Dr. Karina Yaniv, who recently joined the Department of Biological Control at the Weizmann Institute, studies the interrelationships between blood vessels and lipids. This topic is part of a broader field being investigated in her laboratory: how blood vessels are formed in the fetus
It is important for all of us that the level of cholesterol and other fats in our blood be normal, but it seems that the blood vessels themselves do not really "care". Even when fat plugs threaten to block the blood flow, the blood vessels do not react to the danger and do not grow bypass tubes. The popular opinion is that the cells that make up the blood vessels do not "know" about the existence of the fat. But is it really so? If they were aware of the danger, how wonderful it would be if they themselves developed new tubes that would bypass the blockage, and prevent heart attacks.
Dr. Karina Yaniv, who recently joined the department of biological control at the institute, studies the interrelationship between blood vessels and lipids. This topic is part of a broader field that is studied in her laboratory: how blood vessels are formed in the fetus.
It has been known for a long time that the cells from which blood vessels are made, called endothelial cells, are sensitive to oxygen concentrations: as soon as the oxygen concentration in the blood drops, additional blood vessels are formed to ensure a sufficient supply of oxygen to the tissues. Unlike oxygen, scientists believed until recently that blood vessels were unable to "feel" fat. But in the post-doctoral research she carried out at the American National Institutes of Health, NIH, Dr. Yaniv provided the first experimental evidence for a new theory, according to which the endothelial cells actually feel the amount of fat in their environment and react accordingly. This research was done in zebrafish, which are a common model for studying molecular processes in animals Vertebrates, including humans Her research has shown that when the fat supply is low, zebrafish embryos grow vessels More blood, presumably to ensure high levels of essential nutrients, since fat molecules - such as those found in the egg yolk - make up the bulk of the food for the developing fetus. When the level of fat is high, the growth of blood vessels in the fetus stops.
At a later age, during adulthood, this biochemical dialogue between the fat and the blood vessel walls may act negatively: for example, when the cholesterol level in the blood is high, bypass tubes will not grow, even though such growth is exactly what is required to prevent blockage of blood vessels. In her new laboratory at the Weizmann Institute of Science, Dr. Yaniv is trying to identify the molecular signals transmitted between the lipids and the endothelial cells in the blood vessel walls.
Understanding the means of controlling the growth of blood vessels may have important consequences for human health, because such an understanding could allow doctors to increase or decrease the growth of new blood vessels as needed. Thus, for example, encouraging the growth of new blood vessels can be useful after a heart attack or stroke, or to prevent these diseases. Conversely, stopping the growth of blood vessels that feed a cancerous tumor may help treat cancer.
Development of blood vessels in the zebrafish embryo
A series of images taken with a confocal microscope following the development of blood vessels in a genetically modified zebrafish. You can see the growth and elongation of new capillaries from an existing blood vessel, which eventually form a new blood vessel on the dorsal (dorsal) side of the fish.
When Dr. Yaniv is not researching the development of blood vessels in the fetus, she focuses on the lymphatic system, which plays vital roles in the immune response, in the body's fluid metabolism and fat absorption. In her post-doctoral research, Dr. Yaniv showed that, contrary to popular opinion, zebrafish have lymphatic system. Thanks to this discovery, several laboratories in the USA and Europe began to use zebrafish in research on the lymphatic system. Dr. Yaniv also provided the first evidence in living organisms for an old hypothesis, about a century old, according to which the origin of the lymphatic vessels of the vertebrate fetus is in the veins.
Since the lymphatic system is involved in many disease-causing processes, this research may also help treat various diseases, especially cancer: the cancer cells spread to distant organs in the body through the lymphatic system. A good and detailed understanding of how the lymphatic vessels are formed in the fetus will perhaps allow them to be blocked around the cancerous tumor, and prevent the spread of metastases.
Dr. Yaniv chose to work with zebra fish, because they are an excellent model for her genetic research. Their small size allows her to keep an impressive number of 12,000 fish in a normal laboratory, in about 400 aquariums. The embryos of these fish are transparent, and it is easy to distinguish the blood and lymph vessels in them. Furthermore, it is convenient to carry out genetic manipulations in them. Thus, even though all the fish swimming vigorously in Yaniv's laboratory look the same, And striped with those "zebra stripes", some of them are actually transgenic: that is, their genome includes "reporter genes" which mark certain parts of the DNA using a phosphorescent dye. Other fish are mutants, and they lack the diversity and the large number of mutations produced in the laboratory will help to discover many genetic secrets essential to human health.
personal
Karina Yaniv was born in Córdoba, Argentina, and immigrated to Israel in 1989 as part of the Zionist youth movement. After a year at Kibbutz Magal, she began studying at the Hebrew University in Jerusalem, and in 2005 received a doctorate in developmental biology from the Hebrew University's School of Medicine and Hadassah. She then did post-doctoral research at the US National Institutes of Health, NIH, in Bethesda, Maryland, and in 2009 joined the faculty of the Weizmann Institute of Science as a senior researcher in the Department of Biological Control. Dr. Yaniv is married to Ram, a computer engineer, and the mother of three sons: 12-year-old Yotam, nine-year-old Nitai, and four-year-old Ilon. She says that in order to combine motherhood with scientific research, creative time management is required, for example, taking a break from work in the afternoon and returning to the laboratory late at night Hard work is a matter of routine for her. "When you do what you love, you strive to do it to the best of your ability," she says.
