Single-cell atlas of the human brain vasculature across development, adulthood and disease.

A broad range of brain pathologies critically relies on the vasculature, and cerebrovascular disease is a leading cause of death worldwide. However, the cellular and molecular architecture of the human brain vasculature remains incompletely understood1. Here we performed single-cell RNA sequencing analysis of 606,380 freshly isolated endothelial cells, perivascular cells and other tissue-derived cells from 117 samples, from 68 human fetuses and adult patients to construct a molecular atlas of the developing fetal, adult control and diseased human brain vasculature. We identify extensive molecular heterogeneity of the vasculature of healthy fetal and adult human brains and across five vascular-dependent central nervous system (CNS) pathologies, including brain tumours and brain vascular malformations. We identify alteration of arteriovenous differentiation and reactivated fetal as well as conserved dysregulated genes and pathways in the diseased vasculature. Pathological endothelial cells display a loss of CNS-specific properties and reveal an upregulation of MHC class II molecules, indicating atypical features of CNS endothelial cells. Cell-cell interaction analyses predict substantial endothelial-to-perivascular cell ligand-receptor cross-talk, including immune-related and angiogenic pathways, thereby revealing a central role for the endothelium within brain neurovascular unit signalling networks. Our single-cell brain atlas provides insights into the molecular architecture and heterogeneity of the developing, adult/control and diseased human brain vasculature and serves as a powerful reference for future studies.

Benchmarking the CoW with the TopCoW Challenge: Topology-Aware Anatomical Segmentation of the Circle of Willis for CTA and MRA.

The Circle of Willis (CoW) is an important network of arteries connecting major circulations of the brain. Its vascular architecture is believed to affect the risk, severity, and clinical outcome of serious neuro-vascular diseases. However, characterizing the highly variable CoW anatomy is still a manual and time-consuming expert task. The CoW is usually imaged by two angiographic imaging modalities, magnetic resonance angiography (MRA) and computed tomography angiography (CTA), but there exist limited public datasets with annotations on CoW anatomy, especially for CTA. Therefore we organized the TopCoW Challenge in 2023 with the release of an annotated CoW dataset. The TopCoW dataset was the first public dataset with voxel-level annotations for thirteen possible CoW vessel components, enabled by virtual-reality (VR) technology. It was also the first large dataset with paired MRA and CTA from the same patients. TopCoW challenge formalized the CoW characterization problem as a multiclass anatomical segmentation task with an emphasis on topological metrics. We invited submissions worldwide for the CoW segmentation task, which attracted over 140 registered participants from four continents. The top performing teams managed to segment many CoW components to Dice scores around 90%, but with lower scores for communicating arteries and rare variants. There were also topological mistakes for predictions with high Dice scores. Additional topological analysis revealed further areas for improvement in detecting certain CoW components and matching CoW variant topology accurately. TopCoW represented a first attempt at benchmarking the CoW anatomical segmentation task for MRA and CTA, both morphologically and topologically.

Shaping the brain vasculature in development and disease in the single-cell era.

The CNS critically relies on the formation and proper function of its vasculature during development, adult homeostasis and disease. Angiogenesis - the formation of new blood vessels - is highly active during brain development, enters almost complete quiescence in the healthy adult brain and is reactivated in vascular-dependent brain pathologies such as brain vascular malformations and brain tumours. Despite major advances in the understanding of the cellular and molecular mechanisms driving angiogenesis in peripheral tissues, developmental signalling pathways orchestrating angiogenic processes in the healthy and the diseased CNS remain incompletely understood. Molecular signalling pathways of the 'neurovascular link' defining common mechanisms of nerve and vessel wiring have emerged as crucial regulators of peripheral vascular growth, but their relevance for angiogenesis in brain development and disease remains largely unexplored. Here we review the current knowledge of general and CNS-specific mechanisms of angiogenesis during brain development and in brain vascular malformations and brain tumours, including how key molecular signalling pathways are reactivated in vascular-dependent diseases. We also discuss how these topics can be studied in the single-cell multi-omics era.

Hierarchical imaging and computational analysis of three-dimensional vascular network architecture in the entire postnatal and adult mouse brain.

The formation of new blood vessels and the establishment of vascular networks are crucial during brain development, in the adult healthy brain, as well as in various diseases of the central nervous system. Here, we describe a step-by-step protocol for our recently developed method that enables hierarchical imaging and computational analysis of vascular networks in postnatal and adult mouse brains. The different stages of the procedure include resin-based vascular corrosion casting, scanning electron microscopy, synchrotron radiation and desktop microcomputed tomography imaging, and computational network analysis. Combining these methods enables detailed visualization and quantification of the 3D brain vasculature. Network features such as vascular volume fraction, branch point density, vessel diameter, length, tortuosity and directionality as well as extravascular distance can be obtained at any developmental stage from the early postnatal to the adult brain. This approach can be used to provide a detailed morphological atlas of the entire mouse brain vasculature at both the postnatal and the adult stage of development. Our protocol allows the characterization of brain vascular networks separately for capillaries and noncapillaries. The entire protocol, from mouse perfusion to vessel network analysis, takes ~10 d.

GAT-1 (rs2697153) and GAT-3 (rs2272400) polymorphisms are associated with febrile seizures and temporal lobe epilepsy.

The purpose of this study was to determine a possible association between two GABA transporter (GAT) single-nucleotide polymorphisms (SNPs), rs2697153 G>A in SLC6A1 (GAT-1) and rs2272400 C>T in SLC6A11 (GAT-3), and drug-resistant temporal lobe epilepsy (TLE). DNA was isolated from 138 TLE patients (from the neocortex) and 94 non-epileptic controls (from blood/buccal swaps), and amplified by polymerase chain reaction and subjected to restriction fragment length polymorphism assays. A subgroup of patients with a positive history of febrile seizures (FS+) and traumatic brain injury (TBI+) were investigated in a separate analysis. P values were obtained using the Chi-Square test and Fishers exact test. The GAT-1 SNP was different between patients and controls (p<0.05); the AA genotype was observed in 40% of the cases vs 23% of the controls (p<0.05). Thirty-one patients were FS+ and the GAT-3 CT genotype was observed significantly more frequently in the FS+ group (14%) than in the FS- group (1%; p<0.01). Thirteen patients were TBI+, and genotyping for GAT-1 and GAT-3 in these patients did not result in statistical differences between TBI+ and TBI- groups. The findings suggest that TLE is associated with GAT-1 and GAT-3 SNPs. More specifically, GAT-3 c1572T seems to be associated with TLE in patients with FS+. However, the pathophysiological consequences of these SNPs remain to be elucidated.

Editor's Choice - Open Thoracic and Thoraco-abdominal Aortic Repair in Patients with Connective Tissue Disease.

OBJECTIVE/BACKGROUND: The aim is to present current results of open complex aortic repair in patients with connective tissue disease (CTD). METHODS: This was a retrospective cross-border, single centre study. From February 2000 to April 2016 72 aortic operations were performed on 65 patients with CTD (41 male, median age 41 years [range 19-70 years]). Fifty-six patients (86%) underwent at least one previous aortic repair (71 open, four endovascular), including 33 patients (51%) operated before at the site of the procedure reported here. The open procedures, counting eight emergency operations (11%), included aortic arch revision (n = 1; 1%), descending thoracic aortic repair (n = 11; 15%), TAAA type I repair (n = 12; 17%), type II repair (n = 29; 40%), type III repair (n = 12; 17%), and type IV repair (n = 5; 7%). Simultaneous repair of the ascending aorta and/or the aortic arch was performed in two (3%) and eight cases (11%), respectively. Seven patients (10%) underwent staged procedures. Median follow-up was 42 months (0.5-180 months). RESULTS: The in hospital mortality was 14% (n = 9) as a result of haemorrhage (n = 3/9), neurological (n = 3/9), cardiac (n = 2/9), and pulmonary (n = 1/9) complications. Paraplegia and paraparesis occurred in one (2%) and three patients (5%), respectively. Seven patients (11%) required temporary dialysis; none needed permanent dialysis. Major complications were revision surgery for bleeding or haematoma (n = 20/65), sepsis (n = 10/65), myocardial infarction/severe cardiac arrhythmia (n = 2/65), stroke (n = 2/65), as well as multiorgan failure, abdominal compartment syndrome, mesenteric and peripheral ischaemia (all n = 1/65). Multivariate analysis identified an operating time > 7 hours (p = .006) as an independent predictor of increased mortality. Freedom from re-intervention was 85%, 1 year survival was 80%, and overall survival was 75%. CONCLUSION: Open TAA(A) repair is a durable therapy for patients with CTD. Often being performed as revision surgery, it can be associated with relevant risks and should therefore be reserved for specialised centres. Staged procedures and thus reducing operating time, if applicable, should be preferred.

Experiences and preferences of patients visiting a head and neck oncology outpatient clinic: a qualitative study.

The objective of this study is to report on an in-depth evaluation of patient experiences and preferences at a Head and Neck Oncology outpatient clinic. A qualitative research design was used to determine the experiences and preferences of Head and Neck Cancer patients in an Oncology Outpatient Clinic, Maastricht University Medical Center, The Netherlands. Head and Neck Cancer Patients, treated for at least 6 months at the Oncology Clinic, were included. A qualitative research design with patient interviews was used. All interviews were recorded and transcribed verbatim to increase validity. Analysis was done with use of the template approach and qualitative data analysis software. Three of the six dimensions predominated in the interview: (1) respect for patients' values, preferences and expressed need, (2) information, communication and education and (3) involvement of family and friends. The dimensions physical comfort; emotional support; coordination and integration of care were considered to be of less significance. The findings from this study resulted in a deeper understanding of patients' experiences and preferences and can be useful in the transition towards a more patient-centered approach of health care.

Experiences and preferences of patients visiting an otorhinolaryngology outpatient clinic: a qualitative study.

BACKGROUND: Patient-centred care has received considerable attention in the last few decades, but the patients' perspective remains underexposed. This study reports on an in-depth evaluation of patients' experiences and preferences at an otorhinolaryngology outpatient department. METHODS: Qualitative research was conducted on patients' experiences and preferences at an otorhinolaryngology outpatient department in an academic hospital. The study comprised two phases. First, semi-structured interviews were held with 22 patients. Second, results from the interviews were verified and deepened in a focus group (N = 7). RESULTS: Overall, experience with patient-centred care was positive at the outpatient department. Three of the six dimensions of patient-centred care predominated in the interviews and the focus group: information, communication and education; coordination and integration of care; and respect for patients' values, preferences and expressed needs. The negative experiences were mostly in these dimensions. The dimensions physical comfort and involvement of family and friends were of lesser significance. Opinion on emotional support--relieving fear and anxiety differed as to whether this was the responsibility of the doctor or the patient. CONCLUSION: Qualitative research provided a deeper understanding of patients' experiences and preferences at an otorhinolaryngology outpatient department. Such an in-depth evaluation can be useful in the transition towards patient-centred care.