Original title: Growth phases of an active tissue: determinate, indeterminate, and proportionate
Jigyasa Watwani, K. Vijay Kumar, Vishal Vasan · August 2026
Living tissues can stop growing when they reach a certain size, or keep growing forever. Researchers wanted to explain how tissues choose between these paths. They built a physics model of tissue growing along one direction, where dividing and dying cells create internal pushing forces. Inside the tissue, these active pushing forces compete against the material's elasticity, which acts like a spring trying to hold things together. The team found two final outcomes. If the elastic strength can balance the active forces, growth stops at a fixed target size. But tissues have a limit on how much stress they can hold. If cell activity is too high, it overwhelms the elasticity, and the tissue keeps growing longer without stopping.
Imagine blowing up a balloon. Normally, the balloon stretches until the rubber's resistance balances the air pressure, and it stops growing. But if the rubber is too thin, the balloon keeps expanding without ever reaching a stable size. In this paper, the tissue is like the balloon: it grows until its internal forces are balanced by its stiffness. If the forces are too strong relative to the stiffness, the tissue never finds a balance and keeps elongating forever. The model also shows that if you have two balloons connected, their sizes settle into fixed proportions based on how stretchy each one is.
This matters because it explains why some tissues stop growing at a fixed size while others grow continuously, and how different parts of a tissue maintain their relative proportions. It shows that these growth patterns emerge from the same mechanical principles, without needing separate genetic instructions for each case.
The abstract doesn't explicitly state limitations, but the model is one-dimensional and continuum-based, so it may not capture discrete cell behaviors or three-dimensional growth patterns.
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Growth phases of an active tissue: determinate, indeterminate, and proportionate — Jigyasa Watwani, K. Vijay Kumar, Vishal Vasan
Abstract licence: CC0
Explanation generated by Synthesis from the abstract — it is not the original paper. This is a preprint, so it hasn't necessarily been peer reviewed.