Antioxidant and C5a-blocking strategy for hepatic ischemia-reperfusion injury repair

Current status and perspective on molecular targets and therapeutic intervention strategy in hepatic ischemia-reperfusion injury

Hepatic ischemia‒reperfusion injury (HIRI) is a common and inevitable complication of hepatic trauma, liver resection, or liver transplantation. It contributes to postoperative organ failure or tissue rejection, eventually affecting patient prognosis and overall survival. The pathological mechanism of HIRI is highly complex and has not yet been fully elucidated. The proposed underlying mechanisms include mitochondrial damage, oxidative stress imbalance, abnormal cell death, immune cell hyperactivation, intracellular inflammatory disorders and other complex events. In addition to serious clinical limitations, available antagonistic drugs and specific treatment regimens are still lacking. Therefore, there is an urgent need to not only clarify the exact etiology of HIRI but also reveal the possible reactions and bottlenecks of existing drugs, helping to reduce morbidity and shorten hospitalizations. We analyzed the possible underlying mechanism of HIRI, discussed various outcomes among different animal models and explored neglected potential therapeutic strategies for HIRI treatment. By thoroughly reviewing and analyzing the literature on HIRI, we gained a comprehensive understanding of the current research status in related fields and identified valuable references for future clinical and scientific investigations.

Structural analysis of the human C5a-C5aR1 complex using cryo-electron microscopy

The complement system is a complex network of proteins that plays a crucial role in the innate immune response. One important component of this system is the C5a-C5aR1 complex, which is critical in the recruitment and activation of immune cells. In-depth investigation of the activation mechanism as well as biased signaling of the C5a-C5aR1 system will facilitate the elucidation of C5a-mediated pathophysiology. In this study, we determined the structure of C5a-C5aR1-Gi complex at a high resolution of 3 Å using cryo-electron microscopy (Cryo-EM). Our results revealed the binding site of C5a, which consists of a polar recognition region on the extracellular side and an amphipathic pocket within the transmembrane domain. Furthermore, we found that C5a binding induces conformational changes of C5aR1, which subsequently leads to the activation of G protein signaling pathways. Notably, a key residue (M265) located on transmembrane helix 6 (TM6) was identified to play a crucial role in regulating the recruitment of β-arrestin driven by C5a. This study provides more information about the structure and function of the human C5a-C5aR1 complex, which is essential for the proper functioning of the complement system. The findings of this study can also provide a foundation for the design of new pharmaceuticals targeting this receptor with bias or specificity.

Mannose binding lectin-associated serine protease-1 is a novel contributor to myocardial ischemia/reperfusion injury

BACKGROUND

The lectin pathway has been demonstrated to play a critical role in the pathological process of myocardial ischemia/reperfusion injury (IRI). Mannose-binding lectin (MBL)-associated serine protease-1 (MASP-1), especially different from other components of the lectin pathway, mediates proinflammatory and procoagulant reactions independent of complement cascades. However, the role of MASP-1 in myocardial IRI remains unknown so far.

METHODS

Myocardial IRI was established with 45 min ischemia and 24 h reperfusion in mice. C1 inhibitor, as the natural inhibitor of MASP-1, was administrated at 20 IU/Kg via tail vein 5 min before surgical operation. Cardiac function and myocardial infarct size were assessed. Myocardial histology and fibrosis were evaluated by H&E and Masson staining, respectively. Deposition of MASP-1, expression of PAR-1/4 and neutrophil extracellular traps (NET) were investigated on myocardium tissue by IHC staining. Cell apoptosis was detected by TUNEL assay. Levels of myocardial enzymes and proinflammatory cytokines were determined by ELISA.

RESULTS

Inhibition of MASP-1 with C1 INH improved cardiac function and alleviated myocardium tissue injury (infarct size, enzymes, histology and fibrosis) after myocardial IRI. Deposition of MASP-1 and expression PAR-1, as well as NET formation in myocardial tissue were suppressed by MASP-1 inhibitor, while PAR-4 was elevated. Levels of apoptosis, HMGB-1 and IL-6 were lower after blocking MASP-1. Yet, IL-8 and TNF-α remained unchanged.

CONCLUSIONS

MASP-1, as a new contributor, played a critical role in myocardial IRI. Inhibition of MASP-1 protected myocardial tissue from IRI probably via regulation of PARs/NET pathway. This may provide a novel target strategy against myocardial IRI.

Stem cell-derived hepatocyte therapy using versatile biomimetic nanozyme incorporated nanofiber-reinforced decellularized extracellular matrix hydrogels for the treatment of acute liver failure

Reactive oxygen species (ROS)-associated oxidative stress, inflammation storm, and massive hepatocyte necrosis are the typical manifestations of acute liver failure (ALF), therefore specific therapeutic interventions are essential for the devastating disease. Here, we developed a platform consisting of versatile biomimetic copper oxide nanozymes (Cu NZs)-loaded PLGA nanofibers (Cu NZs@PLGA nanofibers) and decellularized extracellular matrix (dECM) hydrogels for delivery of human adipose-derived mesenchymal stem/stromal cells-derived hepatocyte-like cells (hADMSCs-derived HLCs) (HLCs/Cu NZs@fiber/dECM). Cu NZs@PLGA nanofibers could conspicuously scavenge excessive ROS at the early stage of ALF, and reduce the massive accumulation of pro-inflammatory cytokines, herein efficiently preventing the deterioration of hepatocytes necrosis. Moreover, Cu NZs@PLGA nanofibers also exhibited a cytoprotection effect on the transplanted HLCs. Meanwhile, HLCs with hepatic-specific biofunctions and anti-inflammatory activity acted as a promising alternative cell source for ALF therapy. The dECM hydrogels further provided the desirable 3D environment and favorably improved the hepatic functions of HLCs. In addition, the pro-angiogenesis activity of Cu NZs@PLGA nanofibers also facilitated the integration of the whole implant with the host liver. Hence, HLCs/Cu NZs@fiber/dECM performed excellent synergistic therapeutic efficacy on ALF mice. This strategy using Cu NZs@PLGA nanofiber-reinforced dECM hydrogels for HLCs in situ delivery is a promising approach for ALF therapy and shows great potential for clinical translation.

Self-Assembly of Selenium-Doped Carbon Quantum Dots as Antioxidants for Hepatic Ischemia-Reperfusion Injury Management

Hepatic ischemia-reperfusion injury (HIRI) is a critical complication after liver surgery that negatively affects surgical outcomes of patients with the end-stage liver-related disease. Reactive oxygen species (ROS) are responsible for the development of ischemia-reperfusion injury and eventually lead to hepatic dysfunction. Selenium-doped carbon quantum dots (Se-CQDs) with an excellent redox-responsive property can effectively scavenge ROS and protect cells from oxidation. However, the accumulation of Se-CQDs in the liver is extremely low. To address this concern, the fabrication of Se-CQDs-lecithin nanoparticles (Se-LEC NPs) is developed through self-assembly mainly driven by the noncovalent interactions. Lecithin acting as the self-assembly building block also makes a pivotal contribution to the therapeutic performance of Se-LEC NPs due to its capability to react with ROS. The fabricated Se-LEC NPs largely accumulate in the liver, effectively scavenge ROS and inhibit the release of inflammatory cytokines, thus exerting beneficial therapeutic efficacy on HIRI. This work may open a new avenue for the design of self-assembled Se-CQDs NPs for the treatment of HIRI and other ROS-related diseases.

New insight of complement system in the process of vascular calcification

The complement system defences against pathogenic microbes and modulates immune homeostasis by interacting with the innate and adaptive immune systems. Dysregulation, impairment or inadvertent activation of complement system contributes to the pathogenesis of some autoimmune diseases and cardiovascular diseases (CVD). Vascular calcification is the pivotal pathological basis of CVD, and contributes to the high morbidity and mortality of CVD. Increasing evidences indicate that the complement system plays a key role in chronic kidney diseases, atherosclerosis, diabetes mellitus and aging-related diseases, which are closely related with vascular calcification. However, the effect of complement system on vascular calcification is still unclear. In this review, we summarize current evidences about the activation of complement system in vascular calcification. We also describe the complex network of complement system and vascular smooth muscle cells osteogenic transdifferentiation, systemic inflammation, endoplasmic reticulum stress, extracellular matrix remodelling, oxidative stress, apoptosis in vascular calcification. Hence, providing a better understanding of the potential relationship between complement system and vascular calcification, so as to provide a direction for slowing the progression of this burgeoning health concern.

Effects of cerium oxide (CeO2) on liver tissue in liver ischemia-reperfusion injury in rats undergoing desflurane anesthesia

INTRODUCTION

During liver surgery and transplantation, periods of partial or total vascular occlusion are inevitable and result in ischemia-reperfusion injury (IRI). Nanomedicine uses the latest technology, which has emerged with interdisciplinary effects, such as biomedical sciences, physics, and engineering, to protect and improve human health. Interdisciplinary research has brought along the introduction of antioxidant nanoparticles as potential therapeutics. The goal of this study was to investigate the effects of cerium oxide (CeO₂) administration and desflurane anesthesia on liver tissue in liver IR injury.

MATERIAL AND METHODS

Thirty rats were randomly divided into five groups: control (C), ischemia-reperfusion (IR), IR-desflurane (IRD), cerium oxide-ischemia reperfusion (CeO₂-IR), and cerium oxide-ischemia reperfusion-desflurane (CeO₂-IRD). In the IR, IRD, and CeO₂-IRD groups, hepatic ischemia was induced after the porta hepatis was clamped for 120 min, followed by 120 min of reperfusion. Intraperitoneal 0.5 mg/kg CeO₂ was administered to the CeO₂ groups 30 min before ischemia. Desflurane (6%) was administered to the IRD and CeO₂-IRD groups during IR. All groups were sacrificed under anesthesia. Liver tissue samples were examined under a light microscope by staining with hematoxylin-eosin (H&E). Malondialdehyde (MDA) levels, catalase (CAT), glutathione-s-transferase (GST), and arylesterase (ARE) enzyme activities were measured in the tissue samples.

RESULTS

The IR group had considerably more hydropic degeneration, sinusoidal dilatation, and parenchymal mononuclear cell infiltration than the IRD, CeO₂-IR, and CeO₂-IRD groups. Catalase and GST enzyme activity were significantly higher in the CeO₂-IR group than in the IR group. The MDA levels were found to be significantly lower in the IRD, CeO₂-IR, and CeO₂-IRD groups than in the IR group.

CONCLUSION

Intraperitoneal CeO₂ with desflurane reduced oxidative stress and corrected liver damage.

Complement-targeting therapeutics for ischemia-reperfusion injury in transplantation and the potential for ex vivo delivery

Organ shortages and an expanding waitlist have led to increased utilization of marginal organs. All donor organs are subject to varying degrees of IRI during the transplant process. Extended criteria organs, including those from older donors and organs donated after circulatory death are especially vulnerable to ischemia-reperfusion injury (IRI). Involvement of the complement cascade in mediating IRI has been studied extensively. Complement plays a vital role in the propagation of IRI and subsequent recruitment of the adaptive immune elements. Complement inhibition at various points of the pathway has been shown to mitigate IRI and minimize future immune-mediated injury in preclinical models. The recent introduction of ex vivo machine perfusion platforms provides an ideal window for therapeutic interventions. Here we review the role of complement in IRI by organ system and highlight potential therapeutic targets for intervention during ex vivo machine preservation of donor organs.

Inhibition of macrophage migration inhibitory factor (MIF) suppresses apoptosis signal-regulating kinase 1 to protect against liver ischemia/reperfusion injury

Background: Hepatic ischemia–reperfusion (I/R) injury is a major complication leading to surgical failures in liver resection, transplantation, and hemorrhagic shock. The role of cytokine macrophage migration inhibitory factor (MIF) in hepatic I/R injury is unclear.

Methods: We examined changes of MIF expression in mice after hepatic I/R surgery and hepatocytes challenged with hypoxia–reoxygenation (H/R) insult. Subsequently, MIF global knock-out mice and mice with adeno-associated-virus (AAV)-delivered MIF overexpression were subjected to hepatic I/R injury. Hepatic histology, the inflammatory response, apoptosis and oxidative stress were monitored to assess liver damage. The molecular mechanisms of MIF function were explored in vivo and in vitro.

Results: MIF was significantly upregulated in the serum whereas decreased in liver tissues of mice after hepatic I/R injury. MIF knock-out effectively attenuated I/R -induced liver inflammation, apoptosis and oxidative stress in vivo and in vitro, whereas MIF overexpression significantly aggravated liver injury. Via RNA-seq analysis, we found a significant decreased trend of MAPK pathway in MIF knock-out mice subjected hepatic I/R surgery. Using the apoptosis signal-regulating kinase 1 (ASK1) inhibitor NQDI-1 we determined that, mechanistically, the protective effect of MIF deficiency on hepatic I/R injury was dependent on the suppressing of the ASK1-JNK/P38 signaling pathway. Moreover, we found MIF inhibitor ISO-1 alleviate hepatic I/R injury in mice.

Conclusion: Our results confirm that MIF deficiency suppresses the ASK1-JNK/P38 pathway and protects the liver from I/R -induced injury. Our findings suggest MIF as a novel biomarker and therapeutic target for the diagnosis and treatment of hepatic I/R injury.

Application of aptamers in regenerative medicine

Regenerative medicine is a discipline that studies how to use biological and engineering principles and operation methods to repair and regenerate damaged tissues and organs. Until now, regenerative medicine has focused mainly on the in-depth study of the pathological mechanism of diseases, the further development and application of new drugs, and tissue engineering technology strategies. The emergence of aptamers has supplemented the development methods and types of new drugs and enriched the application elements of tissue engineering technology, injecting new vitality into regenerative medicine. The role and application status of aptamers screened in recent years in various tissue regeneration and repair are reviewed, and the prospects and challenges of aptamer technology are discussed, providing a basis for the design and application of aptamers in long-term transformation.

Preclinical validation of silibinin/albumin nanoparticles as an applicable system against acute liver injury

BACKGROUND

Silibinin (SIL) has been extensively studied for its therapeutic effects on various liver diseases. However, its effect on acute liver injury was limited for poor solubility and low bioavailability. Thus, we prepared SIL and bovine serum albumin (SIL/BSA) nanoparticles and further evaluated their therapeutic efficacy against acute liver injury in mouse models.

METHODS

SIL/BSA nanoparticles were prepared via a nanoprecipitation method. Both in vitro cell culture model and in vivo mouse models of acetaminophen (APAP) and lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver injury were used to evaluate the therapeutic effect of SIL/BSA nanoparticles and potential mechanisms.

RESULTS

The SIL/BSA nanoparticles with hydrophilic diameters of 90 ± 29 nm were stably suspended. SIL/BSA nanoparticles presented better biocompatibility and more liver distribution in vivo than SIL microparticles. SIL/BSA nanoparticles significantly alleviated APAP and LPS/D-GalN induced acute liver injury in mice. Similarly, SIL/BSA nanoparticles remarkably enhanced the viability of hepatocytes in vitro against both APAP and LPS/D-GalN induced hepatocyte damage. Moreover, SIL/BSA nanoparticles exhibited antioxidant effects against intracellular oxidative stress via upregulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant responsive element (ARE) pathway, decreasing ROS and regulating antioxidant enzyme reactivity. And the downstream of mitochondria damage and caspase 9/3 related apoptosis pathway was also inhibited CONCLUSION: SIL/BSA nanoparticles were successfully prepared to enhance the liver availability of SIL. Both in vivo and in vitro, SIL/BSA nanoparticles exerted ideal hepatoprotective and antioxidant efficacy against acute liver injury, suggesting the promising future in clinical transfer.

STATEMENT OF SIGNIFICANCE

In our study, we prepared small-size, stable and well-dispersed silibinin/bovine serum albumin (SIL/BSA) nanoparticles via using simple and cost-effective nanoprecipitation techniques. Their physicochemical and pharmacokinetic characteristics were analyzed. We systematically studied the hepatoprotective and antioxidant efficacy of SIL/BSA both in vivo and in vitro, using two acute liver injury models. These findings revealed that SIL/BSA nanoparticles exerted ideal hepatoprotective and antioxidant efficacy against acute liver injury, suggesting the promising future in clinical transfer.

Central nervous system injury meets nanoceria: opportunities and challenges

Central nervous system (CNS) injury, induced by ischemic/hemorrhagic or traumatic damage, is one of the most common causes of death and long-term disability worldwide. Reactive oxygen and nitrogen species (RONS) resulting in oxidative/nitrosative stress play a critical role in the pathological cascade of molecular events after CNS injury. Therefore, by targeting RONS, antioxidant therapies have been intensively explored in previous studies. However, traditional antioxidants have achieved limited success thus far, and the development of new antioxidants to achieve highly effective RONS modulation in CNS injury still remains a great challenge. With the rapid development of nanotechnology, novel nanomaterials provided promising opportunities to address this challenge. Within these, nanoceria has gained much attention due to its regenerative and excellent RONS elimination capability. To promote its practical application, it is important to know what has been done and what has yet to be done. This review aims to present the opportunities and challenges of nanoceria in treating CNS injury. The physicochemical properties of nanoceria and its interaction with RONS are described. The applications of nanoceria for stroke and neurotrauma treatment are summarized. The possible directions for future application of nanoceria in CNS injury treatment are proposed.

In vivo study of dose-dependent antioxidant efficacy of functionalized core-shell yttrium oxide nanoparticles

Abstract

Herein, we assess the dose-dependent antioxidant efficacy of ultrafine spherical functionalized core–shell yttrium oxide nanoparticles (YNPs) with a mean size of 7–8 nm and modified with poly EGMP (ethylene glycol methacrylate phosphate) and N-Fluorescein Acrylamide. The antioxidant properties of these nanoparticles were investigated in three groups of Sprague–Dawley rats (10 per group) exposed to environmental stress daily for 1 week and one control group. Groups 2 and 3 were intravenously injected twice a week with YNPs at 0.3 and 0.5 mg at 2nd and 5th day of environmental stress exposure respectively. Different samples of blood and serum were collected from all experimental groups at end of the experiment to measure oxidative biomarkers such as total antioxidant capacity (TAC), hydroxyl radical antioxidant capacity (HORAC), oxygen radical antioxidant capacity (ORAC), malondialdehyde (MDA), and oxidants concentration as hydrogen peroxide (H₂O₂). The liver, brain, and spleen tissues were collected for fluorescence imaging and histopathological examination in addition to brain tissue examination by transmission electron microscope (TEM). Inductively coupled plasma-mass spectrometry (ICP-MS) was used to estimate YNPs translocation and concentration in tissues which is consecutively dependent on the dose of administration. Depending on all results, poly EGMP YNPs (poly EGMP yttrium oxide nanoparticles) can act as a potent direct antioxidant in a dose-dependent manner with good permeability through blood–brain barrier (BBB). Also, the neuroprotective effect of YNPs opening the door to a new therapeutic approach for modulating oxidative stress–related neural disorders.

Highlights

• The dose-dependent antioxidant efficacy of ultrafine spherical functionalized core–shell yttrium oxide nanoparticles (YNPs) with a mean size of 7–8 nm and modified with poly EGMP (ethylene glycol methacrylate phosphate) and N-Fluorescein Acrylamide was assessed.

• The dose of administration directly affecting the brain, liver, and spleen tissues distribution, retention, and uptake of YNPs and direct correlation between the absorbed amount and higher dose administered.

• YNPs can act as a potent direct antioxidant in a dose-dependent manner with good permeability through blood–brain barrier (BBB).

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s00210-022-02219-1.

An antioxidant nanodrug protects against hepatic ischemia-reperfusion injury by attenuating oxidative stress and inflammation

Liver transplantation is currently recognized as the only effective therapeutic option for end-stage liver disease. Hepatic ischemia-reperfusion injury (IRI) remains a major cause of graft damage or dysfunction, and is mediated by the abundant production of reactive oxygen species (ROS) and a complex cascade of inflammation during the reperfusion period. However, no universal antioxidant has been applied in clinical practice due to its low bioavailability and non-specific targeting. Herein, cerium oxide and manganese oxide nanocomposites (CM NCs), with the advantages of high biocompatibility, passive liver-targeting and short-term metabolic excretion, were synthesized as a nanodrug for hepatic IRI therapy. The CM NCs exhibited excellent superoxide dismutase (SOD) and catalase (CAT) mimetic activity to scavenge ROS and generate oxygen (O₂). Therefore, CM NCs could alleviate oxidative stress, subsequently suppress the activation of Kupffer cells (KCs) and neutrophils, and reduce the secretion of inflammatory factors due to the synergistic effect of ROS scavenging and O₂ production. By exploring the underlying mechanisms of the CM NCs in the treatment of hepatic IRI, we suggest that the CM NCs with ROS scavenging and inflammation regulation capacity show clinical potential for hepatic IRI management and provide new perspectives in the treatment of other oxidative-stress-related diseases.