A video clip from Understanding Animal Research, a UK organisation which tries to tackle some of the misunderstandings about animal research. This kind of open advocacy which allows people to see the conditions of animals in labs is an important step in winning and keeping public support for lifesaving medical research.
Notice the use of clicker training to get the animals to do simple tasks such as jump on the weighing scales – this reduces any stress that might be caused by trying to force the beagle to do this unwillingly. This is just one of the many enrichment techniques used to improve animal welfare in laboratories around the world.
An excellent example of the value of dogs in biomedical research is provided by a BBC report “‘Heart shrinking’ trial to combat heart failure to begin” on the launch of a multi-centre trial (see clinicaltrials.gov for details) to evaluate whether electrical stimulation of the vagus nerve can reduce cardiac hypertrophy and arrhythmia, and improve heart function in patients with heart failure. The BBC report acknowledges that “The technique is being trialled in humans after it was shown to keep rats and dogs alive for longer” and links to a 2003 paper which found that electrical stimulation of the vagus nerve increases survival in a rat model of cardiac hypertrophy.
This technique is based on a discovery made in 1984 (1), when scientists showed that an imbalance in the autonomic nervous system – part of the nervous system that acts as a control system functioning and is comprised of parasympathetic nervous system (PSNS) and sympathetic nervous system (SNS) – has a critical role in the induction of lethal ventricular arrhythmias in dogs following heart attack, with an increase in SNS activity leading to abnormal heart rate, heart tissue growth, and heart failure. Over the past decades several drugs have been developed to treat heart failure by reducing heart tissue growth – the ‘heart shrinking’ referred to in the BBC report – and heart rate, for example Ivabradine whose development we discussed recently, but more recently another approach has received attention, modulating the PSNS through stimulation of the vagus nerve in order to rebalance the autonomic nervous system inputs into the heart.
Following a series of studies which demonstrated that stimulation of the vagus nerve could prevent death and improve heart function in a variety rat and dog models of cardiac dysfunction and heart failure (including the study mentioned by the BBC above), scientists demonstrated in that the beneficial effect of vagus nerve stimulation was additive when combined with drugs to treat heart failure in dogs. An open access review of these studies published in 2010 (2) by Professor Peter J Schwartz of the University of Pavia notes that:
An impressive aspect of these experimental studies is that they provide an unusually uniform picture of significant positive effects produced by chronic vagal stimulation in the failing heart. Furthermore, they also provide evidence for the important concept that the mechanism(s) underlying the protective effect of vagal stimulation involve something at least in part independent of the heart rate slowing.”
This result supported a decision to launch the first small phase I clinical trial of this technique in patients with heart failure, led by Professor Schwartz (3), which demonstrated the safety of the technique, and provided early hints of its effectiveness in 8 human patients. The much larger study whose launch was by the BBC uses a device manufactured by Boston Scientific rather than the BioControl Medical device used in the earlier study led by Prof. Schwartz, but is development was equally dependent on the same careful research in dog models of cardiac disease and heart failure.
It’s just one of many examples of why lab such as the one in the Understanding Animal Research video are so valued by the medical research community.
1) Schwartz PJ, Billman GE, Stone HL. “Autonomic mechanisms in ventricular fibrillation induced by myocardial ischemia during exercise in dogs with healed myocardial infarction. An experimental preparation for sudden cardiac death.” Circulation. 1984 Apr;69(4):790-800.PubMed: 6697463
2) Schwartz PJ.”Vagal stimulation for heart diseases: from animals to men. – An example of translational cardiology.-.” Circ J. 2011;75(1):20-7. PubMed: 21127379.
3) Schwartz PJ, De Ferrari GM, Sanzo A, Landolina M, Rordorf R, Raineri C, Campana C, Revera M, Ajmone-Marsan N, Tavazzi L, Odero A. “Long term vagal stimulation in patients with advanced heart failure: first experience in man.” Eur J Heart Fail. 2008 Sep;10(9):884-91. PubMed 18760668
Schwartz, P. (2011). Vagal Stimulation for Heart Diseases: From Animals to Men Circulation Journal, 75 (1), 20-27 DOI: 10.1253/circj.CJ-10-1019