Changes in the integrin-mediated adhesion of human neutrophils in the cold and after rewarming

Abstract

Changes in the mechanical and adhesive properties of neutrophils may modify perfusion of the microcirculation in cooled tissue. We tested how integrin-mediated adhesion of isolated human neutrophils was altered by cooling, or cooling and rewarming. First, adhesion was tested in a static assay. In the presence or absence of integrin-activating agents (formyl peptide, fMLP or Mn⁺⁺), there were significant reductions in adhesion to immobilised albumin at 10°C or 0°C compared to 37°C, although a slight increase in adhesion was induced by fMLP or Mn⁺⁺ at 10°C or 0°C. If cells were cooled for 5 or 20 min at 10°C and rewarmed (in the absence of activators) there was >100% increase in adhesion compared to cells held at 37°C. In a flow assay, neutrophils perfused over P-selectin at 37°C formed rolling attachments, but if neutrophils were cooled to 10°C and rewarmed for 1 or 5 min, there was transformation to stationary adhesion, which was reversed by antibody against CD18. After 20 minutes of rewarming, rolling was restored. Cooling and rewarming did not cause de novo expression of CD11b/CD18, and so appears to transiently activate constitutively-expressed integrin. Thus, integrin-mediated adhesion may be impaired in cold tissue but on return to normal temperature, neutrophils may transiently adhere locally or in remote vessels.