April 17, 2024

Scientists Have Just Mapped Our Body Organs In Detail: ScienceAlert

A consortium of scientists has just published an atlas of remarkable images of three human organs, each vital in their own way, showing how cell types are organized and interact.

The result: Shimmering, kaleidoscopic blueprints lit by fluorescent dyes that reveal new relationships about our bodies and reshape our understanding of human biology and disease like never before.

As you can see in the diagram below, researchers generated the cell atlases in three ways.

Single-cell atlases of (a) the spleen, (b) the intestine, and (c) the kidney were generated in three ways. (Vento-Tormo & Vilarrasa-Blasi, nature2023)

One team, led by Washington University nephrologist Sanjay Jain, used single-cell transcriptional methods, which show how the genetic instructions encoded in DNA are read in individual cells, to map the kidney.

Another group led by genomicist Michael Snyder at Stanford School of Medicine mapped the intestine with fluorescent antibodies attached to sections of tissue, imaged under the microscope.

And the third team peered into what scientists have described as “arguably the most important organ of the body, but paradoxically the worst” – the placenta.

Stanford University pathologist Michael Angelo and colleagues imaging slices of placental tissue treated with metal ions chemically linked to antibodies capable of latching onto signature compounds on cell surfaces, targeting samples where placental cells were attached to the wall of the uterus.

A sequence of images showing placental cells during the early stages of pregnancy.
The mother’s cells in the uterine wall remodel themselves during early pregnancy to accommodate the placenta. (Greenbaum et al., nature2023)

By imaging multiple samples at different stages of this process, from 6 to 20 weeks gestation, the researchers outlined interactions between placental cells and immune cells and the mother’s arteries – both of which have adapted to accommodate the intestine.

We can see, in exquisite detail, how this remodeling process allows “a peaceful coexistence between genetically distinct maternal uterine cells and fetal placental cells,” according to two cell biologists at the Wellcome Sanger Institute, Roser Vento-Tormo and Roser Vilarrasa-Blasi, who wrote a commentary on a new collection of papers.

Two fluorescence microscopy images of placental cells at 6 and 16 weeks.
Placental cells during early pregnancy: at 6 (left) and 16 weeks (right). (Greenbaum et al., nature2023)

As for the intestine, it is this meter-long organ that millions of microbes scurry under, ultra-processed foods stimulate inflammationand cells are plugged into the body’s ‘second brain’.

Team Snyder he found out major changes in how cells are arranged along the length of the intestine. They sketched out distinct neighborhoods stacked with immune cells ready to be launched into action and walked on new subtypes of epithelial cells lining the gut.

More imaging of the ruffled surface of the intestine and a layers may reveal new insights into how inflammatory bowel diseases, mood disordersor even develop neurodegenerative diseases.

Fluorescence microscopy image of the intestinal wall and insert a typical histology section, for comparison.
New imaging techniques have helped compile a cell atlas of the intestine. Insert shows a typical histological section for comparison. (Michael Snyder/Hickey et al., nature2023)

Kidneys, too, do so much for the body. They pump blood to clear toxins and waste products, but often failure or become diseased and need to be replaced.

Sampling more than 90 kidneys, Jain and colleagues outlined cell-to-cell communication channels located where repair pathways become defective during acute kidney injury or chronic kidney disease.

“We looked at how kidney cells are organized, their molecular identity, and how they transition from healthy states to diseased states,” explains Jain, who led the kidney imaging study.

“With this information, we can begin to think about drugs or small molecule targets that may prevent progression to disease or promote recovery from injury.”

Remember that these images were taken using a small number of valuable samples from people undergoing surgery and volunteering to take part in research.

A much more difficult task will be to understand the structural differences in organs that exist between different groups and populations that may have real health consequences, even when we all have the same body plan.

The papers and their accompanying commentary have been published together in nature.

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