Increased leptin mRNA expression in the blood of dogs naturally infected by Leishmania infantum.

Canine leishmaniosis (CL) is a severe and potentially fatal zoonosis caused by the protozoan Leishmania infantum. Severe forms of CL are commonly associated with a non-protective, humoral immune-response and high parasitic loads. Leptin, a 16 kD hormone mainly secreted by adipocytes, regulates both the innate and adaptive immunity. The goal of this study was to evaluate leptin mRNA expression levels in blood samples from privately owned dogs with CL (n = 11) and healthy controls (n = 10) using quantitative, real-time polymerase chain reaction. Blood samples from dogs with CL expressed significantly higher leptin mRNA levels (two-fold) compared to healthy controls (P = 0.018). The results suggest a possible involvement of leptin in the pathophysiology of Leishmania infection in dogs and the possible use of leptin as a biomarker for CL. Future studies investigating the immunological role of leptin in dogs with CL are warranted.