Needs for animal models of human diseases of the respiratory system.

Animal models are of two types those that occur spontaneously and those that the scientist produces by artefact. One value of spontaneously occurring models is that if pathogenetic mechanisms are identified, they give new leads for the study of human disease. There is a need for spontaneously occurring examples of so-called primary or idiopathic pulmonary fibrosis, pulmonary hypertension (arterial or venous), and emphysema. Acquired or artefactual models of each of these conditions are available and have led to better understanding of the pathological changes, but they have not led to identification of the basic or primary abnormality. A naturally occurring model of cystic fibrosis could be a major event in our control of this disease. A spontaneously occurring form of asthma is needed as a bridge between experiment and patient. Artefactual models that are needed are of bronchopulmonary dysplasia and shock lung. There is probably enough agreement--but only just--on the nature of bronchopulmonary dysplasia for specific needs to be identified. Here the questions concern the choice of an appropriate species--or several--in which to study the premature lung and its adaptation to air breathing and supportive therapy. Knowledge of comparative anatomy and physiology must influence choice of species for certain models. For adult respiratory failure, or shock lung, a model is needed that progresses to pulmonary hypertension. Spontaneous models of interstitial pneumonia and of infection, both viral and bacterial, are needed. An animal model of a disease is only as useful as the questions we ask of it.