uu.seUppsala University Publications
Change search
Link to record
Permanent link

Direct link
BETA
Hamad, Osama A.
Publications (10 of 15) Show all publications
Gustafson, E. K., Hamad, O. A., Deckmyn, H., Barbu, A. R., Ekdahl, K. N. & Nilsson, B. (2019). Exposure of von Willebrand Factor on Isolated Hepatocytes Promotes Tethering of Platelets to the Cell Surface. Transplantation, 103(8), 1630-1638
Open this publication in new window or tab >>Exposure of von Willebrand Factor on Isolated Hepatocytes Promotes Tethering of Platelets to the Cell Surface
Show others...
2019 (English)In: Transplantation, ISSN 0041-1337, E-ISSN 1534-6080, Vol. 103, no 8, p. 1630-1638Article in journal (Refereed) Published
Abstract [en]

Background. Hepatocyte transplantation (Hctx) is a potentially attractive method for the treatment of acute liver failure and liver-based metabolic disorders. Unfortunately, the procedure is hampered by the instant blood-mediated inflammatory reaction (IBMIR), a thromboinflammatory response elicited by the vascular innate immune system, causing activation of the coagulation and complement systems and clearance of transplanted cells. Observations have also revealed platelets adhered to the surface of the hepatocytes (Hc). To establish Hctx as a clinical treatment, all factors that trigger IBMIR need to be identified and controlled. This work explores the expression of von Willebrand factor (VWF) on isolated Hc resulting in tethering of platelets. Methods. VWF on Hc was studied by flow cytometry, confocal microscopy, immunoblot, and real-time polymerase chain reaction. Interaction between Hc and platelets was studied in a Chandler loop model. Adhesion of platelets to the hepatocyte surface was demonstrated by flow cytometry and confocal microscopy. Results. Isolated Hc constitutively express VWF on their cell surface and mRNA for VWF was found in the cells. Hc and platelets, independently of coagulation formed complexes, were shown by antibody blocking studies to be dependent on hepatocyte-associated VWF and platelet-bound glycoprotein Ib alpha. Conclusions. VWF on isolated Hc causes, in contact with blood, adhesion of platelets, which thereby forms an ideal surface for coagulation. This phenomenon needs to be considered in hepatocyte-based reconstitution therapy and possibly even in other settings of cell transplantation.

Place, publisher, year, edition, pages
LIPPINCOTT WILLIAMS & WILKINS, 2019
National Category
Hematology
Identifiers
urn:nbn:se:uu:diva-393629 (URN)10.1097/TP.0000000000002707 (DOI)000480691100024 ()30896677 (PubMedID)
Available from: 2019-09-26 Created: 2019-09-26 Last updated: 2019-09-26Bibliographically approved
Nilsson Ekdahl, K., Davoodpour, P., Ekstrand-Hammarström, B., Fromell, K., Hamad, O. A., Hong, J., . . . Nilsson, B. (2018). Contact (kallikrein/kinin) system activation in whole human blood induced by low concentrations of α-Fe2O3 nanoparticles.. Nanomedicine: Nanotechnology, Biology and Medicine, 14(3), 735-744
Open this publication in new window or tab >>Contact (kallikrein/kinin) system activation in whole human blood induced by low concentrations of α-Fe2O3 nanoparticles.
Show others...
2018 (English)In: Nanomedicine: Nanotechnology, Biology and Medicine, ISSN 1549-9634, E-ISSN 1549-9642, Vol. 14, no 3, p. 735-744Article in journal (Refereed) Published
Abstract [en]

Iron-oxide nanoparticles (NPs) generated by environmental events are likely to represent health problems. alpha-Fe2O3 NPs were synthesized, characterized and tested in a model for toxicity utilizing human whole blood without added anticoagulant. MALDI-TOF of the corona was performed and activation markers for plasma cascade systems (complement, contact and coagulation systems), platelet consumption and release of growth factors, MPO, and chemokine/cytokines from blood cells were analyzed. The coronas formed on the pristine alpha-Fe2O3 NPs contained contact system proteins and they induced massive activation of the contact (kinin/kallikrein) system, as well as thrombin generation, platelet activation, and release of two pro-angiogeneic growth factors: platelet-derived growth factor and vascular endothelial growth factor, whereas complement activation was unaffected. The alpha-Fe2O3 NPs exhibited a noticeable toxicity, with kinin/kallikrein activation, which may be associated with hypotension and long-term angiogenesis in vivo, with implications for cancer, arteriosclerosis and pulmonary disease.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
α-Fe2O3, NPsContact/kallikrein system, Innate immunity
National Category
Immunology in the medical area Nano Technology
Identifiers
urn:nbn:se:uu:diva-343471 (URN)10.1016/j.nano.2017.12.008 (DOI)000429528900010 ()
Funder
Swedish Research Council, 2014-3938 2016-2075-5.1 2016-01060 2016-04519EU, FP7, Seventh Framework Programme, 602699AFA Insurance
Note

Joint and equal contribution to senior authorship by Kristina N. Ekdahl, Padideh Davoodpour and Bo Nilsson

Available from: 2018-02-27 Created: 2018-02-27 Last updated: 2019-12-14Bibliographically approved
Fromell, K., Johansson, U., Dührkop, C., Adler, A., Usterud, E., Hamad, O. A., . . . Nilsson, B. (2018). Generation of an alternative pathway convertase by contact-activated C3 is dependent on the conformation of C3. Paper presented at 27th International Complement Workshop (ICW), SEP 16-20, 2018, Santa Fe, New Mexico, USA.. Molecular Immunology, 102, 193-193
Open this publication in new window or tab >>Generation of an alternative pathway convertase by contact-activated C3 is dependent on the conformation of C3
Show others...
2018 (English)In: Molecular Immunology, ISSN 0161-5890, E-ISSN 1872-9142, Vol. 102, p. 193-193Article in journal, Meeting abstract (Other academic) Published
Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2018
Keywords
Complement C3
National Category
Immunology Biochemistry and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-365114 (URN)10.1016/j.molimm.2018.06.167 (DOI)000445313600163 ()
Conference
27th International Complement Workshop (ICW), SEP 16-20, 2018, Santa Fe, New Mexico, USA.
Available from: 2018-11-15 Created: 2018-11-15 Last updated: 2019-12-14Bibliographically approved
Knabl, L., Berktold, M., Hamad, O. A., Fromell, K., Chatterjee, S., Speth, C., . . . Orth-Holler, D. (2018). Shiga toxin 2a binds antithrombin and heparin, but does not directly activate platelets. International Journal of Medical Microbiology, 308(7), 969-976
Open this publication in new window or tab >>Shiga toxin 2a binds antithrombin and heparin, but does not directly activate platelets
Show others...
2018 (English)In: International Journal of Medical Microbiology, ISSN 1438-4221, E-ISSN 1618-0607, Vol. 308, no 7, p. 969-976Article in journal (Refereed) Published
Abstract [en]

Escherichia coli-induced hemolytic uremic syndrome (eHUS) is a life-threatening complication of infection with Shiga toxin (Stx), in particular Stx2a-producing Escherichia coli. Enhanced coagulation activation with formation of microthrombi seems to be a key event in development of eHUS. Platelet activation has been postulated as a possible, but controversially debated mechanism. The present study investigated the effect of Stx2a on plasmatic coagulation and platelets. Binding studies were initially performed with ELISA and co-immunoprecipitation and supported by quartz crystal microbalance with dissipation monitoring (QCM-D). Antithrombin (AT) activity was measured using the automated BCS XP (R) system. ROTEM (R) was used for functional coagulation testing. Platelet binding and activation was studied with FACS and light-transmission aggregometry. We found binding of Stx2a to AT, an important inhibitor of blood coagulation, but only a mild albeit significant reduction of AT activity against FXa in the presence of Stx2a. QCM-D analysis also showed binding of Stx2a to heparin and an impaired binding of AT to Stx2a-bound heparin. ROTEM (R) using Stx2a-treated platelet-poor plasma revealed a significant, but only moderate shortening of clotting time. Neither binding nor activation of platelets by Stx2a could be demonstrated. In summary, data of this study suggest that Stx2a binds to AT, but does not induce major effects on plasmatic coagulation. In addition, no interaction with platelets occurred. The well-known non-beneficial administration of heparin in eHUS patients could be explained by the interaction of Stx2a with heparin.

Keywords
Stx2a, Hemolytic uremic syndrome, Plasmatic coagulation, Antithrombin
National Category
Cell and Molecular Biology
Identifiers
urn:nbn:se:uu:diva-369763 (URN)10.1016/j.ijmm.2018.07.008 (DOI)000448628100027 ()30064820 (PubMedID)
Available from: 2018-12-17 Created: 2018-12-17 Last updated: 2019-12-14Bibliographically approved
Nilsson Ekdahl, K., Teramura, Y., Hamad, O. A., Asif, S., Dührkop, C., Fromell, K., . . . Nilsson, B. (2016). Dangerous liaisons: complement, coagulation, and kallikrein/kinin cross-talk act as a linchpin in the events leading to thromboinflammation. Immunological Reviews, 274(1), 245-269
Open this publication in new window or tab >>Dangerous liaisons: complement, coagulation, and kallikrein/kinin cross-talk act as a linchpin in the events leading to thromboinflammation
Show others...
2016 (English)In: Immunological Reviews, ISSN 0105-2896, E-ISSN 1600-065X, Vol. 274, no 1, p. 245-269Article in journal (Refereed) Published
Abstract [en]

Innate immunity is fundamental to our defense against microorganisms. Physiologically, the intravascular innate immune system acts as a purging system that identifies and removes foreign substances leading to thromboinflammatory responses, tissue remodeling, and repair. It is also a key contributor to the adverse effects observed in many diseases and therapies involving biomaterials and therapeutic cells/organs. The intravascular innate immune system consists of the cascade systems of the blood (the complement, contact, coagulation, and fibrinolytic systems), the blood cells (polymorphonuclear cells, monocytes, platelets), and the endothelial cell lining of the vessels. Activation of the intravascular innate immune system in vivo leads to thromboinflammation that can be activated by several of the system's pathways and that initiates repair after tissue damage and leads to adverse reactions in several disorders and treatment modalities. In this review, we summarize the current knowledge in the field and discuss the obstacles that exist in order to study the cross-talk between the components of the intravascular innate immune system. These include the use of purified in vitro systems, animal models and various types of anticoagulants. In order to avoid some of these obstacles we have developed specialized human whole blood models that allow investigation of the cross-talk between the various cascade systems and the blood cells. We in particular stress that platelets are involved in these interactions and that the lectin pathway of the complement system is an emerging part of innate immunity that interacts with the contact/coagulation system. Understanding the resulting thromboinflammation will allow development of new therapeutic modalities.

Keywords
coagulation, complement system, contact activation/kallikrein system, innate immunity, platelets, thromboinflammation
National Category
Clinical Medicine
Identifiers
urn:nbn:se:uu:diva-373992 (URN)10.1111/imr.12471 (DOI)000387059600017 ()27782319 (PubMedID)
Funder
Swedish Research Council, 2013‐65X‐05647‐34‐4EU, FP7, Seventh Framework Programme, 602699The Swedish Foundation for International Cooperation in Research and Higher Education (STINT)Novo Nordisk
Available from: 2019-01-17 Created: 2019-01-17 Last updated: 2019-12-14Bibliographically approved
Engberg, A. E., Nilsson, P. H., Huang, S., Fromell, K., Hamad, O. A., Mollnes, T. E., . . . Ekdahl, K. N. (2015). Prediction of inflammatory responses induced by biomaterials in contact with human blood using protein fingerprint from plasma. Biomaterials, 36, 55-65
Open this publication in new window or tab >>Prediction of inflammatory responses induced by biomaterials in contact with human blood using protein fingerprint from plasma
Show others...
2015 (English)In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 36, p. 55-65Article in journal (Refereed) Published
Abstract [en]

Inappropriate complement activation is often responsible for incompatibility reactions that occur when biomaterials are used. Complement activation is therefore a criterion included in legislation regarding biomaterials testing. However, no consensus is yet available regarding appropriate complement-activation-related test parameters. We examined protein adsorption in plasma and complement activation/cytokine release in whole blood incubated with well-characterized polymers. Strong correlations were found between the ratio of C4 to its inhibitor C4BP and generation of 10 (mainly pro-inflammatory) cytokines, including IL-17, IFN-gamma, and IL-6. The levels of complement activation products correlated weakly (C3a) or not at all (C5a, sC5b-9), confirming their poor predictive values. We have demonstrated a direct correlation between downstream biological effects and the proteins initially adhering to an artificial surface after contact with blood. Consequently, we propose the C4/C4BP ratio as a robust, predictor of biocompatibility with superior specificity and sensitivity over the current gold standard.

Keywords
Biomaterials, C4 binding protein (C4BP), Complement, Cytokines, Inflammation, In vitro screening
National Category
Biomaterials Science
Identifiers
urn:nbn:se:uu:diva-240199 (URN)10.1016/j.biomaterials.2014.09.011 (DOI)000345728200006 ()25292422 (PubMedID)
Available from: 2015-01-07 Created: 2015-01-06 Last updated: 2019-12-14Bibliographically approved
Ekdahl, K. N., Hamad, O. A., Mitroulis, I., Fromell, K., Chavakis, T., Ricklin, D., . . . Nilsson, B. (2014). Contact activation of C3 enables tethering between activated platelets and polymorphonuclear leukocytes via CD11b/CD18. Paper presented at 25th International Complement Workshop, SEP 14-18, 2014, Rio de Janeiro, BRAZIL. Molecular Immunology, 61(2), 242-243
Open this publication in new window or tab >>Contact activation of C3 enables tethering between activated platelets and polymorphonuclear leukocytes via CD11b/CD18
Show others...
2014 (English)In: Molecular Immunology, ISSN 0161-5890, E-ISSN 1872-9142, Vol. 61, no 2, p. 242-243Article in journal, Meeting abstract (Other academic) Published
National Category
Immunology in the medical area
Identifiers
urn:nbn:se:uu:diva-235589 (URN)000342265300093 ()
Conference
25th International Complement Workshop, SEP 14-18, 2014, Rio de Janeiro, BRAZIL
Available from: 2014-11-06 Created: 2014-11-06 Last updated: 2019-12-14Bibliographically approved
Moll, G., Alm, J. J., Davies, L. C., von Bahr, L., Heldring, N., Stenbeck-Funke, L., . . . Le Blanc, K. (2014). Do Cryopreserved Mesenchymal Stromal Cells Display Impaired Immunomodulatory and Therapeutic Properties?. Stem Cells, 32(9), 2430-2442
Open this publication in new window or tab >>Do Cryopreserved Mesenchymal Stromal Cells Display Impaired Immunomodulatory and Therapeutic Properties?
Show others...
2014 (English)In: Stem Cells, ISSN 1066-5099, E-ISSN 1549-4918, Vol. 32, no 9, p. 2430-2442Article in journal (Refereed) Published
Abstract [en]

We have recently reported that therapeutic mesenchymal stromal cells (MSCs) have low engraftment and trigger the instant blood mediated inflammatory reaction (IBMIR) after systemic delivery to patients, resulting in compromised cell function. In order to optimize the product, we compared the immunomodulatory, blood regulatory, and therapeutic properties of freeze-thawed and freshly harvested cells. We found that freeze-thawed MSCs, as opposed to cells harvested from continuous cultures, have impaired immunomodulatory and blood regulatory properties. Freeze-thawed MSCs demonstrated reduced responsiveness to proinflammatory stimuli, an impaired production of anti-inflammatory mediators, increased triggering of the IBMIR, and a strong activation of the complement cascade compared to fresh cells. This resulted in twice the efficiency in lysis of thawed MSCs after 1 hour of serum exposure. We found a 50% and 80% reduction in viable cells with freshly detached as opposed to thawed in vitro cells, indicating a small benefit for fresh cells. In evaluation of clinical response, we report a trend that fresh cells, and cells of low passage, demonstrate improved clinical outcome. Patients treated with freshly harvested cells in low passage had a 100% response rate, twice the response rate of 50% observed in a comparable group of patients treated with freeze-thawed cells at higher passage. We conclude that cryobanked MSCs have reduced immunomodulatory and blood regulatory properties directly after thawing, resulting in faster complement-mediated elimination after blood exposure. These changes seem to be paired by differences in therapeutic efficacy in treatment of immune ailments after hematopoietic stem cell transplantation.

Keywords
Bone marrow stromal cells, Cellular therapy, Clinical translation, Cryopreservation, Immunotherapy, Engraftment, Instant blood-mediated inflammatory reaction
National Category
Cancer and Oncology Hematology Medical Biotechnology
Identifiers
urn:nbn:se:uu:diva-233006 (URN)10.1002/stem.1729 (DOI)000341294500013 ()
Funder
Swedish Cancer Society, 11 0315Swedish Research Council, 6076170Vinnova, 2010-00501
Available from: 2014-10-10 Created: 2014-09-29 Last updated: 2019-12-14Bibliographically approved
Nilsson, B., Kozarcanin, H., Lood, C., Munthe-Fog, L., Hamad, O. A., Bengtsson, A., . . . Ekdahl, K. N. (2014). The lectin complement pathway serine proteases (MASPs) represent the crossroad between activation of the coagulation and complement systems. Paper presented at 25th International Complement Workshop, SEP 14-18, 2014, Rio de Janeiro, BRAZIL. Molecular Immunology, 61(2), 218-219
Open this publication in new window or tab >>The lectin complement pathway serine proteases (MASPs) represent the crossroad between activation of the coagulation and complement systems
Show others...
2014 (English)In: Molecular Immunology, ISSN 0161-5890, E-ISSN 1872-9142, Vol. 61, no 2, p. 218-219Article in journal, Meeting abstract (Other academic) Published
National Category
Immunology in the medical area
Identifiers
urn:nbn:se:uu:diva-235587 (URN)000342265300024 ()
Conference
25th International Complement Workshop, SEP 14-18, 2014, Rio de Janeiro, BRAZIL
Available from: 2014-11-06 Created: 2014-11-06 Last updated: 2019-12-14Bibliographically approved
Hamad, O. A., Ekdahl, K. N. & Nilsson, B. (2012). Non-proteolytically activated C3 promotes binding of activated platelets and platelet-derived microparticles to leukocytes via CD11b/CD18. Paper presented at Aegean Conferences, XXIV International Complement Workshop, 10-15 October, 2012, Chania, Crete, GREECE. Immunobiology, 217(11), 1191-1191
Open this publication in new window or tab >>Non-proteolytically activated C3 promotes binding of activated platelets and platelet-derived microparticles to leukocytes via CD11b/CD18
2012 (English)In: Immunobiology, ISSN 0171-2985, E-ISSN 1878-3279, Vol. 217, no 11, p. 1191-1191Article in journal, Meeting abstract (Refereed) Published
Abstract [en]

Background:

We have previously demonstrated that complement component C3 binds to the surface of activated platelets, independent of proteolytic activation. The resulting form of C3, termed C3(H2O), was shown to be a ligand for recombinant CD35 (complement receptor 1, CR1). Previous studies by others have indicated that platelet-leukocyte complex (PLC) formation is dependent on the interaction between platelet exposed P-selectin (CD62P) and its ligand, PSGL-1, on leukocytes. In addition, CD11b/CD18 (Mac-1 or CR3) has been shown to participate in this reaction, but its ligand has not yet been identified.

Objective:

To test the hypothesis that C3 bound to activated platelets and platelet-derived microparticles (PMPs) can act as a ligand for CD11b/CD18 (CR3) and contribute to PLC formation.

Methods and results:

Blood cells were depleted of plasma proteins. After extensive washing, C3 was added, and the leukocytes were activated with C5a and the platelets with thrombin receptor-activating peptide (TRAP). PLC formation was detected by flow cytometry (monocytes: CD14+/CD42a+, granulocytes: CD16+/CD42a+). For both granulocytes and monocytes, the addition of C3 significantly enhanced PLC formation. Formation of PLC was inhibited by both anti-P-selectin and anti-CD11b monoclonal antibodies. In addition, PMPs isolated from serum, were found to expose C3(H2O) and bind to leukocytes in a fashion similar to activated platelets.

Conclusion:

We have identified proteolytically non-activated C3 as a ligand for CD11b in the formation of PLC and possibly the binding of PMPs to leukocytes. This observation most likely has pathophysiological implications for the recently reported links between thrombotic disease and the complement system.

Keywords
platelet activation, complement, platelet-leukocyte complexes, PMP, CD11b/CD18, complement component 3
National Category
Immunology in the medical area
Research subject
Clinical Immunology
Identifiers
urn:nbn:se:uu:diva-123624 (URN)10.1016/j.imbio.2012.08.178 (DOI)000311187800190 ()
Conference
Aegean Conferences, XXIV International Complement Workshop, 10-15 October, 2012, Chania, Crete, GREECE
Projects
platelet mediated complement activation
Available from: 2010-04-28 Created: 2010-04-28 Last updated: 2018-01-12Bibliographically approved
Organisations

Search in DiVA

Show all publications