Abstract
BACKGROUND AND AIMS: Epigenetic information delivered by intestinal exosomes can be useful for diagnosing intestinal diseases, such as ulcerative colitis, but the therapeutic effects of intestinal exosomes have not been fully exploited. We herein developed an autologous exosome therapy that could treat intestinal disease without any risk of inducing a systemic immunological reaction. METHODS: Intestinal exosomes were isolated and purified from faeces by our newly developed multi-step sucrose gradient ultracentrifugation method. Lipopolysaccharide [LPS]-activated macrophages were employed to test the in vitro anti-inflammatory ability of intestinal exosomes. To evaluate the in vivo anti-inflammatory activity of our system, we gavaged dextran sulphate sodium [DSS]-induced colitic mice with their own healing phase intestinal exosomes. RESULTS: Mouse intestinal exosomes are round extracellular vesicles with a hydrodynamic diameter of ~140 [±20] nm and a surface charge of ~-12 [±3] mV. Among the exosomes obtained at four different stages of DSS-induced ulcerative colitis [1, before treatment; 2, DSS-treated; 3, healing phase; and 4, back to normal], the healing phase exosomes showed the best in vitro anti-inflammatory effects and promotion of wound healing. Moreover, oral co-administration of autologous healing phase exosomes with DSS was found to significantly reduce the risk of a second round of DSS-induced ulcerative colitis in mice. CONCLUSIONS: Intestinal exosomes obtained during the healing phase that follows induced intestinal inflammation could strongly promote wound healing in the host. Oral administration of autologous exosomes from the healing phase could be a safe and effective approach for treating the ulcerative colitis of a given patient in the context of personalised medicine.