'Stuffy Nose' Mouse: A Promise to Help Treat 31 Million with Sinusitis

Mice with inflamed nasal tissue being tested at a Johns Hopkins laboratory may be unable to tell if something smells bad or good, but their sensory deficit is nothing to turn up a nose at.

That is because, their developers say, the mice’s reversible loss of one of their key senses, which is essential to tasting food or sensing danger from foul odors, sets them apart from all other mice and binds them to an estimated 31 million Americans living with chronic sinusitis, a persistent inflammation of the tissue that lines the nasal and sinus cavities. Add to this group, millions of people with other disorders that affect smell, including viral infections, head traumas, tumors, Alzheimer’s and Parkinson’s diseases.

“A sense of smell in good working order is essential to our quality of life, and these genetically engineered mice give us the first real animal model for better understanding, treating and preventing people from suffering a loss of olfactory function due to sinonasal inflammation,” says sinusitis expert Andrew Lane, M.D., who led the team that developed the olfactory-compromised mice.

“And because we can turn on and off the inflammation in these mice, we really can mimic how the most overlooked and very disabling aspect of sinusitis, the loss of smell, or anosmia, plays out in people,” says Lane, an associate professor at the Johns Hopkins University School of Medicine.

Lane will cite smell and sinus tissue data from his studies with mice, and he will compare them to other clinical data, when he introduces the inflammation-induced, anosmic mice to fellow experts July 22 during a presentation at the XV International Symposium on Olfaction and Taste, in San Francisco, Calif.

“Until now, the lack of realistic animal models for each of the key symptoms of chronic inflammation in the nasal tissue - such as the growth of nasal polyps, the loss of the sense of smell, swollen sinus tissue, or clogged and runny noses - has slowed sinusitis research and hindered our search for therapies,” says Lane, director of the Johns Hopkins sinus center, where he treats hundreds of patients with the condition.

New therapies are needed, he says, as an alternative to long-term steroids, which block the inflammatory chemical pathway but also have debilitating side effects, including loss of bone density, cataracts in the eye and weight gain.

Another key advantage to the new sinusitis mouse, he points out, is that it can be more easily studied than human olfactory tissue, which is surgically difficult to cut out from deep inside the skull and because the tissue sits dangerously close to the brain.

Johns Hopkins scientists began their quest for a “stuffy nose” mouse with inflammation-produced anosmia in 2002.

Their first steps were performed in the lab, where researchers genetically modified developing mouse cells to breed a family that could secrete key cytokine proteins only in the olfactory, uppermost part of the nose. An overproduction of cytokines, which are better known for their role in the body’s immune response to disease-causing pathogens, are a telltale chemical signature in sinusitis.

Lane’s team focused its efforts on one of hundreds of cytokines, specifically, tumor necrosis factor alpha, or TNF?, because of its many links to sinusitis. TNF? is overactive during all kinds of inflammation, and the chemical is also known to accelerate olfactory nerve cell turnover. Unlike most other kinds of nervous tissue, the olfactory type can grow back, an evolutionary adaptation to the constant shedding of skin cells that line the nasal cavity.

Researchers first injected mouse egg cells with a gene for TNF? and a control system so that cells with the gene would secrete the cytokine on demand and only if activated.

In a second set of mice, Lane’s team planned to activate the control system only in olfactory tissue, by genetically implanting the controls to another gene, called CYP2G1, which is produced only in the mouse nose, specifically in its nourishing sustentacular cells that sit between nasal nerve cells.

Lane says the system had to be “nasally specific,” so that secretion of TNF? occurred in the mouse, much like it does in sinusitis in humans.

After breeding the two groups of mice to get their animal test model, of which there are 20 at any given time, scientists then turned on TNF? production by stimulating the sustentacular cells with tetracycline, an antibiotic trigger that was added to the mice’s drinking water. The system remained off when no tetracycline was added.

To make sure the model worked, mice were fed the drugged drinking water for nearly two months, and samples of olfactory tissue were tested weekly for any sense of smell in response to various odors.

Results showed that sense of smell, as gauged by minute electrical currents in olfactory tissue, dropped progressively, by half (50 percent) within two weeks, and stopping completely after six. When tissue was viewed under microscope, white blood cells were visible, a telltale sign of inflammation. Olfactory nerve cells had nearly disappeared.

But when researchers stopped the drug-induced sinusitis, olfactory nerve cells rebounded and grew back within a couple of weeks, “proving that what we have is a mouse with reversible olfactory loss due to inflammation, which should speed up our learning more about the disease and testing new therapies,” says Lane. “Ultimately, we hope to develop treatments that allow the sense of smell to recover, even in the presence of a hostile inflammatory environment due to sinusitis.”

His team’s next steps will be to test different cytokines, either alone or in combination, to clarify their roles in the loss of smell in sinonasal inflammation.

Future studies are also planned to monitor the effects of current steroid therapies on mouse olfactory tissue, in the hope of modifying or bolstering the treatments and speeding up delivery of these medications to inflamed tissue.

Another phase of research, he says, involves testing other anti-inflammatory drugs, such as infliximab (Remicade), which is used to treat arthritis, to see if they can spur growth of olfactory neurons during sinusitis.

Lane also plans to add more sinusitis features to the animal model, including progressive swelling of sinus tissue and rhinitis.

Funding for this study, conducted solely at Hopkins, was provided by the National Institute on Deafness and Other Communication Disorders, a member of the National Institutes of Health.

Besides Lane, other Hopkins researchers involved in this study were Justin Turner, M.D.; Lindsey May, B.S.; and Randall Reed, Ph.D.

JAMA Revisits Classic Hopkins Blue Baby Study That Revolutionized Cardiovascular Medicine

A Johns Hopkins study published 63 years ago will make an encore appearance in the July 16 issue of the Journal of the American Medical Association (JAMA) as part of a year-long retrospective celebrating JAMA's 125th anniversary by revisiting papers that changed the course of modern-day medicine. Full text of the original paper is available online.

The now-classic "blue baby" report by pediatric cardiologist Helen Taussig (1898-1986) and surgeon Alfred Blalock (1899-1964) first appeared in JAMA on May 19, 1945. In their paper, Taussig and Blalock described for the first time the physiology of tetralogy of Fallot, one of the most common congenital malformations of the heart that was poorly understood at the time, considered inoperable and ultimately fatal. The malformation causes inadequate blood flow from the heart to the lungs and profound lack of oxygen in the blood, giving an infant's skin its hallmark bluish hue, hence "blue baby."

In addition, the paper described the first three operations in medical history designed to alleviate the defect using a special "shunt" technique that increased blood flow from the heart to the lungs. Children undergoing the surgery experienced an immediate and dramatic improvement while still in the operating room. When their oxygen-starved bodies were finally flushed with oxygen-rich blood, their bluish complexions turned a healthy pink color, an observation that prompted Blalock to exclaim famously after surgery number three, "The boy's a lovely color now."

At the time, Taussig and Blalock almost certainly knew their work would dramatically change treatment of heart disease, and records at Johns Hopkins show that hundreds and hundreds of parents sought help for their children in the months that followed. The study also revolutionized pediatric cardiology, a then nascent field, and ushered in a new era of cardiac surgery. In hindsight, it also altered the course of academic medicine, according to Johns Hopkins Children's Center cardiac specialists writing in a July 16 JAMA commentary accompanying the reprint summary of the original paper.

Historians, filmmakers and journalists have widely told the story of the research and eventual surgical solution, which began with an idea from Taussig, who took it to Blalock, who first sketched a surgical approach to the repair. But it was Vivien Thomas (1910-1985), a black surgical technician, at the time working as a lab and office assistant with Blalock, who was instrumental in developing the necessary procedure and instrumentation in dogs.

This mélange of disciplines as disparate as pediatric cardiology, surgery and anesthesiology working toward treatment of a single disorder became and to date remains the model for progress and innovation in medicine.

"Not only did the team's unprecedented collaboration in effect give birth to pediatric cardiology and led to the first successful treatment of this fatal heart defect, but it later became the prototype of the bench-to-bedside approach, a staple in academic medicine today," says Anne Murphy, M.D., an author on the commentary and a pediatric cardiologist at Johns Hopkins Children's Center.

In the decades that followed, the teamwork by Taussig, Blalock and Thomas also foreshadowed Johns Hopkins' efforts to eliminate racial and gender inequalities in academic medicine. In the 1940s, at Johns Hopkins, the venerable citadel of medicine, Taussig, a woman, and Thomas, an African-American, teamed up with Blalock, a white male surgeon -- a diverse and brilliant crew whose combined talent and expertise pioneered a surgery that has saved millions of lives worldwide.

Taussig went on to achieve the status of a full professor at Johns Hopkins -- one of the first women to do so -- but Thomas' role was not fully acknowledged until much later, the JAMA commentators point out, and the original paper did not credit Thomas' contributions.

"The collaboration awakened everyone to the fact that talented people like Thomas, who would have clearly been a superb surgeon, were marginalized, and medicine suffered for it," says commentary co-author Duke Cameron, M.D., head of pediatric cardiac surgery at Johns Hopkins. "It was a realization that drove much of Hopkins' subsequent efforts toward equality and diversity."

In 1976, Hopkins gave Thomas an honorary doctoral degree and appointed him instructor in surgery. Today, one of the four advisory colleges for medical students at Hopkins is named for Thomas. Every entering class learns about Thomas' story and his contributions to modern medicine.

Four out of 1,000 U.S. babies are born with heart defects, such as tetralogy of Fallot. Worldwide, nearly 1 million babies are born with heart defects, researchers estimate.

“HICY” Drug Regimen Reverses MS Symptoms in Selected Patients

A short-term, very-high dose regimen of the immune-suppressing drug cyclophosphamide seems to slow progression of multiple sclerosis (MS) in most of a small group of patients studied and may even restore neurological function lost to the disease, Johns Hopkins researchers report. The findings in nine people, most of whom had failed all other treatments, suggest new ways to treat a disease that tends to progress relentlessly.

“We didn’t expect such a dramatic return of function,” says Douglas Kerr, M.D., Ph.D, associate professor of neurology at the Johns Hopkins University School of Medicine. “Although we’re very early in the game, we think this approach could be the linchpin of a significant advance for MS treatment.”

Researchers have used the so called HiCy treatments with some success at Johns Hopkins for a variety of other immune system disorders, including aplastic anemia, lupus and myasthenia gravis.

Cyclophosphamide kills immune-system cells but spares the bone marrow stem cells that make them. The usual method of delivering it in pulsed, small doses, however, can cause the drug to build up to toxic concentrations in patients’ bodies, causing a variety of side effects, including a greatly increased risk of infection.

Seeking an alternative way to use the drug, Kerr and his colleagues reasoned that HiCy might clear out the majority of a patient’s immune system in one fell swoop, then allow it to “reboot,” giving nerve cells a fresh start and an opportunity to repair themselves. In the current study, nine MS patients got a total single infusion of 200 milligrams per kilogram of cyclophosphamide intravenously over four days, a dose several times higher than that given in pulsed regimens but significantly lower than the total amount usually given patients over time.

Before treatment, Kerr says, the study participants were “the worst of the worst” among MS patients. Eight of the nine patients had failed conventional MS treatments, and several of them were wheelchair-bound.

Reporting in the June 9 Archives of Neurology, the Johns Hopkins team said the disease appeared to reverse course for seven of the nine patients over two years following treatments. Overall, the patients, men and women ranging in age from 20 to 47 at the beginning of the study, experienced a 40 percent reduction in scores of a standard test that measures disability. They also had an overall 87 percent improvement in scores on a composite test that measures physical and mental function.

MS, which affects approximately 400,000 people - predominantly women - in the United States, is believed to occur when the body’s immune system attacks the insulating sheath that coats nerve cells, causing it to degenerate. Consequently, electrical signals that the cells use to communicate with the rest of the body become progressively weaker, leading to symptoms that include numbness, tingling, cognitive problems and sometimes paralysis.

Researchers have identified four different subtypes of MS, and each is thought to be caused by a different autoimmune process. As a result, developing a treatment that effectively targets all types of MS has been challenging, says Kerr.

Kerr cautions that the “reboot” phenomenon didn’t work in all the patients. Two years after treatment, MRI images showed that the disease had reactivated in about half the study participants, suggesting that their renewed ability may not be permanent.

Kerr’s colleague Adam Kaplin, M.D., Ph.D., assistant professor of psychiatry and neurology at the Johns Hopkins School of Medicine, is leading efforts to improve HiCy therapy with a blood test in development that could predict which patients would benefit the most from HiCy treatment. Also, since immune cells that regrow after HiCy treatment may contain the same defect that leads to MS, Kaplin and his colleagues are working on a way to regrow only healthy immune cells.

Other Hopkins researchers who participated in this study include Chitra Krishnan, M.H.S., Robert A. Brodsky, M.D., Daniel B. Drachman, M.D., Richard J. Jones, M.D., Dzung L. Pham, Ph.D., Nancy D. Richert, M.D., Ph.D., Carlos A. Pardo, M.D., David M. Yousem, M.D., M.B.A., Edward Hammond, M.D., M.P.H., Megan Quigg, B.A., Carrilin Trecker, B.A., Justin C. McArthur, M.B.B.S., M.P.H., Avindra Nath, M.D., Benjamin M. Greenberg, M.D., M.H.S., and Peter A. Calabresi, M.D.