both rI/R-treated rats and cultured PMs. These findings suggest that Pro confers renoprotection against rI/R by stimulating PPARγ/STAT3-dependent macrophage conversion to the M2 phenotype.

Preparation and Monitoring of Small Animals in Renal MRI

Renal diseases remain devastating illnesses with unacceptably high rates of mortality and morbidity worldwide. Animal models are essential tools to better understand the pathomechanism of kidney-related illnesses and to develop new, successful therapeutic strategies. Magnetic resonance imaging (MRI) has been actively explored in the last decades for assessing renal function, perfusion, tissue oxygenation as well as the degree of fibrosis and inflammation. This chapter aims to provide an overview of the preparation and monitoring of small animals before, during, and after surgical interventions or MR imaging. Standardization of experimental settings such as body temperature or hydration of animals and minimizing pain and distress are essential for diminishing nonexperimental variables as well as for conducting ethical research.This publication is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers.

The effects of gasotransmitters inhibition on biochemical and haematological parameters and oxidative stress in propofol-anaesthetized Wistar male rats

This study aimed to investigate the effects of propofol through evaluating its interaction with nitric oxide (NO), hydrogen sulfide (H2S), and carbon monoxide (CO). Wistar male rats were divided in 4 groups: (1) bolus injection of propofol (1% 10 mg/mL, 100 mg/kg bw, i.p.); (2) Nω-nitro-l-arginine methyl ester (L-NAME; NO synthase inhibitor, 60 mg/kg bw, i.p.) + bolus injection of propofol (1% 10 mg/mL, 100 mg/kg bw, i.p.); (3) DL-propargylglycine (DL-PAG; H2S synthase inhibitor, 50 mg/kg bw, i.p.) + bolus injection of propofol (1% 10 mg/mL, 100 mg/kg bw, i.p.); (4) zinc protoporphyrin IX (ZnPPIX; CO synthase inhibitor, 50 μmol/kg bw, i.p.) + bolus injection of propofol (1% 10 mg/mL, 100 mg/kg bw, i.p.). Increased levels of albumins, low-density lipoproteins, alkaline phosphatase, amylase, high-sensitivity Troponin T, and fibrinogen were found in L-NAME + propofol group. Platelet crit, platelet count, total cholesterol, and high-density lipoproteins were elevated in ZnPPIX + propofol group. Hydrogen peroxide was increased in all groups treated with gasotransmitters inhibitors. Reduced glutathione was reduced in all groups, superoxide dismutase activity only in L-NAME + propofol. The effect of propofol on various biochemical, haematological, and oxidative stress markers may be at least in part mediated through interaction with 3 estimated gasotransmitters.

Opioids Preconditioning Upon Renal Function and Ischemia-Reperfusion Injury: A Narrative Review

Kidneys have an important role in regulating water volume, blood pressure, secretion of hormones and acid-base and electrolyte balance. Kidney dysfunction derived from acute injury can, under certain conditions, progress to chronic kidney disease. In the late stages of kidney disease, treatment is limited to replacement therapy: Dialysis and transplantation. After renal transplant, grafts suffer from activation of immune cells and generation of oxidant molecules. Anesthetic preconditioning has emerged as a promising strategy to ameliorate ischemia reperfusion injury. This review compiles some significant aspects of renal physiology and discusses current understanding of the effects of anesthetic preconditioning upon renal function and ischemia reperfusion injury, focusing on opioids and its properties ameliorating renal injury. According to the available evidence, opioid preconditioning appears to reduce inflammation and reactive oxygen species generation after ischemia reperfusion. Therefore, opioid preconditioning represents a promising strategy to reduce renal ischemia reperfusion injury and, its application on current clinical practice could be beneficial in events such as acute renal injury and kidney transplantation.

Cox-2 Negatively Affects the Protective Role of Propofol against Hypoxia/Reoxygenation Induced Cardiomyocytes Apoptosis through Suppressing Akt Signaling

Nowadays, the prevention of severe myocardium injury resulting from myocardial ischemia/reperfusion injury (I/R) has been recognized as an important subject in the field of ischemic heart disease. In this study, H9c2 cardiomyocytes were exposed to cycles of hypoxia/reoxygenation (H/R) to mimic myocardial I/R injury. Western blot analysis and qRT-PCR were performed to detect the expression of Cox-2, Akt and p-Akt. Cell viability, LDH release and activity of Caspase-3 were assessed to determine the protective effect of propofol. The results proved that the protective effect of propofol for H/R challenged cardiomyocytes was associated with Akt phosphorylation. We also revealed that treatment of propofol suppressed the expression of Cox-2 in cardiomyocytes which was up-regulated after H/R treatment. Conversely, the over-expression of Cox-2 inhibited Akt phosphorylation while enhancing cardiomyocytes apoptosis. Interestingly, Akt activator exhibited similar protective effect with propofol and could diminish the influences brought by over-expression of Cox-2. Thus, it could be concluded that Cox-2 negatively affects the protective effect of propofol against hypoxia/reoxygenation induced cardiomyocyte apoptosis by suppressing Akt phosphorylation.

Isoflurane Increases Tolerance to Renal Ischemia Reperfusion Injury Compared to Propofol: An Experimental Study in Pigs

Purpose: To compare two clinically relevant anesthetic agents, i.e., isoflurane versus propofol with respect to protection of the kidney in a porcine renal ischemia reperfusion model. Materials and Methods: 14 hybrid pigs were randomized to anesthesia with either isoflurane or propofol prior to laparoscopic surgery. Following anesthesia, the left kidney hilum was clamped for 60 min and the right kidney removed. After 48 h of reperfusion, urine was sampled for analysis of neutrophil gelatinase-associated lipocalin (NGAL), albumin, and creatinine. The left kidney was harvested for histologic scoring of injury. Results: Histologic examination of renal injury revealed a statistically significant difference in favor of isoflurane on denuded basement membrane score (isoflurane group 1.58 ± 0.38 vs. propofol 2.42 ± 0.80, p = .026). Median (25-75 percentile) urinary albumin 3.4 g/L (2.25-7.48) vs. 8.9 g/L (3.73-13.8), (p = .041) and urinary albumin/creatinine ratio 1.17 (0.76-1.82) vs. 1.76 (1.63-5.99), (p = .026) were both significantly lower in the isoflurane group. Median (25-75 percentile) urinary NGAL was 167 (51-215) pg/ml in the isoflurane group compared with 362 (149-508) pg/ml in the propofol group (p = .093). Conclusion: Isoflurane increases tolerance to renal ischemia reperfusion injury compared to propofol in this model.

Propofol Attenuates Airway Inflammation in a Mast Cell-Dependent Mouse Model of Allergic Asthma by Inhibiting the Toll-like Receptor 4/Reactive Oxygen Species/Nuclear Factor κB Signaling Pathway

Propofol, an intravenous anesthetic agent widely used in clinical practice, is the preferred anesthetic for asthmatic patients. This study was designed to determine the protective effect and underlying mechanisms of propofol on airway inflammation in a mast cell-dependent mouse model of allergic asthma. Mice were sensitized by ovalbumin (OVA) without alum and challenged with OVA three times. Propofol was given intraperitoneally 0.5 h prior to OVA challenge. The inflammatory cell count and production of cytokines in the bronchoalveolar lavage fluid (BALF) were detected. The changes of lung histology and key molecules of the toll-like receptor 4 (TLR4)/reactive oxygen species (ROS)/NF-κB signaling pathway were also measured. The results showed that propofol significantly decreased the number of eosinophils and the levels of IL-4, IL-5, IL-6, IL-13, and TNF-α in BALF. Furthermore, propofol significantly attenuated airway inflammation, as characterized by fewer infiltrating inflammatory cells and decreased mucus production and goblet cell hyperplasia. Meanwhile, the expression of TLR4, and its downstream signaling adaptor molecules--myeloid differentiation factor 88 (MyD88) and NF-κB, were inhibited by propofol. The hydrogen peroxide and methane dicarboxylic aldehyde levels were decreased by propofol, and the superoxide dismutase activity was increased in propofol treatment group. These findings indicate that propofol may attenuate airway inflammation by inhibiting the TLR4/MyD88/ROS/NF-κB signaling pathway in a mast cell-dependent mouse model of allergic asthma.

A Review of Anesthetic Effects on Renal Function: Potential Organ Protection

BACKGROUND

Renal protection is a critical concept for anesthesiologists, nephrologists, and urologists, since anesthesia and renal function are highly interconnected and can potentially interfere with one another. Therefore, a comprehensive understanding of anesthetic drugs and their effects on renal function remains fundamental to the success of renal surgeries, especially transplant procedures. Some experimental studies have shown that some anesthetics provide protection against renal ischemia/reperfusion (IR) injury, but there is limited clinical evidence.

SUMMARY

The effects of anesthetic drugs on renal failure are particularly important in the context of kidney transplantation, since the conditions of preservation following removal profoundly influence the recovery of organ function. Currently, preservation procedures are typically based on the usage of a cold-storage solution. Some anesthetic drugs induce anti-inflammatory, anti-necrotic, and anti-apoptotic effects. A more thorough understanding of anesthetic effects on renal function can present a novel approach for developing organ-protective strategies. The aim of this review is to discuss the effects of different anesthetic drugs on renal function, with particular focus on IR injury. Many studies have demonstrated the organ-protective effects of some anesthetic drugs, specifically propofol, which indicate the potential of some anesthetics to introduce novel organ protective targets. This is not surprising, since lipid emulsions are major components of propofol, which accumulating data show provide organ protective effects against IR injury. Key Messages: Thorough understanding of the interaction between anesthetic drugs and renal function remains fundamental to the delivery of safe perioperative care and to optimizing outcomes after renal surgeries, particularly transplant procedures. Anesthetics can be repurposed for organ protection with more information about their effects, especially during transplant procedures. Here, we review the effects of different anesthetic drugs - specifically those that contain lipids in their structure, with special reference to IR injury.

Renal ischemia/reperfusion injury; from pathophysiology to treatment

Ischemia/reperfusion injury (IRI) is caused by a sudden temporary impairment of the blood flow to the particular organ. IRI usually is associated with a robust inflammatory and oxidative stress response to hypoxia and reperfusion which disturbs the organ function. Renal IR induced acute kidney injury (AKI) contributes to high morbidity and mortality rate in a wide range of injuries. Although the pathophysiology of IRI is not completely understood, several important mechanisms resulting in kidney failure have been mentioned. In ischemic kidney and subsequent of re-oxygenation, generation of reactive oxygen species (ROS) at reperfusion phase initiates a cascade of deleterious cellular responses leading to inflammation, cell death, and acute kidney failure. Better understanding of the cellular pathophysiological mechanisms underlying kidney injury will hopefully result in the design of more targeted therapies to prevent and treatment the injury. In this review, we summarize some important potential mechanisms and therapeutic approaches in renal IRI.

Effects of propofol on renal ischemia/reperfusion injury in rats

Renal ischemia/reperfusion injury (IRI) is a major cause of acute renal failure. The aim of this study was to investigate whether propofol pretreatment in a rat model protects kidney tissue against IRI. Thirty-two Wistar rats were equally divided into four groups: a sham-operated group, untreated renal IRI group, and low-dose (5 mg/kg) and high-dose (10 mg/kg) propofol-treated groups which were treated with propofol prior to the induction of IRI. The rats were subjected to renal ischemia by bilateral clamping of the pedicles for 50 min, followed by reperfusion. The low-dose and high-dose propofol treatment groups were pretreated via femoral vein injection with a propofol suspension prior to the induction of ischemia/reperfusion. The untreated IRI group showed significantly higher serum creatinine (SCr), blood urea nitrogen (BUN), interleukin 6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α), and malondialdehyde (MDA) levels compared with the sham-operated rats. Superoxide dismutase (SOD) levels were significantly reduced following IRI; however, they significantly increased following propofol administration. Bone morphogenetic protein 2 (BMP2) levels were significantly increased in the propofol-treated groups compared with the untreated IRI group. These results suggest that propofol reduces renal oxidative injury and facilitates repair following IRI. Propofol may play a protective role by regulating BMP2 expression in renal IRI.

Propofol participates in gastric mucosal protection through inhibiting the toll-like receptor-4/nuclear factor kappa-B signaling pathway

AIMS

Propofol has demonstrated protective effects against digestive injury. Toll-like receptor-4 (TLR4) is involved in gastric mucosal injury. However, it has not yet been clarified whether propofol protects gastric mucosa from ethanol-induced injury and whether the mechanism involved is related to TLR4 activation. Therefore, this prospective study was carried out to address the issue.

METHODS

Gastric mucosal injury was induced in mice by intragastric administration of ethanol. Propofol was given intraperitoneally 30 min before ethanol intragastric administration and, 1h later, gastric specimens were studied using hematoxylin--eosin staining, quantitative real-time RT-PCR, immunohistochemical staining and Western blot assays; serum specimens were studied using ELISA kits.

RESULTS

Propofol at 25mg/kg significantly attenuated ethanol-induced gastric mucosal injury. In addition, propofol pretreatment significantly inhibited the upregulated expression of high-mobility group box-1 (HMGB1) protein, TLR4 and its downstream signaling molecules--myeloid differentiation factor 88 (MyD88) and nuclear factor kappa-B (NF-κB)--in gastric mucosa, while suppressing the increased release of tumor neurosis factor-α (TNF-α) and interleukin-1β (IL-1β) in serum. Furthermore, upregulation of the Bax/Bcl-2 ratio in gastric mucosa was clearly depressed by propofol.

CONCLUSION

Propofol can inhibit HMGB1 expression and TLR4/MyD88/NF-κB-mediated inflammatory responses, and hamper apoptosis, which may contribute to its protective action against ethanol-induced gastric mucosal injury.

Protective effects of propofol against hydrogen peroxide-induced oxidative stress in human kidney proximal tubular cells

Background

We investigated the protective effects of propofol in the HK-2 cell line of human kidney proximal tubular cells against hydrogen peroxide (H₂O₂)-induced oxidative stress.

Methods

After pretreatment with different concentrations of propofol (0 µM, 10 µM, 25 µM and 50 µM) for 30 minutes, HK-2 cells were exposed to 8 mM H₂O₂ for 4 hours. Cell death was assessed by measuring the percentage of lactate dehydrogenase (LDH) release and by counting viable cells. The nature of cell death was assessed by doubles-taining cells with fluorescein isothiocyanate-labeled Annexin V and propidium iodide, and then analyzing the cells using flow cytometry.

Results

After exposure to 8 mM H₂O₂ for 4 hours, the percentage of LDH release was 45.1 ± 4.2% and the number of viable HK-2 cells was 5.2 ± 6.0%. Pretreatment with propofol suppressed H₂O₂-induced LDH release in a concentration-dependent manner, reducing the percentage of LDH release to 38.1 ± 5.6%, 33.5 ± 6.3%, and 26.2 ± 3.8% of the controls at 10 µM, 25 µM and 50 µM propofol, respectively. Numbers of viable cells increased following propofol pretreatment, with 11.4 ± 10.9%, 19.5 ± 16.1%, and 32.4 ± 23.3% cell survival rates after pretreatment with 10 µM, 25 µM and 50 µM propofol, respectively. Analyses of flow cytometry showed that the propofol pretreatment decreased the percentage of necrotic and late apoptotic cells.

Conclusions

Propofol protects HK-2 human kidney proximal tubular cells against H₂O₂-induced oxidative stress.

Effect of propofol on proliferation and apoptosis of gastric mucosal cells in gastric ischemia-reperfusion injury in mice

AIM: To observe the changes in proliferation and apoptosis of gastric mucosal cells in gastric ischemia-reperfusion (I/R) injury, and to clarify whether propofol has a gastric protection effect and the possible mechanisms involved.

METHODS: Seventy-two Kunming mice were randomly divided into four groups: sham operation group, I/R injury group, fat emulsion group, and propofol group. Except the sham operation group, I/R injury was induced in other groups by clamping the celiac artery for 30 min and allowing reperfusion for 1h. The mice were finally sacrificed to observe morphological changes and investigate gastric mucosal damage index (GMDI). The histological changes of the stomach were observed using light microscopy. The content of malondialdehyde (MDA) and activity of superoxide dismutas (SOD) in gastric mucosal cells were measured by colorimetry analysis. Immunohistochemistry and TdT-mediated d-UTP-biotin nick end-labeling (TUNEL) assay were used to observe PCNA expression and apoptosis in gastric mucosa, and the expression of Bax and Bcl-2 proteins was determined by Western blot.

RESULTS: Severe mucosal lesions induced by gastric I/R were considerably reduced following administration of propofol (25 mg/kg); mucosal and submueosal hyperemia, edema, and deep erosion were improved significantly. Compared to the I/R group, treatment with propofol significantly reduced gastric mucosal MDA content and cell apoptosis (33.9% ± 1.3% vs 60.8% ± 6.9%, P < 0.01), enhanced SOD activity, promoted cell proliferation (16.0% ± 1.8% vs 6.4% ± 1.2%, P < 0.01), and regulated Bax (0.453 ± 0.025 vs 0.268 ± 0.023, P < 0.01) and Bcl-2 (0.513 ± 0.014 vs 0.752 ± 0.015, P < 0.01) protein expression.

CONCLUSION: Propofol protects against gastric gastric I/R injury possibly by promoting gastric mucosal cell proliferation and inhibiting apoptosis.

Antioxidant effects of propofol on tourniquet-induced ischemia-reperfusion injury: an experimental study

PURPOSE

This experimental study aimed to investigate the antioxidant effects of propofol anesthesia at induction doses in a rat skeletal muscle ischemia/reperfusion injury model.

METHODS

Twenty-six rats were randomly divided into three groups to receive one of the following interventions: sham operation (n = 6), ischemia/reperfusion (I/R) injury (n = 10), or propofol administration in addition to I/R injury (n = 10). I/R injury was attained by 2-h clamping of femoral artery followed by 3-h perfusion. Then blood and tissue samples were collected for biochemical analysis and histopathologic examination. Glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) enzyme activities and nitric oxide (NO) and malondialdehyde (MDA) levels were measured in both plasma and muscle tissue. In addition, catalase (CAT) activity and protein carbonyl (PC) content were measured in muscle tissue.

RESULTS

I/R group had significantly higher SOD activity (9.05 versus 5.63 and 6.18 U/mL, P < 0.05) and NO level (46.77 versus 30.62 and 33.90 μmol/L, P < 0.05) compared with sham-operated group and I/R plus propofol group. In addition, GSH-Px activity of the I/R group was significantly higher than sham-operated group (1.26 versus 1.05 U/mL, P < 0.05). I/R group had significantly higher tissue activities of CAT (0.11 versus 0.06 and 0.04 k/g protein, P < 0.05) and SOD (0.12 versus 0.08 and 0.07 U/mg protein, P < 0.05) compared with the sham and I/R plus propofol group. Histopathologic examination showed that I/R plus propofol group had significantly lower degeneration (P = 0.021) and inflammation (P = 0.028) scores compared with I/R group.

CONCLUSION

Propofol anesthesia seems to enhance the antioxidant capacity against tourniquet induced ischemia-reperfusion injury.

Preservation strategies to reduce ischemic injury in kidney transplantation: pharmacological and genetic approaches

PURPOSE OF REVIEW

In the current graft shortage, it is paramount to improve the quality of transplanted organs. Organ preservation represents an underused therapeutic window with great potential to reduce ischaemia-reperfusion injury (IRI) and improve graft quality. Herein, we review strategies using this window as well as other promising work targeting IRI pathways using pharmacological treatments and gene therapy.

RECENT FINDINGS

We highlight studies using molecules administered during kidney preservation to target key components of IRI such as inflammation, oxidative stress, mitochondrial activity and the coagulation pathway. We further expose recent studies of gene therapy directed against inflammation or apoptosis during cold storage. Other pathways with potential therapeutic molecules are cited.

SUMMARY

The use of cold preservation as a therapeutic window to deliver pharmacological or gene therapy treatments can significantly improve both short-term and long-term graft outcomes. Even if human gene therapy remains hampered by the quantity of agent needed and the potential harmfulness of the vector, it clearly offers a wide array of possibilities for the future. Although gene therapy is still too immature, we expose pharmacological strategies which can readily be applied to the clinic and improve both transplantation success rates and the patients' quality of life.