Frequent molecular identification of Campylobacter but not Helicobacter genus in bile and biliary epithelium in hepatolithiasis

The Relationship between Helicobacter pylori Infection of the Gallbladder and Chronic Cholecystitis and Cholelithiasis: A Systematic Review and Meta-Analysis

Helicobacter pylori (H. pylori) is proved to be the main pathogenic agent of various diseases, including chronic gastritis, gastric ulcer, duodenal ulcer, and gastric cancer. In addition, chronic cholecystitis and cholelithiasis are common worldwide, which are supposed to increase the total mortality of patients. Epidemiologic evidence on the relationship between H. pylori infection of the gallbladder and chronic cholecystitis/cholelithiasis still remains unclear. We conducted a systematic review and meta-analysis of overall studies to investigate the relationship between H. pylori infection of the gallbladder and chronic cholecystitis/cholelithiasis. Two researchers searched PubMed, Embase, and Cochrane Library databases to obtain all related and eligible studies published before July 2020. The pooled odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were calculated by the random-effects model. Subgroup analysis, heterogeneity, publication bias, and sensitivity analysis were also conducted. Twenty studies were included in the meta-analysis, involving 1735 participants and 1197 patients with chronic cholecystitis/cholelithiasis. Helicobacter species infection of the gallbladder was positively correlated with increased risk of chronic cholecystitis and cholelithiasis, especially H. pylori (OR = 3.05; 95% CI, 1.81-5.14; I 2 = 23.5%). Besides, country-based subgroup analysis also showed a positive correlation between the gallbladder H. pylori positivity and chronic cholecystitis/cholelithiasis risk. For Asian and non-Asian country studies, the ORs were 4.30 (95% CI, 1.76-10.50; I 2 = 37.4%) and 2.13 (95% CI, 1.23-3.70; I 2 = 0.0%), respectively. The association was more obvious using the bile sample and urease gene primer. In conclusion, this meta-analysis provided evidence that there is a positive correlation between H. pylori infection in the gallbladder and increased risk of chronic cholecystitis and cholelithiasis.

Toll-like receptor 4 shRNA attenuates lipopolysaccharide-induced epithelial-mesenchymal transition of intrahepatic biliary epithelial cells in rats

BACKGROUND AND AIM

Intrahepatic biliary epithelial cells (IBECs) of the bile duct in liver tissue of patients with hepatolithiasis promoted the development of diseases through epithelial-mesenchymal transition (EMT). This study investigated whether lipopolysaccharide (LPS), a cell-wall constituent of gram-negative bacteria, could induce EMT of IBECs and toll-like receptor 4 (TLR4) had a regulatory role via activating the nuclear factor-κB (NF-κB)/Snail signaling pathway during this process in vivo.

METHODS

TLR4 short hairpin RNA (shRNA) adenovirus or negative control shRNA (NC shRNA) adenovirus (1 × 10⁹ plaque-forming unit (PFU), respectively) was injected into the caudal vein of rats. After 96 h, 1 mg/kg LPS was infused retrogradely into the common bile duct for 48 h per rat. The effects of TLR4 shRNA on LPS-induced EMT were determined by evaluating the histopathological changes in IBECs using hematoxylin and eosin staining and the changes in the levels of EMT markers, TLR4, NF-κB p65, pNF-κB p65, and Snail using real-time polymerase chain reaction and Western blot analysis.

RESULTS

Compared with normal saline treatment, a loss of epithelial cell markers (E-cadherin and cytokeratin 7) and a gain of mesenchymal cell markers (N-cadherin and matrix metalloproteinase 2) were revealed. The levels of TLR4, NF-κB phosphorylation, and Snail significantly increased after LPS treatment, whereas pretreatment with TLR4 shRNA inhibited the LPS-induced EMT by downregulating the NF-κB/Snail signaling pathway.

CONCLUSIONS

LPS induced the EMT of IBECs by activating TLR4. The RNAi-mediated knockdown of TLR4 suppressed EMT occurrence via downregulating the NF-κB/Snail signaling pathway, implicating TLR4 as a new target for human hepatolithiasis.

Helicobacter Pylori infection of the gallbladder and the risk of chronic cholecystitis and cholelithiasis: A systematic review and meta-analysis

BACKGROUND

Helicobacter pylori is coexisted with various diseases, including chronic gastritis, ulcer, and gastric cancer. Besides, chronic cholecystitis and cholelithiasis are extremely widespread over the world, which are considered as high health-care cost burdens of digestive diseases. Epidemiologic evidence on Helicobacter pylori infection in gallbladder increasing the risk of biliary diseases has been contradictory.

AIM

Conduct a meta-analysis of overall studies and investigate an association between Helicobacter pylori infection of the gallbladder with chronic cholecystitis/cholelithiasis.

METHODS

We used PubMed, EMBASE, and Cochrane library databases to identify all published studies before August 2017. Pooled odds ratios (OR) and corresponding 95% confidence intervals (CIs) were obtained using the random effects model. Heterogeneity, sensitivity, and stratified analyses were also performed.

RESULTS

Eighteen studies involving 1544 participants and 1061 biliary cases with chronic cholecystitis/cholelithiasis were included. Helicobacter pylori infection of the gallbladder was significantly associated with an increased risk of chronic cholecystitis and cholecystitis (OR = 3.022; 95% CI, 1.897-4.815; I²  = 20.1%). In addition, country-based subgroup analysis also showed a positive association between Helicobacter pylori positivity and chronic cholecystitis/cholelithiasis risk. The ORs (95% CIs) for Asian and non-Asian region studies were 3.75 (1.83-7.71) and 2.25 (1.29-3.89), respectively.

CONCLUSION

This meta-analysis suggests that infection of the gallbladder with Helicobacter pylori is closely related to an increased risk of chronic cholecystitis and cholelithiasis.

How the biliary tree maintains immune tolerance?

The liver is a vital organ with distinctive anatomy, histology and heterogeneous cell populations. These characteristics are of particular importance in maintaining immune homeostasis within the liver microenvironments, notably the biliary tree. Cholangiocytes are the first line of defense of the biliary tree against foreign substances, and are equipped to participate through various immunological pathways. Indeed, cholangiocytes protect against pathogens by TLRs-related signaling; maintain tolerance by expression of IRAK-M and PPARγ; limit immune response by inducing apoptosis of leukocytes; present antigen by expressing human leukocyte antigen molecules and costimulatory molecules; recruit leukocytes to the target site by expressing cytokines and chemokines. However, breach of tolerance in the biliary tree results in various cholangiopathies, exemplified by primary biliary cholangitis, primary sclerosing cholangitis and biliary atresia. Lessons learned from immune tolerance of the biliary tree will provide the basis for the development of effective therapeutic approaches against autoimmune biliary tract diseases. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen.

Dual role of Helicobacter and Campylobacter species in IBD: a systematic review and meta-analysis

OBJECTIVE

To conduct a comprehensive global systematic review and meta-analysis on the association between Helicobacter pylori infection and IBD. As bacterial antigen cross-reactivity has been postulated to be involved in this association, published data on enterohepatic Helicobacter spp (EHS) and Campylobacter spp and IBD was also analysed.

DESIGN

Electronic databases were searched up to July 2015 for all case-control studies on H. pylori infection/EHS/Campylobacter spp and IBD. Pooled ORs (P-OR) and 95% CIs were obtained using the random effects model. Heterogeneity, sensitivity and stratified analyses were performed.

RESULTS

Analyses comprising patients with Crohn's disease (CD), UC and IBD unclassified (IBDU), showed a consistent negative association between gastric H. pylori infection and IBD (P-OR: 0.43, p value <1e-10). This association appears to be stronger in patients with CD (P-OR: 0.38, p value <1e-10) and IBDU (P-OR: 0.43, p value=0.008) than UC (P-OR: 0.53, p value <1e-10). Stratification by age, ethnicity and medications showed significant results. In contrast to gastric H. pylori, non H. pylori-EHS (P-OR: 2.62, p value=0.001) and Campylobacter spp, in particular C. concisus (P-OR: 3.76, p value=0.006) and C. showae (P-OR: 2.39, p value=0.027), increase IBD risk.

CONCLUSIONS

H. pylori infection is negatively associated with IBD regardless of ethnicity, age, H. pylori detection methods and previous use of aminosalicylates and corticosteroids. Antibiotics influenced the magnitude of this association. Closely related bacteria including EHS and Campylobacter spp increase the risk of IBD. These results infer that H. pylori might exert an immunomodulatory effect in IBD.

TLR4, TLR9, and NLRP3 in biliary epithelial cells of primary sclerosing cholangitis: relationship with clinical characteristics

BACKGROUND AND AIM

Inappropriate innate immune responses have been suggested to contribute to the pathogenesis of primary sclerosing cholangitis (PSC). We evaluated the associations of expressions of toll-like receptor (TLR) 4, TLR9, and nucleotide-binding oligomerization domain-containing protein (NOD)-like receptor family pyrin domain containing 3 (NLRP3) in the biliary epithelial cells (BECs) with clinical features of PSC patients.

METHODS

We retrospectively evaluated the expressions of TLR4, TLR9, and NLRP3 in the intrahepatic BECs by immunohistochemical staining in 21 PSC patients and 10 normal controls. In PSC, 17 patients underwent liver biopsy, and, in the other four patients, liver specimens were obtained at the time of liver transplantation.

RESULTS

TLR9 expressions in BECs were higher in PSC patients than in normal controls. TLR9 expressions were correlated with Ludwig fibrosis scores in PSC patients. TLR4 and NLRP3 expressions were similar between PSC patients and normal controls. Seventeen PSC patients undergoing liver biopsy were followed up during a median period of 55.7 months. Four reached to liver transplantation and four developed cholangiocarcinoma. Patients developing cholangiocarcinoma showed lower NLRP3 expressions than the others. Patients reaching to liver transplantation showed higher TLR9 expressions. Expression levels of TLR9 and NLRP3 were not correlated with liver biochemical tests and Mayo risk scores.

CONCLUSIONS

In PSC, excessive immune responses through TLR9 signaling may be associated with the disease progression. Insufficient immune response through NLRP3 signaling may be associated with the development of cholangiocarcinoma. Evaluation of TLR9 and NLRP3 expressions in BECs may be useful for predicting the prognosis as an auxiliary marker.

Campylobacter showae bacteremia with cholangitis

We report a case of Campylobacter showae bacteremia associated with cholangitis. A 71-year-old man with advanced bile duct cancer was admitted to our hospital because of cholangitis with shock, hypoglycemia, and impaired renal function. After replacement of the biliary drainage tube, pus was drained from the tube. Specimens for blood and bile cultures were obtained, and fluid resuscitation and antimicrobial treatment were then begun. Although anaerobic blood culture yielded small curved gram-negative rods, the isolate could not be identified by conventional identification methods. The isolate was identified as C. showae by 16S rRNA gene sequencing analysis. We consider here the pathogenicity of C. showae and the association of C. showae with cholangitis.

Advances in cholangiocyte immunobiology

Cholangiocytes, or bile duct epithelia, were once thought to be the simple lining of the conduit system comprising the intra- and extrahepatic bile ducts. Growing experimental evidence demonstrated that cholangiocytes are in fact the first line of defense of the biliary system against foreign substances. Experimental advances in recent years have unveiled previously unknown roles of cholangiocytes in both innate and adaptive immune responses. Cholangiocytes can release inflammatory modulators in a regulated fashion. Moreover, they express specialized pattern-recognizing molecules that identify microbial components and activate intracellular signaling cascades leading to a variety of downstream responses. The cytokines secreted by cholangiocytes, in conjunction with the adhesion molecules expressed on their surface, play a role in recruitment, localization, and modulation of immune responses in the liver and biliary tract. Cholangiocyte survival and function is further modulated by cytokines and inflammatory mediators secreted by immune cells and cholangiocytes themselves. Because cholangiocytes act as professional APCs via expression of major histocompatibility complex antigens and secrete antimicrobial peptides in bile, their role in response to biliary infection is critical. Finally, because cholangiocytes release mediators critical to myofibroblastic differentiation of portal fibroblasts and hepatic stellate cells, cholangiocytes may be essential in the pathogenesis of biliary cirrhosis.

Cholangiopathy with respect to biliary innate immunity

Biliary innate immunity is involved in the pathogenesis of cholangiopathies in cases of biliary disease. Cholangiocytes possess Toll-like receptors (TLRs) which recognize pathogen-associated molecular patterns (PAMPs) and play a pivotal role in the innate immune response. Tolerance to bacterial PAMPs such as lipopolysaccharides is also important to maintain homeostasis in the biliary tree, but tolerance to double-stranded RNA (dsRNA) is not found. Moreover, in primary biliary cirrhosis (PBC) and biliary atresia, biliary innate immunity is closely associated with the dysregulation of the periductal cytokine milieu and the induction of biliary apoptosis and epithelial-mesenchymal transition (EMT), forming in disease-specific cholangiopathy. Biliary innate immunity is associated with the pathogenesis of various cholangiopathies in biliary diseases as well as biliary defense systems.

Toll-like receptors in secondary obstructive cholangiopathy

Secondary obstructive cholangiopathy is characterized by intra- or extrahepatic bile tract obstruction. Liver inflammation and structural alterations develop due to progressive bile stagnation. Most frequent etiologies are biliary atresia in children, and hepatolithiasis, postcholecystectomy bile duct injury, and biliary primary cirrhosis in adults, which causes chronic biliary cholangitis. Bile ectasia predisposes to multiple pathogens: viral infections in biliary atresia; Gram-positive and/or Gram-negative bacteria cholangitis found in hepatolithiasis and postcholecystectomy bile duct injury. Transmembrane toll-like receptors (TLRs) are activated by virus, bacteria, fungi, and parasite stimuli. Even though TLR-2 and TLR-4 are the most studied receptors related to liver infectious diseases, other TLRs play an important role in response to microorganism damage. Acquired immune response is not vertically transmitted and reflects the infectious diseases history of individuals; in contrast, innate immunity is based on antigen recognition by specific receptors designated as pattern recognition receptors and is transmitted vertically through the germ cells. Understanding the mechanisms for bile duct inflammation is essential for the future development of therapeutic alternatives in order to avoid immune-mediated destruction on secondary obstructive cholangiopathy. The role of TLRs in biliary atresia, hepatolithiasis, bile duct injury, and primary biliary cirrhosis is described in this paper.

Cholangiocyte N-Ras protein mediates lipopolysaccharide-induced interleukin 6 secretion and proliferation

Cholangiocytes, the epithelial cells lining the bile ducts in the liver, are periodically exposed to potentially injurious microbes and/or microbial products. As a result, cholangiocytes actively participate in microbe-associated, hepatic proinflammatory responses. We previously showed that infection of cultured human cholangiocytes with the protozoan parasite, Cryptosporidium parvum, or treatment with gram-negative bacteria-derived LPS, activates NFκB in a myeloid differentiation 88 (MyD88)-dependent manner. Here, we describe a novel signaling pathway initiated by Toll-like receptors (TLRs) involving the small GTPase, Ras, that mediates cholangiocyte proinflammatory cytokine production and induction of cholangiocyte proliferation. Using cultured human cholangiocytes and a Ras activation assay, we found that agonists of plasma membrane TLRs (TLR 1, 2, 4, 5, and 6) rapidly (<10 min) activated N-Ras, but not other p21 Ras isoforms, resulting in the rapid (<15 min) phosphorylation of the downstream Ras effector, ERK1/2. RNA interference-induced depletion of TRAF6, a downstream effector of MyD88 and known activator of MAPK signaling, had no effect on N-Ras activation. Following N-Ras activation the proinflammatory cytokine, IL6, is rapidly secreted. Using a luciferase reporter, we demonstrated that LPS treatment induced IL6 promoter-driven luciferase which was suppressed using MEK/ERK pharmacologic inhibitors (PD98059 or U0126) and RNAi-induced depletion of N-Ras. Finally, we showed that LPS increased cholangiocyte proliferation (1.5-fold), which was inhibited by depletion of N-Ras; TLR agonist-induced proliferation was also inhibited following pretreatment with an IL6 receptor-blocking antibody. Together, our results support a novel signaling axis involving microbial activation of N-Ras likely involved in the cholangiocyte pathogen-induced proinflammatory response.

Helicobacter pylori and pathogenesis of gallbladder cancer

BACKGROUND AND AIM

Gallbladder cancer (GBC) is a rare but leading cause of cancer-related deaths worldwide. The incidence of GBC is increasing at an alarming rate in the Varanasi region, and its etiology remains obscure.

METHODS

A total of 108 patients, 54 with GBC and 54 with gallstone diseases (GSD), were examined for Helicobacter pylori (H. pylori) in gallbladder specimens by rapid urease test, biochemical test, histology, culture, serology, polymerase chain reaction (PCR), and partial DNA sequencing. PCR was done using heat shock protein-60 (Hsp60) gene-nested primers.

RESULT

Forty (74%) patients with GBC had gallstones. Upon culture, H. pylori colonies were identified in 24 (44%) GBC and 18 (33%) GSD specimens. H. pylori was detected in 20 (37%) GBC and 15 (28%) GSD samples upon histology. Serology was positive in 17 (32%) GBC and 15 (28%) GSD patients. The DNA isolated from GBC and GSD specimens was amplified by PCR with Hsp60-nested primers in 18 (33%) patients with GBC and 15 (28%) with GSD (P > 0.05). These sequences had 98% similarity with the presubmitted Hsp60 sequences of H. pylori in the National Centre for Biotechnology Information's GenBank.

CONCLUSION

The results revealed that H. pylori was present in a large population, including both GBC and GSD patients, which indicates its endemic presence in the Varanasi region. Thus, it appears H. pylori might not have a significant role in the etiopathogenesis of GBC in our region.

Helicobacter species and common gut bacterial DNA in gallbladder with cholecystitis

AIM: To analyze the association between Helicobacter spp. and some common gut bacteria in patients with cholecystitis.

METHODS: A nested-polymerase chain reaction (PCR), specific to 16S rRNA of Helicobacter spp. was performed on paraffin-embedded gallbladder samples of 100 cholecystitis and 102 control cases. The samples were also analyzed for some common gut bacteria by PCR. Positive samples were sequenced for species identification.

RESULTS: Helicobacter DNA was found in seven out of 100 cases of acute and chronic cholecystitis. Sequence analysis displayed Helicobacter pullorum (H. pullorum) in six cases and Helicobacter pylori in one; H. pullorum was only found in cases with metaplasia. Control samples were negative for Helicobacter spp. and some common gut bacteria. There was a significant difference (P = 0.007) between cholecystitis and control samples for Helicobacter DNA.

CONCLUSION: A possible relationship was detected between Helicobacter DNA and cholecystitis. Further serological and immunohistochemical studies are needed to support these data.

Biliary innate immunity: function and modulation

Biliary innate immunity is involved in the pathogenesis of cholangiopathies in patients with primary biliary cirrhosis (PBC) and biliary atresia. Biliary epithelial cells possess an innate immune system consisting of the Toll-like receptor (TLR) family and recognize pathogen-associated molecular patterns (PAMPs). Tolerance to bacterial PAMPs such as lipopolysaccharides is also important to maintain homeostasis in the biliary tree, but tolerance to double-stranded RNA (dsRNA) is not found. In PBC, CD4-positive Th17 cells characterized by the secretion of IL-17 are implicated in the chronic inflammation of bile ducts and the presence of Th17 cells around bile ducts is causally associated with the biliary innate immune responses to PAMPs. Moreover, a negative regulator of intracellular TLR signaling, peroxisome proliferator-activated receptor-γ (PPARγ), is involved in the pathogenesis of cholangitis. Immunosuppression using PPARγ ligands may help to attenuate the bile duct damage in PBC patients. In biliary atresia characterized by a progressive, inflammatory, and sclerosing cholangiopathy, dsRNA viruses are speculated to be an etiological agent and to directly induce enhanced biliary apoptosis via the expression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). Moreover, the epithelial-mesenchymal transition (EMT) of biliary epithelial cells is also evoked by the biliary innate immune response to dsRNA.

Helicobacter species in cancers of the gallbladder and extrahepatic biliary tract

Helicobacter species have been found in human bile and biliary tract (BT) tissue and are suspected to cause BT diseases, including gallbladder and extrahepatic cancers, collectively referred to in this work as BT cancers. We conducted a literature review of the epidemiological evidence linking the presence of Helicobacter species in bile or BT biopsies to BT cancers and benign diseases. Reports showed great variability with respect to study methods. Nine studies of BT cancers were identified, all with 30 or fewer BT cancers; eight included cancer-free control subjects and used polymerase chain reaction (PCR) as a means of Helicobacter species detection. In four of these studies, Helicobacter species were detected in patients with BT cancer significantly more frequently than in controls, at least when controls without BT diseases were used. In two studies, no Helicobacter species were detected in either cases or controls. Helicobacter species were also often detected in benign BT diseases such as gallstone disease or chronic cholecystitis. As our current knowledge relies on a few small studies that showed substantial differences, larger studies and more standardised protocols for detecting DNA and antibodies against Helicobacter species are needed to investigate a potential association with BT cancer.

Genomic differences between Campylobacter jejuni isolates identify surface membrane and flagellar function gene products potentially important for colonizing the chicken intestine

Campylobacter spp. are one of the leading bacterial etiologic agents of acute human gastroenteritis among industrialized countries. Poultry are implicated as a major source of the organism for human illness; however, the factors involved with colonization of poultry gastrointestinal systems remain unclear. Genomics and proteomics analyses were used to identify differences between poor- versus robust-colonizing Campylobacter jejuni isolates, 11168(GS) and A74/C, respectively. Sequence analyses of subtracted DNA resulted in A74/C-specifc genes similar to a dimethyl sulfoxide reductase, a serine protease, polysaccharide modification proteins, and restriction modification proteins. DNA microarray analyses were performed for comparison of A74/C to the complete genome sequences published for two C. jejuni. A total of 114 genes (7.1%) were determined absent from A74/C relative to those genomes. Additionally, proteomics was completed on both soluble and membrane protein extracts from 11168(GS) and A74/C. Variation in protein expression and physical characteristics such as pI was detected between the two isolates that included the major outer membrane protein, flagella, and aconitate hydratase. Several proteins including cysteine synthase and a Ni/Fe hydrogenase were determined to be differentially present between the two isolates. Finally, DNA hybridization analyses of 19 C. jejuni isolates recovered from chickens and humans worldwide over the past 20 years were performed to determine the distribution of a subset of differentially identified gene sequences.

The immunobiology of cholangiocytes

Cholangiocytes, the epithelial cells lining bile ducts, provide the first line of defense against lumenal microbes in the biliary system. Recent advances in biliary immunity indicate that cholangiocytes express a variety of pathogen-recognition receptors and can activate a set of intracellular signaling cascades to initiate a profound antimicrobial defense, including release of proinflammatory cytokines and chemokines, production of antimicrobial peptides and maintenance of biliary epithelial integrity. Cholangiocytes also interact with other cell types in the liver (for example, lymphocytes and Kupffer cells) through expression and release of adhesion molecules and immune mediators. Subsequently, through an intricate feedback mechanism involving both epithelial and other liver cells, a set of intracellular signaling pathways are activated to regulate the functional state of cholangiocyte responses during microbial infection. Thus, cholangiocytes are actively involved in mucosal immunity of the biliary system and represent a fine-tuned, integral component of liver immunity.

Helicobacter species are associated with possible increase in risk of biliary lithiasis and benign biliary diseases

Background

Hepato-biliary tract lithiasis is common and present either as pain or as asymptomatic on abdominal ultrasonography for other causes. Although the DNA of Helicobacter species are identified in the gallbladder bile, tissue or stones analyzed from these cases, still a causal relationship could not be established due to different results from different geographical parts.

Methods

A detailed search of pubmed and pubmedcentral was carried out with key words Helicobacter and gallbladder, gallstones, hepaticolithiasis, cholelithiasis and choledocholithiasis, benign biliary diseases, liver diseases. The data was entered in a data base and meta analysis was carried out. The analysis was carried out using odds ratio and a fixed effect model, 95% confidence intervals for odds ratio was calculated. Chi square test for heterogeneity was employed. The overall effect was calculated using Z test.

Results

A total of 12 articles were identified. One study used IgG for diagnosis while others used the PCR for Ure A gene, 16 S RNA or Cag A genes. A couple of studies used culture or histopathology besides the PCR. The cumulative results show a higher association of Helicobacter with chronic liver diseases (30.48%), and stone diseases (42.96%)(OR 1.77 95% CI 1.2–2.58; Z = 2.94, p = 0.003), the effect of each could not be identified as it was difficult to isolate the effect of helicobacter due to mixing of cases in each study.

Conclusion

The results of present meta analysis shows that there is a slight higher risk of cholelithiasis and benign liver disease (OR 1.77), however due to inherent inability to isolate the effect of stone disease from that of other benign lesions it is not possible to say for sure that Helicobacter has a casual relationship with benign biliary disease or stone disease or both.

Interferon gamma accelerates NF-kappaB activation of biliary epithelial cells induced by Toll-like receptor and ligand interaction

BACKGROUND

The Toll-like receptor (TLR) family recognises pathogen associated molecular patterns (PAMPs) and plays a pivotal role in the innate immune response. Biliary epithelial cells (BECs) lining the intrahepatic bile ducts are potentially exposed to bacterial components in bile, and murine BECs possess TLRs that recognise PAMPs, resulting in nuclear factor kappaB (NF-kappaB) activation.

AIMS

To examine the presence of TLRs in human BECs and the influence of cytokines and PAMPs on TLR expression and NF-kappaB activation.

METHODS

The expression of TLR2-5, MD-2, MyD88, and IRAK1 was examined in human liver tissue and cultured BECs by immunohistochemistry or reverse transcription polymerase chain reaction. The influence of PAMPs (peptidoglycan and lipopolysaccharide) in cultured cells preincubated with interferon gamma (IFNgamma) was evaluated by NF-kappaB activation.

RESULTS

TLR2-5, MyD88, and IRAK-1 proteins were detectable in BECs of the intrahepatic biliary tree in human liver tissue. TLR2-5, MD-2, MyD88, and IRAK-1 mRNA was demonstrated in human cultured BECs. The expression of these TLRs was upregulated by IFNgamma, and TLR2 was upregulated by tumour necrosis factor alpha. Interleukins 4 and 6 failed to induce TLR upregulation. Interestingly, preincubation with IFNgamma synergistically increased the upregulation of NF-kappaB induced by PAMPs in cultured BECs.

CONCLUSION

These results suggest that the TLR family is present in human biliary cells and participates in the innate immunity of the intrahepatic biliary tree. Disordered regulation of TLRs after intracellular signalling by cytokines and PAMPs may be involved in immune mediated biliary diseases.

Helicobacter pylori and other Helicobacter species in gallbladder and liver of patients with chronic cholecystitis detected by immunological and molecular methods

OBJECTIVE

Despite several recent reports on the detection of Helicobacter DNA in human bile, there are still uncertainties concerning the correlation of these findings with biliary tract and liver diseases.

MATERIAL AND METHODS

Using molecular methods and immunohistochemistry (IHC), we investigated gallbladder and liver biopsy specimens from 22 adult Ukrainian patients with chronic cholecystitis for the presence of Helicobacter species. Patient sera were collected and tested for antibody reactivity to antigens of three Helicobacter spp. Detection of Helicobacter DNA was performed using a Helicobacter genus-specific 16S rDNA PCR. Amplified DNA was identified by PCR-denaturating gradient gel electrophoresis (DGGE) and DNA sequencing. Tissue sections of gallbladder and liver were examined by IHC with antibodies specific to H. pylori, the CagA and VacA cytotoxins of H. pylori, H. hepaticus and to Campylobacter jejuni. Patient sera were analysed by immunoblot for IgG antibodies to soluble surface proteins of H. pylori, H. hepaticus and H. bilis.

RESULTS

Helicobacter DNA was found in 16/22 (73%) of the gallbladder samples and in 11/22 (50%) of the liver samples. IHC showed the presence of the H. pylori specific cytotoxins CagA and VacA inside the gallbladder epithelial cells without co-localization of H. pylori at the epithelial lining. Immunoblot analysis of the patient sera did not show any correlation between the presence of Helicobacter DNA and IgG antibody responses.

CONCLUSIONS

The high prevalence of Helicobacter DNA and the positive findings by IHC in gallbladder and liver raise questions concerning an infectious role of Helicobacter in patients with chronic cholecystitis.

Peptide antibiotic human beta-defensin-1 and -2 contribute to antimicrobial defense of the intrahepatic biliary tree

Human beta-defensins (hBDs) are important antimicrobial peptides that contribute to innate immunity at mucosal surfaces. This study was undertaken to investigate the expression of hBD-1 and hBD-2 in intrahepatic biliary epithelial cells in specimens of human liver, and 4 cultured cell lines (2 consisting of biliary epithelial cells and 2 cholangiocarcinoma cells). In addition, hBD-1 and hBD-2 were assayed in specimens of bile. hBD-1 was nonspecifically expressed immunohistochemically in intrahepatic biliary epithelium and hepatocytes in all patients studied, but expression of hBD-2 was restricted to large intrahepatic bile ducts in 8 of 10 patients with extrahepatic biliary obstruction (EBO), 7 of 11 with hepatolithiasis, 1 of 6 with primary biliary cirrhosis (PBC), 1 of 5 with primary sclerosing cholangitis (PSC), 0 of 6 with chronic hepatitis C (CH-C), and 0 of 11 with normal hepatic histology. hBD-2 expression was evident in bile ducts exhibiting active inflammation. Serum C reactive protein levels correlated with biliary epithelial expression of hBD-2. Real-time PCR revealed that in all of 28 specimens of fresh liver, including specimens from patients with hepatolithiasis, PBC, PSC, CH-C and normal hepatic histology, hBD-1 messenger RNA was consistently expressed, whereas hBD-2 messenger RNA was selectively expressed in biliary epithelium of patients with hepatolithiasis. Immunobloting analysis revealed hBD-2 protein in bile in 1 of 3 patients with PSC, 1 of 3 with PBC, and each of 6 with hepatolithiasis; in contrast, hBD-1 was detectable in all bile samples examined. Four cultured biliary epithelial cell lines consistently expressed hBD-1; in contrast these cell lines did not express hBD-2 spontaneously but were induced to express hBD-2 by treatment with Eschericia coli, lipopolysaccharide, interleukin-1beta or tumor necrosis factor-alpha. In conclusion, these findings suggest that in the intrahepatic biliary tree, hBD-2 is expressed in response to local infection and/or active inflammation, whereas hBD-1 may constitute a preexisting component of the biliary antimicrobial defense system.

Association of the presence of Helicobacter in gallbladder tissue with cholelithiasis and cholecystitis

The presence of Helicobacter DNA species has been investigated in the biliary epithelium of patients with biliary diseases. However, conflicting results have been observed that may have been due to the small number of subjects studied, difficulty in obtaining a healthy control group, absence of controlling for confounding factors, or differences among populations. Therefore, we investigated the presence of Helicobacter species by culture and nested PCR of 16S rRNA genes in gallbladder tissue and bile from 46 Brazilian subjects with and 18 without cholelithiasis. The control group was mainly composed of liver donors and of patients who had submitted to cholecystectomy as part of the surgical treatment for morbid obesity. No Helicobacter species were grown from the bile or gallbladder tissues. Helicobacter DNA was detected in the gallbladder tissue and bile from 31.3 and 42.9% of the patients, respectively. In a logistic regression model, cholelithiasis was positively and independently associated with the female gender (P = 0.02), increasing age (P = 0.002), and the presence of Helicobacter DNA in the gallbladder tissue (P = 0.009). The presence of Helicobacter DNA in the bile was not associated with cholelithiasis (P = 0.8). A significant association between the presence of Helicobacter DNA in the gallbladder epithelium and histological cholecystitis, even after adjusting for gender and age (P = 0.002), was also observed. The sequences of the 16S rRNA genes were >99% similar to that of Helicobacter pylori. In conclusion, our results support the hypothesis that Helicobacter is associated with the pathogenesis of human cholelithiasis and cholecystitis.

Extragastric Helicobacter species

The genus Helicobacter has expanded at a rapid pace and no fewer than 31 species have been named since the proposal of the genus in 1989. Of these 31 species, 22 are principally associated with extragastric niches and there is increasing interest in the role of these taxa in diseases of humans and animals. Substantial evidence attests to certain species playing a role in the pathogenesis of enteric, hepatic and biliary disorders and some taxa demonstrate zoonotic potential. The importance of extragastric Helicobacters is likely to be an important topic for research in the near future. Here, important papers published in the field this last year are reviewed.

Review article: Helicobacter species and hepatobiliary diseases

Helicobacter species, which may colonize the biliary tract, have been implicated as a possible cause of hepatobiliary diseases ranging from chronic cholecystitis and primary sclerosing cholangitis to gall-bladder carcinoma and primary hepatic carcinomas. Research in this area has been limited by the lack of a gold standard in the diagnosis of these organisms in bile. Most published data to date have been based on molecular techniques that detect the DNA of Helicobacter species in bile, rather than evidence of viable organisms in bile. Helicobacter species have not been shown to induce histological injury to the biliary epithelium or liver parenchyma. The strongest association of the presence of these organisms in bile is with cholestatic conditions. This article reviews the literature on this newly developing field as it has evolved historically, taking pertinent methodological issues into account.

The role of microorganisms in biliary tract disease

The biliary tract is normally sterile, but bile-tolerant bacteria are frequently isolated from patients with cholecystitis. Since the identification of about 25 Helicobacter species, some of which may grow in bile, studies have addressed the role of these organisms in primary biliary cirrhosis, primary sclerosing cholangitis, and cholelithiasis. Most of these bacteria show the presence of Helicobacter DNA or antigens in the bile tract and in liver samples. Altogether, data from studies on biliary and hepatic diseases, as well as pancreatic disorders, suggest that bile-tolerant Helicobacter species may induce a chronic infection with possible malignant transformation.

Hepatobiliary inflammation, neoplasia, and argyrophilic bacteria in a ferret colony

Hepatobiliary disease was diagnosed in eight of 34 genetically unrelated cohabitating pet ferrets (Mustela putorios furo) during a 7-year period. The eight ferrets ranged in age from 5 to 8 years and exhibited chronic cholangiohepatitis coupled with cellular proliferation ranging from hyperplasia to frank neoplasia. Spiral-shaped argyrophilic bacteria were demonstrated in livers of three ferrets, including two with carcinoma. Sequence analysis of a 400-base pair polymerase chain reaction product amplified from DNA derived from fecal bacteria from one ferret demonstrated 98% and 97% similarity to Helicobacter cholecystus and Helicobacter sp. strain 266-1 , respectively. The clustering of severe hepatic disease in these cohabitating ferroes suggests a possible infectious etiology. The role of Helicobacter species and other bacteria in hepatitis and/or neoplasia in ferrets requires further study.

Campylobacter infection: small bowel and colon

The important contribution of Campylobacter infections to human enteric disease is well established. Recent completion of the genomic sequence of a Campylobacter jejuni strain has heralded a renaissance in the field of Campylobacter pathogenesis research. With the application of novel, powerful technologies, our understanding of how these organisms mediate disease is set to evolve rapidly from its current, relatively neglected status.