Separation of cells in density gradients with temporary solidification of the gradient: Application to Escherichia coli forms obtained by microwave treatment of pure cultures.

Gelatin added in certain concentration into the density gradient mixtures allows to solidify and melt the gradient reversibly. Such a method was applied to separation of partially disintegrated Escherichia coli VKM B-125 cells in discontinuous sucrose gradient which was optimized to obtain small round "nano-cells" free from other cell components. Gelatin added to the sucrose solutions had the advantages: i) accurate gradient layers were formed, ii) gelatin did not interfere with the cells and sub-particles during centrifugation, iii) solidified gelatin allowed to cut out the separated cell components, and iv) gelatin allowed to prepare ready-made solidified gradient centrifugation tubes into storage.

Pirfenidone and nintedanib modulate properties of fibroblasts and myofibroblasts in idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is an incurable lung disease with a poor prognosis. Fibroblasts and myofibroblasts are the key cells in the fibrotic process. Recently two drugs, pirfenidone and nintedanib, were approved for clinical use as they are able to slow down the disease progression. The mechanisms by which these two drugs act in in vitro cell systems are not known. The aim of this study was therefore to examine the effects of pirfenidone and nintedanib on fibroblasts and myofibroblasts structure and function established from patients with or without IPF. METHODS: Stromal cells were collected and cultured from control lung (n = 4) or IPF (n = 7). The cells were treated with pirfenidone and/or nintedanib and the effect of treatment was evaluated by measuring cell proliferation, alpha smooth muscle actin (α-SMA) and fibronectin expression by Western analysis and/or immunoelectron microscopy, ultrastructural properties by transmission electron microscopy and functional properties by collagen gel contraction and invasion assays. RESULTS: Both pirfenidone and nintedanib reduced in vitro proliferation of fibroblastic cells in a dose dependent manner. The number of cells from control lung was reduced to 47 % (p = 0.04) and of IPF cells to 42 % (p = 0.04) by 1 mM pirfenidone and correspondingly to 67 % (p = 0.04) and 68 % (p = 0.04), by 1 µM nintedanib. If both drugs were used together, a further reduced proliferation was observed. Both pirfenidone and nintedanib were able to reduce the amount of α-SMA and the myofibroblastic appearance although the level of reduction was cell line dependent. In functional assays, the effect of both drugs was also variable. CONCLUSIONS: We conclude that the ultrastructure and function of fibroblasts and myofibroblasts are affected by pirfenidone and nintedanib. Combination of the drugs reduced cell proliferation more than either of them individually. Human lung derived cell culture systems represent a potential platform for screening and testing drugs for fibrotic diseases.