7th Drug hypersensitivity meeting: part two

No abstract availabl

Whole-genome sequencing reveals host factors underlying critical COVID-19

Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genes—including reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)—in critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease

Imaging the Vascular Wall With Confocal Microscopy

Blood vessels are capable of continuous structural changes in response to varying conditions and functional demands. In physiological situations, these structural modifications -known as “vascular remodelling”- are adaptive and aimed to maintain a relative constant shear and wall stress. Vascular remodelling is also common to several pathological conditions, such as hypertension and atherosclerosis, where the structural changes are no longer adaptive and contribute to the progression of the disease. Vascular remodelling is a dynamic process involving cell growth, death, as well as extracellular matrix synthesis and degradation. However, knowledge of vascular remodelling has been largely based on a long-standing, static view from two-dimensional histology and the 3-dimensional (3-D) organization of the different types of vascular cells and their relationship with the extracellular matrix and innervation has not been thoroughly explored. In addition, important questions related to the active process of vascular remodelling, such as which cells undergo proliferation, apoptosis, phenotypic change or migration, are still unsolved. An integrated view of the interrelationships of the different elements of the arterial wall is made possible by fluorescence Laser Scanning Confocal microscopy (LSCM). Confocal microscopes allow obtaining serial optical sections of relatively thick specimens without the need to cut them as with conventional histology. With the aid of image analysis software, these serial sections can be further reconstructed to obtain 3-D images, where the structures of interest are localized and quantified. LSCM can be combined with pressure myography to obtain simultaneously information on vascular function and 3-D structure at near-to-physiological conditions. The vessel is firstly pressurized at physiological pressure to study vascular function and mechanics. Thereafter, it is fixed and stained with the fluorescent dyes of the structures of interest. The fixed vessel is mounted intact on a slide provided with a small well to avoid 3-D distortion and it is visualized with a LSCM. The vascular wall is scanned from the adventitial to the endothelial layer and serial optical sections are acquired with the microscope. These serial images can be processed with an image analysis software that allows for reconstruction of 3-D models and for quantification of the stained structures. There are a vast number of fluorescent compounds useful to study vessel structure. For example, fluorescent dyes that bind with DNA, such as propidium iodide, DAPI or Hoescht 3332, are useful to identify the different types of vascular cells – adventitial, smooth muscle and endothelial cells- by the shape and orientation of their nuclei. With the aid of morphometric methods, which involve segmentation and object extraction, it is possible to identify and quantify cell type, number, shape, orientation and density in the different layers of the vascular wall. The use of fluorescent antibodies and kits allows locating, within an intact vascular wall, the distribution of nerves, specific enzymes and extracellular matrix elements and to study their relationship with the vascular cells. LSCM enables to scan and process relatively large amounts of tissue in short time. This makes possible to locate rather infrequent events in the vascular wall, such as cell apoptosis or proliferation, cells undergoing phenotypic change or migration. LSCM is not only useful to image vascular wall structure, but also to visualize and quantify by the intensity of fluorescence, the generation of vascular cell products, such as nitric oxide or superoxide anion. In conclusion, confocal microscopy and image analysis software permits to image vascular wall structure and function and to assess the active process of vascular remodelling in physiological and pathological situations

Myoedothelial connection, a relationship between spiral arrangement of smooth muscle cells and endothelium in resistance muscular arteries

AbstractBackground and Purpose: Conventionally, the architecture of the artery wall is based upon the close-packed smooth muscle cells, endothelial and adventitial cells in both sides of internal elastic lamina (IEL). However, the adventitia and endothelium are now viewed as key players in vascular growth and repair. Recent work raises fundamental questions about the cellular heterogeneity of arteries, time course, triggering of normal and pathological re-modeling.Materials and Methods: Twelve wild type mice were employed. After killing with CO2 inhalation, dissected mesenteric arteries were removed and cleaned with adipose tissue. Arteries were mounted in the perfusion pressure myograph under normal pressure (70mmHg) in Kreb’s solution, which bubbled with 95% O2 and 5% CO2 to pH 7.4, at 37°C. After staining with fluorescent ligands (Syto 13) for nuclei and (DIO 1µM) for cytoplasm, arteries were scanned with the Laser Scanning Co focal Microscopy (LSCM) under (488nm/515nm), (484nm/501nm) and (543nm/580nm) Argon-Helium ion laser wavelength.Results: Three dimensional images of computer observation suggest that there may be a close relationship between the helical organization of smooth muscle cells and the underlying pattern of endothelial cells (myoendothelial connection).Conclusion: Tight junctions between cells must be broken and remade during the remodeling process. This suggests a carefully controlled defensive structure for intra-cellular connections, that is capable of withstanding the acute stresses of normal function, but which must be capable of modification to adapt to a new state, when the bio-physical conditions dictate. Endothelial mosaicism related to spiral arrangements of underlying smooth muscle cells, are associated with the functional cell connections. Taken together, these issues provide an exciting new phase in understanding the physiological modeling of the vascular wall, producing a new view of the dynamic nature of vascular structure.Key words: Myoedothelial Connections, Remodeling, Mesenteric Arteries, Internal Elastic Lamina, Fluorescent StainingJ Mazand Univ Med Sci 2008; 18(64): 60-70 (Persian

Structural and functional alterations in the basilar artery from stroke prone spontaneously hypertensive rats

No abstract available

Structural and functional alterations in the basilar artery from stroke prone spontaneously hypertensive rats

No abstract available

3-dimensional analysis of vascular structure, function & receptor distribution using confocal laser scanning microscopy

No abstract available