title: Circadian variations of bone marrow engraftability.
abstract: Circadian rhythms exist for hematopoiesis, but little is known about circadian variation of bone marrow engraftability and host "acceptability". Using a B6.SJL to C57BL/6J congenic transplant model, we chose 3-times with light on: Hours After Light Onset (HALO) 4, 8, and 12 and 3-times with light off: HALO 16, 20, and 24. The mice were conditioned on a 12-h light/dark cycles. Recipient mice (100 cGy) received 40 million cells. We demonstrated a significant variation of bone marrow engraftability into bone marrow, spleen, and thymus when donor animals were subjected to changes in their light/dark cycles. Two statistically significant nadirs in all three organs were observed at HALO 8 and 24 in experiments carried out in July, while an identical set of experiments in February analyzing engraftment in marrow and spleen showed nadirs at HALO 8, but not at HALO 24. Marrow progenitors from the July experiments showed nadirs at HALO 12 and 24. The percentage of progenitors in S phase peaked at HALO 8 and 24. Interestingly, there were no changes in the ability of host to accept grafts with changes in the light/dark cycles of host animals. Circadian variations of bone marrow engraftability are important and should be considered in bone marrow transplant strategies.
authors.affiliation: Centre Hospitalier Notre-Dame et Reine Fabiola, Charleroi, Belgium.
authors.forename: Lionel
authors.initials: L
authors.lastname: D'Hondt
authors.forename: Christina
authors.initials: C
authors.lastname: McAuliffe
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Damon
authors.forename: Judith
authors.initials: J
authors.lastname: Reilly
authors.forename: Jane
authors.initials: J
authors.lastname: Carlson
authors.forename: Mark
authors.initials: M
authors.lastname: Dooner
authors.forename: Gerald
authors.initials: G
authors.lastname: Colvin
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Lambert
authors.forename: Chung-Cheng
authors.initials: CC
authors.lastname: Hsieh
authors.forename: Houri
authors.initials: H
authors.lastname: Habibian
authors.forename: Kimberly
authors.initials: K
authors.lastname: Stencel
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Quesenberry
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D016026:Bone Marrow Transplantation / Q000379:methods*; D002452:Cell Count; D019070:Cell Lineage; D002478:Cells, Cultured; D002940:Circadian Rhythm; D003114:Colony-Forming Units Assay; D005269:Femur / Q000166:cytology; D014644:Genetic Variation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D012621:Seasons; D013154:Spleen / Q000166:cytology; D013936:Thymidine / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology; D013977:Tibia / Q000166:cytology; D013997:Time Factors; D014183:Transplantation, Heterologous; D014316:Tritium
chemical_list: D014316:Tritium; D013936:Thymidine