Reconstitution of a functional human thymus by postnatal stromal progenitor cells and natural whole-organ scaffolds.

The thymus is a primary lymphoid organ, essential for T cell maturation and selection. There has been long-standing interest in processes underpinning thymus generation and the potential to manipulate it clinically, because alterations of thymus development or function can result in severe immunodeficiency and autoimmunity. Here, we identify epithelial-mesenchymal hybrid cells, capable of long-term expansion in vitro, and able to reconstitute an anatomic phenocopy of the native thymus, when combined with thymic interstitial cells and a natural decellularised extracellular matrix (ECM) obtained by whole thymus perfusion. This anatomical human thymus reconstruction is functional, as judged by its capacity to support mature T cell development in vivo after transplantation into humanised immunodeficient mice. These findings establish a basis for dissecting the cellular and molecular crosstalk between stroma, ECM and thymocytes, and offer practical prospects for treating congenital and acquired immunological diseases.

Latest developments in post-mortem foetal imaging.

A sustained decline in parental consent rates for perinatal autopsies has driven the development of less-invasive methods for death investigation. A wide variety of imaging modalities have been developed for this purpose and include post-mortem whole body magnetic resonance imaging (MRI), ultrasound, computed tomography (CT) and micro-focus CT techniques. These are also vital for "minimally invasive" methods, which include potential for tissue sampling, such as image guidance for targeted biopsies and laparoscopic-assisted techniques. In this article, we address the range of imaging techniques currently in clinical practice and those under development. Significant advances in high-field MRI and micro-focus CT imaging show particular promise for smaller and earlier gestation foetuses. We also review how MRI biomarkers such as diffusion-weighted imaging and organ volumetric analysis may aid diagnosis and image interpretation in the absence of autopsy data. Three-dimensional printing and augmented reality may help make imaging findings more accessible to parents, colleagues and trainees.

Minimally invasive autopsy for fetuses and children based on a combination of post-mortem MRI and endoscopic examination: a feasibility study.

BACKGROUND: Less invasive perinatal and paediatric autopsy methods, such as imaging alongside targeted endoscopy and organ biopsy, may address declining consent rates for traditional autopsy, but their acceptability and accuracy are not known. OBJECTIVES: The aims of this study were to provide empirical data on the acceptability and likely uptake for different types of autopsy among key stakeholders (study 1); and to analyse existing autopsy data sources to provide estimates of the potential efficacy of less invasive autopsy (LIA) and its projected utility in clinical practice (study 2). REVIEW METHODS: Study 1: this was a mixed-methods study. Parents were involved in research design and interpretation of findings. Substudy 1: a cross-sectional survey of 859 parents who had experienced miscarriage, termination of pregnancy for fetal anomaly, stillbirth, infant or child death, and interviews with 20 responders. Substudy 2: interviews with 25 health professionals and four coroners. Substudy 3: interviews with 16 religious leaders and eight focus groups, with 76 members of the Muslim and Jewish community. Study 2: a retrospective analysis of national data in addition to detailed information from an existing in-house autopsy database of > 5000 clinical cases that had undergone standard autopsy to determine the proportion of cases by clinical indication group for which tissue sampling of specific internal organs significantly contributed to the diagnosis. RESULTS: Substudy 1: 91% of participants indicated that they would consent to some form of LIA, 54% would consent to standard autopsy, 74% to minimally invasive autopsy (MIA) and 77% to non-invasive autopsy (NIA). Substudy 2: participants viewed LIA as a positive development, but had concerns around the limitations of the technology and de-skilling the workforce. Cost implications, skills and training requirements were identified as implementation challenges. Substudy 3: religious leaders agreed that NIA was religiously permissible, but MIA was considered less acceptable. Community members indicated that they might consent to NIA if the body could be returned for burial within 24 hours. Study 2: in 5-10% of cases of sudden unexplained death in childhood and sudden unexplained death in infants, the final cause of death is determined by routine histological sampling of macroscopically normal organs, predominantly the heart and lungs, and in this group routine histological sampling therefore remains an important aspect of investigation. In contrast, routine histological examination of macroscopically normal organs rarely (< 0.5%) provides the cause of death in fetal cases, making LIA and NIA approaches potentially highly applicable. LIMITATIONS: A key limitation of the empirical research is that it is hypothetical. Further research is required to determine actual uptake. Furthermore, because of the retrospective nature of the autopsy data set, findings regarding the likely contribution of organ sampling to final diagnosis are based on extrapolation of findings from historical autopsies, and prospective data collection is required to validate the conclusions. CONCLUSIONS: LIA is viable and acceptable (except for unexplained deaths), and likely to increase uptake. Further health economic, performance and implementation studies are required to determine the optimal service configuration required to offer this as routine clinical care. FUNDING: The National Institute for Health Research Health Technology Assessment programme.

Autopsy (post-mortem) examination of babies and children who die is often necessary to help doctors or coroners find out the cause of death. It may also be useful for research. However, many bereaved parents dislike the idea of their child being cut and some religious communities prohibit the procedure. Over the past 30 years, consent rates for autopsies have declined. In order to address parental concerns and declining uptake, a number of less invasive options have been developed. These include X-ray and magnetic resonance imaging, by doing keyhole internal examination and needle organ biopsy. However, it is not known to what extent such methods are acceptable to parents, nor how accurate they are. We surveyed the attitudes of bereaved parents and religious group leaders to such less invasive methods. The less invasive option was considered acceptable and would be chosen by almost 1000 bereaved parents. Such an approach is also acceptable to those religious groups for whom standard autopsy examination is not. We also examined a database of > 5000 standard autopsies to determine the extent to which specific internal organ biopsy contributed to the diagnosis. In > 5000 standard autopsies, traditional organ biopsy rarely contributed to determination of the cause of death or the main diagnosis. Therefore, a more limited and targeted tissue sampling protocol could be introduced without significant reduction in the accuracy of final diagnosis. The specific approaches required will depend on individual circumstances and are likely to include a range, from targeted organ biopsy with an open incision, through incisionless image-guided needle biopsies, to non-invasive imaging-only techniques. Future studies may focus on how the NHS could implement offering less invasive approaches nationally, what the cost­benefit of such an approach could be and what the impact could be on real-world uptake if this were to be offered routinely.