BACKGROUND: Biologics containing growth factors are frequently used to enhance 
healing after musculoskeletal injuries. One mechanism of action is thought to be 
though the ability of biologics to induce homing and migration of endogenous 
mesenchymal stromal cells (MSCs) to a target tissue. However, the ability of 
biologics to stimulate chemotaxis (directed migration of cells) and chemokinesis 
(increase rate of cell migration) of MSCs is unknown.
HYPOTHESIS/PURPOSE: The aim of this study was to directly compare the ability of 
biologics including platelet rich plasma (PRP) and bone marrow concentrate (BMC) 
to induce MSC migration. The hypothesis was that leukocyte-low platelet rich 
plasma (Llo PRP) would induce migration to a greater extent than leukocyte-high 
platelet rich plasma (Lhi PRP) or BMC.
METHODS: Bone marrow-derived MSCs were isolated from 8 horses. Migration of MSCs 
toward a biologic (BMC, Llo PRP, and Lhi PRP) or the positive control platelet 
derived growth factor (PDGF) was continuously traced and measured for 24hrs 
using time-lapse microscopy and a microfluidics device. Cell migration, 
chemotaxis and chemokinesis were determined by measurements of displacement, 
number of cells migrated, and cell flux.
RESULTS: All biologics resulted in a significantly greater percentage of MSCs 
migrated compared to the positive control (PDGF). MSCs migrated further toward 
BMC compared to Llo PRP. Cell migration, measured as cell flux, was greater 
toward BMC and Lhi PRP than Llo PRP.
CONCLUSION: The biologics BMC and Lhi PRP elicit greater chemotaxis and 
chemokinesis of MSCs than Llo PRP. However, all biologics recruited the same 
number of MSCs suggesting that differences in other regenerative effects, such 
as growth factor concentration, between biologics should be strongly considered 
when choosing a biologic for treatment of musculoskeletal injuries. The results 
of this study have the potential to reduce the need, risks, and costs associated 
with MSC culture and delivery.