About 1 in 13 Americans suffer from asthma, a condition that has no cure. While the current medical care approach focuses on managing acute episodes and chronic symptoms, a new study in mice shows promise for long-term asthma treatment.
The study in mice from Aston University and Imperial College London, published in Respiratory Research, focused on a pericyte, a type of stem cell which is mainly found in the lining of blood vessels.
An allergic and inflammatory reaction in asthmatics causes the pericytes to move to the airway walls. Once there, the pericytes develop into muscle cells and other cells that make the airway thicker and less flexible.
According to the study, a protein known as CXCL12 triggers the movement of the pericytes. The researchers used a molecule called LIT-927 to block the signal from this protein by introducing it into the mice’s nasal passages.
Asthmatic mice that were treated with LIT-927 had a reduction in symptoms within one week, and their symptoms virtually disappeared within two weeks. The researchers also found that the airway walls in mice treated with LIT-927 were much thinner than those in untreated mice, closer to those of healthy controls.
“By targeting the changes in the airway directly, we hope this approach could eventually offer a more permanent and effective treatment than those already available, particularly for severe asthmatics who don’t respond to steroids,” lead researcher Dr. Jill Johnson from Aston University’s School of Biosciences said in a press release.
The causes of asthma vary
About 25 million people in the US and around 300 million globally have asthma. The condition has many causes, varying from environmental pollutants to obesity and emotional stress.
Dr. Drew Sutton, MD, a retired ENT doctor, says that asthma is most often caused by environmental allergens, for example, house dust mites, animal allergens, especially cat and dog, cockroach allergens, and fungi, as well as viral respiratory tract infections and exercise, hyperventilation.
- Shortness of breath
- Chest tightness or pain
- Wheezing when exhaling, which is a common sign of asthma in children
- Trouble sleeping caused by shortness of breath, coughing, or wheezing
- Coughing or wheezing attacks that are worsened by a respiratory virus, such as a cold or the flu
Sutton says that about 5-10% of patients have a predisposition to asthma called Samter's Triad or aspirin-exacerbated respiratory disease (AERD). It is a combination of asthma, aspirin sensitivity, and nasal polyps.
The Samter's Society, the AERD patients advocacy group, notes that aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) do not cause the disease; sensitivity to the medicines is a sign of the condition. The other symptoms are typical to asthma and nasal polyps.
The disease is difficult to treat, but the right combination of treatments can be effective. Avoiding NSAIDs will not prevent chronic symptoms, but ingestion of drugs may result in an acute reaction.
Providing the best quality of life
Dr. Johnson, the lead researcher of the study on pericytes movement, says that further research is needed before they can begin to test the potential treatment in people. It means that those who have asthma will have to wait for a breakthrough.
Sutton, MD, explains that asthma is difficult to treat because its pathophysiology is complex and involves airway inflammation, intermittent airflow obstruction, and bronchial hyperresponsiveness.
The medical care approach to asthma treatment currently includes treating acute asthmatic episodes and controlling chronic symptoms.
“The ultimate goals are to prevent symptoms, minimize morbidity from acute episodes, and prevent functional and psychological morbidity, so the best quality of life would be provided,” he says.
All asthma patients need quick-relief medicines that include acting beta2 agonists, such as short-acting bronchodilators, systemic corticosteroids, and ipratropium.
Meanwhile, pharmacologic management includes the use of control agents such as inhaled corticosteroids, long-acting bronchodilators (beta-agonists and anticholinergics), theophylline, and leukotriene modifiers, Sutton says.
“The more recent strategies in asthma treatment include the use of anti-immunoglobulin E (IgE) antibodies (omalizumab), anti–IL5 antibodies, and anti–IL4/IL13 antibodies in selected patients.”
1. CDC. Asthma.
2. Mayo Clinic. Asthma.
3. Respiratory Research. Chemokine CXCL12 drives pericyte accumulation and airway remodeling in allergic airway disease.
4. Aston University. Potential long-term treatment for asthma found - new research.
5. Asthma and Allergy Foundation of America. Asthma Medicines and Treatment.
6. The Samter's Society. Symptoms of AERD (Samter's Triad).