Francisco Javier García-Criado

Tacrolimus (FK506) down-regulates free radical tissue levels, serum cytokines, and neutrophil infiltration after severe liver ischemia

BACKGROUND Liver ischemia and reperfusion injury is associated with activation of multiple inflammatory pathways, including free radicals, cytokines, and neutrophil-mediated tissue damage among others. Tacrolimus (FK506) has shown important regulatory effects on some inflammatory pathways, such as cytokines, neutrophils, and adhesion molecules. In this study, we explored a new potential protective mechanism for tacrolimus in the liver inflammatory response after ischemia and reperfusion, specifically its effect on liver tissue free radicals. METHODS Total hepatic ischemia was produced in the rat for 90 min with an extracorporeal portosystemic shunt. Animals (n=96) were divided into four groups: group 1 comprised normal rats for reference values; group 2 comprised sham operated rats; in group 3, ischemic control rats received only the vehicle; and the experimental treatment group, group 4, received tacrolimus at a dose of 0.3 mg/kg, 4 hr before ischemia. Animal survival was followed up to 7 days. Liver function tests were performed and liver tissue free radicals and myeloperoxidase, serum cytokines (interleukin 1, tumor necrosis factor-alpha), and liver histology were measured 4 hr after reperfusion. RESULTS Seven-day survival was significantly improved from only 20% in the control group to 55% in the tacrolimus group (P<0.01). Liver function tests, histology, and myeloperoxidase tissue values were significantly improved (P<0.05) with tacrolimus pretreatment. Furthermore, a significant (P<0.05) down-regulation of serum cytokines and liver tissue free radicals was observed. CONCLUSIONS These data indicate a new and different protective mechanism for FK506 in regard to its ability to down-regulate free radical levels in livers subjected to severe ischemia and reperfusion. Tacrolimus, also confirmed to be a potent suppressor of the cytokine response, specifically interleukin 1 and tumor necrosis, decreased neutrophil tissue migration as well.

Protective effect of exogenous nitric oxide on the renal function and inflammatory response in a model of ischemia-reperfusion.

BACKGROUND Tissue subjected to a period of ischemia undergoes morphological and functional damage that increases during the reperfusion phase. The aim of the present work was to assess the possible improvement induced by exogenous administration of nitric oxide (NO) on renal injury and inflammatory reaction in an experimental animal model of renal ischemia-reperfusion (I-R). METHODS Ischemia was achieved by ligation of the left arteria and vein for 60 min, followed first by contralateral nephrectomy and then reestablishment of blood flow. Molsidomine, used as an NO donor, was administered by systemic injection 30 min before reperfusion. The effect of molsidomine was compared with the effect of hydralazine, a non-NO donor hypotensive agent. RESULTS Treatment with molsidomine improved the renal dysfunction (increase in plasma creatinine and urea levels) caused by I-R. Moreover, molsidomine blunted the enhanced production of proinflammatory cytokines (tumor necrosis factor [TNF]-alpha and interleukin [IL] 1alpha), the increase in tissular levels of superoxide anions and oxygen free radical scavengers, and the neutrophilic infiltration observed in the ischemic kidney. One hundred percent survival was achieved in the group of animals treated with the NO donor, whereas the groups of animals undergoing I-R that did not receive molsidomine showed a 40% mortality from the second day after reperfusion. CONCLUSIONS The present work demonstrated that systemic treatment with an NO donor before reperfusion improved renal function and diminished inflammatory responses in a kidney subjected to an I-R process.

Expression of MALT1 oncogene in hematopoietic stem/progenitor cells recapitulates the pathogenesis of human lymphoma in mice

Chromosomal translocations involving the MALT1 gene are hallmarks of mucosa-associated lymphoid tissue (MALT) lymphoma. To date, targeting these translocations to mouse B cells has failed to reproduce human disease. Here, we induced MALT1 expression in mouse Sca1+Lin− hematopoietic stem/progenitor cells, which showed NF-κB activation and early lymphoid priming, being selectively skewed toward B-cell differentiation. These cells accumulated in extranodal tissues and gave rise to clonal tumors recapitulating the principal clinical, biological, and molecular genetic features of MALT lymphoma. Deletion of p53 gene accelerated tumor onset and induced transformation of MALT lymphoma to activated B-cell diffuse large-cell lymphoma (ABC-DLBCL). Treatment of MALT1-induced lymphomas with a specific inhibitor of MALT1 proteolytic activity decreased cell viability, indicating that endogenous Malt1 signaling was required for tumor cell survival. Our study shows that human-like lymphomas can be modeled in mice by targeting MALT1 expression to hematopoietic stem/progenitor cells, demonstrating the oncogenic role of MALT1 in lymphomagenesis. Furthermore, this work establishes a molecular link between MALT lymphoma and ABC-DLBCL, and provides mouse models to test MALT1 inhibitors. Finally, our results suggest that hematopoietic stem/progenitor cells may be involved in the pathogenesis of human mature B-cell lymphomas.

The comparative abilities of propofol and sevoflurane to modulate inflammation and oxidative stress in the kidney after aortic cross-clamping.

BACKGROUND:Propofol has been reported to provide protection against ischemia–reperfusion injury. Nuclear transcription factor kappa B (NF&kgr;B) plays a key role in oxidative stress and the inflammatory response during ischemia–reperfusion. We compared the effect of propofol with sevoflurane on kidney NF&kgr;B expression and systemic inflammatory responses induced by aortic clamping. METHODS:Twenty piglets were divided into four groups: sham surgery group with propofol (group SP, n = 5); sham group with sevoflurane (group SS, n = 5); and suprarenal clamping for 30 min with aorta–aortic bypass under propofol (group CP, n = 5) or sevoflurane (group CS, n = 5) anesthesia. Propofol was administered at 4 mg · kg−1 · h−1 IV and sevoflurane given at 1.5% inspiratory concentration. Peripheral blood and kidney biopsies were taken before the start of surgery, 15 min after unclamping the aorta, 24, 48, 72 h, and 7 days after surgery. Plasma creatinine, myeloperoxidase, tumor necrosis factor-&agr;, interleukin 1-&bgr;; and kidney superoxide anion and superoxidase dismutase were measured. The expression of inducible nitric oxide synthase and renal tissue NF&kgr;B was measured using Western blotting. RESULTS:Compared with the CS group, animals in the CP group had lower concentrations of myeloperoxidase, tumor necrosis factor-&agr;, interleukin 1&bgr;, superoxide anion, superoxidase dismutase (P < 0.05) from 24 to 72 h after surgery and diminished NF&kgr;B expression and inducible nitric oxide synthase activity (P < 0.05) at 48 and 72 h after surgery, respectively. CONCLUSIONS:Compared with sevoflurane, propofol administration during suprarenal aortic clamping and unclamping led to modulation of markers of inflammation and decreased NF&kgr;B expression.

Cancer as a reprogramming-like disease: implications in tumor development and treatment.

Cancer is a clonal malignant disease originated in a single cell and characterized by the accumulation of partially differentiated cells that are phenotypically reminiscent of normal stages of differentiation. Given the fact that human cancer is diagnosed at later stages and cannot be monitored during its natural evolution, the origin of tumors has been a subject of continuing discussion. Animal models provide a means to determine the identity of the cell-of-origin leading to malignancy and to develop new treatments. Recent findings in mice have shown that cancer stem cells could arise through a reprogramming-like mechanism, suggesting that genetic lesions that initiate the cancer process might be dispensable for tumor progression and maintenance. This review addresses the impact of these results toward a better understanding of carcinogenesis and proposes research avenues for tackling these issues in the future.

Intrarenal Administration of Molsidomine, a Molecule Releasing Nitric Oxide, Reduces Renal Ischemia-Reperfusion Injury in Rats

Ischemia reperfusion (I‐R)‐induced renal damage is reduced by systemic administration of the NO‐dependent vasodilator molsidomine. The aim of this study was to estimate the effect of direct intrarenal molsidomine administration on renal dysfunction and inflammatory reaction after experimental I‐R in rats, in order to assess only renal NO effects and to obviate its systemic hemodynamic action. Ischemia was induced by renal pedicle ligation (60 min) followed by reperfusion and contralateral nephrectomy. Molsidomine (4 mg/kg) was infused into the renal artery 15 min before reperfusion and its effects were compared with those of the NO‐independent vasodilator hydralazine (2 mg/kg). Survival rates after 7 days were 100% in the sham‐operated group and 75% in the I‐R rats. Molsidomine treatment almost completely prevented the I‐R‐induced renal dysfunction, and survival reached 100%. Molsidomine prevented an I‐R‐induced increase in superoxide anion and reduced plasma levels of pro‐inflammatory cytokines (TNF‐α, IL‐1β and IFN‐γ), whereas it enhanced anti‐inflammatory cytokines (IL‐6 and IL‐10). Inflammatory cell infiltration and cell‐adhesion molecules (ICAM‐1, PECAM‐1, VCAM‐1 and P‐selectin) were lower in the molsidomine‐treated kidneys than in the untreated animals. All these protective effects were not observed after hydralazine administration. In conclusion, intrarenal administration of molsidomine before reperfusion improved renal function and decreased inflammatory responses after I‐R.

Laboratory investigation: Effects of propofol on the systemic inflammatory response during aortic surgery

PurposeA laboratory investigation was undertaken to assess the effects of propofol on renal function, through modulation of the systemic inflammatory response, in anin vivo experimental model of aortic surgery in comparison with sevoflurane.MethodsTwenty young male piglets were anesthetized with either propofol 4 mg·kg-1·hr-1 (n = 10) or sevoflurane 1.5% end-tidal concentration (n = 10). Animals were subjected to aorta-aortic bypass with suprarenal aortic clamping for 30 min. At specific intervals (basal -before the start of surgery; reperfusion 15 min after unclamping the aorta; at 24, 48 and 72 hr after surgery, and on the seventh day after surgery) the levels of the following were determined: plasma creatinine, renal myeloperoxidase, tumour necrosis factor-α, interleukin 1-ß, and interferon-γ; kidney superoxide anion and its detoxifying enzyme superoxidase dismutase, kidney malondialdehyde and the activity of inducible nitric oxide synthase. Seven days after surgery, the animals were anesthetized using the described techniques, and after blood withdrawal and kidney sampling they were sacrificed.ResultsIn comparison with sevoflurane, propofol was associated with a lower concentration of plasma creatinine (P < 0.05) together with lower concentrations of myeloperoxidase, tumour necrosis factor-α, interleukin 1-ß, interferon-γ, super-oxide anion and superoxidase dismutase, malondialdehyde and inducible nitric oxide synthase (P < 0.05).ConclusionIn an experimental model of aortic reconstructive surgery, and compared with sevoflurane, propofol anesthesia is associated with less neutrophil infiltration, lower plasma proinflammatory cytokine levels, lower production of oxygen free radicals, less lipid peroxidation, and reduced inducible nitric oxide synthase activity. These observations suggest a possible renal protective effect of propofol in this surgical setting.AbstractObjectifUn essai en laboratoire a été entrepris pour évaluer les effets du propofol sur la fonction rénale, à travers la modulation de la réaction inflammatoire généralisée, chez un modèle expérimental in vivo de chirurgie aortique et en comparaison avec le sévoflurane.MéthodeVingt jeunes porcelets ont été anesthésiés avec 4 mg·kg1·h-1 de propofol (n = 10) ou de sévoflurane à une concentration télé-expiratoire de 1,5 % (n = 10). Ils ont subi un pontage aorto-aortique avec clampage aortique pendant 30 min. À des moments spécifiques (au départ — avant le début de l’opération ; pendant la reperfusion 15 min après le déclampage de l’aorte ; à 24, 48 et 72 h après l’opération et au septième jour postopératoire), les niveaux suivants ont été déterminés : la créatinine plasmatique, la myéloperoxydase rénale, le facteur-α nécrosant tumoral, l’interleukine 1-ß et l’interféron-γ ; l’anion de superoxyde rénal et son enzyme de détoxification superoxydase dismutase, la malondialdéhyde rénale et l’activité de l’oxyde nitrique synthase inductible. Sept jours après l’opération, les animaux ont été anesthésiés selon les techniques décrites et, après le retrait du sang et la prise d’un échantillon rénal, ont été sacrifiés.RésultatsComparé au sévoflurane, le propofol a été associé à une plus faible concentration plasmatique de créatinine, (P < 0,05) et à de plus faibles concentrations de myéloperoxydase, de facteur-α nécrosant tumoral, d’interleukine 1-ß, d’interféron-γ, d’anion de superoxyde et de superoxyde dismutase, de malondial-déhyde et d’oxyde nitrique synthase inductible (P < 0,05).ConclusionPour un modèle expérimental de reconstruction aortique, et comparé à l’anesthésie au sévoflurane, l’anesthésie au propofol est associée à moins d’infiltration de neutrophiles, à des niveaux plasmatiques inférieurs de cytokine pro-inflammatoire, à une plus faible production de radicaux libres d’oxygène, à moins de peroxydation lipidique et à une activité réduite de l’oxyde nitrique synthase inductible. Ces observations indiquent un effet rénal protecteur possible du propofol dans ce contexte chirurgical.

Infection Exposure Is a Causal Factor in B-cell Precursor Acute Lymphoblastic Leukemia as a Result of Pax5-Inherited Susceptibility.

UNLABELLED Earlier in the past century, infections were regarded as the most likely cause of childhood B-cell precursor acute lymphoblastic leukemia (pB-ALL). However, there is a lack of relevant biologic evidence supporting this hypothesis. We present in vivo genetic evidence mechanistically connecting inherited susceptibility to pB-ALL and postnatal infections by showing that pB-ALL was initiated in Pax5 heterozygous mice only when they were exposed to common pathogens. Strikingly, these murine pB-ALLs closely resemble the human disease. Tumor exome sequencing revealed activating somatic, nonsynonymous mutations of Jak3 as a second hit. Transplantation experiments and deep sequencing suggest that inactivating mutations in Pax5 promote leukemogenesis by creating an aberrant progenitor compartment that is susceptible to malignant transformation through accumulation of secondary Jak3 mutations. Thus, treatment of Pax5(+/-) leukemic cells with specific JAK1/3 inhibitors resulted in increased apoptosis. These results uncover the causal role of infection in pB-ALL development. SIGNIFICANCE These results demonstrate that delayed infection exposure is a causal factor in pB-ALL. Therefore, these findings have critical implications for the understanding of the pathogenesis of leukemia and for the development of novel therapies for this disease.

Germinal centre protein HGAL promotes lymphoid hyperplasia and amyloidosis via BCR-mediated Syk activation

The human germinal centre associated lymphoma (HGAL) gene is specifically expressed in germinal centre B-lymphocytes and germinal centre-derived B-cell lymphomas, but its function is largely unknown. Here we demonstrate that HGAL directly binds Syk in B-cells, increases its kinase activity upon B-cell receptor stimulation and leads to enhanced activation of Syk downstream effectors. To further investigate these findings in vivo, HGAL transgenic mice were generated. Starting from 12 months of age these mice developed polyclonal B-cell lymphoid hyperplasia, hypergammaglobulinemia and systemic reactive AA amyloidosis, leading to shortened survival. The lymphoid hyperplasia in the HGAL transgenic mice are likely attributable to enhanced B-cell receptor signalling as shown by increased Syk phosphorylation, ex vivo B-cell proliferation and increased RhoA activation. Overall, our study shows for the first time that the germinal centre protein HGAL regulates B-cell receptor signalling in B-lymphocytes which, without appropriate control, may lead to B-cell lymphoproliferation.

Factores de riesgo de fracaso de la corrección quirúrgica de la incontinencia urinaria de esfuerzo mediante cinta suburetral transobturatriz

OBJECTIVE To identify risk factors leading to treatment failure in a sample of 302 women with stress urinary incontinence (SUI) treated by transobturator vaginal tape (TOT) with a medium follow-up of 4 years (range 1-6). MATERIAL AND METHODS A population based cohort study with prospectively data from 302 women, aged 41-81 years underwent TOT between April 2003-November 2010. Data were collected by validated questionnaire on urinary incontinence, the International Consultation on Incontinence Questionnaire - Short Form (ICIQ-SF), and clinical data-records. Continence was achieved in 262 (Group A) and 40 continued with incontinence (Group B). We investigated the relationship between age, SUI evolution time, type and number of childbirths (eutocic, dystocic, nulliparous, multiparous status) and medical and/or surgical backgrounds. The ICIQ-SF questionnaire was used to describe whether the surgery outcomes were successful or not. RESULTS Group A were younger (p=0.0001), had less SUI evolution time (p=0.017); more eutocic childbirths (p=0.000018). Group B had more dystocic childbirth (p=0.022), previous tension free vaginal tape (TVT) or TOT (p=0.03.), antidepressant-anxiolytic drugs (p=0.003), antihypertensive drugs (p=0.0005), type 1 diabetes (p=0.02), arterial hypertension (p=0.0007), respiratory diseases (p=0.025). Differences were not found with regard to nulliparous (p=0.701), multiparous status (p=0.42), obesity (p=0.18), intestinal disorders (p=0.59), oophorectomy (p=0.19), caesarean (p=0.17), prolapse surgery (p=0.29), hysterectomy (p=0.57), allergies (p=0.48), arthritis (p=0.22), arthrosis (p=0.44), depression (p=0.74), type 2 diabetes (p=0.44), smoking patterns (p=0.28), fibromyalgia (p=0.47). CONCLUSIONS Elderly women, with long evolution SUI, dystocic delivery, previous TVT or TOT appear as independent risk factors associated to TOT failure. These factors may make the indication of another surgical approach recommendable.