Hepatic hyperthermia by total isolation and regional perfusion in vivo

The serum interleukin 8 level reflects hepatic mitochondrial redox state in hyperthermochemohypoxic isolated liver perfusion with use of a venovenous bypass

BACKGROUND

We have recently developed a simple method of hyperthermochemohypoxic isolated liver perfusion (HILP) as a regional therapy for unrecognized liver micrometastases. However, little is known about the influence of HILP on cytokine production and liver function. We investigated the influence of HILP on interleukin 8 (IL-8) production and the hepatic mitochondrial function and assessed the relationship between these 2 parameters. We also measured the serum tumor necrosis factor-alpha (TNF-alpha) and interleukin 1 beta (IL-1 beta) levels to examine the involvement of HILP-induced cytokines in the tumor response.

METHODS

Sixteen patients with metastatic liver tumors were randomly assigned to undergo hepatectomy with HILP (group A, n = 9) or hepatectomy alone (group B, n = 7). The isolated liver was perfused for 30 minutes with Ringer's lactate solution containing chemotherapeutic agents warmed to 42 degrees C to 43 degrees C without oxygenation.

RESULTS

The serum IL-8 levels in group A were markedly increased, with peaks at 3 hours after reperfusion, which was significantly higher than levels in group B (P < .01). In group A the arterial ketone body ratio, which reflects the hepatic mitochondrial redox state, decreased during perfusion and was gradually restored to the preperfusion level 1 hour after reperfusion. However, in group B it decreased during hepatectomy but rapidly recovered 5 minutes after hepatectomy. There was a significant negative correlation between the peak serum IL-8 level and the initial velocity of arterial ketone body ratio recovery for the first 5 minutes after reperfusion r = -0.83, P < .001). The serum TNF-alpha and IL-1 beta were temporarily detected only in 3 of 9 patients in group A.

CONCLUSIONS

We have shown that HILP resulted in augmented IL-8 release but not TNF-alpha and IL-1 beta and that the serum IL-8 level reflects the hepatic mitochondrial redox state. These findings suggest that IL-8 production may be associated with hepatic mitochondrial impairment during ischemia. This work may contribute to new therapeutic strategies not only for hepatic ischemia reperfusion injury but also for metastatic liver tumors.

A porcine model for investigation of hyperthermic isolated liver perfusion

Our study was aimed at developing a reliable method of hyperthermic isolated liver perfusion (HILP) in pigs and at assessing its local and systemic side effects. HILP was performed via the hepatic artery and portal vein in 15 animals. The perfusate consisted of blood (200 ml), oxypolygelatine (500 ml), Ringer's solution (1000 ml), and trapped intrahepatic blood. HILP was carried out for 45 min at a mean perfusate inflow temperature of 41.2 degrees C. The mean portal flow and pressure were adjusted to 500 ml/min and 20-25 mm Hg; the mean arterial flow and pressure were 130 ml/min and 40-60 mm Hg, respectively. After 20 min of perfusion the mean temperature in the right and the left liver lobe were 40.8 degrees C and 40.3 degrees C and remained almost constant over the whole perfusion period. Liver enzymes (alanine aminotransferase and aspartate aminotransferase) and serum lactate levels showed slight increases after perfusion but normalized within 1 week. Histology of liver parenchyma showed only mild pathological changes, which were also reversible within 7 days. The presented method of HILP is a safe and reproducible technique for isolated hyperthermic liver perfusion. Based on this animal model, experimental HILP with different chemotherapeutic agents can be investigated in order to assess hepatic and systemic toxicity of this therapy.

First experience and technical aspects of isolated liver perfusion for extensive liver metastasis

BACKGROUND

New drugs and modalities for locoregional tumor treatment in recent years may offer new potential for isolated liver perfusion in patients with nonresectable liver tumors. The purpose of this study was to prove the feasibility of arterial isolated liver perfusion and to assess the tolerance of perfusion with high-dose tumor necrosis factor (TNF).

METHODS

Twelve patients with extensive liver metastases previously treated unsuccessfully with systemic chemotherapy underwent isolated hyperthermic liver perfusion using a heart-lung machine. High doses of mitomycin were administered in the first six and a combination of TNF and melphalan in the last six patients.

RESULTS

No operative death occurred and no direct postoperative liver failure was observed in any patient. In cases of variations of the arterial hepatic blood supply, the perfusion was done through the splenic artery or an angiography catheter. Histologic analysis of tumor biopsy specimens obtained on the first postoperative day revealed major tumor necrosis in 8 of 12 patients.

CONCLUSIONS

Isolated arterial perfusion of the liver is a complex surgical procedure that is feasible in patients with anatomic variations of the hepatic artery. The remarkable histologic response to perfusion in several pretreated patients, especially after application of high-dose TNF and melphalan, suggests that this modality is very effective in tumor killing.

Isolated hepatic perfusion in the pig with TNF-alpha with and without melphalan

Isolated limb perfusion with tumour necrosis factor alpha (TNF-alpha) and melphalan is well tolerated and highly effective in irresectable sarcoma and melanoma. No data are available on isolated hepatic perfusion (IHP) with these drugs for irresectable hepatic malignancies. This study was undertaken to assess the feasibility of such an approach by analysing hepatic and systemic toxicity of IHP with TNF-alpha with and without melphalan in pigs. Ten healthy pigs underwent IHP. After vascular isolation of the liver, inflow catheters were placed in the hepatic artery and portal vein, and an outflow catheter was placed in the inferior vena cava (IVC). An extracorporeal veno-venous bypass was used to shunt blood from the lower body and intestines to the heart. The liver was perfused for 60 min with (1) 50 microg kg(-1) TNF-alpha (n = 5), (2) 50 microg kg(-1) TNF-alpha plus 1 mg kg(-1) melphalan (n = 3) or (3) no drugs (n = 2). The liver was washed with macrodex before restoring vascular continuity. All but one pigs tolerated the procedure well. Stable perfusion was achieved in all animals with median perfusate TNF-alpha levels of 5.1 +/- 0.78 x 10(6) pg ml(-1) (+/- s.e.m). Systemic leakage of TNF-alpha from the perfusate was consistently < 0.02%. Following IHP, a transient elevation of systemic TNF-alpha levels was observed in groups 1 and 2 with a median peak level of 23 +/- 3 x 10(3) pg ml(-1) at 10 min after washout, which normalized within 6 h. No significant systemic toxicity was observed. Mild transient hepatotoxicity was seen to a similar extent in all animals, including controls. IHP with TNF-alpha with(out) melphalan in pigs is technically feasible, results in minimal systemic drug exposure and causes minor transient disturbances of liver biochemistry and histology.

Development of an isolated perfusion circuit with double bypass using automatic blood pumps

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 oxygenator 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.

Simple method of hyperthermo-chemo-hypoxic isolated liver perfusion for hepatic metastases

As a regional therapy for hepatic malignancy, we developed a simple method of isolated liver perfusion (hyperthermo-chemo-hypoxic). In the present study, the influence of this method on the hepatic tissue and other organs was experimentally evaluated and applied it to seven patients. Experimentally, all dogs survived without hepatic insufficiency and systemic toxicity. Clinically, one patient died on postoperative day 14 of hepatic failure. The reason was that liver temperature reached 43 degrees C, which seemed to be the maximum limit for thermal toxic effect to the human liver. The other six patients well tolerated the perfusion with mild increases of serum aminotransferase and total bilirubin levels and decreases of hepaprastin levels. Serum aminotransferase and total bilirubin and hepaprastin levels returned to normal levels by postoperative day 14. There were no significant differences between the isolated liver perfusion group (n = 7) and hepatectomy-only group (n = 27). Six patients were disease-free during the observation period after the perfusion. This system is a simple, useful method for treating patients with metastatic cancer limited to the liver.

A model for directed foreign gene delivery to rat liver cells in vivo

A novel technique for directed delivery of retroviral genes to rat liver cells in vivo is described. Vascular isolation of the liver was achieved in situ and perfusate containing retrovirus expressing the bacterial gene conferring resistance to Hygromycin-B was delivered selectively to the posterior liver lobes. After 15 min, normal blood flow to the liver was restored. The portal venous branch supplying the two anterior liver lobes was ligated either at the same time (Group I, n = 4) or 20 hr prior to perfusion (Group II, n = 4) to stimulate DNA synthesis in the posterior lobes. Controls (Group III, n = 4) were perfused with retrovirus without portal branch ligation. Hepatocyte transduction was assessed 7 days later by isolating the cells and assessing their viability in a selection medium. In Group I and II rats, 9.2 +/- 0.5 and 16.0 +/- 1.0%, respectively, of harvested hepatocytes, expressed the Hygromycin-B gene. In contrast, a significantly smaller number of hepatocytes (2.8 +/- 0.9%, P less than 0.003) expressed the gene in the absence of stimulation of DNA synthesis.

A technique for isolated liver perfusion in the rat with survival and results of cytotoxic drug perfusion on liver tumor growth

The toxic side effects of many chemotherapeutic agents prevent their use in high concentrations. Isolated perfusion techniques have been used most commonly for malignancies involving the extremities, but recently also for irresectable liver tumors. This paper describes a technique for in vivo isolated liver perfusion for 30 min with oxygenated blood through the portal vein and hepatic artery simultaneously. There was a 14% mortality rate. There was some initial hepatocellular death, which resolved quickly and did not seriously affect liver function. There was only a small leak from the perfusion system to the systemic circulation. We tested the system on an experimental liver tumor from a colonic adenocarcinoma. Perfusion with added 5-FU in a toxic dose of 70 mg/kg to the medium significantly retarded tumor growth evaluated 10 days after perfusion compared to rats perfused without 5-FU. This model closely resembles the technique applied clinically and will enable further work on effects of perfusion in an experimental rat liver tumor model.

Extracorporeal hemofiltration: a model for decreasing systemic drug exposure with intra-arterial chemotherapy

Cisplatin (3 mg/kg) was infused through the hepatic artery in nine mongrel dogs. Four of these dogs underwent simultaneous extracorporeal hemofiltration (ECH) of the hepatic venous effluent using a high-flow, dual-lumen catheter placed in the vena cava at the level of the hepatic veins. Platinum levels were measured in the plasma, urine, and ultrafiltrate and in kidney and liver tissue. ECH significantly reduced systemic drug exposure as measured by the AUC for free and total platinum, by urinary excretion, and by 24-h kidney levels. Regional liver levels were minimally affected. Recovery of platinum in the ultrafiltrate was 40% +/- 14%. ECH resulted in efficient extraction of platinum and reduced systemic drug exposure with relative preservation of regional hepatic drug exposure.

Hyperthermic liver toxicity: a role for oxidative stress

Rat livers were perfused at 37 degrees C, 41 degrees C, 42 degrees C, 42.5 degrees C, and 43 degrees C for 2 hr. Among perfusate constituents analyzed were urea, total amino acids, N-acetyl-beta-glucosaminidase (NAG), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), malonaldehyde (MDA), glutathione (GSH), oxidized glutathione (GSSG), allantoin, potassium, phosphate, and glucose. After perfusion, livers were homogenized and analyzed for xanthine oxidase (XO) activity, GSH content, and lysosomal lability. Perfusate AST, LDH, NAG, potassium, glucose, and phosphate increased significantly with time, and there were significant differences in the final values between 37 degrees C and 42 degrees C, 42.5 degrees C and 43 degrees C (P less than .05). GSH levels increased significantly at all temperatures after 90 and 120 min, whereas GSSG levels differed significantly at 60, 90, and 120 min for 37 degrees C vs. 42 degrees C, 42.5 degrees C, and 43 degrees C (P less than .05). Mean MDA levels at 37 degrees C differed from those at 41 degrees C and 43 degrees C (P less than .05) at each temperature. Allantoin levels increased significantly with time of perfusion; mean levels at 37 degrees C were significantly different from mean levels at each temperature at 60, 90, and 120 min. GSH liver tissue levels decreased with perfusion at hyperthermic temperatures; mean values at 41 degrees C, 42 degrees C, and 42.5 degrees C, and 43 degrees C differed from 37 degrees C mean values (P less than .01). Type O XO increased after 120 min perfusion from 6.4% +/- 2.0% at 37 degrees C to 55% +/- 30%, 43% +/- 27%, and 63% +/- 29% at 42 degrees C, 42.5 degrees C, and 43 degrees C, respectively. Lysosomal lability increased after perfusion at 42.5 degrees C. There was a significant increase in nonsedimentable NAG activity at 42.5 degrees C (P less than .05). These data support the premise that hyperthermic toxicity to the liver may be a consequence of oxidative stress brought about by enhanced adenosine triphosphate (ATP) consumption and conversion of XO to type O. Such conversion results in superoxide formation and subsequent depletion of cellular GSH, labilization of the lysosomes, and plasma membrane damage.

Focal intestinal heating with regional abdominal hyperthermia

The effect of regional abdominal heating on the small and large bowel was evaluated in three female research pigs. The BSD Annular Phased Array was used for heating. Blind-end catheters and a free peritoneal probe were surgically attached to small bowel, large bowel, liver, and kidney. Each pig underwent 4-8 heating sessions and was subsequently autopsied. There was no histologic evidence of acute bowel, liver, or kidney damage. There were significant differences in temperatures at the various sites. The average small bowel temperature was significantly higher than predicated by the free peritoneal probe or than seen in the liver or kidney. The large bowel temperatures averaged higher than the free peritoneal probe temperatures, but the difference was not significant. Liver and kidney temperatures approximate whole body temperature due to extensive vascular network. Although the elevated small bowel temperatures may be due in part to different position in relation to isotherms, the frequent occurrence of a large temperature difference suggests focal heating of fluid pockets in the small bowel.

A successful technique of in vivo isolated liver perfusion in pigs

A technique was developed to isolate the hepatic circulation from the general circulation using a double lumen intracaval shunt. Low flow normothermic perfusion of the liver was performed for 1 hr 25 min in pigs. All pigs survived the procedure. The isolated liver perfusion without chemotherapy (n = 11) was well tolerated as monitored by hepatic enzymes and histologic examination during and after the operation. Mild transient elevations of SGOT and LDH returned to normal values within 1 week. No significant pathological alterations were found in the liver biopsies. Twenty-two pigs were subjected to isolated liver perfusion with 20, 40, or 80 mg 5-FU/kg. Up to four times the conventional dose of the drug could safely be administered when a washout was performed. To evaluate the efficacy of the isolation a method for leakage detection was developed, using tracer quantities of 99mTc-labeled red blood cells. This method was sensitive and permitted continuous monitoring of leakage. Negligible leakage was found during 15 isolated liver perfusions. The described technique of isolated liver perfusion was a reliable and technically feasible method, and has been adapted for clinical use to evaluate its value in the treatment of hepatic metastases.

Isolation-perfusion of the liver with 5-fluorouracil

Isolation-perfusion of the liver was performed in ten pigs using 5-fluorouracil administered in the perfusion circuit at doses of 100, 250, 500, and 1000 mg/kg body weight. Perfusion was performed for 60 minutes at normothermic (37 C) or hyperthermic (41 C) temperatures. One animal died shortly after perfusion. Incomplete isolation of the hepatic vasculature in two animals resulted in significant drug leakage into the systemic circulation with resulting hematologic toxicity. Perfusion with 5-fluorouracil at 1000 mg/kg produced hepatic necrosis. Perfusion with 5-fluorouracil at doses of 100, 250, or 500 mg/kg produced no hepatic toxicity except for transient elevations of hepatic enzymes and resulted in no systemic drug toxicity. Levels of 5-fluorouracil tolerated by the liver in the isolation-perfusion system were more than 1000-fold greater than the maximum drug levels achievable by routine systemic, intra-arterial, or intraperitoneal administration.

A technique for isolated hyperthermic liver perfusion

Hyperthermia, either alone or combined with chemotherapy, has been shown to be effective in treating cancer. Because some investigators believe that regional hyperthermia may be more effective than whole body hyperthermia, we developed a technique to heat only the liver to 42-43 degrees for 4 hr. The procedure was adapted from a previously described animal model and was performed in four humans. Vascular isolation of the liver was accomplished by cannulating the hepatic artery, the portal vein, and the inferior vena cava followed by occluding the suprahepatic vena cava and the liver was then perfused with blood and nutrients from an oxygenated reservoir. Preliminary results show radiologic and histologic evidence of tumor necrosis or cessation of tumor growth in three of the patients. We believe this technique is safe enough for clinical experimental use and deserves further investigation.

Hyperthermochemotherapeutic in vivo isolated perfusion of the rat liver

This report describes a system of in vivo isolated perfusion of the rat liver. The effects of perfusion with 5-fluorouracil (5-FU) (0.125-1.5 g/kg) on survival, liver function, and hepatic regeneration are studied. A dose of 0.125-0.25 g/kg of 5-FU produced acceptable toxicity with 0% and 25% mortality rate, but induced liver dysfunction indicated by abnormal biochemical values and severe inhibition of hepatic regeneration. Doses of 0.5 g/kg, 1.0 g/kg, and 1.5 g/kg produced a mortality of 60%, 100%, and 100%, respectively. Regional hyperthermia (37-43 degrees C) achieved by perfusion of the liver with heated saline produced an adverse effect on survival, liver function and hepatic regeneration, which are both temperature- and perfusion time-dependent. Hyperthermochemotherapy using in vivo isolated hepatic perfusion might be acceptable for the treatment of unresectable liver cancer, but should not be utilized as an adjuvant therapy prior to hepatic resection without the use of hepatic growth factors which could reverse the inhibitory effect of hepatic perfusion.

A technique for isolation perfusion of the canine liver with survival

A technique of isolation perfusion of the canine liver was developed as a model for treating cancer limited to the liver. Preservation of hepatic functional integrity was dependent on maintenance of near physiologic conditions for the perfusion. Flow to the liver, 1 ml/min/g, was provided by gravity to the portal vein at two thirds total flow, and by pump to the hepatic artery at one third total flow. Utilizing the technique described, six dogs died 4-12 hr after a 1-hr perfusion. The dogs received Ringer's lactate solution IV and had a rising blood lactate to greater than 9 mM and a rising lactate/pyruvate ratio. After changing IV fluids to nonlactate containing solutions, 4/6 dogs survived a 1-hr perfusion at 37 degrees. Blood lactate concentrations remained below 6 mM (alpha less than 0.05) during perfusion, and the lactate/pyruvate ratios remained in a physiologic range on comparison to the nonsurvivors (alpha less than 0.05). Mild elevations occurred in the SGOT and SGPT with the peak on the first postoperative day of 93 +/- 54 and 79 +/- 56, respectively, but returned to normal within 4-7 days. Perfusate chemistries lactate, pyruvate, glucose, total alpha-amino acids, ketone bodies, SGOT, and SGPT demonstrated that hepatic functional integrity was maintained during the 1-hr perfusion. Hepatic function as assessed was no different between survivors and nonsurvivors. Hypoglycemia (glucose less than 2 mM) contributed to the two deaths. Tolerance of the dog to the temporary anhepatic state may be the limiting factor to prolonged perfusions.

Intra-arterial chemotherapy of the liver with transient, repeated hypoxia

Intra-arterial liver perfusion with transient repeated hypoxia via an indwelling double-lumen polyurethane catheter was undertaken in 25 of 33 patients with diffuse metastases involving 50%-70% of the liver, and whose primary cancer had previously been treated by local radical resections. Treatment continued over 3-12 months until disease progression and over 3-24 months until thrombosis. In 24 patients with colorectal carcinoma the 1-year survival rate (using the actuarial method) was 79% +/- 17%. The treatment morbidity was low. It is concluded that this form of treatment improves the quality of life and gives safe and effective palliation to the patients.

[A new method for isolated regional perfusion of the liver in vivo. Experimental studies (author's transl)]

The canine liver was isolated from its blood supply and perfused for one hour normothermically be means of a new catheter and a perfusion system consisting of oxygenator, pump and heat-exchanger. Hemodynamic parameters, blood gas analyses, and tissue metabolites were evaluated during experiments. The venous return from the lower body and portal vein (1.113/1min) could be maintained with the catheter system so that the mean systemic arterial pressure was within normal limits. With a perfusion rate through the liver 0,55 ml/min/g and perfusion pressure of 10 cm H2O there was an adequate tissue perfusion; this was also shown by blood gas analyses and tissue metabolite concentrations. Using dye dilution methods the isolation of the liver was tested. This showed a leakage of 6-7% of the total perfusion volume. This new method makes it possible to carry out an isolated, normothermic, liver perfusion for one hour without irreversible tissue damage.

Effects of systemic hyperthermia and intrahepatic infusion with 5-fluorouracil

Potential hepatotoxicity from systemic hyperthermia (43 degrees C) +/- simultaneous hepatic artery infusion with 5-FU was evaluated in an animal model. Twenty-two dogs had aorta-vena caval shunts (8 mm Dacron grafts) placed, and 10 of these dogs had silastic catheters inserted in their hepatic arteries. Two weeks later, Group I (n = 8) was heated to 43 degrees C for one hour (distal esophageal + intrahepatic temperature) using the shunts and blood-heat exchangers; Group II (n = 6) was heated to 43 degrees C for one hour with simultaneous intrahepatic infusion of 5-FU (10 mg/kg); Group III (n = 8) was shamheated (37 degrees C) and underwent a one hour intrahepatic infusion with 5-FU (10 mg/kg). Serum alkaline phosphatase, SGOT, SPGT (IU/ml) and bilirubin were measured, and liver biopsies were obtained at 0 and 1 hour, at one and seven days. Mean SGOT levels increased significantly (P less than 0.05) in Group II from 19 +/- 2 to 31 +/- 6 and 63 +/- 18 at one hour and one day; these levels rose slightly in Group I from 31 +/- 5 to 40 +/- 8 and 47 +/- 8 at one hour and one day. Hepatocellular enzyme levels returned to normal at seven days in both groups. Mean SGOT and SGPT levels remained similar in Group III at all time periods. No significant differences in mean serum alkaline phosphatase or bilirubin levels were noted. There was no histologic evidence of hepatocellular necrosis at any time period. Survival was 6/8, 5/6 and 8/8 dogs in Groups I, II, and III, respectively. Systemic hyperthermia to 43 degrees C for one hour in dogs does not adversely affect serum hepatic enzymes or cell structure; reversible serum hepatic enzyme changes occurred when hyperthermia was combined with hepatic artery infusion with 5-FU.