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. 2018 May 27;16(7):1391–1401. doi: 10.1111/jth.14128

Figure 4.

Figure 4

Effect of recombinant Factor XIIIA and fragments on turbidity and clot lysis. Polymerisation of FXIIIA depleted fibrinogen was initiated by the addition of thrombin, CaCl2, and either full length rFXIIIA (black square), fragment TB1 (lacking barrel 2; dark grey diamond), TCC (lacking barrels 1 and 2; mid‐grey triangle), TBS (lacking catalytic core and barrels 1 and 2; light grey circles), or a control (buffer; very light grey crosses). Generation of turbidity was measured every 12 s for 60 min and results shown are mean values of triplicate experiments (A). Only clots with full‐length FXIII‐A had a significant decrease in final maximum absorbance compared to control (n = 3, P < 0.05). The truncations did not show any significant difference from the control (n = 3, P > 0.05). Clots were also formed in either uncoated Ibidi μ‐Slides for studies with confocal microscopy (B) or in a chandler loop system (C–D) using the same conditions as for the turbidity experiments. Lysis was initiated by the addition of plasminogen and tPA. In confocal microscopy (B), the clot was visualised under a low magnification every 20 s and the time taken for the lysis front to migrate from a fixed point was measured. Lysis front velocity was determined and used to calculate the mean overall lysis rate in μm/sec ± SEM of triplicate clots. In the chandler loop system (C–D), samples of the supernatant were taken every 30 min and the released fluorescence was measured at excitation of 494 nm and emission of 519 nm to determine average relative fluorescent units (RFU) for each time point ± SEM of triplicate experiments. For both confocal microscopy and Chandler loop methods, only clots formed with full‐length FXIII‐A had a significant decrease in fibrinolysis rate compared to control (n = 3, P < 0.05). The truncations did not show any significant difference from the control in either method (n = 3, P > 0.05). FXIIIA, full length FXIII A subunit; TB1, full length FXIII A subunit lacking barrel 2; TBS, full length FXIII A subunit lacking barrels 1 and 2, and catalytic core; TCC, full length FXIII A subunit lacking barrels 1 and 2.