Convergencia de vías de señalización en un modelo de apoptosis

La sepsis es un evento inflamatorio generalizado del organismo inducido por un daño causado generalmente por un agente infeccioso. El patógeno más frecuentemente asociado con esta entidad es el Staphylococcus aureus, responsable de la inducción de apoptosis en células endoteliales debida a la producción de ceramida. Se ha descrito el efecto protector de la proteína C activada (PCA) en sepsis y su relación con la disminución de la apoptosis de las células endoteliales. En este trabajo se analizó la activación de las quinasas AKT, ASK1, SAPK/JNK y p38 en un modelo de apoptosis endotelial usando las técnicas de Western Blotting y ELISA. Las células endoteliales (EA.hy926), se trataron con C2-ceramida (130μM) en presencia de inhibidores químicos de cada una de estas quinasas y PCA. La supervivencia de las células en presencia de inhibidores químicos y PCA fue evaluada por medio de ensayos de activación de las caspasas 3, 7 y 9, que verificaban la muerte celular por apoptosis. Los resultados evidencian que la ceramida reduce la activación de AKT y aumenta la activación de las quinasas ASK, SAPK/JNK y p38, en tanto que PCA ejerce el efecto contrario. Adicionalmente se encontró que la tiorredoxina incrementa la activación/fosforilación de AKT, mientras que la quinasa p38 induce la defosforilación de AKT.

Adherencia a las guías de reanimación temprana dirigida por metas, en un hospital de Bogotá, Colombia

Introducción: El manejo temprano de los pacientes con sepsis severa y choque séptico en los servicios de urgencias bajo la “terapia temprana dirigida por metas”, propuesto por Rivers en su guía “Surviving Sepsis Campain”, parece relacionarce con la disminución de la mortalidad en los primeras 28 días posteriores a la atención médica. El presente estudio busca medir la adherencia a estas recomendaciones en un servicio de urgencias de un hospital de cuarto nivel. Metodología: Mediante un estudio observacional analítico de corte transversal, fueron revisadas las historias clínicas de un grupo de pacientes con sepsis severa y choque séptico, que ingresaron en el año 2013 al servicio de urgencias de un hospital de cuarto nivel de Bogotá, Colombia, con el fin de determinar la proporción de pacientes que recibió reanimación temprana guiada por metas de acuerdo a la guía internacional. Resultados: Se evaluaron 3000 registros clínicos, de los cuales fueron incluídos 130 pacientes. 15.4% recibió manejo de acuerdo a las guías internacionales de reanimación temprana. La mortalidad por sepsis severa y choque séptico fue del 10.7%. La mortalidad en pacientes atendidos de acuerdo a las guías fue del 15% comparada y del 10% en los no adherentes (p > 0.05). Conclusiones: El presente estudio muestra cifras bajas de adherencia a las recomendaciones internacionales propuestas por Rivers. Se deben realizar campañas de sensibilización y capacitación al personal médico y paramédico de los servicios de urgencias con el fin de mejorar la supervivencia en este grupo de pacientes.

The importance of human FcyRI in mediating protection to malaria

The success of passive immunization suggests that antibody-based therapies will be effective at controlling malaria. We describe the development of fully human antibodies specific for Plasmodium falciparum by antibody repertoire cloning from phage display libraries generated from immune Gambian adults. Although these novel reagents bind with strong affinity to malaria parasites, it remains unclear if in vitro assays are predictive of functional immunity in humans, due to the lack of suitable animal models permissive for P. falciparum. A potentially useful solution described herein allows the antimalarial efficacy of human antibodies to be determined using rodent malaria parasites transgenic for P. falciparum antigens in mice also transgenic for human Fc-receptors. These human IgG1s cured animals of an otherwise lethal malaria infection, and protection was crucially dependent on human FcγRI. This important finding documents the capacity of FcγRI to mediate potent antimalaria immunity and supports the development of FcγRI-directed therapy for human malaria.

Symptoms and distress in children with advanced cancer: prospective patient-reported outcomes from the PediQUEST Study

PURPOSE: Thousands of children are living with advanced cancer; yet patient-reported outcomes (PROs) have rarely been used to describe their experiences. We aimed to describe symptom distress in 104 children age 2 years or older with advanced cancer enrolled onto the Pediatric Quality of Life and Evaluation of Symptoms Technology (PediQUEST) Study (multisite clinical trial evaluating an electronic PRO system).

METHODS: Symptom data were collected using age- and respondent-adapted versions of the PediQUEST Memorial Symptom Assessment Scale (PQ-MSAS) at most once per week. Clinical and treatment data were obtained from medical records. Individual symptom scores were dichotomized into high/low distress. Determinants of PQ-MSAS scores were explored using linear mixed-effects models.

RESULTS: During 9 months of follow-up, PQ-MSAS was administered 920 times: 459 times in teens (99% self-report), 249 times in children ages 7 to 12 years (96% child/parent report), and 212 times in those ages 2 to 6 years (parent reports). Common symptoms included pain (48%), fatigue (46%), drowsiness (39%), and irritability (37%); most scores indicated high distress. Among the 73 PQ-MSAS surveys administered in the last 12 weeks of life, pain was highly prevalent (62%; 58% with high distress). Being female, having a brain tumor, experiencing recent disease progression, and receiving moderate- or high-intensity cancer-directed therapy in the prior 10 days were associated with worse PQ-MSAS scores. In the final 12 weeks of life, receiving mild cancer-directed therapy was associated with improved psychological PQ-MSAS scores.

CONCLUSION: Children with advanced cancer experience high symptom distress. Strategies to promote intensive symptom management are indicated, especially with disease progression or administration of intensive treatments.

Autoimmune thyroid disease as a risk factor for angioedema in patients with chronic idiopathic urticaria: a case-control study

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Positive fluid balance is associated with reduced survival in critically ill patients with cancer

Background There are no studies that describe the impact of the cumulative fluid balance on the outcomes of cancer patients admitted to intensive care units ICUs. The aim of our study was to evaluate the relationship between fluid balance and clinical outcomes in these patients. Method One hundred twenty-two cancer patients were prospectively evaluated for survival during a 30-day period. Univariate (Chi-square, t-test, MannWhitney) and multiple logistic regression analyses were used to identify the admission parameters associated with mortality. Results The mean cumulative fluid balance was significantly higher in non-survivors than in survivors [1675?ml/24?h (4712921) vs. 887?ml/24?h (104557), P?=?0.017]. We used the area under the curve and the intersection of the sensibility and specificity curves to define a cumulative fluid balance value of 1100?ml/24?h. This value was used in the univariate model. In the multivariate model, the following variables were significantly associated with mortality in cancer patients: the Acute Physiology and Chronic Health Evaluation II score at admission [Odds ratio (OR) 1.15; 95% confidence interval (CI) (1.051.26), P?=?0.003], the Lung Injury Score at admission [OR 2.23; 95% CI (1.293.87), P?=?0.004] and a positive fluid balance higher than 1100?ml/24?h at ICU [OR 5.14; 95% CI (1.4518.24), P?=?0.011]. Conclusion A cumulative positive fluid balance higher than 1100?ml/24?h was independently associated with mortality in patients with cancer. These findings highlight the importance of improving the evaluation of these patients' volemic state and indicate that defined goals should be used to guide fluid therapy.

Multicentre study on peri- and postoperative central venous oxygen saturation in high-risk surgical patients

Introduction Low central venous oxygen saturation (ScvO2) has been associated with increased risk of postoperative complications in high-risk surgery. Whether this association is centre-specific or more generalisable is not known. The aim of this study was to assess the association between peri- and postoperative ScvO2 and outcome in high-risk surgical patients in a multicentre setting. Methods Three large European university hospitals (two in Finland, one in Switzerland) participated. In 60 patients with intra-abdominal surgery lasting more than 90 minutes, the presence of at least two of Shoemaker's criteria, and ASA (American Society of Anesthesiologists) class greater than 2, ScvO2 was determined preoperatively and at two hour intervals during the operation until 12 hours postoperatively. Hospital length of stay (LOS) mortality, and predefined postoperative complications were recorded. Results The age of the patients was 72 ± 10 years (mean ± standard deviation), and simplified acute physiology score (SAPS II) was 32 ± 12. Hospital LOS was 10.5 (8 to 14) days, and 28-day hospital mortality was 10.0%. Preoperative ScvO2 decreased from 77% ± 10% to 70% ± 11% (p < 0.001) immediately after surgery and remained unchanged 12 hours later. A total of 67 postoperative complications were recorded in 32 patients. After multivariate analysis, mean ScvO2 value (odds ratio [OR] 1.23 [95% confidence interval (CI) 1.01 to 1.50], p = 0.037), hospital LOS (OR 0.75 [95% CI 0.59 to 0.94], p = 0.012), and SAPS II (OR 0.90 [95% CI 0.82 to 0.99], p = 0.029) were independently associated with postoperative complications. The optimal value of mean ScvO2 to discriminate between patients who did or did not develop complications was 73% (sensitivity 72%, specificity 61%). Conclusion Low ScvO2 perioperatively is related to increased risk of postoperative complications in high-risk surgery. This warrants trials with goal-directed therapy using ScvO2 as a target in high-risk surgery patients.

Membranöse Glomerulopathie-eine Autoimmunerkrankung

Membranous nephropathy is one of the most common glomerular diseases and leading causes of nephrotic syndrome in Caucasian adults. Known as a clinico-pathologic entity for over 50 years, it is defined by thickening of the glomerular capillary membrane with subepithelial immuncomplexes. Secondary forms (e. g. hepatitis B, autoimmune disease or medication-induced) are distinguished from idiopathic forms. Despite spontaneous remissions in about 30 % of cases, one third of idiopathic forms progress to end-stage renal disease after 10 years. Seminal research progress of the last decade has allowed the identification of autoantibodies directed against podocytary elements leading to secondary damage to the filtration barrier. The so-called idiopathic membranous nephropathy has thus become a prototype of autoimmune disease. The autoantibodies detectable in 70 - 80 % of cases of idiopathic membranous nephropathy are directed against the M-type phospholipase A2-receptor on the podocyte membrane and correlate with disease activity. These epochal findings influence on diagnostic and therapeutic strategies establishing a rationale for the use of B cell-directed therapy on top of optimal supportive therapy.

The transcriptional repressor Delta EF1 controls resistance to the EGFR inhibitor erlotinib in human HNSCC lines

Epidermal Growth Factor Receptor (EGFR) overexpression occurs in about 90% of Head and Neck Squamous Cell Carcinoma (HNSCC) cases. Aberrant EGFR signaling has been implicated in the malignant features of HNSCC. Thus, EGFR appears to be a logical therapeutic target with increased tumor specificity for the treatment of HNSCC. Erlotinib, a small molecule tyrosine kinase inhibitor, specifically inhibits aberrant EGFR signaling in HNSCC. Only a minority of HNSCC patients were able to derive a substantial clinical benefit from erlotinib. ^ This dissertation identifies Epithelial to Mesenchymal Transition (EMT) as the biological marker that distinguishes EGFR-dependent (erlotinib-sensitive) tumors from the EGFR-independent (erlotinib-resistant) tumors. This will allow us to prospectively identify the patients who are most likely to benefit from EGFR-directed therapy. More importantly, our data identifies the transcriptional repressor DeltaEF1 as the mesenchymal marker that controls EMT phenotype and resistance to erlotinib in human HNSCC lines. si-RNA mediated knockdown of DeltaEF1 in the erlotinib-resistant lines resulted in reversal of the mesenchymal phenotype to an epithelial phenotype and significant increase in sensitivity to erlotinib. ^ DeltaEF1 represses the expression of the epithelial markers by recruiting HDACs to chromatin. This observation allows us to translate our findings into clinical application. To test whether the transcriptional repression by DeltaEF1 underlines the mechanism responsible for erlotinib resistance, erlotinib-resistant lines were treated with an HDAC inhibitor (SAHA) followed by erlotinib. This resulted in a synergistic effect and substantial increase in sensitivity to erlotinib in the resistant cell lines. Thus, combining an HDAC inhibitor with erlotinib represents a novel promising pharmacologic strategy for reversing resistance to erlotinib in HNSCC patients. ^

BIOLOGICAL MECHANISMS AND CLINICAL IMPLICATIONS OF BCR-ABL-INDUCED MITOCHONDRIAL OXIDATIVE STRESS AND CELL SURVIVAL IN CHRONIC MYELOID LEUKEMIA

Chronic myeloid leukemia (CML), a myeloproliferative disorder, represents approximately 15-20% of all adult leukemia. The development of CML is clearly linked to the constitutively active protein-tyrosine kinase BCR-ABL, which is encoded by BCR-ABL fusion gene as the result of chromosome 9/22 translocation (Philadelphia chromosome). Previous studies have demonstrated that oxidative stress-associated genetic, metabolic and biological alterations contribute to CML cell survival and drug refractory. Mitochondria and NAD(P)H oxidase (NOX) are the major sources of BCR-ABL-induced cellular reactive oxygen species (ROS) production. However, it is still unknown how CML cells maintain the altered redox status, while escaping from the persistent oxidative stress-induced cell death. Therefore, elucidation of the mechanisms by which CML cells cope with oxidative stress will provide new insights into CML leukemogenesis. The major goal of this study is to identify the survival factors protecting CML cells against oxidative stress and develop novel therapeutic strategies to overcome drug resistance. Several experimental models were used to test CML cell redox status and cellular sensitivity to oxidative stress, including BCR-ABL inducible cell lines, BCR-ABL stably transformed cell lines and BCR-ABL-expressing CML blast crisis cells with differential BCL-XL/BCL-2 expressions. Additionally, an artificial CML cell model with heterogenic BCL-XL/BCL-2 expression was established to assess the correlation between differential survival factor expression patterns and cell sensitivity to Imatinib and oxidative stress. In this study, BCL-XL and GSH have been identified as the major survival factors responsive to BCR-ABL-promoted cellular oxidative stress and play a dominant role in regulating the threshold of oxidative stress-induced apoptosis. Cell survival factors BCL-XL and BCL-2 differentially protect mitochondria under oxidative stress. BCL-XL is an essential survival factor in preventing excessive ROS-induced cell death while BCL-2 seems to play a relatively minor role. Furthermore, the redox modulating reagent β-phenethyl isothiocyanate (PEITC) has been found to efficiently deplete GSH and induce potent cell killing effects in drug-resistant CML cells. Combination of PEITC with BCL-XL/BCL2 inhibitor ABT737 or suppression of BCL-XL by BCR-ABL inhibitor Gleevec dramatically sensitizes CML cells to apoptosis. These results have suggested that elevation of BCL-XL and cellular GSH are important for the development of CML, and that redox-directed therapy is worthy of further clinical investigations in CML.

Microglia as therapeutic targets in retinal degeneration: role of translocator protein (18 κDa) (TSPO) and minocycline.

Microglia are the resident immune cells of the central nervous system (CNS) and play an important role in innate immune defense as well as tissue homeostasis. Chronic microglial reactivity, microgliosis, is a general hallmark of inflammatory and degenerative diseases that affect the CNS, including the retina. There is increasing evidence that chronic microgliosis is more than just a bystander effect, but rather actively contributes to progression of degeneration through processes such as toxic nitric oxide (NO) production and even phagocytosis of stressed but viable photoreceptors. Therefore immunmodulation of microglia presents a possible therapeutic strategy for retinal degenerations. Notably, the expression of the mitochondrial translocator protein 18 (κDa) (TSPO) is highly elevated in reactive microglia as seen in several neuroinflammatory diseases such as Alzheimer’s disease, Parkinson’s disease and multiple sclerosis. Therefore it is used as a gliosis biomarker in the brain. Moreover TSPO ligands show potent effects in resolving neuroinflammatory brain disorders. However, TSPO expression in the eye had not been investigated before. Further, it was unknown whether TSPO ligands’ potent immunomodulatory effects could be used to treat retinal degenerations. To fill this gap, the study aimed to analyze whether TSPO is also a potential biomarker for degenerative processes in the retina. Moreover the thesis attempted to determine whether a specific TSPO ligand, XBD173, might modulate microglial reactivity and is a potent therapeutic, to treat retinal degenerative diseases. The findings revealed that TSPO is strongly upregulated in microglial cells of retinoschisin-deficient (RS1-/y) mice, a model of inherited retinal degeneration and in a murine light damage model. A co-localization of TSPO and microglia was furthermore detectable in human retinal sections, indicating a potential role for TSPO as a biomarker for retinal degenerations. In vitro assays showed that the TSPO ligand XBD173 effectively inhibited features of microglial activation such as morphological transformation into reactive phagocytes and enhanced expression of pro-inflammatory cytokines. XBD173 also reduced microglial migration and proliferation and reduced their neurotoxic potential on photoreceptor cells. In two independent mouse models of light-induced retinal degeneration, the treatment with XBD173 reduced accumulation of amoeboid, reactive microglia in the outer retina and attenuated degenerative processes, indicated by a nearly preserved photoreceptor layer. A further question addressed in this thesis was whether minocycline, an antibiotic with additional anti-inflammatory properties is able to reduce microglial neurotoxicity and to protect the retina from degeneration. Minocycline administration dampened microglial pro-inflammatory gene expression, NO production and neurotoxicity on photoreceptors. Interestingly, in addition to its immunomodulatory effect, minocycline also increased the viability of photoreceptors in a direct manner. In the light damage model, minocycline administration counter-acted microglial activation and blocked retinal degeneration. Taken together these results identified TSPO as a biomarker for microglial reactivity and as therapeutic target in the retina. Targeting TSPO with XBD173 was able to reverse microglial reactivity and could prevent degenerative processes in the retina. In addition, the study showed that the antibiotic minocycline effectively counter-regulates microgliosis and light-induced retinal degeneration. Considering that microgliosis is a major contributing factor for retinal degenerative disorders, this thesis supports the concept of a microglia-directed therapy to treat retinal degeneration.

Liver-directed lentiviral gene therapy in a dog model of hemophilia B

We investigated the efficacy of liver-directed gene therapy using lentiviral vectors in a large animal model of hemophilia B and evaluated the risk of insertional mutagenesis in tumor-prone mouse models. We showed that gene therapy using lentiviral vectors targeting the expression of a canine factor IX transgene in hepatocytes was well tolerated and provided a stable long-term production of coagulation factor IX in dogs with hemophilia B. By exploiting three different mouse models designed to amplify the consequences of insertional mutagenesis, we showed that no genotoxicity was detected with these lentiviral vectors. Our findings suggest that lentiviral vectors may be an attractive candidate for gene therapy targeted to the liver and may be potentially useful for the treatment of hemophilia.

Clinical potential of gene-directed enzyme prodrug therapy to improve radiation therapy in prostate cancer patients

Despite the advances in prostate cancer diagnosis and treatment, current therapies are not curative in a significant proportion of patients. Gene-directed enzyme prodrug therapy (GDEPT), when combined with radiation therapy, could improve the outcome of treatment for prostate cancer, the second leading cause of cancer death in the western world. GDEPT involves the introduction of a therapeutic transgene, which can be targeted to the tumour cells. A prodrug is administered systemically and is converted to its toxic form only in those cells containing the transgene, resulting in cell kill. This review will discuss the clinical trials which have investigated the potential of GDEPT at various stages of prostate cancer progression. The advantages of using GDEPT in combination with radiotherapy will be examined, as well as some of the recent advances which enhance the potential utility of GDEPT.

New prodrugs derived from 6-aminodopamine and 4-aminophenol as candidates for melanocyte-directed enzyme prodrug therapy (MDEPT)

Two novel tyrosinase mediated drug delivery pathways have been investigated for the selective delivery of cytotoxic units to melanocytes from urea and thiourea prodrugs. The synthesis of these prodrugs is reported, as well as oximetry data that illustrate that the targets are substrates for tyrosinase. The stability of each of the prodrugs in (i) phosphate buffer and (ii) bovine serum is discussed, and the urea prodrugs are identified as lead candidates for further studies. Finally, HPLC studies and preliminary cytotoxicity studies in a melanotic and an amelanotic cell line, that illustrate the feasibility of the approach, are presented.