Lena Claesson-Welsh – Vascular biology
Blood vessels supply all tissues with blood, thereby delivering oxygen and nutrients and at the same time removing carbon dioxide and waste products. We study how blood vessels are formed and which factors control the process. A focus in the group is on leakage of fluid, molecules and cell from the blood into the tissues by passage between cell-cell junctions in the vessels. We ask how leakage affects tissue homeostasis and when dysregulated, can promote disease.
All growing tissues, both healthy and diseased, require formation of new blood vessels, angiogenesis. In diseases such as cancer angiogenesis is increased whereas other conditions can be accompanied by suppressed angiogenesis and poor circulation. Therefore, there is a therapeutic need to be able to both create new vessels and to prevent new vessels from forming.
In healthy adults no new blood vessels are formed, except during wound healing and in the female menstruation cycle. This means that usually angiogenesis is strictly controlled so that new vessels are formed only when needed. However, in several diseases, for instance cancer and eye diseases, exaggerated and chronic stimulation leads to formation of dysfunctional blood vessels. Blood vessels also allow for tumor cells to spread to other parts of the body, to metastasize. Substances that control angiogenesis might therefore function as cancer inhibiting drugs.
The growth factor VEGF regulates angiogenesis
A very important blood vessel stimulation factor is called VEGF (Vascular Endothelial Growth Factor). VEGF binds to specific receptors on the surface of the endothelial cells. This binding results in a signal that is transferred to the receptor and then on to intracellular signaling proteins, eventually leading to cell division. We are examining how this signal transduction occurs and which proteins are involved, with the aim to find angiogenic regulators.
Regulation of vessel permeability
Several projects in the group focus on how signal transduction regulates blood vessel permeability, i.e. how molecules and cells can pass from the blood to the surrounding tissues. Vessel permeability, which can be transient or permanent, can cause edema and tissue ischemia, thereby aggravating disease conditions and hamper therapies.
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