Nanoparticles tackle heart disease
When a person has a heart attack, it’s usually because a blockage has formed in one of the coronary arteries that supply blood to the heart muscle itself. This cuts off the supply of oxygen and nutrients to the tissue, which begins to die. One consequence of this is that the immune system moves in triggering inflammation, which can add further insult to the injury and exacerbate the damage. But drugs that can damp down inflammation can’t currently access the injured tissue very well. So a canny scientist from Taiwan has designed nanoparticles loaded with an anti-inflammatory drug cargo that can piggy back on the very same immune cells that migrate from the bloodstream into the damaged heart. Chris Smith spoke to Patrick Hsieh.
Patrick - What we’ve been trying to do is improve cardiovascular repair and regeneration after injury, particularly for a heart attack. Because after the cardiovascular event they will have ischemia which will cause tissue damage, and eventually they also have inflammation that will cause more and more damage to the tissues.
Chris - So when someone has say a heart attack and there’s a lack of blood flow to the heart muscle, that directly causes damage. But you also get inflammation and the inflammation causes damage and you’re saying you want to find a way to stop the inflammation?
Patrick - Right. Because the ischemia or lack of blood flow is short term damage. Information can prolong for weeks or even months and that causes progressive damage to the tissue.
Chris - So how are you trying to do this? How can you control the inflammation?
Patrick - We are tried to develop an anti-inflammatory drugs into the tissue but, as you can imagine, it is very difficult to directly deliver drugs into the injured sites, so we need some new technologies to help us.
Chris - But we’ve got lots of anti-inflammatory drugs - things like aspirin which we’ve had for a 100 plus years, so why is it a problem getting the drugs into the tissue?
Patrick - Because, as you can imagine, whenever you take a drug or you receive an injection of drugs they will be circulating into the whole body with very few going to the heart. So we need to develop a new technology to help them get to a specific area; one to deliver the drug for the heart.
Chris - And how are you doing that?
Patrick - We use nanotechnologies. We formulate nanoparticles and we load the anti-inflammatory drugs in the nanoparticles. And then we can add new targeting materials outside of the particles so once we inject it, the new nanodrugs, they will be specifically targeted to the heart.
Chris - Right. So you build a new nanoparticle that's got the drugs inside, but your problem is still how you get the nanoparticle to do where it’s needed. So you’ve got some crafty way of making the nanoparticle do that, so did you get the nanoparticle into say the injured heart then?
Patrick - We learned from mother nature. There are cells in the circulation called “monocytes.” They naturally we will go to the site of damage of the heart and we developed the nanomedicines which can stick to the monocytes so they will be brought into the damaged areas for delivering of the therapeutic drugs.
Chris - That’s crafty! So because there are these cells naturally going to damaged areas you’re piggybacking those cells with your nanoparticles to get your drug only where it needs to go?
Patrick - Exactly.
Chris - How do you persuade the nanoparticles to stick to the monocytes?
Patrick - During the monocytes targeting to the heart platelets and other type of cells, they will stick to the monocytes. So we fabricate the nanomedicines with similar sticking abilities of the platelets so once we inject them into the circulation they will stick to the monocytes and be brought to the injury sites.
Chris - So let me make sure I’ve got this correct: there are monocytes in the bloodstream and they naturally go where there’s damage. There are also bits of cells called platelets in the bloodstream which naturally stick onto monocytes, and where the monocytes go the platelets will go?
Patrick - Right.
Chris - So you’re stealing what the platelets do, putting that on your nanoparticles so your nanoparticles will stick to the monocyte and then be carted off into the heart to access the damaged area?
Patrick - Right. That's the power of what we said: we learn from mother nature.
Chris - Does it work? Do you actually get more drug going in by doing this?
Patrick - Yes, we did. We can increase 50 fold or more drugs to be delivered into the injury site.
Chris - 50 fold: that’s a lot. So if you were just to measure how much drug if you popped a pill versus if you did it the way you’re doing it, you’re saying at least 50 times more drug goes in?
Patrick: Typically, if you just simply inject a drug into the circulation, then less than 0.1 percent of a drug would be in the heart. But by the technology we’ve developed we can achieve 5 percent or even more of the drugs to be delivered to the heart.
Chris - And when you do these experiments, if you take a heart that’s been experimentally damaged by a heart attack, do you actually see a reduction in the level of damage when you use these particles that you’ve developed?
Patrick - We created animal models for heart attack and we find that by delivery of these drugs we can reduce the heart damage size by 50 percent. We can improve the cardio functions by 50 per cent as well, so such doings we can prolong the heart functions and the animal life as well.
Chris - As anyone tried to do what you’re doing before or is this a first trying to do it this way?
Patrick - This is a first.