Philadelphia-negative myeloproliferative neoplasms as disorders marked by cytokine modulation

Background: Cytokines are key immune mediators in physiological and disease processes, whose increased levels have been associated with the physiopathology of hematopoietic malignancies, such as myeloproliferative neoplasms. Methods: This study examined the plasma cytokine profiles of patients with essential thrombocythemia, primary myelofibrosis, polycythemia vera and of healthy subjects, and analyzed correlations with JAK2 V617F status and clinical-hematological parameters. Results: The proinflammatory cytokine levels were increased in myeloproliferative neoplasm patients, and the presence of the JAK2 V617F mutation was associated with high IP-10 levels in primary myelofibrosis patients. Conclusions: Essential thrombocythemia, primary myelofibrosis, and polycythemia vera patients exhibited different patterns of cytokine production, as revealed by cytokine network correlations. Together, these findings suggest that augmented cytokine levels are associated with the physiopathology of myeloproliferative neoplasms.

Cytotoxic and pro-apoptotic action of MjTX-I, a phospholipase A2 isolated from Bothrops moojeni snake venom, towards leukemic cells

Abstract Background Chronic myeloid leukemia (CML) is a BCR-ABL1 + myeloproliferative neoplasm marked by increased myeloproliferation and presence of leukemic cells resistant to apoptosis. The current first-line therapy for CML is administration of the tyrosine kinase inhibitors imatinib mesylate, dasatinib or nilotinib. Although effective to treat CML, some patients have become resistant to this therapy, leading to disease progression and death. Thus, the discovery of new compounds to improve CML therapy is still challenging. Here we addressed whether MjTX-I, a phospholipase A2 isolated from Bothrops moojeni snake venom, affects the viability of imatinib mesylate-resistant Bcr-Abl+ cell lines. Methods We examined the cytotoxic and pro-apoptotic effect of MjTX-I in K562-S and K562-R Bcr-Abl+ cells and in the non-tumor HEK-293 cell line and peripheral blood mononuclear cells, using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and the hypotonic fluorescent solution methods, associated with detection of caspases 3, 8, and 9 activation and poly (ADP-ribose) polymerase (PARP) cleavage. We also analyzed the MjTX-I potential to modulate the expression of apoptosis-related genes in K562-S and K562-R cells. Results MjTX-I decreased the viability of K562-S and K562-R cells by 60 to 65%, without affecting the viability of the non-tumor cells, i.e. it exerted selective cytotoxicity towards Bcr-Abl+ cell lines. In leukemic cell lines, the toxin induced apoptosis, activated caspases 3, 8, and 9, cleaved PARP, downregulated expression of the anti-apoptotic gene BCL-2, and upregulated expression of the pro-apoptotic gene BAD. Conclusion The antitumor effect of MjTX-I is associated with its potential to induce apoptosis and cytotoxicity in Bcr-Abl positive cell lines sensitive and resistant to imatinib mesylate, indicating that MjTX-I is a promising candidate drug to upgrade the CML therapy

Efeito da terapia de reposição hormonal sobre o estado férrico

INTRODUÇÃO: Na literatura, numerosas publicações relatam a determinação do estado férrico em crianças, adolescentes e mulheres em fase reprodutiva, no entanto são raras as pesquisas quanto às alterações do ferro em estoque e eritrograma pós-terapia de reposição hormonal (TRH) em pré-menopausadas e menopausadas. O aumento dos estoques de ferro em mulheres pré-menopausadas e menopausadas pode conduzir à elevação do estresse oxidativo e, conseqüentemente, ao risco de desenvolvimento de câncer e doenças cardiovasculares. OBJETIVO: Avaliar o efeito da TRH sobre o eritrograma e o estado férrico em mulheres na pré-menopausa e na menopausa. MÉTODOS: Foram determinados os eritrogramas e as dosagens de ferro, capacidade total de ligação do ferro a transferrina (CTLF) e ferritina séricas em 30 mulheres no climatério antes e após seis meses de TRH com medroxiprogesterona e estradiol. Os eritrogramas, as dosagens de ferro e CTLF foram determinados por meio da utilização de métodos clássicos, e a ferritina, por quimiluminescência. RESULTADOS: Após o uso da TRH, constataram-se significante redução do número de eritrócitos, elevação dos índices hematimétricos e tendência à diminuição nos níveis de ferro sérico e CTLF. Nenhuma alteração significante nos níveis de ferritina e no índice de saturação de transferrina foi detectada após a TRH. DISCUSSÃO E CONCLUSÃO: No presente estudo não foram encontradas alterações nos parâmetros hematimétricos e no estado férrico que impeçam a utilização da TRH no climatério e na menopausa. Os resultados sugerem que a TRH exerceu efeito benéfico sobre o estado férrico nas mulheres no climatério deste estudo, mantendo os estoques de ferro normais e promovendo a elevação dos índices hematimétricos.<br>BACKGROUND: In literature there are many studies about iron status in children, adolescents and fertile women, but investigations of iron stores and erythrocyte parameters variation after hormone replacement therapy (HRT) are rare. Elevated iron stores, oxidative stress, and estrogen deficiency may place premenopausal and menopausal women in a risk of developing heart disease and cancer. OBJECTIVE: To evaluate the effect of HRT in erythrogram and iron status in premenopausal and menopausal women. METHODS: Hematological indices and iron status were assessed by erythrogram, serum ferritin, iron and transferrin iron-binding capacity (TIBC) in 30 pre- and menopausal women before and after HRT with medroxiprogesterone and estradiol. The blood exam, serum iron and iron-binding capacity were determined by laboratory classic methods, while ferritin was measured by quimiluminescent assay. RESULTS: HRT use was followed by a significant reduction in the absolute number of erythrocyte, an increase of hematimetric indexes and a trend towards a reduction of serum iron levels and TIBC. No alterations on serum ferritin and transferrin saturation index were detected after HRT. DISCUSSION AND CONCLUSION: In the present study, alterations in red cell and iron parameters, which could impair the use of HRT in premenopausal and menopausal women, were not observed. Our results suggest that HRT in premenopausal women are beneficial to iron status, maintaining normal iron stores and promoting elevation of red cells indexes

Philadelphia-negative myeloproliferative neoplasms as disorders marked by cytokine modulation

Background: Cytokines are key immune mediators in physiological and disease processes, whose increased levels have been associated with the physiopathology of hematopoietic malignancies, such as myeloproliferative neoplasms. Methods: This study examined the plasma cytokine profiles of patients with essential thrombocythemia, primary myelofibrosis, polycythemia vera and of healthy subjects, and analyzed correlations with JAK2 V617F status and clinical-hematological parameters. Results: The proinflammatory cytokine levels were increased in myeloproliferative neoplasm patients, and the presence of the JAK2 V617F mutation was associated with high IP-10 levels in primary myelofibrosis patients. Conclusions: Essential thrombocythemia, primary myelofibrosis, and polycythemia vera patients exhibited different patterns of cytokine production, as revealed by cytokine network correlations. Together, these findings suggest that augmented cytokine levels are associated with the physiopathology of myeloproliferative neoplasms. Keywords: Ph-negative myeloproliferative neoplasms, Inflammation, Plasma cytokines, JAK2 V617

Bothrops snake venoms and their isolated toxins, an L-amino acid oxidase and a serine protease, modulate human complement system pathways

Background Activation of the complement system plays an important role in the regulation of immune and inflammatory reactions, and contributes to inflammatory responses triggered by envenomation provoked byBothrops snakes. The present study aimed to assess whether Bothrops jararacussuand Bothrops pirajai crude venoms and their isolated toxins, namely serine protease (BjussuSP-I) and L-amino acid oxidase (BpirLAAO-I), modulate human complement system pathways.Methods Lyophilized venom and toxin samples solubilized in phosphate buffered saline were diluted in appropriate buffers to evaluate their hemolytic activity on the alternative and classical pathways of the complement system. Venom- and toxin-treated normal human serum was added to the erythrocyte suspension, and the kinetic of hemolysis was measured spectrophotometrically at 700 nm. The kinetic 96-well microassay format was used for this purpose. We determined the t ½values (time required to lyse 50 % of target erythrocytes), which were employed to calculate the percentage of inhibition of the hemolytic activity promoted by each sample concentration. To confirm complement system activation, complement-dependent human neutrophil migration was examined using the Boyden chamber model.Results At the highest concentration tested (120 μg/mL), B. jararacussu and B. pirajai crude venoms inhibited the hemolytic activity of the classical pathway (65.3 % and 72.4 %, respectively) more strongly than they suppressed the hemolytic activity of the alternative pathway (14.2 and 13.6 %, respectively). BjussuSP-I (20 μg/mL) did not affect the hemolytic activity of the classical pathway, but slightly decreased the hemolytic activity of the alternative pathway (13.4 %). BpirLAAO-I (50 μg/mL) inhibited 24.3 and 12.4 % of the hemolytic activity of the classical and alternative pathways, respectively. Normal human serum treated with B. jararacussu and B. pirajai crude venoms induced human neutrophil migration at a level similar to that induced by zymosan-activated normal human serum.Conclusion Together, the results of the kinetics of hemolysis and the neutrophil chemotaxis assay suggest that pre-activation of the complement system byB. jararacussu and B. pirajai crude venoms consumes complement components and generates the chemotactic factors C3a and C5a. The kinetic microassay described herein is useful to assess the effect of venoms and toxins on the hemolytic activity of the complement system