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

Regional anticoagulation magnetic artificial blood vessels constructed by heparin-PLCL core-shell nanofibers for rapid deployment of veno-venous bypass

Veno-venous bypass (VVB) is necessary for maintaining hemodynamic and internal environment stabilities in complex liver surgeries. However, the current VVB strategies require systematic anticoagulation and are time-consuming, leading to unexpected complications. This study aims to overcome these limitations by using a novel magnetic artificial blood vessel constructed with heparin-PLCL core-shell nanofibers. Coaxial electrospinning was used to fabricate core-shell nanofibers with heparin encapsulated into the core layer. The microstructure, physical and chemical properties, hemocompatibility, and heparin release behavior were characterized. The regional anticoagulation magnetic artificial vessel was constructed with these nanofibers and used to perform VVB in a rat liver transplantation model for in vivo evaluation. The core-shell nanofibers appeared smooth and uniform without apparent defects. Fluorescence and TEM images indicated that heparin was successfully encapsulated into the core layer. In addition, the in vitro heparin release test presented a two-phase release profile, burst release at day 1 and sustained release from days 2 to 14, which resulted in better hemocompatibility. The VVB could be rapidly deployed in 3.65 ± 0.83 min by the magnetic artificial vessel without systemic anticoagulation. Moreover, the novel device could reduce portal pressure and abdominal organ congestion, protect intestinal function, and increase the survival rate of liver transplantation with a long anhepatic phase from 0 to 65%. In summary, VVB can be rapidly deployed using regional anticoagulation magnetic artificial blood vessels without systemic anticoagulation, which is promising for improving patient outcomes after complex liver surgery.

Toward failure analyses in systems biology

Parallels between designed and biological systems with respect to formal failure analyses have been presented. Failure analysis in designed systems depends on an identified, limited set of parameters or operation variables with high predictive value. In contrast, the biological systems pose problems in identification of operation variables and the identified variables may not be accurate predictors of failure. The difficulty in parameter identification is because of large numbers of components and the inability to envelope variables at each compartment or contour level. Contour level maps for biological systems are currently non-existent, and most failure models are based on very limited, unilateral operation variables (a mutant gene). Operation variable identification within each contour level will enhance failure analyses of complex biological systems.

Modified infusion procedures affect recombinant adeno-associated virus vector type 2 transduction in the liver

Recombinant adeno-associated virus (rAAV) vectors have therapeutic potential for the treatment of several types of liver diseases including hepato-deficiency disorders. Most of the preclinical and clinical applications involve the use of adeno-associated vector serotype 2 (AAV-2). However, when this vector is delivered at high doses into the portal vein or hepatic artery, a relatively small number of hepatocytes are stably transduced. We elected to determine if the route of vector administration and altering the vascular delivery route within the liver influenced the relative level of transduction. First, we delivered an AAV vector expressing the human factor IX gene from a liver-specific promoter into the hepatic artery, portal vein, or general circulation of rats. Transgene expression was equal with hepatic artery and portal vein infusion, which was higher than vector administered via peripheral venous infusion. Next, we determined how localized perfusion or changing the vector dwell time affected AAV transduction in vivo. To do this, we infused an AAV vector lacking a functional expression and quantified transduction by quantifying the number of double-stranded vector DNA genomes. By increasing vector dwell time in the liver to 5 min, vector transduction was enhanced approximately 4- to 5- fold. To establish if gene transduction could be restricted to a specific anatomic location in the liver, we delivered vector into specific liver lobes by clamping the venous inflow to the middle and left liver lobes (noninfused lobes) and infusing vector into the right two liver lobes through the hepatic artery followed by vector circulation between the two right lobes and general circulation for 5 min. With this selective infusion, 40 to 120 times higher vector genome was observed in the perfused lobes than the nonperfused lobes. All the procedures described in this study were performed without detectable liver injury or toxicity. In all, the present study clearly demonstrated that hepatic arterial infusion of rAAV is effective for liver-directed gene therapy and that other parameters related to blood flow can be adjusted to further optimize gene transfer.

The Past Decade of Experience With Isolated Hepatic Perfusion

Metastatic or primary unresectable cancers confined to the liver are the sole or life-limiting component of disease for many patients with colorectal cancer, ocular melanoma, neuroendocrine tumors, or primary colangio- or hepatocellular carcinomas. Regional treatment strategies including infusional chemotherapy and local ablative therapy are under investigation, but have limitations with respect to the clinical conditions under which they can be employed. Isolated hepatic perfusion (IHP) was first clinically applied over 40 years ago, but because of its technical complexity, the attendant potential morbidity, and the lack of documented efficacy, it has not enjoyed consistent or widespread evaluation. In light of the antitumor activity with isolated limb perfusion with tumor necrosis factor (TNF) and melphalan in patients with unresectable extremity sarcoma or in transit melanoma, this regimen has been administered via IHP at several centers worldwide for patients with unresectable liver cancers. IHP with TNF and melphalan can result in significant regression of advanced refractory cancers from multiple histologies confined to the liver. Patient selection is important to ensure good results with minimal morbidity and mortality. Work to define the appropriate clinical groups is ongoing at many clinical centers.

Isolated liver perfusion for non-resectable liver tumours: a review

Many treatments have been proposed for non-resectable primary or secondary hepatic cancer but the results have generally been disappointing. Isolated Hepatic Perfusion (IHP) was first attempted four decades ago but it gained acceptance only recently, after spectacular tumour responses were obtained by isolated limb perfusion with melphalan and tumour necrosis factor (TNF) for melanomas and sarcomas. Surgical isolation of the liver is a technically demanding operation that allows the safe administration of high doses of chemotherapeutics and TNF. Percutaneous techniques using balloon occlusion catheters are simpler but result in higher leakage rates from the perfusion circuit into the systemic circulation. Several phase I-II trials indicate that IHP can yield high tumour response rates, even when there is resistance to systemic chemotherapy. However, no significant advantage in overall survival has been demonstrated so far. IHP offers unique pharmacokinetic advantages for locoregional chemotherapy and biotherapy. It might also allow gene therapy with limited systemic exposure and toxicity. At present, IHP nevertheless remains an experimental treatment modality which should therefore be used in controlled trials only.

Stop-flow technique for loco-regional delivery of antiblastic agents: literature review and personal experience

AIMS

The therapeutic approach for primary or recurrent advanced solid tumours, particularly when unresectable, is still one of the main medical challenges in the management of cancer patients. The stop-flow (SF) technique has been recently proposed as a semi-invasive drug delivery system based on the blood supply blockage of the tumour-bearing area. Here, we discuss the principles underlying the SF technique as well as the worldwide experience published so far. We also report on the results of our pilot study on pelvic and limb SF perfusion.

METHODS

We reviewed the worldwide experience on SF as reported by the literature published on PubMed from 1990 through 2001. In our series, we treated 20 patients affected with locally advanced melanoma, soft tissue sarcoma or colorectal cancer.

RESULTS

This therapeutic modality - at least for some tumours - can achieve encouraging results in terms of clinical response even after conventional therapies have failed. Moreover, as a safe and relatively simple procedure, SF can be applied to patients for whom traditional treatments (i.e. surgery, systemic chemotherapy) are contraindicated because of poor general conditions.

CONCLUSIONS

At present, the SF technique should be considered an investigational approach to locally advanced cancers. The encouraging results obtained with this procedure should be validated by large phase III trials.

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.

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 degrees 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+/-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.

The surgical technique of isolated hyperthermic arterial liver perfusion in humans

Various techniques of isolated liver perfusions have been described, using hepatic artery or both hepatic artery and portal vein. In this paper the technique of isolated arterial liver perfusion is presented. Twelve patients suffering from non-resectable liver tumors underwent this approach. All of them had been previously unsuccessfully treated by resection or systemic chemotherapy. The liver perfusions were performed without technical problems. No operative death occurred. The mean operating time was 413 +/- 29 min. Although the perfusion medium was oxygenated and the absolute anoxic period was shorter than 10 min in all cases the perfused livers showed a marked postoperative increase of liver enzyme levels. Further studies should be aimed at reducing this hepatic injury and simplifying the complex surgical procedure.

Asanguineous isolated hyperthermic perfusion of the liver: results of an experimental study in pigs

Asanguineous hyperthermic liver perfusion was performed in five and seven pigs for 30 and 45 min respectively. Laboratory data, including changes of liver enzyme levels and results of liver function tests, as well as morphological alterations of liver structure, were compared with data from a 45-min oxygenated hyperthermic liver perfusion. In the group undergoing asanguineous liver perfusion survival was four of five and five of seven animals. In the oxygenated group six of seven pigs survived. Liver enzymes and function tests in the two groups with a 45-min perfusion time were not significantly different. All enzyme and laboratory test values returned to normal within 1 week. Similarly morphological changes were reversible within 1 week. The results suggest that asanguineous isolated hyperthermic liver perfusion up to 45 min is feasible without damage to liver tissue.

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.

Hyperthermo-chemo-hypoxic isolated liver perfusion for hepatic metastases: a possible adjuvant approach

As a possible intraoperative adjuvant approach to treating hepatic metastases we developed a method of hyperthermo-chemo-hypoxic isolated liver perfusion in combination with hepatic resection. This method was applied to 11 patients with colorectal hepatic metastases between 1992 and 1995. One patient died on postoperative day 14 of hepatic failure (9% mortality), the cause of which was live temperature that reached 42.9 degree C, which seems to be the maximum limit for thermal toxic effect on the human liver. The other 10 patients tolerated the perfusion well, with mild hepatic and non systemic toxicity after minor or even major hepatic resection; the serum aminotransferase and total bilirubin levels returned to normal levels by postoperative day 14. Only one of eight patients (13%) for whom cytotoxic drugs were added to the perfusate (mitomycin C 10 micrograms/ml or cisplatin 2 micrograms/ml) had hepatic recurrence by 19 months after the perfusion (mean follow-up 25.8 months; median 23 months; range 8-57 months). Two patients were alive with no evidence of disease at 13 and 57 months, respectively after the perfusion; the other five patients had postperfusion extrahepatic recurrences (median: 19 months; range 7-20 months). In contrast, hepatic metastases recurred 7 and 20 months after the perfusion, respectively, in the two patients not given a cytotoxic drug.

Management strategies for colorectal liver metastases--Part II

Liver metastases are relatively common in colorectal cancer and a small proportion of patients may benefit from resection of these liver metastases. In a selected subgroup of patients, 5-year survival rates of 25-35% may be achieved following liver resection. These survival figures compare favourably with those of patients with untreated liver secondaries. In the second part of this review the surgical and non-surgical treatment options for treating colorectal liver metastases are examined in detail.