Researchers track down protein responsible for chronic rhinosinusitis with polyps

Nov 23, 2009

A protein known to stimulate blood vessel growth has now been found to be responsible for the cell overgrowth in the development of polyps that characterize one of the most severe forms of sinusitis, a study by Johns Hopkins researchers suggests. The finding gives scientists a new target for developing novel therapies to treat this form of the disease, which typically resists all current treatments.

Chronic sinusitis, a constant irritation and swelling of the nasal passages, is a common condition thought to affect about one out of every six people. This problem has several forms with a range of severities. One of the most severe forms produces , overgrowths of unhealthy sinus tissue that can block the nose and sinus passages and make breathing through the nose difficult or impossible. This often results in pain, swelling, and an increase in infections. Though researchers aren't sure how many people have this subtype, it's estimated to affect between 15 and 30 percent of sinusitis patients.

"This type of sinusitis isn't subtle—you can spot the patients with polyps from across the room. They're breathing through their mouths, they talk with nasal voices, they're constantly sniffling, and their faces are swollen," says Jean Kim, M.D., Ph.D., assistant professor in the Departments of Otolaryngology and Allergy and Clinical Immunology at the Johns Hopkins University School of Medicine, and a researcher at the Johns Hopkins Allergy and Asthma Center at the Johns Hopkins Bayview Medical Center.

Kim explains that surgery to remove the polyps is one of the most common treatments for this disease. However, nasal and sinus polyps in these patients almost always regrow. "Once the patient has entered the cycle of growing polyps, it's very hard to get out," she says. Another common treatment is oral steroids, but these drugs are fraught with many harmful side effects and also only temporarily treat the disease.

She and her Johns Hopkins colleagues have long studied sinusitis, often growing sinus cells isolated from patients in petri dishes. After noticing that cells from patients with polyps typically multiplied faster than cells from normal patients, the researchers speculated that cells from polyp patients might be producing extra amounts of some type of growth factor, a protein that encourages cell growth.

To identify which growth factor might be to blame, the researchers had sinusitis patients with and without polyps rinse their sinus passages with a wash solution, then tested the runoff for the presence of various growth factors. They found that solution from patients with polyps contained high amounts of a substance called vascular endothelial growth factor, or VEGF, a protein important for normal blood vessel growth that also seems to play a key role in a variety of diseases, including cancer. The more VEGF they found in a cell culture, the faster those cells grew.

To further examine whether this protein is present not only in the sinus passages but also in the sinus tissue, Kim and her colleagues used a stain that highlights VEGF on sinus tissue removed from polyp-producing patients and those with other types of sinusitis. The stained tissue from polyp patients "lit up very dramatically, like a city skyline," Kim says, while the tissue from other patients showed little to no staining.

Though these results confirmed that the sinuses of patients with polyps were overproducing VEGF, the researchers still weren't sure that VEGF was instigating cell overgrowth seen in polyps. Looking for a cause-and-effect relationship, Kim and her team treated cells isolated from sinusitis patients with agents that inhibit VEGF production and action. The cells from polyp-producing patients slowed their growth rate to match that of normal patients.

"It's a strong indicator that VEGF is indeed responsible for the over-exuberant cell growth that contributes to polyp development," Kim says.

Her findings, published in the Dec. 1 American Journal of Respiratory and Critical Care Medicine, suggest that doctors may eventually treat sinusitis in patients with polyps using therapies that reduce VEGF in sinus tissues. "In the future, we might have a nasal spray with an anti-VEGF agent in it," she proposes.

The results also suggest a new way of predicting which patients will go on to develop polyps. They might also simplify tracking the progression of the disease, a process which now relies on repeated CT-scans, which expose patients to radiation. Since many patients with polyps already use sinus washes to ease their symptoms, doctors may be able to use any VEGF present in the runoff from these washes as a marker for the disease and its severity.

Source: Johns Hopkins Medical Institutions

Explore further: Restrictions lifted at British bird flu farm

add to favorites email to friend print save as pdf

Related Stories

New procedure claims to treat sinusitis

May 04, 2006

A non-surgical procedure offered by a California firm is seen by some doctors as a breakthrough for treating sinusitis but other experts are not so sure.

Recommended for you

Restrictions lifted at British bird flu farm

12 hours ago

Britain on Sunday lifted all restrictions at a duck farm in northern England after last month's outbreak of H5N8 bird flu, the same strain seen in recent cases across Europe.

Recorded Ebola deaths top 7,000

Dec 20, 2014

The worst Ebola outbreak on record has now killed more than 7,000 people, with many of the latest deaths reported in Sierra Leone, the World Health Organization said as United Nations Secretary-General Ban ...

Liberia holds Senate vote amid Ebola fears (Update)

Dec 20, 2014

Health workers manned polling stations across Liberia on Saturday as voters cast their ballots in a twice-delayed Senate election that has been criticized for its potential to spread the deadly Ebola disease.

Evidence-based recs issued for systemic care in psoriasis

Dec 19, 2014

(HealthDay)—For appropriately selected patients with psoriasis, combining biologics with other systemic treatments, including phototherapy, oral medications, or other biologic, may result in greater efficacy ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.