Connecting clinical, environmental, and genetic factors point to an essential role for vitamin A signaling in the pathogenesis of congenital diaphragmatic hernia

Cellular origins and translational approaches to congenital diaphragmatic hernia

Congenital Diaphragmatic Hernia (CDH) is a complex developmental abnormality characterized by abnormal lung development, a diaphragmatic defect and cardiac dysfunction. Despite significant advances in management of CDH, mortality and morbidity continue to be driven by pulmonary hypoplasia, pulmonary hypertension, and cardiac dysfunction. The etiology of CDH remains unknown, but CDH is presumed to be caused by a combination of genetic susceptibility and external/environmental factors. Current research employs multi-omics technologies to investigate the molecular profile and pathways inherent to CDH. The aim is to discover the underlying pathogenesis, new biomarkers and ultimately novel therapeutic targets. Stem cells and their cargo, non-coding RNAs and agents targeting inflammation and vascular remodeling have produced promising results in preclinical studies using animal models of CDH. Shortcomings in current therapies combined with an improved understanding of the pathogenesis in CDH have given rise to novel promising experimental treatments that are currently being evaluated in clinical trials. This review provides insight into current developments in translational research, ranging from the cellular origins of abnormal cardiopulmonary development in CDH and the identification of novel treatment targets in preclinical CDH models at the bench and their translation to clinical trials at the bedside.

The etiology of congenital diaphragmatic hernia: the retinoid hypothesis 20 years later

Congenital diaphragmatic hernia (CDH) is a severe birth defect and a major cause of neonatal respiratory distress. Impacting ~2-3 in 10,000 births, CDH is associated with a high mortality rate, and long-term morbidity in survivors. Despite the significant impact of CDH, its etiology remains incompletely understood. In 2003, Greer et al. proposed the Retinoid Hypothesis, stating that the underlying cause of abnormal diaphragm development in CDH was related to altered retinoid signaling. In this review, we provide a comprehensive update to the Retinoid Hypothesis, discussing work published in support of this hypothesis from the past 20 years. This includes reviewing teratogenic and genetic models of CDH, lessons from the human genetics of CDH and epidemiological studies, as well as current gaps in the literature and important areas for future research. The Retinoid Hypothesis is one of the leading hypotheses to explain the etiology of CDH, as we continue to better understand the role of retinoid signaling in diaphragm development, we hope that this information can be used to improve CDH outcomes. IMPACT: This review provides a comprehensive update on the Retinoid Hypothesis, which links abnormal retinoic acid signaling to the etiology of congenital diaphragmatic hernia. The Retinoid Hypothesis was formulated in 2003. Twenty years later, we extensively review the literature in support of this hypothesis from both animal models and humans.

Global, regional, and national burden of inguinal, femoral, and abdominal hernias: a systematic analysis of prevalence, incidence, deaths, and DALYs with projections to 2030

BACKGROUND

Hernias, particularly inguinal, femoral, and abdominal, present a global health challenge. While the Global Burden of Disease (GBD) study offers insights, systematic analyses of hernias remain limited. This research utilizes the GBD dataset to explore hernia implications, combining current statistics with 2030 projections and frontier analysis.

METHODS

We analyzed data from the 2019 GBD Study, focusing on hernia-related metrics: prevalence, incidence, deaths, and disability-adjusted life years (DALYs) across 204 countries, grouped into 21 GBD regions by the SDI (SDI). Data analysis incorporated relative change calculations, Annual Percentage Change (APC), Average Annual Percentage Change (AAPC), and Joinpoint Regression Analysis. The study also employed frontier analysis and the Bayesian Age-Period-Cohort model for trend prediction up to 2030. Analyses utilized R version 4.2.3.

RESULTS

From 1990 to 2019, global hernia cases surged by 36%, reaching over 32.5 million, even as age-standardized rates declined. A similar pattern was seen in mortality and DALYs, with absolute figures rising but age-standardized rates decreasing. Gender data between 1990 and 2020 showed consistent male dominance in hernia prevalence, even as rates for both genders fell. Regionally, Andean Latin America had the highest prevalence, with Qatar and Bulgaria noting significant increases and decreases, respectively. Frontier analyses across 204 countries linked higher SDIs with reduced hernia prevalence. Yet, some high SDI countries, like Qatar and the UK, deviated unexpectedly. Predictions up to 2030 anticipate increasing hernia prevalence, predominantly in males, while death rates are expected to decline. DALYs, after declining, are stabilizing.

CONCLUSIONS

Our analysis reveals a complex interplay between socio-demographic factors and hernia trends, emphasizing the need for targeted healthcare interventions. Despite advancements, vigilance and continuous research are essential for optimal hernia management globally.

Molecular insights using spatial transcriptomics of the distal lung in congenital diaphragmatic hernia

Abnormal pulmonary vascular development and function in congenital diaphragmatic hernia (CDH) is a significant factor leading to pulmonary hypertension. The lung is a very heterogenous organ and has marked cellular diversity that is differentially responsive to injury and therapeutic agents. Spatial transcriptomics provides the unmatched capability of discerning the differences in the transcriptional signature of these distinct cell subpopulations in the lung with regional specificity. We hypothesized that the distal lung parenchyma (selected as a region of interest) would show a distinct transcriptomic profile in the CDH lung compared with control (normal lung). We subjected lung sections obtained from male and female CDH and control neonates to spatial transcriptomics using the Nanostring GeoMx platform. Spatial transcriptomic analysis of the human CDH and control lung revealed key differences in the gene expression signature. Increased expression of alveolar epithelial-related genes (SFTPA1 and SFTPC) and angiogenesis-related genes (EPAS1 and FHL1) was seen in control lungs compared with CDH lungs. Response to vitamin A was enriched in the control lungs as opposed to abnormality of the coagulation cascade and TNF-alpha signaling via NF-kappa B in the CDH lung parenchyma. In male patients with CDH, higher expression of COL1A1 (ECM remodeling) and CD163 was seen. Increased type 2 alveolar epithelial cells (AT-2) and arterial and lung capillary endothelial cells were seen in control lung samples compared with CDH lung samples. To the best of our knowledge, this is the first use of spatial transcriptomics in patients with CDH that identifies the contribution of different lung cellular subpopulations in CDH pathophysiology and highlights sex-specific differences.NEW & NOTEWORTHY This is the first use of spatial transcriptomics in patients with congenital diaphragmatic hernia (CDH) that identifies the contribution of different lung cellular subpopulations in CDH pathophysiology and highlights sex-specific differences.