GPS® HI vs. Cascade® System Output Characterization
Jennifer Woodell-May, Ph.D.
Biomet Biologies, Warsaw, IN
Introduction:
Growth factors eluted from the clots over time (Fig. 2). The
Platelet-rich plasma (PRP) is cleared to be mixed with overall growth factors released from the GPS® Dl device were
autograft or allograft for orthopedic applications. The GPS® III greater than the amount available from the Cascade® device. A
System is a. platelet separator that produces 6 ml of platelet-rich higher concentration of growth factors was found in the discarded
plasma (PRP) from 60 ml of whole anticoagulated blood. The liquid of the Cascade® device than was detected in the Cascade®
Cascade® Autologous Platelet System is a competitive device that system elution study (Table 2). The clot from each Cascade®
produces a platelet blood clot generated from 9 ml of whole device varied in size by donor (Fig 2.).
anticoagulated blood. The Cascade® device is marketed on cost
PDGF-AB release
effectiveness and ease of use. A comparison study was performed
on the GPS® HI and the Cascade® systems to assess the ability of
each device to concentrate the platelets and deliver growth
factors.
Methods:
For the GPS® ffl device, fresh human blood (n=4) was
drawn into a 60 ml syringe (52 ml blood and 8 ml of ACD-A). A
baseline complete blood count (CBC) was gathered using the
blood collected for the GPS® IE device. The GPS® III device was
centrifuged at 3200 rpm for 15 minutes. The PRP was extracted
and placed on a rocker for 15 minutes. A CBC was gathered on
the PRP. The PRP was clotted with thrombin (1000 U/ml in
CaCl2). Thirty-five ml of phosphate-buffered saline was added to
the clot
Figure 2: Average growth factor elution from clots: a.)PDGF-AB b.)TGF-|31
For the Cascade® device (n=5), 9 ml of blood were drawn c.)VEGFandi)TSP-l.
directly into a vacutainer tube preloaded with ACD-A Table 2. Growth factors in the discarded liquid form the Cascade8 device
anticoagulant. The tube was inverted 7 times and then centrifuged
Growth factor
concentration
for 6 minutes at 1 lOOxg. The tube was inverted 7 more times and PDGF-AB (pg/ml)
78.7 ±82.1
23,947 ±11,127
then a CBC on the PRP was collected. The PRP was transferred
TGF-pl (ng/ml)
VEGFJpgtal)
1 1,594 ± 5,977
into a glass vacutainer tube preloaded with calcium chloride. This
TSP-1 (ng/ml)
13,501 ±5,431
tube was inverted 7 times and then centrifuged for 15 minutes at
1450xg. A clot formed in the tube. According to the
manufacturer's instructions, the excess liquid surrounding the clot
is to be discarded. The clot was added to 35 ml of PBS. The
excess liquid was retained for growth factor quantification.
Elution of growth factors from the clots was collected at
time 0, 20 minutes, 1 hr, 4 hr, 24 hr, 72 hr, 120 hr, and 168 hr.
Growth factor content for PDGF-AB, TGF-P1, VEGF, and
thrombospondin (TSP-1) were assayed by ELISA (R&D Systems,
Minneapolis, MN).
Results:
Platelet concentrations for the baseline, Cascade® system, Figures. Clots floating in discard liquid from each Cascade device
and GPS® HI system are compared (Fig. 1). The PRP output from
the Cascade® system contained fewer platelets than the baseline Discussion:
The GPS* HI device concentrates platelets and consequently
sample.
produces a high concentration of growth factors than can be
delivered to a patient compared to the Cascade® device. Platelets
in the GPS® III device do not become activated and release
growth factors until an exogenous activator is added. In contrast,
=• isoo -i
the platelets in the Cascade® device become activated in the glass
tube, and therefore growth factor release begins immediately. The
majority of the growth factors collected using the Cascade®
device end up discarded in the excess solution surrounding the
clot. While it may be true that the Cascade® system is inexpensive
and simple to use, these findings suggest that not only are
platelets not being concentrated, but the end product contains few
Figure 1: Average platelet concentration from both platelet concentration systems growth factors.
and the base sample.
. •
GPS® is a registered trademark of Biomet Manufacturing Corp. in the United States.
Cascade® is a registered trademark of Cascade Medical Enterprises in the United States.
Cascade is distributed by MTF in the United States.