Why do lymphatic vessels form a jigsaw puzzle-like pattern?

Shape-shifting cells

In a study published in the journal Nature, a research group led by Professor Taija Mäkinen, Director at the Wihuri Research Institute, investigated how the thin layer of endothelial cells maintains its integrity under varying fluid pressure conditions. The study found that the key factor is the ability of the cells to continuously change their unique shape.

“It’s long been known that the endothelial cells of lymphatic vessels resemble oak leaves or jigsaw puzzle pieces. The reason for this peculiar shape has, however, remained a mystery, and researchers have previously been unable to replicate it in cultured cells,” says Mäkinen.

A similar jigsaw puzzle-like shape can be seen in a completely different type of cell: on the surface of plant leaves. In plants, this pattern helps cells withstand internal fluid pressure, which is vital for plant growth and structural support.

The fact that jigsaw puzzle-like cells function similarly in both plants and mammals points to a fundamental biological principle: for organisms of various types, this distinctive cell shape enhances structural stability. The same principle has been applied in human-led design as well: for example, paving stones on roads are frequently arranged in undulating or interlocking patterns to improve durability and wear resistance.