Increased erythrocyte adhesion to VCAM-1 during pulsatile flow: Application of a microfluidic flow adhesion bioassay

Jennell White, Moira Lancelot, Sharada Sarnaik, Patrick Hines

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Sickle cell disease (SCD) is characterized by microvascular occlusion mediated by adhesive interactions of sickle erythrocytes (SSRBCs) to the endothelium. Most in vitro flow adhesion assays measure SSRBC adhesion during continuous flow, although in vivo SSRBC adhesive interactions occur during pulsatile flow. Using a well-plate microfluidic flow adhesion system, we demonstrate that isolated SSRBCs adhere to vascular cell adhesion molecule (VCAM-1) at greater levels during pulsatile versus continuous flow. A significant increase in adhesive interactions was observed between all pulse frequencies 1Hz to 2 Hz (60-120 beats/min) when compared to non-pulsatile flow. Adhesion of isolated SSRBCs and whole blood during pulsatile flow was unaffected by protein kinase A (PKA) inhibition, and exposure of SSRBCs to pulsatile flow did not affect the intrinsic adhesive properties of SSRBCs. The cell type responsible for increased adhesion of whole blood varied from patient to patient. We conclude that low flow periods of the pulse cycle allow more adhesive interactions between sickle erythrocytes and VCAM-1, and sickle erythrocyte adhesion in the context of whole blood may better reflect physiologic cellular interactions. The microfluidic flow adhesion bioassay used in this study may have applications for clinical assessment of sickle erythrocyte adhesion during pulsatile flow.

Original languageEnglish
Pages (from-to)201-213
Number of pages13
JournalClinical Hemorheology and Microcirculation
Issue number2
StatePublished - Jul 16 2015


  • Pulsatile flow
  • VCAM-1
  • VLA-4
  • adhesion
  • erythrocyte
  • microfluidics
  • sickle cell disease
  • variable shear


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