The Common Origins of Heart Artery Disease and Lung Cancer

You've Come a Long Way Baby!

You've Come a Long Way Baby!

You’ve come a long way baby! Do you remember that commercial for a brand of cigarettes for women? It is true, but not in a good way. The risks for lung cancer are about equal in men and women today. Women who smoke are a bit more likely to have heart artery disease than men. We can detect both lung cancer and heart artery disease with a simple screening test. This is especially important for female smokers because their heart artery disease is often missed.

In the last post, we discussed screening for lung cancer with a low dose CT scan. Patients who have calcium in their heart arteries on that test have a high risk for a heart attack or sudden death. Heart artery disease kills more Americans than any other illness. Lung cancer takes more American lives than any other malignancy. Smoking cigarettes causes lung cancer and heart artery disease. Low dose CT scans uncover both diseases at a time when catastrophe can be avoided with simple treatments. Now we understand the common origins of these two diseases well enough that we can treat them more effectively. The best treatment is prevention.

The diagram below provides a simple explanation. Don’t be spooked by it. If you can learn “quiero un taco” to say “I want a taco” in Spanish, you can learn this. It is just the language of life and disease. The arrows mean the box at the base activates or switches on the box at the point of the arrow. For example, in the center of the diagram, oxidants switch on EGFR (the epidermal growth factor receptor). The other symbol that looks like a T means the box at the base switches off the other box at the end. For example, the medicines in the green boxes switch off the enzymes and hormones that increase oxidant production.

This simple diagram explains how smoking, abdominal fat, and aging make both heart artery disease and lung cancer more likely. EGFR is the purple box in the middle of the slide and is a central player in both diseases. Cigarette smoke contains ten to the fifteenth oxidative particles per puff. These oxidants persistently activate EGFR to cause the wild growth of lung cells in cancer and the death of lung cells in emphysema. They also cause the arteries to become inflamed and thicker while causing the heart to get bigger.

The three red boxes at the top are switched on by abdominal fat and they cause increased oxidant production. That adds to the damage caused by the oxidants in cigarette smoke and that is how these diseases are tied together. As you can easily see, persistently switching on EGFR switches on mTOR and switches off AMPK. mTOR is the mechanistic target of rapamycin. Rapamycin is an antibiotic discovered on Easter Island. Rapamycin in modern heart artery stents slowly leaks out to inhibits inflammation and scar formation so that the stent stays open longer.

mTOR is a master metabolic genetic switch that coordinates food supply with growth in the fetus and child. Let’s call it the growth switch. It becomes much less active in healthy young adults. It is reactivated later in life by food and cigarette smoke to cause uncontrolled cell growth in cancer. It also causes the arteries to get thicker and the heart to get bigger leading to heart artery disease, high blood pressure, and heart failure.

If there is no food for the infant and child, mTOR is switched off and AMPK is switched on. These switches are paired. When one is on the other is off. AMPK is the survival switch. It switches off genes that are involved in synthesis and switches on genes that pull calories from fat and muscles to provide enough energy so that the fetus or child survives until food is available. These switches are perfectly coordinated in the fetus and child to support perfect health. In older adults, abdominal fat, smoking, and eating switch on mTOR and switch off AMPK to cause heart disease, lung cancer and more rapid aging.

So, the path to better health is clear. Stopping smoking, exercise, intermittent fasting, and staying thin switch off mTOR and switch on AMPK. At the top of the diagram, lisinopril, losartan, statins, spironolactone, and eplerenone block oxidant production to do the same thing. Metformin directly switches off mTOR and switches on AMPK. Jardiance and other drugs in that class provide a similar benefit whether you are diabetic or not. When you combine these interventions it slows aging and delays your likelihood of developing chronic diseases like lung cancer and heart artery disease. You can have a longer, healthier life at lower cost now.