Inhibitory effect of human umbilical cord mesenchymal stem cells (hUCMSCs) against Pseudomonas aeruginosa

Objective To investigate inhibitory effect of the human umbilical cord mesenchymal stem cells (hUCMSCs) on the growth of imipenem-resistant Pseudomonas aeruginosa (IRPA). Methods IRPA added into hUCMSCs were collected as the experimental group; while the IRPA co-cultured with fibroblast were taken as the control group. After 6 hours of co-cultivation, colony forming units (CFUs) of IRPA were counted in each group using plate counting method. Then the levels of Cathelicidin/LL-37 and human β-defensin 2 (HBD-2) in cultured medium were detected by Western-blot and ELISA. Results The CFUs of IRPA in experimental group were less than those in control groups, with significant differences (2.63 ± 0.58) × 106 CFU/ml vs. (3.69 ± 0.91) × 106 CFU/ml; t = 19.93, P < 0.05). Cathelicidin/LL-37 and hBD2 in experimental group were higher than those of experimental group [Cathelicidin/LL-37: (7.99 ± 0.45) ng/ml vs. (0.18 ± 0.04) ng/ml; t = 78.30, P = 0.007; HBD-2: (249.38 ± 14.19) pg/ml vs. (1.00 ± 0.58) pg/ml; t = 78.23, P = 0.009]. Conclusions hUCMSCs plays an inhibitory role on the growth of IRPA. The possible mechanism is that hUCMSCs could produce antimicrobial peptide: Cathelicidin/LL-37 and hBD2. Key words: Human umbilical cord mesenchymal stem cells; Imipenem-resistant Pseudomonas aeruginosa; Cathelicidin/LL-37; Human β-defensin 2