Cell viability of fibroblasts to pifenidone and sirolimus: a future concept for drug eluting stents

Tracheobronchial stents: an expanding prospect

The first dedicated tracheobronchial silicone stent was designed by the French pulmonologist Jean-Paul Dumon. The most common indications for stenting are to minimise extrinsic airway compression from mass effect, maintain airway patency due to intrinsic obstruction or treat significant nonmalignant airway narrowing or fistulae. Silicone stents require rigid bronchoscopy for insertion; however, they are more readily repositioned and removed compared with metallic stents. Metallic stents demonstrate luminal narrowing when loads are applied to their ends, therefore stents should either be reinforced at the ends or exceed the area of stenosis by a minimum of 5 mm. Nitinol, a nickel-titanium metal alloy, is currently the preferred material used for airway stents. Airway stenting provides effective palliation for patients with severe symptomatic obstruction. Drug-eluting and three-dimensional printing of airway stents present promising solutions to the challenges of the physical and anatomical constraints of the tracheobronchial tree. Biodegradable stents could also be a solution for the treatment of nonmalignant airway obstruction.

Tracheal fistula repair with stent placement after failure of reconstruction with muscle tissue. A lung cancer surgery complication

A report a case of a 63 year old male diagnosed with lung cancer adenocarcinoma. The patient had a right paratracheal mass diagnosed with EBUS-TBNA 22G. The patient had surgery, however 7 days after the billau catheter was removed pneumothorax was diagnosed which did not resolved. Bronchoscopy reveled two minor fistulas in the interior wall of the trachea. An additional surgery was performed in order to add muscle patches on the exterior part of the trachea. Unfortunately additional stent placement was placed after a silicon stent since the muscle patches failed. We chose a metallic auto expandable stent since after three months of follow up a small metastatic lesion was observed in the liver. Stent placement is an option for these patients and the right stent has to be placed for each case.

Bortezomib sensitivity is tissue dependent and high expression of the 20S proteasome precludes good response in malignant pleural mesothelioma

Background

Bortezomib is an approved proteasome inhibitor for the treatment of certain lymphoma subtypes. Two clinical trials investigated bortezomib in patients with malignant pleural mesothelioma (MPM) and failed to improve outcome. We present a potential explanation for this event.

Methods

171 patients with MPM were analyzed for their mRNA expression of proteasomal subunits PSMA1, PSMA5, PSMB1, PSMB2, PSMB4 and PSMB5 via qPCR (n=84) or sequencing (n=87 TCGA/cBioPortal data set “Mesothelioma”). Outcome and subunit expression were correlated. Four mesothelial and one fibroblast cell line were treated with bortezomib and cisplatin. Cellular response was measured after 0, 6, 12, 24, 48 and 72 hrs. Enzyme activity of proteasomal subunits was assessed via functional enzyme activity assays.

Results

Patients with MPM presented with elevated expression of proteasomal subunits compared to benign controls (p<0.001). PSMB4 correlated with outcome (Cox propotiortional-hazards model (COXPH): p<0.0175, TCGA/cBioPortal data). In cell lines, apoptosis was the main event with a peak after 48 hr incubation for bortezomib or cisplatin. Only two cell lines with comparably low proteasome activity (PSMB2 and PSMB5) responded to 50 nM and 100 nM bortezomib better than to cisplatin (MRC-5, NCI-H2052). MSTO-211H responded to cisplatin only, whereas the other two cell lines were considered therapy resistant (Met-5A, NCI-H2452).

Interpretation

Two clinical trials testing bortezomib in MPM failed, although MPM presents with high proteasome expression, which predicts bortezomib sensitivity in several tumors. Bortezomib induced apoptosis in MPM cell lines with low proteasome activity only. Bortezomib is not suitable for the treatment of MPM, and biomarker-based stratification could have improved both clinical trials.

Trial registration

NCT00513877 and NCT00458913

Macrophage-secreted TGF-β1 contributes to fibroblast activation and ureteral stricture after ablation injury

Iatrogenic injury to the healthy ureter during ureteroscope-guided ablation of malignant or nonmalignant disease can result in ureteral stricture. Transforming growth factor (TGF)-β1-mediated scar formation is considered to underlie ureteral stricture, but the cellular sources of this cytokine and the sequelae preceding iatrogenic stricture formation are unknown. Using a swine model of ureteral injury with irreversible electroporation (IRE), we evaluated the cellular sources of TGF-β1 and scar formation at the site of injury and examined in vitro whether the effects of TGF-β1 could be attenuated by pirfenidone. We observed that proliferation and α-smooth muscle actin expression by fibroblasts were restricted to injured tissue and coincided with proliferation of macrophages. Collagen deposition and scarring of the ureter were associated with increased TGF-β1 expression in both fibroblasts and macrophages. Using in vitro experiments, we demonstrated that macrophages stimulated by cells that were killed with IRE, but not LPS, secreted TGF-β1, consistent with a wound healing phenotype. Furthermore, using 3T3 fibroblasts, we demonstrated that stimulation with paracrine TGF-β1 is necessary and sufficient to promote differentiation of fibroblasts and increase collagen secretion. In vitro, we also showed that treatment with pirfenidone, which modulates TGF-β1 activity, limits proliferation and TGF-β1 secretion in macrophages and scar formation-related activity by fibroblasts. In conclusion, we identified wound healing-related macrophages to be an important source of TGF-β1 in the injured ureter, which may be a paracrine source of TGF-β1 driving scar formation by fibroblasts, resulting in stricture formation.

Setting out the frame conditions for feasible use of FFPE derived RNA

INTRODUCTION

The usage of formalin-fixed paraffin embedded (FFPE) tissue is characterized by its long shelf-life and simple handling. Therefore it is the most commonly available tissue specimen in routine diagnostics and histological studies. Formaldehyde fixation may result in RNA degradation and cross linking with proteins, while storage conditions also affect RNA integrity. The present study was designed to investigate the influence of these factors on RNA analysis.

DESIGN

FFPE-derived RNA from sections of 23 patients with spontaneous pneumothoraxes was used. Unstained sections of FFPE tissue were stored at various temperatures (-80 °C, -20 °C, 4 °C, 24 °C) prior to RNA extraction. The potential impact on RNA quality of semi-automatic and manual RNA isolation and three different deparaffinization agents (mineral oil, xylene and d-limonene) were compared.

RESULTS

The storage temperature of FFPE sections affects RNA concentration and fragmentation, with the optimal storage temperature below -20 °C. The RNA extracted with d-limonene shows equivalent quality to the RNA extracted using more toxic standard agents. The manual isolation provides a higher RNA yield compared to the semi-automatic isolation. However, no differences in the amount of longer RNA fragments were observed. Furthermore, the semi-automatic isolation showed an enhanced RNA quality.

CONCLUSION

FFPE sections not directly used for RNA extraction should be stored below -20 °C to increase quality and yield of the RNA. Usage of semi-automatic isolation produces superior results and simplifies routine processes by having less hands-on-time. Replacement of toxic xylene by d-limonene may contribute to improved occupational safety while not influencing analytical results.

Idiopathic Pulmonary Fibrosis and Antifibrotic Treatments: Focus on Experimental Studies

Context.—

Idiopathic pulmonary fibrosis (IPF) is a progressive fatal disease that up to now has been associated with a poor outcome. Some advances have been made in understanding the multiple interrelated pathogenic pathways underlying IPF. The disease is now believed to result from complex interactions among genetic, epigenetic, transcriptional, posttranscriptional, metabolic, and environmental factors. The discovery and validation of theranostic biomarkers are necessary to enable a more precise and earlier diagnosis of IPF and to improve the prediction of future disease behavior. Two drugs recently approved by the US Food and Drug Administration, pirfenidone and nintedanib, have shown the ability to reduce the progression of the disease, although survival benefits are only minimal and neither drug prevents or reverses the disease.

Objective.—

To provide a critical overview of the main experimental studies carried out for testing the principal effects of pirfenidone and nintedanib on IPF.

Data Sources.—

Experimental (animal and in vitro) studies concerning both drugs were used.

Conclusions.—

Pirfenidone has a longer history of preclinical experimental studies than nintedanib. Many studies have been reported more recently (after 2014) and some of them evaluated the association of both drugs, thus suggesting their combination in future therapeutic approaches. Future investigations focusing on targets at molecular, cellular, and tissue levels are necessary to have a better in-depth knowledge of the properties of these drugs and to explore the potential efficacy of both or other drug combinations.

Innovative use of a Montgomery cannula in the bronchoscopic management of tracheal stenosis and failed tracheostomy decannulation

Background

Endoprosthesis are being used in the everyday clinical practice either as a permanent solution or transient. They can be used in both benign and malignant situations.

Case presentation

We report a case in which a temporary Montgomery cannula is used in conjunction with therapeutic bronchoscopy to manage a patient with failed tracheostomy decannulation secondary to a distal complex tracheal stenosis.

Conclusions

This innovative use of the Montgomery cannula allowed for successful management of the patient's tracheal stenosis and subsequent tracheostomy tube decannulation.

Survival and Quality of Life Benefit after Endoscopic Management of Malignant Central Airway Obstruction

Background: Although interventional management of malignant central airway obstruction (mCAO) is well established, its impact on survival and quality of life (QoL) has not been extensively studied.

Aim: We prospectively assessed survival, QoL and dyspnea (using validated EORTC questionnaire) in patients with mCAO 1 day before interventional bronchoscopy, 1 week after and every following month, in comparison to patients who declined this approach.

Material/Patients/Methods: 36 patients underwent extensive interventional bronchoscopic management as indicated, whereas 12 declined. All patients received full chemotherapy and radiotherapy as indicated. Patients of the 2 groups were matched for age, comorbidities, type of malignancy and level of obstruction. Follow up time was 8.0±8.7 (range 1-38) months.

Results: Mean survival for intervention and control group was 10±9 and 4±3 months respectively (p=0.04). QoL improved significantly in intervention group patients up to the 6^th month (p<0.05) not deteriorating for those surviving up to 12 months. Dyspnea decreased in patients of the intervention group 1 month post procedure remaining reduced for survivors over the 12th month. Patients of the control group had worse QoL and dyspnea in all time points.

Conclusions: Interventional management of patients with mCAO, may achieve prolonged survival with sustained significant improvement of QoL and dyspnea.

Drug Eluting Stents for Malignant Airway Obstruction: A Critical Review of the Literature

Lung cancer being the most prevalent malignancy in men and the 3(rd) most frequent in women is still associated with dismal prognosis due to advanced disease at the time of diagnosis. Novel targeted therapies are already on the market and several others are under investigation. However non-specific cytotoxic agents still remain the cornerstone of treatment for many patients. Central airways stenosis or obstruction may often complicate and decrease quality of life and survival of these patients. Interventional pulmonology modalities (mainly debulking and stent placement) can alleviate symptoms related to airways stenosis and improve the quality of life of patients. Mitomycin C and sirolimus have been observed to assist a successful stent placement by reducing granuloma tissue formation. Additionally, these drugs enhance the normal tissue ability against cancer cell infiltration. In this mini review we will concentrate on mitomycin C and sirolimus and their use in stent placement.

Sirolimus-eluting dextran and polyglutamic acid hybrid coatings on AZ31 for stent applications

Magnesium (Mg)-based cardiovascular stents are promising candidate as the next generation of novel stents. Clinical studies have revealed encouraging outcomes, but late restenosis and thrombogenesis still largely exist. Blood and vascular biocompatible coatings with drug-eluting features could be the solution to such problems.

OBJECTIVE

This study was to investigate the feasibility of a three-layer hybrid coating on Mg alloy AZ31 with sirolimus-eluting feature for cardiovascular stent application.

MATERIALS AND METHODS

The first and third layers were low molecular weight dextran loaded with sirolimus, and the second layer was polyglutamic acid (PGA) to control sirolimus release. The hybrid coating was verified by scanning electron microscope (SEM). DC polarization and immersion tests were used to evaluate corrosion rate of the materials. Indirect cell viability and cell proliferation tests were performed by culturing cells with extract solutions of AZ31 samples. Blood compatibility was assessed using hemolysis assay.

RESULTS

Coated samples had an enhanced corrosion resistance than that of uncoated controls, more PGA slower corrosion. Sirolimus had a burst release for the initial ∼3 days and then a slower release until reached a plateau. The PGA thickness was able to control the sirolimus release, the thicker of PGA the slower release. The overall cell viability was extract concentration-dependent, and improved by the hybrid coatings. Cell proliferation was correlated to coating thickness and was inhibited by sirolimus. In addition, all coated AZ31 samples were non-hemolytic.

CONCLUSION

Results demonstrated that such a three-layer hybrid coating may be useful to improve the vascular biocompatibility of Mg stent materials.

Experimentation with aerosol bonsetan, pirfenidone, treprostinil and sidenafil

INTRODUCTION

Pulmonary hypertension (PH) has been identified either as a symptom or a primary entity. Several drugs are already on the market and other are being investigated. Idiopathic pulmonary fibrosis (IPF) is also a disease were several drugs are being investigated.

MATERIALS AND METHODS

Three jet nebulizers and three ultrasound nebulizers were used for our experiments with seven different residual cups and four different loadings. Bonsetan, treprostinil, sidenafil and pirfenidone were modified in order to be produced as aerosol in an effort to identify parameters which influence the droplet size production size.

RESULTS

The four-way ANOVA on droplet size using the jet nebulizers revealed two statistically significant factors, drug (F=6.326, P=0.0007) and residual cup (F=4.419, P=0.0007), and their interaction term (F=5.829, P<0.0001). Drugs bonsetan and pirfenidone produce equally the lowest mean droplet size (2.63 and 2.80 respectively) as compared to other two drug mean sizes. The ANOVA results, concerning the ultrasound nebulizers, revealed only the nebulizers as producing significant effect on droplet size (F=4.753, P=0.037).

DISCUSSION

Our study indicates the importance of the initial drug design formulation. Moreover, further investigation of the residual cup design is an additional parameter that can assist in the optimal droplet size production, indifferently of the drug formulation.