Marti´n-Gonza´lez J , Sa´nchez-Jime´nez F , Pe´rez-Pe´rezA , Carmona-Ferna´ndez A , Sa´nchez-Margalet V , Segura-Egea JJ. Leptin expression in healthy and inflamed humandental pulp. International Endodontic Journal. Aim To investigate the expression of leptin inhealthy and inflamed human dental pulp.Methodology Twenty-one pulp samples wereobtained from freshly caries- and restoration-freeextracted human third molars. In seven-third molars(inflamed pulp group), inflammation was inducedprior to extraction. Pulp samples were processed, andleptin expression was determined by quantitative real-time PCR (qRT-PCR) and the amount of leptin byimmunoblot.Results All healthy and inflamed dental pulpsamples expressed leptin. Western blot analysisrevealed the presence of a protein with an apparentmolecular weight of ~16 kDa in human dental pulp,which corresponds to the estimated molecular weightof leptin. The expression of leptin mRNA in dentalpulp was confirmed by qRT-PCR analysis, and the sizeof the amplified fragments (296 bp for leptin and194 bp for cyclophilin) was confirmed by agarose gelelectrophoresis. The expression of leptin in theinflamed pulp group was significantly greater(P < 0.05) than in healthy teeth. The relative amountof leptin in inflamed pulps was almost twice than inhealthy pulps.Conclusions For the first time, the presence ofleptin in human dental pulp tissues has been demon-strated. The upregulation of leptin expression ininflamed pulp samples suggests that leptin can play arole in pulpal inflammatory and immune responses.Keywords: dental pulp stem cells, leptin, pulpalimmune response, pulpal inflammatory response,pulpitis.