Immune dysfunction in patients with obstructive jaundice before and after endoscopic retrograde cholangiopancreatography

Neutrophil extracellular traps induce intrahepatic thrombotic tendency and liver damage in cholestatic liver disease

BACKGROUND

Cholestatic liver diseases induce local and systemic hypercoagulation, with neutrophil extracellular traps (NETs) serving as major drivers. These NETs have been linked to decreased liver function in patients with obstructive jaundice. However, the impact of NETs on liver hypercoagulation in cholestatic liver disease remains unknown.

METHODS

We utilized bile duct ligation to create experimental mice and analyzed NETs formation in the liver. Fibrin deposition, tissue factor expression, and inflammation in the liver were visualized through western blot and immunohistochemical techniques. LSECs were incubated with isolated NETs, and we detected endothelial procoagulant activity using coagulation protein production assays and measuring endothelial permeability. In both in vivo and in vitro settings, DNase I was applied to clarify the effect of NETs on intrahepatic hypercoagulability, hepatotoxicity, LSEC, and macrophage activation or injury.

RESULTS

Bile duct ligation mice exhibited significantly increased levels of NETs in liver tissue, accompanied by neutrophil infiltration, tissue necrosis, fibrin deposition, and thrombophilia compared to sham mice. Notably, NETs resulted in phosphatidylserine and tissue factor exposure on LSEC, enhancing coagulation Factor Xa and thrombin production. The enhanced procoagulant activity could be reversed by degrading NETs with DNase I. Additionally, NETs-induced permeability changes in LSECs, characterized by increased VE-cadherin expression and F-actin retraction, which could be rescued by DNase I. Meanwhile, NET formation is associated with KC activation and the formation of inflammatory factors.

CONCLUSIONS

NETs promote intrahepatic activation of coagulation and inflammation, leading to liver tissue injury. Strategies targeting NET formation may offer a potential therapeutic approach for treating cholestatic liver disease.

Cannabinoid Receptor-2 Activation in Keratinocytes Contributes to Elevated Peripheral β-Endorphin Levels in Patients With Obstructive Jaundice

BACKGROUND

Cholestatic diseases are often accompanied by elevated plasma levels of endogenous opioid peptides, but it is still unclear whether central or peripheral mechanisms are involved in this process, and little is known about the change of pain threshold in these patients. The purpose of this study was to determine the preoperative pain threshold, postoperative morphine consumption, and central and peripheral β-endorphin levels in patients with obstructive jaundice. This study also tests the hypothesis that activation of the cannabinoid receptor-2 (CB2R) in skin keratinocytes by endocannabinoids is the mechanism underlying circulating β-endorphin elevation in patients with obstructive jaundice.

METHODS

The electrical pain thresholds, 48-hour postoperative morphine consumption, concentrations of β-endorphin in plasma and cerebrospinal fluid, skin and liver β-endorphin expression, and plasma levels of endocannabinoids were measured in jaundiced (n = 32) and control (n = 32) patients. Male Sprague-Dawley rats and human keratinocytes (human immortalized keratinocyte cell line [HaCaT]) were used for the in vivo and in vitro experiments, respectively. Mechanical and thermal withdrawal latency, plasma level, and skin expression of β-endorphin were measured in CB2R-antagonist-treated and control bile duct-ligated (BDL) rats. In cultured keratinocytes, the effect of CB2R agonist AM1241-induced β-endorphin expression was observed and the phosphorylation of extracellular-regulated protein kinases 1/2, p38, and signal transducer and activator of transcription (STAT) pathways were investigated.

RESULTS

This study found (1) the plasma level of β-endorphin (mean ± standard error of the mean [SEM]) was 193.9 ± 9.6 pg/mL in control patients, while it was significantly increased in jaundiced patients (286.6 ± 14.5 pg/mL); (2) the electrical pain perception threshold and the electrical pain tolerance threshold were higher in patients with obstructive jaundice compared with controls, while the 48-hour postoperative morphine consumption was lower in the jaundiced patients; (3) there was no correlation between plasma β-endorphin levels, electrical pain thresholds, and 48-hour postoperative morphine consumption in patients with obstructive jaundice; (4) the plasma level of the endogenous cannabinoid anandamide was increased in the jaundiced patients; (5) CB2R antagonist treatment of the BDL rats reduced β-endorphin levels in plasma and skin keratinocytes, while it did not alter the nociceptive thresholds in BDL and control rats; (6) the endocannabinoid anandamide-induced β-endorphin synthesis and release via CB2R in cultured keratinocytes; and (7) phosphorylation of extracellular-regulated protein kinases 1/2 is involved in the CB2R-agonist-induced β-endorphin expression in keratinocytes.

CONCLUSIONS

CB2R activation in keratinocytes by the endocannabinoid anandamide may play an important role in the peripheral elevation of β-endorphin during obstructive jaundice.

Neutrophil extracellular traps enhance procoagulant activity and thrombotic tendency in patients with obstructive jaundice

BACKGROUND & AIMS

Patients with obstructive jaundice (OJ) are considered to be prothrombotic with increased risk of thromboembolism complications. The role of neutrophil extracellular traps (NETs) in procoagulant activity (PCA) and thrombosis risk in patients with OJ is unclear. In this study, we investigated NETs formation in OJ patients and the role of elevated unconjugated bilirubin (UCB) in inducing NETs, resulting in enhanced PCA and endothelial injury.

METHODS

NETs of OJ patients and healthy controls were measured. NETs PCA was assessed via coagulation time (CT), fibrin formation and purified coagulation complex production assays. Visualization of NETs and mitochondrial reactive oxygen species (MitoROS) were performed with a fluorescence microscope. We further used confocal microscopy to quantify the exposure of phosphatidylserine (PS), fibrin strands and FVa/Xa on Human umbilical vein endothelial cells (HUVECs).

RESULTS

Assessment of NETs components levels revealed greater NETs production in OJ patients than in healthy controls. Importantly, OJ-NETs were responsible for enhanced PCA. UCB induced NETs formation via MitoROS accumulation and mitochondrial mobilization. HUVECs cocultured with OJ NETs lost their cell-cell junctions and consequently converted to a procoagulant phenotype. The PCA was attenuated by using DNase I alone or in combination with lactadherin.

CONCLUSIONS

Our results suggest that UCB-induced NETs play a prominent role in promoting the hypercoagulable and prothrombotic state in OJ patients. The increased MitoROS accumulation in neutrophils initiated NETosis. NETs are promising targets for indicating or improving coagulation disorders in OJ patients.

Preoperative Endoscopic Biliary Stenting Before Pancreaticoduodenectomy: Does Timing Matter?

Background. The role of preoperative biliary stenting (PBS) before pancreaticoduodenectomy (PD) in patients with obstructive jaundice is debatable. The objective of the current study was to assess PD outcomes after upfront surgery or PBS and determine the impact of stent to surgery duration on PD outcomes. Methods. We reviewed patients who underwent PD between 2011 and 2019. Patients were grouped based on whether they underwent upfront surgery (n = 67) or PBS (n = 66). We further assessed outcomes based on stent to surgery duration. Results. There was no significant difference in 30-day mortality (3% vs. 2.9%, P = 1), 90-day mortality (7.5% vs. 4.4%, P = .4), and Grade B-C pancreatic fistula rates (7.5% vs. 4.4%, P = .4) in the PBS and upfront surgery groups, respectively. A significant increase in wound infections (22.7% vs. 7.4%, P = .01) and readmissions (10.6% vs. 0, P = .006) was seen in the PBS group. The highest rate of wound infection was seen when stent to surgery duration was 4-6 weeks (41.6%). The wound infection rates in the upfront surgery group, high-risk PBS group (4-6 weeks), and low-risk PBS group were 5/67(7.4%), 5/12(41.6%), and 7/36(19.4%), respectively (P = .008). Conclusions. PBS increases postoperative wound infections when compared with upfront surgery. Patients operated between 4 and 6 weeks after stenting have the highest rate of wound infection.

Does Pre-operative Biliary Drainage Influence Long-Term Survival in Patients With Obstructive Jaundice With Resectable Pancreatic Head Cancer?

Objectives: Whether pre-operative biliary drainage (PBD) affects long-term survival of patients with obstructive jaundice with pancreatic ductal adenocarcinoma (PDAC) who underwent pancreaticoduodenectomy is still controversial. Most of the previous research did not include the important total serum bilirubin (TB) level before intervention as well as before surgery. The aim of this study is to evaluate the impact of PBD on long-term survival after considering the TB level.

Methods: Data were collected retrospectively from patients with obstructive jaundice who underwent resection of pancreatic head cancer in a high-volume center. X-Tile software and Kaplan-Meier survival analysis were applied to determine the optimal cut-off levels for TB and age based on the minimal probability (P)-value and the largest χ2-value. Multivariate Cox regression analyses were performed after univariate analysis to assess independent prognostic factors for overall survival (OS) and disease-free survival (DFS).

Results: Of 426 patients with obstructive jaundice who underwent pancreaticoduodenectomy for resectable pancreatic head cancer during a 7 year period, 242 (56.8%) received PBD and 184 (43.2%) underwent surgery directly. The OS of patients who received PBD was significantly worse than that of patients who did not receive PBD by univariate analysis (median of 16.6 vs. 22.2 months, P = 0.048). After including liver function parameters in the multivariate Cox regression, we found that the use of PBD was not associated with OS or DFS, while TB before intervention >150 μmol/L was an independent adverse prognostic factor for both OS [hazard ratio (HR), 1.42; 95% CI, 1.05–1.91] and DFS (HR, 1.38; 95% CI, 1.08–1.77).

Conclusions: In patients with obstructive jaundice with resectable pancreatic head cancer, undergoing PBD before pancreaticoduodenectomy did not impair or benefit survival rates compared with surgery alone. However, TB before intervention >150 μmol/L predicted an unfavorable prognosis, irrespective of the PBD procedure.

Internal biliary drainage superior to external biliary drainage in improving gut mucosa barrier because of goblet cells and mucin-2 up-regulation

Backgroud: Obstructive jaundice increases intestinal permeability, but the pathological mechanisms remain obscure, which results in debates about the necessity of performing preoperative biliary drainage in patients with obstructive jaundice. Mucin-2 (MUC2) and goblet cells regulated by bile acids play an important role in maintaining the function of intestinal mucosal barrier. The present study was to investigate the role of goblet cells and MUC2 in obstructive jaundice and evaluate the effect of biliary drainage on intestinal permeability.

STUDY DESIGN

We enrolled patients with malignant biliary obstruction and controls. We also did animal studies with four groups of rats: sham operation, obstructive jaundice, internal biliary drainage, and external biliary drainage. Histopathological analysis, biochemical measurement, and electron microscopy examination were done on pertinent samples.

RESULTS

Compared with the control group, the small intestinal mucosa was significantly damaged; goblet cells and MUC2 were significantly decreased and serum endotoxin level was significantly increased in patients and rats with obstructive jaundice. Biliary drainage, especially internal biliary drainage, significantly increased goblet cells and MUC2 and attenuated the damage of small intestinal mucosa.

CONCLUSIONS

In obstructive jaundice condition, goblet cells and MUC2 were reduced which were involved in the damage of intestinal mucosa barrier; biliary drainage increased goblet cells and MUC2, repaired mucosa layer and restored the intestinal mucosa barrier function.

Bile and circulating HMGB1 contributes to systemic inflammation in obstructive jaundice

BACKGROUND

Obstructive jaundice (OJ) patients with cholangitis are prone to sepsis; however, the underlying mechanisms are still not clear and need to be clarified.

METHODS

Analyzing all available published data related to the title of this article.

RESULTS

OJ leads to absence of gut luminal bile and accumulation of hepatic and circulating bile acids. Absence of gut luminal bile deprives the gut from its antiinflammatory, endotoxin-binding, bacteriostatic, mucosal-trophic, epithelial tight-junction maintaining, and gut motility-regulating effects, leading to gut bacterial overgrowth, mucosal atrophy, mucosal tight-junction loss, and gut motility dysfunction. These alterations promote intestinal endotoxin and bacterial translocation (BT) into portal and systemic circulation. Gut BT triggers systemic inflammation, which can lead to multiple organ dysfunctions in OJ. The accumulation of hepatic and circulating bile acids kills/damages hepatocyte and Kupffer cells, and it also significantly decreases the number of liver natural killer T-cells in OJ. This results in impaired hepatic and systemic immune function, which facilitates BT. In addition, neutralizing bile HMGB1 can reverse endotoxemic bile-induced gut BT and mucosal injury in mice, suggesting that bile HMGB1 in OJ patients can be responsible for internal drainage-related clinical complications. Moreover, the elevated circulating HMGB1 level may contribute to multiple organ injuries, and it might also mediate gut BT in OJ.

CONCLUSIONS

HMGB1 may significantly contribute to systemic inflammation and multiple organ dysfunctions in OJ.

Pathophysiological consequences of obstructive jaundice and perioperative management

BACKGROUND

Obstructive jaundice is a common problem in daily clinical practice. Understanding completely the pathophysiological changes in obstructive jaundice remains a challenge for planning current and future management.

DATA SOURCES

A PubMed was searched for relevant articles published up to August 2016. The effect of obstructive jaundice on proinflammatory cytokines, coagulation status, hemodynamics and organ functions were evaluated.

RESULTS

The effects of obstructive jaundice included biliary tree, the hepatic cell and liver function as well as systemic complications. The lack of bile in the gut, the disruption of the intestinal mucosal barrier, the increased absorption of endotoxin and the subsequent endotoxemia cause proinflammatory cytokine production (TNF-α, IL-6). Bilirubin induces systemic inflammatory response syndrome which may lead to multiple organ dysfunction syndrome. The principal clinical manifestations include hemodynamic instability and acute renal failure, cardiovascular suppression, immune compromise, coagulation disorders, nutritional impairment, and wound healing defect. The proper management includes full replacement of water and electrolyte deficiency, prophylactic antibiotics, lactulose, vitamin K and fresh frozen plasma, albumin and dopamine. The preoperative biliary drainage has not been indicated in overall, but only in a few selected cases.

CONCLUSION

The perioperative management is an essential measure in improving the outcome after the appropriate surgical operation in jaundiced patients especially those with malignancy.

Reprogramming of pro-inflammatory human macrophages to an anti-inflammatory phenotype by bile acids

Cholestasis is caused by autoimmune reactions, drug-induced hepatotoxicity, viral infections of the liver and the obstruction of bile ducts by tumours or gallstones. Cholestatic conditions are associated with impaired innate and adaptive immunity, including alterations of the cellular functions of monocytes, macrophages, NK cells and T-cells. Bile acids act as signalling molecules, affecting lipopolysaccharide (LPS)-induced cytokine expression in primary human macrophages. The present manuscript investigates the impact of bile acids, such as taurolithocholic acid (TLC), on the transcriptome of human macrophages in the presence or absence of LPS. While TLC itself has almost no effect on gene expression under control conditions, this compound modulates the expression of 202 out of 865 transcripts in the presence of LPS. Interestingly, pathway analysis revealed that TLC specifically supressed the expression of genes involved in mediating pro-inflammatory effects, phagocytosis, interactions with pathogens and autophagy as well as the recruitment of immune cells, such as NK cells, neutrophils and T cells. These data indicate a broad influence of bile acids on inflammatory responses and immune functions in macrophages. These findings may contribute to the clinical observation that patients with cholestasis present a lack of response to bacterial or viral infections.