Anatomic resection to manage donor partial anomalous pulmonary venous return during lung transplantation: a case report and review

INTRODUCTION

Rare vascular malformations are discovered infrequently in donor lungs before implantation into recipients. However, the proper handling of such malformations can influence ischemic time, implantation strategies, and subsequent patient outcomes.

CASE REPORT

We report a simplified method for addressing the technical challenges of anomalous pulmonary venous return in a donor lung before implantation.

CONCLUSIONS

We demonstrate that anatomic resection is a safe and efficient method for managing this rare congenital vascular malformation.

Bile acid aspiration associated with lung chemical profile linked to other biomarkers of injury after lung transplantation

Aspiration of gastrointestinal contents has been linked to worse outcomes following lung transplantation but uncertainty exists about underlying mechanisms. We applied high-resolution metabolomics of bronchoalveolar lavage fluid (BALF) in patients with episodic aspiration (defined by bile acids in the BALF) to identify potential metabolic changes associated with aspiration. Paired samples, one with bile acids and another without, from 29 stable lung transplant patients were studied. Liquid chromatography coupled to high-resolution mass spectroscopy was used to interrogate metabolomic contents of these samples. Data were obtained for 7068 ions representing intermediary metabolites, environmental agents and chemicals associated with microbial colonization. A substantial number (2302) differed between bile acid positive and negative samples when analyzed by false discovery rate at q = 0.01. These included pathways associated with microbial metabolism. Hierarchical cluster analysis defined clusters of chemicals associated with bile acid aspiration that were correlated to previously reported biomarkers of lung injury including T cell granzyme B level and the chemoattractants CXCL9 and CXCL10. These data specifically link bile acids presence in lung allografts to inflammatory pathways known to segregate with worsening allograft outcome, and provide additional mechanistic insight into the association between reflux and lung allograft injury.

Cumulative exposure to gamma interferon-dependent chemokines CXCL9 and CXCL10 correlates with worse outcome after lung transplant

Outcomes following lung transplant are suboptimal owing to chronic allograft failure termed bronchiolitis obliterans syndrome (BOS). Prior work in both mice and humans has shown that interferon gamma (IFNG)-induced chemokines, including CXCL9 and CXCL10, are elevated in patients with established BOS. We hypothesized that patients who ultimately developed BOS would have elevations in these chemokines before losing lung function. We utilized a high throughput multiplex enzyme-linked immunosorbent assay (ELISA) to measure biomarkers in bronchoalveolar lavage fluid (BALF). We modeled cumulative exposure to seven biomarkers (CXCL9, CXCL10, RANTES, IL1-RA, IL-17, MCP1 and IL-13) by calculating the 1-year area under the curve (AUC) for each biomarker in the BALF of 40 lung transplant patients who had at least four samples obtained in the first year posttransplant. Cumulative elevations in CXCL9 and CXCL10 were associated with a significant risk of subsequent graft failure after transplant (HR 9.37 and 5.52, respectively; p < 0.01 for both). Further these chemokines were also elevated in patients before the onset of BOS. CXCL9 and CXCL10 elevations were seen between 3 and 9 months before graft failure. Our data show that persistent presence of CXCL9 and CXCL10 portents worsening lung allograft function; measuring these IFNG-induced chemokines might prospectively identify patients at risk for BOS.

Gastroesophageal reflux disease is associated with an increased rate of acute rejection in lung transplant allografts

PURPOSE

Gastric fundoplication (GF) for gastroesophageal reflux disease (GERD) may protect against the progression of chronic rejection in lung transplant (LT) recipients. However, the association of GERD with acute rejection episodes (ARE) is uncertain. This study sought to identify if ARE were linked to GERD in LT patients.

METHODS

This single-center retrospective observational study, of patients transplanted from January 1, 2000, to January 31, 2009, correlated results of pH probe testing for GERD with ARE (≥International Society for Heart and Lung Transplantation A1 or B1). We compared the rates of ARE among patients with GERD (DeMeester Score > 14.7) versus without GERD as number of ARE per 1,000 patient-days after LT. Patients undergoing GF prior to LT were excluded.

RESULTS

The analysis included 60 LT subjects and 9,249 patient-days: 33 with GERD versus 27 without GERD. We observed 51 ARE among 60 LT recipients. The rate of ARE was highest among patients with GERD: 8.49 versus 2.58, an incidence density ratio (IDR) of 3.29 (P = .00016). Upon multivariate negative binomial regression modeling, only GERD was associated with ARE (IDR 2.15; P = .009). Furthermore, GERD was associated with multiple ARE (36.4% vs 0%; P < .0001) and earlier onset compared with patients without GERD: ARE proportion at 2 months was 0.55 versus 0.26 P = .004).

CONCLUSION

In LT recipients, GERD was associated with a higher rate, multiple events, and earlier onset of ARE. The efficacy of GF to reduce ARE among patients with GERD needs further evaluation.

Inclusion of the herpes simplex thymidine kinase gene in a replicating adenovirus does not augment antitumor efficacy

Replication-incompetent adenoviruses (Ad) carrying the herpes simplex thymidine kinase (HSVtk) gene have been used in a number of human cancer gene therapy trials, however transduction has generally been limited to a small minority of tumor cells. To solve this problem, replication-competent adenoviral vectors carrying transgenes such as HSVtk have been developed. However, contradictory evidence exists regarding the efficacy of these new vectors. Accordingly, we constructed and tested a replication-competent E3-deleted adenoviral vector containing the HSVtk suicide gene driven by the endogenous E3 promoter (Ad.wt.tk). This virus showed high level production of the HSVtk transgene and was more efficacious than a non-replicating virus in vitro, after injection into flank tumors, and against established intraperitoneal tumors. However, addition of ganciclovir (GCV) therapy to cells or tumor-bearing animals treated with the replicating vector containing the HSVtk suicide gene did not result in increased cell killing. Our results indicate that addition of HSVtk to a replicating Ad virus will not likely be useful in augmenting antitumor effects.

Efficacy of repeated adenoviral suicide gene therapy in a localized murine tumor model

BACKGROUND

Gene therapy using adenovirus to deliver herpes simplex virus thymidine kinase (Ad.HSVtk) followed by the administration of the prodrug ganciclovir has been an effective anticancer therapy in models of localized tumor (including malignant mesothelioma) and is currently being evaluated in clinical trials. To optimize this approach, we studied the effects of repeated injections of Ad.HSVtk in an animal model of localized tumor in both naive and immunized mice.

METHODS

Immunocompetent animals with established abdominal tumor were treated with either one or three (given weekly) intraperitoneal injections of Ad.HSVtk (10(9) plaque-forming units) followed by daily ganciclovir and monitored for survival. Survival studies were also performed in mice previously immunized with adenovirus.

RESULTS

Animals treated with multiple courses of Ad.HSVtk showed significantly improved survival versus singly injected animals and control animals with some long-term survivors in the multiple injected group. Preexisting neutralizing immunity did not diminish this survival advantage.

CONCLUSIONS

Multiple treatments using an adenoviral vector to deliver HSVtk significantly improves survival in a murine intraperitoneal tumor model. The presence of preexisting neutralizing antibodies does not blunt this effect. Repeat Ad.HSVtk is a feasible approach and may be a useful strategy in human cancer gene therapy.

Cationic lipid:bacterial DNA complexes elicit adaptive cellular immunity in murine intraperitoneal tumor models

Previous studies with a mycobacterial heat shock protein (hsp-65) have demonstrated some efficacy using cationic liposome-mediated gene transfer in murine i.p. sarcoma models. To further analyze the efficacy of hsp-65 immunotherapy in clinically relevant models of localized cancer, immunocompetent mice bearing i.p. murine mesothelioma were treated with four i.p. doses of a cationic lipid complexed with plasmid DNA (pDNA) containing hsp65, LacZ, or a null plasmid. We observed >90% long-term survival (median survival, 150 days versus approximately 25 days, treated versus saline control, respectively) in a syngeneic, i.p. murine mesothelioma model (AC29). Long-term survivors were observed in all groups treated with lipid complexed with any pDNA. Lipid alone or DNA alone provided no demonstrable survival advantage. In a more aggressive i.p. model of mesothelioma (AB12), we observed >40% long-term survival in groups treated with lipid:pDNA complexes, again irrespective of the transgene. To ask whether these antitumor effects had led to an adaptive immune response against the tumor cell, we rechallenged long-term survivors in both murine models s.c. with the parental tumor cell line. Specific, long-lasting systemic immunity against the tumor was readily demonstrated in both models (AB12 and AC29). Consistent with these results, splenocytes from long-term survivors specifically lysed the parental tumor cell lines. Depleting the CD8+ T-cells from the splenocyte pool eliminated this lytic activity. Lipid:pDNA treatment of athymic, SCID, and SCID/Beige mice bearing a murine i.p. mesothelioma (AC29) resulted in only a slight survival advantage, but there were no long-term survivors. Treatment of immunocompetent mice depleted of specific immune effector cells demonstrated roles for CD8+ and natural killer cells. Although the exact mechanism(s) responsible for these antitumor effects is unclear, the results are consistent with roles for both innate and adaptive immune responses. An initial tumor cell killing stimulated by cationic lipid:pDNA complexes appears to be translated into long-term, systemic immunity against the tumor cell. These results are the first to demonstrate that adaptive immunity against a tumor cell can be induced by the administration of lipid:pDNA complexes. Multiple administrations of cationic lipid complexed with pDNA lacking an expressed transgene could provide a promising generalized immune-mediated modality for treating cancer.

A rapid and sensitive method for the quantification of ganciclovir in plasma using liquid chromatography/selected reaction monitoring/mass spectrometry

A method using reversed-phase liquid chromatography coupled with electrospray ionization and selected reaction monitoring mass spectrometry has been developed for the quantitative analysis of ganciclovir in rat plasma. Acyclovir, a structurally related analog of ganciclovir, was used as the internal standard. A small volume of plasma (50 microL) was spiked with the internal standard and plasma proteins were precipitated by methanol. The supernatant was dried under nitrogen, and then reconstituted in water. The use of liquid chromatography/selected reaction monitoring/mass spectrometry effectively eliminated potential interference from endogenous constituents in the plasma. This highly selective and sensitive method made it possible to analyze plasma ganciclovir with a lower limit of quantitation of 10 ng/mL. The assay was reproducible and linear in the range 10-10,000 ng/mL. The precision and accuracy values were in the range 2.0-6.9% and 89.0-109.6%, respectively. The analyte recovery was greater than 88%. This method was successfully used to monitor the pharmacokinetic profile of ganciclovir in normal rats following intraperitoneal administration of the drug.

Evaluation of an E1E4-deleted adenovirus expressing the herpes simplex thymidine kinase suicide gene in cancer gene therapy

Studies with first-generation adenoviral vectors have uncovered limitations that include finite transgene persistence, potential hepatotoxicity, and contamination with replication-competent adenovirus (RCA). To address these limitations within the context of cancer suicide gene therapy, a new adenoviral vector was developed containing the herpes simplex virus type 1 thymidine kinase (HSV tk) gene inserted in the E1 region of a recombinant vector containing deletions in the E1 and E4 regions of the Ad5 genome. The HSV tk minigene was placed under transcriptional control of a Rous sarcoma virus (RSV) promoter. This new E1E4-deleted vector was compared with the first-generation E1E3-deleted Ad.RSVtk vector. Generation of replication-competent adenovirus during production was eliminated. Using semiquantitative immunoblotting, the two vectors produced equivalent amounts of the expected 44-kDa tk-encoded protein in three different cell lines tested. The ability of the E1E4-deleted vector to sensitize tumor cells to ganciclovir (GCV) using in vitro assays and mixing studies was comparable to that of the E1E3-deleted vector. In vivo bystander effects were investigated using mixing studies in a syngeneic flank tumor model and demonstrated no difference between vectors in either immunocompetent or immunodeficient mice. To test the efficiency of these vectors in treating tumors in clinically relevant models, virus was injected intraperitoneally into tumor-bearing SCID mice and intrapleurally in a syngeneic rat mesothelioma model. After treatment of animals with ganciclovir, both vectors were roughly equivalent in their ability to increase mean survival (from approximately 40 to approximately 70 days) and markedly reduce tumor burden. Finally, formal toxicology studies were performed and showed similar amounts of local inflammation without systemic toxicity. In summary, this series of in vitro and in vivo experiments indicates that the performance of the recombinant E1E4-deleted adenoviral vector was virtually identical to that of the E1E3-deleted vector. Since the E1E4 vector has a much lower rate of recombination during production and has been shown to be less hepatotoxic in animal models, this new vector should prove superior to the first-generation Ad.HSVtk vectors in clinical cancer gene therapy trials.

Analysis of regional hemodynamic regulation in response to scald injury

Ultrasonic probes were placed around dog femoral arteries to record blood flow. Hind paw scalding with boiling water (5 s) caused a marked increase in ipsilateral femoral blood flow that persisted for the 2-h observation period. Contralateral femoral blood flow and systemic and pulmonary vascular resistances were unchanged. Compared to scald only animals, methysergide pretreatment diminished and shortened the femoral vasodilator response to scald (109 +/- 14 vs 243 +/- 27 ml/min at 5 min; 59 +/- 14 vs 191 +/- 31 ml/min at 2 h). Pretreatment with ritanserin, BW A1433U83, atropine, ICI 118551, diphenhydramine, ranitidine, meclofenamate, L-nitro-arginine methyl ester, 3-amino-1,2,4-triazine, and U 37883A had no effect on the increased femoral blood flow response to scald, suggesting this vasodilator response is not dependent upon activation of serotonergic2, adenosineA1, muscarinic, beta 2-adrenergic, histaminergic1 or histaminergic2 receptors, on cyclooxygenase products, endothelium-derived relaxing factor derived from nitric oxide (NO) synthase III, NO derived from NO synthase II, or KATP channels, respectively. Methysergide given after burn immediately reduced the augmented femoral blood flow to preburn levels, suggesting the vasodilator response to scald is mediated through continual activation of local serotonergic1-like receptors, which may be target site(s) for therapeutic interventions to influence burn-induced hemodynamic alterations.

Heparin treatment enhances the recovery of neoendothelial acetylcholine-induced vascular relaxation after balloon catheter injury in the rabbit aorta

BACKGROUND

After catheter injury, the neoendothelium that grows is abnormal in morphology and in acetylcholine-induced generation of endothelium-derived relaxing factor (EDRF). Heparin has been shown to have stimulatory effects on vascular endothelial growth in vitro. Its effect in vivo on neoendothelial cell morphology and metabolism after injury has not been described. We investigated the effect of heparin treatment on the neoendothelium formed after injury.

METHODS AND RESULTS

Four groups of New Zealand White rabbits were studied. Group 1 rabbits underwent catheter denudation and were killed 4 weeks after injury without receiving treatment (NO Tx, n = 8). Groups 2 and 3 underwent similar aortic injury, received 2 weeks of treatment with either heparin (n = 7) or low molecular weight heparin (LMWH, n = 5), and were killed at 4 weeks. Group 4 underwent sham operation (SHAM, n = 8). EDRF generation was determined by the relaxation of precontracted aortic rings in an organ bath in response to acetylcholine. The heparin-treated group exhibited a significant improvement in acetylcholine-induced relaxation (27%) versus both LMWH-treated (14%, P = .035) and untreated groups (11%, P = .004), although relaxation was only 50% of that observed in the uninjured control vessels (52%, P = .001). The neoendothelium formed in the heparin-treated group exhibited a more normal histological appearance and was aligned with the direction of blood flow as compared with that observed in the untreated or LMWH-treated groups.

CONCLUSIONS

These results demonstrate that in vivo heparin administration enhanced the recovery of EDRF generation and augmented normalization of the morphologic appearance of the neoendothelium.