Prize for ground-breaking knowledge on how blood vessels are formed

Published 2010-10-29 00:00. Updated 2013-11-26 10:24

[PRESS RELEASE 2010-10-26] The Axel Hirsch Doctor of Medicine Prize for 2010 has been awarded to Professor Christer Betsholtz of the Department of Medical Biochemistry and Biophysics at Karolinska Institutet. He receives the prize for a series of internationally noted and widely cited research papers on how blood vessels are formed (angiogenesis).

The Board of Research at Karolinska Institutet has decided that the Axel Hirsch Doctor of Medicine Prize for 2010 will go to Professor Christer Betsholtz.

He has shown the significance of different cell types for vascular growth. Particularly ground-breaking is his identification of the "tip cells" that control the direction of growth. Professor Betsholtz´s work is not just of basic scientific interest but can also increase understanding of, and lead to new methods of treatment for, diseases in humans such as tumours, says Martin Ingvar, Dean of Research.

Several research teams across the world have focused their research on understanding how blood vessels are formed, both normally and in disease, and the cellular mechanisms that contribute to the uninhibited growth of vessels. Professor Betsholtz and his team are primarily studying how blood vessels are formed normally during the fetal stage. The research is partly concerned with mapping which genes are active during this process.

We use various models to understand what function the genes have. We can either delete a particular gene and see what the effect is or, conversely, overexpress it. By also using modern techniques such as DNA micromatrices it is possible to study on a larger scale which genes are involved in the development of blood vessels, says Professor Betsholtz.

The mapping applies to all the genes that are specifically expressed in both the cell types of the blood vessels, that is to say endothelial cells and pericytes. Pericytes are the smooth muscle cells of the smallest blood vessels. Professor Betsholtz has also shown that pericytes may play different roles depending on the type of tissue in which they occur. He has studied how pericytes are formed in blood vessels in tumours.

This too varies according to type of tumour. Some tumours are worse at recruiting pericytes and forming new blood vessels. We believe that this may be of significance to how medicines can be taken up by the tumour and how the cells of the immune system are permitted to pass from the bloodstream into the tumour tissue.

The blood vessels of the brain contain a particularly large number of pericytes, and in recent years Professor Betsholtz´s team has started to understand the role the pericytes also play here.

They regulate what is known as the blood-brain barrier, which protects the brain from harmful substances in the blood and forms a powerful obstacle to the passage of medicines into the brain. Increased understanding of the blood-brain barrier may be of great significance to our prospects of treating diseases in the brain, such as stroke and Alzheimer's disease," says Professor Betsholtz.

Although research on angiogenesis has taken a massive step forward in recent years, there are still many unknown factors controlling this process. We need to learn far more about which molecular and cellular mechanisms determine how blood vessels are formed and what decides their role. Only then can we seriously start to think about developing tailored medicines that inhibit or stimulate the growth of blood vessels and modify the functions of the blood vessels, he says.

Christer Betsholtz was born in Stockholm in 1959. He defended his thesis on the role of the growth factor PDGF in tumour development in Uppsala in 1986. The following year be became a docent. He held several research posts over the period 1986-1993 with support from the Swedish Cancer Society and the Swedish Research Council among others. In 1994 he became Professor of Medical and Physiological Chemistry at the University of Gothenburg. He has been a scientific member of research councils both in Sweden and abroad, such as the Swedish Cancer Society, the Swedish Research Council and the Swedish Foundation for Strategic Research. He is a member of European Molecular Biology Organisation (EMBO), Academia Europea and the Royal Swedish Academy of Sciences. He was appointed Professor of Vascular Biology at Karolinska Institutet on 1 July 2004.

Hirsch Prize

The Axel Hirsch Doctor of Medicine Prize is awarded annually by the Karolinska Institutet Board of Research as "reward for a scientific paper of high value published by a Swedish researcher. Prize-winners are chosen through a nomination process.

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