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Sickle cell disease (SCD) is heterogeneous in terms of manifestation severity, even more so when in compound heterozygosity with beta-thalassemia. The aim of the present study was to stratify βSβ+ patient blood samples in a severity-dependent manner. Blood from thirty-two patients with HbS/β-thalassemia compound heterozygosity was examined for several parameters (e.g., hemostasis, inflammation, redox equilibrium) against healthy controls. Additionally, SCD patients were a posteriori (a) categorized based on the L-glutamine dose and (b) clustered into high-/low-RDW subgroups. The patient cohort was characterized by anemia, inflammation, and elevated coagulation. Higher-dose administration of L-glutamine was associated with decreased markers of inflammation and oxidation (e.g., intracellular reactive oxygen species) and an altered coagulation profile. The higher-RDW group was characterized by increased hemolysis, elevated markers of inflammation and stress erythropoiesis, and oxidative phenomena (e.g., membrane-bound hemoglobin). Moreover, the levels of hemostasis parameters (e.g., D-Dimers) were greater compared to the lower-RDW subgroup. The administration of higher doses of L-glutamine along with hydroxyurea seems to attenuate several features in SCD patients, probably by enhancing antioxidant power. Moreover, anisocytosis may alter erythrocytes’ coagulation processes and hemolytic propensity. This results in the disruption of the redox and pro-/anti-inflammatory equilibria, creating a positive feedback loop by inducing stress erythropoiesis and, thus, the occurrence of a mixed erythrocyte population.

Extracellular vesicles (EVs) are membrane-enclosed nanoparticles released by most cells in body fluids and extracellular matrix. They function as signal transducers in intercellular communication, contributing to the maintenance of cell and tissue integrity. EVs biogenesis is deregulated in various pathologies, in structural and functional connection to the pathophysiology of donor cells. Consequently, EVs are considered diagnostic and monitoring factors in many diseases. Despite consensus as to their activity in promoting coagulation and inflammation, there is evidence suggesting protective roles for EVs in stress states. Chronic kidney disease (CKD) patients are at high risk of developing cardiovascular defects. The pathophysiology, comorbidities, and treatment of CKD may individually and in synergy affect extracellular vesiculation in the kidney, endothelium, and blood cells. Oxidative and mechanical stresses, chronic inflammation, and deregulation of calcium and phosphate homeostasis are established stressors of EV release. EVs may affect the clinical severity of CKD by transferring biological response modifiers between renal, vascular, blood, and inflammatory cells. In this Review, we focus on EVs circulating in the plasma of CKD patients. We highlight some recent advances in the understanding of their biogenesis, the effects of dialysis, and pharmacological treatments on them and their potential impact on thrombosis and vascular defects. The strong interest of the scientific community to this exciting field of research may reveal hidden pieces in the pathophysiology of CKD and thus, innovative ways to treat it. Overcoming gaps in EV biology and technical difficulties related to their size and heterogeneity will define the success of the project.

Coagulation abnormalities in renal pathology are associated with a high thrombotic and hemorrhagic risk. This study aims to investigate the hemostatic abnormalities that are related to the interaction between soluble coagulation factors and blood cells, and the effects of hemodialysis (HD) on it, in end stage renal disease (ESRD) patients. Thirty-two ESRD patients under HD treatment and fifteen healthy controls were included in the study. Whole blood samples from the healthy and ESRD subjects were collected before and after the HD session. Evaluation of coagulation included primary and secondary hemostasis screening tests, proteins of coagulation, fibrinolytic and inhibitory system, and ADAMTS-13 activity. Phosphatidylserine (PS) exposure and intracellular reactive oxygen species (iROS) levels were also examined in red blood cells and platelets, in addition to the platelet activation marker CD62P. Platelet function analysis showed pathological values in ESRD patients despite the increased levels of activation markers (PS, CD62P, iROS). Activities of most coagulation, fibrinolytic, and inhibitory system proteins were within the normal range, but HD triggered an increase in half of them. Additionally, the increased baseline levels of ADAMTS-13 inhibitor were further augmented by the dialysis session. Finally, pathological levels of PS and iROS were measured in red blood cells in close correlation with variations in several coagulation factors and platelet characteristics. This study provides evidence for a complex coagulation phenotype in ESRD. Signs of increased bleeding risk coexisted with prothrombotic features of soluble factors and blood cells in a general hyperfibrinolytic state. Hemodialysis seems to augment the prothrombotic potential, while the persisted platelet dysfunction might counteract the increased predisposition to thrombotic events post-dialysis. The interaction of red blood cells with platelets, the thrombus, the endothelium, the soluble components of the coagulation pathways, and the contribution of extracellular vesicles on hemostasis as well as the identification of the unknown origin ADAMTS-13 inhibitor deserve further investigation in uremia.