Neither Isolated Hepatic Arterial Clamping nor Hepatic Arterial Ligation Induce Ischemic Type Biliary Lesions in Rats.

BACKGROUND Ischemic type biliary lesions (ITBL) is a troublesome complication after liver transplantation. Little is known about its pathogenesis and there is particularly little data about morphological alterations. Prolonged warm and cold ischemia time and reduced hepatic arterial perfusion are risk factors leading to ITBL. There are only a few animal models described in literature. Therefore, we examined the effects of 3 h of hepatic artery ischemia-reperfusion (3 h I/R) and hepatic arterial ligation (HAL), both combined with ligation of the peribiliary plexus (PBP). MATERIAL AND METHODS 3 h I/R was performed by clamping the hepatic artery with microvascular clamps for 3 h. HAL was performed by ligation of the hepatic artery. Both procedures were combined with stenting of the common bile duct with double ligation of the PBP. A sham group without clamping served as control. Serum activities of aspartate transaminase (AST) and alanine transaminase (ALT), direct and total bilirubin (DB/TB), and lactate dehydrogenase (LDH) were measured. Bile flow was analyzed and histological examinations of leukocyte infiltration (CAE), cell proliferation (PCNA), apoptotic cells (HE), and bile ducts morphology (CK7) were performed. Western blots of the vascular endothelial growth factor (VEGF) and caspase 3 were made to investigate vascular growth expression and apoptotic cell death. RESULTS 3 h I/R and HAL were associated with a significant hepatocellular injury and inflammation, shown through increased AST and ALT, leukocyte infiltration, and apoptotic cell death. An increase of bile ducts and a reduction of arteries/bile duct ratio after 30 days was observed in the 3 h I/R group and HAL, but no ITBL-typical bile duct necrosis, intrahepatic strictures, or dilatations of bile ducts occurred. CONCLUSIONS Morphological alterations in a rat animal model of 3 h I/R and HAL could be demonstrated. However, a model of intrahepatic biliary lesions could not be established through hepatic arterial ligation or through 3-h hepatic arterial ischemia and reperfusion.

Perigraft vascularization and incorporation of implanted Dacron prostheses are affected by rifampicin coating.

BACKGROUND: Prosthetic vascular grafts are increasingly implanted to replace damaged arteries. However, their microbial contamination is highly problematic and often results in devastating clinical complications. To reduce the risk of infection, Dacron grafts may be coated with rifampicin. In this experimental study we analyzed whether this coating affects the early tissue incorporation of the grafts. METHODS: Saline- and rifampicin-coated Dacron (Dacron-Rifamp) grafts were implanted into dorsal skinfold chambers of C57BL/6 mice (n = 8 per group) to study vascularization, inflammation, cell proliferation, and apoptosis at the implantation site using repetitive intravital fluorescence microscopy and immunohistochemistry over an observation period of 14 days. RESULTS: Implanted Dacron-Rifamp grafts exhibited a impaired vascularization, indicated by a significantly lower functional capillary density (85 ± 1 cm/cm2) compared with controls (113 ± 1 cm/cm2; P < .05). This was associated with a reduced number of Ki-67-positive proliferating cells (9.4% ± 1.1% vs 13.5 ± 0.4%; P < .05) and an increased number of cleaved caspase-3-positive apoptotic cells (2.7% ± 0.3% vs 1.3% ± 0.3%; P < .05) in the newly developing granulation tissue surrounding the implants. In addition, the neutrophilic (652 ± 84 mm2 vs 934 ± 117 mm2; P = .06), lymphatic (26 ± 6 mm2 vs 39 ± 9 mm2; P = .24) and macrophage response (177 ± 42 mm2 vs 233 ± 86 mm2; P = .57) was decreased by trend in the group with Dacron-Rifamp grafts. CONCLUSIONS: Our novel findings show that early perigraft vascularization and incorporation of implanted Dacron prostheses are affected by the rifampicin coating. Because rapid graft vascularization and incorporation are thought to reduce the risk of infection, the use of Dacron-Rifamp Dacron grafts for antibacterial prophylaxis should be reconsidered particularly in cases of elective arterial reconstruction in a noninfected environment.

Preconditioning by cilostazol protects against cold hepatic ischemia-reperfusion injury.

BACKGROUND: In liver transplantation, prolonged cold storage and post-transplant reperfusion are associated with endothelial inflammation, organ dysfunction, and graft failure. We herein studied whether cilostazol, a phosphodiesterase-3-inhibitor, attenuates post-ischemic liver injury after prolonged cold storage. MATERIAL AND METHODS: Sprague-Dawley rats were assigned to 5 groups (n=6 each): sham animals (cold storage time (CST): 1 h), vehicle-treated (NaCl 0.9%) controls (CST: 24 h), and animals receiving 0.1, 1.0, or 10.0 mg/kg body weight (BW) cilostazol pre-treatment (CST: 24 h). After organ explantation, all livers were stored at 4°C in HTK solution, followed by 60 min of reperfusion with 37°C Krebs Henseleit buffer in a non-recirculating ex situ system. Bile flow was measured to evaluate liver function. To analyze inflammation and morphology, liver tissue samples were taken and histology, immunohistochemistry, and Western blotting were conducted. RESULTS: In vehicle-treated controls, prolonged cold storage and warm reperfusion induced inflammation, organ dysfunction, and cell death. This was indicated by an increase of hepatocellular vacuolization, endothelial ICAM-1 expression, and apoptotic cell death compared to sham animals. Cilostazol pre-treatment protected against cold hepatic ischemia-reperfusion injury by preventing hepatocellular disintegration, ICAM-1-associated endothelial inflammation, and apoptotic death. CONCLUSIONS: Inhibition of PDE3 reduces endothelial cell activation and hepatocellular injury in cold ischemia/reperfusion of the liver.

Cilostazol improves hepatic blood perfusion, microcirculation, and liver regeneration after major hepatectomy in rats.

Major hepatectomy or small-for-size liver transplantation may result in postoperative liver failure. So far, no treatment is available to improve liver regeneration. Herein, we studied whether cilostazol, a selective phosphodiesterase III inhibitor, is capable of improving liver regeneration after major hepatectomy. Sprague-Dawley rats (n = 74) were treated with cilostazol (5 mg/kg daily) or a glucose solution and underwent either 70% liver resection or a sham operation. Before and after surgery, hepatic arterial and portal venous blood flow and hepatic microvascular perfusion were analyzed. Liver morphology, function, and regeneration were studied with histology, immunohistochemistry, western blotting, and bile excretion analysis. Cilostazol significantly increased hepatic blood flow and microcirculation before and after hepatectomy in comparison with sham-operated controls. This was associated with an elevation of hepatic vascular endothelial growth factor expression, an increase of hepatocellular proliferation, and an acceleration of liver regeneration. Furthermore, cilostazol protected the tissue of the remnant liver as indicated by an attenuation of hepatocellular disintegration. In conclusion, cilostazol increases hepatic blood perfusion, microcirculation, and liver regeneration after a major hepatectomy. Thus, cilostazol may represent a novel strategy to reduce the rate of liver failure after both extended hepatectomy and small-for-size liver transplantation.

Isoflurane does not protect from brain death-associated aggravation of cold hepatic ischemia-reperfusion injury.

BACKGROUND: Previous studies have shown that brain death aggravates cold ischemia-reperfusion injury in liver transplantation. Isoflurane, a volatile anesthetic, has been indicated to reduce warm hepatic ischemia-reperfusion injury. Herein, we studied in Sprague-Dawley rats whether isoflurane is capable of ameliorating brain death-associated aggravation of cold hepatic ischemia-reperfusion injury. MATERIAL AND METHODS: Brain-dead animals were treated for 30 min with isoflurane (MAC 1.5%; n=8). Animals without isoflurane treatment served as controls (n=8). Another 13 animals without induction of brain death served as sham controls. After a 4-h period portal venous blood perfusion, hepatic microcirculation and bile flow were determined. Livers were recovered and stored for 24 h in 4°C cold HTK solution, followed by reperfusion with 37°C Krebs-Henseleit-buffer for 60 min. Liver enzymes in the effluent and bile flow were analyzed. Hepatocellular morphology was determined by histology and immunohistochemistry. RESULTS: Brain death reduced portal venous blood perfusion and bile flow, induced heme oxygenase-1 (HO-1), and resulted in hepatocellular damage. Isoflurane treatment did not prevent the reduction of portal venous blood perfusion or bile flow or the induction of HO-1. Accordingly, isoflurane was not capable of reducing the hepatocellular injury. CONCLUSIONS: Isoflurane does not protect from brain death-associated aggravation of cold hepatic ischemia-reperfusion injury.

The phosphodiesterase 3 inhibitor cilostazol does not stimulate growth of colorectal liver metastases after major hepatectomy.

Liver failure after extended hepatectomy represents a major challenge in the surgery of hepatic colorectal metastasis. A previous study has indicated that inhibition of phosphodiesterase type 3 (PDE 3) stimulates liver regeneration. However, little is known whether PDE 3 inhibitors, such as cilostazol, also stimulate the growth of remnant metastases. Therefore, we herein studied the effect of cilostazol on engraftment, vascularization and growth of colorectal liver metastasis after major hepatectomy. WAG-rats underwent either major hepatectomy or sham operation. Metastases were induced by subcapsular implantation of 5 × 10(5) CC531-colorectal cancer cells. Animals were daily treated with cilostazol (5 mg/kg body weight) or glucose solution. Tumor growth was measured by high-resolution ultrasound at days 7 and 14. Tumor vascularization and tumor cell proliferation were determined by immunohistochemistry and western blotting. High-resolution ultrasound analysis in hepatectomized and non-hepatectomized animals showed that cilostazol does not stimulate tumor growth. Accordingly, the number of PCNA-positive tumor cells did not differ between cilostazol-treated animals and sham-treated controls. Interestingly, cilostazol reduced tumor vascularization in both hepatectomized and non-hepatectomized animals. This was indicated by a significantly lower number of platelet-endothelial cell adhesion molecule (PECAM-1)-positive cells in tumors of cilostazol-treated animals compared to sham-treated controls. The PDE 3 inhibitor cilostazol does not stimulate the growth of colorectal metastases during liver regeneration after major hepatectomy.

Successful management of postoperative necrotizing pancreatitis after infrarenal abdominal aortic aneurysm repair.

We present a case of severe necrotizing pancreatitis that developed after elective repair of an abdominal aortic aneurysm. Surgeons are confronted in cases of postoperative acute pancreatitis with the dilemma of potential intraabdominal infection and the high risk of a subsequent infection of the retroperitoneal synthetic material. The therapeutic options range from a restrictive regime to radical necrosectomy and multivisceral resection.

Silver acetate coating promotes early vascularization of Dacron vascular grafts without inducing host tissue inflammation.

BACKGROUND: Silver acetate is frequently used as an antimicrobial coating of prosthetic vascular grafts. However, the effects of this coating on the early inflammatory and angiogenic host tissue response still remain elusive. Therefore, the aim of the present in vivo study was to analyze the biocompatibility and vascularization of silver acetate-coated and uncoated vascular grafts during the initial phase after implantation. METHODS: Two different prosthetic vascular grafts (ie, uncoated Dacron and silver acetate-coated Dacron Silver) were implanted into the dorsal skinfold chamber of C57BL/6 mice (n = 8 per group) to study angiogenesis and leukocytic inflammation at the implantation site by means of repetitive intravital fluorescence microscopy over a 14-day period. At the end of the in vivo experiments, collagen formation, apoptosis, and cell proliferation were analyzed in the newly developed granulation tissue surrounding the implants by histology and immunohistochemistry. RESULTS: During the initial 14 days after implantation, Dacron Silver exhibited an improved vascularization, as indicated by a significantly increased functional capillary density compared with Dacron. This was not associated with a stronger leukocytic inflammatory host tissue response to the implants. Moreover, silver acetate coating did not affect collagen formation, apoptosis, and cell proliferation at the implantation site. CONCLUSIONS: Silver acetate coating of prosthetic vascular grafts improves their early vascularization without inducing severe inflammatory side effects. Accordingly, this material modification crucially contributes to an improved incorporation of the implants into the host tissue, which may decrease the risk of vascular graft infection.

Long term follow up for incisional hernia after severe secondary peritonitis-incidence and risk factors.

BACKGROUND: In patients with secondary peritonitis, infections of the abdominal cavity might render the abdominal wall susceptible to secondary complications such as incisional hernia (IH). METHODS: One hundred ninety-eight patients treated for secondary peritonitis underwent midline laparotomy. Ninety-two surviving patients accessible to clinical follow-up were examined for the occurrence of IH, and risk factors at the time of surgery or during follow-up were determined. RESULTS: During a median follow-up period of 6 years, 54.3% of the patients developed IHs. A high body mass index, coronary heart disease, intense blood loss, requirement for intraoperative or postoperative transfusions, and small bowel perforation as a source of peritonitis were associated with IH. CONCLUSIONS: IH occurs quite frequently after surgery for secondary peritonitis. Preexisting risk factors for IH and intraoperative blood loss or requirement for blood transfusions were correlated with the development of IH. Interestingly, surgical technique was not correlated with the development of IH in this series.

Staged lavage versus single high-volume lavage in the treatment of feculent/purulent peritonitis: a matched pair analysis.

BACKGROUND: Spontaneous and iatrogenic secondary peritonitis remain to have a mortality of 10-30% and significant socioeconomic impact in survivors and especially non-survivors. Data on the most cost-effective treatment are lacking. We therefore studied outcome and resource utilization in a homogeneous cohort of patients with secondary fecal or purulent peritonitis undergoing surgery with source control and two different types of abdominal lavage. METHODS: Thirty-one consecutive patients with secondary feculent or purulent peritonitis of the lower gastrointestinal tract underwent a single high-volume lavage. That cohort was matched with 31 patients with the same source, extent, and quality of peritonitis treated by source control and staged lavage (intermittent lavage). RESULTS: Patients in both groups were comparable in gender distribution, age, comorbidity, source, extent, and severity of peritonitis with the history of intestinal perforation in the single high-volume lavage group being significantly higher than in the intermittent lavage group (2.0 +/- 1.7 vs. 1.1 +/- 0.8d; p = 0.008). Patients in the single high-volume lavage group had significantly less operations, thus requiring significantly less operation time (OR-time), intensive care unit (ICU)-requirement, ventilatory support, and inotropic support. CONCLUSION: Patients with secondary fecal or purulent peritonitis in at least two quadrants, undergoing a one step surgical repair including source control, primary anastomosis, and single high-volume lavage with more than 25 l have a comparable outcome to patients treated by staged lavage at significantly lower OR and ICU-utilization.

Surgery of liver metastasis in gynecological cancer - indication and results.

BACKGROUND: Liver surgery for patients with liver metastases from gynecological malignancies, an indicator of advanced cancer disease, has remained unclear in the literature. We therefore analyzed the potential survival benefit of patients with surgically resectable compared to unresectable liver metastases. PATIENTS AND METHODS: 43 patients who underwent surgery for liver metastases from gynecological cancers were included in our retrospective observational analysis. Overall survival was estimated according to the Kaplan-Meier method and compared with the log-rank test. RESULTS: Primary gynecological tumors were breast (n = 27), ovarian (n = 8), and uterine (n = 8) cancers. Solely exploratory laparotomy was performed in 13 patients who served as controls. Whereas the perioperative mortality was 0%, minor complications occurred in 18.7%. The overall survival of all patients undergoing liver resection was significantly higher (p < 0.05) than that of patients with unresectable metastases. Subgroup analyses showed that particularly patients with respectable liver metastases from breast cancer had a significantly higher (50%) 5-year survival compared to patients with only an exploratory laparotomy. CONCLUSION: In selected patients, liver resection of metastases from gynecological cancers can achieve a survival benefit similar to that of patients with colorectal cancer metastases.

Post-hypoxic cellular disintegration in glycine-preserved renal tubules is attenuated by hydroxyl radical scavengers and iron chelators.

BACKGROUND: Cellular stress during reoxygenation is a common phenomenon in solid organ transplantation and is characterized by production of reactive oxygen species. Herein, we studied in isolated tubular segments of rat kidney cortex the impact of oxygen radical scavengers and an iron chelator on post-hypoxic recovery. METHODS: Tubules, suspended in Ringer's solution containing 5 mM glycine, underwent 30 min hypoxia and 60 min reoxygenation. Untreated tubules served as controls. Hypoxia-reoxygenation injury was measured by membrane leakage, lipid peroxidation and cellular functions. In hypoxia-reoxygenated-isolated tubular segments, protective effects of different scavengers and of the iron chelator deferoxamine on hypoxia-reoxygenation injury were analyzed. RESULTS: Scavengers protected isolated tubular segments from hypoxia-reoxygenation-induced cellular disintegration and dysfunction. Deferoxamine was found to exert the most distinct protection. It was further found to exert a dose-dependent protection on hypoxia-reoxygenation damage in isolated tubular segments, which was critically mediated by chelating tissue and bond iron. CONCLUSIONS: Our data demonstrate that radical scavengers effectively protect from hypoxia-reoxygenation injury in isolated tubular segments and that the iron chelator deferoxamine is especially a potent inhibitor of iron ion-mediated hypoxia-reoxygenation damage. Thus, inclusion of this iron chelator in organ storage solutions might improve post-transplant organ function and protect from reperfusion injury.