PPARG activation promotes the proliferation of colorectal cancer cell lines and enhances the antiproliferative effect of 5-fluorouracil.

BACKGROUND: Peroxisome proliferator-activated receptor gamma (PPARG) is a member of the nuclear receptor family. It is involved in the regulation of adipogenesis, lipid metabolism, insulin sensitivity, vascular homeostasis and inflammation. In addition, PPARG agonists, known as thiazolidinediones, are well established in the treatment of type 2 diabetes mellitus. PPARGs role in cancer is a matter of debate, as pro- and anti-tumour properties have been described in various tumour entities. Currently, the specific role of PPARG in patients with colorectal cancer (CRC) is not fully understood. MATERIAL AND METHODS: The prognostic impact of PPARG expression was investigated by immunohistochemistry in a case-control study using a matched pair selection of CRC tumours (n = 246) with either distant metastases to the liver (n = 82), lung (n = 82) or without distant metastases (n = 82). Its effect on proliferation as well as the sensitivity to the chemotherapeutic drug 5-fluorouracil (5-FU) was examined after activation, inhibition, and transient gene knockdown of PPARG in the CRC cell lines SW403 and HT29. RESULTS: High PPARG expression was significantly associated with pulmonary metastasis (p = 0.019). Patients without distant metastases had a significantly longer overall survival with low PPARG expression in their tumours compared to patients with high PPARG expression (p = 0.045). In the pulmonary metastasis cohort instead, a trend towards longer survival was observed for patients with high PPARG expression in their tumour (p = 0.059). Activation of PPARG by pioglitazone and rosiglitazone resulted in a significant dose-dependent increase in proliferation of CRC cell lines. Inhibition of PPARG by its specific inhibitor GW9662 and siRNA-mediated knockdown of PPARG significantly decreased proliferation. Activating PPARG significantly increased the CRC cell lines sensitivity to 5-FU while its inhibition decreased it. CONCLUSION: The prognostic effect of PPARG expression depends on the metastasis localization in advanced CRC patients. Activation of PPARG increased malignancy associated traits such as proliferation in CRC cell lines but also increases sensitivity towards the chemotherapeutic agent 5-FU. Based on this finding, a combination therapy of PPARG agonists and 5-FU-based chemotherapy constitutes a promising strategy which should be further investigated.

It is not NOD2 - genetic and clinical risk factors for postoperative complications following ileocolic resection in Crohn's disease.

PURPOSE: To evaluate the role of the nucleotide oligomerization domain 2 (NOD2) mutation status and other risk factors for the incidence of postoperative complications after ileocolic resection for Crohn's disease (CD). METHODS: Data of 138 patients consecutively undergoing ileocolic resection for CD at a tertiary academic referral center were retrospectively analyzed including single nucleotide polymorphism (SNP) data of the NOD2 gene. Uni- and multivariate regression analysis was performed to identify factors associated with increased risk of severe postoperative complications. RESULTS: From 114 patients (83%), the NOD2 mutation status was available. Of these, 60 (53%) had a NOD2 wildtype, whereas eleven (10%) were homozygous for the high risk p.Leu1007fsX1008 (rs2066847) variant. Major postoperative complications occurred in 28 patients (20%). Twenty-seven of these (96%) were intraabdominal septic complications such as anastomotic leakage or abscess. Male gender (P = 0.029; OR 3.052, the duration of CD (time [months] from initial diagnosis of CD to surgery; P = 0.001; OR 1.009), previous abdominal surgery for CD (P = 0.017; OR 3.49), and the presence of enteric fistulas (P = 0.023; OR 3.21) were identified as independent risk factors for major postoperative complications. Homozygosity for the NOD2 high-risk variant p.Leu1007fsX1008 did not show increased postoperative morbidity in the short and long-term outcome. CONCLUSIONS: We could detect independent risk factors for major postoperative complications after ileocolic resection for Crohn's disease. However, patients with the high-risk variant p.Leu1007fsX1008 of the NOD2 gene did not show increased postoperative morbidity.

Hydrophobic Bile Salts Induce Pro-Fibrogenic Proliferation of Hepatic Stellate Cells through PI3K p110 Alpha Signaling.

Bile salts accumulating during cholestatic liver disease are believed to promote liver fibrosis. We have recently shown that chenodeoxycholate (CDC) induces expansion of hepatic stellate cells (HSCs) in vivo, thereby promoting liver fibrosis. Mechanisms underlying bile salt-induced fibrogenesis remain elusive. We aimed to characterize the effects of different bile salts on HSC biology and investigated underlying signaling pathways. Murine HSCs (mHSCs) were stimulated with hydrophilic and hydrophobic bile salts. Proliferation, cell mass, collagen deposition, and activation of signaling pathways were determined. Activation of the human HSC cell line LX 2 was assessed by quantification of α-smooth muscle actin (αSMA) expression. Phosphatidyl-inositol-3-kinase (PI3K)-dependent signaling was inhibited both pharmacologically and by siRNA. CDC, the most abundant bile salt accumulating in human cholestasis, but no other bile salt tested, induced Protein kinase B (PKB) phosphorylation and promoted HSC proliferation and subsequent collagen deposition. Pharmacological inhibition of the upstream target PI3K-inhibited activation of PKB and pro-fibrogenic proliferation of HSCs. The PI3K p110α-specific inhibitor Alpelisib and siRNA-mediated knockdown of p110α ameliorated pro-fibrogenic activation of mHSC and LX 2 cells, respectively. In summary, pro-fibrogenic signaling in mHSCs is selectively induced by CDC. PI3K p110α may be a potential therapeutic target for the inhibition of bile salt-induced fibrogenesis in cholestasis.

p70 Ribosomal Protein S6 Kinase Is a Checkpoint of Human Hepatic Stellate Cell Activation and Liver Fibrosis in Mice.

BACKGROUND & AIMS: Progression of chronic liver disease (CLD) to liver cirrhosis and liver cancer is a major global cause of morbidity and mortality. Treatment options capable of inhibiting progression of liver fibrosis when etiological treatment of CLD is not available or fails have yet to be established. We investigated the role of serine/threonine kinase p70 ribosomal protein S6 kinase (p70S6K) as checkpoint of fibrogenesis in hepatic stellate cells (HSCs) and as target for the treatment of liver fibrosis. APPROACH & RESULTS: Immunohistochemistry was used to assess p70S6K expression in liver resection specimen. Primary human or murine HSCs from wild-type or p70S6K-/- mice as well as LX-2 cells were used for in vitro experiments. Specific small interfering RNA or CEP-1347 were used to silence or inhibit p70S6K and assess its functional relevance in viability, contraction and migration assays, fluorescence-activated cell sorting, and Western blot. These results were validated in vivo by a chemical model of fibrogenesis using wild-type and p70S6K-/- mice. Expression of p70S6K was significantly increased in human cirrhotic vs noncirrhotic liver-tissue and progressively increased in vitro through activation of primary human HSCs. Conversely, p70S6K induced fibrogenic activation of HSCs in different models, including the small interfering RNA-based silencing of p70S6K in HSC lines, experiments with p70S6K-/- cells, and the pharmacological inhibition of p70S6K by CEP-1347. These findings were validated in vivo as p70S6K-/- mice developed significantly less fibrosis upon exposure to CCl4. CONCLUSIONS: We establish p70S6K as a checkpoint of fibrogenesis in vitro and in vivo and CEP-1347 as potential treatment option that can safely be used for long-term treatment.

Follistatin-controlled activin-HNF4α-coagulation factor axis in liver progenitor cells determines outcome of acute liver failure.

BACKGROUND AND AIMS: In patients with acute liver failure (ALF) who suffer from massive hepatocyte loss, liver progenitor cells (LPCs) take over key hepatocyte functions, which ultimately determines survival. This study investigated how the expression of hepatocyte nuclear factor 4α (HNF4α), its regulators, and targets in LPCs determines clinical outcome of patients with ALF. APPROACH AND RESULTS: Clinicopathological associations were scrutinized in 19 patients with ALF (9 recovered and 10 receiving liver transplantation). Regulatory mechanisms between follistatin, activin, HNF4α, and coagulation factor expression in LPC were investigated in vitro and in metronidazole-treated zebrafish. A prospective clinical study followed up 186 patients with cirrhosis for 80 months to observe the relevance of follistatin levels in prevalence and mortality of acute-on-chronic liver failure. Recovered patients with ALF robustly express HNF4α in either LPCs or remaining hepatocytes. As in hepatocytes, HNF4α controls the expression of coagulation factors by binding to their promoters in LPC. HNF4α expression in LPCs requires the forkhead box protein H1-Sma and Mad homolog 2/3/4 transcription factor complex, which is promoted by the TGF-ß superfamily member activin. Activin signaling in LPCs is negatively regulated by follistatin, a hepatocyte-derived hormone controlled by insulin and glucagon. In contrast to patients requiring liver transplantation, recovered patients demonstrate a normal activin/follistatin ratio, robust abundance of the activin effectors phosphorylated Sma and Mad homolog 2 and HNF4α in LPCs, leading to significantly improved coagulation function. A follow-up study indicated that serum follistatin levels could predict the incidence and mortality of acute-on-chronic liver failure. CONCLUSIONS: These results highlight a crucial role of the follistatin-controlled activin-HNF4α-coagulation axis in determining the clinical outcome of massive hepatocyte loss-induced ALF. The effects of insulin and glucagon on follistatin suggest a key role of the systemic metabolic state in ALF.

Endoscopic Vacuum Therapy for Left-Sided Colorectal Anastomotic Leak Without Fecal Diversion.

BACKGROUND: Endoscopic vacuum therapy for the treatment of rectal anastomotic leak has been shown to be effective and safe. The majority of patients are treated after fecal diversion to avoid further septic complications. OBJECTIVE: To report the effectiveness of endoscopic vacuum therapy for rectal anastomotic leak without diversion compared to secondary stoma creation. DESIGN: Retrospective cohort analysis. SETTINGS: University hospital, single-center. PATIENTS: Patients undergoing sigmoid or rectal resection without fecal diversion during primary surgery who were treated with endoscopic vacuum therapy for clinically relevant anastomotic leak. MAIN OUTCOME MEASURES: Treatment success (sepsis control, granulation and closure of the leak cavity, and no subsequent interventional or surgical procedure required); treatment duration; complications associated with endoscopic vacuum therapy; outpatient treatment; and restoration of intestinal continuity in diverted patients. RESULTS: Fifty-seven patients were included. In 20 patients (35%), endoscopic vacuum therapy was initiated without secondary diversion since the leak was extraperitoneal, and the sponge could be placed into the leak cavity with an adequate seal toward the lumen. In 18 patients (90%), this approach was successful. None of these patients required subsequent diversion in the further course of their disease. In two patients, secondary diversion was necessary due to treatment failure. Balloon dilatation for luminal stenosis was required in two patients. When comparing patient and treatment characteristics of patients with and without a stoma, including treatment success and duration, no significant differences were found. Restoration of intestinal continuity was achieved in 69% of diverted patients. LIMITATIONS: Unrandomized, retrospective study design; confounding factors of treatment assignment; low patient numbers and short follow-up of diverted patients; and low statistical power. CONCLUSION: In this single-institution study, endoscopic vacuum therapy for rectal anastomotic leak was successful in 90% of patients without diversion with regard to sepsis control, granulation of the leak cavity, avoidance of surgery, and long-term stoma-free survival. See Video Abstract at http://links.lww.com/DCR/B737.TERAPIA ENDOSCÓPICA POR ASPIRACIÓN AL VACÍO EN CASOS DE FUGA ANASTOMÓTICA RECTO-CÓLICA IZQUIERDA SIN OSTOMÍA DE PROTECCIÓNANTECEDENTES:Se ha demostrado que la terapia endoscópica por aspiración al vacío en casos de fuga anastomótica recto-cólica izquierda en el tratamiento de la fuga anastomótica rectal es eficaz y segura. La mayoría de los casos beneficiaron del tratamiento después de la confeción de un ostomía de protección para evitar más complicaciones sépticas.OBJETIVO:Demostrar la efectividad de la terapia endoscópica por aspiración al vacío en casos de fuga anastomótica recto-cólica izquierda sin ostomía de protección comparada con los casos que tuvieron la creación de una ostomía secundaria.DISEÑO:Análisis de cohortes de tipo retrospectivo.AJUSTE:Hospital universitario, unicéntrico.PACIENTES:Aquellos pacientes sometidos a una resección sigmoidea o rectal sin ostomía de protección durante una cirugía primaria, y que fueron tratados con terapia endoscópica por aspiración al vacío en caso de fuga anastomótica clínicamente relevante.PRINCIPALES MEDIDAS DE RESULTADO:Tratamiento exitoso (control de la sepsis, granulación y cierre de la cavidad de la fuga, sin requerir procedimiento quirúrgico o intervención ulteterior); duración del tratamiento; complicaciones asociadas con la terapia endoscópica por aspiración al vacío; tratamiento ambulatorio; restablecimiento de la continuidad intestinal en los pacientes portadores de ostomía.RESULTADOS:Se incluyeron 57 pacientes. En 20 pacientes (35%), se inició la terapia endoscópica por aspiración al vacío sin derivación secundaria, ya que la fuga era extraperitoneal y la esponja podía colocarse en la cavidad de la fuga con un sellado adecuado hacia el lumen. En 18 pacientes (90%), este enfoque fue exitoso. Ninguno de estos pacientes requirió una derivación posterior durante la evolución de la enfermedad. En dos pacientes, fue necesaria una derivación secundaria debido al fracaso del tratamiento. Se requirió dilatación con balón por estenosis luminal en dos pacientes. Al comparar las características de los pacientes y del tratamiento con y sin ostomía, incluido el éxito y la duración del tratamiento, no se encontraron diferencias significativas. El restablecimiento de la continuidad intestinal se logró en el 69% de los pacientes derivados.LIMITACIONES:Diseño de estudio retrospectivo no aleatorio; factores de confusión en la asignación del tratamiento; escaso número de pacientes y seguimiento a corto plazo de los pacientes ostomizados; bajo poder estadístico.CONCLUSIÓN:En este estudio de una sola institución, la terapia al vacío por vía endoscópica en casos de fuga anastomótica rectal fue exitosa en el 90% de los pacientes sin derivación con respecto al control de la sepsis, granulación de la cavidad de la fuga, como se evitó la cirugía y la sobrevida sin ostomía a largo plazo. Consulte Video Resumen en http://links.lww.com/DCR/B737. (Traducción-Dr. Xavier Delgadillo).

Endoscopic vacuum therapy for the treatment of colorectal leaks - a systematic review and meta-analysis.

BACKGROUND: During the last two decades, vacuum-assisted wound therapy has been successfully transferred to an endoscopic treatment approach of various upper and lower gastrointestinal leaks called endoscopic vacuum therapy (EVT). As mostly small case series are published in this field, the aim of our systematic review and meta-analysis was to evaluate the efficacy and safety of EVT in the treatment of colorectal leaks. METHODS: A systematic search of MEDLINE/PubMed and Cochrane databases was performed using search terms related to EVT and colorectal defects (anastomotic leakage, rectal stump insufficiency) according to the PRISMA guidelines. Randomized controlled trials (RCTs), observational studies, and case series published by December 2020 were eligible for inclusion. A meta-analysis was conducted on the success of EVT, stoma reversal rate after EVT as well as procedure-related complications. Statistical interferences were based on pooled estimates from random effects models using DerSimonian-Laird estimator. RESULTS: Only data from observational studies and case series were available. Twenty-four studies reporting on 690 patients with colorectal defects undergoing EVT were included. The mean rate of success was 81.4% (95% CI: 74.0%-87.1%). The proportion of diverted patients was 76.4% (95% CI: 64.9%-85.0%). The mean rate of ostomy reversal across the studies was 66.7% (95% CI: 58.0%-74.4%). Sixty-four patients were reported with EVT-associated complications, the weighted mean complication rate across the studies was 12.1% (95% CI: 9.7%-15.2%). CONCLUSIONS: Current medical evidence on EVT in patients with colorectal leaks lacks high quality data from RCTs. Based on the data available, EVT can be seen as a feasible treatment option with manageable risks for selected patients with colorectal leaks.

Targeting the Intestinal Barrier to Prevent Gut-Derived Inflammation and Disease: A Role for Intestinal Alkaline Phosphatase.

BACKGROUND: Intestinal alkaline phosphatase (IAP) as a tissue-specific isozyme of alkaline phosphatases is predominantly produced by enterocytes in the proximal small intestine. In recent years, an increasing number of pathologies have been identified to be associated with an IAP deficiency, making it very worthwhile to review the various roles, biological functions, and potential therapeutic aspects of IAP. SUMMARY: IAP primarily originates and acts in the intestinal tract but affects other organs through specific biological axes related to its fundamental roles such as promoting gut barrier function, dephosphorylation/detoxification of lipopolysaccharides (LPS), and regulation of gut microbiota. KEY MESSAGES: Numerous studies reporting on the different roles and the potential therapeutic value of IAP across species have been published during the last decade. While IAP deficiency is linked to varying degrees of physiological dysfunctions across multiple organ systems, the supplementation of IAP has been proven to be beneficial in several translational and clinical studies. The increasing evidence of the salutary functions of IAP underlines the significance of the naturally occurring brush border enzyme.

Epigenomic and transcriptional profiling identifies impaired glyoxylate detoxification in NAFLD as a risk factor for hyperoxaluria.

Epigenetic modifications (e.g. DNA methylation) in NAFLD and their contribution to disease progression and extrahepatic complications are poorly explored. Here, we use an integrated epigenome and transcriptome analysis of mouse NAFLD hepatocytes and identify alterations in glyoxylate metabolism, a pathway relevant in kidney damage via oxalate release-a harmful waste product and kidney stone-promoting factor. Downregulation and hypermethylation of alanine-glyoxylate aminotransferase (Agxt), which detoxifies glyoxylate, preventing excessive oxalate accumulation, is accompanied by increased oxalate formation after metabolism of the precursor hydroxyproline. Viral-mediated Agxt transfer or inhibiting hydroxyproline catabolism rescues excessive oxalate release. In human steatotic hepatocytes, AGXT is also downregulated and hypermethylated, and in NAFLD adolescents, steatosis severity correlates with urinary oxalate excretion. Thus, this work identifies a reduced capacity of the steatotic liver to detoxify glyoxylate, triggering elevated oxalate, and provides a mechanistic explanation for the increased risk of kidney stones and chronic kidney disease in NAFLD patients.

Secondary resistance to anti-EGFR therapy by transcriptional reprogramming in patient-derived colorectal cancer models.

BACKGROUND: The development of secondary resistance (SR) in metastatic colorectal cancer (mCRC) treated with anti-epidermal growth factor receptor (anti-EGFR) antibodies is not fully understood at the molecular level. Here we tested in vivo selection of anti-EGFR SR tumors in CRC patient-derived xenograft (PDX) models as a strategy for a molecular dissection of SR mechanisms. METHODS: We analyzed 21 KRAS, NRAS, BRAF, and PI3K wildtype CRC patient-derived xenograft (PDX) models for their anti-EGFR sensitivity. Furthermore, 31 anti-EGFR SR tumors were generated via chronic in vivo treatment with cetuximab. A multi-omics approach was employed to address molecular primary and secondary resistance mechanisms. Gene set enrichment analyses were used to uncover SR pathways. Targeted therapy of SR PDX models was applied to validate selected SR pathways. RESULTS: In vivo anti-EGFR SR could be established with high efficiency. Chronic anti-EGFR treatment of CRC PDX tumors induced parallel evolution of multiple resistant lesions with independent molecular SR mechanisms. Mutations in driver genes explained SR development in a subgroup of CRC PDX models, only. Transcriptional reprogramming inducing anti-EGFR SR was discovered as a common mechanism in CRC PDX models frequently leading to RAS signaling pathway activation. We identified cAMP and STAT3 signaling activation, as well as paracrine and autocrine signaling via growth factors as novel anti-EGFR secondary resistance mechanisms. Secondary resistant xenograft tumors could successfully be treated by addressing identified transcriptional changes by tailored targeted therapies. CONCLUSIONS: Our study demonstrates that SR PDX tumors provide a unique platform to study molecular SR mechanisms and allow testing of multiple treatments for efficient targeting of SR mechanisms, not possible in the patient. Importantly, it suggests that the development of anti-EGFR tolerant cells via transcriptional reprogramming as a cause of anti-EGFR SR in CRC is likely more prevalent than previously anticipated. It emphasizes the need for analyses of SR tumor tissues at a multi-omics level for a comprehensive molecular understanding of anti-EGFR SR in CRC.

Experimental postoperative ileus: is Th2 immune response involved?

Rationale: Postoperative ileus (POI) is a frequent complication arising after gastrointestinal surgery but pathogenesis of POI is still not fully understood. While Th1 immune cells are implicated in POI, the involvement of Th2 cells has not yet been clarified. Given the impact of reactive oxygen species (ROS) in the regulation of Th1 and Th2 balance, we hypothesized that not only Th1 but also Th2 immune response can be involved in the development of experimental POI. Methods: The intestinal transit test was performed using carbon gum arabic. Electron microscopy was employed to assess tissue morphology and the presence of immune cells. Cytokines, IgE and ROS were measured. Immune cells from Peyer's patches were analyzed by Flow Cytometry and toluidine blue staining was used for detection of mast cells. Transcriptional factors were analyzed by Western blot. Results: POI is associated with an increase in both Th2 cytokines and Th2 cells. We have further demonstrated that POI induces a Th2-dependent activation of memory and non-memory B cells. This was accompanied by an increase in a number of mast cells in the colon of POI mice as well by an increased IgE and histamine plasma levels. We found that POI-induced accumulation of ROS was associated with an increased expression of the transcriptional factors HMBGI, NF-κB, and p38. This increased expression seemed to be associated with a Th2 response. Conclusion: Th2 immune response can be involved in the activation of mast cells in POI, which was associated with ROS mediated activation of NF-κB and p38 MAPK signaling pathway.

The predictive value of tumor infiltrating leukocytes in Hepatocellular Carcinoma: A systematic review and meta-analysis.

BACKGROUND: For Hepatocellular carcinoma (HCC) surgery either through resection or transplantation often provides the only chance for cure. Since hepatocarcinogenesis and postsurgical prognosis is not only dependent on cirrhosis but also on immune activation and exhaustion, many studies have investigated tumor infiltrating leukocyte (TIL) subsets. This systematic review and meta-analysis aims at describing the cell groups and their predictive power regarding overall (OS), disease free (DFS) and recurrence free survival (RFS). MATERIAL AND METHODS: A systematic search of the PubMed database was conducted (PROSPERO 172324). Data on CD3+, CD8+, Treg, B cells, macrophages, neutrophil and NK-cells were collected from Pubmed and related references up to December 2018. Overall (OS), disease-free (DFS) and recurrence free survival (RFS) in dependence of high vs. low infiltration rates were compared using a random effects meta-analysis. RESULTS: Altogether data from 3541 patients enrolled in 20 publications were included. Except for Tregs and Neutrophils, heterogeneity analysis was found to be moderate to high across the studies. High CD3+, CD8+, NK-cell infiltration predicted better survival (OS, DFS and RFS; p < 0.05). Higher Treg and Neutrophil infiltration predicted lower OS and DFS. For Macrophages and B cells no difference in survival could be found. DISCUSSION: As with other solid tumors immune infiltration has a great influence on survival after resection. However, a considerable publication bias cannot be ruled out in mostly retrospective analyses. Nevertheless, in light of novel immune modulatory treatments this opens a new avenue towards effective and well-tolerated adjuvant treatment.

Chances, challenges and outcomes of patients with complex bilobar colorectal liver metastases approached by a combined multimodal therapy with liver resection and local ablative therapy.

BACKGROUND AND OBJECTIVES: In treatment of colorectal liver metastases (CRC-LM), liver surgery combined with systemic therapies and local ablation (LAT) allows improved survival. This study aims at the outcomes of patients with complex bilobar CRC-LM who were intended to undergo multimodal therapy with liver resection and LAT. METHODS: Forty-three CRC-LM patients with recommendation for multimodal treament were extracted from 5878 tumor board decisions between 2014 and 2017. Outcome variables included patient survival, as well as completion of hepatic clearance. Prognostic factors were identified by correlation and a Cox proportional hazards model. RESULTS: Out of 43 patients only 23 achieved complete clearance of CRC-LM. One- and 3-year overall survival of patients with cleared liver disease was 100% and 91.7%, respectively, as compared to 83.8% and 12.1%. Incomplete hepatic clearance was the strongest independent risk factor for overall survival (hazards ratio [HR], 5.86; p = .009). Risk factors for incomplete clearance were higher age (r = .34; p = .026), comorbidities (r = .40; p = .008), major complications (r = .34; p = .024), and prolonged intensive care unit stay (r = .41; p = .017). CONCLUSION: Completion of hepatic clearance is crucial to achieve long-term survival in patients with complex bilobar CRC-LM. Careful patient selection and treatment planning should avoid treatment failure before completing the intended therapy plan when multimodal treatments are planned.

Nelfinavir and Its Active Metabolite M8 Are Partial Agonists and Competitive Antagonists of the Human Pregnane X Receptor.

The HIV protease inhibitor nelfinavir is currently being analyzed for repurposing as an anticancer drug for many different cancers because it exerts manifold off-target protein interactions, finally resulting in cancer cell death. Xenosensing pregnane X receptor (PXR), which also participates in the control of cancer cell proliferation and apoptosis, was previously shown to be activated by nelfinavir; however, the exact molecular mechanism is still unknown. The present study addresses the effects of nelfinavir and its major and pharmacologically active metabolite nelfinavir hydroxy-tert-butylamide (M8) on PXR to elucidate the underlying molecular mechanism. Molecular docking suggested direct binding to the PXR ligand-binding domain, which was confirmed experimentally by limited proteolytic digestion and competitive ligand-binding assays. Concentration-response analyses using cellular transactivation assays identified nelfinavir and M8 as partial agonists with EC50 values of 0.9 and 7.3 µM and competitive antagonists of rifampin-dependent induction with IC50 values of 7.5 and 25.3 µM, respectively. Antagonism exclusively resulted from binding into the PXR ligand-binding pocket. Impaired coactivator recruitment by nelfinavir as compared with the full agonist rifampin proved to be the underlying mechanism of both effects on PXR. Physiologic relevance of nelfinavir-dependent modulation of PXR activity was investigated in respectively treated primary human hepatocytes, which showed differential induction of PXR target genes and antagonism of rifampin-induced ABCB1 and CYP3A4 gene expression. In conclusion, we elucidate here the molecular mechanism of nelfinavir interaction with PXR. It is hypothesized that modulation of PXR activity may impact the anticancer effects of nelfinavir. SIGNIFICANCE STATEMENT: Nelfinavir, which is being investigated for repurposing as an anticancer medication, is shown here to directly bind to human pregnane X receptor (PXR) and thereby act as a partial agonist and competitive antagonist. Its major metabolite nelfinavir hydroxy-tert-butylamide exerts the same effects, which are based on impaired coactivator recruitment. Nelfinavir anticancer activity may involve modulation of PXR, which itself is discussed as a therapeutic target in cancer therapy and for the reversal of chemoresistance.

Endoscopic vacuum therapy for treatment of rectal stump leakage.

BACKGROUND: Symptomatic rectal stump leakage (RSL) is a serious complication after discontinuity resection and requires immediate surgical, interventional, or endoscopic therapy. Re-operations are associated with high morbidity and mortality in these mostly very ill patients. Endoscopic vacuum therapy (EVT) has been established for management of anastomotic leakage; however, its effectiveness for RSL treatment has not been analyzed in detail yet. METHODS: A retrospective analysis of patients treated with EVT for RSL between 2001 and 2018 analyzing factors predicting therapy success and duration was carried out. RESULTS: Fifty-six patients with RSL at a median age of 66 years were included. Of these, 18 patients (32%) had been referred for EVT from external departments or institutions. RSL was associated with a relevant clinical deterioration in all patients, and 55 patients (98%) had been classified as ASA 3 and 4, preoperatively. In 9 patients (16%), additional surgical revision was necessary with initiation of EVT. In 47 patients (84%), EVT was successful and local control of the inflammatory focus was achieved. The median duration of therapy was 20 days. Two patients (4%) suffered from minor EVT-associated bleeding that was endoscopically controlled. Preoperative radiation of the pelvis was significantly associated with EVT failure (P = 0.035), whereas patient age represented a predictive factor for therapy length (P = 0.039). In 12 patients (21%), restoration of intestinal continuity was achieved in the further course. CONCLUSIONS: We present the first specific series on EVT for RSL. EVT for RSL was shown to be an effective and safe minimal-invasive treatment option, avoiding surgical revision in the majority of patients.

Endoscopic vacuum therapy for in- and outpatient treatment of colorectal defects.

BACKGROUND: Evidence for endoscopic vacuum therapy (EVT) for colorectal defects is still based on small patient series from various institutions, employing different treatment algorithms and methods. As EVT was invented at our institution 20 years ago, the aim was to report the efficacy and safety of EVT for colorectal defects as well as to analyze factors associated with efficacy, therapy duration, and outpatient treatment. METHODS: Cohort study with analysis of prospectively collected data of patients receiving EVT for colorectal defects at a tertiary referral center in Germany (n = 281). RESULTS: The majority of patients had malignant disease (83%) and an American Society of Anesthesiologists classification of III/IV (81%). Most frequent indications for EVT were anastomotic leakage after sigmoid or rectal resection (67%) followed by rectal stump leakage (20%). EVT was successful in 256 out of 281 patients (91%). EVT following multi-visceral resection (P = 0.037) and recent surgical revision after primary surgery (P = 0.009) were risk factors for EVT failure. EVT-associated adverse events occurred in 27 patients (10%). Median treatment duration was 25 days. Previous chemo-radiation (P = 0.006) was associated with a significant longer duration of EVT. Outpatient treatment was conducted in 49% of patients with a median hospital stay reduction of 15 days and 98% treatment success. Younger patient age (P = 0.044) was associated with the possibility of outpatient treatment. Restoration of intestinal continuity was achieved in 60% of patients where technically possible with a 12-month rate of 52%. CONCLUSIONS: In patients with colorectal defects, EVT appears to be a safe and effective, minimally invasive option for in- and outpatient treatment.

Pancreatic panniculitis and elevated serum lipase in metastasized acinar cell carcinoma of the pancreas: A case report and review of literature.

BACKGROUND: Pancreatic panniculitis is an extremely rare condition associated with different underlying pancreatic disorders and characterized by subcutaneous fat necrosis induced by elevated serum lipase levels. These lesions usually affect the lower extremities and may precede abdominal symptoms of pancreatic disease. Acinar cell carcinoma (ACC) of the pancreas is a rare pancreatic neoplasm, accounting for only 1%-2% of pancreatic tumors in adults. CASE SUMMARY: We present the case of a 72-year-old man with ACC of the pancreatic head and synchronous liver metastases. Both the primary tumor and liver metastases were resected. Serum lipase was elevated before surgery and decreased to normal postoperatively. Rising serum lipase levels at follow-up led to the diagnosis of hepatic recurrence. This disease progression was then accompanied by pancreatic panniculitis, with subcutaneous fat necrosis and acute arthritis. To the best of our knowledge, only 4 cases have been reported in the literature and each showed a similar association of serum lipase levels with pancreatic panniculitis and progression of ACC. CONCLUSION: Clinical symptoms and progression of ACC may correlate with serum lipase levels, suggesting potential usefulness as a follow-up biomarker.

Microbiome Analysis from Paired Mucosal and Fecal Samples of a Colorectal Cancer Biobank.

The role of gut microbiota in colorectal cancer is subject to extensive research. Before usage of biorepositories for microbiome studies, it is crucial to evaluate technical feasibility of microbiome profiling from various biospecimens. The aim of this study was to assess the feasibility of DNA-extraction and microbiome profiling of samples from different sample sites, tissue sites and storage duration of a colorectal cancer biobank. Mucosa samples, mucosal scrapings and feces as well as different tissue sites (tumor, normal mucosa) were analyzed. 16S rRNA gene-based microbiome profiling with taxonomic assignment was performed on the Illumina MiSeq (Illumina, San Diego, USA) platform from stored snap frozen samples. For statistical analysis, α- and ß-diversity measures, PCoA, permutational multivariate analysis of variance and graphical representation were performed. Microbiome analysis could be successfully performed in most of the samples (overall 93.3%) with sufficient numbers of high-quality reads. There were no differences between sample sites, while in some measures significant differences were found between tumor and normal mucosa (α-diversity, Shannon/Simpson Indices p = 0.028/0.027, respectively). Samples stored for up to eight years were used and storage conditions had no significant influence on the results. Tumor and tissue samples of a biobank stored long term can be successfully used for microbiome analysis. As large sample sizes are needed for association studies to evaluate microbial impact on tumorigenesis or progression of colorectal cancer, an already established biorepository may be a useful alternative to prospective clinical studies.

IL-18 but Not IL-1 Signaling Is Pivotal for the Initiation of Liver Injury in Murine Non-Alcoholic Fatty Liver Disease.

Non-alcoholic fatty liver disease (NAFLD) is rising in prevalence, and a better pathophysiologic understanding of the transition to its inflammatory phenotype (NASH) is key to the development of effective therapies. To evaluate the contribution of the NLRP3 inflammasome and its downstream effectors IL-1 and IL-18 in this process, we applied the true-to-life "American lifestyle-induced obesity syndrome" (ALiOS) diet mouse model. Development of obesity, fatty liver and liver damage was investigated in mice fed for 24 weeks according to the ALiOS protocol. Lipidomic changes in mouse livers were compared to human NAFLD samples. Receptor knockout mice for IL-1 and IL-18 were used to dissect the impact of downstream signals of inflammasome activity on the development of NAFLD. The ALiOS diet induced obesity and liver steatosis. The lipidomic changes closely mimicked changes in human NAFLD. A pro-inflammatory gene expression pattern in liver tissue and increased serum liver transaminases indicated early liver damage in the absence of histological evidence of NASH. Mechanistically, Il-18r-/-- but not Il-1r-/- mice were protected from early liver damage, possibly due to silencing of the pro-inflammatory gene expression pattern. Our study identified NLRP3 activation and IL-18R-dependent signaling as potential modulators of early liver damage in NAFLD, preceding development of histologic NASH.

Specific Management of Patients with Acute Abdomen during the COVID-19 Pandemic: A Surgical Perspective from Germany.

During the current COVID-19 pandemic, the triage, assessment, and management of patients presenting to the emergency department with critical conditions has become -challenging. The clinical features of COVID-19 are heterogeneous and subtle in many cases. They may easily be overlooked in the case of other acute diseases. Gastrointestinal symptoms are common in patients with COVID-19 as SARS-CoV-2 is able to enter gastrointestinal epithelial cells. However, these complaints can also be caused by a COVID-19-independent concomitant abdominal pathology. Therefore, patients with acute abdominal pain and fever need to be assessed very thoroughly. Based on a clinical case, we present our approach of managing emergency patients with acute abdomen and concomitant suspicion of -COVID-19.