Blood oxidative status and selectins plasma levels in healthy donors receiving granulocyte-colony stimulating factor

Effect of Filgrastim on adult male rats' fertility and reproductive performance

Filgrastim is a recombinant protein used in treatment neutropenia caused by myelosuppressive medications for patients with non-myeloid cancer. However, its effect in male fertility is not clear. So, the current work aims to clarify the effect of Filgrastim on the reproductive state in Wistar rats. Eighteen (18) male Wistar rats were divided into three groups (6/each). Group (I) where the rats were injected with 0.5 ml/kg/day of distilled water and served as Control Group. The Group (II) animals received intraperitoneal injection of therapeutic dose of 30.83 mcg/kg/day of Filgrastim for one week. The Group (III) rats received the same dose by the same route of Filgrastim for two weeks. Sera of blood samples were processed for serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone (TS). Semen analysis and resazurine reduction test (RRT) were performed. Assaying for malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) was done. The testes were retrieved for histopathological and immunohistochemical studies for caspase-3 detection. Our results revealed that filgrastim affects sperm morphology, significantly decreased the RRT and the reproductive hormones level, elevated the oxidative stress status and induced several histopathological changes in testes with an increased in immunoexpression of caspase-3 in testes tissues. The results of this work demonstrated that Filgrastim may had a deleterious effect on male fertility.

Safety and efficacy of plerixafor dose escalation for the mobilization of CD34+ hematopoietic progenitor cells in patients with sickle cell disease: interim results

Gene therapy for sickle cell disease is limited by the yield of hematopoietic progenitor cells that can be harvested for transduction or gene editing. We therefore performed a phase I dose-escalation study of the hematopoietic progenitor cell mobilizing agent plerixafor to evaluate the efficacy and safety of standard dosing on peripheral blood CD34⁺ cell mobilization. Of 15 patients enrolled to date, only one was chronically transfused and ten were on hydroxyurea. Of eight patients who achieved a CD34⁺ cell concentration >30 cells/μL, six were on hydroxyurea. There was no clear dose response to increasing plerixafor dosage. There was a low rate of serious adverse events; two patients developed vaso-occlusive crises, at the doses of 80 μg/kg and 240 μg/kg. Hydroxyurea may have contributed to the limited CD34⁺ mobilization by affecting baseline peripheral blood CD34 counts, which correlated strongly with peak peripheral blood CD34 counts. Plerixafor administration did not induce significant increases in the fraction of activated neutrophils, monocytes, or platelets. However, increased neutrophils positive for activated β2 integrin and Mac-1 were associated with serious adverse events. In summary, plerixafor was well tolerated but did not achieve consistent CD34⁺ cell mobilization in this cohort of patients, most of whom were being actively treated with hydroxyurea and only one was chronically transfused. The study will continue with escalation of the dose of plerixafor and modification of hydroxyurea administration. Clinicaltrials.gov identifier: NCT02193191.

Plasma soluble L-selectin in medicated patients with schizophrenia and healthy controls

Immune dysfunction has been implicated in the pathophysiology of schizophrenia. Leukocyte migration to the site of inflammation is a fundamental step of immune response which involves P-, E-, and L-selectins. Elevated selectin levels have been reported in un-medicated first-episode patients with schizophrenia but not in medicated patients with multi-episode schizophrenia. We measured fasting plasma soluble P-, E-, and L-selectin in 39 medicated patients with multi-episode schizophrenia and 19 healthy controls. In patients, psychotic symptom severity and cognitive function were assessed with the Positive and Negative Syndrome Scale (PANSS) and the NIH Toolbox Cognitive Test Battery respectively. C-reactive protein (CRP) and Body Mass Index (BMI) were measured in patients and controls. Comparison of selectin levels between patients and controls was done with t-tests and linear regression. Pearson correlation coefficients between plasma selectins and PANSS and cognitive measures were calculated. Geometric mean plasma soluble L-selectin level was lower in patients compared to controls from unadjusted (606.7 ± 1.2 ng/ml vs. 937.7 ± 1.15 ng/ml, p < 0.001) and adjusted analyses (β = 0.59; CI 0.41 to 0.88, p = 0.011). There was a trend towards higher plasma soluble P-selectin in patients compared to controls (90.4 ± 1.2ng/ml vs. 71.8 ± 1.2ng/ml, p = 0.059) in the unadjusted analysis. There was no association between the selectins and psychotic symptoms or cognitive function in the patients. In addition, the selectins were not significantly associated with CRP or BMI. The limitations of this study include small sample size and unavailability of information on medications and blood cell counts. The potential utility of soluble L-selectin as a biomarker of antipsychotic exposure in patients with schizophrenia and the concomitant change in immune response with the use of antipsychotics should be further evaluated.

Granulocyte colony-stimulating factor (G-CSF) increases histone-complexed DNA plasma levels in healthy volunteers

Granulocyte colony-stimulating factor (G-CSF) is an activator of neutrophil granulocytes. Neutrophil extracellular traps are a defensive mechanism consisting of neutrophils, platelets, DNA, histones and antimicrobial proteins. This study was performed to determine whether G-CSF increases histone-complexed DNA in the plasma of healthy volunteers. In total, 51 healthy volunteers (25 males and 26 females) were treated with G-CSF (18 with 300 µg single dose i.v., 27 with 5 µg/kg s.c. for 4 days) and six participants received a placebo. Histone-complexed DNA was measured by enzyme immunoassay in plasma samples at predefined time points (0, 2, 4, 6, 24 h after single dose, day 1, day 2 and day 5 after repeated doses). Histone levels were quantified by Western blotting. A single dose of G-CSF rapidly increased hc-DNA by about 50 % (p < 0.05 for 2-24 h). After repeated doses the increase was even more pronounced: hc-DNA increased by about 50 % (3.0 ± 0.9, p < 0.001 after 24 h and about fourfold after 96 h (p < 0.001)). A statistical significant increase in histone levels was detected as early as 4 h after G-CSF injection (0.43 ± 0.2 vs. 1.08 ± 0.3 µg/ml; p = 0.034). In the placebo group no significant changes occurred. Moreover, significantly higher levels of hc-DNA were measured in male compared to female subjects (226 ± 43 vs. 84 ± 19, p < 0.001). G-CSF injection substantially increases hc-DNA levels in healthy volunteers. There is a significant gender difference in hc-DNA at the baseline.

Genetic and pharmacological modifications of thrombin formation in apolipoprotein e-deficient mice determine atherosclerosis severity and atherothrombosis onset in a neutrophil-dependent manner

BACKGROUND

Variations in the blood coagulation activity, determined genetically or by medication, may alter atherosclerotic plaque progression, by influencing pleiotropic effects of coagulation proteases. Published experimental studies have yielded contradictory findings on the role of hypercoagulability in atherogenesis. We therefore sought to address this matter by extensively investigating the in vivo significance of genetic alterations and pharmacologic inhibition of thrombin formation for the onset and progression of atherosclerosis, and plaque phenotype determination.

METHODOLOGY/PRINCIPAL FINDINGS

We generated transgenic atherosclerosis-prone mice with diminished coagulant or hypercoagulable phenotype and employed two distinct models of atherosclerosis. Gene-targeted 50% reduction in prothrombin (FII(-/WT):ApoE(-/-)) was remarkably effective in limiting disease compared to control ApoE(-/-) mice, associated with significant qualitative benefits, including diminished leukocyte infiltration, altered collagen and vascular smooth muscle cell content. Genetically-imposed hypercoagulability in TM(Pro/Pro):ApoE(-/-) mice resulted in severe atherosclerosis, plaque vulnerability and spontaneous atherothrombosis. Hypercoagulability was associated with a pronounced neutrophilia, neutrophil hyper-reactivity, markedly increased oxidative stress, neutrophil intraplaque infiltration and apoptosis. Administration of either the synthetic specific thrombin inhibitor Dabigatran etexilate, or recombinant activated protein C (APC), counteracted the pro-inflammatory and pro-atherogenic phenotype of pro-thrombotic TM(Pro/Pro):ApoE(-/-) mice.

CONCLUSIONS/SIGNIFICANCE

We provide new evidence highlighting the importance of neutrophils in the coagulation-inflammation interplay during atherogenesis. Our findings reveal that thrombin-mediated proteolysis is an unexpectedly powerful determinant of atherosclerosis in multiple distinct settings. These studies suggest that selective anticoagulants employed to prevent thrombotic events may also be remarkably effective in clinically impeding the onset and progression of cardiovascular disease.

Cancers predispose neutrophils to release extracellular DNA traps that contribute to cancer-associated thrombosis

Cancer-associated thrombosis often lacks a clear etiology. However, it is linked to a poor prognosis and represents the second-leading cause of death in cancer patients. Recent studies have shown that chromatin released into blood, through the generation of neutrophil extracellular traps (NETs), is procoagulant and prothrombotic. Using a murine model of chronic myelogenous leukemia, we show that malignant and nonmalignant neutrophils are more prone to NET formation. This increased sensitivity toward NET generation is also observed in mammary and lung carcinoma models, suggesting that cancers, through a systemic effect on the host, can induce an increase in peripheral blood neutrophils, which are predisposed to NET formation. In addition, in the late stages of the breast carcinoma model, NETosis occurs concomitant with the appearance of venous thrombi in the lung. Moreover, simulation of a minor systemic infection in tumor-bearing, but not control, mice results in the release of large quantities of chromatin and a prothrombotic state. The increase in neutrophil count and their priming is mediated by granulocyte colony-stimulating factor (G-CSF), which accumulates in the blood of tumor-bearing mice. The prothrombotic state in cancer can be reproduced by treating mice with G-CSF combined with low-dose LPS and leads to thrombocytopenia and microthrombosis. Taken together, our results identify extracellular chromatin released through NET formation as a cause for cancer-associated thrombosis and unveil a target in the effort to decrease the incidence of thrombosis in cancer patients.

Antioxidant intervention: a new method for improving hematopoietic reconstitution capacity of peripheral blood stem cells

In peripheral blood stem cell transplantation, bone marrow hematopoietic stem cells (BM HSCs) are collected as they are released from the hypoxic bone marrow, then infused into peripheral blood with higher oxygen concentration after mobilization. In some cases, in vitro amplification culture under normal oxygen may be required, and homing into the hypoxic bone marrow is further carried out after intravenous re-infusion, thereby resulting in constant changes in the reactive oxygen species (ROS). The high-level ROS can damage the hematopoietic reconstitution capacity of HSCs. Thus, the application of antioxidant intervention in the in vivo mobilization of BM HSC and the in vitro culture process of peripheral blood stem cells may be effective against the negative effects of ROS on BM HSC. Antioxidant intervention may also better protect the hematopoietic reconstitution capacity of HSCs, as well as improve the success rate of transplantation.

Targeting stem cell niches and trafficking for cardiovascular therapy

Regenerative cardiovascular medicine is the frontline of 21st-century health care. Cell therapy trials using bone marrow progenitor cells documented that the approach is feasible, safe and potentially beneficial in patients with ischemic disease. However, cardiovascular prevention and rehabilitation strategies should aim to conserve the pristine healing capacity of a healthy organism as well as reactivate it under disease conditions. This requires an increased understanding of stem cell microenvironment and trafficking mechanisms. Engagement and disengagement of stem cells of the osteoblastic niche is a dynamic process, finely tuned to allow low amounts of cells move out of the bone marrow and into the circulation on a regular basis. The balance is altered under stress situations, like tissue injury or ischemia, leading to remarkably increased cell egression. Individual populations of circulating progenitor cells could give rise to mature tissue cells (e.g. endothelial cells or cardiomyocytes), while the majority may differentiate to leukocytes, affecting the environment of homing sites in a paracrine way, e.g. promoting endothelial survival, proliferation and function, as well as attenuating or enhancing inflammation. This review focuses on the dynamics of the stem cell niche in healthy and disease conditions and on therapeutic means to direct stem cell/progenitor cell mobilization and recruitment into improved tissue repair.

Effects of rhG-CSF Plus Dexamethasone on Hemostatic Parameters in Healthy Granulocyte Donors: Role of u-PA and Nitric Oxide

Granulocyte colony-stimulating factor (G-CSF) is widely used to reduce the risk of infection resulting from neutropenias and to mobilize and collect CD34+ hematopoetic progenitor cells (HPCs) for autologous and allogenic transplantation. The safety of recombinant human G-CSF (rhG-CSF) administration in healthy donors has been investigated in several studies. However, there are limited cumulative data about the effects of rhG-CSF on hemostasis. Hemostatic parameters, including urokinase-type plasminogen activator antigen (u-PA:Ag) and nitric oxide in 17 healthy granulocyte apheresis donors who donated for neutropenic patients were evaluated. rhG-CSF (single dose, 10 μg/kg subcutaneously) and dexamethasone (8 mg, single dose oral) were given to donors 12 hours before granulocyte apheresis. Two blood samples were drawn at time 0 (T0) before rhG-CSF and dexamethasone administration and at time 1 (T1), immediately before the apheresis. A statistically significant rise in coagulant factor VIII (FVIII) and von Willebrand factor (vWF), and slightly rise in u-PA:Ag were observed after G-CSF plus dexamethasone administration. In addition, there were positive correlations between vWF-D-dimer and FVIII-D-dimer. A significant decrease in mean total nitric oxide (NOx), nitrite, and nitrate levels was also found after G-CSF plus dexamethasone administration. Moreover, there was a strong negative correlation between nitrite and D-dimer levels ( r = −0.611; P = .009). Even if partially compensated with u-PA and protein C, increased FVIII and vWF activity, and decreased nitric oxide levels may still partially contribute to progress of thrombosis risk in rhG-CSF plus dexamethasone administered healthy granulocyte donors. Large numbers of healthy donors exposed to G-CSF plus dexamethasone will be needed to evaluate the risk of thrombosis in this population.