Heart disease 'reversed in mice'

Tiny fragments of genetic material can play a role in heart disease

Scientists have halted the advance of heart disease in mice - and even reversed some of its effects.

The study provides hard evidence that tiny pieces of genetic material called microRNA can play a key role in the development of heart disease.

The therapy, featured in the journal Nature, targets and blocks microRNA in heart cells.

A US specialist said that, with trials under way in other animals, human tests may be only a few years away.

This is one of the hottest topics in biology at the moment Professor Eric Olson University of Texas Southwestern Medical Center

The importance of microRNAs to heart disease - and a host of other diseases - has already been suggested by other scientists.

Their job is to regulate the activity of our genes, but with many different types present in the cell, scientists are trying to establish which plays the biggest role.

The US and German scientists are focusing on one type labelled microRNA-21, and their role in a type of heart cell called the cardiac fibroblast, which helps provide the structure of the organ, and plays a critical role in the progressive scarring which stops it working properly in heart disease.

Until recently, that process was thought to be an irreversible one.

The researchers found that cells in a failing heart had higher levels of this microRNA, and linked it to a chemical signalling pathway which leads to the tissue damage found in the condition.

Animal studies

In mice, they used a chemical which blocked microRNA-21, and found that not only that this pathway was interrupted, but that cardiac function in the animals improved.

This, they wrote, proved its potential as a new target for drugs in heart diseased humans.

Professor Eric Olson, from the University of Texas Southwestern Medical Center, whose own research focuses on microRNAs and heart disease, said that the results were "exciting".

"This is one of the hottest topics in biology at the moment," he said.

"Micro-RNAs are being very seriously considered as a therapeutic target - there is a lot of promise and potential in this area.

"This research suggests you can reverse or prevent aspects of heart disease."

He said: "There are already studies in large animals using micro-RNA inhibitors in heart disease - I can envisage that in a few years we will see this in human trials."

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