Immunolocalization of substance P and NK-1 receptor in vascular anomalies.

The peptide substance P (SP) shows a widespread distribution in both the central and peripheral nervous systems, but it is also ubiquitous in the human body. After binding to the neurokinin-1 (NK-1) receptor, SP regulates tumoral angiogenesis and proliferation. Thus, knowledge of this system is the key for a better understanding and, hence, a better management of many human diseases, including vascular anomalies (VA). This study aims to examine the expression and localization of both SP and the NK-1 receptor in different vascular anomalies using an immunohistochemical technique. Our results demonstrated predominantly nuclear localization of SP in venous malformations and in one haemangioma sample, in contrast with cytoplasmic expression in capillary malformations and rapidly involuting congenital hemangioma (RICH). NK-1 receptor showed a cytoplasmic localization in all VA. In summary, all these findings demonstrate that SP and NK-1 receptor are expressed in VA, with different expression patterns depending on the nature of the anomaly, suggesting that they could play an important role in the pathogenesis of VA.