Knut Anders Mosevoll

Serum levels of angiogenin, basic fibroblast growth factor and endostatin in patients receiving intensive chemotherapy for acute myelogenous leukemia

Angiogenesis seems to be important both in the pathogenesis of acute myelogenous leukemia (AML) and for the susceptibility of AML blasts to chemotherapy. Recent clinical studies even suggest that antiangiogenic therapy can induce disease control in patients with AML relapse. In this context we have investigated the profile of the systemic component of angiogenic regulation in AML by characterizing the serum levels of (i) the angiogenic regulators angiogenin, basic fibroblast growth factor (bFGF) and endostatin; (ii) the endothelial cell marker soluble (s) E‐selectin. Patients with untreated AML had increased levels of angiogenin, endostatin and sE‐selectin, whereas the levels of bFGF were not significantly altered. The systemic levels of the proangiogenic bFGF, the antiangiogenic endostatin and the endothelial cell marker sE‐selectin showed significant correlations, whereas angiogenin and sE‐selectin levels were not correlated. Furthermore, intensive chemotherapy resulted in decreased systemic levels of the 2 proangiogenic mediators angiogenin and bFGF, whereas endostatin levels remained high after treatment. Although angiogenin normally is a part of the acute phase reaction, its systemic levels were not altered when patients with chemotherapy‐induced cytopenia developed complicating bacterial infections. Our results suggest that intensive chemotherapy can modulate the systemic component of angiogenic regulation in AML patients.

2012 ECS-ECN JUNIOR REVIEW AWARD –The angioregulatory cytokine network in human acute myeloid leukemia – from leukemogenesis via remission induction to stem cell transplantation

Acute myeloid leukemia (AML) is characterized by bone marrow accumulation of immature leukemic blast cells. Conventional AML treatment includes induction chemotherapy to achieve disease control, followed by consolidation therapy with conventional chemotherapy or allogeneic/autologous stem cell transplantation (allo/auto-SCT) to eradicate residual disease. Even younger patients receiving the most intensive treatment have a median, long-term, AML-free survival of only 45-50%, highlighting the need for new treatment strategies. The important role of the bone marrow cytokine network during disease development and treatment is suggested by several observations, including: (i) the increased microvascular density (MVD) in leukemic bone marrow, (ii) experimental evidence of cytokine-mediated crosstalk between leukemic and microvascular endothelial cells, (iii) the prognostic impact of angioregulatory cytokine levels both in patients receiving conventional chemotherapy and allo-SCT, and (iv) the experimental evidence for an antileukemic effect of cytokine inhibition in human AML. Several cytokines are constitutively released by human AML cells, including interleukins, chemokines, vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF) and angiopoietins. However, the cytokine system constitutes a functional, interacting network, and recent evidence suggests that analysis of serum cytokine profiles rather than the analysis of single cytokines should be used for prognostic evaluation of AML patients. We will discuss the role of angioregulatory cytokines in leukemogenesis, including their direct effects on the leukemic cells, as well as their indirect contribution to leukemogenesis through angioregulation and crosstalk between leukemic and neighboring stromal cells. We shall also discuss the possibility of targeting angioregulatory cytokines as a part of the treatment strategy in leukemia.

The Pretransplantation Serum Cytokine Profile in Allogeneic Stem Cell Recipients Differs from Healthy Individuals, and Various Profiles are Associated with Different Risks of Posttransplantation Complications

Cytokines play a key role in regulation of normal and malignant hematopoiesis, angiogenesis, and inflammation. Serum levels of several cytokines are altered in patients with hematologic malignancies, and pretransplant cytokine levels seem to have a prognostic impact in patients treated with allogeneic stem cell transplantation. However, the cytokine system constitutes an interacting functional network, and it may therefore be more relevant to look at serum cytokine profiles rather than the serum levels of single cytokines in allotransplanted patients. We therefore investigated the pretransplantation serum levels of 35 cytokines in a group of 44 consecutive allogeneic stem cell transplantation patients, mainly with a primary diagnosis of acute leukemia. Serum samples were collected before the start of myeloablative conditioning therapy when all patients were in complete hematologic remission. Unsupervised hierarchical clustering analysis identified three major patient groups/subsets. These groups differed especially in the levels of hepatocyte growth factor and granulocyte-colony stimulating factor, and one of the groups was characterized by low early treatment-related morbidity and high levels of hepatocyte growth factor and granulocyte-colony stimulating factor. The degree of weight gain/fluid retention after conditioning therapy did not differ between the patient subsets, but fluid retention showed a significant correlation with pretransplantation serum levels of basic fibroblast growth factor. We conclude that the pretransplantation serum cytokine profile shows a considerable variation even between patients in complete hematologic remission and is associated with clinicopathologic features.

Altered plasma levels of cytokines, soluble adhesion molecules and matrix metalloproteases in venous thrombosis.

BACKGROUND/AIM Recent studies have emphasized the importance of the inflammatory response mediated by monocyte and neutrophil activation in deep venous thrombosis (DVT); we therefore investigated whether this response was reflected in the plasma profile of inflammatory mediators in patients with suspected DVT. METHODS We included a group of 169 consecutive patients admitted to hospital from the primary health care service with suspected lower limb DVT. Plasma levels of 43 mediators were examined for a cohort of 89 consecutive patients and 20 healthy controls by Luminex multiplex analyses, i.e. 13 interleukins, 3 immunomodulatory cytokines, 8 chemokines, 8 growth factors, 3 adhesion molecules and 8 matrix metalloproteases. Selected mediators were analyzed for a second cohort of 80 consecutive patients. RESULTS Thirty-five of 169 (21%) of referred patients were diagnosed with DVT. Only P-selectin (p<0.0001), vascular cell adhesion protein 1 (VCAM-1, p=0.0009), matrix metalloprotease 8 (MMP-8, p=0.0151) and hepatocyte growth factor (HGF, p=0.0415) differed significantly when comparing patients with and without DVT. When comparing DVT patients with healthy controls we observed significant differences for several mediators, where P-selectin (p=0.0009), VCAM-1 (p<0.0001), all the MMPs (all p<0.0014) and HGF (p<0.0001) showed the strongest significant differences. Unsupervised hierarchical clustering analyses based on biomarkers showing differences between patients with and without DVT could be used to identify patient subsets that differed significantly in DVT frequency. CONCLUSION Plasma biomarker profiling of selected soluble mediators can be used to identify subsets among patients with suspected lower limb thrombosis that differ significantly in their frequencies of DVT.

Coordination of Metabolism and Virulence Factors Expression of Extraintestinal Pathogenic Escherichia coli Purified from Blood Cultures of Patients with Sepsis

One of the trademarks of extraintestinal pathogenic Escherichia coli is adaptation of metabolism and basic physiology to diverse host sites. However, little is known how this common human pathogen adapts to permit survival and growth in blood. We used label-free quantitative proteomics to characterize five E. coli strains purified from clinical blood cultures associated with sepsis and urinary tract infections. Further comparison of proteome profiles of the clinical strains and a reference uropathogenic E. coli strain 536 cultivated in blood culture and on two different solid media distinguished cellular features altered in response to the pathogenically relevant condition. The analysis covered nearly 60% of the strains predicted proteomes, and included quantitative description based on label-free intensity scores for 90% of the detected proteins. Statistical comparison of anaerobic and aerobic blood cultures revealed 32 differentially expressed proteins (1.5% of the shared proteins), mostly associated with acquisition and utilization of metal ions critical for anaerobic or aerobic respiration. Analysis of variance identified significantly altered amounts of 47 proteins shared by the strains (2.7%), including proteins involved in vitamin B6 metabolism and virulence. Although the proteomes derived from blood cultures were fairly similar for the investigated strains, quantitative proteomic comparison to the growth on solid media identified 200 proteins with substantially changed levels (11% of the shared proteins). Blood culture was characterized by up-regulation of anaerobic fermentative metabolism and multiple virulence traits, including cell motility and iron acquisition. In a response to the growth on solid media there were increased levels of proteins functional in aerobic respiration, catabolism of medium-specific carbon sources and protection against oxidative and osmotic stresses. These results demonstrate on the expressed proteome level that expression of extraintestinal virulence factors and overall cellular metabolism closely reflects specific growth conditions. Data are available via ProteomeXchange with identifier PXD002912.

Systemic levels of the endothelium-derived soluble adhesion molecules endocan and E-selectin in patients with suspected deep vein thrombosis

The initial evaluation of patients with suspected deep vein thrombosis includes the use of biomarkers reflecting activation of the coagulation system. However, the thromboembolic process and neighboring inflammatory responses also affect endothelial cells, and endothelial cell markers may therefore be altered by the disease. In the present population-based single-center study, we investigated the plasma levels of the endothelium-specific biomarkers soluble E-selectin and endocan in a consecutive and unselected group of 120 patients admitted to hospital for suspected deep vein thrombosis. Blood samples were collected when patients arrived at the hospital. DVT patients showed evidence for an acute phase reaction with increased serum C-reactive protein levels, but this was similar to many other patients admitted with suspected but not verified thrombosis. Plasma endocan and E-selectin levels did not differ between patients with thrombosis, healthy controls and the patients without verified thrombosis (i.e. patients with other causes of their symptoms, including various inflammatory and non-inflammatory conditions). However, the combined use of endothelial biomarkers, C-reactive protein and D-dimer could be used to identify patient subsets with different frequencies of venous thrombosis. Thus, analysis of plasma biomarker profiles including endothelial cell markers may be helpful in the initial evaluation of patients with deep vein thrombosis.

Targeted anti-leukemic therapy as disease-stabilizing treatment for acute myeloid leukemia relapse after allogeneic stem cell transplantation: Will it be possible to combine these strategies with retransplantation or donor lymphocyte infusions?

Allogeneic stem cell transplantation is commonly used in the treatment of high-risk acute myeloid leukemia (AML). This intensive treatment has a high early transplant-related mortality, and an additional significant cause of death in these patients is later AML relapse. Retransplantation can be considered for a minority of patients, but only 10-20% of selected patients then achieve long-term survival. Donor lymphocyte infusion (DLI) has an antileukemic effect, but the effect of this treatment usually lasts for only 3-4 months. A possible strategy to improve the prognosis could be to combine antileukemic T-cell therapy (i.e. DLI) with AML-targeting therapy. Several aspects have to be considered for such approaches: (i) the therapy should have immunomodulatory rather than immunosuppressive effects; (ii) the regimen should have a low hematological toxicity to preserve residual normal bone marrow function; and (iii) the treatment should have a documented antileukemic effect. DLI elicit both graft versus host and graft versus leukemia effects, and could be added to pharmacological treatment. Epigenetic targeting should be considered in these patients because both demethylating agents as well as the histone deacetylase inhibitors have documented antileukemic effects and have a relatively low hematological toxicity. Other drugs to consider are thalidomide, lenalidomide, antiangiogenic agents, tyrosine kinase inhibitors and heat shock protein 90 inhibitors, which all have both antileukemic and immunomodulatory effects. Relatively few clinical studies are available for patients with this high-risk disease. The designs of future clinical trials have to carefully consider the antileukemic and immunomodulatory effects together with the risk of especially hematological toxicity.

Stem cell mobilization and harvesting by leukapheresis alters systemic cytokine levels in patients with multiple myeloma

BACKGROUND AIMS Stem cell mobilization and harvesting by peripheral blood leukapheresis in patients with myeloma can alter plasma levels of certain cytokines. In the present study, we investigated the effects of these interventions on a larger group of cytokines. METHODS Plasma cytokine levels were determined in 15 patients with myeloma who were undergoing peripheral blood stem cell harvesting, and we compared the patients with healthy donors who were undergoing platelet apheresis. RESULTS Several cytokines showed altered levels in patients with myeloma when examined after chemotherapy plus granulocyte colony-stimulating factor-induced stem cell mobilization. The most striking effect was increased levels of several CCL (CCL2/3/4) and CXCL (CXCL5/8/10/11) chemokines as well as increased thrombopoietin, interleukin 1 receptor antagonist, interleukin-4, granulocyte colony-stimulating factor and hepatocyte growth factor. Stem cell harvesting by apheresis altered the plasma levels of several mediators (CD40 ligand, interleukin 1 receptor antagonist, CCL5 and CXCL5/8/10/11). Apheresis in patients with myeloma had divergent effects on these chemokine levels, although they were all still significantly higher than for healthy individuals. Thrombapheresis in healthy individuals had only minor effects on plasma cytokine levels. Stem cell graft supernatants showed high levels of several cytokines, especially CCL and CXCL chemokines. Analyses of chemokine profiles in pre-apheresis plasma and graft supernatants suggested that such profiling can be used to detect prognostically relevant differences between patients. CONCLUSIONS Our results demonstrate that patients with myeloma have an altered cytokine network during stem cell mobilization, and the network is further altered during stem cell harvesting by leukapheresis. These treatment- or procedure-induced alterations involve several mediators known to affect myeloma cell proliferation, migration and survival.

Inflammatory Mediator Profiles Differ in Sepsis Patients With and Without Bacteremia

Systemic levels of cytokines are altered during infection and sepsis. This prospective observational study aimed to investigate whether plasma levels of multiple inflammatory mediators differed between sepsis patients with and those without bacteremia during the initial phase of hospitalization. A total of 80 sepsis patients with proven bacterial infection and no immunosuppression were included in the study. Plasma samples were collected within 24 h of hospitalization, and Luminex® analysis was performed on 35 mediators: 16 cytokines, six growth factors, four adhesion molecules, and nine matrix metalloproteases (MMPs)/tissue inhibitors of metalloproteinases (TIMPs). Forty-two patients (52.5%) and 38 (47.5%) patients showed positive and negative blood cultures, respectively. There were significant differences in plasma levels of six soluble mediators between the two “bacteremia” and “non-bacteremia” groups, using Mann–Whitney U test (p < 0.0014): tumor necrosis factor alpha (TNFα), CCL4, E-selectin, vascular cell adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1), and TIMP-1. Ten soluble mediators also significantly differed in plasma levels between the two groups, with p-values ranging between 0.05 and 0.0014: interleukin (IL)-1ra, IL-10, CCL2, CCL5, CXCL8, CXCL11, hepatocyte growth factor, MMP-8, TIMP-2, and TIMP-4. VCAM-1 showed the most robust results using univariate and multivariate logistic regression. Using unsupervised hierarchical clustering, we found that TNFα, CCL4, E-selectin, VCAM-1, ICAM-1, and TIMP-1 could be used to discriminate between patients with and those without bacteremia. Patients with bacteremia were mainly clustered in two separate groups (two upper clusters, 41/42, 98%), with higher levels of the mediators. One (2%) patient with bacteremia was clustered in the lower cluster, which compromised most of the patients without bacteremia (23/38, 61%) (χ2 test, p < 0.0001). Our study showed that analysis of the plasma inflammatory mediator profile could represent a potential strategy for early identification of patients with bacteremia.

In sepsis, 88% of bacteraemia patients are discriminated by unsupervised hierarchical cluster analysis of 5 inflammatory mediators

A range of cytokines are altered during sepsis. Multiplex analysis of inflammatory mediators makes it easier to study a larger range of mediators, and combined with newer bioinformatical tools (unsupervised hierarchical clustering), this has the potential to bring new knowledge of the inflammatory process during sepsis.