Low circulating concentrations of citrulline and FGF19 predict chronic cholestasis and poor survival in adult patients with chronic intestinal failure: development of a Model for End-Stage Intestinal Failure (MESIF risk score)

Contains fulltext : 205171.pdf (publisher's version ) (Open Access)BACKGROUND: Patients with chronic intestinal failure (CIF) often develop cholestatic liver injury, which may lead to liver failure and need for organ transplantation. OBJECTIVES: The aim of this study was to investigate whether citrulline (CIT) and the enterokine fibroblast growth factor 19 (FGF19) are associated with chronic cholestasis and survival in adult CIF patients, and to develop a risk score to predict their survival. METHODS: We studied 135 adult CIF patients on intravenous supplementation (>3 mo). Associations of plasma CIT and FGF19 with chronic cholestasis and survival were estimated by logistic and Cox regression models. A predictive risk score was developed and validated internally. RESULTS: Patients with chronic cholestasis (17%) had a reduced 5-y survival rate compared with patients without chronic cholestasis (38% and 62%, respectively). In multivariable analysis, low FGF19, low CIT, and female sex were associated with chronic cholestasis. Patients with low rather than high CIT or FGF19 also had reduced 5-y survival rates (29% compared with 69%; 54% compared with 66%, respectively). Risk factors identified in multivariable analysis of survival were low FGF19 (HR: 3.4), low CIT (HR: 3.3), and number of intravenous infusions per week (HR: 1.4). These 3 predictors were incorporated in a risk model of survival termed Model for End-Stage Intestinal Failure (MESIF) (C-statistic 0.78). The 5-y survival rates for patients with MESIF scores of 0 to 40 (n = 13) were 80%, 58%, and 14%, respectively. CONCLUSIONS: CIT and FGF19 predict chronic cholestasis and survival in this cohort of adult CIF patients, and the derived MESIF score is associated with their survival. Pending external validation, the MESIF score may help to identify patients for closer clinical monitoring or earlier referral to intestinal transplantation centers

Kinetic modelling of quantitative proteome data predicts metabolic reprogramming of liver cancer

BACKGROUND: Metabolic alterations can serve as targets for diagnosis and cancer therapy. Due to the highly complex regulation of cellular metabolism, definite identification of metabolic pathway alterations remains challenging and requires sophisticated experimentation. METHODS: We applied a comprehensive kinetic model of the central carbon metabolism (CCM) to characterise metabolic reprogramming in murine liver cancer. RESULTS: We show that relative differences of protein abundances of metabolic enzymes obtained by mass spectrometry can be used to assess their maximal velocity values. Model simulations predicted tumour-specific alterations of various components of the CCM, a selected number of which were subsequently verified by in vitro and in vivo experiments. Furthermore, we demonstrate the ability of the kinetic model to identify metabolic pathways whose inhibition results in selective tumour cell killing. CONCLUSIONS: Our systems biology approach establishes that combining cellular experimentation with computer simulations of physiology-based metabolic models enables a comprehensive understanding of deregulated energetics in cancer. We propose that modelling proteomics data from human HCC with our approach will enable an individualised metabolic profiling of tumours and predictions of the efficacy of drug therapies targeting specific metabolic pathways

Review article: hyperammonaemic and catabolic consequences of upper gastrointestinal bleeding in cirrhosis.

Abstract Background and Aims: Upper gastrointestinal bleeding (UGI) in patients with cirrhosis of the liver induces hyperammonemia and leads to a catabolic cascade that precipitates life-threatening complications. The haemoglobin molecule is unique because it lacks the essential amino acid isoleucine and contains high amounts of leucine and valine. UGI bleed therefore presents the gut with protein of very low biologic value, which may be the stimulus to induce net catabolism. Results: It has recently been proven that ('simulation') a UGI bleed in patients with cirrhosis leads to impaired protein synthesis that can be restored by intravenous infusion of isoleucine. This may have therapeutic implications for the function of rapidly dividing cells and short half-life proteins such as like clotting factors. Renal and small bowel ammoniagenesis were shown to be the most prominent causes of the hyperammonemia that resulted from a UGI bleed. This provides an explanation for the therapeutic failure of the current clinical therapies that are aimed at large bowel derived ammonia production. Isoleucine infusion did not diminish renal ammoniagenesis. Conclusions: New pharmacological therapies to diminish post-bleeding hyperammonemia should target the altered interorgan ammonia metabolism and promote ammonia excretion and/or increase the excretion of precursors of ammoniagenesis, e.g. l-ornithine-phenylacetatate

Interorgan ammonia trafficking in liver disease.

Patients with liver disease have reduced urea synthesis capacity resulting in reduced capacity to detoxify ammonia in the liver. The contribution of the gut to the hyperammonemic state observed during liver failure is mainly due to portacaval shunting and not the result of changes in the metabolism of ammonia in the gut. Small intestinal synthesis of ammonia is related to amino acid breakdown, predominantly glutamine, whereas large bowel ammonia production is caused by bacterial breakdown of amino acids and urea. The kidneys produce ammonia but adapt to liver failure in experimental portacaval shunting by reducing ammonia release into the systemic circulation. The kidneys have the ability to switch from net ammonia production to net ammonia excretion. Data from recent studies in patients with cirrhosis of the liver show that the kidneys have a major role in post upper gastrointestinal bleeding hyperammonemia. During hyperammonemia muscle takes up ammonia and plays a major role in (temporarily) detoxifying ammonia to glutamine. Net uptake of ammonia by the brain occurs in patients and experimental animals with acute and chronic liver failure. Insight will be given in recent developments on ammonia lowering therapies which are based on the information of interorgan ammonia trafficking

Protein synthesis is severely diminished following a simulated upper GI bleed in patients with cirrhosis.

BACKGROUND/AIMS: An upper gastrointestinal (GI) bleed in cirrhotic patients has been hypothesised to induce catabolism due to the absence of the essential branched chain amino acid (BCAA) isoleucine and an abundance of the BCAA leucine in haemoglobin. We tested whether an upper GI bleed produces hypoisoleucinemia via BCAA antagonism and impairs protein synthesis. METHODS: Isoleucine turnover and oxidation was studied in 5 metabolically stable patients with cirrhosis during a 4-h period of intragastric saline infusion followed by a 4-h period in which an upper GI bleed was simulated by an amino acid solution mimicking haemoglobin. RESULTS: The simulated upper GI bleed induced hypoisoleucinemia (26% of initial values) and an increase in leucine (400%) and valine (350%) concentrations. Isoleucine flux and isoleucine oxidation decreased to a third of initial values following a simulated bleed, but the fraction of isoleucine flux used for oxidation did not change. Consequently, the non-oxidative portion of isoleucine flux, representing protein synthesis, decreased similarly. CONCLUSIONS: The present study shows that a simulated upper GI bleed induces hypoisoleucinemia and decreases protein synthesis markedly. The fact that the percentage of isoleucine flux that was oxidized was not influenced by the hypoisoleucinemic state can only be explained by BCAA antagonism

Treatment strategies in 135 consecutive patients with enterocutaneous fistulas

BACKGROUND: Enterocutaneous fistulas (ECF) pose a major challenge to every gastrointestinal (GI) surgeon. Based on earlier studies, a standardized treatment guideline was implemented. The focus of the present study was to assess that guideline and determine prognostic factors for outcome of patients with ECF, and to define a more detailed therapeutic approach including the convalescence time before restorative surgery. METHODS: All patients with ECF treated between 1990 and 2005 were included. Management consisted of controlling Sepsis, Optimization of nutritional state, Wound care, assessment of fistula Anatomy, Timing of surgery, and Surgical strategy (the SOWATS guideline). Prognostic factors were assessed by way of multiple logistic regression analysis. RESULTS: A total of 135 patients were treated at our unit. Overall closure was achieved in 118 patients (87.4%). Restorative operations for fistula closure were performed after a median of 53 days (range: 4–270 days). Restorative operations were successful in 97/107 patients (90.7%). Thirteen patients (9.6%) died. An abdominal wall defect was the most predominant negative prognostic factor for spontaneous closure (odds ratio [OR] = 0.195, confidence interval [CI] 0.052–0.726, p = 0.015). A strong relation was found between preoperative albumin level and surgical closure (p < 0.001) and mortality (p < 0.001). CONCLUSIONS: Application of the SOWATS guideline allowed a favorable outcome after a short convalescence period. Abdominal wall defects and preoperative hypoalbuminemia are important prognostic variables

Short chain fatty acids exchange: Is the cirrhotic, dysfunctional liver still able to clear them?

BACKGROUND & AIMS: Prebiotics are increasingly used to improve gut integrity. A presumed mechanism of their beneficial action is the synthesis of short chain fatty acids (SCFA: acetate, propionate and butyrate). High systemic concentrations of propionate and butyrate are toxic and can adversely affect the patient. In physiological situations the liver uses propionate and butyrate for energy metabolism. The aim of the present study was to investigate to which extent patients with liver cirrhosis are still able to metabolize portal derived SCFA in the liver. METHODS: Twelve patients with liver cirrhosis and an intrahepatic portosystemic shunt (TIPSS) were studied. Blood was sampled from the femoral artery, portal and hepatic vein. Organ plasma flow was measured. Net release or uptake was calculated by multiplying the arteriovenous differences by plasma flow. SCFA plasma concentrations were measured using LC-MS. RESULTS: Arterial concentrations were 124+/-12, 8+/-1 and 10+/-1mumol/l for acetate, propionate and butyrate, respectively. The gut produced 32.5+/-13.0, 4.8+/-1.3 and 6.2+/-2.1mumolkgbw(-1)h(-1) of acetate, propionate and butyrate, respectively. Assuming 70% portosystemic shunting, hepatic uptake of propionate and butyrate was 3.1+/-0.9 and 5.2+/-1.4mumolkgbw(-1)h(-1). Hepatic uptake of acetate was non significant (12.1+/-12.3mumolkgbw(-1)min(-1)). As a consequence of shunting, part of total acetate escaped from the splanchnic bed, which equalled 34.9+/-14.7mumolkgbw(-1)h(-1). CONCLUSION: The liver of patients with stable cirrhosis is able to use butyrate and propionate, most likely preventing increased systemic concentrations. This suggests that prebiotics can be administered safely, but monitoring butyrate levels may be advisable in patients with diminished liver function