Clinically feasible method for assessing leukocyte rheology in whole blood

Riha Shimizu,Yasuto Horie,Nobuhiro Hata,Atsuhiko Kawabe,Takanori Yasu,Seiko Yamakoshi,Hirokazu Yanaka,Yuki Nakatani,Takaaki Nakamoto,Hirotsugu Fukuda,Yuji Kikuchi,Yasushi Matsushita,Masashi Yamazaki,Hiroyuki Sugimura,Yuma Tamura

doi:10.1007/s00380-019-01486-y

Abstract

This study reports a novel method for assessment of leukocyte rheological activation with a new designed microchannel array chip to mimic the human microvascular network for microchannel array flow analysis (MCFAN). Study subjects were 79 healthy volunteers and 42 patients with type 2 diabetes mellitus (DM) and 36 patients with acute coronary syndrome (ACS). Using the anticoagulants heparin and ethylene-diamine-tetraacetic acid (EDTA)-2Na which inhibits platelets and leukocytes by chelating Ca2+, we were able to quantify leukocyte rheological activation by the subtraction of passage time of blood treated with both heparin and EDTA-2Na from that of blood treated with heparin only. We confirmed that passage times of whole blood with heparin + EDTA-2Na were always shorter than those of whole blood with only heparin in healthy subjects and patients with DM or ACS under suction pressures of − 30 cmH2O. There was a significant correlation between delta whole blood passage time {(heparin tube) − (EDTA-2Na + heparin)} and serum levels of myeloperoxidase and adhesive leukocyte number, respectively, even in blood from patients with DM or ACS, who suffered from inflammation. In conclusion we have developed a clinically feasible method for assessing leukocyte rheological activation in whole blood in ex vivo.

Highlights

Abnormal activation states of leukocytes and leukocyte–platelet interactions play key roles in organ injury induced by atherosclerotic disease [1, 2], diabetes mellitus, and other inflammatory conditions [3–5]
We developed a clinically feasible method for assessing leukocyte rheology in whole blood using a microchannel flow analyser (MCFAN) with a novel silicon chip designed to mimic the human microvascular network
The present new microchannel array chip prevents artefactual activation of platelets by a stepwise decrease in microchannel diameter (Video 1). This artefactual activation of platelets downstream of capillaries induced by conventional microarray chips with abrupt narrowing may prolong to the whole blood passage time somewhat [17]

Summary

Introduction

Abnormal activation states of leukocytes and leukocyte–platelet interactions play key roles in organ injury induced by atherosclerotic disease [1, 2], diabetes mellitus, and other inflammatory conditions [3–5]. A microchannel flow analyser (MCFAN) with a conventional siliconized chip (BK 7-7-4.5D) is a generally accepted ex vivo capillary model for the evaluation of whole blood rheology [5–7, 14–16]. In conventional microarray chips with abrupt narrowing, we have observed platelet aggregation and platelet–leukocyte adhesion at the post-capillary venules and plugging of some terminal capillaries, possibly due to activation of glycoprotein IIb/IIIa on platelets caused by the abrupt increase in shear stress [17]. This artefactual activation of platelets downstream of capillaries may prolong the whole blood passage time somewhat

Methods

Results

Conclusion