Lung

Lungs enlist immune cells to fight infections in capillaries

neutrophils
ON TRACK Neutrophils (red) crawl along the walls of capillaries in a mouse lung (tracks shown in blue). In mice deficient in a key protein, these immune cells couldn’t move as far (left) as those in mice that had the protein (right).

Immune cells in the lungs provide a rapid counterattack to bloodstream infections, a new study in mice finds. This surprising discovery pegs the lungs as a major pillar in the body’s defense during these dangerous infections, the researchers say.

“No one would have guessed the lung would provide such an immediate and strong host defense system,” says Bryan Yipp, an immunologist at the University of Calgary in Canada. Yipp and his colleagues report their findings online April 28 in Science Immunology.

The work may offer ways to target and adjust our own immune defense system for infections, says Yipp. “Currently, we only try to kill the bacteria, but we are running out of antibiotics because of resistance.”

The research uncovers some of the mechanisms that drive the rapid activation of neutrophils, says immunologist Andrew Gelman of Washington University School of Medicine in St. Louis. “This is critical in removing bacteria from sequestered spaces in the lung,” he says.

Generally, clearing bacteria out of the bloodstream falls to macrophages that reside in the liver and the spleen. But macrophages aren’t found in vessels of the lungs. So the lungs’ blood vessel network gives pathogens a place to hide and escape the body’s usual removal efforts.

In…

Concerns explode over new health risks of vaping

exploding atomizer
exploding atomizer

Vaping is not risk-free, especially for kids and teens. A host of new studies have now uncovered worrisome health concerns. For instance, the atomizer shown here can make vapors hotter and riskier to health.

When Irfan Rahman talked to young vapers, some complained of bleeding mouths and throats. And these bloody sores seemed slow to heal. Such reports concerned this toxicologist at the University of Rochester in New York. So he decided to investigate what the vapors inhaled from electronic cigarettes might be doing to mouth cells.

Last October, his team showed those vapors inflame mouth cells in ways that could potentially promote gum disease. That gum damage can destroy the tissues that hold teeth in place. So severe gum disease could lead to tooth loss.

But that’s hardly the end of it.

Vapers inhale those same gases and particles into their lungs. Rahman wondered what effects those vapors might have on cells there. One gauge would be to test how long any lung-cell damage took to heal. And his latest data confirm that e-cigarette vapors also make it hard for lung cells to repair damage.

Students as young as 12 or 13 are now more likely to vape than to smoke. Many are under the impression that because e-cigs don’t contain tobacco, they pose little risk to health. Wrong.

Over the past few months, research has turned up evidence that vaping can pose many brand new risks. The vapors mess with immunity, some studies show. “Smoker’s cough” and bloody sores have begun showing up in teen vapers. The hotter a vaped liquid gets, the harsher its effects on human cells. And a relatively new vaping behavior called “dripping” ups the heat. This threatens to intensify a teen’s risks from those vapors.

Some new data even suggest that e-cig vapors may contain cancer-causing chemicals.

“There are a lot of potentially harmful substances in e-cigarettes. If you’re a teen with your whole life in front of you, why take that risk?” asks Rob McConnell. He’s an internal medicine specialist at the University of Southern California (USC) in Los Angeles.

The newly emerging data suggest that adolescents ignore these risks at their peril.

Cells in the body face constant damage from foreign substances, infections and injury. Most times, nothing bad happens to their host. That’s because the body has a system in place to heal itself. Most major organs have special cells — fibroblasts (FY-broh-blasts) — that repair damaged or injured tissue.

Fibroblasts make up the connective tissues that keep organs in place. But when injured, these cells morph into wound-healers. “If you cut your hand, fibroblasts are the guys that are going to come in and help heal it,” explains Rahman.

In their wound-healing form, fibroblasts at the edges of a cut will shrink. This causes the wound to close up. This squeezing or contraction of the skin takes a lot of energy. Fortunately, fibroblasts are powered by cellular engines. Called mitochondria (My-toh-KON-dree-uh), these tiny powerhouses turn food (sugar) into fuel.

fibroblast cells
Fibroblast cells (such as those seen here) repair damaged or injured tissues. The cells’ nuclei are colored blue. Their mitochondria are red. Filaments (green) help the fibroblast contract.

In the lab, Rahman and his colleagues grew lung fibroblasts in Petri dishes. Then they cut into the community of growing cells to mimic a wound. Afterward, they exposed the growing cells to e-cigarette vapors.

As expected, the fibroblasts morphed into wound-healing cells. But unexpectedly, they didn’t close up the cut. Curious, Rahman looked more closely at the cellular machinery. Some mitochondria had been destroyed. The fibroblasts simply had run out of the energy they needed before they could successfully squeeze the wound closed.

Rahman’s team described its findings March 3 in Scientific Reports.

It’s not clear yet if the fibroblast damage that Rahman showed in the lab signals that wounds will heal more slowly in people who vape. After all, in the lab, scientists can manipulate one variable at a time while holding other factors constant. But in the body, many processes will be at work all at once. This can make it harder to tease out whether such lab tests mimic well what would happen to an otherwise healthy person.

And that’s why Rahman now hopes to compare rates of wound healing in people who vape to rates in those who don’t. For now, however, he’s worried that what he saw in the lab may indeed mimic risks to people.

Smoker’s cough becomes vaper’s cough?

Inhaling pollution can irritate the lungs. And when the assaulting particles are breathed in regularly, the lungs tend to respond by triggering a cough that won’t go away, explains McConnell at USC. He has been studying the effects of air pollution in kids. Inhaling irritating particles or gases may lead to bronchitis (Bron-KY-tis). That’s when the airways that channel oxygen to the lungs become irritated and inflamed.

bronchitis girl
Researchers have found evidence that vaping can irritate the lungs and lead to chronic wheezing and coughs, a condition known as bronchitis.

Bronchitis may cause wheezing, too, and coughs that bring up thick mucus known as phlegm (FLEM). The germs that cause colds, flu and bacterial infections can sometimes trigger bronchitis. So can breathing in heavily polluted air, tobacco smoke or certain chemical fumes.

When these symptoms don’t go away, the bronchitis is called chronic (KRON-ik). And cigarette smoking is its most common cause. That’s why chronic bronchitis is typically referred to as “smoker’s cough.”

McConnell’s team decided to look for signs of bronchitis in vaping teens. After all, he explains, “There are a lot of these irritants in e-cigarette vapor.”

The researchers asked 2,000 students in the Los Angeles, Calif., area about their vaping habits. All were in their last two years of high school. The researchers also asked the teens about any respiratory symptoms. These could include coughs or phlegm.

Anyone who reported a daily cough for at least three straight months was judged to have chronic bronchitis. A student with persistent phlegm or congestion for three months or more…