Crystalline silica alters Sulfatase-1 expression in rat lungs which influences hyper-proliferative and fibrogenic effects in human lung epithelial cells.

Lung epithelial cells are the first cell-type to come in contact with hazardous dust materials. Upon deposition, they invoke complex reactions in attempt to eradicate particles from the airways, and repair damage. The cell surface is composed of a heterogeneous network of matrix proteins and proteoglycans, which act as scaffold and control cell-signaling networks. These functions are controlled, in part, by the sulfation patterns of heparin-sulfate proteoglycans (HSPGs), which are enzymatically regulated. Although there is evidence of altered HSPG-sulfation in idiopathic pulmonary fibrosis (IPF), this is not investigated in silicosis. Our previous studies revealed down-regulation of Sulfatase-1 (SULF1) in human bronchial epithelial cells (BECs) by crystalline silica (CS). In this study, CS-induced down-regulation of SULF1, and increases in Sulfated-HSPGs, were determined in human BECs, and in rat lungs. By siRNA and plasmid transfection techniques the effects of SULF1 expression on silica-induced fibrogenic and proliferative gene expression were determined. These studies confirmed down-regulation of SULF1 and subsequent increases in sulfated-HSPGs in vitro. Moreover, short-term exposure of rats to CS resulted in similar changes in vivo. Conversely, effects were reversed after long term CS exposure of rats. SULF1 knockdown, and overexpression alleviated and exacerbated silica-induced decrease in cell viability, respectively. Furthermore, overexpression of SULF1 promoted silica-induced proliferative and fibrogenic gene expression, and collagen production. These findings demonstrate that the HSPG modification enzyme SULF1 and HSPG sulfation are altered by CS in vitro and in vivo. Furthermore, these changes may contribute to CS-induced lung pathogenicity by affecting injury tolerance, hyperproliferation, and fibrotic effects.

Unique clinical conditions associated with different acinar regions of fibrosis in long-term surviving pediatric liver grafts.

In the majority of long-term survivors after PLTx, graft fibrosis has been identified. Recently, subtypes of graft fibrosis have been described based on their predominant acinar localization. We aimed to evaluate whether the development of portal, perisinusoidal, and centrilobular distribution of graft fibrosis is related to patient or transplantation-related parameters. We reviewed the histological features in protocol liver biopsies taken at 1 and 5 years after PLTx of 47 children on a tacrolimus-based immunosuppressive regimen. Fibrosis was assessed according to the LAFSc. The prevalence of portal fibrosis increased from 31% to 62%, sinusoidal from 68% to 79%, and centrilobular from 76% to 85%. The presence of portal fibrosis was associated with total bilirubin and γGT levels (each P<.02) and tended to be associated with biliary complications (P=.06). Sinusoidal fibrosis was associated with prior rejection episodes (P<.02) and centrilobular fibrosis with the presence of HLA mismatches (P=.02). In conclusion, using the LAFSc, we found a high incidence of progressive fibrosis in the 1-year and 5-year protocol biopsies after PLTx. Progression of fibrosis was observed in all acinar compartments, and each of the three locations is associated with different clinical conditions.

The timing of surgery of antenatally diagnosed choledochal malformations: A descriptive analysis of a 26-year nationwide cohort.

INTRODUCTION: Choledochal malformations (CMs) are increasingly diagnosed antenatally. There is a dilemma between early surgery to prevent CM-related symptoms and postponing surgery to reduce complications. We aimed to identify the optimal timing of surgery in asymptomatic neonates with antenatally diagnosed CM and to identify predictors for development of symptoms. METHODS: Using the Netherlands Study group on CHoledochal Cyst/malformation (NeSCHoc) we retrospectively collected demographic, biochemical and surgical data from all Dutch patients with an antenatally detected CM. RESULTS: Between 1989 and 2014, antenatally suspected CM was confirmed in 17 patients at a median age of 10days (1day-2months). Four patients developed symptoms directly after birth (24%). Thirteen patients (76%) remained asymptomatic. Two of these progressed to symptoms before surgical intervention at 0.7 and 2.1months resp. Postoperatively, four patients developed short-term complications and three developed long-term complications. Patients <5.6kg (the series median) showed more short-term complications (66%) when compared to patients >5.6kg (0%, p=0.02). CONCLUSION: When not symptomatic within the first days of life, the majority of children with antenatally detected CM remains asymptomatic. Surgery might safely be delayed to the age of 6months or a weight of 6kg. Postponing surgery in the clinically and biochemical asymptomatic patient might decrease the complication rate. LEVELS OF EVIDENCE: Level III.

Intraoperative frozen section analysis of the proximal bile ducts in hilar cholangiocarcinoma is of limited value.

Frozen section analysis (FS) during cancer surgery is widely used to assess resection margins. However, in hilar cholangiocarcinoma (HCCA), FS may be less reliable because of the specific growth characteristics of the tumor. The aim of this study was to determine the accuracy and consequences of intraoperative FS of the proximal bile duct margins in HCCA. Between 1990 and 2014, 67 patients underwent combined extrahepatic bile duct resection and partial liver resection for HCCA with the use of FS. Sensitivity and specificity of FS was 68% and 97%, respectively. Seventeen of 67 patients (25%) displayed a positive bile duct margin at FS. The false-negative rate was 16% (eight patients). Ten patients (15%) with a positive bile duct margin underwent an additional resection in an attempt to achieve negative margins, which succeeded in three patients (4%). However, only one of these three patients did not have concomitant lymph node metastases, which are associated with a poor prognosis by itself. The use of FS of the proximal bile duct is of limited clinical value because of the relatively low sensitivity, high risk of false-negative results, and the low rate of secondary obtained tumor-free resection margins. Supported by the literature, a new approach to the use of FS in HCCA should be adopted, reserving the technique only for cases in which a substantial additional resection is possible.

Immune Homeostasis in Epithelial Cells: Evidence and Role of Inflammasome Signaling Reviewed.

The epithelium regulates the interaction between the noxious xenogenous, as well as the microbial environment and the immune system, not only by providing a barrier but also by expressing a number of immunoregulatory membrane receptors, and intracellular danger sensors and their downstream effectors. Amongst these are a number of inflammasome sensor subtypes, which have been initially characterized in myeloid cells and described to be activated upon assembly into multiprotein complexes by microbial and environmental triggers. This review compiles a vast amount of literature that supports a pivotal role for inflammasomes in the various epithelial barriers of the human body as essential factors maintaining immune signaling and homeostasis.

Strong Upregulation of AIM2 and IFI16 Inflammasomes in the Mucosa of Patients with Active Inflammatory Bowel Disease.

BACKGROUND: Inflammatory bowel disease (IBD) is characterized by a chronic inflammation of the gut, partly driven by defects in the innate immune system. Considering the central role of inflammasome signaling in innate immunity, we studied inflammasome components in IBD mucosa. METHODS: Expression of genes encoding inflammasome sensor subunits was investigated in colonic mucosal biopsies from 2 cohorts of patients with IBD and controls. RESULTS: A significant upregulation (>2-fold change in expression, false discovery rate <0.05) of the PYHIN inflammasomes AIM2 and IFI16 in active IBD versus controls was found. Also IFI16 was significantly increased in inactive IBD versus controls. Moreover, responders to anti-tumor necrosis factor therapy showed decreased expression of these inflammasomes although IFI16 remained significantly increased in responders showing endoscopic healing versus controls. AIM2 was mainly expressed in epithelial cells, whereas IFI16 was expressed in both lymphocytes and epithelial cells. Functional activation of predominant AIM2/IFI16-mediated inflammasomes in active IBD colon was shown by the presence of the downstream effectors CASP1 and HMGB-1 in inflamed mucosa. CONCLUSIONS: Our results highlight the importance of PYHIN inflammasome signaling in IBD and also link anti-tumor necrosis factor responsiveness to inflammasome signaling. Together, this points to the potential value of the inflammasome pathway as a new therapeutic target for IBD treatment.

Achievement of developmental milestones in young adults after liver transplantation in childhood.

Little is known about the achievement of developmental milestones (i.e., COL) after pediatric liver transplantation. The aim of this study was to examine the COL of young adults who underwent a liver transplantation during childhood and to compare it to healthy peers. Furthermore, we studied factors possibly related to their COL. COL was assessed using the CLQ, which assesses the achievement of developmental milestones (autonomy, psychosexual, social, and antisocial development) and risk behavior (substance abuse and gambling). Sociodemographic characteristics and clinical data were collected using the prospective institutional liver transplantation database. A total of 39 young adults who underwent a liver transplantation at the UMCG in their childhood completed the CLQ. They achieved fewer milestones with regard to autonomy, psychosexual, and social development compared to healthy peers, and they reported less risk behavior. Neither age at the time of study nor age at the time of transplantation was significantly correlated with any of the COL subscales. Young adults show delay in reaching developmental milestones in every dimension after a liver transplantation during their childhood.

Liver Transplantation in Groningen, The Netherlands: A Single Center Status Report.

The liver transplantation program of the University Medical Center Groningen in the Netherlands was started in 1979, making it one of the first programs worldwide. During the past 36 years, a total of 1478 liver transplantations have been performed, 459 of which were in children. One of the first patients transplanted in 1979 is still alive and is one of the longest surviving patients after liver transplantation worldwide. During the last decade, an increasing number of donation after circulatory death (DCD) donor livers have been accepted for transplantation. Over 30% of the livers transplanted in Groningen come from DCD donors. These livers have an increased risk of developing biliary complications, such as non-anastomotic biliary strictures (NAS). One of the main research topics in Groningen has been the pathogenesis and prevention of NAS. In an attempt to reduce the incidence of NAS after liver transplantation, machine perfusion technology has been developed as an alternative to the traditional method of static cold storage. Researchers of the Groningen liver transplant team were the first in the world to report a method of ex situ normothermic machine perfusion of human donor livers. The efficacy and safety of various types of machine perfusion are currently studied in both animal models and clinical trials. A second line of research in Groningen focuses on alterations in the blood coagulation system in patients with liver disease and undergoing liver transplantation. Groningen researchers were the first to describe a 'rebalanced state' of the coagulation system in patients with liver disease, making them prone to both bleeding and thrombo-embolic complications. Clinicians and researchers at the Groningen liver transplant program will continue to collaborate with a shared focus and the aim to provide innovation and the highest level of care to patients with endstage liver disease.

Health status and quality of life in adult biliary atresia patients surviving with their native livers.

INTRODUCTION: Gaining an insight into the quality of life (QOL) in long-term biliary atresia (BA) survivors is becoming more important. Identifying patients with limitations might make tailor made interventions possible. This is the first study investigating the health status (HS) and QOL in adults surviving BA with their native livers, and comparing them with healthy peers. METHODS: BA patients surviving with their native liver were identified in the Netherlands Study Group on Biliary Atresia Registry database. The RAND-36 and the World Health Organization Quality of Life assessment instrument-100 (WHOQOL-100) were used to measure HS and QOL, respectively. Correlation between the RAND-36 and WHOQOL-100 was also assessed. Hospital Anxiety and Depression Scale (HADS) and the Impact Event Scale (IES) were also completed. RESULTS: In total, 25 (83%) of the 30 eligible patients after Kasai portoenterostomy completed the questionnaires (median age 23.2 years). A lower perceived level of general health in HS was found as compared with the reference group and a higher score on the social domain was reported in QOL. Correlations between HS and QOL questionnaires were moderate to good. For the group, overall HADS and IES scores were good, though individual patients did score above the cutoff of both the questionnaires. CONCLUSION: Adult BA patients surviving with their native liver have similar HS and QOL as compared with their healthy peers. RAND-36 and WHOQOL-100 questionnaires are not interchangeable, but complementary to assess the patients' outcomes. The overall scores did not point to increased levels of anxiety and depression. However, on an individual level, three and six patients had a score above the cutoff of the HADS subscales demonstrating clinically relevant levels of anxiety and depression, respectively.

Controversies in Choledochal Malformations: A Survey among Dutch Pediatric Surgeons.

BACKGROUND: Choledochal malformation (CM) is a rare medical condition of which 80% are diagnosed in pediatric patients. There are several important controversies regarding diagnostic workup, management, and follow-up in these pediatric patients. To assess preferences and practices of Dutch pediatric surgeons regarding the diagnostic procedures, management, and follow-up of children with CM we conducted an electronic survey. METHODS: A questionnaire was sent to all the pediatric surgeons working in the academic centers and the only community hospital with a pediatric surgery service. The questionnaire included, items regarding incidence, diagnostic workup, interval between diagnosis and surgery, surgical techniques, and follow-up. We also assessed whether personal exposure influenced the preferences and practices. RESULTS: Overall 22 out of the 31 (71%) Dutch pediatric surgeons returned the questionnaire. Total 15 out of 22 (68%) encountered CM up to 2 times/y, whereas 7 out of 22 (32%) encountered it more than 2 times/y. Indications for surgery were significantly different between surgeons who encountered CM > 2 time/y versus those who did not: 6/6 (100%) of surgeons encountering CM > 2 times/y considered the presence of an asymptomatic CM an indication for surgery versus 5/14 (36%) of the pediatric surgeons who encountered a CM up to 2 times/y (p = 0.01). Overall 12 out of the 22 (55%) respondents preferred surgery between 6 months and 2 years of age. The amount of exposure did not differ in preferred age at surgery or surgical technique. In the symptomatic child 10/22 (45%) of respondents preferred surgery within 3 months. Overall 7/22 (32%) favored laparoscopic resection. Hepaticojejunostomy with Roux-en-Y reconstruction was the preferred reconstruction for all the respondents. One-third stated that they never performed a parenchyma resection. Follow-up was limited to 10 years in almost half of the respondents. CONCLUSION: Dutch pediatric surgeons demonstrate a wide variety of opinions regarding diagnostic workup, treatment, and follow-up of CM. While most surgeons encounter CM up to 2 times/y, there is an association between exposure and several of the outcome parameters. Some of the answers are not in line with the expert opinion. This demonstrates that there is a need for evidence-based (inter)national guidelines regarding the diagnostic approach, management, and follow-up.

Indications for distinct pathogenic mechanisms of asbestos and silica through gene expression profiling of the response of lung epithelial cells.

Occupational and environmental exposures to airborne asbestos and silica are associated with the development of lung fibrosis in the forms of asbestosis and silicosis, respectively. However, both diseases display distinct pathologic presentations, likely associated with differences in gene expression induced by different mineral structures, composition and bio-persistent properties. We hypothesized that effects of mineral exposure in the airway epithelium may dictate deviating molecular events that may explain the different pathologies of asbestosis versus silicosis. Using robust gene expression-profiling in conjunction with in-depth pathway analysis, we assessed early (24 h) alterations in gene expression associated with crocidolite asbestos or cristobalite silica exposures in primary human bronchial epithelial cells (NHBEs). Observations were confirmed in an immortalized line (BEAS-2B) by QRT-PCR and protein assays. Utilization of overall gene expression, unsupervised hierarchical cluster analysis and integrated pathway analysis revealed gene alterations that were common to both minerals or unique to either mineral. Our findings reveal that both minerals had potent effects on genes governing cell adhesion/migration, inflammation, and cellular stress, key features of fibrosis. Asbestos exposure was most specifically associated with aberrant cell proliferation and carcinogenesis, whereas silica exposure was highly associated with additional inflammatory responses, as well as pattern recognition, and fibrogenesis. These findings illustrate the use of gene-profiling as a means to determine early molecular events that may dictate pathological processes induced by exogenous cellular insults. In addition, it is a useful approach for predicting the pathogenicity of potentially harmful materials.

Silica-induced NLRP3 inflammasome activation in vitro and in rat lungs.

RATIONALE: Mineral particles in the lung cause inflammation and silicosis. In myeloid and bronchial epithelial cells the inflammasome plays a role in responses to crystalline silica. Thioredoxin (TRX) and its inhibitory protein TRX-interacting protein link oxidative stress with inflammasome activation. We investigated inflammasome activation by crystalline silica polymorphs and modulation by TRX in vitro, as well as its localization and the importance of silica surface reactivity in rats. METHODS: We exposed bronchial epithelial cells and differentiated macrophages to silica polymorphs quartz and cristobalite and measured caspase-1 activity as well as the release of IL-1ß, bFGF and HMGB1; including after TRX overexpression or treatment with recombinant TRX. Rats were intratracheally instilled with vehicle control, Dörentruper quartz (DQ12) or DQ12 coated with polyvinylpyridine N-oxide. At days 3, 7, 28, 90, 180 and 360 five animals per treatment group were sacrificed. Hallmarks of silicosis were assessed with Haematoxylin-eosin and Sirius Red stainings. Caspase-1 activity in the bronchoalveolar lavage and caspase-1 and IL-1ß localization in lung tissue were determined using Western blot and immunohistochemistry (IHC). RESULTS: Silica polymorphs triggered secretion of IL-1ß, bFGF and HMGB1 in a surface reactivity dependent manner. Inflammasome readouts linked with caspase-1 enzymatic activity were attenuated by TRX overexpression or treatment. At day 3 and 7 increased caspase-1 activity was detected in BALF of the DQ12 group and increased levels of caspase-1 and IL-1ß were observed with IHC in the DQ12 group compared to controls. DQ12 exposure revealed silicotic nodules at 180 and 360 days. Particle surface modification markedly attenuated the grade of inflammation and lymphocyte influx and attenuated the level of inflammasome activation, indicating that the development of silicosis and inflammasome activation is determined by crystalline silica surface reactivity. CONCLUSION: Our novel data indicate the pivotal role of surface reactivity of crystalline silica to activate the inflammasome in cultures of both epithelial cells and macrophages. Inhibitory capacity of the antioxidant TRX to inflammasome activation was evidenced. DQ12 quartz exposure induced acute and chronic functional activation of the inflammasome in the heterogeneous cell populations of the lung in associated with its crystalline surface reactivity.

Silica induces NLRP3 inflammasome activation in human lung epithelial cells.

BACKGROUND: In myeloid cells the inflammasome plays a crucial role in innate immune defenses against pathogen- and danger-associated patterns such as crystalline silica. Respirable mineral particles impinge upon the lung epithelium causing irreversible damage, sustained inflammation and silicosis. In this study we investigated lung epithelial cells as a target for silica-induced inflammasome activation. METHODS: A human bronchial epithelial cell line (BEAS-2B) and primary normal human bronchial epithelial cells (NHBE) were exposed to toxic but nonlethal doses of crystalline silica over time to perform functional characterization of NLRP3, caspase-1, IL-1ß, bFGF and HMGB1. Quantitative RT-PCR, caspase-1 enzyme activity assay, Western blot techniques, cytokine-specific ELISA and fibroblast (MRC-5 cells) proliferation assays were performed. RESULTS: We were able to show transcriptional and translational upregulation of the components of the NLRP3 intracellular platform, as well as activation of caspase-1. NLRP3 activation led to maturation of pro-IL-1ß to secreted IL-1ß, and a significant increase in the unconventional release of the alarmins bFGF and HMGB1. Moreover, release of bFGF and HMGB1 was shown to be dependent on particle uptake. Small interfering RNA experiments using siNLRP3 revealed the pivotal role of the inflammasome in diminished release of pro-inflammatory cytokines, danger molecules and growth factors, and fibroblast proliferation. CONCLUSION: Our novel data indicate the presence and functional activation of the NLRP3 inflammasome by crystalline silica in human lung epithelial cells, which prolongs an inflammatory signal and affects fibroblast proliferation, mediating a cadre of lung diseases.

Differences in gene expression and cytokine production by crystalline vs. amorphous silica in human lung epithelial cells.

BACKGROUND: Exposure to respirable crystalline silica particles, as opposed to amorphous silica, is associated with lung inflammation, pulmonary fibrosis (silicosis), and potentially with lung cancer. We used Affymetrix/GeneSifter microarray analysis to determine whether gene expression profiles differed in a human bronchial epithelial cell line (BEAS 2B) exposed to cristobalite vs. amorphous silica particles at non-toxic and equal surface areas (75 and 150 × 106µm2/cm2). Bio-Plex analysis was also used to determine profiles of secreted cytokines and chemokines in response to both particles. Finally, primary human bronchial epithelial cells (NHBE) were used to comparatively assess silica particle-induced alterations in gene expression. RESULTS: Microarray analysis at 24 hours in BEAS 2B revealed 333 and 631 significant alterations in gene expression induced by cristobalite at low (75) and high (150 × 106µm2/cm2) amounts, respectively (p < 0.05/cut off ≥ 2.0-fold change). Exposure to amorphous silica micro-particles at high amounts (150 × 106µm2/cm2) induced 108 significant gene changes. Bio-Plex analysis of 27 human cytokines and chemokines revealed 9 secreted mediators (p < 0.05) induced by crystalline silica, but none were induced by amorphous silica. QRT-PCR revealed that cristobalite selectively up-regulated stress-related genes and cytokines (FOS, ATF3, IL6 and IL8) early and over time (2, 4, 8, and 24 h). Patterns of gene expression in NHBE cells were similar overall to BEAS 2B cells. At 75 × 106µm2/cm2, there were 339 significant alterations in gene expression induced by cristobalite and 42 by amorphous silica. Comparison of genes in response to cristobalite (75 × 106µm2/cm2) revealed 60 common, significant gene alterations in NHBE and BEAS 2B cells. CONCLUSIONS: Cristobalite silica, as compared to synthetic amorphous silica particles at equal surface area concentrations, had comparable effects on the viability of human bronchial epithelial cells. However, effects on gene expression, as well as secretion of cytokines and chemokines, drastically differed, as the crystalline silica induced more intense responses. Our studies indicate that toxicological testing of particulates by surveying viability and/or metabolic activity is insufficient to predict their pathogenicity. Moreover, they show that acute responses of the lung epithelium, including up-regulation of genes linked to inflammation, oxidative stress, and proliferation, as well as secretion of inflammatory and proliferative mediators, can be indicative of pathologic potential using either immortalized lines (BEAS 2B) or primary cells (NHBE). Assessment of the degree and magnitude of these responses in vitro are suggested as predictive in determining the pathogenicity of potentially harmful particulates.

Biliary atresia in the Netherlands: outcome of patients diagnosed between 1987 and 2008.

OBJECTIVE: To examine the outcome of biliary atresia (BA) and to identify prognostic factors using a national database. STUDY DESIGN: All children born between January 1987 and December 2008 who underwent the Kasai surgical procedure for BA were retrieved from the Netherlands Study Group on Biliary Atresia Registry database. Outcomes were measured in terms of clearance of jaundice (bilirubin <1.17 g/dL, or 20 µmol/L, within 6 months after surgery) and 4-year transplant-free survival. Two cohorts, one from 1987-1997 and the other from 1998-2008, were compared. Survival rates were determined using Kaplan-Meier analysis, and prognostic factors were tested with univariate and multivariate analyses. RESULTS: Between January 1987 and December 2008, 214 patients underwent Kasai surgery for BA. In this series, the 4-year transplant-free survival was 46%±4%, and 4-year overall survival was 73%±3%. Clearance of jaundice, surgery within 60 days, and postoperative antibiotic prophylaxis use were independently associated with increased transplant-free survival. The yearly caseload per center (range, 0.5-2.1) was not correlated with transplant-free survival (r=0.024; P=.73). CONCLUSION: During the past 2 decades, outcome parameters have remained constant and are comparable with those reported from other Western countries, despite a relatively low annual caseload per center. Timely surgical correction and postoperative antibiotic therapy were associated with a higher transplant-free survival rate.

Mortality of biliary atresia in children not undergoing liver transplantation in the Netherlands.

In order to further improve the outcome of BA, we characterized the mortality of BA patients who did not undergo OLT in the Netherlands, and compared our results with international data. For this purpose, we analyzed the causes of mortality of non-transplanted BA patients before the age of five yr, using the NeSBAR database. To evaluate trends in mortality, we compared the cohort 1987-1996 (n=99) with 1997-2008 (n=111). We compared clinical condition at OLT assessment with available international data, using the PELD-score. Mortality of non-transplanted BA children was 26% (26/99) in 1987-1996 and 16% (18/111) in 1997-2008 (p=0.09). Sepsis was the prevailing direct cause of death (30%; 13/44). PELD-scores at the time of assessment were higher in non-transplanted BA patients (median 20.5; range 13-40) compared with international data (mean/median between 11.7 and 13.3). Based on our national data, we conclude that pretransplant mortality of BA patients is still considerable, and that sepsis is a predominant contributor. Our results strongly indicate that the prognosis of patients with BA in the Netherlands can be improved by earlier listing of patients for OLT and by improving pretransplant care.

Long-term results of urgent revascularization for hepatic artery thrombosis after pediatric liver transplantation.

Hepatic artery thrombosis (HAT) after pediatric orthotopic liver transplantation (OLT) is a serious complication resulting in bile duct necrosis and often requiring retransplantation. Immediate surgical thrombectomy/thrombolysis has been reported to be a potentially successful treatment for restoring blood flow and avoiding urgent retransplantation. The long-term results of this strategy remain to be determined. In 232 pediatric liver transplants, we analyzed long-term outcomes after urgent revascularization for early HAT. HAT developed in 32 patients (13.7%). In 16 children (50%), immediate surgical thrombectomy was performed in an attempt to salvage the graft. Fourteen patients (44%) underwent urgent retransplantation, and 2 (6%) died before further intervention. Immediate thrombectomy resulted in long-term restoration of the hepatic artery flow in 6 of 16 patients (38%) and in 1- and 5-year graft and patient survival rates of 83% and 67%, respectively. In 10 patients, revascularization was unsuccessful, and retransplantation was inevitable. The 1- and 5-year patient survival rates in this group decreased to 50% and 40%, respectively. After immediate retransplantation, the 5-year patient survival rate was 71%. In conclusion, immediate surgical thrombectomy for HAT after pediatric OLT results in long-term graft salvage in about one-third of patients. However, when thrombectomy is unsuccessful, long-term patient survival is lower than the survival of patients who underwent immediate retransplantation.

Immediate postoperative low platelet count is associated with delayed liver function recovery after partial liver resection.

OBJECTIVE: To evaluate whether a low postoperative platelet count is associated with a poor recovery of liver function in patients after partial liver resection. BACKGROUND: Experimental studies in rodents have recently suggested that blood platelets play a critical role in the initiation of liver regeneration. It remains unclear whether platelets are also involved in liver regeneration in humans. METHODS: In a series of 216 consecutive patients who underwent partial liver resection for colorectal liver metastases, we studied postoperative mortality and liver dysfunction in relation to the immediate postoperative platelet count. All patients had normal preoperative liver function and none of them had liver fibrosis or cirrhosis. Delayed postoperative recovery of liver function was defined as serum bilirubin >50 micromol/L or prothrombin time >20 seconds at any time point between postoperative day 1 and 5. RESULTS: Patients with a low (<100 x10(9)/L) immediate postoperative platelet count had worse postoperative liver function, higher serum markers of liver injury, and increased mortality compared with patients with normal platelet counts (>100/L). A low immediate postoperative platelet count was identified as an independent risk factor of delayed postoperative recovery of liver function (OR, 11.5; 95% CI, 1.1-122.4; P = 0.04 in multivariate analysis). CONCLUSION: After partial liver resection, a low platelet count is an independent predictor of delayed postoperative liver function recovery and is associated with increased risk of postoperative mortality. These clinical findings are in accordance with the accumulating evidence from experimental studies, indicating that platelets play a critical role in liver regeneration.

The clinical relevance of the anhepatic phase during liver transplantation.

This study assesses the relation between the anhepatic phase duration and the outcome after liver transplantation. Of 645 patients who underwent transplantation between 1994 and 2006, 194 were recipients of consecutive adult primary piggyback liver transplants using heart-beating donors. The anhepatic phase was defined as the time from the physical removal of the liver from the recipient to recirculation of the graft. Other noted study variables were the cold and warm ischemia times, donor and recipient age, donor and recipient body mass index, perioperative red blood cell (RBC) transfusion, indication for transplantation, and Model for End-Stage Liver Disease score. The primary outcome parameter was graft dysfunction, which was defined as either primary nonfunction or initial poor function according to the Ploeg-Maring criteria. The median anhepatic phase was 71 minutes (37-321 minutes). Graft dysfunction occurred in 27 patients (14%). Logistic regression analysis showed an anhepatic phase over 100 minutes [odds ratio (OR), 4.28], a recipient body mass index over 25 kg/m(2) (OR, 3.21), and perioperative RBC transfusion (OR, 3.04) to be independently significant predictive factors for graft dysfunction. One-year patient survival in patients with graft dysfunction was 67% versus 92% in patients without graft dysfunction (P < 0.001). A direct relation between the anhepatic phase duration and patient survival could, however, not be established. In conclusion, this study shows that liver transplant patients with an anhepatic phase over 100 minutes have a higher incidence of graft dysfunction. Patients with graft dysfunction have significantly worse 1-year patient survival.