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Several histopathological features are found more frequently in placentas from pregnancies complicated by fetal growth restriction (FGR), including villous infarction, maternal vascular changes and villous morphological alterations, although around one quarter of placentas associated with FGR lack any morphological abnormality on routine examination. Since similar changes may also affect clinically uncomplicated pregnancies, the positive predictive value of such findings for pathological FGR in an unselected case remains low. However, the pattern of placental pathologies varies with clinical subgroup. The combination of placental bed and parenchymal lesions in FGR with abnormal uterine artery Doppler velocimetry is essentially identical to preterm pre-eclampsia (PET), and there is an association between FGR with abnormal umbilical artery Doppler findings and lesions of fetal stem arteries and terminal villous hypovascularity. Conversely, placentas from pregnancies complicated by PET or FGR presenting at or near term have a significantly lower frequency of histological abnormalities compared to early-onset disease and absence of a distinctive biochemical profile. The histological placental findings in FGR are therefore varied, from morphologically unremarkable through to severe uteroplacental vasculopathy, with no single pathological feature associated with high sensitivity or specificity. Severe early-onset FGR, overlapping with severe early-onset PET, is mainly associated with features of impaired maternal uteroplacental perfusion secondary to defective extravillous trophoblast invasion, and its consequences. Late-onset FGR probably represents a more heterogeneous group with less characteristic histological changes. Future research using histopathological assessment of aggregated data from multiple studies into larger datasets with centralised pathology review will allow delineation of distinctive clinicopathological associations and further understanding of pathophysiology.

Senescent cells accumulate in human tissues during ageing and contribute to age-related pathologies. The mechanisms responsible for their accumulation are unclear. Here we show that senescent dermal fibroblasts express the non-classical MHC molecule HLA-E, which interacts with the inhibitory receptor NKG2A expressed by NK and highly differentiated CD8 + T cells to inhibit immune responses against senescent cells. HLA-E expression is induced by senescence-associated secretary phenotype-related pro-inflammatory cytokines, and is regulated by p38 MAP kinase signalling in vitro. Consistently, HLA-E expression is increased on senescent cells in human skin sections from old individuals, when compared with those from young, and in human melanocytic nevi relative to normal skin. Lastly, blocking the interaction between HLA-E and NKG2A boosts immune responses against senescent cells in vitro. We thus propose that increased HLA-E expression contributes to persistence of senescent cells in tissues, thereby suggesting a new strategy for eliminating senescent cells during ageing. Senescent cells increase with ageing and may cause inflammatory conditions, but how this accumulation is mediated is still unclear. Here the authors show that senescent cells express HLA-E to suppress NKG2A-mediated natural killer and CD8 T cell activation to avoid targeted elimination, while blocking NKG2A helps promote immunity against senescent cells.

Artificial intelligence as a medical device is increasingly being applied to healthcare for diagnosis, risk stratification and resource allocation. However, a growing body of evidence has highlighted the risk of algorithmic bias, which may perpetuate existing health inequity. This problem arises in part because of systemic inequalities in dataset curation, unequal opportunity to participate in research and inequalities of access. This study aims to explore existing standards, frameworks and best practices for ensuring adequate data diversity in health datasets. Exploring the body of existing literature and expert views is an important step towards the development of consensus-based guidelines. The study comprises two parts: a systematic review of existing standards, frameworks and best practices for healthcare datasets; and a survey and thematic analysis of stakeholder views of bias, health equity and best practices for artificial intelligence as a medical device. We found that the need for dataset diversity was well described in literature, and experts generally favored the development of a robust set of guidelines, but there were mixed views about how these could be implemented practically. The outputs of this study will be used to inform the development of standards for transparency of data diversity in health datasets (the STANDING Together initiative). A systematic review, combined with a stakeholder survey, presents an overview of current practices and recommendations for dataset curation in health, with specific focuses on data diversity and artificial intelligence-based applications.

Progesterone administration has been shown to reduce the risk of preterm birth and neonatal morbidity in women at high risk, but there is uncertainty about longer term effects on the child. We did a double-blind, randomised, placebo-controlled trial of vaginal progesterone, 200 mg daily taken from 22–24 to 34 weeks of gestation, on pregnancy and infant outcomes in women at risk of preterm birth (because of previous spontaneous birth at ≤34 weeks and 0 days of gestation, or a cervical length ≤25 mm, or because of a positive fetal fibronectin test combined with other clinical risk factors for preterm birth [any one of a history in a previous pregnancy of preterm birth, second trimester loss, preterm premature fetal membrane rupture, or a history of a cervical procedure to treat abnormal smears]). The objective of the study was to determine whether vaginal progesterone prophylaxis given to reduce the risk of preterm birth affects neonatal and childhood outcomes. We defined three primary outcomes: fetal death or birth before 34 weeks and 0 days gestation (obstetric), a composite of death, brain injury, or bronchopulmonary dysplasia (neonatal), and a standardised cognitive score at 2 years of age (childhood), imputing values for deaths. Randomisation was done through a web portal, with participants, investigators, and others involved in giving the intervention, assessing outcomes, or analysing data masked to treatment allocation until the end of the study. Analysis was by intention to treat. This trial is registered at ISRCTN.com, number ISRCTN14568373. Between Feb 2, 2009, and April 12, 2013, we randomly assigned 1228 women to the placebo group (n=610) and the progesterone group (n=618). In the placebo group, data from 597, 587, and 439 women or babies were available for analysis of obstetric, neonatal, and childhood outcomes, respectively; in the progesterone group the corresponding numbers were 600, 589, and 430. After correction for multiple outcomes, progesterone had no significant effect on the primary obstetric outcome (odds ratio adjusted for multiple comparisons [OR] 0·86, 95% CI 0·61–1·22) or neonatal outcome (OR 0·72, 0·44–1·17), nor on the childhood outcome (cognitive score, progesterone group vs placebo group, 97·3 [SD 17·9] vs 97·7 [17·5]; difference in means –0·48, 95% CI –2·77 to 1·81). Maternal or child serious adverse events were reported in 70 (11%) of 610 patients in the placebo group and 59 (10%) of 616 patients in the progesterone group (p=0·27). Vaginal progesterone was not associated with reduced risk of preterm birth or composite neonatal adverse outcomes, and had no long-term benefit or harm on outcomes in children at 2 years of age. Efficacy and Mechanism Evaluation (EME) Programme, a Medical Research Council (MRC) and National Institute for Health Research (NIHR) partnership. The EME Programme is funded by the MRC and NIHR, with contributions from the Chief Scientist Office in Scotland and National Institute for Social Care and Research in Wales.

Gestational trophoblastic disease encompasses a range of pregnancy-related disorders, consisting of the premalignant disorders of complete and partial hydatidiform mole, and the malignant disorders of invasive mole, choriocarcinoma, and the rare placental-site trophoblastic tumour. These malignant forms are termed gestational trophoblastic tumours or neoplasia. Improvements in management and follow-up protocols mean that overall cure rates can exceed 98% with fertility retention, whereas most women would have died from malignant disease 60 years ago. This success can be explained by the development of effective treatments, the use of human chorionic gonadotropin as a biomarker, and centralisation of care. We summarise strategies for management of gestational trophoblastic disease and address some of the controversies and future research directions.

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. The thymus is essential for T cell maturation and selection, and thymic defects result in severe immune problems. Here the authors identify a thymus cell population that is expandable in vitro, and can repopulate natural thymic matrix to generate tissue that supports mature T cell development in vitro and in vivo.

Hepatic tissue engineering using decellularized scaffolds is a potential therapeutic alternative to conventional transplantation. However, scaffolds are usually obtained using decellularization protocols that destroy the extracellular matrix (ECM) and hamper clinical translation. We aim to develop a decellularization technique that reliably maintains hepatic microarchitecture and ECM components. Isolated rat livers were decellularized by detergent-enzymatic technique with (EDTA-DET) or without EDTA (DET). Histology, DNA quantification and proteomics confirmed decellularization with further DNA reduction with the addition of EDTA. Quantification, histology, immunostaining, and proteomics demonstrated preservation of extracellular matrix components in both scaffolds with a higher amount of collagen and glycosaminoglycans in the EDTA-DET scaffold. Scanning electron microscopy and X-ray phase contrast imaging showed microarchitecture preservation, with EDTA-DET scaffolds more tightly packed. DET scaffold seeding with a hepatocellular cell line demonstrated complete repopulation in 14 days, with cells proliferating at that time. Decellularization using DET preserves microarchitecture and extracellular matrix components whilst allowing for cell growth for up to 14 days. Addition of EDTA creates a denser, more compact matrix. Transplantation of the scaffolds and scaling up of the methodology are the next steps for successful hepatic tissue engineering.

Perinatal and paediatric autopsy rates are at historically low levels with declining uptake due to dislike of the invasiveness of the procedure, and religious objections particularly amongst Muslim and Jewish parents. Less invasive methods of autopsy including imaging with and without tissue sampling have been shown to be feasible alternatives. We sought to investigate attitudes including religious permissibility and potential uptake amongst members of the Muslim and Jewish communities in the United Kingdom. Semi-structured interviews with religious and faith-based authorities (n = 16) and bereaved parents from the Jewish community (n = 3) as well as 10 focus groups with community members (60 Muslim participants and 16 Jewish participants) were conducted. Data were analysed using thematic analysis to identify key themes. Muslim and Jewish religious and faith-based authorities agreed that non-invasive autopsy with imaging was religiously permissible because it did not require incisions or interference with the body. A minimally invasive approach was less acceptable as it still required incisions to the body, although in those circumstances where it was required by law it was more acceptable than a full autopsy. During focus group discussions with community members, the majority of participants indicated they would potentially consent to a non-invasive autopsy if the body could be returned for burial within 24 hours, or if a family had experienced multiple fetal/pregnancy losses and the information gained might be useful in future pregnancies. Minimally invasive autopsy was less acceptable but around half of participants might consent if a non-invasive autopsy was not suitable, with the exception of the Jewish Haredi community who unanimously stated they would decline this alternative. Our research suggests less invasive autopsy offers a viable alternative to many Muslim and Jewish parents in the UK who currently decline a full autopsy. The findings may be of importance to other countries with significant Muslim and/or Jewish communities as well as to other religious communities where concerns around autopsy exist. Awareness-raising amongst religious leaders and community members will be important if these methods become routinely available.

Perinatal autopsy is the standard method for investigating fetal death; however, it requires dissection of the fetus. Human fetal microfocus computed tomography (micro-CT) provides a generally more acceptable and less invasive imaging alternative for bereaved parents to determine the cause of early pregnancy loss compared with conventional autopsy techniques. In this protocol, we describe the four main stages required to image fetuses using micro-CT. Preparation of the fetus includes staining with the contrast agent potassium triiodide and takes 3–19 d, depending on the size of the fetus and the time taken to obtain consent for the procedure. Setup for imaging requires appropriate positioning of the fetus and takes 1 h. The actual imaging takes, on average, 2 h 40 min and involves initial test scans followed by high-definition diagnostic scans. Postimaging, 3 d are required to postprocess the fetus, including removal of the stain, and also to undertake artifact recognition and data transfer. This procedure produces high-resolution isotropic datasets, allowing for radio-pathological interpretations to be made and long-term digital archiving for re-review and data sharing, where required. The protocol can be undertaken following appropriate training, which includes both the use of micro-CT techniques and handling of postmortem tissue. This protocol describes how to prepare and image human fetuses using microfocus computed tomography, a less invasive imaging alternative to conventional autopsy.