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DNA synthesis in human bone marrow is circadian stage dependent
R Smaaland1, O D Laerum, K Lote
1Gade Institute, Department of Pathology, Haukeland Hospital, University of Bergen, Norway.
Blood
|June 15, 1991
Summary
Human bone marrow (BM) cells show significant daily fluctuations in DNA synthesis, peaking during daytime hours. Understanding these circadian rhythms can optimize cancer treatments and stem cell harvesting.
Area of Science:
- Hematology
- Chronobiology
- Cell Biology
Background:
- Circadian rhythms influence physiological processes, including cell proliferation.
- Bone marrow (BM) cell DNA synthesis is crucial for hematopoiesis and response to therapies.
Purpose of the Study:
- To investigate the circadian variation in the fraction of human bone marrow cells undergoing DNA synthesis.
- To determine if timing of sample collection affects DNA synthesis measurements.
Main Methods:
- Collected bone marrow samples from healthy male volunteers every 4 hours over 24 hours.
- Analyzed DNA synthesis percentage using flow cytometry.
- Compared samples from sternum and iliac crest.
Main Results:
- Significant circadian variation in DNA synthesis was observed, with a 2-fold difference between lowest and highest values.
- Peak DNA synthesis occurred during waking hours (08:00-20:00), with lowest levels during early morning (00:00-04:00).
- Sternum samples showed higher DNA synthesis than iliac crest samples, but both exhibited similar circadian patterns.
Conclusions:
- Human bone marrow cell DNA synthesis exhibits a distinct circadian rhythm.
- Timing of bone marrow cell harvesting and administration of certain therapies could be optimized based on these circadian variations.
- This chronobiological understanding may enhance the efficacy of chemotherapy, growth factors, and stem cell transplantation.