Scientists have created a “map” of the developing human heart

The heart, the first organ to develop in mammals, is composed of highly organized structures that must be coordinated to function properly. The research team was able to create a spatial map of the developing human heart at single-cell resolution.

Details of the study are published this Wednesday in the journal Nature in a paper by scientists from the University of California, San Diego, US, which shows how cells organize themselves as the heart develops.

Despite the organ’s importance, scientists know little about exactly how its cells are organized, not knowing, for example, how they are spatially coordinated to create the complex morphological structures critical to cardiac function.

This comprehensive cellular “atlas” expands on exactly that knowledge and shows how different types of heart cells interact and organize into the complex structures needed for heart function, news agency Efe reported on Wednesday.

If these muscle structures in this organ do not form correctly, congenital heart disease, the most common birth defect, can occur, and some heart diseases can also develop in adulthood, the authors remind.

To map the heart, researchers led by Eli Farah, Quan Zhu and Neil Chi combined RNA sequencing and advanced imaging technologies, according to the journal.

With these single-cell technologies, they were able to create an improved list of human heart cell types.

The map revealed the regional distribution of a wide range of cardiac cell subpopulations, revealing how these cells interact during heart development.

Single-cell analysis identified 75 subpopulations that exhibited characteristics consistent with their anatomical location and developmental stage, including novel cell subtypes in heart valves.

In addition, the authors discovered interactions between specific combinations of cell populations. They observed, for example, interactions between ventricular cardiac muscle cells, fibroblasts (part of the connective tissue) and endothelial cells (the lining of blood vessels), which may play a role in the formation of the ventricular wall.

Specifically, the research team used a spatial imaging technique called Merfish, which allowed for preliminary spatial identification of individual cells.

Together with single-cell transcriptomics, which reveals which genes are expressed in which cells (the transcriptome), the scientists have achieved “unprecedented” resolution and depth of understanding of individual cells and where they are located.

The detailed information revealed in this study may help improve understanding of the mechanisms underlying congenital and adult heart defects and may also provide the basis for new strategies for cardiac repair, the authors conclude.