title: Alteration of Blood Flow in a Venular Network by Infusion of Dextran 500: Evaluation with a Laser Speckle Contrast Imaging System.
abstract: This study examined the effect of dextran-induced RBC aggregation on the venular flow in microvasculature. We utilized the laser speckle contrast imaging (LSCI) as a wide-field imaging technique to visualize the flow distribution in venules influenced by abnormally elevated levels of RBC aggregation at a network-scale level, which was unprecedented in previous studies. RBC aggregation in rats was induced by infusing Dextran 500. To elucidate the impact of RBC aggregation on microvascular perfusion, blood flow in the venular network of a rat cremaster muscle was analyzed with a stepwise reduction of the arterial pressure (100 → 30 mmHg). The LSCI analysis revealed a substantial decrease in the functional vascular density after the infusion of dextran. The relative decrease in flow velocity after dextran infusion was notably pronounced at low arterial pressures. Whole blood viscosity measurements implied that the reduction in venular flow with dextran infusion could be due to the elevation of medium viscosity in high shear conditions (> 45 s-1). In contrast, further augmentation to the flow reduction at low arterial pressures could be attributed to the formation of RBC aggregates (< 45 s-1). This study confirmed that RBC aggregation could play a dominant role in modulating microvascular perfusion, particularly in the venular networks.
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, Singapore.
authors.forename: Bumseok
authors.initials: B
authors.lastname: Namgung
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore.
authors.forename: Yan Cheng
authors.initials: YC
authors.lastname: Ng
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, Singapore.
authors.forename: Jeonghun
authors.initials: J
authors.lastname: Nam
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore.
authors.forename: Hwa Liang
authors.initials: HL
authors.lastname: Leo
authors.affiliation: Department of Biomedical Engineering, National University of Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore; Department of Surgery, National University of Singapore, Singapore.
authors.forename: Sangho
authors.initials: S
authors.lastname: Kim
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001809:Blood Viscosity / Q000187:drug effects; D003911:Dextrans / Q000494:pharmacology*; D003952:Diagnostic Imaging / Q000379:methods; D004903:Erythrocyte Aggregation / Q000187:drug effects*; D006400:Hematocrit; D007834:Lasers; D008297:Male; D008853:Microscopy / Q000379:methods; D051381:Rats; D012039:Regional Blood Flow / Q000187:drug effects*; D014699:Venules
chemical_list: D003911:Dextrans