Circadian variation of granulocyte colony stimulating factor levels in man

Abstract

Glucocorticoids dose‐dependently increase plasma levels of granulocyte colony stimulating factor (G‐CSF). Based on the marked circadian rhythm of cortisol levels, we hypothesized that plasma levels of G‐CSF may also show a diurnal rhythm. A prospective study was conducted in 12 healthy young volunteers. Blood samples were obtained every 2 h over 24 h. G‐CSF levels averaged 18.0 ng/l (CI 13.1–22.9) at 8.00 am, increased continuously and reached peak values at 10.00 p.m. Individual harmonic regression analysis showed a clear circadian rhythm. The individual differences between nadir and peak levels averaged 54% (CI 43–65%). This pronounced diurnal rhythm of G‐CSF levels may help understand the circadian changes in circulating stem cells, bone marrow DNA synthesis, or bone marrow toxicity induced by some chemotherapeutic agents.

Hourly monitoring of circulating CD34+ cells to optimize timing of autologous apheresis in pediatric patients

“…Additionally, the circadian variation of G-CSF plasma level and CD34 þ is described. 32,23 As patients with POM II showed lower mean CD34 þ cell counts, a CD34 þ cell count at 0 and 4 h after G-CSF administration on the day before apheresis could give a hint of the need for adapted apheresis schedules.…”

“…While healthy adults with daily G-CSF-doses of 3-23 mg/kg show a maximum of CD34 þ cells at about 5 days after the start of administration, patients after polychemotherapy show a similar maximum at about day 10. 22 In healthy adults, a circadian rhythm of G-CSF in the PB and CD34 þ cell concentrations in the bone marrow has been established, with peak values found at 2200 hours 23 for G-CSF and between 1000 and 1500 hours 24 for CD34 þ cells, respectively. Therefore, a peak in peripheral CD34 þ counts after G-CSF administration is to be expected.…”

Hematopoiesis and its disorders: a systems biology approach

“…However, levels are not constant but actually oscillate about a constant level depending on a series of factors. 85 By experimentally characterizing these oscillations and explicitly including them, future models might provide a better fit to clinical data.…”

“…However, levels are not constant but actually oscillate about a constant level depending on a series of factors. 85 By experimentally characterizing these oscillations and explicitly including them, future models might provide a better fit to clinical data.Shochat also developed a model describing the effects of different G-CSF administration schedules on neutrophil dynamics. 86 Similar to Obeyesekere's, Shochat's model uses 6 easily obtainable parameters, making it clinically valuable.…”

Neutrophil homeostasis and its regulation by danger signaling

“…26,27 Adrenergic signals regulate rhythmic recruitment of leukocytes to tissues. 28 Moreover, intrinsic circadian rhythms in the migration of inflammatory Ly6C hi monocytes, 29 release of HSCs, 30 and inflammatory phenotype of MFs have previously been described.…”