Intravenous Transplantation of Autologous Adipose Tissue-Derived Mesenchymal Stem Cells and a Change in Chronic Pain

Globally, more than 300 million individuals experience chronic pain. Chronic inflammation with increased infiltration of activated inflammatory cells is a major cause of chronic pain. Mesenchymal stem cells (MSCs) are known to suppress excessive inflammation, and their mechanism of action has been shown to be a gap junction-mediated interaction with the endothelium and circulating white blood cells. In vitro-expanded autologous adipose tissue-derived MSC were transplanted intravenously into patients with chronic pain. The degree of pain was evaluated before and after treatment using the Faces Pain Scale and Pain Disability Assessment Scale. This study included 28 patients. The potential of MSCs for gap junction-mediated transfer of small water-soluble molecules was evaluated in vitro. Autologous adipose tissue-derived MSC significantly attenuated chronic pain compared with pain before cell transplantation. In vitro analysis confirmed that about 80% of transplanted MSC could transfer small molecules via gap junctions. Our results indicate that transplantation of in vitro-expanded adipose tissue-derived MSC, which can transfer small molecules via gap junctions, is safe and may suppress chronic pain. Further double-blinded clinical studies are required to confirm the effect.