Bronchial remodelling mainly involves an increased mass of bronchial smooth muscle (BSM), which is related with an increase proliferation of smooth muscle cells. Recently, using BSM cells obtained from severe asthmatics, we have demonstrated that such an increase proliferation was induced by an activation cascade (Trian, J Exp Med, 2007). It first started with a gallopamil-sensitive calcium influx which induced the activation of calcium-calmodulin kinase IV (CamK-IV). CamK-IV then enhanced mitochondrial biogenesis through the subsequent activation of various transcription factors including PGC-1α, NRF-1 and mt-TFA. BSM cell proliferation was mainly mitochondria-dependent in vitro in severe asthma whereas that of controls was virtually mitochondria-independent. However, in vivo effects of gallopamil remain to be investigated. We will thus enrol 32 severe asthmatic patients in a phase 2 randomized double blind study against placebo and evaluate the effect of gallopamil on BSM remodelling. Since inflammation also activates mitochondrial biogenesis in BSM cells, we will initially optimized asthma treatment for 3 months by both controlling co morbidities and decreasing bronchial inflammation using exhaled NO and eosinophil count within the induced sputum. We will then perform fiberoptic fibroscopy before and after 12 month treatment with gallopamil.
