Atrial fibrillation-associated electrical remodelling in human induced pluripotent stem cell-derived atrial cardiomyocytes: a novel pathway for antiarrhythmic therapy development

AIMS

Atrial fibrillation (AF) is associated with tachycardia-induced cellular electrophysiology alterations which promote AF chronification and treatment resistance. Development of novel antiarrhythmic therapies is hampered by the absence of scalable experimental human models that reflect AF-associated electrical remodelling. Therefore, we aimed to assess if AF-associated remodelling of cellular electrophysiology can be simulated in human atrial-like cardiomyocytes derived from induced pluripotent stem cells in the presence of retinoic acid (iPSC-aCM), and atrial-engineered human myocardium (aEHM) under short term (24 h) and chronic (7 days) tachypacing (TP).

METHODS AND RESULTS

First, 24-h electrical pacing at 3 Hz was used to investigate whether AF-associated remodelling in iPSC-aCM and aEHM would ensue. Compared to controls (24 h, 1 Hz pacing) TP-stimulated iPSC-aCM presented classical hallmarks of AF-associated remodelling: (i) decreased L-type Ca2+ current (ICa,L) and (ii) impaired activation of acetylcholine-activated inward-rectifier K+ current (IK,ACh). This resulted in action potential shortening and an absent response to the M-receptor agonist carbachol in both iPSC-aCM and aEHM subjected to TP. Accordingly, mRNA expression of the channel-subunit Kir3.4 was reduced. Selective IK,ACh blockade with tertiapin reduced basal inward-rectifier K+ current only in iPSC-aCM subjected to TP, thereby unmasking an agonist-independent constitutively active IK,ACh. To allow for long-term TP, we developed iPSC-aCM and aEHM expressing the light-gated ion-channel f-Chrimson. The same hallmarks of AF-associated remodelling were observed after optical-TP. In addition, continuous TP (7 days) led to (i) increased amplitude of inward-rectifier K+ current (IK1), (ii) hyperpolarization of the resting membrane potential, (iii) increased action potential-amplitude and upstroke velocity as well as (iv) reversibly impaired contractile function in aEHM.

CONCLUSIONS

Classical hallmarks of AF-associated remodelling were mimicked through TP of iPSC-aCM and aEHM. The use of the ultrafast f-Chrimson depolarizing ion channel allowed us to model the time-dependence of AF-associated remodelling in vitro for the first time. The observation of electrical remodelling with associated reversible contractile dysfunction offers a novel platform for human-centric discovery of antiarrhythmic therapies.

Development of a Wearable Human-Machine Interface to Track Forearm Rotation via an Optical Sensor

The goal of this research was to develop an intuitive wearable human-machine interface (HMI), utilizing an optical sensor. The proposed system quantifies wrist pronation and supination using an optical displacement sensor. Compared with existing systems, this HMI ensures intuitiveness by relying on direct measurement of forearm position, minimizes involved sensors, and is expected to be long-lasting. To test for feasibility, the developed HMI was implemented to control a prosthetic wrist based on forearm rotation of able-bodied subjects. Performance of optical sensor system (OSS) prosthesis control was compared to electromyography (EMG) based direct control, for six able-bodied individuals, using a clothespin relocation task. Results showed that the performance of OSS control was comparable to direct control, therefore validating the feasibility of the OSS HMI.

[Digitalization in rheumatological practice]

Digitalization in medicine is of major interest since the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. This article tries to present the induced changes and technical solutions with respect to the different parts in the patient journey. Symptom checkers, new health applications, digital appointment management etc. are described. Apart from the technical and digital possibilities, the changes in the quality of communication additionally have to be mentioned. There is an urgent need for further technical standardization including the interfaces. In many cases further studies must confirm the equivalence of digital applications in comparison to analogue techniques.

AB0494 COGNITIVE IMPAIRMENT IN AXIAL SPONDYLOARTHRITIS?

Background:

There is some evidence that neuropsychiatric changes occur in systemic lupus(1) and rheumatoid arthritis(2). However, little is known regarding a possible disease-related impairment of cognitive abilities in axial spondyloarthritis (axSpA).

Objectives:

To evaluate patients with axSpA regarding cognitive impairments.

Methods:

Patients with axSpA attending two rheumatology practices were routinely evaluated by rheumatologists and underwent a computer-based memory and attention test (MAT) (3, 4) with subscale scores ranging from 0 (worst) to 15 (best). The results of short-term memory and working memory were compared to an age-, sex- and education-matched control group of healthy subjects. Descriptive results are presented as median (IQR) for interval data and n (%) for nominal data if not stated otherwise. Two-tailed Wilcoxon signed-rank tests including Bonferroni-Holm adjustment for multiple tests were conducted to investigate the magnitude of potential differences in cognitive abilities.

Results:

101 consecutive patients were tested (Table 1). After multiple testing adjustment for two subscales, Wilcoxon signed-rank tests returned significant findings for working memory (V = 539.5, p = 0.006, |r| = 0.204) but not for short-term memory (V = 1075, p = 0.351, |r| = 0.078). Regarding the scales’ anchors, descriptive results on pairwise differences suggested axSpA patients to have working memory scores that are on average 10.7% lower compared to control participants (mean Δ= -1.64, SD Δ= 5.95).

Table 1.

Patients and disease characteristics

n%MeanSDMedian25% Quantile75% QuantileAge10110051.111.6524260Age (female)4847.552.611.75444.561Age (male)5352.549.811.5514157< 13 years formal education4746.5≥ 13 years formal education5453.5HLA B27 positive n/N64/9263.4Disease duration (years)10110013.711.712421Disease duration (female, years)4847.511.69.99417.2Disease duration (male, years)5352.515.512.915523BASDAI9291.13.71.73.82.45BASFI9190.132.42.31.24.5BASMI7574.31.92.3103ASDAS98972.30.82.31.82.8

Conclusion:

The MAT computerized testing is a feasible test and was well accepted by patients. Results regarding working memory suggest that cognitive abilities needed to accomplish everyday tasks may be impaired in axSpA patients. Further work is needed to characterise possible causes of or associations with this cognitive impairment.

References:

[1]Zabala A, Salgueiro M, Saez-Atxukarro O, Ballesteros J, Ruiz-Irastorza G, Segarra R. Cognitive Impairment in Patients With Neuropsychiatric and Non-neuropsychiatric Systemic Lupus Erythematosus: A Systematic Review and Meta-analysis. J Int Neuropsychol Soc. 2018:1-11.

[2]Vitturi BK, Nascimento BAC, Alves BR, de Campos FSC, Torigoe DY. Cognitive impairment in patients with rheumatoid arthritis. J Clin Neurosci. 2019;69:81-7.

[3]Adler G, Bektas M, Feger M, Lembach Y. [Computer-based assessment of memory and attention: evaluation of the memory and attention test (MAT)]. Psychiatr Prax. 2012;39(2):79-83.

[4]Adler G, Lembach Y. Memory and selective attention in multiple sclerosis: cross-sectional computer-based assessment in a large outpatient sample. Eur Arch Psychiatry Clin Neurosci. 2015;265(5):439-43.

Acknowledgements:

This study was funded by the RHADAR GbR (A Network of Rheumatologists), Bahnhofstr. 32, 82152 Planegg, Germany. RHADAR GbR has received a grant for this study from Novartis Pharma GmbH.

Disclosure of Interests:

Stefan Kleinert Consultant of: Novartis, Abbvie, Grant/research support from: Novartis, Praxedis Rapp: None declared., Florian Schuch Speakers bureau: Novartis, Abbvie, Gilead, Consultant of: Novartis, Abbvie, Gilead, Monika Ronneberger: None declared., Joerg Wendler Speakers bureau: Roche, Pharma, JanssenCilag, Novartis, Abbvie, Consultant of: JanssenCilag, Patrizia Sternad: None declared., Florian Popp: None declared., Peter Bartz-Bazzanella: None declared., Cay-Benedict von der Decken: None declared., Kirsten Karberg Speakers bureau: Roche, Sanofi, Abbvie, Lilly, Georg Gauler Speakers bureau: Abbvie, Gilead, Novartis, Lilly, Consultant of: Lilly, Gilead, Abbvie, Patrick Wurth Speakers bureau: Abbvie, Lilly, UCB, Medac, Susanna Spaethling-Mestekemper Speakers bureau: Abbvie, BMS, Celgene, Gilead, GSK, Hexal, Lilly, MSD, Novartis, Pfizer, Sanofi, UCB, Christoph Kuhn: None declared., Matthias Englbrecht Speakers bureau: AbbVie, Chugai, Eli Lilly, Novartis, Roche, Sanofi, Mundipharma, Paid instructor for: AbbVie, Chugai, Roche, Consultant of: AbbVie, Novartis, Roche, Sanofi, Grant/research support from: Roche, Chugai, Wolfgang Vorbrüggen: None declared., Georg Adler: None declared., Martin Welcker Speakers bureau: Abbvie, Actelion, Amgen, Biogen,BMS, Berlin Chemie, Celgene, Galapagos, Gilead, GSK, Hexal, Janssen, Medac, MSD, Mundipharma, Mylan, Novartis, Pfizer, Roche, Sanofi, SOBI, UCB, Grant/research support from: Novartis, Abbvie.

[Arterial and portal venous complications after HPB surgical procedures: Interdisciplinary management]

The surgical treatment of hepatopancreatobiliary (HPB) diseases requires complex operative procedures. Within the last decades the morbidity (36-50 %) and mortality (<5 %) of these procedures could be reduced; nonetheless, postoperative complications still occur in 41.2 % of cases. Compared with hepatobiliary procedures, pancreatic surgery shows an increased rate of complications. Postoperative bleeding has a major effect on the outcome and the incidence is 6.7 % after pancreatic surgery and 3.2 % after hepatobiliary surgery. The major causes of early postoperative hemorrhage are related to technical difficulties in surgery whereas late onset postoperative hemorrhage is linked to anastomosis insufficiency, formation of fistulae or abscesses due to vascular arrosion or formation of pseudoaneurysms. In many cases, delayed hemorrhage is preceded by a self-limiting sentinel bleeding. The treatment is dependent on the point in time, location and severity of the hemorrhage. The majority of early postoperative hemorrhages require surgical treatment. Late onset hemorrhage in hemodynamically stable patients is preferably treated by radiological interventions. After interventional hemostatic therapy 8.2 % of patients require secondary procedures. In the case of hemodynamic instability or development of sepsis, a relaparotomy is necessary. The treatment concept includes surgical or interventional remediation of the underlying cause of the hemorrhage. Other causes of postoperative morbidity and mortality are arterial and portal venous stenosis and thrombosis. Following liver resection, thrombosis of the portal vein occurs in 8.5-9.1 % and in 11.6 % following pancreatic resection with vascular involvement. Interventional surgical procedures or conservative treatment are suitable therapeutic options depending on the time of diagnosis and clinical symptoms. The risk of morbidity and mortality after HPB surgery can be reduced only in close interdisciplinary cooperation, which is particularly true for vascular complications.

Multimodality treatment of peritoneal carcinomatosis from colorectal cancer: first results of a new German centre for peritoneal surface malignancies

BACKGROUND

The presence of peritoneal carcinomatosis arising from colorectal cancer is associated with a poor prognosis. It was the purpose of this study to analyze morbidity, mortality, and survival after major cytoreductive surgery and intraperitoneal chemotherapy.

MATERIALS AND METHODS

Thirty-two patients with peritoneal carcinomatosis were operated between April 2004 and June 2006 with the aim of complete macroscopical cytoreduction. All had a primary colorectal carcinoma. Surgery in these patients was followed by hyperthermic intraperitoneal chemotherapy (HIPEC) consisting of mitomycin C and doxorubicin. Data were analyzed retrospectively.

RESULTS

Of all patients, 16 had appendix and 16 non-appendiceal colorectal carcinoma. A macroscopically complete cytoreduction was achieved in 24 patients by parietal and visceral peritonectomy procedures. All resections were combined with HIPEC. Overall morbidity was 34%. Most frequent surgical complications were intestinal obstruction (4/32), enteric fistula (2/32), pancreatitis (2/32), and bile leakage (2/32). One patient presented grade 4 renal toxicity. There was no hospital mortality. The median follow-up was 12 months. The 1-year overall survival rate is 96%. All patients after complete cytoreduction are still alive.

CONCLUSIONS

Cytoreductive surgery combined with HIPEC is associated with an acceptable morbidity and low mortality. Complete cytoreduction may improve survival, particularly in well-selected patients having a low tumor volume and no extra-abdominal metastases.

Insertion of natural intron 6a-6b into a human cDNA-derived gene therapy vector for cystic fibrosis improves plasmid stability and permits facile RNA/DNA discrimination

BACKGROUND

The gene therapy vector pCMV-CFTR containing human CFTR cDNA shows high segregational instability during growth in Escherichia coli.

METHODS

By host strain screening and optimization of fermentation, satisfactory levels of pCMV-CFTR production were achieved. However, the vector was also vulnerable to structural instability manifested by the appearance during fermentation of a more stable mutant form in which the bacterial insertion sequence IS1 had transposed into exon 7 of plasmidborne CFTR. The instability of pCMV-CFTR is attributable to transcription from an upstream cryptic promoter leading to the production of CFTR peptide fragments known to be toxic when expressed in E. coli. To address this, we inserted the 1.1 kb natural human 6a-6b intron into pCMV-CFTR.

RESULTS

The new vector pCMV-CFTR-int6ab is more stable in E. coli than either pCMV-CFTR or the IS1 mutant, grows to high cell density giving higher DNA yields and expresses CFTR appropriately in transfected cells. Thus, the intron has a stabilizing effect comparable to the IS1 insertion yet retains full functionality for gene therapy. We describe a PCR assay using primers directed to sequences flanking the intron that allows differentiation between DNA and mature mRNA. The T936C mutation present only in vector DNA has also been exploited to allow transgene CFTR to be distinguished and its dose-dependent expression to be detected in human cellular backgrounds.

CONCLUSIONS

Instability of a plasmid vector for gene therapy has been minimized by rational modification. The introduction of an intron for this purpose offers the additional advantage of providing a discriminatory RT-PCR assay.

Comparison of the recombinant Escherichia coli-produced protease domain of tissue-type plasminogen activator with alteplase, reteplase and streptokinase in a canine model of coronary artery thrombolysis

Recent in vitro studies have shown that although recombinant Escherichia coli-produced protease domain of tissue-type plasminogen activator (t-PA) has no appreciable fibrin binding and less plasminforming activity compared to the wild-type, it is nevertheless an effective fibrinolytic agent in a dynamic in vitro plasma clot lysis system. The purpose of the present study was to evaluate the pharmacological profile of the protease in a canine model of coronary artery thrombosis. The effects of a single i.v. bolus injection of 1 mg/kg protease were compared with those of alteplase, reteplase and streptokinase at clinically relevant doses and dosing regimens in eight dogs per group. The protease rapidly restored coronary blood flow at 12 +/- 1 min in all treated dogs with a significantly higher maximal coronary blood flow than in the reference groups, but was associated with short cycles of reocclusion in 4/8 animals. Overall, the coronary blood flow quality of the protease was not significantly different from that of the reference thrombolytics. Although fibrinogen was nearly completely degraded during protease treatment, the bleeding time was not significantly more prolonged than in reference groups. In conclusion, the protease domain is a rapidly acting, effective, bolus-injectable thrombolytic agent associated with a systemic lytic state and does not appear to cause significantly more bleeding than the reference thrombolytic agents.

Effect of disulfide bonds on the structure, function, and stability of the trypsin/tPA inhibitor from Erythrina caffra: site-directed mutagenesis, expression, and physiochemical characterization

Erythrina trypsin/tPA inhibitor (ETI) from the seeds of Erythrina caffra retains its native structure and inhibitory function after reducing its two disulfide bonds. In order to elucidate the specific role of these crosslinks, alanine residues were substituted for cysteines after cloning the gene in Escherichia coli. Expression of the recombinant inhibitor and the substitution mutants, C83A, CC39, 83AA, and CC132, 139AA, led to inclusion bodies. After solubilization in guanidinium-chloride (GdmCl)/dithiothreitol and oxidation in glutathione buffer, activity could be recovered at yields up to 80%. The mutant proteins exhibit full inhibitory function without detectable alterations of their native structure. However, their stability is reduced: at acid pH, where the oxidized natural inhibitor retains its native structure, the reduced wildtype protein and the mutants undergo at least partial denaturation, reflected by decreased pH ranges of stability: pH 5-7 for the reduced inhibitor, pH 2.5-8.5 for CC132, 139AA, and pH 3.5-8.5 for C83A and CC39, 83AA. Urea and GdmCl denaturation at pH 7 show hysteresis for both the oxidized inhibitor and the double mutant CC132, 139AA. In contrast, the reduced protein and the other mutants exhibit true equilibrium transitions at pH 7, with urea half-concentrations of 0.9 M and 1.9 M and GdmCl half-concentrations of 0.5 M and 1.0 M, respectively. The stability of Erythrina trypsin/tPA inhibitor follows the sequence: oxidized ETI > CC132, 139AA > CC39, 83AA and C83A > reduced ETI.

[Dealing with cancer--conversations with radiotherapy patients]

Thirty in-patients treated by radiotherapy were questioned in qualitative interviews about the information they had received from the physicians and their way to deal with the disease and the physicians. Furthermore 18 persons out of this group were accompanied continuously. The confidential relationships between the patients and the author of the study brought about spontaneous conversations showing some new aspects of the way to experience disease and therapy. Despite a poor prognosis and an initially insufficient information, the patients formulated their questions openly. Generally they desired a clearer communication. They criticized above all the lack of information and attention from the physicians. A need for confidence, frankness, and the conveyance of a justified hope was expressed. The physician's stress and resulting lack of time was complained of. During the time of accompanying which lasted several weeks, it became evident that information means a way to deal with the disease to which the patient can make his individual contribution. The majority of questions as well as emotional reactions as fear or depression came from those patients who seemed to be quiet persons.

Complete nucleotide sequence of the lipase gene from Staphylococcus hyicus cloned in Staphylococcus carnosus

The lipase gene from Staphylococcus hyicus subsp. hyicus was cloned in Staphylococcus carnosus and Escherichia coli. In both host organisms the lipase gene is expressed and the enzyme is released to the medium. The cloned DNA insert is 2.5 kb in length and DNA sequencing has revealed the location of the gene, the ribosomal binding site and the presence of a typical signal sequence. The open reading frame comprises 1923 nucleotides and gives a preprotein of 641 amino acids with a predicted Mr of 71.382. At the 3' end of the structural gene there are three consecutive stop codons and there is also a transcriptional termination signal.

[The witness in German criminal case (a contribution from the legal, psychological and psychiatrical view) (author's transl)]

The judgement of adult witnesses in particular cases, as sufficiently made clear by the described special case, is at least as necessary as a specialist's opinion of child testimony. Furthermore, it should be noted that the present modus of criminal proceedings does not allow for adequate objectivation possibilities of testimony of witnesses. Thirdly, it should be pointed out that at least for the so-called key witnesses a specialist's examination, i.e. by a psychiater and a psychologist is of great importance; it seems at least necessary that in problematic cases the specialist or the court should have the possibility to interrogate the witness to the exclusion of the public. It also seems of utmost importance to extend the judge's knowledge in the field relevant to the subject during his university education and also during his further professional instruction in order to enable him to identify problematical cases in time and decide on calling upon an adequate specialist.

Untersuchung einer Resonanz des karzinogenen Benzpyren. Studies on a Resonance of Carcinogenic Benzpyrene

The a- and p-states of 3.4-benzpyrene are calculated by use of common param eters and of a param eter set which predicts the quasi-degeneracy of these states.

The quasi-degeneracy will be represented by the breakage of pairing theorem and is to be described as a correlation effect, caused by an asymmetric potential.

An external field represents an external perturbation, introduced by interaction with the bioreceptor. The calculation shows a sensitive dependence of probability amplitudes for different configurations which participate in the quasi-degenerated resonance states. Thereby the dipole moment may quickly be changed so that excitons are produced. The resonance phenomenon may lead to the carcinogenic effect