Size dependent platelet subpopulations: relationship of platelet volume to ultrastructure, enzymatic activity, and function

TLDR

A counterflow centrifugation method separated platelets into seven size‑based subpopulations, free of plasma proteins and other cells. The seven platelet subpopulations ranged in mean volume from 3.94 µm³ (Fraction 1) to 8.19 µm³ (Fraction 7), with progressively larger volumes, slightly higher densities, more dense bodies, and higher LDH activity in larger fractions compared to the smallest.

Abstract

A method for the separation of platelets on the basis of their size has been developed using counterflow centrifugation. Platelets were separated, free of plasma proteins and other cells, into seven subpopulations. The smallest‐sized platelets, designated as Fraction 1, had a mean platelet volume (MPV) of 3.94 ± 0.60 μm 3 (SD). Each successive fraction had a progressively larger MPV. The MPV for the largest‐sized platelets, designated Fraction 7, was 8.19 ± 0.64 μm 3 . The MPV for the original platelets prior to fractionation was 6.57 ± 0.61 μm 3 . The mean density of Fraction 1 platelets was 1.067 ± 0.002 g/cm 3 , while Fraction 7 had a mean density of 1.072 ± 0.001 g/cm 3 . Transmission electron microscopy demonstrated that Fraction 1 had 4.3 ± 0.9 dense bodies per platelet, and Fraction 7 had 12.6 ± 2.4 dense bodies per platelet. Platelet LDH activity showed that the Fraction 1 platelets had 4.77 ± 0.92 iu per 10 10 platelets; Fraction 7 platelets had 14.88 ± 1.23 iu per 10 10 platelets. The LDH activity in the platelets before separation into subpopulations was 9.47 ± 1.45 iu per 10 10 platelets.