Somatostatin improved b cells mature in macaques during intestinal ischemia-reperfusion

Abstract

Aims Intestinal ischemia-reperfusion has been taken as an important pathophysiological process for multiple organ dysfunctions in critical patients. Recent studies reported that dual expression programs of the B cells receptors and Toll-like receptors on B-lymphocytes permit these ubiquitous cells to integrate both adaptive and innate immune functions. Our previous studies found that somatostatin inhibited the intestinal inflammatory injury after ischemiareperfusion in macaques. However, the changes of B cells and the effects of somatostatin on B cells after intestinal ischemia-reperfusion were unclear. Methods 15 macaques were divided into control, intestinal ischemia-reperfusion and somatostatin pretreatment groups. Immunohistochemistry was performed to identify the distributions of adaptive and innate immunity markers in the iliac mucosa. Hmy2.cir B lymphoblastoid cell line was cultured in vitro study. Enzyme-linked immunosorbent assay was used to measure IgM, IL-6 and SIgA, and the expressions of B cells transcription factors, PAX-5 and BLIMP- 1, were detected by Western blotting. Results B2 lymphocytes in normal Peyer's patches were presented the phenotype of PAX-5+CD20+ CD5-. Ischemia-reperfusion increased the numbers and sizes of Peyer's patches but with PAX-5+CD20-CD5- B cells, an unmatured set of B cells. Somatostatin partly kept the phenotype of mature B cells during ischemia-reperfusion. The innate immunity of B cells was inhibited whereas the adaptive immunity was increased in the intestinal mucosa in the somatostatin group, compared to the ischemia-reperfusion group. In vitro, somatostatin significantly inhibited IL-6 and promoted IgM by increasing the expression of both PAX-5 and BLIMP-1 in the proinflammatory condition. Conclusion Intestinal ischemia-reperfusion resulted in the proliferation of unmatured B cells which were involved in the augmentation of innate immunity. Somatostatin, with a bi-directional regulation function on innate as well as adaptive immunity of B cells, greatly improved B cells mature in macaques during ischemia-reperfusion. Preventive supplements of somatostatin may greatly limit intestinal injury and bacterial translocation during ischemia-reperfusion. Copyright: