Evaluation of posterolateral lumbar fusion in sheep using mineral scaffolds seeded with cultured bone marrow cells.

The objective of this study is to investigate the efficacy of hybrid constructs in comparison to bone grafts (autograft and allograft) for posterolateral lumbar fusion (PLF) in sheep, instrumented with transpedicular screws and bars. Hybrid constructs using cultured bone marrow (BM) mesenchymal stem cells (MSCs) have shown promising results in several bone healing models. In particular, hybrid constructs made by calcium phosphate-enriched cells have had similar fusion rates to bone autografts in posterolateral lumbar fusion in sheep. In our study, four experimental spinal fusions in two animal groups were compared in sheep: autograft and allograft (reference group), hydroxyapatite scaffold, and hydroxyapatite scaffold seeded with cultured and osteoinduced bone marrow MSCs (hybrid construct). During the last three days of culture, dexamethasone (dex) and beta-glycerophosphate (ß-GP) were added to potentiate osteoinduction. The two experimental situations of each group were tested in the same spinal segment (L4-L5). Spinal fusion and bone formation were studied by clinical observation, X-ray, computed tomography (CT), histology, and histomorphometry. Lumbar fusion rates assessed by CT scan and histology were higher for autograft and allograft (70%) than for mineral scaffold alone (22%) and hybrid constructs (35%). The quantity of new bone formation was also higher for the reference group, quite similar in both (autograft and allograft). Although the hybrid scaffold group had a better fusion rate than the non-hybrid scaffold group, the histological analysis revealed no significant differences between them in terms of quantity of bone formation. The histology results suggested that mineral scaffolds were partly resorbed in an early phase, and included in callus tissues. Far from the callus area the hydroxyapatite alone did not generate bone around it, but the hybrid scaffold did. In nude mice, labeled cells were induced to differentiate in vivo and monitored by bioluminescence imaging (BLI). Although the cultured MSCs had osteogenic potential, their contribution to spinal fusion when seeded in mineral scaffolds, in the conditions disclosed here, remains uncertain probably due to callus interference with the scaffolds. At present, bone autografts are better than hybrid constructs for posterolateral lumbar fusion, but we should continue to seek better conditions for efficient tissue engineering.

Phospho-kinase profile of triple negative breast cancer and androgen receptor signaling.

BACKGROUND: The androgen receptor (AR) plays a central role in the oncogenesis of different tumors, as is the case in prostate cancer. In triple negative breast cancer (TNBC) a gene expression classification has described different subgroups including a luminal androgen subtype. The AR can be controlled by several mechanisms like the activation of membrane tyrosine kinases and downstream signaling pathways. However little is known in TNBC about how the AR is modulated by these mechanisms and the potential therapeutic strategists to inhibit its expression. METHODS: We used human samples to evaluate the expression of AR by western-blot and phospho-proteomic kinase arrays that recognize membrane tyrosine kinase receptors and downstream mediators. Western-blots in human cell lines were carried out to analyze the expression and activation of individual proteins. Drugs against these kinases in different conditions were used to measure the expression of the androgen receptor. PCR experiments were performed to assess changes in the AR gene after therapeutic modulation of these pathways. RESULTS: AR is present in a subset of TNBC and its expression correlates with activated membrane receptor kinases-EGFR and PDGFRß in human samples and cell lines. Inhibition of the PI3K/mTOR pathway in TNBC cell lines decreased notably the expression of the AR. Concomitant administration of the anti-androgen bicalutamide with the EGFR, PDGFRß and Erk1/2 inhibitors, decreased the amount of AR compared to each agent given alone, and had an additive anti-proliferative effect. Administration of dihydrotestosterone augmented the expression of AR that was not modified by the inhibition of the PI3K/mTOR or Erk1/2 pathways. AR expression was posttranscriptionally regulated by PI3K or Erk1/2 inhibition. CONCLUSION: Our results describe the expression of the AR in TNBC as a druggable target and further suggest the combination of bicalutamide with inhibitors of EGFR, PDGFRß or Erk1/2 for future development.

Activation of the PI3K/mTOR/AKT pathway and survival in solid tumors: systematic review and meta-analysis.

BACKGROUND: Aberrations in the phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR)/AKT pathway are common in solid tumors. Numerous drugs have been developed to target different components of this pathway. However the prognostic value of these aberrations is unclear. METHODS: PubMed was searched for studies evaluating the association between activation of the PI3K/mTOR/AKT pathway (defined as PI3K mutation [PIK3CA], lack of phosphatase and tensin homolog [PTEN] expression by immunohistochemistry or western-blot or increased expression/activation of downstream components of the pathway by immunohistochemistry) with overall survival (OS) in solid tumors. Published data were extracted and computed into odds ratios (OR) for death at 5 years. Data were pooled using the Mantel-Haenszel random-effect model. RESULTS: Analysis included 17 studies. Activation of the PI3K/mTOR/AKT pathway was associated with significantly worse 5-year survival (OR:2.12, 95% confidence intervals 1.42-3.16, p<0.001). Loss of PTEN expression and increased expression/activation of downstream components were associated with worse survival. No association between PIK3CA mutations and survival was observed. Differences between methods for assessing activation of the PI3K/mTOR/AKT pathway were statistically significant (p = 0.04). There was no difference in the effect of up-regulation of the pathway on survival between different cancer sites (p = 0.13). CONCLUSION: Activation of the PI3K/AKT/mTOR pathway, especially if measured by loss of PTEN expression or increased expression/activation of downstream components is associated with poor survival. PIK3CA mutational status is not associated with adverse outcome, challenging its value as a biomarker of patient outcome or as a stratification factor for patients treated with agents acting on the PI3K/AKT/mTOR pathway.

Pharmacological Characterization of the Mechanisms Involved in Delayed Calcium Deregulation in SH-SY5Y Cells Challenged with Methadone.

Previously, we have shown that SH-SY5Y cells exposed to high concentrations of methadone died due to a necrotic-like cell death mechanism related to delayed calcium deregulation (DCD). In this study, we show that, in terms of their Ca(2+) responses to 0.5 mM methadone, SH-SY5Y cells can be pooled into four different groups. In a broad pharmacological survey, the relevance of different Ca(2+)-related mechanisms on methadone-induced DCD was investigated including extracellular calcium, L-type Ca(2+) channels, µ-opioid receptor, mitochondrial inner membrane potential, mitochondrial ATP synthesis, mitochondrial Ca(2+)/2Na(+)-exchanger, reactive oxygen species, and mitochondrial permeability transition. Only those compounds targeting mitochondria such as oligomycin, FCCP, CGP 37157, and cyclosporine A were able to amend methadone-induced Ca(2+) dyshomeostasis suggesting that methadone induces DCD by modulating the ability of mitochondria to handle Ca(2+). Consistently, mitochondria became dramatically shorter and rounder in the presence of methadone. Furthermore, analysis of oxygen uptake by isolated rat liver mitochondria suggested that methadone affected mitochondrial Ca(2+) uptake in a respiratory substrate-dependent way. We conclude that methadone causes failure of intracellular Ca(2+) homeostasis, and this effect is associated with morphological and functional changes of mitochondria. Likely, this mechanism contributes to degenerative side effects associated with methadone treatment.

Minocycline exerts uncoupling and inhibiting effects on mitochondrial respiration through adenine nucleotide translocase inhibition.

The present study was aimed to provide a better understanding of the mitochondria-targeted actions of minocycline (MC), a second-generation tetracycline which has cytoprotective effects. Although the specific mechanisms underlying its activity remained elusive, considerable amounts of data indicated mitochondria as the primary pharmacological target of MC. Previous reports have shown that MC affects the oxygen-uptake rate by isolated mitochondria in different respiratory states. Here, we report on the effect of MC, in the range 50-200µM, on mitochondrial respiration. State 3 respiration titration with carboxyatractyloside revealed that MC inhibits the adenine nucleotide translocase. Furthermore, we analyze MC channel-forming capacity in the lipid membrane bilayer. Our results confirmed the crucial role of Δψ and showed a dependence on Ca(2+) for MC to have an effect on mitochondria. Our data also indicated that outer and inner mitochondrial membranes contribute differently to this effect, involving the presence of Δψ (the inner membrane) and VDAC (the outer membrane). Data from three isosmotic media indicate that MC does not increase the permeability of the inner membrane to protons or potassium. In addition, by using mitoplasts and ruthenium red, we showed that Ca(2+) uptake is not involved in the MC effect, suggesting involvement of VDAC in the MC interaction with the outer membrane. Our data contribute to unravel the mechanisms behind the mitochondria-targeted activity of the cytoprotective drug MC.

Methadone induces necrotic-like cell death in SH-SY5Y cells by an impairment of mitochondrial ATP synthesis.

Methadone is a widely used therapeutic opioid in narcotic addiction and neuropathic pain syndromes. Oncologists regularly use methadone as a long-lasting analgesic. Recently it has also been proposed as a promising agent in leukemia therapy, especially when conventional therapies are not effective. Nevertheless, numerous reports indicate a negative impact on human cognition with chronic exposure to opiates. Thus, clarification of methadone toxicity is required. In SH-SY5Y cells we found that high concentrations of methadone were required to induce cell death. Methadone-induced cell death seems to be related to necrotic processes rather than typical apoptosis. Cell cultures challenged with methadone presented alterations in mitochondrial outer membrane permeability. A mechanism that involves Bax translocation to the mitochondria was observed, accompanied with cytochrome c release. Furthermore, no participation of known protein regulators of apoptosis such as Bcl-X(L) and p53 was observed. Interestingly, methadone-induced cell death took place by a caspases-independent pathway; perhaps due to its ability to induce a drastic depletion in cellular ATP levels. Therefore, we studied the effect of methadone on isolated rat liver mitochondria. We observed that methadone caused mitochondrial uncoupling, coinciding with the ionophoric properties of methadone, but did not cause swelling of the organelles. Overall, the effects observed for cells in the presence of supratherapeutic doses of methadone may result from a "bioenergetic crisis." A decreased level of cellular energy may predispose cells to necrotic-like cell death.

Respuesta inflamatoria durante los procesos de isquemia: moléculas de adhesión e inmunomodulación / Inflammatory response during ischaemic processes: adhesion molecules and immunomodulation

Introducción. Tras la isquemia cerebral se produce la muerte necrótica de las células afectadas por la ausencia de oxígeno y glucosa, especialmente de las neuronas. Esta necrosis desencadena la activación del sistema inmune y el inicio de la respuesta inflamatoria. El sistema nervioso central cuenta con células inflamatorias innatas como la microglía y los macrófagos, que poseen una función importante en la recepción y propagación de señales inflamatorias. Desarrollo. La respuesta inflamatoria se caracteriza por la expresión de mediadores inflamatorios y la invasión de células inflamatorias circulantes. El paso de los leucocitos a través del endotelio implica dos etapas coordinadas en el tiempo: la adhesión y la subsiguiente migración transendotelial. Por ello, las moléculas de adhesión en leucocitos y células endoteliales, como son las selectinas, las sialomucinas, la superfamilia de las inmunoglobulinas y las integrinas, constituyen moléculas clave que contribuyen al daño cerebral. Sin embargo, dicha respuesta precisa eliminar los restos celulares tanto necróticos como apoptóticos para iniciar los posibles procesos de reparación y plasticidad cerebral. Por tanto, la respuesta inflamatoria es una respuesta coordinada, y tras la activación de la inflamación se desencadena también una respuesta inmunosupresora y antiinflamatoria. Conclusiones. La inflamación se ha asociado a un aumento en el daño cerebral en pacientes con infarto cerebral, aunque es necesaria para activar los mecanismos de reparación. Por ello resulta preciso un estricto control de la respuesta inflamatoria después del infarto cerebral para reducir el daño del tejido afectado sin la inhibición de los mecanismos de reparación (AU)

Introduction. After cerebral ischemia, necrotic cell death occurs specially for neurons, mainly due to the privation of oxygen and glucose. Cell necrosis triggers the activation of the immune system followed by an inflammatory response. This reaction is characterized by the activation of astrocytes and microglia together with the infiltration of peripheral immune cells. Development. Both, microglia and inflammatory cells, including circulating peripheral inflammatory cells, get activated and release a plethora of inflammatory mediators, cytokines, chemokines, etc. Such released factors induce the overexpression of adhesion molecules, increasing the blood brain barrier permeability, thus favoring even more inflammatory cell infiltration. In the end, this contributes to increase brain damage. Inflammatory response is nevertheless necessary in order to eliminate cellular debris from both apoptotic and necrotic cells. It seems to be also implicated in the initiation of certain mechanisms responsible for brain repair and plasticity. As a result, the inflammatory response is a coordinated effort. Activation of inflammation triggers an immunosuppressant and anti-inflammatory response. A high rate of infections in patients suffering from stroke, together with increased serum levels of anti-inflammatory molecules in these patients, support this statement. The anti-inflammatory response could be interpreted as the organism attempting to control the heightened inflammatory response that occurs after cerebral ischemia. On the other hand, following an ischemic event, there are several new cerebral epitopes that get exposed to the immune system, which would never have been exposed under normal physiological conditions. Conclusion. Therefore immunosuppression after an ischemic accident hinders the development of auto-immune responses (AU)

[Inflammatory response during ischaemic processes: adhesion molecules and immunomodulation]. / Respuesta inflamatoria durante los procesos de isquemia: moléculas de adhesión e inmunomodulación.

INTRODUCTION: After cerebral ischemia, necrotic cell death occurs specially for neurons, mainly due to the deprivation of oxygen and glucose. Cell necrosis triggers the activation of the immune system followed by an inflammatory response. This reaction is characterized by the activation of astrocytes and microglia together with the infiltration of peripheral immune cells. DEVELOPMENT: Both, microglia and inflammatory cells, including circulating peripheral inflammatory cells, get activated and release a plethora of inflammatory mediators, cytokines, chemokines, etc. Such released factors induce the overexpression of adhesion molecules, increasing the blood brain barrier permeability, thus favoring even more inflammatory cell infiltration. In the end, this contributes to increase brain damage. Inflammatory response is nevertheless necessary in order to eliminate cellular debris from both apoptotic and necrotic cells. It seems to be also implicated in the initiation of certain mechanisms responsible for brain repair and plasticity. As a result, the inflammatory response is a coordinated effort. Activation of inflammation triggers an immunosuppressant and anti-inflammatory response. A high rate of infections in patients suffering from stroke, together with increased serum levels of anti-inflammatory molecules in these patients, support this statement. The anti-inflammatory response could be interpreted as the organism attempting to control the heightened inflammatory response that occurs after cerebral ischemia. On the other hand, following an ischemic event, there are several new cerebral epitopes that get exposed to the immune system, which would never have been exposed under normal physiological conditions. CONCLUSION: Therefore immunosuppression after an ischemic accident hinders the development of auto-immune responses.

[Inflammation as a therapeutic agent in cerebral infarction: cellular inflammatory response and inflammatory mediators]. / La inflamación como agente terapéutico en el infarto cerebral: respuesta inflamatoria celular y mediadores inflamatorios.

INTRODUCTION: The immune central nervous system (CNS) innate immune cells including microglia and macrophages play integral roles in receiving and propagating inflammatory signals. Inflammation is generally a beneficial response of an organism to infection but, when prolonged or inappropriate, it can be detrimental. Neuronal loss in acute (e.g. stroke and head injury) and chronic (e.g. multiple sclerosis and Alzheimer's disease) CNS diseases has been associated with inflammatory processes systemically and in the brain. DEVELOPMENT: Herein we review the processes that participate in the activation of the immune system and the starting of inflammatory response after stroke, where neuronal necrotic cell death has been described. We addressed the relevance of the innate inflammatory cells that are on the CNS, as microglia and macrophages, which have an important role in receiving and spreading inflammatory signals. In addition, the inflammatory response is characterized by an increase in the levels of expression of inflammatory mediators, which regulate adhesion molecules, and increase the permeability of the blood-brain barrier. It has also been described that inflammation promotes the rapid over-expression and activation of a variety of genes, and it has been postulated that transcription factors should be studied for their potential use in therapeutics and repair. Transcriptional activation can be a double-edged sword since depending on the individual transcription factor it can induce the expression of either neuroprotective or neurotoxic genes. CONCLUSION: In summary, a better understanding of the different molecules mediating the immune response will allow the design of new pharmacological tools that could improve stroke treatment.

Action of recombinant human BMP-2 on fracture healing in rabbits is dependent on the mechanical environment.

The utility of recombinant human bone morphogenetic protein-2 (rhBMP-2) in inducing bone formation in fractures of bone is well known. However, the influence of the mechanical environment on the actions of rhBMP-2 on fracture healing is not clear. An experimental model of fractures of the tibia in rabbits was developed and utilized to investigate the role of mechanical environment on rhBMP-2 action. A 1 mm osteotomy gap was stabilized by either a low- or high-stiffness fixator (LSF or HSF, respectively), and local treatment with rhBMP-2 in an absorbable collagen sponge (ACS) was evaluated. The results of the investigation were analysed by both histomorphometry and biomechanics. The LSF caused an increase in mineralized periosteal callus compared to HSF, the rhBMP-2 in ACS accelerated fracture healing only in the LSF group but not in the HSF group. The area of mineralized tissue in interfragmentary callus was determined by fixation stiffness and not by BMP treatment. rhBMP-2 caused higher bone resorption in the endosteal callus during the late stages of fracture healing, but these histological differences did not affect the mechanical properties. Biomechanical evaluation showed only differences at 3 weeks between LSF-rhBMP-2 and LSF-ACS. The bending and torsional properties were higher in the rhBMP-2/ACS group compared to ACS alone at 3 weeks.

La inflamación como agente terapéutico en el infarto cerebral: respuesta inflamatoria celular y mediadores inflamatorios / Inflammation as a therapeutic agent in cerebral infarction: cellular inflammatory response and inflammatory mediators

Introducción. El sistema nervioso central (SNC) posee células inflamatorias innatas como la microglía y los macrófagos, los cuales tienen una función importante en la recepción y propagación de señales inflamatorias. Recientemente se ha postulado que el sistema inmune y el proceso inflamatorio participan de forma activa en la pérdida neuronal descrita en enfermedades del SNC agudas (infarto cerebral) y crónicas (esclerosis múltiple, enfermedad de Alzheimer). Desarrollo. Se revisan los procesos que conducen a la activación del sistema inmune y el inicio de la respuesta inflamatoria tras la isquemia cerebral, donde se produce la muerte necrótica de las células afectadas, especialmente de las neuronas. Así se profundiza en el papel de las células inflamatorias innatas de las que dispone el SNC, como la microglía y los macrófagos, las cuales poseen una función importante en la recepción y propagación de señales inflamatorias. Además, la respuesta inflamatoria se caracteriza por un incremento en los niveles de expresión de mediadores inflamatorios, que sobrerregulan las moléculas de adhesión y aumentan la permeabilidad de la barrera hematoencefálica. Se ha descrito también que la inflamación promueve la rápida sobreexpresión y activación de una variedad de genes, habiéndose postulado a los factores de transcripción como posibles dianas sobre las que actuar en la reparación y la terapéutica. Sin embargo, la activación transcripcional puede verse como una espada de doble filo porque la transcripción individual de factores puede inducir tanto a genes neuroprotectores como neurotóxicos. Conclusión. Un mayor conocimiento de las distintas moléculas involucradas en la respuesta inflamatoria permitiría el diseño de nuevas aproximaciones farmacológicas que contribuirían a la mejora en el tratamiento de la isquemia cerebral (AU)

Introduction. The immune central nervous system (CNS) innate immune cells including microglia and macrophages play integral roles in receiving and propagating inflammatory signals. Inflammation is generally a beneficial response of an organism to infection but, when prolonged or inappropriate, it can be detrimental. Neuronal loss in acute (e.g. stroke and head injury) and chronic (e.g. multiple sclerosis and Alzheimer’s disease) CNS diseases has been associated with inflammatory processes systemically and in the brain. Development. Herein we review the processes that participate in the activation of the immune system and the starting of inflammatory response after stroke, where neuronal necrotic cell death has been described. We addressed the relevance of the innate inflammatory cells that are on the CNS, as microglia and macrophages, which have an important role inreceiving and spreading inflammatory signals. In addition, the inflammatory response is characterized by an increase in the levels of expression of inflammatory mediators, which regulate adhesion molecules, and increase the permeability of the blood-brain barrier. It has also been described that inflammation promotes the rapid over-expression and activation of a variety of genes, and it has been postulated that transcription factors should be studied for their potential use in therapeutics and repair. Transcriptional activation can be a double-edged sword since depending on the individual transcription factor it can induce the expression of either neuroprotective or neurotoxic genes. Conclusion. In summary, a better understanding of the different molecules mediating the immune response will allow the design of new pharmacological tools that could improve stroke treatment (AU)