FDG-PET Intra-tratamiento como valor pronóstico en el tratamiento del linfoma Hodgkin

Introducción: La utilización de regímenes de tratamiento más individualizados requiere de mejores sistemas de estratificación temprana en Linfoma Hodgkin (LH). El estudio Tomografía por Emisión de Positrones utilizando 2-[18F] fluoro-2-deoxi-Dglucosa (FDG-PET) intra-tratamiento podría jugar un rol muy importante en esta evaluación. Objetivo: Determinar el valor pronóstico del FDG-PET intra-tratamiento en pacientes con LH para predecir sobrevida libre de progresión y sobrevida global. Material y método: El estudio fue llevado a cabo en el Servicio de Hematología del Hospital Central de Mendoza incluyendo pacientes con diagnóstico de LH confirmados por histología. De acuerdo al estadio y sitio de presentación, los pacientes recibieron quimioterapia sola o la combinación de radioterapia y quimioterapia, con el uso del esquema ABVD (adriamicina, bleomicina, vinblastina y dacarbazina) como protocolo estándar. Los estudios FDG-PET fueron practicados como parte de la evaluación intra-tratamiento y a la finalización. Resultados: En total fueron evaluados 8 pacientes, Sexo: F/M: 4/4, Edad: 18-58 años (Mediana: 29 años), Estadios: IIB:1, IIIA:2, IIIB:1, IVA:1, IVB:3, regiones nodales: 2-10 (Mediana:4), compromiso extranodal: 4/8, síntomas B: 5/8, enfermedad bulky 2/8 . Subtipos: Escleronodular: 6/8, Celularidad mixta: 1/8, Depleción linfocítica: 1/8. IPS: 1: 3/8 2: 3/8 3: 1/8 4: 0/8 ≥ 5: 1/8. Tratamientos: ABVD x 6: 6/8, ABVD x 6 + Radioterapia: 2/8. PET intermedio: 8/8 negativos (6/8 PET 3, 2/8 PET 2). PET final: 7/8 PET negativo, 1/8 PET positivo. Recaída: 1/8 (10° mes). Seguimiento: 11-37 meses (mediana de 24 meses). Discusión y Conclusiones: Al momento actual el FDG-PET intra-tratamiento demostró tener un importante valor predictivo negativo dado que todos los pacientes, menos uno, se encuentran en remisión completa sin progresión de enfermedad. Resta aún determinar el rol que esta herramienta pueda tener en el futuro en la terapia adaptada al riesgo de pacientes con LH.

Estado funcional y mortalidad en pacientes neoplásicos hospitalizados

Objetivos: Analizar el estado funcional y su relación con morbimortalidad en pacientes con neoplasias internados en Cínica Médica. Material y métodos: Estudio descriptivo, protocolizado y observacional. Se analizaron variables clínicas, estado funcional, situación anímica y morbimortalidad en pacientes oncológicos hospitalizados y se compararon pacientes con Índice de Karnofsky <40 puntos (grupo A) y >40 puntos (grupo B). Los datos fueron analizados en EPI Info 6.04. Informe de los primeros 3 meses. Resultados: En el período de estudio, ingresaron 66 pacientes con neoplasias, 21 (31.8%) en A, con Karnofsky promedio de 25 puntos (DS±12.09) y 45 (68.2%) en B, con Karnofsky promedio de 77 puntos (DS±16.65). El 77.3% presentó tumores sólidos y el 22.7% hematológicos y las neoplasias más frecuentes fueron del tracto gastrointestinal (19.6%), mama (12.1%), pulmón (9.1%) y primario oculto (7.6%). El estadio tumoral IV fue el más frecuente en ambos grupos (89.5% de A y 88.9% de B)(pNS). La edad media en A fue de 59.57 (DS±13.71) y 52.48 años (DS±15.65) en B (pNS) y el género masculino fue más frecuente en A (66.7 y 44.4% respectivamente) (p<0.05). La permanencia media fue de 17.57 en A (DS±20.84) y de 13.53 días (DS±16.29) en B (pNS). La evaluación de Actividades Básicas de la Vida Diaria [0.81 (DS±1.25) vs 4.57 puntos (DS±1.15)] y Actividades Instrumentales [0.57 (DS±0.74) vs 4 puntos (DS±1.37)] fue superior en B (p<0.05) y no hubo diferencias en la comorbilidad (85.7 vs 82.2%)(pNS). Las infecciones (52.4 vs 26.7%), causa social (38.1 vs 4.4%), complicaciones neoplásicas (81 vs 51.1%) y dolor (81 vs 51.1%) fueron los motivos de internación más frecuentes en A (p<0.05). Los pacientes de A recibieron con mayor frecuencia cuidados paliativos (90.5 vs46.7%) y quimioterapia (90.5 vs 46.7%)(p<0.05), sin diferencias en radioterapia (23.8 vs 13.3%) y cirugía (33.3 vs 33.3%)(pNS). No hubo diferencias entre ambos grupos en la presencia de depresión clínica (69.9 vs 53.3%) y pérdida de peso (86.4 vs 84.2%)(pNS). El síndrome confusional (85.7 vs 11.1%), postración (61.9 vs 6.7%) y escaras (23.8 vs 4.4%) fueron más frecuentes en A (p<0.05). La mortalidad hospitalaria fue 52.4% en A y 8.9% en B (p<0.05). Conclusiones: El grado de estado funcional evaluado por Karnofsky menor de 40 puntos se asoció significativamente a: mayor mortalidad, uso de quimioterapia, cuidados paliativos, internación por infecciones, dolor y complicaciones neoplásicas y presencia de síndrome confusional, postración y escaras de decúbito (p<0.05).

Enseñanza de auto-cuidado en pacientes oncológicos

Esta tesis surge del deseo de hacer algo útil, de poder ayudar de alguna forma a los pacientes oncológicos que son los que necesitan una luz de esperanza en su vida y del interés de la educación y de la enseñanza del auto-cuidado desde el momento que empiezan los tratamientos quimioterapéuticos. La enfermedad oncológica es compleja, puede revestir gravedad y se hace más llevadera y mejor si el paciente sabe como es el manejo de los efectos adversos para su auto-cuidado, día tras día la atención de los pacientes oncológicos es llevada a cabo por un equipo multidisciplinario incluyendo la enfermería como pilar fundamental, ofreciendo compromiso y dedicación y la guía para lograr una buena calidad de vida en el paciente. A la falta de conocimientos sobre su etiología, se suma la incertidumbre sobre su futuro, asociada al dolor y la posibilidad inminente de la muerte. Ante el tratamiento, como el de la quimioterapia, es importante que el paciente construya una relación satisfactoria con el personal que lo atiende para poder evacuar sus dudas, como así también el involucrar a la familia. Para el paciente el hecho de familiarizarse con las prácticas del cuidado y auto-cuidado en su propio hogar es de vital importancia. Contar con el apoyo del equipo multidisciplinario que lo atiende, saber que se evacuaran sus dudas, que se brindara información en forma clara y concisa, lo hace sentir que no está solo y que no es tratado de forma diferente. El presente estudio será un canal para detectar las debilidades y fortalezas del centro oncológico. Y será de gran importancia para el equipo de salud, no solo para favorecer a la recuperación del paciente sino también para su reinserción en la sociedad brindándole mejor calidad de vida con los conocimientos de su enfermedad y contribuir al auto-cuidado del mismo.

Influencia de un programa de ejercicio aeróbico en la calidad de vida de pacientes afectadas por cáncer de mama = Influence of an aerobic exercise program on breast cancer patients’ quality of life

INTRODUCCIÓN Actualmente las supervivientes de cáncer de mama viven durante más tiempo. Sin embargo, los tratamientos utilizados presentan importantes efectos secundarios que afectan y marcan su calidad de vida. Numerosos estudios han mostrado que el ejercicio es una herramienta apta, segura y efectiva reduciendo algunos de estos efectos secundarios y, en suma, mejorando la calidad de vida de estas pacientes, aspecto que presenta al ejercicio físico como una intervención integral para ellas. Por el contrario, se ha observado que las supervivientes de cáncer de mama reducen la cantidad de ejercicio que realizan después de dichos tratamientos. Por ello, el objetivo de este proyecto es examinar los efectos de un programa integral de ejercicio en la calidad de vida y la cantidad de ejercicio físico que realizan las pacientes con cáncer de mama en su tiempo, tras finalizar sus tratamientos. MATERIAL Y MÉTODOS Se diseñó un Ensayo Clínico Aleatorizado. Noventa pacientes diagnosticadas de cáncer de mama en estadios tempranos que habían terminado sus tratamientos de radioterapia y quimioterapia recientemente, fueron reclutadas por la Universidad Politécnica de Madrid, desde enero de 2013 hasta junio de 2014. Las pacientes fueron aleatorizadas tras las mediciones iniciales al grupo control (tratamientos habituales) o grupo intervención, durante tres meses. La intervención consistió en 24 clases de ejercicio combinando práctica aeróbica y de fuerza con el fin de reducir los efectos secundarios de dichos tratamientos. La calidad de vida, la cantidad de ejercicio físico realizado en tiempo de ocio, VO2max, la fuerza, la movilidad articular del hombro, la fatiga, la depresión y la ansiedad fueron medidos al inicio y después de los tres meses en todos los pacientes. RESULTADOS Un total de 89 pacientes con una media de 49.06±8.75 de edad fueron finalmente analizadas. El grupo intervención (n=44) mostraron significativamente mejores resultados en calidad de vida (p=0.0001; d=0.85), cantidad de ejercicio en tiempo de ocio (p=0.0001; d=2.77), en variables de la composición corporal, en variables físicas y en variables psicológicas comparado con el grupo control (n=45). Además, se observó una correlación significativa entre la calidad de vida y el ejercicio realizado en tiempo de ocio en el grupo intervención (r= 0.58; p=0.001), que no fue patente en el grupo control. Se observaron cambios significativos en el grupo de intervención relativos a la composición corporal, con aumento de la masa muscular (p=0.001) y reducción de la masa grasa (p=0.0001). Tanto las variables físicas como psicológicas también mostraron diferencias significativas a favor al grupo de intervención en las comparaciones entre grupos. CONCLUSIONES Según estos resultados, un programa de ejercicio físico específico es una intervención integral que mejora los hábitos y la calidad de vida de las supervivientes de cáncer de mama, lo que reduce determinados efectos secundarios de los tratamientos y aumenta la salud física y psicológica general de estas mujeres. Este tipo de intervenciones pude ser una herramienta barata y efectiva para ofrecer a los pacientes, integrada en los tratamientos habituales. ABSTRACT INTRODUCTION It is well known that breast cancer survivors are living longer. However, breast cancer treatments present serious side effects, which could affect breast cancer survivors’ (BCS) health and quality of life (QoL). Exercise has been presented as a feasible, safe and effective tool in reducing some of these side effects and to improve survivors’ QoL, acting as an integrative treatment for them, although it has been observed that BCS reduce their leisure time exercise (LTE) levels. Therefore, the aim of this study was to examine the effects of an integrative exercise program in QoL and LTE in BCS after the completion of their adjuvant treatment. MATERIAL AND METHODS A randomized controlled trial (RCT) was designed. Ninety patients diagnosed with an early stage of breast cancer and who recently finished chemotherapy and radiotherapy treatments were recruited by the Technical University of Madrid from January 2013 to June 2014. Patients were randomized after baseline assessments to the intervention group (IG) or to the control group (CG) (usual care) for three months. The Intervention consisted in 24 supervised exercise classes, combining aerobic and resistance exercises in order to reduce the most common side effects of the treatments. QoL, LTE, body composition, VO2max, strength, shoulder range of motion, fatigue, depression and self-esteem were measured in all the patients at baseline and after three months. RESULTS A total of 89 patients aged 49.06±8.75 years were finally assessed. IG (n=44) showed significant better results in QoL (p=0.0001; d=0.85), LTE (p=0.0001; d=2.77), in body composition, in the physical variable and in psychological outcomes, compared with the CG (n=45). In addition, a correlation between QoL and LTE (r= 0.58; p=0.001) was found in the IG, while CG did not show this correlation. Significant changes in body composition were observed in the group comparisons, especially in lean mass (p=0.001) and body fat mass (p= 0.0001). Positive changes were also observed in the physical and psychological variables in comparisons between groups. CONCLUSIONS These results suggest that this exercise program may be an integrative intervention, which is able to improve QoL and LTE levels in breast cancer survivors, reducing breast cancer side effects of treatments and improving their physical and psychological general health. Exercise may be an effective and inexpensive strategy to be included in patients integrative care.

QUALIDADE DE VIDA E ESTRATÉGIAS DE ENFRENTAMENTO DE MULHERES COM E SEM LINFEDEMA APÓS CÂNCER DE MAMA

O linfedema no membro superior é uma complicação inerente ao tratamento de câncer de mama. Caracterizado pelo aumento do volume do membro, leva às limitações físicas e funcionais, e impacto negativo no âmbito psicológico e social. O objetivo deste estudo foi investigar a qualidade de vida e seus domínios, as estratégias de enfrentamento frente ao câncer de mama, e a correlação entre essas variáveis. Este estudo foi realizado em um centro de saúde dedicado às mulheres, por quatro meses. Os instrumentos de avaliação foram: questionário de caracterização geral e específico do câncer de mama, perimetria dos membros superiores; questionários de qualidade de vida da Organização Européia de Pesquisa e Tratamento do Câncer, EORTC QLQ-30 e BR-23; e Inventário de Estratégias de Coping. Foram entrevistadas 82 mulheres, idade média de 57,4 anos (DV12,3), submetidas a tratamento cirúrgico de mama unilateral e esvaziamento axilar, sem metástase. O linfedema apresentou-se em 39,03% (32) e parece não interferir muito na qualidade de vida das mulheres pós-câncer de mama, sendo a função social a mais prejudicada. Sintomas relacionados à quimioterapia e a mama incomodam as mulheres de ambos grupos, porém os sintomas relacionados aos braços foram estatisticamente maiores nas portadoras de linfedema. As estratégias mais utilizadas pelas entrevistadas para enfrentar o câncer foram a reavaliação, resolução de problemas, fuga, suporte social e autocontrole, somente o autocontrole foi estatisticamente maior nas mulheres com linfedema. As estratégias de resolução de problemas, autocontrole e baixo suporte social podem ter colaborado para o desencadeamento do linfedema. Conclui-se que o uso de estratégias ativas e positivas para enfrentar o câncer de mama parece resultar na boa adaptação psicossocial

QUALIDADE DE VIDA E ESTRATÉGIAS DE ENFRENTAMENTO DE MULHERES COM E SEM LINFEDEMA APÓS CÂNCER DE MAMA

O linfedema no membro superior é uma complicação inerente ao tratamento de câncer de mama. Caracterizado pelo aumento do volume do membro, leva às limitações físicas e funcionais, e impacto negativo no âmbito psicológico e social. O objetivo deste estudo foi investigar a qualidade de vida e seus domínios, as estratégias de enfrentamento frente ao câncer de mama, e a correlação entre essas variáveis. Este estudo foi realizado em um centro de saúde dedicado às mulheres, por quatro meses. Os instrumentos de avaliação foram: questionário de caracterização geral e específico do câncer de mama, perimetria dos membros superiores; questionários de qualidade de vida da Organização Européia de Pesquisa e Tratamento do Câncer, EORTC QLQ-30 e BR-23; e Inventário de Estratégias de Coping. Foram entrevistadas 82 mulheres, idade média de 57,4 anos (DV12,3), submetidas a tratamento cirúrgico de mama unilateral e esvaziamento axilar, sem metástase. O linfedema apresentou-se em 39,03% (32) e parece não interferir muito na qualidade de vida das mulheres pós-câncer de mama, sendo a função social a mais prejudicada. Sintomas relacionados à quimioterapia e a mama incomodam as mulheres de ambos grupos, porém os sintomas relacionados aos braços foram estatisticamente maiores nas portadoras de linfedema. As estratégias mais utilizadas pelas entrevistadas para enfrentar o câncer foram a reavaliação, resolução de problemas, fuga, suporte social e autocontrole, somente o autocontrole foi estatisticamente maior nas mulheres com linfedema. As estratégias de resolução de problemas, autocontrole e baixo suporte social podem ter colaborado para o desencadeamento do linfedema. Conclui-se que o uso de estratégias ativas e positivas para enfrentar o câncer de mama parece resultar na boa adaptação psicossocial

Pig but not human interferon-γ initiates human cell-mediated rejection of pig tissue in vivo

Split-thickness pig skin was transplanted on severe combined immunodeficient mice so that pig dermal microvessels spontaneously inosculated with mouse microvessels and functioned to perfuse the grafts. Pig endothelial cells in the healed grafts constitutively expressed class I and class II major histocompatibility complex molecules. Major histocompatibility complex molecule expression could be further increased by intradermal injection of pig interferon-γ (IFN-γ) but not human IFN-γ or tumor necrosis factor. Grafts injected with pig IFN-γ also developed a sparse infiltrate of mouse neutrophils and eosinophils without evidence of injury. Introduction of human peripheral blood mononuclear cells into the animals by intraperitoneal inoculation resulted in sparse perivascular mononuclear cell infiltrates in the grafts confined to the pig dermis. Injection of pig skin grafts on mice that received human peripheral blood mononuclear cells with pig IFN-γ (but not human IFN-γ or heat-inactivated pig IFN-γ) induced human CD4+ and CD8+ T cells and macrophages to more extensivley infiltrate the pig skin grafts and injure pig dermal microvessels. These findings suggest that human T cell-mediated rejection of xenotransplanted pig organs may be prevented if cellular sources of pig interferon (e.g., passenger lymphocytes) are eliminated from the graft.

Induction of inhibitory factor κBα mRNA in the central nervous system after peripheral lipopolysaccharide administration: An in situ hybridization histochemistry study in the rat

In this study we investigate the mRNA expression of inhibitory factor κBα (IκBα) in cells of the rat brain induced by an intraperitoneal (i.p.) injection of lipopolysaccharide (LPS). IκB controls the activity of nuclear factor κB, which regulates the transcription of many immune signal molecules. The detection of IκB induction, therefore, would reveal the extent and the cellular location of brain-derived immune molecules in response to peripheral immune challenges. Low levels of IκBα mRNA were found in the large blood vessels and in circumventricular organs (CVOs) of saline-injected control animals. After an i.p. LPS injection (2.5 mg/kg), dramatic induction of IκBα mRNA occurred in four spatio-temporal patterns. Induced signals were first detected at 0.5 hr in the lumen of large blood vessels and in blood vessels of the choroid plexus and CVOs. Second, at 1–2 hr, labeling dramatically increased in the CVOs and choroid plexus and spread to small vascular and glial cells throughout the entire brain; these responses peaked at 2 hr and declined thereafter. Third, cells of the meninges became activated at 2 hr and persisted until 12 hr after the LPS injection. Finally, only at 12 hr, induced signals were present in ventricular ependyma. Thus, IκBα mRNA is induced in brain after peripheral LPS injection, beginning in cells lining the blood side of the blood–brain barrier and progressing to cells inside brain. The spatiotemporal patterns suggest that cells of the blood–brain barrier synthesize immune signal molecules to activate cells inside the central nervous system in response to peripheral LPS. The cerebrospinal fluid appears to be a conduit for these signal molecules.

Severe reduction in leukocyte adhesion and monocyte extravasation in mice deficient in CC chemokine receptor 2

CC chemokine receptor 2 (CCR2) is a prominent receptor for the monocyte chemoattractant protein (MCP) group of CC chemokines. Mice generated by gene targeting to lack CCR2 exhibit normal leukocyte rolling but have a pronounced defect in MCP-1-induced leukocyte firm adhesion to microvascular endothelium and reduced leukocyte extravasation. Constitutive macrophage trafficking into the peritoneal cavity was not significantly different between CCR2-deficient and wild-type mice. However, after intraperitoneal thioglycollate injection, the number of peritoneal macrophages in CCR2-deficient mice did not rise above basal levels, whereas in wild-type mice the number of macrophages at 36 h was ≈3.5 times the basal level. The CCR2-deficient mice showed enhanced early accumulation and delayed clearance of neutrophils and eosinophils. However, by 5 days neutrophils and eosinophils in both CCR2-deficient and wild-type mice had returned to near basal levels, indicating that resolution of this inflammatory response can occur in the absence of macrophage influx and CCR2-mediated activation of the resident peritoneal macrophages. After intravenous injection with yeast β-glucan, wild-type mice formed numerous large, well-defined granulomas throughout the liver parenchyma, whereas CCR2-deficient mice had much fewer and smaller granulomas. These results demonstrate that CCR2 is a major regulator of induced macrophage trafficking in vivo.

Ethanolamine modulates the rate of rat hepatocyte proliferation in vitro and in vivo

A low molecular weight, heat-resistant hepatotrophic factor in an extract from the bovine intestinal mucosa was purified and identified as ethanolamine by structural analyses. The mode of action of ethanolamine in vitro and in vivo coincided with that of the crude extract of the tissue, indicating that ethanolamine is the active component. Ethanolamine synergistically elevated the stimulation of DNA synthesis in hepatocytes in primary culture when added together with a growth factor, such as epidermal growth factor, with the ED50 being 20 μM, although it showed little stimulatory effect by itself. Contrary to these in vitro results, the intraperitoneal administration of ethanolamine hydrochloride (24 mg of ethanolamine per kg of body weight) enhanced hepatocyte proliferation in regenerating rat livers after two-thirds hepatectomy without the administration of any growth factors. In the regenerating liver, hepatocyte proliferation may be initiated by an endogenous growth factor, but the supply of ethanolamine in circulation may not be sufficient for optimal hepatocyte proliferation; thus, the exogenous administration of ethanolamine may further enhance hepatocyte proliferation. Ethanolamine in circulation may be a humoral hepatotrophic factor.

Antitumor activity and pharmacokinetics of a mixed-backbone antisense oligonucleotide targeted to the RIα subunit of protein kinase A after oral administration

Overexpression of the RIα subunit of cAMP-dependent protein kinase (PKA) has been demonstrated in various human cancers. PKA has been suggested as a potential target for cancer therapy. The goal of the present study was to evaluate an anti-PKA antisense oligonucleotide (mixed-backbone oligonucleotide) as a therapeutic approach to human cancer treatment. The identified oligonucleotide inhibited the growth of cell lines of human colon cancer (LS174T, DLD-1), leukemia (HL-60), breast cancer (MCF-7, MDA-MB-468), and lung cancer (A549) in a time-, concentration-, and sequence-dependent manner. In a dose-dependent manner, the oligonucleotide displayed in vivo antitumor activity in severe combined immunodeficient and nude mice bearing xenografts of human cancers of the colon (LS174T), breast (MDA-MB-468), and lung (A549). The routes of drug administration were intraperitoneal and oral. Synergistic effects were found when the antisense oligonucleotide was used in combination with the cancer chemotherapeutic agent cisplatin. The pharmacokinetics of the oligonucleotide after oral administration of 35S-labeled oligonucleotide into tumor-bearing mice indicated an accumulation and retention of the oligonucleotide in tumor tissue. This study further provides a basis for clinical studies of the antisense oligonucleotide targeted to the RIα subunit of PKA (GEM 231) as a cancer therapeutic agent used alone or in combination with conventional chemotherapy.

Promoting detachment of neutrophils adherent to murine postcapillary venules to control inflammation: Effect of lipocortin 1

In this study we investigated, using intravital microscopy, how neutrophil extravasation across mouse mesenteric postcapillary venules is inhibited by the glucocorticoid-regulated protein lipocortin (LC; also termed annexin) 1. Intraperitoneal injection of 1 mg of zymosan into mice induced neutrophil rolling on the activated mesenteric endothelium followed by adhesion (maximal at 2 hr: 5–6 cells per 100-μm of vessel length) and emigration (maximal at 4 hr: 8–10 cells per high-powered field). Treatment of mice with human recombinant LC1 (2 mg/kg s.c.) or its mimetic peptide Ac2–26 (13 mg/kg s.c.) did not modify cell rolling but markedly reduced (≥50%) the degree of neutrophil adhesion and emigration (P < 0.05). Intravenous treatment with peptide Ac2–26 (13 mg/kg) or recombinant human LC1 (0.7–2 mg/kg) promoted detachment of neutrophils adherent to the endothelium 2 hr after zymosan administration, with adherent cells detaching within 4.12 ± 0.75 min and 2.36 ± 0.31 min, respectively (n = 20–25 cells). Recruitment of newly adherent cells to the endothelium was unaffected. The structurally related protein LC5 was inactive in this assay, whereas a chimeric molecule constructed from the N terminus of LC1 (49 aa) attached to the core region of LC5 produced cell detachment with kinetics similar to LC1. Removal of adherent neutrophils from activated postcapillary endothelium is a novel pharmacological action, and it is at this site where LC1 and its mimetics operate to down-regulate this aspect of the host inflammatory response.

Neurosteroids: Deficient cognitive performance in aged rats depends on low pregnenolone sulfate levels in the hippocampus

Pregnenolone sulfate (PREG S) is synthesized in the nervous system and is a major neurosteroid in the rat brain. Its concentrations were measured in the hippocampus and other brain areas of single adult and aged (22–24 month-old) male Sprague–Dawley rats. Significantly lower levels were found in aged rats, although the values were widely scattered and reached, in about half the animals, the same range as those of young ones. The spatial memory performances of aged rats were investigated in two different spatial memory tasks, the Morris water maze and Y-maze. Performances in both tests were significantly correlated and, accompanied by appropriate controls, likely evaluated genuine memory function. Importantly, individual hippocampal PREG S and distance to reach the platform in the water maze were linked by a significant correlation, i.e., those rats with lower memory deficit had the highest PREG S levels, whereas no relationship was found with the PREG S content in other brain areas (amygdala, prefrontal cortex, parietal cortex, striatum). Moreover, the memory deficit of cognitively impaired aged rats was transiently corrected after either intraperitoneal or bilateral intrahippocampal injection of PREG S. PREG S is both a γ-aminobutyric acid antagonist and a positive allosteric modulator at the N-methyl-d-aspartate receptor, and may reinforce neurotransmitter system(s) that decline with age. Indeed, intracerebroventricular injection of PREG S was shown to stimulate acetylcholine release in the adult rat hippocampus. In conclusion, it is proposed that the hippocampal content of PREG S plays a physiological role in preserving and/or enhancing cognitive abilities in old animals, possibly via an interaction with central cholinergic systems. Thus, neurosteroids should be further studied in the context of prevention and/or treatment of age-related memory disorders.

Agonist-selective endocytosis of mu opioid receptor by neurons in vivo.

Opiate alkaloids are potent analgesics that exert multiple pharmacological effects in the nervous system by activating G protein-coupled receptors. Receptor internalization upon stimulation may be important for desensitization and resensitization, which affect cellular responsiveness to ligands. Here, we investigated the agonist-induced internalization of the mu opioid receptor (MOR) in vivo by using the guinea pig ileum as a model system and immunohistochemistry with an affinity-purified antibody to the C terminus of rat MOR. Antibody specificity was confirmed by the positive staining of human embryonic kidney 293 cells transfected with epitope-tagged MOR cDNA, by the lack of staining of cells transfected with the delta or kappa receptor cDNA, and by the abolition of staining when the MOR antibody was preadsorbed with the MOR peptide fragment. Abundant MOR immunoreactivity (MOR-IR) was localized to the cell body, dendrites, and axonal processes of myenteric neurons. Immunostaining was primarily confined to the plasma membrane of cell bodies and processes. Within 15 min of an intraperitoneal injection of the opiate agonist etorphine, intense MOR-IR was present in vesicle-like structures, which were identified as endosomes by confocal microscopy. At 30 min, MOR-IR was throughout the cytoplasm and in perinuclear vesicles. MOR-IR was still internalized at 120 min. Agonist-induced endocytosis was completely inhibited by the opiate antagonist naloxone. Interestingly, morphine, a high-affinity MOR agonist, did not cause detectable internalization, but it partially inhibited the etorphine-induced MOR endocytosis. These results demonstrate the occurrence of agonist-selective MOR endocytosis in neurons naturally expressing this receptor in vivo and suggest the existence of different mechanisms regulating cellular responsiveness to ligands.