Figure 3 shows the effects of thrombin on clot formation for a healthy control (figure 3a) and when the PPP was pre-incubated for 10 min with 0.2 ng l−1 O111:B4 LPS (two examples in figure 3b,c). Figure 3d shows the distribution of fibre thicknesses for the 30 individuals, with and without added LPS. The fibre thickness is much more heterogeneous after LPS is added. Clearly, these tiny amounts of LPS are having enormous effects on the clotting process. These kinds of netted structures, which we have also termed ‘dense matted deposits’, were previously seen in inflammatory conditions such as diabetes [37–39], iron overload and stroke [37,40–42]. Typically, healthy fibrin fibre networks form a net where individual fibrin fibres are seen, but with added LPS a matted net develops. There is a significant difference (p < 0.0001) between fibre thickness before and after LPS treatment in the presence of thrombin. Note, though, that the distribution of the fibre thickness in the LPS-treated group varies from very thick to very thin. In some cases, continuous fibre plates are formed, where no individual fibres could be seen or measured. This explains the difference in n between the ‘before’ and ‘after’ treatment (1450 versus 1330 measured fibres). Figure 3.The effect of 0.2 ng l−1 O111:B4 LPS on the morphology of fibrin fibres in the platelet-poor plasma (PPP) of healthy individuals (with added thrombin). (a) Healthy fibres; (b,c) PPP with added LPS. (d) Fibre distribution of the control fibres and of controls with added LPS of 30 individuals. Note: in samples with added LPS, there were areas of matted layers with no visible fibres to measure. Fibres were measured using ImageJ as described in Material and methods.