RESUMEN
BACKGROUND AND AIMS: The increased iron level and the labile iron pool (LIP) in circulating monocytes are connected to a higher frequency of cardiovascular events. METHODS: The study investigates the relationship between LIP in circulating monocytes and markers of iron metabolism and atherosclerosis (inflammation, oxidative stress, endothelial dysfunction and arterial elasticity) in long-term blood donors and non-donor volunteers. RESULTS: We found that donors had significantly higher LIP values than the control group (1.89⯱â¯0.47⯵M vs. 1.50⯱â¯0.41⯵M, p = 0.007). Despite the observed tendency for the donor group to have higher blood pressure, cholesterol, glucose and HOMAR-IR (homeostasis model assessment of insulin resistance), the groups did not differ in inflammatory markers, markers of endothelial dysfunction and markers of impaired arterial elasticity. The donor group had significant changes in iron metabolism (higher serum Fe, ceruloplasmin, and TfR/Ft ratio (transferrin receptor/ferritin ratio) and lower hepcidin, ferritin, and CD163), indicating depletion of body iron stores and activation of iron turnover. CONCLUSIONS: LIP seems to be a good marker of iron turnover activity in these individuals despite the lack of a decrease in the hemoglobin concentration. We did not find a significant correlation between LIP levels and atherosclerosis progression in the two groups. However, further studies are needed to assess long-term donorship as a protective factor against atherosclerosis.
Asunto(s)
Aterosclerosis/sangre , Donantes de Sangre , Enfermedades Cardiovasculares/sangre , Ferritinas/sangre , Hierro/metabolismo , Algoritmos , Ceruloplasmina/análisis , Endotelio Vascular/patología , Hepcidinas/sangre , Humanos , Inflamación , Resistencia a la Insulina , Hierro/sangre , Masculino , Persona de Mediana Edad , Estrés Oxidativo , Riesgo , Factores de Riesgo , Transferrina/análisisRESUMEN
BACKGROUND: Glycogen synthase kinase-3ß (GSK3ß), cAMP-response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) play critical roles in neuronal survival, synaptic plasticity and memory and participate in the pathophysiology of both depressive disorder and Alzheimer's disease (AD). METHODS: This study was designed to determine the association of GSK3ß activity, CREB activity and BDNF concentration in peripheral blood of patients with AD with or without depressive symptoms and in depressive patients without AD. GSK3ß activity in platelets, CREB activity in lymphocytes and BDNF concentration in plasma, platelet-rich plasma or platelets were measured in 85 AD patients (36 of whom displayed co-morbid depressive symptoms), 65 non-AD patients with depressive disorder and 96 healthy controls. AD patients were clinically assessed for stage of dementia, cognitive impairment and severity of depressive symptoms. Depressive patients were clinically assessed for severity of depression. RESULTS: We observed increased CREB activity and GSK3ß activity in AD with depressive symptoms or in AD at mild stage of dementia. Decreased BDNF concentration was found in platelet-rich plasma of AD patients at moderate to severe stages of dementia or in AD without depressive symptoms. An association was revealed of the severity of cognitive impairment with the increase of GSK3ß in the platelets of AD patients with mild dementia. In depressive patients, a lower concentration of phosphorylated GSK3ß was associated with a higher severity of depression. Association was confirmed between severity of depression, CREB activation, and BDNF concentration in drug-naïve depressive patients. CONCLUSION: Our data demonstrated that AD is accompanied by increased CREB activity in lymphocytes and a decreased concentration of BDNF in platelet-rich plasma. The decreased BDNF concentration appears to correlate with moderate to severe stages of dementia in AD. Observation of decreased phosphorylation of GSK3ß in platelets of both AD patients with depressive symptoms and depressive patients after treatment confirms the role of increased GSK3ß activity in the pathophysiology of both AD and depressive disorder. Associations were confirmed between AD and platelet GSK3ß activity, lymphocyte CREB activity and plasma BDNF. CREB activity and platelet BDNF concentration seems to be related to depressive disorder.
Asunto(s)
Enfermedad de Alzheimer/sangre , Enfermedad de Alzheimer/complicaciones , Factor Neurotrófico Derivado del Encéfalo/sangre , Proteína de Unión a CREB/sangre , Depresión/sangre , Depresión/complicaciones , Glucógeno Sintasa Quinasa 3/sangre , Anciano , Enfermedad de Alzheimer/psicología , Estudios de Casos y Controles , Depresión/psicología , Femenino , Glucógeno Sintasa Quinasa 3 beta , Humanos , Masculino , Persona de Mediana Edad , Pruebas Neuropsicológicas , Escalas de Valoración PsiquiátricaRESUMEN
BACKGROUND/AIMS: Podocytes are typically cultured on collagen I; however, collagen I is absent from healthy glomerular basement membranes. Erythropoietin (EPO) is thought to protect podocytes in vivo. Here, we studied how various types of extracellular matrix (ECM) proteins and EPO affect podocytes in culture. METHODS: Primary rat podocytes were replated on collagen I, collagen IV, whole ECM extract, laminin, or bare plastic. Cellular adhesion (8 hours after plating), proliferation (5 days, 10 % serum), and resistance to serum deprivation (3 days, 0.5 % serum) were assessed. BrdU incorporation and expression of podocyte-specific markers were employed as measures of cellular proliferation and differentiation, respectively. qPCR was used to verify expression of EPO receptor in cultured podocytes. RESULTS: Cellular adhesion was similar on all ECM proteins and unaffected by EPO. Proliferation was accelerated by laminin and the ECM extract, but the final cell density was similar on all ECM surfaces. Collagen IV supported the serum-deprived cells better than the other ECM proteins. EPO (2-20 ng/ml) improved viability of serum-deprived podocytes on collagen I, collagen IV, and ECM, but not on laminin or bare plastic. The cells expressed mRNA for EPO receptor. CONCLUSION: The physiological ECM proteins are more supportive of primary podocytic cultures compared with collagen I. The protective effects of EPO during serum deprivation are modulated by the cultivation surface.
Asunto(s)
Eritropoyetina/farmacología , Proteínas de la Matriz Extracelular/fisiología , Glomérulos Renales/efectos de los fármacos , Podocitos/efectos de los fármacos , Animales , Células Cultivadas , Colorantes , Matriz Extracelular/efectos de los fármacos , Matriz Extracelular/metabolismo , Cultivo Primario de Células , Ratas , Receptores de Eritropoyetina/biosíntesis , Receptores de Eritropoyetina/efectos de los fármacos , Proteínas Recombinantes/farmacología , Sales de Tetrazolio , TiazolesRESUMEN
The mitochondrial permeability transition (MPT) plays an important role in cell death. The MPT is triggered by calcium and promoted by oxidative stress, which is often catalyzed by iron. We investigated the induction of the MPT by physiological concentrations of iron. Isolated rat liver mitochondria were initially stabilized with EDTA and bovine serum albumin and energized by succinate or malate/pyruvate. The MPT was induced by 20µM calcium or ferrous chloride. We measured mitochondrial swelling, the inner membrane potential, NAD(P)H oxidation, iron and calcium in the recording medium. Iron effectively triggered the MPT; this effect differed from non-specific oxidative damage and required some residual EDTA in the recording medium. Evidence in the literature suggested two mechanisms of action for the iron: NAD(P)H oxidation due to loading of the mitochondrial antioxidant defense systems and uptake of iron to the mitochondrial matrix via a calcium uniporter. Both of these events occurred in our experiments but were only marginally involved in the MPT induced by iron. The primary mechanism observed in our experiments was the displacement of adventitious/endogenous calcium from the residual EDTA by iron. Although artificially created, this interplay between iron and calcium can well reflect conditions in vivo and could be considered as an important mechanism of iron toxicity in the cells.
Asunto(s)
Calcio/metabolismo , Hierro/farmacología , Proteínas de Transporte de Membrana Mitocondrial/fisiología , NAD/metabolismo , Animales , Carbonil Cianuro p-Trifluorometoxifenil Hidrazona/farmacología , Masculino , Poro de Transición de la Permeabilidad Mitocondrial , Oxidación-Reducción , Ratas , Ratas WistarRESUMEN
Irradiation of the cornea with UVB rays leads to its oxidative damage, swelling and increased light absorption. We investigated changes in the corneal optics (evaluated by changes of corneal hydration and light absorption) and microscopical disturbances of corneas irradiated with UVB rays as influenced by eye drops containing actinoquinol with hyaluronic acid. Rabbit corneas were irradiated with a daily dose of 0.5 or 1.01 J cm(-2) of UVB rays (312 nm) for 4 days. During irradiation, the eye drops were applied on the right eye and buffered saline (or hyaluronic acid) on the left eye. On day 5 the rabbits were sacrificed and the corneas examined spectrophotometrically for light absorption. The corneal thickness (hydration) was measured using a pachymeter. Corneas of some other rabbits were examined immunohistochemically. After buffered saline treatment UVB rays evoked changes in the corneal optics and induced oxidative damage of the corneas. After actinoquinol-hyaluronic acid application, these changes were diminished. Hyaluronic acid alone was less effective. In conclusion, actinoquinol-hyaluronic acid eye drops decreased changes in corneal optics and suppressed oxidative damage in the UVB-irradiated cornea. However, the effective corneal protection by these eye drops was limited to the lower UVB dose.
Asunto(s)
Córnea/efectos de los fármacos , Córnea/efectos de la radiación , Ácido Hialurónico/administración & dosificación , Quinolinas/administración & dosificación , Rayos Ultravioleta/efectos adversos , Animales , Córnea/metabolismo , Opacidad de la Córnea/prevención & control , Soluciones Oftálmicas , Estrés Oxidativo , Conejos , Protectores contra Radiación/administración & dosificaciónRESUMEN
The aim of the present paper was to examine the irradiation effect of two doses of UVA rays (365 nm) on the rabbit cornea and lens. Corneas of anesthetized adult albino rabbits were irradiated with UVA rays for 5 days (daily dose 1.01 J cm(-2) in one group of rabbits and daily dose 2.02 J cm(-2) in the second group of animals). The third day after the last irradiation, the rabbits were killed, and their eyes were employed for spectrophotometrical, biochemical and immunohistochemical investigations. Normal eyes served as controls. Absorption spectra of the whole corneal centers were recorded over the UV-VIS (visible) spectral range. Levels of antioxidant and prooxidant enzymes, nitric oxide synthases and nitric oxide (indirectly measured as nitrate concentration) were investigated in the cornea. Malondialdehyde, a byproduct of lipid peroxidation, was examined in the cornea and lens. The results show that the staining for endothelial nitric oxide synthase was more pronounced in corneas irradiated with the higher UVA dose. Otherwise, UVA rays at either dose did not significantly change corneal light absorption properties and did not cause statistically significant metabolic changes in the cornea or lens. In conclusion, UVA rays at the employed doses did not evoke harmful effects in the cornea or lens.
Asunto(s)
Córnea/efectos de la radiación , Cristalino/efectos de la radiación , Rayos Ultravioleta , Animales , Relación Dosis-Respuesta en la Radiación , ConejosRESUMEN
Under normal conditions, the cornea absorbs the majority of UVB (ultraviolet B, 280-320 nm) rays, which is very important for the protection of the inner eye against their damaging effect. Our previous studies have shown that repeated irradiation of the rabbit cornea with UVB rays for 5 days (daily dose of 1.01 J cm(- 2)) caused photokeratitis accompanied by swelling (hydration) of the corneal stroma, thinning of the corneal epithelium and decrease in antioxidants. The purpose of this study was to examine the light absorption properties of such damaged rabbit cornea. Results of both spectrophotometry of the whole corneal buttons and corneal tissue dissolved in sodium hydroxide show that because of above mentioned disturbances, UVB-irradiated cornea absorbs more light throughout the whole measurable UV-VIS spectral range than the normal cornea. Increased corneal thickness (result of hydration), changes of corneal transparency (the cornea becomes grayish) and some increase in protein content all contribute to the increased light absorption of UVB irradiated corneas. We suggest that the UVB-irradiated cornea, although damaged and nearly without antioxidants, might actually through its higher UV absorbance protect the inner eye against further damage from UVB rays.
Asunto(s)
Córnea/efectos de la radiación , Rayos Ultravioleta , Animales , Antioxidantes/análisis , Córnea/patología , Epitelio Corneal/efectos de la radiación , Queratitis/etiología , Conejos , Células del Estroma/efectos de la radiaciónRESUMEN
Cyclic AMP response element binding protein (CREB) is a constitutive transcription factor that activates transcription following stimulus-dependent phosphorylation at Ser133, implicated in synaptic plasticity and neuronal survival pathways. The prevailing view that CREB is exclusively nuclear has been questioned by several studies, and, for example, mitochondrial localization has been reported. Using subcellular fractionation of rat brain cortex coupled with western immunoblotting with Ser133-phospho-CREB (pCREB) antibodies, we found a robust pCREB immunoreactivity (IR) in mitochondria-enriched fractions. The pCREB antibodies also stained the mitochondria, in addition to nuclei, of glial cells in primary cortical cultures. However, two CREB antibodies against different epitopes and gel shift assay detected the CREB protein mainly in the nuclear fraction. The two-dimensional electrophoretic mobility of mitochondrial pCREB IR differed markedly from the nuclear CREB/pCREB IR, indicating that the pCREB antibody cross-reacts with another mitochondrial protein. Immunoprecipitation of the mitochondrial pCREB IR produced three bands on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry as E2, E1 alpha-subunit, and E1 beta-subunit of pyruvate dehydrogenase complex. The cross-reacting epitope was identified as phospho-Ser300 of the alpha-subunit. In conclusion, this study confirms the presence of pCREB-like IR in brain mitochondria that, after careful scrutiny, turned out to be pyruvate dehydrogenase rather than authentic CREB.
Asunto(s)
Encéfalo/metabolismo , Proteína de Unión a CREB/metabolismo , Mitocondrias/metabolismo , Piruvato Descarboxilasa/metabolismo , Serina/metabolismo , Adenosina Trifosfato/farmacología , Animales , Anticuerpos/metabolismo , Western Blotting/métodos , Encéfalo/citología , Proteína de Unión a CREB/inmunología , Células Cultivadas , Relación Dosis-Respuesta a Droga , Interacciones Farmacológicas , Complejo IV de Transporte de Electrones/metabolismo , Electroforesis en Gel Bidimensional/métodos , Ensayo de Cambio de Movilidad Electroforética , Técnica del Anticuerpo Fluorescente/métodos , Proteína Ácida Fibrilar de la Glía/metabolismo , Inmunoprecipitación/métodos , Magnesio/farmacología , Masculino , Microscopía Confocal/métodos , Fosforilación , Ratas , Ratas Wistar , Receptores de N-Metil-D-Aspartato/metabolismo , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Fracciones Subcelulares/metabolismoRESUMEN
We have directed a polyclonal antibody against an oligo-peptide (123-136) of the transcription factor cyclic AMP responsive element-binding protein (CREB) including the serine residue at 133. Rabbit sera were purified by ammonium sulfate precipitation, followed by affinity chromatography to homogeneity on one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis. The purified antibody not only induced marked supershift of CREB binding, without affecting binding of activator protein-1 on gel retardation electrophoresis, but also differentiated between CREB and CREB phosphorylated at serine133 in brain nuclear fractions on Western blotting. Immunoreactive CREB was detected in both cytosolic and nuclear fractions of discrete murine brain structures but was more highly condensed in cerebellum than in neocortex and hippocampus. Incubation of brain nuclear fractions led to a marked export of immunoreactive CREB in a temperature-dependent manner, whereas the temperature-dependent export activity was significantly lower in cerebellum than in other brain structures. Suppression of general new protein synthesis by cycloheximide (500 mg/kg, i.p.) in vivo resulted in a significant decrease in the nuclear CREB level, with a concomitant increase in the cytosolic level in hippocampus, but not in cerebellum. These results suggest that the nuclear export activity might vary from region to region in murine brains through a hitherto unidentified mechanism other than the nuclear localization signal, to result in different nuclear condensation ratios for subsequent elicitation of differential transcriptional activities by the constitutive transcription factor CREB in the nucleus.
Asunto(s)
Transporte Activo de Núcleo Celular/fisiología , Encéfalo/metabolismo , Núcleo Celular/metabolismo , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/metabolismo , Animales , Anticuerpos/aislamiento & purificación , Especificidad de Anticuerpos , Encéfalo/citología , Cerebelo/citología , Cerebelo/metabolismo , Proteína de Unión a Elemento de Respuesta al AMP Cíclico/inmunología , Hipocampo/citología , Hipocampo/metabolismo , Masculino , Ratones , Neocórtex/citología , Neocórtex/metabolismo , Fragmentos de Péptidos/inmunología , Proteínas Proto-Oncogénicas c-jun/metabolismo , ConejosRESUMEN
The activities of superoxide dismutase, glutathione peroxidase (GPX) and catalase--the enzymatic scavengers of reactive oxygen species and the activities of xanthine oxidoreductase and xanthine oxidase, an enzyme known to generate reactive oxygen species, were studied in the corneas of normal rabbit eyes of various ages (1 month--young eyes; 4-9.5 months--young adult eyes; 2.0-2.75 years--middle aged eyes; 3.0-5.0 years--aged eyes). The activities of GPX, superoxide dismutase, xanthine oxidoreductase and xanthine oxidase were investigated biochemically in the scraped corneal epithelium. Catalase activity was detected histochemically in the corneal epithelium and endothelium. The results show that young corneas revealed lower activities of all the antioxidant enzymes investigated than did young adult corneas, in which enzymatic activities reached their maximum. In middle-aged corneas, GPX and catalase activities remained approximately at the same levels as seen in young adult corneas, whereas superoxide dismutase activity was decreased. In aged corneas, the activities of all antioxidant enzymes were dramatically decreased or even lost (catalase activity in the corneal endothelium). In contrast, xanthine oxidoreductase activity only slightly decreased with age and the xanthine oxidase proportion of total xanthine oxidoreductase remained unchanged. GPX, superoxide dismutase and catalase are important antioxidant enzymes protecting the cornea against the oxidative damage. Because the activities of these enzymes are lower in young animals and greatly reduced in aged animals, it is suggested that young and particularly aged corneas might be more susceptible to oxidative stress than are young adult corneas. This presumption is supported by the fact that the activities of prooxidant enzymes (xanthine oxidoreductase/xanthine oxidase) are only slightly decreased in aged corneas as compared to young adult corneas so that some imbalance between antioxidant and prooxidant enzymes exists already in the normal aged corneas.