According to the American Lung Association’s report Lung Disease Data: 2006, lung diseases cost the American economy $81.6 billion in direct healthcare expenditures every year, plus indirect expenses of $76.2 billion – a total of more than $157.8 billion.

Acute Lung Injury (ALI), also known as Acute Respiratory Distress Syndrome (ARDS), is caused by a traumatic injury to the lung, resulting in systemic inflammation and sepsis and the amount of oxygen in the arterial blood becoming abnormally low. ARDS is not a specific disease – instead, it is a type of severe, acute lung dysfunction that is associated with a variety of diseases, such as pneumonia, shock, sepsis (a severe infection in the body) and trauma. The injury to the lung can be direct or indirect, and is characterized by a leakage of protein-rich blood plasma and immune cells into the lung.  The resulting damage to the blood vessels and the lung tissue creates a dangerous open interface between the lung and the blood, facilitating the spread of microorganisms from the lung systemically, and starting a systemic inflammatory response. Moreover, the injury to epithelial cells impedes the lung’s ability to pump fluid out of airspaces, thus breathing ability, and may create abnormal development of excess fibrous tissue, further reducing the lungs capacity for oxygen.  Once this process begins, lung failure follows, and death.

According to the American Lung Association’s report Lung Disease Data: 2006, acute respiratory distress syndrome (ARDS) is the rapid onset of respiratory failure (inability to adequately oxygenate the blood) that can occur in critically ill persons of any age over one year.  The condition can be life-threatening and occurs when the lungs cannot perform normal gas exchange due to severe fluid buildup. The incidence of ARDS has been difficult to determine partly because of the variety of causes, clinical manifestations, and differing criteria used to define it. Various published estimates have ranged from 1.5 to 75 cases per 100,000 persons.  The National Heart, Lung, and Blood Institute (NHLBI) estimates that approximately 150,000 Americans are affected each year. Deaths usually result from multisystem organ failure due to the lack of oxygen, rather than lung failure alone.

To put it into perspective, ARDS can happen to anyone following a traumatic blow to the lungs, or even merely aspirating gastric content.  While not immediately obvious, the individual will suddenly experience complications in breathing resulting in death. Imagine the motorcycle rider who crashes his bike, causing him to sustain an acute lung injury.  Or perhaps the college student, having a wild night out with friends, goes on a drinking binge and passes out.  While the student is passed out, they aspirate gastric content, causing it flow the wrong way into the lungs.  Or the hospital patient in for a routine outpatient operation, who goes under general anesthesia, but experiences complications after surgery due to aspiration of fluids.  Even the surfer out to catch the biggest wave of the season, who gets slammed by the wave and inhales seawater.  All of these are common precursors to ARDS.

Dr. Klaus Ley is studying the immune response that happens as a result of the inflammation caused by the lung injury.  The first hours of the inflammation determine the progression and ultimate outcome of the disease.  Dr. Ley is working on the role of selectins in inhibiting the inflammatory response in the beginning stages, thus reducing the degree of disease infiltration. “You can get away with blocking the inflammation for a few hours, which may be enough to intervene and maintain oxygen flow,” said Ley.  Ley has found that in mice, they can block an immune response molecule called P-selectin, or thromboxane A2, a lipid partly responsible for clot formation.  “Preclinical studies point to practical therapies for the inflammation involved in ALI and ARDS” said Ley.

“This can hit young healthy people and they can die.  If we can control the inflammatory response, we may give those with Acute Lung Injury a chance to live,” said Ley.