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This corrects the article DOI: 10.1038/nature19356.

Exact three-dimensional (3D) structural information of developing organoids is key for optimising organoid generation and for studying experimental outcomes in organoid models. We set up a 3D imaging technique and studied complexly arranged native and experimentally challenged cardioids of two stages of remodelling. The imaging technique we employed is S-HREM (Scanning High Resolution Episcopic Microscopy), a variant of HREM, which captures multiple images of subsequently exposed surfaces of resin blocks and automatically combines them to large sized digital volume data of voxels sizes below 1 μm3. We provide precise volumetric information of the examined specimens and their single components and comparisons between stages in terms of volume and micro- and macroanatomic structure. We describe the 3D arrangement and lining of different types of cavities and their changes between day 10 and day 14 and map the various cell types to their precise spatial and structural environment. Exemplarily, we conducted semiautomatic counts of nuclei. In cryo-injured cardioids, we examined the extension and composition of the injured areas. Our results demonstrate the high quality and the great potential of digital volume data produced with S-HREM. It also provides sound metric and structural information, which assists production of native and experimentally challenged left ventricle cardioids and interpretation of their structural remodelling. [ABSTRACT FROM AUTHOR]

Approximately one-third of all mammalian genes are essential for life. Phenotypes resulting from knockouts of these genes in mice have provided tremendous insight into gene function and congenital disorders. As part of the International Mouse Phenotyping Consortium effort to generate and phenotypically characterize 5,000 knockout mouse lines, here we identify 410 lethal genes during the production of the first 1,751 unique gene knockouts. Using a standardized phenotyping platform that incorporates high-resolution 3D imaging, we identify phenotypes at multiple time points for previously uncharacterized genes and additional phenotypes for genes with previously reported mutant phenotypes. Unexpectedly, our analysis reveals that incomplete penetrance and variable expressivity are common even on a defined genetic background. In addition, we show that human disease genes are enriched for essential genes, thus providing a dataset that facilitates the prioritization and validation of mutations identified in clinical sequencing efforts.

Brillouin light scattering (BLS) spectroscopy is a label-free method of measuring the GHz-frequency viscoelastic properties. The measured longitudinal modulus is acutely sensitive to the degree of hydration, crosslinking, and temperature, which can be indicative of tissue health. As such, performing in situ measurements on humans is particularly desirable for exploring potential clinical translation, however, is not possible with existing designs which are coupled to bench-top microscopes. Here we introduce a robust fiber coupled hand-held BLS probe and demonstrate its reliability for measuring excised human tissue. We verify its accuracy using confocal BLS microscopy and further show that it is possible to distinguish veins, arteries, nerves and muscles based on their BLS-measured viscoelasticity. This provides a necessary first step towards in situ clinical BLS viscoelasticity studies of human tissue.

Large-scale phenotyping efforts have demonstrated that approximately 2530% of mouse gene knockouts cause intrauterine lethality. Analysis of these mutants has largely focused on the embryo and not the placenta, despite the crucial role of this extraembryonic organ for developmental progression. Here we screened 103 embryonic lethal and sub-viable mouse knockout lines from the Deciphering the Mechanisms of Developmental Disorders program for placental phenotypes. We found that 68% of knockout lines that are lethal at or after mid-gestation exhibited placental dysmorphologies. Early lethality (embryonic days 9.514.5) is almost always associated with severe placental malformations. Placental defects correlate strongly with abnormal brain, heart and vascular development. Analysis of mutant trophoblast stem cells and conditional knockouts suggests that a considerable number of factors that cause embryonic lethality when ablated have primary gene function in trophoblast cells. Our data highlight the hugely under-appreciated importance of placental defects in contributing to abnormal embryo development and suggest key molecular nodes that govern placenta formation., Author(s): Vicente Perez-Garcia [1, 2]; Elena Fineberg [1, 2]; Robert Wilson [3]; Alexander Murray [1, 2]; Cecilia Icoresi Mazzeo [4]; Catherine Tudor [4]; Arnold Sienerth [1, 2]; Jacqueline K. White [...]

We have used serial histological sections to document heart formation in Xenopus Laevis, from the formation of a linear heart tube to the appearance of morphologically distinct atrial and ventricular chambers. 3D reconstruction techniques have been used to derive accurate models from digital images, revealing the morphological changes that accompany heart differentiation. To demonstrate the utility of this approach in analysing cardiac gene expression, we have reexamined the distribution of Hand1 transcripts in the linear and lopped heart tube. Our results demonstrate that prior to looping, an initial asymmetric, left-sided pattern is replaced by more symmetrical localisation of transcripts to the ventral portion of the myocardium. After the onset of looping, Hand1 expression is restricted to the ventral ventricular myocardium and extends along the entire length of the single ventricle.

Approximately one‐third of randomly produced knockout mouse lines produce homozygous offspring, which fail to survive the perinatal period. The majority of these die around or after embryonic day (E)14.5, presumably from cardiovascular insufficiency. For diagnosing structural abnormalities underlying death and diseases and for researching gene function, the phenotype of these individuals has to be analysed. This makes the creation of reference data, which define normal anatomy and normal variations the highest priority. While such data do exist for the heart and arteries, they are still missing for the venous system. Here we provide high‐quality descriptive and metric information on the normal anatomy of the venous system of E14.5 embryos. Using high‐resolution digital volume data and 3D models from 206 genetically normal embryos, bred on the C57BL/6N background, we present precise descriptive and metric information of the venous system as it presents itself in each of the six developmental stages of E14.5. The resulting data shed new light on the maturation and remodelling of the venous system at transition of embryo to foetal life and provide a reference that can be used for detecting venous abnormalities in mutants. To explore this capacity, we analysed the venous phenotype of embryos from 7 knockout lines (Atp11a, Morc2a, 1700067K01Rik, B9d2, Oaz1, Celf4 and Coro1c). Careful comparisons enabled the diagnosis of not only simple malformations, such as dual inferior vena cava, but also complex and subtle abnormalities, which would have escaped diagnosis in the absence of detailed, stage‐specific referenced data. [ABSTRACT FROM AUTHOR]

OBJECTIVES Open in new tab Download slide Open in new tab Download slide The anatomical distribution pattern of epidural intraspinal arteries is not entirely understood but is likely to substantially impact maintaining perfusion during segmental artery sacrifice when treating acute and chronic thoraco-abdominal aortic diseases. We investigated the anatomical distribution pattern of intraspinal arteries. METHODS Twenty fresh, non-embalmed cadaveric human bodies were studied. Anatomical dissection and investigation of the epidural arterial network were performed according to a standardized protocol. We used a generalized mixed linear model to test whether the presence probability for certain vessels differed between vertebrae/segments. RESULTS There was craniocaudal continuity of all ipsilateral longitudinal connections from T1 to L5 by the anterior radicular artery. The mean [±standard deviation (SD)] number of transverse anastomoses was 9.7 ± 2.1. The presence probability of transverse anastomoses along the spine was different between vertebrae (P  < 0.0001). There were 2 distribution peaks along the spine: 1 peak around T4–T6 and 1 around T11. The mean (±SD) number of thoracic and lumbar anterior radiculomedullary arteries (ARMAs) was 3.0 ± 1.1. The probability of the presence of ARMAs along the spine was different for each vertebral segment (P  < 0.0001). Between ARMAs there were gaps of up to a maximum of 9 vertebrae. All Adamkiewicz arteries were located caudally to T7. The median segment of the Adamkiewicz presence was T10/11. CONCLUSIONS The epidural collateral network shows craniocaudal continuity. The number of transverse anastomoses is high. The number of ARMAs is low, and there is considerable variation in their distribution and offspring, which is highly likely to impact perfusion during segmental artery sacrifice when treating thoraco-abdominal aortic disease. [ABSTRACT FROM AUTHOR]