The Amino Acid Homoarginine Inhibits Atherogenesis by Modulating T-Cell Function.

BACKGROUND: Amino acid metabolism is crucial for inflammatory processes during atherogenesis. The endogenous amino acid homoarginine is a robust biomarker for cardiovascular outcome and mortality with high levels being protective. However, the underlying mechanisms remain elusive. We investigated the effect of homoarginine supplementation on atherosclerotic plaque development with a particular focus on inflammation. METHODS: Female ApoE-deficient mice were supplemented with homoarginine (14 mg/L) in drinking water starting 2 weeks before and continuing throughout a 6-week period of Western-type diet feeding. Control mice received normal drinking water. Immunohistochemistry and flow cytometry were used for plaque- and immunological phenotyping. T cells were characterized using mass spectrometry-based proteomics, by functional in vitro approaches, for example, proliferation and migration/chemotaxis assays as well as by super-resolution microscopy. RESULTS: Homoarginine supplementation led to a 2-fold increase in circulating homoarginine concentrations. Homoarginine-treated mice exhibited reduced atherosclerosis in the aortic root and brachiocephalic trunk. A substantial decrease in CD3+ T cells in the atherosclerotic lesions suggested a T-cell-related effect of homoarginine supplementation, which was mainly attributed to CD4+ T cells. Macrophages, dendritic cells, and B cells were not affected. CD4+ T-cell proteomics and subsequent pathway analysis together with in vitro studies demonstrated that homoarginine profoundly modulated the spatial organization of the T-cell actin cytoskeleton and increased filopodia formation via inhibition of Myh9 (myosin heavy chain 9). Further mechanistic studies revealed an inhibition of T-cell proliferation as well as a striking impairment of the migratory capacities of T cells in response to relevant chemokines by homoarginine, all of which likely contribute to its atheroprotective effects. CONCLUSIONS: Our study unravels a novel mechanism by which the amino acid homoarginine reduces atherosclerosis, establishing that homoarginine modulates the T-cell cytoskeleton and thereby mitigates T-cell functions important during atherogenesis. These findings provide a molecular explanation for the beneficial effects of homoarginine in atherosclerotic cardiovascular disease.

Vaccine-Induced Immune Thrombotic Thrombocytopenia (VITT): Targeting Pathomechanisms with Bruton Tyrosine Kinase Inhibitors.

A series of cases with rare thromboembolic incidents including cerebral sinus vein thrombosis (some of them fatal) and concomitant thrombocytopenia occurring shortly after vaccination with the coronavirus disease 2019 (COVID-19) vaccine AZD1222 (Vaxzevria) have caused significant concern and led to its temporary suspension in many countries. Immediate laboratory efforts in four of these patients have identified a tentative pathomechanism underlying this syndrome termed initially vaccine-induced prothrombotic immune thrombocytopenia (VIPIT) and renamed recently vaccine-induced immune thrombotic thrombocytopenia (VITT). It encompasses the presence of platelet-activating antibodies to platelet factor-4/heparin complexes, possibly emulated by polyanionic constituents of AZD1222, and thus resembles heparin-induced thrombocytopenia (HIT). Because these immune complexes bind and activate platelets via Fcγ receptor IIA (FcγRIIA), high-dose intravenous immunoglobulin G has been suggested for treatment of VITT in addition to non-heparin anticoagulants. Here we propose inhibitors of Bruton tyrosine kinase (Btk) approved for B cell malignancies (e.g., ibrutinib) as another therapeutic option in VITT, as they are expected to pleiotropically target multiple pathways downstream of FcγRIIA-mediated Btk activation, for example, as demonstrated for the effective inhibition of platelet aggregation, dense granule secretion, P-selectin expression and platelet-neutrophil aggregate formation stimulated by FcγRIIA cross-linking. Moreover, C-type lectin-like receptor CLEC-2- and GPIb-mediated platelet activation, the interactions and activation of monocytes and the release of neutrophil extracellular traps, as encountered in HIT, could be attenuated by Btk inhibitors. As a paradigm for emergency repurposing of approved drugs in COVID-19, off-label use of Btk inhibitors in a low-dose range not affecting haemostatic functions could thus be considered a sufficiently safe option to treat VITT.

Inositol-requiring enzyme-1 regulates phosphoinositide signaling lipids and macrophage growth.

The ER-bound kinase/endoribonuclease (RNase), inositol-requiring enzyme-1 (IRE1), regulates the phylogenetically most conserved arm of the unfolded protein response (UPR). However, the complex biology and pathology regulated by mammalian IRE1 cannot be fully explained by IRE1's one known, specific RNA target, X box-binding protein-1 (XBP1) or the RNA substrates of IRE1-dependent RNA degradation (RIDD) activity. Investigating other specific substrates of IRE1 kinase and RNase activities may illuminate how it performs these diverse functions in mammalian cells. We report that macrophage IRE1 plays an unprecedented role in regulating phosphatidylinositide-derived signaling lipid metabolites and has profound impact on the downstream signaling mediated by the mammalian target of rapamycin (mTOR). This cross-talk between UPR and mTOR pathways occurs through the unconventional maturation of microRNA (miR) 2137 by IRE1's RNase activity. Furthermore, phosphatidylinositol (3,4,5) phosphate (PI(3,4,5)P3 ) 5-phosphatase-2 (INPPL1) is a direct target of miR-2137, which controls PI(3,4,5)P3 levels in macrophages. The modulation of cellular PI(3,4,5)P3 /PIP2 ratio and anabolic mTOR signaling by the IRE1-induced miR-2137 demonstrates how the ER can provide a critical input into cell growth decisions.

Designed CXCR4 mimic acts as a soluble chemokine receptor that blocks atherogenic inflammation by agonist-specific targeting.

Targeting a specific chemokine/receptor axis in atherosclerosis remains challenging. Soluble receptor-based strategies are not established for chemokine receptors due to their discontinuous architecture. Macrophage migration-inhibitory factor (MIF) is an atypical chemokine that promotes atherosclerosis through CXC-motif chemokine receptor-4 (CXCR4). However, CXCR4/CXCL12 interactions also mediate atheroprotection. Here, we show that constrained 31-residue-peptides ('msR4Ms') designed to mimic the CXCR4-binding site to MIF, selectively bind MIF with nanomolar affinity and block MIF/CXCR4 without affecting CXCL12/CXCR4. We identify msR4M-L1, which blocks MIF- but not CXCL12-elicited CXCR4 vascular cell activities. Its potency compares well with established MIF inhibitors, whereas msR4M-L1 does not interfere with cardioprotective MIF/CD74 signaling. In vivo-administered msR4M-L1 enriches in atherosclerotic plaques, blocks arterial leukocyte adhesion, and inhibits atherosclerosis and inflammation in hyperlipidemic Apoe-/- mice in vivo. Finally, msR4M-L1 binds to MIF in plaques from human carotid-endarterectomy specimens. Together, we establish an engineered GPCR-ectodomain-based mimicry principle that differentiates between disease-exacerbating and -protective pathways and chemokine-selectively interferes with atherosclerosis.

Impact of Intraoperative Cell Salvage on Blood Coagulation Factor Concentrations in Patients Undergoing Cardiac Surgery.

BACKGROUND: Cardiothoracic surgery is associated with major blood loss and allogeneic transfusion of red blood cell concentrates. To minimize allogeneic red blood cell (RBC) transfusion, intraoperative cell salvage has been effectively used for years. The objective of this study was to evaluate the impact of cell salvage on blood coagulation factors. METHODS: We enrolled 30 patients scheduled for cardiac surgery in a prospective single-center observational cohort study at an academic hospital. Blood samples from the cell salvage system were obtained from both the reservoir and the processed red blood cell concentrate. Coagulation factors, fibrinogen, antithrombin and von Willebrand activity, and antigen were assessed before and after cell salvage. Statistical analysis was performed using Wilcoxon matched-pairs signed rank test. RESULTS: Our results revealed a significant decrease of fibrinogen (P < .001), coagulation factors II (P = .004), factors VII, X, and XIII (P < .001), and all other measured coagulation factor concentrations/activities in the processed red blood cell concentrate, when compared to the concentrations/activities of the reservoir. CONCLUSIONS: The results of the present study revealed a significant reduction of coagulation factor concentrations/activities by the washing process. Therefore, physicians need to consider adequate management of coagulation in patients with major blood loss and the need of large volumes of RBC transfusion.

High dose rosuvastatin increases ABCA1 transporter in human atherosclerotic plaques in a cholesterol-independent fashion.

BACKGROUND: ATP-binding cassette A1 (ABCA1) and G1 (ABCG1) mediate cholesterol efflux from lipid-laden macrophages, thus promoting anti-atherosclerotic outcomes. The mechanism(s) linking treatment with statins and ABCA1/ABCG1 in human atherosclerosis are not fully understood and require further investigation. Therefore, we studied whether short-term treatment with low- or high-dose rosuvastatin may affect ABCA1 and ABCG1 expression in human atherosclerotic plaques. METHODS: Seventy patients with severe stenosis of the internal carotid artery were randomized to receive low (10 mg/day) or high (40 mg/day) dose rosuvastatin for 12 weeks before elective endarterectomy. As controls, we analyzed a reference group of 10 plaques from subjects with hypercholesterolemia but not receiving statin treatment and an additional set of 11 plaques collected from normocholesterolemic patients. On atherosclerotic plaques, ABCA1 and ABCG1 expression was evaluated at RNA level by qPCR and at protein level by immunoblotting and immunohistochemistry. RESULTS: Both rosuvastatin doses were associated with lower plaque ABCA1 mRNA levels and with a trend toward reduction for ABCG1. However, ABCA1 protein was paradoxically higher in patients treated with high-dose rosuvastatin and was associated with lower levels of miR-33b-5p, a microRNA known as a regulator of ABCA1. Multivariate analyses showed that the effect is cholesterol-independent. Finally, no effects were found for ABCG1 protein. CONCLUSIONS: High-dose rosuvastatin increases macrophage ABCA1 protein levels in human atherosclerotic plaque despite mRNA reduction in a mechanism unrelated to plasma cholesterol reduction and potentially involving miR-33b-5p. This pathway may reflect an additional feature contributing to the anti-atherosclerotic effect for high-dose rosuvastatin. TRIAL REGISTRATION: ISRCTN16590640.

Btk Inhibitors as First Oral Atherothrombosis-Selective Antiplatelet Drugs?

Bruton's tyrosine kinase (Btk) is essential for B cell differentiation and proliferation, but also platelets express Btk. Patients with X-linked agammaglobulinemia due to hereditary Btk deficiency do not show bleeding, but a mild bleeding tendency is observed in high dose therapy of B-cell malignancies with ibrutinib and novel second-generation irreversible Btk inhibitors (acalabrutinib and ONO/GS-4059). This review discusses recent studies that may explain this apparent paradox and gives mechanistic insights that suggest a unique potential of low dose irreversible Btk inhibitors as atherothrombosis-focused antiplatelet drugs.

Blocking CCL5-CXCL4 heteromerization preserves heart function after myocardial infarction by attenuating leukocyte recruitment and NETosis.

Myocardial infarction (MI) is a major cause of death in Western countries and finding new strategies for its prevention and treatment is thus of high priority. In a previous study, we have demonstrated a pathophysiologic relevance for the heterophilic interaction of CCL5 and CXCL4 in the progression of atherosclerosis. A specifically designed compound (MKEY) to block this CCL5-CXCR4 interaction is investigated as a potential therapeutic in a model of myocardial ischemia/reperfusion (I/R) damage. 8 week-old male C57BL/6 mice were intravenously treated with MKEY or scrambled control (sMKEY) from 1 day before, until up to 7 days after I/R. By using echocardiography and intraventricular pressure measurements, MKEY treatment resulted in a significant decrease in infarction size and preserved heart function as compared to sMKEY-treated animals. Moreover, MKEY treatment significantly reduced the inflammatory reaction following I/R, as revealed by specific staining for neutrophils and monocyte/macrophages. Interestingly, MKEY treatment led to a significant reduction of citrullinated histone 3 in the infarcted tissue, showing that MKEY can prevent neutrophil extracellular trap formation in vivo. Disrupting chemokine heterodimers during myocardial I/R might have clinical benefits, preserving the therapeutic benefit of blocking specific chemokines, and in addition, reducing the inflammatory side effects maintaining normal immune defence.

Epithelial magnesium transport by TRPM6 is essential for prenatal development and adult survival.

Mg2+ regulates many physiological processes and signalling pathways. However, little is known about the mechanisms underlying the organismal balance of Mg2+. Capitalizing on a set of newly generated mouse models, we provide an integrated mechanistic model of the regulation of organismal Mg2+ balance during prenatal development and in adult mice by the ion channel TRPM6. We show that TRPM6 activity in the placenta and yolk sac is essential for embryonic development. In adult mice, TRPM6 is required in the intestine to maintain organismal Mg2+ balance, but is dispensable in the kidney. Trpm6 inactivation in adult mice leads to a shortened lifespan, growth deficit and metabolic alterations indicative of impaired energy balance. Dietary Mg2+ supplementation not only rescues all phenotypes displayed by Trpm6-deficient adult mice, but also may extend the lifespan of wildtype mice. Hence, maintenance of organismal Mg2+ balance by TRPM6 is crucial for prenatal development and survival to adulthood.

Expression of surface-associated 82kDa-proMMP-9 in primary acute leukemia blast cells inversely correlates with patients' risk.

With its ability to degrade extracellular matrix proteins and activate growth factors and cytokines, matrix metalloproteinase (MMP)-9 is an important regulator of cell function. Previously, we reported that myeloid leukemic cells express a unique 82kDa-proMMP-9 variant on their cell surface that is not affected by its natural inhibitor. In this study, we generated monoclonal antibodies that specifically recognize 82kDa-proMMP-9. Flow cytometry analysis using these antibodies revealed significant surface expression of 82kDa-proMMP-9 in monocytes, but minimal amounts in T and B cells isolated from peripheral blood of nine healthy donors and 22 patients with acute myeloid leukemia (AML). In all AML patients, blasts expressed 82kDa-proMMP-9 at levels of 4%-46%, with significantly higher levels in patients with a better risk defined according to National Comprehensive Cancer Network (NCCN) guidelines (ρ = -0.748, p < 0.001) and favorable phenotype according to the French-American-British classification (p = 0.02) compared with patients with adverse prognoses. Receiver operating characteristic curve analysis confirmed the diagnostic accuracy of 82kDa-proMMP-9 measurement in AML blasts (area under the curve: 0.893 [0.739-1.000], p = 0.019). It led us to define a cutoff value of 11.5% for identifying patients with lower NCCN risk (p = 0.005) and with a tendency toward a higher probability of response to anthracycline-based therapy (p = 0.109) and increased event-free survival (p = 0.24). Thus, 82kDa-proMMP-9 expression on blasts may represent a novel independent marker of prognosis in patients with AML.

Electroless preparation and ASAXS microstructural analysis of pseudocapacitive carbon manganese oxide supercapacitor electrodes.

Anomalous small angle X-ray scattering (ASAXS) has been utilized as a noninvasive, integral tool to access the structural properties of carbon xerogel-manganese oxide electrodes with nanometer resolution. As these electrodes constitute the elementary functional units in supercapacitors and as their microstructure governs the macroscopic electrical performance, it is essential to gain a detailed morphological understanding of the underlying carbon particle scaffold coated with manganese oxide. We demonstrate that, in this regard, ASAXS provides a powerful technique and in combination with a theoretical core-shell model enables a quantitative estimation of the relevant structural parameters. As a result, we determined the thicknesses of the solution deposited MnO2 shells to range between 3 and 26 nm depending on the carbon particle size and thus on their effective surface area. By our core-shell modeling we conclude the revealed manganese oxide coatings on the carbon support to be rather thick, but nevertheless to show a high uniformity in thickness. At 1.8 ± 0.2 to 2.2 ± 0.1 g/cm(3) the related effective MnO2 densities of the shells are about 30% lower than the corresponding bulk density of 3.0 g/cm(3). This mainly originates from a substructure within the shell, whose growth is controlled by a pronounced reduction of the manganese precursor during layer formation. Finally, the presented ASAXS data are complemented by SEM and N2 sorption measurements, proving not only qualitatively the proposed flake-like MnO2 surface morphology but also confirming quantitatively the manganese shell thickness, complementary, on a local scale.

Bioassay-guided fractionation of extracts from Codiaeum variegatum against Entamoeba histolytica discovers compounds that modify expression of ceramide biosynthesis related genes.

Leaves of Codiaeum variegatum ("garden croton") are used against bloody diarrhoea by local populations in Cameroon. This study aims to search for the active components from C. variegatum against Entamoeba histolytica, and thereby initiate the study of their mechanism of action. A bioassay-guided screening of the aqueous extracts from C. variegatum leaves and various fractions was carried out against trophozoites of E. histolytica axenic culture. We found that the anti-amoebic activity of extracts changed with respect to the collection criteria of leaves. Thereby, optimal conditions were defined for leaves' collection to maximise the anti-amoebic activity of the extracts. A fractionation process was performed, and we identified several sub-fractions (or isolated compounds) with significantly higher anti-amoebic activity compared to the unfractionated aqueous extract. Anti-amoebic activity of the most potent fraction was confirmed with the morphological characteristics of induced death in trophozoites, including cell rounding and lysis. Differential gene expression analysis using high-throughput RNA sequencing implies the potential mechanism of its anti-amoebic activity by targeting ceramide, a bioactive lipid involved in disturbance of biochemical processes within the cell membrane including differentiation, proliferation, cell growth arrest and apoptosis. Regulation of ceramide biosynthesis pathway as a target for anti-amoebic compounds is a novel finding which could be an alternative for drug development against E. histolytica.

Impact of general versus local anesthesia on early postoperative cognitive dysfunction following carotid endarterectomy: GALA Study Subgroup Analysis.

BACKGROUND: The aim of this study was to compare the influence of either general (GA) or local (LA) anesthesia on the postoperative neurocognitive outcome in patients undergoing carotid endarterectomy (CEA) in a randomized study. Therefore, we performed a subgroup analysis of the multicenter GALA study. METHODS: A total of 40 patients were enrolled and randomized to receive either LA (n = 17) or GA (n = 23) anesthesia. The indication for intraoperative shunting was based on the intraoperative cognitive performance in the LA group and on the clinical experience of the surgeon in the GA group. Outcome measurements included patient performance on a neuropsychological Trail Making Test, evaluation of patients mood using the self-report inventory BSKE, and serum levels of the neurobiochemical marker S100beta. The data were analyzed for each variable using a t-test and were presented as the mean (SD). Differences in shunt frequency were analyzed performing a chi-squared test. Group differences in the Trail Making Test, BSKE evaluation, and S100beta concentrations were derived from the analyses of covariances with repeated measurements using preoperative values as covariates. RESULTS: Compared to baseline, the S100beta concentrations increased significantly in the GA group [0.086 (0.038) vs. 0.061 (0.024) microg/l; p < 0.001] before unclamping of the carotid artery, whereas there were no changes in the LA group [0.068 (0.024) microg/l, p = 0.09 vs. 0.061 (0.021) microg/l, p = 0.09). Furthermore, we detected significant group differences after surgical intervention (GA 0.087 (0.031) microg/l; LA 0.06 (0.021) microg/l; p = 0.006). The postoperative neurocognitive performance in the Trail Making Test decreased significantly in the GA group, whereas there were no significant changes in the LA group. The self-report inventory BSKE evaluation revealed no significant group differences. CONCLUSIONS: We concluded that performing local anesthesia in patients undergoing CEA positively influenced early postoperative neurocognitive outcomes. Significant group differences in postoperative S100beta concentrations confirmed the beneficial effect of local anesthesia.

Caffeine enhances endothelial repair by an AMPK-dependent mechanism.

OBJECTIVE: Migratory capacity of endothelial progenitor cells (EPCs) and mature endothelial cells (ECs) is a key prerequisite for endothelial repair after denuding injury or endothelial damage. METHODS AND RESULTS: We demonstrate that caffeine in physiologically relevant concentrations (50 to 100 micromol/L) induces migration of human EPCs as well as mature ECs. In patients with coronary artery disease (CAD), caffeinated coffee increased caffeine serum concentration from 2 micromol/L to 23 micromol/L, coinciding with a significant increase in migratory activity of patient-derived EPCs. Decaffeinated coffee neither affected caffeine serum levels nor migratory capacity of EPCs. Treatment with caffeine for 7 to 10 days in a mouse-model improved endothelial repair after denudation of the carotid artery. The enhancement of reendothelialization by caffeine was significantly reduced in AMPK knockout mice compared to wild-type animals. Transplantation of wild-type and AMPK(-/-) bone marrow into wild-type mice revealed no difference in caffeine challenged reendothelialization. ECs which were depleted of mitochondrial DNA did not migrate when challenged with caffeine, suggesting a potential role for mitochondria in caffeine-dependent migration. CONCLUSIONS: These results provide evidence that caffeine enhances endothelial cell migration and reendothelialization in part through an AMPK-dependent mechanism, suggesting a beneficial role for caffeine in endothelial repair.

Anti-atherosclerotic properties of telmisartan in advanced atherosclerotic lesions in apolipoprotein E deficient mice.

Clinical studies have demonstrated that the inhibition of the renin-angiotensin system (RAS) by either an angiotensin-converting enzyme (ACE)-inhibitor or an angiotensin II receptor type 1 (AT(1))-antagonist reduces cardiovascular disease. The objective of this study was to evaluate underlying mechanisms of the AT(1)-antagonist telmisartan in comparison to the ACE-inhibitor ramipril on advanced atherosclerotic lesions. Thirty-two-week-old apolipoprotein E deficient mice (n=60) exhibiting advanced atherosclerotic lesions were fed a chow diet supplemented with ramipril or telmisartan for 16 weeks. Twenty mice received a standard diet. Mice receiving telmisartan had a 38% and mice receiving ramipril had a 18% reduction in progression of atherosclerotic lesion size within the innominate artery. Signs of plaque instability such as frequency of intra-plaque hemorrhage and size of the necrotic cores were reduced in mice receiving telmisartan. Furthermore, telmisartan-treated mice had fewer macrophages and reduced expression of early growth response gene-1 (Egr-1) within the lesions. Electrophoretic mobility shift assays revealed reduced DNA-binding activity of nuclear factor kappaB (NFkappaB) in the aorta of telmisartan-treated mice. In vitro studies in mouse macrophages demonstrated enhanced promoter activation of the nuclear transcription factor peroxisome proliferators-activated receptor gamma (PPARgamma). Target genes of PPARgamma, such as inducible nitric oxide synthase, NFkappaB and Egr-1, showed reduced activity after telmisartan pretreatment. These data suggest that chronic inhibition of the RAS by telmisartan prevails in reducing advanced atherosclerosis and promoting plaque stability over ramipril, possibly through the reduced activity of the pro-inflammatory transcription factors NFkappaB and Egr-1 and through the activation of PPARgamma.

Indium-111 oxine labelling affects the cellular integrity of haematopoietic progenitor cells.

PURPOSE: Cell-based therapy by transplantation of progenitor cells has emerged as a promising development for organ repair, but non-invasive imaging approaches are required to monitor the fate of transplanted cells. Radioactive labelling with (111)In-oxine has been used in preclinical trials. This study aimed to validate (111)In-oxine labelling and subsequent in vivo and ex vivo detection of haematopoietic progenitor cells. METHODS: Murine haematopoietic progenitor cells (10(6), FDCPmix) were labelled with 0.1 MBq (low dose) or 1.0 MBq (high dose) (111)In-oxine and compared with unlabelled controls. Cellular retention of (111)In, viability and proliferation were determined up to 48 h after labelling. Labelled cells were injected into the cavity of the left or right cardiac ventricle in mice. Scintigraphic images were acquired 24 h later. Organ samples were harvested to determine the tissue-specific activity. RESULTS: Labelling efficiency was 75 +/- 14%. Cellular retention of incorporated (111)In after 48 h was 18 +/- 4%. Percentage viability after 48 h was 90 +/- 1% (control), 58 +/- 7% (low dose) and 48 +/- 8% (high dose) (p<0.0001). Numbers of viable cells after 48 h (normalised to 0 h) were 249 +/- 51% (control), 42 +/- 8% (low dose) and 32 +/- 5% (high dose) (p<0.0001). Cells accumulated in the spleen (86.6 +/- 27.0% ID/g), bone marrow (59.1 +/- 16.1% ID/g) and liver (30.3 +/- 9.5% ID/g) after left ventricular injection, whereas most of the cells were detected in the lungs (42.4 +/- 21.8% ID/g) after right ventricular injection. CONCLUSION: Radiolabelling of haematopoietic progenitor cells with (111)In-oxine is feasible, with high labelling efficiency but restricted stability. The integrity of labelled cells is significantly affected, with substantially reduced viability and proliferation and limited migration after systemic transfusion.

In-line filtration of autologous whole blood.

BACKGROUND: Experimental data suggest that autologous white blood cells (WBCs) might exert an immunomodulatory effect. Leukodepletion of autologous blood is considered to prevent this unwanted side effect of autologous transfusion. In some cases, however, prolonged filtration or filtration failures occur. Because such autologous units cannot simply be discarded, the interest was in the storage variables of autologous whole blood (AWB) units after prolonged filtration. STUDY DESIGN AND METHODS: AWB of patients undergoing orthopedic surgery was leukodepleted before storage or left unmodified. Filtration times, volume, WBC count, hemoglobin level, hemolysis, potassium, and ATP were determined in all units with filtration times of more than 60 minutes that had not been transfused by the time of expiry and in representative samples of units that had been filtered normally or that had not been filtered. RESULTS: In AWB filtration, the rate of prolonged filtrations or filter blockades is three to four times higher than in allogeneic whole-blood filtration. Filtration or prolonged filtration leads to a mean loss of red blood cell (RBC) mass of 7.3 or 18.2 percent, respectively. Even in units with filtration times of more than 3 hours, storage variables were not significantly different from normally filtered or unfiltered units. Filtration times showed a high intraindividual correlation. CONCLUSION: Leukodepletion of AWB results in a diminished preoperative deposit of RBCs that is pronounced in units with prolonged filtration. The quality of the latter suggests that it is not justified to discard AWB units with prolonged filtration times. Prolonged filtrations are related to patient characteristics that have yet to be defined.

HMG-CoA reductase inhibitor simvastatin profoundly improves survival in a murine model of sepsis.

BACKGROUND: HMG-CoA reductase inhibitors, such as simvastatin, have been shown to exhibit pronounced immunomodulatory effects independent of lipid lowering but to date have not been used to treat severe inflammatory disease such as sepsis. We thus approached the question of whether treatment with simvastatin might improve cardiovascular function and survival in sepsis. METHODS AND RESULTS: Mice treated with simvastatin and rendered septic by cecal ligation and perforation (CLP) show a mean survival time close to 4 times the value found in untreated mice. This dramatic improvement is based on a complete preservation of cardiac function and hemodynamic status, which are severely impaired in untreated CLP mice [eg, 20 hours after CLP, cardiac output declined from 1.24+/-0.09 to 0.87+/-0.11 mL x min(-1) x g(-1) in untreated mice (P<0.005; n=12), while remaining unaltered (1.21+/-0.08 mL x min(-1) x g(-1) at baseline and 1.15+/-0.1 mL x min(-1) x g(-1) 20 hours after CLP, P=NS, n=12) in CLP mice treated with simvastatin]. Untreated CLP mice remained refractory to beta-stimulation, whereas the responsiveness to dobutamine was restored by treatment with simvastatin. Susceptibility of coronary flow to endothelial nitric oxide synthase (eNOS) stimulation by bradykinin was close to 3 times as pronounced in untreated CLP mice as in untreated sham-operated mice, indicating a high level of eNOS activation secondary to sepsis. In addition, treatment with simvastatin reversed inflammatory alterations in CLP mice, namely, increased monocyte adhesion to endothelium. CONCLUSIONS: Simvastatin, which is well established in the treatment of lipid disorders and coronary artery disease, might have the additional potential of being an effective agent in sepsis treatment.

Mitochondria play a central role in apoptosis induced by alpha-tocopheryl succinate, an agent with antineoplastic activity: comparison with receptor-mediated pro-apoptotic signaling.

alpha-Tocopheryl succinate (alpha-TOS) is a semisynthetic vitamin E analogue with high pro-apoptotic and anti-neoplastic activity [Weber, T et al. (2002) Clin. Cancer Res. 8, 863-869]. Previous studies suggested that it acts through destabilization of subcellular organelles, including mitochondria, but compelling evidence is missing. Cells treated with alpha-TOS showed altered mitochondrial structure, generation of free radicals, activation of the sphingomyelin cycle, relocalization of cytochrome c and Smac/Diablo, and activation of multiple caspases. A pan-caspase inhibitor suppressed caspase-3 and -6 activation and phosphatidyl serine externalization, but not decrease of mitochondrial membrane potential or generation of radicals. For alpha-TOS, but not Fas or TRAIL, apoptosis was suppressed by caspase-9 inhibition, while TRAIL- and Fas-resistant cells overexpressing cFLIP or CrmA were susceptible to alpha-TOS. The central role of mitochondria was confirmed by resistance of mtDNA-deficient cells to alpha-TOS, by regulation of alpha-TOS apoptosis by Bcl-2 family members, and by anti-apoptotic activity of mitochondrially targeted radical scavengers. Co-treatment with alpha-TOS and anti-Fas IgM showed their cooperative effect, probably by signaling via different, convergent pathways. These data provide an insight into the molecular mechanism, by which alpha-TOS kills malignant cells, and advocate its testing as a potential anticancer agent or adjuvant.

Vitamin E succinate is a potent novel antineoplastic agent with high selectivity and cooperativity with tumor necrosis factor-related apoptosis-inducing ligand (Apo2 ligand) in vivo.

Alpha-tocopheryl succinate (alpha-TOS), a redox-inactive analogue of vitamin E, is a strong inducer of apoptosis, whereas alpha-tocopherol (alpha-TOH) lacks apoptogenic activity (J. Neuzil et al., FASEB J., 15: 403-415, 2001). Here we investigated the possible antineoplastic activities of alpha-TOH and alpha-TOS and further explored the potential of alpha-TOS as an antitumor agent. Using nude mice with colon cancer xenografts, we found that alpha-TOH exerted modest antitumor activity and acted by inhibiting tumor cell proliferation. In contrast, alpha-TOS showed a more profound antitumor effect, at both the level of inhibition of proliferation and induction of tumor cell apoptosis. alpha-TOS was nontoxic to normal cells and tissues, triggered apoptosis in p53(-/-) and p21(Waf1/Cip1(-/-)) cancer cells, and exerted a cooperative proapoptotic activity with tumor necrosis factor-related apoptosis-inducing ligand (Apo2 ligand) due to differences in proapoptotic signaling. Finally, alpha-TOS cooperated with tumor necrosis factor-related apoptosis-inducing ligand in suppression of tumor growth in vivo. Vitamin E succinate is thus a potent and highly specific anticancer agent and/or adjuvant of considerable therapeutic potential.