A heart attack seems like a one-way event: a blockage, injured muscle, and damage that stays. Yet the heart has a built-in repair system, and scientists thought they knew how it worked. A new study says they had the source wrong. The same research team then found a way to strengthen that repair in animals, with clear effects on scarring and heart function. Here is what they discovered, and why it could matter for people who live with the aftermath of a heart attack.
The Heart’s Emergency Response to a Blockage
A heart attack happens when a coronary artery, one of the vessels feeding the heart muscle, becomes blocked. Without that blood supply, the muscle loses the oxygen and nutrients it needs to keep working, and the tissue starts to die.
Your body doesn’t wait for treatment. It starts its own emergency response right away. The heart widens nearby arteries to push more blood through them, and it also grows new vessels that carry blood around the blockage. These new vessels are called coronary collateral arteries. Think of them as natural detours: blood reaches the starved area by a different route, and outcomes after a heart attack improve.
In most patients, though, this response is too slow or too weak to prevent damage. By the time the collaterals are working, part of the muscle is often already injured.
That raises a practical question. If we could help the heart build these detours faster or stronger, we could protect more tissue. And to do that, we first need to know exactly how the heart builds them.
For a long time, the accepted answer was that cells from existing arteries break away, migrate, and reassemble into new arteries. A research team led by Mingjun Zhang and Bin Zhou at the Chinese Academy of Sciences tested that idea. Their findings, published in Science in August 2026, point somewhere else.
Capillaries, Not Arteries, Do the Building
To settle the question, the researchers needed to see where the cells in new collateral arteries actually came from. Earlier studies relied on a cell marker that turned out to be less specific than assumed, so some cells were likely misidentified. Zhang’s team used a more precise method instead: dual genetic lineage tracing in mice. It labels the cells lining the large arteries and the cells lining the capillaries at the same time, in the same heart, so you can tell which group ends up in a new vessel.
Capillaries are the tiny vessels that connect arteries to veins. They are far smaller than the arteries that feed them, and nobody expected them to be the main source of new collaterals.
After a heart attack in the mice, every new collateral artery contained cells that started out in capillaries. Existing arteries contributed only a small share. The bulk of each new vessel came from capillary cells that had converted into artery-type cells, a process called arterialization. The heart was not rebuilding arteries from artery parts. It was turning capillaries into arteries.
This is not a new trick for the heart. The same process builds small coronary artery branches in newborn mice while the heart is still developing. The adult heart appears to reuse that program when it is injured.
The team also checked whether this conversion matters. When they selectively blocked capillary-derived collaterals from forming, the mice had larger scars and worse heart function. So these vessels do real work in repair.
With the source identified, the next step was finding what drives the conversion, and whether it can be boosted.
The Right Signal at the Right Time
Once the team knew capillaries were the source, they looked for what drives the conversion. The answer was VEGF-A, a signaling protein that promotes blood vessel growth. Inside capillary cells, VEGF-A sets off a chain of molecular steps (involving proteins called YY1, SETD1A, and HES1) that pushes the cell to become an artery-type cell. When the researchers interrupted that chain, collateral formation dropped. In human vessel-lining cells grown from stem cells, VEGF-A raised the level of YY1, which suggests the same pathway may operate in people.
Next, they tested whether adding more VEGF-A could produce more collaterals. They injected modified messenger RNA (mRNA) carrying the instructions for VEGF-A into the heart wall of mice. The cells read those instructions and make the protein for a short time, then stop.
That timing matters. Prolonged VEGF signaling is known to produce leaky, immature vessels. A short pulse gives new vessels time to mature into sturdy ones.
The treated hearts showed clear gains:
- More capillary-derived collateral vessels
- Better blood flow around the injured area
- Smaller scars
- Stronger pumping
The researchers also noted that moderate VEGF-A supplementation may restore circulation in the smallest vessels of the heart, which points to the vascular environment around the injury as a useful treatment target.
Earlier attempts to use VEGF for heart disease ran into the problem of how to deliver it safely and in the right amount. A brief, controlled burst addresses that directly.
Everything described so far comes from mice, and that shapes what we can and can’t say about patients.
Boosting the Heartβs Own Repair System After a Heart Attack
Right now, nothing changes in the treatment you would receive. This work is in mice, and no one has tested a VEGF-A treatment in people after a heart attack. The researchers are also clear that more work is needed before anyone can say whether it would be safe or effective in humans.
Still, there is good reason to take the finding seriously. The heart attack response in human hearts is likely to follow a similar pattern, and the human vessel-lining cells in the lab responded to VEGF-A the same way the mouse cells did. Now that the mechanism is mapped, researchers can work out which steps could be targeted with drugs.
Here is why it matters. In the US, more than 90 percent of patients who reach the hospital after a heart attack now survive. That is a major success. But survival is not the end of the story. Many of these patients are left with scarred, weakened heart muscle, and that damage leads to other cardiovascular problems later, including heart failure.
The goal of this research is to address that gap. A treatment given soon after a heart attack that increases blood flow around the injury and reduces scarring could mean less permanent damage for the people who survive.
The approach also works with the body’s own repair system rather than replacing it. Your heart already converts capillaries into new arteries after an attack. The aim would be to make that natural response faster and more effective.
This is early-stage science, and it will take time to reach patients. But it points to a specific target for the first time, and that is how new heart treatments get started.
My Personal RX on Supporting Your Heart Every Day
A heart attack can leave lasting damage, so protecting your heart before anything happens matters. You don’t need big changes. Small, steady habits add up. If you’re already recovering from a cardiac event, follow your cardiologist’s plan first and use these tips alongside it. Here are my personal tips.
- Know Your Numbers:Β Get your blood pressure, cholesterol, and blood sugar checked at least once a year. You can’t fix what you haven’t measured.
- Walk Daily:Β Aim for 30 minutes of brisk walking most days. Split it into shorter walks if that’s easier.
- Eat More Plants:Β Fill half your plate with vegetables, fruit, beans, and whole grains. Cut back on processed meats and packaged snacks.
- Get Your Omega-3s:Β Omega-3 Fish OilΒ supports heart health and cognitive function, especially if you rarely eat fatty fish.
- Fill Nutrient Gaps:Β After 40, diet alone often falls short. MyΒ Core Four BundleΒ covers omega-3, calcium and magnesium, vitamin D3 and K2, and a gut-brain probiotic.
- Protect Your Sleep:Β Aim for seven to nine hours. Keep a fixed bedtime and screens out of the bedroom.
- Manage Stress:Β Try ten minutes of slow breathing or stretching daily. Chronic stress keeps your body on high alert.
- Move Through the Day:Β If you sit for work, stand and stretch every hour. Long stretches of sitting add up.
- Act on Warning Signs:Β Chest pressure, shortness of breath, or pain spreading to the arm or jaw need emergency care. Call right away.
- Follow a Whole-Health Plan:Β My guide,Β Dr. Partha Nandi’s Protocol for Optimizing Your Health & Wellbeing, puts diet, movement, sleep, and stress habits into one plan.
Sources:
- Nield, D. (2026, August 22).Β Your Heart Can Actually Build Its Own Bypass After a Heart Attack. ScienceAlert. https://www.sciencealert.com/your-heart-can-actually-build-its-own-bypass-after-a-heart-attack
- Zhang, M., Han, M., Hou, Y., Liu, Z., Wang, Y., Huang, X., Ho, C. K., Qu, H., Wang, Q.-D., Ma, X., Lui, K. O., & Zhou, B. (2026). Tracing the origins of de novo coronary collateral formation in cardiac repair.Β Science,Β 393(6813). https://doi.org/10.1126/science.ady3027
