Samuel Kim

Enhanced In Vivo Function of Bioartificial Lungs in Rats

BACKGROUND More than 11 million Americans live with chronic lung disease; in search for an alternative to donor organs, we attempted to regenerate lungs based on perfusion decellularized lung scaffolds that can be transplanted similar to a donor organ. METHODS Cadaveric rat lungs were decellularized by detergent perfusion. Resulting scaffolds were mounted in bioreactors and seeded with endothelial and fetal lung cells. Biomimetic organ culture was maintained for 7 days. Resulting bioartificial left lungs were transplanted in orthotopic position after left pneumonectomy in rats. Cadaveric left lung transplants and pneumonectomies served as controls. Blood gas analyses, compliance testing, and fluoroscopies were performed on postoperative days 1, 7, and 14. Lungs were removed for final analysis on day 14. RESULTS Perfusion decellularization of cadaveric lungs yielded acellular scaffolds with intact architecture and matrix composition. Alveolar volumes, number, and size were comparable in bioartificial and native lungs, as were gas exchange, vital capacity and compliance in vitro. After using improved graft preservation and postoperative weaning protocols, animals could be fully recovered, and bioartificial lung constructs provided oxygenation as long as 7 days at levels comparable to cadaveric lung transplants. Compliance, gas exchange, and radiographic appearance gradually declined over the subsequent 7 days owing to progressive graft consolidation and inflammation. CONCLUSIONS Perfusion decellularization of cadaveric lungs yields intact scaffolds that can be seeded with cells to generate bioartificial lung grafts. After orthotopic transplantation, grafts are perfused by the recipients circulation, ventilated through the recipients airway and provide gas exchange in vivo for 7 days.

A Novel Small-Molecule Inhibitor of Transforming Growth Factor β Type I Receptor Kinase (SM16) Inhibits Murine Mesothelioma Tumor Growth In vivo and Prevents Tumor Recurrence after Surgical Resection

Malignant mesothelioma is an aggressive and lethal pleural cancer that overexpresses transforming growth factor beta (TGFbeta). We investigated the efficacy of a novel small-molecule TGFbeta type I receptor (ALK5) kinase inhibitor, SM16, in the AB12 syngeneic model of malignant mesothelioma. SM16 inhibited TGFbeta signaling seen as decreased phosphorylated Smad2/3 levels in cultured AB12 cells (IC(50), approximately 200 nmol/L). SM16 penetrated tumor cells in vivo, suppressing tumor phosphorylated Smad2/3 levels for at least 3 h following treatment of tumor-bearing mice with a single i.p. bolus of 20 mg/kg SM16. The growth of established AB12 tumors was significantly inhibited by 5 mg/kg/d SM16 (P < 0.001) delivered via s.c. miniosmotic pumps over 28 days. The efficacy of SM16 was a result of a CD8+ antitumor response because (a) the antitumor effects were markedly diminished in severe combined immunodeficient mice and (b) CD8+ T cells isolated from spleens of mice treated with SM16 showed strong antitumor cytolytic effects whereas CD8+ T cells isolated from spleens of tumor-bearing mice treated with control vehicle showed minimal activity. Treatment of mice bearing large tumors with 5 mg/kg/d SM16 after debulking surgery reduced the extent of tumor recurrence from 80% to <20% (P < 0.05). SM16 was also highly effective in blocking and regressing tumors when given p.o. at doses of 0.45 or 0.65 g/kg in mouse chow. Thus, SM16 shows potent activity against established AB12 malignant mesothelioma tumors using an immune-mediated mechanism and can significantly prevent tumor recurrence after resection of bulky AB12 malignant mesothelioma tumors. These data suggest that ALK5 inhibitors, such as SM16, offer significant potential for the treatment of malignant mesothelioma and possibly other cancers.

Systemic blockade of transforming growth factor-beta signaling augments the efficacy of immunogene therapy.

Locally produced transforming growth factor-beta (TGF-beta) promotes tumor-induced immunosuppression and contributes to resistance to immunotherapy. This article explores the potential for increased efficacy when combining immunotherapies with TGF-beta suppression using the TGF-beta type I receptor kinase inhibitor SM16. Adenovirus expressing IFN-beta (Ad.IFN-beta) was injected intratumorally once in established s.c. AB12 (mesothelioma) and LKR (lung cancer) tumors or intratracheally in a Kras orthotopic lung tumor model. Mice bearing TC1 (lung cancer) tumors were vaccinated with two injections of adenovirus expressing human papillomavirus-E7 (HPV-E7; Ad.E7). SM16 was administered orally in formulated chow. Tumor growth was assessed and cytokine expression and cell populations were measured in tumors and spleens by real-time PCR and flow cytometry. SM16 potentiated the efficacy of both immunotherapies in each of the models and caused changes in the tumor microenvironment. The combination of SM16 and Ad.IFN-beta increased the number of intratumoral leukocytes (including macrophages, natural killer cells, and CD8(+) cells) and increased the percentage of T cells expressing the activation marker CD25. SM16 also augmented the antitumor effects of Ad.E7 in the TC1 flank tumor model. The combination did not increase HPV-E7 tetramer-positive CD8(+) T cells in the spleens but did induce a marked increase in the tumors. Tumors from SM16-treated mice showed increased mRNA and protein for immunostimulatory cytokines and chemokines, as well as endothelial adhesion molecules, suggesting a mechanism for the increased intratumoral leukocyte trafficking. Blockade of the TGF-beta signaling pathway augments the antitumor effects of Ad.IFN-beta immune-activating or Ad.E7 vaccination therapy. The addition of TGF-beta blocking agents in clinical trials of immunotherapies may increase efficacy.

Pulmonary Resection of Metastatic Sarcoma: Prognostic Factors Associated With Improved Outcomes

BACKGROUND There are few data to predict the benefit of pulmonary metastasectomy in patients with extrathoracic sarcoma. This study analyzes prognostic factors associated with improved outcomes. METHODS Between June 2002 and December 2008, 97 patients underwent pulmonary resection for metastatic sarcoma at Massachusetts General Hospital. Eight patients were excluded because of lack of follow-up data. Analysis was performed using Kaplan-Meier estimates of survival, log-rank test, and multivariate Cox model. RESULTS Overall 5-year survival for the cohort was 50.1%. Patients who had multiple operations for recurrent pulmonary metastases had better 5-year survival compared with patients who had a single operation (69 versus 41%; p = 0.017). Median disease- free survival (DFS) for the reoperation group was 12.9 months compared with 9.1 months for the single-operation group (p < 0.028). Patients with a disease-free interval (DFI) greater than 12 months from detection of primary sarcoma to pulmonary metastasectomy had improved survival compared with those whose DFI was less than 12 months (p < 0.0001). Patients with bilateral metastasectomy had lower 5-year survival compared with metastasectomy for unilateral disease (22% versus 68% ;p < 0.0001). Two or more metastases were associated with poorer outcome compared with a single metastasis (p = 0.0007). A positive resection margin portended worse survival compared with a negative resection margin (p = 0.004). Patients with lesions larger than 3 cm had decreased survival compared with patients with lesions smaller than 3 cm (p = 0.017) with no difference in median DFS. Histologic type, grade of tumor, and use of chemotherapy had no effect on survival. Multivariate analysis showed that patients with a DFI greater than 12 months (p = 0.001), single-sided metastasis (p = 0.001), negative margins (p = 0.002), and multiple operations (p = 0.018) had better survival. CONCLUSIONS Pulmonary metastasectomy for sarcoma can be associated with prolonged survival. Tumor resectability, DFI, number of metastases, and laterality are important factors in determining patient selection for curative surgical intervention. Repeated pulmonary metastasectomy in select patients may improve survival despite recurrent disease.

B-cell depletion using an anti-CD20 antibody augments antitumor immune responses and immunotherapy in nonhematopoetic murine tumor models.

The role played by B cells in cancer biology is complex and somewhat controversial. Previous studies using genetically engineered mice suggest that B cells may be immunosuppressive and inhibit tumor rejection. However, the effects of B-cell depletion employing an antibody in mice bearing solid tumors has not been tested owing to difficulties in making an effective antimouse CD20 antibody (similar to rituximab). Injection of a newly developed antimouse CD20 antibody was effective in depleting circulating B cells from blood and lymph nodes, although depletion was less complete in the spleen. B-cell depletion slowed the growth of new solid tumors (not expressing CD20) and retarded the growth of established tumors but did not induce tumor regression. However, when the antibody was combined with an active immunotherapy approach using an adenovirus vaccine expressing the human papilloma virus-E7 gene (Ad.E7) in mice bearing TC1 tumors (murine lung cancer cells expressing human papilloma virus-E7), we noted enhanced antitumor effects and increased numbers of tetramer+/CD8+ T cells within the spleens and activated CD8+ T cells within tumors. B-cell depletion using an anti-CD20 antibody was thus effective in retarding tumor growth in multiple solid tumor models and augmenting immunotherapy in a tumor vaccine model. These studies raise the possibility that B-cell depletion may be a useful adjunct in human immunotherapy trials.

CUL7 Is a Novel Antiapoptotic Oncogene

Using an expression cloning approach, we identify CUL7, a member of the cullin family, as a functional inhibitor of Myc-induced apoptosis. Deregulated expression of the Myc oncogene drives cellular proliferation yet also sensitizes cells to undergo p53-dependent and p53-independent apoptosis. Here, we report that CUL7 exerts its antiapoptotic function through p53. CUL7 binds directly to p53, and small interfering RNA-mediated knockdown of CUL7 results in the elevation of p53 protein levels. This antiapoptotic role of CUL7 enables this novel oncogene to cooperate with Myc to drive transformation. Deregulated ectopic expression of c-Myc and CUL7 promotes Rat1a cell growth in soft agar, and knockdown of CUL7 significantly blocks human neuroblastoma SHEP cell growth in an anchorage-independent manner. Furthermore, using public microarray data sets, we show that CUL7 mRNA is significantly overexpressed in non-small cell lung carcinoma and is associated with poor patient prognosis. We provide experimental evidence to show CUL7 is a new oncogene that cooperates with Myc in transformation by blocking Myc-induced apoptosis in a p53-dependent manner.

Factors in the Selection and Management of Chest Tubes After Pulmonary Lobectomy: Results of a National Survey of Thoracic Surgeons

BACKGROUND This study determined patterns of chest tube (CT) selection and management after open lobectomy and minimally invasive lobectomy by thoracic surgeons. METHODS Surveys were sent electronically to 5,175 thoracic surgeons, and 475 were completed. Responses, blinded so individuals could not be identified, were analyzed and compared according to surgeon characteristics (academic/private practice, years in practice, lobectomy volume, and geographic region). All indicated differences were statistically significant (p < 0.05 by χ(2) tests). RESULTS CT selection: Most surgeons prefer rigid tubes, and the size most commonly used was 28F. Most place 2 CTs after open lobectomy and 1 CT after minimally invasive lobectomy. Academic surgeons are more likely than private surgeons to use 1 tube after open lobectomy, but both prefer 1 tube after minimally invasive lobectomy. Younger surgeons and high-volume surgeons are more likely to use 1 CT than senior surgeons and low-volume surgeons after both open lobectomy and minimally invasive lobectomy. CT management: Academic and younger surgeons remove the CT sooner after open lobectomy. Younger and high-volume surgeons remove the CT with greater drainage amounts. All groups remove CTs sooner after minimally invasive lobectomy than after open lobectomy. Approximately half of surgeons get a daily chest roentgenogram. Younger and low-volume surgeons are most likely to discharge patients with Heimlich valves, although overall use was in less than 5% (49 of 475) of respondents. Most surgeons believe clinical experience rather than training or the literature determined their CT strategy. CONCLUSIONS This survey determined the difference in CT management among various groups of surgeons. Clinical experience was the most important factor in determining their CT strategy.

Minimally invasive approach for percutaneous CentriMag right ventricular assist device support using a single PROTEKDuo Cannula

BackgroundRight ventricular failure is a serious complication after left ventricular assist device placement.Case PresentationA 70-year-old male in decompensated heart failure with right ventricular failure after the placement of a left ventricular assist device. A single dual-lumen PROTEKDuo cannula was inserted percutaneously via the internal jugular vein to draw blood from the right atrium and return into the pulmonary artery using the CentriMag system, by passing the failing ventricle. The patient was successfully weaned from right ventricular assist device.ConclusionsIn comparison to two-cannula conventional procedures, this right ventrivular assist device system improves patient rehabilitation and minimizes blood loss and risk of infection, while shortening procedure time and improving clinical outcomes in right ventricular failure.

Intraoperative thermographic imaging to assess myocardial distribution of Del Nido cardioplegia

We describe the intraoperative non‐invasive use of an infrared (IR) camera to monitor Del Nido cardioplegia delivery in patients undergoing cardiac surgery. Thermal pictures were taken pre‐ and post‐cardioplegia and at timed points after arrest, and compared to readings from a transseptal temperature probe. There was good concordance between the transseptal probe and the IR camera temperature readings. This non‐invasive technique, which assesses cardioplegic distribution, may help to determine when additional doses of Del Nido cardioplegia are required during periods of cardioplegic arrest.

Unicentric Castleman’s disease presenting as a pulmonary mass: A diagnostic dilemma

Patient: Female, 16 Final Diagnosis: Castleman’s Disease Symptoms: Chest pain • cough non-productive Medication: — Clinical Procedure: — Specialty: Oncology Objective: Rare disease Background: Castleman’s disease, or angiofollicular lymphoid hyperplasia, is a rare disorder and can be easily misdiagnosed as lymphoma, neoplasm, or infection. The diagnosis is challenging due to the nonspecific signs and symptoms as well as the rarity of the disease. We present an unusual case of a young girl presenting with an enlarging pulmonary mass that was believed to be infectious in origin. Case Report: A 16-year-old Native American female from Arizona initially presented with occasional non-productive cough and chest pain. Imaging revealed a 3-cm left upper lobe lobulated mass. This mass was thought to be due to coccidioidomycosis and was treated with fluconazole. Follow-up imaging demonstrated growth of the mass to 4.8 cm. The patient underwent a left video-assisted thoracoscopic left upper lobectomy and mediastinal lymphadenectomy. Histopathological examination revealed Castleman’s disease. Conclusions: Pulmonary masses in young patients can be easily misdiagnosed as infections or cancer. We present the case of a 16-year-old female misdiagnosed as having a fungal infection of the lung, which was later revealed to be Castleman’s disease of the left upper lobe.