Mechanisms of regenerative preconditioning in pigs with subtotal hepatectomies.

BACKGROUND: Portal vein occlusion shortly before extended hepatic resections has hepatoprotective properties, but its molecular effects have not been elucidated. We characterized the impact of regenerative preconditioning by portal vein embolization (PVE) on hepatic energy metabolism and cytokine expression. MATERIALS AND METHODS: About 90% hepatectomies were performed in normal pigs (Control) and in pigs that underwent a PVE 24 h before the surgery (n = 10/group). Blood biochemistry and coagulation, liver damage, liver function (ICG), hepatic content of adenine nucleotides, and hepatic expression of inflammatory mediators (RT-PCR and WB) were determined before the hepatectomy, 15 min, and 24 h later. RESULTS: All PVE and hepatectomies were successfully accomplished. The 90% hepatectomy resulted in: Immediate reduction of ATP, leading to persistent decreases of energy load and ATP/ADP ratio up to the 24-h time-point; and pro-inflammatory expression profile of cytokines in the remnant liver. Prior performance of PVE attenuated the bioenergetic alterations and prevented many of the changes in hepatic cytokine expression. CONCLUSIONS: Regenerative preconditioning by PVE improved hepatic energy metabolism and modulated inflammatory mediators in the remnant liver in pigs undergoing major hepatectomies, potentially contributing to its hepatoprotective effects.

INTRODUCCIÓN: la oclusión de la vena porta precoz antes de hepatectomías extendidas tiene propiedades hepatoprotectoras, pero sus efectos moleculares no se han aclarado. Caracterizamos el impacto del preacondicionamiento regenerativo por embolización de la vena porta (PVE) sobre el metabolismo energético hepático y la expresión de citocinas. MATERIALES Y MÉTODOS: Realizamos hepatectomías del 90% en cerdos (Control) y en cerdos sometidos a PVE 24 horas antes de la cirugía (n = 10/grupo). La bioquímica y la coagulación, el daño hepático, la función hepática (ICG), los nucleótidos de adenina y la expresión de mediadores inflamatorios (RT-PCR y WB) fueron determinado antes de la hepatectomía, quince minutos y 24 horas después. RESULTADOS: Las PVE y las hepatectomías se realizaron con éxito. La hepatectomía del 90% resultó en: una reducción del ATP, lo que disminuye la carga energética y la relación ATP/ADP a las 24 horas; y en la expresión de citocinas proinflamatorias. La realización previa de PVE atenuó las alteraciones bioenergéticas y evitó muchos de los cambios en la expresión de citocinas. CONCLUSIONES: El preacondicionamiento regenerativo con PVE mejoró el metabolismo energético y moduló los mediadores inflamatorios en el hígado remanente en cerdos sometidos a hepatectomías subtotales, contribuyendo potencialmente a sus efectos hepatoprotectores.

Comprehensive Characterization of a Porcine Model of The "Small-for-Flow" Syndrome.

INTRODUCTION: The term "Small-for-Flow" reflects the pathogenetic relevance of hepatic hemodynamics for the "Small-For-Size" syndrome and posthepatectomy liver failure. We aimed to characterize a large-animal model for studying the "Small-for-Flow" syndrome. METHODS: We performed subtotal (90%) hepatectomies in 10 female MiniPigs using a simplified transection technique with a tourniquet. Blood tests, hepatic and systemic hemodynamics, and hepatic function and histology were assessed before (Bas), 15 min (t-15 min) and 24 h (t-24 h) after the operation. Some pigs underwent computed tomography (CT) scans for hepatic volumetry (n = 4) and intracranial pressure (ICP) monitoring (n = 3). Postoperative care was performed in an intensive care unit environment. RESULTS: All hepatectomies were successfully performed, and hepatic volumetry confirmed liver remnant volumes of 9.2% [6.2-11.2]. The hepatectomy resulted in characteristic hepatic hemodynamic alterations, including portal hyperperfusion, relative decrease of hepatic arterial blood flow, and increased portal pressure (PP) and portal-systemic pressure gradient. The model reproduced major diagnostic features including the development of cholestasis, coagulopathy, encephalopathy with increased ICP, ascites, and renal failure, hyperdynamic circulation, and hyperlactatemia. Two animals (20%) died before t-24 h. Histological liver damage was observed at t-15 min and at t-24 h. The degree of histological damage at t-24 h correlated with intraoperative PP (r = 0.689, p = 0.028), hepatic arterial blood flow (r = 0.655, p = 0.040), and hepatic arterial pulsatility index (r = 0.724, p = 0.066). All animals with intraoperative PP > 20 mmHg presented liver damage at t-24 h. CONCLUSION: The present 90% hepatectomy porcine experimental model is a feasible and reproducible model for investigating the "Small-for-Flow" syndrome.

Preconditioning by portal vein embolization modulates hepatic hemodynamics and improves liver function in pigs with extended hepatectomy.

BACKGROUND: Portal vein embolization is performed weeks before extended hepatic resections to increase the future liver remnant and prevent posthepatectomy liver failure. Portal vein embolization performed closer to the operation also could be protective, but worsening of portal hyper-perfusion is a major concern. We determined the hepatic hemodynamic effects of a portal vein embolization performed 24 hours prior to hepatic operation. METHODS: An extended (90%) hepatectomy was performed in swine undergoing (portal vein embolization) or not undergoing (control) a portal vein embolization 24 hours earlier (n = 10/group). Blood tests, hepatic and systemic hemodynamics, hepatic function (plasma disappearance rate of indocyanine green), liver histology, and volumetry (computed tomographic scanning) were assessed before and after the hepatectomy. Hepatocyte proliferating cell nuclear antigen expression and hepatic gene expression also were evaluated. RESULTS: Swine in the control and portal vein embolization groups maintained stable systemic hemodynamics and developed similar increases of portal blood flow (302 ± 72% vs 486 ± 92%, P = .13). Portal pressure drastically increased in Controls (from 9.4 ± 1.3 mm Hg to 20.9 ± 1.4 mm Hg, P < .001), while being markedly attenuated in the portal vein embolization group (from 11.4 ± 1.5 mm Hg to 16.1 ± 1.3 mm Hg, P = .061). The procedure also improved the preservation of the hepatic artery blood flow, liver function, and periportal edema. These effects occurred in the absence of hepatocyte proliferation or hepatic growth and were associated with the induction of the vasoprotective gene Klf2. CONCLUSION: Portal vein embolization preconditioning represents a potential hepato-protective strategy for extended hepatic resections. Further preclinical studies should assess its medium-term effects, including survival. Our study also supports the relevance of hepatic hemodynamics as the main pathogenetic factor of post-hepatectomy liver failure.

Single-Institution Multidisciplinary Management of Locoregional Oligo-Recurrent Pelvic Malignancies: Long-Term Outcome Analysis.

PURPOSE: The aim of this study was to analyze long-term outcomes and prognostic factors associated with survival in patients with locoregional oligo-recurrent (LROR) pelvic malignancies treated in a multimodal protocol. METHODS: Patients with an histologic diagnosis of LROR pelvic cancer (rectal 50 %, gynecological 50 %) with absence of distant metastases, undergoing surgery with radical intent and intraoperative radiotherapy (median dose 12.5 Gy) were considered eligible for participation in this study. Additionally, 48 % received external beam radiotherapy (EBRT) (median dose 50 Gy). RESULTS: From 1995 to 2012, a total of 143 patients from a single institution were analyzed. With a median follow-up time of 48 months (range 2-189), 5-year locoregional control (LRC), disease-free survival (DFS), and overall survival (OS) were 53, 44, and 46 %, respectively. On multivariate analysis, no EBRT treatment to the locoregional (p ≤ 0.001), R1 margin status (p = 0.03), time interval from primary tumor diagnosis to LROR <24 months (p = 0.05), and fragmentation in the resected specimen (p = 0.004) retained significance in relation to LRC. On multivariate analysis we found that only R1 margin status (p = 0.003), primary tumor diagnosis to LROR <24 months (p = 0.02), and high histological grade (p = 0.02) were significantly associated with OS. CONCLUSIONS: From this analysis emerges the fact that EBRT influences local control but, given the high risk of distant metastases, DFS remains modest. Margin status, tumor fragmentation, no EBRT to the LR, and time interval from primary tumor diagnosis to LROR are the dominant factors for subsequent locoregional recurrence (LRR). Accordingly, future prospective studies might be designed which adapt treatment according to the predicted risk of subsequent LRR.

Prognostic value of external beam radiation therapy in patients treated with surgical resection and intraoperative electron beam radiation therapy for locally recurrent soft tissue sarcoma: a multicentric long-term outcome analysis.

BACKGROUND: A joint analysis of data from centers involved in the Spanish Cooperative Initiative for Intraoperative Electron Radiotherapy was performed to investigate long-term outcomes of locally recurrent soft tissue sarcoma (LR-STS) patients treated with a multidisciplinary approach. METHODS AND MATERIALS: Patients with a histologic diagnosis of LR-STS (extremity, 43%; trunk wall, 24%; retroperitoneum, 33%) and no distant metastases who underwent radical surgery and intraoperative electron radiation therapy (IOERT; median dose, 12.5 Gy) were considered eligible for participation in this study. In addition, 62% received external beam radiation therapy (EBRT; median dose, 50 Gy). RESULTS: From 1986 to 2012, a total of 103 patients from 3 Spanish expert IOERT institutions were analyzed. With a median follow-up of 57 months (range, 2-311 months), 5-year local control (LC) was 60%. The 5-year IORT in-field control, disease-free survival (DFS), and overall survival were 73%, 43%, and 52%, respectively. In the multivariate analysis, no EBRT to treat the LR-STS (P=.02) and microscopically involved margin resection status (P=.04) retained significance in relation to LC. With regard to IORT in-field control, only not delivering EBRT to the LR-STS retained significance in the multivariate analysis (P=.03). CONCLUSION: This joint analysis revealed that surgical margin and EBRT affect LC but that, given the high risk of distant metastases, DFS remains modest. Intensified local treatment needs to be further tested in the context of more efficient concurrent, neoadjuvant, and adjuvant systemic therapy.

Intra-operative radiotherapy (IORT) in pancreatic cancer: joint analysis of the ISIORT-Europe experience.

PURPOSE: A joint analysis of data from five contributing centers within the ISIORT-Europe program was performed to investigate the main contributions of intra-operative radiotherapy (IORT) to the multidisciplinary treatment of pancreatic cancer. MATERIALS AND METHODS: Patients with a histologic diagnosis of carcinoma of the pancreas, with an absence of distant metastases, undergoing surgery with radical intent and IORT were considered eligible for participation in this study. RESULTS: From 1985 to 2006, a total of 270 patients were enrolled in the study from five European institutions. Surgery was performed in 91.5% of cases and complicated by adverse events in 59 cases. External radiotherapy (ERT) preceded surgery in 23.9% of cases. One-hundred and six patients received further ERT. After surgery + IORT, median follow-up was 96 months (range 3-180). Median local control was 15 months, 5-year local control was 23.3%. Median overall survival was 19 months, while 5-year survival was 17.7%. A significantly greater local control and survival were observed in patients undergoing preoperative radiotherapy (LC: median not reached; OS: median 30 months) compared to patients treated with postoperative ERT alone (LC: median 28 months; OS: median 22 months), and to patients submitted to IORT exclusively (LC: median 8 months; OS: median 13 months) (p < 0.0001). CONCLUSION: From this joint analysis emerges the fact that preoperative radiotherapy increases the effects of IORT in terms of local control and overall survival. The 5-year local control of 23.3% confirms the beneficial "sterilizing" effect of IORT on the tumor bed.

Prognostic factors for disease-free survival in patients with T3-4 or N+ rectal cancer treated with preoperative chemoradiation therapy, surgery, and intraoperative irradiation.

PURPOSE: Fluoropyrimidine-radiosensitizing agents in conjunction with preoperative radiotherapy have proven to induce tumor and nodal downstaging effects, sphincter preservation promotion, and mid-term favorable survival rates. Intraoperative electron beam radiation therapy may improve pelvic control in patients with locally advanced rectal cancer stages. Potential predictive factors for response and disease-free survival, with intense local multidisciplinary approach, are analyzed. METHODS AND MATERIALS: One hundred fifteen patients with rectal cancer were treated with oral 5-fluorouracil or Tegafur with preoperative radiotherapy, surgery, and intraoperative electron beam radiation therapy to identify potential pre- and on-treatment characteristics that might be of prognostic value for disease outcome. Univariate and multivariate analyses were performed. RESULTS: Older patients and those treated with Tegafur were more likely to achieve a major histologic response, categorized as persistence of minimal residual microscopic disease foci in the surgical specimen ("mic" response). Factors unfavorably associated with disease-free survival in the multivariate model were male gender and persistence of macroscopic disease in the rectal wall ("mac" response). Accordingly, 3-year disease-free survival rates in the groups of patients with 0, 1, or 2 of these risk factors were 100%, 81%, and 53%, respectively (p < 0.001). CONCLUSIONS: Females with an intense pathologic response (pT(mic) residue) to preoperative chemoradiotherapy have an excellent 3-year disease-free survival. This information might be of interest for stratification of patients in the development of adjuvant treatment trials.