How Cigarette Smoke Causes COPD To Hang On After Smoking Ends

How Cigarette Smoke Causes COPD To Hang On After Smoking Ends
Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the United States.
 Image by StockSnap 

Smoking is the most common cause of chronic obstructive pulmonary disease, an often fatal respiratory condition that afflicts millions of Americans. But for many patients living with COPD, stopping smoking isn’t the end of the battle.

Cigarette smoke is a complex mixture of gases, chemicals and even bacteria. When it enters the lungs, it generates an inflammatory response much like pneumonia.

Inflammatory cells normally clear from the lungs when an infection ends or a patient quits smoking, but in patients with COPD, these cells may persist for years. Destructive enzymes produced by these cells – intended to destroy bacteria – cause progressive lung damage and respiratory failure characteristic of COPD.

It’s been a mystery why these cells continue triggering inflammation in the lungs after people stop smoking. Now, new research indicates a defect in the immune system induced by cigarette smoke is to blame. Cigarette smoke reprograms the cells lining the airways, making the lungs of COPD patients who have quit smoking more susceptible to bacterial invasion.

Good fences make good neighbors

The lungs are continuously bombarded by inhaled bacteria and other irritants. At the same time, they are tasked with getting oxygen into the bloodstream, so they can’t have an impermeable physical barrier like skin.

To solve this dilemma, the lungs have developed a multi-pronged defense system. A key component of this system is an antibody called secretory IgA. These antibodies latch on to bacteria to prevent them from invading the lungs. Secretory IgA doesn’t directly kill microbes, but it prevents them from triggering a damaging immune response before they can be cleared by other mechanisms.

Illustration of how SIgA operates in the lining of a person's airway. Our airways are lined with a layer of cells called the airway epithelium. When bacteria and other germs are inhaled, one way the airway epithelium protects itself is by transporting secretory immunoglobulin A (SIgA) to the airway surface. SIgA attaches to bacteria to prevent them from invading and causing inflammation. SIgA is made by plasma cells beneath the airway epithelium and transported by polymeric immunoglobulin receptors. People with COPD lack SIgA in their airways, which allows bacterial invasion, inflammation and lung damage. Dayana Espinoza/Vanderbilt University, CC BY-ND

In patients with COPD, lower levels of the polymeric immunoglobulin receptor and secretory IgA allow bacteria easier access to the airway surface, triggering an inflammatory response that persists after the patient quits smoking.

Mice that have been genetically manipulated to lack secretory IgA also develop inflammation and a pattern of lung damage resembling patients with COPD. Antibiotics can prevent them from developing lung disease, suggesting bacteria cause continued inflammation after smoking ends.

The double-edged sword of anti-inflammatories

Since inflammation is central to COPD, it makes sense that anti-inflammatory therapies might be beneficial. However, patients with COPD are also susceptible to lung infections, and anti-inflammatories run the risk of deactivating the body’s natural defenses against infection. The threat is more than theoretical: A clinical trial studying an anti-inflammatory drug called rituximab was stopped early due to an increased rate of pulmonary infections.

Many antibiotics also have serious side effects when taken chronically, and prolonged use might encourage growth of bacteria resistant to these drugs.

How Cigarette Smoke Causes Copd To Hang On After Smoking Ends
National Heart, Lung and Blood Institute

A new target for treating COPD?

While studying mice lacking secretory IgA, our research team at Vanderbilt University Medical Center and colleagues at the University of Florida recently found these mice have increased numbers of a relatively uncommon type of cell called monocyte-derived dendritic cells, or moDCs, in the lungs.

Dendritic cells don’t directly destroy bacteria, but they ring the alarm that a bacterial infection is brewing and coordinate the subsequent immune response. Unlike typical dendritic cells, moDCs begin their lives as a different cell type, called a monocyte. But when chronic inflammation sets in, they can become a type of dendritic cell.

We showed that in mice genetically engineered to lack secretory IgA, moDCs activate T lymphocytes – white blood cells that fight off viruses and can destroy cells in the process – and those T lymphocytes in turn damage the lungs. These data implied that moDCs might also coordinate a pathologic immune response in patients with COPD who also lack secretory IgA in the airways.

Because moDCs weren’t known to exist in human lungs, we used a cutting-edge technique called mass cytometry to detect them. It allows us to distinguish moDCs from other cell types that appear very similar under a microscope.

Like secretory IgA-deficient mice, we found that human COPD patients lacking secretory IgA had increased numbers of moDCs in their lungs. Together, these data suggest that loss of secretory IgA makes the airways more susceptible to bacterial invasion, which activates moDCs to drive ongoing lung inflammation. Therefore, targeting moDCs through medical treatments might block inflammation and lung damage in patients with COPD.

New drugs are urgently needed for COPD

There are still many questions to answer, including how best to target moDCs. It also remains to be seen whether such a strategy would compromise the ability of COPD patients to defend against infection.

However, for a disease as common and debilitating as COPD, potential new drug targets come as a breath of fresh air.

COPD is the fourth leading cause of death in the U.S. and the third leading cause of death worldwide. While many drugs are available to decrease symptoms and hospitalization rates in patients with COPD, none has been proven to prolong life.

Most patients with COPD don’t die from it, but those who live with COPD suffer from chronic breathlessness which negatively impacts their quality of life. The burden of COPD is felt not just by individual patients, but by families, workplaces and economies.

Though cigarette smoking rates are declining in the United States, they are increasing in many other countries, making COPD a global health issue.The Conversation

About the Author

Bradley Richmond, Assistant Professor of Medicine, Vanderbilt University

This article is republished from The Conversation under a Creative Commons license. Read the original article.


Recommended Books: Health

Fresh Fruit CleanseFresh Fruit Cleanse: Detox, Lose Weight and Restore Your Health with Nature's Most Delicious Foods [Paperback] by Leanne Hall.
Lose weight and feel vibrantly healthy while clearing your body of toxins. Fresh Fruit Cleanse offers everything you need for an easy and powerful detox, including day-by-day programs, mouth-watering recipes, and advice for transitioning off the cleanse.
Click here for more info and/or to order this book on Amazon.

Thrive FoodsThrive Foods: 200 Plant-Based Recipes for Peak Health [Paperback] by Brendan Brazier.
Building upon the stress-reducing, health-boosting nutritional philosophy introduced in his acclaimed vegan nutrition guide Thrive, professional Ironman triathlete Brendan Brazier now turns his attention to your dinner plate (breakfast bowl and lunch tray too).
Click here for more info and/or to order this book on Amazon.

Death by Medicine by Gary NullDeath by Medicine by Gary Null, Martin Feldman, Debora Rasio and Carolyn Dean
The medical environment has become a labyrinth of interlocking corporate, hospital, and governmental boards of directors, infiltrated by the drug companies. The most toxic substances are often approved first, while milder and more natural alternatives are ignored for financial reasons. It's death by medicine.
Click here for more info and/or to order this book on Amazon.


You May Also Like

AVAILABLE LANGUAGES

enafarzh-CNzh-TWdanltlfifrdeeliwhihuiditjakomsnofaplptroruesswsvthtrukurvi

INNERSELF VOICES

happy woman 's face
How To Experience A Mystical State of Consciousness
by Ora Nadrich
Whatever it is we seek pleasure from, relying on external things to give us the high or a feeling…
a blurred clock expanding over a starry background
Horoscope Current Week: December 6 - 12, 2021
by Pam Younghans
This weekly astrological journal is based on planetary influences, and offers perspectives and…
12 05 from rigidity to change 647528 complete
From Rigidity to Change
by Marie T. Russell, InnerSelf.com
In order for things, or people, to change they need to be flexible. A willow tree bends in the wind…
man and dog in front of giant sequoia trees in California
The Art of Constant Wonder: Thank you, Life, for this day
by Pierre Pradervand
One of the greatest secrets of life is to know how to constantly marvel at existence and at the…
Photo: Total Solar Eclipse on August 21, 2017.
Horoscope: Week of November 29 - December 5, 2021
by Pam Younghans
This weekly astrological journal is based on planetary influences, and offers perspectives and…
young boy looking through binoculars
The Power of Five: Five Weeks, Five Months, Five Years
by Shelly Tygielski
At times, we have to let go of what is to make room for what will be. Of course, the very idea of…
man eating fast food
It's Not About the Food: Overeating, Addictions, and Emotions
by Jude Bijou
What if I told you a new diet called the "It's Not About the Food" is gaining popularity and…
woman dancing in the middle of an empty highway with a city skyline in the background
Having the Courage to Be True to Ourselves
by Marie T. Russell, InnerSelf.com
Each one of us is a unique individual, and thus it seems to follow that each one of us has a…
Who Will You Be This Year?
Who Will You Be This Year?
by Alan Cohen
As we set out on the great adventure called 2021, many of us have lots of questions about what the…
There Is A Brighter Way: Freeing The Creativity Within
There Is A Brighter Way: Freeing The Creativity Within
by Diana Rowan
Knowing what I know now fires me up with enthusiasm to share this truth: there is a brighter way.…
Three Big Bangs: Looking Back To See Forward
Three Big Bangs: Looking Back to See Forward, to Wake Up and to Change
by Ervin Laszlo
We know that a transformation of global dimensions has already started, and we know that its…

Selected for InnerSelf Magazine

MOST READ

How Living On The Coast Is Linked To Poor Health
How Living On The Coast Is Linked To Poor Health
by Jackie Cassell, Professor of Primary Care Epidemiology, Honorary Consultant in Public Health, Brighton and Sussex Medical School
The precarious economies of many traditional seaside towns have declined still further since the…
The Most Common Issues for Earth Angels: Love, Fear, and Trust
The Most Common Issues for Earth Angels: Love, Fear, and Trust
by Sonja Grace
As you experience being an earth angel, you will discover that the path of service is riddled with…
How Can I Know What's Best For Me?
How Can I Know What's Best For Me?
by Barbara Berger
One of the biggest things I've discovered working with clients everyday is how extremely difficult…
Honesty: The Only Hope for New Relationships
Honesty: The Only Hope for New Relationships
by Susan Campbell, Ph.D.
According to most of the singles I have met in my travels, the typical dating situation is fraught…
An Astrologer introduces the Nine Dangers of Astrology
An Astrologer introduces the Nine Dangers of Astrology
by Tracy Marks
Astrology is a powerful art, capable of enhancing our lives by enabling us to understand our own…
Giving Up All Hope Could Be Beneficial For You
Giving Up All Hope Could Be Beneficial For You
by Jude Bijou, M.A., M.F.T.
If you're waiting for a change and frustrated it's not happening, maybe it would be beneficial to…
Chakra Healing Therapy: Dancing toward the Inner Champion
Chakra Healing Therapy: Dancing toward the Inner Champion
by Glen Park
Flamenco dancing is a delight to watch. A good flamenco dancer exudes an exuberant self-confidence…
Taking A Step Toward Peace by Changing Our Relationship With Thought
Stepping Toward Peace by Changing Our Relationship With Thought
by John Ptacek
We spend our lives immersed in a flood of thoughts, unaware that another dimension of consciousness…

New Attitudes - New Possibilities

InnerSelf.comClimateImpactNews.com | InnerPower.net
MightyNatural.com | WholisticPolitics.com | InnerSelf Market
Copyright ©1985 - 2021 InnerSelf Publications. All Rights Reserved.