Water constitutes about 60 percent of the human body, with a significant portion of it existing inside cells and the rest flowing between cells. Researchers from MIT have discovered that this intercellular fluid plays a crucial role in how tissues respond to physical deformation. Their findings have implications for understanding how cells, tissues, and organs adapt to various conditions like aging, cancer, and neuromuscular diseases.

Published in Nature Physics, the study reveals that tissues are more compliant and relax faster when the fluid between cells flows easily during compression. Conversely, tissues become stiffer and resist deformation when there is less room for intercellular flow. This challenges the conventional belief that a tissue's compliance depends on its internal rather than external environment.

The results of this research can be applied to comprehend how muscles recover from injury, the impact of physical adaptability on aging and cancer progression, and the design of artificial tissues and organs. Intercellular flow optimization within tissues could enhance their function and resilience, potentially aiding in nutrient or therapy delivery for tissue healing or tumor eradication.

Lead author Fan Liu and co-author Ming Guo, an associate professor of mechanical engineering at MIT, along with other researchers, conducted experiments on tissue deformation and intercellular flow. They observed that intercellular flow influences how tissues respond to deformation, shedding light on the mechanics of tissue behavior.

Fluid Dynamics in Tissues

The researchers studied intercellular flow in various biological tissues, including pancreatic tissue cells. By culturing tissue clusters and subjecting them to compression using a custom-built testing platform, they found that the larger the tissue cluster, the longer it took to relax, indicating the dominance of intercellular flow in tissue response to deformation.

Future research will explore the impact of intercellular flow on brain function, particularly in conditions like Alzheimer's disease. Enhancing intercellular flow could aid in waste removal and nutrient delivery to the brain, suggesting potential therapeutic applications.

Overall, this study underscores the significance of intercellular flow in tissue mechanics and its implications for tissue engineering and disease research. By understanding how fluid dynamics influence tissue behavior, researchers can develop new strategies for improving tissue function and health outcomes.