RESUMEN
PURPOSE: To study the use of in silica model to better understand and propose new markers of ovarian response to controlled ovarian stimulation before IVF. METHODS: A systematic review and in silica model using bioinformatics. After the selection of 103 papers from a systematic review process, we performed a GRADE qualification of all included papers for evidence-based quality evaluation. We included 57 genes in the silica model using a functional protein network interaction. Moreover, the construction of protein-protein interaction network was done importing these results to Cytoscape. Therefore, a cluster analysis using MCODE was done, which was exported to a plugin BINGO to determine Gene Ontology. A p value of < 0.05 was considered significant, using a Bonferroni correction test. RESULTS: In silica model was robust, presenting an ovulation-related gene network with 87 nodes (genes) and 348 edges (interactions between the genes). Related to the network centralities, the network has a betweenness mean value = 102.54; closeness mean = 0.007; and degree mean = 8.0. Moreover, the gene with a higher betweenness was PTPN1. Genes with the higher closeness were SRD5A1 and HSD17B3, and the gene with the lowest closeness was GDF9. Finally, the gene with a higher degree value was UBB; this gene participates in the regulation of TP53 activity pathway. CONCLUSIONS: This systematic review demonstrated that we cannot use any genetic marker before controlled ovarian stimulation for IVF. Moreover, in silica model is a useful tool for understanding and finding new markers for an IVF individualization. PROSPERO: CRD42020197185.
Asunto(s)
Fertilización In Vitro , Ovario/metabolismo , Inducción de la Ovulación , Mapas de Interacción de Proteínas/genética , Biología Computacional , Simulación por Computador , Femenino , Redes Reguladoras de Genes/genética , Humanos , Ovario/crecimiento & desarrollo , PronósticoRESUMEN
OBJECTIVES: National and international guidelines recommend empiric first-line treatments of individuals infected with Helicobacter pylori without prior antimicrobial susceptibility testing. For this reason, knowledge of primary resistance to first-line antibiotics such as clarithromycin is essential. We assessed the primary resistance of H. pylori in Germany to key antibiotics by molecular genetic methods and evaluated risk factors for the development of resistance. METHODS: Gastric tissue samples of 1851 yet treatment-naïve H. pylori-positive patients were examined with real-time PCR or PCR and Sanger sequencing for mutations conferring resistance to clarithromycin, levofloxacin and tetracycline. Clinical and epidemiological data were documented and univariable and multivariable logistic regression analyses were conducted. RESULTS: Overall primary resistances were 11.3% (210/1851) to clarithromycin, and 13.4% (201/1497) to levofloxacin; resistance to tetracycline (2.5%, 38/1497) was as low as combined resistance to clarithromycin/levofloxacin (2.6%, 39/1497). Female sex and prior antimicrobial therapies owing to unrelated bacterial infections were risk factors for clarithromycin resistance (adjusted OR (aOR) 2.3, 95% CI 1.6-3.4; and 2.6, 95% CI 1.5-4.5, respectively); older age was associated with levofloxacin resistance (aOR for those ≥65 years compared with those 18-35 years: 6.6, 95% CI 3.1-14.2). CONCLUSIONS: Clarithromycin might still be recommended in first-line eradication therapies in yet untreated patients, but as nearly every tenth patient may carry clarithromycin-resistant H. pylori it may be advisable to rule out resistance ahead of treatment by carrying out susceptibility testing or prescribing an alternative therapy.
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Antibacterianos/farmacología , Farmacorresistencia Bacteriana Múltiple/genética , Helicobacter pylori/efectos de los fármacos , Adolescente , Adulto , Factores de Edad , Anciano , Claritromicina/farmacología , Femenino , Alemania/epidemiología , Infecciones por Helicobacter/tratamiento farmacológico , Infecciones por Helicobacter/epidemiología , Infecciones por Helicobacter/microbiología , Helicobacter pylori/genética , Humanos , Levofloxacino/farmacología , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Mutación , Factores de Riesgo , Factores Sexuales , Tetraciclina/farmacología , Adulto JovenRESUMEN
C1-esterase inhibitor (C1-Inh) therapy was introduced in clinical medicine about 25 years ago as a replacement therapy for patients with hereditary angioedema caused by a deficiency of C1-Inh. There is now accumulating evidence, obtained from studies in animals and observations in patients, that administration of C1-Inh may have a beneficial effect as well in other clinical conditions such as sepsis, cytokine-induced vascular leak syndrome, acute myocardial infarction, or other diseases. Activation of the complement system, the contact activation system, and the coagulation system has been observed in these diseases. A typical feature of the contact and complement system is that on activation they give rise to vasoactive peptides such as bradykinin or the anaphylatoxins, which in part explains the proinflammatory effects of either system. C1-Inh, belonging to the superfamily of serine proteinase inhibitors (serpins), is a major inhibitor of the classical complement pathway, the contact activation system, and the intrinsic pathway of coagulation, respectively. It is, therefore, endowed with anti-inflammatory properties. However, inactivation of C1-Inh occurs locally in inflamed tissues by proteolytic enzymes (e.g., elastase) released from activated neutrophils or bacteria thereby leading to increased local activation of the various host defense systems. Here we will give an overview on the biochemistry and biology of C1-Inh. We will discuss studies addressing therapeutic administration of C1-Inh in experimental and clinical conditions. Finally, we will provide an explanation for the therapeutic benefit of C1-Inh in so many different diseases.
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Antiinflamatorios no Esteroideos/uso terapéutico , Proteínas Inactivadoras del Complemento 1/uso terapéutico , Inflamación/tratamiento farmacológico , Animales , Proteínas Inactivadoras del Complemento 1/fisiología , Proteína Inhibidora del Complemento C1 , Glicosaminoglicanos/metabolismo , Humanos , Leucocitos/efectos de los fármacosRESUMEN
The role of plasma cholesteryl ester transfer and lipid transfer proteins in atherosclerosis is unclear. Recent data suggest both antiatherogenic and atherogenic properties for cholesteryl ester transfer protein (CETP). The overall effect of CETP on atherosclerosis may thus vary depending on individual lipid metabolism. To test whether lipid transfer parameters are of importance even in patients without major lipid risk factors for atherosclerosis, CETP mass and activity, net mass transfer of cholesteryl esters between endogenous lipoproteins (CET), and phospholipid transfer protein (PLTP) activity were determined in plasma from 18 normolipidemic male patients with peripheral vascular disease and 21 controls. Furthermore, lecithin: cholesterol acyltransferase (LCAT) activity was tested. The results show that CETP mass, CETP activity, and LCAT activity are not different between patients and controls. However, specific CETP activity (CETP activity/CETP mass) is lower in the patients (P < .02). On the contrary, higher CET is observed in patients' plasma (P < .001). Increased plasma PLTP activity (P = .052) is demonstrable in the patients. If the data of all subjects are combined, CET correlates positively with triglycerides ([TG], r = .45, P < .001) and with PLTP activity (r = .32, P < .05) but negatively with specific CETP activity (r = -.37 P < .05). CET and specific CETP activity remain significantly different in TG-matched patients and controls and are more strongly interrelated (r = -.71, P < .001), suggesting a higher and selective influence of lipid transfer inhibitor(s) on CET and CETP activity in the patients. CET allows the best discrimination between patients and controls in univariate and multivariate analysis. Eighty-eight percent of the subjects are correctly classified by CET as a single parameter. The results suggest that increased CET in the patients may reflect atherogenic alterations in TG metabolism and/or in lipid transfer protein activities despite normal fasting lipoprotein levels.
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Proteínas Portadoras/sangre , Ésteres del Colesterol/sangre , Glicoproteínas , Lípidos/sangre , Enfermedades Vasculares Periféricas/sangre , Anciano , Análisis de Varianza , Estudios de Casos y Controles , Proteínas de Transferencia de Ésteres de Colesterol , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Vasculares Periféricas/enzimología , Fosfatidilcolinas/sangre , Fosfolípidos/sangre , Esterol O-Aciltransferasa/sangreRESUMEN
OBJECTIVES: To evaluate the safety and potential efficacy of antithrombin III (AT III) in reducing mortality in patients with severe sepsis. DESIGN: Prospective, randomized, placebo-controlled, double-blind, phase II, multicenter, multinational clinical trial. SETTING: Seven academic medical center intensive care units (ICU) in Belgium, Denmark, the Netherlands, Norway and Sweden. PATIENTS: 42 patients with severe sepsis who received standard supportive care and antimicrobial therapy, in addition to the administration of AT III or placebo. INTERVENTIONS: Patients received either an intravenous loading dose of 3000 IU AT III followed by a maintenance dose of 1500 IU every 12 h for 5 days or equivalent amounts of placebo. MEASUREMENTS AND RESULTS: All patients were evaluated for safety and for 30-day all-cause mortality. CONCLUSIONS: The administration of AT III was safe and well-tolerated. It was followed by a 39 % reduction in 30-day all-cause mortality (NS). The reduction in mortality was accompanied by a considerably shorter stay in the ICU. Patients treated with AT III exhibited a better performance in overall severity of illness and organ failure scores (Acute Physiology and Chronic Health Evaluation II, multiple organ failure, organ system failure), which was noticeable soon after initiation of treatment. Patients treated with AT III demonstrated a better resolution of pre-existing organ failures and a lower incidence of new organ failures during the observation period. A meta-analysis comprising this and two other double-blind, placebo-controlled trials with AT III with a total of 122 patients suffering from severe sepsis confirms the positive trend. The results of the meta-analysis demonstrate a 22.9 % reduction in 30-day all-cause mortality in patients treated with AT III. Although still too small to be confirmative, the meta-analysis clearly points to the fact that a sufficiently powered phase III trial is warranted to prove whether AT III has a beneficial role in the treatment of severe sepsis.
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Antitrombina III/uso terapéutico , Sepsis/tratamiento farmacológico , APACHE , Anciano , Causas de Muerte , Método Doble Ciego , Esquema de Medicación , Femenino , Humanos , Infusiones Intravenosas , Tiempo de Internación/estadística & datos numéricos , Masculino , Persona de Mediana Edad , Insuficiencia Multiorgánica/etiología , Estudios Prospectivos , Sepsis/complicaciones , Sepsis/microbiología , Sepsis/mortalidad , Análisis de SupervivenciaRESUMEN
We evaluated the effect of C1 inhibitor (C1-inh), an inhibitor of the classical pathway of complement and the contact system, on the physiologic and inflammatory response in baboons suffering from lethal Escherichia coli sepsis. Five animals pretreated with 500 U/kg C1-inh (treatment group; n = 5), followed by a 9-h continuous infusion of 200 U/kg C1-inh subsequent to bacterial challenge, were compared with five controls receiving E. coli alone. Of the treatment group, one animal survived and another lived beyond 48 h, whereas all control animals died within 27 h. In four of five treated animals, less severe pathology was observed in various target organs. C1-inh administration did not prevent the hemodynamic or hematologic changes observed upon E. coli infusion. The activation of fibrinolysis and the development of disseminated intravascular coagulation were essentially unaffected by C1-inh. However, C1-inh supplementation significantly reduced decreases in plasma levels of factor XII and prekallikrein and abrogated the systemic appearance of C4b/c, indicating substantial inhibition of activation of the contact system and the classical complement pathway, respectively. Furthermore, treated animals displayed a reduced elaboration of various cytokines including TNF, IL-10, IL-6, and IL-8. Thus, the administration of C1-inh may have a beneficial but modest effect on the clinical course and outcome of severe sepsis in nonhuman primates. We suggest that activated complement and/or contact system proteases may, at least in part, contribute to the attendant manifestations of septic shock through an augmentation of the cytokine response.
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Proteínas Inactivadoras del Complemento 1/administración & dosificación , Infecciones por Escherichia coli/terapia , Choque Séptico/terapia , Animales , Degranulación de la Célula , Activación de Complemento , Citocinas/biosíntesis , Factor XII/metabolismo , Femenino , Fibrinólisis , Humanos , Masculino , Neutrófilos/fisiología , Papio , Precalicreína/metabolismo , Choque Séptico/fisiopatología , Trombina/metabolismoRESUMEN
Despite improvements in critical care medicine and the development and aggressive use of potent broad-spectrum anti-microbial agents, mortality due to severe sepsis has not changed during the recent years and still comes to 35% to 45%. For quite a long time our understanding of the pathophysiology of sepsis was mainly focused on endotoxin and proinflammatory cytokines like tumor necrosis factor or interleukin-1. Now it is generally accepted that many signs and symptoms of sepsis are not directly mediated by cytokines but are transmitted through other mediator systems. The coagulation system comes into play especially when the septic process progresses to malperfusion and organ failure. Antithrombin III is an important inhibitor of the intrinsic, extrinsic and common pathway of coagulation. Recently, evidence has been accumulating that there is an additional anti-inflammatory potential of the drug. Currently there are several clinical trials ongoing to investigate whether this effect is of clinical relevance in the treatment of patients with severe sepsis.
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Antitrombina III/uso terapéutico , Insuficiencia Multiorgánica/tratamiento farmacológico , Sepsis/tratamiento farmacológico , Inhibidores de Serina Proteinasa/uso terapéutico , Ensayos Clínicos como Asunto , Enfermedad Crítica , Humanos , Incidencia , Insuficiencia Multiorgánica/complicaciones , Prevalencia , Sepsis/complicaciones , Sepsis/epidemiologíaRESUMEN
BIBB 515 (1-(4-chlorobenzoyl)-4-((4-(2-oxazolin-2-yl) benzylidene))piperidine) is a potent and selective inhibitor of 2,3-oxidosqualene cyclase (OSC) [EC 5.4.99.7]. In rats and mice BIBB 515 inhibited OSC in vivo in a dose-dependent manner after 1, 3, and 5 h with ED50 values from 0.2 to 0.5 mg/kg (1 to 5 h) in rats and 0.36 (1 h) to 15.5 (3 h) and 33.3 (5 h) mg/kg in mice. Inhibition of [14C]acetate incorporation into sterols was found to parallel the effects on OSC when measured after 1 h (mice) or 3 h (rats). ED50 calculated were 0.9 mg/kg (mice) and 0.1 mg/kg (rats). Dose-dependent lipid-lowering activity was seen in normolipemic hamsters after 11 days treatment (-19% for total cholesterol and -32% for VLDL + LDL cholesterol at 55 mg/kg BIBB 515 per day) and in hyperlipemic hamsters after 25 days (-25% for total cholesterol and -59% for LDL-cholesterol at 148 mg/kg BIBB 515 per day). Calculation of kinetic parameters revealed no relevant differences between control and treatment groups in LDL clearance or fractional catabolic rates, but significant reductions of LDL production rates (-30% to -54%). Liver LDL receptor mRNA of the treated animals was not or only slightly increased. Liver VLDL secretion as measured by the Triton WR1339 method was reduced after BIBB 515 in rats and hamsters. It is concluded that the lipid-lowering effect of BIBB 515 is mainly the result of an inhibition of LDL production rather than due to an increase in LDL catabolism. OSC inhibitors may offer a novel approach for lipid-lowering therapy.
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Colesterol/biosíntesis , Inhibidores Enzimáticos/farmacología , Transferasas Intramoleculares , Isomerasas/antagonistas & inhibidores , Metabolismo de los Lípidos , Oxazoles/farmacología , Piperidinas/farmacología , Animales , Colesterol/sangre , Colesterol/metabolismo , Cricetinae , Inhibidores Enzimáticos/síntesis química , Hidroximetilglutaril-CoA Reductasas/genética , Hidroximetilglutaril-CoA Reductasas/metabolismo , Lípidos/sangre , Lipoproteínas LDL/metabolismo , Hígado/química , Hígado/metabolismo , Masculino , Mesocricetus , Ratones , Ratones Endogámicos , Piperidinas/síntesis química , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Ratas Wistar , Receptores de LDL/genética , Receptores de LDL/metabolismo , Escualeno/análogos & derivados , Escualeno/farmacología , Células Tumorales CultivadasRESUMEN
Within the cholesterol biosynthesis cascade, the enzyme 2,3-oxidosqualene cyclase [EC 5.4.99.7] is of special interest due to its dual function: cyclization of 2,3-monoepoxysqualene to lanosterol and 2,3;22,23-diepoxysqualene to oxylanosterol. Further determination of the significance of this enzyme for the intracellular cholesterol homeostasis was done with BIBX 79, a new potent, specific inhibitor of this enzyme. In HepG2 cells the effects of BIBX 79 on cholesterol biosynthesis, 2,3-oxidosqualene cyclase as well as HMG-CoA reductase activities were studied. BIBX 79 is a potent inhibitor of sterol biosynthesis in HepG2 cells (IC50 4 x 10(-9) M). No other enzyme within the cholesterol biosynthesis cascade was significantly inhibited as was evidenced by a radio HPLC detection system. In contrast to simvastatin, no direct interaction with HMG-CoA reductase was observed. When incubating HepG2 cells for 16 h with the HMG-CoA reductase inhibitor simvastatin (10(-6)-10(-10) M) HMG-CoA reductase activity was increased up to 180%. BIBX 79 did also affect HMG-CoA reductase activity under these conditions: in concentrations of BIBX 79 "> or =" 10(-9) "< or =" 10(-7) M, where a partial inhibition of 2,3-oxidosqualene cyclase is observed, HMG-CoA reductase activity was decreased. However, higher concentrations of BIBX 79 that totally blocked 2,3-oxidosqualene cyclase led to an increase in HMG-CoA reductase activity. This effect of BIBX 79 on HMG-CoA reductase is thought to be mainly mediated by oxysterols that are formed by the cyclization of 2,3;22,23-diepoxysqualene. 2,3;22,23-Diepoxysqualene is preferentially cyclized by the 2,3-oxidosqualene cyclase and, consequently, only high inhibitor concentrations will also block 2,3;22,23-diepoxysqualene cyclization. Thus, by partial blockade of this enzyme, both an inhibition of lanosterol and subsequently cholesterol formation as well as a concomitant effect on HMG-CoA reductase can be achieved. Both effects complement each other and lead to an effective control of cholesterol biosynthesis. It is therefore concluded that 2,3-oxidosqualene cyclase plays a crucial role in the regulation of intracellular cholesterol homeostasis. 2,3-Oxidosqualene cyclase inhibitors offer an attractive approach for novel lipid-lowering agents.
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Benzamidas/farmacología , Colesterol/biosíntesis , Ciclohexilaminas/farmacología , Inhibidores Enzimáticos/farmacología , Transferasas Intramoleculares , Isomerasas/antagonistas & inhibidores , Hígado/metabolismo , Compuestos Epoxi/metabolismo , Regulación Enzimológica de la Expresión Génica , Humanos , Hidroximetilglutaril-CoA Reductasas/biosíntesis , Hipolipemiantes/farmacología , Hígado/citología , Lovastatina/análogos & derivados , Lovastatina/farmacología , Simvastatina , Escualeno/análogos & derivados , Células Tumorales CultivadasRESUMEN
Capillary leak syndrome (CLS) is a severe complication after bone marrow transplantation (BMT). To investigate whether there is a pathogenetic role of the complement system, we monitored the levels of the terminal complement complex C5b-9 (TCC) and C3a-desArg as indicators of an activation of the complement system and the inhibitor of the classical pathway of the complement cascade, C1 inhibitor (C1-INH), in 48 bone marrow transplant recipients from 1 week before to 5 weeks after transplantation. Capillary leak syndrome developed in 7 out of 48 patients between days 1 and 12 after BMT. Complement activation as indicated by TCC levels was more pronounced in patients with CLS (n = 7) from day -8 to +28 (p < 0.05; day -1) and the elevation of TCC levels lasted longer in CLS patients (peak day 21) than in patients without this complication (peak day 7). Mean C3a-desArg levels were highest in patients with CLS reaching a peak at day 7. During the early posttransplant period a significant elevation of C1-INH levels (p < 0.01 and p < 0.05 respectively) compared with baseline levels (day -8) was found in patients with and without CLS, which was more pronounced in those patients with CLS (p < 0.05). Although we could not observe an absolute C1-INH deficiency as compared to healthy individuals our data support the presence of a relative deficiency of the inhibitor which might explain the reported beneficial effects of C1-INH substitution in BMT related CLS.
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Trasplante de Médula Ósea/efectos adversos , Permeabilidad Capilar , Proteínas Inactivadoras del Complemento 1/análisis , Complemento C3a/análisis , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , SíndromeRESUMEN
Activation of the complement and contact systems occur in patients with septic shock and is associated with a poor outcome. Activation of both systems is regulated by a common inhibitor, C1-esterase inhibitor (C1-Inh). Functional levels of C1-Inh are normal or slightly decreased in septic patients although this inhibitor is an acute phase protein. Moreover, an increased turn-over of C1-Inh in sepsis likely occurs since levels of proteolytically inactivated ("modified") C1-Inh are increased in this syndrome. One may therefore postulate that in sepsis there is a relative deficiency of C1-Inh. Here we will summarize our preliminary studies in 11 patients with septic shock, who received high doses of C1-Inh for up to 5 days. Activation of complement and contact systems also occurs in "a human model for septic shock" i.e., the vascular leak syndrome (VLS) induced by immunotherapy with the cytokine interleukin-2 (IL-2). The similarity between VLS and sepsis is not only reflected by similar patterns of complement and contact activation, but also by comparable hemodynamic and biochemical changes, and by the involvement of a number of other inflammatory mediators, such as the release of pro-inflammatory cytokines, and activation of coagulation and fibrinolysis and of neutrophils. Here we will also summarize our initial studies of the effect of C1-Inh administration to 6 patients with the VLS induced by IL-2. Our results indicate that high doses of C1-Inh can be safely administered to patients with septic shock or with the VLS, and may attenuate complement and contact activation in these conditions. Whether this therapy may reduce mortality and or morbidity of either syndrome has to be established by double-blind controlled studies.
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Permeabilidad Capilar/efectos de los fármacos , Proteínas Inactivadoras del Complemento 1/uso terapéutico , Interleucina-2/efectos adversos , Choque Séptico/tratamiento farmacológico , Coagulación Sanguínea/efectos de los fármacos , Activación de Complemento/efectos de los fármacos , Proteínas Inactivadoras del Complemento 1/química , Proteínas Inactivadoras del Complemento 1/farmacocinética , Humanos , Choque Séptico/fisiopatología , Relación Estructura-Actividad , SíndromeRESUMEN
Vascular-leak syndrome (VLS) is a common complication in the first 3 weeks after bone marrow transplantation (BMT). The patients present with weight gain, generalized edema, ascites, pericardial or pleural effusions, tachycardia, arterial hypotonia, and/or pre-renal failure. The aim of our study was to investigate the role of the complement system in VLS. The protein concentrations of C3 and C4 were studied by immunodiffusion, and total hemolytic complement activity was studied by assessment of CH50. C1 esterase inhibitor (C1 Inh), the major inhibitor of the classical pathway of complement, was assessed by a functional test. Activation of complement was assessed by C4d (a C4 activation product). Twelve patients were followed prospectively from start of conditioning therapy to day +21 after bone marrow transplantation. Eight of 12 patients did not develop VLS. These patients had an increase of C3 between day +9 and day +13 (range: 1.3- to 1.5-fold, median: 1.4-fold), C4 (range: 1.3- to 1.9-fold, median: 1.4-fold), CH50 (range: 1.3- to 1.6-fold, median: 1.4-fold), and C1 Inh (range: 1.2- to 1.5-fold, median: 1.3-fold). Four of 12 patients developed VLS. C1 Inh activity was decreased to 0.60- to 0.80-fold. This decrease began 2-6 days prior to clinical diagnosis of VLS (n = 3), or at onset of VLS (n = 1). Patients with VLS showed elevated C4d concentrations (up to 2.4 mg/dl, upper normal threshold value: 0.9 mg/dl). Patients with VLS reveal an activated state of the complement system which is accompanied by a reduced activity of C1 Inh. Insufficient control of complement activation may contribute to VLS in patients after BMT.
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Trasplante de Médula Ósea/efectos adversos , Proteínas Inactivadoras del Complemento 1/fisiología , Enfermedades Vasculares/metabolismo , Adolescente , Adulto , Peso Corporal , Niño , Preescolar , Ensayo de Actividad Hemolítica de Complemento , Femenino , Humanos , Masculino , Trasplante Autólogo , Trasplante Homólogo , Enfermedades Vasculares/etiología , Enfermedades Vasculares/fisiopatologíaRESUMEN
C1-inhibitor (C1-INH) is the major plasma inhibitor of the complement and contact systems. Activation of either system has been shown to occur in patients with septic shock and is associated with a poor outcome. Functional levels of C1-INH tend to be normal in septic patients although paradoxically this inhibitor is an acute phase protein. Moreover, levels of proteolytically inactivated C1-INH are increased in sepsis pointing to an increased turn-over. These observations suggest a relative deficiency of biologically active C1-INH in sepsis. Complement and contact activation have also been shown to occur in the vascular leak syndrome (VLS) induced by immunotherapy with the cytokine interleukin-2 (IL-2), which syndrome may be regarded as a human model for septic shock. The similarity between VLS and sepsis encompasses more than complement and contact activation since a number of other inflammatory mediators considered to play a role in the pathogenesis of septic shock, are also involved in the development of VLS. The role and the mechanisms of complement and contact activation in sepsis and in the VLS are reviewed in this paper. Initial results of intervention therapy with high doses of C1-INH in these syndromes are also reported. It is concluded that high doses of C1-INH can be safely administered to patients with septic shock or with the VLS and may attenuate complement and contact activation in these conditions. Double-blind controlled studies are needed to definitely proved these effects and to establish whether this treatment is able to reduce mortality and morbidity of these syndromes.