Human leucocyte rheology and tissue ischaemia

Reports suggest that white blood cells are involved in the development of tissue ischaemia. No studies on leucocyte rheology in the earliest stages of ischaemia exist. In 10 peripheral vascular disease (PVD) patients, 10 stable angina pectoris (SAP) patients and two groups of 10 matched controls leucocytes were separated by density and adherence into their granulocyte, lymphocyte and monocyte subpopulations. Blood samples were taken from the PVD group and respective controls before and after treadmill exercise (5 min 2 km-1 h-1, 12% slope) and from the SAP patients and controls before and after cycle ergometer test (25 W every 3 min). All the subpopulations were filtered through five micron diameter pore filters. Compared to controls, calf pain in the PVD patients was associated with an increase in monocyte filterability (P less than 0.01). ST depression in the SAP patients was linked to impaired granulocyte filterability (P less than 0.04). Therefore leucocyte rheology appears impaired in the earliest stages of ischaemia.

Age and blood cell rheology

The identification of the rheological variables responsible for alterations in capillary blood flow caused by the aging process could help explain why the incidence of vascular disease increases with age. Using new techniques for the separation and micropore filtration of the haemocellular subpopulations in 110 subjects aged 21-84 years, the aim of this study was to show to what extent, if any, age influences blood cell deformability. The filterability of mononuclear leucocytes decreased with age (r = 0.25; p less than 0.001), whereas the filterability of polymorphonuclear leucocytes or erythrocytes did not change significantly with age.