Substance P in Long-Lasting Asthma. Immunoinflammatory pathways

Background: Substance P (SP) was described at the beginning of the 20th Century, and its biological action was recognized to have implications in neurogenic inflammation and constriction of smooth muscles. The changes associated with inflammatory chronicity can compromise organ function reversibility. The role of neuromechanisms in the pathology of the disease has been investigated in order to achieve better diagnosis and therapeutic approaches. The stimulation of human cells, such as macrophages and polymorphonuclear cells by SP leads to their activation and to the release of reactive oxygen species (ROS) by these cells. Consequently, a continuous inflammatory disability is observed, mainly if a decrease in antioxidant defence occurs. SP is a substrate for dipeptidyl peptidase IV (DPPIV), which is a multifunctional molecule with enzymatic and proinflammatory activities. CD26 is considered an activation T cell marker. The aim of the present study was to analyse if serum SP values in longlasting asthma patients were related to lung function parameters. It was also decided to analyze the relationship of SP with superoxide dismutase (SOD) and total antioxidant activity in serum (TAS), as well as its association to CD26/DPPIV values considering their immunological and inflammatory prop