A Non-canonical PDK1-RSK Signal Diminishes Pro-caspase-8-Mediated Necroptosis Blockade.

Necroptosis induction in vitro often requires caspase-8 (Casp8) inhibition by zVAD because pro-Casp8 cleaves RIP1 to disintegrate the necrosome. It has been unclear how the Casp8 blockade of necroptosis is eliminated naturally. Here, we show that pro-Casp8 within the necrosome can be inactivated by phosphorylation at Thr265 (pC8T265). pC8T265 occurs in vitro in various necroptotic cells and in the cecum of TNF-treated mice. p90 RSK is the kinase of pro-Casp8. It is activated by a mechanism that does not need ERK but PDK1, which is recruited to the RIP1-RIP3-MLKL-containing necrosome. Phosphorylation of pro-Casp8 at Thr265 can substitute for zVAD to permit necroptosis in vitro. pC8T265 mimic T265E knockin mice are embryonic lethal due to unconstrained necroptosis, and the pharmaceutical inhibition of RSK-mediated pC8T265 diminishes TNF-induced cecum damage and lethality in mice by halting necroptosis. Thus, phosphorylation of pro-Casp8 at Thr265 by RSK is an intrinsic mechanism for passing the Casp8 checkpoint of necroptosis.

Spontaneous cecal perforation in a cat diagnosed with ultrasonography.

An 8-year-old cat was presented for an acute history of anorexia, marked abdominal pain, and hyperthermia. Ultrasonography showed a cecal perforation with focal steatitis and adjacent free gas bubbles, consistent with focal peritonitis. Surgery confirmed the imaging findings. An enterectomy was performed with the removal of the cecum and ileocolic valve, and anastomosis between the ileum and colon was performed. Histology revealed transmural enteritis and chronic severe pyogranulomatous peritonitis with intralesional plant fragments.

c-Abl kinase regulates neutrophil extracellular trap formation and lung injury in abdominal sepsis.

Sepsis is associated with exaggerated neutrophil responses although mechanisms remain elusive. The aim of this study was to investigate the role of c-Abelson (c-Abl) kinase in neutrophil extracellular trap (NET) formation and inflammation in septic lung injury. Abdominal sepsis was induced by cecal ligation and puncture (CLP). NETs were detected by electron microscopy in the lung and by confocal microscopy in vitro. Plasma levels of DNA-histone complexes, interleukin-6 (IL-6) and CXC chemokines were quantified. CLP-induced enhanced phosphorylation of c-Abl kinase in circulating neutrophils. Administration of the c-Abl kinase inhibitor GZD824 not only abolished activation of c-Abl kinase in neutrophils but also reduced NET formation in the lung and plasma levels of DNA-histone complexes in CLP mice. Moreover, inhibition of c-Abl kinase decreased CLP-induced lung edema and injury. Administration of GDZ824 reduced CLP-induced increases in the number of alveolar neutrophils. Inhibition of c-Abl kinase also markedly attenuated levels of CXC chemokines in the lung and plasma as well as IL-6 levels in the plasma of septic animals. Taken together, this study demonstrates that c-Abl kinase is a potent regulator of NET formation and we conclude that c-Abl kinase might be a useful target to ameliorate lung damage in abdominal sepsis.

Anthracyclines induce DNA damage response-mediated protection against severe sepsis.

Severe sepsis remains a poorly understood systemic inflammatory condition with high mortality rates and limited therapeutic options in addition to organ support measures. Here we show that the clinically approved group of anthracyclines acts therapeutically at a low dose regimen to confer robust protection against severe sepsis in mice. This salutary effect is strictly dependent on the activation of DNA damage response and autophagy pathways in the lung, as demonstrated by deletion of the ataxia telangiectasia mutated (Atm) or the autophagy-related protein 7 (Atg7) specifically in this organ. The protective effect of anthracyclines occurs irrespectively of pathogen burden, conferring disease tolerance to severe sepsis. These findings demonstrate that DNA damage responses, including the ATM and Fanconi Anemia pathways, are important modulators of immune responses and might be exploited to confer protection to inflammation-driven conditions, including severe sepsis.

Vaspin Alleviates Sepsis-Induced Cardiac Injury and Cardiac Inflammation by Inhibiting Kallikrein 7 in Mice.

Background: Vaspin is an important adipokine that is involved in cardiovascular diseases. This study is aimed at investigating whether vaspin participates in sepsis-induced cardiac injury and explored the possible mechanism. Methods: First, cecal ligation and puncture (CLP) and lipopolysaccharide (LPS) were used to establish a mouse model of sepsis, and cardiac vaspin expression was examined. In addition, after pretreatment with vaspin or phosphate-buffered saline (PBS), wild-type (WT) mice underwent CLP to establish a septic model and received sham as a control. Finally, WT mice and kallikrein 7 (KLK7-/-) mice were underwent CLP with or without vaspin pretreatment. Results: Mice that underwent CLP and were administered LPS exhibited increased vaspin expression in both the heart and serum compared with sham- or saline-treated mice. In CLP mice, pretreatment with vaspin reduced mortality and alleviated the expression of cardiac injury markers and cardiac dysfunction. In addition, vaspin reduced the cardiac levels of CD45+ cells and CD68+ cells, alleviated the cardiac inflammatory response, and reduced cardiomyocyte apoptosis. The protective effects of vaspin on CLP mice were masked by the deletion of KLK7, which was demonstrated to be a downstream signal of vaspin. Conclusions: Vaspin alleviates cardiac inflammation and plays a protective role in sepsis-induced cardiac injury by reducing KLK7 expression.

Metformin attenuates sepsis-induced neuronal injury and cognitive impairment.

BACKGROUND: Sepsis is considered to be a high-risk factor for cognitive impairment in the brain. The purpose of our study is to explore whether sepsis causes cognitive impairment and try to evaluate the underlying mechanisms and intervention measures. METHODS: Here, we used cecum ligation and puncture (CLP) to simulate sepsis. Open field, Novel Objective Recognition, and Morris Water Maze Test were used to detect cognitive function, long-term potentiation was used to assess of synaptic plasticity, and molecular biological technics were used to assess synaptic proteins, ELISA kits were used to detect inflammatory factors. Metformin was injected into the lateral ventricle of SD rats, and we evaluated whether metformin alleviated CLP-mediated cognitive impairment using behavioral, electrophysiological and molecular biological technology experiments. RESULTS: Here we report hippocampal-dependent cognitive deficits and synaptic dysfunction induced by the CLP, accompanied by a significant increase in inflammatory factors. At the same time, metformin was able to improve cognitive impairment induced by CLP in adult male rats. CONCLUSION: These findings highlight a novel pathogenic mechanism of sepsis-related cognitive impairment through activation of inflammatory factors, and these are blocked by metformin to attenuate sepsis-induced neuronal injury and cognitive impairment.

Transcriptomic Analysis Reveals Differential Expression of Genes between Lung Capillary and Post Capillary Venules in Abdominal Sepsis.

Lung endothelial cell dysfunction plays a central role in septic-induced lung injury. We hypothesized that endothelial cell subsets, capillary endothelial cells (capEC) and post capillary venules (PCV), might play different roles in regulating important pathophysiology in sepsis. In order to reveal global transcriptomic changes in endothelial cell subsets during sepsis, we induced sepsis in C57BL/6 mice by cecal ligation and puncture (CLP). We confirmed that CLP induced systemic and lung inflammation in our model. Endothelial cells (ECs) from lung capillary and PCV were isolated by cell sorting and transcriptomic changes were analyzed by bioinformatic tools. Our analysis revealed that lung capEC are transcriptionally different than PCV. Comparison of top differentially expressed genes (DEGs) of capEC and PCV revealed that capEC responses are different than PCV during sepsis. It was found that capEC are more enriched with genes related to regulation of coagulation, vascular permeability, wound healing and lipid metabolic processes after sepsis. In contrast, PCV are more enriched with genes related to chemotaxis, cell-cell adhesion by integrins, chemokine biosynthesis, regulation of actin filament process and neutrophil homeostasis after sepsis. In addition, we predicted some transcription factor targets that regulate a significant number of DEGs in sepsis. We proposed that targeting certain DEGs or transcriptional factors would be useful in protecting against sepsis-induced lung damage.

Trained Innate Immunity by Repeated Low-Dose Lipopolysaccharide Injections Displays Long-Term Neuroprotective Effects.

Disrupted immune response is an important feature of many neurodegenerative conditions, including sepsis-associated cognitive impairment. Accumulating evidence has demonstrated that immune memory occurs in microglia, which has a significant impact on pathological hallmarks of neurological diseases. However, it remains unclear whether immune memory can cause subsequent alterations in the brain immune response and affect neurobehavioral outcomes in sepsis survivors. In the present study, mice received daily intraperitoneal injection of low-dose lipopolysaccharide (LPS, 0.1 mg/kg) for three consecutive days to induce immune memory (immune tolerance) and then were subjected to sham operation or cecal ligation and puncture (CLP) 9 months later, followed by a battery of neurobehavioral and biochemical studies. Here, we showed that repeated low-dose LPS injection-induced immune memory protected mice from sepsis-induced cognitive and affective impairments, which were accompanied by significantly decreased brain proinflammatory cytokines and immune response. In conclusion, our study suggests that modulation of brain immune responses by repeated LPS injections confers neuroprotective effects by preventing overactivated immune response in response to subsequent septic insult.

The novel mechanism of valproate to prevent peritoneal adhesion formation.

PURPOSE: A novel pharmacological mechanism of valproate was analyzed using a hamster model of adhesion. METHODS: Valproate or placebo was administered just after cecal injury and adhesion severity scores and histological were analyzed. RESULTS: The adhesion severity scores in the placebo- and valproate-treated groups were 2.67 ± 0.42 and 1.0 ± 0.37, respectively, with a significant difference between the groups. A significant increase in mast cell numbers was observed in the placebo-treated group vs. the sham-operated group; however, the mast cell number in the adhesive lesion was significantly lower in the valproate-treated group than in the placebo-treated group. The number of cells positive for chymase, an enzyme in mast cells, in the adhesive lesion was significantly higher in the placebo-treated group, but its increase was attenuated significantly by treatment with valproate. The myeloperoxidase gene expression level in the cecum was significantly higher in the placebo-treated group than in the sham-operated group, but there was no significant difference in the myeloperoxidase gene expression level between the sham-operated and valproate-treated groups in. In an in vitro experiment, valproate inhibited purified human and hamster chymases dose-dependently. CONCLUSION: The chymase inhibitory effect of valproate may contribute to prevent adhesion formation after abdominal injury.

Cardioprotective Effect of Tangeretin by Inhibiting PTEN/AKT/mTOR Axis in Experimental Sepsis-Induced Myocardial Dysfunction.

Sepsis aggregates undesirable immune response causing depression of ventricular myocardium and diastolic dysfunction. This present study examined the effect of a plant-derived flavone tangeretin (TG) on autophagy and reduction in myocardial dysfunction. The sepsis was induced by cecum ligation and puncture (CLP) in male Sprague-Dawley rats. Abnormal changes were seen in the heart after the sepsis induction. These abnormalities were analyzed based on the cardiac markers, namely Cardiac myosin light chain-1 (cMLC1) and Cardiac troponin I (cTnl), echocardiography, and plasma parameters, like Lactate dehydrogenase (LDH) and Creatinine kinase (CK). Microanatomy of the heart was studied using hematoxylin and eosin stained histopathological samples of cardiac tissue. Western blot technique was used to detect the nature and extent of protein with the amount of a specific RNA (gene expression) in the cardiac homogenate. Oxidative damage was analyzed using redox marker, reduced glutathione. This study successfully showed that TG attenuated sepsis-induced myocardial dysfunction by inhibiting myocardial autophagy via silencing the Phosphatase and tensin homolog (PTEN) expression and acting on the AKT/mTOR pathway. The present findings supported that TG is a novel cardioprotective therapeutic target for sepsis induced myocardial dysfunction.

Ulinastatin attenuates liver injury and inflammation in a cecal ligation and puncture induced sepsis mouse model.

Sepsis is a syndrome of life-threatening multiorgan dysfunction caused by host response dysregulation to infection. Ulinastatin (UTI), a serine protease inhibitor, possesses anti-inflammatory properties and has been suggested to modulate lipopolysaccharide-induced sepsis. However, little is known about the mechanism underlying its effects on sepsis. In the current study, we investigated the protective effect of UTI on liver injury in a cecal ligation and puncture (CLP)-induced sepsis of C57BL/6 mouse model and explored the possible mechanisms. Mice underwent CLP as sepsis models and were randomized into five groups including the sham group, UTI group, CLP group, UTI-L group, and UTI-H group. UTI was intraperitoneally administered at doses of UTI 1500 U/100 g (UTI-L group) or 3000 U/100 g (UTI-H group), before CLP. The mice were killed, and immunohistochemical changes, cytokine levels, and antioxidant enzyme activities were detected. Our results showed that UTI ameliorated CLP-mediated increases in serum aspartate aminotransferase and alanine aminotransferase activities, histological activity index, degenerative region ratio, and infiltrated inflammatory cell numbers. Moreover, UTI also decreased nitrotyrosine and 4-hydroxynonenal, activated caspase-3, and activated poly (ADP-ribose) polymerase (PARP) levels and inhibited the mitogen-activated protein kinase pathway activation in liver tissues. Our results indicated that UTI could inhibit CLP-induced liver injury by suppressing inflammation and oxidation. Our results indicated that UTI may serve as a potential therapeutic agent for sepsis.

Klotho deficiency aggravates sepsis-related multiple organ dysfunction.

Sepsis-induced organ failure is characterized by a massive inflammatory response and oxidative stress. Acute kidney injury (AKI) occurs in approximately half of patients in septic shock, and the mortality associated with sepsis-induced AKI is unacceptably high. Klotho is a protein expressed by renal cells and has anti-senescence properties. Klotho has also been shown to protect the kidneys in ischemia-reperfusion injury and to have antioxidant properties. To analyze the role of Klotho in sepsis-related organ dysfunction and AKI, we used a cecal ligation and puncture (CLP) model of sepsis in heterozygous Klotho-haploinsufficient mice and their wild-type littermates (CLP- Kl/+ and CLP-WT mice, respectively). In comparison with the CLP-WT mice, CLP- Kl/+ mice showed lower survival, impaired renal function, impaired hepatic function, greater oxidative stress, upregulation of inflammatory pathways (at the systemic and kidney tissue levels), and increased NF-κB activation. It is noteworthy that CLP- Kl/+ mice also showed lower heart-rate variability, less sympathetic activity, impaired baroreflex sensitivity to sodium nitroprusside, and a blunted blood pressure response to phenylephrine. We also demonstrated that sepsis creates a state of acute Klotho deficiency. Given that low Klotho expression exacerbates sepsis and multiple organ dysfunction, Klotho might play a protective role in sepsis, especially in elderly individuals in whom Klotho expression is naturally reduced.

Early hyperbaric oxygen therapy improves survival in a model of severe sepsis.

Sepsis is a major clinical challenge, with therapy limited to supportive interventions. Therefore, the search for novel remedial approaches is of great importance. We addressed whether hyperbaric oxygen therapy (HBOT) could improve the outcome of sepsis using an acute experimental mouse model. Sepsis was induced in male CD-1 mice by cecal ligation and puncture (CLP) tailored to result in 80-90% mortality within 72 h of the insult. After CLP, mice were randomized into two groups receiving HBOT or not at different times after the initial insult or subjected to multiple HBOT treatments. HBOT conditions were 98% oxygen pressurized to 2.4 atmospheres for 1 h. HBOT within 1 h after CLP resulted in 52% survival in comparison with mice that did not receive the treatment (13% survival). Multiple HBOT at 1 and 6 h or 1, 6, and 21 h displayed an increase in survival of >50%, but they were not significantly different from a single treatment after 1 h of CLP. Treatments at 6 or 21 h after CLP, excluding the 1 h of treatment, did not show any protective effect. Early HBO treatment did not modify bacterial counts after CLP, but it was associated with decreased expression of TNF-α, IL-6, and IL-10 expression in the liver within 3 h after CLP. The decrease of cytokine expression was reproduced in cultured macrophages after exposure to HBOT. Early HBOT could be of benefit in the treatment of sepsis, and the protective mechanism may be related to a reduction in the systemic inflammatory response.

A minimally invasive treatment of an asymptomatic case of mesh erosion into the caecum after total extraperitoneal inguinal hernia repair.

BACKGROUND: Mesh migration and erosion into adjacent viscera is a rare complication after laparoscopic inguinal hernia repair. We present a minimally invasive treatment of an asymptomatic case of mesh erosion into the caecum after total extraperitoneal inguinal hernia repair, including an overview of the relevant recent literature. METHODS: A male patient underwent a laparoscopic inguinal hernia repair at the age of 42. Two years after this procedure, a screening colonoscopy revealed erosion of the mesh into the caecum. A laparoscopy was performed with partial resection of the mesh and minimal resection of the involved colon. Results of a systematic review of English PubMed articles on mesh migration and erosion after inguinal hernia repair is presented. RESULTS: We report a first-time minimally invasive treatment of mesh erosion into the colon. A laparoscopic approach is feasible and provides an excellent exposure. Partial removal of the mesh is suggested in uncomplicated cases to avoid complications associated with complete mesh removal.

Tephrosin attenuates sepsis induced acute lung injury in rats by impeding expression of ICAM-1 and MIP-2.

Acute lung injury (ALI), a devastating form of respiratory infections, is characterized by increased edema, release of cytokines, weakened arterial oxygenation and infiltration of neutrophils and lymphocytes. The objective of the research envisaged was to reveal protective effects of tephrosin (TP) in ALI. In the present investigation, sepsis was triggered in rats by cecal ligation and puncture (CLP) method, and TP was administered intraperitonially. Five groups - Group A (control), Group B (Sham group) Group C (infected and untreated), and Group D and E (infected and treated with 25 and 50 mg/kg TP respectively) - of ten rats each, were used for the investigation. Evaluation parameters included measurement of arterial oxygenation, lung water content, protein determination, cytokine determination, neutrophil and lymphocyte count in the bronchoalveolar lavage fluid (BALF). As indicated by histopathological examination, the lung injury score was maximum in group C, but indicated reduction in group D and E. Intracellular adhesion molecule (ICAM)-1 and macrophage inflammatory protein-2 (MIP-2) are known to be important mediators responsible for ALI. Reduction in the ICAM-1 and MIP-2 expression was found to reduce after treatment with TP. In comparison to group D, group E reflected higher magnitude of ICAM-1 and MIP-2 suppression due to administration of higher TP dose. Compared to Group A and B, Group E indicated slightly higher expression of ICAM-1 and MIP-2. The research envisaged thus supports that TP attenuates ICAM-1 and MIP-2 expression in sepsis induced ALI rat model.

Lactate as a Potential Biomarker of Sepsis in a Rat Cecal Ligation and Puncture Model.

We attempted to investigate whether blood lactate is a useful biomarker for sepsis in a rat cecal ligation and puncture (CLP) model. Male Sprague-Dawley rats underwent approximately 75% cecum ligation and two punctures to induce high-grade sepsis. A lactate of 1.64 mmol/L (Youden score of 0.722) was selected as the best cutoff value to predict the onset of sepsis after CLP exposure; 46 of 50 rats who survived 24 hours after the CLP were divided into the L group (lactate < 1.64 mmol/L) and M group (lactate ≥ 1.64 mmol/L). In the M group, the animals had significantly higher murine sepsis scores and none survived 5 days post-CLP, and the rate of validated septic animals, serum procalcitonin, high mobility group box 1, blood urea nitrogen, alanine transaminase, cardiac troponin I, and the wet-to-dry weight ratio were significantly higher compared to the L group. Worsen PaO2/FiO2, microcirculations, and mean arterial pressure were observed in the M group. More severe damage in major organs was confirmed by histopathological scores in the M group compared with the L group. In conclusion, lactate ≥ 1.64 mmol/L might serve as a potential biomarker to identify the onset of sepsis in a rat CLP model.

Identifying Therapeutic Targets for Sepsis Research: A Characterization Study of the Inflammatory Players in the Cecal Ligation and Puncture Model.

During sepsis, disturbed gastrointestinal motility and increased mucosal permeability can aggravate sepsis due to the increased risk of bacterial translocation. To help identify new therapeutic targets, there is a need for animal models that mimic the immunological changes in the gastrointestinal tract as observed during human sepsis. We therefore characterized in detail the gastrointestinal neuroimmune environment in the cecal ligation and puncture (CLP) model, which is the gold standard animal model of microbial sepsis. Mice were sacrificed at day 2 and day 7, during which gastrointestinal motility was assessed and cytokines were measured in the serum and the colon. In the spleen, lymph nodes, ileum, and colon, subsets of leukocyte populations were identified by flow cytometry. Septic animals displayed an impaired gastrointestinal motility at day 2 and day 7. Two days post-CLP, increased serum and colonic levels of proinflammatory cytokines were measured. Flow cytometry revealed an influx of neutrophils in the colon and ileum, increased numbers of macrophages in the spleen and mesenteric lymph nodes, and an enhanced number of mast cells in all tissues. At day 7 post-CLP, lymphocyte depletion was observed in all tissues coinciding with increased IL-10 and TGF-ß levels, as well as increased colonic levels of IL-17A and IFN-γ. Thus, CLP-induced sepsis in mice results in simultaneous activation of pro- and anti-inflammatory players at day 2 and day 7 in different tissues, mimicking human sepsis.

Cecal perforation: A rare complication of a ventriculoperitoneal shunt.

Hydrocephalus can be the result of an infection, obstruction, impaired reabsorption of cerebrospinal fluid (CSF), or an abnormal increase in CSF. Ventriculoperitoneal (VP) shunting is the gold standard treatment for hydrocephalus despite its high rate of complications, including catheter obstruction and infection. Spontaneous cecal perforation by a VP shunt is extremely rare. Headache or subtle change in personality may indicate a VP shunt infection. Early recognition of the infection is critical for optimal patient outcomes.

Protective Effects of Human and Mouse Soluble Scavenger-Like CD6 Lymphocyte Receptor in a Lethal Model of Polymicrobial Sepsis.

Sepsis still constitutes an unmet clinical need, which could benefit from novel adjunctive strategies to conventional antibiotic therapy. The soluble form of the scavenger-like human CD6 lymphocyte receptor (shCD6) binds to key pathogenic components from Gram-positive and -negative bacteria and shows time- and dose-dependent efficacy in mouse models of monobacterial sepsis. The objective of the present work was to demonstrate the effectiveness of infusing mouse and human sCD6 by different systemic routes, either alone or as adjunctive therapy to gold standard antibiotics, in a lethal model of polymicrobial sepsis. To this end, C57BL/6 mice undergoing high-grade septic shock induced by cecal ligation and puncture (CLP; ≥90% lethality) were infused via the intraperitoneal (i.p.) or intravenous (i.v.) route with shCD6 at different doses and time points, either alone or in combination with imipenem/cilastatin (I/C) at a dose of 33 mg/kg of body weight every 8 h. Significantly reduced mortality and proinflammatory cytokine levels were observed by i.p. infusion of a single shCD6 dose (1.25 mg/kg) 1 h pre- or post-CLP. When using the i.v. route, mice survival was significantly extended by starting shCD6 infusion at later time points post-CLP (up to 6 h after CLP). Significant adjunctive effects on mouse survival were observed by i.p. or i.v. infusion of shCD6 in combination with i.p. I/C post-CLP. Similar results were obtained in mice expressing high sustained levels (5 to 10 µg/ml) of mouse sCD6 in serum by means of transduction with hepatotropic adeno-associated virus (AAV). Taken together, the data support the conserved antibacterial effects of human and mouse sCD6 and their use as adjunctive therapy in experimental models of complex and severe polymicrobial sepsis.