Ischemia/reperfusion: a clinically relevant model of intestinal injury yielding systemic inflammation

Biomimetic Lung-Targeting Nanoparticles with Antioxidative and Nrf2 Activating Properties for Treating Ischemia/Reperfusion-Induced Acute Lung Injury

Ischemia/reperfusion (IR)-induced acute lung injury (ALI) has a high mortality rate. Reactive oxygen species (ROS) play a crucial role in causing cellular damage and death in IR-induced ALI. In this work, we developed a biomimetic lung-targeting nanoparticle (PC@MB) as an antioxidative lung protector for treating IR-induced ALI. PC@MBs showed excellent ROS scavenging and Nrf2 activation properties, along with a lung-targeting function through autologous cell membrane coating. The PC@MBs exhibited an impressive antioxidative and pulmonary protective role via redox homeostasis recovery through Nrf2 and heme oxygenase-1 activation. PC@MBs could maintain cell viability by effectively scavenging the intracellular ROS and restoring the redox equilibrium in the lesion. In the IR mouse model, the PC@MBs preferentially accumulated in the lung and distinctly repaired the pneumonic damage. Our strategy has the potential to offer a promising therapeutic paradigm for treating IR-induced ALI through the incorporation of different therapeutic mechanisms.

E3 ligase TRIM65 alleviates intestinal ischemia/reperfusion injury through inhibition of TOX4-mediated apoptosis

Intestinal ischemia-reperfusion (II/R) injury is an urgent clinical disease with high incidence and mortality, and impaired intestinal barrier function caused by excessive apoptosis of intestinal cells is an important cause of its serious consequences. Tripartite motif-containing protein 65 (TRIM65) is an E3 ubiquitin ligase that is recently reported to suppress the inflammatory response and apoptosis. However, the biological function and regulation of TRIM65 in II/R injury are totally unknown. We found that TRIM65 was significantly decreased in hypoxia-reoxygenation (H/R) induced intestinal epithelial cells and II/R-induced intestine tissue. TRIM65 knockout mice markedly aggravated intestinal apoptosis and II/R injury. To explore the molecular mechanism of TRIM65 in exacerbating II/R-induced intestinal apoptosis and damage, thymocyte selection-associated high mobility group box factor 4 (TOX4) was screened out as a novel substrate of TRIM65 using the yeast two-hybrid system. TRIM65 binds directly to the N-terminal of TOX4 through its coiled-coil and SPRY structural domains. Immunofluorescence confocal microscopy showed that they can co-localize both in the cytoplasm and nucleus. Furthermore, TRIM65 mediated the K48 ubiquitination and degradation of TOX4 depending on its E3 ubiquitin ligase activity. In addition, TRIM65 inhibits H/R-induced intestinal epithelial apoptosis via TOX4. In summary, our results indicated that TRIM65 promotes ubiquitination and degradation of TOX4 to inhibit apoptosis in II/R. These findings provide a promising target for the clinical treatment of II/R injury.

The Effect of Antioxidant Astaxanthin on Intestinal Ischemia Reperfusion Damage in Rats

BACKGROUND

Mesenteric ischemia is a frequently encountered disease in surgical clinics, difficult to diagnose, and very mortal if not treated. Our study investigated the effects of astaxanthin, which is known to have potent antioxidant properties and is also known to have anti-inflammatory effects on ischemia-reperfusion (I/R) injury.

METHODS

A total of 32 healthy Wistar albino female rats were used in our study. Subjects were randomized and equally divided into 4 groups; control (laparotomy group only), I/R (transient mesenteric ischemia group only), astaxanthin 1 mg/kg and 10 mg/kg doses. The transient ischemia time was 60 minutes and the reperfusion time was 120 minutes. Tissue samples were taken from intracardiac blood and terminal ileum after reperfusion. Superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) from blood samples, interleukin-1 (IL-1), IL-6, tumor necrosis factor-α (TNFα), Caspase-3, P53 tests from terminal ileum were studied. Tissue samples were also taken for histopathological evaluation.

RESULTS

At the end of the study, both doses of astaxanthin were found to significantly reduce MDA level, CAT, and SOD enzymatic activity, whereas higher doses of astaxanthin significantly reduced MDA level, CAT, and SOD enzyme activities. In addition, cytokines such as TNFα, IL-1 and IL-6 were found to be reduced at both doses of astaxanthin, but only significantly inhibited at higher doses. We observed that inhibition of apoptosis reduced caspase-3 activity and P53 and deoxyribonucleic acid (DNA) fragmentation.

CONCLUSION

Astaxanthin, a potent antioxidant, and anti-inflammatory, significantly reduces ischemia and reperfusion injury, especially when used at a dose of 10 mg/kg. These data need to be confirmed by larger animal series and clinical studies.

H151, A SMALL MOLECULE INHIBITOR OF STING AS A NOVEL THERAPEUTIC IN INTESTINAL ISCHEMIA-REPERFUSION INJURY

BACKGROUND

Intestinal ischemia-reperfusion (I/R) injury is a severe disease associated with high mortality. Stimulator of interferon genes (STING) is an intracellular protein that is activated by cytosolic DNA and is implicated in I/R injury, resulting in transcription of type I interferons (IFN-α and IFN-β) and other proinflammatory molecules. Extracellular cold-inducible RNA-binding protein (eCIRP), a damage-associated molecular pattern, induces STING activation. H151 is a small molecule inhibitor of STING that has not yet been studied as a potential therapeutic. We hypothesize that H151 reduces inflammation, tissue injury, and mortality after intestinal I/R. Methods: In vitro, RAW264.7 cells were pretreated with H151 then stimulated with recombinant murine (rm) CIRP, and IFN-β levels in the culture supernatant were measured at 24 hours after stimulation. In vivo, male C57BL/6 mice were subjected to 60-minute intestinal ischemia via superior mesenteric artery occlusion. At the time of reperfusion, mice were intraperitoneally instilled with H151 (10 mg/kg BW) or 10% Tween-80 in PBS (vehicle). Four hours after reperfusion, the small intestines, lungs, and serum were collected for analysis. Mice were monitored for 24 hours after intestinal I/R to assess survival. Results: In vitro, H151 reduced rmCIRP-induced IFN-β levels in a dose-dependent manner. In vivo, intestinal levels of pIRF3 were increased after intestinal I/R and decreased after H151 treatment. There was an increase in serum levels of tissue injury markers (lactate dehydrogenase, aspartate aminotransferase) and cytokine levels (interleukin 1β, interleukin 6) after intestinal I/R, and these levels were decreased after H151 treatment. Ischemia-reperfusion-induced intestinal and lung injury and inflammation were significantly reduced after H151 treatment, as evaluated by histopathologic assessment, measurement of cell death, chemokine expression, neutrophil infiltration, and myeloperoxidase activity. Finally, H151 improved the survival rate from 41% to 81% after intestinal I/R. Conclusions: H151, a novel STING inhibitor, attenuates the inflammatory response and reduces tissue injury and mortality in a murine model of intestinal I/R. H151 shows promise as a potential therapeutic in the treatment of this disease.

Anisodamine hydrobromide ameliorates cardiac damage after resuscitation

The microcirculation is correlated with the prognosis of patients with cardiac arrest and changes after resuscitation. In the present study, the effects of anisodamine hydrobromide (AH) on microcirculation was investigated and its potential mechanisms were explored. A total of 24 pigs were randomly grouped into three groups (n=8): Sham, Saline and AH group. After pigs were anesthetized, intubated and mechanically ventilated, ventricular fibrillation was induced by electrical stimulation. After 8 min, cardiopulmonary resuscitation was given to the restoration of spontaneous circulation (ROSC). Arteriovenous blood was collected at baseline and 0, 1, 2, 4 and 6 h after ROSC to measure blood gas and cytokines. Perfused vessel density (PVD) and microvascular flow index (MFI) were measured to reflect the microcirculation. Continuous cardiac output and global ejection fraction were measured to indicate hemodynamics. Compared with Sham group, PVD and MFI in the intestines and the sublingual regions decreased significantly after resuscitation. The microcirculation recovered faster in the AH group than the SA group. The decrease of intestinal microcirculatory blood flow was closely related to the decrease of sublingual microcirculatory blood flow. The cardiac function was impaired after resuscitation, and a decrease of IFN-γ as well as IL-2 and an increase of IL-4 as well as IL-10 suggested the immune imbalance. The microcirculation changes in sublingual regions were closely related to the changes in intestines. AH could improve the immune imbalance after resuscitation and was beneficial to the recovery of cardiac function.

Mitochondrial DNA Release Contributes to Intestinal Ischemia/Reperfusion Injury

Mitochondria release many damage-associated molecular patterns (DAMPs) when cells are damaged or stressed, with mitochondrial DNA (mtDNA) being. MtDNA activates innate immune responses and induces inflammation through the TLR-9, NLRP3 inflammasome, and cGAS-STING signaling pathways. Released inflammatory factors cause damage to intestinal barrier function. Many bacteria and endotoxins migrate to the circulatory system and lymphatic system, leading to systemic inflammatory response syndrome (SIRS) and even damaging the function of multiple organs throughout the body. This process may ultimately lead to multiple organ dysfunction syndrome (MODS). Recent studies have shown that various factors, such as the release of mtDNA and the massive infiltration of inflammatory factors, can cause intestinal ischemia/reperfusion (I/R) injury. This destroys intestinal barrier function, induces an inflammatory storm, leads to SIRS, increases the vulnerability of organs, and develops into MODS. Mitophagy eliminates dysfunctional mitochondria to maintain cellular homeostasis. This review discusses mtDNA release during the pathogenesis of intestinal I/R and summarizes methods for the prevention or treatment of intestinal I/R. We also discuss the effects of inflammation and increased intestinal barrier permeability on drugs.

Targeting Ferroptosis: Pathological Mechanism and Treatment of Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) is a pathological process that occurs in many organs and diseases. Reperfusion, recovery of blood flow, and reoxygenation often lead to reperfusion injury. Drug therapy and early reperfusion therapy can reduce tissue injury and cell necrosis caused by ischemia, leading to irreversible I/R injury. Ferroptosis was clearly defined in 2012 as a newly discovered iron-dependent, peroxide-driven, nonapoptotic form of regulated cell death. Ferroptosis is considered the cause of reperfusion injury. This discovery provides new avenues for the recognition and treatment of diseases. Ferroptosis is a key factor that leads to I/R injury and organ failure. Given the important role of ferroptosis in I/R injury, there is considerable interest in the potential role of ferroptosis as a targeted treatment for a wide range of I/R injury-related diseases. Recently, substantial progress has been made in applying ferroptosis to I/R injury in various organs and diseases. The development of ferroptosis regulators is expected to provide new opportunities for the treatment of I/R injury. Herein, we analytically review the pathological mechanism and targeted treatment of ferroptosis in I/R and related diseases from the perspectives of myocardial I/R injury, cerebral I/R injury, and ischemic renal injury.

Nrf2 attenuates ferroptosis-mediated IIR-ALI by modulating TERT and SLC7A11

Acute lung injury (ALI) carries a mortality rate of ~50% and is a hot topic in the world of critical illness research. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a critical modulator of intracellular oxidative homeostasis and serves as an antioxidant. The Nrf2-related anti-oxidative stress is strongly associated with ferroptosis suppression. Meanwhile, telomerase reverse transcriptase (TERT), the catalytic portion of the telomerase protein, is reported to travel to the mitochondria to alleviate ROS. In our study, we found that TERT was significantly reduced in lung tissue of Nrf2^-/- mice in the model of intestinal ischemia/reperfusion-induced acute lung injury (IIR-ALI). In addition, MDA levels showed marked increase, whereas GSH and GPX4 levels fell drastically in ALI models. Moreover, typical-related structural changes were observed in the type II alveolar epithelial cells in the IIR model. We further employed the scanning transmission X-ray microscopy (STXM) to examine Fe levels and distribution within cells. Based on our observations, massive aggregates of Fe were found in the MLE-12 cells upon OGD/R (oxygen and glucose deprivation/reperfusion) induction. Additionally, Nrf2 silencing dramatically reduced TERT and SLC7A11 levels, and further exacerbated cellular injuries. In contrast, TERT-overexpressing cells exhibited marked elevation in SLC7A11 levels and thereby inhibited ferroptosis. Collectively, these data suggest that Nrf2 can negatively regulate ferroptosis via modulation of TERT and SLC7A11 levels. The conclusion from this study brings insight into new candidates that can be targeted in future IIR-ALI therapy.

Therapeutic Potential of B-1a Cells in Intestinal Ischemia-reperfusion Injury

BACKGROUND

Acute mesenteric ischemia is a common surgical emergency. Restoration of blood flow is a critical objective of treating this pathology. However, many patients suffer from ischemia-reperfusion (I/R) injuries at the time of revascularization, requiring prolonged hospitalizations. B-1a cells are a subtype of B lymphocytes with roles in regulating inflammation and tissue injury by spontaneous release of natural IgM and IL-10. We hypothesized that treatment with B-1a cells protects mice from intestinal I/R.

METHODS

Mesenteric ischemia was induced in mice by placing a vascular clip on the superior mesenteric artery for 60 minutes. At the time of reperfusion, B-1a cells or PBS control were instilled into the peritoneal cavity (PerC) of mice. PerC lavage, blood, intestine, and lungs were collected 4 h after reperfusion. Serum organ injury and inflammatory markers such as ALT, AST, LDH, lactate, IL-6, as well as lung and gut histology and myeloperoxidase (MPO) were assessed.

RESULTS

In intestinal I/R, B-1a cell frequency and number in the PerC were significantly decreased compared to sham-operated mice. There was an increase in the serum levels of ALT, AST, LDH, lactate, and IL-6 when comparing the vehicle group with the sham group. These increases were significantly reduced in the B-1a cell treated group. B-1a cell treatment significantly decreased the intestine and lung injury scores as well as MPO content, compared to vehicle treated mice. B-1a cell treatment resulted in a reduction of apoptotic cells in these tissues. Serum IgM levels were decreased in intestinal I/R, while treatment with B-1a cells significantly increased their levels towards normal levels.

CONCLUSIONS

B-1a cell treatment at the time of mesenteric reperfusion ameliorates end organ damage and reduces systemic inflammation through the improvement of serum IgM levels. Preserving B-1a cells pool could serve as a novel therapeutic avenue in intestinal I/R injury.

Cellular Signal Transduction Pathways Involved in Acute Lung Injury Induced by Intestinal Ischemia-Reperfusion

Intestinal ischemia-reperfusion (II/R) injury is a common type of tissue and organ injury, secondary to intestinal and mesenteric vascular diseases. II/R is characterized by a high incidence rate and mortality. In the II/R process, intestinal barrier function is impaired and bacterial translocation leads to excessive reactive oxygen species, inflammatory cytokine release, and even apoptosis. A large number of inflammatory mediators and oxidative factors are released into the circulation, leading to severe systemic inflammation and multiple organ failure of the lung, liver, and kidney. Acute lung injury (ALI) is the most common complication, which gradually develops into acute respiratory distress syndrome and is the main cause of its high mortality. This review summarizes the signal transduction pathways and key molecules in the pathophysiological process of ALI induced by II/R injury and provides a new therapeutic basis for further exploration of the molecular mechanisms of ALI induced by II/R injury. In particular, this article will focus on the biomarkers involved in II/R-induced ALI.

Nrf2 inhibits ferroptosis and protects against acute lung injury due to intestinal ischemia reperfusion via regulating SLC7A11 and HO-1

Acute lung injury (ALI) is a syndrome associated with a high mortality rate. Nrf2 is a key regulator of intracellular oxidation homeostasis that plays a pivotal role in controlling lipid peroxidation, which is closely related to the process of ferroptosis. However, the intrinsic effect of Nrf2 on ferroptosis remains to be investigated in ALI. We found that MDA expression increased while GSH and GPX4 decreased in ALI models. Furthermore, the characteristic mitochondrial morphological changes of ferroptosis appear in type II alveolar epithelial cells in IIR models. Additional pre-treatment of Fe and Ferrostatin-1 in ALI significantly aggravated or ameliorated the pathological injuries of lung tissue, pulmonary edema, lipid peroxidation, as well as promoted or prevented cell death, respectively. Knocking down Nrf2 notably decreased the expression of SLC7A11 and HO-1. Interference with SLC7A11 markedly increased Nrf2-HO-1 and dramatically attenuated cell death in OGD/R models. These findings indicate that ferroptosis can be inhibited by Nrf2 through regulating SLC7A11 and HO-1, which may provide a potential therapeutic strategy for IIR-ALI.

Inhibition of a triggering receptor expressed on myeloid cells-1 (TREM-1) with an extracellular cold-inducible RNA-binding protein (eCIRP)-derived peptide protects mice from intestinal ischemia-reperfusion injury

BACKGROUND

Intestinal ischemia-reperfusion injury results in morbidity and mortality from both local injury and systemic inflammation and acute lung injury. Extracellular cold-inducible RNA-binding protein is a damage associated molecular pattern that fuels systemic inflammation and potentiates acute lung injury. We recently discovered a triggering receptor expressed on myeloid cells-1 serves as a novel receptor for extracellular cold-inducible RNA-binding protein. We developed a 7-aa peptide, named M3, derived from the cold-inducible RNA-binding protein, which interferes with cold-inducible RNA-binding protein's binding to a triggering receptor expressed on myeloid cells-1. Here, we hypothesized that M3 protects mice against intestinal ischemia-reperfusion injury.

METHODS

Intestinal ischemia was induced in C57BL/6 mice via clamping of the superior mesenteric artery for 60 minutes. At reperfusion, mice were treated intraperitoneally with M3 (10 mg/kg body weight) or normal saline vehicle. Mice were killed 4 hours after reperfusion and blood and lungs were collected for various analysis. A 24-hours survival after intestinal ischemia-reperfusion was assessed.

RESULTS

Serum levels of organ injury markers aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and lactate were increased with intestinal ischemia-reperfusion, while treatment with M3 significantly decreased their levels. Serum, intestinal, and lung levels of proinflammatory cytokines and chemokines were also increased by intestinal ischemia-reperfusion, and treatment with M3 significantly reduced these values. Intestinal ischemia-reperfusion caused significant histological intestinal and lung injuries, which were mitigated by M3. Treatment with M3 improved the survival from 40% to 80% after intestinal ischemia-reperfusion.

CONCLUSION

Inhibition of triggering receptor expressed on myeloid cells-1 by an extracellular cold-inducible RNA-binding protein-derived small peptide (M3) decreased inflammation, reduced lung injury, and improved survival in intestinal ischemia-reperfusion injury. Thus, blocking the extracellular cold-inducible RNA-binding protein-triggering receptor expressed on myeloid cells-1 interaction is a promising therapeutic avenue for mitigating intestinal ischemia-reperfusion injury.

Effect of ulinastatin combined with mild therapeutic hypothermia on intestinal barrier dysfunction following cardiopulmonary resuscitation in rats

The aim of the present study was to investigate the effect of ulinastatin (UTI) alone or combined with mild therapeutic hypothermia (MTH) on intestinal barrier dysfunction following cardiopulmonary resuscitation (CPR) in rats. A total of 25 adult male Sprague-Dawley rats were randomly organized into five groups: Sham; control; UTI; MTH; and the combined group. The latter four groups were induced with the asphyxiated cardiac arrest rat model and treated with different interventions. After 6 h of treatment, the intestinal tissues of the rats were examined by electron microscopy, and the levels of intestinal malondialdehyde (MDA) and superoxide dismutase (SOD) were determined. The results of the present study indicated that the target temperature had successfully been attained in MTH and the combined group, and the other three groups of rats all survived at a normal temperature. In the rats treated with UTI or MTH, the epithelial cells exhibited pathological changes in their tight junctions and epithelial cell surface microvilli compared with the sham group. In the rats treated with a combination of UTI and MTH, whilst the epithelial cells exhibited a few slight changes, including mitochondrial edema, they were largely similar to the normal epithelial cells. However, there were significant differences in the levels of MDA and SOD between the different treatment groups. UTI combined with MTH may serve a protective role by suppressing oxidative stress in the small intestinal mucosa following CPR in rats compared with either UTI or MTH treatment alone.

Cold-inducible RNA-binding protein-derived peptide C23 attenuates inflammation and tissue injury in a murine model of intestinal ischemia-reperfusion

BACKGROUND

Cold-inducible RNA-binding protein is a novel damage-associated molecular pattern that causes inflammation. C23, a short peptide derived from cold-inducible RNA-binding protein, has been found to have efficacy in blocking cold-inducible RNA-binding protein's activity. We hypothesized that C23 reduces inflammation and tissue injury induced by intestinal ischemia-reperfusion.

METHODS

Male C57BL/6 mice were subjected to 60 minutes of intestinal ischemia by clamping the superior mesenteric artery. Immediately after reperfusion, either normal saline (vehicle) or C23 peptide (8 mg/kg body weight) was injected intraperitoneally. Four hours after reperfusion, blood, intestinal, and lung tissues were collected for analysis of inflammatory and tissue injury parameters.

RESULTS

Cold-inducible RNA-binding protein levels in the intestinal tissues were significantly increased following intestinal ischemia-reperfusion. Histologic examination of the intestine revealed a significant reduction in injury score in the C23 group by 48% as compared with the vehicles after intestinal ischemia-reperfusion. The serum levels of lactate dehydrogenase and aspartate aminotransferase were increased in animals that underwent vehicle-treated intestinal ischemia-reperfusion, whereas C23-treated animals exhibited significant reductions by 48% and 53%, respectively. The serum and intestinal tissue levels of tumor necrosis factor α were elevated in vehicle-treated intestinal ischemia-reperfusion mice but decreased by 72% and 69%, respectively, in C23-treated mice. Interleukin-6 mRNA levels in the lungs were reduced by 86% in the C23-treated group in comparison to the vehicle-treated group after intestinal ischemia-reperfusion. Expression of macrophage inflammatory protein 2 and level of myeloperoxidase activity in the lungs were dramatically increased after intestinal ischemia-reperfusion and significantly reduced by 91% and 25%, respectively, in the C23-treated group.

CONCLUSION

C23 has potential to be developed into a possible therapy for reperfusion injury after mesenteric ischemia and reperfusion.

Volume Based Resuscitation and Intestinal Microcirculation after Ischaemia/Reperfusion Injury: Results of an Exploratory Aortic Clamping Study in Pigs

OBJECTIVES

In the presence of ischaemia/reperfusion (I/R) induced endothelial injury, volume administration may not correlate with increased microcirculation. The aim of this study was to evaluate intestinal microcirculation after standardised sequential volume loading in an animal model of I/R injury following supracoeliac aortic clamping.

METHODS

This was a prospective exploratory pilot animal study. Intestinal I/R injury was induced in eight pigs during experimental thoraco-abdominal aortic repair. After 6 h of I/R, microcirculatory blood flow (mFlux, measured in the ileum using direct laser speckle contrast imaging) and macrohaemodynamic parameters (using trans-cardiopulmonary thermodilution) were measured and measurements were repeated after each of four sequential volume loading steps (VLS1 - 4). Each load was administered over 5 min followed by another 5 min for equilibration.

RESULTS

All animals survived until after VLS4. After 6 h of I/R cardiac output (CO) (p < .001) and mFlux (p < .001) had both decreased. CO increased again after VLS1 (p < .001) and VLS2 (p = .036), whereas mFlux did not change. In contrast, mFlux further decreased after VLS3 (p < .01) and VLS4 (p < .001), whereas CO did not change anymore. Extravascular lung water continued to increase after VLS2 (p = .046) and VLS4 (p = .049).

CONCLUSIONS

I/R leads to impaired intestinal microcirculation, which was not restored by volume administration in spite of improved CO. In contrast, further volume administration exceeding preload reserves was associated with additional decreases in the intestinal microcirculation. The potentially negative effect of excessive volume resuscitation after I/R injury should encourage further translational research.

Neutralization of Osteopontin Ameliorates Acute Lung Injury Induced by Intestinal Ischemia-Reperfusion

Intestinal ischemia-reperfusion (I/R) is associated with acute respiratory distress syndrome. Osteopontin (OPN), a glycoprotein secreted from immune-reactive cells, plays a deleterious role in various inflammatory diseases. Considering OPN as a pro-inflammatory molecule, we hypothesize that the treatment with its neutralizing antibody (anti-OPN Ab) protects mice against intestinal I/R-induced acute lung injury (ALI). Intestinal I/R was induced in mice by superior mesenteric artery occlusion with a vascular clip. After 45 min of occlusion, the clip was removed and anti-OPN Ab (25 μg/mouse) or normal IgG isotype control (25 μg/mouse) was immediately administrated intravenously. Blood, small intestine, and lung tissues were collected at 4 h after reperfusion for various analyses. After intestinal I/R, mRNA and protein levels of OPN were significantly induced in the small intestine, lungs, and blood relative to sham-operated animals. Compared with the IgG control group, treatment of anti-OPN Ab significantly reduced plasma levels of pro-inflammatory cytokine and chemokine (IL-6 and MIP-2) and organ injury markers (AST, ALT, and LDH). The histological architecture of the gut and lung tissues in anti-OPN Ab-treated intestinal I/R-induced mice showed significant improvement versus the IgG control mice. The lung inflammation measured by the levels of IL-6, IL-1β, and MIP-2 was also significantly downregulated in the anti-OPN Ab-treated mice as compared with the IgG control mice. Besides, the lung MPO and neutrophil infiltration in anti-OPN Ab-treated mice showed significant reduction as compared with the IgG control animals. In conclusion, we have demonstrated beneficial outcomes of anti-OPN Ab treatment in protecting against ALI, implicating a novel therapeutic potential in intestinal I/R.

Effect of atenolol pre-treatment in heart damage in a model of intestinal ischemia-reperfusion

PURPOSE

To investigate the effects of atenolol in inflammatory mediator and oxidative stress in a myocardial injury by intestinal ischemia/reperfusion in rat model.

METHODS

Adult Wistar male rats were randomly (n=8), anesthetized and divided in: Sham: submitted to operation only; group SS+IR: intravenous saline infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); group AT+IR: intravenous atenolol infusion (2 mg/kg) following superior mesenteric artery occlusion during 60 minutes (ischemia) and open for 120 minutes (reperfusion); and group AT+I+AT+R: intravenous atenolol infusion following superior mesenteric artery occlusion during 60 minutes (ischemia) and in the time 45 minutes other atenolol doses were administrated and the artery was open for 120 minutes (reperfusion), all animals were submitted to muscular relaxation for mechanical ventilation. In the end of experiment the animals were euthanized and the hearts tissue were morphology analyzed by histology and malondialdehyde by ELISA, and the plasma were analyzed for tumor necrosis factor-alpha by ELISA.

RESULTS

The group SS+IR demonstrated the higher malondialdehyde levels when compared with the atenolol treated-groups (p=0.001) in the heart tissue. The tumor necrosis factor-alpha level in plasma decrease in the treated groups when compared with SS+IR group (p=0.001). Histology analyses demonstrate pyknosis, edema, cellular vacuolization, presence of inflammatory infiltrate and band contraction in the heart tissue of the rats.

CONCLUSION

Atenolol significantly reduce the degree of cardiac damage after intestinal ischemia-reperfusion.

Pretreatment with indomethacin results in increased heat stroke severity during recovery in a rodent model of heat stroke

It has been suggested that medications can increase heat stroke (HS) susceptibility/severity. We investigated whether the nonsteroidal anti-inflammatory drug (NSAID) indomethacin (INDO) increases HS severity in a rodent model. Core temperature (T_c) of male, C57BL/6J mice (n = 45) was monitored continuously, and mice were given a dose of INDO [low dose (LO) 1 mg/kg or high dose (HI) 5 mg/kg in flavored treat] or vehicle (flavored treat) before heating. HS animals were heated to 42.4°C and euthanized at three time points for histological, molecular, and metabolic analysis: onset of HS [maximal core temperature (T_c,Max)], 3 h of recovery [minimal core temperature or hypothermia depth (HYPO)], and 24 h of recovery (24 h). Nonheated (control) animals underwent identical treatment in the absence of heat. INDO (LO or HI) had no effect on physiological indicators of performance (e.g., time to T_c,Max, thermal area, or cooling time) during heating or recovery. HI INDO resulted in 45% mortality rate by 24 h (HI INDO + HS group). The gut showed dramatic increases in gross morphological hemorrhage in HI INDO + HS in both survivors and nonsurvivors. HI INDO + HS survivors had significantly lower red blood cell counts and hematocrit suggesting significant hemorrhage. In the liver, HS induced cell death at HYPO and increased inflammation at T_c,Max, HYPO, and 24 h; however, there was additional effect with INDO + HS group. Furthermore, the metabolic profile of the liver was disturbed by heat, but there was no additive effect of INDO + HS. This suggests that there is an increase in morbidity risk with INDO + HS, likely resulting from significant gut injury.NEW & NOTEWORTHY This paper suggests that in a translational mouse model, NSAIDs may be counterindicated in situations that put an individual at risk of heat injury. We show here that a small, single dose of the NSAID indomethacin before heat stroke has a dramatic and highly damaging effect on the gut, which ultimately leads to increased systemic morbidity.

Naringin protects viscera from ischemia/reperfusion injury by regulating the nitric oxide level in a rat model

We investigated the effects of naringin on small intestine, liver, kidney and lung recovery after ischemia/reperfusion (I/R) injury of the gut. Rats were divided randomly into four groups of eight. Group A was the sham control; group B was ischemic for 2 h; group C was ischemic for 2 h and re-perfused for 2 h (I/R); group D was treated with 50 mg/kg naringin after ischemia, then re-perfused for 2 h. Endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) expressions were detected by immunolabeling. We also measured arginase activity, amounts of nitric oxide (NO) and total protein. iNOS was increased significantly in the small intestine, liver and kidney in group C. iNOS was decreased significantly only in small intestine and lung in group D. eNOS was increased significantly in the small intestine, liver and lung in group C. eNOS was decreased in small intestine, liver and lung in group D; however, eNOS was decreased in the kidney in group C and increased in the kidney in group D. The amount of NO was decreased significantly in all tissues in group D, but arginase activity was decreased in the small intestine and lung, increased in the kidney and remained unchanged in the liver in group D. The total protein increased in the small intestine and liver in group D, but decreased significantly in the kidney and lung in group D. Naringin had significant, salutary effects on the biochemical parameters of I/R by decreasing the NO level, equilibrating iNOS and eNOS expressions, and decreasing arginase activity.

EPHA4-FC TREATMENT REDUCES ISCHEMIA/REPERFUSION-INDUCED INTESTINAL INJURY BY INHIBITING VASCULAR PERMEABILITY

The inflammatory response is characterized by increased endothelial permeability, which permits the passage of fluid and inflammatory cells into interstitial spaces. The Eph/ephrin receptor ligand system plays a role in inflammation through a signaling cascade, which modifies Rho-GTPase activity. We hypothesized that blocking Eph/ephrin signaling using an EphA4-Fc would result in decreased inflammation and tissue injury in a model of ischemia/reperfusion (I/R) injury. Mice undergoing intestinal I/R pretreated with the EphA4-Fc had significantly reduced intestinal injury compared to mice injected with the control Fc. This reduction in I/R injury was accompanied by significantly reduced neutrophil infiltration, but did not affect intestinal inflammatory cytokine generation. Using microdialysis, we identified that intestinal I/R induced a marked increase in systemic vascular leakage, which was completely abrogated in EphA4-Fc-treated mice. Finally, we confirmed the direct role of Eph/ephrin signaling in endothelial leakage by demonstrating that EphA4-Fc inhibited tumor necrosis factor-α-induced vascular permeability in human umbilical vein endothelial cells. This study identifies that Eph/ephrin interaction induces proinflammatory signaling in vivo by inducing vascular leak and neutrophil infiltration, which results in tissue injury in intestinal I/R. Therefore, therapeutic targeting of Eph/ephrin interaction using inhibitors, such as EphA4-Fc, may be a novel method to prevent tissue injury in acute inflammation by influencing endothelial integrity and by controlling vascular leak.

Ischemia/Reperfusion

Ischemic disorders, such as myocardial infarction, stroke, and peripheral vascular disease, are the most common causes of debilitating disease and death in westernized cultures. The extent of tissue injury relates directly to the extent of blood flow reduction and to the length of the ischemic period, which influence the levels to which cellular ATP and intracellular pH are reduced. By impairing ATPase-dependent ion transport, ischemia causes intracellular and mitochondrial calcium levels to increase (calcium overload). Cell volume regulatory mechanisms are also disrupted by the lack of ATP, which can induce lysis of organelle and plasma membranes. Reperfusion, although required to salvage oxygen-starved tissues, produces paradoxical tissue responses that fuel the production of reactive oxygen species (oxygen paradox), sequestration of proinflammatory immunocytes in ischemic tissues, endoplasmic reticulum stress, and development of postischemic capillary no-reflow, which amplify tissue injury. These pathologic events culminate in opening of mitochondrial permeability transition pores as a common end-effector of ischemia/reperfusion (I/R)-induced cell lysis and death. Emerging concepts include the influence of the intestinal microbiome, fetal programming, epigenetic changes, and microparticles in the pathogenesis of I/R. The overall goal of this review is to describe these and other mechanisms that contribute to I/R injury. Because so many different deleterious events participate in I/R, it is clear that therapeutic approaches will be effective only when multiple pathologic processes are targeted. In addition, the translational significance of I/R research will be enhanced by much wider use of animal models that incorporate the complicating effects of risk factors for cardiovascular disease. © 2017 American Physiological Society. Compr Physiol 7:113-170, 2017.

miR-34a-5p Inhibition Alleviates Intestinal Ischemia/Reperfusion-Induced Reactive Oxygen Species Accumulation and Apoptosis via Activation of SIRT1 Signaling

AIMS

Reactive oxygen species (ROS) generation and massive epithelial apoptosis are critical in the pathogenesis of intestinal ischemia/reperfusion (I/R) injury. We previously found that the Sirtuin 1 (SIRT1)-mediated antioxidant pathway was impaired in the intestine after I/R. Here, we investigate the potential role of SIRT1-targeting microRNAs (miRNAs) in regulating ROS accumulation and apoptosis in intestinal I/R, and the important role SIRT1 involved in.

RESULTS

C57BL/6 mice were subjected to intestinal I/R induced by occlusion of the superior mesenteric artery followed by reperfusion. Caco-2 cells were incubated under hypoxia/reoxygenation condition to mimic I/R in vivo. We find that SIRT1 is gradually repressed during the early reperfusion, and that this repression results in intestinal ROS accumulation and apoptosis. Using bioinformatics analysis and real-time PCR, we demonstrate that miR-34a-5p and miR-495-3p are significantly increased among the 41 putative miRNAs that can target SIRT1. Inhibition of miR-34a-5p, but not miR-495-3p, attenuates intestinal I/R injury, as demonstrated by repressing p66shc upregulation, manganese superoxide dismutase repression, and the caspase-3 activation in vitro and in vivo; it further alleviates systemic injury, as demonstrated by reducing inflammatory cytokine release, attenuating lung and liver lesions, and improving survival. Interestingly, SIRT1 plays an indispensable role in the protection afforded by miR-34a-5p inhibition.

INNOVATION

This study provides the first evidence of miRNAs in regulating oxidative stress and apoptosis in intestinal I/R.

CONCLUSION

miR-34a-5p knockdown attenuates intestinal I/R injury through promoting SIRT1-mediated suppression of epithelial ROS accumulation and apoptosis. This may represent a novel prophylactic approach to intestinal I/R injury. Antioxid. Redox Signal. 24, 961-973.

Murine Model of Intestinal Ischemia-reperfusion Injury

Intestinal ischemia is a life-threatening condition associated with a broad range of clinical conditions including atherosclerosis, thrombosis, hypotension, necrotizing enterocolitis, bowel transplantation, trauma and chronic inflammation. Intestinal ischemia-reperfusion (IR) injury is a consequence of acute mesenteric ischemia, caused by inadequate blood flow through the mesenteric vessels, resulting in intestinal damage. Reperfusion following ischemia can further exacerbate damage of the intestine. The mechanisms of IR injury are complex and poorly understood. Therefore, experimental small animal models are critical for understanding the pathophysiology of IR injury and the development of novel therapies. Here we describe a mouse model of acute intestinal IR injury that provides reproducible injury of the small intestine without mortality. This is achieved by inducing ischemia in the region of the distal ileum by temporally occluding the peripheral and terminal collateral branches of the superior mesenteric artery for 60 min using microvascular clips. Reperfusion for 1 hr, or 2 hr after injury results in reproducible injury of the intestine examined by histological analysis. Proper position of the microvascular clips is critical for the procedure. Therefore the video clip provides a detailed visual step-by-step description of this technique. This model of intestinal IR injury can be utilized to study the cellular and molecular mechanisms of injury and regeneration.

TLR4-HMGB1-, MyD88- and TRIF-dependent signaling in mouse intestinal ischemia/reperfusion injury

AIM: To characterize high-mobility group protein 1-toll-like receptor 4 (HMGB1-TLR4) and downstream signaling pathways in intestinal ischemia/reperfusion (I/R) injury.

METHODS: Forty specific-pathogen-free male C57BL/6 mice were randomly divided into five groups (n = 8 per group): sham, control, anti-HMGB1, anti-myeloid differentiation gene 88 (MyD88), and anti-translocating-chain-associating membrane protein (TRIF) antibody groups. Vehicle with the control IgG antibody, anti-HMGB1, anti-MyD88, or anti-TRIF antibodies (all 1 mg/kg, 0.025%) were injected via the caudal vein 30 min prior to ischemia. After anesthetization, the abdominal wall was opened and the superior mesenteric artery was exposed, followed by 60 min mesenteric ischemia and then 60 min reperfusion. For the sham group, the abdominal wall was opened for 120 min without I/R. Levels of serum nuclear factor (NF)-κB p65, interleukin (IL)-6, and tumor necrosis factor (TNF)-α were measured, along with myeloperoxidase activity in the lung and liver. In addition,morphologic changes that occurred in the lung and intestinal tissues were evaluated. Levels of mRNA transcripts encoding HMGB1 and NF-κB were measured by real-time quantitative PCR, and levels of HMGB1 and NF-κB protein were measured by Western blot. Results were analyzed using one-way analysis of variance.

RESULTS: Blocking HMGB1, MyD88, and TRIF expression by injecting anti-HMGB1, anti-MyD88, or anti-TRIF antibodies prior to ischemia reduced the levels of inflammatory cytokines in serum; NF-κB p65: 104.64 ± 11.89, 228.53 ± 24.85, 145.00 ± 33.63, 191.12 ± 13.22, and 183.73 ± 10.81 (P < 0.05); IL-6: 50.02 ± 6.33, 104.91 ± 31.18, 62.28 ± 6.73, 85.90 ± 17.37, and 78.14 ± 7.38 (P < 0.05); TNF-α, 43.79 ± 4.18, 70.81 ± 6.97, 52.76 ± 5.71, 63.19 ± 5.47, and 59.70 ± 4.63 (P < 0.05) for the sham, control, anti-HMGB1, anti-MyD88, and anti-TRIF groups, respectively (all in pg/mL).Antibodies also alleviated tissue injury in the lung and small intestine compared with the control group in the mouse intestinal I/R model. The administration of anti-HMGB1, anti-MyD88, and anti-TRIF antibodies markedly reduced damage caused by I/R, for which anti-HMGB1 antibody had the most obvious effect.

CONCLUSION: HMGB1 and its downstream signaling pathway play important roles in the mouse intestinal I/R injury, and the effect of the TRIF-dependent pathway is slightly greater.

Vagus Nerve Mediates the Neural Stem Cell Response to Intestinal Injury

BACKGROUND

Intestinal ischemia and reperfusion injury results in damage to elements critical to maintaining intestinal barrier function, including neurons and glia cells, which are part of the enteric nervous system (ENS). To limit inflammation, the ENS must be restored or replaced, yet the process by which this occurs is poorly understood. Multipotent progenitor cells called enteric nervous stem cells (ENSC) can differentiate into neurons or glia when stimulated. The ability of this cell population to respond to intestinal injury is unknown. In this study, we hypothesized that resolution of intestinal barrier injury would be associated with vagus nerve-mediated expansion of ENSCs.

STUDY DESIGN

Ischemia and reperfusion injury was reproduced in male mice by occluding the superior mesenteric artery for 30 minutes. Abdominal vagotomy was performed in a separate cohort to study the effects of the vagus nerve. Terminal ileum was harvested at various time points after reperfusion and analyzed with histology, flow cytometry, and immunohistochemistry.

RESULTS

Enteric nervous stem cell expansion occurs at 2, 4, and 8 hours after injury compared with sham (4.6% vs 2.1%; p < 0.001) and correlated with increased glial fibrillary acidic protein on immunohistochemistry. Vagotomy prevented both ENSC expansion and increased glial fibrillary acidic protein staining after injury. Intestinal permeability was restored to baseline by 48 hours after injury, but remained elevated in the vagotomy group compared with sham and injury alone at 48 hours (3.25 mg/mL vs 0.57 mg/mL and 0.26 mg/mL, respectively; p < 0.05).

CONCLUSIONS

Vagal-mediated expansion of ENSCs occurs after ischemia and reperfusion injury and results in improved kinetics of injury resolution.

AICAR attenuates organ injury and inflammatory response after intestinal ischemia and reperfusion

Intestinal ischemia and reperfusion (I/R) is encountered in various clinical conditions and contributes to multiorgan failure and mortality as high as 60% to 80%. Intestinal I/R not only injures the intestine, but affects remote organs such as the lung leading to acute lung injury. The development of novel and effective therapies for intestinal I/R are critical for the improvement of patient outcome. AICAR (5-aminoimidazole-4-carboxyamide ribonucleoside) is a cell-permeable compound that has been shown to possess antiinflammatory effects. The objective is to determine that treatment with AICAR attenuates intestinal I/R injury and subsequent acute lung injury (ALI). Male Sprague Dawley rats (275 to 325 g) underwent intestinal I/R injury with blockage of the superior mesenteric artery for 90 min and subsequent reperfusion. At the initiation of reperfusion, vehicle or AICAR (30 mg/kg BW) was given intravenously (IV) for 30 min. At 4 h after reperfusion, blood and tissues were collected for further analyses. Treatment with AICAR significantly decreased the gut damage score and the water content, indicating improvement in histological integrity. The treatment also attenuated tissue injury and proinflammatory cytokines, and reduced bacterial translocation to the gut. AICAR administration after intestinal I/R maintained lung integrity, attenuated neutrophil chemotaxis and infiltration to the lungs and decreased lung levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6. Inflammatory mediators, lung-inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins, were decreased in the lungs and lung apoptosis was significantly reduced after AICAR treatment. These data indicate that AICAR could be developed as an effective and novel therapeutic for intestinal I/R and subsequent ALI.

The effect of 2 mMol glutamine supplementation on HSP70 and TNF-α release by LPS stimulated blood from healthy children

OBJECTIVE

Glutamine has been shown to promote heat shock protein 70 (HSP70) release both within experimental in vitro models of sepsis (2-10 mM) and in adults post trauma (0.5 g/kg), although the efficacy varies and is dependent on the model used. The effect of glutamine supplementation on HSP70 release in children is less clear. Therefore, the aim of this study was to investigate the effect of 2 mM glutamine added to incubation media on HSP70 and inflammatory mediator release in an in vitro model of paediatric sepsis using whole blood from healthy paediatric volunteers.

METHODS

An in vitro whole blood endotoxin stimulation model using 1 μg/ml lipopolysaccharide (LPS) over a 24 h time period was used to investigate the effects of 2 mM glutamine on HSP70 and inflammatory mediator release in healthy children.

RESULTS

The addition of 2 mM glutamine to the incubation media significantly increased HSP70 release over time (p < 0.05). This was associated with an early pro-inflammatory effect on TNF-α release at 4 h (p < 0.005) which was not seen at 24 h. There was a non significant trend towards higher levels of IL-6 and IL-10 following the addition of 2 mM glutamine, which appears to differ from the response reported in adult and animal models.

CONCLUSION

Glutamine supplementation of incubation media promotes HSP70 and early TNF- α release in an in vitro model using blood samples from healthy children.

Guanylyl cyclase-G modulates jejunal apoptosis and inflammation in mice with intestinal ischemia and reperfusion

Background

Membrane bound guanylyl cyclase-G (mGC-G), a novel form of GC mediates ischemia and reperfusion (IR)-induced renal injury. We investigated the roles of mGC-G in intestinal IR-induced jejunal damage, inflammation, and apoptosis.

Materials and methods

Male C57BL/6 wild-type (WT) and mGC-G gene knockout (KO) mice were treated with a sham operation or 45 min of superior mesenteric arterial obstruction followed by 3, 6, 12, or 24 h of reperfusion.

Results

Sham-operated KO mice had significantly lower plasma nitrate and nitrite (NOx) levels and jejunal villus height, crypt depth, and protein expression of phosphorylated-nuclear factor-kappa-B (NF-κB), phosphorylated-c-Jun N-terminal kinases (JNK) 2/3, phosphorylated-p38, and B-cell lymphoma-2 (Bcl-2). They had significantly greater jejunal interleukin-6 mRNA, cytochrome c protein, and apoptotic index compared with sham-operated WT mice. Intestinal IR significantly decreased plasma NOx in WT mice and increased plasma NOx in KO mice. The jejunal apoptotic index and caspase 3 activities were significantly increased, and nuclear phosphorylated-NF-κB and phosphorylated-p38 protein were significantly decreased in WT, but not KO mice with intestinal IR. After reperfusion, KO mice had an earlier decrease in jejunal cyclic GMP, and WT mice had an earlier increase in jejunal proliferation and a later increase in cytosol inhibitor of kappa-B-alpha. Intestinal IR induced greater increases in plasma and jejunal interleukin-6 protein in WT mice and a greater increase in jejunal interleukin-6 mRNA in KO mice.

Conclusions

mGC-G is involved in the maintenance of jejunal integrity and intestinal IR-induced inflammation and apoptosis. These results suggest that targeting cGMP pathway might be a potential strategy to alleviate IR-induced jejunal damages.

Ischemic preconditioning and tacrolimus pretreatment as strategies to attenuate intestinal ischemia-reperfusion injury in mice

The intestine is highly sensitive to ischemia-reperfusion injury (IRI), a phenomenon occurring in different intestinal diseases. Several strategies to mitigate IRI are in experimental stages; unfortunately, no consensus has been reached about the most appropriate one. We report a protocol to study ischemic preconditioning (IPC) evaluation in mice and to combine IPC and tacrolimus (TAC) pretreatment in a warm ischemia model. Mice were divided into treated (IPC, TAC, and IPC + TAC) and untreated groups before intestinal ischemia. IPC, TAC, and IPC + TAC groups were able to decrease postreperfusion nitrites levels (P < .05). IPC-containing groups had a major beneficial effect by preserving the integrity of the intestinal histology (P < .05) and improving animal survival (P < .002) compared with TAC alone or the untreated group. The IPC + TAC group was the only one that showed significant improvement in lung histological analysis (P < .05). The TAC and IPC + TAC groups down-regulated intestinal expression of interleukin (II)-6 and IL1b more than 10-fold compared with the control group. Although IPC and TAC alone reduced intestinal IRI, the used of a combined therapy produced the most significant results in all the local and distant evaluated parameters.

Post-resuscitation intestinal microcirculation: its relationship with sublingual microcirculation and the severity of post-resuscitation syndrome

OBJECTIVE

Post-resuscitation syndrome has been recognized as one of the major causes of the poor outcomes of cardiopulmonary resuscitation. The aims of this study were to investigate the intestinal microcirculatory changes following cardiopulmonary resuscitation and relate those changes to sublingual microcirculation and the severity of post-resuscitation syndrome as measured by myocardial function and serum inflammatory cytokine levels.

METHODS

Twenty-five rats were randomized into three groups: (1) short duration of cardiac arrest (n=10): ventricular fibrillation (VF) was untreated for 4 min prior to 6 min of cardiopulmonary resuscitation (CPR); (2) long duration of cardiac arrest (n=10): VF was untreated for 8 min followed by 8 min of CPR; (3) sham control group (n=5): a sham operation was performed without VF induction and CPR. Intestinal and sublingual microcirculatory blood flow was visualized by a sidestream dark-field (SDF) imaging device at baseline and 1, 2, 4, 6, 8 h post-resuscitation. Myocardial function was measured by echocardiography and serum cytokine levels (TNF-α and IL-6) were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Both intestinal and sublingual microcirculatory blood flow decreased significantly with increasing duration of cardiac arrest and resuscitation. The decreases in intestinal microcirculatory blood flow were closely correlated with the reductions of sublingual microcirculatory blood flow (perfused small vessels density: r=0.772, p<0.01; microcirculatory flow index: r=0.821, p<0.01). The decreased microcirculatory blood flow was closely correlated with weakened myocardial function and elevated inflammatory cytokine levels.

CONCLUSIONS

The severity of post-resuscitation intestinal microcirculatory dysfunction is closely correlated with that of myocardial function and inflammatory cytokine levels. The measurement of sublingual microcirculation reflects changes of intestinal microcirculation and may therefore provide a new option for post-resuscitation monitoring.

Urocortin increased endothelial ICAM1 by cPLA2-dependent NF-κB and PKA pathways in HUVECs

Urocortin (Ucn1), a member of the corticotrophin-releasing hormone (CRH) family, has been reported to participate in inflammation. The increased expression of intercellular adhesion molecule 1 (ICAM1) plays important roles in inflammation and immune responses. Our previous results demonstrated that Ucn1 significantly enhanced the expression of ICAM1. However, the underlying mechanisms are still unknown. The purpose of this study is to investigate the detailed mechanisms of Ucn1-induced upregulation of ICAM1. Here, we characterized the mechanisms of Ucn1 usage to regulate ICAM1 expression in human umbilical vein endothelial cells (HUVECs). Our data revealed that Ucn1 increased ICAM1 and cyclooxygenase 2 (COX2) expressions in a time-dependent manner via CRH receptor 2 (CRHR2). In addition, COX2 was involved in ICAM1 upregulation. Furthermore, Ucn1 could increase the expression and phosphorylation of cytosolic phospholipases A2 (cPLA2) in a time-dependent manner via CRHR2 and CRHR1. Moreover, ablation of cPLA2 by the inhibitor pyrrophenone or siRNA attenuated the ICAM1 increase induced by Ucn1. In addition, nuclear factor κB (NF-κB) was activated, indicated by the increase in nuclear p65NF-κB expression and phosphorylation of p65NF-κB, depending on cPLA2 and CRHR2 activation. Pyrrolidinedithiocarbamic acid, an inhibitor of NF-κB, abolished the elevation of ICAM1 but not COX2. Also, Ucn1 increased the production of prostaglandin E2 (PGE2) which further activated protein kinase A (PKA)-CREB pathways dependent of cPLA2 via CRHR2. Moreover, the increase in NF-κB phosphorylation was not affected by the selective COX2 inhibitor NS-398 or the PKA inhibitor H89. In conclusion, these data indicate that Ucn1 increase the ICAM1 expression via cPLA2-NF-κB and cPLA2-COX2-PGE2-PKA-CREB pathways by means of CRHR2.

Acute arterial mesenteric ischemia and reperfusion: Macroscopic and MRI findings, preliminary report

AIM: To explore the physiopathology and magnetic resonance imaging (MRI) findings in an animal model of acute arterial mesenteric ischemia (AAMI) with and without reperfusion.

METHODS: In this study, 8 adult Sprague-Dawley rats underwent superior mesenteric artery (SMA) ligation and were then randomly divided in two groups of 4. In group I, the ischemia was maintained for 8 h. In group II, 1-h after SMA occlusion, the ligation was removed by cutting the thread fixed on the back of the animal, and reperfusion was monitored for 8 h. MRI was performed using a 7-T system.

RESULTS: We found that, in the case of AAMI without reperfusion, spastic reflex ileus, hypotonic reflex ileus, free abdominal fluid and bowel wall thinning are present from the second hour, and bowel wall hyperintensity in T2-W sequences are present from the fourth hour. The reperfusion model shows the presence of early bowel wall hyperintensity in T2-W sequences after 1 h and bowel wall thickening from the second hour.

CONCLUSION: Our study has shown that MRI can assess pathological changes that occur in the small bowel and distinguish between the presence and absence of reperfusion after induced acute arterial ischemia.

A phase 2 randomized, double-blind, placebo-controlled study of the safety and efficacy of talactoferrin in patients with severe sepsis

OBJECTIVES

Lactoferrin is a glycoprotein with anti-infective and anti-inflammatory properties found in secretions and immune cells. Talactoferrin alfa, a recombinant form of human lactoferrin, has similar properties and plays an important role in maintaining the gastrointestinal mucosal barrier integrity. In experimental animal models, administration of talactoferrin reduces translocation of bacteria from the gut into the systemic circulation and mortality from sepsis. Our objective was to determine if talactoferrin could reduce 28-day all-cause mortality in patients with severe sepsis and to assess its safety.

DESIGN

Prospective, randomized, double-blind, placebo-controlled, multicenter phase 2 trial.

SETTING

Adult ICUs and emergency departments in the United States.

PATIENTS

One hundred ninety-four adults within 24 hrs of the onset of severe sepsis.

INTERVENTIONS

Enterally administered talactoferrin 1.5g or placebo every 8 hrs for up to 28 days or until discharge from the ICU.

MEASUREMENTS AND MAIN RESULTS

Modified intention-to-treat analysis was used to assess the primary (28-day all-cause mortality) and secondary endpoints. The all-cause mortality at 28 days was 26.9% in the placebo group and 14.4% in the talactoferrin group (two-sided p = 0.052), representing a 12.5% absolute and a 46.5% relative reduction in mortality, meeting the protocol-specified primary endpoint. Reduction in all cause mortality was sustained at 6 months (p = 0.039). These reductions in mortality were observed across a wide spectrum of subgroups. The drug was well tolerated with a safety profile similar to that of placebo.

CONCLUSIONS

Enteral administration of talactoferrin reduced 28-day all-cause mortality in patients with severe sepsis. This reduction in mortality was sustained at 6 months. Talactoferrin was very well tolerated.

Electroacupuncture at Zusanli (ST36) Prevents Intestinal Barrier and Remote Organ Dysfunction following Gut Ischemia through Activating the Cholinergic Anti-Inflammatory-Dependent Mechanism

This study investigated the protective effect and mechanism of electroacupuncture at ST36 points on the intestinal barrier dysfunction and remote organ injury after intestinal ischemia and reperfusion injury in rats. Rats were subjected to gut ischemia for 30 min, and then received electroacupuncture for 30 min with or without abdominal vagotomy or intraperitoneal administration of cholinergic α 7 nicotinic acetylcholine receptor ( α 7nAChR) inhibitor. Then we compared its effects with electroacupuncture at nonchannel points, vagal nerve stimulation, or intraperitoneal administration of cholinergic agonist. Cytokine levels in plasma and tissue of intestine, lung, and liver were assessed 60 min after reperfusion. Intestinal barrier injury was detected by histology, gut injury score, the permeability to 4 kDa FITC-dextran, and changes in tight junction protein ZO-1 using immunofluorescence and Western blot. Electroacupuncture significantly lowered the levels of tumor necrosis factor- α and interleukin-8 in plasma and organ tissues, decreased intestinal permeability to FITC-dextran, and prevented changes in ZO-1 protein expression and localization. However, abdominal vagotomy or intraperitoneal administration of cholinergic α 7nAChR inhibitor reversed these effects of electroacupuncture. These findings suggest that electroacupuncture attenuates the systemic inflammatory response through protection of intestinal barrier integrity after intestinal ischemia injury in the presence of an intact vagus nerve.

Cyclic arginine-glycine-aspartate attenuates acute lung injury in mice after intestinal ischemia/reperfusion

Introduction

Intestinal ischemia is a critical problem resulting in multiple organ failure and high mortality of 60 to 80%. Acute lung injury (ALI) is a common complication after intestinal ischemia/reperfusion (I/R) injuries and contributes to the high mortality rate. Moreover, activated neutrophil infiltration into the lungs is known to play a significant role in the progression of ALI. Integrin-mediated interaction is involved in neutrophil transmigration. Synthetic peptides containing an arginine-glycine-aspartate sequence compete with adhesive proteins and inhibit integrin-mediated interaction and signaling. Thus, we hypothesized that the administration of a cyclic arginine-glycine-aspartate peptide (cRGD) inhibited neutrophil infiltration and provided protection against ALI induced by intestinal I/R.

Methods

Ischemia in adult male C57BL/6 mice was induced by fastening the superior mesenteric artery with 4-0 suture. Forty-five minutes later, the vascular suture was released to allow reperfusion. cRGD (5 mg/kg body weight) or normal saline (vehicle) was administered by intraperitoneal injection 1 hour prior to ischemia. Blood, gut, and lung tissues were collected 4 hours after reperfusion for various measurements.

Results

Intestinal I/R caused severe widespread injury to the gut and lungs. Treatment with cRGD improved the integrity of microscopic structures in the gut and lungs, as judged by histological examination. Intestinal I/R induced the expression of β₁, β₂ and β₃ integrins, intercellular adhesion molecule-1, and fibronectin. cRGD significantly inhibited myeloperoxidase activity in the gut and lungs, as well as neutrophils and macrophages infiltrating the lungs. cRGD reduced the levels of TNF-α and IL-6 in serum, in addition to IL-6 and macrophage inflammatory protein-2 in the gut and lungs. Furthermore, the number of TUNEL-staining cells and levels of cleaved caspase-3 in the lungs were significantly lowered in the cRGD-treated mice in comparison with the vehicle mice.

Conclusions

Treatment with cRGD effectively protected ALI and gut injury, lowered neutrophil infiltration, suppressed inflammation, and inhibited lung apoptosis after intestinal I/R. Thus, there is potential for developing cRGD as a treatment for patients suffering from ALI caused by intestinal I/R.

Defining the nonreturn time for intestinal ischemia reperfusion injury in mice

Among the abdominal organs, the intestine is probably the most sensitive to ischemia reperfusion injury (IRI), a phenomenon that occurs in many intestinal disorders. Few studies have reported in detail the impact of intestinal ischemia time in mice. We evaluated the effect of various warm intestinal ischemia times in an intestinal IRI model in mice. Adult male Balb/c mice were divided into 4 groups that differed in intestinal ischemia time: G1, 30; minutes; G2, 35 minutes; G3, 40 minutes; and G4, 45 minutes. Histological evaluation showed average Park scores as follows: G1 0.6 ± 0.55; G2 1.8 ± 0.45; G3 4.8 ± 2.25; and G4 5 ± 1.79. All animals from G1 survived 30 hours. G2 animals showed intermediate behavior with all succumbing between 18 and 30 hours postprocedure. G3 and G4 displayed similar survival results with animals succumbing before 6 hours after intestinal reperfusion. These data showed that Park index scores of 3 or higher were related to early death. We concluded that the 5 minutes between 35 and 40 minutes is the critical limit, after which all mice die after reperfusion. This result may represent a valuable tool for future research in mice.

Pretreatment with pentoxifylline attenuates lung injury induced by intestinal ischemia/reperfusion in rats

PURPOSE

To investigate the protective effect of pentoxifylline against the lung injury observed after intestinal ischemia (I) followed by a period of reperfusion (R).

METHODS

Twenty-eight male Wistar rats were equally divided into 4 experimental groups and operated under ketamine-xylazine anesthesia. (1) Sham: falsely-operated animals; (2) SS+IR: intestinal ischemia was accomplished by clipping the superior mesenteric artery during 60 minutes, with an administration of a standard volume of saline solution (SS) 5 min before the end of the ischemia period; the clip was then releases or a 120-min period of reperfusion; (3) I+PTX+R: ischemia as above, PTX was administered (25 mg/kg) and the gut reperfused as above; (4) PTX+I+PTX+R: Five minutes before arterial occlusion PTX was administered; the superior mesenteric artery was then clipped for 60 minutes. After 55-min ischemia, an additional dosis of PTX was administered; the clip was removed for reperfusion as above. At the 60th min of reperfusion a third dosis of PTX was administered.

RESULTS

PTX markedly attenuated lung injury as manifested by significant decreases (all P<0.001 as compared with the SS+IR group) of pulmonary wet/dry tissue weight ratio, total protein content, myeloperoxidase activity and tumor necrosis factor-alpha. Moreover, it was apparent that in the group PTX+I+PTX+R the improvements have been even more significant.

CONCLUSION

PTX exerted a protective effect on the lung from the injuries caused by intestinal ischemia/reperfusion.

Isoflurane post-conditioning protects against intestinal ischemia-reperfusion injury and multiorgan dysfunction via transforming growth factor-β1 generation

OBJECTIVE

This study examined volatile anesthetic-mediated protection against intestinal ischemia-reperfusion injury (IRI).

BACKGROUND

Intestinal IRI is a devastating complication in the perioperative period leading to systemic inflammation and multiorgan dysfunction. Volatile anesthetics, including isoflurane, have anti-inflammatory effects. We aimed to determine whether isoflurane, given after intestinal ischemia, protects against intestinal IRI and the mechanisms involved in this protection.

METHODS

: After IACUC approval, mice were anesthetized with pentobarbital and subjected to 30 minutes of superior mesenteric artery ischemia, followed by 4 hours of equianesthetic doses of pentobarbital or isoflurane. Five hours after reperfusion, small intestine tissues were analyzed for morphological injury, apoptosis, neutrophil infiltration, proinflammatory mRNAs, and TGF-(Transforming Growth Factor-)β1 levels. We also assessed hepatic and renal injury after intestinal IRI.

RESULTS

Intestinal IRI with pentobarbital led to significant small intestinal dysfunction with increased mucosal injury, TUNEL (transferase biotin-dUTP nick end-labeling)-positive cells, neutrophil infiltration, and proinflammatory mRNAs as well as elevated plasma alanine aminotransferase and creatinine levels. Isoflurane exposure after IRI led to significant attenuation of intestinal, hepatic, and renal injuries. Furthermore, the protective effects of isoflurane were abolished by treatment with a TGF-β1 neutralizing antibody before induction of IRI. Finally, isoflurane exposure led to increased TGF-β1 levels in intestinal epithelial cells and in plasma.

CONCLUSIONS

Our findings demonstrate that isoflurane post-conditioning protects against small intestinal injury and hepatic and renal dysfunction after severe intestinal IRI via induction of intestinal epithelial TGF-β1. Our findings support therapeutic applications of volatile anesthetics during the intraoperative and postoperative periods and imply an important role of TGF-β1 signaling in modulating multiorgan injury.

Effects of exogenous carbon monoxide on p38 MAPKs expression in rats with intestinal ischemia reperfusion injury

AIM: To investigate the possible mechanism underlying the preventive effect of exogenous carbon monoxide (CO) on multiple organ injury induced by intestinal ischemia-reperfusion (IIR) in rats.

METHODS: Sixty-four male Wistar rats were randomly and equally allocated into eight groups. IIR was induced in rats by clamping the superior mesenteric artery (SMA) for 60 min and reperfusing for 120 min. Group A and sham operation did not undergo SMA clamping. Group B underwent SMA clamping for 60 min and reperfusing for 120 min. Groups C1/C2, D1/D2, and E1/E2 inhaled 100 and 250 µL/L CO 10, 60 min before SMA clamping and 60 min after reperfusion, respectively. The expression of p38 mitogen-activated protein kinases (MAPKs) in different tissues was detected by Western blot.

RESULTS: Compared to Group A, the expression of p38 MAPKs in the intestine, lung and liver increased in Group B, but the differences were not significant (0.468 ± 0.213 vs 0.474 ± 0.151; 0.439 ± 0.111 vs 0.482 ± 0.103; 0.622 ± 0.112 vs 0.654 ± 0.016, all P > 0.05). Compared to Group B, a marked increase in p38 MAPKs expression in the intestine, lung and liver was detected in Groups C1/C2, D1/D2, and E1/E2 (1.540 ± 0.346, 1.626 ± 0.277, 1.36 5± 0.233, 1.483 ± 0.265, 1.353 ± 0.234, 1.372 ± 0.2731 vs 0.474 ± 0.151; 1.654 ± 0.211, 1.701 ± 0.101, 1.398 ± 0.245, 1.444 ± 0.272, 1.288 ± 0.218, 1.366 ± 0.244 vs 0.482 ± 0.103; 1.695 ± 0.234, 1.723 ± 0.213, 1.423 ± 0.221, 1.586 ± 0.254, 1.322 ± 0.261, 1.411 ± 0.296 vs 0.654 ± 0.016, all P < 0.05).

CONCLUSION: Exogenous CO provides protection against IIR-induced multiple organ injury possibly by modulating the expression of p38 MAPKs in rats.

Cell biology of ischemia/reperfusion injury

Disorders characterized by ischemia/reperfusion (I/R), such as myocardial infarction, stroke, and peripheral vascular disease, continue to be among the most frequent causes of debilitating disease and death. Tissue injury and/or death occur as a result of the initial ischemic insult, which is determined primarily by the magnitude and duration of the interruption in the blood supply, and then subsequent damage induced by reperfusion. During prolonged ischemia, ATP levels and intracellular pH decrease as a result of anaerobic metabolism and lactate accumulation. As a consequence, ATPase-dependent ion transport mechanisms become dysfunctional, contributing to increased intracellular and mitochondrial calcium levels (calcium overload), cell swelling and rupture, and cell death by necrotic, necroptotic, apoptotic, and autophagic mechanisms. Although oxygen levels are restored upon reperfusion, a surge in the generation of reactive oxygen species occurs and proinflammatory neutrophils infiltrate ischemic tissues to exacerbate ischemic injury. The pathologic events induced by I/R orchestrate the opening of the mitochondrial permeability transition pore, which appears to represent a common end-effector of the pathologic events initiated by I/R. The aim of this treatise is to provide a comprehensive review of the mechanisms underlying the development of I/R injury, from which it should be apparent that a combination of molecular and cellular approaches targeting multiple pathologic processes to limit the extent of I/R injury must be adopted to enhance resistance to cell death and increase regenerative capacity in order to effect long-lasting repair of ischemic tissues.

Lymph duct ligation during ischemia/reperfusion prevents pulmonary dysfunction in a rat model with ω-3 polyunsaturated fatty acid and glutamine

OBJECTIVE

The release of injurious factors into the mesenteric lymph from the ischemic intestine has been shown to contribute to lung injury and systemic inflammation after severe injury. We studied the effects of lung injury and systemic inflammatory reaction after intestinal ischemia/reperfusion and mesenteric lymph duct ligation with different nutritional statuses.

METHODS

Rats (n = 72) were fed with a normal diet or received one of three diets (enteral nutrition, glutamine, or ω-3 polyunsaturated fatty acid) that were isocaloric and isonitrogenous. After 7 d, rats were subjected to 60 min of intestinal ischemia, ischemia plus mesenteric lymph duct ligation, or sham procedures. After 3 d of ischemia, the lymph nodes, lung, intestinal, liver, and blood were harvested and analyzed.

RESULTS

In the different groups, lung injury, including levels of myeloperoxidase, nitric oxide, nitric oxide synthase, and the index of alveolar apoptosis, were partly prevented by mesenteric lymph duct ligation (P < 0.05). Likewise, the rats with ischemia/reperfusion, but not those with duct ligation plus ischemia/reperfusion, had a significant increase in intestinal permeability and decreased mucosal thickness. The serum cytokine and endotoxin concentrations were also lower in the lymph duct ligation groups, although there was no significant difference between lymph duct ligation and sham procedure. The lung and intestinal injuries were attenuated in the groups fed with glutamine and ω-3 polyunsaturated fatty acid.

CONCLUSION

These results indicate that lymph duct ligation prevents lung injury, a systemic inflammation reaction, and gut-barrier dysfunction. Enteral glutamine and ω-3 polyunsaturated fatty acid modified the gut inflammation, prevented lung injury, and attenuated the systemic inflammation reaction.

Antioxidative protection of dietary bilberry, chokeberry and Lactobacillus plantarum HEAL19 in mice subjected to intestinal oxidative stress by ischemia-reperfusion

Background

Ischemia-reperfusion (I/R) in the intestines is an inflammatory condition which activates leukocytes and reactive oxygen species (ROS) and leads to lipid peroxidation and DNA damage. Bilberry and chokeberry fruits are rich sources of polyphenols which may act as antioxidants and prevent lipid peroxidation. Lactic acid bacteria (LAB) may improve microbial status in the intestines and increase the metabolic activity towards polyphenolic degradation. The aim of the study was to clarify antioxidative effects of bilberry and chokeberry fruits alone and with addition of a LAB-strain, Lactobacillus plantarum HEAL19, in an I/R-model in mice.

Methods

Male BALB/cJ mice were fed the experimental diets for 10 days. Diets consisted of standard chow supplemented with either bilberry (Vaccinium myrtillus) or chokeberry (Aronia × prunifolia) powder alone or in combination with the LAB-strain Lactobacillus plantarum HEAL19. I/R-injury was induced by holding superior mesenteric artery clamped for 30 minutes followed by reperfusion for 240 minutes. Thereafter, colonic and caecal tissues and contents were collected. Malondialdehyde (MDA) was used as indicator of lipid peroxidation and was measured by a calorimetric assay, lactobacilli were cultured on Rogosa agar plates and Enterobacteriaceae on VRBG agar plates, anthocyanins and phenolic acids were analysed by HPLC-DAD-ESI-MSn.

Results

MDA was significantly decreased in the colon of groups fed bilberry alone (p = 0.030) and in combination with L. plantarum HEAL19 (p = 0.021) compared to the IR-control but not in chokeberry-fed groups. Supplementation with bilberry or chokeberry alone reduced the total number of lactobacilli on the mucosa. Higher concentrations of anthocyanins were found in the colon than in the caecum content of mice. A more varied composition of different anthocyanins was also observed in the colon content compared to the caecum of bilberry-fed mice. Phenolic acids formed by microbial degradation of the dietary polyphenols in the gut could be detected. More phenolic metabolites were found in the intestines of bilberry-fed mice than in the chokeberry-fed ones.

Conclusions

Bilberry alone and in combination with L. plantarum HEAL19 exerts a better protection against lipid peroxidation than chokeberry. These dietary supplements may be used to prevent or suppress oxidative stress.

Protective effect of carnosol on lung injury induced by intestinal ischemia/reperfusion

PURPOSE

Carnosol is a phenolic diterpene that has potent antioxidant and anti-inflammatory activities. The purpose of this study was to investigate the preconditioning effects of carnosol on lung injury induced by intestinal ischemia/reperfusion (II/R).

METHODS

Rats were divided into control, II/R, and carnosol groups. The II/R model was established by clamping the superior mesenteric artery for 1 h and reperfusion at 2, 4, and 6 h after ischemia. The carnosol group received 3 mg/kg carnosol intraperitoneally 1 h before the operation. The rats were then euthanized, and blood and lung specimens were obtained for analysis.

RESULTS

The II/R induced lung injury, characterized by histological changes and significant increasing of bronchoalveolar lavage fluid protein. The activity of lung tissue superoxide was weakened, the tissue myeloperoxidase activity and serum interleukin-6 level increased significantly in II/R groups. A strong positive expression of lung intercellular adhesion molecule-1 (ICAM-1) and nuclear factor kappa B (NF-kappaB) were observed. Pretreatment with carnosol markedly reduced lung injury by increasing the tissue superoxide activity and decreasing the myeloperoxidase activity and interleukin-6 level, which was parallel to the decreased expression of ICAM-1 and NF-kappaB.

CONCLUSION

Carnosol was able to ablate lung injury induced by II/R, partly attributed to the inhibition of NF-kappaB activation.

Morphological and apoptotic changes in the intestinal mucosa and lung parenchyma after ischaemic/reperfusion injury of the jejunum

Ischaemic/reperfusion (IR) injury of the small intestine may lead to the development of multiple organ failure. Little is known about the morphological changes occurring in the organs during the subacute course of this syndrome. The objective of this study was to observe histopathological features and the role of apoptosis in the jejunal mucosa and lung parenchyma after intestinal IR injury in a long-term experiment. Wistar rats (n = 36) were divided into 4 experimental groups (IR(10), IR(20), IR(30), S). Groups IR(10), IR(20) and IR(30) (each n = 10) were subjected to 1-hour ischaemia of the cranial mesenteric artery followed by 10, 20 or 30 days of reperfusion, respectively. The control group S (n = 6) was not subjected to ischaemia. The jejunal mucosa remained intact after all periods of reperfusion. Apoptotic cells were found particularly in the lamina propria, with the most significant difference observed in the IR(30) group (P < 0.01). The lung parenchyma had lower regenerative capacity, which was confirmed by a high index of histological damage after 30 days of reperfusion (P < 0.01) and by the presence of an increased number of apoptotic cells, especially in the pulmonary interstitium. The number of apoptotic cells was ten times higher than in the control group (P < 0.001).

Effects of intestinal ischemia/reperfusion on P-glycoprotein mediated biliary and renal excretion of rhodamine123 in rat

To analyze the effects of I/R on P-gp function in liver and kidney, biliary and urinary excretions of rhodamine123 as a substrate of P-gp were examined in rats. The effects of reperfusion time on change and recovery of P-gp function were also examined. The biliary and renal clearance of rhodamine123 significantly decreased at 3 hr after reperfusion, but returned to control levels at 24 hr after reperfusion. These results suggest that intestinal I/R-induced decrease in P-gp-mediated biliary and renal excretion of rhodamine123 is litely due to impairment of P-gp-mediated transport ability. The level of P-gp protein in liver decreased and that of iNOS mRNA increased at 3 hr after reperfusion and both levels returned to control levels at 24 hr after reperfusion. No marked change in the levels of P-gp protein and iNOS mRNA was observed in kidney at 3 hr and 24 hr after reperfusion. Thus, decrease in biliary excretion of rhodamine123 would appear due in part to decrease in expression of P-gp, caused by increase in lipid peroxidation levels through iNOS mRNA.