Mobilization of human CD34+CD133+ and CD34+CD133 stem cells in vivo by consumption of an extract from Aphanizomenon flos-aquae—related to modulation of CXCR4 expression by an L-selectin ligand?
Objective: The goal of this study was to evaluate effects on human stem cells in vitro and in vivo of
an extract from the edible cyanobacterium Aphanizomenon flos-aquae (AFA) enriched for a novel
ligand for human CD62L (L-selectin).
Experimental approach: Ligands for CD62L provide a mechanism for stem cell mobilization in
conjunction with down-regulation of the CXCR4 chemokine receptor for stromal derived factor 1.
Affinity immunoprecipitation was used to identify a novel ligand for CD62L from a water extract
from AFA. The effects of AFA water extract on CD62L binding and CXCR4 expression was tested
in vitro using human bone marrow CD34+ cells and the two progenitor cell lines, KG1a and K562. A
double-blind randomized crossover study involving 12 healthy subjects evaluated the effects of
consumption on stem cell mobilization in vivo.
Results: An AFA extract rich in the CD62L ligand reduced the fucoidan-mediated externalization of
the CXCR4 chemokine receptor on bone marrow CD34+ cells by 30% and the CD62L+ CD34+ cell
line KG1A by 50% but did not alter the CXCR4 expression levels on the CD34 cell line K562. A
transient, 18% increase in numbers of circulating CD34+ stem cells maximized 1 hour after
consumption ( Pb.0003). When 3 noncompliant volunteers were removed from analysis, the increase
in CD34+ cells was 25% ( Pb.0001).
Conclusion: AFAwater extract contains a novel ligand for CD62L. It modulates CXCR4 expression
on CD34+ bone marrow cells in vitro and triggers the mobilization of CD34+ CD133+ and CD34+
CD133 cells in vivo.
D 2007 Elsevier Inc. All rights reserved.
Keywords: L-selectin; Ligand; Human; Adult stem cell; CD34; CD133; KG1a; K562; Bone marrow; Mobilization; Bluegreen
algae; Cyanobacteria; Aphanizomenon; In vivo; In vitro
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