Perioperative or adjuvant mFOLFIRINOX for resectable pancreatic cancer (PREOPANC-3): study protocol for a multicenter randomized controlled trial.

BACKGROUND: Surgical resection followed by adjuvant mFOLFIRINOX (5-fluorouracil with leucovorin, irinotecan, and oxaliplatin) is currently the standard of care for patients with resectable pancreatic cancer. The main concern regarding adjuvant chemotherapy is that only half of patients actually receive adjuvant treatment. Neoadjuvant chemotherapy, on the other hand, guarantees early systemic treatment and may increase chemotherapy use and thereby improve overall survival. Furthermore, it may prevent futile surgery in patients with rapidly progressive disease. However, some argue that neoadjuvant therapy delays surgery, which could lead to progression towards unresectable disease and thus offset the potential benefits. Comparison of perioperative (i.e., neoadjuvant and adjuvant) with (only) adjuvant administration of mFOLFIRINOX in a randomized controlled trial (RCT) is needed to determine the optimal approach. METHODS: This multicenter, phase 3, RCT will include 378 patients with resectable pancreatic ductal adenocarcinoma with a WHO performance status of 0 or 1. Patients are recruited from 20 Dutch centers and three centers in Norway and Sweden. Resectable pancreatic cancer is defined as no arterial contact and ≤ 90 degrees venous contact. Patients in the intervention arm are scheduled for 8 cycles of neoadjuvant mFOLFIRINOX followed by surgery and 4 cycles of adjuvant mFOLFIRINOX (2-week cycle of oxaliplatin 85 mg/m2, leucovorin 400 mg/m2, irinotecan 150 mg/m2 at day 1, followed by 46 h continuous infusion of 5-fluorouracil 2400 g/m2). Patients in the comparator arm start with surgery followed by 12 cycles of adjuvant mFOLFIRINOX. The primary outcome is overall survival by intention-to-treat. Secondary outcomes include progression-free survival, resection rate, quality of life, adverse events, and surgical complications. To detect a hazard ratio of 0.70 with 80% power, 252 events are needed. The number of events is expected to be reached after the inclusion of 378 patients in 36 months, with analysis planned 18 months after the last patient has been randomized. DISCUSSION: The multicenter PREOPANC-3 trial compares perioperative mFOLFIRINOX with adjuvant mFOLFIRINOX in patients with resectable pancreatic cancer. TRIAL REGISTRATION: Clinical Trials: NCT04927780. Registered June 16, 2021.

Centralizing a national pancreatoduodenectomy service: striking the right balance.

BACKGROUND: Centralization of pancreatic surgery is currently called for owing to superior outcomes in higher-volume centres. Conversely, organizational and patient concerns speak for a moderation in centralization. Consensus on the optimal balance has not yet been reached. This observational study presents a volume-outcome analysis of a complete national cohort in a health system with long-standing centralization. METHODS: Data for all pancreatoduodenectomies in Norway in 2015 and 2016 were identified through a national quality registry and completed through electronic patient journals. Hospitals were dichotomized (high-volume (40 or more procedures/year) or medium-low-volume). RESULTS: Some 394 procedures were performed (201 in high-volume and 193 in medium-low-volume units). Major postoperative complications occurred in 125 patients (31·7 per cent). A clinically relevant postoperative pancreatic fistula occurred in 66 patients (16·8 per cent). Some 17 patients (4·3 per cent) died within 90 days, and the failure-to-rescue rate was 13·6 per cent (17 of 125 patients). In multivariable comparison with the high-volume centre, medium-low-volume units had similar overall complication rates, lower 90-day mortality (odds ratio 0·24, 95 per cent c.i. 0·07 to 0·82) and no tendency for a higher failure-to-rescue rate. CONCLUSION: Centralization beyond medium volume will probably not improve on 90-day mortality or failure-to-rescue rates after pancreatoduodenectomy.

ANTECEDENTES: Actualmente se aboga por la centralización de la cirugía pancreática debido a los mejores resultados obtenidos en los centros de mayor volumen. Por el contrario, la preocupación de las organizaciones y de los pacientes está en línea con la sobriedad en la centralización. Todavía no se ha alcanzado un consenso en el equilibrio óptimo. Este estudio observacional presenta un análisis de volumen-resultado de una cohorte nacional completa en un sistema de salud con largo tiempo de centralización. MÉTODOS: Se identificaron los datos de todas las duodenopancreatectomías realizadas en Noruega en 2015 y 2016 a través de un registro nacional de calidad y se completaron a través de los datos electrónicos de los pacientes. Los hospitales fueron dicotomizados (volumen alto (≥ 40 procedimientos/año) o volumen medio/bajo)) RESULTADOS: Se realizaron 394 procedimientos (201 versus 193 en unidades de volumen alto versus volumen medio/bajo). Un total de 125 pacientes (31,7%) presentaron complicaciones postoperatorias mayores. Se diagnosticó una fístula pancreática postoperatoria clínicamente relevante en 66 pacientes (16,8%). En total, 17 pacientes (4,3%) fallecieron dentro de los 90 días, y la tasa de fracaso de rescate fue de 17 de 125 (13,6%) pacientes. En el análisis multivariable de comparación con el centro de volumen alto, las unidades de volumen medio/bajo presentaron tasas de complicaciones generales iguales, menor mortalidad a los 90 días (razón de oportunidades, odds ratio, OR 0,2, i.c. del 95% 0,1-0,8) y sin tendencia a una mayor tasa de fracaso de rescate. CONCLUSIÓN: La centralización más allá del volumen medio probablemente no mejore la mortalidad a los 90 días o las tasas de fracaso de rescate después de la duodenopancreatectomía.

Nasogastric Tube on Demand is Rarely Necessary After Pancreatoduodenectomy Within an Enhanced Recovery Pathway.

BACKGROUND: Evidence-based guidelines for enhanced recovery (ERAS) pathways after pancreatoduodenectomy (PD) are available. Routine use of nasogatric tube (NGT) after PD is not recommended. This study aims to evaluate the need for NGT reinsertion after PD performed within an ERAS setting. METHODS: It is a prospective observational study of all patients undergoing PD in a tertiary referral hospital within the study period from 2015 throughout 2016. Pre- and postoperative variables were collected. Patients requiring NGT reinsertion were identified. Comparative analysis of patients with and without a NGT reinsertion was performed, as well as multivariate analysis for risk factors for on-demand NGT reinsertion. RESULTS: Two-hundred and one patients were included. In total, 45 (22.4%) patients required NGT reinsertion after PD. A total of 32 (15.9%) patients underwent a relaparotomy. Reinsertion of NGT in patients not undergoing a relaparotomy occurred in 26 (15.4%) patients. The presence of a major postoperative complication was a risk factor for reinsertion of NGT, OR 5.27 (2.54-10.94, p = 0.001). Patients with the need for a NGT reinsertion had a higher frequency of major postoperative complications and relaparotomy compared to patients without the need of a NGT reinsertion, 26 (57.8%) versus 32 (20.5%), p < 0.001 and 19 (42.2%) versus 13 (8.3%), p < 0.001, respectively. CONCLUSION: Routine use of NGT after PD is not justified within an ERAS setting. Immediate removal of the NGT after the procedure can be performed safely, and reinsertion on demand is rarely necessary in uncomplicated courses.

Trends in indications, complications and outcomes for venous resection during pancreatoduodenectomy.

BACKGROUND: Pancreatoduodenectomy with superior mesenteric-portal vein resection has become a common procedure in pancreatic surgery. The aim of this study was to compare standard pancreatoduodenectomy with pancreatoduodenectomy plus venous resection at a high-volume centre, and to examine trends in management and outcome over a decade for the latter procedure. METHODS: This retrospective observational study included all patients undergoing pancreatoduodenectomy with or without venous resection at Oslo University Hospital between January 2006 and December 2015. Trends were evaluated by assessing preoperative clinical and radiological characteristics, as well as perioperative outcomes in three time intervals (early, intermediate and late). RESULTS: A total of 784 patients had a pancreatoduodenectomy, of whom 127 (16·2 per cent) underwent venous resection. Venous resection resulted in a longer operating time (median 422 versus 312 min; P = 0·001) and greater estimated blood loss (EBL) (median 700 versus 500 ml; P = 0·004) than standard pancreatoduodenectomy. The rate of severe complications was significantly higher for pancreatoduodenectomy with venous resection (37·0 versus 26·3 per cent; P = 0·014). The overall burden of complications, evaluated using the Comprehensive Complication Index (CCI), did not differ (median score 8·7 versus 8·7; P = 0·175). Trends in venous resection over time showed a significant reduction in EBL (median 1050 versus 375 ml; P = 0·001) and duration of hospital stay (median 14 versus 9 days; P = 0·011) between the early and late periods. However, despite an improvement in the intermediate period, severe complication rates returned to baseline in the late period (18 of 43 versus 9 of 42 versus 20 of 42 patients in early, intermediate and late periods respectively; P = 0·032), as did CCI scores (median 20·9 versus 0 versus 20·9; P = 0·041). CONCLUSION: Despite an initial improvement in severe complications for venous resection during pancreatoduodenectomy, this was not maintained over time. Every fourth patient with venous resection needed relaparotomy, most frequently for bleeding.

Resection of synchronous liver metastases between radiotherapy and definitive surgery for locally advanced rectal cancer: short-term surgical outcomes, overall survival and recurrence-free survival.

AIM: There is debate as to the correct treatment algorithm sequence for patients with locally advanced rectal cancer with liver metastases. The aim of the study was to assess safety, resectability and survival after a modified 'liver-first' approach. METHOD: This was a retrospective study of patients undergoing preoperative radiotherapy for the primary rectal tumour, followed by liver resection and, finally, resection of the primary tumour. Short-term surgical outcome, overall survival and recurrence-free survival are reported. RESULTS: Between 2009 and 2013, 45 patients underwent liver resection after preoperative radiotherapy. Thirty-four patients (76%) received neoadjuvant chemotherapy, 24 (53%) concomitant chemotherapy during radiotherapy and 17 (43%) adjuvant chemotherapy. The median time interval from the last fraction of radiotherapy to liver resection and rectal surgery was 21 (range 7-116) and 60 (range 31-156) days, respectively. Rectal resection was performed in 42 patients but was not performed in one patient with complete response and two with progressive metastatic disease. After rectal surgery three patients did not proceed to a planned second stage liver (n = 2) or lung (n = 1) resection due to progressive disease. Clavien-Dindo ≥Grade III complications developed in 6.7% after liver resection and 19% after rectal resection. The median overall survival and recurrence-free survival in the patients who completed the treatment sequence (n = 40) were 49.7 and 13.0 months, respectively. Twenty of the 30 patients who developed recurrence underwent further treatment with curative intent. CONCLUSION: The modified liver-first approach is safe and efficient in patients with locally advanced rectal cancer and allows initial control of both the primary tumour and the liver metastases.

Differential expression of miRNAs in pancreatobiliary type of periampullary adenocarcinoma and its associated stroma.

Periampullary adenocarcinomas can be of two histological subtypes, intestinal or pancreatobiliary. The latter is more frequent and aggressive, and characterized by a prominent desmoplastic stroma, which is tightly related to the biology of the cancer, including its poor response to chemotherapy. Whereas miRNAs are known to regulate various cellular processes and interactions between cells, their exact role in periampullary carcinoma remains to be characterized, especially with respect to the prominent stromal component of pancreatobiliary type cancers. The present study aimed at elucidating this role by miRNA expression profiling of the carcinomatous and stromal component in twenty periampullary adenocarcinomas of pancreatobiliary type. miRNA expression profiles were compared between carcinoma cells, stromal cells and normal tissue samples. A total of 43 miRNAs were found to be differentially expressed between carcinoma and stroma of which 11 belong to three miRNA families (miR-17, miR-15 and miR-515). The levels of expression of miRNAs miR-17, miR-20a, miR-20b, miR-223, miR-10b, miR-2964a and miR-342 were observed to be higher and miR-519e to be lower in the stromal component compared to the carcinomatous and normal components. They follow a trend where expression in stroma is highest followed by carcinoma and then normal tissue. Pathway analysis revealed that pathways regulating tumor-stroma interactions such as ECM interaction remodeling, epithelial-mesenchymal transition, focal adhesion pathway, TGF-beta, MAPK signaling, axon guidance and endocytosis were differently regulated. The miRNA-mRNA mediated interactions between carcinoma and stromal cells add new knowledge regarding tumor-stroma interactions.

Molecular signatures of mRNAs and miRNAs as prognostic biomarkers in pancreatobiliary and intestinal types of periampullary adenocarcinomas.

Periampullary adenocarcinomas include four anatomical sites of origin (the pancreatic duct, bile duct, ampulla and duodenum) and most of them fall into two histological subgroups (pancreatobiliary and intestinal). Determining the exact origin of the tumor is sometimes difficult, due to overlapping histopathological characteristics. The prognosis depends on the histological subtype, as well as on the anatomical site of origin, the former being the more important. The molecular basis for these differences in prognosis is poorly understood. Whole-genome analyses were used to investigate the association between molecular tumor profiles, pathogenesis and prognosis. A total of 85 periampullary adenocarcinomas were characterized by mRNA and miRNA expressions profiling. Molecular profiles of the tumors from the different anatomical sites of origin as well as of the different histological subtypes were compared. Differentially expressed mRNAs and miRNAs between the two histopathological subtypes were linked to specific molecular pathways. Six miRNA families were downregulated and four were upregulated in the pancreatobiliary type as compared to the intestinal type (P < 0.05). miRNAs and mRNAs associated with improved overall and recurrence free survival for the two histopathological subtypes were identified. For the pancreatobiliary type the genes ATM, PTEN, RB1 and the miRNAs miR-592 and miR-497, and for the intestinal type the genes PDPK1, PIK3R2, G6PC and the miRNAs miR-127-3p, miR-377* were linked to enriched pathways and identified as prognostic markers. The molecular signatures identified may in the future guide the clinicians in the therapeutic decision making to an individualized treatment, if confirmed in other larger datasets.

Follow-up after curative surgery for pancreatic ductal adenocarcinoma: asymptomatic recurrence is associated with improved survival.

AIM: There is no consensus on the optimal follow-up schedule of patients after surgery for pancreatic cancer. In this retrospective study, recurrence and survival were investigated for patients presenting with either symptomatic or asymptomatic recurrence. Patient, tumor and treatment characteristics that predicted the length of postrecurrence survival were identified. METHODS: Clinical records of 164 patients who underwent a pancreatic resection (R0/R1) for pancreatic ductal adenocarcinoma from January 2000 to December 2010 were retrieved. Patients underwent a systematic follow-up program. Patient, tumor and treatment characteristics were compared between patients with asymptomatic and symptomatic recurrence. RESULTS: Of 164 consecutive patients, 144 patients (88%) had recurrence (29 asymptomatic, 115 symptomatic). The most frequent reported symptoms were abdominal pain, fatigue/weakness, back pain, weight loss, nausea/loss of appetite and jaundice. Median time to recurrence was 12.0 months for asymptomatic and 7.0 months for symptomatic patients (P = 0.036). Median postrecurrence survival was 10.0 months for asymptomatic and 4.0 months for symptomatic patients (P < 0.0001). Median overall survival was 24.5 months for asymptomatic and 11.0 months for symptomatic patients (P < 0.0001). Symptomatic recurrence, disease free survival <12 months, and no adjuvant chemotherapy were the only independent predictors of poor postrecurrence survival. 72% of asymptomatic and 37% of symptomatic patients received oncological treatment. CONCLUSIONS: Patients with asymptomatic pancreatic cancer recurrence have improved recurrence-free, postrecurrence and overall survival. Symptoms when recurrence is diagnosed are a good surrogate marker of biological aggressiveness. Detection of asymptomatic recurrence may facilitate patient eligibility for investigational studies or other forms of treatment.

Altered expression of genes in adipose tissues associated with reduced fat mass in patients with pancreatic cancer.

Loss of adipose tissue in patients with pancreatic cancer may involve altered gene expression. Peri-operative mRNA levels of 44 genes were analysed by RT-PCR in intra-abdominal (IAAT) and subcutaneous adipose tissue (SCAT) sampled from pancreatic ductal adenocarcinoma (PDAC) patients undergoing tumour resection (n = 20), and control patients without cancer (n = 11). Peri- and post-operative IAAT and SCAT masses were measured by computerized tomography. PDAC patients displayed 2.6- and 1.7-fold higher Zn-α2-glycoprotein (AZGP1) mRNA levels than controls in IAAT and SCAT, respectively (P < 0.01), but expression was not correlated with post-operative changes in fat masses. IAAT mass changes correlated with genes in lipid metabolism, inflammation and apoptosis: e.g. stearoyl-Coenzyme A desaturase 1 (SCD), tumour necrosis factor (TNF) and chemokine (C-C motif) ligand 2 (CCL2; MCP-1). Patients with PDAC displayed increased AZGP1 mRNA levels in both IAAT and SCAT, but expression of other genes may predict IAAT loss.

Diagnostic approach to the patient with jaundice following trauma.

BACKGROUND AND AIMS: Jaundice in trauma patients may reflect serious underlying pathology. The aim of this review was to determine the appropriate diagnostic approach to the patient with jaundice following trauma. METHODS: A MEDLINE search was performed to retrieve publications which outlined the causes of jaundice in trauma patients. RESULTS: The main causes of jaundice in trauma patients were found to be bilirubin overload caused by breakdown of transfused- and extravasated blood and hepatic dysfunction caused by sepsis, infections, initial shock and systemic hypotension. Bile duct injury or drug induced liver injury are rare. Liver function tests are often uninformative but commonly show a cholestatic pattern. Ultrasound, CT or ERCP are the diagnostic imaging methods most widely used. Abdominal ultrasound and CT may reveal specific organ injuries, bile duct dilatation, intraabdominal fluid collections, hematomas or acalculus cholecystitis. ERCP is often diagnostic and permits a therapeutic intervention when a bile duct injury is present. CONCLUSIONS: The primary aim of the diagnostic approach should be to identify all cases of bile duct injury or obstruction. Sepsis and infections should be actively looked for. The number of blood transfusions must be calculated. Ultrasound, CT or ERCP are the diagnostic imaging methods most widely used.

Aetiology and prognostic implication of severe jaundice in surgical trauma patients.

BACKGROUND: Pronounced postoperative jaundice occurs not infrequently in trauma patients. The aim of this study was to elucidate the implication of early, pronounced jaundice (serum-bilirubin >100 micromol x l(-1)) for 30-day survival of such patients. METHODS: From 1995 through 2001, 53 surgical trauma patients developing pronounced postoperative jaundice were identified. Nine were excluded from the study because of major hepatobiliary injury or pre-existing liver disease. The clinical course and laboratory chemistry profiles of the remaining 44 patients were analysed. RESULTS: Thirty-one patients survived and 13 died within 30 days of trauma. Non-survivors had higher age, higher injury severity score (ISS) and lower probability of survival (PS) (P < 0.05) than survivors. ISS averaged 34 in survivors and 45 in non-survivors. Survivors and non-survivors received a mean of 46 (range 10-97) and 55 units of blood (range 11-128), respectively (P = 0.366). Systemic hypotension, local infections and sepsis were common in both groups. Bilirubin levels peaked around the 11th day in survivors (median 189 micromol x l(-1)). In non-survivors, serum bilirubin values rose progressively, reaching maximum levels at time of death (median 231 micromol x l(-1)). These patients died in a setting of sepsis and multiple organ failure. CONCLUSION: Large endogenous production of bilirubin because of rapid breakdown of transfused and extravasated blood can cause pronounced jaundice in multitransfused trauma patients. In such patients, serum bilirubin rising >100 micromol x l(-1) does not by itself signal poor outcome. However, progressive pronounced jaundice outlasting the trauma incident by 10-12 days portends fatal outcome for the patient.

Cholestatic effect of large bilirubin loads and cholestasis protection conferred by cholic acid co-infusion: a molecular and ultrastructural study.

BACKGROUND: Large intravenous bilirubin loads block biliary phospholipid secretion, produce canalicular membrane lesions and cause canalicular cholestasis. Cholic acid co-infusion forestalls these untoward effects. The aim of this study was first to determine whether bilirubin overload causes cholestasis through reducing the activity or the hepatic expression of the bile salt export pump (bsep) or Na-taurocholate co-transporting polypeptide (ntcp) and, secondly, whether cholic acid co-infusion forestalls cholestasis by upregulating bsep, ntcp or phosphoglycoprotein 3 (pgp3) expressions or activities. A further aim was to determine whether large bilirubin infusions also produce ultrastructural changes inside hepatocytes. METHODS: The effects of intravenous infusion of 2 g bilirubin over 150 min on hepatic expression of bsep, ntcp and pgp3 were studied in bile acid-depleted and cholic acid co-infused pigs, and related to canalicular bile acid transport and bile secretion. Effects on hepatocyte ultrastructural morphology were analysed by electron microscopy. RESULTS: Bilirubin-induced cholestasis reflected marked diminution of bsep and pgp3 transport activities and not reduced hepatic expression of these transporters. Hepatocyte ultrastructural abnormalities were predominantly confined to the hepatocyte canalicular membrane in cholestatic livers. Cholic acid co-infusion with bilirubin conferred complete cholestasis protection through enhancing pgp3 and bsep transporter activities and not through upregulating their expression. Bilirubin infusion did not change ntcp expression. CONCLUSION: Bilirubin-induced cholestasis is due to markedly impaired activity of the membrane-embedded bsep transporter consequent upon ultrastructural injury to the canalicular membrane. Cholic acid co-infusion with bilirubin enhances bsep and pgp3 activities and confers protection against canalicular membrane injury and bilirubin-induced cholestasis.

Intravenous bilirubin, dibromosulfophthalein, and bromosulfophthalein infusions uncouple biliary phospholipid and cholesterol secretion from bile acid secretion by inhibiting hepatic phosphoglycoprotein-3 activity in pigs.

BACKGROUND: Biliary secretion of organic anions disturbs the proportional relationship normally pertaining between biliary lipid and bile acid secretion. The mechanism causing this uncoupling of biliary lipid from bile acid secretion is incompletely understood. Impaired micellization of membrane lipids by bile due to biliary contamination with organic anions or lowering of biliary bile acid concentration by enhanced bile acid-independent bile flow has been proposed as causative factors. Recently, we found that hepatic phosphoglycoprotein 3 (pgp3) activity was reduced in pigs during bilirubin-induced uncoupling of biliary lipid from bile acid secretion. Pgp3 is the phosphatidylcholine flippase in the canalicular membrane sustaining biliary phospholipid secretion in pigs. This investigation was undertaken to examine whether bilirubin, dibromosulfophthalein, and bromosulfophthalein uncouple biliary lipid from bile acid secretion by the same mechanism. METHODS/RESULTS: Hepatic bile was collected from 24 anesthetized pigs before and during infusion of 0.63 micromol x kg body wt(-1) x min(-1) intravenous bilirubin, dibromosulfophthalein, or bromosulfophthalein. Bile acid secretion was varied by intraportal cholic acid infusion. Hepatic pgp3 expression was measured by means of Western blot, using C219 antibody. Bilirubin > dibromosulfophthalein > bromosulfophthalein lowered biliary lipid secretion without altering hepatic pgp3 expression, increased bile acid-independent bile flow (bromosulfophthalein > dibromosulfophthalein > bilirubin), and enhanced the capacity of bile to micellize membrane lipids as assayed by means of erythrocyte lysis. Biliary bile acid concentration did not determine biliary lipid secretion. CONCLUSION: Bilirubin, dibromosulfophthalein, and bromosulfophthalein in bile uncouple biliary lipid from bile acid secretion by inhibiting hepatic pgp3 phosphatidylcholine flippase activity, putatively through diffusing into the pgp3 pore.

Effect of intravenous bilirubin infusion on biliary phospholipid secretion, hepatic P-glycoprotein expression, and biliary cytotoxicity in pigs.

BACKGROUND: Infusion of large intravenous bilirubin loads in bile acid-depleted pigs reduces P-glycoprotein-dependent biliary phospholipid secretion and increases the cytotoxicity of bile. The reasons for the diminution of biliary phospholipid secretion and the increase in biliary cytotoxicity are not known. This study was undertaken to determine whether the bilirubin-induced lowering of biliary phospholipid secretion is associated with alterations in hepatic P-glycoprotein (P-gp) expression and to determine why bilirubin infusions increase biliary cytotoxicity. METHODS: Hepatic bile was collected from bile acid-depleted pigs before and during intravenous bilirubin infusion. Hepatic P-gp expression was measured with protein blot analysis, using the P-gp-specific antibody C219. Biliary cytotoxicity was assayed against erythrocytes. The biliary phospholipid fatty acid profile was determined by means of gas chromatography. RESULTS: Bilirubin infusions lowered biliary phospholipid secretion by 69% without changing hepatic P-gp expression, suggesting that bilirubin infusions have an inhibitory effect on hepatic P-gp activity. Bilirubin infusions did not cause P-gp losses into bile. An unequivocal, proportional relationship (r2 = 0.80) pertained between cytotoxicity and the bile acid to phospholipid ratio in bile secreted before and during bilirubin infusion and in phosphatidylcholine-supplemented bile. Unconjugated bilirubin in bile did not contribute to biliary cytotoxicity. Biliary phospholipids were always phosphatidylcholine >> phosphatidylethanolamine, mainly of C16:0, 18:2 and C16:0, 18:1 fatty acid configuration. CONCLUSIONS: Intravenous bilirubin loads reduce biliary phospholipid secretion without changing hepatic P-gp expression. Bilirubin infusions increase biliary cytotoxicity by augmenting the biliary bile acid to phospholipid ratio.