Whilst it is appropriate that we focus on prevention for potential heart attack candidates and the general public, the fact remains that around 6,000 people still suffer a myocardial infarction (MI) in Ireland each year. Heart disease is the most common cause of death here, and Irish women are seven times more likely to die from cardiovascular/heart disease than from breast cancer – a fact that needs to be brought home to the general public.
In the meantime, interventional cardiologists continue to deal with the fallout and one of the challenges of this is in the area of reducing cardiac tissue inflammation and promoting cell and tissue repair, especially in the immediate aftermath.
Just to recap on the basics: Following a heart attack, scar tissue forms, which of course interferes with muscle function and may lead to congestive heart failure. The rise and rise of the extracellular matrix (ECM) has been making waves for some time now in dermatology, as anybody who reads our regular reports from the UCD Charles Institute dermatology seminars will know. Researchers have also been injecting hydrogel ECMs directly into damaged heart muscle tissue via a catheter. However, due to potential complications with injecting directly into the muscle, it has previously only been appropriate for a week or more following the heart attack.
Now, folks at the University of California have announced a groundbreaking biomaterial that can be injected intravenously and reduces tissue inflammation, as well as promoting tissue and cell repair. Unlike its previous iteration, this procedure is designed to be administered immediately after a heart attack at the same time as other treatments, such as a stent or angioplasty.
The treatment is quite targeted – it can be evenly distributed throughout damaged tissue, because it’s infused or injected intravenously. On the other hand, ECM hydrogel injected through a catheter stays in specific locations and does not spread out. The genesis of the research involved using a hydrogel the researchers had developed that was proven to be compatible with blood injections as part of safety trials. However, the particle size in the hydrogel was too large to accurately target leaky blood vessels. The researchers solved this problem by running the liquid precursor of the hydrogel through a centrifuge, which allowed for sifting-out bigger particles and keeping only nano-sized ones. The resulting material was then put through dialysis and sterile filtering before being freeze-dried.
Add sterile water to the final powder, and presto – you have a biomaterial that can be injected intravenously or infused into a coronary artery in the heart. The biomaterial has already been tested and proven effective in treating tissue damage caused by MI in both rodent and large animal models. The team has also provided proof of concept in a rodent model that the biomaterial could be beneficial to patients with a number of other conditions. A study on the safety and efficacy of the biomaterial in human subjects could start as soon as one-to-two years from now.
“This biomaterial allows for treating damaged tissue from the inside out,” according to Prof Karen Christman, Professor of Bioengineering at the University of California San Diego, and the lead researcher. “It’s a new approach to regenerative engineering.”
According to Dr Martin Spang (PhD), the paper’s first author: “We sought to design a biomaterial therapy that could be delivered to difficult-to-access organs and tissues, and we came up with the method to take advantage of the bloodstream – the vessels that already supply blood to these organs and tissues…. While the majority of work in this study involved the heart, the possibilities of treating other difficult-to-access organs and tissues can open up the field of biomaterials/tissue engineering into treating new diseases.”
If you want to drill down into the details, the paper was published in Nature Biomedical Engineering. If followed through to successful realisation, and made widely available, the procedure has huge potential in a wide range of conditions beyond heart attack, including for traumatic brain injuries and pulmonary arterial hypertension. If all goes well, perhaps it will add an important weapon to the arsenal of interventional cardiologists and others.
Watch this space.