Mir Alireza Hoda

Hypoxia-Dependent Regulation of Nonphagocytic NADPH Oxidase Subunit NOX4 in the Pulmonary Vasculature

Nonphagocytic NADPH oxidases have recently been suggested to play a major role in the regulation of physiological and pathophysiological processes, in particular, hypertrophy, remodeling, and angiogenesis in the systemic circulation. Moreover, NADPH oxidases have been suggested to serve as oxygen sensors in the lung. Chronic hypoxia induces vascular remodeling with medial hypertrophy leading to the development of pulmonary hypertension. We screened lung tissue for the expression of NADPH oxidase subunits. NOX1, NOXA1, NOXO1, p22phox, p47phox, p40phox, p67phox, NOX2, and NOX4 were present in mouse lung tissue. Comparing mice maintained for 21 days under hypoxic (10% O2) or normoxic (21% O2) conditions, an upregulation exclusively of NOX4 mRNA was observed under hypoxia in homogenized lung tissue, concomitant with increased levels in microdissected pulmonary arterial vessels. In situ hybridization and immunohistological staining for NOX4 in mouse lungs revealed a localization of NOX4 mRNA and protein predominantly in the media of small pulmonary arteries, with increased labeling intensities after chronic exposure to hypoxia. In isolated pulmonary arterial smooth muscle cells (PASMCs), NOX4 was localized primarily to the perinuclear space and its expression levels were increased after exposure to hypoxia. Treatment of PASMCs with siRNA directed against NOX4 decreased NOX4 mRNA levels and reduced PASMC proliferation as well as generation of reactive oxygen species. In lungs from patients with idiopathic pulmonary arterial hypertension (IPAH), expression levels of NOX4, which was localized in the vessel media, were 2.5-fold upregulated. These results support an important role for NOX4 in the vascular remodeling associated with development of pulmonary hypertension.

Does Gastric Dilatation Limit the Success of Sleeve Gastrectomy as a Sole Operation for Morbid Obesity

Background: Sleeve gastrectomy as the sole bariatric operation has been reported for high-risk super-obese patients or as first-step followed by Roux-en-Y gastric bypass (RYGBP) or duodenal switch (DS) in super-super obese patients. The efficacy of laparoscopic sleeve gastrectomy (LSG) for morbidly obese patients with a BMI of <50 kg/m2 and the incidence of gastric dilatation following LSG have not yet been investigated. Methods: 23 patients (15 morbidly obese, 8 super-obese) were studied prospectively for weight loss following LSG. The incidence of sleeve dilatation was assessed by upper GI contrast studies in patients with a follow-up of >12 months. Results: Patients who underwent LSG achieved a mean excess weight loss (EWL) at 6 and 12 months postoperatively of 46% and 56%, respectively. No significant differences were observed in %EWL comparing obese and super-obese patients. At a mean follow-up of 20 months, dilatation of the gastric sleeve was found in 1 patient and weight regain after initial successful weight loss in 3 of the 23 patients. Conclusion: LSG has been highly effective for weight reduction for morbid obesity even as the sole bariatric operation. Gastric dilatation was found in only 1 patient in this short-term follow-up. Weight regain following LSG may require conversion to RYGBP or DS. Follow-up will be necessary to evaluate long-term results.

Encephalitis and GABAB receptor antibodies: Novel findings in a new case series of 20 patients

Objective: To report the clinical features of 20 newly diagnosed patients with GABAB receptor (GABABR) antibodies and determine the frequency of associated tumors and concurrent neuronal autoantibodies. Methods: Clinical data were retrospectively obtained and evaluated. Serum and CSF samples were examined for additional antibodies using methods previously reported. Results: Seventeen patients presented with seizures, memory loss, and confusion, compatible with limbic encephalitis (LE), one patient presented with ataxia, one patient presented with status epilepticus, and one patient presented with opsoclonus-myoclonus syndrome (OMS). Nineteen (95%) patients eventually developed LE during the course of the disease. Small-cell lung cancer (SCLC) was identified in 10 (50%) patients, all with LE. Treatment and outcome was available from 19 patients: 15 showed complete (n = 7) or partial (n = 8) neurologic improvement after steroids, IV immunoglobulins, or plasma exchange and oncologic treatment when indicated; 1 patient died of tumor progression shortly after the first cycle of immunotherapy, and 3 were not treated. Five patients with SCLC had additional onconeuronal antibodies (Ri, amphiphysin, or SOX1), and 2 without tumor had GAD65 and NMDAR antibodies, respectively. GABABR antibodies were not detected in serum of 116 patients with SCLC without neurologic symptoms. Conclusion: Our study confirms GABABR as an autoantigen of paraneoplastic and nonparaneoplastic LE and expands the phenotype of GABABR antibodies to ataxia, OMS, and status epilepticus. The long-term prognosis is dictated by the presence of a tumor. Recognition of syndromes associated with GABABR antibodies is important because they usually respond to treatment.

Pulmonary Vascular Reactivity and Prognosis in Patients With Chronic Thromboembolic Pulmonary Hypertension A Pilot Study

Background— Surgical pulmonary endarterectomy is the preferred treatment for chronic thromboembolic pulmonary hypertension. Persistent pulmonary hypertension after pulmonary endarterectomy has been recognized as a major determinant of poor outcome. We tested whether acute vasoreactivity identifies chronic thromboembolic pulmonary hypertension patients prone to develop persistent/recurrent pulmonary hypertension after pulmonary endarterectomy and whether the degree of acute vasoreactivity affects survival or freedom from lung transplantation. Methods and Results— Right-sided heart catheterization at baseline and after inhalation of 40 ppm nitric oxide for 20 minutes was performed in 103 patients (56.3±15.3 years old, 53 women). Reductions in mean pulmonary arterial pressure (&Dgr;mPAP; −8.8±12.6%; P<0.0001) and pulmonary vascular resistance (−16.1±18.1%; P<0.0001) and an increase in mixed venous saturation during inhaled nitric oxide (9.1±11.6%; P<0.0001) were observed. Sixty-two patients underwent pulmonary endarterectomy after a median of 49 days (25th and 75th percentiles: 24 and 123 days). Operated patients were followed up for a median of 70.9 months (25th and 75th percentiles: 14 and 97 months). Change in mPAP during inhaled NO was identified as a predictor of persistent/recurrent pulmonary hypertension after pulmonary endarterectomy. Patients experiencing a reduction in mPAP >10.4% with nitric oxide inhalation had a better postoperative outcome. A significant correlation was found between &Dgr;mPAP and immediate postoperative pulmonary vascular resistance (r=0.5, P<0.0001). Conclusions— A total of 80 (77.7%) of 103 patients demonstrated acute pulmonary vascular reactivity of some degree. A decrease in mPAP >10.4% under inhaled nitric oxide is a predictor of long-term survival and freedom from lung transplantation in adult patients with chronic thromboembolic pulmonary hypertension who are undergoing pulmonary endarterectomy.

The Noncanonical WNT Pathway Is Operative in Idiopathic Pulmonary Arterial Hypertension

Idiopathic pulmonary arterial hypertension (IPAH) is a fatal disease that comprises sustained vasoconstriction, enhanced proliferation of pulmonary vascular cells, and in situ thrombosis. The discovery of several contributing signaling pathways in recent years has resulted in an expanding array of novel therapies; however, IPAH remains a progressive disease with poor outcome in most instances. To identify new regulatory pathways of vascular remodeling in IPAH, we performed transcriptome-wide expression profiling of laser-microdissected pulmonary arterial resistance vessels derived from explanted IPAH and nontransplanted donor lung tissues. Statistical analysis of the data derived from six individuals in each group showed significant regulation of several mediators of the canonical and noncanonical WNT pathway. As to the noncanonical WNT pathway, the planar cell polarity (PCP) pathway, the ras homolog gene family member A (RHOA), and ras-related C3 botulinum toxin substrate-1 (RAC1) were strongly up-regulated. Real-time PCR of laser-microdissected pulmonary arteries confirmed these array results and showed in addition significant up-regulation of further PCP mediators wingless member 11 (WNT11), disheveled associated activator of morphogenesis-1 (DAAM1), disheveled (DSV), and RHO-kinase (ROCK). Immunohistochemical staining and semiquantitative expression analysis confirmed the markedly enhanced expression of the PCP mediators in the pulmonary resistance vessels, in particular in the endothelial layer in IPAH. Therefore we propose the PCP pathway to be critically involved in the regulation of vascular remodeling in IPAH.

High VEGFR-3-positive Circulating Lymphatic/Vascular Endothelial Progenitor Cell Level Is Associated with Poor Prognosis in Human Small Cell Lung Cancer

Purpose: The newly identified bone marrow–derived cell population, called lymphatic/vascular endothelial progenitor cells (LVEPC), has been shown to contribute to lymph capillary growth in experimental tumor systems. The clinical significance of these cells has not yet been investigated in a human malignancy. Our aim was to study whether peripheral blood circulating LVEPCs participate in the progression of human small cell lung cancer (SCLC). Experimental Design: A total of 88 patients with limited-stage SCLC and 32 tumor-free control subjects were included. Peripheral blood circulating LVEPC labeled with CD34 and vascular endothelial growth factor receptor-3 (VEGFR3) antibodies and the serum levels of the key lymphangiogenic molecule VEGF-C were measured by flow cytometry and ELISA, respectively. Results: CD34-positive/VEGFR3-positive LVEPC levels were significantly increased in patients (versus controls; P < 0.01), and there was also a significant relationship between LVEPC counts and lymph node metastasis (P < 0.01). High pretreatment circulating LVEPC numbers correlated with poor overall survival (P < 0.01). Although we observed significantly elevated VEGF-C concentrations in patients (versus controls; P < 0.01), there was no significant correlation between VEGF-C and LVEPC levels. Moreover, no significant differences in peripheral blood VEGF-C levels were seen between patients subgrouped by clinicopathologic variables including tumor and lymph node stages and survival. Conclusions: Peripheral blood levels of bone marrow–derived LVEPCs are significantly increased in patients with SCLC and correlate with lymphatic involvement and prognosis. This is the first study that shows evidence of increased numbers of circulating LVEPC in patients with a malignant tumor.

Current treatment paradigms of superior sulcus tumours.

Pancoast or superior pulmonary sulcus tumours are a rare subset of non-small-cell lung carcinomas (NSCLCs) which occur with an incidence of less than 5% of all lung cancers. Today, induction chemoradiation followed by surgical resection has become the established standard treatment approach for patients with sulcus superior tumours in the absence of other contraindications. This review focusses on the historical change of the treatment strategy, the evolution of surgical and multimodality management of this disease and the most recent published clinical outcome data of patients suffering from superior pulmonary sulcus carcinoma.

Subtype-specific KRAS mutations in advanced lung adenocarcinoma: A retrospective study of patients treated with platinum-based chemotherapy

BACKGROUND Platinum-based chemotherapy is the most common treatment in advanced-stage lung adenocarcinoma. Because the clinical significance of KRAS mutational status in this setting has not yet been clearly determined, a mutation subtype-specific analysis was performed in the so far largest cohort of Caucasian patients with KRAS mutant advanced-stage lung adenocarcinoma treated with platinum-based chemotherapy. METHODS 505 Caucasian stage III-IV lung adenocarcinoma patients with known amino acid substitution-specific KRAS mutational status and treated with platinum-based chemotherapy were included. The correlations of subtype-specific KRAS mutations with smoking status, progression-free and overall survival (PFS and OS, respectively) and therapeutic response were analysed. RESULTS Among 338 KRAS wild-type, 147 codon 12 mutant and 20 codon 13 mutant patients, there were no mutation-related significant differences in PFS or OS (P values were 0.534 and 0.917, respectively). Eastern Cooperative Oncology Group (ECOG) status and clinical stage were significant independent prognostic factors. KRAS mutation showed a significant correlation with smoking status (P=0.018). Importantly, however, G12V KRAS mutant patients were significantly more frequent among never-smokers than all other codon 12 KRAS mutant (G12x) subtypes (P=0.016). Furthermore, this subgroup tended to have a higher response rate (66% versus 47%; P=0.077). A modestly longer median PFS was also found in the G12V mutant cohort (233days; versus 175days in the G12x group; P=0.145). CONCLUSIONS While KRAS mutation status per se is neither prognostic nor predictive in stage III-IV lung adenocarcinoma, subtype-specific analysis may indeed identify clinically relevant subgroups of patients that may ultimately influence treatment decisions.

Distinct Epidemiology and Clinical Consequence of Classic Versus Rare EGFR Mutations in Lung Adenocarcinoma.

Introduction: Although classic sensitizing mutations of epidermal growth factor receptor (EGFR) are positive predictive markers for EGFR tyrosine kinase inhibitors (TKIs) in lung adenocarcinoma, there are rare EGFR mutations with unknown epidemiology and influence on prognosis and TKI response. Methods: Eight hundred and fourteen lung adenocarcinoma patients with KRAS and/or EGFR mutation analyses for TKI therapy indication were identified. Six hundred and forty-five patients were included in the epidemiological analysis. The clinical outcome was analyzed in 419 advanced-stage patients with follow-up data. Results: Four hundred and eighty (59%) KRAS/EGFR double wild-type, 216 (27%) KRAS mutant, 42 (5%) classic, 49 (6%) rare, and 27 (3%) synonymous EGFR mutant cases were identified. Twenty previously unpublished non-synonymous mutations were found. Rare EGFR mutations were significantly associated with smoking (vs. classic EGFR mutations; p = 0.0062). Classic EGFR mutations but not rare ones were independent predictors of increased overall survival (hazard ratios, 0.45; 95% confidence intervals, 0.25–0.82; p = 0.009). TKI therapy response rate of patients harboring classic EGFR mutations was significantly higher (vs. rare EGFR mutations; 71% vs. 37%; p = 0.039). Patients with classic or sensitizing rare (G719x and L861Q) EGFR mutations had significantly longer progression-free survival when compared with the remaining rare mutation cases (12 vs. 6.2 months; p = 0.048). Conclusions: The majority of rare EGFR mutations was associated with smoking, shorter overall survival, and decreased TKI response when compared with classic EGFR mutations. However, studies characterizing the TKI sensitizing effect of individual rare mutations are indispensable to prevent the exclusion of patients with sensitizing rare EGFR mutations who may benefit from anti-EGFR therapy.

Temsirolimus Inhibits Malignant Pleural Mesothelioma Growth In Vitro and In Vivo: Synergism with Chemotherapy

Introduction:Human malignant pleural mesothelioma (MPM) is an asbestos-related malignancy characterized by frequent resistance to chemotherapy and radiotherapy. Here, we investigated the feasibility of mammalian target of rapamycin (mTOR) inhibition by temsirolimus as an antimesothelioma strategy. Methods:Phosphorylation of mTOR (p-mTOR) was assessed by immunohistochemistry in MPM surgical specimens (n = 70). Activation of mTOR and impact of mTOR inhibition by temsirolimus was determined in MPM cell lines in vitro (n = 6) and in vivo as xenografts in severe combined immunodeficiency mice (n = 2) either as single agent or in combination with cisplatin. Results:Strong immunoreactivity for p-mTOR was predominantly detected in epitheloid and biphasic but not sarcomatoid MPM specimens while adjacent normal tissues remained widely unstained. Accordingly, all mesothelioma cell lines harbored activated mTOR, which was further confirmed by hyperphosphorylation of the downstream targets pS6K, S6, and 4EBP1. Temsirolimus potently blocked mTOR-mediated signals and exerted a cytostatic effect on mesothelioma cell lines in vitro cultured both as adherent monolayers and as nonadherent spheroids. Mesothelioma cells with intrinsic or acquired cisplatin resistance exhibited hypersensitivity against temsirolimus. Accordingly, cisplatin and temsirolimus exerted synergistic inhibition of the mTOR downstream signals and enhanced growth inhibition and/or apoptosis induction in mesothelioma cell lines. Finally, temsirolimus was highly active against MPM xenograft models in severe combined immunodeficiency mice both as a single agent and in combination with cisplatin. Conclusion:The mTOR inhibitor temsirolimus is active against mesothelioma in vitro and in vivo and synergizes with chemotherapy. These data suggest mTOR inhibition as a promising novel therapeutic strategy against MPM.