latrunculin-a and Respiratory-Distress-Syndrome

The deformability of circulating leukocytes plays an important role in the physiopathology of several diseases like sepsis or acute respiratory distress syndrome (ARDS). We present here a microfluidic method for the passive testing, sorting and separating of non-adherent cell populations by deformability. It consists of microfluidic sieves in series with pore sizes decreasing from the upstream to the downstream. The method capabilities are demonstrated with monocytic cell lines (THP-1) treated by Jasplakinolide (a stabilizer of polymerized actin), LatrunculinA (an inhibitor of actin polymerization), and with the plasma of patients suffering from ARDS. Simple sample injection with standard syringes and pumps makes the method readily adapted for experimentation in hospitals.

Topics: Bridged Bicyclo Compounds, Heterocyclic; Cell Line; Cell Separation; Cells, Cultured; Depsipeptides; Filtration; Hemorheology; Humans; Leukocytes; Microfluidic Analytical Techniques; Porosity; Respiratory Distress Syndrome; Thiazolidines

Keratinocyte growth factor (KGF) is a potent mitogen that prevents lung epithelial injury in vivo. We hypothesized that KGF treatment reduces ventilator-induced lung injury by increasing the alveolar epithelial tolerance to mechanical strain. We evaluated the effects of in vivo KGF treatment to rats on the response of alveolar type II (ATII) cells to in vitro controlled, uniform deformation. KGF (5 mg/kg) or saline (no-treatment control) was instilled intratracheally in rats, and ATII cells were isolated 48 h later. After 24 h in culture, both cell groups were exposed to 1 h of continuous cyclic strain (25% change in surface area); undeformed wells were included as controls. Cytotoxicity was evaluated quantitatively with fluorescent immunocytochemistry. There was >1% cell death in undeformed KGF-treated and control groups. KGF pretreatment significantly reduced deformation-related cell mortality to only 2.2 +/- 1.3% (SD) from 49 +/- 5.5% in control wells (P < 0.001). Effects of extracellular matrix, actin cytoskeleton, and phenotype of KGF-treated and control cells were examined. The large reduction in deformation-induced cell death demonstrates that KGF protects ATII cells by increasing their strain tolerance and supports KGF treatment as a potential preventative measure for ventilator-induced lung injury.

Topics: Actins; Animals; Bridged Bicyclo Compounds, Heterocyclic; Cell Size; Cell Survival; Cells, Cultured; Epithelial Cells; Extracellular Matrix; Fibroblast Growth Factor 7; Fibroblast Growth Factors; Male; Microscopy, Fluorescence; Phenotype; Pulmonary Alveoli; Rats; Rats, Sprague-Dawley; Respiratory Distress Syndrome; Stress, Mechanical; Thiazoles; Thiazolidines; Ventilators, Mechanical