Biological complexity: liver study of liquid crystal form (Introduction)

by David Turell , Wednesday, July 03, 2019, 15:30 (1758 days ago) @ David Turell

An attempt to understand how hepatocytes work:

https://medicalxpress.com/news/2019-07-technique-liquid-crystal-liver-tissue.html

"The liver is the largest metabolic organ of the human body with a complex tissue architecture. It is vital for blood detoxification and metabolism. Blood flows through blood vessels to the liver cells, called hepatocytes, which take up and metabolize substances and secrete bile for discharge into the intestine. How do cells interact with each other and self-organize to form a functional tissue? For this, its three-dimensional structure must be known. The architecture of tissues and its relation to their function are still poorly understood today.

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"A structural model of the liver lobule was made and hand-drawn by the anatomist Hans Elias in 1949. Since then, very little progress has been made. To solve this outstanding problem, the Dresden researchers computationally reconstructed the three-dimensional geometry of the tissue from microscopy images of mouse liver tissue and analyzed it applying concepts from Physics. Surprisingly, given the amorphous appearance of liver tissue, the researchers found that the hepatocytes follow a liquid-crystal order, similar to the one making electronic displays. Liquid crystals are less structured than crystals but are more organized than molecules in a liquid.

"Hernán Morales-Navarrete, postdoctoral researcher in the lab of Marino Zerial at the Max Planck Institute of Molecular Cell Biology and Genetics, explains: "Our results suggest that liver cells and sinusoids, which are the smallest blood vessels in the body, communicate with each other in both directions: The blood vessels instruct the hepatocytes and the hepatocytes send signals back to the blood vessels to establish and preserve the liquid-crystal order. This bi-directional communication is a central part of the self-organization of liver tissue." Such an architecture gives the tissue function and robustness against local damage.

Comment: This degree of complexity is not fully understood but the description is at least a beginning in understanding liver function. We know the functions, not the how. This must have been designed.