The empty pelvis syndrome: a core data set from the PelvEx collaborative

BACKGROUND

Empty pelvis syndrome (EPS) is a significant source of morbidity following pelvic exenteration (PE), but is undefined. EPS outcome reporting and descriptors of radicality of PE are inconsistent; therefore, the best approaches for prevention are unknown. To facilitate future research into EPS, the aim of this study is to define a measurable core outcome set, core descriptor set and written definition for EPS. Consensus on strategies to mitigate EPS was also explored.

METHOD

Three-stage consensus methodology was used: longlisting with systematic review, healthcare professional event, patient engagement, and Delphi-piloting; shortlisting with two rounds of modified Delphi; and a confirmatory stage using a modified nominal group technique. This included a selection of measurement instruments, and iterative generation of a written EPS definition.

RESULTS

One hundred and three and 119 participants took part in the modified Delphi and consensus meetings, respectively. This encompassed international patient and healthcare professional representation with multidisciplinary input. Seventy statements were longlisted, seven core outcomes (bowel obstruction, enteroperineal fistula, chronic perineal sinus, infected pelvic collection, bowel obstruction, morbidity from reconstruction, re-intervention, and quality of life), and four core descriptors (magnitude of surgery, radiotherapy-induced damage, methods of reconstruction, and changes in volume of pelvic dead space) reached consensus-where applicable, measurement of these outcomes and descriptors was defined. A written definition for EPS was agreed.

CONCLUSIONS

EPS is an area of unmet research and clinical need. This study provides an agreed definition and core data set for EPS to facilitate further research.

Proteomic, miRNA and bacterial biomarker patterns in atopic dermatitis patients and their course upon anti-IL-4Rα therapy

BACKGROUND

Identification of biomarkers is required for a systems medicine approach and personalized treatment in atopic dermatitis (AD). These biomarkers may not only aid in diagnosing but also might be suitable to predict the effectiveness of targeted treatment.

OBJECTIVE

We aimed to identify proteomic, microbial and miRNA biomarkers in AD patients and investigated their course in relation to the clinical response upon anti-IL-4Rα therapy.

METHODS

Proteomic and miRNA screening was performed in AD patients in comparison to healthy controls. Differentially regulated serum proteins, miRNA and selected skin microbiota were measured consecutively in 50 AD patients before and upon systemic dupilumab treatment. A random forest classifier was used to predict the outcome of dupilumab therapy based on the initial biomarker patterns.

RESULTS

We identified 27 proteomic candidates, miRNA and three microbial strains to be dysregulated in AD. CCL17, CCL13, CCL22, E-selectin and BDNF were differently regulated and significantly associated with treatment response. In contrast, neither the microbial composition nor the miRNA pattern was associated with treatment response upon dupilumab treatment.

CONCLUSION

AD patients display defined dysregulations regarding their systemic proteomic serum profile, miRNA patterns and their skin microbiome. The proteomic profile and selected skin bacteria changed profoundly upon anti-IL-4Rα therapy which was associated with an overall clinical response. This was not seen in miRNA-related biomarkers. Our findings support the hypothesis that biomarker profiles reflect treatment responses and may in the future be used to develop a personalized medicine approach for the treatment of AD patients.

Penile cavernous sinusoids are Prox1-positive hybrid vessels

Endothelial cells (ECs) of blood and lymphatic vessels have distinct identity markers that define their specialized functions. Recently, hybrid vasculatures with both blood and lymphatic vessel-specific features have been discovered in multiple tissues. Here, we identify the penile cavernous sinusoidal vessels (pc-Ss) as a new hybrid vascular bed expressing key lymphatic EC identity genes Prox1, Vegfr3,and Lyve1. Using single-cell transcriptome data of human corpus cavernosum tissue, we found heterogeneity within pc-S endothelia and observed distinct transcriptional alterations related to inflammatory processes in hybrid ECs in erectile dysfunction associated with diabetes. Molecular, ultrastructural, and functional studies further established hybrid identity of pc-Ss in mouse, and revealed their morphological adaptations and ability to perform lymphatic-like function in draining high-molecular-weight tracers. Interestingly, we found that inhibition of the key lymphangiogenic growth factor VEGF-C did not block the development of pc-Ss in mice, distinguishing them from other lymphatic and hybrid vessels analyzed so far. Our findings provide a detailed molecular characterization of hybrid pc-Ss and pave the way for the identification of molecular targets for therapies in conditions of dysregulated penile vasculature, including erectile dysfunction.

Immune-interacting lymphatic endothelial subtype at capillary terminals drives lymphatic malformation

Oncogenic mutations in PIK3CA, encoding p110α-PI3K, are a common cause of venous and lymphatic malformations. Vessel type-specific disease pathogenesis is poorly understood, hampering development of efficient therapies. Here, we reveal a new immune-interacting subtype of Ptx3-positive dermal lymphatic capillary endothelial cells (iLECs) that recruit pro-lymphangiogenic macrophages to promote progressive lymphatic overgrowth. Mouse model of Pik3caH1047R-driven vascular malformations showed that proliferation was induced in both venous and lymphatic ECs but sustained selectively in LECs of advanced lesions. Single-cell transcriptomics identified the iLEC population, residing at lymphatic capillary terminals of normal vasculature, that was expanded in Pik3caH1047R mice. Expression of pro-inflammatory genes, including monocyte/macrophage chemokine Ccl2, in Pik3caH1047R-iLECs was associated with recruitment of VEGF-C-producing macrophages. Macrophage depletion, CCL2 blockade, or anti-inflammatory COX-2 inhibition limited Pik3caH1047R-driven lymphangiogenesis. Thus, targeting the paracrine crosstalk involving iLECs and macrophages provides a new therapeutic opportunity for lymphatic malformations. Identification of iLECs further indicates that peripheral lymphatic vessels not only respond to but also actively orchestrate inflammatory processes.

Comparison of the antiarrhythmic potential of doxapram and its metabolite ketodoxaparam

Background

A few years ago, the TASK-1 channel has been established as a potential new target for the therapy of atrial fibrillation (AF). In the heart, TASK-1 is almost exclusively expressed in the atria and is significantly upregulated in AF patients. Therefore, it plays an important role in the shortening of the atrial action potential observed during AF, making TASK-1 a promising target for AF therapy. This could be proven in a porcine model of persistent AF in which an intravenous application of the TASK-1 inhibitor doxapram led to a termination of AF and the restoration of sinus rhythm (SR). Doxapram's metabolite ketodoxapam is described in the literature as being active with limited data available on its usage. Therefore, the effect of ketodoxapram on TASK-1 and its possible use in AF therapy still needs to be investigated.

Purpose

The purpose of the present study was to assess the potential of ketodoxapram in the termination of AF. Furthermore, a comparison between doxapram and ketodoxapram was performed based on electrophysiological and pharmacological data.

Methods

UPLC-MS/MS assays were developed and validated for the measurement of doxapram and ketodoxapram in porcine plasma and brain tissue. Using these assays, the pharmacokinetics of both substances, after intravenous injections of 1 mg/kg, were determined in pigs. Furthermore, brain and plasma concentrations were measured to assess brain-to-plasma ratios. A porcine AF model was used to estimate the antiarrhythmic potential. Electrophysiological properties were evaluated, using two-electrode voltage clamp experiment on Xenopus laevis oocytes which heterologously expressed atrial potassium channels, to calculate the effect of doxapram and ketodoxapram on channel function. Furthermore, whole-cell patch clamp measurements were performed on isolated human cardiomyocytes.

Results

Doxapram and ketodoxapram showed strong inhibitory effects on TASK-1 (IC50 1.0 μM and 0.8 μM) and TASK-3 (5.9 μM and 1.5 μM), but no significant effect on the other measured ion channels. The maximal inhibition on TASK-1 was 96%. The brain-to-plasma ratio for doxapram (0.58) was almost ten-fold higher than for ketodoxapram (0.065), hinting at a reduced crossing of the blood-brain barrier (BBB) for ketodoxapram. The terminal half-life (t1/2) of ketodoxapram (1.71 h) was longer and the maximal concentration (Cmax; 4,604 ng/ml) was higher than for doxapram (1.38 h; 1,780 ng/ml). In a porcine model of AF, ketodoxapram led to a significantly reduced AF burdens comparable to doxapram.

Conclusions

Doxapram and ketodoxapram both show strong inhibitory effects on TASK-1, making them good candidates for a TASK-1 based AF therapy. Ketodoxapram with its longer t1/2, reduced crossing of the BBB and higher Cmax points towards a possible superiority in the treatment of AF compared to doxapram. Studies in a porcine AF model showed promising results for the use of doxapram and ketodoxapram in AF therapy.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): German Research Foundation

Dapagliflozin exhibits class I antiarrhythmic effects which suppress action potential formation in human atrial cardiomyocytes

Background

Recently, inhibitors of sodium-glucose transporter 2 (SGLT2i) were shown to have tremendous cardioprotective effects in patients with type 2 diabetes mellitus (T2DM) as well as heart failure (HF) patients, regardless of their glycemic status. Among other beneficial effects on cardiovascular outcome an antiarrhythmic effect of SGLT2i was indicated. In patients with T2DM therapy with SGLT2i was associated with a significantly reduced risk of atrial arrhythmias and sudden cardiac death. As sodium-glucose transporter 2 (SGLT2) is not expressed within the heart underlying molecular modes of action remain unclear. Therefore, investigating possible antiarrhythmic mechanisms is crucial to determine whether SGLT2i might be beneficial for all patients suffering from arrhythmias, regardless of other comorbidities.

Purpose

To assess antiarrhythmic effects of SGLT2i on a molecular and cellular level. Therefore, direct electrophysiological effects of dapagliflozin – the most advanced SGLT2i in clinical trials – on action potential (AP) formation in atrial cardiomyocytes (CM) was investigated.

Methods

Effects of dapagliflozin on human NaV1.5, heterologously expressed in Chinese hamster ovary (CHO) cells, was investigated using the patch-clamp method. Further, effects on voltage-gated sodium channels (NaV) were also measured in human atrial CM. Consequences of dapagliflozin treatment on AP formation were studied on isolated human and porcine atrial CM using the patch-clamp technique. APs were elicited in current-clamp mode by injection of brief current pulses.

Results

Dapagliflozin (100 μM) significantly decreased peak sodium currents in human atrial CM as well as CHO cells, expressing human NaV1.5 channel subunits. Additionally, half-activation potential of voltage-gated sodium channels was significantly increased after administration of dapagliflozin. Furthermore, dapagliflozin (100 μM) suppressed AP formation in CM isolated from human and porcine left and right atrial tissue. In human CM action potential amplitude (APA) was significantly reduced by 34.3%, while APA inhibition by dapagliflozin averaged out at 30.7% for porcine CM. In porcine CM action potential duration at 50% (APD50) and 90% repolarization (APD90) were also significantly reduced.

Conclusion

Dapagliflozin suppresses AP formation in human and porcine atrial CM by inhibiting voltage-gated sodium currents. Therefore, we suppose that dapagliflozin exhibits class I antiarrhythmic effects.

Funding Acknowledgement

Type of funding sources: None.

Evaluating the reversibility potential of atrial cardiomyopathy on a clinical and cellular level

Background

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and is associated with various remodelling processes of the electrical and structural properties of the atrium, collectively referred to as atrial cardiomyopathy. Because these remodelling processes contribute significantly to the high recurrence rates and chronification of AF, the exact time course of their development and their reversion potential need to be further characterized.

Purpose

To investigate the time course and reversibility of atrial cardiomyopathy on a clinical, cellular and molecular level.

Methods

A clinically relevant porcine large animal model was used to study the structural and functional implications of atrial cardiomyopathy after different periods of burst pacing-induced AF (2, 4 and 8 weeks) and after a recovery period, following electrical cardioversion. The pigs were clinically characterized at each time point by echocardiography, cardiac MRI, and electrophysiological studies. After extraction of the heart, action potentials (APs) and ionic currents were measured on isolated atrial cardiomyocytes (CM) using the patch-clamp technique.

Results

After 4 weeks of AF induction, APD90 of isolated atrial cardiomyocytes was attenuated by 26%. Extending the AF induction period to 8 weeks caused an even stronger APD90 reduction by one-third, compared to SR controls. Accompanying, the TASK-1 current density was strongly upregulated in AF pigs. Those observations were in line with significant changes of the right atrial effective refractory period (AERP). At baseline, AERPS1=400 ms yielded 186 ms, whereas it was reduced to 141 ms after eight weeks of AF. Addressing the reversibility of those changes, following cardioversion of AF and an 8 week long SR recovery period, AERP baseline values were almost restored. Likewise, APD90 shortening was partially reversed. Furthermore, indication of reversibility of AF-associated remodelling was also observed on a structural level. After eight weeks of AF induction, echocardiography revealed severe dilatation of both atria, whereas atrial diameters decreased significantly after restoration of SR.

Conclusion

Remodelling processes underlying atrial cardiomyopathy display a partial reversibility upon restoration and maintenance of SR.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DFG German Research Foundation

Atrial tattoos lines: a new method to terminate atrial fibrillation

Introduction

Atrial fibrillation (AF) is the most common cardiac arrhythmia affecting more than 4% of the world's population. Furthermore, the vulnerable substrate underlying atrial cardiomyopathy remains far from being understood. Atrial cardiomyopathy is a highly complex and heterogeneous disease that occurs in the context of various clinical backgrounds, which explains the heterogenous success of established atrial ablation strategies such as pulmonary vein isolation. Here we developed a new interventional method for the treatment of AF using a tattooing procedure of silver nanowires in the atria to create circular lines of increased conductivity to prevent irregular electrical propagation.

Purpose

In a translational study, we tested a newly developed interventional method to terminate AF by injecting lines of silver nanowires to increase tissue conductivity.

Methods

The developed tattoo method was tested in vivo using an established large animal AF model of the domestic pig. Pigs (n=10) with atrial fibrillation were either treated with right atrial tattoo lines using a transmural injection procedure of silver nanowires as closed lines in the atrium or got a sham treatment with saline injections. Over 21 days, AF was induced and monitored (AF burden) by an intracardiac dual-chamber device with a biofeedback induction algorithm. Initially and before final termination, conventional electrophysiological investigation and atrial 3D mapping, echocardiography and epicardial multi electrode array (MEA) measurements were performed. Following the 21 days observation period, the heart was extracted and freshly isolated atrial cardiomyocytes were subjected to cellular electrophysiological, molecular and histochemical characterization. Electrophysiological data was used for in silico modelling of arrhythmia termination and wave propagation. The study protocol was approved by the animal ethics committee.

Results

The AF burden was significantly reduced (AF burden <10%) in the group treated with the new atrial tattoo line method compared to sham treated pigs. The bi-atrial diameters, quantified by echocardiography, were significantly smaller in the treatment group. Atrial refractory period was significantly shorter in the sham treated pigs. A significant increase of connexin 43 was observed in the injection area of silver nanowires in the myocardium. Measurements with MEA demonstrated increased conduction velocity by a factor of 1.5–2.0 in the areas of silver nanowire injections. Additionally, in silico modelling showed the termination of AF via the created conduction lines.

Conclusion

The newly developed interventional method of the creation of atrial lines with increased tissue conductivity using silver nanowires could successfully terminate AF in pigs. Perspectively, this new myocardial tattooing technique may be a promising treatment strategy for patients with complex atrial cardiomyopathies to terminate atrial arrhythmias.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Else Kröner Fresenius Foundation

The COVID-19 viral 3a protein forms a potassium channel that can be inhibited by antiarrhythmic drugs

Funding Acknowledgements

Type of funding sources: Public Institution(s). Main funding source(s): Deutsche Gesellschaft für Kardiologie /German Cardiac Society Joachim Herz Stiftung /Joachim Herz Foundation

Background/Introduction

Supraventricular and ventricular arrhythmias can often be observed in patients with COVID-19 infection. Both, the clinically observed increase in cardiac biomarkers as well as histological studies indicate virus replication within cardiomyocytes. The 3a open reading frame of the viral genome encodes for a transmembrane protein that is transported to the cell membrane where it can serve as a potassium channel.

Purpose

The aim of this study was to investigate whether COVID-19 infected induced pluripotent stem cell (iPSC)-derived cardiomyocytes also express the 3a protein and whether the potassium currents that are conducted through the 3a protein can be inhibited by clinically used antiarrhythmic drugs.

Methods and Results

iPSC-derived cardiomyocytes were infected with COVID-19 and subsequently subjected to immunoblotting, where expression of the 3a protein could be observed. Plasmid DNA, encoding the COVID-19 3a protein, was generated by gene synthesis and used for in vitro transcription of cRNA. 3–5 days after intracytoplasmic injection of the 3a protein cRNA into Xenopus laevis oocytes, potassium currents could be measured by two-electrode voltage clamp recordings. While class I and class IV antiarrhythmic drugs showed only minor effects on the potassium currents of the 3a protein, a robust inhibition by several beta-blockers and by class III antiarrhythmic drugs could be observed. The strongest effects were found with dofetilide (58.1 % inhibition at 100 µM) and amiodarone (50.1 % inhibition at 100 µM, IC50 level 4.7 µM). An in silico docking analysis, based on the recently revealed crystal structure of the 3a protein, identified the amino acid residues K61 and D142 as part of the binding site of amiodarone. After deactivation of these amino acid residues by site-directed mutagenesis, the inhibition by amiodarone was significantly attenuated.

Conclusion

The COVID-19 viral 3a protein is expressed in COVID-19-infected iPS-derived cardiomyocytes and forms a potassium channel that can be inhibited by antiarrhythmic drugs.

Paradoxical effects of cigarette smoke and COPD on SARS-CoV-2 infection and disease

BACKGROUND

How cigarette smoke (CS) and chronic obstructive pulmonary disease (COPD) affect severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) infection and severity is controversial. We investigated the effects of COPD and CS on the expression of SARS-CoV-2 entry receptor ACE2 in vivo in COPD patients and controls and in CS-exposed mice, and the effects of CS on SARS-CoV-2 infection in human bronchial epithelial cells in vitro.

METHODS

We quantified: (1) pulmonary ACE2 protein levels by immunostaining and ELISA, and both ACE2 and/or TMPRSS2 mRNA levels by RT-qPCR in two independent human cohorts; and (2) pulmonary ACE2 protein levels by immunostaining and ELISA in C57BL/6 WT mice exposed to air or CS for up to 6 months. The effects of CS exposure on SARS-CoV-2 infection were evaluated after in vitro infection of Calu-3 cells and differentiated human bronchial epithelial cells (HBECs), respectively.

RESULTS

ACE2 protein and mRNA levels were decreased in peripheral airways from COPD patients versus controls but similar in central airways. Mice exposed to CS had decreased ACE2 protein levels in their bronchial and alveolar epithelia versus air-exposed mice. CS treatment decreased viral replication in Calu-3 cells, as determined by immunofluorescence staining for replicative double-stranded RNA (dsRNA) and western blot for viral N protein. Acute CS exposure decreased in vitro SARS-CoV-2 replication in HBECs, as determined by plaque assay and RT-qPCR.

CONCLUSIONS

ACE2 levels were decreased in both bronchial and alveolar epithelial cells from COPD patients versus controls, and from CS-exposed versus air-exposed mice. CS-pre-exposure potently inhibited SARS-CoV-2 replication in vitro. These findings urge to investigate further the controversial effects of CS and COPD on SARS-CoV-2 infection.

Paradoxical effects of cigarette smoke and COPD on SARS-CoV2 infection and disease

Introduction

How cigarette smoke (CS) and chronic obstructive pulmonary disease (COPD) affect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and severity is controversial. We investigated the protein and mRNA expression of SARS-CoV-2 entry receptor ACE2 and proteinase TMPRSS2 in lungs from COPD patients and controls, and lung tissue from mice exposed acutely and chronically to CS. Also, we investigated the effects of CS exposure on SARS-CoV-2 infection in human bronchial epithelial cells.

Methods

In Cohort 1, ACE2-positive cells were quantified by immunostaining in FFPE sections from both central and peripheral airways. In Cohort 2, we quantified pulmonary ACE2 protein levels by immunostaining and ELISA, and both ACE2 and TMPRSS2 mRNA levels by RT-qPCR. In C57BL/6 WT mice exposed to air or CS for up to 6 months, pulmonary ACE2 protein levels were quantified by triple immunofluorescence staining and ELISA. The effects of CS exposure on SARS-CoV-2 infection were evaluated after 72hr in vitro infection of Calu-3 cells. After SARS-CoV-2 infection, the cells were fixed for IF staining with dsRNA-specific J2 monoclonal Ab, and cell lysates were harvested for WB of viral nucleocapsid (N) protein. Supernatants (SN) and cytoplasmic lysates were obtained to measure ACE2 levels by ELISA.

Results

In both human cohorts, ACE2 protein and mRNA levels were decreased in peripheral airways from COPD patients versus both smoker and NS controls, but similar in central airways. TMPRSS2 levels were similar across groups. Mice exposed to CS had decreased ACE2 protein levels in their bronchial and alveolar epithelia versus air-exposed mice exposed to 3 and 6 months of CS. In Calu3 cells in vitro, CS-treatment abrogated infection to levels below the limit of detection. Similar results were seen with WB for viral N protein, showing peak viral protein synthesis at 72hr.

Conclusions

ACE2 levels were decreased in both bronchial and alveolar epithelial cells from uninfected COPD patients versus controls, and from CS-exposed versus air-exposed mice. CS-pre-treatment did not affect ACE2 levels but potently inhibited SARS-CoV-2 replication in this in vitro model. These findings urge to further investigate the controversial effects of CS and COPD on SARS-CoV2 infection.

Neuropeptides as novel regulators of human atrial TASK-1 currents

Background/Introduction

The neurokinin-III receptor (NK3R) was recently shown to regulate action potential duration (APD) in atrial cardiomyocytes by inhibition of a background potassium current. In the human heart, TASK-1 (hK2P3.1) two-pore-domain potassium channels display atrial-specific expression. Because of their phospholipase C (PLC)-dependent regulation, TASK-1 channels are a promising candidate to mediate APD prolongation via the Gq-coupled neurokinin-III receptor.

Purpose

To investigate whether TASK-1 channels mediate neurokinin-III receptor activation induced APD prolongation and to dissect the underlying molecular mechanisms.

Methods

Patch clamp measurements were performed in atrial cardiomyocytes isolated from patients with atrial fibrillation. Xenopus laevis oocytes heterologously expressing hTASK-1 and hNK3R were subjected to two-electrode voltage-clamp recordings.

Results

In Xenopus oocytes heterologously overexpressing hNK3R and hTASK-1 administration of substance P or neurokinin B resulted in TASK-1 current inhibition. This could be reproduced by application of the high affinity neurokinin-III receptor agonist senktide. Moreover, preincubation with the neurokinin-III receptor antagonist osanetant blunted the effect of senktide. Pharmacological experiments and mutagenesis studies could show a protein kinase C (PKC)-independent mechanism of TASK-1 current inhibition: upon NK3R activation TASK-1 channels are blocked via Gq-mediated PLC activation, in a DAG-dependent fashion. Finally, effects of senktide on atrial background currents could be reproduced in human atrial cardiomyocytes isolated from patients with atrial fibrillation.

Conclusion

Neurokinin-III receptor stimulation suppresses background potassium currents in isolated human atrial cardiomyocytes from patients with atrial fibrillation. Heterologously expressed human TASK-1 channels are inhibited by neurokinin-III receptor activation in a PLC and DAG dependent fashion, suggesting neuropeptides as novel regulators of human atrial TASK-1 currents.

Central Illustration

Funding Acknowledgement

Type of funding source: None

In-vivo Intradermal Delivery of Co-57 labeled Vitamin B-12, and Subsequent Comparison with Standard Subcutaneous Administration

Vitamin B-12 (cobalamin) deficiency in humans is a worldwide problem emanating from varied causes such as insufficient dietary intake or malabsorption of the micronutrient due to an underlying condition (absence or failure of intrinsic factor, atrophic gastritis, post-operative bariatric surgery, inflammatory bowel disease, cobalt deficiency etc.). As oral supplementation is limited by its bioavailability due to the absorptive property of intrinsic factor, clinicians often prescribe parenteral forms of administration to replenish diminished levels rapidly. The gold standard in parenteral delivery of cobalamin is subcutaneous and/or intramuscular injections. The relatively large molecular size of cobalamin (1355.39 Da) makes passive transdermal patch-based delivery via the stratum corneum quite challenging. Hence, the primary goal of this study is to investigate the feasibility of intradermal (ID) delivery of Vitamin B-12 via an almost painless microneedle injection and subsequent comparison with standard subcutaneous (SC) delivery. This work reports on a custom-made microneedle device built from a commercial insulin needle and it's use to perform ID delivery of Co-57 radiolabeled Vitamin B-12 in-vivo in rabbits. The pharmacokinetic profile and bioavailability were studied and compared with SC delivery. It is the first comprehensive study, to our best knowledge, that compares a micronutrient (eg. Vitamin B-12) delivery via ID and SC routes in-vivo. While the bioavailability for the SC route is found to be slightly higher compared to the ID route (99% vs. 96%), the T_max for both are almost identical. Thus, ID delivery of Vitamin B-12 using a microneedle injection could be a viable and minimally invasive alternative to existing parenteral options.

1206Doxapram is a promising new antiarrhythmic drug for an atrial-specific therapy of atrial fibrillation

Background

TASK-1 (K2P3.1) is an atrial-specific two-pore domain potassium channel that is significantly upregulated in atrial fibrillation (AF) patients resulting in shortened atrial action potential duration (APD). Inhibition of TASK-1 in human atrial cardiomyocytes reverses AF-related APD shortening to values observed in patients with sinus rhythm (SR). By in silico-modelling and experimental characterization of drug binding sites, doxapram was identified as specific inhibitor of TASK-1.

Purpose

In this study, we investigated the antiarrhythmic efficacy of doxapram in a porcine model of AF to convert and suppress AF.

Methods

We established a new porcine model of persistent AF without induced tachymyopathy. AF was induced in domestic pigs by intermittent atrial burst stimulation using implanted pacemakers. During AF episodes, burst stimulation was inhibited by an integrated pacemaker biofeedback algorithm. AV-node ablation was performed to prevent AF-associated heart failure. All pigs underwent catheter-based electrophysiological investigations prior to and after 14 days doxapram treatment. Pigs in the treatment group received intravenous applications of doxapram twice per day. Rhythm status was continuously recorded by intracardiac long-term ECG monitors. The application of doxapram for cardioversion and long term suppression of AF in pigs with persistent AF was evaluated. Subsequent to the doxapram treatment, porcine cardiomyocytes were isolated from right and left atria and electrophysiologically investigated by patch-clamp and multi-electrode experiments. Atrial electrical remodeling was characterized by analyses of ion channel expression at mRNA and protein levels.

Results

TASK-1 mRNA, protein and transmembrane current were significantly increased in AF pigs compared to SR controls, resulting in shortened atrial APDs. In doxapram-treated AF pigs the AF burden was significantly reduced. After 14 days treatment with doxapram, TASK-1 currents and atrial APDs recorded in porcine cardiomyocytes were reduced and similar to values of SR animals. Doxapram could be successfully applied for cardioversion in pigs with persistent AF. On average, cardioversion was observed 3 minutes after doxapram application.

Conclusion

Doxapram significantly suppressed AF episodes and normalized cellular electrophysiological characteristics in a porcine model of AF through inhibition of the TASK-1 ion channel. Furthermore, doxapram rapidly converted AF into SR in pigs. Therefore, doxapram might serve as a new antiarrhythmic drug to treat AF in patients.

P1601N-glycosylation of TREK-1/hK2P2.1 two-pore-domain (K2P) potassium channels

Background and purpose

Mechanosensitive hTREK-1 (hK2P2.1) two-pore-domain potassium channels give rise to background currents that control resting membrane potential in excitable tissue. Recently TREK-1 currents have been linked to regulation of cardiac rhythm as well as hypertrophy and fibrosis. Even though pharmacological and biophysical characteristics of hTREK-1 channels have been widely studied, less is known about its posttranslational modifications. This study aims to evaluate whether hTREK-1 channels are N-glycosylated and whether glycosylation may affect channel functionality.

Experimental approach

Following pharmacological inhibition of N glycosylation, enzymatic digestion or mutagenesis, immunoblots of Xenopus laevis oocytes and HEK-233T cell lysates were used to assess electrophoretic mobility. Two-electrode voltage clamp measurements were employed to study channel function.

Key results

TREK-1 channels subunits undergo N-glycosylation at asparagine residues 110 and 134. The presence of sugar moieties at these two sites increases channel function. Detection of glycosylation-deficient mutant channels in surface fractions and recordings of macroscopic potassium currents mediated by these subunits demonstrate that non-glycosylated hTREK-1 channels subunits are able to reach the cell surface in general, but seemingly with reduced efficiency.

Conclusion and implications

hTREK-1 are glycoproteins and N glycosylation at positions 110 and 134 is involved in channel surface trafficking. These findings extend our view on regulation of hTREK-1 currents by posttranslational modifications and provide novel insights into how glycosylation deficiency disorders may promote arrhythmogenesis.

The sphingosine analog fingolimod (FTY720) enhances tone and contractility of rat gastric fundus smooth muscle

BACKGROUND

Sphingosine and its metabolite sphingosine phosphate (S1P) regulate a multitude of biological functions, including the contractile state of smooth. Gastrointestinal side effects have been reported in patients treated with FTY720, a sphingosine analog that is approved for the treatment of multiple sclerosis. The aim of this study was to characterize the effects of FTY720 on rat gastric fundus smooth muscle under basal conditions and during activation induced by high-K⁺ solution.

METHODS

Isometric contractions of isolated circular strips of gastric fundus smooth muscle were recorded using the organ bath method. The effects of FTY720 or vehicle were recorded under control conditions and in the presence of indomethacin, L-NAME, HA-1100, nifedipine, JTE-013, and suramin. Tone and contractions recorded in the presence of FTY720 or vehicle are reported as % of the amplitude of an initial high-K⁺ contraction obtained under control conditions.

KEY RESULTS

From a concentration of 10 μmol L^-1 onwards, FTY720 increased the tone, reaching 8.9% ± 7.5% at 100 μmol L^-1 (P < .05). With indomethacin in the solution, the effects of FTY720 were enhanced (32.1% ± 7.7%; P < .001). The FTY720-induced increase in tone was abolished in the absence of extracellular Ca²⁺ and reduced by nifedipine, HA-1100, JTE-013, and suramin. Furthermore, FTY720 increased high-K⁺ contractions in the presence of indomethacin.

CONCLUSIONS & INFERENCES

FTY720 increases tone and contractile responses to depolarization in gastric fundus smooth muscle by triggering calcium entry and calcium sensitization in a S1P receptor-dependent manner. Taken together, the experimental results presented in this work suggest that FTY720 may increase gastric tone and contractility in patients.

Mono-, di-, and trichlorinated biphenyls (PCB 1-PCB 39) in the indoor air of office rooms and their relevance on human blood burden

Exposure to polychlorinated biphenyls (PCBs) from indoor air can lead to a significant increase in lower chlorinated congeners in human blood. Lower chlorinated congeners with short biological half-lives can exhibit an indirect genotoxic potential via their highly reactive metabolites. However, little is known about their occurrence in indoor air and, therefore, about the effects of possible exposure to these congeners. We analyzed all mono-, di-, and trichlorinated biphenyls in the indoor air of 35 contaminated offices, as well as in the blood of the 35 individuals worked in these offices for a minimum of 2 years. The median concentration of total PCB in the indoor air was 479 ng/m³ . The most prevalent PCBs in the indoor air samples were the trichlorinated congeners PCB 31, PCB 18, and PCB 28, with median levels of 39, 31, and 26 ng/m³ , respectively. PCB 8 was the most prevalent dichlorinated congener (median: 9.1 ng/m³ ). Monochlorinated biphenyls were not detected in relevant concentrations. In the blood samples, the most abundant congener was PCB 28; nearly 90% of all mono-, di-, and trichlorinated congeners were attributed to this congener (median: 12 ng/g blood lipid).

Tollip SNP rs5743899 modulates human airway epithelial responses to rhinovirus infection

BACKGROUND

Rhinovirus (RV) infection in asthma induces varying degrees of airway inflammation (e.g. neutrophils), but the underlying mechanisms remain unclear.

OBJECTIVE

The major goal was to determine the role of genetic variation [e.g. single nucleotide polymorphisms (SNPs)] of Toll-interacting protein (Tollip) in airway epithelial responses to RV in a type 2 cytokine milieu.

METHODS

DNA from blood of asthmatic and normal subjects was genotyped for Tollip SNP rs5743899 AA, AG and GG genotypes. Human tracheobronchial epithelial (HTBE) cells from donors without lung disease were cultured to determine pro-inflammatory and antiviral responses to IL-13 and RV16. Tollip knockout and wild-type mice were challenged with house dust mite (HDM) and infected with RV1B to determine lung inflammation and antiviral response.

RESULTS

Asthmatic subjects carrying the AG or GG genotype (AG/GG) compared with the AA genotype demonstrated greater airflow limitation. HTBE cells with AG/GG expressed less Tollip. Upon IL-13 and RV16 treatment, cells with AG/GG (vs. AA) produced more IL-8 and expressed less antiviral genes, which was coupled with increased NF-κB activity and decreased expression of LC3, a hallmark of the autophagic pathway. Tollip co-localized and interacted with LC3. Inhibition of autophagy decreased antiviral genes in IL-13- and RV16-treated cells. Upon HDM and RV1B, Tollip knockout (vs. wild-type) mice demonstrated higher levels of lung neutrophilic inflammation and viral load, but lower levels of antiviral gene expression.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data suggest that Tollip SNP rs5743899 may predict varying airway response to RV infection in asthma.

Familial Hemiplegic Migraine—A Reappraisal and a Long-Term Follow-Up Study

Six patients (two females and four males in one family) with hemiplegic migraine are described. The age of onset was between six and eighteen years. Hemiplegic attacks were usually accompanied by transient neurological disturbances referable to the territory of the vertebrobasilar arterial tree. Brain-stem involvement and vertebrobasilar dysfunction in the reported family was supported by angiography in one case, revealing a marked and prolonged spasm of the basilar artery. Despite its dramatic character and occasionally prolonged deficits the course was essentially benign. Hemiplegic attacks disappeared during adolescence in five of the six patients. No permanent neurological residual phenomena were encountered during a mean follow-up of 14 years. The possibility is raised of a genetically determined susceptibility to periodic vasoconstriction in a particular vascular area as the basis of the syndrome.

LTRA inhibition of exercise-induced bronchoconstriction

Exercise-induced bronchoconstriction (EIB) affects between 70% and 80% of asthmatic patients. Shortly after strenuous exercise, several inflammatory mediators, including the cysteinyl leukotrienes, induce bronchoconstriction. Evidence of this phenomenon includes the increase in urinary leukotriene E4 excretion after exercise and the inhibition of EIB by the leukotriene synthesis inhibitor zileuton. Similarly, the leukotriene receptor antagonists (LTRAs) montelukast and zafirlukast have significantly reduced the decrease in pulmonary function after exercise and shortened the time to recovery. Because exercise is generally a less predictable event in children, EIB can be more difficult to manage in pediatric than in adult asthmatic patients. However, LTRA use may temper this problem. Montelukast administered once daily at bedtime protected pediatric patients against EIB throughout the entire day. Zafirlukast attenuated EIB within 4 hours of dosing in 6- to 17-year-old patients who had mild to moderate asthma. Currently, inhaled ss2-agonists are widely prescribed for EIB, but when used long term, their efficacy may wane because of tolerance. In contrast, one of the advantages offered by LTRA therapy is the absence of tolerance.

Long-lived plasma cells are generated in mucosal immune responses and contribute to the bone marrow plasma cell pool in mice

During systemic immune responses, plasma blasts are generated in secondary lymphoid organs and migrate to the bone marrow, where they can become long-lived, being responsible for the maintenance of long-term antibody titers. Plasma blasts generated in mucosal immune responses of the small intestine home to the lamina propria (LP), producing mainly immunoglobulin A. The migration of these antibody-secreting cells is well characterized during acute immune responses. Less is known about their lifetime and contribution to the long-lived bone marrow compartment. Here we investigate the lifetime of plasma cells (PCs) and the relationship between the PC compartments of the gut and bone marrow after oral immunization. Our findings indicate that PCs in the LP can survive for extended time periods. PCs specific for orally administered antigens can be detected in the bone marrow for at least 9 months after immunization, indicating that the mucosal PC compartment can contribute to the long-lived PC pool in this organ, independent of the participation of splenic B cells. Our findings suggest that the compartmentalization between mucosal and systemic PC pools is less strict than previously thought. This may have implications for the development of vaccines as well as for autoantibody-mediated diseases.

[Narrow band imaging for early diagnosis of epithelial dysplasias and microinvasive tumors in the upper aerodigestive tract]

The various stages of tumor growth are characterized by typical epithelial, vascular, and secondary connective tissue changes. Narrow band imaging (NBI) endoscopy is a minimally invasive imaging technique that presents vascular structures in particular at a higher contrast than white light endoscopy alone. In combination with high-resolution image recording and reproduction (high-definition television, HDTV; ultra-high definition, 4K), progress has been made in otolaryngological differential diagnostics, both pre- and intraoperatively. This progress represents an important step towards a so-called optical biopsy. Flexible endoscopy in combination with NBI allows detailed assessment of areas of the upper aerodigestive tract which are difficult to assess by rigid endoscopy. Papillomas, precancerous, and cancerous lesions are characterized by epithelial and connective tissue changes, as well as by typical perpendicular vascular changes. Systematic use of NBI is recommended in the differential diagnosis of malignant lesions of the upper aerodigestive tract. NBI also convinces by a significant improvement in pre- and intraoperative assessment of superficial resection margins. In particular, the combination of NBI and contact endoscopy (compact endoscopy) permits excellent therapeutic decisions during tumor surgery. Intraoperative determination of resection margins at unprecedented precision is possible. In addition, assessment of the form and extent of the perpendicular vessel loops stimulated by epithelial signaling enables differential diagnostic decisions to be made, approximating our goal of an optical biopsy.

Detecting organic materials with a CCD camera

Absorption bands in the near-infrared are used to detect materials composed of organic molecules, in scenes imaged with a conventional CCD camera. A simple model of reflectance spectra (between 850 and 980 nm) is proposed and tested on a wide range of materials. An existing vision system that was designed to detect materials with high water content is tested on organic materials. The system cannot detect materials (such as cellulose and starch) that consist of chains of sugars. It is able to robustly detect materials such as fats and aliphatic plastics (in their pure form), whose molecules are essentially long chains of CH(2) and CH(3) groups. The ability of the system to detect plastic objects is limited by inorganic additives in the plastics.

[Safe reprocessing of medical devices with a view of the entire process chain. Recommendations of the VDI 5700 guidelines]

The reprocessing of medical devices for low pathogen or sterile use is in itself potentially risky even though the aim of reprocessing is the avoidance of hygienic or technically functional risks. The methodological principles of risk management for medical devices are described in the standard DIN EN ISO 14971. The recommendations of the Commission for Hospital Hygiene and Infectious Disease Prevention (Kommission für Krankenhaushygiene und Infektionsprävention KRINKO) of the Robert Koch Institute (RKI) and the Federal Institute for Drugs and Medical Devices (Bundesinstituts für Arzneimittel und Medizinprodukte BfArM) "hygiene requirements for the reprocessing of medical devices" clarify numerous reprocessing-specific risks and are structured with reference to the different steps of reprocessing. The aim was a practical combination of the normative risk management methodology with the process-oriented KRINKO/BfArM recommendations, which has provided an interdisciplinary group of experts moderated by the Association of German Engineers (VDI). The main contents of the VDI 5700 guidelines on "hazards associated with the reprocessing--risk management in the reprocessing of medical devices--measures for risk control" and the process of the development of these guidelines is described.

Organophosphate flame retardants and plasticizers in the air and dust in German daycare centers and human biomonitoring in visiting children (LUPE 3)

Organophosphate (OP) flame retardants and plasticizers are chemicals that have been used in large quantities in diverse consumer and building-related products for decades. In the present study, OPs were measured in paired indoor air and dust samples from 63 daycare centers in Germany. Moreover, the urine of 312 children between 22 and 80 months old who attend these facilities was analyzed for the presence of eight OP metabolites. Tri-(2-butoxyethyl)-phosphate (TBEP), tris-(2-chloroisopropyl) phosphate (TCPP), and tri-n-butyl-phosphate (TnBP) were present in low concentrations in indoor air, with median values of 49 ng/m(3), 2.7 ng/m(3), and 2.2 ng/m(3), respectively. In dust, median values of 225 mg/kg for TBEP, 2.7 mg/kg for TCPP, 1.1mg/kg for diphenyl(2-ethylhexyl) phosphate, and 0.5mg/kg for tri-phenyl-phosphate (TPhP) were found. In the urine samples, the metabolites di-phenyl-phosphate, di-n-butyl-phosphate, and di-(2-butoxyethyl)-phosphate had median values (95th percentiles) of 0.8 μg/l (4.0 μg/l), 0.2 μg/l (0.9 μg/l), and 2.0 μg/l (10.7 μg/l), respectively. A significant correlation was found between the dust and air samples in the levels of TnBP, tris(2-chloroethyl) phosphate (TCEP), and TBEP. For TCEP and TBEP, significant correlations were also observed between the levels in dust and the respective metabolite levels in urine. For TCEP, there was also a significant correlation between the concentration in indoor air and metabolite levels in urine. Based on the 95th percentile in dust and air in our study and data from residences in a previously published study, the daily intake of the most abundant OP (TBEP) is high (i.e., 3.2 μg/kg b.w.). This level is approximately 6.4% of the reference dose (RfD) established by the NSF, U.S.A. Overall, our study shows that daycare centers are indoor environments that contribute to OP exposure.

Fabrication and operation of a two-dimensional ion-trap lattice on a high-voltage microchip

Microfabricated ion traps are a major advancement towards scalable quantum computing with trapped ions. The development of more versatile ion-trap designs, in which tailored arrays of ions are positioned in two dimensions above a microfabricated surface, will lead to applications in fields as varied as quantum simulation, metrology and atom-ion interactions. Current surface ion traps often have low trap depths and high heating rates, because of the size of the voltages that can be applied to them, limiting the fidelity of quantum gates. Here we report on a fabrication process that allows for the application of very high voltages to microfabricated devices in general and use this advance to fabricate a two-dimensional ion-trap lattice on a microchip. Our microfabricated architecture allows for reliable trapping of two-dimensional ion lattices, long ion lifetimes, rudimentary shuttling between lattice sites and the ability to deterministically introduce defects into the ion lattice.