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Published on: August 9, 2019

Diurnal variation of circulating human myeloid progenitor cells

D D Ross1, A Pollak, S A Akman

  • 1Laboratory of Clinical Biochemistry, Baltimore Cancer Research Program, DCT, NCI, NIH, 655 West Baltimore Street, Baltimore, MD 21201, USA.

Experimental Hematology
|August 1, 1980
PubMed

Insights

Human circulating myeloid progenitor cells (CFU(c)) show significant diurnal variation, peaking at 9 a.m. This finding highlights the importance of standardizing blood collection times for accurate CFU(c) measurements.

Area of Science:

  • Hematology
  • Chronobiology
  • Cell Biology

Background:

  • Circulating myeloid progenitor cells (CFU(c)) are crucial for hematopoiesis.
  • Understanding diurnal variations in these cells is essential for accurate experimental design.

Purpose of the Study:

  • To investigate diurnal variations in human peripheral blood CFU(c).
  • To determine if specific myeloid progenitor subtypes exhibit circadian rhythms.

Main Methods:

  • Peripheral venous blood samples were collected every 3 hours from nine healthy males.
  • Mononuclear cells were isolated using Ficoll-Hypaque.
  • CFU(c) content was quantified via soft agar cloning assay using human placental conditioned medium (HPCM).

Main Results:

  • A statistically significant 24-hour cyclic variation in CFU(c) was observed, with a peak at 9 a.m. (P < 0.01).
  • This diurnal variation was primarily attributed to eosinophilic colonies (CFU(eos)).
  • Neutrophil/macrophage colonies (CFU(G,M)) showed a non-significant trend towards a 9 a.m. maximum.

Conclusions:

  • Human peripheral blood CFU(c) exhibit significant diurnal variation.
  • The time of blood collection must be standardized in experiments assessing peripheral blood CFU(c) to ensure reliable results.

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