Guy Van Camp

Relation between patent foramen ovale and unexplained stroke

To better elucidate the possible role of the patent foramen ovale (PFO) in patients with unexplained stroke, the relation between the incidence of stroke and 3 characteristics of PFO (timing, magnitude of appearance of echocardiographic contrast in the left atrium, and morphology of the atrial septum) was analyzed. Twenty-nine patients with unexplained stroke and 28 without stroke were compared. A significant relation was only found between the incidence of cerebrovascular accident and positive contrast echocardiography in patients with early and massive passage of contrast in the left atrium (6 of 29 [21%] in the stroke group vs 0 of 28 [0%] in the control group; p < 0.05). An abnormal morphology of the foramen ovale was found more frequently in patients with PFO than in those without PFO (9 of 13 [69%] vs 1 of 44 [2%]; p < 0.001). The results suggest the use of timing and quantification of contrast appearance in the left atrium during contrast transesophageal echocardiography, and that paradoxical embolism through a PFO is a possible mechanism of cryptogenic stroke only if there is a massive passage of contrast through an abnormal foramen ovale.

Comparison of transthoracic echocardiography with second harmonic imaging with transesophageal echocardiography in the detection of right to left shunts

We compared the use of transthoracic echocardiography with second harmonic imaging after a peripheral intravenous injection of an agitated saline solution with transesophageal echocardiography (TEE) in the detection of right to left shunts at the cardiac and pulmonary level. Second harmonic mode transthoracic echocardiography and TEE are equally sensitive in detecting right to left shunts in patients undergoing a daily routine TEE.

Pharmacological levels of Withaferin A (**Withania somnifera**) trigger clinically relevant anticancer effects specific to triple negative breast cancer cells

Withaferin A (WA) isolated from Withania somnifera (Ashwagandha) has recently become an attractive phytochemical under investigation in various preclinical studies for treatment of different cancer types. In the present study, a comparative pathway-based transcriptome analysis was applied in epithelial-like MCF-7 and triple negative mesenchymal MDA-MB-231 breast cancer cells exposed to different concentrations of WA which can be detected systemically in in vivo experiments. Whereas WA treatment demonstrated attenuation of multiple cancer hallmarks, the withanolide analogue Withanone (WN) did not exert any of the described effects at comparable concentrations. Pathway enrichment analysis revealed that WA targets specific cancer processes related to cell death, cell cycle and proliferation, which could be functionally validated by flow cytometry and real-time cell proliferation assays. WA also strongly decreased MDA-MB-231 invasion as determined by single-cell collagen invasion assay. This was further supported by decreased gene expression of extracellular matrix-degrading proteases (uPA, PLAT, ADAM8), cell adhesion molecules (integrins, laminins), pro-inflammatory mediators of the metastasis-promoting tumor microenvironment (TNFSF12, IL6, ANGPTL2, CSF1R) and concomitant increased expression of the validated breast cancer metastasis suppressor gene (BRMS1). In line with the transcriptional changes, nanomolar concentrations of WA significantly decreased protein levels and corresponding activity of uPA in MDA-MB-231 cell supernatant, further supporting its anti-metastatic properties. Finally, hierarchical clustering analysis of 84 chromatin writer-reader-eraser enzymes revealed that WA treatment of invasive mesenchymal MDA-MB-231 cells reprogrammed their transcription levels more similarly towards the pattern observed in non-invasive MCF-7 cells. In conclusion, taking into account that sub-cytotoxic concentrations of WA target multiple metastatic effectors in therapy-resistant triple negative breast cancer, WA-based therapeutic strategies targeting the uPA pathway hold promise for further (pre)clinical development to defeat aggressive metastatic breast cancer.

Heterozygous Loss-of-Function SEC61A1 Mutations Cause Autosomal-Dominant Tubulo-Interstitial and Glomerulocystic Kidney Disease with Anemia.

Autosomal-dominant tubulo-interstitial kidney disease (ADTKD) encompasses a group of disorders characterized by renal tubular and interstitial abnormalities, leading to slow progressive loss of kidney function requiring dialysis and kidney transplantation. Mutations in UMOD, MUC1, and REN are responsible for many, but not all, cases of ADTKD. We report on two families with ADTKD and congenital anemia accompanied by either intrauterine growth retardation or neutropenia. Ultrasound and kidney biopsy revealed small dysplastic kidneys with cysts and tubular atrophy with secondary glomerular sclerosis, respectively. Exclusion of known ADTKD genes coupled with linkage analysis, whole-exome sequencing, and targeted re-sequencing identified heterozygous missense variants in SEC61A1—c.553A>G (p.Thr185Ala) and c.200T>G (p.Val67Gly)—both affecting functionally important and conserved residues in SEC61. Both transiently expressed SEC6A1A variants are delocalized to the Golgi, a finding confirmed in a renal biopsy from an affected individual. Suppression or CRISPR-mediated deletions of sec61al2 in zebrafish embryos induced convolution defects of the pronephric tubules but not the pronephric ducts, consistent with the tubular atrophy observed in the affected individuals. Human mRNA encoding either of the two pathogenic alleles failed to rescue this phenotype as opposed to a complete rescue by human wild-type mRNA. Taken together, these findings provide a mechanism by which mutations in SEC61A1 lead to an autosomal-dominant syndromic form of progressive chronic kidney disease. We highlight protein translocation defects across the endoplasmic reticulum membrane, the principal role of the SEC61 complex, as a contributory pathogenic mechanism for ADTKD.

First experience with real-time three-dimensional transoesophageal echocardiography-guided transseptal in patients undergoing atrial fibrillation ablation

AIMSnTransseptal (TS) puncture during atrial fibrillation (AF) ablation is a relatively safe procedure in experienced hands. However, major and minor complications cannot be completely ruled out. Real-time three-dimensional transeosophageal echocardiography (RT 3D TEE) is a novel imaging technology that permits direct visualization of the fossa ovalis in a 3D perspective, thereby sensibly lowering the likelihood of potential adverse effects during TS. In our study, we describe the technique and assess the feasibility, advantages, and safety of this novel imaging method in guiding TS puncture in a series of consecutive patients undergoing AF ablation.nnnMETHODS AND RESULTSnWe performed TS puncture guided by RT 3D TEE under general anaesthesia in 24 consecutive patients (16 male, 55.4 +/- 8.1 years) undergoing ablation for drug refractory AF. The fossa ovalis could clearly be seen and easily be distinguished from surrounding anatomical structures in all 24 patients. All punctures required a single attempt to access left atrium. Mean orientation of the needle hub when puncturing was 4.30 oclock (ranging from 3 oclock to 6.30 oclock), and mean distances from the needle tip to the aortic and to the posterior wall were, respectively, 13.5 +/- 7 and 35 +/- 7.3 mm. Total fluoroscopic time was 120.6 +/- 34 s. No major or minor complications were experienced.nnnCONCLUSIONnReal-time three-dimensional transeosophageal is a very useful tool in guiding TS puncture in patients undergoing AF ablation with the invaluable advantage of the 3D direct visualization of the fossa ovalis. This permits fast and safe transatrial access with a single puncture attempt.

Role of echocardiography in toxic heart valvulopathy

The notion that drugs can induce valvular heart disease (VHD) has occurred since the 1960s and has received a lot of attention in recent years. This review focuses on different aspects of this distinct valvulopathy in seven sections: (i) historical background, (ii) drug-induced VHD, is this a real entity?, (iii) its morphological and echocardiographic features, (iv) drugs associated with VHD, (v) the influence of cumulative drug dose and risk factors, (vi) the natural course of toxic valvulopathy, and (vii) practical recommendations when using potential valvulopathic drugs.

Targeting of vascular cell adhesion molecule-1 by 18F-labelled nanobodies for PET/CT imaging of inflamed atherosclerotic plaques

AIMSnPositron emission tomography-computed tomography (PET-CT) is a highly sensitive clinical molecular imaging modality to study atherosclerotic plaque biology. Therefore, we sought to develop a new PET tracer, targeting vascular cell adhesion molecule (VCAM)-1 and validate it in a murine atherosclerotic model as a potential agent to detect atherosclerotic plaque inflammation.nnnMETHODS AND RESULTSnThe anti-VCAM-1 nanobody (Nb) (cAbVCAM-1-5) was radiolabelled with Fluorine-18 ((18)F), with a radiochemical purity of >98%. In vitro cell-binding studies showed specific binding of the tracer to VCAM-1 expressing cells. In vivo PET/CT imaging of ApoE(-/-) mice fed a Western diet or control mice was performed at 2h30 post-injection of [(18)F]-FB-cAbVCAM-1-5 or (18)F-control Nb. Additionally, plaque uptake in different aorta segments was evaluated ex vivo based on extent of atherosclerosis. Atherosclerotic lesions in the aortic arch of ApoE(-/-) mice, injected with [(18)F]-FB-anti-VCAM-1 Nb, were successfully identified using PET/CT imaging, while background signal was observed in the control groups.xa0These results were confirmed by ex vivo analyses where uptake of [(18)F]-FB-cAbVCAM-1-5 in atherosclerotic lesionsxa0was significantly higher compared with control groups. Moreover, uptake increased with the increasing extent of atherosclerosis (Score 0: 0.68 ± 0.10, Score 1: 1.18 ± 0.36, Score 2: 1.49 ± 0.37, Score 3: 1.48 ± 0.38%ID/g, Spearmans r(2) = 0.675, P < 0.0001).xa0Highxa0lesion-to-heart, lesion-to-blood, and lesion-to-control vessel ratios were obtained (12.4 ± 0.4, 3.3 ± 0.4, and 3.1 ± 0.6, respectively).nnnCONCLUSIONnThe [(18)F]-FB-anti-VCAM-1 Nb, cross-reactive for both mouse and human VCAM-1, allows non-invasive PET/CT imaging of VCAM-1 expression in atherosclerotic plaques in a murine model and may represent an attractive tool for imaging vulnerable atherosclerotic plaques in patients.

Dose Dependency and Reversibility of Serotonin-Induced Valvular Heart Disease in Rats

Serotonergic drugs may lead to valvular heart disease in humans and more recently also in rats. Although clinical data suggest that dose dependency and reversibility after drug cessation might occur, proof of this is lacking. For that purpose, a total of 106 rats were prospectively enrolled: 22 control animals and 7 groups of 12 rats that received daily subcutaneous serotonin injections (5, 10, 20, 30, 40, 50 and 60xa0mg/kg respectively) for 12xa0weeks. At 12xa0weeks, half of the animals of each group were killed for histological analysis, whereas the remaining rats were further followed (without serotonin injections) for an additional 8xa0weeks. After 12xa0weeks of serotonin treatment, aortic and mitral regurgitation (AR, MR) were more frequently observed in the high dose groups (>30xa0mg/kg) compared to controls. Moreover, aortic and mitral valves were also thicker in the high dose groups compared to controls. After 8xa0weeks free of serotonin injections, AR and MR were no longer significantly higher than controls. Moreover, aortic and mitral valve thickness had normalized, returning to control levels. In conclusion, this study provides evidence for a dose-dependent valvular toxicity of serotonergic drugs, which appears to be reversible after drug withdrawal.

Intracardiac Thrombi Associated with Antiphospholipid Antibodies

Two cases of intracardiac thrombi associated with antiphospholipid antibodies are presented, one in the right atrium and the other in the left ventricle, the latter occurring in the presence of normal left ventricular function. In each, the diagnosis was made by transthoracic echocardiography. Both patients had contraindications to thrombolytic therapy and underwent successful surgical thrombectomy. We suggest that serial transthoracic echocardiography may be warranted in the follow-up of patients with primary hypercoagulable states.

DNA Diagnostics of Hereditary Hearing Loss: A Targeted Resequencing Approach Combined with a Mutation Classification System

Although there are nearly 100 different causative genes identified for nonsyndromic hearing loss (NSHL), Sanger sequencing‐based DNA diagnostics usually only analyses three, namely, GJB2, SLC26A4, and OTOF. As this is seen as inadequate, there is a need for high‐throughput diagnostic methods to detect disease‐causing variations, including single‐nucleotide variations (SNVs), insertions/deletions (Indels), and copy‐number variations (CNVs). In this study, a targeted resequencing panel for hearing loss was developed including 79 genes for NSHL and selected forms of syndromic hearing loss. One‐hundred thirty one presumed autosomal‐recessive NSHL (arNSHL) patients of Western‐European ethnicity were analyzed for SNVs, Indels, and CNVs. In addition, we established a straightforward variant classification system to deal with the large number of variants encountered. We estimate that combining prescreening of GJB2 with our panel leads to a diagnosis in 25%–30% of patients. Our data show that after GJB2, the most commonly mutated genes in a Western‐European population are TMC1, MYO15A, and MYO7A (3.1%). CNV analysis resulted in the identification of causative variants in two patients in OTOA and STRC. One of the major challenges for diagnostic gene panels is assigning pathogenicity for variants. A collaborative database collecting all identified variants from multiple centers could be a valuable resource for hearing loss diagnostics.