Nitric oxide, a survival factor for lens epithelial cells

Purpose: Nitric oxide (NO) is capable of promoting either cell death or cell survival depending on cell type and experimental conditions. In this study, the possible effects of NO on the viability of lens epithelial cells were investigated in an explant model used previously to identify cellular changes associated with posterior capsule opacification following cataract surgery. Methods: Rat lens epithelial explants prepared from weanling rats were cultured in a serum-free medium for five days with or without the addition of the nitric oxide synthase inhibitor, L-Nω-nitro-L-arginine methyl ester (L-NAME), using the inactive enantiomer D-NAME as a control. Alternatively, explants were cultured for nine days with or without the NO donor, sodium nitroprusside. Explants were assessed morphologically and immunohistochemically or by determining DNA content. Results: In the presence of L-NAME but not in controls, progressive rounding up and detachment of cells from the lens capsule occurred, leading to extensive cell loss. Affected cells showed apoptosis-like cell-surface blebbing and nuclear fragmentation. Conversely, inclusion of sodium nitroprusside suppressed the morphological changes and spontaneous cell loss that occurred when sparsely covered explants were cultured for nine days, increased cell coverage fourfold during that period, and prevented the expression of the transdifferentiation markers α-smooth muscle actin and fibronectin. In addition, whereas L-NAME exacerbated cell loss induced by culturing with 50 pg/ml transforming growth factor-β2, sodium nitroprusside offered protection. Conclusions: This study points to a previously unidentified role for NO as an endogenously produced survival factor for lens epithelial cells, raising the possibility of using NO deprivation as a means of removing residual lens cells following cataract surgery and thereby preventing posterior capsule opacification

Die hereditäre hemorrhagische Telangiektasie: Untersuchungen zur Multiorganbeteiligung bei Patienten mit Epistaxis als Leitsymptom

Die hereditäre hämorrhagische Telangiektasie (Morbus Rendu-Osler-Weber) ist ein autosomal-dominant vererbtes vaskuläres Fehlbildungssyndrom. Hierbei werden multiple arteriovenöse Malformationen (AVM) im Bereich der Schleimhaut der oberen Luft- und Speisewege sowie der Haut beobachtet. Darüber hinaus können andere Organe befallen sein wie z.B. Lunge, Leber und ZNS. Die Diagnose HHT sollte nach den Empfehlungen des Scientific Advisory Board der HHT Foundation International auf der Basis verschiedener klinischer Befunde und der Familienanamnese (sogenannten Curaçao-Kriterien) gestellt werden. Nahezu alle an einer HHT erkrankten Patienten leiden unter rezidivierenden Epistaxisepisoden. Hierdurch bedingt kann die Erstdiagnose der Erkrankung häufig durch den HNO-Arzt gestellt werden. Dem HNO-Arzt kommt somit eine entscheidende Rolle in der Einleitung weiterer diagnostischer Maßnahmen zur Feststellung okkulter AVM zu. Im Rahmen der vorliegenden Untersuchung boten wir 51 Patienten mit rezidivierender Epistaxis, bei denen die Diagnose bzw. Verdachtsdiagnose HHT bestand, die Möglichkeit an, sich auf AVM der inneren Organen untersuchen zu lassen. In fünf Fällen konnte die Diagnose der HHT ausgeschlossen werden. Zusätzlich zu der Endoskopie der oberen Luft- und Speisewege wurden ein CT des Thorax, ein MRT vom Schädel und eine Sonographie des Abdomens sowie Blut- und Urinuntersuchungen durchgeführt. Des weiteren erfolgte eine augenärztliche Untersuchung. Mehr als die Hälfte unserer Patienten wiesen bislang okkulte vaskuläre Malformationen der inneren Organen auf, davon waren wiederum die Hälfte therapiebedürftig

PAR4 (Protease-Activated Receptor 4) Antagonism with BMS-986120 Inhibits Human Ex Vivo Thrombus Formation

Objective-BMS-986120 is a novel first-in-class oral PAR4 (protease-Activated receptor 4) antagonist with potent and selective antiplatelet effects. We sought to determine for the first time, the effect of BMS-986120 on human ex vivo thrombus formation. Approach and Results-Forty healthy volunteers completed a phase 1 parallel-group PROBE trial (Prospective Randomized Open-Label Blinded End Point). Ex vivo platelet activation, platelet aggregation, and thrombus formation were measured at 0, 2, and 24 hours after (1) oral BMS-986120 (60 mg) or (2) oral aspirin (600 mg) followed at 18 hours with oral aspirin (600 mg) and oral clopidogrel (600 mg). BMS-986120 demonstrated highly selective and reversible inhibition of PAR4 agonist peptide (100 μM)-stimulated P-selectin expression, platelet-monocyte aggregates, and platelet aggregation (P<0.001 for all). Compared with pretreatment, total thrombus area (μm2/mm) at high shear was reduced by 29.2% (95% confidence interval, 18.3%-38.7%; P<0.001) at 2 hours and by 21.4% (9.3%-32.0%; P=0.002) at 24 hours. Reductions in thrombus formation were driven by a decrease in platelet-rich thrombus deposition: 34.8% (19.3%-47.3%; P<0.001) at 2 hours and 23.3% (5.1%-38.0%; P=0.016) at 24 hours. In contrast to aspirin alone, or in combination with clopidogrel, BMS-986120 had no effect on thrombus formation at low shear (P=nonsignificant). BMS-986120 administration was not associated with an increase in coagulation times or serious adverse events. Conclusions-BMS-986120 is a highly selective and reversible oral PAR4 antagonist that substantially reduces platelet-rich thrombus formation under conditions of high shear stress. Our results suggest PAR4 antagonism has major potential as a therapeutic antiplatelet strategy. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT02439190

Predictors of Nodal and Metastatic Failure in Early Stage Non-Small Cell Lung Cancer after Stereotactic Body Radiation Therapy

Introduction/Background Many early-stage non-small cell lung cancer (ES-NSCLC) patients undergoing stereotactic body radiation therapy (SBRT) develop metastases, which is associated with poor outcomes. We sought to identify factors predictive of metastases after lung SBRT and created a risk stratification tool. Materials and Methods We included 363 patients with ES-NSCLC who received SBRT; median follow-up was 5.8 years. The following patient and tumor factors were retrospectively analyzed for their association with metastases (defined as nodal and/or distant failure): sex; age; lobe involved; centrality; previous NSCLC; smoking status; gross tumor volume (GTV); T-stage; histology; dose; minimum, maximum, and mean GTV dose; and parenchymal lung failure. A metastasis risk-score linear-model using beta coefficients from a multivariate Cox model was built. Results A total of 111/406 (27.3%) lesions metastasized. GTV volume and dose were significantly associated with metastases on univariate and multivariate Cox proportional hazards modeling (p<0.001 and HR=1.02 per mL, p<0.05 and HR=0.99 per Gy, respectively). Histology, T-stage, centrality, lung parenchymal failures, and previous NSCLC were not associated with development of metastasis. A metastasis risk-score model using GTV volume and prescription dose was built: [risk score=(0.01611 x GTV)–(0.00525 x dose (BED10))]. Two risk-score cutoffs separating the cohort into low-, medium-, and high-risk subgroups were examined. The risk-score identified significant differences in time to metastases between low-, medium-, and high-risk patients (p<0.001), with 3-year estimates of 81.1%, 63.8%, and 38%, respectively. Conclusion GTV volume and radiation dose are associated with time to metastasis and may be used to identify patients at higher risk of metastasis after lung SBRT