Increase of Plasminogen Activator Inhibitor Levels Predicts Outcome of Leukocytopenic Patients with Sepsis

Variables of the fibrinolytic system were prospectively studied in patients with haematologic malignancies in chemotherapy-induced leukocytopenia at onset and during the course of septicemia to evaluate their prognostic value. This group of patients was chosen because of their high risk of developing severe septic complications, thus allowing serial prospective testing of fibrinolytic variables prior to and during evolving sepsis or septic shock. 62 patients with febrile infectious events were accrued to the study. Of these, 13 patients progressed to severe sepsis and an additional 13 patients to septic shock as defined according to standard diagnostic criteria. At onset of fever, plasminogen activator inhibitor (PAI) activity and PAI-1 antigen levels increased from normal baseline levels and were significantly higher in the group of patients who developed septic shock compared to those with severe sepsis (medians: 10.6 versus 1.3 U/ml, p = 0.0001; 50.0 versus 5.0 ng/ml, p = 0.0002). The increase in PAI activity and antigen in septic shock was accompanied by an increase in tissue-type plasminogen activator antigen and total fibrin(ogen) degradation products and a decrease in alpha2-antiplasmin activity (p < 0.006). In contrast, in the group of patients that developed severe sepsis the variables of the fibrinolytic system remained unchanged at onset of fever. These differences between septic shock apd severe sepsis were sustained throughout the septic episode for all variables (p <0.0001). PAI activity of >5 U/ml at onset of fever predicted a lethal outcome with a sensitivity of 92% and a specificity of 100%. Thus, septic shock in leukocytopenia is associated with significant activation of the fibrinolytic system presumably as a response of the vascular endothelium to inflammatory injury. Furthermore, PAI activity measurements are sensitive markers of an unfavourable prognosis.

Induction therapy of AML with ara-C plus daunorubicin versus ara-C plus gemtuzumab ozogamicin: a randomized phase II trial in elderly patients

BACKGROUND

Chemotherapy for elderly patients with acute myeloid leukemia (AML) results in a median overall survival (OS) of ≤ 1 year. Elderly patients often present with cardiac comorbidity. Gemtuzumab ozogamicin (GO) is active in elderly (≥ 60 years) patients with relapsed AML with low cardiac toxicity.

PATIENTS AND METHODS

This randomized phase II study compared a standard combination of ara-C and daunorubicin (DNR; 7+3) versus ara-C plus gemtuzumab ozogamicin (7+GO) as the first course of induction therapy. Primary objectives were comparison of blast clearance on day 16, event-free survival (EFS), and remission duration. OS, complete remission (CR), and tolerability were secondary objectives.

RESULTS

One hundred and nineteen patients with de novo AML, treatment-related AML, AML with a history of myelodysplastic syndrome (MDS), or high-risk MDS entered the study. Median age of 115 patients (intent-to-treat population) was 69 years. Protocol outlined a second course 7+3 for patients without blast clearance and two courses of high-dose ara-C consolidation upon CR. Both treatments were equally effective in blast clearance, CR, EFS, remission duration, or OS (median: 7+3, 9 months; 7+GO, 10 months). Induction death rate was higher in the GO group due to veno-occlusive disease.

CONCLUSION

The study did not show significant superiority of 7+GO over standard 7+3.

Thalidomide for the Treatment of Acute Myeloid Leukemia

In analogy to solid neoplasms, accumulating data suggest the requirement of angiogenesis also for the development and progression of hematopoietic malignancies including acute myeloid leukemia (AML). Inhibition of increased microvessel density in bone marrow (BM) might be a promising target for pharmacological interventions aimed at reducing disease activity. Among the putative inhibitors of angiogenesis, thalidomide has demonstrated a considerable efficacy in myelodysplastic syndromes (MDS) and AML with overall response rates up to 56% and 25%, respectively. Responders experienced hematologic improvements with increased hemoglobin and platelet counts resulting in temporary transfusion independence. In AML, partial responses--defined as reduction of the leukemic blast cell infiltration of at least 50% in BM--occurred in four of 20 patients after one month of thalidomide administration in a previous phase I/II study. Additionally, we observed a long-term response in one AML patient of more than 20 months, meanwhile fulfilling the criteria of complete remission. The decrease in leukemic blast infiltration in BM of responders was accompanied by a significant reduction of the microvessel density. Overall adverse events caused by the drug consisted mainly of fatigue, constipation, skin rash and polyneuropathy with a tolerable dose of 200-400 mg p.o. per day. In conclusion, thalidomide as a single agent has significant anti-leukemic activity with some evidence for anti-angiogenic effects in BM, although the precise mechanism of action remains to be elucidated.

Amsacrine containing induction therapy in elderly AML patients: Comparison to standard induction regimens in a matched-pair analysis

Many elderly patients with newly diagnosed acute myeloid leukemia (AML) present with cardiac comorbidity precluding the use of anthracycline containing chemotherapy regimens. Amsacrine, a topoisomerase II inhibitor, has been proposed as possible alternative to anthracyclines. Here, we report about the combination of amsacrine (210 mg/m(2)), in replacement for daunorubicin (DNR), with standard dose cytarabine and thioguanine (TAA) to elderly patients (>or=60 years of age) with impaired cardiac function. The outcome of 16 patients with a median age of 66 years treated between 1997 and 2003 was compared with standard treatment regimens of the AMLCG study group in a matched-pair analysis. There were no statistically significant differences in response rate, relapse free survival or overall survival between TAA treated patients or standard therapy. In conclusion, replacing anthracyclines with amsacrine for induction therapy of AML patients with significant cardiac comorbidities represents a treatment option without compromising the potential curability of the disease.

Chemotherapy in metastatic malignant triton tumor: report on two cases

Malignant triton tumor (MTT) is a rare, highly malignant nerve sheath tumor with rhabdomyoblastic differentiation. Initial debulking surgery followed by adjuvant therapy is the current treatment of choice, but has very limited efficacy when optimal cytoreduction is not achieved by surgical procedure. Neoadjuvant therapy for MTT, to potentially facilitate subsequent surgery, eradicate micrometastatic lesions and, therefore, improve the therapeutical outcome, has never before been presented in literature. Here, we report on the multimodal management of two cases of advanced and metastatic MTT. Treatment modalities involved neoadjuvant and adjuvant chemotherapy, surgical resection, and radiation. In both cases, integrated Positron Emission Tomography/Computed Tomography (PET/CT) emerged as an important diagnostic tool for the reliable assessment of MTT response and metabolic remission.

Circulating angiopoietin-2 is a strong prognostic factor in acute myeloid leukemia

Angiogenesis plays an important role in solid tumors and hematologic malignancies. The angiopoietins act as essential regulators in this process. We investigated the impact of circulating angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2) and soluble Tie2 (sTie2) on overall survival in patients with acute myeloid leukemia (AML). Ang-1, Ang-2 and sTie2 were measured in plasma samples from 68 AML patients and 11 controls using enzyme-linked immunosorbent assay. Circulating levels of Ang-2 and sTie2 (median (range): 1098.0 (361.4-4147.6) pg/ml and 3.40 (1.21-10.00) ng/ml, respectively) were significantly elevated in AML patients as compared to controls (307.9 (199.7-1225.0) pg/ml and 2.88 (1.71-3.29) ng/ml; P<0.001 and P=0.014). In a univariate Cox proportional hazards model, higher levels of Ang-2 and sTie2 were predictive of poor survival. In multivariate analyses, Ang-2 and cytogenetics proved to be independent prognostic factors, with a relative risk of 4.07 (95% confidence interval (CI) 1.88-8.81) and 2.70 (95% CI 1.25-5.81), respectively. The 3-year survival rate for AML patients with Ang-2 levels>/=1495.6 pg/ml was only 14.7% compared to 64.7% for those with Ang-2 levels<1495.6 pg/ml. These data provide evidence that circulating Ang-2 represents an independent prognostic factor in AML and may be used as a prognostic tool in the risk-adapted management of AML.

Correlation of neuropilin-1 overexpression to survival in acute myeloid leukemia

Neuropilin-1 (NRP-1), a vascular endothelial growth factors and semaphorin receptor functioning as mediator of angiogenesis and neuronal guidance, is expressed by various solid tumors. The importance of NRP-1 in hematological malignancies such as acute myeloid leukemia (AML) remains to be elucidated. Therefore, we determined NRP-1 expression by immunohistochemical analysis of bone marrow biopsies of patients with newly diagnosed, untreated AML. The expression of NRP-1 was significantly increased in AML patients (n = 76; median 12.9 arbitrary units (a.u.)) as compared with controls (n = 38; median 2.75 a.u.). Survival was significantly poorer in patients with high (> median) versus low (< or = median) NRP-1 expression levels with 5-year overall survival rates of 16.9 versus 49.6% (P = 0.050). In conclusion, our data provide evidence of increased NRP-1 expression in AML with significant correlation to survival. Thus, NRP-1 might constitute a promising target for antileukemic and antiangiogenic treatment strategies in AML.

Acquired haemophilia in a patient with gram-negative urosepsis and bladder cancer

We here report a patient who developed a high titer antibody to factor VIII (FVIII) during gram-negative urosepsis caused by enterobacter cloacae after complete resection of rectal cancer. The patient initially presented with a life threatening spontaneous hematothorax and multiple large haematomas. Coagulation studies revealed a severe FVIII deficiency <1% with a high FVIII antibody titer of 64 BU. The bleeding responded rapidly to infusions of recombinant factor VIIa. After achievement of a partial remission (FVIII activity 28%) by combined immunosuppressive therapy (prednisone, cyclophosphamide, plasmapheresis and immunoadsorption), subsequently, two relapses occurred following steroid tapering. Resumption of prednisone and cyclophosphamide treatment combined with immunoadsorption induced a second and third remission, respectively. After resection of a papillary carcinoma of the bladder 6 months later and continuous immunosuppressive therapy with cyclophosphamide, FVIII levels remained stable within normal ranges. This clinical course suggests that the cause of inhibitor formation against FVIII resulting in severe acquired haemophilia was multifactorial and was initiated by the gram-negative urosepsis and probably by the underlying malignancies.

Stable remission after administration of rituximab in a patient with primary hepatic marginal zone B-cell lymphoma

We describe a case of primary hepatic marginal zone B-cell lymphoma in a 36-year-old Caucasian male with a history of chronic hepatitis B infection. Immunohistochemically, extensive infiltration by a CD20-positive, CD5- negative and CD10-negative lymphoid cell population displaying a follicular arrangement was detected. Molecular analysis of immunoglobulin heavy chain gene rearrangements confirmed the clonal expansion of lymphoma cells. Fourteen months after surgical treatment, the tumour recurred in close proximity to the liver hilus, hampering further surgery. Therefore, we implemented a therapy using the monoclonal anti-CD20-antibody rituximab in a dose of 375 mg/m(2), administered four times once a week. Six, 10, 18, and 26 months later the recurrent lymphoma could no longer be detected as shown by abdominal ultrasonography and CT. This case report demonstrates the difficulties of treating this extremely rare liver disease and shows its response to rituximab therapy.

Neoplastic Heart Disease - The Muenster Experience With 108 Patients

BACKGROUND

Tumours of the heart are rare. Different histological subtypes are known. The most common tumour entity is benign cardiac myxoma. Malignant heart tumours are less common. Tumours originating in other organs such as the kidney may also affect the heart by tumour progression via the inferior caval vein. A large experience with surgical treatment of different types of heart tumours is presented.

METHODS

Between January 1989 and April 2004, 108 patients with a heart tumour were included in a database. All patients underwent radical surgical resection, except for 2 patients who had malignant lymphoma of the heart.

RESULTS

Histological findings included 78 myxomas (72.2 %), and 6 other benign cardiac tumours in 5.6 % of the patients. Primary malignant heart tumours were seen in 10 (9.2 %) and renal cell carcinoma with cardiac involvement in 6 (5.6 %) patients. Eight patients presented with tumour metastases inside the heart (7.4 %). Mean overall survival was 12.7 years for myxoma patients and 5.6 years for patients with other benign heart tumours. Patients with primary malignant heart tumours survived 5.5 years on average.

CONCLUSIONS

Heart tumours are rare, but usually life-threatening. Radical surgical resection is the therapy of choice and may offer excellent long-term survival, even in cases with malignant heart tumours.

Matrix metalloproteinase/integrin interactions as target for anti-angiogenic treatment strategies

Modulation of the balance between pro- and antiangiogenic factors holds great promise for the treatment of a broad spectrum of human disease ranging from ischemic heart disease to cancer. This requires both the identification of angiogenic regulators and their efficient delivery to target organs. Here, we demonstrate the use of a noncatalytic fragment of matrix metalloproteinase 2 (termed PEX) delivered by lentiviral vectors in different angiogenesis models. Transduction of human endothelial cells with PEX virus suppressed endothelial invasion and formation of capillary-like structures without affecting chemotaxis in vitro. Lentiviral delivery of PEX blocked basic fibroblast growth factor-induced matrix metalloproteinase 2 activation and angiogenesis on chicken chorioallantoic membranes. PEX expression also inhibited tumor-induced angiogenesis and tumor growth in a nude mouse model. Thus, our study shows that lentiviral vectors can deliver sufficient quantities of antiangiogenic substances to achieve therapeutic effects in vivo.

Overexpression of vascular endothelial growth factor (VEGF) and its cellular receptor KDR (VEGFR-2) in the bone marrow of patients with acute myeloid leukemia

Vascular endothelial growth factor (VEGF) and its cellular receptor VEGFR-2 have been implicated as the main endothelial pathway required for tumor neovascularization. However, the importance of the VEGF/VEGFR-2 system for angiogenesis in hematologic malignancies such as AML remains to be elucidated. In 32 patients with newly diagnosed untreated AML, we observed by immunohistochemical analysis of bone marrow biopsies significantly higher levels of VEGF and VEGFR-2 expression than in 10 control patients (P <0.001). In contrast, VEGFR-1 staining levels in AML patients were in the same range as in the controls. Expression of VEGF and VEGFR-2 was significantly higher in patients with a high degree of microvessel density compared to those with a low degree (VEGF: P =0.024; VEGFR-2: P =0.040) and correlated well with bone marrow microvessel density (r(s)=0.566 and 0.609, respectively; P <0.001). Furthermore, in patients who achieved a complete remission following induction chemotherapy VEGFR-2 staining levels decreased into the normal range. In conclusion, our results provide evidence for increased expression of VEGF/VEGFR-2 of leukemic blasts and correlation with angiogenesis in the bone marrow of AML patients. Thus, VEGF/VEGFR-2 might constitute promising targets for antiangiogenic and antileukemic treatment strategies in AML.

[Primary Burkitt lymphoma of the heart--diagnosis and therapy]

An 85-year-old patient suffered from progressive deterioration (NYHA III) for several months. Cardiac disease was suspected. Echocardiography as well as a CT scan of the heart revealed a heart tumor to be the cause. Tumor staging was negative. After transvenous biopsy, the diagnosis of a Burkitt lymphoma could be established. Due to the advanced age of the patient, the intended surgical therapy was turned down and the patient was treated with 6 courses of a potentially therapeutic chemotherapy (CHOP scheme), which was well tolerated by the patient. The following CT scan showed a complete remission of the tumor. Six months after chemotherapy the patient is in NYHA stage I.

[Angiogenesis in patients with hematologic malignancies]

Angiogenesis in Patients with Hematologic Malignancies The importance of angiogenesis for the progressive growth and viability of solid tumors is well established. Emerging data suggest an involvement of angiogenesis in the pathophysiology of hematologic malignancies as well. Recently, we and others have reported increased angiogenesis in the bone marrow of patients with acute myeloid leukemia (AML) and normalization of bone marrow microvessel density when patients achieved a complete remission (CR) after induction chemotherapy. Tumor angiogenesis depends on the expression of specific mediators that initiate a cascade of events leading to the formation of new microvessels. Among these, VEGF (vascular endothelial growth factor), FGF (fibroblast growth factor) and angiopoietins play a pivotal role in the induction of neovascularization in solid tumors. These cytokines stimulate migration and proliferation of endothelial cells and induce angiogenesis in vivo. Recent data suggest an important role for these mediators in hematologic malignancies as well. Isolated AML blasts overexpress VEGF and VEGF receptor 2. Thus, the VEGF/VEGFR-2 pathway can promote the growth of leukemic blasts in an autocrine and paracrine manner. Therefore, neovascularization and angiogenic mediators/receptors may be promising targets for anti-angiogenic and anti-leukemic treatment strategies. The immunomodulatory drug thalidomide inhibits angiogenesis in animal models. Moreover, it has significant activity in refractory multiple myeloma. In a current phase II study for patients with primary refractory or relapsed multiple myeloma using a combination of thalidomide with hyperfractionated cyclophosphamide and dexamethasone (Hyper-CDT), we observed a partial remission in 12 of 14 evaluable patients (86%). Thus, this combination seems to be very potent. Furthermore, we evaluated the safety and efficacy of thalidomide in patients with AML not qualifying for intensive cytotoxic chemotherapy. 20 patients aged 58-85 (median 69) years were recruited to this phase I/II study and were treated with a dose of 200-400 mg per os daily for a duration of 1-40 (median 6) weeks, dependent on the individual tolerability of the drug. In 4 patients we observed a partial response (PR - defined as more than 50% reduction in leukemic blast infiltration in the bone marrow). This was accompanied by an increase in platelet counts and hemoglobin values. One additional patient showed a significant improvement of peripheral blood counts without fulfilling the criteria of a PR. In parallel, we observed a significant decrease in microvessel density in these 5 patients during treatment with thalidomide. In conclusion, thalidomide seems to have anti-angiogenic as well as anti-leukemic activity in AML. The VEGF/VEGFR-2 pathway seems to play an important role in AML. Therefore, receptor tyrosine kinase inhibitors like SU5416 or SU6668 are currently evaluated in the context of phase II studies in AML. We could recently induce a stable remission in a patient with second relapse of her AML refractory towards chemotherapy by administration of SU5416 (compassionate use), a tyrosine kinase inhibitor of VEGFR-2 and ckit. Current and future studies will clarify the role of anti-angiogenic treatment strategies in AML and other hematologic malignancies.

Stable remission after administration of the receptor tyrosine kinase inhibitor SU5416 in a patient with refractory acute myeloid leukemia

The small molecule receptor tyrosine kinase (RTK) inhibitor SU5416 targets the vascular endothelial growth factor receptor 2 and the stem cell factor receptor c-kit. Herein is described the successful treatment of a 65-year-old woman with SU5416, in second relapse of acute myeloid leukemia (AML) and refractory toward standard chemotherapy regimens. After 12 weeks of treatment with SU5416, the blast cell counts (blood and bone marrow) decreased to undetectable levels and the peripheral blood cell counts normalized with the exception of the platelet count (50-80 x 10(9)/L [50-80 x 10(3)/microL]). The duration of the remission is longer than 4 months during maintenance therapy with SU5416. Microvessel density in the patient's bone marrow dropped from 33.4 to 12.3 microvessels/x500-field 8 weeks after SU5416 administration and remains in the normal range. This is the first report of a stable remission achieved after administration of the RTK inhibitor SU5416 in a patient with AML relapse.

Prognostic value of protein C concentrations in neutropenic patients at high risk of severe septic complications

OBJECTIVE

To assess the prognostic value of protein C, endogenous activated protein C, and D-dimer concentrations in patients at high risk of developing severe septic complications secondary to cytostatic chemotherapy.

DESIGN

Prospective, comparative, single-center study.

SETTING

Specialized ward for treating patients with acute leukemia and associated intensive care unit at a university hospital.

SUBJECTS

Twenty-six consecutive patients who developed either severe sepsis (n = 13) or septic shock (n = 13) during chemotherapy-induced neutropenia (leukocytes <1,000/microL).

INTERVENTION

None, other than standard care.

MEASUREMENTS AND MAIN RESULTS

Baseline blood samples were obtained from 97 adult patients treated with intensive cytostatic chemotherapy. Serial blood sampling was performed in 62 of 97 patients who developed fever (>38.3 degrees C). Thirteen patients progressed to severe sepsis and 13 patients to septic shock. Protein C, endogenous activated protein C, and D-dimer were measured in these 26 patients. At fever onset, protein C concentrations decreased from normal baseline concentrations and were significantly lower in the group of patients who progressed to septic shock compared with those who developed severe sepsis (medians for protein C activity: 23.1% vs. 69.5%; p = .0003). The median elapsed time between detection of fever and the diagnosis of severe sepsis or septic shock was 16 hrs and 12 hrs, respectively. All septic shock patients died, whereas patients who progressed only to severe sepsis survived.

CONCLUSIONS

Septic shock in neutropenic patients is associated with increased protein C consumption. The data demonstrate that the coagulation cascade is activated and produces a hypercoagulable state before the onset of clinical symptoms of severe sepsis and septic shock. Low protein C concentrations at the onset of fever and before the onset of clinical symptoms of severe sepsis or septic shock may have prognostic value in predicting an unfavorable outcome. Protein C measurements may help identify patients at risk in an early phase of neutropenic sepsis. It is also attractive to speculate that because low protein C concentrations were seen in these patients, protein C replacement may be beneficial in sepsis.

Increased angiogenesis in the bone marrow of patients with acute myeloid leukemia

The importance of angiogenesis for the progressive growth and viability of solid tumors is well established. In contrast, only few data are available for hematologic neoplasms. To investigate the role of angiogenesis in acute myeloid leukemia (AML), bone marrow biopsies from 62 adults with newly diagnosed, untreated AML (day 0) were evaluated. Further studies were done after the completion of remission induction chemotherapy (day 16 of induction chemotherapy, n = 21; complete remission, n = 20). Microvessels were scored in at least 3 areas (x500 field, 0.126 mm(2)) of the highest microvessel density in representative sections of each bone marrow specimen using immunohistochemistry for von Willebrand factor and thrombomodulin. Microvessel counts were significantly higher in patients with AML (n = 62) compared with control patients (n = 22): median (interquartile range) 24.0 (21.0-27.8)/x500 field vs 11.2 (10. 0-12.0)/x500 field, respectively (P <.001). On day 16 of induction chemotherapy, microvessel density was reduced by 60% (44-66) (P <. 001) in hypoplastic marrows without residual blasts, in contrast to only 17% (0-37) reduction in hypoplastic marrows with >/= 5% residual blasts (P <.001 for the difference between both groups). Bone marrow biopsies taken at the time of complete remission displayed a microvessel density in the same range as the controls. In conclusion, there is evidence of increased microvessel density in the bone marrow of patients with AML, which supports the hypothesis of an important role of angiogenesis in AML. Furthermore, these findings suggest that antiangiogenic therapy might constitute a novel strategy for the treatment of AML. (Blood. 2000;95:2637-2644)

Vascular endothelial growth factor and interleukin-6 in paracrine tumor-stromal cell interactions in multiple myeloma

Vascular endothelial growth factor (VEGF), a multifunctional cytokine, potently stimulates angiogenesis including tumor neovascularization. Although well established in solid tumors, the role of VEGF in bone marrow neoangiogenesis and paracrine tumor-stromal cell interactions in lymphohematopoietic malignancies has not been fully elucidated. In multiple myeloma (MM), marrow neovascularization parallels disease progression. This parallel prompted us to investigate the expression and secretion of VEGF by myeloma cells and its potential effects in myeloma-marrow stroma interactions. The biologically active splice variants VEGF165 and VEGF121 were expressed and secreted by myeloma cell lines and plasma cells isolated from the marrow of patients with MM. As shown by immunocytochemistry or RT-PCR, myeloma cells did not express or weakly expressed the VEGF receptors FLT-1 and FLK-1/KDR, indicating that autocrine stimulation is unlikely. In contrast, FLK-1/KDR was abundantly expressed by marrow stromal cells. Therefore, we studied the effects of VEGF on marrow stroma, focusing on the secretion of interleukin-6 (IL-6), a potent growth factor for myeloma cells and an inhibitor of plasma cell apoptosis. Exposure of stromal and microvascular endothelial cells to recombinant human (rh) VEGF165 or VEGF121 induced a time- and dose-dependent increase in IL-6 secretion (14- to 27-fold at 50 ng/mL after 24 hours, P <.001). Conversely, rhIL-6 stimulated VEGF expression and secretion in myeloma cell lines (40%-60%; P <.05) and to a variable degree (up to 5.3-fold; P <.005) in plasma cells purified from the marrow of patients with MM. This mutual stimulation suggests paracrine interactions between myeloma and marrow stromal cells triggered by VEGF and IL-6. (Blood. 2000;95:2630-2636)

Overexpression of tissue-type plasminogen activator in atherosclerotic human coronary arteries

The plasminogen activator (PA)/plasmin system is involved in various pathological processes that are considered important features of atherogenesis and atherothrombosis. These include the proteolysis of fibrin deposits and extracellular matrix components as well as the induction of cell migration and mitogenesis. Tissue-type PA (TPA) is a key enzyme mediating plasminogen to plasmin conversion. TPA plasma concentrations are elevated in patients with advanced atherosclerosis and correlate with an increased risk for myocardial infarction and stroke. In this study, we have analysed the content and expression of TPA in human coronary arteries and their relation to the presence and severity of atherosclerotic lesions.

METHODS

Segments of coronary arteries obtained from heart explants (n = 15) were classified by the presence and types of atherosclerotic lesions. TPA was quantitatively determined in protein extracts of intimal and medial layers. In situ hybridization and immunohistochemical analyses were performed on serial sections of representative tissue specimens.

RESULTS

PA activity entirely attributable to the presence of active TPA was consistently detected in the protein extracts. Extractable TPA antigen and activity showed a significant graded increase in relation to the presence and severity of atherosclerotic lesions. The ratios of active over total TPA were increased several-fold in extracts of advanced lesions despite a concomitant threefold increase in TPA complexed to its inhibitor PA-1. In macroscopically normal arterial segments and in early lesions, TPA was expressed in the endothelium and in colocalization with vascular smooth muscle cells (VSMCs). In advanced plaques, TPA mRNA was mainly detected in the lateral regions of the fibrous caps in association with migrating VSMCs and in the vicinity of the core areas infiltrated by CD68-positive macrophages.

CONCLUSIONS

TPA content and expression is consistently increased in relation to the severity of the lesions in atherosclerotic coronary arteries. This may contribute to plaque destabilization and disruption. Conversely, the increased intramural TPA activity may counteract mural fibrin deposition.

Comparative analysis of plasminogen activator inhibitor-1 expression in different types of atherosclerotic lesions in coronary arteries from human heart explants

OBJECTIVES

Clinical manifestations of coronary heart disease result primarily from the progressive development of atherosclerotic plaques and subsequent thrombus formation: processes which may be accelerated by an enhanced expression of plasminogen activator inhibitor (PAI-1) in the vessel wall. In the present study, content and expression of PAI-1 were comparatively analyzed in human coronary arteries in relation to the presence and severity of atherosclerotic lesions.

METHODS

Segments of coronary arteries obtained from heart explants (n = 15) were classified by the presence and types of atherosclerotic lesions. Antigen and activity levels of PAI-1 were determined in protein extracts of intimal and medial layers. In situ hybridization and immunohistochemical analyses were performed on serial sections of representative tissue specimens.

RESULTS

Total PAI-1 antigen consistently increased from macroscopically normal areas (MNAs) to early lesions (ELs) and to maximal levels in fibrous (FPs) and calcified (CPs) plaques. No PAI activity was detected, although PAI-1 in its free form was present in all vascular specimens. Both free PAI-1 and PAI-1 complexed with plasminogen activators were significantly increased in extracts of advanced lesions. However, there was a 2-3 fold molar excess of free versus complexed PAI-1 in FPs and CPs. These findings suggest the presence of relevant amounts of PAI-1 in its substrate rather than in its inhibitor conformation in areas of advanced lesions. Compared with MNAs, PAI-1 mRNA was strongly expressed within the thickened intima of ELs. The highest PAI-1 expression was observed in FPs and CPs, being mainly localized in areas surrounding the necrotic cores in co-localization with infiltrating macrophages.

CONCLUSIONS

PAI-1 content is consistently increased in relation to the severity of the lesions in atherosclerotic coronary arteries. The concomitant elevation of PAI-1 mRNA suggests that the PAI-1 increase in regulated by local synthesis in the areas of atherosclerotic lesions.

Reciprocal changes in circulating interleukin-6 and its soluble receptor during evolving sepsis in leukocytopenic patients

Plasma concentrations of interleukin-6 (IL-6) and its soluble receptor (sIL-6R) were serially determined in 32 patients with acute myeloid leukemia who developed severe sepsis (n = 19) or septic shock (n = 13) during chemotherapy-induced leukocytopenia (< or = 1 x 10(9)/L). Starting within 2 h of fever onset, IL-6 levels rose significantly over baseline in both groups to markedly higher levels in patients with evolving septic shock (medians: 372 vs. 3671 pg/mL; P < .001). Simultaneously, sIL-6R significantly decreased to lower levels in shock patients than in septic patients without hypotension (53 vs. 93 ng/mL; P = .02). This pattern was maintained throughout the observation period of up to 6 days. In patients with fatal sepsis, peak IL-6 levels were significantly higher than in survivors (P < .001), whereas minimum sIL-6R levels were markedly lower (P = .003). The reciprocal changes in circulating IL-6 and sIL-6R suggest a role for sIL-6R in modulating the effects of IL-6 during evolving sepsis in leukocytopenic patients.

Factor VIIa and antithrombin III activity during severe sepsis and septic shock in neutropenic patients

Septic shock and multiple organ failure may be associated with coagulation activation, disseminated fibrin formation, and consumption of coagulation inhibitors such as antithrombin III. We have evaluated prospectively coagulation measurements in patients with severe chemotherapy-induced neutropenia. This group of patients was chosen because of their high risk of developing severe septic complications, thus allowing serial prospective coagulation testing before and during evolving sepsis or septic shock. Sixty-two patients with febrile infectious events were accrued to the study. Of these, 13 patients progressed to severe sepsis and 13 additional patients to septic shock as defined according to standard diagnostic criteria. At the onset of fever, factor (F) VIIa activity, FVII antigen and antithrombin III (AT III) activity decreased from normal baseline levels and were significantly lower in the group of patients who progressed to septic shock compared with those that developed severe sepsis (medians: 0.3 v 1.4 ng/mL, 21 v 86 U/dL and 45% v 95%; P < .001). The decrease of these measurements in septic shock was accompanied by an increase in prothrombin fragment 1+2 (median: 3.6 v 1.4 nmol/L; P = .05), a marker of thrombin generation. These differences were sustained throughout the septic episode (P < .0001). FVIIa and AT III levels of < 0.8 ng/mL and < 70%, respectively, at onset of fever predicted a lethal outcome with a sensitivity of 100% and 85%, and a specificity of 75% and 85%, respectively. In contrast, FXIIa-alpha antigen levels were not different between groups at onset of fever but increased modestly during the course of septic shock (P = .001). Thus, septic shock in neutropenic patients is associated with increased thrombin generation. Furthermore, both FVIIa and AT III measurements are sensitive markers of an unfavorable prognosis.

Increase of plasminogen activator inhibitor levels predicts outcome of leukocytopenic patients with sepsis

Variables of the fibrinolytic system were prospectively studied in patients with haematologic malignancies in chemotherapy-induced leukocytopenia at onset and during the course of septicemia to evaluate their prognostic value. This group of patients was chosen because of their high risk of developing severe septic complications, thus allowing serial prospective testing of fibrinolytic variables prior to and during evolving sepsis or septic shock. 62 patients with febrile infectious events were accrued to the study. Of these, 13 patients progressed to severe sepsis and an additional 13 patients to septic shock as defined according to standard diagnostic criteria. At onset of fever, plasminogen activator inhibitor (PAI) activity and PAI-1 antigen levels increased from normal baseline levels and were significantly higher in the group of patients who developed septic shock compared to those with severe sepsis (medians: 10.6 versus 1.3 U/ml, p = 0.0001; 50.0 versus 5.0 ng/ml, p = 0.0002). The increase in PAI activity and antigen in septic shock was accompanied by an increase in tissue-type plasminogen activator antigen and total fibrin(ogen) degradation products and a decrease in alpha(2)-antiplasmin activity (p < 0.006). In contrast, in the group of patients that developed severe sepsis the variables of the fibrinolytic system remained unchanged at onset of fever. These differences between septic shock and severe sepsis were sustained throughout the septic episode for all variables (p < 0.0001). PAI activity of > 5 U/ml at onset of fever predicted a lethal outcome with a sensitivity of 92% and a specificity of 100%. Thus, septic shock in leukocytopenia is associated with significant activation of the fibrinolytic system presumably as a response of the vascular endothelium to inflammatory injury. Furthermore, PAI activity measurements are sensitive markers of an unfavourable prognosis.

Markers of coagulation activation for evaluation of the antithrombotic efficacy of heparin: a prospective study in acute deep venous thrombosis

The potential value of measurements of prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin complexes (TAT) and D-dimer for the assessment of antithrombotic efficacy of heparin in acute deep venous thrombosis (DVT) was prospectively investigated. These variables were determined at presentation and subsequently once daily during a course of seven days heparin therapy. Heparin doses were adjusted according to the activated partial thromboplastin time (APTT). Compression ultrasonography was performed at presentation and on day 7 to determine the extent of thrombosis according to a predefined score. Out of a total of 50 patients accrued to the study 44 patients had reduced or unchanged extent of thrombosis, whereas in six patients an extension was documented. Although thrombin generation was significantly inhibited after initiation of heparin therapy as reflected by a decrease in F1 + 2 and TAT levels, these markers were not useful for the detection of patients with DVT extension. In contrast, anti-factor-Xa activities but not APTT measurements were significantly lower in the group of patients with propagation of DVT (median: 0.22 U/ml versus 0.38 U/ml, interquartile range: 0.1-0.33 U/ml versus 0.19-0.55 U/ml; P = 0.001). D-dimer decreased within the first days of heparin therapy but failed to indicate DVT progression. These data suggest that plasma anti-factor-Xa activity correlates better with the antithrombotic efficacy of heparin than APTT measurements and markers of coagulation or fibrinolysis activation.

Cytokine response to infection in patients with acute myelogenous leukaemia following intensive chemotherapy

Septic shock is the major cause of treatment-related death in patients with acute myelogenous leukaemia (AML) undergoing intensive chemotherapy. Interleukins (IL)-1 beta, -6, -8, and tumour necrosis factor alpha (TNF-alpha) have been implicated as mediators of septic shock, with circulating leucocytes being considered a major source for their release. However, plasma cytokine levels of leucocytopenic patients with evolving sepsis have not been studied. We have prospectively measured plasma cytokines during chemotherapy-induced leucocytopenia (< 1 x 10(9)/l) in 50 patients with AML. Cytokine levels in patients with severe sepsis (n = 5) or septic shock (n = 8) were compared to those measured in 13 matched patients with uncomplicated febrile infections. In evolving septic shock, IL-6, IL-8 and TNF-alpha peaked within 48 h of fever onset at levels reported for non-leucocytopenic patients and distinctively higher than during uncomplicated febrile episodes (P < 0.05). Peak concentrations measured within 48 h after onset of fever were related to fatal outcome. IL-1 beta was detected in less than 5% of all samples. Cytokine concentrations were unrelated to leucocyte counts and markers of neutrophil or monocyte activation (elastase and neopterin levels, respectively). We conclude that cytokine release associated with evolving septic shock in patients with AML does not depend on circulating leucocytes.

A novel exosite in the light chain of human activated protein C essential for interaction with blood coagulation factor Va

Activated protein C (APC) exerts its physiologic anticoagulant role by proteolytic inactivation of the blood coagulation cofactors Va and VIIIa. To identify regions on the surface of the light chain of APC that mediate anticoagulant activity, 10 synthetic peptides were prepared and tested for their ability to inhibit APC anticoagulant activity. The synthetic peptide-(142-155) inhibited APC anticoagulant activity in Xa-1-stage coagulation assays in normal and protein S-depleted plasma with 50% inhibition at 5-25 microM peptide. In a system using purified clotting factors, peptide-(142-155) inhibited APC catalyzed inactivation of factor Va in the presence or absence of phospholipids with 50% inhibition at 50 microM peptide. However, peptide-(142-155) had no effect on APC amidolytic activity or on the reaction of APC with the serpin, recombinant [Arg358]-alpha 1-antitrypsin. Moreover, peptide-(142-155) inhibited factor Xa clotting activity in normal plasma as well as in a prothrombinase assay in the presence of factor Va with 50% inhibition at 5 microM and 50 microM peptide, respectively, under the assay conditions. The peptide had no significant effect on factor Xa or thrombin amidolytic activity and no effect on the clotting of purified fibrinogen by thrombin, suggesting that it does not directly inhibit these enzymes' active sites. Peptide-(142-155) was shown to bind directly to immobilized factor Va.(ABSTRACT TRUNCATED AT 250 WORDS)

Interactions and inhibition of blood coagulation factor Va involving residues 311-325 of activated protein C

Activated protein C (APC) exerts its physiologic anticoagulant role by proteolytic inactivation of the blood coagulation cofactors Va and VIIIa. The synthetic peptide-(311-325) (KRNRTFVLNFIKIPV), derived from the heavy chain sequence of APC, potently inhibited APC anticoagulant activity in activated partial thromboplastin time (APTT) and Xa-1-stage coagulation assays in normal and in protein S-depleted plasma with 50% inhibition at 13 microM peptide. In a system using purified clotting factors, peptide-(311-325) inhibited APC-catalyzed inactivation of factor Va in the presence or absence of phospholipids with 50% inhibition at 6 microM peptide. However, peptide-(311-325) had no effect on APC amidolytic activity or on the reaction of APC with the serpin, recombinant [Arg358]alpha 1-antitrypsin. Peptide-(311-325) surprisingly inhibited factor Xa clotting activity in normal plasma, and in a purified system it inhibited prothrombinase activity in the presence but not in the absence of factor Va with 50% inhibition at 8 microM peptide. The peptide had no significant effect on factor Xa or thrombin amidolytic activity and no effect on the clotting of purified fibrinogen by thrombin, suggesting it does not directly inhibit these enzymes. Factor Va bound in a dose-dependent manner to immobilized peptide-(311-325). Peptide-(311-315) inhibited the binding of factor Va to immobilized APC or factor Xa.(ABSTRACT TRUNCATED AT 250 WORDS)

Binding of protein S to factor Va associated with inhibition of prothrombinase that is independent of activated protein C

Since plasma protein S serves an anticoagulant function by mechanisms which are not completely understood, its possible interaction with Factor Va was investigated. Human protein S bound to immobilized human Factor Va in a calcium-dependent, saturable, and reversible manner and Factor Va bound similarly to immobilized protein S. Binding of protein S to immobilized Factor V was greatly enhanced by pretreatment of the surface-bound Factor V with increasing doses of thrombin up to 1 unit/ml. Binding of protein S to Factor Va was also demonstrated in fluid phase with a Kd of 33 +/- 9 nM. Biotin-labeled heavy chain of Factor Va bound to immobilized protein S, and this binding was reversed by a 17-fold molar excess of intact unlabeled Factor Va. Protein S competed efficiently with prothrombin for binding to immobilized Factor Va. The prothrombinase activity in a reaction mixture of purified clotting factors was inhibited by protein S and exhibited a pattern of mixed inhibition. The concentration of protein S needed for 50% inhibition of the prothrombinase activity of a mixture containing 1 nM Factor Xa, 20 pM Factor Va, and 50 microM phospholipids was about 16 nM. Since not all protein S preparations exhibited this degree of prothrombinase inhibitory activity, extensive control experiments were performed to verify that the inhibitory activity was associated with protein S during immunoaffinity chromatography and was not caused by traces of activated protein C in the protein S preparations. These data show that protein S has an anticoagulant function which is independent of activated protein C and, at least in part, that this is because of its competition with prothrombin for direct binding to Factor Va.

Identification of a sequence of human activated protein C (residues 390-404) essential for its anticoagulant activity

Activated protein C (APC) exerts its physiologic anticoagulant role by proteolytic inactivation of the blood coagulation cofactors Va and VIIIa. To identify the regions on the surface that mediate anticoagulant activity, 26 synthetic peptides were prepared representing 90% of the human protein C heavy chain primary structure and tested for their ability to inhibit APC anticoagulant activity. Peptide-(390-404) specifically inhibited APC activity in activated partial thromboplastin time and Xa-1-stage coagulation assays in normal, in protein S-depleted and Factor VIII-deficient plasma with 50% inhibition at 5 microM peptide. Polyclonal antibodies raised against this peptide and immunoaffinity-purified on a protein C-Sepharose column inhibited APC anticoagulant activity in activated partial thromboplastin time and Xa-1-stage assays in normal, protein S-depleted, and Factor VIII-deficient plasma with half-maximal inhibition at 30 nM anti-(390-404) antibody. Neither the peptide-(390-404) nor the anti-(390-404) antibodies inhibited APC amidolytic activity or the reaction of APC with recombinant [Arg358] alpha 1-antitrypsin. Furthermore, in a purified system, peptide-(390-404) inhibited APC-catalyzed inactivation of Factor Va in the presence as well as in the absence of phospholipids with 50% inhibition at 4 microM peptide. These data suggest that the region containing residues 390-404 in APC is essential for anticoagulant activity and is available to interact with antibodies or with other proteins such as the macromolecular substrates Factors Va or VIIIa.