A Revolutionary Approach to Heart Healing: The Promise of a New Patch
In a groundbreaking development, MIT engineers have crafted a flexible drug-delivery patch that could revolutionize post-heart attack treatment. This innovative patch, designed to be placed directly on the heart, aims to facilitate the healing and regeneration of cardiac tissue, offering a glimmer of hope to heart attack survivors.
The patch's unique feature lies in its ability to carry and release multiple drugs at different intervals, following a pre-programmed schedule. In a study conducted on rats, this treatment demonstrated remarkable results, reducing damaged heart tissue by an impressive 50% and significantly enhancing cardiac function. If approved for human use, this patch could be a game-changer, enabling heart attack victims to regain a substantial portion of their cardiac function, a prospect that was previously unimaginable.
Dr. Ana Jaklenec, a principal investigator at MIT's Koch Institute for Integrative Cancer Research, emphasizes the significance of this development: "When someone experiences a major heart attack, the damaged cardiac tissue struggles to regenerate, leading to a permanent loss of heart function. Our goal is to reverse this trend and empower individuals to rebuild a stronger, more resilient heart after a myocardial infarction."
The study, led by Dr. Jaklenec and Dr. Robert Langer, a renowned member of the Koch Institute, was published in Cell Biomaterials. The lead author, former MIT postdoc Erika Wang, played a pivotal role in bringing this innovative treatment to light.
The concept behind the patch revolves around programmed drug delivery. After a heart attack, many patients undergo bypass surgery, which improves blood flow but falls short of repairing the damaged cardiac tissue. The MIT team aimed to create a patch that could be applied during the surgery itself, delivering drugs over an extended period to promote tissue healing. This approach, known as phase-specific treatment, is a departure from most systems that release drugs all at once, highlighting the importance of timed delivery in synchronizing therapy with recovery.
Dr. Jaklenec elaborates on the team's vision: "We wanted to explore the possibility of delivering a precisely orchestrated therapeutic intervention to aid the heart's healing process, right at the site of damage, while the surgeon is already performing open-heart surgery."
To achieve this, the researchers adapted drug-delivery microparticles they had previously developed. These microparticles, resembling tiny coffee cups with lids, are made from a polymer called PLGA and can be sealed with a specific drug. By manipulating the molecular weight of the polymers used to form the lids, the researchers can control their degradation rate, allowing them to program the particles to release their contents at precise times. For this application, the researchers designed particles that break down and release their contents on days 1-3, 7-9, and 12-14 after implantation.
This meticulous timing enabled the researchers to devise a regimen of three drugs, each targeting a different aspect of heart healing. The first set of particles releases neuregulin-1, a growth factor that prevents cell death. At the next time point, particles release VEGF, a growth factor that promotes the formation of blood vessels surrounding the heart. The final batch of particles releases GW788388, a small molecule drug that inhibits scar tissue formation, a common complication after a heart attack.
Dr. Jaklenec highlights the importance of this carefully orchestrated sequence: "Tissue regeneration follows a meticulously timed series of steps. Dr. Wang's system delivers key components at precisely the right time, mirroring the natural healing process of the body."
The researchers embedded rows of these particles into thin sheets of a flexible hydrogel, similar in texture to a contact lens. This hydrogel, composed of biocompatible polymers alginate and PEGDA, eventually breaks down in the body. For this study, the researchers created miniature patches, only a few millimeters in size.
Dr. Wang explains the process: "We encapsulate arrays of these particles in a hydrogel patch, which we then surgically implant into the heart. In this way, we're essentially programming the treatment directly into the material."
The results of testing these patches on spheres of heart tissue, which included cardiomyocytes generated from induced pluripotent stem cells, were encouraging. The patches promoted blood vessel growth, increased cell survival, and reduced fibrosis, a common complication after a heart attack.
In tests on a rat model of heart attack, the researchers observed significant improvements following treatment with the patch. Compared to untreated animals or those receiving the same drugs via IV injection, the animals treated with the patch exhibited a 33% higher survival rate, a 50% reduction in damaged tissue, and a substantial increase in cardiac output.
The researchers also demonstrated that the patches would gradually dissolve over time, forming a thin layer that did not disrupt the heart's mechanical function.
Dr. Langer underscores the potential impact of this innovation: "This approach, combining drug delivery and biomaterials, opens up new avenues for treating patients."
While neuregulin-1 and VEGF have been tested in clinical trials for heart conditions, GW788388 has only been explored in animal models. The researchers now aim to test their patches in additional animal models, with the ultimate goal of conducting a clinical trial in the future.
The current version of the patch requires surgical implantation, but the researchers are exploring the possibility of incorporating these microparticles into stents, which could be inserted into arteries to deliver drugs on a programmed schedule, offering a less invasive treatment option.
This innovative patch represents a significant step forward in the field of cardiac care, offering a glimmer of hope to heart attack survivors and their loved ones.
