You’re already familiar with the most common factors of heart disease: high blood pressure, obesity, inactivity, and others. But many people — patients and clinicians alike — don’t realize that immune activity in the heart itself plays a major role in the disease’s development and progression.
Specifically, cardiac mast cells, which are embedded immune cells that regulate vessel function and tissue repair. In a healthy state, these cells serve a protective role in the heart. But when chronically activated, they may contribute to fibrosis, arrhythmias, and heart disease.
There’s still much we don’t know about the cardiac mast cell, but this is a guide to what we do.
What are cardiac mast cells?
Mast cells are immune cells created by your bone marrow, then circulated through the blood to your tissues (including your heart). They’re similar, but not the same, as basophils, which are a type of white blood cell. They also serve a similar function: protecting your body from pathogens, venom, and other foreign particles.
Cardiac mast cells have a similar focus on combating foreign particles. They use surface proteins as antennas to identify metabolic and immune changes. When the cells pick up on a problem, they generate what’s called vasoactive and proinflammatory mediators: hormones that affect the elasticity of your vessels. More on this later.
Cardiac mast cells, or CMCs, release mediators in response to:
- Mechanical stress on heart tissue
- Reduced oxygen delivery (ischemia and hypoxia)
- Inflammation within your heart tissue
- Stress hormones such as norepinephrine and endothelin-1
- Hyperglycemia and insulin resistance
Even a small change to your metabolic health can trigger a large immune response from your cardiac mast cells.
This can be a good and bad thing, depending on your state of health and the severity of your issue.
How cardiac mast cells help
CMCs are similar to LDL cholesterol in the sense that they act as first responders in the body.
When activated for a short-term issue, CMCs can help:
- Attract repair cells to damaged heart tissue
- Relax the vessels and improve blood flow
- Support tissue repair after minor damage
How cardiac mast cells hurt
When metabolic disruption continues for a long time, your mast cells remain active and release large amounts of hormones. This ultimately ‘remodels’ the heart in some very unhealthy ways. As you might imagine, this can wreak havoc on your body.
Chronically activated CMCs can:
- Cause additional inflammation by releasing histamine into affected areas
- Contribute to heart scarring, also called fibrosis, which makes the heart stiff
- Affect heart rhythm, or arrhythmia, which can affect the pumping efficiency of your heart
Sustained over a period of years or even decades, mast cells can greatly contribute to heart disease development and progression. And keep in mind mast cells tend to become more numerous in older hearts. The more activation factors are present, and the more mast cells you have, the greater (and potentially more detrimental) the response.
As one study suggests, overactive CMCs are one of the primary causes of small vessel/microvascular disease. In their words, “mast cells [are] critical players of cardiac microvessel disease and diastolic dysfunction.”
Another study found that CMCs triggered over long periods of time “worsen or precipitate CAD.”
To summarize: the mediators produced by cardiac mast cells can be helpful in small or controlled doses. But once they become overactive, they substantially increase your risk for heart disease.
Mediating the effects of cardiac mast cells
Cardiac mast cells aren’t ‘bad’ by default. But when chronically agitated, they can accelerate inflammation, scarring, and other heart dysfunctions.
The good news is, it’s possible to rein in your chronic response. Doing so early may help to prevent or reduce the effects of heart disease.
Below are a few suggestions for getting your CMCs under control:
Prioritize exercise
Physical activity is good for your heart in general. But for hyperactive CMCs, it’s also a cost-effective activator mediator.
Regular aerobic exercise may help to reduce cardiac mast cell activation, which ultimately limits conditions like fibrosis.
Coupled with resistance exercises and HIIT, you can help strengthen the heart, reduce CMC response, and build metabolically healthy tissue.
Reduce stress where able
As mentioned, high levels of stress can increase mast cell activity. It can also contribute to oxidative stress.
From a physiological perspective, do your best to avoid activities that induce oxidative stress such as:
- High alcohol consumption
- Smoking
- Heavy pollution exposure
From a psychological perspective, look for healthy coping mechanisms around everyday work, financial, or social stressors. That’s because hormones like cortisol (a.k.a. ‘the stress hormone’) can prime mast cells to be more reactive.
I realize you can’t eliminate all sources of stress, but there are still a few ways to mitigate your response. You can also get more specific advice in my guide to managing workplace stress.
Adjust your diet
I could write (quite literally) an entire book on this topic. But out of respect for your time, I’ll highlight the important bullets here.
A diet that avoids over-activating your CMCs is also a metabolically healthy one. It means:
- Prioritizing high-quality protein. I cover some options in my guide to the best meat to eat for your metabolic health.
- Avoiding sugar. This includes fake sugars that disrupt metabolic health.
- Moderating carbohydrates. Processed carbs greatly contribute to bodily inflammation.
- Eating more omega-3s. Studies show this may help reduce mast cell-mediated inflammation.
- Focusing on animal fats. I recommend tallow, lard, butter, and schmalz.
I get much further into the weeds on this in my book: Stay Off My Operating Table®.
Address underlying disease
Having an underlying chronic or autoimmune disease can greatly contribute to mast cell activation. As one study summarizes, “there is abundant evidence that mast cells are active participants in events that mediate tissue damage in autoimmune disease.” Another finds that chronic CMC activation may stem from “having a chronic disease.”
Contrary to what you may have been told, many chronic diseases are addressable and even curable. It is possible to control obesity, hypertension, and diabetes with lifestyle changes and new dietary habits. Remember: medications aren’t the only way to treat chronic disease.
Taking action on these today could mean a longer healthspan.
Biomarkers when checking for CMC activation
There’s no single clinical test that directly measures CMC activation, but there are several biomarkers that may indicate a problem.
You should run a complete metabolic panel, or CMP, and look for:
- High blood sugar: Below 100mg/dL while fasting.
- Obesity: Waist circumference under 40 inches for men, and under 35 inches for women.
- Insulin resistance: Usually indicated by a HOMA-IR value of 2.5.
You can also use a few other factors to determine if you’re metabolically unhealthy.
Calculate this in 15 minutes or less using my free metabolic health quiz.
