Mesenchymal stem cell trials for pulmonary diseases

All adult tissues, including the lung, have some capacity to self-repair or regenerate through the replication and differentiation of stem cells resident within these organs. While lung resident stem cells are an obvious candidate cell therapy for lung diseases, limitations exist regarding our knowledge of the biology of these cells. In contrast, there is considerable interest in the therapeutic potential of exogenous cells, particularly mesenchymal stem/stromal cells (MSCs), for lung diseases. Bone marrow derived-MSCs are the most studied cell therapy for these diseases. Preclinical studies demonstrate promising results using MSCs for diverse lung disorders, including emphysema, bronchopulmonary dysplasia, fibrosis, and acute respiratory distress syndrome. This mini-review will summarize ongoing clinical trials using MSCs in lung diseases, critically examine the data supporting their use for this purpose, and discuss the next steps in the translational pathway for MSC therapy of lung diseases.

MEASUREMENT OF UPPER AND LOWER AIRWAY RESISTANCE AND CONDUCTANCE IN MAN

The resistances to flow in the upper (Ruaw) and lower (Rlaw) airway of human lungs were measured simultaneously with total airway resistance (Raw) and the volume of thoracic gas (Vtg) using the plethysmographic method and lateral pressure taps at the tracheal and oral levels. Ruaw is found to decrease slightly in a curvilinear fashion with increasing Vtg while its reciprocal, Guaw, is linearly related to Vtg with a negative Vtg intercept in normal subjects. Lower airway conductance (Glaw) is linearly related to Vtg with a slope of approximately 1.0 liters/sec per cm H2O per liter. From the partitioned resistances it is deduced that total airway conductance (Gaw) is curvilinear but approximately linear over the majority of the Vtg. A method of calculating resistance and conductance in the upper and lower airways from Raw versus Vtg data is presented using the equation Raw = Vtg/(A @#X002B; B Vtg) where B2/A @#X003D; dGlaw/ dVtg. Three hundred and sixty-two records of Raw versus Vtg data from 22 normal, asthmatic, and bronchitic subjects are then evaluated by this method and the results compared to those obtained by direct measurement.

intrathoracic or lower airway conductance; intrathoracic or lower airway resistance; extrathoracic or upper airway conductance; extrathoracic or upper airway resistance

Submitted on November 8, 1963