High-Dose Mitomycin C in Isolated Hyperthermic Liver Perfusion for Unresectable Liver Metastases

In order to reduce systemic side effects and increase intrahepatic mitomycin C (MMC) concentrations, isolated hyperthermic liver perfusion (IHLP) has been performed using MMC. This article describes the pharmacokinetics of MMC in IHLP and presents our clinical experience with its use in six patients suffering from unresectable liver metastases. Primary tumors consisted of colorectal carcinomas in three cases, breast cancer in two, and a choroidal melanoma in one. Dosages of MMC varied between 0.5 and 1.0 mg MMC/kg body weight. MMC was added as a bolus directly into the extracorporeal circuit. Intrahepatic temperature was elevated to 40.0-41.0°C by hyperthermic perfusion. MMC concentrations were measured in peripheral blood (preperfusion, then at 5, 30, and 55 min during perfusion, and finally at 5 and 60 min and 6 and 24 h after perfusion) and in recirculating perfusate (5, 30, and 55 min). While markedly elevated MMC concentrations (maximum 6290 ng/mL) were found in the liver perfusate, systemic concentrations remained low (maximum 45 ng/mL), indicating no considerable leakage. MMC concentrations in the perfusate constantly decreased during perfusion. After rinsing with 1500 mL saline, a mean concentration of 52.5 f 33 ng MMC/mL was measured in the washout from 5 patients. In 1 patient with a colorectal carcinoma, MMC concentrations in the perfusion medium were 10-fold and in the plasma 2-fold higher than in the other patients. This high MMC concentration caused severe intrahepatic vascular damage and finally led to the patient's death. In conclusion, IHLP and intrahepatic perfusion with MMC resulted in a high response of hepatic tumors. Systemic exposure of MMC can be reduced effectively by isolated perfusion. However, hepatic toxicity of MMC must be considered.     

Evaluation of a Modified HTK Solution Containing the New Iron Chelator LK 614 in an Isolated Rat Liver Perfusion Model

Background: Cold storage-induced injury to donor organs remains a persistent problem in transplantation medicine. We here evaluated a modified HTK solution including, among others, a new, membrane-permeable iron chelator, LK 614, in the isolated perfused rat liver model. Methods: Rat livers were stored at 4°C for 24 hr in modified HTK solution, in modified HTK solution with LK 614 or in traditional HTK solution, and reperfused for 60 min at 37°C with Krebs-Henseleit buffer (KH buffer). Bile secretion and lactate dehydrogenase (LDH) release into the perfusate were measured, and hepatic microcirculation evaluated optically after the addition of trypan blue to the perfusate. Biopsies were evaluated by a pathologist blinded to the experimental conditions. Results: Compared with HTK-preserved livers, LDH leakage was significantly lower and bile secretion significantly higher in the modified HTK solution with the iron chelator (both p <. 05), while values for the modified solution without the iron chelator were in between (no significant difference to either of the two other solutions). The hepatic microcirculation was also preserved best in livers stored in the modified HTK solution with LK 614. Histomorphological investigation confirmed the improved preservation in the modified HTK solution with LK 614. Conclusions: These results suggest that livers might be better preserved in modified HTK solution containing the iron chelator LK 614 (and also, but less so, in the modified solution without the iron chelator) than in the original HTK solution, and such a modified solution should now be evaluated in an animal model of liver transplantation.     

Isolated Hypoxic Hepatic Perfusion with Retrograde Outflow in Patients with Irresectable Liver Metastases; A New Simplified Technique in Isolated Hepatic Perfusion

Background Isolated hepatic perfusion with high-dose chemotherapy is a treatment option for patients with irresectable metastases confined to the liver. Prolonged local control and impact on survival have been claimed. Major drawbacks are magnitude and costs of the procedure. We developed an isolated hypoxic hepatic perfusion (IHHP) with retrograde outflow without the need for a heart-lung machine. Patients and Methods Twenty-four consecutive patients with irresectable metastases of various origins were treated. IHHP inflow was via the hepatic artery, outflow via the portal vein with occlusion of the retrohepatic caval vein. Radiolabeled albumine was used for leakage monitoring. Melphalan was used at 1–2 mg/kg. A 25-minute perfusion period was followed by a complete washout. Local and systemic melphalan concentrations were determined. Results Compared with oxygenated classical IHP, the IHPP procedure reduced operation time from >8 h to 4 hours, blood loss from >4000 to 900 cc and saved material and personnel costs. Leakage was 0% with negligible systemic toxicity and 0% perioperative mortality. Tumor response: complete response (CR) in 4%, partial response (PR) in 58%, and stable disease (SD) in 13%. Median time to progression was 9 months (2–24 months); pharmacokinetics demonstrated intrahepatic melphalan concentrations more than 9 fold higher than postperfusion systemic concentrations. Conclusions IHPP is a relatively simple procedure with reduced costs, reduced blood loss, no mortality, limited toxicity, and response rates comparable to classic IHP. The median duration of 9 months of tumor control should be improved. Hereto, vasoactive drugs, will be explored in further studies.     

Development of a Bioartificial Liver Using Isolated Hepatocytes

Abstract: Severe liver disease is very often life-threatening and dramatically diminishes quality of life. Liver support systems based on detoxification alone have been proved ineffective because they cannot correct biochemical disorders. An effective artificial liver support system should be capable of carrying out the liver's essential processes, such as synthetic and metabolic functions, detoxification, and excretion. It should be capable of sustaining patients with fulminant hepatic failure, preparing patients for liver transplantation when a donor liver is not readily available (i.e., bridge to transplantation), and improving the survival and quality of life for patients for whom transplantation is not a therapeutic option. Recent advances in cell biology, tissue culture techniques, and biotechnology have led the way for the potential use of isolated hepatocytes in treating an array of liver disorders. Isolated hepatocytes may be transplanted to replace liver-specific deficiencies or as an important element of an auxiliary hybrid, bioartificial extracorporeal liver support device, which are important therapeutic applications for treating severe liver disease. Recently, several hepatocyte-based liver support systems have been proposed. Although there is no current consensus on its eventual design configuration, the hollow fiber hepatocyte bioreactor shows the greatest promise. Furthermore, application of tissue engineering technology, based on cellsurface interaction studies proposed by our group and others, has enhanced interest in the development of highly efficient hybrid, bioartificial, liver support devices.     

Effects of Pyridoxalated Hemoglobin Polyoxyethylene Conjugate and Stroma Free Hemoglobin on Pulmonary Vascular Responsiveness to Vasoactive Substances in Isolated Perfused Rat Lungs

We examined the effects of pyridoxalated hemoglobin polyoxyethylene conjugate (PHP) and stroma free hemoglobin (SFH) on vascular responsiveness to various vasoactive substances in isolated perfused rat lungs. The lungs isolated from rats were perfused with 6% PHP, 6% SFH, or 6% hydroxyethylstarch (HES) solution, and the effects of intrapulmonary arterial injection of norepinephrine (NE), angiotensin II (ANG-II), acetylcholine (ACh), and nitroglycerin (NG) were examined by measuring perfusion pressure. NE and ANG-II produced a dose-dependent increase in perfusion pressure in all groups. The NE response in the PHP- or SFH-perfused group was significantly larger than that in the HES-perfused one. ACh decreased perfusion pressure in both PHP- and HES-perfused groups but increased perfusion pressure in the SFH-perfused group. NG decreased perfusion pressure in all groups. Present results indicate that pulmonary arterial responses to endothelium-derived relaxing factor (EDRF) induced by ACh would not be affected in the presence of PHP.     

Effects of Pyridoxalated Hemoglobin Polyoxyethylene Conjugate and Stroma-free Hemoglobin on Renal Vascular Responsiveness to Vasoactive Substances in Isolated Perfused Rat Kidney

Abstract: The effects of pyridoxalated hemoglobin polyoxyethylene conjugate (PHP) and stroma-free hemoglobin (SFH) on vascular responsiveness to various vasoactive substances were examined in isolated perfused rat kidneys. The kidneys isolated from rats were perfused with 6% PHP, 6% SFH, and 6% hydroxyethylstarch (HES) solution at a constant flow rate. Vascular responsiveness to acetylcholine (ACh), nitroglycerin (NG), norepinephrine (NE), and angiotensin-II (ANG-II) was examined by measuring the perfusion pressure (PP). Effects of inhibition of endothelium-derived relaxing factor (EDRF) by N^G-monomethyl L-arginine (L-NMMA) on NE-induced and ANG-II-induced renal vascular responses were examined. ACh and NG induced a dose-dependent decrease in perfusion pressure (PP) in all groups. NE and ANG-II induced an increase in PP in all groups, but NE-induced and ANG-II-induced responses in the PHP-perfused and SFH-perfused groups were significantly larger than those in the HES-perfused group. L-NMMA did not alter vascular responsiveness to NE and ANG-II. These results indicate that PHP and SFH do not inhibit EDRF induced by ACh, but hemoglobin moiety per se does augment the vascular responsiveness to NE and ANG-II in the isolated perfused rat kidney.     

Isolated Hepatic Perfusion for the Treatment of Patients With Colorectal Cancer Liver Metastases After Irinotecan-Based Therapy

Background Irinotecan given with 5-fluorouracil and leucovorin is currently used as first-line therapy for patients with metastatic colorectal cancer (CRC). However, the response duration is <1 year, and second-line systemic chemotherapy has limited efficacy. We analyzed the efficacy of isolated hepatic perfusion (IHP) for patients with progressive CRC liver metastases after irinotecan.Methods Between March 1993 and February 2003, 124 patients with CRC liver metastases underwent IHP on institutional review board–approved protocols. The overall treatment mortality was 4% (5 of 124). Twenty-five patients (10 women and 15 men; mean age, 53 years) were identified who had progressive liver metastases by carcinoembryonic antigen, imaging studies, or both after irinotecan. A 1-hour hyperthermic IHP (mean hepatic temperature, 40.0°C) with melphalan 1.5 mg/kg (mean total dose, 100 mg) was administered via laparotomy. Perfusion with an oxygenated extracorporeal circuit was established with inflow via a cannula in the gastroduodenal artery and common hepatic artery inflow occlusion. Outflow was via a cannula in an isolated segment of the inferior vena cava. During IHP, portal and inferior vena caval flow were shunted to the axillary vein. Patients were assessed for radiographical response, recurrence pattern, and survival.Results The mean number of prior irinotecan cycles in 25 patients was 6 (range, 2–14), and it was given primarily as second-line therapy. The median number of liver metastases before IHP was 10 (range, 1–50), and the median percentage of hepatic replacement by tumor was 25%. The mean operative time was 9 hours (range, 6–12 hours), and the median hospital stay was 11 days (range, 8–76 days). There was 1 complete response and there were 14 partial responses in 25 patients (60%), with a median duration of 12 months (range, 5–35 months). Disease progressed systemically in 13 of 25 patients at a median of 5 months (range, 3–16 months). The median overall survival was 12 months (range, 1–47 months), and the 2-year survival was 28%.Conclusions For patients with progressive CRC liver metastases after irinotecan, IHP has good efficacy in terms of response rate and duration. Continued evaluation of IHP with melphalan as second-line therapy in this clinical setting is justified.     

Development of an Isolated Perfusion Circuit with Double Bypass Using Automatic Blood Pumps

Abstract: Isolated perfusion of the liver is a useful and promising therapeutic method for various hepatic diseases. However, conventional techniques using a roller pump require a large priming volume and cannot run at the low flow rate without complications. These disadvantages do not allow the use of conventional techniques in smaller pediatric patients. The authors solved these problems successfully for the first time by using unique sac-type air-driven automatic blood pumps with an oxygen-ator primed with a blood volume of 65 ml in the total circuit. The usefulness of these blood pumps for liver perfusion was evaluated in small animals weighing 3.5–6.0 kg. A hepatic perfusion circuit was established between the portal vein and the inferior vena cava. The blood pumps worked well without any trouble, and stable flow could be maintained. No hepatocellular damage or anaerobiosis of the liver was observed at a hepatic perfusion flow rate of 20 ml/min/kg. Isolated liver perfusion using these blood pumps can be applied in infants and young children.     

Correlation Between Melphalan Pharmacokinetics and Hepatic Toxicity Following Hyperthermic Isolated Liver Perfusion for Unresectable Metastatic Disease

Background In the present work, we report on the results of our pilot study of hyperthermic isolated hepatic perfusion (IHP) with melphalan alone for patients with unresectable metastatic liver tumors refractory to conventional treatments, with particular regard to the correlation between pharmacokinetic findings and hepatic toxicity. Patients and methods Inclusion criteria were unresectable liver metastases, hepatic parenchyma replacement ≤50%, normal liver function, and previous failure of at least one conventional treatment. IHP was performed under hyperthermic conditions with melphalan (1.5 mg/kg body weight). Completeness of vascular isolation of the liver and drug distribution volumes of the perfusion circuit were assessed by a radiolabeled albumin-based method. Drug concentrations in perfusate and plasma were measured by means of high-performance liquid chromatography (HPLC). Results Twenty patients with unresectable liver metastases underwent IHP. No intraoperative mortality occurred. Treatment-related systemic toxicity was minimal and reversible. Three patients (15%) experienced grade 4 hepatic toxicity and died due to liver failure and subsequent multiorgan failure. Other six patients had significant (grade 3–4) but transitory hepatic toxicity. Complete and partial responses were observed in three and nine out of 17 evaluable patients, respectively (overall response rate = 70%). The pharmacokinetics study showed a 3% mean perfusate-to-plasma drug leakage (range 1–6%). Logistic regression analysis showed that drug concentration in the perfusate circuit, but not preoperative tests, significantly and independently correlated with hepatic toxicity (P = 0.028). Conclusions Following melphalan-based IHP, objective tumor regression could be observed in a remarkable percentage of patients refractory to standard treatments. However, hepatic toxicity and related mortality were significant. Our findings suggest that drug dosage personalization based on the measurement of drug distribution volumes might minimize hepatic toxicity. Presented at the 59th Annual Cancer Symposium of the Society of Surgical Oncology, San Diego, California, USA, 23–26 March 2006     

Isolated Limb Infusion for In-Transit Malignant Melanoma of the Extremity: A Well-Tolerated but Less Effective Alternative to Hyperthermic Isolated Limb Perfusion

Background  Isolated limb infusion (ILI) is a recently described minimally invasive technique developed in Australia for delivering regional chemotherapy. This study examined the efficacy and toxicity of ILI, compared to hyperthermic isolated limb perfusion (HILP), in treating extremity in-transit melanoma. Methods  Variables from a prospective single institution database of 120 regionally treated melanoma patients (1995–2007) were compared using chi-square analysis. This included 61 consecutive ILI treatments in 58 patients and 59 HILP treatments in 54 patients. Response was defined at 3 months using the response evaluation criteria in solid tumors (RECIST). ILI was performed using melphalan (LPAM) and dactinomycin for 30 min after limb temperature reached 37°C. HILP was performed using LPAM for 60 min after limb temperature reached 38.5°C. Results  For ILI (n = 61), the complete response (CR) rate was 30%, the partial response (PR) rate was 14%, and there was no response (NR) in 56% of patients. The median duration of CR was 12 months and 18% of patients experienced (grade ≥3) toxicity. HILP (n = 59) was associated with a better (P < 0.001) response rate (CR 57%, PR 31%, and NR 12%) however, more patients (32%) experienced grade ≥3 toxicity (P = 0.037). The dose of LPAM was corrected for ideal body weight (IBW) in 40 out of 61 ILI procedures, and 13 of 59 HILP procedures. This dosing modification was associated with decreased toxicity (P = 0.024) without diminishing response. Conclusion  ILI was found to be a well-tolerated alternative to HILP. While ILI does not appear to be as effective as HILP, it does seem to be associated with less morbidity. Presented in part at the Society of Surgical Oncology’s 61st annual Cancer Symposium, March 13–16, 2008. Chicago, IL.     

Rescue of the Cold Preserved Rat Liver by Hypothermic Oxygenated Machine Perfusion

The aim of the study was to investigate whether hypothermic oxygenated liver perfusion after cold liver preservation resuscitated metabolic parameters and whether this treatment had a benefit for liver viability upon reperfusion.
We preserved rat livers either by cold storage (UW) for 10 h, or by perfusion for 3 h (oxygenated modified UW) after 10 h cold storage. We assessed viability of livers after preservation and after ischemic rewarming + normothermic reperfusion ex vivo . Ten hour cold storage reduced mitochondrial cytochrome oxidase and metabolically depleted the livers. Oxygenated perfusion after cold storage resulted in uploaded cellular energy charge and oxidized mitochondrial cytochrome oxidase. Reperfusion after 10 h cold storage increased formation of superoxid anions, release of cytosolic LDH, lipid peroxidation, caspase activities and led to disruption of sinusoidal endothelial cells. In contrast, reperfusion after 10 h cold storage + 3 h hypothermic oxygenated perfusion resulted in no changes of lipid peroxidation, bile flow, energy charge, total glutathione, LDH release and of caspase activation, as compared to fresh resected livers.
This study demonstrates, that a metabolically depleted liver due to cold storage can be energy recharged by short-termed cold machine perfusion. The machine perfused graft exhibited improved viability and functional integrity.     

A preservation solution with polyethylene glycol and calcium: a possible multiorgan liquid

The addition of polyethylene glycol (PEG) to hepatocyte storage medium is known to decrease lipid peroxidation and swelling and to protect the cell cytoskeleton from cold. We therefore decided to investigate the effect of substituting PEG for hydroxyethyl starch (HES) in an extracellular-like UW solution, with and without Ca++, on rat liver preservation. Isolated perfused rat livers were used to assess graft injury after 24h of cold storage. Four groups of preserved livers ( n=6 for each group) were compared to controls (non preserved livers, n=11). For this purpose, Belzer solution (K+-UW, group 1) was stepwise modified. Group 2 (Na+-UW) was treated with the same liquid, however with inverted concentrations of Na+ and K+. Group 3 was preserved in the first experimental solution (EPS-1) with Ca++ (0.5mM) added to the Na+-UW solution. In the EPS-2 (group 4), PEG-35 (0.03mM) was substituted for HES. The last group, EPS-3 (group 5) was treated with the same compounds as EPS-2, but without Ca++. After 24h of cold storage and 120min normothermic reperfusion, there was no statistical difference in transaminases (ALT and AST) release between the control and the Na+-UW groups. Furthermore, rat livers preserved in Na+-UW solution released less ( P<0.05) ALT and AST and excreted more ( P<0.05) indocyanine green (ICG) than livers preserved in K+-UW solution. The addition of 0.5mM Ca++ to Na+-UW solution (EPS-1) dramatically increased ( P<0.05) parenchymal (ALT, AST) and non parenchymal (creatine kinase-BB) cellular injury. The substitution of PEG (0.03mM) for HES (EPS-2) reduced ( P<0.05) membrane injuries due to Ca++ while bile flow was statistically increased ( P<0.05). Finally, the omission of Ca++ from EPS-2, that is EPS-3, has no statistically significant effect on the studied parameters. PEG effectively protected the rat liver grafts from the onset of hypothermic ischemia-reperfusion and Ca++ damages and thus may be a valuable additive to preservation solutions.     

Evaluation of parenchymal and nonparenchymal cell injury after different conditions of storage and reperfusion

We used the isolated perfused rat liver model (IPRL) to assess parenchymal and nonparenchymal cell integrity after different conditions of storage and reperfusion. Two studies were performed. In study 1, the IPRL was applied to evaluate the effects of 30 min of normothermic reperfusion with Elohes solution, enriched William's medium (Wif), or Carolina rinse solution (CRS) following 24 h of cold preservation in high-K⁺ or high-Na⁺ UW solution. As indicated by creatine kinase-BB (CK-BB) release, reperfusion with CRS provided greater protection of endothelial cells after storage in high-K⁺ UW solution than after storage in high-Na⁺ UW solution. In study 2, livers were cold-preserved (24 h, 4 °C) in either high-K⁺ or high-Na⁺ UW solution, then flushed with either CRS or Wif solution at room temperature before reperfusion (120 min, 37 °C) with 5 % albumin-William's medium E. There was no statistical difference between the rinse solutions for bile flow and transaminases release. However, CRS improved bile indocyanine green excretion, which is known to be a marker of parenchymal and nonparenchymal cell integrity. Therefore, we can assume that this rinse solution protects rat liver grafts from reperfusion-induced microvascular damage. Received: 29 December 1997 Received after revision: 31 March 1998 Accepted: 15 April 1998     

Impact of Subnormothermic Machine Perfusion Preservation in Severely Steatotic Rat Livers: A Detailed Assessment in an Isolated Setting

The current drastic shortage of donor organs has led to acceptance of extended‐criteria donors for transplantation, despite higher risk of primary nonfunction. Here, we report the impact of subnormothermic machine perfusion (SMP) preservation on the protection of >50% macrosteatotic livers. Dietary hepatic steatosis was induced in Wistar rats via 2‐day fasting and subsequent 3‐day re‐feeding with a fat‐free, carbohydrate‐rich diet. This protocol induces 50–60% macrovesicular steatosis, which should be discarded when preserved via cold storage (CS). The fatty livers were retrieved and preserved for 4 h using either CS in histidine‐tryptophan‐ketoglutarate or SMP in polysol solution. Graft functional integrity was evaluated via oxygenated ex vivo reperfusion for 2 h at 37°C. SMP resulted in significant reductions in not only parenchymal alanine aminotransferase (p < 0.001), but also mitochondrial glutamate dehydrogenase (p < 0.001) enzyme release. Moreover, portal venous pressure (p = 0.047), tissue adenosine triphosphate (p = 0.001), bile production (p < 0.001), high‐mobility group box protein‐1 (p < 0.001), lipid peroxidation, and tissue glutathione were all significantly improved by SMP. Electron microscopy revealed that SMP alleviated deleterious alterations of sinusoidal microvasculature and hepatocellular mitochondria, both of which are characteristic disadvantages associated with steatosis. SMP could protect 50–60% macrosteatotic livers from preservation/reperfusion injury, and may thus represent a new means for expanding available donor pools.     

二袖套法大鼠原位肝移植手术方法的改进

目的：通过对二袖套法大鼠原位肝移植手术方法进行改进，提高大鼠肝移植动物模型的稳定性。方法：采用改良的二袖套法施行大鼠原位肝移植动物实验110例，观察术后并发症及24h、一周存活率。结果：袖套准备时间5—9min，24h存活率91．8％(101／110)，一周存活率为87．3％(96／110)。结论:改进的大鼠原位肝移植术操作简便，手术成功率高，重复性好，提高了大鼠肝移植动物模型的稳定性。     

Isolated Chemotherapeutic Perfusion of Pelvis as Neoadjuvant or Palliative Therapy for Advanced Cancer of the Rectum

Introduction Previously irradiated recurrent rectal cancer is a formidable patient threat with limited treatment options. Isolated pelvic perfusion (IPP) by the balloon-occlusion technique provides high-dose regional chemotherapy that may facilitate resection if appropriate or palliate pain and fungating tumor mass in the symptomatic patient. We currently report our results in 49 recurrent rectal cancer patients (26 had neoadjuvant IPP with intent to resect and 23 had IPP for palliation). Methods IPP was done for 1 hour with paclitaxel 30 mg/m², 5 fluorouracil 1500 mg/m², cisplatin/oxaliplatin 60-130 mg/m², and mitomycin C 10 to 15 mg/m² (the latter three achieving pelvic-to-systemic drug ratios of 6–9:1). Results Neoadjuvant perfusion in 26 patients achieved a response in 14 patients (made resectable). Seven had R0 resections (clear margins), six by abdominal sacral resection (ABSR), and one by an extended APR. Of seven other patients, one had a complete pathologic response negating planned resection, one had >50% tumor regression in pelvis (but developed distant metastases), and three refused ABSR. Planned ABSR in two patients was aborted because of complicating cardiovascular issues. A variety of medical and cancer issues precluded resection in the remaining 12 of these 26 neoadjuvant patients. Within the neoadjuvant group, median survival was 24 months in the responding (made resectable) group (14 patients) and it was 8 months in the non-resectable group (12 patients), p = 0.0001. In the responding (made resectable) group, seven patients had R0 resections (median survival 26 months) and seven patients were not resected (median survival 18 months), p = 0.0198. In the IPP group for palliation, 17 of 23 patients (74%) had significant relief of pain, and other tumor-related symptoms (mean survival 11 months). Conclusion Isolated pelvic perfusion using a simplified balloon-occlusion technique has promise in palliation of or augmenting resectability of advanced rectal malignancy in patients not amenable to treatment with conventional modalities.     

Development of an in Situ Isolated Porcine Liver Perfusion Model for Tightly Controlled Physiologic and Pharmacologic Studies

Several types of isolated perfused porcine liver models have been proposed for the study of hepatic assist, preservation injury, and specific physiologic or pharmacologic mechanisms. The development of a more general in situ isolated perfused model applicable to a broad range of studies is presented. This model eliminates or minimizes the shortcomings of previous models including ischemic injury prior to perfusion, limited range of vascular pressures and flows, nonphysiologic sources of portal and hepatic artery perfusion, and coupling of the liver to uncontrolled whole-body homeostatic mechanisms. Essentially the model as presented can be described as an autologous transplanted liver without preservation or ischemic injury, functioning within an adrenalectomized, cardiac output and temperature-controlled animal. Independent control of the dual hepatic vascular supply is maintained with pulsatile perfusion of the hepatic artery from the left atrium and nonpulsatile perfusion of the portal vein via the portal system. Oxygenators are not required. Hepatic vein pressure can be controlled independently of hepatic blood flow and systemic hemodynamics. Pharmacologic studies are not restricted to drugs whose termination of action is limited to hepatic metabolism because normal routes of drug redistribution, metabolism, and excretion are present. The model exhibits normal oxygen metabolism and classic control of hepatic artery resistance by portal vein blood flow. There are rather obvious significant advantages inherent in this model for tightly controlled hepatic physiologic and pharmacologic studies.     

Is the Biological Artificial Liver Clinically Applicable? A Historic Review of Biological Artificial Liver Support Systems

Abstract: Hemoperfusion, hemodiafiltration, plasma exchange, and extracorporeal liver perfusion have already been adopted to treat patients with acute and chronic hepatic failure. However, the survival rate of patients with acute hepatic failure remains at approximately 30% and has not improved as expected. Current advances in biotechnology have opened the way for the development of a biological artificial liver, which is called the hybrid artificial liver because it consists of both biological and artificial materials. Isolated hepatocytes have been investigated for use in various types of hybrid artificial liver. In addition, the role of biomatrices, microcarriers, and the microencapsulation technique has been studied with respect to long-term maintenance of hepatocellular function and development of high-density culture systems for hepatocytes. Before clinical application of hybrid artificial liver support systems becomes possible, many problems have to be resolved, including large-scale preparation and long-term preservation of biomaterials, high-density and stable immobilization of biomaterials on artificial materials, control of immunological hazards, biocompatibility, safe transportation and sterilization of biomaterials, and the high cost. We review the history of biological artificial livers and discuss their future role.     

Portal circulation and the function of hepatocytes during ex vivo perfusion of the rat liver preserved for six hours after core cooling

Portal circulation and the function of hepatocytes during isolated organ perfusion were compared between the rat liver perfused immediately after extirpation and the liver perfused after core cooling and six hours of preservation. Nine rat livers were extirpated after core cooling, preserved for six hours in University of Winsconsin (UW) solution at 4°C and then were connected to a perfusion chamber (hypothermic preservation group: 6-hr HP group). Six rat livers were immediately connected to the perfusion chamber after extirpation (control group). During 60 minutes of isolated liver perfusion, both portal circulation and the function of hepatocytes were determined every 10 minutes. Portal vein resistance increased and portal blood flow decreased during the first 20 minutes of perfusion and then stabilized in both groups. Portal vein resistance was significantly higher and portal blood flow was significantly lower for the first 10 minutes of perfusion in the 6-hr HP group, compared to the control group. The function of hepatocytes, determined by the rate of elimination of ammonia, oxygen consumption, and glucose availability were depressed in the 6-hr HP group, compared to the control groups during isolated liver perfusion. However, there was no statistically significant difference of portal perfusion and the function of hepatocytes between the two groups at the end of perfusion. The results of the present study indicate that the rat liver can be preserved in a satisfactory condition for six hours by the use of hypothermic preservation, coupled with core cooling.     

TNF-Based Isolated Limb Perfusion Followed by Consolidation Biotherapy with Systemic Low-dose Interferon Alpha 2b in Patients with In-transit Melanoma Metastases: A Pilot Trial

BACKGROUND: Tumor necrosis factor (TNF)-based isolated limb perfusion (ILP) yields high tumor response rates in patients with in-transit melanoma metastases. However, most patients will ultimately experience disease recurrence. The aim of this pilot study was to test the hypothesis that systemic low-dose interferon alpha-2b (LDI) might consolidate the therapeutic effect of ILP. METHODS: A total of 12 patients with in-transit melanoma metastases not amenable to surgical excision were given LDI subcutaneously (3 million IU/day, 7 days/week for 12 months) after TNF-based ILP (TNF 1 mg + melphalan (L-PAM) 10 mg/L) (group A). The clinical outcome of these patients was historically compared with that of 19 patients with similar anthropometric and disease characteristics who underwent TNF-based ILP alone (group B). RESULTS: In group A, LDI was well tolerated, only grade 2 systemic toxicity being recorded in 50% of patients. The progression-free survival analysis showed a statistically significant advantage for group A patients as compared with group B (median time to progression: 26 and 17 months, respectively; log-rank test P-value: 0.037). This survival benefit was confirmed at multivariate analysis, where treatment was the only prognostic factor retained by the prediction model. The analysis of the risk of disease progression over time suggested that this survival benefit appears to vanish after LDI discontinuation, which further strengthens the hypothesis that LDI might consolidate the therapeutic effect of TNF-based ILP. CONCLUSIONS: These preliminary findings support the conduction of larger trials to formally assess the ability of LDI to improve the clinical outcome of melanoma patients with in-transit metastases undergoing TNF-based ILP.