In agreement with their slower alterations as compared to paranodes following dysmyelination. In contrast, other nodes displayed a decreased KCNQ2 and Nav labeling, which may correspond to newly formed nodes attesting to the ongoing remyelination. Since paranodin immunofluorescence is a robust marker of paranodes, differently altered in CIDP and CIAP, we tested whether it could be used as a help to the sometimes difficult diagnosis of these neuropathies. Using very simple criteria based on the intensity and distribution of paranodin immunoreactivity, we found that unaware observers were able to classify correctly biopsies as CIDP or CIAP in about 70% of the cases. It is important to note that these observers were not trained, and the inter-observer variability CYT387 suggests that the training of the observers may improve the accuracy. Future studies will examine whether they can be applied to less invasive biopsy procedures such as muscle or skin biopsies. In summary, our study characterizes for the first time the profound alterations of nodes of Ranvier in human chronic acquired neuropathies using both electron microscopy and immunofluorescence, and shows that alterations in paranodin immunofluorescence may provide an interesting contribution to the diagnosis. Endothelin-1 is a potent vasoconstrictor peptide secreted mainly by endothelial cells. It is also produced by other cells associated with cardiovascular homeostasis such as smooth muscle cells, cardiomyocytes, and macrophages. Activation of the ET-1 system is involved in the pathogenesis of several cardiovascular diseases, including hypertension, coronary artery disease, and chronic heart failure. It is presumed that the assessment of circulating ET-1 might represent a marker of disease progression and prognosis in patients with CHF. This issue is of a particular clinical importance, as the prognostic evaluation in this group of patients still remains a challenge. The precise identification of patients with CHF and the highest risk of death and/or disease progression would enable clinicians to intensify both pharmacotherapy and device-based management early in the course of the disease. In recent years, a huge emphasis has been put on neurohumoral mediators as potential prognostic markers in patients with CHF. Over the last several years, circulating natriuretic peptides have become widely accepted as diagnostic and prognostic measures in all stages of CHF, but also other complementary neurohumoral markers are intensively studied in this field. Increased circulating levels of ET-1 have been demonstrated in patients with CHF, but its prognostic significance has remained controversial so far. There is some evidence that high circulating ET-1 may be linked to poor outcomes in these patients.