According to a study published in the academic journal Hypertension, researchers from the University of Leicester's Department of Cardiovascular Sciences have made a pioneering discovery into the causes of high blood pressure (hypertension) during their analysis of genetic material in human kidneys in search of genes that might contribute to hypertension that could pave the way for future studies.

Researchers discovered key genes in the kidneys, the messenger RNAs and micro RNAs, which may contribute to human hypertension. Furthermore, they also uncovered two microRNAs, a hormone long thought to be involved in controlling blood pressure, which contribute to the regulation of renin.

Despite scientists being long aware that kidneys are involved in regulating blood pressure, it is the first time that researchers have identified key genes that play a role in the process and also identified miRNAs that control the expression of the hormone rennin.

The findings were made during a large, comprehensive gene expression analysis of human kidneys, using various techniques to study the genes mRNAs and miRNAs that are present in the medulla, the inner part of the kidney and the cortex, the kidney's outer part. The researchers examined kidney tissue samples from 15 male hypertensive patients and 7 male patients with normal blood pressure and compared both groups' messenger RNA (mRNA) and micro RNA (miRNA).

Messenger RNA (mRNA) is a single-stranded molecule that assists in the production of protein from DNA, whereby genetic information is copied from DNA to mRNA strands, providing a template that enables the cell to produce new proteins. The process of converting mRNA into proteins is regulated in part by a very small molecule called MicroRNA (miRNA).

The human kidneys samples were obtained from the Silesian Renal Tissue Bank (SRTB) that stores human kidney samples for use in genetic research into cardiovascular diseases. All samples were from Polish male individuals of white European ancestry. Researchers selected samples from 15 patients with hypertension, together with samples of 7 patients with normal blood pressure who they used as the control group.

Co-author Dr Maciej Tomaszewski, at the University of Leicester and Senior Clinical Lecturer in Cardiovascular Medicine in the Department of Cardiovascular Sciences, as well as Consultant Physician in Leicester Blood Pressure Clinic, a European Centre of Excellence, commented:

"I am very excited about this publication. Renin is one of the most important contributors to blood pressure regulation. The novel insights into its expression within the human kidney from this study open up new avenues for the development of new antihypertensive medications. The collection of hypertensive and normotensive kidneys is available for our studies in Leicester thanks to a long-term international collaboration. We will continue using this unique research resource in our further studies to decipher the genetic background of human hypertension."

Researchers commented on the discovery of these miRNAs as "the first real evidence to implicate renin" as a cause of hypertension. Study findings also revealed which genes and miRNAs play a role in renin production. The obtained knowledge of the mechanisms for hypertension could pave the way for new novel hypertension therapies.

Written by Petra Rattue