Adrenomedullin and adrenotensin regulate collagen synthesis and proliferation in pulmonary arterial smooth muscle cells

To understand the pathophysiological mechanisms of pulmonary arterial smooth muscle cell (PASMC) proliferation and extracellular-matrix accumulation in the development of pulmonary hypertension and remodeling, this study determined the effects of different doses of adrenomedullin (ADM) and adrenotensin (ADT) on PASMC proliferation and collagen synthesis. The objective was to investigate whether extracellular signal-regulated kinase (ERK1/2) signaling was involved in ADM- and ADT-stimulated proliferation of PASMCs in 4-week-old male Wistar rats (body weight: 100-150 g, n=10). The proliferation of PASMCs was examined by 5-bromo-2-deoxyuridine incorporation. A cell growth curve was generated by the Cell Counting Kit-8 method. Expression of collagen I, collagen III, and phosphorylated ERK1/2 (p-ERK1/2) was evaluated by immunofluorescence. The effects of different concentrations of ADM and ADT on collagen I, collagen III, and p-ERK1/2 protein expression were determined by immunoblotting. We also investigated the effect of PD98059 inhibition on the expression of p-ERK1/2 protein by immunoblotting. ADM dose-dependently decreased cell proliferation, whereas ADT dose-dependently increased it; and ADM and ADT inhibited each other with respect to their effects on the proliferation of PASMCs. Consistent with these results, the expression of collagen I, collagen III, and p-ERK1/2 in rat PASMCs decreased after exposure to ADM but was upregulated after exposure to ADT. PD98059 significantly inhibited the downregulation by ADM and the upregulation by ADT of p-ERK1/2 expression. We conclude that ADM inhibited, and ADT stimulated, ERK1/2 signaling in rat PASMCs to regulate cell proliferation and collagen expression.

Is there an association between noise exposure and King Kopetzky Syndrome?

The condition in which individuals with normal pure tone audiograms complain of hearing difficulties, especially in the presence of background noise, (normal pure tone audiograms), has had a number of different names. The present term King-Kopetzky Syndrome was coined by Hinchcliffe in 1992. This is a common condition reported in 5 - 10% of those attending clinics complaining of hearing problems. A dominant genetic aetiology has been found in a proportion of cases. It may be associated with minor peripheral or central auditory dysfunction, and frequently the individuals exhibit anxious or depressive personalities. We found no relationship with noise exposure in a series of patients compared with matched controls. Here we review the evidence for and against such an influence and present fresh data in an attempt to define the role of noise, if any, in the causation of this condition. Our final conclusion is that there is no clear association between KKS and noise exposure