Luminal GIHost genetics of Irritable bowel syndrome: more clues towards inflammation and infection
Irritable bowel syndrome (IBS) shows a familial tendency but studying host genetic factors in this condition is fraught with difficulty due to vaguely defined phenotypes. One in five of IBS begins with an acute gastroenteritis; this is defined as post-infectious IBS (PI-IBS). Given the similarity between PI-IBS and diarrhoea-predominant IBS (IBS-D), Swan et al hypothesised that IBS-D would be characterised by a genetic tendency to overreact to infectious or inflammatory insults and to show persistent immune activation. In order to test this hypothesis, the authors carried out two studies: in the first, they assessed gene expression analysis in rectal biopsies and peripheral blood mononuclear cell cytokine production in healthy volunteers, patients 6 months after Campylobacter jejuni infection, IBS-D and IBS with constipation (IBS-C) patients. In part 2, polymorphisms in genes whose expression was altered...
The paper by Kanda et al highlights a potentially novel method for the early diagnosis of pancreatic neoplasia.1 Although our understanding of the pathological and molecular events of pancreatic cancer has advanced significantly over the past years, we are still far away from a clinically meaningful breakthrough in its treatment as demonstrated by the poor survival statistics which have hardly changed over the past decades.23 In light of this sobering observation, it is important to consider other ways of trying to lower the mortality of this dreadful disease. Primary prevention through life style changes of established risk factors like smoking has a considerable potential to reduce the number of pancreatic cancer deaths,4 but it is well known that such behavioural changes are difficult to accomplish. Secondary prevention by screening the general population for pancreatic cancer is not feasible at present...
Alcoholic liver disease (ALD) is a major cause of liver-related morbidity and mortality worldwide.1 Although the most effective therapy for patients with ALD is alcohol cessation, targeted therapies are needed in patients with progressive disease and active drinking, and for those with life-threatening conditions such as alcoholic hepatitis. The development of such therapies is hampered by poor knowledge of the main disease drivers. During the last two decades, the cellular and molecular mechanisms of the hepatic wound-healing response to repeated exposure to alcohol have been partially delineated. ALD is characterised by steatosis, inflammatory infiltrate mainly composed of polymorphonuclear cells, hepatocellular injury and progressive fibrosis. The cellular and molecular basis includes paracrine stimulation by damaged hepatocytes, the innate immune system, oxidative stress and the resulting activation of non-parenchymal cells. Several inflammatory and fibrogenic mediators are released at the areas of tissue repair and perpetuate inflammation, leading to progressive...
Ulcerative colitis (UC) is a chronic, disabling, progressive inflammatory bowel disease (IBD).1 The condition is associated with an increased risk of colorectal cancer and other serious structural and functional consequences in the long term,1 which include the development of colonic strictures, dysmotility, anorectal dysfunction and impaired permeability.1 In this context, mucosal healing has emerged as a new therapeutic goal in the prevention of the long-term complications of IBD.23 Indeed, a growing body of evidence indicates that mucosal healing improves the natural course of the disease by lowering the need for colectomy and thus reducing hospitalisation rates in these patients.3 Histological healing is considered as the ultimate marker of quiescent disease activity in UC4 and thus an improvement in the patient's quality of life. However, it is not yet known whether persistent gene...
This study assessed the associations between hospital volume, resection rate and survival of oesophageal and gastric cancer patients in England.
62 811 patients diagnosed with oesophageal or gastric cancer between 2004 and 2008 were identified from a national population-based cancer registration and Hospital Episode Statistics-linked dataset. Cox regression analyses were used to assess all-cause mortality according to hospital volume and resection rate, adjusting for case-mix variables (sex, age, socioeconomic deprivation, comorbidity and type of cancer). HRs and 95% CIs, according to hospital volume, were evaluated for three predefined periods following surgery: <30, 30–365, and >365 days. Analysis of mortality in relation to resection rate was performed among all patients and among the 13 189 (21%) resected patients.
Increasing hospital volume was associated with lower mortality (ptrend=0.0001; HR 0.87, 95% CI 0.79 to 0.95 for hospitals resecting 80+ and compared with <20 patients a year). In relative terms, the association between increasing hospital volume and lower mortality was particularly strong in the first 30 days following surgery (ptrend<0.0001; HR 0.52, (0.39 to 0.70)), but a clinically relevant association remained beyond 1 year (ptrend=0.0011; HR 0.82, (0.72 to 0.95)). Increasing resection rates were associated with lower mortality among all patients (ptrend<0.0001; HR 0.86, (0.84 to 0.89) for the highest, compared with the lowest resection quintile).
With evidence of lower short-term and longer-term mortality for patients resected in high-volume hospitals, this study supports further centralisation of oesophageal and gastric cancer surgical services in England.
Ulcerative colitis (UC) is a chronic condition characterised by the relapsing inflammation despite previous endoscopic and histological healing. Our objective was to identify the molecular signature associated with UC remission.
We performed whole-genome transcriptional analysis of colonic biopsies from patients with histologically active and inactive UC, and non-inflammatory bowel disease (non-IBD) controls. Real-time reverse transcriptase-PCR and immunostaining were used for validating selected genes in independent cohorts of patients.
Microarray analysis (n=43) demonstrates that UC patients in remission present an intestinal transcriptional signature that significantly differs from that of non-IBD controls and active patients. Fifty-four selected genes were validated in an independent cohort of patients (n=30). Twenty-nine of these genes were significantly regulated in UC-in-remission subjects compared with non-IBD controls, including a large number of epithelial cell-expressed genes such as REG4, S100P, SERPINB5, SLC16A1, DEFB1, AQP3 and AQP8, which modulate epithelial cell growth, sensitivity to apoptosis and immune function. Expression of inflammation-related genes such as REG1A and IL8 returned to control levels during remission. REG4, S100P, SERPINB5 and REG1A protein expression was confirmed by immunohistochemistry (n=23).
Analysis of the gene signature associated with remission allowed us to unravel pathways permanently deregulated in UC despite histological recovery. Given the strong link between the regulation of some of these genes and the growth and dissemination of gastrointestinal cancers, we believe their aberrant expression in UC may provide a mechanism for epithelial hyper-proliferation and, in the context of malignant transformation, for tumour growth.
Multiple genes have been implicated by association studies in altering inflammatory bowel disease (IBD) predisposition. Paediatric patients often manifest more extensive disease and a particularly severe disease course. It is likely that genetic predisposition plays a more substantial role in this group.
To identify the spectrum of rare and novel variation in known IBD susceptibility genes using exome sequencing analysis in eight individual cases of childhood onset severe disease.
DNA samples from the eight patients underwent targeted exome capture and sequencing. Data were processed through an analytical pipeline to align sequence reads, conduct quality checks, and identify and annotate variants where patient sequence differed from the reference sequence. For each patient, the entire complement of rare variation within strongly associated candidate genes was catalogued.
Across the panel of 169 known IBD susceptibility genes, approximately 300 variants in 104 genes were found. Excluding splicing and HLA-class variants, 58 variants across 39 of these genes were classified as rare, with an alternative allele frequency of <5%, of which 17 were novel. Only two patients with early onset Crohn's disease exhibited rare deleterious variations within NOD2: the previously described R702W variant was the sole NOD2 variant in one patient, while the second patient also carried the L1007 frameshift insertion. Both patients harboured other potentially damaging mutations in the GSDMB, ERAP2 and SEC16A genes. The two patients severely affected with ulcerative colitis exhibited a distinct profile: both carried potentially detrimental variation in the BACH2 and IL10 genes not seen in other patients.
For each of the eight individuals studied, all non-synonymous, truncating and frameshift mutations across all known IBD genes were identified. A unique profile of rare and potentially damaging variants was evident for each patient with this complex disease.
The postinfectious irritable bowel syndrome (PI-IBS) suggests that impaired resolution of inflammation could cause IBS symptoms. The authors hypothesised that polymorphisms in genes whose expression were altered by gastroenteritis might be linked to IBS with diarrhoea (IBS-D) which closely resembles PI-IBS.
Part 1: 25 healthy volunteers (HVs), 21 patients 6 months after Campylobacter jejuni infection, 37 IBS-D and 19 IBS with constipation (IBS-C) underwent rectal biopsy for gene expression analysis and peripheral blood mononuclear cell cytokine production assessment. Part 2: Polymorphisms in genes whose expression was altered in Part 1 were assessed in 179 HV, 179 IBS-D, 122 IBS-C and 41 PI-IBS.
Part 1: Mucosal expression of seven genes was altered in IBS: CCL11, CCL13, Calpain 8 and TNFSF15 increased while NR1D1, GPR161 and GABRE decreased with similar patterns after infection with C jejuni. Part 2: The authors assessed 21 known single nucleotide polymorphisms (SNPs) in these seven genes and one SNP in each of the TNFα and IL-10 genes. Three out of five TNFSF15 SNPs (rs6478108, rs6478109 and rs7848647) showed reduced minor allele frequency (MAF) (0.28, 0.27 and 0.27) in subjects with IBS-D compared with HV (0.38, 0.36 and 0.37; p=0.007, 0.015 and 0.007, respectively) confirming others recent findings. The authors also replicated the previously reported association of the TNFα SNP rs1800629 with PI-IBS which showed an increase in the MAF at 0.30 versus 0.19 for HV (p=0.04).
IBS-D and PI-IBS patients are associated with TNFSF15 and TNFα genetic polymorphisms which also predispose to Crohn's disease suggesting possible common underlying pathogenesis.
A 17-year-old woman of Afro-Caribbean origin presented with a 1 month history of abdominal pain associated with vomiting and weight loss. Symptoms had gradually become more frequent and persistent. She had previously been well and had no previous hospital attendances or illnesses.
Vital signs and physical examination was normal with the exception of tenderness in the epigastrium on palpation.
Initial bloods tests revealed the following abnormalities only; platelets 520, alkaline phosphatase 169, C-reactive protein 73, international normalised ratio 1.3.
An x-ray of her chest was abnormal with bilateral reticular nodular shadowing and CT of her chest, abdomen and pelvis showed multiple ill-defined spiculated nodules seen throughout all lung fields, as well as an abnormally thickened stomach with adjacent prominent perigastric nodules. Gastroscopy showed oedema and inflammation of the gastric folds. Blood cultures, autoantibody and viral screens were negative.
Images from the CT of the lungs and the stomach, upper...
Coeliac disease is defined by gluten responsiveness, yet there are few data on gluten challenge (GC) in adults on a gluten-free diet. Lack of data regarding the kinetics of responses to gluten is a limitation in clinical practice and research when GC is performed.
20 adults with biopsy-proven coeliac disease participated. The study included two run-in visits followed by a 14-day GC at a randomly assigned dose of 3 or 7.5 g of gluten/day. Study visits occurred 3, 7, 14 and 28 days after starting GC. Duodenal biopsy was performed during the run-in and at days 3 and 14 of GC. Villous height to crypt depth ratio (Vh:Cd) and intraepithelial lymphocyte (IEL) count/100 enterocytes were measured by two pathologists. Antibodies to tissue transglutaminase and deamidated gliadin peptides, lactulose to mannitol ratio (LAMA) and symptoms were assessed at each visit.
Significant reduction in Vh:Cd (2.2–1.1, p<0.001) and increase in IELs (32.6–51.8, p<0.001) were seen from baseline to day 14. Antibody titres increased slightly from baseline to day 14 of GC but markedly by day 28. LAMA did not change significantly. Gastrointestinal symptoms increased significantly by day 3 and returned to baseline by day 28. No differences were seen between the two gluten doses.
14 day GC at ≥3 g of gluten/day induces histological and serological changes in the majority of adults with coeliac disease. These data permit accurate design of clinical trials and indicate that many individuals will meet coeliac diagnostic criteria after a 2-week GC.
The abdominoperineal excision (APE) rate, a quality of care indicator in rectal cancer surgery, has been criticised if not adjusted for confounding factors. This study evaluates variability in APE rate between centres participating in PROCARE, a Belgian improvement initiative, before and after risk adjustment. It also explores the effect of merging the Hartmann resections (HR) rate with that of APE on benchmarking.
Data of 3197 patients who underwent elective radical resection for invasive rectal adenocarcinoma up to 15 cm were registered between January 2006 and March 2011 by 59 centres, each with at least 10 patients in the registry. Variability of APE or merged APE/HR rates between centres was analysed before and after adjustment for gender, age, ASA score (3 or more), tumour level (rectal third), depth of tumour invasion (cT4) and preoperative incontinence.
The overall APE rate was 21.1% (95% CI 19.7 to 22.5%). Significant variation of the APE rate was observed before and after risk adjustment (p<0.0001). For cancers in the lower rectal third, the overall APE rate increased to 45.8% (95% CI 43.1 to 48.5%). Also, variation between centres increased. Risk adjustment influenced the identification of outliers. HR was performed in only 2.6% of patients. However, merging of risk adjusted APE and HR rates identified other centres with outlying definitive colostomy rates than APE rate alone.
Significant variation of the APE rate was observed. Adjustment for confounding factors as well as merging HR with APE rates were found to be important for the assessment of performances.
Wnt/Tcf, Lgr5, Ascl2 and/or Bmi1 signalling is believed to define the mouse intestinal stem cell niche(s) from which adenomas arise. The aim of this study was to determine the relevance of these putative intestinal stem cell markers to human colorectal cancer.
19 putative intestinal stem cell markers, including Ascl2 and Lgr5, were identified from published data and an evaluation of a human colorectal gene expression database. Associations between these genes were assessed by isotopic in situ hybridisation (ISH) in 57 colorectal adenocarcinomas. Multiplex fluorescent ISH and chromogenic non-isotopic ISH were performed to confirm expression patterns. The prognostic significance of Lgr5 was assessed in 891 colorectal adenocarcinomas.
Ascl2 and Lgr5 were expressed in 85% and 74% of cancers respectively, and expression was positively correlated (p=0.003). Expression of Bmi1 was observed in 47% of cancers but was very weak in 98% of cases with expression. Both Ascl2 and/or Lgr5 were positively correlated with the majority of genes in the signature but neither was correlated with Cdk6, Gpx2, Olfm4 or Tnfrsf19. Lgr5 did not have prognostic significance.
These data suggest that 74–85% of colorectal cancers express a Lgr5/Ascl2 associated signature and support the hypothesis that they derive from Lgr5+/Ascl2+ crypt stem cells, not Bmi1+ stem cells. However, Olfm4 was not found to be a useful marker of Lgr5+ cells in normal colon or tumours. In this large series, Lgr5 expression is not associated with increased tumour aggressiveness, as might be expected from a cancer stem cell marker.
Pancreatic cysts are commonly detected in patients undergoing pancreatic imaging. Better approaches are needed to characterise these lesions. In this study we evaluated the utility of detecting mutant DNA in secretin-stimulated pancreatic juice.
Secretin-stimulated pancreatic juice was collected from the duodenum of 291 subjects enrolled in Cancer of the Pancreas Screening trials at five US academic medical centres. The study population included subjects with a familial predisposition to pancreatic cancer who underwent pancreatic screening, and disease controls with normal pancreata, chronic pancreatitis, sporadic intraductal papillary mucinous neoplasm (IPMN) or other neoplasms. Somatic GNAS mutations (reported prevalence ~66% of IPMNs) were measured using digital high-resolution melt-curve analysis and pyrosequencing.
GNAS mutations were detected in secretin-stimulated pancreatic juice samples of 50 of 78 familial and sporadic cases of IPMN(s) (64.1%), 15 of 33 (45.5%) with only diminutive cysts (<5 mm), but none of 57 disease controls. GNAS mutations were also detected in five of 123 screened subjects without a pancreatic cyst. Among 97 subjects who had serial pancreatic evaluations, GNAS mutations detected in baseline juice samples predicted subsequent emergence or increasing size of pancreatic cysts.
Duodenal collections of secretin-stimulated pancreatic juice from patients with IPMNs have a similar prevalence of mutant GNAS to primary IPMNs, indicating that these samples are an excellent source of mutant DNA from the pancreas. The detection of GNAS mutations before an IPMN is visible suggests that analysis of pancreatic juice has the potential to help in the risk stratification and surveillance of patients undergoing pancreatic screening.
Novel imaging methods based on specific molecular targets to detect both established neoplasms and their precursor lesions are highly desirable in cancer medicine. Previously, we identified claudin-4, an integral constituent of tight junctions, as highly expressed in various gastrointestinal tumours including pancreatic cancer. Here, we investigate the potential of targeting claudin-4 with a naturally occurring ligand to visualise pancreatic cancer and its precursor lesions in vitro and in vivo by near-infrared imaging approaches.
A non-toxic C-terminal fragment of the claudin-4 ligand Clostridium perfringens enterotoxin (C-CPE) was labelled with a cyanine dye (Cy5.5). Binding of the optical tracer was analysed on claudin-4 positive and negative cells in vitro, and tumour xenografts in vivo. In addition, two genetically engineered mouse models for pancreatic intraepithelial neoplasia (PanIN) and pancreatic cancer were used for in vivo validation. Optical imaging studies were conducted using 2D planar fluorescence reflectance imaging (FRI) technology and 3D fluorescence-mediated tomography (FMT).
In vitro, the peptide-dye conjugate showed high binding affinity to claudin-4 positive CAPAN1 cells, while claudin-4 negative HT1080 cells revealed little or no fluorescence. In vivo, claudin-4 positive tumour xenografts, endogenous pancreatic tumours, hepatic metastases, as well as preinvasive PanIN lesions, were visualised by FRI and FMT up to 48 h after injection showing a significantly higher average of fluorochrome concentration as compared with claudin-4 negative xenografts and normal pancreatic tissue.
C-CPE-Cy5.5 combined with novel optical imaging methods enables non-invasive visualisation of claudin-4 positive murine pancreatic tumours and their precursor lesions, representing a promising modality for early diagnostic imaging.
The hepatic endocannabinoid system and cytochrome P450 2E1 (CYP2E1), a key enzyme causing alcohol-induced reactive oxygen species (ROS) generation, are major contributors to the pathogenesis of alcoholic liver disease. The nuclear hormone receptor oestrogen-related receptor (ERR) is a constitutively active transcriptional activator regulating gene expression.
To investigate the role of ERR in the alcohol-mediated regulation of CYP2E1 and to examine the possibility to control alcohol-mediated oxidative stress and liver injury through an ERR inverse agonist.
For chronic alcoholic hepatosteatosis study, C57BL/6J wild-type and CB1–/– mice were administered alcohol for 4 weeks. GSK5182 and chlormethiazole (CMZ) were given by oral gavage for the last 2 weeks of alcohol feeding. Gene expression profiles and biochemical assays were performed using the liver or blood of mice.
Hepatic ERR gene expression induced by alcohol-mediated activation of CB1 receptor results in induction of CYP2E1, while liver-specific ablation of ERR gene expression blocks alcohol-induced expression of CYP2E1 in mouse liver. An ERR inverse agonist significantly ameliorates chronic alcohol-induced liver injury in mice through inhibition of CYP2E1-mediated generation of ROS, while inhibition of CYP2E1 by CMZ abrogates the beneficial effects of the inverse agonist. Finally, chronic alcohol-mediated ERR and CYP2E1 gene expression, ROS generation and liver injury in normal mice were nearly abolished in CB1–/– mice.
ERR, as a previously unrecognised transcriptional regulator of hepatic CB1 receptor, controls alcohol-induced oxidative stress and liver injury through CYP2E1 induction, and its inverse agonist could ameliorate oxidative liver injury due to chronic alcohol exposure.
We recently demonstrated that combination treatment with NS3 protease and NS5B polymerase inhibitors succeeded in eradicating the virus in genotype 1b hepatitis C virus (HCV)-infected mice. In this study, we investigated the effect of combining an NS5A replication complex inhibitor (RCI) with either NS3 protease or NS5B inhibitors on elimination of HCV genotypes 1b, 2a and 2b.
The effects of Bristol-Myers Squibb (BMS)-605339 (NS3 protease inhibitor; PI), BMS-788329 (NS5A RCI) and BMS-821095 (NS5B non-nucleoside analogue inhibitor) on HCV genotypes 1b and 2a were examined using subgenomic HCV replicon cells. HCV genotype 1b, 2a or 2b-infected human hepatocyte chimeric mice were also treated with BMS-605339, BMS-788329 or BMS-821095 alone or in combination with two of the drugs for 4 weeks. Genotypic analysis of viral sequences was achieved by direct and ultra-deep sequencing.
Anti-HCV effects of BMS-605339 and BMS-821095 were more potent against genotype 1b than against genotype 2a. In in-vivo experiments, viral breakthrough due to the development of a high prevalence of drug-resistant variants was observed in mice treated with BMS-605339, BMS-788329 and BMS-821095 in monotherapy. In contrast to monotherapy, 4 weeks of combination therapy with the NS5A RCI and either NS3 PI or NS5B inhibitor succeeded in completely eradicating the virus in genotype 1b HCV-infected mice. Conversely, these combination therapies failed to eradicate the virus in mice infected with HCV genotypes 2a or 2b.
These oral combination therapies may serve as a Peg-alfa-free treatment for patients chronically infected with HCV genotype 1b.
Intestinal epithelial cells (IEC) are organised as a single cell layer which covers the intestine. Their primary task is to absorb nutrients present in the intestinal lumen. However, IEC also play an important role in the immune defence of our body by building a barrier that separates the bowel wall from potentially hazardous bacteria present in the gut lumen. The life cycle of IEC is determined by the time span in which cells migrate from their place of origin at the crypt base to the villus tip, from where they are shed into the lumen. Cell death in the intestinal epithelium has to be tightly regulated and irregularities might cause pathologies. Excessive cell death has been associated with chronic inflammation as seen in patients with Crohn's disease and ulcerative colitis. While until recently apoptosis was discussed as being essential for epithelial turnover and tissue homeostasis in the intestinal epithelium, recent data using gene deficient mice have challenged this concept. Moreover, an apoptosis-independent mode of programmed cell death, termed necroptosis, has been identified and described in the intestinal epithelium. The following article reviews previous studies on cell death regulation in IEC and a potential role of necroptosis for gut homeostasis.
The occurrence of strictures as a complication of Crohn's disease is a significant clinical problem. No specific antifibrotic therapies are available. This systematic review comprehensively addresses the pathogenesis, epidemiology, prediction, diagnosis and therapy of this disease complication. We also provide specific recommendations for clinical practice and summarise areas that require future investigation.
Basic scienceCan the gut microbiota contribute to the emergence of antibiotic resistance?
Forslund K, Sunagawa S, Roat Kultima J, et al. Country-specific antibiotic use practices impact the human gut resistome. Genome Res Published Online First: 8 April 2013. doi:10.1101/gr.155465.113
The human gut microbiota is considered a reservoir for antibiotic resistance genes (ARGs). With increasing concerns over inappropriate antibiotic usage both in medicine and agriculture, the development of bacterial resistance mechanisms is of great concern. These resistance mechanisms can be transferred via mobile genetic elements such as plasmids or transposons and therefore horizontal transfer within the gut is likely. To date there have been limited attempts to determine the antibiotic resistance potential of the human gut microbiota. This is in spite of the insatiable demand for delineation of the gut microbiome in almost every conceivable disease state—many of which require antibiotic intervention. This recent study from Germany...
We read with great interest the article by Worthley et al1 that recently appeared in your Journal, and the subsequent letter on the same subject.2 We would like to make some comments on this interesting topic.
Worthley et al reported a new autosomal dominant syndrome that they named gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). GAPPS appears to be characterised by proximal gastric polyposis, particularly of the fundic gland type that often displays low and high grade dysplasia with early development of gastric cancer. These patients showed no evidence of colonic polyps, and other genetic syndromes were excluded. Yanaru-Fujisawa et al reported a further family with GAPPS.
So far, dysplasia has been described infrequently in sporadic fundic gland polyps (FGPs) and even the more frequent dysplasia in FGPs associated with familial adenomatous polyposis (<1 and 30%, respectively),3 is usually superficial and...
We read with interest the recent review by Wiest et al1 on spontaneous bacterial peritonitis (SBP), and would like to point out a new mechanism involved in the pathogenesis of this phenomenon. Cirrhotic patients have altered host-defence response mechanisms and increased susceptibility to bacterial infections, which seem to be related to alterations in the intestinal barrier and/or bacterial translocation from the mucosa to the mesenteric lymph nodes and the intestinal circulation. For this reason, a better understanding on the causes underlying this infection is important for effective future therapies. Both liver cirrhosis and lipopolyshaccaride (LPS)-induced sepsis have been associated with increased activity of endogenous cannabinoids.23 Our study aims to expand the knowledge on the relationship between Cannabinoid receptor 2 (CB2) receptors and SBP. We analysed the mRNA expression of CB2 in cirrhotic patients with or without SBP, with a mean age of...
In their important study, Tsien et al1 demonstrated for the first time that minor increases of serum creatinine have major clinical impact in outpatients with cirrhosis, ascites and normal serum creatinine. Patients with acute kidney injury (AKI) had a slow constant increase of serum creatinine over time and, interestingly, a reduced survival probability. These data support the concept that not only hepatorenal syndrome, but also minor changes of normal serum creatinine may have clinical importance.23 However, no predictors of reversal of AKI could be identified. Possibly, more sensitive markers of reduced glomerular filtration rate, such as cystatin C4 or NGAL,5 may be suitable predictors. Another aspect of AKI remains to be elucidated: AKI stage 1 is defined by an increase of serum creatinine of at least 50% or 0.3 mg/dl over serum baseline. These changes, however, may denote different...
The definition of renal dysfunction in cirrhosis is undergoing some changes in recent times.1 Although the definition of hepatorenal syndrome2 has served the hepatology community very well by identifying patients with cirrhosis, who are severely ill with advanced kidney failure in the presence of liver failure, many of these patients are so ill that they are no longer responsive to our currently available therapies for hepatorenal syndrome. Therefore, it was proposed that the definition of renal dysfunction in cirrhosis should be modified adapting to the guidelines proposed by the acute kidney injury (AKI) network.3 The proposed definition allows for a diagnosis of AKI whenever there is either a rise in serum creatinine by 0.3 mg/dl in <48 h or a rise by 50% from baseline. Using this new definition, many patients whose renal dysfunction may have been overlooked previously can now be identified,...