Acute hyperglycemia worsens hepatic ischemia/reperfusion injury in rats

Plexin C1 influences immune response to intracellular LPS and survival in murine sepsis

BACKGROUND

Intracellular sensing of lipopolysaccharide (LPS) is essential for the immune response against gram-negative bacteria and results in activation of caspase-11 and pyroptotic cell death with fatal consequences in sepsis. We found the neuronal guidance receptor plexin C1 (PLXNC1) influences the intracellular response to LPS.

METHODS

We employed a murine model of sepsis via cecal ligation and binding (CLP), using PLXNC1-/- mice and littermate controls, and additionally transfected murine bone-marrow-derived macrophages (BMDMs) from both genotypes with LPS to achieve activation of the noncanonical inflammasome ex vivo. Additionally, we transfected the PLXNC1 ligand SL4c-d in vivo and ex vivo to examine its effect on intracellular LPS response.

RESULTS

We found the neuronal guidance receptor PLXNC1 dampens the intracellular response to LPS by interacting with adenylate cyclase 4 (ADCY4) and protein kinase A activity, which in turn diminishes caspase-11 expression. The absence of PLXNC1 results in excessive inflammation marked by increased cytokine release, increased secondary organ injury and reduced sepsis survival in a murine sepsis model induced by CLP. Notably, administration of SL4c-d-peptide ligand of PLXNC1-reduces the inflammatory response during CLP-induced sepsis and improves survival.

CONCLUSIONS

These results elucidate a previously unknown mechanism for PLXNC1 suppressing excessive noncanonical inflammasome activity and offer a new potential target for treatment of sepsis with its detrimental effects.

Optimizing DCD Liver Grafts With Prolonged Warm Ischemic Time Using Stabilized Plasmin in a Static Cold Storage Orthotopic Rat Liver Transplant Model

Background

The clinical success of liver transplantation has led to increased demand, requiring further expansion of the donor pool. Therapeutic interventions to optimize organs from donation after circulatory death (DCD) have significant potential to mitigate the organ shortage. Dysfunction in DCD liver grafts is mediated by microvascular thrombosis during the warm ischemic period, and strategies that reduce this thrombotic burden may improve graft function. We hypothesized that the administration of the fibrinolytic enzyme plasmin to the donor organ during the cold storage period would reduce the thrombotic burden and improve DCD liver graft function.

Methods

In 2 separate cohorts, 32 syngeneic orthotopic rat liver transplants were performed in Lewis rats. Livers were procured from donors with 45 min of warm ischemic injury. Liver grafts were flushed with histidine-tryptophan-ketoglutarate preservation solution mixed with either plasmin (experimental group) or albumin (control group). All investigators were blinded to treatment group. After preparing the liver for implant using a modified cuff technique, the liver was stored for 1 h by static cold storage at 4 °C. Immediately before implantation, the liver graft was flushed, and this effluent was analyzed for fibrin degradation products to determine graft clot burden. Twenty-four hours following transplantation, animals were euthanized, and samples were collected.

Results

Recipient survival was significantly higher for DCD liver grafts treated with plasmin compared with control. Moreover, histology of liver graft tissue immediately before implant reflected significantly reduced congestion in plasmin-treated livers (score, mean ± SD: 0.73 ± 0.59 versus 1.12 ± 0.48; P = 0.0456). The concentration of fibrin degradation products in the final flush before implantation was significantly reduced in plasmin-treated livers (743 ± 136 versus 10 919 ± 4642 pg/mL; P = 0.0001), reflecting decreased clot burden in the graft.

Conclusions

The present study demonstrates that plasmin improves survival and may reduce thrombotic burden in DCD liver grafts with prolonged warm ischemic injury, meriting further study.

Olprinone, a Selective Phosphodiesterase III Inhibitor, Has Protective Effects in a Septic Rat Model after Partial Hepatectomy and Primary Rat Hepatocyte

Olprinone (OLP) is a selective inhibitor of phosphodiesterase III and is used clinically in patients with heart failure and those undergoing cardiac surgery; however, little is known about the effects of OLP on hepatoprotection. The purpose of this study aimed to determine whether OLP has protective effects in in vivo and in vitro rat models of endotoxin-induced liver injury after hepatectomy and to clarify the mechanisms of action of OLP. In the in vivo model, rats underwent 70% partial hepatectomy and lipopolysaccharide treatment (PH/LPS). OLP administration increased survival by 85.7% and decreased tumor necrosis factor-α, C-X-C motif chemokine ligand 1, and inducible nitric oxide synthase (iNOS) mRNA expression in the livers of rats treated with PH/LPS. OLP also suppressed nuclear translocation and/or DNA binding ability of nuclear factor kappa B (NF-κB). Pathological liver damage induced by PH/LPS was alleviated and neutrophil infiltration was reduced by OLP. Primary cultured rat hepatocytes treated with the pro-inflammatory cytokine interleukin-1β (IL-1β) were used as a model of in vitro liver injury. Co-treatment with OLP inhibited dose-dependently IL-1β-stimulated iNOS induction and NF-κB activation. Our results demonstrate that OLP may partially inhibit the induction of several inflammatory mediators through the suppression of NF-κB and thus prevent liver injury induced by endotoxin after liver resection.

The Role of Gut Microbiota and Circadian Rhythm Oscillation of Hepatic Ischemia-Reperfusion Injury in Diabetic Mice

Circadian rhythm oscillation and the gut microbiota play important roles in several physiological functions and pathology regulations. In this study, we aimed to elucidate the characteristics of diabetic hepatic ischemia-reperfusion injury (HIRI) and the role of the intestinal microbiota in diabetic mice with HIRI. Hepatic ischemia-reperfusion injury surgery was performed at ZT0 or ZT12. The liver pathological score and the serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were analyzed to evaluate liver injury. We conducted an FMT experiment to examine the role of intestinal microbiota in diabetic mice with HIRI. The 16S rRNA gene sequencing of fecal samples was performed for microbial analysis. Our results showed that hyperglycemia aggravated HIRI in diabetic mice, but there was no diurnal variation seen in diabetic HIRI. We also demonstrated that there were significant alterations in the gut microbiota composition between the diabetic and control mice and that gut microbiota transplantation from diabetic mice had obvious harmful effects on HIRI. These findings provide some useful information for the future research of diabetic mice with HIRI.

Effect of Dexmedetomidine Preconditioning on Hepatic Ischemia-Reperfusion Injury in Acute Hyperglycemic Rats

BACKGROUND

Acute hyperglycemia frequently occurs in stressful situations, including liver transplantation or hepatic surgery, which may affect the protective effects of dexmedetomidine preconditioning and increase postoperative mortality. Therefore, this study aimed to investigate the effects of dexmedetomidine on hepatic ischemia-reperfusion injury in acute hyperglycemia.

METHODS

Thirty-six Sprague-Dawley rats were randomly assigned to 6 groups, including a combination between 2 glycemic (normo- and hyperglycemia) and 3 ischemia-reperfusion conditions (sham, ischemia-reperfusion only, and dexmedetomidine plus ischemia-reperfusion). Dexmedetomidine 70 μg/kg was preconditioned 30 minutes before ischemic injury. After 6 hours of reperfusion, serum aminotransferase levels were measured to confirm the hepatic tissue injury. Furthermore, inflammatory (nuclear factor-κb, tumor necrosis factor-α, and interleukin-6) and oxidative stress markers (malondialdehyde and superoxide dismutase) were detected.

RESULTS

Ischemia-reperfusion injury significantly increased the serum levels of aminotransferase and inflammatory and oxidative stress markers. These ischemia-reperfusion-induced changes were further exacerbated in hyperglycemia and were significantly attenuated by dexmedetomidine preconditioning. However, the effects of dexmedetomidine in hyperglycemia were lesser than those in normoglycemia (P < .05 for aminotransferases, inflammatory markers, malondialdehyde, and superoxide dismutase).

CONCLUSIONS

These findings suggest that the protective effects of dexmedetomidine preconditioning may be intact against hepatic ischemia-reperfusion injury in acute hyperglycemia. Although its effects appeared to be relatively reduced, this may be because of the increase in oxidative stress and inflammatory response caused by acute hyperglycemia. To determine whether the effects of dexmedetomidine itself would be impaired in hyperglycemia, further study is needed.

COMBINATION THERAPY WITH A SENSE OLIGONUCLEOTIDE TO INDUCIBLE NITRIC OXIDE SYNTHASE MRNA AND HUMAN SOLUBLE THROMBOMODULIN IMPROVES SURVIVAL OF SEPSIS MODEL RATS AFTER PARTIAL HEPATECTOMY

ABSTRACT

Sepsis after a major hepatectomy is a critical problem. In septic shock, the inflammatory mediator, nitric oxide (NO), is overproduced in hepatocytes and macrophages. The natural antisense (AS) transcripts, non-coding RNAs, are transcribed from a gene that encodes inducible nitric oxide synthase (iNOS). iNOS AS transcripts interact with and stabilize iNOS mRNAs. A single-stranded "sense oligonucleotide" (designated as SO1) corresponding to the iNOS mRNA sequence inhibits mRNA-AS transcript interactions and reduces iNOS mRNA levels in rat hepatocytes. In contrast, recombinant human soluble thrombomodulin (rTM) treats disseminated intravascular coagulopathy by suppressing coagulation, inflammation, and apoptosis. In this study, the combination therapy of SO1 and a low dose of rTM was evaluated for hepatoprotection in a rat septic shock model after partial hepatectomy. Rats underwent 70% hepatectomy, followed by intravenous (i.v.) injection of lipopolysaccharide (LPS) after 48 h. SO1 was injected (i.v.) simultaneously with LPS, whereas rTM was injected (i.v.) 1 h before LPS injection. Similarly to our previous report, SO1 increased survival after LPS injection. When rTM, which has different mechanisms of action, was combined with SO1, it did not interfere with the effect of SO1 and showed a significant increase in survival compared with LPS alone treatment. In serum, the combined treatment decreased NO levels. In the liver, the combined treatment inhibited iNOS mRNA and protein expression. A decreased iNOS AS transcript expression by the combined treatment was also observed. The combined treatment decreased mRNA expression of the inflammatory and pro-apoptotic genes while increasing that of the anti-apoptotic gene. Furthermore, the combined treatment reduced the number of myeloperoxidase-positive cells. These results suggested that the combination of SO1 and rTM has therapeutic potential for sepsis.

A novel miRNA mimic attenuates organ injury after hepatic ischemia/reperfusion

INTRODUCTION

Extracellular cold-inducible RNA-binding protein (eCIRP) is a novel mediator of inflammation and tissue injury. It has been shown that miRNA 130b-3p acts as an endogenous inhibitor of eCIRP. Because RNA mimics are unstable after in vivo administration, we have chemically engineered miRNA 130b-3p mimic (named PS-OMe miR130) to improve its stability by protection from nuclease activity. We hypothesize that PS-OMe miR130 reduces eCIRP-mediated injury and inflammation in a murine model of hepatic ischemia/reperfusion (I/R), a model of sterile inflammation.

METHODS

Adult male mice underwent 70% hepatic ischemia for 60 minutes and 24-hour reperfusion. At the start of reperfusion, mice were treated intravenously with vehicle (phosphate-buffered saline) or PS-OMe miR130. Blood and liver tissue were collected after 24 hours for biochemical analysis. Apoptosis in the liver tissue was determined by transferase dUTP nick-end labeling assay.

RESULTS

After hepatic I/R, organ injury markers including aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase significantly decreased after PS-OMe miR130 treatment. Furthermore, histological analysis of liver sections demonstrated significantly less injury in PS-OMe miR130 treatment mice versus vehicle mice. In addition, tumor necrosis factor α mRNA, interleukin-1β mRNA, and neutrophil infiltration (myeloperoxidase activity and granulocyte receptor 1 immunohistochemistry) were significantly attenuated after PS-OMe miR130 treatment. Finally, apoptosis significantly decreased in liver tissue after treatment.

CONCLUSION

PS-OMe miR130 decreases eCIRP-mediated injury and inflammation in a murine model of hepatic I/R.

Improvement of compliance to the Portland intensive insulin therapy during liver transplantation after introducing an application software: a retrospective single center cohort study

Background

The Portland intensive insulin therapy effectively controls acute hyperglycemic change after graft reperfusion during liver transplantation. However, the time-consuming sophistication acts as a barrier leading to misinterpretation and decreasing compliance to the protocol; thus, we newly introduced an application software “Insulin protocol calculator” which automatically calculates therapeutic bolus/continuous insulin doses based on the Portland protocol.

Methods

Of 144 patients who underwent liver transplantation, 74 patients were treated before the introduction of "Insulin protocol calculator" by using a paper manual, and 70 patients were treated by using the application. Compliance was defined as the proportion of patients treated with exact bolus/continuous insulin dose according to the Portland protocol.

Results

Compliance was significantly greater in app group than in paper group regarding bolus dose (94.5% and 86.9%, P < 0.001), continuous dose (88.9% and 77.3%, P = 0.001), and both doses (86.6% and 73.8%, P < 0.001). Blood glucose concentration was significantly lower in app group at 3 h (125 ± 17 mg/dl vs. 136 ± 19 mg/dl, P = 0.014) and 4 h (135 ± 22 mg/dl vs. 115 ± 15 mg/dl, P = 0.029) after graft reperfusion. Acute hyperglycemic change during 30 min was more prominent in app group while hyperglycemia incidence was 71.4% vs. 54.1% (P = 0.031). However, hyperglycemia risk was comparable at 2 h (31.4% vs. 31.1%, P = 0.964), and even insignificantly lower in app group at 3 h (7.1% vs. 19.5%, P = 0.184).

Conclusions

Compliance to the Portland protocol was significantly improved after introducing the application software; post-reperfusion hyperglycemia was better controlled. “Insulin protocol calculator” is cost-effective and time-saving with potential clinical benefits.

Two Compartment Evaluation of Liver Grafts During Acellular Room Temperature Machine Perfusion (acRTMP) in a Rat Liver Transplant Model

Background

Subnormothermic machine perfusion (SNMP) of liver grafts is currently less clinically developed than normothermic and hypothermic approaches, but may have logistical advantages. At intermediate temperatures, the oxygen demand of the graft is low enough to be satisfied with an acellular perfusate, obviating the need for oxygen carrying molecules. This intermediate metabolic rate, however, is sufficient to support the production of bile, which is emerging as an important indicator of graft injury and viability. In this study, we hypothesized that the biliary compartment would be more sensitive than perfusate in detecting graft injury during SNMP.

Methods

To test this hypothesis in a rat model, we performed liver transplants with DCD and control liver grafts after 1 h of acellular room temperature machine perfusion (acRTMP) or static cold storage (SCS). Point of care liver function tests were measured in biliary and perfusate samples after 1 h of machine perfusion. Following transplantation, rats were sacrificed at 24 h for assessment of post-transplant graft function and histology.

Results

All point-of-care liver function tests were significantly more concentrated in the biliary compartment than the perfusate compartment during acRTMP. DCD liver grafts could be distinguished from control liver grafts by significantly higher markers of hepatocyte injury (AST, ALT) in the biliary compartment, but not in the perfusate compartment. Classical markers of cholangiocyte injury, such as gammy-glut amyl transferase (GGT), amylase (AML), and alkaline phosphatase were detectable in the biliary compartment, but not in the perfusate compartment. In comparison to SCS, graft preservation by acRTMP produced a significant survival benefit in DCD liver transplantation (75 vs. 0%, p < 0.0030).

Conclusion

Together, these findings demonstrate that during acRTMP, the biliary compartment may be a more sensitive indicator of graft injury than the perfusate compartment. Moreover, acRTMP provides superior graft preservation to SCS in rat DCD liver transplantation.

Hyperglycemia-triggered ATF6-CHOP pathway aggravates acute inflammatory liver injury by β-catenin signaling

Although hyperglycemia has been documented as an unfavorable element that can further induce liver ischemia–reperfusion injury (IRI), the related molecular mechanisms remain to be clearly elaborated. This study investigated the effective manner of endoplasmic reticulum (ER) stress signaling in hyperglycemia-exacerbated liver IRI. Here we demonstrated that in the liver tissues and Kupffer cells (KCs) of DM patients and STZ-induced hyperglycemic mice, the ER stress-ATF6-CHOP signaling pathway is activated. TLR4-mediated pro-inflammatory activation was greatly attenuated by the addition of 4-phenylbutyrate (PBA), one common ER stress inhibitor. The liver IRI in hyperglycemic mice was also significantly reduced after PBA treatment. In addition, deficiency of CHOP (CHOP^−/−) obviously alleviates the hepatic IRI, and pro-inflammatory effects deteriorated by hyperglycemia. In hyperglycemic mice, β-catenin expression was suppressed while the ATF6-CHOP signal was activated. In the liver tissues of PBA-treated or CHOP^−/− hyperglycemic mice, the expression of β-catenin was restored. Furthermore, CHOP deficiency can induce protection against hyperglycemia-related liver IRI, which was disrupted by the knockdown of β-catenin will cause this protection to disappear. High glucose (HG) treatment stimulated ATF6-CHOP signaling, reduced cellular β-catenin accumulation, and promoted the TLR4-related inflammation of BMDMs. But the above effects were partially rescued in BMDMs with CHOP deficiency or by PBA treatment. In BMDMs cultured in HG conditions, the anti-inflammatory functions of CHOP^−/− were destroyed by the knockdown of β-catenin. Finally, chimeric mice carrying WT or CHOP^−/− BMDMs by bone marrow transplantation were adopted to verify the above conclusion. The current study suggested that hyperglycemia could trigger ER stress-ATF6-CHOP axis, inhibit β-catenin activation, accelerate inflammation, and deteriorate liver IRI, thus providing the treatment potential for management of sterile liver inflammation in DM patients.

Inhibition of the Interaction of TREM-1 and eCIRP Attenuates Inflammation and Improves Survival in Hepatic Ischemia/Reperfusion

INTRODUCTION

Triggering receptor expressed on myeloid cells-1 (TREM-1) has important implications in sepsis and inflammation and is a novel receptor for extracellular cold-inducible RNA-binding protein (eCIRP). We hypothesize that the inhibition of TREM-1 via its interaction with eCIRP by novel peptide inhibitor M3 or knockout gene will attenuate the inflammation and injury associated with severe hepatic ischemia/reperfusion (I/R).

METHODS

Wild-type (WT) C57BL/6 and TREM-1-/- mice underwent 60 min of 70% hepatic ischemia, with 24 h of reperfusion. Additionally, WT mice underwent hepatic I/R and were treated with M3 (10 mg/kg body weight) or vehicle (normal saline) at the start of reperfusion. Blood and ischemic liver tissues were collected, and analysis was performed using enzymatic assays, enzyme-linked immunosorbent assay, reverse-transcription quantitative polymerase chain reaction, and pathohistology techniques. For survival surgery, mice additionally underwent resection of non-ischemic lobes of the liver and survival was monitored for 10 days.

RESULTS

There was an increase in serum levels of tissue markers including aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase as well as cytokine levels (IL-6) and histological scoring of hematoxylin and eosin sections in WT I/R mice. These markers decreased substantially in TREM-1-/- mice. Additionally, neutrophil infiltration markers and markers of local inflammation (myeloperoxidase, macrophage inflammatory protein-2, cyclooxygenase-2) were attenuated in TREM-1-/- mice. Similarly, we show a significant decrease in injury and inflammation markers with M3 treatment. Additionally, we demonstrate decreased apoptosis with TREM-1 inhibition. Finally, M3 treatment improved the survival rate from 42% to 75% after hepatic I/R.

CONCLUSION

TREM-1 is an important eCIRP receptor in the inflammatory response of hepatic I/R, and deficiency of TREM-1 via knockout gene or peptide inhibition attenuated liver injury and inflammation, and improved survival. Inhibition of the TREM-1 and eCIRP interaction in hepatic I/R may have important therapeutic potential.

Near-infrared fluorescence imaging with indocyanine green for assessment of donor livers in a rat model of ischemia-reperfusion

BACKGROUND

Although marginal donor livers expand the donor pool, an ideal method for quantitatively evaluating the quality of donor livers has not been developed. This study aimed to explore the feasibility of indocyanine green (ICG) fluorescence imaging for estimating liver function in an ischemia-reperfusion model.

METHODS

Forty-eight rats were randomly and evenly divided into 8 groups: the control group and the experimental groups (I-VII). The portal vein blocking period was 0 min, 10 min, 20 min, 30 min, 40 min, 50 min and 60 min. After blood flow was reestablished and the hemodynamics stabilized, ICG was injected through the dorsal penile vein as a bolus, and the fluorescence signal was recorded for 30 min in real time. The fluorescence intensity (FI) curve of the liver was fitted with an asymptotic regression model. Fresh liver tissues and serum were obtained from the middle lobe of the liver on postoperative day (POD) 1 and POD 7 for histopathological evaluation and liver function tests.

RESULTS

The growth rate of the FI curve, parameter b3, decreased from groups I to VII. According to the two sudden changes in b3 (20 min, 50 min), the experimental groups could be classified into 3 groups (A, B and C). Hepatocytes in groups I-II showed slight edema, group III began to show obvious hepatocyte edema and vacuolar degeneration, and in groups VI-VII, severe hepatocyte degeneration, necrosis and large inflammatory cell infiltration were observed. Suzuki's scores in the 3 groups were also significantly different (P < 0.01). At the same time, the serum liver function in the experimental groups showed a significant increase on POD 1 and a decrease on POD 7. The alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TB) levels of groups A, B, and C were significantly different on POD 1 (P < 0.05), and the ALT and direct bilirubin (DB) levels were significantly different on POD 7 (P < 0.05); the lactic dehydrogenase (LDH) level of the group C was significantly higher than that of the groups A and B on POD 1 and POD 7. Meanwhile, the 7-day survival rate of the rats in group C was poor compared to that of the rats in groups A and B (58.3% vs. 100% vs. 100%).

CONCLUSION

ICG fluorescence imaging is effective for estimating the degree of liver damage and grading in an ischemia-reperfusion model. It probably has the potential for use in assessing the quality of the donor liver in liver transplantation.

Human adrenomedullin and its binding protein attenuate tissue injury and inflammation following hepatic ischemia reperfusion in rabbits

Background

Liver injury caused by ischemia reperfusion (I/R) during surgical procedures, such as liver resection or liver transplantation, is a major cause of liver damage and graft failure. The current method of treatment is mostly preventative (i.e., ischemic preconditioning). While a number of pharmacological modalities have been studied to reduce hepatic I/R injury, none have been entirely successful. It has been demonstrated that the administration of adrenomedullin (AM) in combination with AM-binding protein (AM/AMBP-1) exerts significant protective effects in various pathological conditions. In an effort to develop AM/AMBP-1 as a novel therapeutic for hepatic I/R injury, the present study examined the effect of a low dose of human AM, which does not induce hypotension, in combination with human AMBP-1 in a rabbit model of hepatic I/R (i.e., non-rodent species).

Methods

Ischemia of 70% of the liver was induced by placing a microvascular clip across the hilum of the left and median lobes for 60 min. The clip was then removed to commence reperfusion. At 15 min following clip removal (i.e., reperfusion), human AM/AMBP-1 was administered intravenously via the ear marginal vein continuously for 30 min. At 20 h, blood and tissue samples were collected for various measurements.

Results

The serum levels of liver enzymes (alanine aminotransferase and aspartate aminotransferase) and lactate dehydrogenase, were elevated following hepatic I/R. The administration of AM/AMBP-1 significantly decreased these levels by 58, 44, 41%, respectively. Hepatic I/R increased the direct and total bilirubin levels, whereas treatment with human AM/AMBP-1 decreased these levels by 60% and 69%, respectively. Treatment with AM/AMBP-1 also inhibited interleukin-6 gene expression by 95%. There were no changes in tumor necrosis factor-α (TNF-α) gene expression and myeloperoxidase activity (MPO), lactate and Suzuki scores after treatment. The treatment, however, reduced apoptosis post-hepatic I/R in the ischemic portion of the liver.

Conclusion

Additional experiments with AM and AMBP-1 alone are needed to completely interpret the experimental results in this non-rodent species of hepatic I/R injury. The present study suggests that human AM/AMBP-1 may be developed as a novel therapeutic to attenuate hepatic I/R associated inflammation and liver injury.

Impact of severe hypoglycemia on the heat shock and related protein response

Heat shock proteins contribute to diabetes-induced complications and are affected by glycemic control. Our hypothesis was that hypoglycemia-induced heat shock and related protein changes would be amplified in type 2 diabetes (T2D). This prospective, case-control study enrolled 23 T2D patients and 23 control subjects who underwent hyperinsulinemic-induced hypoglycemia (≤ 2.0 mmol/L (36 mg/dl)) with blood sampling at baseline, at hypoglycemia and after a 24-h post-hypoglycemia follow-up period. Proteomic analysis of heat shock-related and pro-inflammatory proteins was performed. At baseline, MAPKAPK5 (p = 0.02) and UBE2G2 (p = 0.003) were elevated and STUB1 decreased (p = 0.007) in T2D. At hypoglycemia: PPP3CA (p < 0.03) was increased and EPHA2 (p = 0.01) reduced in T2D; by contrast, three proteins were reduced in controls [HSPA1A (p = 0.007), HSPB1 (p < 0.02), SMAD3 (p = 0.005)] while only MAPKAPK5 was elevated (p = 0.02). In the post-hypoglycemia follow-up period, most proteins normalized to baseline by 24-h; however, STIP1 (p = 0.003), UBE2N (p = 0.004) and UBE2L3 (p < 0.04) were decreased in controls at 24-h. No protein differed from baseline at 24-h in T2D. Pro-inflammatory interleukin-6 increased at 4-h post-hypoglycemia in controls and T2D (p < 0.05 and p < 0.003, respectively) and correlated with HSPA1A; anti-inflammatory IL-10 decreased 2-h post-hypoglycemia in T2D only. Other pro-inflammatory proteins, IL-1α, IFN-γ and TNF-α, were unchanged. Heat shock and related proteins differed at baseline between T2D and controls, with an exaggerated response of heat shock and related proteins to hypoglycemia that returned to baseline, though with changes at 24-h in controls alone. An increase in pro-inflammatory IL-6, with a decrease in anti-inflammatory IL-10, suggests that the HSP system is overactivated due to underlying inflammation in T2D.Trial registration: ClinicalTrials.gov NCT03102801.

Nanozyme Impregnated Mesenchymal Stem Cells for Hepatic Ischemia-Reperfusion Injury Alleviation

Mesenchymal stem cell (MSC) based therapy holds great potential for treating numerous diseases owing to their capability to heal injured tissue/organs through paracrine factors secretion and immunomodulation. Despite the high hopes, the low viability of transplanted cells in the injured tissues due to the elevated oxidative stress levels remains the largest obstacle in MSC-based cell therapy. To achieve desired therapeutic efficiency, the survival of the transplanted MSCs in the high oxidative stress environment needs to be ensured. Herein, we proposed the use of a ROS-scavenging nanozyme to protect transplanted MSCs from oxidative stress-mediated apoptosis and thereby improve the therapeutic effect. Prussian blue (PB) nanoparticles as a biocompatible ROS-scavenging nanozyme were incorporated into the MSCs without affecting the stemness and differentiation potential of MSCs. The nanozyme impregnation significantly improved the survival of MSCs in a high oxidative stress condition as well as augmented their paracrine effect and anti-inflammatory properties, resulting in a profound therapeutic effect in vivo in the liver ischemia-reperfusion (I/R) injury animal model. Our results indicated that the nanozyme incorporation into MSCs is a simple but efficient way to improve the therapeutic potential of MSC-based cell therapy.

New Insights Into the Role of Autophagy in Liver Surgery in the Setting of Metabolic Syndrome and Related Diseases

Visceral obesity is an important component of metabolic syndrome, a cluster of diseases that also includes diabetes and insulin resistance. A combination of these metabolic disorders damages liver function, which manifests as non-alcoholic fatty liver disease (NAFLD). NAFLD is a common cause of abnormal liver function, and numerous studies have established the enormously deleterious role of hepatic steatosis in ischemia-reperfusion (I/R) injury that inevitably occurs in both liver resection and transplantation. Thus, steatotic livers exhibit a higher frequency of post-surgical complications after hepatectomy, and using liver grafts from donors with NAFLD is associated with an increased risk of post-surgical morbidity and mortality in the recipient. Diabetes, another MetS-related metabolic disorder, also worsens hepatic I/R injury, and similar to NAFLD, diabetes is associated with a poor prognosis after liver surgery. Due to the large increase in the prevalence of MetS, NAFLD, and diabetes, their association is frequent in the population and therefore, in patients requiring liver resection and in potential liver graft donors. This scenario requires advancement in therapies to improve postoperative results in patients suffering from metabolic diseases and undergoing liver surgery; and in this sense, the bases for designing therapeutic strategies are in-depth knowledge about the molecular signaling pathways underlying the effects of MetS-related diseases and I/R injury on liver tissue. A common denominator in all these diseases is autophagy. In fact, in the context of obesity, autophagy is profoundly diminished in hepatocytes and alters mitochondrial functions in the liver. In insulin resistance conditions, there is a suppression of autophagy in the liver, which is associated with the accumulation of lipids, being this is a risk factor for NAFLD. Also, oxidative stress occurring in hepatic I/R injury promotes autophagy. The present review aims to shed some light on the role of autophagy in livers undergoing surgery and also suffering from metabolic diseases, which may lead to the discovery of effective therapeutic targets that could be translated from laboratory to clinical practice, to improve postoperative results of liver surgeries when performed in the presence of one or more metabolic diseases.

Plasma heat shock protein response to euglycemia in type 2 diabetes

INTRODUCTION

Glucose variability is associated with mortality and macrovascular diabetes complications. The mechanisms through which glucose variability mediates tissue damage are not well understood, although cellular oxidative stress is likely involved. As heat shock proteins (HSPs) play a role in the pathogenesis of type 2 diabetes (T2D) complications and are rapidly responsive, we hypothesized that HSP-related proteins (HSPRPs) would differ in diabetes and may respond to glucose normalization.

RESEARCH DESIGN AND METHODS

A prospective, parallel study in T2D (n=23) and controls (n=23) was undertaken. T2D subjects underwent insulin-induced blood glucose normalization from baseline 7.6±0.4 mmol/L (136.8±7.2 mg/dL) to 4.5±0.07 mmol/L (81±1.2 mg/dL) for 1 hour. Control subjects were maintained at 4.9±0.1 mmol/L (88.2±1.8 mg/dL). Slow Off-rate Modified Aptamer-scan plasma protein measurement determined a panel of HSPRPs.

RESULTS

At baseline, E3-ubiquitin-protein ligase (carboxyl-terminus of Hsc70 interacting protein (CHIP) or HSPABP2) was lower (p=0.03) and ubiquitin-conjugating enzyme E2G2 higher (p=0.003) in T2D versus controls. Following glucose normalization, DnaJ homolog subfamily B member 1 (DNAJB1 or HSP40) was reduced (p=0.02) in T2D, with HSP beta-1 (HSPB1) and HSP-70-1A (HSP70-1A) (p=0.07 and p=0.09, respectively) also approaching significance relative to T2D baseline levels.

CONCLUSIONS

Key HSPRPs involved in critical protein interactions, CHIP and UBE2G2, were altered in diabetes at baseline. DNAJB1 fell in response to euglycemia, suggesting that HSPs are reacting to basal stress that could be mitigated by tight glucose control with reduction of glucose variability.

Exogenous melatonin alleviates hemorrhagic shock‑induced hepatic ischemic injury in rats by inhibiting the NF‑κB/IκBα signaling pathway

Melatonin (MT) is an indoleamine hormone that can counteract ischemia-induced organ injury through its antioxidant effects. The aim of the present study was to investigate the protective effects of exogenous MT against hemorrhagic shock (HS)-induced hepatic ischemic injury in rats, and the role of the nuclear factor (NF)-κB signaling pathway in this process. A rat model of HS-induced hepatic ischemic injury was established. The serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), glutamate dehydrogenase (GDH), tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-6 and IL-1β were measured every 6 h, and the 24-h survival rate of the rats was analyzed. All surviving rats were sacrificed after 24 h. Pathological changes in the liver and the hepatocyte apoptosis rate were observed by hematoxylin and eosin staining and TUNEL assay, respectively, and the expression levels of NF-κB p65 and NF-κB inhibitor α (IκBα) were analyzed by reverse transcription-quantitative PCR analysis and western blotting. The results demonstrated that the serum levels of ALT, AST, LDH, GDH, TNF-α, IFN-γ, IL-6 and IL-1β gradually increased after HS compared with those in rats subjected to a sham procedure, but this increase was attenuated by MT. Furthermore, the survival rate of the MT group was significantly higher compared with that of the HS group. The degree of pathological hepatic injury, the hepatocyte apoptosis rate, and the hepatic levels of TNF-α, IFN-γ, IL-6 and IL-1β were significantly decreased in the MT group compared with the HS group. In addition, the mRNA expression of NF-κB p65 was significantly decreased and the mRNA expression of IκBα was significantly increased in the MT group compared with the sham group. Furthermore, the NF-κB p65 protein levels in the MT group were significantly increased in the cytosol but decreased in the nucleus, and the IκBα protein levels were increased while those of phosphorylated IκBα were decreased compared with those in the HS group. Therefore, it may be inferred that exogenous MT alleviates HS-induced hepatic ischemic injury in rats via the inhibition of NF-κB activation and IκBα phosphorylation.

Endothelium-dependent remote signaling in ischemia and reperfusion: Alterations in the cardiometabolic continuum

Intact endothelial function plays a fundamental role for the maintenance of cardiovascular (CV) health. The endothelium is also involved in remote signaling pathway-mediated protection against ischemia/reperfusion (I/R) injury. However, the transfer of these protective signals into clinical practice has been hampered by the complex metabolic alterations frequently observed in the cardiometabolic continuum, which affect redox balance and inflammatory pathways. Despite recent advances in determining the distinct roles of hyperglycemia, insulin resistance (InR), hyperinsulinemia, and ultimately diabetes mellitus (DM), which define the cardiometabolic continuum, our understanding of how these conditions modulate endothelial signaling remains challenging. It is widely accepted that endothelial cells (ECs) undergo functional changes within the cardiometabolic continuum. Beyond vascular tone and platelet-endothelium interaction, endothelial dysfunction may have profound negative effects on outcome during I/R. In this review, we summarize the current knowledge of the influence of hyperglycemia, InR, hyperinsulinemia, and DM on endothelial function and redox balance, their influence on remote protective signaling pathways, and their impact on potential therapeutic strategies to optimize protective heterocellular signaling.

Transcriptional changes during hepatic ischemia-reperfusion in the rat

There are few effective targeted strategies to reduce hepatic ischemia-reperfusion (IR) injury, a contributor to poor outcomes in liver transplantation recipients. It has been proposed that IR injury is driven by the generation of reactive oxygen species (ROS). However, recent studies implicate other mediators of the injury response, including mitochondrial metabolic dysfunction. We examined changes in global gene expression after transient hepatic ischemia and at several early reperfusion times to identify potential targets that could be used to protect against IR injury. Male Wistar rats were subjected to 30 minutes of 70% partial warm ischemia followed by 0, 0.5, 2, or 6 hours of reperfusion. RNA was extracted from the reperfused and non-ischemic lobes at each time point for microarray analysis. Identification of differentially expressed genes and pathway analysis were used to characterize IR-induced changes in the hepatic transcriptome. Changes in the reperfused lobes were specific to the various reperfusion times. We made the unexpected observation that many of these changes were also present in tissue from the paired non-ischemic lobes. However, the earliest reperfusion time, 30 minutes, showed a marked increase in the expression of a set of immediate-early genes (c-Fos, c-Jun, Atf3, Egr1) that was exclusive to the reperfused lobe. We interpreted these results as indicating that this early response represented a tissue autonomous response to reperfusion. In contrast, the changes that occurred in both the reperfused and non-ischemic lobes were interpreted as indicating a non-autonomous response resulting from hemodynamic changes and/or circulating factors. These tissue autonomous and non-autonomous responses may serve as targets to ameliorate IR injury.

Postoperative hyperglycemia may negatively impact cytomegalovirus infection in seropositive liver transplant recipients: a retrospective cohort study

The aim of the study was to evaluate the association between postoperative hyperglycemia and CMV infection. We analyzed 741 CMV seropositive recipients, of livers from seropositive living donors, who underwent preemptive CMV treatment without CMV prophylaxis. The primary outcome was early CMV infection within 1 month after surgery. Hyperglycemia was defined when mean postoperative blood glucose concentration was >180 mg/dl based on previous research and guidelines. Survival analysis was performed using the Fine and Gray model by accounting for the competing risk of CMV infection-unrelated death. Of the 741 recipients (hyperglycemic group, n = 287; nonhyperglycemic group, n = 454), 372 (50.2%) recipients developed cytomegalovirus (CMV) infection within 1 month after surgery. CMV infection risk was significantly higher in hyperglycemic group than in nonhyperglycemic group in univariable analysis [hazard ratio (HR) 1.34, 95% confidence interval (CI), 1.08-1.66; P = 0.007] and in multivariable analysis (HR 1.25, 95% CI 1.0-1.54; P = 0.038). CMV infection risk was also significantly associated with recipient age, graft ischemia time, model for end-stage liver disease score, and preoperative neutrophil-to-lymphocyte ratio (P < 0.05). In conclusion, preventing postoperative hyperglycemia appears to be an important factor decreasing the risk of CMV infection in seropositive liver transplant recipients undergoing preemptive CMV treatment.

Insulin therapy in organ donation and transplantation

Hyperglycaemia is common in hospitalized individuals, and is often caused by physiological stress associated with critical illness or major surgery. Insulin therapy is an established treatment for hyperglycaemia and acute hyperkalaemia, and has also been used for myocardial dysfunction resistant to inotropic support. Insulin is commonly used in both organ donors and transplant recipients for hyperglycaemia, but the underlying knowledge base supporting its use remains limited. Insulin therapy plays an important yet poorly understood role in both organ donation and transplantation. Tight glycaemic control has been extensively studied in critical care over the past 15 years; however, this has not yet translated into the field of transplantation, where patients are more unwell and where improved outcomes remain an ongoing challenge. Insulin therapy and optimization of glycaemic control represent important areas for future hypothesis-driven research into organ donation and transplantation, such as amelioration of ischaemia-reperfusion injury, rejection and infection.

Hyperglycemia-Triggered Sphingosine-1-Phosphate and Sphingosine-1-Phosphate Receptor 3 Signaling Worsens Liver Ischemia/Reperfusion Injury by Regulating M1/M2 Polarization

Hyperglycemia aggravates hepatic ischemia/reperfusion injury (IRI), but the underlying mechanism for the aggravation remains elusive. Sphingosine-1-phosphate (S1P) and sphingosine-1-phosphate receptors (S1PRs) have been implicated in metabolic and inflammatory diseases. Here, we discuss whether and how S1P/S1PRs are involved in hyperglycemia-related liver IRI. For our in vivo experiment, we enrolled diabetic patients with benign hepatic disease who had liver resection, and we used streptozotocin (STZ)-induced hyperglycemic mice or normal mice to establish a liver IRI model. In vitro bone marrow-derived macrophages (BMDMs) were differentiated in high-glucose (HG; 30 mM) or low-glucose (LG; 5 mM) conditions for 7 days. The expression of S1P/S1PRs was analyzed in the liver and BMDMs. We investigated the functional and molecular mechanisms by which S1P/S1PRs may influence hyperglycemia-related liver IRI. S1P levels were higher in liver tissues from patients with diabetes mellitus and mice with STZ-induced diabetes. S1PR3, but not S1PR1 or S1PR2, was activated in liver tissues and Kupffer cells under hyperglycemic conditions. The S1PR3 antagonist CAY10444 attenuated hyperglycemia-related liver IRI based on hepatic biochemistry, histology, and inflammatory responses. Diabetic livers expressed higher levels of M1 markers but lower levels of M2 markers at baseline and after ischemia/reperfusion. Dual-immunofluorescence staining showed that hyperglycemia promoted M1 (CD68/CD86) differentiation and inhibited M2 (CD68/CD206) differentiation. Importantly, CAY10444 reversed hyperglycemia-modulated M1/M2 polarization. HG concentrations in vitro also triggered S1P/S1PR3 signaling, promoted M1 polarization, inhibited M2 polarization, and enhanced inflammatory responses compared with LG concentrations in BMDMs. In contrast, S1PR3 knockdown significantly retrieved hyperglycemia-modulated M1/M2 polarization and attenuated inflammation. In conclusion, our study reveals that hyperglycemia specifically triggers S1P/S1PR3 signaling and exacerbates liver IRI by facilitating M1 polarization and inhibiting M2 polarization, which may represent an effective therapeutic strategy for liver IRI in diabetes.

Portland Intensive Insulin Therapy During Living Donor Liver Transplantation: Association with Postreperfusion Hyperglycemia and Clinical Outcomes

Many liver transplant recipients experience intraoperative hyperglycemia after graft reperfusion. Accordingly, we introduced the Portland intensive insulin therapy (PoIIT) in our practice to better control blood glucose concentration (BGC). We evaluated the effects of PoIIT by comparing with our conventional insulin therapy (CoIT). Of 128 patients who underwent living donor liver transplantation (LDLT) during the phaseout period of CoIT, 89 were treated with the PoIIT and 39 were treated with CoIT. The primary outcome was hyperglycemia (BGC > 180 mg/dL) during the intraoperative postreperfusion phase. The secondary outcomes were postoperative complications such as infection. The incidence of hyperglycemia (22.5% vs. 53.8%, p = 0.001) and prolonged hyperglycemia for >2 hours (7.9% vs. 30.8%, p = 0.002) was significantly lower in PoIIT group than in CoIT group. A mixed linear model further demonstrated that repeatedly measured BGCs were lower in PoIIT group (p < 0.001). The use of PoIIT was significantly associated with decreases in major infections (OR = 0.23 [0.06-0.85], p = 0.028), prolonged mechanical ventilation (OR = 0.29 [0.09-0.89], p = 0.031), and biliary stricture (OR = 0.23 [0.07-0.78], p = 0.018) after adjustments for age, sex, and diabetes mellitus. In conclusion, the PoIIT is effective for maintaining BGC and preventing hyperglycemia during the intraoperative postreperfusion phase of living donor liver transplantation with potential clinical benefits.

cGAS-mediated autophagy protects the liver from ischemia-reperfusion injury independently of STING

Liver ischemia-reperfusion (I/R) injury occurs through induction of oxidative stress and release of damage-associated molecular patterns (DAMPs), including cytosolic DNA released from dysfunctional mitochondria or from the nucleus. Cyclic guanosine monophosphate-adenosine monophosphate (cGAMP) synthase (cGAS) is a cytosolic DNA sensor known to trigger stimulator of interferon genes (STING) and downstream type 1 interferon (IFN-I) pathways, which are pivotal innate immune system responses to pathogen. However, little is known about the role of cGAS/STING in liver I/R injury. We subjected C57BL/6 (WT), cGAS knockout (cGAS^-/-), and STING-deficient (STING^gt/gt) mice to warm liver I/R injury and that found cGAS^-/- mice had significantly increased liver injury compared with WT or STING^gt/gt mice, suggesting a protective effect of cGAS independent of STING. Liver I/R upregulated cGAS in vivo and also in vitro in hepatocytes subjected to anoxia/reoxygenation (A/R). We confirmed a previously published finding that hepatocytes do not express STING under normoxic conditions or after A/R. Hepatocytes and liver from cGAS^-/- mice had increased cell death and reduced induction of autophagy under hypoxic conditions as well as increased apoptosis. Protection could be restored in cGAS^-/- hepatocytes by overexpression of cGAS or by pretreatment of mice with autophagy inducer rapamycin. Our findings indicate a novel protective role for cGAS in the regulation of autophagy during liver I/R injury that occurs independently of STING. NEW & NOTEWORTHY Our studies are the first to document the important role of cGAS in the acute setting of sterile injury induced by I/R. Specifically, we provide evidence that cGAS protects liver from I/R injury in a STING-independent manner.

Diabetes Mellitus and Liver Surgery: The Effect of Diabetes on Oxidative Stress and Inflammation

Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycaemia and high morbidity worldwide. The detrimental effects of hyperglycaemia include an increase in the oxidative stress (OS) response and an enhanced inflammatory response. DM compromises the ability of the liver to regenerate and is particularly associated with poor prognosis after ischaemia-reperfusion (I/R) injury. Considering the growing need for knowledge of the impact of DM on the liver following a surgical procedure, this review aims to present recent publications addressing the effects of DM (hyperglycaemia) on OS and the inflammatory process, which play an essential role in I/R injury and impaired hepatic regeneration after liver surgery.

Investigation of chronic efficacy and safety profile of two potential anti-inflammatory bipyrazole-based compounds in experimental animals

Purpose

Although nonsteroidal anti-inflammatory drugs are widely used to treat a variety of disorders, their administration is associated with gastrointestinal side effects, acute kidney injury and liver enzymes’ elevation. Accordingly, researchers are encouraged to create novel agents with better safety profile. The aim of the current study was to evaluate the chronic efficacy and safety profile of two compounds previously proven to have acceptable acute anti-inflammatory and analgesic activities.

Materials and methods

Doses were determined through formalin-induced mice paw edema-based dose–response curves. Granuloma weight was used to assess the chronic effect of the investigated compounds as compared to the vehicle and diclofenac representing the positive and the negative controls, respectively. Mice kidneys, livers and stomachs were histologically examined. Moreover, troponin I, alanine aminotransferase, aspartate aminotransferase, serum creatinine and blood urea nitrogen levels were measured.

Results

The results highlight that the granulomas and exudates developed in mice after 7 days of treatment, with compound I and compound II were significantly lower than that of the negative control group. Moreover, compound I showed significantly better anti-inflammatory effect than diclofenac. Troponin level was undetected in all groups. Histopathological examination of the stomach revealed normal mucosa for both tested compounds and controls. Likewise, kidneys showed neither significant histologic alteration nor biomarkers increase as compared to the control over both 7- and 30-day treatment periods. Mice that received the tested compounds or diclofenac exhibited transient liver damage specifically; congestion, vacuolization, necrosis and inflammation after 7 days of treatment which decreased significantly after 30 days of treatment as emphasized by the Suzuki score and biomarker levels.

Conclusion

Since the tested compounds, specifically compound I, presented a satisfactory chronic safety profile as well as anti-inflammatory effect, it is worth conducting further molecular pharmacological, toxicological and bioavailability studies to elucidate the efficacy of these potential anti-inflammatory bipyrazole compounds.

Cerebral Ischemia-Reperfusion Injuries in Vanadyl-Treated Diabetic Rats

BACKGROUND

Ischemic stroke recovery is poor in diabetic mellitus (DM). Vanadium compounds (vanadium) relieve DM signs, but their influences on cerebral ischemia/reperfusion injury (I/RI) are inconclusive. Herein, the intensity of I/RI was inspected in vanadium-treated DM rats.

METHODS

Rats made diabetic with a single intravenous dose of streptozocin (39 mg/kg). Normal and DM rats used water or vanadyl solution for 45 days. Under isoflurane anesthesia, right middle cerebral artery occlusion was performed for 60 minutes and 12 hours reperfusion. Ischemic rats were divided into untreated-control normal (ICN) and diabetic (ICD), vanadium-treated normal (IVTN) and diabetic (IVTD) groups (n=14 each). After neurological deficit score (NDS) test, the rats were sacrificed and their brain removed and stained with triphenyltetrazolium chloride (TTC) to measure cerebral infarct volume (CIV, mm³) or Evans blue extravasation (EBE, μg/g wet-tissue). Data analysis was performed using one-way ANOVA and Tukey's test (SPSS software, version 21.0) and P values <0.05 were considered statistically significant.

RESULTS

Blood glucose (BG, mg/dL) was similar in ICN and IVTN, elevated in IVTD and ICD (245±6 vs. 344±2, P<0.001). The increased CIV in ICN and IVTN was similar (48±2 and 34±5), very high in ICD but lower in IVTD (249±37 vs. 110±16, P<0.001). EBE was absent in non-lesioned hemispheres, similarly increased in lesioned hemispheres of ICN and IVTN (14±1 and 13±1). EBE in IVTD was significantly lower than ICD (21±2 vs. 33±5, P=0.01).

CONCLUSION

I/RI was moderate in normoglycemia and did not change with vanadium. Hyperglycemia robustly intensified I/RI. Vanadium ameliorated hyperglycemia and reduced I/RI. Nonetheless, more investigations are required to link the mechanisms of vanadium on DM and stroke injuries.

Hyperglycemia Aggravates Hepatic Ischemia and Reperfusion Injury by Inhibiting Liver-Resident Macrophage M2 Polarization via C/EBP Homologous Protein-Mediated Endoplasmic Reticulum Stress

Aggravated liver ischemia and reperfusion (IR) injury has been observed in hyperglycemic hosts, but its underlying mechanism remains undefined. Liver-resident macrophages (Kupffer cells, KCs) and endoplasmic reticulum (ER) stress play crucial roles in the pathogenesis of liver IR injury. In this study, we evaluated the role of ER stress in regulating KC activation and liver IR injury in a streptozotocin-induced hyperglycemic/diabetic mouse model. Compared to the control group (CON group), hyperglycemic mice exhibited a significant increase in liver injury and intrahepatic inflammation following IR. KCs obtained from hyperglycemic mice secreted higher levels of the pro-inflammatory factors TNF-α and IL-6, while they secreted significantly lower levels of the anti-inflammatory factor IL-10. Furthermore, enhanced ER stress was revealed by increased C/EBP homologous protein (CHOP) activation in both IR-stressed livers and KCs from hyperglycemic mice. Specific CHOP knockdown in KCs by siRNA resulted in a slight decrease in TNF-α and IL-6 secretion but dramatically enhanced anti-inflammatory IL-10 secretion in the hyperglycemic group, while no significant changes in cytokine production were observed in the CON group. We also analyzed the role of hyperglycemia in macrophage M1/M2 polarization. Interestingly, we found that hyperglycemia inhibited IL-10-secreting M2-like macrophage polarization, as revealed by decreased Arg1 and Mrc1 gene induction accompanied by a decrease in STAT3 and STAT6 signaling pathway activation. CHOP knockdown restored Arg1 and Mrc1 gene induction, STAT3 and STAT6 activation, and most importantly, IL-10 secretion in hyperglycemic KCs. Finally, in vivo CHOP knockdown in KCs enhanced intrahepatic anti-inflammatory IL-10 gene induction and protected the liver against IR injury in hyperglycemic mice but had no significant effects in control mice. Our results demonstrate that hyperglycemia induces hyper-inflammatory activation of KCs during liver IR injury. Thus, hyperglycemia-induced CHOP over-activation inhibits IL-10-secreting M2-like macrophage polarization by liver-resident macrophages, thereby leading to excessive inflammation and the exacerbation of liver IR injury in diabetic/hyperglycemic hosts. This study provides novel mechanistic insight into macrophage inflammatory activation under hyperglycemic conditions during liver IR.

Prognostic Impact of Combined Dysglycemia and Hypoxic Liver Injury on Admission in Patients With ST-Segment Elevation Myocardial Infarction Who Underwent Primary Percutaneous Coronary Intervention (from the INTERSTELLAR Cohort)

Dysglycemia on admission is known to predict the prognosis of ST-segment elevation myocardial infarction (STEMI). Recently, hypoxic liver injury (HLI) has been proposed as a novel prognosticator for STEMI. We evaluated the prognostic impact of combined dysglycemia and HLI at the time of presentation in patients with STEMI who underwent primary percutaneous coronary intervention. From 2007 to 2014, 1,525 consecutive patients (79% men, mean age 61 years) who underwent primary percutaneous coronary intervention for STEMI in the INTERSTELLAR (Incheon-Bucheon Cohort of Patients Undergoing Primary PCI for Acute ST-Elevation Myocardial Infarction) cohort were analyzed retrospectively. Dysglycemia was defined as either hypoglycemia (serum glucose <90 mg/dl) or hyperglycemia (serum glucose >250 mg/dl). HLI was defined as more than twofold increase of any serum aminotransferases above the upper normal limit. Patients were divided into 4 groups according to their dysglycemia and HLI status on admission: group 1, normoglycemia without HLI; group 2, dysglycemia without HLI; group 3, normoglycemia with HLI; and group 4, dysglycemia with HLI. Primary end point was inhospital death and secondary end point was all-cause mortality at 12 months after the index procedure. Of the 1,525 patients, there were 87 inhospital deaths (5.7%) and 113 all-cause deaths (7.4%) at 12 months after the index procedure. Both dysglycemia and HLI on admission were independent predictors of inhospital death. Inhospital mortality rate was the highest in group 4 (32.1%), followed by groups 2 and 3. Kaplan-Meier survival analysis at 12 months showed similar trends among the 4 groups. In conclusion, combined dysglycemia and HLI on admission predicts early prognosis for STEMI.

Hyperglycemia Aggravates Hepatic Ischemia Reperfusion Injury by Inducing Chronic Oxidative Stress and Inflammation

Aim. To investigate whether hyperglycemia will aggravate hepatic ischemia reperfusion injury (HIRI) and the underlying mechanisms. Methods. Control and streptozotocin-induced diabetic Sprague-Dawley rats were subjected to partial hepatic ischemia reperfusion. Liver histology, transferase, inflammatory cytokines, and oxidative stress were assessed accordingly. Similarly, BRL-3A hepatocytes were subjected to hypoxia/reoxygenation (H/R) after high (25 mM) or low (5.5 mM) glucose culture. Cell viability, reactive oxygen species (ROS), and activation of nuclear factor-erythroid 2-related factor 2 (Nrf2) and nuclear factor of kappa light polypeptide gene enhancer in B-cells (NF-κB) were determined. Results. Compared with control, diabetic rats presented more severe hepatic injury and increased hepatic inflammatory cytokines and oxidative stress. HIRI in diabetic rats could be ameliorated by pretreatment of N-acetyl-L-cysteine (NAC) or apocynin. Excessive ROS generation and consequent Nrf2 and NF-κB translocation were determined after high glucose exposure. NF-κB translocation and its downstream cytokines were further increased in high glucose cultured group after H/R. While proper regulation of Nrf2 to its downstream antioxidases was observed in low glucose cultured group, no further induction of Nrf2 pathway by H/R after high glucose culture was identified. Conclusion. Hyperglycemia aggravates HIRI, which might be attributed to chronic oxidative stress and inflammation and potential malfunction of antioxidative system.

Association between Serum Bilirubin and Acute Intraoperative Hyperglycemia Induced by Prolonged Intermittent Hepatic Inflow Occlusion in Living Liver Donors

Background

Intermittent hepatic inflow occlusion (IHIO) is associated with acute hyperglycemia during living donor hepatectomy when the ischemia is prolonged. Bilirubin is a potent antioxidant to play an important role for maintaining insulin sensitivity and preventing hyperglycemia. Thus, we aimed to test whether serum bilirubin level is associated with prolonged IHIO-induced intraoperative hyperglycemia.

Methods

Seventy-five living liver donors who underwent a prolonged IHIO with a >30 minute cumulative ischemia were included. The association between preoperative serum bilirubin concentrations and the risk of intraoperative hyperglycemia (blood glucose concentration >180 mg/dl) was analyzed using binary logistic regression with adjusting for potential confounders including age and steatosis.

Results

The number of donors who underwent 3, 4, 5, and 6 rounds of IHIO was 41, 22, 7, and 5, respectively. Twenty-nine (35%) donors developed intraoperative hyperglycemia. Total bilirubin concentration was inversely associated with hyperglycemia risk (odds ratio [OR] 0.033, 95% confidence interval [CI] 0.004–0.313, P = 0.003). There was an interaction between age and total bilirubin concentration: the effect of lower serum total bilirubin (≤0.7 mg/dl) on the development of hyperglycemia was greater in older donors (>40 years) than in younger donors (P = 0.0.028 versus P = 0.212). Both conjugated bilirubin (OR 0.001 95% CI 0.001–0.684) and unconjugated bilirubin (OR 0.011 95% CI 0.001–0.246) showed an independent association with hyperglycemia risk.

Conclusions

Lower preoperative serum bilirubin was associated with greater risk of prolonged IHIO-induced hyperglycemia during living donor hepatectomy particularly in older donors. Thus, more meticulous glycemic management is recommended when prolonged IHIO is necessary for surgical purposes in old living donors with lower serum bilirubin levels.

Hyperglycemia and liver ischemia reperfusion injury: a role for the advanced glycation endproduct and its receptor pathway

Although pretransplant diabetes is a risk factor for mortality post-liver transplant, the underlying mechanism has not been fully defined. In a murine liver partial warm ischemia model, we addressed the question of how diabetes/hyperglycemia impacted tissue inflammatory injuries against ischemia reperfusion (IR), focusing on the advanced glycation endproduct (AGE) and its receptor (RAGE) pathway. Our results showed that hepatocellular injury was exacerbated in streptozotocin-induced diabetic mice against IR, in association with hyper-inflammatory immune activation in livers. Serum levels of AGEs, but not HMGB1, were increased in diabetic mice in response to liver IR. Both RAGE antagonist peptides and small interfering RNA alleviated liver injuries and inhibited inflammatory immune activation against IR in diabetic, but not normal, mice. Kupffer cells (KCs)/macrophages, but not hepatocytes, from diabetic mice expressed significantly higher levels of RAGE, leading to their hyper-inflammatory responsiveness to both TLR ligands and AGEs. In vitro, hyperglycemia increased macrophage RAGE expression and enhanced their TLR responses. Our results demonstrated that activation of the AGE-RAGE signaling pathway in KCs was responsible for hyper-inflammatory immune responses and exacerbated hepatocellular injuries in diabetic/hyperglycemic hosts against liver IR.

Randomized phase 3 trial of ombitasvir/paritaprevir/ritonavir for hepatitis C virus genotype 1b-infected Japanese patients with or without cirrhosis

GIFT-I is a phase 3 trial evaluating the efficacy and safety of a 12-week regimen of coformulated ombitasvir (OBV)/paritaprevir (PTV)/ritonavir (r) for treatment of Japanese hepatitis C virus genotype 1b-infected patients. It consists of a double-blind, placebo-controlled substudy of patients without cirrhosis and an open-label substudy of patients with compensated cirrhosis. Patients without cirrhosis were randomized 2:1 to once-daily OBV/PTV/r (25 mg/150 mg/100 mg; group A) or placebo (group B). Patients with cirrhosis received open-label OBV/PTV/r (group C). The primary efficacy endpoint was the rate of sustained virological response 12 weeks posttreatment in interferon-eligible, treatment-naive patients without cirrhosis and hepatitis C virus RNA ≥100,000 IU/mL in group A. A total of 321 patients without cirrhosis were randomized and dosed with double-blind study drug (106 received double-blind placebo and later received open-label OBV/PTV/r), and 42 patients with cirrhosis were enrolled and dosed with open-label OBV/PTV/r. In the primary efficacy population, the rate of sustained virological response 12 weeks posttreatment was 94.6% (106/112, 95% confidence interval 90.5-98.8). Sustained virological response 12 weeks posttreatment rates were 94.9% (204/215) in group A, 98.1% (104/106) in group B (open-label), and 90.5% (38/42) in group C. Overall, virological failure occurred in 3.0% (11/363) of patients who received OBV/PTV/r. The rate of discontinuation due to adverse events was 0%-2.4% in the three patient groups receiving OBV/PTV/r. The most frequent adverse event in patients in any group was nasopharyngitis.

CONCLUSION

In this broad hepatitis C virus genotype 1b-infected Japanese patient population with or without cirrhosis, treatment with OBV/PTV/r for 12 weeks was highly effective and demonstrated a favorable safety profile.

Blocking cold-inducible RNA-binding protein protects liver from ischemia-reperfusion injury

Cold-inducible RNA-binding protein (CIRP) is a nuclear protein that has been recently identified as a novel inflammatory mediator in hemorrhagic shock and sepsis. We hypothesized that CIRP acts as a potent inflammatory mediator in hepatic ischemia-reperfusion (I/R), and thus blocking CIRP protects against I/R-induced liver injury. Male C57BL/6 mice were subjected to 70% hepatic ischemia by microvascular clamping of the hilum of the left and median liver lobes for 60 min, followed by reperfusion. Anti-CIRP antibody (1 mg/kg body weight) or vehicle (normal saline) in 0.2 mL was injected via the internal jugular vein at the beginning of the reperfusion. Blood and liver tissues were collected 24 h after I/R for various measurements, and a 10-day survival study was performed. Cold-inducible RNA-binding protein released into the circulation was significantly increased 24 h after hepatic I/R. Anti-CIRP antibody treatment markedly reduced hepatocellular damage markers and significantly improved the liver microarchitecture. Anti-CIRP also reduced the systemic and local inflammation demonstrated by attenuation in both serum and hepatic levels of interleukin 6. The expression of neutrophil-attracting chemokine as well as liver neutrophil infiltration was reduced by anti-CIRP treatment. Anti-CIRP also dramatically decreased the amount of apoptosis and nitrosative stress, evidenced by decrease in TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) staining and inducible nitric oxide synthase and cyclooxygenase 2 levels, respectively. Finally, the 10-day survival rate was increased from 37.5% in the vehicle group to 75% in the anti-CIRP treatment group. Thus, targeting CIRP offers potential therapeutic implications in the treatment of hepatic I/R injury.

Farnesyltransferase inhibitor, tipifarnib, prevents galactosamine/lipopolysaccharide-induced acute liver failure

Acute liver failure (ALF) is a fatal syndrome associated with massive hepatocyte death. There is no cure for ALF except liver transplantation. Protein farnesylation is a lipid modification of cysteine residues that is catalyzed by farnesyltransferase (FTase) and has been proposed as an integral component of acute inflammation. Previously, we have demonstrated that FTase inhibitors improve survival in mouse models of endotoxemia and sepsis. Here we studied the effects of FTase inhibitor, tipifarnib, on galactosamine (GalN)/lipopolysaccharide (LPS)-induced ALF. The effects of tipifarnib (10 mg/kg, i.p.) were studied in GalN (400 mg/kg, i.p.)- and LPS (3 μg/kg)-challenged mice by histological and biochemical analyses. Galactosamine/LPS administration caused prominent liver injury characterized by the increased plasma alanine aminotransferase and aspartic aminotransferase levels, leading to significant mortality in mice. Tipifarnib inhibited GalN/LPS-induced caspase 3 activation, inflammatory cytokine production, and c-Jun N-terminal kinase phosphorylation in the liver. On the other hand, tipifarnib upregulated antiapoptotic protein, Bcl-xL, in the liver after GalN/LPS challenge. Tipifarnib also protected primary hepatocytes from GalN/tumor necrosis factor α-induced cell death by inhibiting caspase 3 activation and upregulating antiapoptotic proteins. Galactosamine/LPS-induced liver injury was associated with increased protein farnesylation in the liver. Tipifarnib prevented protein farnesylation in the liver and markedly attenuated liver injury and mortality in GalN/LPS-challenged mice. These results suggest that protein farnesylation is a novel potential molecular target to prevent hepatocyte death and acute inflammatory liver failure in fulminant hepatitis.

Macrosteatotic and nonmacrosteatotic grafts respond differently to intermittent hepatic inflow occlusion: Comparison of recipient survival

Intermittent hepatic inflow occlusion (IHIO) during liver graft procurement is known to confer protection against graft ischemia/reperfusion injury and thus may benefit the recipient's outcome. We evaluated whether the protective effect of IHIO differs with the presence of macrosteatosis (MaS) and with an increase or decrease in the cumulative occlusion time. The subgroup of 188 recipients who received grafts with MaS was divided into 3 groups according to the number of total IHIO rounds during graft procurement: no IHIO, n = 70; 1 to 2 rounds of IHIO, n = 50; and ≥3 rounds of IHIO, n = 68. Likewise, the subgroup of 200 recipients who received grafts without MaS was divided into 3 groups: no IHIO, n = 108; 1 to 2 rounds of IHIO, n = 40; and ≥3 rounds of IHIO, n = 52. The Cox model was applied to evaluate the association between the number of total IHIO rounds and recipient survival separately in the subgroup of MaS recipients and the subgroup of non-MaS recipients. Analyzed covariables included the etiology, Milan criteria, transfusion, immunosuppression, and others. In the subgroup of MaS recipients, 1 to 2 rounds of IHIO were favorably associated with recipient survival [hazard ratio (HR), 0.29; 95% confidence interval (CI), 0.10-0.80; P = 0.03 after Bonferroni correction], whereas ≥3 rounds of IHIO were not associated with recipient survival (HR, 0.56; 95% CI, 0.25-1.23). In the subgroup of non-MaS recipients, neither 1 to 2 rounds of IHIO (HR, 0.69; 95% CI, 0.30-1.61) nor ≥3 rounds of IHIO (HR, 0.91; 95% CI, 0.42-1.96) were associated with recipient survival. In conclusion, 1 to 2 rounds of IHIO may be used for the procurement of MaS grafts with potential benefit for recipient survival, whereas IHIO has a limited impact on recipient survival regardless of the cumulative occlusion time when it is used for non-MaS grafts.

Glycemic responses to intermittent hepatic inflow occlusion in living liver donors

The occurrence of glycemic disturbances has been described for patients undergoing intermittent hepatic inflow occlusion (IHIO) for tumor removal. However, the glycemic responses to IHIO in living liver donors are unknown. This study investigated the glycemic response to IHIO in these patients and examined the association between this procedure and the occurrence of hyperglycemia (blood glucose > 180 mg/dL). The data from 154 living donors were retrospectively reviewed. The decision to perform IHIO was made on the basis of the extent of bleeding that occurred during parenchymal dissection. One round of IHIO consisted of 15 minutes of clamping and 5 minutes of unclamping the hepatic artery and portal vein. Blood glucose concentrations were measured at predetermined time points, including the start and end of IHIO. Repeated hyperglycemic episodes occurred after unclamping. The mean maximum intraoperative blood glucose concentration was greater in donors who underwent ≥3 rounds of IHIO versus those who underwent 1 or 2 rounds (169 ± 30 versus 149 ± 31 mg/dL, P = 0.005). The incidence of intraoperative hyperglycemia was also greater in donors who underwent ≥3 rounds of IHIO versus those who underwent 1 or 2 rounds (38.7% versus 7.7%, odds ratio = 7.1, 95% confidence interval = 2.5-20.4, P < 0.001). Donors who did not undergo IHIO and those who underwent 1 or 2 rounds of IHIO exhibited similar maximum glucose concentrations and similar incidence rates of hyperglycemia. In conclusion, IHIO induced repeated hyperglycemic responses in living donors, and donors who underwent ≥3 rounds of IHIO were more likely to experience intraoperative hyperglycemia. These results provide additional information on the risks and benefits of IHIO in living donors.

Intraoperative hyperglycemia during liver resection: predictors and association with the extent of hepatocytes injury

Background

Patients undergoing liver resection are at risk for intraoperative hyperglycemia and acute hyperglycemia is known to induce hepatocytes injury. Thus, we aimed to evaluate whether intraoperative hyperglycemia during liver resection is associated with the extent of hepatic injury.

Methods

This 1 year retrospective observation consecutively enrolled 85 patients undergoing liver resection for hepatocellular carcinoma. Blood glucose concentrations were measured at predetermined time points including every start/end of intermittent hepatic inflow occlusion (IHIO) via arterial blood analysis. Postoperative transaminase concentrations were used as surrogate parameters indicating the extent of surgery-related acute hepatocytes injury.

Results

Thirty (35.5%) patients developed hyperglycemia (blood glucose > 180 mg/dl) during surgery. Prolonged (≥ 3 rounds) IHIO (odds ratio [OR] 7.34, P = 0.004) was determined as a risk factors for hyperglycemia as well as cirrhosis (OR 4.07, P = 0.022), lower prothrombin time (OR 0.01, P = 0.025), and greater total cholesterol level (OR 1.04, P = 0.003). Hyperglycemia was independently associated with perioperative increase in transaminase concentrations (aspartate transaminase, β 105.1, standard error 41.7, P = 0.014; alanine transaminase, β 81.6, standard error 38.1, P = 0.035). Of note, blood glucose > 160 or 140 mg/dl was not associated with postoperative transaminase concentrations.

Conclusions

Hyperglycemia during liver resection might be associated with the extent of hepatocytes injury. It would be rational to maintain blood glucose concentration < 180 mg/dl throughout the surgery in consideration of parenchymal disease, coagulation status, lipid profile, and the cumulative hepatic ischemia in patients undergoing liver resection for hepatocellular carcinoma.

Protective effect of glutamine in critical patients with acute liver injury

BACKGROUND

Glutamine (Gln) supplementation is known to decrease oxidative stress and inflammatory response, enhance resistance to infectious pathogens, shorten hospital stay, and decrease medical costs of patients. This study was undertaken to evaluate the relationship between the effect of early parenteral glutamine (Gln) supplement on acute liver injury (ALI) and heat shock protein 70 (HSP-70) expression in critical patients.

METHODS

Forty-four patients who had been admitted to the emergency intensive care unit (EICU) of Nanjing First Hospital Affiliated to Nanjing Medical University were randomly divided into a control group (n=22) and a Gln group (n=22). The patients of the two groups received enteral and parenteral nutrition. In addition, parenteral Gln 0.4 g/kg per day was given for 7 days in the Gln group. Serum HSP-70 and Gln were measured at admission and at 7 days after admission. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total bilirubin (TBiL), serum levels of HSP-70 and Gln, mechanical ventilation (MV) time, ICU stay, peripheral blood of TNF-α, IL-6, CD3, CD4 and CD4/CD8 levels were also measured in the two groups.

RESULTS

In the Gln group, the levels of serum HSP-70 and Gln were significantly higher after Gln treatment than those before the treatment (P<0.01). HSP-70 level was positively correlated with the Gln level in the Gln group after administration of parenteral Gln (P<0.01). The levels of serum ALT, AST, TBiL and TNF-α, IL-6 were lower in the Gln group than in the non-Gln group (P<0.01). MV time and ICU stay were significantly different between the two groups (P<0.05). The levels of CD3, CD4 and CD4/CD8 were significantly higher in the Gln group than in the control group after treatment (P<0.05).

CONCLUSION

Parenteral Gln significantly increases the level of serum HSP70 in critically ill patients. The enhanced expression of HSP70 is correlated with improved outcomes of Gln-treated patients with acute liver injury.

Cystathionine γ-lyase deficiency protects mice from galactosamine/lipopolysaccharide-induced acute liver failure

AIMS

Acute liver failure (ALF) is a fatal syndrome attributed to massive hepatocyte death. Hydrogen sulfide (H2S) has been reported to exert cytoprotective or cytotoxic effects. Here, we examined the role of cystathionine γ-lyase (CSE, an enzyme produces H2S) in ALF induced by D-Galactosamine (GalN) and lipopolysaccharide (LPS).

RESULTS

Wild-type (WT) mice exhibited high mortality rate, prominent liver injury, and increased plasma alanine aminotransferase levels after GalN/LPS challenge. Congenital deficiency or chemical inhibition of CSE by DL-propargylglycine attenuated GalN/LPS-induced liver injury. CSE deficiency markedly improved survival rate and attenuated GalN/LPS-induced upregulation of inflammatory cytokines and activation of caspase 3 and poly (ADP-ribose) polymerase (PARP) in the liver. CSE deficiency protected primary hepatocytes from GalN/tumor necrosis factor-α (TNF-α)-induced cell death without affecting LPS-induced TNF-α production from primary peritoneal macrophages. Beneficial effects of CSE deficiency were associated with markedly elevated homocysteine and thiosulfate levels, upregulation of NF-E2 p45-related factor 2 (Nrf2) and antioxidant proteins, activation of Akt-dependent anti-apoptotic signaling, and inhibition of GalN/LPS-induced JNK phosphorylation in the liver. Finally, administration of sodium thiosulfate (STS) attenuated GalN/LPS-induced liver injury via activation of Akt- and Nrf2-dependent signaling and inhibition of GalN/LPS-induced JNK phosphorylation in WT mice.

INNOVATION

These results suggest that inhibition of CSE or administration of STS prevents acute inflammatory liver failure by augmenting thiosulfate levels and upregulating antioxidant and anti-apoptotic defense in the liver.

CONCLUSION

Congenital deficiency or chemical inhibition of CSE increases thiosulfate levels in the liver and prevents ALF at least in part by augmentation of antioxidant and anti-apoptotic mechanisms.

Different neuroprotective responses of Ginkgolide B and bilobalide, the two Ginkgo components, in ischemic rats with hyperglycemia

Ginkgo biloba extracts show neuroprotective effects during cerebral ischemia, but with various components, the mechanisms of action remain unclear. In this study, we tested the effects of Ginkgolide B (GB) and bilobalide (BB) on normoglycemic and hyperglycemic rats subjected to transient cerebral ischemia. Rats were administered p.o. with different Ginkgo components GB (6 mg/kg) or BB (6 mg/kg) once daily for 7 days. Hyperglycemia was made by jugular vein infusion of glucose and transient middle cerebral artery occlusion/reperfusion was induced by a suture insertion technique. Results showed that both GB and BB exerted neuroprotection under normoglycemia, as determined by infarct volume and neurological deficit scores. Yet, BB showed less protective effects during hyperglycemic cerebral ischemia. Cerebral blood flow (CBF) was evaluated during occlusion and the first hour of reperfusion. BB but not GB caused acute increase in CBF after reperfusion, especially in hyperglycemia. Reactive oxygen species and malondialdehyde levels were reduced by GB in both models but BB were not effective in reactive oxygen species or malondialdehyde control in hyperglycemia ischemic rats. These results suggested that CBF plays crucial roles during early stage of reperfusion in the presence of hyperglycemia. Administration of compound that improves CBF may have little effect in hyperglycemic stroke.

Continuous monitoring of glucose levels in the hepatic vein and systemic circulation during the Pringle maneuver in beagles

Intraoperative continuous glucose monitoring revealed that liver ischemia/reperfusion causes a rapid and profound transition in glucose concentration. We hypothesized that the washout of the glucose stored in the liver leads to a rapid transition in blood glucose concentration. Six female beagles were studied. A portosystemic shunt was established, and the glucose levels in the jugular, hepatic, and portal veins were continuously monitored. All beagles were stabilized for 30 min, and, subsequently, the hepatic artery and portal vein were clamped (the Pringle maneuver). After 30 min of warm hepatic ischemia, the clamp was removed in order to initiate hepatic reperfusion. The endpoint of the experiment was 60 min after the onset of reperfusion. The glucose levels in the abovementioned veins were recorded continuously. The glucose level in the hepatic vein increased 10 min after the start of the Pringle maneuver and was significantly higher than that in the jugular vein and portal vein just before unclamping. The glucose level in the hepatic vein peaked at 2 min after unclamping and that in the portal and jugular veins started to increase after reperfusion. The glucose level in the hepatic vein was significantly higher than that in the jugular and portal veins between 9 min after clamping and 8 min after reperfusion. In conclusion, our study among beagles showed that glucose release from the hepatic vein and sinusoid leads to a rapid elevation in systemic blood glucose levels after liver ischemia/reperfusion. This knowledge might help in the development of new strategies for blood glucose management during hepatectomy.

Restoring HSP70 deficiencies improves glucose tolerance in diabetic monkeys

We evaluated heat shock protein 70 (HSP70) changes in diabetes mellitus (DM) in a nonhuman primate model. To this end, two studies were conducted in DM vervet monkeys. 1) Normal control and streptozotocin-induced DM monkeys (Stz-DM) that were differentiated into moderately or poorly controlled DM by judicious insulin administration were evaluated. Liver was collected at 4, 8, 12, 16, and 20 wk after streptozotocin, exposed to ex vivo heat shock at 42°C, and immunoblotted for heat shock factor 1 (HSF1), HSP70, and phosphorylated HSF1. 2) Spontaneous DM monkeys that were not pharmacologically induced were included in a crossover study of the HSP70-inducing drug geranylgeranylacetone (GGA). GGA at 20 mg/kg was given for 14 days with a 6-wk washout period. Glucose tolerance testing and plasma and muscle HSP70 were the primary outcome measurements. In Stz-DM, hyperglycemia reduced hepatic HSP70 in a dose-dependent fashion. HSF1 was increased in livers of monkeys with Stz-DM, but responses to ex vivo heat shock were impaired vs. normal monkeys. Activation of HSF1 appears to be important, because the phosphorylation change with heat stress was nearly perfectly correlated with HSP70 increases. Impaired HSF1 activation was also seen in Stz-DM after chronic hyperglycemia (>12 wk). In naturally occurring DM, increased circulating HSP70 resulted in significantly improved glucose tolerance and significant, positive trends in other measurements of insulin resistance. No change in muscle HSP70 content was observed. We conclude that increasing HSP70, potentially through targeting hyperglycemia-related deficits in HSF1 induction and activation in the liver, is a potent and viable strategy to improve glucose tolerance.