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Chronic inflammation is characterized by the production of reactive oxygen species (ROS), reactive nitrogen species, and inflammatory cytokines in myeloproliferative neoplasms (MPNs). In addition to these parameters, the aim of this study was to analyze the influence of ROS on the pro-liferation-related AKT/mTOR signaling pathway and the relationship with inflammatory factors in chronic myelogenous leukemia (CML). The activity of the antioxidant enzymes superoxide dis-mutase, glutathione peroxidase, and catalase is reduced in erythrocytes while levels of the oxidative stress markers malondialdehyde and protein carbonyl are elevated in the plasma of patients with CML. In addition, nitrogen species (nitrotyrosine, iNOS, eNOS) and inflammation markers (IL-6, NFkB, and S100 protein) were increased in granulocytes of CML while anti-inflammatory levels of IL-10 were decreased in plasma. CML granulocytes exhibited greater resistance to cytotoxic H2O2 activity compared to healthy subjects. Moreover, phosphorylation of the apoptotic p53 protein was reduced while the activity of the AKT/mTOR signaling pathway was increased, which was further enhanced by oxidative stress (H2O2) in granulocytes and erythroleukemic K562 cells. IL-6 caused oxidative stress and DNA damage that was mitigated using antioxidant or inhibition of inflammatory NFkB transcription factor in K562 cells. We demonstrated the presence of oxidative and ni-trosative stress in CML, with the former mediated by AKT/mTOR signaling and stimulated by in-flammation.

The severity and mortality of coronavirus disease 2019 (COVID-19) are greater in males than in females, though the infection rate is the same in the two sexes. We investigated sex hormone differences associated with the hyperinflammatory immune response to SARS-CoV-2 on the basis of patients’ cytokine profiles and vaccination statuses. Clinical and laboratory data of 117 patients with COVID-19 were collected to examine sex differences associated with oxidative stress markers, neutrophil extracellular traps (NETs), and plasma cytokine levels up to 5 months from hospital admission. The testosterone and free testosterone levels were low in male patients with COVID-19 and returned to normal values after recovery from the disease. The dihydrotestosterone (DHT) levels were transiently reduced, while the sex hormone-binding globulin levels were decreased in post-COVID-19 male patients. The levels of the inflammatory cytokines interleukin-6 (IL-6) and IL-10 appeared generally increased at diagnosis and decreased in post-COVID-19 patients. In females, the concentration of tumor necrosis factor-alpha was increased by four times at diagnosis. The levels of the coagulation markers intercellular adhesion molecule-1 (ICAM-1) and E-selectin were consistently upregulated in post-COVID-19 female patients, in contrast to those of vascular cell adhesion molecule-1 (VCAM-1), P-selectin, and chemokine IL-8. DHT increased the levels of reactive oxygen species in the neutrophils of male patients, while estradiol decreased them in females. Markers for NET, such as circulating DNA and myeloperoxidase, were significantly more abundant in the patients’ plasma. Sex hormones have a potential protective role during SARS-CoV-2 infection, which is weakened by impaired testosterone synthesis in men.

Neutrophils are an essential component of the innate immune response, but their prolonged activation can lead to chronic inflammation. Consequently, neutrophil homeostasis is tightly regulated through balance between granulopoiesis and clearance of dying cells. The bone marrow is both a site of neutrophil production and the place they return to and die. Myeloproliferative neoplasms (MPN) are clonal hematopoietic disorders characterized by the mutations in three types of molecular markers, with emphasis on Janus kinase 2 gene mutation (JAK2V617F). The MPN bone marrow stem cell niche is a site of chronic inflammation, with commonly increased cells of myeloid lineage, including neutrophils. The MPN neutrophils are characterized by the upregulation of JAK target genes. Additionally, MPN neutrophils display malignant nature, they are in a state of activation, and with deregulated apoptotic machinery. In other words, neutrophils deserve to be placed in the midst of major events in MPN. Our crucial interest in this review is better understanding of how neutrophils die in MPN mirrored by defects in apoptosis and to what possible extent they can contribute to MPN pathophysiology. We tend to expect that reduced neutrophil apoptosis will establish a pathogenic link to chronic inflammation in MPN.

Background: Oxidative stress is caused by imbalance between excessive production of reactive oxygen species and decreased capabilities of antioxidant system, and it is recognized as a feature in cancerogenesis, as well in hematologic malignancies. Previous studies have shown increasing expression of oxidative stress markers and antioxidant enzymes in lymph nodes progressing to aggressive lymphomas. Aims: The aim of our study was to assess the clinical and prognostic significance of oxidative stress markers in patients with untreated diffuse large B-cell lymphoma (DLBCL). Methods: We analysed 64 patients diagnosed with DLBLC during 2018 and 2019, while 27 healthy volunteers (51.9% males) served as a control group. The plasma sample and laboratory analyses were obtained prior to initiation of specific hematologic treatment. After completion of the therapy, the patients were followed up for up to 4 years and for each of them progression free survival (PFS) and overall survival (OS) were calculated. Malondialdehyde (MDA) and protein carbonyl (PC) were used as markers of oxidative stress in plasma of patients and volunteers, while catalase is used as an antioxidant marker. Results: The mean patients’ age was 56.2 years (range, 20–87); 51.6% were males. Majority of patients were analysed before 1L therapy (n=61; 95,3%), and had following clinical stages: Ann Arbor stage I 23.4%, stage II 37.5%, stage III 15.6% and stage IV 23.4%. Majority of the patients had satisfactory performance status (73.5% had ECOG PS ≥1), bulky tumorous mass was present in 34.4% of patients, whereas 70.3% had extranodal localisation of lymphoma. MDA (6.66±2.7 nmol/ml) was significantly increased (p<0.001, 2.6-fold), while PC (4.29±2.7 nmol/mg) was also significantly increased (p=0.0027, 5-fold) in patients with DLBCL compared to healthy volunteers. In opposite, antioxidant catalase (0.194±0.06 IU/ml) was significantly reduced (p=0.0034, 1.9-fold) in patients with DLBCL. MDA was in significant (p<0

Background. A vascular system inflammation is a risk of venous thromboembolism and can result in widespread microangiopathy with microvascular thrombosis. Methods. We performed laboratory clinical follow-up of patients with COVID-19 to compare gender differences. To study the sex difference in COVID-19 outcome we will measure estradiol and androgens: dihydrotestosterone (DHT) and sex hormone binding globulin (SHBP) in plasma of 63 COVID-19 patients, analyzed by ELISA. Their levels will be correlated to the adhesion molecules: soluble intercellular adhesion molecule 1 (sICAM-1), soluble vascular adhesion molecule 1 (sVCAM-1), sE-selectin, and sP-selectin as biomarkers for inflammation and thrombosis. Results. DHT was increased (1.9 fold) in male COVID-19 patients compared to healthy male volunteers. SHBP was significantly increased in COVID-19 patients compared to healthy volunteers (p<0.05) as well as female vs. male COVID-19 patients (p<0.001, 2.5 fold). sVCAM-1 and sICAM-1 were increased in female COVID-19 patients compared to male COVID-19 patients and female volunteers, respectively (p<0.05). The sP-selection was significantly (p<0.01) increased in male vs. female COVID-19 patients. SHBP was in negative correlation with sP-selectin (p<0.05). DHT was in positive correlation with sVCAM-1 (p<0.05). Ferritin had 3-fold higher levels in male than female COVID-19 patients (p<0.001). Conclusions. Upregulation of androgen hormones and thrombotic biomarkers in COVID-19 patients demonstrate sex dependence.

Background:: Hydroxyurea (HU) is a chemotherapeutic agent that reduces ribonucleotide reductase, stops DNA synthesis and repar, and therefore causes cell proliferation inhibition and apoptosis. Due to its cytostatic properties, HU is frequently used for treatment of myeloproliferative neoplasms, ovarian cancer, and sickle cell anemia. Nitric oxide (NO), produced by nitric oxide synthase (NOS) enzymes is a potent signaling molecule involved in blood flow regulation, neutrotransmission, and immunity. Although HU treatment increases NO levels, up to date it is not clear whether it originates from activation of NOS enzymes or HU degradation. Aims: The aim of this study was to determine the involvement of NOS2 enzyme in the cytostatic effect of HU. Methods: To examine the involvement of the NOS2 enzyme in the molecular mechanism of HU, we treated erythroleukemic HEL92.7.1 cells with pan-selective NOS inhibitor L-NAME (200µM, 1mM, and 5mM), NOS2 specific inhibitor 1400W (1, 10, and 100µM), or NOS2/NOS3 inhibitor DPI (1, 5, and 10µM), in combination with hydroxyurea (200µM), and monitored their effect on proliferation and cell cycle. Immunocytochemistry for the proliferation marker Ki67 was performed to assess proliferation, while cell distribution in cell cycle phases was determined by flow cytometry after propidium iodide staining. Colony forming assay have been performed with the bone marrow cells of Nos2 null mice after oral HU treatment to corroborate the data obtained by enzymatic inhibition. Results: In this study, we demonstrated that treatment of HEL92.7.1 cells with HU induces a dose-dependent increase in NOS2 protein levels and two products of the enzyme NOS - NO and citrulline. HU-induced citrulline levels can be reduced by treatment with the NOS inhibitor L-NAME, indicating that NO is produced de novo by the NOS enzyme rather than HU degradation. Inhibition of the NOS2 enzyme by L-NAME, 1400W, or DPI was sufficient to abolish HU-mediated inhibition of prolifer