Iodine contrast agents do not influence Platelet-Rich Plasma function at an early time point in vitro

Abstract

Background: Iodine contrast agents (ICAs) are routinely used by radiologists to help guide intra-articular infiltrations. The aim of this study was to assess the in vitro effects of ICA on platelet function of human autologous Platelet-Rich Plasma (PRP).

Methods: One hundred thirty-seven consecutive patients with symptomatic femoral-patellar osteoarthritis were included. All were addressed to our institution for a fluoroscopy-guided intra-articular PRP infiltration of the pathological femoral-patellar joint. For each patient, 500 μl of PRP were sampled before intra-articular injection. First, PRP samples were mixed with 50 μl of 2 widely used ICA: Visipaque270® (Iodixanol, n = 58) and Iopamiron200® (Iopamidol, n = 69). PRP concentration ([PRP]) was measured at different delays of incubation (t = 0, 5, 10, 15, 20 and 30 min) enabling to calculate PRP ratio (defined as [PRP](t)/[PRP](0mn)) at each delay, for each mixture, in order to quantitatively assess the influence of ICA on PRP ratio. Second, the PRP samples of 10 additional patients were mixed with Visipaque270®, Visipaque270®, Iopamiron200® and phosphate buffer saline (PBS: control solution) in order to qualitatively assess the influence of ICA on platelet aggregation, using ADP, Collagen, Arachidonic acid and TRAP tests. The surface expression of human P-selectin, a marker of α-granule release, in the PRP + Visipaque270® and PRP + Iopamiron200® mixtures was finally compared. Repeated-measures ANOVA, classical 2-way ANOVA and Wilcoxon matched-pairs test were used to study the influence of ICA on PRP quality.

Results: There was no significant change in PRP ratio during the first 30mn of incubation (p = 0.991) whatever the ICA (p = 0.926). Whatever the aggregation test, there was no significant difference in the percentage of platelet aggregation between PRP + PBS, PRP + Visipaque270® and PRP + Iopamiron200® (p = 0.998), nor between PRP + PBS and PRP + Visipaque320® (p = 0.470). Finally, there was no significant difference in P-selectin expression between the PRP + Visipaque270® and PRP + Iopamiron200® mixtures (p = 0.500).

Conclusion: At early delays of incubation, Visipaque® and Iopamiron®, which are two widely used ICA for intra-articular infiltrations, did not influence the in vitro platelet function nor the quality of PRP.

Keywords: Arthritis; Intra-articular infiltration; Iodine contrast agent; Platelet.

Fig. 1

In Vitro quantitative assessment. aInitial PRP concentration in the samples (t = 0), in the presence of Visipaque270® and Iopamiron200®. b Evolution of PRP ratio as a function of time (5 incubation delays: 5, 10, 15, 20, 30mn), for each contrast agent group (Visipaque270® and Iopamiron200®). c Morphological aspect of platelets before and after exposure to iodine contrast agent: no change was seen

Fig. 2

In Vitro qualitative assessment. a Platelet aggregation depending on the iodine contrast agent. Three groups were compared: control (PRP + phosphate buffer solution), Visipaque270® (PRP + Visipaque270®) and Iopamiron200® (PRP+ Iopamiron200®) (b) Platelet aggregation depending on the iodine concentration of Visipaque®. Two groups were compared: control (PRP + phosphate buffer solution) and Visipaque320®. The percentage of platelet aggregation was assessed by 4 tests: in the presence of adenosine diphosphate (ADP), Collagen, Arachidonic acid (Ar. acid) and thrombin receptor activating peptide (TRAP). c Degranulation: Surface expression of human P-selectin in the presence of PRP + Visipaque270® or PRP + Iopamiron200®, before and after exposure to 25 μM of TRAP. P selectin expression is expressed as the mean fluorescence intensity compare to normal. P-selectin expression ratio corresponds to the ratio between expression after TRAP exposure and before TRAP exposure