p16 Protein and gigaxonin are associated with the ubiquitination of NFκB in cisplatin-induced senescence of cancer cells

The molecular mechanism of p16-mediated senescence in cisplatin-treated cancer cells is not fully understood. Here we show that cisplatin treatment of head and neck cancer cells results in nuclear transport of p16 leading to a molecular modification of NFκB. Chromatin immunoprecipitation assays show that this modification is associated with the inhibition of NFκB interacting with its DNA binding sequences, leading to decreased expression of NFκB-transcribed proteins. LCMS proteomic analysis of LAP-TAP-purified proteins from HeLa cells containing a tetracycline-inducible GFP-S peptide-NFκB expression system identified gigaxonin, an ubiquitin E3 ligase adaptor, as an NFκB-interacting protein. Immunoblotting and siRNA studies confirmed the NFκB-gigaxonin interaction and the dependence of this binding on p16-NFκB binding. Using gel shift assays, we have confirmed p16-NFκB and gigaxonin-NFκB interactions. Furthermore, we have observed increased NFκB ubiquitination with cisplatin treatment that is abolished in the absence of p16 and gigaxonin expression. Analysis of 103 primary tumors has shown that increased nuclear p16 expression correlates with enhanced survival of head and neck cancer patients (p < 0.0000542), indicating the importance of nuclear p16 expression in prognosis. Finally, p16 expression is associated with reduced cytokine expression and the presence of human papilloma virus in chemoradiation-sensitive basaloid tumors. However, the absence of p16 expression is associated with enhanced cytokine expression and the absence of human papilloma virus in aggressive tumors. These results clearly demonstrate that nuclear p16 and gigaxonin play an important role in chemosensitivity of head and neck cancers through ubiquitination of NFκB.

Abstract 2449: Identifying therapy responsive and resistant LKB1 mutant non-small cell lung tumor populations

The LKB1/STK11 tumor suppressor is mutationally inactivated in ∼30% of sporadic non-small cell lung cancers (NSCLC), and to date there are no agents targeting loss of LKB1 in lung cancer. LKB1 is the major upstream kinase activating the energy sensing kinase AMPK under conditions of low intracellular ATP. In cells defective for LKB1, metabolic stress is not appropriately sensed and energy homeostasis is not efficiently restored, providing an Achilles heel to target in tumors with this genetic lesion. Importantly, LKB1-deficient (LKB1-/-) NSCLC cells are unable to restore energy homeostasis in response to biguanide-induced energy stress and preferentially undergo apoptosis. As targeted therapy for LKB1 mutant tumors are needed, we explored the use of the metabolic stress agent phenformin as an anti- cancer drug to target the LKB1-/- NSCLC. Phenformin is a biguanide that has historically used to treat metabolic disease and we demonstrated that it potently induced apoptosis in LKB1-/- lung tumors and significantly prolonged survival in genetically engineered mouse models (GEMMs) of lung cancer in mice bearing tumors with mutated Kras and Lkb1 genes but not mice with compound mutations in Kras and p53. Our pre-clinical studies suggest phenformin may be used as a cancer metabolism-based prevention agent or therapeutic to selectively target LKB1-/- pulmonary epithelial cells and tumors. However, phenformin as a single agent therapy was not curative, highlighting the need to find additional therapies to prevent or target LKB1-/- lung tumors in combination with phenformin. We have previously shown LKB1 loss leads to mTORC1 hyperactivation therefore we explored the combinatorial use of phenformin with the mTOR kinase inhibitor MLN128. We tested phenformin and MLN128 together on our human and mouse models of lung cancer and demonstrated the two drugs cooperated together to enhance apoptosis and reduce proliferation. KrasG12D driven, Lkb1-/- mice develop both adenocarcinoma (ADC) and squamous cell carcinomas (SQCC). We performed 18FDG-PET and CT guided pre-clinical studies assessing phenformin + MLN128 as a combinatorial therapy in vivo using our Lkb1-/- GEMMs of NSCLC. We discovered that lung ADC were highly responsive to the combination therapy while the SQCC lung tumor populations appear highly resistant. These findings carry important clincal relevance as currently there are limited options for patients with LKB1-mutant tumors. Here we define the hypersensitivity of LKB1-/- lung ADC tumors to metabolic stress and mTOR inhibition while in parallel identifying a therapy resistant SQCC lung tumor population. These results suggest phenformin in combination with mTOR kinase inhibitors may find clinical utility to treat LKB1 mutant lung ADC.

Citation Format: Evan Abt, Milica Momcilovic, Atsuko Seki, Robert McMickle, David Stout, Michael C. Fishbein, David B. Shackelford. Identifying therapy responsive and resistant LKB1 mutant non-small cell lung tumor populations. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2449. doi:10.1158/1538-7445.AM2014-2449

Abstract 932: The impact of e-cigarette exposure on pulmonary epithelium gene expression and transformation

Lung cancer is the leading cause of cancer-related mortality in the United States. Despite a strong correlation between cigarette smoking and the onset of lung cancer, the prevalence of smoking still remains high. The electronic cigarette (ECIG) is designed to deliver nicotine without combusting tobacco. Since nicotine is widely considered the addictive component in tobacco with limited ability to initiate cancer, ECIGs have been advertised to be a safer alternative to tobacco cigarettes (TCIGs). However, the potential health risks and carcinogenicity of ECIGs have not previously been evaluated. In this study, we assess the impact of in vitro ECIG exposure on the carcinogenic potential of immortalized human bronchial epithelial cells on a background of silenced p53 and activated KRAS (H-P53/KRAS). This model is utilized because p53 and KRAS mutations are often observed in the airway of current and former smokers at risk for lung cancer. Our preliminary results suggest that ECIG-induced alterations may be dependent upon the mutational landscape of the airway cells being exposed. In anchorage independent growth assays, the in vitro correlate of malignant transformation, we found enhanced colony growth in the H-P53/KRAS cells following a 10-day treatment with the high nicotine ECIG-conditioned media compared to the untreated and low nicotine treatment groups. We next assessed the effect of ECIG exposure on cell invasion using three-dimensional air-liquid interface (ALI) models. H-P53KRAS cells exhibited invasion-associated morphological changes following a 10-day treatment with the high nicotine conditioned media, including increased proliferation, diminished cell-cell cohesion and the appearance of cells percolating out of and breaching the modified basement membrane. Finally, gene expression profiles show 263 differentially expressed genes following exposure to high nicotine ECIG-conditioned media for 96hrs. The ECIG-conditioned media induced a gene expression pattern similar to TCIG-conditioned media and whole cigarette smoke exposure in the H-P53/KRAS cells. We will next compare the ECIG-induced gene expression signature to carcinogenicity-related gene signatures established in previous and ongoing clinical investigations and test ECIG-altered candidate genes for their ability to drive the malignant transformation of airway epithelial cells. These studies will determine the impact of ECIG exposure on lung carcinogenicity and provide needed scientific guidance to the FDA regarding the physiologic effects of ECIGs. These studies were supported by funding from the following: NIH/NCI #U01CA152751 (SMD, TCW), NCI #U01CA152751-S1 (SMD, TCW, SJP), NCI #U01CA152751-AS (SMD, KK), NCI #T32-CA009120-36 (SMD, SJP, PCP), NIH/NHLBI #T32HL072752 (SMD, EL), University of California Tobacco-Related Disease Research Program (TRDRP) #18FT-0060 (TCW), TRDRP #20KT-0055 (TCW), Lung Cancer SPORE (P50CA70907, JDM, JEL)

Citation Format: Stacy J. Park, Tonya C. Walser, Catalina Perdomo, Teresa Wang, Long-Sheng Hong, Paul C. Pagano, Elvira L. Liclican, Kostyantyn Krysan, Jill E. Larsen, Michael C. Fishbein, John D. Minna, Marc E. Lenburg, Avrum Spira, Steven M. Dubinett. The impact of e-cigarette exposure on pulmonary epithelium gene expression and transformation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 932. doi:10.1158/1538-7445.AM2014-932

The 2013 International Society for Heart and Lung Transplantation Working Formulation for the standardization of nomenclature in the pathologic diagnosis of antibody-mediated rejection in heart transplantation

During the last 25 years, antibody-mediated rejection of the cardiac allograft has evolved from a relatively obscure concept to a recognized clinical complication in the management of heart transplant patients. Herein we report the consensus findings from a series of meetings held between 2010-2012 to develop a Working Formulation for the pathologic diagnosis, grading, and reporting of cardiac antibody-mediated rejection. The diagnostic criteria for its morphologic and immunopathologic components are enumerated, illustrated, and described in detail. Numerous challenges and unresolved clinical, immunologic, and pathologic questions remain to which a Working Formulation may facilitate answers.

Estimating sympathetic tone by recording subcutaneous nerve activity in ambulatory dogs

INTRODUCTION

We tested the hypothesis that subcutaneous nerve activity (SCNA) of the thorax correlates with the stellate ganglion nerve activity (SGNA) and can be used to estimate the sympathetic tone.

METHODS AND RESULTS

We implanted radio transmitters in 11 ambulatory dogs to record left SGNA, left thoracic vagal nerve activity (VNA), and left thoracic SCNA, including 3 with simultaneous video monitoring and nerve recording. Two additional dogs were studied under general anesthesia with apamin injected into the right stellate ganglion while the right SGNA and the right SCNA were recorded. There was a significant positive correlation between integrated SGNA (iSGNA) and integrated SCNA (iSCNA) in the first 7 ambulatory dogs, with correlation coefficient of 0.70 (95% confidence interval [CI] 0.61-0.84, P < 0.05 for each dog). Tachycardia episodes (heart rate exceeding 150 bpm for ≥3 seconds) were invariably preceded by SGNA and SCNA. There was circadian variation of both SCNA and SGNA. Crosstalk was ruled out because SGNA, VNA, and SCNA bursts had different timing and activation patterns. In an eighth dog, closely spaced bipolar subcutaneous electrodes also recorded SCNA, but with reduced signal to noise ratio. Video monitoring in additional 3 dogs showed that movement was not a cause of high frequency SCNA. The right SGNA correlated strongly with right SCNA and heart rate in 2 anesthetized dogs after apamin injection into the right stellate ganglion.

CONCLUSIONS

SCNA recorded by bipolar subcutaneous electrodes correlates with the SGNA and can be used to estimate the sympathetic tone.

Posterolateral hypertrophic cardiomyopathy: a rare, but clinically significant variant of hypertrophic cardiomyopathy

Posterolateral hypertrophic cardiomyopathy (HCM) is a rare variant of HCM. Segmental HCM is seen in 12% of cases of HCM. Among the patterns of segmental HCM, posterolateral HCM is the least common type. Our case of an 18-year old male documents this unusual type of cardiomyopathy. In this form of HCM, left ventricular thickness and the extent of hypertrophy might be underestimated by 2-dimensional echocardiography. This case illustrates the echocardiographic and pathologic features of posterolateral HCM.

Sarcoidosis-associated pulmonary hypertension and lung transplantation for sarcoidosis

Pulmonary hypertension (PH) is a significant complication of sarcoidosis, occurring in approximately 6 to > 20% of cases, and markedly increases mortality among these patients. The clinician should exercise a high index of suspicion for sarcoidosis-associated PH (SAPH) given the nonspecific symptomatology and the limitations of echocardiography in this patient population. The pathophysiology of PH in sarcoidosis is complex and multifactorial. Importantly, there are inherent differences in the pathogenesis of SAPH compared with idiopathic pulmonary arterial hypertension, making the optimal management of SAPH controversial. In this article, we review the epidemiology, diagnosis, prognosis, and treatment considerations for SAPH. Lung transplantation (LT) is a viable therapeutic option for sarcoid patients with severe pulmonary fibrocystic sarcoidosis or SAPH refractory to medical therapy. We discuss the role for LT in patients with sarcoidosis, review the global experience with LT in this population, and discuss indications and contraindications to LT.

Pathogenesis of arrhythmias in a model of CKD

Patients with CKD have an increased risk of cardiovascular mortality from arrhythmias and sudden cardiac death. We used a rat model of CKD (Cy/+) to study potential mechanisms of increased ventricular arrhythmias. Rats with CKD showed normal ejection fraction but hypertrophic myocardium. Premature ventricular complexes occurred more frequently in CKD rats than normal rats (42% versus 11%, P=0.18). By optical mapping techniques, action potential duration (APD) at 80% of repolarization was longer in CKD rats (78±4ms) than normal rats (63±3 ms, P<0.05) at a 200-ms pacing cycle length. Calcium transient (CaT) duration was comparable. Pacing cycle length thresholds to induce CaT alternans or APD alternans were longer in CKD rats than normal rats (100±7 versus 80±3 ms and 93±6 versus 76±4 ms for CaT and APD alternans, respectively, P<0.05), suggesting increased vulnerability to ventricular arrhythmia. Ventricular fibrillation was induced in 9 of 12 CKD rats and 2 of 9 normal rats (P<0.05); early afterdepolarization occurred in two CKD rats but not normal rats. The mRNA levels of TGF-β, microRNA-21, and sodium calcium-exchanger type 1 were upregulated, whereas the levels of microRNA-29, L-type calcium channel, sarco/endoplasmic reticulum calcium-ATPase type 2a, Kv1.4, and Kv4.3 were downregulated in CKD rats. Cardiac fibrosis was mild and not different between groups. We conclude that cardiac ion channel and calcium handling are abnormal in CKD rats, leading to increased vulnerability to early afterdepolarization, triggered activity, and ventricular arrhythmias.

Role of the autonomic nervous system in atrial fibrillation: pathophysiology and therapy

Autonomic nervous system activation can induce significant and heterogeneous changes of atrial electrophysiology and induce atrial tachyarrhythmias, including atrial tachycardia and atrial fibrillation (AF). The importance of the autonomic nervous system in atrial arrhythmogenesis is also supported by circadian variation in the incidence of symptomatic AF in humans. Methods that reduce autonomic innervation or outflow have been shown to reduce the incidence of spontaneous or induced atrial arrhythmias, suggesting that neuromodulation may be helpful in controlling AF. In this review, we focus on the relationship between the autonomic nervous system and the pathophysiology of AF and the potential benefit and limitations of neuromodulation in the management of this arrhythmia. We conclude that autonomic nerve activity plays an important role in the initiation and maintenance of AF, and modulating autonomic nerve function may contribute to AF control. Potential therapeutic applications include ganglionated plexus ablation, renal sympathetic denervation, cervical vagal nerve stimulation, baroreflex stimulation, cutaneous stimulation, novel drug approaches, and biological therapies. Although the role of the autonomic nervous system has long been recognized, new science and new technologies promise exciting prospects for the future.

Sympathetic nerve fibers in human cervical and thoracic vagus nerves

BACKGROUND

Vagus nerve stimulation (VNS) therapy has been used for chronic heart failure and is believed to improve imbalance of autonomic control by increasing parasympathetic activity. Although it is known that there is neural communication between the VN and the cervical sympathetic trunk, there are few data regarding the quantity and/or distribution of the sympathetic components within the vagus nerve (VN).

OBJECTIVE

To examine the sympathetic components within the human VN and correlate them with the presence of cardiac and neurologic diseases.

METHODS

We performed immunohistochemistry on 31 human cervical and thoracic VNs (total 104 VNs) from autopsies and reviewed the patients' records. We correlated the quantity of sympathetic nerve fibers within the VNs with cardiovascular and neurologic disease states.

RESULTS

All 104 VNs contain tyrosine hydroxylase (TH)-positive (sympathetic) nerve fibers; the mean TH-positive areas were 5.47% in the right cervical VN, 3.97% in the left cervical VN, 5.11% in the right thoracic VN, and 4.20% in the left thoracic VN. The distribution of TH-positive nerve fibers varied from case to case: central, peripheral, or scattered throughout nerve bundles. No statistically significant differences in nerve morphology were seen between diseases in which VNS is considered effective (depression and chronic heart failure) and other cardiovascular diseases or neurodegenerative disease.

CONCLUSION

Human VNs contain sympathetic nerve fibers. The sympathetic component within the VN could play a role in physiologic effects reported with VNS. The recognition of sympathetic nerve fibers in the VNs may lead to better understanding of the therapeutic mechanisms of VNS.

Interstitial lung disease in patients with hepatopulmonary syndrome: a case series and new observations

Hepatopulmonary syndrome (HPS) is characterized by impaired oxygenation due to pulmonary vascular dilatation in patients with end-stage liver disease. At our center, we identified 29 patients who were listed for liver transplantation (LT) with a model for end-stage liver disease exception for HPS between 2001 and 2012. Five of these patients were found to have concurrent interstitial lung disease (ILD). The chest high-resolution computed-tomography demonstrated ground-glass opacities and subpleural reticulation, most consistent with nonspecific interstitial pneumonia (NSIP). All four of our patients who underwent LT experienced prolonged hypoxemia postoperatively, with one surgery-related death. However, the three surviving patients had eventual resolution of their hypoxemia with no evidence of ILD progression. In conclusion, we report a high prevalence of ILD, most consistent with NSIP, among patients with HPS. Although there may be increased perioperative risks, the finding of ILD in patients with HPS should not be considered an absolute contraindication to LT.

FGF23 protein expression in coronary arteries is associated with impaired kidney function

BACKGROUND

Fibroblast growth factor 23 (FGF23) levels are elevated in chronic kidney disease (CKD) and elevated values have been associated with both heart disease and mortality. Recent studies show that FGF23, a protein synthesized by osteocytes, is also present in calcified atherosclerotic plaques and may be induced by heart disease. Whether vascular expression of FGF23 is associated with progressive CKD, however, remains unknown. Therefore, the relationship between kidney function, vascular calcification and FGF23 expression was evaluated in patients with heart disease.

METHODS

Immunohistochemistry for FGF23 was performed in coronary arteries of all patients undergoing heart transplantation at UCLA between February 2008 and 2010. Immunohistochemical staining for Klotho, DMP1, FGFR1, and FGFR3; calcium deposition; and RNA expression of Klotho and DMP1 were assessed in a subset of eight samples.

RESULTS

FGF23 was detected by immunohistochemistry in 56% of the coronary artery specimens. Vascular FGF23 expression correlated with declining kidney function, as evidenced by reduced creatinine clearance. FGFR1 and FGFR3 were detected throughout the vascular tissue and in calcified plaques. Calcium deposition, Klotho expression and DMP1 expression correlated with FGF23 immunoreactivity.

CONCLUSIONS

The findings suggest that the Klotho-FGF23-FGFR system is active in coronary arteries and its upregulation correlates with impaired renal function and matrix calcium deposition.

CXCR3 ligands are associated with the continuum of diffuse alveolar damage to chronic lung allograft dysfunction

RATIONALE

After lung transplantation, insults to the allograft generally result in one of four histopathologic patterns of injury: (1) acute rejection, (2) lymphocytic bronchiolitis, (3) organizing pneumonia, and (4) diffuse alveolar damage (DAD). We hypothesized that DAD, the most severe form of acute lung injury, would lead to the highest risk of chronic lung allograft dysfunction (CLAD) and that a type I immune response would mediate this process.

OBJECTIVES

Determine whether DAD is associated with CLAD and explore the potential role of CXCR3/ligand biology.

METHODS

Transbronchial biopsies from all lung transplant recipients were reviewed. The association between the four injury patterns and subsequent outcomes were evaluated using proportional hazards models with time-dependent covariates. Bronchoalveolar lavage (BAL) concentrations of the CXCR3 ligands (CXCL9/MIG, CXCL10/IP10, and CXCL11/ITAC) were compared between allograft injury patterns and "healthy" biopsies using linear mixed-effects models. The effect of these chemokine alterations on CLAD risk was assessed using Cox models with serial BAL measurements as time-dependent covariates.

MEASUREMENTS AND MAIN RESULTS

There were 1,585 biopsies from 441 recipients with 62 episodes of DAD. An episode of DAD was associated with increased risk of CLAD (hazard ratio, 3.0; 95% confidence interval, 1.9-4.7) and death (hazard ratio, 2.3; 95% confidence interval, 1.7-3.0). There were marked elevations in BAL CXCR3 ligand concentrations during DAD. Furthermore, prolonged elevation of these chemokines in serial BAL fluid measurements predicted the development of CLAD.

CONCLUSIONS

DAD is associated with marked increases in the risk of CLAD and death after lung transplantation. This association may be mediated in part by an aberrant type I immune response involving CXCR3/ligands.

Autonomic nerve activity and blood pressure in ambulatory dogs

BACKGROUND

The relationship between cardiac autonomic nerve activity and blood pressure (BP) changes in ambulatory dogs is unclear.

OBJECTIVE

The purpose of this study was to test the hypotheses that simultaneous termination of stellate ganglion nerve activity (SGNA) and vagal nerve activity (VNA) predisposes to spontaneous orthostatic hypotension and that specific β₂-adrenoceptor blockade prevents the hypotensive episodes.

METHODS

We used a radiotransmitter to record SGNA, VNA, and BP in eight ambulatory dogs. Video imaging was used to document postural changes.

RESULTS

Of these eight dogs, five showed simultaneous sympathovagal discharges in which the minute-by-minute integrated SGNA correlated with integrated VNA in a linear pattern (group 1). In these dogs, abrupt termination of simultaneous SGNA-VNA at the time of postural changes (as documented by video imaging) was followed by abrupt (>20 mm Hg over four beats) drops in BP. Dogs without simultaneous on/off firing (group 2) did not have drastic drops in pressure. ICI-118,551 (ICI, a specific β₂-blocker) infused at 3 µg/kg/h for 7 days significantly increased BP from 126 mm Hg (95% confidence interval 118-133) to 133 mm Hg (95% confidence interval 125-141; P = .0001). The duration of hypotension (mean systolic BP <100 mm Hg) during baseline accounted for 7.1% of the recording. The percentage was reduced by ICI to 1.3% (P = .01).

CONCLUSION

Abrupt simultaneous termination of SGNA-VNA was observed at the time of orthostatic hypotension in ambulatory dogs. Selective β₂-adrenoceptor blockade increased BP and reduced the duration of hypotension in this model.

A novel molecular pathway for Snail-dependent, SPARC-mediated invasion in non-small cell lung cancer pathogenesis

Definition of the molecular pathogenesis of lung cancer allows investigators an enhanced understanding of the natural history of the disease, thus fostering development of new prevention strategies. In addition to regulating epithelial-to-mesenchymal transition (EMT), the transcription factor Snail exerts global effects on gene expression. Our recent studies reveal that Snail is upregulated in non-small cell lung cancer (NSCLC), is associated with poor prognosis, and promotes tumor progression in vivo. Herein, we demonstrate that overexpression of Snail leads to the upregulation of secreted protein, acidic and rich in cysteine (SPARC) in models of premalignancy and established disease, as well as in lung carcinoma tissues in situ. Snail overexpression leads to increased SPARC-dependent invasion in vitro, indicating that SPARC may play a role in lung cancer progression. Bioinformatic analysis implicates transforming growth factor beta (TGF-β), extracellular signal-regulated kinase (ERK)1/2, and miR-29b as potential intermediaries in Snail-mediated upregulation of SPARC. Both the TGF-β1 ligand and TGF-β receptor 2 (TGF-βR2) are upregulated following Snail overexpression. Treatment of human bronchial epithelial cell (HBEC) lines with TGF-β1 and inhibition of TGF-β1 mRNA expression modulates SPARC expression. Inhibition of MAP-ERK kinase (MEK) phosphorylation downregulates SPARC. MiR-29b is downregulated in Snail-overexpressing cell lines, whereas overexpression of miR-29b inhibits SPARC expression. In addition, miR-29b is upregulated following ERK inhibition, suggesting a Snail-dependent pathway by which Snail activation of TGF-β and ERK signaling results in downregulation of miR-29b and subsequent upregulation of SPARC. Our discovery of pathways responsible for Snail-induced SPARC expression contributes to the definition of NSCLC pathogenesis.

Characterization of Anatomic Ventricular Tachycardia Isthmus Pathology After Surgical Repair of Tetralogy of Fallot

Background—

Although catheter ablation has been used to target the critical isthmuses for re-entrant monomorphic ventricular tachycardia in tetralogy of Fallot, the anatomy and histology of these regions have not been fully characterized. Autopsy hearts with tetralogy of Fallot were evaluated to clarify the pathological substrate.

Methods and Results—

Twenty-seven hearts with the diagnosis of tetralogy of Fallot were examined. Anatomically defined isthmuses included (1A) ventriculotomy-to-tricuspid annulus, (1B) ventriculotomy-to-ventricular septal defect patch, (2) ventriculotomy-to-pulmonary annulus, (3) pulmonary annulus-to-ventricular septal defect patch, and (4) ventricular septal defect patch-to-tricuspid annulus. Length and wall thickness were measured for all specimens, and light microscopy was performed for those surviving surgery. For subjects ≥5 years at death, isthmuses 1A and 1B were present in 88%, isthmus 2 in 25%, isthmus 3 in 94%, and isthmus 4 in 13%. Isthmus 1A had the greatest dimensions (mean length, 3.9±1.08; thickness, 1.5±0.3 cm), isthmus 1B intermediate dimensions (mean length, 2.4±0.8; thickness, 1.1±0.4 cm), and isthmuses 2, 3, and 4 the smallest dimensions (mean length, 1.5±0.5, 1.4±0.8, and 0.6±0.4 cm; thickness, 0.5±0.2, 0.6±0.2, and 0.3±0.04 cm, respectively). Histological examination (n=7) revealed increased fibrosis in anatomic isthmuses relative to nonisthmus controls.

Conclusions—

Consistencies in isthmus dimensions and histology are found among patients with repaired tetralogy of Fallot. Isthmus 1A is associated with the largest morphological dimensions, whereas the nearby newly described isthmus 1B is significantly smaller. Of isthmuses with the smallest dimensions, isthmus 3 is the most common.

Pulmonary hypertension complicating connective tissue disease

Pulmonary hypertension (PH) may complicate connective tissue disease (CTD), particularly systemic sclerosis (SSc, scleroderma), and markedly increases mortality. More than 70% of cases of PH complicating CTD occur in SSc, which is the major focus of this article. Pulmonary complications (i.e., interstitial lung disease [ILD] and PH) are the leading causes of scleroderma-related deaths. "Isolated" PH (i.e., without ILD) complicates SSc in 7.5 to 20% of cases; secondary PH may also occur in patients with SSc-associated ILD. Several clinical markers and specific autoantibody profiles have been associated with PH in SSc. The role of PH-specific therapy is controversial, as prognosis and responsiveness to therapy are worse in SSc-associated PH compared with idiopathic pulmonary arterial hypertension. We discuss medical therapies for CTD-associated PH and the role of lung transplantation for patients failing medical therapy.

The CD44(high) tumorigenic subsets in lung cancer biospecimens are enriched for low miR-34a expression

Cellular heterogeneity is an integral part of cancer development and progression. Progression can be associated with emergence of cells that exhibit high phenotypic plasticity (including “de-differentiation” to primitive developmental states), and aggressive behavioral properties (including high tumorigenic potentials). We observed that many biomarkers that are used to identify Cancer Stem Cells (CSC) can label cell subsets in an advanced clinical stage of lung cancer (malignant pleural effusions, or MPE). Thus, CSC-biomarkers may be useful for live sorting functionally distinct cell subsets from individual tumors, which may enable investigators to hone in on the molecular basis for functional heterogeneity. We demonstrate that the CD44^hi (CD44-high) cancer cell subsets display higher clonal, colony forming potential than CD44^lo cells (n = 3) and are also tumorigenic (n = 2/2) when transplanted in mouse xenograft model. The CD44^hi subsets express different levels of embryonal (de-differentiation) markers or chromatin regulators. In archived lung cancer tissues, ALDH markers co-localize more with CD44 in squamous cell carcinoma (n = 5/7) than Adeno Carcinoma (n = 1/12). MPE cancer cells and a lung cancer cell line (NCI-H-2122) exhibit chromosomal abnormalities and 1p36 deletion (n = 3/3). Since miR-34a maps to the 1p36 deletion site, low miR-34a expression levels were detected in these cells. The colony forming efficiency of CD44^hi cells, characteristic property of CSC, can be inhibited by mir-34a replacement in these samples. In addition the highly tumorigenic CD44^hi cells are enriched for cells in the G2 phase of cell cycle.

Elevated neutrophil gelatinase-associated lipocalin contributes to erlotinib resistance in non-small cell lung cancer

PURPOSE

The EGFR tyrosine kinase inhibitors (TKIs) demonstrate efficacy in NSCLC patients whose tumors harbor activating EGFR mutations. However, patients who initially respond to EGFR TKI treatment invariably develop resistance to the drugs. Known mechanisms account for approximately 70% of native and acquired EGFR TKI resistance. In the current study we investigated a novel mechanism of NSCLC resistance to erlotinib.

EXPERIMENTAL DESIGN

The mechanisms of acquired erlotinib resistance were evaluated by microarray analysis in thirteen NSCLC cell lines and in vivo in mice. Correlations between plasma neutrophil gelatinase associated lipocalin (NGAL) levels, erlotinib response and the EGFR mutational status were assessed in advanced stage NSCLC patients treated with erlotinib.

RESULTS

In 5 of 13 NSCLC cell lines NGAL was significantly upregulated. NGAL knockdown in erlotinib-resistant cells increased erlotinib sensitivity in vitro and in vivo. NGAL overexpression in erlotinib-sensitive cells augmented apoptosis resistance. This was mediated by NGAL-dependent modulation of the pro-apoptotic protein Bim levels. Evaluation of the plasma NGAL levels in NSCLC patients that received erlotinib revealed that patients with lower baseline NGAL demonstrated a better erlotinib response. Compared to patients with wild type EGFR, patients with activating EGFR mutations had lower plasma NGAL at baseline and weeks 4 and 8.

CONCLUSIONS

Our studies uncover a novel mechanism of NGAL-mediated modulation of Bim levels in NSCLC that might contribute to TKI resistance in lung cancer patients. These findings provide the rationale for the further investigations of the utility of NGAL as a potential therapeutic target or diagnostic biomarker.

DNA viral infections complicating lung transplantation

DNA viruses with potential to cause complications after lung transplantation include the human Herpesviridae family consisting of cytomegalovirus (CMV), herpes simplex virus 1 and 2 (HSV-1, -2), varicella-zoster virus (VZV), human herpesvirus 6, 7, and 8 (HHV-6, -7, -8), and Epstein-Barr virus (EBV); the Polyomaviridae family consisting of BK virus and JC virus; and the Adenoviridae family consisting of more than 50 adenovirus subtypes. This is a diverse group of viruses with equally diverse immediate and long-term impacts on allograft function and clinical outcomes following lung transplantation. This article discusses the individual pathogens, their epidemiology and clinical manifestations, as well as treatment and preventive strategies in this era of antiviral treatment regimens.

LKB1 inactivation dictates therapeutic response of non-small cell lung cancer to the metabolism drug phenformin

The LKB1 (also called STK11) tumor suppressor is mutationally inactivated in ∼20% of non-small cell lung cancers (NSCLC). LKB1 is the major upstream kinase activating the energy-sensing kinase AMPK, making LKB1-deficient cells unable to appropriately sense metabolic stress. We tested the therapeutic potential of metabolic drugs in NSCLC and identified phenformin, a mitochondrial inhibitor and analog of the diabetes therapeutic metformin, as selectively inducing apoptosis in LKB1-deficient NSCLC cells. Therapeutic trials in Kras-dependent mouse models of NSCLC revealed that tumors with Kras and Lkb1 mutations, but not those with Kras and p53 mutations, showed selective response to phenformin as a single agent, resulting in prolonged survival. This study suggests phenformin as a cancer metabolism-based therapeutic to selectively target LKB1-deficient tumors.

Blockade of p-selectin is sufficient to reduce MHC I antibody-elicited monocyte recruitment in vitro and in vivo

Donor-specific HLA antibodies significantly lower allograft survival, but as yet there are no satisfactory therapies for prevention of antibody-mediated rejection. Intracapillary macrophage infiltration is a hallmark of antibody-mediated rejection, and macrophages are important in both acute and chronic rejection. The purpose of this study was to investigate the Fc-independent effect of HLA I antibodies on endothelial cell activation, leading to monocyte recruitment. We used an in vitro model to assess monocyte binding to endothelial cells in response to HLA I antibodies. We confirmed our results in a mouse model of antibody-mediated rejection, in which B6.RAG1(-/-) recipients of BALB/c cardiac allografts were passively transferred with donor-specific MHC I antibodies. Our findings demonstrate that HLA I antibodies rapidly increase intracellular calcium and endothelial presentation of P-selectin, which supports monocyte binding. In the experimental model, donor-specific MHC I antibodies significantly increased macrophage accumulation in the allograft. Concurrent administration of rPSGL-1-Ig abolished antibody-induced monocyte infiltration in the allograft, but had little effect on antibody-induced endothelial injury. Our data suggest that antagonism of P-selectin may ameliorate accumulation of macrophages in the allograft during antibody-mediated rejection.

Low-level vagus nerve stimulation upregulates small conductance calcium-activated potassium channels in the stellate ganglion

BACKGROUND

Small conductance calcium-activated potassium (SK) channels are responsible for afterhyperpolarization that suppresses nerve discharges.

OBJECTIVES

To test the hypothesis that low-level vagus nerve stimulation (LL-VNS) leads to the upregulation of SK2 proteins in the left stellate ganglion.

METHODS

Six dogs (group 1) underwent 1-week LL-VNS of the left cervical vagus nerve. Five normal dogs (group 2) were used as controls. SK2 protein levels were examined by using Western blotting. The ratio between SK2 and glyceraldehydes-3-phosphate-dehydrogenase levels was used as an arbitrary unit (AU).

RESULTS

We found higher SK2 expression in group 1 (0.124 ± 0.049 AU) than in group 2 (0.085 ± 0.031 AU; P<.05). Immunostaining showed that the density of nerve structures stained with SK2 antibody was also higher in group 1 (11,546 ± 7,271 μm(2)/mm(2)) than in group 2 (5321 ± 3164 μm(2)/mm(2); P<.05). There were significantly more ganglion cells without immunoreactivity to tyrosine hydroxylase (TH) in group 1 (11.4%±2.3%) than in group 2 (4.9% ± 0.7%; P<.05). The TH-negative ganglion cells mostly stained positive for choline acetyltransferase (95.9% ± 2.8% in group 1 and 86.1% ± 4.4% in group 2; P = .10). Immunofluorescence confocal microscopy revealed a significant decrease in the SK2 staining in the cytosol but an increase in the SK2 staining on the membrane of the ganglion cells in group 1 compared to group 2.

CONCLUSIONS

Left LL-VNS results in the upregulation of SK2 proteins, increased SK2 protein expression in the cell membrane, and increased TH-negative (mostly choline acetyltransferase-positive) ganglion cells in the left stellate ganglion. These changes may underlie the antiarrhythmic efficacy of LL-VNS in ambulatory dogs.

Interaction between Pseudomonas and CXC chemokines increases risk of bronchiolitis obliterans syndrome and death in lung transplantation

RATIONALE

Pseudomonas aeruginosa is the most commonly isolated gram-negative bacterium after lung transplantation and has been shown to up-regulate glutamic acid-leucine-arginine-positive (ELR(+)) CXC chemokines associated with bronchiolitis obliterans syndrome (BOS), but the effect of pseudomonas on BOS and death has not been well defined.

OBJECTIVES

To determine if the influence of pseudomonas isolation and ELR(+) CXC chemokines on the subsequent development of BOS and the occurrence of death is time dependent.

METHODS

A three-state model was developed to assess the likelihood of transitioning from lung transplant (state 1) to BOS (state 2), from transplant (state 1) to death (state 3), and from BOS (state 2) to death (state 3). This Cox semi-Markovian approach determines state survival rates and cause-specific hazards for movement from one state to another.

MEASUREMENTS AND MAIN RESULTS

The likelihood of transition from transplant to BOS was increased by acute rejection, CXCL5, and the interaction between pseudomonas and CXCL1. The pseudomonas effect in this transition was due to infection rather than colonization. Movement from transplant to death was facilitated by pseudomonas infection and single lung transplant. Transition from BOS to death was affected by the length of time in state 1 and by the interactions between any pseudomonas isolation and CXCL5 and aspergillus, either independently or in combination.

CONCLUSIONS

Our model demonstrates that common post-transplantation events drive movement from one post-transplantation state to another and influence outcomes differently depending upon when after transplantation they occur. Pseudomonas and the ELR(+) CXC chemokines may interact to negatively influence lung transplant outcomes.

Radiofrequency ablation of lung tumors: imaging features of the postablation zone

Radiofrequency ablation (RFA) is used to treat pulmonary malignancies. Although preliminary results are suggestive of a survival benefit, local progression rates are appreciable. Because a patient can undergo repeat treatment if recurrence is detected early, reliable post-RFA imaging follow-up is critical. The purpose of this article is to describe (a) an algorithm for post-RFA imaging surveillance; (b) the computed tomographic (CT) appearance, size, enhancement, and positron emission tomographic (PET) metabolic activity of the ablation zone; and (c) CT, PET, and dual-modality imaging with PET and CT (PET/CT) features suggestive of partial ablation or tumor recurrence and progression. CT is routinely used for post-RFA follow-up. PET and PET/CT have emerged as auxiliary follow-up techniques. CT with nodule densitometry may be used to supplement standard CT. Post-RFA follow-up was divided into three phases: early (immediately after to 1 week after RFA), intermediate (>1 week to 2 months), and late (>2 months). CT and PET imaging features suggestive of residual or recurrent disease include (a) increasing contrast material uptake in the ablation zone (>180 seconds on dynamic images), nodular enhancement measuring more than 10 mm, any central enhancement greater than 15 HU, and enhancement greater than baseline anytime after ablation; (b) growth of the RFA zone after 3 months (compared with baseline) and definitely after 6 months, peripheral nodular growth and change from ground-glass opacity to solid opacity, regional or distant lymph node enlargement, and new intrathoracic or extrathoracic disease; and (c) increased metabolic activity beyond 2 months, residual activity centrally or at the ablated tumor, and development of nodular activity.

Sympathetic nerve fibers and ganglia in canine cervical vagus nerves: localization and quantitation

BACKGROUND

Cervical vagal nerve (CVN) stimulation may improve left ventricular ejection fraction in patients with heart failure.

OBJECTIVES

To test the hypothesis that sympathetic structures are present in the CVN and to describe the location and quantitate these sympathetic components of the CVN.

METHODS

We performed immunohistochemical studies of the CVN from 11 normal dogs and simultaneously recorded stellate ganglion nerve activity, left thoracic vagal nerve activity, and subcutaneous electrocardiogram in 2 additional dogs.

RESULTS

A total of 28 individual nerve bundles were present in the CVNs of the first 11 dogs, with an average of 1.87±1.06 per dog. All CVNs contain tyrosine hydroxylase-positive (sympathetic) nerves, with a total cross-sectional area of 0.97±0.38 mm(2). The sympathetic nerves were nonmyelinated, typically located at the periphery of the nerve bundles and occupied 0.03%-2.80% of the CVN cross-sectional area. Cholineacetyltransferase-positive nerve fibers occupied 12.90%-42.86% of the CVN cross-sectional areas. Ten of 11 CVNs showed tyrosine hydroxylase and cholineacetyltransferase colocalization. In 2 dogs with nerve recordings, we documented heart rate acceleration during spontaneous vagal nerve activity in the absence of stellate ganglion nerve activity.

CONCLUSIONS

Sympathetic nerve fibers are invariably present in the CVNs of normal dogs and occupy in average up to 2.8% of the cross-sectional area. Because sympathetic nerve fibers are present in the periphery of the CVNs, they may be susceptible to activation by electrical stimulation. Spontaneous activation of the sympathetic component of the vagal nerve may accelerate the heart rate.

Pulmonary alveolar proteinosis

Pulmonary alveolar proteinosis (PAP) is a rare disorder characterized by the accumulation of surfactant lipids and protein in the alveolar spaces, with resultant impairment in gas exchange. The clinical course can be variable, ranging from spontaneous resolution to respiratory failure and death. PAP in all forms is caused by excessive accumulation of surfactant within the alveolar spaces. Autoimmune PAP accounts for the vast majority of cases in humans and is caused by autoantibodies to granulocyte-macrophage colony-stimulating factor (GM-CSF), which results in impaired catabolism and clearance of surfactant lipids and proteins. Inherited or congenital forms of PAP are exceptionally rare and caused by mutations of genes encoding for surfactant proteins. Secondary forms of PAP are associated with diverse clinical disorders and are caused by reduced alveolar macrophage numbers or function with resultant reduced pulmonary clearance of surfactant. PAP is characterized by progressive exertional dyspnea and nonproductive cough with hypoxemia. Bilateral infiltrates are typically present on chest radiograph, and high-resolution computed tomography reveals diffuse ground-glass opacities and airspace consolidation with interlobular septal thickening in a characteristic "crazy paving" pattern. Although surgical lung biopsy will provide a definitive diagnosis, a combination of typical clinical and imaging features with periodic acid-Schiff (PAS)-positive material on bronchoalveolar lavage and transbronchial biopsies is usually sufficient. The standard of care for treatment of PAP remains whole lung lavage, but treatment is not required in all patients. Autoimmune PAP has also been successfully treated with GM-CSF, both inhaled and systemic, but the optimal dose, duration, and route of administration of GM-CSF have not been elucidated.

Obliterative (constrictive) bronchiolitis

Obliterative bronchiolitis (OB) (formerly termed bronchiolitis obliterans), is a rare fibrotic disorder involving terminal and respiratory bronchioles. The term constrictive bronchiolitis is synonymous with OB. Clinically, OB is characterized by progressive (often fatal) airflow obstruction, the absence of parenchymal infiltrates on chest radiographs, a mosaic pattern of perfusion on high-resolution computed tomographic scan, poor responsiveness to therapy, and high mortality rates. Most cases of OB occur in the context of a specific risk factor. Currently, most cases of OB occur in lung transplant recipients with chronic allograft rejection or hematopoietic stem cell transplant (HSCT) recipients with graft versus host disease (GVHD). Other causes of OB include connective tissue disease (CTD) (particularly rheumatoid arthritis); lower respiratory tract infections; inhalation injury; exposure or inhalation of toxic fumes, metals, dusts, particulate matter, or pollutants; occupational exposures; drug reactions; consumption of uncooked leaves of Sauropus androgynus; chronic hypersensitivity pneumonia; diffuse neuroendocrine cell hyperplasia; miscellaneous. When no cause is identified, the term cryptogenic obliterative bronchiolitis is used. This review discusses the salient clinical, radiographic, and histological features of OB and presents a management approach.

Extracardiac neural remodeling in humans with cardiomyopathy

BACKGROUND

Intramyocardial nerve sprouting after myocardial infarction is associated with ventricular arrhythmias. Whether human stellate ganglia remodel in association with cardiac pathology is unknown. The purpose of this study was to determine whether cardiac pathology is associated with remodeling of the stellate ganglia in humans.

METHODS AND RESULTS

Left stellate ganglia were collected from patients undergoing sympathetic denervation for intractable ventricular arrhythmias and from cadavers, along with intact hearts. Clinical data on patients and cadaveric subjects were reviewed. We classified ganglia from normal, scarred, and nonischemic cardiomyopathic hearts without scar as NL (n=3), SCAR (n=24), and NICM (n=7), respectively. Within left stellate ganglia, neuronal size, density, fibrosis, synaptic density, and nerve sprouting were determined. Nerve density and sprouting were also quantified in cadaveric hearts. Mean neuronal size in normal, scarred, and nonischemic cardiomyopathic hearts without scar groups were 320 ± 4 μm(2), 372 ± 10 μm(2), and 435 ± 10 μm(2) (P=0.002), respectively. No significant differences in neuronal density and fibrosis were present between the groups. Synaptic density in ganglia from SCAR and NICM groups were 57.8 ± 11.2 μm(2)/mm(2) (P=0.084) and 44.5 ± 7.9 μm(2)/mm(2) (P=0.039), respectively, compared with the normal group, 17.8 ± 7 μm(2)/mm(2) (overall P=0.162). There were no significant differences in left stellate ganglia nerve sprouting or myocardial nerve density between the groups.

CONCLUSIONS

Neuronal hypertrophy within left stellate ganglia is associated with chronic cardiomyopathy in humans. Ganglionic and myocardial nerve sprouting and nerve density were not significantly different. These changes may be related to increased cardiac sympathetic signaling and ventricular arrhythmias. Further studies are needed to determine the electrophysiological consequences of extracardiac neuronal remodeling in humans.

A fluorescence lifetime imaging classification method to investigate the collagen to lipid ratio in fibrous caps of atherosclerotic plaque

BACKGROUND AND OBJECTIVE

This study describes a novel fluorescence lifetime imaging (FLIM) classification method to determine the ratio of collagen to lipid content in the fibrous cap of atherosclerotic plaques. Additionally, an analytical process to assess risk of plaque rupture based on this ratio is proposed. Collagen to lipid ratio has been shown to be an important parameter to evaluate structural integrity of the fibrous cap. FLIM and other time-resolved fluorescence techniques have recently been applied to the study of atherosclerosis based on the ability to assess biochemical composition.

STUDY DESIGN/MATERIALS AND METHODS

Autofluorescence of specimens retrieved during carotid endarterectomy procedures was measured through three optical filters, F377: 377/50 nm, F460: 460/66 nm, and F510: 510/84 nm (center wavelength/bandwidth). A Laguerre deconvolution technique was used for the evaluation of fluorescence decay dynamics. The resulting decay parameters (average fluorescence lifetime and 4 Laguerre coefficients at each of the recorded bandwidths) were used for sample characterization. Linear discriminant analysis (LDA) was used to classify each image into collagen or lipid-rich regions based on these parameters. Ultimately, a risk-level was assigned based on the ratio of collagen to lipid on the surface of the fibrous cap.

RESULTS

FLIM images were acquired in 18 carotid plaque specimens at 43 locations. Classification of collagen and lipid-rich regions within the fibrous cap was performed with sensitivity and specificity of 80% and 82%, respectively.

CONCLUSIONS

Results from this study show that an LDA method of classifying regions of FLIM images of carotid plaque into collagen and lipid-rich regions is capable of being automated and used to rate the risk of plaque rupture based on autofluorescence decay dynamics and without the need for fluorescence intensity or contrast agents.

Na,K-ATPase is a target of cigarette smoke and reduced expression predicts poor patient outcome of smokers with lung cancer

Diminished Na,K-ATPase expression has been reported in several carcinomas and has been linked to tumor progression. However, few studies have determined whether Na,K-ATPase function and expression are altered in lung malignancies. Because cigarette smoke (CS) is a major factor underlying lung carcinogenesis and progression, we investigated whether CS affects Na,K-ATPase activity and expression in lung cell lines. Cells exposed to CS in vitro showed a reduction of Na,K-ATPase activity. We detected the presence of reactive oxygen species (ROS) in cells exposed to CS before Na,K-ATPase inhibition, and neutralization of ROS restored Na,K-ATPase activity. We further determined whether Na,K-ATPase expression correlated with increasing grades of lung adenocarcinoma and survival of patients with smoking history. Immunohistochemical analysis of lung adenocarcinoma tissues revealed reduced Na,K-ATPase expression with increasing tumor grade. Using tissue microarray containing lung adenocarcinomas of patients with known smoking status, we found that high expression of Na,K-ATPase correlated with better survival. For the first time, these data demonstrate that CS is associated with loss of Na,K-ATPase function and expression in lung carcinogenesis, which might contribute to disease progression.

Neural control of ventricular rate in ambulatory dogs with pacing-induced sustained atrial fibrillation

BACKGROUND

We hypothesize that inferior vena cava-inferior atrial ganglionated plexus nerve activity (IVC-IAGPNA) is responsible for ventricular rate (VR) control during atrial fibrillation (AF) in ambulatory dogs.

METHODS AND RESULTS

We recorded bilateral cervical vagal nerve activity (VNA) and IVC-IAGPNA during baseline sinus rhythm and during pacing-induced sustained AF in 6 ambulatory dogs. Integrated nerve activities and average VR were measured every 10 seconds over 24 hours. Left VNA was associated with VR reduction during AF in 5 dogs (from 211 bpm [95% CI, 186-233] to 178 bpm [95% CI, 145-210]; P<0.001) and right VNA in 1 dog (from 208 bpm [95% CI, 197-223] to 181 bpm [95% CI, 163-200]; P<0.01). There were good correlations between IVC-IAGPNA and left VNA in the former 5 dogs and between IVC-IAGPNA and right VNA in the last dog. IVC-IAGPNA was associated with VR reduction in all dogs studied. Right VNA was associated with baseline sinus rate reduction from 105 bpm (95% CI, 95-116) to 77 bpm (95% CI, 64-91; P<0.01) in 4 dogs, whereas left VNA was associated with sinus rate reduction from 111 bpm (95% CI, 90-1250) to 81 bpm (95% CI, 67-103; P<0.01) in 2 dogs.

CONCLUSIONS

IVC-IAGPNA is invariably associated with VR reduction during AF. In comparison, right or left VNA was associated with VR reduction only when it coactivates with the IVC-IAGPNA. The vagal nerve that controls VR during AF may be different from that which controls sinus rhythm.

Electroanatomic remodeling of the left stellate ganglion after myocardial infarction

OBJECTIVES

The purpose of this study was to evaluate the changes of left stellate ganglionic nerve activity (SGNA) and left thoracic vagal nerve activity (VNA) after acute myocardial infarction (MI).

BACKGROUND

Whether MI results in remodeling of extracardiac nerve activity remains unclear.

METHODS

We implanted radiotransmitters to record the SGNA, VNA, and electrocardiogram in 9 ambulatory dogs. After baseline monitoring, MI was created by 1-h balloon occlusion of the coronary arteries. The dogs were then continuously monitored for 2 months. Both stellate ganglia were stained for growth-associated protein 43 and synaptophysin. The stellate ganglia from 5 normal dogs were used as control.

RESULTS

MI increased 24-h integrated SGNA from 7.44 ± 7.19 Ln(Vs)/day at baseline to 8.09 ± 7.75 Ln(Vs)/day after the MI (p < 0.05). The 24-h integrated VNA before and after the MI was 5.29 ± 5.04 Ln(Vs)/day and 5.58 ± 5.15 Ln(Vs)/day, respectively (p < 0.05). A significant 24-h circadian variation was noted for the SGNA (p < 0.05) but not the VNA. The SGNA/VNA ratio also showed significant circadian variation. The nerve densities from the left SG were 63,218 ± 34,719 μm(2)/mm(2) and 20,623 ± 4,926 μm(2)/mm(2) for growth-associated protein 43 (p < 0.05) and were 32,116 ± 8,190 μm(2)/mm(2)and 16,326 ± 4,679 μm(2)/mm(2) for synaptophysin (p < 0.05) in MI and control groups, respectively. The right SG also showed increased nerve density after MI (p < 0.05).

CONCLUSIONS

MI results in persistent increase in the synaptic density of bilateral stellate ganglia and is associated with increased SGNA and VNA. There is a circadian variation of the SGNA/VNA ratio. These data indicate significant remodeling of the extracardiac autonomic nerve activity and structures after MI.

Abstract 5355: Immunohistochemical variations in the expression of cancer stem cell and macrophage markers in primary and recurrent oral squamous cell carcinomas

Head and Neck Squamous Cell carcinoma (HNSCC) is the fifth most common malignancy worldwide. Oropharyngeal squamous cell carcinoma (OSCC) is the most common subtype and the sixth most common cancer in the US, with 8,000-10,000 deaths/year. Despite the best available treatment options of surgery, radiation and chemotherapy, the five year survival rate is approximately 50%, indicating recurrence is a common phenomenon. Preliminary studies with HNSCC cell lines have indicated higher expression of cancer stem cell markers such as CD44 in the aggressive tumor cell lines. It has been shown that cancer stem cells play an important role in the development and maintenance of tumor cells and in distant metastases. Thus, the current study was undertaken to determine whether cancer stem cell markers can be detected in primary and recurrent OSCC samples. In addition, since immune response cells such as macrophages may also play an important role in disease progression, we analyzed the distribution of macrophages in primary and recurrent tumors. Immunohistochemical analysis was performed on tumor samples of patients with OSCC. Five samples from patients with primary tumors and five samples from patients with recurrent tumors were analyzed for CD 44, ALDH, and Bmi-1, cancer stem cell markers of HNSCC. In addition, all samples were stained with a monoclonal antibody, CD68, a marker for the detection of tumor-associated macrophages. In the primary tumor group, CD 44 and Bmi-1 stained diffusely throughout the specimens (&gt;90% staining), especially at the periphery of the lesions. ALDH stained strongly (&gt;90%) and diffusely in two of the primary samples, and scattered staining (3-5% of tumor cells) was seen in the other three primary samples. CD 68 stained mainly around tumor clusters but not between individual tumor cells. The recurrent tumors also showed a strong staining of CD 44 within the tumor, especially at the periphery. In contrast, staining of ALDH and Bmi-1 was relatively weak. Additionally, in contrast to the primary tumors, CD 68 staining was more diffuse, and especially strong between tumor cells, suggesting a migration of tumor-associated macrophages into the tumor. These features reflect the transitory and tumor-microenvironment dependent expression of biomarkers that mediate the aggressive tumor cell properties. In this context, the data suggest that infiltrating macrophages may be playing an important role in mediating both tumor recurrence, and the transition towards aggressive tumor cell phenotypes. Further studies will be required to determine the role of macrophage mediated modulation of aggressive properties (secreted cytokines versus cell-cell interactions) of oral squamous cell tumors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5355. doi:1538-7445.AM2012-5355

Canonical Wnt/β-catenin signaling in epicardial fibrosis of failed pediatric heart allografts with diastolic dysfunction

BACKGROUND

Failed pediatric heart allografts with diastolic dysfunction exhibit severe epicardial fibrosis. The molecular mechanism underlying this process is poorly understood. Canonical Wnt/β-catenin signaling plays an important role in epithelial-mesenchymal transition and is implicated in fibrosing diseases. In this study, we tested the hypothesis that canonical Wnt/β-catenin signaling is activated in epicardial fibrosis of end-stage dysfunctional pediatric allografts.

METHODS

Fourteen explanted heart grafts of 12 patients who had undergone 14 heart transplantations were used for immunohistochemical staining of β-catenin and its nuclear binding partners, T-cell factor/lymphoid enhancer factor family transcriptional factors. Fourteen age-matched native hearts from patients who had undergone first heart transplantation without evidence of epicardial fibrosis were used as controls.

RESULTS AND CONCLUSIONS

Epicardial fibroblasts from explanted allografts demonstrated nuclear accumulation of β-catenin. These cells also showed nuclear positivity for T-cell factor 4. No T-cell factor 3 expression was present in the epicardium. T-cell factor 1 and lymphoid enhancer factor 1 were observed in lymphocytes, but not in other cell types of the epicardium. These findings suggest an association between canonical Wnt/beta-catenin signaling and epicardial fibrosis of failed pediatric heart allografts. Should activation of this pathway be shown to be causal to epicardial fibrosis in this setting, then inhibition of this pathway may help to prevent this devastating process.

Enhanced sensitivity of aged fibrotic hearts to angiotensin II- and hypokalemia-induced early afterdepolarization-mediated ventricular arrhythmias

Unlike young hearts, aged hearts are highly susceptible to early afterdepolarization (EAD)-mediated ventricular fibrillation (VF). This differential may result from age-related structural remodeling (fibrosis) or electrical remodeling of ventricular myocytes or both. We used optical mapping and microelectrode recordings in Langendorff-perfused hearts and patch-clamp recordings in isolated ventricular myocytes from aged (24-26 mo) and young (3-4 mo) rats to assess susceptibility to EADs and VF during either oxidative stress with ANG II (2 μM) or ionic stress with hypokalemia (2.7 mM). ANG II caused EAD-mediated VF in 16 of 19 aged hearts (83%) after 32 ± 7 min but in 0 of 9 young hearts (0%). ANG II-mediated VF was suppressed with KN-93 (Ca(2+)/calmodulin-dependent kinase inhibitor) and the reducing agent N-acetylcysteine. Hypokalemia caused EAD-mediated VF in 11 of 11 aged hearts (100%) after 7.4 ± 0.4 min. In 14 young hearts, however, VF did not occur in 6 hearts (43%) or was delayed in onset (31 ± 22 min, P < 0.05) in 8 hearts (57%). In patch-clamped myocytes, ANG II and hypokalemia (n = 6) induced EADs and triggered activity in both age groups (P = not significant) at a cycle length of >0.5 s. When myocytes of either age group were coupled to a virtual fibroblast using the dynamic patch-clamp technique, EADs arose in both groups at a cycle length of <0.5 s. Aged ventricles had significantly greater fibrosis and reduced connexin43 gap junction density compared with young hearts. The lack of differential age-related sensitivity at the single cell level in EAD susceptibility indicates that increased ventricular fibrosis in the aged heart plays a key role in increasing vulnerability to VF induced by oxidative and ionic stress.

Triggered firing and atrial fibrillation in transgenic mice with selective atrial fibrosis induced by overexpression of TGF-β1

BACKGROUND

Calcium transient triggered firing (CTTF) is induced by large intracellular calcium (Ca(i)) transient and short action potential duration (APD). We hypothesized that CTTF underlies the mechanisms of early afterdepolarization (EAD) and spontaneous recurrent atrial fibrillation (AF) in transgenic (Tx) mice with overexpression of transforming growth factor β1 (TGF-β1).

METHODS AND RESULTS

MHC-TGFcys(33)ser Tx mice develop atrial fibrosis because of elevated levels of TGF-β1. We studied membrane potential and Ca(i)transients of isolated superfused atria from Tx and wild-type (Wt) littermates. Short APD and persistently elevated Ca(i) transients promoted spontaneous repetitive EADs, triggered activity and spontaneous AF after cessation of burst pacing in Tx but not Wt atria (39% vs. 0%, P=0.008). We were able to map optically 4 episodes of spontaneous AF re-initiation. All first and second beats of spontaneous AF originated from the right atrium (4/4, 100%), which is more severely fibrotic than the left atrium. Ryanodine and thapsigargin inhibited spontaneous re-initiation of AF in all 7 Tx atria tested. Western blotting showed no significant changes of calsequestrin or sarco/endoplasmic reticulum Ca(2+)-ATPase 2a.

CONCLUSIONS

Spontaneous AF may occur in the Tx atrium because of CTTF, characterized by APD shortening, prolonged Ca(i) transient, EAD and triggered activity. Inhibition of Ca(2+) release from the sarcoplasmic reticulum suppressed spontaneous AF. Our results indicate that CTTF is an important arrhythmogenic mechanism in TGF-β1 Tx atria.

Interleukin-1β is crucial for the induction of coronary artery inflammation in a mouse model of Kawasaki disease

BACKGROUND

Kawasaki disease (KD) is the most common cause of acute vasculitis and acquired cardiac disease in US children. Untreated, children may develop coronary artery aneurysms, myocardial infarction, and sudden death as a result of the illness. Up to a third of KD patients fail to respond to intravenous immunoglobulin, the standard therapy, and alternative treatments are being investigated. Genetic studies have indicated a possible role for interleukin (IL)-1β in KD. We therefore explored the role of IL-1β in a murine model of KD.

METHODS AND RESULTS

Using an established mouse model of KD that involves injection of Lactobacillus casei cell wall extract (LCWE), we investigated the role of IL-1β and caspase-1 (activated by the inflammasome and required for IL-1β maturation) in coronary arteritis and evaluated the efficacy of IL-1 receptor antagonist as a potential treatment. LCWE-induced IL-1β maturation and secretion were dependent on the NLRP3 inflammasome in macrophages. Both caspase-1-deficient and IL-1 receptor-deficient mice were protected from LCWE-induced coronary lesions. Injection of recombinant IL-1β into caspase-1-deficient mice restored the ability of LCWE to cause coronary lesions in response to LCWE. Furthermore, daily injections of the IL-1 receptor antagonist prevented LCWE-mediated coronary lesions up to 3 days after LCWE injection.

CONCLUSIONS

Our results strongly suggest that caspase-1 and IL-1β play critical roles in the development of coronary lesions in this KD mouse model, blocked by IL-1 receptor antagonist. Therefore, anti-IL-1β treatment strategies may constitute an effective, more targeted treatment of KD to prevent coronary lesions.

CXCR3 chemokine ligands during respiratory viral infections predict lung allograft dysfunction

Community-acquired respiratory viruses (CARV) can accelerate the development of lung allograft dysfunction, but the immunologic mechanisms are poorly understood. The chemokine receptor CXCR3 and its chemokine ligands, CXCL9, CXCL10 and CXCL11 have roles in the immune response to viruses and in the pathogenesis of bronchiolitis obliterans syndrome, the predominant manifestation of chronic lung allograft rejection. We explored the impact of CARV infection on CXCR3/ligand biology and explored the use of CXCR3 chemokines as biomarkers for subsequent lung allograft dysfunction. Seventeen lung transplant recipients with CARV infection had bronchoalveolar lavage fluid (BALF) available for analysis. For comparison, we included 34 BALF specimens (2 for each CARV case) that were negative for infection and collected at a duration posttransplant similar to a CARV case. The concentration of each CXCR3 chemokine was increased during CARV infection. Among CARV infected patients, a high BALF concentration of either CXCL10 or CXCL11 was predictive of a greater decline in forced expiratory volume in 1 s, 6 months later. CXCR3 chemokine concentrations provide prognostic information and this may have important implications for the development of novel treatment strategies to modify outcomes after CARV infection.

Snail as a novel marker for regional metastasis in head and neck squamous cell carcinoma

OBJECTIVE

Previous studies have shown Snail expression integral to the epithelial-mesenchymal transition during tumor progression. However, its behavior in clinical head and neck squamous cell carcinomas (HNSCCs) is yet undefined. We therefore sought to (1) investigate clinical and histopathologic characteristics of Snail-positive HNSCC and (2) understand the link between Snail and other commonly used HNSCC tumor markers.

STUDY DESIGN

A retrospective case-control study was conducted.

SETTING

This study was conducted in a large-scale academic center.

STUDY SUBJECTS

Of 51 consecutive HNSCC, 42 surgical resections were included.

METHODS

Two separate pathologists performed standard histopathologic reviews along with immunohistochemistries (Snail, E-cadherin, p16, epidermal growth factor receptor [EGFR]) and in situ hybridization (human papilloma virus [HPV]). Medical review for all cases was performed.

RESULTS

Twenty-two (52%) of 42 cases stained 4+ Snail (>75% staining). The remaining 20 cases were considered negative. Snail was strongly inversely related to E-cadherin expression (ρ = -0.69, P < .001), but statistically independent from HPV, p16, or EGFR expression. Snail(+) tumors were equally represented from each anatomic subsite. Snail(+) tumors were strongly associated with poor differentiation (P < .001) and basaloid classification (P = .004). Snail(+) tumors were also strongly associated with lymphovascular invasion (P = .02), but not perineural invasion. Ultimately, 11 (50%) of 22 of Snail(+) tumors demonstrated positive nodal metastasis and 11 (79%) of 14 node-positive cases were Snail(+) (P = .02).

CONCLUSION

This pilot study provides promising evidence of Snail' role as a molecular prognostic marker for HNSCC. Snail positivity is significantly predictive of poorly differentiated, lymphovascular invasive, as well as regionally metastatic tumors. Because Snail positivity appears independent of HPV, p16, and EGFR expression, Snail may prove to improve upon these markers' predictive limitations.

2011 consensus statement on endomyocardial biopsy from the Association for European Cardiovascular Pathology and the Society for Cardiovascular Pathology

The Association for European Cardiovascular Pathology and the Society for Cardiovascular Pathology have produced this position paper concerning the current role of endomyocardial biopsy (EMB) for the diagnosis of cardiac diseases and its contribution to patient management, focusing on pathological issues, with these aims: • Determining appropriate EMB use in the context of current diagnostic strategies for cardiac diseases and providing recommendations for its rational utilization • Providing standard criteria and guidance for appropriate tissue triage and pathological analysis • Promoting a team approach to EMB use, integrating the competences of pathologists, clinicians, and imagers.