A new therapeutic approach for treating high blood pressure is suggested in a study in mice published this week in Nature Communications. These results, if validated in humans, could be used to help control blood pressure in a significant number of people that do not respond to any available treatment.
Previous studies suggest that the nervous and immune systems are likely to be interacting in development of high blood pressure (hypertension), but this interplay has not been directly proven until now.
Giuseppe Lembo and his colleagues show that during early phases of high blood pressure development, mice exhibit increased nerve activity (sympathetic nerve discharge) to the spleen, a major organ of the immune system. This nerve discharge contributes to a subsequent immune response mediated by a subgroup of lymphocytes, termed T cells, that leave the spleen and enter the blood stream to infiltrate organs directly involved in blood pressure regulation, such as the kidneys and the aorta. The communication between the brain and the spleen is mediated by two nerves, the vagus and the splenic nerve, and it requires activity of a specific receptor on the splenic nerve, known as α7nAChRs.
In order to provide additional evidence that brain-spleen communication initiates hypertension development, the authors applied localized heat on the splenic nerve that permanently inhibited nerve activity. This surgical intervention prevented T cell egress from the spleen to the vasculature and kidneys, thereby preventing hypertension development in mice.