Immune System Has Great Say in Blood Pressure
High blood pressure has been associated with fatal cardiovascular diseases, especially in developed countries.
Although a high level of salt in the body has been considered a risk factor for quite some time, it is not associated with all kinds of high blood pressure, which has mystified scientists for a long time.
However, a new study by Professor Jens Titze of Vanderbilt University, Nashville, Tennessee and the University of Erlangen points out that the skin and the immune system play a significant role in the regulation of the sodium balance and hypertension in the body.
The water and salt balance regulate the blood pressure in the body, and one of the key roles is played by the kidney. Kidney regulates the water retention and excretion from the body, which in turn determines the volume of blood, influencing blood pressure.
However, according to the revelations of the study by Professor Titze, show that organs and systems of the body, the skin and the immune system, which were never before associated with the levels of water and salt in the body, do influence blood pressure.
"The sodium concentration can be higher in the skin than in blood. This means that not only the kidney regulates sodium balance but that there must be additional mechanisms," Professor Titze explained.
His research team further demonstrated how the immune system is significant for this mechanism: A specific type of immune cells, the macrophages - literally "big eaters" in Greek - recognize high sodium levels in the skin, Medical Xpress reported.
They subsequently activate a gene that in turn ensures that the vascular endothelial growth factor (VEGF-C) is released in large amounts into the skin. VEGF-C controls the growth of lymphatic vessels that transport fluid and sodium. If this factor is released in higher amounts, lymphatic vessels grow into the skin and ensure that the stored sodium can be transported away again, the report said.
While experimenting on mice, the researchers blocked this mechanism, which resulted in them developing high blood pressure.
"The immune cells apparently regulate salt balance and blood pressure," Titze said. "In addition, data from a first clinical study showed that large amounts of salt are stored in the skin of patients with high blood pressure."