A human melanoma xenograft in a nude rat responds to isolated limb perfusion with TNF plus melphalan

BACKGROUND: Isolated limb perfusion (ILP) with tumor necrosis factor-alpha (TNF) and melphalan for advanced extremity malignancies achieves significant complete response rates. To study molecular mechanisms underlying this response, a nude rat ILP model with a human melanoma xenograft was developed. METHODS: NIH1286 human melanoma was grown subcutaneously in the hind limb of nude rats. Anesthetized rats underwent a 10-minute ILP via femoral vessels with hetastarch, heparin, and melphalan, TNF, or TNF plus melphalan. The tumors and ulcers were measured and viable tumor area was calculated. Post-ILP tumors were analyzed by electron microscopy for vascular damage and also by liquid chromatography atmospheric pressure chemical ionization tandem mass spectrometry (LC/APCI/MS/MS) for free melphalan levels. Colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-dephenyltetrazolium bromide (MTT) assays were performed on NIH1286 cells and human dermal microvascular endothelial cells (HDMVEC) to test for direct cytotoxicity to TNF and melphalan. Post-ILP tumors sections were also examined by electron microscopy. RESULTS: The mean maximal decrease in viable tumor area after ILP for control, TNF, melphalan, and TNF + melphalan groups were 0%, 22 +/- 13%, 61 +/- 14%, and 100 +/- 0%, respectively. LC/APCI/MS/MS revealed no difference in the free tumor melphalan concentration between melphalan alone and TNF + melphalan groups. The percent cytotoxicity in MTT assays using TNF, melphalan, and TNF + melphalan against NIH1286 were 0%, 51-59%, and 74-81%, respectively, and against HDMVEC were 28%, 16-23%, and 6-13%, respectively. Electron microscopic analyses showed that addition of TNF to the perfusate caused erythrostasis in tumor blood vessels. CONCLUSION: We developed a human melanoma nude rat ILP model with tumor responses very similar to the human ILP trials. This model will allow further investigation of the synergistic mechanism of TNF and melphalan in human melanoma in a preclinical setting, and extension of this study to current clinical trials.     

In-transit melanoma: the role of alkylating-agent resistance in regional therapy

BACKGROUND: Regional perfusion treatments for melanoma, using the alkylating agent melphalan, show variable responses in magnitude and duration. Surprisingly, the potential contribution of alkylating-agent resistance mechanisms to diminish tumor responses, especially the crucial cellular detoxifying system formed by glutathione (GSH) and its associated enzyme glutathione-S-transferase (GST), has remained unexplored. Objectives of this study were to characterize GSH levels and GST activity in melanoma of patients undergoing regional perfusion and examine the effect of melphalan concentration in both an in vitro human melanoma cell line and in the extremity melanoma of an in vivo rodent limb infusion model. STUDY DESIGN: Human in-transit melanoma, muscle, subcutaneous tissue, and skin (n = 9) and metastatic regional lymph nodes (n = 7) were evaluated for GSH level and GST activity. Effects of increasing melphalan exposure on GSH and GST were studied in an in vitro human melanoma cell line. A survival human melanoma xenograft model of isolated limb infusion using increasing dosages of melphalan was used, with evaluation of GSH and GST in the recurrent tumor. RESULTS: GSH levels in human in-transit lesions and muscle were significantly higher than that of skin and subcutaneous tissue. Four of 9 patients had tumor-to-muscle GSH ratio > 1. A strong correlation was seen between in vitro melphalan dose and resultant GSH level and GST activity. In vivo recurrent tumor GSH levels correlated with increasing melphalan infusion dose. CONCLUSIONS: A GSH-based resistance pathway may play a role in effecting response and toxicity to regional melphalan perfusion.     

Acute stress and intravesical corticotropin-releasing hormone induces mast cell dependent vascular endothelial growth factor release from mouse bladder explants

PURPOSE: Corticotropin-releasing hormone is typically released from the hypothalamus but it has proinflammatory effects outside of the brain, possibly through the activation of mast cells. These cells express corticotropin-releasing hormone receptors with selective secretion of vascular endothelial growth factor, which may be involved in the pathogenesis of painful bladder syndrome/interstitial cystitis. This condition is characterized by bladder inflammation and worsened by stress. We investigated the effect of intravesical corticotropin-releasing hormone and acute restraint stress on vascular endothelial growth factor release from mouse bladder explants and the role of mast cells. MATERIALS AND METHODS: The bladder of C57BL/6 mast cell deficient (W/W(v)) and normal congenic (+/+) female mice (Jackson Laboratories, Bar Harbor, Maine) at ages 10 to 12 weeks was catheterized using anesthesia. After emptying urine 1) normal saline or corticotropin-releasing hormone was introduced for 45 minutes, urine was collected and the mice were allowed to recover for 4 hours before sacrifice or 2) the mice were stressed by placing them in a restrainer for 4 hours before sacrifice and urine was collected 2 hours after stress. The bladder was removed 4 hours after stress and processed for corticotropin-releasing hormone immunohistochemical staining. In other experiments the bladder was removed, minced into 1 mm(2) pieces and cultured with or without corticotropin-releasing hormone overnight. Urine and medium were frozen for histamine, interleukin-6, tumor necrosis factor-alpha and vascular endothelial growth factor assay. RESULTS: Corticotropin-releasing hormone (100 nM) or acute restraint stress (4 hours) increased histamine release in urine and vascular endothelial growth factor release in medium without increasing interleukin-6 or tumor necrosis factor-alpha in the bladder explants of C57BL/6 or +/+ but not W/W(v) mice. No vascular endothelial growth factor, interleukin-6 or tumor necrosis factor-alpha was detected in urine before or after stimulation. Corticotropin-releasing hormone immunoreactivity was present in control bladders but it increased dramatically in the bladder of stressed mice. CONCLUSIONS: Intravesical corticotropin-releasing hormone and acute restraint stress induced mast cell dependent vascular endothelial growth factor release from bladder explants. These findings suggest that stress, corticotropin-releasing hormone, mast cells and vascular endothelial growth factor might participate in the pathogenesis of painful bladder syndrome/interstitial cystitis, which is worsened by stress, and provide for new therapeutic targets.     

Alpha-galactosyl-mediated activation of porcine endothelial cells: studies on CD31 and VE-cadherin in adhesion and signaling.

BACKGROUND: Ligation of alpha-galactosyl epitopes on endothelial cells by naturally occurring human antibodies causes hyperacute rejection in porcine-to-human xenotransplantation. The alpha-galactosyl-specific lectin Bandeiraea simplicifolia isolectin B4 (IB4) has been reported to trigger endothelial "gap" formation and tyrosine phosphorylation of an unidentified 130-kDa protein. We have studied two 130-kDa junctional adhesion molecules, CD31 and VE-cadherin, in porcine aortic endothelial cells (PAECs) during IB4-mediated activation. The cellular distribution of these molecules, their susceptibility to tyrosine phosphorylation, and their capacity to bind IB4 or natural human antibodies have been determined. METHODS: Porcine CD31 and VE-cadherin were cloned. Recombinant proteins and monoclonal antibodies were prepared. The distribution and phosphorylation of CD31 and VE-cadherin in confluent PAECs activated with IB4 or human serum were studied by confocal microscopy and Western blotting, respectively. RESULTS: IB4 caused rapid redistribution of CD31 and VE-cadherin away from cell junctions and tyrosine-phosphorylation of CD31 but not VE-cadherin. A monoclonal antibody to CD31 also triggered tyrosine phosphorylation of this molecule, but brief exposure of PAECs to normal human serum did not. Tyrosine-phosphorylated CD31 complexed with SHP2 and other unidentified phosphoproteins. Both IB4 and natural human antibodies bound to porcine CD31 but not to VE-cadherin. Cell adhesion tests showed that porcine and human CD31 are functionally incompatible. CONCLUSIONS: Endothelial cell retraction during IB4-mediated activation of PAECs is associated with rapid loss of CD31 and VE-cadherin from cell junctions. CD31 becomes strongly tyrosine-phosphorylated and forms a cell signaling complex, which may have a significant role in the response of the xenograft vascular endothelium.     

Alterations of Circulating Bone Marrow–Derived VEGFR-2+ Progenitor Cells in Isolated Limb Perfusion With or Without rhTNF-α

Background

Circulating endothelial progenitor cells (cEPCs) as recruited to the angiogenic vascular system of malignant tumors have been proposed as a biomarker in malignancies. The effect of antitumor chemotherapy on cEPCs is not fully understood. We examined the level of cEPCs, vascular endothelial growth factor (VEGF), and angiopoietin-2 in the blood of sarcoma and melanoma patients before and after isolated limb perfusion (ILP) with or without recombinant human tumor necrosis factor-α (rhTNF-α).

Methods

Twenty-two patients, 11 each with soft tissue sarcoma or recurrent melanoma of the limb, were recruited. ILP was performed with rhTNF-α/melphalan (TNF) or melphalan only (no TNF). Fifteen healthy volunteers served as control subjects. Blood was sampled before and up to 6 weeks after ILP. Peripheral blood mononuclear cells were isolated by density gradient centrifugation, and annexin V-negative cells were characterized as cEPCs by triple staining for CD133⁺, CD34, and VEGFR-2⁺.

Results

Before treatment, cEPC numbers were significantly increased in sarcoma (0.179 ± 0.190 %) and melanoma patients (0.110 ± 0.073 %) versus healthy controls (0.025 ± 0.018 %; P < 0.01), but did not differ significantly between sarcoma and melanoma patients. cEPC decreased significantly after ILP in patients with no TNF compared to pretreatment values (P < 0.05) and were significantly lower at 4 h, 48 h, and 1 week compared to ILP with TNF (P < 0.05). Values 6 weeks after ILP were significantly lower than before ILP in both investigated groups (P < 0.01).

Conclusions

ILP with TNF results in activation of bone marrow–derived EPCs compared to ILP without TNF. Alteration of cEPCs and angiopoietin-2 by rhTNF-α might account for the cytotoxicity and hemorrhagic effects on tumor vessels during limb perfusion procedures.     

Acidosis plus melphalan induces nitric oxide-mediated tumor regression in an isolated limb perfusion human melanoma xenograft model

BACKGROUND: Isolated limb perfusion (ILP) with melphalan is an accepted treatment for intransit melanoma of the extremities. Using an ILP human melanoma xenograft model, we tested the hypothesis that acidosis augments the antitumor effect of melphalan and that nitric oxide (NO) induction mediates tumor regression. METHODS: NIH1286 human melanoma tumor bearing athymic nude rats underwent a 10-minute ILP. Group C was perfused at physiologic pH without acid or melphalan, group M received melphalan at physiologic pH (7.2), group A received 0.2 N of HCl at pH 6.8, and group A/M received melphalan and HCl at pH 6.8. Groups 1400W + A and 1400W + A/M were injected with 1400W, a specific inhibitor of inducible NO synthase, 1 hour pre-ILP. Tumor response was followed for up to 60 days in all survival experiments. In 4 to 6 animals from groups C, M, A, and A/M, tumor NO was measured pre- and post-ILP, and tumor and thigh muscle from 2 additional animals in each group were collected at 20 minutes and 24 hours post-ILP and processed for terminal deoxynucleotidyl transferase dUTP nick end labeling staining. RESULTS: Maximum mean reduction in tumor size after ILP in the different groups was as follows: C = 0%, M = 55%, A = 99.6% (3 of 4 complete responses), A/M = 100% (all complete responses), 1400W + A = 0%, and 1400W + A/M = 25%. Median tumor NO was 0.87 +/- 0.74 (SD) micromol/L before ILP and increased significantly (Mann-Whitney rank sum test, P <.001) after ILP (C = +6.9%, n = 4; M = +7.5%, n = 5; A = +66.0%, n = 6; A/M = +35.9%, n = 6). Also, minimal apoptotic cell death was seen in C and M, whereas A and A/M showed evidence of widespread apoptosis. CONCLUSIONS: Acidosis enhances the antitumor effect of melphalan. NO induction appears to play a role in tumor regression.     

Isolated perfusion of the kidney with tumor necrosis factor for localized renal-cell carcinoma

Summary Patients with localized renal-cell carcinoma who are candidates for renal parenchymal sparing surgery are being treated with isolated renal perfusion with recombinant human tumor necrosis factor (TNF). Isolated organ perfusion is a surgical technique that allows a cancer-bearing organ or region of the body to be treated with high doses of chemotherapy or biologic, agents that would not be tolerated systemically. In patients with in-transit melanoma or unresectable sarcoma, treatment with hyperthermic isolated limb perfusion using TNF, interferon-, and melphalan has resulted in response rates exceeding 90%. Because preclinical studies suggest that TNF may induce regression of tumors by causing hemorrhagic necrosis mediated by effects on tumor-related vascular endothelium, a vascular tumor such as renal-cell carcinoma could potentially be very responsive. A phase I study of escalating TNF doses delivered via isolated renal perfusion is currently being conducted.     

Mechanisms of HER2-Induced Endothelial Cell Retraction

Background HER2 overexpression imparts a metastatic advantage in breast cancer. We have shown that HER2 signaling in breast cancer cells induces adjacent endothelial cell (EC) retraction, disrupting endothelial integrity. Because endothelial integrity is dependent on the adherens junctions, we postulated that the mechanism of tumor cell-induced EC retraction involves dissociation of catenin proteins from vascular endothelial (VE) cadherin. In this study, we report a loss of VE-cadherin in tumor-associated EC. We also tested for a change of catenin dissociation from VE-cadherin by manipulating HER2 signaling in tumor cells. Methods We tested confluent monolayers of human EC for downregulation of VE cadherin and dissociation of catenins from VE cadherin after exposure to breast cancer cells or conditioned media. Using immunoprecipitation, we quantitated the remaining complexed catenins to VE-cadherin in tumor-associated EC after different treatments to manipulate HER2 signaling. Results Treatment of EC with conditioned media from MCF-7 cells expressing HER2 induced a loss of VE-cadherin expression, and time-dependent dissociation of catenins from VE cadherin. Catenin dissociation from VE-cadherin was enhanced by Heregulin β1 (P < .05) stimulation and decreased by trastuzumab (P < .05) blockade of HER2 signaling in cancer cells. An increase in EC phosphoSrc (Tyr 416) was seen by 8 hours. Conclusions Our data suggest that HER2 induction of EC retraction involves both down-regulation of VE-cadherin and dissociation of catenins. HER2 signaling appears to regulate this potential metastatic mechanism. Further, Src phosphorylation suggests that this pathway may be involved in this mechanism.     

Vascular endothelial growth factor (VEGF121) protects rats from renal infarction in thrombotic microangiopathy

BACKGROUND: Renal thrombotic microangiopathy, typified by the hemolytic uremic syndrome, is associated with endothelial cell injury in which the presence of cortical necrosis, extensive glomerular involvement, and arterial occlusive lesions correlates with a poor clinical outcome. We hypothesized that the endothelial survival factor vascular endothelial growth factor (VEGF) may provide protection. METHOD: Severe, necrotizing, thrombotic microangiopathy was induced in rats by the renal artery perfusion of antiglomerular endothelial antibody, followed by the administration of VEGF or vehicle, and renal injury was evaluated. RESULTS: Control rats developed severe glomerular and tubulointerstitial injury with extensive renal necrosis. The administration of VEGF significantly reduced the necrosis, preserved the glomerular endothelium and arterioles, and reduced the number of apoptotic cells in glomeruli (at 4 hours) and in the tubulointerstitium (at 4 days). The prosurvival effect of VEGF for endothelium may relate in part to the ability of VEGF to protect endothelial cells from factor-induced apoptosis, as demonstrated for tumor necrosis factor-alpha (TNF-alpha), which was shown to be up-regulated through the course of this model of renal microangiopathy. Endothelial nitric oxide synthase expression was preserved in VEGF-treated rats compared with its marked decrease in the surviving glomeruli and interstitium of the antibody-treated rats that did not receive VEGF. CONCLUSIONS: VEGF protects against renal necrosis in this model of thrombotic microangiopathy. This protection may be mediated by maintaining endothelial nitric oxide production and/or preventing endothelial cell death.     

Isolated hypoxic hepatic perfusion with tumor necrosis factor-alpha, melphalan, and mitomycin C using balloon catheter techniques: a pharmacokinetic study in pigs.

OBJECTIVE: To validate the methodology of isolated hypoxic hepatic perfusion (IHHP) using balloon catheter techniques and to gain insight into the distribution of tumor necrosis factor-alpha (TNF), melphalan, and mitomycin C (MMC) through the regional and systemic blood compartments when applying these techniques. SUMMARY BACKGROUND DATA: There is no standard treatment for unresectable liver tumors. Clinical results of isolated limb perfusion with high-dose TNF and melphalan for the treatment of melanoma and sarcoma have been promising, and attempts have been made to extrapolate this success to the isolated liver perfusion setting. The magnitude and toxicity of the surgical procedure, however, have limited clinical applicability. METHODS: Pigs underwent IHHP with TNF, melphalan, and MMC using balloon catheters or served as controls, receiving equivalent dosages of these agents intravenously. After a 20-minute perfusion, a washout procedure was performed for 10 minutes, after which isolation was terminated. Throughout the procedure and afterward, blood samples were obtained from the hepatic and systemic blood compartments and concentrations of perfused agents were determined. RESULTS: During perfusion, locoregional plasma drug concentrations were 20- to 40-fold higher than systemic concentrations. Compared with systemic concentrations after intravenous administration, regional concentrations during IHHP were up to 10-fold higher. Regional MMC and melphalan levels steadily declined during perfusion, indicating rapid uptake by the liver tissue; minimal systemic concentrations indicated virtually no leakage to the systemic blood compartment. During isolation, concentrations of TNF in the perfusate declined only slightly, indicating limited uptake by the liver tissue; no leakage of TNF to the systemic circulation was observed. After termination of isolation, systemic TNF levels showed only a minor transient elevation, indicating that the washout procedure at the end of the perfusions was fully effective. CONCLUSIONS: Complete isolation of the hepatic vascular bed can be accomplished when performing IHHP using this balloon catheter technique. Thus, as in extremities, an ideal leakage-free perfusion of the liver can now be performed, and repeated, without major surgery. The effective washout allows the addition of TNF in this setting.     

肿瘤坏死因子-α对血管内皮细胞通透性影响的实验研究

目的：观察人肿瘤坏死因子-α（TNF—α）对人血管内皮细胞（EA.hy926）单层通透性的影响并初步探讨其作用机制。方法：测定异硫氰酸荧光素（FITC）标记的葡聚糖透过Transwell小室的荧光强度,以表示EA．hy926细胞单细胞层的通透性大小;激光共聚焦显微镜观察细胞骨架肌动蛋白（F—actin）和血管内皮钙黏蛋白（VE—cadherin）的形态分布;蛋白免疫印迹检测钙黏蛋白的表达。结果：与对照组比较,TNF-α使EA.hy926内皮细胞的通透性明显增加（P〈0．05）,诱导肌动蛋白重新分布及应力纤维形成,并使钙黏蛋白排列紊乱、断裂、细胞问裂隙形成增多。免疫印迹检测表明TNF-α减少钙黏蛋白表达呈剂量和时间依赖性。结论：TNF-α诱导内皮细胞通透性增高,其机制可能与其破坏内皮细胞屏障功能的完整性有关。     

Quiescent interplay between inducible nitric oxide synthase and tumor necrosis factor-alpha: influence on transplant graft vasculopathy in renal allograft dysfunction

A healthy endothelium is essential for vascular homeostasis, and preservation of endothelial cell function is critical for maintaining transplant allograft function. Damage to the microvascular endothelial cells is now regarded as a characteristic feature of acute vascular rejection, an important predictor of graft loss. It is also linked with transplant vasculopathy, often associated with chronic allograft nephropathy. Large bursts of nitric oxide in infiltrating monocytes/macrophages modulated by inducible nitric oxide synthase are considered pivotal in driving this mechanism. Indeed, it has been shown recently that increased circulating levels of tumor necrosis factor-alpha in the rejecting kidneys are largely responsible for triggering inducible nitric oxide synthase expression. This in turn suggests that several structural and functional features of graft rejection could be mediated by tumor necrosis factor-alpha. Despite the large body of evidence that supports immunologic involvement, knowledge concerning the cellular and biochemical mechanisms for nephritic cell dysfunction and death is incomplete. The role of tumor necrosis factor-alpha in mediating pathophysiological activity of inducible nitric oxide synthase during transplant vasculopathy remains contentious. Here, we discuss the effect of inducible nitric oxide synthase and tumor necrosis factor-alpha interaction on progressive damage to glomerular and vascular structures during renal allograft rejection. Selective inhibition of inducible nitrous oxide synthase and tumor necrosis factor-alpha as a potential therapy for ameliorating endothelial dysfunction and transplant graft vasculopathy is also discussed.     

Effect of aprotinin on endothelial cell activation.

BACKGROUND: Cardiopulmonary bypass surgery is often accompanied by a systemic inflammatory response, which can lead to postoperative complications in high-risk patients. This is mediated in part through a systemic rise in inflammatory cytokine levels and the sequestration of leukocytes within organs. Aprotinin has previously been shown to exert an anti-inflammatory effect by preventing the capacity of leukocytes to transmigrate through vascular endothelium. Here we have focused on whether aprotinin has an effect on endothelial cell activation and adhesion molecule expression in response to tumor necrosis factor-alpha, particularly with reference to whether aprotinin inhibits tumor necrosis factor-stimulated neutrophil transendothelial migration.Methods and Results: Intercellular adhesion molecule-1, vascular cell adhesion molecule-1, and E-selectin expression was studied in tumor necrosis factor-alpha-activated human umbilical vein endothelial cells in the presence of aprotinin at 200, 800, and 1600 kIU/mL. Aprotinin inhibited tumor necrosis factor-alpha-stimulated expression of intercellular adhesion molecule-1 (P =.019 at 1600 kIU/mL) and vascular cell adhesion molecule-1 (P =.003 at 1600 kIU/mL) but not E-selectin. Similar results were obtained in the dermal microvascular endothelial cell line, HMEC-1, which exhibited diminished intercellular adhesion molecule-1 expression in the presence of aprotinin (P =.040 at 800 kIU/mL and P <.001 at 1600 kIU/mL). Aprotinin also significantly inhibited neutrophil transmigration across tumor necrosis factor-alpha-activated human umbilical vein endothelial cells (P =.046 at 1600 kIU/mL). CONCLUSIONS: We have demonstrated that aprotinin inhibits intercellular adhesion molecule-1 and vascular cell adhesion molecule-1, but not E-selectin, expression on tumor necrosis factor-alpha-activated endothelial cells and that transendothelial migration by neutrophils is also specifically suppressed under these conditions. Our results indicate that endothelial cells can be specifically targeted by aprotinin, therefore adding to our understanding of the anti-inflammatory mechanism of action of aprotinin during cardiopulmonary bypass.     

Isolated limb perfusion for unresectable melanoma of the extremities

HYPOTHESIS: In patients with truly unresectable melanoma of the extremities, results after isolated limb perfusion (ILP) are absent in the literature. Complete response rates are probably lower than the reported 54% for locoregional recurrent melanoma. In these patients, ILP with melphalan and tumor necrosis factor alpha (TNF-alpha) could be superior to ILP with melphalan alone. DESIGN: Retrospective analysis with a median follow-up period of 21 months (interquartile range, 9-40 months). SETTING: Two tertiary care cancer centers in the Netherlands. PATIENTS: We assessed all 130 consecutive patients who underwent ILP for unresectable melanoma of the extremities, performed between 1978 and 2001. Of these patients, 38% had stage IIIA melanoma and 45% had stage IIIAB melanoma according to criteria of the MD Anderson Cancer Center. Lesions were considered unresectable on the basis of their size, number, or localization. INTERVENTIONS: Forty ILPs were performed with melphalan, and 90 were done with TNF-alpha and melphalan. MAIN OUTCOME MEASURES: Response rate, disease-free survival, limb salvage rate, and overall survival. RESULTS: In 45% of the patients, a complete response was attained after ILP with melphalan (95% confidence interval, 29%-61%) compared with 59% after ILP with TNF-alpha and melphalan (95% confidence interval, 49%-69%; P = .14). The time to complete response was 3 months (interquartile range, 2-6 months) vs 2 months (interquartile range, 1-3 months; P = .01), respectively. The recurrence rate and median limb recurrence-free survival were not significantly different for both ILP types. The overall limb salvage rate was 96%. Overall 5-year survival was 29% (95% confidence interval, 20%-38%). The ILP type was not an independent prognostic factor for complete response, nor was limb recurrence-free survival, whereas stage IIIA was a favorable prognostic factor (P = .01 and P = .02, respectively). Favorable prognostic factors for improved survival were complete response (P<.001) and a tumor size of 3 cm or less (P = .01). CONCLUSIONS: In more than half of the patients with truly unresectable melanoma of the extremities, a complete response was obtained after ILP with melphalan with or without TNF-alpha. The ILP type was not an independent prognostic factor for complete response, limb recurrence-free survival, or overall survival.     

Marked variability of melphalan plasma drug levels during regional hyperthermic isolated limb perfusion

BACKGROUND: Hyperthermic isolated limb perfusion (HILP) with melphalan as treatment for locally recurrent or in-transit malignant melanoma is frequently performed but the principle for calculating drug dosage remains poorly understood. METHODS: This study examined the pharmacokinetic profile of 14 consecutive patients to determine what variables were associated with toxicity and tumor responses. RESULTS: Marked fourfold variability was noted in patient plasma melphalan concentrations. We defined a factor--the ratio of estimated limb volume (Vesti) to melphalan volume of distribution (Vss), Vesti/Vss--that was much more strongly correlated with acute regional toxicity than either area under concentration-time curve or peak plasma concentration. In addition, we found that AUX2 was the best correlate of tumor response. CONCLUSIONS: Pharmacokinetic evaluation of prospective HILP trials is critical to not only understand response and toxicity outcomes but also to potentially improve the therapeutic index of regional perfusion.     

Organ Preservation Solutions Increase Endothelial Permeability and Promote Loss of Junctional Proteins

OBJECTIVE: To investigate the effects of the organ preservation solutions UW and Plegisol on endothelial permeability; occludin and vascular endothelial (VE)-cadherin content in human umbilical vein endothelial cells (HUVEC); and junctional localization of these proteins after exposure to these solutions. SUMMARY BACKGROUND DATA: Organ preservation for transplantation is limited by several challenges, including loss of tissue function, tissue injury, and tissue edema. Occludin and VE-cadherin are responsible for maintaining and regulating the endothelial solute barrier. Several studies have noted organ edema and dysfunction with preservation, as well as gaps between endothelial cells suggesting that disorganization of junctional proteins (e.g., occludin and VE-cadherin) is responsible for interstitial edema. METHODS: HUVEC monolayers were treated with 4 degrees C UW and Plegisol for 3 and 6 hours and then reperfused with normal buffer. Permeability was examined using FITC-dextran tracer during the reperfusion phase. Occludin and VE-cadherin content at different time points was measured by Western blotting. Treated groups were also examined by immunofluorescence for occludin, VE-cadherin, and F-actin. RESULTS: Compared with untreated controls, cold preservation for 3 and 6 hours increased endothelial permeability after rewarming, which appears to depend on the duration of cold exposure. Monolayers exposed to 3 hours of cold preservation did not have increased permeability in the first hour after rewarming but had significantly increased permeability after the first hour and all subsequent time points. Monolayers exposed to 6 hours of cold preservation had increased permeability after the first hour and at all later time points. Western blotting demonstrated that occludin content was decreased to a similar extent with all solutions after 3 hours of cold preservation. Six hours of cold preservation in Plegisol reduced the occludin content significantly compared with UW and control. VE-cadherin content was unchanged after 3 hours of cold preservation but was dramatically reduced in all groups at 6 hours. Immunofluorescent staining demonstrated junctional gap formation and discontinuous staining of occludin and VE-cadherin with all cold preservation protocols; changes in F-actin organization were observed at 3 and 6 hours after cold preservation. CONCLUSION: The changes in occludin, VE-cadherin, and F-actin content and organization and increased permeability associated with cold storage demonstrate that alterations of the tight and adherens junctions may underlie organ edema associated with cold organ preservation. These data also suggest that novel strategies to maintain the content and integrity of endothelial junctional proteins may provide an important therapeutic avenue for organ preservation.     

Metaiodobenzylguanidine and Hyperglycemia Augment Tumor Response to Isolated Limb Perfusion in a Rodent Model of Human Melanoma

Background: Perfusate acidification with dilute hydrochloric acid augments tumor response rates in a rodent model of isolated limb perfusion (ILP). This study investigates the combination of metaiodobenzylguanidine (MIBG), a mitochondrial inhibitor, and systemic hyperglycemia as a strategy to selectively acidify tumors and thereby sensitize them to ILP.Methods: Human melanoma xenografts were implanted into the hind limbs of athymic rats. When tumors reached 12 to 15 mm in diameter, animals were randomized to ILP with or without melphalan, with or without systemic MIBG, and hyperglycemia of 485 ± 35 mg/dL. Intratumoral pH was measured during MIBG and glucose treatment by using magnetic resonance spectroscopy.Results: MIBG at 30 mg/kg plus hyperglycemia decreased intracellular pH by .6 units and extracellular pH by .8 units. MIBG at 22.5 mg/kg plus hyperglycemia decreased intracellular and extracellular pH by .4 and .5 units, respectively. Tumor growth was unaffected by systemic MIBG and hyperglycemia alone. When MIBG at 30 mg/kg and hyperglycemia were combined with ILP, tumor growth was delayed for 33 days after control ILP and for 44 days after melphalan ILP. However, this dose of MIBG was complicated by a 40% mortality rate after ILP. MIBG at 22.5 mg/kg, in combination with MIBG in the perfusate, did not cause mortality and delayed tumor growth by 51 days after melphalan ILP.Conclusions: MIBG and hyperglycemia improve tumor response rates after ILP in a rodent model of human melanoma. Selective tumor acidification with MIBG and hyperglycemia may offer added benefit to current regional perfusion strategies.