Changes in the mechanical and adhesive behaviour of human neutrophils on cooling in vitro

Abstract

Changes in the rheological properties of neutrophils may influence flow in microvessels that are cooled below normal body temperature. We investigated the effects of temperature on the mechanical and adhesive properties of human neutrophils by measuring transit times for individual cells flowing through 8-microm-pores in filters, and adhesion to P-selectin for cells perfused over a monolayer of activated platelets. Pore transit time increased as temperature was decreased from 37 degrees C to 0 degrees C. Upon rapid cooling, there was an instantaneous increase attributable to changes in aqueous viscosity. Interestingly, at 10 degrees C specifically, there was an additional increase in transit time, which was abolished by the inhibitor of actin polymerization, cytochalasin B. This meant that by 15 min, transit time at 10 degrees C was greater than at 0 degrees C. Most adherent cells on P-selectin were rolling, rather than stationary, at 10, 26 or 37 degrees C. The velocity of rolling slowed with decreasing temperature. The total number of adherent cells decreased with increasing wall shear rate, but for a given shear rate there was relatively little effect of temperature on attachment. However, when adhesion at 10, 26 or 37 degrees C was compared at equal shear stress (taking into account fluid viscosity), adhesion was greatest at 10 degrees C. Measurements of immunofluorescence showed that exposure to 10 degrees C gradually increased expression of beta2-integrin CD11b/CD18, but this did not cause transformation to stationary adhesion with time in the flow assay. Thus, neutrophils show an anomalous rheological response around 10 degrees C, which may impair local microcirculation in the cold. On rewarming, "activated" cells might inhibit recovery or become released into the systemic circulation.

Sustained hypothermia accelerates microvascular thrombus formation in mice

“…During cold temperatures, impaired rheological properties of the blood, namely, reduced viscosity (21) as well as enhanced stiffness and reduced deformability of cells (3,26), may compromise tissue perfusion. In addition, a reduction in temperature results in an increase in platelet and red blood cell numbers as well as a reduction in plasma volume (18,27), further impeding capillary passage and thus nutritive blood flow.…”

“…The fact that in regions without temperature extremes a seasonal variation in myocardial infarction is absent (20) emphasizes the ambient air temperature as an environmental risk factor. Seasonal changes in temperature further influence blood rheology with increase of viscosity of blood and resistance of red blood cells to deform as temperature is lowered, contributing in a major way to impaired circulation in the cold (21,26). The Caerphilly prospective heart disease study, comprising data on the association of air temperature and risk factors for ischemic heart disease from up to 2,036 men, indicates that the most important effect of a fall in temperature seems to be on the hemostatic system, with an increase of fibrinogen and a decrease in the fibrinolysis-inhibiting ␣ 2 -macroglobulin (8).…”

Mediators of Monocyte Migration in Response to Recovery Modalities following Resistance Exercise

“…To the best of our knowledge, no prior studies have examined the expression of CR3 in vivo or on monocytes following CWI. Nash and colleagues [18], however, have previously demonstrated a gradual increase in expression of CR3 when cultured neutrophils were cooled to 10°C in vitro . The contrasting results of this study may be due to a different response in monocytes when cooled.…”

“…CWI has also been demonstrated to decrease postexercise leukocytosis or increase the number of leukocytes, specifically, polymorphonuclear cells and lymphocytes, in response to muscle damage [15, 16]. CWI has been demonstrated to modulate cytokine and chemokine activity [4, 17], while cold exposure in vitro has shown to increase the expression of cell adhesion molecules, specifically the β 2-integrin CD11b/CD18, on cultured neutrophils [18], which may mediate phagocytic migration [5]. However, in vivo examination of the influence of CWI on the processes of monocyte cell adhesion is yet to be demonstrated.…”

Effect of hypothermia and HTK on the microcirculation in the rat cremaster muscle after ischaemia

“…This means that, in these experiments, leucocytes interacting with the endothelium during reperfusion had not been exposed to ischaemia and/or hypothermia (4 • C). Since HTK pretreatment did not alter the number of perfused capillaries nor the level of leucocyte-vessel wall interactions after cold ischaemia, we may conclude that alterations in leucocyte properties, such as the ones described by Nash et al [32] (transit time of leucocytes to flow through 8-µm pores in filters increased with decreasing temperature) and Forsyth and Levinsky [33] could not occur and hence, did not influence the cremaster microcirculation. In the case of 4 [15] or 6 h of warm ischaemia, however, HTK pretreatment did significantly reduce leucocyte rolling during the reperfusion period, whereas it did not influence capillary perfusion.…”