Noninvasive Prenatal Testing Using Circulating DNA and RNA: Advances, Challenges, and Possibilities

Comprehensive evaluation of methods for identifying tissues or cell types of origin of the plasma cell-free transcriptome

Plasma cell-free RNA (cfRNA) is derived from cells in various tissues and organs throughout the body and reflects the physiological and pathological conditions. Identifying the origins of cfRNA is essential for comprehending its variations. Only a few tools are designed for cfRNA deconvolution, and most studies have relied on traditional bulk RNA methods. In this study, we employed human tissue and cell transcriptomic data as reference sets and evaluated the performance of seven deconvolution methods on cfRNA. We compared the analysis results of cell types and tissues of origin of plasma cfRNA and chose to use single-cell RNA sequencing (scRNA-seq) data as reference to conduct further evaluation of deconvolution methods. Subsequently, we assessed the accuracy and robustness of the methods by utilizing simulated cfRNA data generated from scRNA-seq. We also evaluated the methods' accuracy on real plasma cfRNA data by analyzing the correlation between the predicted cell proportions and the corresponding clinical indicators. Moreover, we compared the methods' effectiveness in revealing the impacts of diseases on cells and evaluated the performance of cancer classification models based on the cell origin data they provided. In summary, our study provides valuable insights into cfRNA origin analysis, enhancing its potential in biomedical research.

Non-coding RNAs: the architects of placental development and pregnancy success

Noncoding RNAs (ncRNAs) constitute a significant portion of the transcriptome that lacks evident protein-coding functions; however, they have been confirmed to be crucial in various biological processes, including placental development. Notwithstanding the existence of various ncRNAs, research on their role in placental development and pregnancy has been constrained. The predominant category of identified ncRNAs specific to placental tissue is microRNAs (miRNAs). Given their prevalence, the significantly larger cohort of other non-coding RNAs, such as circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs), is anticipated to exert a considerably greater influence than miRNAs. Syncytiotrophoblast, a fetal-derived cell, serves as a conduit between the fetus and mother by secreting extracellular vesicles that contain fetal proteins and RNA. Alterations in ncRNAs within placental tissue, especially in trophoblast cells and extracellular vesicles, may be linked to placental dysfunction that leads to pregnancy complications, serving either as a causative factor or a result. This review encapsulates the existing understanding of ncRNAs in placental development, pregnancy success, pregnancy-related complications, extracellular vesicle conveyance, and their capacity as innovative diagnostic instruments and therapeutic strategies.

[Burden of congenital birth defects in children under five in China from 1990 to 2021 and prediction of future trend]

OBJECTIVES

To study the incidence and disease burden of congenital birth defects in children under five in China from 1990 to 2021 and to predict the incidence of congenital birth defects in this population from 2022 to 2036, providing a reference for the prevention of congenital birth defects in children.

METHODS

Using the Global Burden of Disease Study 2021 (GBD 2021) database, the incidence and disability-adjusted life years (DALY) were employed to describe the disease burden. The Joinpoint regression model was used to analyze the trends in incidence and DALY rates of congenital birth defects in children under five. A grey prediction model GM(1,1) was applied to fit the trend of incidence rates of congenital birth defects in this age group and to predict the incidence from 2022 to 2036.

RESULTS

In 2021, the incidence rate of congenital birth defects among children under five in China was 737.28 per 100 000. Among these, congenital musculoskeletal and limb deformities had the highest incidence rate at 307.15 per 100 000, followed by congenital heart defects (223.53 per 100 000), congenital urinary and genital tract malformations (74.99 per 100 000), and congenital gastrointestinal malformations (62.61 per 100 000). From 1990 to 2021, the incidence rate and DALY rate of congenital birth defects in children under five in China decreased at an average annual rate of 1.73% and 5.42%, respectively. The prediction analysis indicated a decreasing trend in the incidence of congenital birth defects among children under five in China from 2022 to 2036, with the incidence rate dropping from 892.36 per 100 000 in 2022 to 783.35 per 100 000 in 2036.

CONCLUSIONS

The incidence and disease burden of congenital birth defects in children under five in China showed a significant declining trend from 1990 to 2021. It is predicted that this incidence will continue to decrease until 2036.

Novel biomarkers of fetal and neonatal environmental exposure, effect and susceptibility

Rapid advancements in science and technology have allowed medical providers to treat wider ranges of diseases with safer and more effective therapies than ever before. One of the areas of health that has been consistently understudied, however, is one that affects us all: environmental health or the effects that the chemicals we are exposed to every day have on our acute and chronic health. This effect can be exacerbated during and shortly after pregnancy, as an individual exposure is often shared by both the mother and the fetus/neonate. The diagnosis and monitoring of chemical exposure can be quite challenging, and improving our understanding of the effects of exposure will therefore require effective use of an expanding set of biomarker tests and biological matrices. This review covers the background and history of neonatal biomarkers of exposure, effect, and susceptibility, focusing on the potential uses for the non-invasive matrix of exhaled breath for the detection and monitoring of chemical exposures. IMPACT: Provides a brief overview of Food and Drug Administration and National Institutes of Health Joint Leadership Council BEST (Biomarkers, EndpointS, and other Tools) Resource. Summarizes new and potential biomarkers for fetal exposure. Collates studies using breath as a matrix for environmental exposures.

Liquid Biopsy Based on Cell-Free DNA and RNA

This review delves into the rapidly evolving landscape of liquid biopsy technologies based on cell-free DNA (cfDNA) and cell-free RNA (cfRNA) and their increasingly prominent role in precision medicine. With the advent of high-throughput DNA sequencing, the use of cfDNA and cfRNA has revolutionized noninvasive clinical testing. Here, we explore the physical characteristics of cfDNA and cfRNA, present an overview of the essential engineering tools used by the field, and highlight clinical applications, including noninvasive prenatal testing, cancer testing, organ transplantation surveillance, and infectious disease testing. Finally, we discuss emerging technologies and the broadening scope of liquid biopsies to new areas of diagnostic medicine.

Cell-Free Nucleic Acids for Early Prediction of Preeclampsia

PURPOSE OF REVIEW

This review summarizes the potential of cell-free nucleic acids for predicting preeclampsia, contrasts them with other methods, and discusses these findings' relevance to preeclampsia's pathogenesis and care.

RECENT FINDINGS

Recent studies have demonstrated the utility of cell-free nucleic acids in early preeclampsia risk prediction. Encouragingly, nucleic acid measurement exhibits similar or better sensitivity as compared to standard screening assays and furthermore sheds light on preeclampsia's underlying placental biology. Over the past decade, liquid biopsies measuring cell-free nucleic acids have found diverse applications, including in prenatal care. Recent advances have extended their utility to predict preeclampsia, a major cause of maternal mortality. These assays assess methylation patterns in cell-free DNA (cfDNA) or gene levels in cell-free RNA (cfRNA). Currently, preeclampsia care focuses on blood pressure control, seizure prevention, and delivery. If validated, early prediction of preeclampsia through liquid biopsies can improve maternal health and deepen our understanding of its causes.