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Papers by Erik Hack

Apoptosis, May 8, 2009

During acute myocardial infarction (AMI), ischemia leads to necrotic areas surrounded by border z... more During acute myocardial infarction (AMI), ischemia leads to necrotic areas surrounded by border zones of reversibly damaged cardiomyocytes, showing membrane flip-flop. During reperfusion type IIA secretory phopholipase A 2 (sPLA 2 -IIA) induces direct cell-toxicity and facilitates binding of other inflammatory mediators on these cardiomyocytes. Therefore, we hypothesized that the specific sPLA 2 -IIA-inhibitor PX-18 would reduce cardiomyocyte death and infarct size in vivo. Wistar rats were treated with PX-18 starting minutes after reperfusion, and at day 1 and 2 post AMI. After 28 days hearts were analyzed. Furthermore, the effect of PX-18 on membrane flipflop and apoptosis was investigated in vitro. PX-18 significantly inhibited sPLA 2 -IIA activity and reduced infarct size (reduction 73 ± 9%, P \ 0.05), compared to the vehicle-treated group, without impairing wound healing. In vitro, PX-18 significantly reduced reversible membrane flip-flop and apoptosis in cardiomyocytes. However, no sPLA 2 -IIA activity could be detected, suggesting that PX-18 also exerted a protective effect independent of sPLA 2 -IIA. In conclusion, PX-18 is a potent therapeutic to reduce infarct size by inhibiting sPLA 2 -IIA, and possibly also by inhibiting apoptosis of cardiomyocytes in a sPLA 2 -IIA independent manner.

J Leukocyte Biol, 2005

␣ 1 -Acid glycoprotein (AGP) is a major acute-phase protein present in human plasma as well as in... more ␣ 1 -Acid glycoprotein (AGP) is a major acute-phase protein present in human plasma as well as in polymorphonuclear leukocytes (PMN). In this report, we show that PMN synthesize a specific glycoform of AGP, which is stored in the specific and azurophilic granules. Activation of PMN results in the rapid release of soluble AGP. PMN AGP exhibits a substantially higher apparent molecular weight than plasma AGP (50 -60 kD vs. 40 -43 kD), owing to the presence of strongly fucosylated and sialylated polylactosamine units on its five Nlinked glycans. PMN AGP is also released in vivo from activated PMN, as appeared from studies using well-characterized myocard slices of patients that had died within 2 weeks after an acute myocardial infarction. AGP was found deposited transiently on damaged cardiomyocytes in areas with infiltrating PMN only. It is interesting that this was inversely related to the deposition of activated complement C3. Strongly fucosylated and sialylated AGP glycoforms have the ability to bind to E-selectin and to inhibit complement activation. We suggest that AGP glycoforms in PMN provide an endogenous feedback-inhibitory response to excessive inflammation. J. Leukoc. Biol. 77: 000 -000; 2005.

Inflammatory reactions contribute to the pathogenesis of cardiovascular conditions such as athero... more Inflammatory reactions contribute to the pathogenesis of cardiovascular conditions such as atherosclerosis and ischemic damage in acute myocardial infarction (AMI). Among the mediators involved in inflammation are secretory phospholipase A2 group II (sPLA2-II) enzymes. Though some cells constitutively express sPLA2-II, the synthesis by cells such as hepatocytes is typical for an acute-phase reactant. Recent literature suggests multiple roles for sPLA2-II in cardiovascular disease. In this review we discuss the role of sPLA2-II in various in vivo and in vitro models of atherosclerosis or AMI, including the therapeutic perspective of sPLA2-II inhibitors. It was concluded that sPLA2-II appears to be an important inflammatory mediator of cardiovascular disease.

Thrombosis and haemostasis, 2002

In a prospective clinical study of 50 patients with Dengue Shock Syndrome (DSS), we investigated ... more In a prospective clinical study of 50 patients with Dengue Shock Syndrome (DSS), we investigated the association of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-1 receptor antagonist (IL-1Ra), and IL-6 with activation markers of coagulation (F1+2 and TATc) and fibrinolysis (t-PA, PAPc, and D-dimer). We found that TNF-alpha, IL-1beta and Il-1Ra, but not IL-6, concentrations were elevated in the circulation during the early stage of infection and at discharge from hospital. TNF-alpha was significantly associated with D-dimer, an activation marker of fibrinolysis (p < 0.003), but not with activation markers of coagulation. IL-1beta was significantly associated with t-PA (p < 0.03). IL-1Ra was significantly associated with F1+2, TATc (p < 0.04 and p < 0.02, respectively), whereas IL-6 was significantly associated with both, activation markers of coagulation (F1+2; p < 0.03) and fibrinolysis (PAPc; p = 0.002). Our data are in line with studies ...

Cardiovascular & hematological disorders drug targets, 2006

Reperfusion of ischemic myocardium after acute myocardial infarction (AMI) induces a local activa... more Reperfusion of ischemic myocardium after acute myocardial infarction (AMI) induces a local activation of inflammatory reactions that results in ischemia/reperfusion (I/R)-injury. I/R-injury contributes considerably to the total cell damage in the heart after AMI. Secretory phospolipase A2-IIA (sPLA2-IIA), C-reactive protein (CRP) and complement are inflammatory mediators that have been demonstrated to play key roles in I/R injury. From studies by us and others a mechanism emerged in which sPLA2-IIA binds to reversibly damaged cardiomyocytes and subsequently induces cell death, partly by potentiating binding of CRP and subsequent complement activation. Next to this, sPLA2-IIA also has a direct toxic effect, independent of CRP or complement. Therefore, these studies indicate a crucial role of inflammatory mediators in ischemia/reperfusion injury. This review will focus on the pathogenic effects of sPLA2-IIA, CRP and complement and on the putative therapeutic effects of inhibitors of t...

Surgery, 2007

Conclusions. CRP and IgM depositions correlated well with local complement activation, which sugg... more Conclusions. CRP and IgM depositions correlated well with local complement activation, which suggests a role of these molecules in complement activation. Furthermore, C1-Inh

The Journal of Thoracic and Cardiovascular Surgery, 1997

Objective: Heparin coating reduces complement activation on the surface of extracorporeal circuit... more Objective: Heparin coating reduces complement activation on the surface of extracorporeal circuits. In this study we investigated its effect on activation of the contact system in 30 patients undergoing coronary artery bypass grafting with the use of a heparin-coated (Duraflo II, Baxter Healthcare Corp., Edwards Division, Santa Ana, Calif.; n = 15) or an uncoated extracorporeal circuit (n = 15). Methods: Plasma markers that reflect activation of contact (kallikrein-Cl-inhibitor complexes), coagulation (prothrombin fragments Fl+2), or fibrinolytic (plasmin-o~2-antiplasmin complexes) systems were determined before and during the operation. The generation of kallikrein-Cl-inhibitor complexes was reduced by 62% (p = 0.06) after the onset of cardiopulmonary bypass and by 43% (p = 0.026) after the cessation of bypass in the group in which a heparin-coated circuit was used compared with the group in which the circuit was uncoated. Generation was reduced by 58% (p = 0.06) when the ratio of kallikrein-Cllinhibitor to prekallikrein after onset of bypass was considered. We detected significant increases in Fl+2 levels in both groups and increases in plasmin-a2-antiplasmin complexes in the heparin-coated group at cessation of bypass, but no intergroup differences were observed. Thus use of heparin-coated extracorporeal circuits during cardiac operations reduces formation of kallikrein-Cl-inhibitor complexes when compared with use of uncoated circuits. The heparin coating is not accompanied by similar reductions in coagulation or fibrinolysis, suggesting that thrombin and plasmin formation during cardiopulmonary bypass occurs mainly indepenl dently of the contact system activation. (J Thorac Cardiovasc Surg 1997; 114:117-22) D uring cardiopulmonary bypass (CPB) the extensive contact between blood and the surface of the extracorporeal circuit (ECC) results in activa-

Journal of Molecular and Cellular Cardiology, 2010

Subsequent to myocardial infarction, cardiomyocytes within the infarcted areas and border zones e... more Subsequent to myocardial infarction, cardiomyocytes within the infarcted areas and border zones expose phosphatidylserine (PS) in the outer plasma membrane leaflet (flip-flop). We showed earlier that in addition to apoptosis, this flip-flop can be reversible in cardiomyocytes. We now investigated a possible role for Rho and downstream effector Rho-associated kinase (ROCK) in the process of (reversible) PS exposure and apoptosis in cardiomyocytes. In rat cardiomyoblasts (H9c2 cells) and isolated adult ventricular rat cardiomyocytes Clostridium difficile Toxin B (TcdB), a Rho GTPase family inhibitor, C3 transferase (C3), a Rho (A,B,C) inhibitor and the ROCK inhibitors Y27632 and H1152 were used to inhibit Rho-ROCK signaling. PS exposure was assessed via flow cytometry and fluorescent digital imaging microscopy using annexin V. Akt expression and phosphorylation were analyzed via Western blot, and Akt activity was inhibited by wortmannin. The cellular concentration activated caspase 3 was determined as a measure of apoptosis, and flippase activity was assessed via flow cytometry using NBD-labeled PS. TcdB, C3, Y27632 and H1152 all significantly increased PS exposure. TcdB, Y27632 and H1152 all significantly inhibited phosphorylation of the anti-apoptotic protein Akt and Akt inhibition by wortmannin lead to increased PS exposure. However, only TcdB and C3, but not ROCK-or Akt inhibition led to caspase 3 activation and thus apoptosis. Notably, pancaspase inhibitor zVAD only partially inhibited TcdB-induced PS exposure indicating the existence of apoptotic and non-apoptotic PS exposure. The induced PS exposure coincided with decreased flippase activity as measured with NBD-labeled PS flip-flop. In this study, we show a regulatory role for a novel signaling route, Rho-ROCK-flippase signaling, in maintaining asymmetrical membrane phospholipid distribution in cardiomyocytes.

The Journal of Infectious Diseases, 1997

Escherichia coli were pretreated with either a 55-kDa tumor necrosis factor (TNF) receptor -IgG f... more Escherichia coli were pretreated with either a 55-kDa tumor necrosis factor (TNF) receptor -IgG fusion protein (TNFR55:IgG) (n Å 4, 4.6 mg/kg) or placebo (n Å 4). Neutralization of TNF activity in TNFR55:IgGtreated animals was associated with a complete prevention of mortality and a strong attenuation of coagulation activation as reflected by the plasma concentrations of thrombin -antithrombin III complexes (P õ .05). Activation of fibrinolysis was not influenced by TNFR55:IgG (plasma tissuetype plasminogen activator and plasmin -a 2 -antiplasmin complexes), whereas TNFR55:IgG did inhibit the release of plasminogen activator inhibitor type I (P õ .05). Furthermore, TNFR55:IgG inhibited neutrophil degranulation (plasma levels of elastase -a 1 -antitrypsin complexes, P õ .05) and modestly reduced release of secretory phospholipase A 2 . These data suggest that endogenous TNF contributes to activation of coagulation, but not to stimulation of fibrinolysis, during severe bacteremia.

The Journal of Infectious Diseases, 2007

In spite of antibiotic treatment, pneumococcal meningitis continues to be associated with signifi... more In spite of antibiotic treatment, pneumococcal meningitis continues to be associated with significant morbidity and mortality. The complement system is a key component of innate immunity against invading pathogens. However, activation of complement is also involved in tissue damage, and complement inhibition by C1 inhibitor (C1-inh) is beneficial in animal models of endotoxemia and sepsis. In the present study, we demonstrate classical pathway complement activation during pneumococcal meningitis in rats. We also evaluate the effect of C1-inh treatment on clinical illness, bacterial clearance, and inflammatory responses in rats and mice with pneumococcal meningitis. C1-inh treatment was associated with reduced clinical illness, a lesspronounced inflammatory infiltrate around the meninges, and lower brain levels of proinflammatory cytokines and chemokines. C1-inh treatment increased bacterial clearance, possibly through an up-regulation of CR3. Hence, C1-inh may be a useful agent in the treatment of pneumococcal meningitis.

Journal of Biological Chemistry, 2003

C1-inhibitor (C1-Inh) is a serine protease inhibitor (serpin) with a unique, non-conserved N-term... more C1-inhibitor (C1-Inh) is a serine protease inhibitor (serpin) with a unique, non-conserved N-terminal domain of unknown function. Genetic deficiency of C1-Inh causes hereditary angioedema. A novel type of mutation (Delta 3) in exon 3 of the C1-Inh gene, resulting in deletion of Asp62-Thr116 in this unique domain, was encountered in a hereditary angioedema pedigree. Because the domain is supposedly not essential for inhibitory activity, the unexpected loss-of-function of this deletion mutant was further investigated. The Delta 3 mutant and three additional mutants starting at Pro76, Gly98, and Ser115, lacking increasing parts of the N-terminal domain, were produced recombinantly. C1-Inh76 and C1-Inh98 retained normal conformation and interaction kinetics with target proteases. In contrast, C1-Inh115 and Delta 3, which both lack the connection between the serpin and the non-serpin domain via two disulfide bridges, were completely non-functional because of a complex-like and multimeric conformation, as demonstrated by several criteria. The Delta 3 mutant also circulated in multimeric form in plasma from affected family members. The C1-Inh mutant reported here is unique in that deletion of an entire amino acid stretch from a domain not shared by other serpins leads to a loss-of-function. The deletion in the unique N-terminal domain results in a &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;multimerization phenotype&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; of C1-Inh, because of diminished stability of the central beta-sheet. This phenotype, as well as the location of the disulfide bridges between the serpin and the non-serpin domain of C1-Inh, suggests that the function of the N-terminal region may be similar to one of the effects of heparin in antithrombin III, maintenance of the metastable serpin conformation.

Journal of Allergy and Clinical Immunology, 2004

Hereditary angioedema (HAE), a rare but life-threatening condition, manifests as acute attacks of... more Hereditary angioedema (HAE), a rare but life-threatening condition, manifests as acute attacks of facial, laryngeal, genital, or peripheral swelling or abdominal pain secondary to intra-abdominal edema. Resulting from mutations affecting C1 esterase inhibitor (C1-INH), inhibitor of the first complement system component, attacks are not histamine-mediated and do not respond to antihistamines or corticosteroids. Low awareness and resemblance to other disorders often delay diagnosis; despite availability of C1-INH replacement in some countries, no approved, safe acute attack therapy exists in the United States. The biennial C1 Esterase Inhibitor Deficiency Workshops resulted from a European initiative for better knowledge and treatment of HAE and related diseases. This supplement contains work presented at the third workshop and expanded content toward a definitive picture of angioedema in the absence of allergy. Most notably, it includes cumulative genetic investigations; multinational laboratory diagnosis recommendations; current pathogenesis hypotheses; suggested prophylaxis and acute attack treatment, including home treatment; future treatment options; and analysis of patient subpopulations, including pediatric patients and patients whose angioedema worsened during pregnancy or hormone administration. Causes and management of acquired angioedema and a new type of angioedema with normal C1-INH are also discussed. Collaborative patient and physician efforts, crucial in rare diseases, are emphasized. This supplement seeks to raise awareness and aid diagnosis of HAE, optimize treatment for all patients, and provide a platform for further research in this rare, partially understood disorder. (J Allergy Clin Immunol 2004;114:S51-131.)

Journal of Allergy and Clinical Immunology, 1991

Fifty-six patients affected with hereditary angioedema have been followed during long-term prophy... more Fifty-six patients affected with hereditary angioedema have been followed during long-term prophylaxis with attenuated androgens. The treatment was started in patients who had one or more severe attacks per month. In 24 patients, the therapy lasted for more than 5 years. The minimal effective dose usually did not exceed 2 mg/day of stanozolol or 200 mg/day of danazol. Only in two patients were these doses not sufficient to achieve the complete disappearance of symptoms. Irregular menstruation, but rarely amenorrhea, was the only significant side effect. One patient had to stop the therapy because of laboratory signs of hepatic cell necrosis. In one patient, danazol was administered during the last 8 weeks of pregnancy without side effects for the mother but with transient signs of virilization for the female baby. To find a biochemical marker for the minimal effective dose of androgen derivatives, we measured the plasma levels of C1 C1 INH complexes at different doses of stanozolol in four patients with hereditary angioedema. We found that these complexes, elevated before treatment, promptly reverted to normal values during androgen therapy and remained normal with any reduction of the dose of the drug as long as the patient remained symptom free. Therefore, the measurement of C1 C1 INH complexes appears to reflect the activity of the disease and not the amount of androgen that is administered.

International Archives of Allergy and Immunology, 1996

We have investigated whether IL-8 is present in airway secretions from patients with asthma and c... more We have investigated whether IL-8 is present in airway secretions from patients with asthma and chronic obstructive pulmonary disease (COPD) to obtain information on its possible role in airway inflammation in obstructive airways disease. In the bronchoalveolar lavage fluid (BALF ...

Immunobiology, 2002

C1-Inh is a serpin that inhibits serine proteases from the complement and the coagulation pathway... more C1-Inh is a serpin that inhibits serine proteases from the complement and the coagulation pathway. C1-Inh consists of a serpin domain and a unique N-terminal domain and is heavily glycosylated. Non-functional mutants of C1-Inh can give insight into the inhibitory mechanism of C1-Inh. This review describes a novel 3D model of C1-Inh, based on a newly developed homology modelling method. This model gives insight into a possible potentiation mechanism of C1-Inh and based on this model the essential residues for efficient inhibition by C1-Inh are discussed.

Gastroenterology, 2000

activity was clearly dose-dependent. We did not detect any change of ODC activity among GRP when ... more activity was clearly dose-dependent. We did not detect any change of ODC activity among GRP when colonioc mucosae were examined. To investigate whether the enhancing effect of GLP-2 is direct on epithelial cells, IEC-6 cells were stimulated with each GRP. GLP-2 increased ODC activity also in IEC-6 cells, suggesting that, at least in part, GLP-2 effects may be direct. In contrast to the case in vivo, GLI also exhibited induction of ODC activity. CONCLUSIONS: Only GLP-2 in EG family increased ODC activity in both in vivo and in vitro system. Therefore, a possible trophic effect may be selective to GLP-2 and not to the others of GRP.

European Journal of Clinical Investigation, 2010

Clusterin (Apolipoprotein J), a plasma protein with cytoprotective and complement-inhibiting acti... more Clusterin (Apolipoprotein J), a plasma protein with cytoprotective and complement-inhibiting activities, localizes in the infarcted heart during myocardial infarction (MI). Recently, we have shown a protective effect of exogenous clusterin in vitro on ischaemically challenged cardiomyocytes independent of complement. We therefore hypothesized that intravenous clusterin administration would reduce myocardial infarction damage. Wistar rats undergoing experimental MI, induced by 40 min ligation of a coronary vessel, were treated with either clusterin (n=15) or vehicle (n=13) intravenously, for 3 days post-MI. After 4 weeks, hearts were analysed. The putative role of megalin, a clusterin receptor, was also studied. Administration of human clusterin significantly reduced both infarct size (with 75 ± 5%) and death of animals (23% vehicle group vs. 0% clusterin group). Importantly, histochemical analysis showed no signs of impaired wound healing in the clusterin group. In addition, significantly increased numbers of macrophages were found in the clusterin group. We also found that the clusterin receptor megalin was present on cardiomyocytes in vitro which, however, was not influenced by ischaemia. Human clusterin co-localized with this receptor in vitro, but not in the human heart. In addition, using a megalin inhibitor, we found that clusterin did not exert its protective effect on cardiomyocytes through megalin. Our results thus show that clusterin has a protective effect on cardiomyocytes after acute myocardial infarction in vivo, independent of its receptor megalin. This indicates that clusterin, or a clusterin derivate, is a potential therapeutic agent in the treatment of MI.

European Journal of Cardio-Thoracic Surgery, 1997

This study was carried out to: (a) compare complement and granulocyte activation during cardiac o... more This study was carried out to: (a) compare complement and granulocyte activation during cardiac operations in patients operated with cardiopulmonary bypass coated with heparin by the Duraflo II method, with activation in patients operated with uncoated circuits; and (b) relate complement, and granulocyte activation to selected adverse effects. In a multicentre study among Rikshospitalet, Ullevaal Hospital in Norway and Uppsala University Hospital in Sweden, plasma concentrations of the complement activation products C4b/iC4b/C4c (C4bc), C3b/iC3b/C3c (C3bc), the terminal SC5b-9 complement complex (TCC), and the granulocyte proteins myeloperoxidase and lactoferrin were assessed in two groups of patients undergoing aortocoronary bypass. Seventy-six patients underwent surgery operated with circuits coated by the Duraflo II heparin coating and 75 uncoated circuits. The same amount of systemic heparin was administered to all patients. In both groups a significant increase in C4bc was first seen by the end of operation, from 86.7 +/- 12.5 to 273.0 +/- 277.4 nM in controls and from 86.9 +/- 18.5 to 320.2 +/- 190.5 nM in the control group, confirming previous documentation that the classical pathway is not activated during CPB, but as a consequence of protamin administration. The formation of C4bc did not differ significantly between the two groups. In the uncoated group the C3bc concentration increased from 124.0 +/- 15.3 to a maximum of 1176.1 +/- 64.7 nM (P < 0.01) and in the coated group it increased from 129.8 +/- 16.1 to a maximum of 1019.4 +/- 54.9 nM (P < 0.01) during CPB. Summary values but not peak values differed significantly between the groups. In the uncoated group the TCC concentration increased from 0.52 +/- 0.03 to a maximum value of 8.09 +/- 0.57 AU/ml (P < 0.01) while in the coated group the TCC concentration increased from a baseline of 0.53 +/- 0.03 to a peak value of 5.2 +/- 0.24 AU/ml (P <0.01). The difference between the peak values was statistically significant (P = 0.00002). In both groups a significant increase in myeloperoxidase and lactoferrin release was observed by the end of operation. There was no difference in myeloperoxidase or lactoferrin release between the two groups. TCC levels were compared to the occurrence of perioperative infarction, development of lung or renal failure, postoperative bleeding, time on ventilator and days in hospital. Three patients developed perioperative infarction; the peak levels of TCC were significantly higher in these patients than in the 148 patients that did not develop infarction. The reduction in TCC formation in the heparin-coated group was not associated with differences in any of the other clinical parameters. Few adverse effects occurred in the study. The peak values of C3bc were higher in the patients needing inotropic support that in those who did not, the relevance of this finding remains uncertain. It is concluded that the Duraflo II heparin coating reduces complement activation, particularly TCC formation, during CPB, but not the release of specific neutrophil granule enzymes. No certain correlation was established between complement and granulocyte activation and clinical outcome.

Cytokine, 1997

Intravenous injection of sublethal or lethal doses of Escherichia coli in baboons resulted in inc... more Intravenous injection of sublethal or lethal doses of Escherichia coli in baboons resulted in increased serum levels of the matrix metalloprotease gelatinase B and the chemokine monocyte chemotactic protein 2 (MCP-2). In both animal models, gelatinase B appeared faster than MCP-2. After sublethal challenge, serum levels of gelatinase B and MCP-2 were found to be correlated, reaching peak levels between 2 and 4 h after bacterial challenge. After lethal challenge, however, MCP-2 tended to increase until 10 h. The kinetics of appearance suggest induction of release of gelatinase B and de novo synthesis and secretion of MCP-2, both by endotoxin.