coupling [ 35 ] and the downregulation and upregulation of multiple genes, such as Trpc6 or Ryr2, involved in the activity of the sinoatrial node [ 36 ] have been previously reported in GK rats and could explain the impairment in myocardial function shown here. RSV had no effect on cardiac function prior to ischemic insult, as previously reported by Robich et al. [ 37 ]. However, 1 mg/kg/day of RSV decreased cardiac hypertrophy and improved the myocardial tolerance to ischemia-reperfusioninjury. Recently, Bagul et al. showed cardiac hypertrophy with increased cardiac cell size in rats under a high-fat diet, with a reverse effect of RSV administered in the food at 10 mg/kg/day for 8 weeks [ 19 ]. Lin et al. pointed out the decrease of atrial natriuretic peptide and TGF1β related to reduced infarct size in animals treated with RSV by intraperitoneal injection for 4 weeks [ 18 ]. RSV has also been shown to reduce pro-hypertrophic markers such as ANP, BNP, and β-MHC, and improve redox balance by increasing SOD [ 13 ] in streptozotocin (STZ) and high-fat model of type 2 diabetes. Interestingly, placebo treatment also showed a decrease in cardiac hypertrophy in type 2 diabetic rats. Placebo treatment (ethanol 1‰) may have an effect on cardiac hypertrophy, as suggested by Ninh et al. in a rodent model of pressure overload with cardiac hypertrophy [ 38 ]. Moreover, Miyamae et al. also showed a higher myocardial tolerance to ischemia-reperfusioninjury in animals treated with ethanol [ 39 ]. Nonetheless, the authors used up to 20% of ethanol in the drinking water, which might explain why we did not see an effect on the tolerance to ischemia-reperfusioninjury in our study.
Abstract. Diabetic cardiomyopathy, especially myocardial
ischemia reperfusion (I/R) injury, is a major cause of morbidity and mortality in type 2 diabetic patients. The increasing of basal p38 MAP Kinase (p38 MAPK) activation is a major factor that aggravates cardiac death on diabetic cardiomy- opathy. In addition, metformin also shows cardio-protective effects on myocardial ischemia/reperfusioninjury. In this study, we investigated the effect of the combination between metformin and p38 MAPK inhibitor (SB203580) in diabetic rats subjected to I/R injury. H9c2 cells were induced into a hyperglycemic condition and treated with metformin, SB203580 or the combination of metformin and SB203580. In addition, cells in both the presence and absence of drug treat- ment were subjected to simulated ischemia/reperfusioninjury. Cell viability and cellular reactive oxygen species (ROS) were determined. Moreover, the Goto-Kakizaki (GK) rats were treated with metformin, SB203580, and the combination of metformin and SB203580 for 4 weeks. Diabetic parameters and cardiac functions were assessed. Finally, rat hearts were induced ischemia/reperfusioninjury for the purpose of
This study also suggests that for the same amounts of total fats and saturated fats, the hearts of rats receiving n-3 PUFA were more resistant than those receiving increased amounts of n-6 PUFA. Although the difference was small, this may be of clinical relevance because high n-6 intake has been encouraged for many years in Western countries to replace saturated fats in the context of cholesterol-lowering diets  . Therefore, this study shows that the n-6-rich dietary strategy is not optimal in terms of myocardial resistance to ischemia-reperfusioninjury and CHD complications. This actually confirms previous clinical trials demonstrating no obvious beneficial effect of n-6 –rich cholesterol-lowering diets, although these were low in saturated fats . Thus, to decrease the risk of CHD complications, the optimal dietary strategy would be to decrease both saturated fats and n-6 PUFA and to increase n-3 PUFA, as also suggested by
We have previously demonstrated, in a rodent kidney ischemia-reperfusion model, that extensive renal tissue injury such as proximal tubule necrosis and outer medulla congestion occurred during the reperfusion phase following 60 min of ischemia . In these condi- tions, tissue remodelling is determined by the severity of ischemia as we have previously shown in a pig model of renal ischemia reperfusion . Tissular regeneration could be a pivotal key of organ outcome, limiting or counteracting injury development. Different markers of tissue remodelling or regeneration have been used in renal tissue such as vimentin, alpha-smooth muscle actin (a-SMA), proliferating cell nuclear antigen (PCNA) or translocator protein (TSPO) expressions. TSPO, formerly known as the peripheral-type benzodiazepine receptor , is a widely distributed transmembrane protein that is localized mainly in the outer mitochondrial membrane. Many functions are associated directly or indirectly with TSPO, including the regulation of cholesterol transport and steroid hormones synthesis, porphyrin transport and heme synthesis, apoptosis, cell proliferation, anion trans- port, regulation of mitochondrial functions and immuno- modulation [16,17]. TSPO expression has been shown to be modulated by renal ischemia-reperfusioninjury, in particular during the repair process [18,19]. Under these conditions, IRI could affect TSPO expression and sex hormone production respectively, modulating cellular response.
Ischemia/reperfusioninjury occurring during liver transplantation is mainly due to the generation of reactive oxygen species (ROS) upon revascularization. Thus, delivery of antioxidant enzymes might reduce the deleterious effects of ROS and improve liver graft initial function. Mangafodipir trisodium (MnDPDP), a contrast agent currently used in magnetic resonance imaging of the liver, has been shown to be endowed with powerful antioxidant properties. We hypothesized that MnDPDP could have a protective effect against liver ischemia reperfusioninjury when administrated to the donor prior to harvesting. Livers from Sprague Dawley rats pretreated or not with MnDPDP were harvested and subsequently preserved for 24 h in CelsiorH solution at 4uC. Organs were then perfused ex vivo for 120 min at 37uC with Krebs Henseleit solution. In MnDPDP (5 m mol/kg) group, we observed that ATP content was significantly higher at the end of the cold preservation period relative to untreated group. After reperfusion, livers from MnDPDP-treated rats showed better tissue integrity, less hepatocellular and endothelial cell injury. This was accompanied by larger amounts of bile production and higher ATP recovery as compared to untreated livers. The protective effect of MnDPDP was associated with a significant decrease of lipid peroxidation, mitochondrial damage, and apoptosis. Interestingly, MnDPDP-pretreated livers exhibited activation of Nfr2 and HIF-1a pathways resulting in a higher catalase and HO-1 activities. MnDPDP also increased total nitric oxide (NO) production which derived from higher expression of constitutive NO synthase and lower expression of inducible NO synthase. In conclusion, our results show that donor pretreatment with MnDPDP protects the rat liver graft from cold ischemia/reperfusioninjury and demonstrate for the first time the potential interest of this molecule in the field of organ preservation. Since MnDPDP is safely used in liver imaging, this preservation strategy holds great promise for translation to clinical liver transplantation.
Received: 24 April 2016; Accepted: 17 May 2016; Published: 25 May 2016
Abstract: The endoplasmic reticulum (ER) is involved in calcium homeostasis, protein folding and lipid biosynthesis. Perturbations in its normal functions lead to a condition called endoplasmic reticulum stress (ERS). This can be triggered by many physiopathological conditions such as alcoholic steatohepatitis, insulin resistance or ischemia-reperfusioninjury. The cell reacts to ERS by initiating a defensive process known as the unfolded protein response (UPR), which comprises cellular mechanisms for adaptation and the safeguarding of cell survival or, in cases of excessively severe stress, for the initiation of the cell death program. Recent experimental data suggest the involvement of ERS in ischemia/reperfusioninjury (IRI) of the liver graft, which has been considered as one of major problems influencing outcome after liver transplantation. The purpose of this review is to summarize updated data on the molecular mechanisms of ERS/UPR and the consequences of this pathology, focusing specifically on solid organ preservation and liver transplantation models. We will also discuss the potential role of ERS, beyond the simple adaptive response and the regulation of cell death, in the modification of cell functional properties and phenotypic changes.
ischemia and mostly reflow are well-known to induce high oxidative stress, which is exacerbated here by the 5-month high-fat high-sucrose diet. We also assessed the S- Glutathionylation of proteins, which is the reversible addition of glutathione to cysteine residues inactivating the target proteins , and which could be involved in CV complications . Protein S-Glutathionylation occurs mainly at the beginning of reflow in an ischemia-reperfusion protocol and has been shown to be increased in some studies. For example, De Pascali et al. showed an increase in eNOS S-Glutathionylation during ischemia- reperfusioninjury in endothelial cells . However, Belcastro et al. explained that S- Glutathionylation can also be a protective mechanism coping with irreversible oxidation . This would explain the lower rate of S-Glutathionylation found here in HFS vs. CTRL. We have shown that S-Glutathionylation of all the proteins was significantly decreased in HFS compared with CTRL, but we found no difference in specific S-Glutathionylation of eNOS. Here, we suggest that S-Glutathionylation was decreased by high-fat high-sucrose diet, leading to higher level of damage by oxidative stress in hearts. This result was consistent with the higher MDA heart content mentioned before.
Lidocaine is widely used as a local anesthetic, but has been recently administered systemically in horses to treat post operative ileus. It is known that local anesthetic agents modulate the inflammatory response via mechanisms unrelated to sodium channel blockade. Lidocaine has been shown to reduce cytokines release and inhibit neutrophil function. Additionally, in studies evaluating its effect on I/R injury in other organs, lidocaine has
6.1.4. The Effector MLKL
Mixed lineage kinase domain-like protein (MLKL) is a protein in the necroptotic signalling cascade, functioning downstream of RIPK3 [ 87 , 88 ]. The MLKL protein contains two domains: a N-terminal domain consisting of four helix bundles and a C-terminal pseudo-kinase domain [ 86 , 112 ]. This pseudo-kinase domain acts as a molecular switch that determines active or inactive MLKL configuration. Hence, its C-terminal interconnects with RIPK3 during necroptosis [ 87 ]. In contrast to RIPK3, which is functionally active, MLKL is related to a group of proteins that are enzymatically inactive, hence, termed pseudokinase [ 113 , 114 ]. When the phosphorylated RIPK3 propagates to form the necrosome, it recruits MLKL. Finally, upon activation, MLKL migrates to the plasma membrane which disintegrates releasing cellular contents and resulting in necroptotic cell death [ 115 , 116 ]. A study conducted by Wang et al. showed that necrotic cell death in drug-induced liver injury was due to the fact of MLKL activation [ 116 ]. In the context of inflammatory liver diseases, in both human samples and mouse models, MLKL activation is strongly correlated with hepatocellular necrosis [ 117 ]. Recent reports have also revealed a high expression of MLKL in human liver samples from patients with primary biliary cholangitis indicating activation of necroptosis. Similar results were seen in the murine model of BDL [ 100 ]. In other study, dermal fibroblast cells derived from Mlkl - /- mice, showed resistance to induced necroptosis [ 118 ]. The Fadd - /- Mlkl - /- double knockout mouse embryonic fibroblasts were resistant to TNFα plus zVAD-induced necroptosis [ 119 ]. The siRNA knockdown of MLKL in HT-29 cells ceased the progression of necrosis signalling [ 88 ].
why Aag-initiated BER is toxic and Ung/Ogg1/Neil1 initiated repair is not (34–36).
We previously observed that Aag −/− mice are more susceptible than WT mice to inflammation-associated colon cancer (12); this may at first appear to contradict the findings reported here. However, Aag-mediated cell death in the inflamed colon may serve to protect the colon against the accumulation of mutant cells, thus reducing carcinogenesis in the long term. This adap- tation may be beneficial because cell death rids the tissue of potentially mutated cells, albeit at the cost of an acute but tran- sient decline in tissue function. However, in disease models such as I/R-induced acute tissue injury and inflammation, extensive cell death may lead to tissue dysfunction or organ failure as demonstrated in this study. Additionally, though there are some similarities, it is likely that there are inherent differences between microbially induced chronic inflammation in the colon and acute sterile inflammation following I/R in the liver, brain, and kidney. Among the DNA base adducts measured, only 8-oxoG in- creased in Aag −/− liver DNA, with no significant change in e-DNA adducts. The low redox potential of guanine makes this base particularly vulnerable to oxidation (45), and 8-oxoG is readily generated during oxidative stress (46). Both Ogg1 and Aag can excise 8-oxoG, although Ogg1 is normally much more efficient (10, 47). However, it was recently shown that Ogg1 is a specific target of calpain I, a Ca 2+ -dependent protease acti- vated during oxidative stress (48); further, Ogg1 is directly inhibited by nitric oxide during inflammation (49). Thus, Aag mediated 8-oxoG excision may assume a very important role during conditions of oxidative tissue damage. Indeed, increased levels of 8-oxoG after I/R in Aag −/− livers underscores the sig- nificance of Aag-mediated 8-oxoG excision during I/R-induced injury. That Aag is important for 8-oxoG excision during in- flammation is further supported by our previous study in which Aag −/− mice accumulated higher levels of genomic 8-oxoG than
49. Sleiman, N.H.; McFarland, T.P.; Jones, L.R.; Cala, S.E. Transitions of protein traffic from cardiac ER to junctional SR. J. Mol. Cell. Cardiol. 2015, 81, 34–45, doi:10.1016/j.yjmcc.2014.12.025.
50. Hajnóczky, G.; Csordás, G.; Madesh, M.; Pacher, P. The machinery of local Ca 2+ signalling between sarco‐
endoplasmic reticulum and mitochondria. J. Physiol. 2000, 529, 69–81, doi:10.1111/j.1469‐7793.2000.00069.x. 51. Bochaton, T.; Crola‐Da‐Silva, C.; Pillot, B.; Villedieu, C.; Ferreras, L.; Alam, M.R.; Thibault, H.; Strina, M.; Gharib, A.; Ovize, M.; et al. Inhibition of myocardial reperfusioninjury by ischemic postconditioning requires sirtuin 3‐mediated deacetylation of cyclophilin D. J. Mol. Cell. Cardiol. 2015, 84, 61–69, doi:10.1016/j.yjmcc.2015.03.017.
Transplantation Rénale, CHU de Poitiers, Poitiers, France, 4 Service d’Immunologie et d’Inflammation, CHU de Poitiers,
Although the contribution of iNKT cells to induction of sterile inflammation is now well-established, the nature of the endogenous compounds released early after cellular stress or damage that drive their activation and recruitment remains poorly understood. More precisely, iNKT cells have not been described as being reactive to endogenous non-protein damage-associated molecular-pattern molecules (DAMPs). A second subset of DAMPs, called alarmins, are tissue-derived nuclear proteins, constitutively expressed at high levels in epithelial barrier tissues and endothelial barriers. These potent immunostimulants, immediately released after tissue damage, include the alarmin IL-33. This factor has aroused interest due to its singular action as an alarmin during infectious, allergic responses and acute tissue injury, and as a cytokine, contributing to the latter resolutive/repair phase of sterile inflammation. IL-33 targets iNKT cells, inducing their recruitment in an inflammatory state, and amplifying their regulatory and effector functions. In the present review, we introduce the new concept of a biological axis of iNKT cells and IL-33, involved in alerting and controlling the immune cells in experimental models of sterile inflammation. This review will focus on acute organ injury models, especially ischemia-reperfusioninjury, in the kidneys, liver and lungs, where iNKT cells and IL-33 have been presumed to mediate and/or control the injury mechanisms, and their potential relevance in human pathophysiology.
Pierre SV, Belliard A, Sottejeau Y. Modulation of Na ⫹ -K ⫹ - ATPase cell surface abundance through structural determinants on the ␣1-subunit. Am J Physiol Cell Physiol 300: C42–C48, 2011. First published November 3, 2010; doi:10.1152/ajpcell.00386.2010.— Through their ion-pumping and non-ion-pumping functions, Na ⫹ - K ⫹ -ATPase protein complexes at the plasma membrane are critical to intracellular homeostasis and to the physiological and pharmacolog- ical actions of cardiotonic steroids. Alteration of the abundance of Na ⫹ -K ⫹ -ATPase units at the cell surface is one of the mechanisms for Na ⫹ -K ⫹ -ATPase regulation in health and diseases that has been closely examined over the past few decades. We here summarize these ﬁndings, with emphasis on studies that explicitly tested the involve- ment of deﬁned regions or residues on the Na ⫹ -K ⫹ -ATPase ␣1 polypeptide. We also report new ﬁndings on the effect of manipulat- ing Na ⫹ -K ⫹ -ATPase membrane abundance by targeting one of these deﬁned regions: a dileucine motif of the form [D/E]XXXL[L/I]. In this study, opossum kidney cells stably expressing rat ␣1 Na ⫹ -K ⫹ - ATPase or a mutant where the motif was disrupted ( ␣1-L499V) were exposed to 30 min of substrate/coverslip-induced-ischemia followed by reperfusion (I-R). Biotinylation studies suggested that I-R itself acted as an inducer of Na ⫹ -K ⫹ -ATPase internalization and that surface expression of the mutant was higher than the native Na ⫹ -K ⫹ - ATPase before and after ischemia. Annexin V/propidium iodide staining and lactate dehydrogenase release suggested that I-R injury was reduced in ␣1-L499V-expressing cells compared with ␣1-ex- pressing cells. Hence, modulation of Na ⫹ -K ⫹ -ATPase cell surface abundance through structural determinants on the ␣-subunit is an important mechanism of regulation of cellular Na ⫹ -K ⫹ -ATPase in various physiological and pathophysiological conditions, with a sig- niﬁcant impact on cell survival in face of an ischemic stress. dileucine motif; ischemia-reperfusioninjury; oppossum kidney cells; cardiotonic steroids
reperfusate was rendered markedly alkalotic with a buffer to reverse tissue acidosis, despite the low flow of the reperfusate. As shown by the arteriovenous difference in P O 2 (Table II), oxygen uptake was not affected by the increased pH of the reperfusate. Amino acids are released by the skeletal muscle after ischemia, and glutamate uptake is related to arterial plasma levels. 4,5,10 Thus the reperfusate was enriched in glutamate and aspartate, which, as in the cardiac muscle, are used in the Krebs cycle to produce adenosine triphosphate for cell repair and subsequent function. Finally, the high levels of systemic heparinization used in controlled reperfusion might avoid propagation of thrombus in both the arterial and venous circulation. 4,5 The prevention of oxygen free radical production with a xanthine oxidase inhibitor (i.e. allopurinol) may be useful. However, reperfusioninjury has a complex pathophysiologic basis and cannot be used as a synonym for free radical injury because a
Ischemia reperfusion control: the key of kidney graft outcome During the transplantation procedure, ischemia reperfusion is an inevi- table situation characterized by specific pathophysiological processes, which ultimately act synergistically to create injuries in the graft. These injuries are involved in early graft dysfunctions which promote chronic dysfunction and compromise graft outcome. Progresses in immunosup- pressive drug regimens now place ischemia reperfusioninjury control at the forefont for innovative therapeutic strategy to improve the quality of the graft. This review details these different processes and its consequences on renal graft function underlying the interest of novel therapeutic strategy. ‡
In rat kidneys, mRNA abundance of DPP-4 was significantly decreased following I/R in all group: NR (2,07-fold), 6h (8,12-fold), 24h (12.5-fold) and 48h (12.9-fold). Immunoblotting analyses showed a 1.2-fold reduction of DPP-4 expression in the NR group, a 2.14-fold in the 6H group and a 2.3-fold at both 24h and 48h post reperfusion (Fig.1). In human kidneys with ATN, the abundance of DPP-4 appeared reduced in comparison to healthy controls. Still, we did not observe evidence of DPP-4 internalization into PT cells.