THE ENEMY WITHIN

UNCONTROLLED INFLAMMATION UNDERLIES MANY CONDITIONS COMMON IN PEOPLE WITH ARTHRITIS. LEARN HOW TO TAMP IT DOWN.

EMILY DELZELL

Inflammation is part of a healthy immune response to protect and heal the body. But in recent years, scientists working in a host of different specialties have pinpointed it as a root cause of multiple diseases.

The signs of inflammation – redness, swelling, heat and pain among them – are all too familiar when you have arthritis. In inflammatory types of arthritis, such as rheumatoid arthritis (RA), psoriatic arthritis (PsA) and ankylosing spondylitis (AS), and in related conditions such as gout and lupus, ongoing, chronic inflammation underlies most of the symptoms and damage.

Even in osteoarthritis (OA), traditionally considered the result of wear and tear, evidence suggests low-grade inflammation spurs joint damage, pain and other symptoms. As OA progresses, ongoing tissue damage and the cellular stress it causes likely feed inflammation in joints, says Carla R. Scanzello, MD, Ph.D., assistant professor of medicine at the University of Pennsylvania in Philadelphia. “This sustained inflammation may further promote progression of disease, creating a vicious cycle,” she says. (See “Surprising OA Trigger,” page 33.)

The Two Sides of Inflammation

Short-term, acute inflammation is the body’s main protection against infection or injury. When either of these happen, the immune system surges inflammatory defenders into the bloodstream, which carries specialized cells and proteins to parts of the body that need them, killing invading bacteria or viruses, clearing away debris and delivering nutrients that repair injured tissue.

“Our immune system helps us fight off infections of all different types and is also important in defending us from cancer and in the wound-healing process,” says rheumatologist Timothy Niewold, MD, a professor and the director of the Colton Center for Autoimmunity at the NYU Grossman School of Medicine in New York City.

However, he adds, “In autoimmune and inflammatory conditions, the immune system is overactive, causing inflammation in the absence of an infection or other external cause.” In diseases like RA, the immune system identifies normal tissues as invaders and responds with an inflammatory defense that doesn’t stand down, explains Dr. Niewold. Inflammatory cytokines can then spread throughout the body, attacking healthy tissues and causing destructive changes and disease.

In inflammatory arthritis, damage often begins in joints but can move to the lining of the arteries, causing cardiovascular disease (CVD), or into eye structures, provoking diseases such as uveitis. That’s why people with RA, PsA and other rheumatic conditions often develop these and other comorbidities (two or more diseases that exist together).

Other causes of chronic, body-wide inflammation include highly processed, sugary, high-fat foods; tobacco smoking; being overweight; stress and anxiety; and simply getting older, which can make the immune system less efficient. Plus, air pollution, allergens and other daily encounters can trigger the immune system and its inflammatory army.

“Chronic inflammation can be thought of as a type of stress response that causes many adverse effects in the body,” Dr. Niewold says.

A Common Link

Chronic inflammation directly contributes to the development of CVD, diabetes, metabolic syndrome (a cluster of risk factors including abdominal obesity, high blood pressure and elevated cholesterol) and numerous other diseases, says Samia Mora, MD, associate professor of medicine at Harvard Medical School and a cardiologist at Brigham and Women’s Hospital in Boston.

WHAT’S THE GUT GOT TO DO WITH IT?

The trillions of microorganisms that live in the digestive tract are collectively known as the gut microbiome. These “microbiota” help stabilize the immune system and are involved in many other health and disease impacts in the body.

If the balance of harmful versus helpful microbiota tips in the unhealthy direction, it can provoke chronic, low-grade inflammation and potentially cause disease, says Thomas W. Buford, PhD, associate professor and endowed scholar in the Department of Medicine at the University of Alabama at Birmingham. Studies of people with early rheumatoid arthritis, for example, show their microbiota composition is often less healthy than in those without RA.

“One explanation for what might be happening is the ‘leaky gut’ hypothesis, in which the gut becomes more permeable, and fragments of these microbiota escape into the bloodstream,” Buford says. “There, the immune system recognizes them as foreign and responds with inflammation that can invade joint tissues.”

Foster gut health by eating a fiber-rich diet, which provides prebiotics (food) for “good” bacteria. Also, manage stress and get regular exercise and sleep. Buford suggests asking your doctor about taking probiotic supplements to boost levels of healthy microorganisms.

“In people with inflammatory arthritis, the risk from inflammation is as strong as that of other known risk factors, such as high cholesterol or high blood pressure, for diseases such as cardiovascular disease or diabetes,” she says.