I recently came across a very interesting paper published in the journal Arthritis and Rheumatism (found online here) from a group in London who have a developed a mouse model of lung injury in scleroderma.  Basically, the scientists made a mouse with abnormal transforming growth factor B (TGFB), a protein which helps regulate inflammation and which is found to be abnormally elevated in skin and lung biopsies of scleroderma patients. These mice sometimes developed lung injury which looks, under the microscope, similar the the type of lung fibrosis seen in scleroderma patients.   The researchers found that by injecting the lungs of these abnormal mice with just saline, they were able to produce lung injury consistently. In normal mice, the saline caused no damage to the lungs and they had to inject a very caustic substance (bleomycin) to cause any lung damage.

Mice, of course, are not humans, and probably lung damage in scleroderma is more complicated that just the overproduction of TGFB.  It is still exciting, though, that a mouse model of lung injury in scleroderma now exists and may potential lead to new and better treatments in the future.  Doctors are not able to predict yet which patients will get lung involvement. It is also interesting to note that not all the experimental mice developed lung damage, suggesting that there may be some injury in scleroderma patients that causes them to develop lung damage. 

Reference: Hoyles RK et al, “Fibroblast-Specific Perturbation of Transforming Growth Facter B Signaling Provides Insight Into Potential Pathogenic Mechanisms of Scleroderma-Associated Lung Fibrosis: Exaggerated Response to Alveolar Injury in a Novel Mouse Model,” Arthritis & Rheumatism, 58 (4), April 2008, 1175-1188.