Incidence, diagnosis, management and outcome of acute mesenteric ischaemia: a prospective, multicentre observational study (AMESI Study)

BACKGROUND

The aim of this multicentre prospective observational study was to identify the incidence, patient characteristics, diagnostic pathway, management and outcome of acute mesenteric ischaemia (AMI).

METHODS

All adult patients with clinical suspicion of AMI admitted or transferred to 32 participating hospitals from 06.06.2022 to 05.04.2023 were included. Participants who were subsequently shown not to have AMI or had localized intestinal gangrene due to strangulating bowel obstruction had only baseline and outcome data collected.

RESULTS

AMI occurred in 0.038% of adult admissions in participating acute care hospitals worldwide. From a total of 705 included patients, 418 patients had confirmed AMI. In 69% AMI was the primary reason for admission, while in 31% AMI occurred after having been admitted with another diagnosis. Median time from onset of symptoms to hospital admission in patients admitted due to AMI was 24 h (interquartile range 9-48h) and time from admission to diagnosis was 6h (1-12 h). Occlusive arterial AMI was diagnosed in 231 (55.3%), venous in 73 (17.5%), non-occlusive (NOMI) in 55 (13.2%), other type in 11 (2.6%) and the subtype could not be classified in 48 (11.5%) patients. Surgery was the initial management in 242 (58%) patients, of which 59 (24.4%) underwent revascularization. Endovascular revascularization alone was carried out in 54 (13%), conservative treatment in 76 (18%) and palliative care in 46 (11%) patients. From patients with occlusive arterial AMI, revascularization was undertaken in 104 (45%), with 40 (38%) of them in one site admitting selected patients. Overall in-hospital and 90-day mortality of AMI was 49% and 53.3%, respectively, and among subtypes was lowest for venous AMI (13.7% and 16.4%) and highest for NOMI (72.7% and 74.5%). There was a high variability between participating sites for most variables studied.

CONCLUSIONS

The overall incidence of AMI and AMI subtypes varies worldwide, and case ascertainment is challenging. Pre-hospital delay in presentation was greater than delays after arriving at hospital. Surgery without revascularization was the most common management approach. Nearly half of the patients with AMI died during their index hospitalization. Together, these findings suggest a need for greater awareness of AMI, and better guidance in diagnosis and management.

TRIAL REGISTRATION

NCT05218863 (registered 19.01.2022).

Kynurenine monooxygenase regulates inflammation during critical illness and recovery in experimental acute pancreatitis

Kynurenine monooxygenase (KMO) blockade protects against multiple organ failure caused by acute pancreatitis (AP), but the link between KMO and systemic inflammation has eluded discovery until now. Here, we show that the KMO product 3-hydroxykynurenine primes innate immune signaling to exacerbate systemic inflammation during experimental AP. We find a tissue-specific role for KMO, where mice lacking Kmo solely in hepatocytes have elevated plasma 3-hydroxykynurenine levels that prime inflammatory gene transcription. 3-Hydroxykynurenine synergizes with interleukin-1β to cause cellular apoptosis. Critically, mice with elevated 3-hydroxykynurenine succumb fatally earlier and more readily to experimental AP. Therapeutically, blockade with the highly selective KMO inhibitor GSK898 rescues the phenotype, reducing 3-hydroxykynurenine and protecting against critical illness and death. Together, our findings establish KMO and 3-hydroxykynurenine as regulators of inflammation and the innate immune response to sterile inflammation. During critical illness, excess morbidity and death from multiple organ failure can be rescued by systemic KMO blockade.

The role of the circadian rhythms in critical illness with a focus on acute pancreatitis

Circadian rhythms are responsible for governing various physiological processes, including hormone secretion, immune responses, metabolism, and the sleep/wake cycle. In critical illnesses such as acute pancreatitis (AP), circadian rhythms can become dysregulated due to disease. Evidence suggests that time of onset of disease, coupled with peripheral inflammation brought about by AP will impact on the circadian rhythms generated in the central pacemaker and peripheral tissues. Cells of the innate and adaptive immune system are governed by circadian rhythms and the diurnal pattern of expression can be disrupted during disease. Peak circadian immune cell release and gene expression can coincide with AP onset, that may increase pancreatic injury, tissue damage and the potential for systemic inflammation and multiple organ failure to develop. Here, we provide an overview of the role of circadian rhythms in AP and the underpinning inflammatory mechanisms to contextualise ongoing research into the chronobiology and chronotherapeutics of AP.

Increased risk of type 3c diabetes mellitus after acute pancreatitis warrants a personalized approach including diabetes screening

BACKGROUND

Acute pancreatitis (AP) is a frequent cause of hospitalization with long-term health consequences, including type 3c diabetes mellitus (DM). The incidence and risk factors for new-onset morbidities after AP need to be clarified to inform a personalized medicine approach.

METHODS

Using a longitudinal electronic healthcare record-linkage analysis, all patients admitted to hospital in Scotland with a first episode of AP between 1 April 2009 and 31 March 2012 and followed for a minimum of 5 years after their index AP admission were identified. All new-onset morbidity with specific focus on type 3c DM were analysed and, using time-split multiple regression.

RESULTS

A total of 2047 patients were included. AP requiring critical care was followed by 2 years of heightened risk (HR 5.24) of developing type 3c DM, increased risk of new-onset cardiac disease (HR 1.61), and renal disease (HR 2.96). The additional risk conferred by critical care AP had a negative interaction with time, whereas additional risk associated with male sex and a non-gallstone aetiology was long lasting.

CONCLUSION

Based on these findings, a personalized approach to include type 3c DM screening for a minimum of 2 years for individuals who required critical care when hospitalized with AP is recommended.

Molecular Patterns in Acute Pancreatitis Reflect Generalizable Endotypes of the Host Response to Systemic Injury in Humans

OBJECTIVE

Acute Pancreatitis (AP) is sudden onset pancreas inflammation that causes systemic injury with a wide and markedly heterogeneous range of clinical consequences. Here, we hypothesized that this observed clinical diversity corresponds to diversity in molecular subtypes that can be identified in clinical and multiomics data.

SUMMARY BACKGROUND DATA

Observational cohort study. n = 57 for the discovery cohort (clinical, transcriptomics, proteomics, and metabolomics data) and n = 312 for the validation cohort (clinical and metabolomics data).

METHODS

We integrated coincident transcriptomics, proteomics, and metabolomics data at serial time points between admission to hospital and up to 48 hours after recruitment from a cohort of patients presenting with acute pancreatitis. We systematically evaluated 4 different metrics for patient similarity using unbiased mathematical, biological, and clinical measures of internal and external validity.We next compared the AP molecular endotypes with previous descriptions of endotypes in a critically ill population with acute respiratory distress syndrome (ARDS).

RESULTS

Our results identify 4 distinct and stable AP molecular endotypes. We validated our findings in a second independent cohort of patients with AP.We observed that 2 endotypes in AP recapitulate disease endotypes previously reported in ARDS.

CONCLUSIONS

Our results show that molecular endotypes exist in AP and reflect biological patterns that are also present in ARDS, suggesting that generalizable patterns exist in diverse presentations of critical illness.

Inhibition of 11β-HSD1 Ameliorates Cognition and Molecular Detrimental Changes after Chronic Mild Stress in SAMP8 Mice

Impaired glucocorticoid (GC) signaling is a significant factor in aging, stress, and neurodegenerative diseases such as Alzheimer's disease. Therefore, the study of GC-mediated stress responses to chronic moderately stressful situations, which occur in daily life, is of huge interest for the design of pharmacological strategies toward the prevention of neurodegeneration. To address this issue, SAMP8 mice were exposed to the chronic mild stress (CMS) paradigm for 4 weeks and treated with RL-118, an 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) inhibitor. The inhibition of this enzyme is linked with a reduction in GC levels and cognitive improvement, while CMS exposure has been associated with reduced cognitive performance. The aim of this project was to assess whether RL-118 treatment could reverse the deleterious effects of CMS on cognition and behavioral abilities and to evaluate the molecular mechanisms that compromise healthy aging in SAMP8 mice. First, we confirmed the target engagement between RL-118 and 11β-HSD1. Additionally, we showed that DNA methylation, hydroxymethylation, and histone phosphorylation were decreased by CMS induction, and increased by RL-118 treatment. In addition, CMS exposure caused the accumulation of reactive oxygen species (ROS)-induced damage and increased pro-oxidant enzymes-as well as pro-inflammatory mediators-through the NF-κB pathway and astrogliosis markers, such as GFAP. Of note, these modifications were reversed by 11β-HSD1 inhibition. Remarkably, although CMS altered mTORC1 signaling, autophagy was increased in the SAMP8 RL-118-treated mice. We also showed an increase in amyloidogenic processes and a decrease in synaptic plasticity and neuronal remodeling markers in mice under CMS, which were consequently modified by RL-118 treatment. In conclusion, 11β-HSD1 inhibition through RL-118 ameliorated the detrimental effects induced by CMS, including epigenetic and cognitive disturbances, indicating that GC-excess attenuation shows potential as a therapeutic strategy for age-related cognitive decline and AD.

Prostaglandin E2 promotes intestinal inflammation via inhibiting microbiota-dependent regulatory T cells

The gut microbiota fundamentally regulates intestinal homeostasis and disease partially through mechanisms that involve modulation of regulatory T cells (Tregs), yet how the microbiota-Treg cross-talk is physiologically controlled is incompletely defined. Here, we report that prostaglandin E2 (PGE2), a well-known mediator of inflammation, inhibits mucosal Tregs in a manner depending on the gut microbiota. PGE2 through its receptor EP4 diminishes Treg-favorable commensal microbiota. Transfer of the gut microbiota that was modified by PGE2-EP4 signaling modulates mucosal Treg responses and exacerbates intestinal inflammation. Mechanistically, PGE2-modified microbiota regulates intestinal mononuclear phagocytes and type I interferon signaling. Depletion of mononuclear phagocytes or deficiency of type I interferon receptor diminishes PGE2-dependent Treg inhibition. Together, our findings provide emergent evidence that PGE2-mediated disruption of microbiota-Treg communication fosters intestinal inflammation.

Quantitative multiparametric MRI allows safe surgical planning in patients undergoing liver resection for colorectal liver metastases: report of two patients

It is not uncommon for clinicians to encounter varying degrees of hepatic steatosis in patients undergoing resection for colorectal liver metastases (CRLM). Magnetic resonance imaging is currently the preferred investigation for identification and pre-operative planning of these patients. An objective assessment of liver quality and degree of steatosis is paramount for planning a safe resection, which is seldom provided by routine MRI sequences. We studied two patients who underwent an additional pre-operative multiparametric MRI scan (LiverMultiScan^TM) as a part of an observational clinical trial (HepaT1ca, NCT03213314) to assess the quality of liver. Outcome was assessed in the form of post-hepatectomy liver failure. Both patients (Patient 1 and 2) had comparable pre-operative characteristics. Both patients were planned for an extended right hepatectomy with an estimated future liver remnant of approximately 30%. Conventional preoperative contrast MRI showed mild liver steatosis in both patients. Patient one developed post-hepatectomy liver failure leading to prolonged hospital stay compared to patient two who had uneventful post-operative course. Retrospective evaluation of multiparametric MRI scan revealed findings consistent with fibro-inflammatory disease and steatosis (cT1 829 ms, PDFF 14%) for patient 1 whereas patient two had normal parameters (cT1 735 ms, PDFF 2.4%). These findings corresponded with the resection specimen histology. Multiparametric MRI can objectively evaluate future liver health and volume which may help refine surgical decision-making and improve patient outcomes.

Study protocol for resolution of organ injury in acute pancreatitis (RESORP): an observational prospective cohort study

INTRODUCTION

Survivors of acute pancreatitis (AP) have shorter overall survival and increased incidence of new-onset cardiovascular, respiratory, liver and renal disease, diabetes mellitus and cancer compared with the general population, but the mechanisms that explain this are yet to be elucidated. Our aim is to characterise the precise nature and extent of organ dysfunction following an episode of AP.

METHODS AND ANALYSIS

This is an observational prospective cohort study in a single centre comprising a University hospital with an acute and emergency receiving unit and clinical research facility. Participants will be adult patient admitted with AP. Participants will undergo assessment at recruitment, 3 months and 3 years. At each time point, multiple biochemical and/or physiological assessments to measure cardiovascular, respiratory, liver, renal and cognitive function, diabetes mellitus and quality of life. Recruitment was from 30 November 2017 to 31 May 2020; last follow-up measurements is due on 31 May 2023. The primary outcome measure is the incidence of new-onset type 3c diabetes mellitus during follow-up. Secondary outcome measures include: quality of life analyses (SF-36, Gastrointestinal Quality of Life Index); montreal cognitive assessment; organ system physiological performance; multiomics predictors of AP severity, detection of premature cellular senescence. In a nested cohort within the main cohort, individuals may also consent to multiparameter MRI scan, echocardiography, pulmonary function testing, cardiopulmonary exercise testing and pulse-wave analysis.

ETHICS AND DISSEMINATION

This study has received the following approvals: UK IRAS Number 178615; South-east Scotland Research Ethics Committee number 16/SS/0065. Results will be made available to AP survivors, caregivers, funders and other researchers. Publications will be open-access.

TRIAL REGISTRATION NUMBERS

ClinicalTrials.gov Registry (NCT03342716) and ISRCTN50581876; Pre-results.

Quantitative magnetic resonance imaging predicts individual future liver performance after liver resection for cancer

The risk of poor post-operative outcome and the benefits of surgical resection as a curative therapy require careful assessment by the clinical care team for patients with primary and secondary liver cancer. Advances in surgical techniques have improved patient outcomes but identifying which individual patients are at greatest risk of poor post-operative liver performance remains a challenge. Here we report results from a multicentre observational clinical trial (ClinicalTrials.gov NCT03213314) which aimed to inform personalised pre-operative risk assessment in liver cancer surgery by evaluating liver health using quantitative multiparametric magnetic resonance imaging (MRI). We combined estimation of future liver remnant (FLR) volume with corrected T1 (cT1) of the liver parenchyma as a representation of liver health in 143 patients prior to treatment. Patients with an elevated preoperative liver cT1, indicative of fibroinflammation, had a longer post-operative hospital stay compared to those with a cT1 within the normal range (6.5 vs 5 days; p = 0.0053). A composite score combining FLR and cT1 predicted poor liver performance in the 5 days immediately following surgery (AUROC = 0.78). Furthermore, this composite score correlated with the regenerative performance of the liver in the 3 months following resection. This study highlights the utility of quantitative MRI for identifying patients at increased risk of poor post-operative liver performance and a longer stay in hospital. This approach has the potential to inform the assessment of individualised patient risk as part of the clinical decision-making process for liver cancer surgery.

Co-treatments to Boost IDO Activity and Inhibit Production of Downstream Catabolites Induce Durable Suppression of Experimental Autoimmune Encephalomyelitis

Reinforcing defective tolerogenic processes slows progression of autoimmune (AI) diseases and has potential to promote drug-free disease remission. Previously, we reported that DNA nanoparticles (DNPs) and cyclic dinucleotides (CDNs) slow progression of experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis, by activating the Stimulator of Interferon Genes (STING) signaling adaptor to stimulate interferon type 1 (IFN-I) production, which induced dendritic cells to express indoleamine 2,3 dioxygenase (IDO) and acquire immune regulatory phenotypes. Here, we show that therapeutic responses to DNPs depend on DNA sensing via cyclic GAMP synthase (cGAS) and interactions between Programmed Death-1 (PD-1) and PD-1 ligands. To investigate how increased tryptophan (Trp) metabolism by IDO promotes therapeutic responses mice were co-treated at EAE onset with DNPs and drugs that inhibit kynurenine aminotransferase-II (KatII) or 3-hydroxyanthranilic acid dioxygenase (HAAO) activity downstream of IDO in the kynurenine (Kyn) pathway. DNP and KatII or HAAO inhibitor co-treatments suppressed EAE progression more effectively than DNPs, while KatII inhibition had no significant therapeutic benefit and HAAO inhibition attenuated but did not prevent EAE progression. Moreover, therapeutic responses to co-treatments were durable as EAE progression did not resume after co-treatment. Thus, using STING agonists to boost IDO activity and manipulating the Kyn pathway downstream of IDO is an effective strategy to enhance tolerogenic responses that overcome autoimmunity to suppress EAE progression.

Immunometabolic Network Interactions of the Kynurenine Pathway in Cutaneous Malignant Melanoma

Dysregulation of the kynurenine pathway has been regarded as a mechanism of tumor immune escape by the enzymatic activity of indoleamine 2, 3 dioxygenase and kynurenine production. However, the immune-modulatory properties of other kynurenine metabolites such as kynurenic acid, 3-hydroxykynurenine, and anthranilic acid are poorly understood. In this study, plasma from patients diagnosed with metastatic cutaneous malignant melanoma (CMM) was obtained before (PRE) and during treatment (TRM) with inhibitors of mitogen-activated protein kinase pathway (MAPKIs). Immuno-oncology related protein profile and kynurenine metabolites were analyzed by proximity extension assay (PEA) and LC/MS-MS, respectively. Correlation network analyses of the data derived from PEA and LC/MS-MS identified a set of proteins that modulate the differentiation of Th1 cells, which is linked to 3-hydroxykynurenine levels. Moreover, MAPKIs treatments are associated with alteration of 3-hydroxykynurenine and 3hydroxyanthranilic acid (3HAA) concentrations and led to higher "CXCL11," and "KLRD1" expression that are involved in T and NK cells activation. These findings imply that the kynurenine pathway is pathologically relevant in patients with CMM.

Pre-, peri- and post-operative factors for the development of pancreatic fistula after pancreatic surgery

BACKGROUND

The most hazardous complication to pancreatic surgery is the development of a post-operative pancreatic fistula (POPF). Appropriate understanding of the underlying pathophysiology, risk factors and perioperative mechanisms may allow for better management and use of preventive measures.

METHODS

Systematic literature search using the English PubMed literature up to April 2019, with emphasis on the past 5 years.

RESULTS

Several risk scores have been developed but none are perfect in predicting POPF risk. A conceptual framework of factors that contribute to the pathophysiology of pancreatic fistulae is still developing but incomplete. Recognized factors include those related to the patient, the pathology and the perioperative care. Interventions such as use of drains, stents and various drugs to mediate risk is still debated. Emerging data suggest that both the microbiome and the inflammation in the post-operative phase may play important roles in risk for POPF. Available risk scores allow for stratification of risk and mitigation strategies tailored to reduce this. However, accurate estimation of risk remains a challenge and mechanisms are only partially understood.

CONCLUSIONS

The pathophysiology of POPF remains poorly understood. Current models only partially explain risks or associated mechanisms. Novel areas of investigation need to be explored for better prediction.

Single-Cell Transcriptomics Uncovers Zonation of Function in the Mesenchyme during Liver Fibrosis

Iterative liver injury results in progressive fibrosis disrupting hepatic architecture, regeneration potential, and liver function. Hepatic stellate cells (HSCs) are a major source of pathological matrix during fibrosis and are thought to be a functionally homogeneous population. Here, we use single-cell RNA sequencing to deconvolve the hepatic mesenchyme in healthy and fibrotic mouse liver, revealing spatial zonation of HSCs across the hepatic lobule. Furthermore, we show that HSCs partition into topographically diametric lobule regions, designated portal vein-associated HSCs (PaHSCs) and central vein-associated HSCs (CaHSCs). Importantly we uncover functional zonation, identifying CaHSCs as the dominant pathogenic collagen-producing cells in a mouse model of centrilobular fibrosis. Finally, we identify LPAR1 as a therapeutic target on collagen-producing CaHSCs, demonstrating that blockade of LPAR1 inhibits liver fibrosis in a rodent NASH model. Taken together, our work illustrates the power of single-cell transcriptomics to resolve the key collagen-producing cells driving liver fibrosis with high precision.

Resolving the fibrotic niche of human liver cirrhosis at single-cell level

Liver cirrhosis is a major cause of death worldwide and is characterized by extensive fibrosis. There are currently no effective antifibrotic therapies available. To obtain a better understanding of the cellular and molecular mechanisms involved in disease pathogenesis and enable the discovery of therapeutic targets, here we profile the transcriptomes of more than 100,000 single human cells, yielding molecular definitions for non-parenchymal cell types that are found in healthy and cirrhotic human liver. We identify a scar-associated TREM2+CD9+ subpopulation of macrophages, which expands in liver fibrosis, differentiates from circulating monocytes and is pro-fibrogenic. We also define ACKR1+ and PLVAP+ endothelial cells that expand in cirrhosis, are topographically restricted to the fibrotic niche and enhance the transmigration of leucocytes. Multi-lineage modelling of ligand and receptor interactions between the scar-associated macrophages, endothelial cells and PDGFRα+ collagen-producing mesenchymal cells reveals intra-scar activity of several pro-fibrogenic pathways including TNFRSF12A, PDGFR and NOTCH signalling. Our work dissects unanticipated aspects of the cellular and molecular basis of human organ fibrosis at a single-cell level, and provides a conceptual framework for the discovery of rational therapeutic targets in liver cirrhosis.

Kynurenine 3-monooxygenase is a critical regulator of renal ischemia-reperfusion injury

Acute kidney injury (AKI) following ischemia–reperfusion injury (IRI) has a high mortality and lacks specific therapies. Here, we report that mice lacking kynurenine 3-monooxygenase (KMO) activity (Kmo^null mice) are protected against AKI after renal IRI. We show that KMO is highly expressed in the kidney and exerts major metabolic control over the biologically active kynurenine metabolites 3-hydroxykynurenine, kynurenic acid, and downstream metabolites. In experimental AKI induced by kidney IRI, Kmo^null mice had preserved renal function, reduced renal tubular cell injury, and fewer infiltrating neutrophils compared with wild-type (Kmo^wt) control mice. Together, these data confirm that flux through KMO contributes to AKI after IRI, and supports the rationale for KMO inhibition as a therapeutic strategy to protect against AKI during critical illness.

Inhibition of a metabolic enzyme linked to inflammation could be a novel treatment approach for sudden kidney failure following a “reperfusion” injury caused by blood flow returning to the organ after a period of insufficient blood supply. Damian Mole and colleagues from the University of Edinburgh, UK, temporarily blocked blood vessels leading to the kidneys of mice to induce organ damage. Mice that lacked a working copy of kynurenine 3-monooxygenase (KMO), a gene that encodes an enzyme involved in metabolizing an essential amino acid linked to immune activation, were protected from injury. These KMO-mutant mice experienced less damage to the kidney’s tubular cells and had fewer pro-inflammatory cells than genetically normal animals. The findings support the idea that blocking KMO and its associated metabolic pathway could help mitigate kidney damage following reperfusion injury in humans.

Survival and new-onset morbidity after critical care admission for acute pancreatitis in Scotland: a national electronic healthcare record linkage cohort study

INTRODUCTION

Severe acute pancreatitis (AP) requiring critical care admission (ccAP) impacts negatively on long-term survival.

OBJECTIVE

To document organ-specific new morbidity and identify risk factors associated with premature mortality after an episode of ccAP.

DESIGN

Cohort study.

SETTING

Electronic healthcare registries in Scotland.

PARTICIPANTS

The ccAP cohort included 1471 patients admitted to critical care with AP between 1 January 2008 and 31 December 2010 followed up until 31 December 2014. The population cohort included 3450 individuals from the general population of Scotland frequency-matched for age, sex and social deprivation.

METHODS

Record linkage of routinely collected electronic health data with population matching.

PRIMARY AND SECONDARY OUTCOME MEASURES

Patient demographics, comorbidity (Charlson Comorbidity Index), acute physiology, organ support and other critical care data were linked to records of mortality (death certificate data) and new-onset morbidity. Kaplan-Meier and Cox regression analyses were used to identify risk factors associated with mortality.

RESULTS

310 patients with AP died during the index admission. Outcomes were not ascertained for five patients, and the deprivation quintile was not known for six patients. 340 of 1150 patients in the resulting postdischarge ccAP cohort died during the follow-up period. Greater comorbidity measured by the Charlson score, prior to ccAP, negatively influenced survival in the hospital and after discharge. The odds of developing new-onset diabetes mellitus after ccAP compared with the general population were 10.70 (95% CI 5.74 to 19.94). A new diagnosis of myocardial infarction, stroke, heart failure, liver disease, peptic ulcer, renal failure, cancer, peripheral vascular disease and lung disease was more frequent in the ccAP cohort than in the general population.

CONCLUSIONS

The persistent deleterious impact of severe AP on long-term outcome and survival is multifactorial in origin, influenced by pre-existing patient characteristics and acute episode features. Further mechanistic and epidemiological investigation is warranted.

Study protocol: HepaT1ca - an observational clinical cohort study to quantify liver health in surgical candidates for liver malignancies

Background

Accurate assessment of liver health prior to undertaking resectional liver surgery or chemoembolisation for primary and secondary cancers is essential for patient safety and optimal outcomes. LiverMultiScan™, an MRI-based technology, non-invasively quantifies hepatic fibroinflammatory disease, steatosis and iron content. We hypothesise that LiverMultiScan™can quantify liver health prior to surgery and inform the risk assessment for patients considering liver surgery or chemoembolization and seek to evaluate this technology in an operational environment.

Methods/Design

HepaT1ca is an observational cohort study in two tertiary-referral liver surgery centres in the United Kingdom. The primary outcome is correlation between the pre-operative liver health assessment score (Hepatica score - calculated by weighting future remnant liver volume by liver inflammation and fibrosis (LIF) score) and the post-operative liver function composite integer-based risk (Hyder-Pawlik) score.

With ethical approval and fully-informed consent, individuals considering liver surgery for primary or secondary cancer will undergo clinical assessment, blood sampling, and LiverMultiScan™multiparametric MRI before and after surgical liver resection or TACE. In nested cohorts of individuals undergoing chemotherapy prior to surgery, or those undergoing portal vein embolization (PVE) as an adjunct to surgery, an additional testing session prior to commencement of treatment will occur. Tissue will be examined histologically and by immunohistochemistry. Pre-operative liver health assessment scores and the post-operative risk scores will be correlated to define the ability of LiverMultiScan™to predict the risk of post-operative morbidity and mortality. Because technology performance in this setting is unknown, a pragmatic sample size will be used. For the primary outcome, n = 200 for the main cohort will allow detection of a minimum correlation coefficient of 0.2 with 5% significance and power of 80%.

Discussion

This study will refine the technology and clinical application of multiparametric MRI (including LiverMultiScan™), to quantify pre-existing liver health and predict post-intervention outcomes following liver resection. If successful, this study will advance the technology and support the use of multiparametric MRI as part of an enhanced pre-operative assessment to improve patient safety and to personalise operative risk assessment of liver surgery/non-surgical intervention.

Trial registration

This study is registered on ClinicalTrials.gov Identifier: NCT03213314.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4737-3) contains supplementary material, which is available to authorized users.

Evaluation of plasma microRNA-122, high-mobility group box 1 and keratin-18 concentrations to stratify acute gallstone disease: a pilot observational cohort study in an emergency general surgery unit

OBJECTIVE

To obtain pilot data to evaluate the discriminatory power of biomarkers microRNA-122 (miR-122), high-mobility group box 1 (HMGB1), full-length keratin-18 (flk-18) and caspase-cleaved keratin-18 (cck-18) in plasma to identify potential biliary complications that may require acute intervention.

DESIGN

An observational biomarker cohort pilot study.

SETTING

In a Scottish University teaching hospital for 12 months beginning on 3 September 2014.

PARTICIPANTS

Blood samples were collected from adults (≥16 years old) referred with acute biliary-type symptoms who have presented to hospital within 24 hours prior were recruited. Patients unable or refused to give informed consent or were transferred from a hospital outside the National Health Service regional trust were excluded.

PRIMARY OUTCOME MEASURES

To evaluate whether circulating miR-122, HMGB1, flk-18 and cck-18 can discriminate between people with and without gallstone disease and uncomplicated from complicated gallstone disease during the first 24 hours of hospital admission.

RESULTS

300 patients were screened of which 285 patients were included. Plasma miR-122, cck-18 and flk-18 concentrations were increased in patients with gallstones compared with those without (miR-122: median: 2.89×104 copies/mL vs 0.90×104 copies/mL (p<0.001); cck-18: 121.2 U/L vs 103.5 U/L (p=0.031); flk-18: 252.4 U/L vs 145.1 U/L (p<0.001)). Uncomplicated gallstone disease was associated with higher miR-122 and cck-18 concentrations than complicated disease (miR-122: 5.72×104 copies/mL vs 2.26×104 copies/mL (p=0.023); cck-18: 139.7 U/L vs 113.6 U/L (p=0.047)). There was no significant difference in HMGB1 concentration between patients with and without gallstones (p=0.559). Separation between groups for all biomarkers was modest.

CONCLUSION

miR-122 and keratin-18 plasma concentrations are elevated in patients with gallstones. However, this result is confounded by the association between biomarker concentrations, age and gender. In this pilot study, miR-122 and keratin-18 were not sufficiently discriminatory to be progressed as clinically useful biomarkers in this context.

Diclofenac Identified as a Kynurenine 3-Monooxygenase Binder and Inhibitor by Molecular Similarity Techniques

In this study, we apply a battery of molecular similarity techniques to known inhibitors of kynurenine 3-monooxygenase (KMO), querying each against a repository of approved, experimental, nutraceutical, and illicit drugs. Four compounds are assayed against KMO. Subsequently, diclofenac (also known by the trade names Voltaren, Voltarol, Aclonac, and Cataflam) has been confirmed as a human KMO protein binder and inhibitor in cell lysate with low micromolar K_D and IC₅₀, respectively, and low millimolar cellular IC₅₀. Hit to drug hopping, as exemplified here for one of the most successful anti-inflammatory medicines ever invented, holds great promise for expansion into new disease areas and highlights the not-yet-fully-exploited potential of drug repurposing.

ABCC1 confers tissue-specific sensitivity to cortisol versus corticosterone: A rationale for safer glucocorticoid replacement therapy

The aim of treatment in congenital adrenal hyperplasia is to suppress excess adrenal androgens while achieving physiological glucocorticoid replacement. However, current glucocorticoid replacement regimes are inadequate because doses sufficient to suppress excess androgens almost invariably induce adverse metabolic effects. Although both cortisol and corticosterone are glucocorticoids that circulate in human plasma, any physiological role for corticosterone has been neglected. In the brain, the adenosine 5'-triphosphate-binding cassette transporter ABCB1 exports cortisol but not corticosterone. Conversely, ABCC1 exports corticosterone but not cortisol. We show that ABCC1, but not ABCB1, is expressed in human adipose and that ABCC1 inhibition increases intracellular corticosterone, but not cortisol, and induces glucocorticoid-responsive gene transcription in human adipocytes. Both C57Bl/6 mice treated with the ABCC1 inhibitor probenecid and FVB mice with deletion of Abcc1 accumulated more corticosterone than cortisol in adipose after adrenalectomy and corticosteroid infusion. This accumulation was sufficient to increase glucocorticoid-responsive adipose transcript expression. In human adipose tissue, tissue corticosterone concentrations were consistently low, and ABCC1 mRNA was up-regulated in obesity. To test the hypothesis that corticosterone effectively suppresses adrenocorticotropic hormone (ACTH) without the metabolic adverse effects of cortisol, we infused cortisol or corticosterone in patients with Addison's disease. ACTH suppression was similar, but subcutaneous adipose transcripts of glucocorticoid-responsive genes were higher after infusion with cortisol rather than with corticosterone. These data indicate that corticosterone may be a metabolically favorable alternative to cortisol for glucocorticoid replacement therapy when ACTH suppression is desirable, as in congenital adrenal hyperplasia, and justify development of a pharmaceutical preparation.

Detecting drug-target binding in cells using fluorescence-activated cell sorting coupled with mass spectrometry analysis

The assessment of drug-target engagement for determining the efficacy of a compound inside cells remains challenging, particularly for difficult target proteins. Existing techniques are more suited to soluble protein targets. Difficult target proteins include those with challenging in vitro solubility, stability or purification properties that preclude target isolation. Here, we report a novel technique that measures intracellular compound-target complex formation, as well as cellular permeability, specificity and cytotoxicity-the toxicity-affinity-permeability-selectivity (TAPS) technique. The TAPS assay is exemplified here using human kynurenine 3-monooxygenase (KMO), a challenging intracellular membrane protein target of significant current interest. TAPS confirmed target binding of known KMO inhibitors inside cells. We conclude that the TAPS assay can be used to facilitate intracellular hit validation on most, if not all intracellular drug targets.

Structural and mechanistic basis of differentiated inhibitors of the acute pancreatitis target kynurenine-3-monooxygenase

Kynurenine-3-monooxygenase (KMO) is a key FAD-dependent enzyme of tryptophan metabolism. In animal models, KMO inhibition has shown benefit in neurodegenerative diseases such as Huntington's and Alzheimer's. Most recently it has been identified as a target for acute pancreatitis multiple organ dysfunction syndrome (AP-MODS); a devastating inflammatory condition with a mortality rate in excess of 20%. Here we report and dissect the molecular mechanism of action of three classes of KMO inhibitors with differentiated binding modes and kinetics. Two novel inhibitor classes trap the catalytic flavin in a previously unobserved tilting conformation. This correlates with picomolar affinities, increased residence times and an absence of the peroxide production seen with previous substrate site inhibitors. These structural and mechanistic insights culminated in GSK065(C1) and GSK366(C2), molecules suitable for preclinical evaluation. Moreover, revising the repertoire of flavin dynamics in this enzyme class offers exciting new opportunities for inhibitor design.

Kynurenine-3-monooxygenase (KMO) is an emerging clinical target for treatment of neurodegenerative diseases and acute pancreatitis. Here, the authors report potent inhibitors that bind KMO in an unexpected conformation, offering structural and mechanistic insights for future drug discovery ventures.

Acute physiological effects of glucocorticoids on fuel metabolism in humans are permissive but not direct

BACKGROUND AND AIMS

The effects of glucocorticoids on fuel metabolism are complex. Acute glucocorticoid excess promotes lipolysis but chronic glucocorticoid excess causes visceral fat accumulation. We hypothesized that interactions between cortisol and insulin and adrenaline account for these conflicting results. We tested the effect of cortisol on lipolysis and glucose production with and without insulin and adrenaline in humans both in vivo and in vitro.

MATERIALS AND METHODS

A total of 20 healthy men were randomized to low and high insulin groups (both n = 10). Subjects attended on 3 occasions and received low (c. 150 nM), medium (c. 400 nM) or high (c. 1400 nM) cortisol infusion in a randomized crossover design. Deuterated glucose and glycerol were infused intravenously along with a pancreatic clamp (somatostatin with replacement of glucagon, insulin and growth hormone) and adrenaline. Subcutaneous adipose tissue was obtained for analysis. In parallel, the effect of cortisol on lipolysis was tested in paired primary cultures of human subcutaneous and visceral adipocytes.

RESULTS

In vivo, high cortisol increased lipolysis only in the presence of high insulin and/or adrenaline but did not alter glucose kinetics. High cortisol increased adipose mRNA levels of ATGL, HSL and CGI-58 and suppressed G0S2. In vitro, high cortisol increased lipolysis in the presence of insulin in subcutaneous, but not visceral, adipocytes.

CONCLUSIONS

The acute lipolytic effects of cortisol require supraphysiological concentrations, are dependent on insulin and adrenaline and are observed only in subcutaneous adipose tissue. The resistance of visceral adipose tissue to cortisol's lipolytic effects may contribute to the central fat accumulation observed with chronic glucocorticoid excess.

Development of a Series of Kynurenine 3-Monooxygenase Inhibitors Leading to a Clinical Candidate for the Treatment of Acute Pancreatitis

Recently, we reported a novel role for KMO in the pathogenesis of acute pancreatitis (AP). A number of inhibitors of kynurenine 3-monooxygenase (KMO) have previously been described as potential treatments for neurodegenerative conditions and particularly for Huntington's disease. However, the inhibitors reported to date have insufficient aqueous solubility relative to their cellular potency to be compatible with the intravenous (iv) dosing route required in AP. We have identified and optimized a novel series of high affinity KMO inhibitors with favorable physicochemical properties. The leading example is exquisitely selective, has low clearance in two species, prevents lung and kidney damage in a rat model of acute pancreatitis, and is progressing into preclinical development.

The discovery of potent and selective kynurenine 3-monooxygenase inhibitors for the treatment of acute pancreatitis

A series of potent, competitive and highly selective kynurenine monooxygenase inhibitors have been discovered via a substrate-based approach for the treatment of acute pancreatitis. The lead compound demonstrated good cellular potency and clear pharmacodynamic activity in vivo.

Emergency general surgery 'Hot Clinics' reduce admission rates and duration of inpatient stay

OBJECTIVE

To determine the impact of a 'Hot Clinic' (HC) on emergency general surgery patient flow-through.

DESIGN

Prospective service evaluation study.

SETTING

HC is a four-bedded area coordinated by a specialist nurse. The HC consultant sees emergency patients referred from the emergency department, general practitioners or those in preceding 24 h considered suitable for interim discharge while awaiting investigations and HC reassessment.

PATIENTS

All patients with acute abdominal pain were evaluated in three 4 week groups: before (group 1), 1 month (group 2) and 6 months after the HC was introduced (group 3). Interhospital transfers, intrahospital ward referrals and trauma patients were excluded.

INTERVENTION

Introduction of consultant-led surgical HC every weekday afternoon.

MAIN OUTCOME MEASURES

Proportion of patients admitted under general surgeons, length of inpatient stay and the proportion of patients referred again within 3 months were investigated.

RESULTS

1409 patients were referred, of which 1061 met the inclusion criteria: 307 in group 1, 326 in group 2 and 428 in group 3. There was no difference in gender distribution (p=0.759). Inpatient admissions were significantly reduced (85.0% vs 78.2% vs 54.4%; p<0.001) and the inpatient duration of stay was significantly shorter after HC introduction (median (IQR) (95% CI) 63.8 (29.0-111.6) (51.8 to 72.8) hours vs 48.8 (21.7-101.2) (42.0 to 55.6) hours vs 47.7 (20.9-92.7) (42.8 to 56.9) hours; p=0.011).

CONCLUSIONS

Emergency general surgery HCs are associated with significant reductions in admission rates and inpatient bed occupancy. This service redesign has the potential to dramatically relieve pressure on acute surgical services.

Increased levels of 3-hydroxykynurenine parallel disease severity in human acute pancreatitis

Inhibition of kynurenine 3-monooxygenase (KMO) protects against multiple organ dysfunction (MODS) in experimental acute pancreatitis (AP). We aimed to precisely define the kynurenine pathway activation in relation to AP and AP-MODS in humans, by carrying out a prospective observational study of all persons presenting with a potential diagnosis of AP for 90 days. We sampled peripheral venous blood at 0, 3, 6, 12, 24, 48, 72 and 168 hours post-recruitment. We measured tryptophan metabolite concentrations and analysed these in the context of clinical data and disease severity indices, cytokine profiles and C-reactive protein (CRP) concentrations. 79 individuals were recruited (median age: 59.6 years; 47 males, 59.5%). 57 met the revised Atlanta definition of AP: 25 had mild, 23 moderate, and 9 severe AP. Plasma 3-hydroxykynurenine concentrations correlated with contemporaneous APACHE II scores (R² = 0.273; Spearman rho = 0.581; P < 0.001) and CRP (R² = 0.132; Spearman rho = 0.455, P < 0.001). Temporal profiling showed early tryptophan depletion and contemporaneous 3-hydroxykynurenine elevation. Furthermore, plasma concentrations of 3-hydroxykynurenine paralleled systemic inflammation and AP severity. These findings support the rationale for investigating early intervention with a KMO inhibitor, with the aim of reducing the incidence and severity of AP-associated organ dysfunction.

Identifying risk factors for progression to critical care admission and death among individuals with acute pancreatitis: a record linkage analysis of Scottish healthcare databases

OBJECTIVES

Acute pancreatitis (AP) can initiate systemic complications that require support in critical care (CC). Our objective was to use the unified national health record to define the epidemiology of AP in Scotland, with a specific focus on deterministic and prognostic factors for CC admission in AP.

SETTING

Health boards in Scotland (n=4).

PARTICIPANTS

We included all individuals in a retrospective observational cohort with at least one episode of AP (ICD10 code K85) occurring in Scotland from 1 April 2009 to 31 March 2012. 3340 individuals were coded as AP.

METHODS

Data from 16 sources, spanning general practice, community prescribing, Accident and Emergency attendances, hospital in-patient, CC and mortality registries, were linked by a unique patient identifier in a national safe haven. Logistic regression and gamma models were used to define independent predictive factors for severe AP (sAP) requiring CC admission or leading to death.

RESULTS

2053 individuals (61.5% (95% CI 59.8% to 63.2%)) met the definition for true AP (tAP). 368 patients (17.9% of tAP (95% CI 16.2% to 19.6%)) were admitted to CC. Predictors of sAP were pre-existing angina or hypertension, hypocalcaemia and age 30-39 years, if type 2 diabetes mellitus was present. The risk of sAP was lower in patients with multiple previous episodes of AP. In-hospital mortality in tAP was 5.0% (95% CI 4.1% to 5.9%) overall and 21.7% (95% CI 19.9% to 23.5%) in those with tAP necessitating CC admission.

CONCLUSIONS

National record-linkage analysis of routinely collected data constitutes a powerful resource to model CC admission and prognosticate death during AP. Mortality in patients with AP who require CC admission remains high.

Prostaglandin E₂ constrains systemic inflammation through an innate lymphoid cell-IL-22 axis

Systemic inflammation, which results from the massive release of proinflammatory molecules into the circulatory system, is a major risk factor for severe illness, but the precise mechanisms underlying its control are not fully understood. We observed that prostaglandin E2 (PGE2), through its receptor EP4, is down-regulated in human systemic inflammatory disease. Mice with reduced PGE2 synthesis develop systemic inflammation, associated with translocation of gut bacteria, which can be prevented by treatment with EP4 agonists. Mechanistically, we demonstrate that PGE2-EP4 signaling acts directly on type 3 innate lymphoid cells (ILCs), promoting their homeostasis and driving them to produce interleukin-22 (IL-22). Disruption of the ILC-IL-22 axis impairs PGE2-mediated inhibition of systemic inflammation. Hence, the ILC-IL-22 axis is essential in protecting against gut barrier dysfunction, enabling PGE2-EP4 signaling to impede systemic inflammation.

Lung ultrasonography as a direct measure of evolving respiratory dysfunction and disease severity in patients with acute pancreatitis

BACKGROUND

The value of lung ultrasonography in the diagnosis of respiratory dysfunction and severity stratification in patients with acute pancreatitis (AP) was investigated.

METHODS

Over a 3-month period, 41 patients (median age: 59.1 years; 21 males) presenting with a diagnosis of potential AP were prospectively recruited. Each participant underwent lung ultrasonography and the number of comet tails was linked with contemporaneous clinical data. Group comparisons, areas under the curve (AUC) and respective measures of diagnostic accuracy were investigated.

RESULTS

A greater number of comet tails were evident in patients with respiratory dysfunction (P = 0.021), those with severe disease (P < 0.001) and when contemporaneous and maximum CRP exceeded 100 mg/L (P = 0.048 and P = 0.003 respectively). Receiver-operator characteristic plot area under the curve (AUC) was greater when examining upper lung quadrants, using respiratory dysfunction and AP severity as variables of interest (AUC = 0.783, 95% C.I.: 0.544-0.962, and AUC = 0.996, 95% C.I.: 0.982-1.000, respectively). Examining all lung quadrants except for the lower lateral resulted in greater AUCs for contemporaneous and maximum CRP (AUC = 0.708, 95% C.I.: 0.510-0.883, and AUC = 0.800, 95% C.I.: 0.640-0.929).

DISCUSSION

Ultrasonography of non-dependent lung parenchyma can reliably detect evolving respiratory dysfunction in AP. This simple bedside technique shows promise as an adjunct to severity stratification.

Kynurenine-3-monooxygenase inhibition prevents multiple organ failure in rodent models of acute pancreatitis

Acute pancreatitis (AP) is a common and devastating inflammatory condition of the pancreas that is considered to be a paradigm of sterile inflammation leading to systemic multiple organ dysfunction syndrome (MODS) and death. Acute mortality from AP-MODS exceeds 20% (ref. 3), and the lifespans of those who survive the initial episode are typically shorter than those of the general population. There are no specific therapies available to protect individuals from AP-MODS. Here we show that kynurenine-3-monooxygenase (KMO), a key enzyme of tryptophan metabolism, is central to the pathogenesis of AP-MODS. We created a mouse strain that is deficient for Kmo (encoding KMO) and that has a robust biochemical phenotype that protects against extrapancreatic tissue injury to the lung, kidney and liver in experimental AP-MODS. A medicinal chemistry strategy based on modifications of the kynurenine substrate led to the discovery of the oxazolidinone GSK180 as a potent and specific inhibitor of KMO. The binding mode of the inhibitor in the active site was confirmed by X-ray co-crystallography at 3.2 Å resolution. Treatment with GSK180 resulted in rapid changes in the levels of kynurenine pathway metabolites in vivo, and it afforded therapeutic protection against MODS in a rat model of AP. Our findings establish KMO inhibition as a novel therapeutic strategy in the treatment of AP-MODS, and they open up a new area for drug discovery in critical illness.

Lung ultrasonography as a direct measure of evolving respiratory dysfunction and disease severity in patients with acute pancreatitis

BACKGROUND

The value of lung ultrasonography in the diagnosis of respiratory dysfunction and severity stratification in patients with acute pancreatitis (AP) was investigated.

METHODS

Over a 3-month period, 41 patients (median age: 59.1 years; 21 males) presenting with a diagnosis of potential AP were prospectively recruited. Each participant underwent lung ultrasonography, and the number of comet tails present on scans was linked with contemporaneous clinical data. Group comparisons, areas under the curve (AUC) and respective measures of diagnostic accuracy were investigated.

RESULTS

A greater number of comet tails were evident in patients with respiratory dysfunction (P = 0.013), those with severe disease (P = 0.001) and when contemporaneous and maximum in-patient C-reactive protein (CRP) exceeded 150 mg/l (P = 0.018 and P = 0.049, respectively). Receiver-operator characteristic plot area under the curve (AUC) was greater when examining upper lung quadrants, using respiratory dysfunction and AP severity as variables of interest (AUC = 0.803, 95% CI: 0.583-1.000, and AUC = 0.996, 95% CI: 0.983-1.000, respectively). Examining all lung quadrants resulted in greater AUCs for contemporaneous and maximum CRP (AUC = 0.764, 95% CI: 0.555-0.972, and AUC = 0.704, 95% CI: 0.510-0.898).

DISCUSSION

Ultrasonography of non-dependent lung parenchyma can reliably detect evolving respiratory dysfunction in AP. This simple bedside technique shows promise as an adjunct to severity stratification.

A magnetic bead-based ligand binding assay to facilitate human kynurenine 3-monooxygenase drug discovery

Human kynurenine 3-monooxygenase (KMO) is emerging as an important drug target enzyme in a number of inflammatory and neurodegenerative disease states. Recombinant protein production of KMO, and therefore discovery of KMO ligands, is challenging due to a large membrane targeting domain at the C-terminus of the enzyme that causes stability, solubility, and purification difficulties. The purpose of our investigation was to develop a suitable screening method for targeting human KMO and other similarly challenging drug targets. Here, we report the development of a magnetic bead-based binding assay using mass spectrometry detection for human KMO protein. The assay incorporates isolation of FLAG-tagged KMO enzyme on protein A magnetic beads. The protein-bound beads are incubated with potential binding compounds before specific cleavage of the protein-compound complexes from the beads. Mass spectrometry analysis is used to identify the compounds that demonstrate specific binding affinity for the target protein. The technique was validated using known inhibitors of KMO. This assay is a robust alternative to traditional ligand-binding assays for challenging protein targets, and it overcomes specific difficulties associated with isolating human KMO.

Early organ dysfunction affects long-term survival in acute pancreatitis patients

BACKGROUND

The effect of early organ dysfunction on long-term survival in acute pancreatitis (AP) patients is unknown.

OBJECTIVE

The aim of this study was to ascertain whether early organ dysfunction impacts on long-term survival after an episode of AP.

METHODS

A retrospective analysis was performed using survival data sourced from a prospectively maintained database of patients with AP admitted to the Royal Infirmary of Edinburgh during a 5-year period commencing January 2000. A multiple organ dysfunction syndrome (MODS) score of ≥ 2 during the first week of admission was used to define early organ dysfunction. After accounting for in-hospital deaths, long-term survival probabilities were estimated using the Kaplan-Meier test. The prognostic significance of patient characteristics was assessed by univariate and multivariate analyses using Cox's proportional hazards methods.

RESULTS

A total of 694 patients were studied (median follow-up: 8.8 years). Patients with early organ dysfunction (MODS group) were found to have died prematurely [mean survival: 10.0 years, 95% confidence interval (CI) 9.4-10.6 years] in comparison with the non-MODS group (mean survival: 11.6 years, 95% CI 11.2-11.9 years) (log-rank test, P = 0.001) after the exclusion of in-hospital deaths. Multivariate analysis confirmed MODS as an independent predictor of long-term survival [hazard ratio (HR): 1.528, 95% CI 1.72-2.176; P = 0.019] along with age (HR: 1.062; P < 0.001), alcohol-related aetiology (HR: 2.027; P = 0.001) and idiopathic aetiology (HR: 1.548; P = 0.048).

CONCLUSIONS

Early organ dysfunction in AP is an independent predictor of long-term survival even when in-hospital deaths are accounted for. Negative predictors also include age, and idiopathic and alcohol-related aetiologies.

Relaxin modulates human and rat hepatic myofibroblast function and ameliorates portal hypertension in vivo

Active myofibroblast (MF) contraction contributes significantly to the increased intrahepatic vascular resistance that is the primary cause of portal hypertension (PHT) in cirrhosis. We sought proof of concept for direct therapeutic targeting of the dynamic component of PHT and markers of MF activation using short-term administration of the peptide hormone relaxin (RLN). We defined the portal hypotensive effect in rat models of sinusoidal PHT and the expression, activity, and function of the RLN-receptor signaling axis in human liver MFs. The effects of RLN were studied after 8 and 16 weeks carbon tetrachloride intoxication, following bile duct ligation, and in tissue culture models. Hemodynamic changes were analyzed by direct cannulation, perivascular flowprobe, indocyanine green imaging, and functional magnetic resonance imaging. Serum and hepatic nitric oxide (NO) levels were determined by immunoassay. Hepatic inflammation was assessed by histology and serum markers and fibrosis by collagen proportionate area. Gene expression was analyzed by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and western blotting and hepatic stellate cell (HSC)-MF contractility by gel contraction assay. Increased expression of RLN receptor (RXFP1) was shown in HSC-MFs and fibrotic liver diseases in both rats and humans. RLN induced a selective and significant reduction in portal pressure in pathologically distinct PHT models, through augmentation of intrahepatic NO signaling and a dramatic reduction in contractile filament expression in HSC-MFs. Critical for translation, RLN did not induce systemic hypotension even in advanced cirrhosis models. Portal blood flow and hepatic oxygenation were increased by RLN in early cirrhosis. Treatment of human HSC-MFs with RLN inhibited contractility and induced an antifibrogenic phenotype in an RXFP1-dependent manner.

CONCLUSION

We identified RXFP1 as a potential new therapeutic target for PHT and MF activation status.

Lead discovery for human kynurenine 3-monooxygenase by high-throughput RapidFire mass spectrometry

Kynurenine 3-monooxygenase (KMO) is a therapeutically important target on the eukaryotic tryptophan catabolic pathway, where it converts L-kynurenine (Kyn) to 3-hydroxykynurenine (3-HK). We have cloned and expressed the human form of this membrane protein as a full-length GST-fusion in a recombinant baculovirus expression system. An enriched membrane preparation was used for a directed screen of approximately 78,000 compounds using a RapidFire mass spectrometry (RF-MS) assay. The RapidFire platform provides an automated solid-phase extraction system that gives a throughput of approximately 7 s per well to the mass spectrometer, where direct measurement of both the substrate and product allowed substrate conversion to be determined. The RF-MS methodology is insensitive to assay interference, other than where compounds have the same nominal mass as Kyn or 3-HK and produce the same mass transition on fragmentation. These instances could be identified by comparison with the product-only data. The screen ran with excellent performance (average Z' value 0.8) and provided several tractable hit series for further investigation.

Bacterial expression of human kynurenine 3-monooxygenase: solubility, activity, purification

•

This is the first report of soluble and active bacterially expressed human KMO protein.

•

Partial purification of the enzyme was achieved and the two protein co-elutants identified.

•

Steady state kinetic parameters were comparable to those reported for mammalian expressed.

•

The C-terminal membrane targetting domain of human KMO is required for its enzymatic activity.

Kynurenine 3-monooxygenase (KMO) is an enzyme central to the kynurenine pathway of tryptophan metabolism. KMO has been implicated as a therapeutic target in several disease states, including Huntington’s disease. Recombinant human KMO protein production is challenging due to the presence of transmembrane domains, which localise KMO to the outer mitochondrial membrane and render KMO insoluble in many in vitro expression systems. Efficient bacterial expression of human KMO would accelerate drug development of KMO inhibitors but until now this has not been achieved. Here we report the first successful bacterial (Escherichia coli) expression of active FLAG™-tagged human KMO enzyme expressed in the soluble fraction and progress towards its purification.

Expression of osteopontin coregulators in primary colorectal cancer and associated liver metastases

BACKGROUND

A transcription regulatory complex (TRC) that includes Ets1, Ets2, PEA3 and β-catenin/T-cell factors regulates osteopontin (OPN) that is implicated in colorectal cancer (CRC) dissemination. The consistency of OPN transcriptional control between primary CRC and metastases is unclear. This study investigates expression and prognostic significance of the OPN-TRC in primary human CRC and associated colorectal liver metastases (CRLM).

METHODS

Osteopontin-TRC factors were assayed by digital microscopy in 38 primary CRCs and matched CRLM specimens and assessed against clinical prognosis.

RESULTS

In primary CRC, OPN expression intensity correlated with that of its co-activators, PEA3 (r=0.600; P<0.01), Ets1 (r=0.552; P<0.01), Ets2 (r=0.521; P<0.01) and had prognostic significance. Osteopontin intensity in primary CRC inversely correlated with the interval between diagnosis and resection of CRLM. Overall OPN intensity was lower in CRLM than primary CRC and correlations with co-activators were weaker, for example, Ets1 (P=0.047), PEA3 (P=0.022) or nonsignificant (Ets2). The ratio of OPN expression in CRLM vs primary CRC had prognostic significance.

CONCLUSION

This study supports transcriptional control of OPN by known coregulators in both primary and secondary CRC. Weaker associations in CRLM suggest involvement of other unknown factors possibly from the liver microenvironment or resulting from additional genetic or epigenetic changes that drive tumour metastatic capability in OPN transcriptional control.

Detailed fluid resuscitation profiles in patients with severe acute pancreatitis

BACKGROUND AND AIM

Appropriate and timely initial fluid resuscitation in acute pancreatitis (AP) is critical. The aim of this retrospective study was to evaluate fluid therapy on an hour-by-hour basis in relation to standard indices of adequate resuscitation during AP.

METHODS

Emergency room shock charts, fluid balance sheets and intensive care (ICU) charts for all patients with AP admitted to ICU in a large acute hospital were examined. Vital signs, clinical course and fluid administered during the first 72 h after admission were tabulated against urine output, central venous pressure (CVP) and inotrope/vasopressor therapy.

RESULTS

Sixty-three consecutive patients with AP were initially evaluated. Inter-hospital transfers with established organ dysfunction (n= 11) or where records had insufficient detail (n= 22) were excluded. In the remaining 30 patients, in-hospital death occurred in 7. The cumulative volume of crystalloid given was significantly less at 48 h in patients who died in hospital (3331 ± 800 ml vs. survivors, 7287 ± 544 ml; P < 0.001). Non-survivors had a higher CVP, and received more inotropes/vasopressors.

CONCLUSION

  In severe AP-associated organ failure, fluid resuscitation profiles differ between survivors and non-survivors. CVP alone as a crude indicator of adequate resuscitation may be unreliable, potentially leading to the use of inotropes/vasopressors in the inadequately filled patient.

Discrepancy between the extent of pancreatic necrosis and multiple organ failure score in severe acute pancreatitis

BACKGROUND

Whether pancreatic necrosis is a prerequisite for the development of multiorgan failure (MOF) in severe acute pancreatitis (AP) is not clear and has implications for the rational design of translational therapies. This study was designed to investigate the magnitude of any association between MOF and radiologically evident pancreatic or extrapancreatic complications of AP.

METHODS

Data regarding 276 patients with AP were analyzed retrospectively with regard to clinical presentation, MOF severity, computerized tomography (CT) evidence of pancreatic necrosis, and modified CT severity index (MCTSI).

RESULTS

Agreement between the presence of necrosis and MOF status was seen in 160 of 276 patient episodes (58%; 95% confidence intervals (CI), 52.1-63.8%). In 116 of 276 episodes, the MCTSI and MOF scores disagreed (42%; 95% CI, 36.2-47.9%). CT evidence of pancreatic necrosis was present in 21 of 104 (20.2%) patients without any evidence of MOF, and there was no evidence of necrosis on CT scan in 95 of 176 (54%) patients with MOF. Full-factorial univariate analysis suggested that extrapancreatic complications seen on CT, in particular intra-abdominal fluid collections (effect size = 0.02; P = 0.016) and abnormal liver enhancement (effect size = 0.035; P = 0.031) were associated with severity of MOF, and exerted an even greater effect when they occurred synchronously.

CONCLUSIONS

The discrepancy between the presence of necrosis and the occurrence of MOF favors association but not cause in AP. A complex, systems-based, pleiotropic inflammatory network with a common root, in which the extent of pancreatic necrosis influences the severity of MOF in certain individuals and MOF exacerbates the development of pancreatic necrosis in others, seems more likely.

Management of liver trauma

BACKGROUND

Blunt and penetrating liver trauma is common and often presents major diagnostic and management problems.

METHODS

A literature review was undertaken to determine the current consensus on investigation and management strategies.

RESULTS

The liver is the most frequently injured organ following abdominal trauma. Immediate assessment with ultrasound has replaced diagnostic peritoneal lavage in the resuscitation room, but computerised tomography remains the gold standard investigation. Nonoperative management is preferred in stable patients but laparotomy is indicated in unstable patients. Damage control techniques such as perihepatic packing, hepatotomy plus direct suture, and resectional debridement are recommended. Major complex surgical procedures such as anatomical resection or atriocaval shunting are now thought to be redundant in the emergency setting. Packing is also recommended for the inexperienced surgeon to allow control and stabilisation prior to transfer to a tertiary centre. Interventional radiological techniques are becoming more widely used, particularly in patients who are being managed nonoperatively or have been stabilised by perihepatic packing.

CONCLUSIONS

Management of liver injuries has evolved significantly throughout the last two decades. In the absence of other abdominal injuries, operative management can usually be avoided. Patients with more complex injuries or subsequent complications should be transferred to a specialist centre to optimise final outcome.

Management of liver trauma

BACKGROUND

Blunt and penetrating liver trauma is common and often presents major diagnostic and management problems.

METHODS

A literature review was undertaken to determine the current consensus on investigation and management strategies.

RESULTS

The liver is the most frequently injured organ following abdominal trauma. Immediate assessment with ultrasound has replaced diagnostic peritoneal lavage in the resuscitation room, but computerised tomography remains the gold standard investigation. Nonoperative management is preferred in stable patients but laparotomy is indicated in unstable patients. Damage control techniques such as perihepatic packing, hepatotomy plus direct suture, and resectional debridement are recommended. Major complex surgical procedures such as anatomical resection or atriocaval shunting are now thought to be redundant in the emergency setting. Packing is also recommended for the inexperienced surgeon to allow control and stabilisation prior to transfer to a tertiary centre. Interventional radiological techniques are becoming more widely used, particularly in patients who are being managed nonoperatively or have been stabilised by perihepatic packing.

CONCLUSIONS

Management of liver injuries has evolved significantly throughout the last two decades. In the absence of other abdominal injuries, operative management can usually be avoided. Patients with more complex injuries or subsequent complications should be transferred to a specialist centre to optimise final outcome.

Incidence of individual organ dysfunction in fatal acute pancreatitis: analysis of 1024 death records

BACKGROUND

Extrapancreatic organ dysfunction is the key determinant of mortality in acute pancreatitis (AP). This study aimed to document the frequency and duration of individual organ dysfunction in all fatalities caused by AP in a large, population-based cohort.

METHODS

All deaths caused by AP in Scotland between 2000 and 2006 inclusive were analysed (n = 1024).

RESULTS

The median time lapse between the onset of AP and death was 6 days (interquartile range [IQR] 17 days); that between the onset of organ dysfunction and death was 3 days (IQR 7 days). There was no apparent bimodal distribution. The majority of patients had single- (384 patients) or two-system (242 patients) extrapancreatic organ dysfunction. Pulmonary dysfunction was most prevalent (30% of organ-specific entries, 198/660), followed by cardiovascular (18%, 117/660), renal (16%, 108/660), liver (11%, 71/660), gastrointestinal (9%, 59/660), haemorrhage (6%, 38/660), coagulopathy (5%, 31/660) and central nervous system (6%, 38/660) dysfunction.

CONCLUSIONS

Death in AP occurs early in the disease course. The present findings support the primacy of pulmonary injury as the modal pattern of organ dysfunction in severe AP, with increased frequencies of cardiovascular and renal compromise in fatal AP.

Differential preservation of lipopolysaccharide-induced chemokine/cytokine expression during experimental pancreatitis-associated organ failure in rats shows a regulatory expressed phenotype

BACKGROUND

Altered lipopolysaccharide (LPS)-responsiveness is a key feature of acute pancreatitis (AP)-associated multiple organ failure (AP-MOF) in rats and humans.

AIM

To determine the differential expression of 16 cytokines and chemokines in response to delayed LPS administration in established experimental AP-MOF in rats.

METHODS

In a cubic factorial group design (12 groups, n = 6 rats/group), 0, 6 and 30 microg/kg Escherichia coli 0111:B4 LPS was administered intra-arterially, 18 h into experimental AP-MOF or sham laparotomy. AP was induced by intraductal glycodeoxycholic acid and intravenous caerulein. Central venous serum concentrations of 16 cytokines and chemokines were measured by Searchlight multiplex ELISA.

RESULTS

Four patterns were observed: (1) TNF-alpha, IL-1alpha, IL-1beta, IL-6, IFN-gamma, MCP-1, MIP-2alpha, MIP-3alpha, fractalkine and RANTES showed a diminished LPS response in AP versus sham (p < 0.001, ANOVA); (2) IL-2, IL-4 and GM-CSF levels were undetectable; (3) CINC-2alpha and GRO/KC showed little or no difference between AP and controls, and (4) IL-10 concentrations after 0 and 6 microg/kg, but not 30 microg/kg LPS injection were significantly higher in AP than controls (p < 0.001, ANOVA).

CONCLUSION

Experimental AP-MOF in rats results in differential preservation of the cytokine and chemokine response to LPS challenge, with a predominantly regulatory expressed phenotype.

Tryptophan catabolites in mesenteric lymph may contribute to pancreatitis-associated organ failure

Background

Multiple organ failure (MOF) is the key determinant of mortality in acute pancreatitis (AP). Mesenteric lymph cytotoxicity contributes to organ failure in experimental models of systemic inflammation. The aim of this study was to evaluate the mesenteric lymph pathway and the lymph injury proteome in experimental AP-associated MOF, and to test the hypothesis that immunoregulatory tryptophan catabolites contribute to mesenteric lymph cytotoxicity.

Methods

Using an experimental model of AP in rats, the humoral component of mesenteric lymph in AP was compared with that from sham-operated control animals, using in vitro and in vivo cytotoxicity assays, high-throughput proteomics and high-performance liquid chromatography. The experimental findings were corroborated in a cohort of 34 patients with AP.

Results

Compared with biologically inactive lymph from sham-operated rats, mesenteric lymph in AP became cytotoxic 3 h after induction. Hierarchical clustering of lymph proteomic mass spectra predicted the biological behaviour of lymph. Levels of the immunoregulatory tryptophan catabolite, 3-hydroxykynurenine, were increased in cytotoxic lymph and re-created cytotoxicity in vitro. In humans with AP, plasma kynurenine concentrations correlated in real time with MOF scores and preceded a requirement for mechanical ventilation and haemodialysis.

Conclusion

These results support the concept that mesenteric lymph-borne kynurenines may contribute to pancreatitis-associated MOF.

Electronic patient data confidentiality practices among surgical trainees: questionnaire study

INTRODUCTION

The objective of this work was to evaluate the safeguards implemented by surgical trainees to protect the confidentiality of electronic patient data through a structured questionnaire sent to Northern Ireland surgical trainees.

PARTICIPANTS AND METHODS

A group of 32 basic and higher surgical trainees attending a meeting of the Northern Ireland Association of Surgeons-in-Training were invited to complete a questionnaire regarding their computer use, UK Data Protection Act, 1988 registration and electronic data confidentiality practices.

RESULTS

Of these 32 trainees, 29 returned completed questionnaires of whom 26 trainees regularly stored sensitive patient data for audit or research purposes on a computer. Only one person was registered under the Data Protection Act, 1988. Of the computers used to store and analyse sensitive data, only 3 of 14 desktops, 8 of 19 laptops and 3 of 14 hand-held computers forced a password logon. Of the 29 trainees, 16 used the same password for all machines, and 25 of 27 passwords were less than 8 characters long. Two respondents declined to reveal details of their secure passwords. Half of all trainees had never adjusted their internet security settings, despite all 14 desktops, 16 of 19 laptops and 5 of 14 hand-helds being routinely connected to the internet. Of the 29 trainees, 28 never encrypted their sensitive data files. Ten trainees had sent unencrypted sensitive patient data over the internet, using a non-secure server.

CONCLUSIONS

Electronic data confidentiality practices amongst Northern Ireland surgical trainees are unsafe. Simple practical measures to safeguard confidentiality are recommended.

Diffuse Coronary Artery Disease and Dystrophic Calcification of the Radial Artery- Is There an Association?

Arterial revascularization is an attractive surgical option in the management of coronary artery disease (CAD). In the recent years, the radial artery (RA) has enjoyed resurgence in popularity as the preferred arterial conduit of choice after the internal mammary artery. Despite renewed interest in RA conduits, little is known of the prevalence of preexisting disease in this vessel, and in particular which patient subgroups are most affected, hence implications for long-term graft patency remain uncertain. We present our experience of three patients with diffuse CAD, found to have dystrophic calcification of their radial arteries intraoperatively. In all cases, the radial arteries were used, and the patients remain well and symptom-free. Soft tissue X-rays of the contra lateral forearm taken postoperatively demonstrated obvious calcification in the radial arteries in all patients. Diffuse CAD may reflect calcific disease in the RA. Suitability of a calcified RA as a conduit for CABG depends on long-term patency, which requires further evaluation.

Mesenteric lymph duct ligation decreases red blood cell alterations caused by acute pancreatitis

BACKGROUND

Both experimental and clinical studies have shown that acute pancreatitis (AP) causes a significant decrease in red blood cell (RBC) deformability. The mechanisms by which AP induces RBC injury are unknown. The purpose of this study was to test the hypothesis that factors carried in the mesenteric lymph after an attack of AP significantly contribute to the RBC injury observed in AP.

METHODS

RBC deformability was determined by means of laser-assisted ektacytometry in mesenteric lymph duct-ligated and non-ligated rats subjected to AP and in sham-operated animals.

RESULTS

AP was associated with significant alterations of RBC deformability indices, namely the elongation index and half maximal RBC elongation. Pancreatitis-induced RBC deformability changes were partially prevented by mesenteric lymph duct ligation.

CONCLUSIONS

Mesenteric lymph in AP contains factors that cause RBC damage, which is manifested by decreased deformability. Interruption of the lymph flow from the injured gut into the bloodstream decreases these RBC alterations.