Analysis of Ambient Influences Affecting Interleukin-6 Secretion in the Context of Clinical Trials of Stem Cell Therapy for Myocardial Infarction.

ABSTRACT

BACKGROUND: Contradictory results of large clinical trials of stem cell therapy in acute myocardial infarction (AMI) have impeded a wider clinical use. As signalling via paracrine factors in AMI has received more and more attention recently, we sought to compare processing protocols with special emphasis on interleukin-6 (IL-6), a factor of major relevance for triggering cardioprotective signals via STAT3 and PI3K. METHODS: Bone marrow and peripheral blood mononuclear cells were processed according to protocols used in the REPAIR-AMI and ASTAMI study. RESULTS: Keeping cells at higher temperatures significantly boosted secretion of IL-6. Moreover, the use of autologous serum and X-Vivo medium was superior over reagents used in the protocol of the ASTAMI study. CONCLUSIONS: External influencing factors (higher temperature, use of a modern cell culture medium supplemented with serum) led to higher concentrations of IL-6. These results could provide an explanation for the superior results found in the REPAIR-AMI study.