Modification of immunological features in human platelets during sepsis

Abstract

Sepsis is an organic dysfunction that puts at risk the life of patients suffering this disorder due to an exacerbated immunological response to the infection mediated by the host. Platelets have been largely researched on sepsis owing to its role in Disseminated Intracellular Coagulation (DIC) and because thrombocytopenia is an important clinical feature of these patients. Nevertheless, a great number of evidence shows that platelets have also an important role in immunological response since they have pattern recognition receptors, chemokine receptors and granules with stored soluble mediators. In this work, the immunological features of platelets in individuals with sepsis are described. The results show that platelets of these individuals have high levels of surfaces expression of TLR4, CD62P, CD32 and thrombin receptor 1 (PAR-1), these platelets have also greater capability to join Escherichia coli, and show a different profile of soluble mediators (IL-1β, CD40L and TNF-α). Platelets from patients with sepsis form aggregates with neutrophils in circulation, but are unable to induce the production of reactive oxygen species. This research describes important features of platelets to help the understanding of the immunological role of these cells in sepsis.

Escherichia coli-related disseminated intravascular coagulation: Case report and literature review

“…Platelets also activate the coagulation system so that the fibrinogen in plasma is converted to fibrin and, finally, the fibrin network is formed. Thrombocytopenia also mediates inflammation, [4,5] and the immune response. The causes of thrombocytopenia include decreased production, [6] increased consumption, or increased destruction of platelets in the spleen.…”

Intracellular communication and immunothrombosis in sepsis

“…Nevertheless, whether the expression of PAR‐1 on platelets is upregulated in sepsis is unclear. Raque et al 33 reported increased PAR‐1‐positive platelets in patients with sepsis. By contrast, Reiter et al 34 showed a decrease in PAR‐1 on platelets.…”

Recent Advances in the Discovery and Function of Antimicrobial Molecules in Platelets

“…This effect is associated with poor prognosis and, given that neutrophils are also present high numbers in this condition, CHDPs levels are deemed mainly derived from neutrophils secretion [ 154 , 155 , 156 , 157 , 158 ]. On the other hand, platelet activation in sepsis patients is evident by increased CD62P, TLR4, and protease-activated receptor 1 (PAR1) surface expression [ 159 ], as well as an increased hPF4 amount and platelet-derived microparticles [ 160 ]. In this scenario, platelets and megakaryocytes might contribute to these patients’ high CHDPs concentrations and the subsequent multifunctional effects mentioned above.…”