Human Umbilical Cord Perivascular Cells and Human Bone Marrow Mesenchymal Stromal Cells Transplanted Intramuscularly Respond to a Distant Source of Inflammation.

Intravenously administered mesenchymal stromal cells (MSCs) are rapidly entrapped in the lungs, where they display an anti-inflammatory phenotype. Intramuscular (IM) delivery provides an increased MSC dwell-time, which could result in a sustained modulation of an inflammatory milieu. We studied the therapeutic effects of IM delivered MSCs to treat a distant (contralateral) inflammation, and compared the efficacy of neonatal (umbilical cord) and adult bone marrow MSCs (BMMSCs). Inflammation decreased over 48 h, but neonatal cells showed an earlier response than BMMSCs. Tumor necrosis factor-induced gene-6 (TSG-6) was released at the site of MSC delivery, while neutrophil infiltration was abrogated and inflammation reduced at the contralateral site. MSCs did not distribute to the organs or to the site of inflammation. Thus, IM delivery presents a promising alternative for the treatment of inflammation, and neonatal MSCs may represent a stronger candidate than those derived from adult BM to treat inflammatory diseases.