A single drop of blood brings cells to attention
Several studies have already attempted to visualize the cellular ballet that starts after an injury and at the start of the healing process. This study from the Universities of Oslo and Eindhoven shows how a single drop of blood induces skin cells to align, and how this first connection between cells precedes a much more pronounced collective and coordinated cell migration, spanning distances micrometric or even millimetric. Data that gives rise here, in the journal Nature Communications, to the development of a simulation model that opens up new perspectives on the mechanisms of healing.
What happens to skin cells when they encounter blood?
The team from Oslo University Hospital carried out experiments on blood-deprived cells, which were subsequently exposed to blood serum. Remarkably, the experiment shows that all cells begin to move and migrate in the same direction, that of the blood serum.
Each of us will sustain approximately 10,000 injuries in our lifetime, ranging from minor cuts to traumatic wounds or surgical wounds. In most cases, the wounds heal, but in some cases the healing process is faulty and leads to the development of a chronic wound. In particular during aging and in the event of certain pathologies including diabetes and obesity.
Blood plays an important and independent role in wound healing :
Different molecular components of blood trigger tissue repair processes after injury. Here, researchers are looking at what happens when dormant skin cells come into contact with blood when no wound is present. Blood serum alone induces spontaneous movement (migration) and growth (proliferation) of cells, 2 essential processes or phases in wound healing. Cell divisions are polarized and align with the direction of cell migration, a valuable new insight or knowledge for tissue repair. In short, the presence of blood serum is sufficient to activate dormant skin cells into a migratory and proliferative state and the wound edge,
A “connectivity” also takes place between the cells and whereas the cells which remain disconnected or isolated only follow random individual movements, strong connectivities between cells take place, resulting in a much more pronounced collective and coordinated cell migration. , covering distances of several millimeters.
A digital simulation model is thus developed by these scientists, which imitates the shape and movement of cells in the presence and absence of blood. In this model, cells deprived of blood remain quiescent, while the addition of blood activates the cells and sets them in motion. Simulations indicate that enhanced cell-cell connectivity causes cells to align more tightly with their neighbors, giving rise to the large-scale collective motion observed in previous experiments.
Inflammation and increased blood flow to the wound site can be activated without having an open wound , for example by bruising. The scientists believe that their results may be relevant in this area: “ It can be assumed, based on these new data, that cell migration is also activated in these situations.
In fact, our skin cells are said to be much more active and dynamic than previously thought and that this skin dynamic here regulated by blood can also occur in many other situations ”.
The next step will be to understand why the presence of blood triggers this cell activity and why cells divide asymmetrically in the direction of cell migration!