Posted: February 27, 2010

Using nanoscale microscopy to evaluate individual regions on the surface of the heart

(Nanowerk News) Technological advances give the medical sector a huge boost, with people suffering from various disorders benefiting the most. A European team of researchers has developed a novel nanoscale scanning technique that gives experts a detailed look at how heart failure impacts the surface of a person's heart muscle cell. Presented in the Science journal, the findings may lead to better heart failure treatment and improved drugs that can slow the development of this serious condition.
Experts define heart failure as a condition in which a problem with the function or structure of the heart impairs its ability to supply enough blood flow to meet the body's needs. The problem gets even worse when the body activates hormones, such as adrenaline, to kick start the weak heart as the heart then suffers even more damage.
In this study, researchers from Imperial College London (ICL) in the UK, and the Institute of Pharmacology and Toxicology and the Rudolf Virchow Center, both at the University of W├╝rzburg in Germany, used nanoscale microscopy to evaluate individual regions on the surface of the heart muscle cell in healthy and failing rat hearts.
The technique, called scanning ion conductance microscopy (SICM), provides experts with a detailed image of the heart muscle cell's surface. Until now, experts have been using conventional live microscopy to determine how bad the damage is.
SICM gave the research team a glimpse into the fine structures of the cardiac muscle cell including minute tubes (i.e. transverse tubules) which carry electrical signals within a muscle cell. SICM also gave the researchers a detailed picture of the degree of disruption of the muscle's cell surface in heart failure.
The team said the body has two types of receptors for adrenaline: beta1-adrenoceptor (beta1-AR) and beta2-adrenoceptor (beta2-AR). Beta1-AR is responsible for stimulating the heart's contraction, but it can trigger cell damage in the long run. Beta2-AR can also get the heart to contract but it is equipped with unique protective properties.
SICM was combined with new chemical probes that give fluorescent signals when beta1-AR or beta2-AR is activated, according to the researchers. Their data show that beta2-AR receptors, which are usually anchored in the transverse tubules, change location and are found in the area where beta1-AR receptors are in the cells affected by heart failure. The team speculates that by moving into the same area as beta1-AR receptors, the beta2-AR receptors' protective properties are weakened, and in turn trigger faster degeneration of the failing heart.
'Our new technique means we can get a real insight into how individual cells are disrupted by heart failure,' explained co-author Dr Julia Gorelik from ICL's National Heart and Lung Institute. 'Using our new nanoscale live-cell microscopy we can scan the surface of heart muscle cells to much greater accuracy than has been possible before and [can] see tiny structures that affect how the cells function,' she added.
'Through understanding what's happening on this tiny scale, we can ultimately build up a really detailed picture of what's happening to the heart during heart failure and long term, this should help us to tackle the disease,' Dr Gorelik went on to say. 'The main question for our future research will be to understand whether drugs can prevent the beta2-AR from moving in the cell and how this might help us to fight heart failure.'
Source: Cordis