Intraperitoneal insufflation of carbon dioxide rescues intestinal damage in an experimental murine model of colitis.

OBJECTIVES: Necrotizing enterocolitis (NEC) is a severe neonatal surgical condition, associated with a prolonged pro-inflammatory state, leading to high mortality and morbidity rates. Carbon dioxide (CO2 ) insufflation during laparoscopy may have an anti-inflammatory effect. We aimed to evaluate the effects of CO2 -insufflation on experimental colitis. METHODS: Acute colitis was induced in 6-week-old Balb/c mice by the administration of 2%-dextran sulfate-sodium (DSS) during 7 days (n = 45). On Day 4, two groups received intraperitoneal insufflation (duration: 30 mn, pressure: 5 mmHg) of CO2 ("DSS+CO2 ") or air ("DSS+air"). A group received no insufflation ("DSS"). Groups were compared for clinical severity using the disease activity index (DAI-body weight loss, stool consistency, and bleeding), histological severity (histopathological activity index, colon length, and ulcerations), colonic mucosecretion, and inflammation. RESULTS: DAI was significantly decreased in DSS+CO2 group, compared to DSS (p < 0.0001) or DSS+air (p < 0.0001) groups. Colon length was increased in DSS+CO2 treated mice compared to DSS (p = 0.0002). The histopathological activity index was lower in DSS+CO2 (vs. DSS, p = 0.0059/vs. DSS+air, p = 0.0389), with decreased ulcerations (3.77 vs. 10.7, p = 0.0306), and persistent mucosecretion with increased mucin-secreting cells. CONCLUSIONS: CO2 -insufflation attenuates DSS-induced colitis and improves both clinical and histological scores. Laparoscopy with CO2 insufflation represents a therapeutic anti-inflammatory strategy for NEC.

Targeting the endo-lysosomal autophagy pathway to treat inflammatory bowel diseases.

Inflammatory bowel disease (IBD) is a serious public health problem in Western society with a continuing increase in incidence worldwide. Safe, targeted medicines for IBD are not yet available. Autophagy, a vital process implicated in normal cell homeostasis, provides a potential point of entry for the treatment of IBDs, as several autophagy-related genes are associated with IBD risk. We conducted a series of experiments in three distinct mouse models of colitis to test the effectiveness of therapeutic P140, a phosphopeptide that corrects autophagy dysfunctions in other autoimmune and inflammatory diseases. Colitis was experimentally induced in mice by administering dextran sodium sulfate and 2,4,6 trinitrobenzene sulfonic acid. Transgenic mice lacking both il-10 and iRhom2 - involved in tumor necrosis factor α secretion - were also used. In the three models investigated, P140 treatment attenuated the clinical and histological severity of colitis. Post-treatment, altered expression of several macroautophagy and chaperone-mediated autophagy markers, and of pro-inflammatory mediators was corrected. Our results demonstrate that therapeutic intervention with an autophagy modulator improves colitis in animal models. These findings highlight the potential of therapeutic peptide P140 for use in the treatment of IBD.

A Preclinical Validation of Iron Oxide Nanoparticles for Treatment of Perianal Fistulizing Crohn's Disease.

Fistulizing anoperineal lesions are severe complications of Crohn's disease (CD) that affect quality of life with a long-term risk of anal sphincter destruction, incontinence, permanent stoma, and anal cancer. Despite several surgical procedures, they relapse in about two-thirds of patients, mandating innovative treatments. Ultrasmall particles of iron oxide (USPIO) have been described to achieve in vivo rapid healing of deep wounds in the skin and liver of rats thanks to their nanobridging capability that could be adapted to fistula treatment. Our main purpose was to highlight preclinical data with USPIO for the treatment of perianal fistulizing CD. Twenty male Sprague Dawley rats with severe 2,4,6-trinitrobenzenesulfonic acid solution (TNBS)-induced proctitis were operated to generate two perianal fistulas per rat. At day 35, two inflammatory fistulas were obtained per rat and perineal magnetic resonance imaging (MRI) was performed. After a baseline MRI, a fistula tract was randomly drawn and topically treated either with saline or with USPIO for 1 min (n = 17 for each). The rats underwent a perineal MRI on postoperative days (POD) 1, 4, and 7 and were sacrificed for pathological examination. The primary outcome was the filling or closure of the fistula tract, including the external or internal openings. USPIO treatment allowed the closure and/or filling of all the treated fistulas from its application until POD 7 in comparison with the control fistulas (23%). The treatment with USPIO was safe, permanently closed the fistula along its entire length, including internal and external orifices, and paved new avenues for the treatment of perianal fistulizing Crohn's disease.

The cecal appendix is correlated with greater maximal longevity in mammals.

The cecal appendix had been considered as a useless vestige since Darwin's work, but recent research questioned this idea demonstrating that the cecal appendix appeared among the mammals at least 80 million years ago and has made multiple and independent appearances without any obvious correlation with diet, social life, ecology, or size of the cecum. However, functions and probable selective advantage conferred by this anatomical structure still remain enigmatic. We found, through analyses of data on 258 mammalian species, that cecal appendix presence is correlated with increased maximal observed longevity. This is the first demonstration of a correlation between cecal appendix presence and life history. Interestingly, the classical evolutionary theory of aging that predicts an increased longevity when the extrinsic mortality is reduced has been questioned several times, but recent comparative studies asserted its validity in the taxa, which experience age-dependent and density-dependent mortality, as in mammals. Thus, the cecal appendix may contribute to the increase in longevity through a reduction of extrinsic mortality. A lower risk of fatal infectious diarrhea is one of the most plausible hypotheses that could explain it. However, several hypotheses coexist about the possible functions of the cecal appendix, and our results provide new insights about this much-disputed question. In addition, we show that the cecal appendix arose at least 16 times and was lost only once during the evolutionary history of the considered mammals, an asymmetry that supports the existence of a positive selective of this structure.

A Turing mechanism in order to explain the patchy nature of Crohn's disease.

Crohn's disease is an inflammatory bowel disease (IBD) that is not well understood. In particular, unlike other IBDs, the inflamed parts of the intestine compromise deep layers of the tissue and are not continuous but separated and distributed through the whole gastrointestinal tract, displaying a patchy inflammatory pattern. In the present paper, we introduce a toy-model which might explain the appearance of such patterns. We consider a reaction-diffusion system involving bacteria and phagocyte and prove that, under certain conditions, this system might reproduce an activator-inhibitor dynamic leading to the occurrence of Turing-type instabilities. In other words, we prove the existence of stable stationary solutions that are spatially periodic and do not vanish in time. We also propose a set of parameters for which the system exhibits such phenomena and compare it with realistic parameters found in the literature. This is the first time, as far as we know, that a Turing pattern is investigated in inflammatory models.

Colonic MicroRNA Profiles, Identified by a Deep Learning Algorithm, That Predict Responses to Therapy of Patients With Acute Severe Ulcerative Colitis.

BACKGROUND & AIMS: Acute severe ulcerative colitis (ASUC) is a life-threatening condition managed with intravenous steroids followed by infliximab, cyclosporine, or colectomy (for patients with steroid resistance). There are no biomarkers to identify patients most likely to respond to therapy; ineffective medical treatment can delay colectomy and increase morbidity and mortality. We aimed to identify biomarkers of response to medical therapy for patients with ASUC. METHODS: We performed a retrospective analysis of 47 patients with ASUC, well characterized for their responses to steroids, cyclosporine, or infliximab, therapy at 2 centers in France. Fixed colonic biopsies, collected before or within the first 3 days of treatment, were used for microarray analysis of microRNA expression profiles. Deep neural network-based classifiers were used to derive candidate biomarkers for discriminating responders from non-responders to each treatment and to predict which patients would require colectomy. Levels of identified microRNAs were then measured by quantitative PCR analysis in a validation cohort of 29 independent patients-the effectiveness of the classification algorithm was tested on this cohort. RESULTS: A deep neural network-based classifier identified 9 microRNAs plus 5 clinical factors, routinely recorded at time of hospital admission, that associated with responses of patients to treatment. This panel discriminated responders to steroids from non-responders with 93% accuracy (area under the curve, 0.91). We identified 3 algorithms, based on microRNA levels, that identified responders to infliximab vs non-responders (84% accuracy, AUC = 0.82) and responders to cyclosporine vs non-responders (80% accuracy, AUC = 0.79). CONCLUSION: We developed an algorithm that identifies patients with ASUC who respond vs do not respond to first- and second-line treatments, based on microRNA expression profiles in colon tissues.

Quantitative MRI in murine radiation-induced rectocolitis: comparison with histopathological inflammation score.

Murine radiation-induced rectocolitis is considered to be a relevant animal model of gastrointestinal inflammation. The purpose of our study was to compare quantitative MRI and histopathological features in this gastrointestinal inflammation model. Radiation rectocolitis was induced by localized single-dose radiation (27 Gy) in Sprague-Dawley rats. T2 -weighted, T1 -weighted and diffusion-weighted MRI was performed at 7 T in 16 rats between 2 and 4 weeks after irradiation and in 10 control rats. Rats were sacrificed and the histopathological inflammation score of the colorectal samples was assessed. The irradiated rats showed significant increase in colorectal wall thickness (2.1 ± 0.3 mm versus 0.8 ± 0.3 mm in control rats, P < 0.0001), normalized T2 signal intensity (4 ± 0.8 versus 2 ± 0.4 AU, P < 0.0001), normalized T1 signal intensity (1.4 ± 0.1 versus 1.1 ± 0.2 AU, P = 0.0009) and apparent and pure diffusion coefficients (ADC and D) (2.06 × 10-3 ± 0.34 versus 1.51 × 10-3 ± 0.23 mm2 /s, P = 0.0004, and 1.97 × 10-3 ± 0.43 mm2 /s versus 1.48 × 10-3 ± 0.29 mm2 /s, P = 0.008, respectively). Colorectal wall thickness (r = 0.84, P < 0.0001), normalized T2 signal intensity (r = 0.85, P < 0.0001) and ADC (r = 0.80, P < 0.0001) were strongly correlated with the histopathological inflammation score, whereas normalized T1 signal intensity and D were moderately correlated (r = 0.64, P = 0.0006, and r = 0.65, P = 0.0003, respectively). High-field MRI features of single-dose radiation-induced rectocolitis in rats differ significantly from those of control rats. Quantitative MRI characteristics, especially wall thickness, normalized T2 signal intensity, ADC and D, are potential markers of the histopathological inflammation score.

Modulation of Protein Disulfide Isomerase Functions by Localization: The Example of the Anterior Gradient Family.

Significance: Oxidative folding within the endoplasmic reticulum (ER) introduces disulfide bonds into nascent polypeptides, ensuring proteins' stability and proper functioning. Consequently, this process is critical for maintaining proteome integrity and overall health. The productive folding of thousands of secretory proteins requires stringent quality control measures, such as the unfolded protein response (UPR) and ER-Associated Degradation (ERAD), which contribute significantly to maintaining ER homeostasis. ER-localized protein disulfide isomerases (PDIs) play an essential role in each of these processes, thereby contributing to various aspects of ER homeostasis, including maintaining redox balance, proper protein folding, and signaling from the ER to the nucleus. Recent Advances: Over the years, there have been increasing reports of the (re)localization of PDI family members and other ER-localized proteins to various compartments. A prime example is the anterior gradient (AGR) family of PDI proteins, which have been reported to relocate to the cytosol or the extracellular environment, acquiring gain of functions that intersect with various cellular signaling pathways. Critical Issues: Here, we summarize the functions of PDIs and their gain or loss of functions in non-ER locations. We will focus on the activity, localization, and function of the AGR proteins: AGR1, AGR2, and AGR3. Future Directions: Targeting PDIs in general and AGRs in particular is a promising strategy in different human diseases. Thus, there is a need for innovative strategies and tools aimed at targeting PDIs; those strategies should integrate the specific localization and newly acquired functions of these PDIs rather than solely focusing on their canonical roles.

Abnormal activation of autophagy-induced crinophagy in Paneth cells from patients with Crohn's disease.

Autophagy-related 16 like-1 (ATG16L-1), immunity-related GTPase-M (IRGM), and nucleotide-binding oligomerization domain-containing 2 (NOD2) regulate autophagy, and variants in these genes have been associated with predisposition to Crohn's disease (CD). However, little is known about the role of autophagy in CD. Intestinal biopsies from untreated pediatric patients with CD, celiac disease, or ulcerative colitis were analyzed by immunohistochemistry and electron microscopy. We observed that autophagy was specifically activated in Paneth cells from patients with CD, independently of mucosal inflammation or disease-associated variants of ATG16L1 or IRGM. In these cells, activation of autophagy was associated with a significant decrease in number of secretory granules and features of crinophagy. These observations might account for the disorganization of secretory granules previously reported in Paneth cells from patients with CD.

Correlation between the presence of a cecal appendix and reduced diarrhea severity in primates: new insights into the presumed function of the appendix.

Increased severity or recurrence risk of some specific infectious diarrhea, such a salmonellosis or Clostridium difficile colitis, have been reported after an appendectomy in human patients. While several other mammals also possess an appendix, the suspected protective function against diarrhea conferred by this structure is known only in humans. From a retrospective collection of veterinary records of 1251 primates attributed to 45 species, including 13 species with an appendix and 32 without, we identified 2855 episodes of diarrhea, 13% of which were classified as severe diarrhea requiring a therapeutic medication or associated with a fatal issue. We identified a lower risk of severe diarrhea among primate species with an appendix, especially in the early part of life when the risk of diarrhea is maximal. Moreover, we observed a delayed onset of diarrhea and of severe diarrhea in species possessing an appendix. Interestingly, none of the primates with an appendix were diagnosed, treated or died of an acute appendicitis during the 20 years of veterinarian follow-up. These results clarify the function of the appendix among primates, as protection against diarrhea. This supports its presumed function in humans and is congruent with the existence of a selective advantage conferred by this structure.

The Appendix Orchestrates T-Cell Mediated Immunosurveillance in Colitis-Associated Cancer.

BACKGROUND & AIMS: Although appendectomy may reduce colorectal inflammation in patients with ulcerative colitis (UC), this surgical procedure has been suggested to be associated with an increased risk of colitis-associated cancer (CAC). Our aim was to explore the mechanism underlying the appendectomy-associated increased risk of CAC. METHODS: Five-week-old male BALB/c mice underwent appendectomy, appendicitis induction, or sham laparotomy. They were then exposed to azoxymethane/dextran sodium sulfate (AOM/DSS) to induce CAC. Mice were killed 12 weeks later, and colons were taken for pathological analysis and immunohistochemistry (CD3 and CD8 staining). Human colonic tumors from 21 patients with UC who underwent surgical resection for CAC were immunophenotyped and stratified according to appendectomy status. RESULTS: Whereas appendectomy significantly reduced colitis severity and increased CAC number, appendicitis induction without appendectomy led to opposite results. Intratumor CD3+ and CD8+ T-cell densities were lower after appendectomy and higher after appendicitis induction compared with the sham laparotomy group. Blocking lymphocyte trafficking to the colon with the anti-α4ß7 integrin antibody or a sphingosine-1-phosphate receptor agonist suppressed the inducing effect of the appendectomy on tumors' number and on CD3+/CD8+ intratumoral density. CD8+ or CD3+ T cells isolated from inflammatory neo-appendix and intravenously injected into AOM/DSS-treated recipient mice increased CD3+/CD8+ T-cell tumor infiltration and decreased tumor number. In UC patients with a history of appendectomy, intratumor CD3+ and CD8+ T-cell densities were decreased compared with UC patients without history of appendectomy. CONCLUSIONS: In UC, appendectomy could suppress a major site of T-cell priming, resulting in a less efficient CAC immunosurveillance.

Altered endoplasmic reticulum stress affects translation in inactive colon tissue from patients with ulcerative colitis.

BACKGROUND & AIMS: Ulcerative colitis (UC) is a chronic inflammatory disorder that affects the colonic epithelium. Epidemiology studies indicate an environmental component is involved in pathogenesis, although the primary changes in the digestive epithelium that cause an uncontrolled inflammatory response are not known. Animal studies have shown that altered endoplasmic reticulum (ER) stress response initiates intestinal inflammation in epithelial tissues, but abnormalities associated with ER stress have not been identified in patients with UC. METHODS: Using immunoblotting, real-time polymerase chain reaction, immunohistochemistry, and immunofluorescence analyses, we assessed ER stress signaling in uninflammed colonic mucosa from patients with UC and controls. Genome-wide microarray analysis of actively translated polysome-bound messenger RNA was performed using samples of unaffected mucosa from patients with UC, and data were compared with those from controls. RESULTS: Inositol-requiring kinase and activating transcription factor signaling pathways were activated in inactive colonic epithelium from patients with UC; these mediate proinflammatory and regenerative responses. Blocking phosphorylation of the translation initiation factor 2 (eIF2α), which mediates the integrated stress response, deregulated initiation of translation and reduced the numbers of stress granules in colonic epithelial cells from patients with UC. Genome-wide microarray analysis of actively translated, polysome-bound messenger RNA from patients revealed changes in protein translation that altered colonic epithelial barrier function (levels of detoxification and antioxidant enzymes and proteins that regulate the cell cycle, cell-cell adhesion, and secretion), compared with controls. CONCLUSIONS: Colonic mucosa samples from patients with UC have defects in the eIF2α pathway that controls protein translation and the cell stress response. This pathway might be investigated to identify new therapeutic targets for patients with UC.

Anterior gradient proteins in gastrointestinal cancers: from cell biology to pathophysiology.

Most of the organs of the digestive tract comprise secretory epithelia that require specialized molecular machines to achieve their functions. As such anterior gradient (AGR) proteins, which comprise AGR1, AGR2, and AGR3, belong to the protein disulfide isomerase family, and are involved in secretory and transmembrane protein biogenesis in the endoplasmic reticulum. They are generally expressed in epithelial cells with high levels in most of the digestive tract epithelia. To date, the vast majority of the reports concern AGR2, which has been shown to exhibit various subcellular localizations and exert pro-oncogenic functions. AGR2 overexpression has recently been associated with a poor prognosis in digestive cancers. AGR2 is also involved in epithelial homeostasis. Its deletion in mice results in severe diffuse gut inflammation, whereas in inflammatory bowel diseases, the secretion of AGR2 in the extracellular milieu participates in the reshaping of the cellular microenvironment. AGR2 thus plays a key role in inflammation and oncogenesis and may represent a therapeutic target of interest. In this review, we summarize the already known roles and mechanisms of action of the AGR family proteins in digestive diseases, their expression in the healthy digestive tract, and in digestive oncology. At last, we discuss the potential diagnostic and therapeutic implications underlying the biology of AGR proteins.

The Heterochromatin protein 1 is a regulator in RNA splicing precision deficient in ulcerative colitis.

Defects in RNA splicing have been linked to human disorders, but remain poorly explored in inflammatory bowel disease (IBD). Here, we report that expression of the chromatin and alternative splicing regulator HP1γ is reduced in ulcerative colitis (UC). Accordingly, HP1γ gene inactivation in the mouse gut epithelium triggers IBD-like traits, including inflammation and dysbiosis. In parallel, we find that its loss of function broadly increases splicing noise, favoring the usage of cryptic splice sites at numerous genes with functions in gut biology. This results in the production of progerin, a toxic splice variant of prelamin A mRNA, responsible for the Hutchinson-Gilford Progeria Syndrome of premature aging. Splicing noise is also extensively detected in UC patients in association with inflammation, with progerin transcripts accumulating in the colon mucosa. We propose that monitoring HP1γ activity and RNA splicing precision can help in the management of IBD and, more generally, of accelerated aging.

Glycogen synthase kinase 3 involvement in the excessive proinflammatory response to LPS in patients with decompensated cirrhosis.

BACKGROUND & AIMS: In decompensated cirrhosis, the early innate immune response to the Toll-like receptor 4 (TLR4) agonist, lipopolysaccharides (LPS), is characterized by a hyper-production of pro-inflammatory cytokines and hypo-production of the anti-inflammatory cytokine IL-10. In LPS-stimulated non-cirrhotic immune cells, the constitutively active glycogen synthase kinase (GSK) 3 favors pro- vs. anti-inflammatory cytokines, by acting on gene induction. However, in these cells, TLR4 dampens its own pro-inflammatory response by inducing early (within minutes) AKT-mediated phosphorylation of GSK3ß (one of two GSK3 isoforms) on Ser9. Phosphorylation of GSK3ß (Ser9) inhibits its activity, decreases pro-inflammatory cytokines, and increases IL-10. Thus, we investigated the role of GSK3 in LPS-induced cytokine production by peripheral blood mononuclear cells (PBMCs) or monocytes from patients with advanced cirrhosis and normal subjects. METHODS: Cells were pre-incubated with or without GSK3 inhibitor (SB216763 or lithium chloride) for 1h and then stimulated with LPS. Cytokine production was assessed at mRNA and secreted proteins levels, by real-time RT-PCR at 1h and ELISA at 20 h, respectively. GSK3ß phosphorylation was assessed using Western blotting. RESULTS: In cirrhotic and normal PBMCs pretreated with GSK3 inhibitors, LPS-induced production of pro-inflammatory proteins TNF-α and IL-12p40 was significantly decreased while that of IL-10 was increased. LPS-induced, AKT-mediated phosphorylation of GSK3ß on Ser9 found in normal monocytes, was abolished in cirrhotic cells. CONCLUSIONS: GSK3 is involved in the early TLR4-mediated pro-inflammatory response in patients with decompensated cirrhosis. This was associated with a defect in AKT-mediated GSK3ß phosphorylation resulting in unrestricted 'pro-inflammatory' activity of the enzyme.

In vivo hepatic endoplasmic reticulum stress in patients with chronic hepatitis C.

In hepatocytes, the accumulation of unfolded proteins in the endoplasmic reticulum (ER) causes ER stress and the unfolded protein response (UPR), mediated by the ER-resident stress sensors ATF-6, IRE1, and PERK. UPR-responsive genes are involved in the fate of ER-stressed cells. Cells carrying hepatitis C virus (HCV) subgenomic replicons exhibit in vitro ER stress and suggest that HCV inhibits the UPR. Since in vivo ER homeostasis is unknown in livers with chronic HCV infection, we investigated ER stress and the UPR in liver samples from untreated patients with chronic hepatitis C (CHC), in comparison with normal livers. Electron microscopy, western blotting, and real-time RT-PCR were used in liver biopsy specimens. Electron microscopy identified features showing ER stress in hepatocyte samples from patients with CHC; however, 'ER-stressed' hepatocytes were found in clusters (3-5 cells) that were scattered in the liver parenchyma. Western blot analysis confirmed the existence of hepatic ER stress by showing activation of the three ER stress sensors ATF-6, IRE1, and PERK in CHC. Real-time RT-PCR showed no significant induction of UPR-responsive genes in CHC. In contrast, genes involved in the control of diffuse processes such as liver proliferation, inflammation, and apoptosis were significantly induced in CHC. In conclusion, livers from patients with untreated CHC exhibit in vivo hepatocyte ER stress and activation of the three UPR sensors without apparent induction of UPR-responsive genes. This lack of gene induction may be explained by the inhibiting action of HCV per se (as suggested by in vitro studies) and/or by our finding of the localized nature of hepatocyte ER stress.

Computational Learning of microRNA-Based Prediction of Pouchitis Outcome After Restorative Proctocolectomy in Patients With Ulcerative Colitis.

BACKGROUND: Ileal pouch-anal anastomosis (IPAA) is the standard of care after total proctocolectomy for ulcerative colitis (UC). However, inflammation often develops in the pouch, leading to acute or recurrent/chronic pouchitis (R/CP). MicroRNAs (miRNA) are used as accurate diagnostic and predictive biomarkers in many human diseases, including inflammatory bowel diseases. Therefore, we aimed to identify an miRNA-based biomarker to predict the occurrence of R/CP in patients with UC after colectomy and IPAA. METHODS: We conducted a retrospective study in 3 tertiary centers in France. We included patients with UC who had undergone IPAA with or without subsequent R/CP. Paraffin-embedded biopsies collected from the terminal ileum during the proctocolectomy procedure were used for microarray analysis of miRNA expression profiles. Deep neural network-based classifiers were used to identify biomarkers predicting R/CP using miRNA expression and relevant biological and clinical factors in a discovery cohort of 29 patients. The classification algorithm was tested in an independent validation cohort of 28 patients. RESULTS: A combination of 11 miRNA expression profiles and 3 biological/clinical factors predicted the outcome of R/CP with 88% accuracy (area under the curve = 0.94) in the discovery cohort. The performance of the classification algorithm was confirmed in the validation cohort with 88% accuracy (area under the curve = 0.90). Apoptosis, cytoskeletal regulation by Rho GTPase, and fibroblast growth factor signaling were the most dysregulated targets of the 11 selected miRNAs. CONCLUSIONS: We developed and validated a computational miRNA-based algorithm for accurately predicting R/CP in patients with UC after IPAA.

Ex vivo effects of high-density lipoprotein exposure on the lipopolysaccharide-induced inflammatory response in patients with severe cirrhosis.

UNLABELLED: High-density lipoproteins (HDL) are known to neutralize lipopolysaccharide (LPS). Because patients with cirrhosis have lower HDL levels, this may contribute to LPS-induced ex vivo monocyte overproduction of proinflammatory cytokines. However, the effects of HDL on cytokine production by monocytes from patients with cirrhosis have never been studied. The aim of this study was to determine the effects of HDL on LPS-induced proinflammatory cytokine production in whole blood and isolated monocytes from patients with severe cirrhosis and controls. Plasma levels of HDL and cytokines were determined. The effects of reconstituted HDL (rHDL) on LPS-induced cytokine production in whole blood were assessed by cytokine array and on tumor necrosis factor alpha (TNF-alpha) and interleukin-10 (IL-10) production in isolated monocytes. Plasma HDL levels were significantly lower in patients with cirrhosis than in controls. Plasma levels of TNF-alpha and IL-6 were significantly higher in patients with cirrhosis than in controls. Incubation of rHDL with whole blood prevented LPS-induced TNF-alpha and IL-6 overproduction in patients with cirrhosis. LPS-induced TNF-alpha production and CD14 expression were significantly more marked in cirrhotic monocytes than in control monocytes, and both decreased significantly after rHDL incubation. LPS-induced down-regulation of scavenger receptor, class B, type I (SR-BI) expression was abolished in cirrhotic monocytes. CONCLUSIONS: This study shows that rHDL abolishes the LPS-induced overproduction of proinflammatory cytokines in whole blood from patients with severe cirrhosis. These results were confirmed in isolated monocytes from these patients. This suggests that administration of rHDL might be a useful strategy for the treatment of cirrhosis to limit LPS-induced cytokine overproduction.

Singular manifolds of proteomic drivers to model the evolution of inflammatory bowel disease status.

The conditions used to describe the presence of an immune disease are often represented by interaction graphs. These informative, but intricate structures are susceptible to perturbations at different levels. The mode in which that perturbation occurs is still of utmost importance in areas such as cell reprogramming and therapeutics models. In this sense, module identification can be useful to well characterise the global graph architecture. To help us with this identification, we perform topological overlap-related measures. Thanks to these measures, the location of highly disease-specific module regulators is possible. Such regulators can perturb other nodes, potentially causing the entire system to change behaviour or collapse. We provide a geometric framework explaining such situations in the context of inflammatory bowel diseases (IBD). IBD are severe chronic disorders of the gastrointestinal tract whose incidence is dramatically increasing worldwide. Our approach models different IBD status as Riemannian manifolds defined by the graph Laplacian of two high throughput proteome screenings. It also identifies module regulators as singularities within the manifolds (the so-called singular manifolds). Furthermore, it reinterprets the characteristic nonlinear dynamics of IBD as compensatory responses to perturbations on those singularities. Then, particular reconfigurations of the immune system could make the disease status move towards an innocuous target state.