Reticulo-endothelial function in rats with obstructive jaundice

Association of preoperative cholangitis with outcomes and expenditures among patients undergoing pancreaticoduodenectomy

BACKGROUND

This study aimed to characterize the association of preoperative acute cholangitis (PAC) with surgical outcomes and healthcare costs.

METHODS

Patients who underwent pancreaticoduodenectomy (PD) between 2013 and 2021 were identified using 100% Medicare Standard Analytic Files. PAC was defined as the occurrence of at least 1 episode of acute cholangitis within the year preceding surgery. Multivariable regression analyses were used to compare postoperative outcomes and costs relative to PAC.

RESULTS

Among 23,455 Medicare beneficiaries who underwent PD, 2,217 patients (9.5%) had at least 1 episode of PAC. Most patients (n = 14,729 [62.8%]) underwent PD for a malignant indication. On multivariable analyses, PAC was associated with elevated odds of surgical site infection (odds ratio [OR], 1.14; 95% CI, 1.01-1.29), sepsis (OR, 1.17; 95% CI, 1.01-1.37), extended length of stay (OR, 1.13; 95% CI, 1.01-1.26), and readmission within 90 days (OR, 1.14; 95% CI, 1.04-1.26). Patients with a history of PAC before PD had a reduced likelihood of achieving a postoperative textbook outcome (OR, 0.83; 95% CI, 0.75-0.92) along with 87.8% and 18.4% higher associated preoperative and postoperative healthcare costs, respectively (all P < .001). Overall costs increased substantially among patients with more than 1 PAC episode ($59,893 [95% CI, $57,827-$61,959] for no episode vs $77,922 [95% CI, $73,854-$81,990] for 1 episode vs $101,205 [95% CI, $94,871-$107,539] for multiple episodes).

CONCLUSION

Approximately 1 in 10 patients undergoing PD experienced an antecedent PAC episode, which was associated with adverse surgical outcomes and greater healthcare expenditures.

Bacterial culture and immunohistochemical detection of bacteria and endotoxin in cats with suppurative cholangitis-cholangiohepatitis syndrome

OBJECTIVE

To characterize the frequency and type of bacterial infection by culture- and immunohistochemical (IHC)-based methods and determine the impact of infection on clinical features and survival time in cats with suppurative cholangitis-cholangiohepatitis syndrome (S-CCHS).

ANIMALS

168 client-owned cats with S-CCHS (cases).

PROCEDURES

Clinical features, bacterial culture results, culture-inoculate sources, and survival details were recorded. Cases were subcategorized by comorbidity (extrahepatic bile duct obstruction, cholelithiasis, cholecystitis, ductal plate malformation, biopsy-confirmed inflammatory bowel disease, and biopsy-confirmed pancreatitis) or treatment by cholecystectomy or cholecystoenterostomy. Culture results, bacterial isolates, Gram-stain characteristics, and IHC staining were compared among comorbidities. Lipoteichoic acid IHC staining detected gram-positive bacterial cell wall components, and toll-like receptor expression IHC reflected pathologic endotoxin (gram-negative bacteria) exposure.

RESULTS

Clinical features were similar among cases except for more frequent abdominal pain and lethargy in cats with positive culture results and pyrexia, abdominal pain, and hepatomegaly for cats with polymicrobial infections. Bacteria were cultured in 93 of 135 (69%) cats, with common isolates including Enterococcus spp and Escherichia coli. IHC staining was positive in 142 of 151 (94%) cats (lipoteichoic acid, 107/142 [75%]; toll-like receptor 4, 99/142 [70%]). With in-parallel interpretation of culture and IHC-based bacterial detection, 154 of 166 (93%) cats had bacterial infections (gram-positive, 118/154 [77%]; gram-negative, 111/154 [72%]; polymicrobial, 79/154 [51%]). Greater frequency of bacterial isolation occurred with combined tissue, bile, and crushed cholelith inoculates. Infection and gram-positive bacterial isolates were associated with significantly shorter long-term survival times.

CLINICAL RELEVANCE

S-CCHS was associated with bacterial infection, pathologic endotoxin exposure, and frequent polymicrobial infection in cats. Combined tissue inoculates improved culture detection of associated bacteria.

Single versus double experimental bile duct ligation model for inducing bacterial translocation

BACKGROUND

Double common bile duct ligation plus section in rats is used as a model for bacterial translocation, a phenomenon that has been correlated with the degree of liver damage. This study analyzes whether a simpler variant of the technique is also a valid model to study bacterial translocation.

METHODS

Fifty-six male Sprague Dawley rats underwent one of three surgical interventions: a) proximal double ligation and section of the common bile duct; b) proximal simple ligation of the bile duct; and c) sham operation. Bacterial translocation was measured by cultures of mesenteric lymph nodes, blood, spleen and liver. Stool culture and histological analysis of liver damage were also performed.

RESULTS

The incidence of bacterial translocation in SBL and DBDL groups was 23,5% and 25% respectively. Mortality was similar between ligation groups (11.2% versus 10%). Liver cirrhosis developed in the group of double ligation and section (100% of the animals at 4 weeks), while portal hypertension appeared starting at week 3. None of the animals submitted to simple ligation developed liver cirrhosis.

CONCLUSIONS

Simple bile duct ligation is associated with a similar incidence of bacterial translocation as double ligation, but without cirrhosis or portal hypertension.

Should preoperative biliary drainage be routinely performed for obstructive jaundice with resectable tumor?

Obstructive jaundice is a common clinical manifestation of malignant lesions adjacent to extrahepatic bile duct, ampulla or pancreatic head. Animal experiments and some clinical observations have demonstrated that preoperative biliary drainage could improve liver function as well as reduce endotoxemia, thereby reducing the incidence of perioperative complications. However, a number of randomized, controlled studies have found that preoperative biliary drainage failed to improve prognosis or reduce the incidence of perioperative complications; in contrast, it might increase the incidence of complications and cause extra financial burden on patients. Thus, whether preoperative biliary drainage should be performed or not is controversial. Since clinical randomized controlled studies are more relevant in clinical setting, we believe that preoperative biliary drainage should not be routinely performed for obstructive jaundice with resectable tumors. More randomized, controlled, prospective studies should be conducted for further exploration.

The quandary of preresection biliary drainage for pancreatic cancer

Surgery in patients with obstructive jaundice caused by a tumor in the pancreatic head area is associated with a higher risk of postoperative complications. Preoperative biliary drainage was introduced in an attempt to improve the general condition and reduce morbidity and mortality. Extensive experimental studies have been performed to analyze the beneficial effect of biliary drainage and showed improvement in liver function, nutritional status, and cell-mediated immune function as well as reduction in mortality. However, despite the results seen in the experimental studies, clinical studies reported both beneficial and adverse effects, and most studies advised against routinely performing preoperative biliary drainage. To add clarity to the ongoing controversy, a recent randomized controlled trial was performed and reported more overall complications in patients with jaundice who underwent preoperative biliary drainage followed by surgery compared to those who underwent surgery alone. Many of these complications were stent related. Like most clinical studies, a plastic stent was used to initiate biliary drainage. Patients with jaundice because of a tumor in the pancreatic head area without locoregional irresectability or metastases should be candidates for early surgery. Preoperative biliary drainage should not be performed routinely. However, some selected patients might benefit from preoperative biliary drainage, in cases of severe jaundice, neoadjuvant therapy, or postponed surgery due to logistics. In these cases, the use of metal biliary stents is indicated.

Preoperative biliary drainage in patients with obstructive jaundice: history and current status

RATIONALE

Preoperative biliary drainage (PBD) has been introduced to improve outcome after surgery in patients suffering from obstructive jaundice due to a potentially resectable proximal or distal bile duct/pancreatic head lesion. In experimental models, PBD is almost exclusively associated with beneficial results: improved liver function and nutritional status; reduction of systemic endotoxemia; cytokine release; and, as a result, an improved immune response. Mortality was significantly reduced in these animal models. Human studies show conflicting results.

FINDINGS

For distal obstruction, currently the "best-evidence" available clearly shows that routine PBD does not yield the appreciated improvement in postoperative morbidity and mortality in patients undergoing resection. Moreover, PBD harbors its own complications. However, most of the available data are outdated or suffer from methodological deficits.

CONCLUSION

The highest level of evidence for PBD to be performed in proximal obstruction, as well as over the preferred mode, is lacking but, nevertheless, assimilated in the treatment algorithm for many centers. Logistics and waiting lists, although sometimes inevitable, could be factors that might influence the decision to opt for PBD, as well as an extended diagnostic workup with laparoscopy (on indication) or scheduled preoperative chemotherapy.

Pulmonary phagocyte depression induced by an acid or alkaline solution in a rat model of peritonitis

BACKGROUND

Peritonitis is a surgical problem with a high mortality rate attributable to various complications, including respiratory infection. This complication is more common under certain conditions reflective of the origin of peritonitis, suggesting that the composition of the peritoneal fluid exerts an influence on the intensity of the macrophage and peritoneal response. To establish a correlation among macrophage function, absorption of bacteria from the peritoneal cavity, and the pH of the peritoneal fluid, we carried out this study.

METHODS

Thirty female Wistar rats were divided into three equal groups, all of which received infusions of 0.9% saline by parietal puncture. In group A (control), the saline pH was 7.0; in group B, it was 2.5; and in group C, it was 8.5. After 40 min, 0.25 mL of a suspension containing 10(11) colony-forming units of (99m)Tc-labeled Escherichia coli was infused by the same route. After another 40 min, samples of vena caval blood, spleen, liver, and lung were removed; the radioactivity was counted; bacterial absorption was determined; and the proportional radioactivity/g of tissue was calculated. The values were compared among the groups by the Student t-test, with the level of significance set at p < 0.05.

RESULTS

There was significantly greater bacterial absorption in group B than in group C (p = 0.004) but no differences in the numbers of bacteria in the liver and spleen. Bacteria were significantly more numerous in the peripheral blood in group B than in groups A and C (p = 0.04 for both). Pulmonary phagocytosis was significantly reduced in group B compared with group A (p = 0.008) and group C (p = 0.005).

CONCLUSION

Peritonitis associated with acidic conditions in the peritoneal cavity is correlated with a reduction in pulmonary phagocytosis and an increase in the numbers of nonphagocytized bacteria in the peripheral blood, possibly representing a direct or indirect cause of the higher incidence of pneumonia and sepsis in these individuals.

Altered Kupffer cell function in biliary obstruction

BACKGROUND

An altered Kupffer cell (KC) response is thought to be responsible for the characteristic phenotype observed after biliary obstruction: a phenotype marked by a defect in the hepatic reticuloendothelial system and a hypersensitivity to endotoxin. Few studies, however, have directly examined KC function. We have sought to define the specific alterations in function and phenotype that occur in the KC after biliary obstruction.

METHODS

KCs were isolated from female C57BL/6 mice 4 days after a sham or common bile duct ligation (CBDL) operation. Phagocytosis, oxidative burst potential, and intracellular bacterial killing were measured as markers of reticuloendothelial system function. The KC response to endotoxin was assessed by measuring tumor necrosis factor alpha and interleukin 6 levels in the media after stimulation with lipopolysaccharide (LPS) or with LPS plus LPS-binding protein (LBP).

RESULTS

CBDL KCs demonstrated a significant increase in phagocytic ability and significantly decreased baseline oxidative stress, compared with Shams. The oxidative burst potential, however, was equivalent or higher for CBDL KCs. CBDL KCs also demonstrated increased numbers of viable intracellular bacteria after infection; however, it is unclear if this finding represents impaired intracellular bacterial killing or increased phagocytosis of bacteria. With respect to the KC response to endotoxin, CBDL KCs were found to be less sensitive to the stimulatory effects of LPS alone but were exquisitely sensitive to the effects of LBP. LBP levels were found to be significantly elevated in CBDL animals, and CBDL KCs demonstrated a dose-dependent, exaggerated tumor necrosis factor alpha and interleukin 6 response to LPS administered with LBP.

CONCLUSIONS

KC function is clearly altered after biliary obstruction. Phagocytic ability is actually increased, although the ability of CBDL KCs to kill bacteria within the phagosome remains ill defined. CBDL KCs are exquisitely sensitive to the effects of LBP, and LBP levels are elevated after biliary obstruction. LBP may be responsible for the increased proinflammatory response observed after endotoxin challenge in animals with biliary obstruction.

Endotoxin challenge causes a proinflammatory state in obstructive jaundice

The aim of this study was to investigate the relationship between the obstructive jaundice-induced cellular immune suppression and endotoxin challenge with respect to the levels of tumor necrosis factor (TNF), interleukin-10 (IL-10), and interleukin-2 (IL-2). Rats underwent either bile duct ligation or sham operation. At 21 days, all rats were challenged either with lipopolysaccharide (LPS) or saline. In the sham-operated group LPS injection significantly increased TNF levels at 90 min. The common bile duct ligated group showed a significant increase in TNF levels compared with all other groups, including the sham-operated, LPS-injected group, at 90 min. At 180 min following LPS challenge, TNF levels decreased, and there was no difference between any of the LPS-challenged groups at 180 min and any of the saline groups at either 90 or 180 min. In the sham-operated group, LPS injection significantly increased IL-10 levels at both 90 and 180 min. In the bile duct ligated group, LPS injection significantly increased IL-10 levels compared with saline injection at both 90 and 180 min. On the other hand, bile duct ligated animals had significantly less increase in IL-10 levels following LPS challenge at 90 min but not at 180 min. In common bile duct ligated rats, LPS challenge induced a significantly greater increase in IL-2 levels compared with all other groups. In conclusion, in the presence of obstructive jaundice, endotoxemia primes a more vigorous inflammatory response despite cellular immune depression.

Alterations of tumor necrosis factor-alpha and interleukin 6 production and activity of the reticuloendothelial system in experimental obstructive jaundice in rats

BACKGROUND

Immunological changes are well recognised in obstructive jaundice. The aim of this study was to monitor plasma tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) levels in rats with obstructive jaundice.

METHODS

The ability of splenocytes and peritoneal exudate cells (PEC) to produce these cytokines both spontaneously and on induction with lipopolysaccharide (LPS), was compared in rats with and without obstructive jaundice (OJ). The activity of the reticuloendothelial system (RES) was also measured.

RESULTS

Serum cytokine levels in OJ rats were higher than in control rats. PEC cultures produced significantly more IL-6, compared with control rats, declining thereafter. TNF-alpha activity in the splenocyte cultures of OJ rats was also higher than in the control group. Pronounced differences were found in the ability to produce TNF-alpha by PEC, i.e., TNF-alpha production was much stronger on day 7 in OJ rats than in controls. On day 14 TNF-alpha production was much lower and the spontaneous response was equal to the LPS-induced one. On day 21 the cells of OJ rats partially regained the ability to produce TNF-alpha RES activity of OJ rats was significantly suppressed in the liver and spleen, whereas the phagocytic activity in the lungs was elevated.

CONCLUSION

We have demonstrated that the immune reactivity of OJ rats, initially elevated, underwent subsequent depression. The study also revealed a major effect of the operation alone on the studied parameters.

Translocação de bactérias marcadas com Tc99 na icterícia obstrutiva em ratos

Estudo realizado com o objetivo de avaliar a translocação bacteriana (TB) do tubo gastrointestinal para órgãos viscerais na icterícia obstrutiva. Quatro grupos de ratos foram estudados: grupo I (n=10) ligadura do colédoco, grupo II (n=10) controle ou "sham operation", grupo III (n=12) ligadura do colédoco e gavagem com 99mTc-Escherichia coli e grupo IV (n=5) controle ou "sham operation" e gavagem com 99mTc-E.coli. Usando técnica asséptica e sob anestesia com pentobarbital sódico (20mg/kg), os animais foram submetidos à laparotomia e nos ratos dos grupos I e III foi realizada ligadura do colédoco com fio de seda nº 000. Nos ratos dos grupos II e IV foi feita apenas a manipulação do colédoco com pinça de Adison. Após sete dias, os animais dos grupos I e II foram mortos e ressecados fígado, baço, linfonodos mesentéricos e pulmões para exame microbiológico (meios Agar-sangue e Agar Mac Conkey) e exame histopatológico (coloração H.E. e Tricrômico de Masson) por análise morfométrica. Nos animais dos grupos III e IV, após sete dias, foi administrada por via oral (gavagem) 99mTc-E.coli e após 24h, os ratos de ambos os grupos foram mortos e seus órgãos retirados para contagem da radioatividade em cintilador automático Gama, modelo ANSR (ABBOT). O nível médio de bilirrubina, nos grupos ictéricos, foi significantemente maior do que o do grupo controle. O estudo microbiológico revelou maior incidência de bactérias translocadas no grupo I, comparada ao controle (p< 0,05). Os resultados não mostraram diferença significante na captação da 99mTc-E.coli entre os dois grupos. Porém, a análise das interações grupo x órgão mostrou diferença entre os grupos ictérico e controle para os órgãos: fígado e pulmão. Os dados permitem concluir que em ratos ictéricos por ligadura do colédoco ocorreu TB detectável por exame microbiológico. Não ocorreu TB com 99mTc-E. coli no modelo proposto.

Acute (ascending) cholangitis

Cholangitis is an infection of an obstructed biliary system, most commonly due to common bile duct stones. Bacteria reach the biliary system either by ascent from the intestine or by the portal venous system. Once the biliary system is colonized, biliary stasis allows bacterial multiplication, and increased biliary pressures enable the bacteria to penetrate cellular barriers and enter the bloodstream. Patients with cholangitis are febrile, often have abdominal pain, and are jaundiced. A minority of patients present in shock with hypotension and altered mentation. There is usually a leukocytosis, and the alkaline phosphatase and bilirubin levels are generally elevated. Noninvasive diagnostic techniques include sonography, which is the recommended initial imaging modality. Standard CT, helical CT cholangiography, and magnetic resonance cholangiography often add important information regarding the type and level of obstruction. Endoscopic sonography is a more invasive means of obtaining high-quality imaging, and endoscopic or percutaneous cholangiography offers the opportunity to perform a therapeutic procedure at the time of diagnostic imaging. Endoscopic modalities currently are favored over percutaneous procedures because of a lower risk of complication. Treatment includes fluid resuscitation and antimicrobial agents that cover enteric flora. Biliary decompression is required when patients do not rapidly respond to conservative therapy. Definitive therapy can be performed by a surgical, percutaneous, or endoscopic route; the last is favored because it is the least invasive and has the lowest complication rate. Overall prognosis depends on the severity of the illness at the time of presentation and the cause of the biliary obstruction.

Impaired Kupffer cell function and effect of immunotherapy in obstructive jaundice

BACKGROUND

Obstructive jaundice is frequently associated with septic complications. This study examined the influence of biliary obstruction on bacterial clearance and translocation. The study focused on the phagocytic and killing activities of Kupffer cells and the preventive effect on bacterial translocation of OK-432, which is a hemolytic streptococcal preparation developed as a biological response modifier.

METHODS

To study the mechanism of sepsis in obstructive jaundice, two groups of Wistar rats were examined: rats subjected to common bile duct ligation (CBDL) and rats subjected to a sham operation. Bacterial clearance, organ distribution, hepatic blood flow, and phagocytic function of Kupffer cells were examined. To evaluate the effect of OK-432 on bacterial translocation, rats were divided into three groups: sham operation + phosphate-buffered saline (PBS), CBDL + PBS, and CBDL + OK-432.

RESULTS

In this study, clearance of Escherichia coli. from the peripheral blood in CBDL rats was decreased significantly compared with that in sham-operated rats. Significant decreases in E.coli trapped in the liver and in hepatic blood flow were observed in CBDL rats compared with sham-operated rats. Phagocytic activity and superoxide production of Kupffer cells isolated from CBDL rats were significantly lower than in sham-operated rats. The incidence of bacterial translocation in CBDL rats was increased significantly, and oral administration of OK-432 prevented it.

CONCLUSION

The results suggest that susceptibility to infection in obstructive jaundice is due to impaired phagocytic function of Kupffer cells. Furthermore, obstructive jaundice promotes bacterial translocation, and OK-432 may be useful in preventing this translocation.

Renal effects of experimental obstructive jaundice: morphological and functional assessment

BACKGROUND

The pathophysiology of renal impairments occurring in obstructive jaundice has been extensively studied, but the underlying mechanism of these derangements remains unclear. The aim of the present study was to investigate the time-related morphological and functional changes occurring in the kidneys of rats undergoing obstructive jaundice.

METHODS

Histological examination, renal function assessment and determination of (Na + K)-ATPase activity were performed in the kidneys of rats 7, 14, and 21 days following bile duct ligation (BDL) or sham operation (sham).

RESULTS

Glomerular filtration rate was unaffected by BDL throughout the period of the study. Tubular effects occurred at days 7 and 14, being more marked at day 7, and consisted of an increase of about twice in the fractional excretion of sodium and chloride, paralleled by a decreased proximal and distal tubular reabsorption of sodium of about 50 and 40%, respectively. Natriuresis was consistent with augmentation of osmolar clearance but it was not associated with changes in the activity of renal (Na+ + K+)-ATPase. The ability to dilute urine was impaired at days 14 and 21 after BDL. Additionally, these effects were accompanied by decreased tubulointerstitial fibrosis and vasodilation of inner medullary capillaries. At day 21, the parameters of tubular function in BDL and sham groups were not significantly different.

CONCLUSIONS

These data support the view that raised natriuresis taking place in the initial 2 weeks following BDL is due mainly to tubular effects. The contribution of hemodynamic, paracrine and humoral mediators is discussed.

Characterization of the Kupffer cell response to exogenous endotoxin in a rodent model of obstructive jaundice

BACKGROUND

Sepsis and endotoxaemia occur frequently in biliary obstruction. Impaired Kupffer cell endocytosis is implicated in these events. Tumour necrosis factor and interleukin 6, secreted by Kupffer cells, are important mediators of sepsis. Kupffer cell clearance of endotoxin and secretion of cytokines in experimental obstructive jaundice were investigated.

METHODS

Wistar rats were randomized to bile duct ligation, sham operation or control. Groups (n = 8) were studied 1 and 3 weeks after operation. Kupffer cell function was assessed using in situ hepatic perfusion.

RESULTS

Clearance of endotoxin was significantly depressed 1 week (median (interquartile range) 20.3 (10.5-27.1) per cent) and 3 weeks (22.1 (20.2-23.2) per cent) after bile duct ligation compared with that in respective sham animals (35.5 (29.9-41.6) and 40.9 (37.7-47.0) per cent) and controls (39.5 (37.3-46.8) per cent). Secretion of tumour necrosis factor was significantly greater 1 week (1113.7 (706.5-1436. 8) pg/ml) and 3 weeks (1118.2 (775.7-1484.1) pg/ml) following bile duct ligation compared with that in respective sham animals (114.3 (0-178.5) and 107.6 (63.7-166.4) pg/ml) and controls (0 (0-20.7) pg/ml). Interleukin 6 was not secreted by sham or control animals but was present in the perfusate from jaundiced animals at 1 and 3 weeks (52.5 (9.9-89.5) and 66.2 (60.2-193.1) pg/ml).

CONCLUSION

These data demonstrate simultaneous impairment of Kupffer cell clearance of endotoxin and increased secretion of proinflammatory cytokines in experimental obstructive jaundice. These diverse responses may contribute to the development of sepsis-related complications in biliary obstruction.

Reversible Kupffer cell suppression in biliary obstruction is caused by hydrophobic bile acids

BACKGROUND/AIM

Biliary obstruction is associated with suppressed Kupffer cell clearance of bacteria and intracellular bactericidal activity of the phagocytes. We studied the superoxide generation of Kupffer cell in biliary obstruction and after incubation with bile acids to elucidate the mechanism of impaired intracellular killing of these phagocytes.

METHODS

Kupffer cells were extracted from rats with common bile duct ligation or sham-operation. The extracted cells were tested for superoxide production immediately after extraction, 2 h and 24 h post-extraction. Superoxide generation from Kupffer cells after incubation with five bile acids (cholic acid, taurocholic acid, deoxycholic acid, chenodeoxycholic acid and ursodeoxycholic acid) at two different concentrations (0.1 mM and 1.0 mM) were also studied. Cell viability was monitored by trypan blue exclusion.

RESULTS

Kupffer cells extracted from common duct-ligated animals had significantly lower superoxide production (-1.37+/-0.24 nmol O2(-)/10(6) cells) compared to that from sham-operated rats (2.54+/-0.58 nmol O2(-)/10(6) cells) and non-operated rats (2.15+/-0.76 nmol O2(-)/10(6) cells) (p<0.05). After 2 h of resting in culture medium, these cells recovered significantly in superoxide production to 2.72+/-0.63 nmol O2(-)/10(6) cells (p<0.01). A dose-related reduction in superoxide production was demonstrated when Kupffer cells were incubated with bile acids. Hydrophobic bile acids (deoxycholic acid and chenodeoxycholic acid) caused more significant suppression than with hydrophilic bile acids (cholic acid, taurocholic acid, ursodeoxycholic acid). The drop in superoxide production after bile acid treatment was not due to cell death. Washing in Hank's balanced salt solution resulted in partial recovery of Kupffer cell superoxide production.

CONCLUSION

High blood levels of hydrophobic bile acids are likely to be the cause of impaired intracellular bactericidal activity of Kupffer cells in biliary obstruction.

Protective effect of the intravenous administration of ursodeoxycholic acid against endotoxemia in rats with obstructive jaundice

This study was undertaken to elucidate the effect of the intravenous administration of ursodeoxycholic acid (UDCA) on endotoxemia in rats with obstructive jaundice from the viewpoint of the biliary excretion of lipopolysaccharide (LPS) through hepatocytes. In rats with obstructive jaundice, fluorescein isothiocyanate-labeled LPS was administered via the portal vein and then its biliary excretion was examined. A significant increase in the LPS excretion was thus noticed in UDCA-treated rats at a dose of 0.1 micromol/100 g body wt. per min. In place of UDCA, sodium taurocholate at the same dose also enhanced the biliary excretion of LPS. Secondly, we also examined whether or not UDCA protects against endotoxemia. In this experiment, nonlabeled LPS was administered via the portal vein and its peripheral concentration was then measured. In UDCA-treated rats, the endotoxin concentration was significantly lower. Finally, to elucidate the effect of UDCA on Kupffer cells, serum tumor necrosis factor (TNF-alpha) was measured. But UDCA had no effect on the TNF-alpha level. These findings thus demonstrate that the intravenous administration of UDCA protects against endotoxemia by enhancing the transport of LPS across the hepatocytes from blood to bile without affecting Kupffer cells, and that this biliary excretion of LPS is dependent on bile acids.

Does level of ligation influence results in a murine biliary obstruction model?

BACKGROUND

Despite advances in perioperative management, patients with extrahepatic biliary obstruction still experience a high rate of complications and death after surgery. The rat is commonly used as an experimental animal for research in obstructive jaundice. Ligation of the rat bile duct high in the liver hilum is assumed to produce a more severe model of biliary obstruction than low ligation. The differences are attributed to the ability of the rat bile duct to dilate. Differences in level of ligation may, thus, explain some discrepancies between studies.

MATERIALS AND METHODS

To test this hypothesis, female Lewis rats underwent high ligation (HL), low ligation (LL), and sham celiotomy. Colloidal carbon clearance, bilirubin, total serum bile acids, and hematocrit were measured 12 days later. Liver and spleen weight, presence or absence of ascites, infection, and adequacy of ligation were noted and the liver was processed for routine histology and electron microscopy.

RESULTS

Although bilirubin levels were higher after HL than after LL, liver and spleen weight, total serum bile salts, and phagocytic constants K and alpha were not different between these two groups. Gross, histologic, and ultrastructural appearance did not differ between HL and LL groups.

CONCLUSION

High ligation causes greater hyperbilirubinemia than low ligation, but does not alter other parameters including phagocytic constants. The present study does not confirm the hypothesis that HL creates a more severe model than LL; therefore, it is unlikely that differences in level of ligation explain variability in results between studies.

T lymphocyte function in patients with malignant biliary obstruction

The T lymphocyte function in 59 patients with malignant biliary obstruction undergoing pre-operative endoscopic drainage (group Ia, n = 24) or surgery (group Ib, n = 35) was evaluated by mitogen stimulation test with phytohaemagglutinin. The T lymphocyte function before endoscopic or surgical intervention was found to be impaired as compared with patients with gastric cancer (group II, n = 27) and with normal persons (group III, n = 19). Regression analysis showed a significant negative correlation between T lymphocyte function and the serum bilirubin level (correlation coefficient -0.3, P = 0.01) and a positive correlation with serum albumin level (correlation coefficient 0.34, P = 0.01) and serum transferrin level (correlation coefficient 0.45, P = 0.001). After 18 +/- 3 days of endoscopic biliary drainage, the T lymphocyte function of group Ia patients did not change substantially. At postoperative day 14, there were more patients in both groups Ia and Ib having deterioration of T lymphocyte function than those with improvement. The incidence of postoperative sepsis was found to be significantly higher in patients with deterioration than those with improvement of T lymphocyte function (18/31 vs 7/26, P = 0.036). It is concluded that endoscopic biliary drainage and surgery could not reverse the T lymphocyte dysfunction in patients with malignant biliary obstruction.

Postoperative immunological function and jaundice

The effects of operative trauma and obstructive jaundice on systemic immunity were studied in a rat model, using the delayed-type hypersensitivity response to 2,4-dinitro-1-fluorobenzene as a measure of systemic immune responsiveness. Midline laparotomy caused a significant decrease in the mean(s.e.m.) delayed-type hypersensitivity response 1 week after operation (4.6(1.3) versus 19.0(2.2) per cent for controls). The response returned to control levels by 2 weeks (14.6(3.1) per cent). Common bile duct ligation and division resulted in a significantly depressed hypersensitivity response at 2 and 3 weeks (6.8(2.0) and 8.4(1.6) per cent respectively). The expected decrease in the response at 1 week in these animals was not observed (mean(s.e.m.) 12.7(2.7) per cent), suggesting a possible role for the normal liver in the induction of postoperative immune depression. Impaired function of the reticuloendothelial system was induced in non-jaundiced animals by Kupffer cell ablation following intraportal infusion of lambda-carrageenan. A similar prevention of postoperative immune hyporesponsiveness was observed (mean(s.e.m.) 10.4(1.0) versus 10.4(1.6) per cent for controls). Hepatic Kupffer cells play an important role in the induction of postoperative immune depression.

Modification of reticuloendothelial function by muramyl dipeptide-encapsulated liposomes in jaundiced rats treated with biliary decompression

Rats with 2 weeks of biliary obstruction, with and without 1 week of concomitant biliary decompression relieving the jaundice, were treated with physiologic saline, free muramyl dipeptide (MDP), placebo liposomes, or liposome-encapsulated MDP. Reticuloendothelial system (RES) function was evaluated by blood clearance of intravenously injected 125I-labelled Escherichia coli. The corrected phagocytic index (alpha) after 1 week of biliary decompression returned to normal levels in animals treated with MDP liposomes, whereas RES function was impaired (P < 0.05) in all other jaundiced and biliary-decompressed groups. In the biliary-decompressed, MDP-liposome-treated group, hepatic uptake of radiolabelled bacteria was significantly higher (P < 0.05) and renal entrapment of bacteria was significantly lower (P < 0.05) than in all other jaundiced and biliary-decompressed groups. We conclude that treatment with MDP liposomes improves the otherwise impaired RES function in rats with biliary obstruction and biliary decompression.

Effect of biliary decompression on reticuloendothelial function in jaundiced rats

The recovery of reticuloendothelial system (RES) function following decompression of obstructive jaundice was studied using a rat model with bile duct ligation and side-to-side choledochoduodenostomy. Histopathological changes in the liver were still present 5 weeks after relief of jaundice, while results of liver function tests had returned to normal. RES function evaluated by the blood clearance and organ uptake of radiolabelled Escherichia coli using a corrected phagocytic index gradually returned to normal following biliary decompression. The severely impaired RES activity noted 1 week after operation may explain the increased incidence of sepsis and renal insufficiency in the early period after biliary surgery in jaundiced patients.

Body water compartments in patients with obstructive jaundice

To elucidate the pathogenesis of renal dysfunction associated with obstructive jaundice, body water compartments were measured using a multi-isotope dilution technique in ten patients with biliary tract obstruction and in ten control subjects matched for age, sex, weight, height and body surface area. Expressed as a fraction of body-weight, total body water was reduced in jaundiced patients (41.8 versus 46.2 per cent, P less than 0.02). Extracellular water volume was also reduced in patients with jaundice (20.3 versus 24.3 per cent, P less than 0.003) owing to a reduction of the interstitial space (16.1 versus 19.5 per cent, P less than 0.004) and, to a lesser degree, of the plasma volume (4.2 versus 4.8 per cent, P = 0.1). There was a close correlation in jaundiced patients between plasma volume and the creatinine clearance rate (r2 = 0.56, P less than 0.02) and between plasma volume and extracellular volume (r2 = 0.77, P less than 0.0001). Extracellular volume in such patients also correlated with the percentage weight loss (r2 = 0.42, P = 0.04). Obstructive jaundice is associated with a contracted extracellular water compartment, although extracellular water, as a percentage of body-weight, increased in proportion to the body-weight lost. Reduction of the interstitial volume and a marginally reduced plasma volume may be determinant factors in the pathogenesis of the renal and haemodynamic disturbances observed in patients with biliary tract obstruction.

Defense system in the biliary tract against bacterial infection

Bacteria can invade the biliary tract by ascending from the duodenum and via the hematogenous route from the hepatic portal venous blood. The sphincter of Oddi, situated at the junction of the biliary tract and the upper gastrointestinal tract, forms an effective mechanical barrier to duodenal reflex and ascending bacterial infection. Conversely, Kupffer cells and the tight junctions between hepatocytes help prevent bacteria and toxic metabolites from entering the hepatobiliary system from the portal circulation. The continuous flushing action of bile and the bacteriostatic effects of bile salts keeps the biliary tract sterile under normal conditions. Secretory immunoglobulin A (sIgA), the predominant immunoglobulin in the bile, and mucus excreted by the biliary epithelium probably function as antiadherence factors, preventing microbial colonization. When barrier mechanisms break down, as in surgical or endoscopic sphincterotomy and with insertion of biliary stents, pathogenic bacteria enter the biliary system at high concentrations and take up residence on any foreign bodies. Intrabiliary pressure is a key factor in the development of cholangitis. Chronic biliary obstruction raises the intrabiliary pressure. This adversely influences the defensive mechanisms such as the tight junctions, Kupffer cell functions, bile flow, and sIgA production in the system, resulting in a higher incidence of septicemia and endotoxemia in these patients. Knowledge of biliary defense against infection is still quite primitive. Unclear are the roles of sIgA in the bile, mechanism of bacterial adhesion to the biliary epithelium, Kupffer cell function in biliary obstruction, and the antimicrobial activity of bile salts.

Endotoxin-induced lung hemorrhages in obstructive jaundiced rats

Endotoxemia in patients with biliary obstruction contributes to the high morbidity and mortality rates following surgery. We developed an animal model of disseminated intravascular coagulation (DIC) in rats on which bile duct ligation was performed following an injection of endotoxin (200 micrograms/kg bw). Macroscopic hemorrhages and microthrombi in the lung were found in jaundiced rats 6 hours after the injection of endotoxin and yet these phenomena were not found in non-jaundiced rats following an injection of the same amount of endotoxin. Coagulation studies also revealed characteristic findings of DIC in the jaundiced rats following the injection of endotoxin. This study confirms that obstructive jaundice is one of the main predisposing factors in the course of endotoxin-induced DIC.

The role of bile acids in the development of endotoxemia during obstructive jaundice in the rat

The role of bile acids in the development of endotoxemia during obstructive jaundice was studied in rats. Endotoxin was not found in portal and peripheral plasma of control rats. The bile ducts of seven rats were ligated. On day 7 following bile duct ligation, six animals showed portal endotoxemia and five peripheral. Oral administration of sodium ursodeoxycholate reduced this frequency to 1/7 for portal plasma and 0/7 in the case of peripheral plasma. Subsequently the influence of a bile salt mixture (85% taurocholate, 15% taurodeoxycholate) on the binding and uptake of Salmonella abortus equi lipopolysaccharide by cultured rat Kupffer cells was studied. In control preparations, the percentage cell-associated lipopolysaccharide increased with time and reached a plateau after about 2 h of incubation at 37 degrees C. In the presence of 0.3, 0.6 and 1 mumol bile salts/ml the cell-associated lipopolysaccharide was about 5%, 13% and 29% lower, respectively, of that in control cultures. Tauroursodeoxycholate (1 mM) did not inhibit the lipopolysaccharide uptake by cultured rat Kupffer cells. Based on these observations, it is likely that both phenomena, i.e., (a) the low amount of bile acids in the intestines and (b) the high serum bile acid level, account for the high frequency of endotoxemia in the peripheral blood during obstructive jaundice.

Effects of long-chain triglyceride emulsions on reticuloendothelial system function in humans

Parenteral administration of long-chain triglyceride emulsions has been shown to have deleterious effects on reticuloendothelial system function in animal models. It is unknown whether this interference occurs in humans with clinically relevant doses of intravenous fat. Two studies were done. Eighteen patients were prospectively enrolled for study. Patients received full feeding by continuous total parenteral nutrition (amino acids 1.5 g/kg/day and dextrose 4.5 g/kg/day) with 33.1 kcal/kg/day. Forty-three % of the nonprotein calories were provided as soybean oil emulsion (Travamulsion 20%) and was administered intravenously over 10 hr (0.130 g/kg/hr). Reticuloendothelial system function was determined by measuring the change in the clearance rate of intravenously injected 99mTc-sulfur colloid (TSC) in each patient. In study 1 (n = 10), one day of lipid (10 hr) was infused, with the clearance of 99mTc-sulfur colloid measured before the lipid was infused and then during the last hour of the 10-hr infusion. In study 2 (n = 8), the clearance rates were measured before the lipid emulsion was begun, and then during the last hour of the infusion on the 3rd day. Clearance rates for TSC after 10 hr of lipid infusion in study 1 did not differ (0.27 +/- 1/min to 0.26 +/- 0.1/min, p greater than 0.10). However, after 3 days of lipid infusion (10 hr/day), a statistically significant reduction in TSC was seen (0.46 +/- 0.08/min-0.27 +/- 0.03/min, p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The role of bile acids in the reduction in lipopolysaccharide uptake by cultured rat Kupffer cells

The influence of bile salts on the binding and uptake of Salmonella abortus equi lipopolysaccharide by cultured Kupffer cells was studied. In control preparations, the percentage of cell-associated lipopolysaccharide increased with time and reached a plateau after about 2 h incubation at 37 degrees C. About 1.2 micrograms lipopolysaccharide was associated with 10(6) Kupffer cells at this time interval. In the presence of 0.3, 0.6 and 1 mumol bile salts/ml the cell-associated lipopolysaccharide was respectively, about 5%, 13% and 29% lower than in control cultures. In the presence of 1 mumol bile salts/ml, the association of lipopolysaccharide to cells at 0 degrees C was about 25% lower than in controls. Preincubation of Kupffer cells with 1 mumol bile salts/ml, with or without lipopolysaccharide, did not affect cell-associated lipopolysaccharide after removal of the bile salts. The rate of secretion of radioactivity by Kupffer cells was not influenced by the presence of bile salts during the uptake or the secretion periods. Bile acids proved to inactivate lipopolysaccharide. From these observations it was concluded that low concentrations of bile salts influence the binding and uptake of lipopolysaccharide by Kupffer cells. It was, therefore, considered likely that, in patients with obstructive jaundice, the high serum bile acid level accounts for spill-over of portal lipopolysaccharide into the systemic blood.

Risk of biliary surgery in patients with hyperbilirubinemia

Previous studies have suggested a direct relationship between the serum bilirubin level and the risk of operation. However, patients with high bilirubin levels are usually older and have associated conditions unrelated to jaundice that may contribute to the development of postoperative complications. We studied the courses of 98 consecutive patients who were admitted with biliary obstruction and a serum bilirubin level of 10 mg/dl or greater and underwent operation. Sixty-one had neoplastic obstructions, 26 had benign biliary strictures, 8 had choledocholithiasis, and 3 had other obstructive lesions. Comorbid factors were evaluated and assigned a score to reflect their severity. Neither age nor advanced local cancer was considered to be a comorbid factor. Biliary obstruction was treated by resection of the bile duct, the pancreas, or both in 28 patients, by bilioenteric bypass in 55 patients, and by other operations in 15 patients. Postoperatively, complications developed in 30 patients and 8 died. There was no correlation between the admission serum bilirubin level, hematocrit value, or serum albumin level and the development of complications or death. There was a strong correlation between the presence of severe associated disease and the risk of postoperative complications or death. Nineteen of 81 patients with a comorbid score below 4 had a complication compared with 11 of 17 patients with scores of 4 or higher (p less than 0.01). Two of the 81 patients with scores below 4 died compared with 6 of 17 patients with a score of 4 or higher. These findings show that postoperative deaths and serious complications in patients with severe jaundice are principally the result of uncontrolled associated disease and that jaundice per se does not contribute substantially to an undesirable outcome.