Dr. David Macpherson: Illness from vaping highly predictable

The explosion of “vaping” myriads of flavors and substances has quickly led to life-threatening disease and death in young people. A brief description of how our body staves off toxins shows why this recent outbreak was predictable.

All life forms live in a world of toxins — mostly invisible stuff that might eat away at our cores. Humans are no different, and over hundreds of thousands of years, we have honed defenses to protect us from injury and early demise. Our systems of protection are many, though we seem most susceptible when we inhale.

The nasty stuff can enter our body in three ways. First, when we eat something, toxins face a gauntlet of defenses before they enter our bloodstream, the superhighway that might carry it anywhere and cause injury. Once in our gut, toxins face caustic acids that break them into harmless molecules or generate signals that we’ve consumed something bad and force us to vomit or pass it through so quickly it has no time to be absorbed. If the vomiting/diarrhea signals aren’t engaged, the stuff faces several cell layers through which it must pass before entering our bloodstream. Some cells in our gut eat it and break it down. But even if it gets by this barrier, most blood from our gut passes through the liver before entering our regular circulation, and the liver picks out the toxins quite efficiently. The lines of defense to protect us from harm from what we eat are many.

The second means of entry is through our skin, which is composed of many layers of cells. The toxins that touch our skin must pass through these layers that include cells that pick out and neutralize the bad stuff before it gets to the blood. When this layer of defense is violated, — think ticks carrying the Lyme organism burrowing beneath our skin to find a blood vessel or addicts probing with virus-laden needles to inject a vein — the protective layer has been breached and disease happens. Those who manufacture or deliver medicine or vaccinations through needles work tirelessly to ensure the needles are sterile and clean of toxins. Overall, our skin works quite well to protect us.

Perhaps our most vulnerable mode of entry of toxins is through inhalation. While our design includes tiny hairs (cilia) in the lining of the larger lung tubes to catch large things, most of the air we inhale, including the harmful stuff, goes directly to our lungs, directly to critical cells. The design is purposeful in that we must have adequate oxygen in our blood to live. Even a short period of low blood oxygen leads to unconsciousness.

To get from the lungs to the blood, oxygen passes through two tiny cell walls, one from the lung side, the other from the blood side. Inhaled toxins can take the same path. There is no protective barrier and little chance for other cells to identify and gobble up toxins before they cause damage to the critically important cells that handle oxygen for us. And once the toxin enters the blood stream of the lungs, it quickly goes to the heart and from there, very quickly, almost everywhere in the body. Although there are other cells that rush around in our circulation and grab some of the poisons, no organ like the liver stands in the toxins’ way to catch them before they might cause damage elsewhere. Though the oxygenation design is incredibly effective, at the same time it’s an enormous vulnerability if we choose to inhale substances.

When humans heat up stuff (like cigarettes or vaping flavors) and suck the smoke or heated vapor into their lungs, they are hoping whatever breakdown products won’t cause trouble, even though there is almost nothing in their way to prevent injury either to the lung cells themselves or distant organs. Sometimes the damage shows up quickly and sometimes only after years of exposure do the consequences become apparent.

But make no mistake: Products designed to be inhaled are potential disasters for humans. They should never be sold unless extremely rigorous testing has proven no harm.

So, it is really not surprising that the vaping fad has quickly proven to be harmful. We’re learning now about short-term consequences. It’s too early to understand long-term effects. Even if we learn which vaping products result in immediate injury, why would we assume later disease, like cancer or emphysema or other forms of lung disease, wouldn’t occur?

Each day — yes, day — over 1,300 people in the U.S. die from tobacco-related disease.We were late to control smoldering tobacco leaves from the market. We shouldn’t make the same mistake with vaping products.

David Macpherson, MD, MPH, is a retired professor of medicine from the University of Pittsburgh and former chief medical officer for a region of the Veterans Administration.