High sodium, rather than high blood pressure, induces immune cell activation and renal infiltration in ovariectomized adult Wistar rats.

We used an animal model of salt-sensitive hypertension (SSH) in which ovariectomized (oVx) rats developed hypertension with high salt (HS) intake. Hypertension is accompanied by changes in the percentage of CD4+ T lymphocytes, immune CD45+ cell infiltration into renal tissue, and changes in Na+, K+- ATPase (NKA) expression in both renal tissue and peripheral blood mononuclear cells (PBMCs). To determine whether the observed changes resulted from HS intake, high blood pressure, or both, hydralazine (HDZ) was used to lower blood pressure. The oVx HS rats received two HDZ schedules either to prevent or to treat hypertension. NKA was overexpressed in the kidneys of all oVx groups and in PBMCs of oVx HS rats. This pattern was not altered with HDZ treatment. Changes in CD4+ T lymphocytes and renal infiltration of CD45+ cells were not reversed either. High salt, but not high blood pressure, induces immune cell activation and renal infiltration. Overexpressed NKA is the primary event, and HS is the perturbation to the system in this model of SSH, which resembles the postmenopausal state.

Toll-like receptor expression and functional behavior in platelets from patients with systemic lupus erythematosus.

BACKGROUND: Multiple blood cell abnormalities participate in the development of inflammation in systemic lupus erythematosus (SLE). Although platelets have been suggested as one of these contributors through the release of their content during activation, there are limited specific data about their role as immune players in SLE. MATERIALS AND METHODS: Thirteen SLE patients were included. Flow cytometry was used to measure Toll-like receptors (TLR) 2, 4, and 9 in resting platelets, platelet-activation markers (PAC-1 binding, P-selectin, CD63, and CD40 ligand -L) and platelet-leukocyte aggregates before and after specific TLR stimulation. Soluble CD40L and von Willebrand factor (vWf) release from stimulated platelets was measured using ELISA. RESULTS: In resting conditions, SLE platelets showed normal expression levels of TLR 2, 4 and 9. Platelet surface activation markers, soluble CD40L, and vWf release were normal at baseline and after TLR stimulation. Platelet-monocyte aggregates were elevated in resting conditions in SLE samples and showed only a marginal increase after TLR stimulation, while baseline and stimulated platelet-neutrophil and platelet-lymphocyte aggregates were normal. C-reactive protein levels positively correlated with platelet-monocyte aggregates both at baseline and after stimulation with the TLR-2 agonist PAM3CSK4, suggesting these complexes could reflect the inflammatory activity in SLE. In our cohort, 12 of 13 patients received treatment with hydroxychloroquine (HCQ), a known inhibitor of endosomal activity and a potential inhibitor of platelet activation. The fact that SLE platelets showed an adequate response to TLR agonists suggests that, despite this treatment, they retain the ability to respond to the increased levels of damage-associated molecular patterns (DAMPs), which represent known TLR ligands, present in the circulation of SLE patients. Interestingly, elevated plasma levels of high mobility group box 1 (HMGB1), a classical DAMP, correlated with vWf release from TLR-stimulated platelets, suggesting that HMGB1 may also be released by platelets, thereby creating a positive feedback loop for platelet activation that contributes to inflammation. CONCLUSION: Our study demonstrates normal platelet TLR expression and function together with increased circulating platelet-monocyte aggregates. In addition, a direct correlation was observed between plasma HMGB1 levels and platelet vWf release following TLR2 stimulation. This platelet behavior in a group of patients undergoing HCQ treatment suggests that platelets could play a role in the inflammatory state of SLE.

Niveles de citoquinas megacariocitopoyéticas en pacientes con trombocitemia esencial y su relación con características clínicas y bioquímicas / Megakaryopoietic cytokine levels in patients with essential thrombocythemia and their relationship with clinical and biochemical features

La megacariocitopoyesis y la producción de plaquetas están regidas por factores de transcripción y citoquinas presentes en el microambiente medular. La trombocitemia esencial (TE) es una enfermedad mieloproliferativa crónica caracterizada por aumento del recuento de plaquetas e hiperplasia megacariocítica. En el presente trabajo se evaluaron los niveles de las citoquinas que participan en el desarrollo megacariocítico en plasma de pacientes con TE que se encontraban sin tratamiento y los de trombopoyetina (TPO) antes y durante el tratamiento con anagrelide. Las determinaciones se realizaron por técnica de ELISA. Dentro de las citoquinas involucradas en la etapa de proliferación, los niveles de interleuquina 3 (IL-3) se encontraron aumentados en los pacientes (p=0.0383) respecto al grupo control. Los niveles de factor estimulante de colonias granulocito-macrofágico y stem cell factor fueron normales. Dentro de las citoquinas con acción sobre la maduración megacariocítica, tanto la interleuquina 6 como la interleuquina 11 y la eritropoyetina estuvieron normales. Los niveles de TPO antes del tratamiento no difirieron del grupo control y durante el tratamiento aumentaron de manera no significativa. Los pacientes que presentaron agregación espontánea tuvieron niveles más altos de TPO que los que no lo hicieron (p=0.049). Los niveles de las citoquinas no tuvieron relación con ninguno de los parámetros clínicos ni de laboratorio evaluados. El aumento de los niveles de IL-3 podría contribuir al incremento en la proliferación megacariocítica en este grupo. La presencia simultánea de niveles más altos de TPO y trombocitosis sería un factor predisponente para la ocurrencia de agregación espontánea en los pacientes con TE

Megakaryopoiesis and platelet production are driven by transcription factors and cytokines present in bone marrow environment. Essential thrombocythemia (ET) is a chronic myeloproliferative disorder characterized by high platelet count and megakaryocytic hyperplasia. In the present work we evaluated plasmatic levels of cytokines involved in megakaryocytic development in a group of patients with ET that were not on treatment, as well as thrombopoietin (TPO) levels before and during anagrelide treatment. The assays were carried out using ELISA techniques. Among the cytokines mainly involved in proliferation of megakaryocytic progenitors, interleukin 3 (IL-3) levels were found increased in patients compared to normal controls (p=0.0383). Granulocyte-macrophage colony stimulating factor and stem cell factor levels were normal. Interleukin 6, as well as interleukin 11 and erythropoietin (EPO), cytokines mainly related to megakaryocytic maturation, were normal. Plasma TPO levels before treatment were within the normal range and increased during treatment but the difference was not statistically significant. Patients who displayed spontaneous platelet aggregation had higher plasma TPO levels compared to those who did not (p=0.049). We did not find any relationship between cytokine levels and clinical or laboratory parameters. The high IL-3 levels seen in some patients with ET could contribute to megakaryocytic proliferation. The simultaneous occurrence of higher TPO levels and elevated platelet count could be a predisposing factor for the development of spontaneous platelet aggregation in ET patients