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Venkataswarup Tiriveedhi, Kendra D Conzen,
Jane Liaw-Conlin,
Gundumi Upadhya,
James Malone,
R Reid Townsend,
Robnet Kerns,
Jianluo Jia,
Krista Csontos,
Sabarinathan Ramachandran,
Thallachallour Mohanakumar,
Christopher D Anderson,
William C Chapman
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ABSTRACT: The molecular basis of the increased susceptibility of steatotic livers to warm ischemia/reperfusion (I/R) injury during transplantation remains undefined. Animal model for warm I/R injury was induced in obese Zucker rats. Lean Zucker rats provided controls. Two dimensional differential gel electrophoresis was performed with liver protein extracts. Protein features with significant abundance ratios (p < 0.01) between the two cohorts were selected and analyzed with HPLC/MS. Proteins were identified by Uniprot database. Interactive protein networks were generated using Ingenuity Pathway Analysis and GRANITE software.
The relative abundance of 105 proteins was observed in warm I/R injury. Functional grouping revealed four categories of importance: molecular chaperones/endoplasmic reticulum (ER) stress, oxidative stress, metabolism, and cell structure. Hypoxia up-regulated 1, calcium binding protein 1, calreticulin, heat shock protein (HSP) 60, HSP-90, and protein disulfide isomerase 3 were chaperonins significantly (p < 0.01) down-regulated and only one chaperonin, HSP-1was significantly upregulated in steatotic liver following I/R.
Down-regulation of the chaperones identified in this analysis may contribute to the increased ER stress and, consequently, apoptosis and necrosis. This study provides an initial platform for future investigation of the role of chaperones and therapeutic targets for increasing the viability of steatotic liver allografts.
BMC Biochemistry 09/2012; 13:17. · 1.99 Impact Factor
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ABSTRACT: Although inflow occlusion techniques have given surgeons the ability to carry out increasingly complex liver resections, ischemia-reperfusion (IR) injury continues to be a source of morbidity. Efforts to ameliorate IR injury have been hindered in absence of adequate preclinical models. The goal of the present study was to develop a simple, efficient, and cost-effective means of studying hepatic IR injury.
Liver cubes were procured from normal (C57BL/6) mice. After hepatectomy, 4-mm punch biopsies were taken for individual placement in culture wells containing hepatocyte media. Experimental cubes underwent hypoxia for 60 minutes, whereas controls remained normoxic. Supernatants were collected from individual wells after 0, 6, and 12 hours of rediffusion for transaminase and cytokine measurement. Histologic examination was performed on individual cubes.
Extensive histologic injury was seen in the experimental cubes compared with controls with greater staining for activated caspase-3 and terminal deoxynucleotidyl transferase dUTP nick end labeling at 6 and 24 hours, respectively. Changes consistent with ischemic injury occurred more centrally in liver cubes, whereas markers for rediffusion injury were appreciated along the periphery. Transaminases were significantly higher at 6 hours after rediffusion in experimental cubes compared with controls (P = .02). tumor necrosis factor-α and interleukin-1β were significantly higher in the media of experimental cubes compared with controls at 12 hours rediffusion (P = .05 and .03 respectively).
In vitro IR of cubes produces a significant injury with a pattern reflective of hepatic lobular architecture. This novel technique may open new avenues for uncoupling the mechanisms of IR while facilitating rapid screening of potential therapies.
Surgery 06/2012; 152(2):247-53. · 3.10 Impact Factor
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ABSTRACT: A strategy to increase the number of size- and weight-appropriate organs and decrease the paediatric waiting list mortality is wider application of sectional orthotopic liver transplantation (OLT). These technical variants consist of living donor, deceased donor reduced and split allografts. However, these grafts have an increased risk of biliary complications. An unusual and complex biliary complication which can lead to graft loss is inadvertent exclusion of a major segmental bile duct. We present four cases and describe an algorithm to correct these complications.
A retrospective review of the paediatric orthotopic liver transplantation database (2000-2010) at Washington University in St. Louis/St. Louis Children's Hospital was conducted.
Sixty-eight patients (55%) received technical variant allografts. Four complications of excluded segmental bile ducts were identified. Percutaneous cholangiography provided diagnostic confirmation and stabilization with external biliary drainage. All patients required interval surgical revision of their hepaticojejunostomy for definitive drainage. Indwelling biliary stents aided intra-operative localization of the excluded ducts. All allografts were salvaged.
Aggressive diagnosis, percutaneous decompression and interval revision hepaticojejunostomy are the main tenets of management of an excluded bile duct. Careful revision hepaticojejunostomy over a percutaneous biliary stent can result in restoration of biliary continuity and allograft survival.
HPB 12/2011; 13(12):893-8. · 1.60 Impact Factor
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ABSTRACT: With pre-operative prediction of liver volume becoming increasingly important to safely carry out complex hepatic resections, the aim of the present study was to validate the accuracy of a three-dimensional (3-D) liver surgery operative planning software in performing hepatic volumetry.
Between 1999 and 2007, we performed 29 live donor liver resections for transplantation. Eleven patients had pre-operative volumetry performed by radiologists from either computed tomography (CT) or magnetic resonance (MR) imaging with documentation of the corresponding specimen weight. Retrospectively, images were uploaded into Scout™ where 3-D models of each case were generated to perform volumetry. A correlational analysis was performed followed by an accuracy comparison.
Estimations by both radiologists and Scout™ were significantly correlated with the specimen weights, P ≤ 0.0001. Compared with radiologists' volumetry, Scout™ significantly improved overall accuracy [per cent error (PE) 20.0% ± 5.3 vs. 32.9% ± 5.7, P=0.005], accuracy of CT-based estimations (PE 23.2% ± 6.7 vs. 37.2% ± 6.9, P=0.023) and accuracy of the left lateral section (PE 11.1% ± 3.9 vs. 26.6% ± 6.8, P=0.027).
This 3-D planning software is a valid tool for use in volumetry. Significance is greatest for CT-based models of the left lateral section. This approach gives surgeons the ability to assess volumetrics and actively plan resections.
HPB 09/2011; 13(9):670-4. · 1.60 Impact Factor
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Christopher D Anderson,
Gundumi Upadhya, Kendra D Conzen,
Jianlou Jia,
Elizabeth M Brunt,
Venkataswarup Tiriveedhi,
Yan Xie,
Sabarinathan Ramachandran,
Thalachallour Mohanakumar,
Nicholas O Davidson,
William C Chapman
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ABSTRACT: Hepatic steatosis continues to present a major challenge in liver transplantation. These organs have been shown to have increased susceptibility to cold ischemia/reperfusion (CIR) injury in comparison with otherwise comparable lean livers; the mechanisms governing this increased susceptibility to CIR injury are not fully understood. Endoplasmic reticulum (ER) stress is an important link between hepatic steatosis, insulin resistance, and metabolic syndrome. In this study, we investigated ER stress signaling and blockade in the mediation of CIR injury in severely steatotic rodent allografts. Steatotic allografts from genetically leptin-resistant rodents had increased ER stress responses and increased markers of hepatocellular injury after liver transplantation into strain-matched lean recipients. ER stress response components were reduced by the chemical chaperone taurine-conjugated ursodeoxycholic acid (TUDCA), and this resulted in an improvement in the allograft injury. TUDCA treatment decreased nuclear factor kappa B activation and the proinflammatory cytokines interleukin-6 and interleukin-1β. However, the predominant response was decreased expression of the ER stress cell death mediator [CCAAT/enhancer-binding protein homologous protein (CHOP)]. Furthermore, activation of inflammation-associated caspase-11 was decreased, and this linked ER stress/CHOP to proinflammatory cytokine production after steatotic liver transplantation. These data confirm ER stress in steatotic allografts and implicate this as a mediating mechanism of inflammation and hepatocyte death in the steatotic liver allograft.
Liver Transplantation 02/2011; 17(2):189-200. · 3.39 Impact Factor
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HPB 01/2011; 13:670-674. · 1.60 Impact Factor
