Chronic Kidney Disease-Associated Pruritus and Quality of Life: Learning from Our Patients.

Chronic kidney disease-associated pruritus is itching directly related to kidney disease that cannot be explained by any other condition. Despite technological advances in the different aspects of dialysis sessions and the best treatment for chronic kidney disease patients, it is still a common problem in our patients. The many complex physiological mechanisms involved, the different hypotheses made over the years on the aetiology of the condition, and the great clinical variability may partially explain the limited knowledge about this problem and the difficulties in treating it. The presence of all these factors leads to the persistence of unpleasant symptoms, which must affect the disease burden and quality of life of kidney patients. Through the presentation of an illustrative clinical case, the aim of this review article is to highlight the need for adequate diagnosis and an improved approach to all aspects of chronic kidney disease-associated pruritus, in view of the heavy burden of the disease and the huge impact on the patient's quality of life.

New Strategies for Stroke Therapy: Nanoencapsulated Neuroglobin.

Stroke is a global health and socio-economic problem. However, no efficient preventive and/or palliative treatments have yet been found. Neuroglobin (Ngb) is an endogen neuroprotective protein, but it only exerts its beneficial action against stroke after increasing its basal levels. Therefore, its systemic administration appears to be an efficient therapy applicable to stroke and other neurodegenerative pathologies. Unfortunately, Ngb cannot cross the blood-brain barrier (BBB), making its direct pharmacological use unfeasible. Thus, the association of Ngb with a drug delivery system (DDS), such as nanoparticles (NPs), appears to be a good strategy for overcoming this handicap. NPs are a type of DDS which efficiently transport Ngb and increase its bioavailability in the infarcted area. Hence, we previously built hyaluronate NPS linked to Ngb (Ngb-NPs) as a therapeutic tool against stroke. This nanoformulation induced an improvement of the cerebral infarct prognosis. However, this innovative therapy is still in development, and a more in-depth study focusing on its long-lasting neuroprotectant and neuroregenerative capabilities is needed. In short, this review aims to update the state-of-the-art of stroke therapies based on Ngb, paying special attention to the use of nanotechnological drug-delivering tools.

Biological Implications of a Stroke Therapy Based in Neuroglobin Hyaluronate Nanoparticles. Neuroprotective Role and Molecular Bases.

Exogenous neuroprotective protein neuroglobin (Ngb) cannot cross the blood-brain barrier. To overcome this difficulty, we synthesized hyaluronate nanoparticles (NPs), able to deliver Ngb into the brain in an animal model of stroke (MCAO). These NPs effectively reached neurons, and were microscopically identified after 24 h of reperfusion. Compared to MCAO non-treated animals, those treated with Ngb-NPs showed survival rates up to 50% higher, and better neurological scores. Tissue damage improved with the treatment, but no changes in the infarct volume or in the oxidative/nitrosative values were detected. A proteomics approach (p-value < 0.02; fold change = 0.05) in the infarcted areas showed a total of 219 proteins that significantly changed their expression after stroke and treatment with Ngb-NPs. Of special interest, are proteins such as FBXO7 and NTRK2, which were downexpressed in stroke, but overexpressed after treatment with Ngb-NPs; and ATX2L, which was overexpressed only under the effect of Ngb. Interestingly, the proteins affected by the treatment with Ngb were involved in mitochondrial function and cell death, endocytosis, protein metabolism, cytoskeletal remodeling, or synaptic function, and in regenerative processes, such as dendritogenesis, neuritogenesis, or sinaptogenesis. Consequently, our pharmaceutical preparation may open new therapeutic scopes for stroke and possibly for other neurodegenerative pathologies.

Crosstalk between hydroxytyrosol, a major olive oil phenol, and HIF-1 in MCF-7 breast cancer cells.

Olive oil intake has been linked with a lower incidence of breast cancer. Hypoxic microenvironment in solid tumors, such as breast cancer, is known to play a crucial role in cancer progression and in the failure of anticancer treatments. HIF-1 is the foremost effector in hypoxic response, and given that hydroxytyrosol (HT) is one of the main bioactive compounds in olive oil, in this study we deepen into its modulatory role on HIF-1. Our results in MCF-7 breast cancer cells demonstrate that HT decreases HIF-1α protein, probably by downregulating oxidative stress and by inhibiting the PI3K/Akt/mTOR pathway. Strikingly, the expression of HIF-1 target genes does not show a parallel decrease. Particularly, adrenomedullin and vascular endothelial growth factor are up-regulated by high concentrations of HT even in HIF-1α silenced cells, pointing to HIF-1-independent mechanisms of regulation. In fact, we show, by in silico modelling and transcriptional analysis, that high doses of HT may act as an agonist of the aryl hydrocarbon receptor favoring the induction of these angiogenic genes. In conclusion, we suggest that the effect of HT in a hypoxic environment is largely affected by its concentration and involves both HIF-1 dependent and independent mechanisms.

Hyaluronate Nanoparticles as a Delivery System to Carry Neuroglobin to the Brain after Stroke.

Therapies against stroke can restore the blood supply but cannot prevent the ischemic damage nor stimulate the recovery of the infarcted zone. The neuroglobin protein plays an important role in the neuro-regeneration process after stroke; however, the method for its effective systemic application has not been identified yet, as neuroglobin is unable to pass through the blood-brain barrier. Previously, we developed different types of sodium hyaluronate nanoparticles, which successfully cross the blood-brain barrier after stroke. In this work, these nanoparticles have been used to carry neuroglobin through the bloodstream to the nerve cells in rats submitted to stroke. We have biosynthesized rat-recombinant neuroglobin and determined the formulation of sodium hyaluronate nanoparticles loaded with neuroglobin, as well as its size and ζ-potential, encapsulation efficiently, in vitro release, and its kinetic of liberation. The results show that the formulation achieved is highly compatible with pharmaceutical use and may act as a delivery system to transport neuroglobin within the blood. We have found that this formulation injected intravenously immediately after stroke reached the damaged cerebral parenchyma at early stages (2 h). Neuroglobin colocalizes with its nanocarriers inside the nerve cells and remains after 24 h of reperfusion. In conclusion, the systemic administration of neuroglobin linked to nanoparticles is a potential neuroprotective drug-delivery strategy after stroke episodes.

Lateral habenula lesions disrupt appetitive extinction, but do not affect voluntary alcohol consumption.

This study analyzed the effects of LHb lesions on appetitive extinction and alcohol consumption. Eighteen male Wistar rats received neurochemical lesions of the LHb (quinolinic acid) and 12 received a vehicle infusion (PBS). In a runway instrumental task, rats received acquisition (12 pellets/trial, 6 trials/session, 10 sessions) and extinction training (5 sessions). In a consummatory task, rats had daily access to 32% sucrose (5 min, 10 sessions) followed by access to water (5 sessions). Then, animals received 2 h preference tests with escalating alcohol concentrations (2%-24%), followed by two 24 h preference tests with 24% alcohol. Relative to Shams, LHb lesions delayed extinction, as indicated by lower response latencies (instrumental task) and higher fluid consumption (consummatory task). LHb lesions did not affect alcohol consumption regardless of alcohol concentration or test duration. The LHb modulates appetitive extinction and needs to be considered as part of the brain circuit underlying reward loss.

Are Patients With Fibromyalgia in a Prothrombotic State?

OBJECTIVES: The aim of this study was to investigate thrombosis-related parameters (blood coagulation parameters, platelet indices, red blood cell [RBC] count, and inflammatory markers) in patients with fibromyalgia (FM). METHOD: We carried out a case-control study with 35 women with FM and 12 age-matched healthy volunteers to analyze fibrinogen levels, prothrombin time, cephaline time, platelet count, platelet distribution width (PDW), mean platelet volume (MPV), RBC count, neutrophil-to-lymphocyte ratio, and platelet-to-lymphocyte ratio (PLR). RESULTS: The results showed significantly increased fibrinogen levels ( p < .05), platelet count ( p < .05), PDW ( p = .059), RBC count ( p < .05), and PLR ( p < .05) in women with FM versus the healthy volunteers. Prothrombin time ( p < .05) and MPV ( p < .05) were significantly lower in patients with FM than in the controls. CONCLUSIONS: Elevated platelet and RBC counts, PDW values, and fibrinogen levels as well as decreased prothrombin time are all indicative of a prothrombotic state in FM patients, which may be enhanced by an increased inflammatory tone. This prothrombotic state may increase the risk of thrombosis-related cardiovascular disease in patients with FM.

Comparative proteomic study of early hypoxic response in the cerebral cortex of rats submitted to two different hypoxic models.

PURPOSE: The present study analyses and compares the cortical brain proteomic profiles of two different models of cerebral hypoxic insult in rats (HH: hypobaric hypoxia and HHI: ischemia followed by hypobaric hypoxia) in an attempt to describe the alterations of the early molecular hypoxic adaptive response underlying each one. EXPERIMENTAL DESIGN: A quantitative proteomic profile of left-brain cortices of rats under HH, HHI, and control conditions was determined using isobaric labeling (Tandem Mass Tag™) on the protein extracts from pools of five individuals. Data are available via ProteomeXchange with identifier PXD004091. RESULTS: Altogether, 339 proteins were confidently quantified, 99 of them showing significant variations in the hypoxic conditions with respect to the control. The HHI model presents a global effect of protein downregulation while HH produces an overall increase of the protein levels. While HH mainly affecting oxidative and energetic metabolism, HHI also interferes with synaptic transmission, neurotransmitter secretion, substantia nigra development, and triggers apoptosis through mitochondrial pathway. CONCLUSIONS AND CLINICAL RELEVANCE: The findings obtained show an overview of protein alterations under two hypoxic models of different aetiology and provide a basis for more detailed studies in order to unravel new specific mechanisms and therapies for hypoxic pathologies.

Melatonin influences NO/NOS pathway and reduces oxidative and nitrosative stress in a model of hypoxic-ischemic brain damage.

In this work, using a rat model combining ischemia and hypobaric hypoxia (IH), we evaluate the relationships between the antioxidant melatonin and the cerebral nitric oxide/nitric oxide synthase (NO/NOS) system seeking to ascertain whether melatonin exerts its antioxidant protective action by balancing this key pathway, which is highly involved in the cerebral oxidative and nitrosative damage underlying these pathologies. The application of the IH model increases the expression of the three nitric oxide synthase (NOS) isoforms, as well as nitrogen oxide (NOx) levels and nitrotyrosine (n-Tyr) impacts on the cerebral cortex. However, melatonin administration before IH makes nNOS expression response earlier and stronger, but diminishes iNOS and n-Tyr expression, while both eNOS and NOx remain unchanged. These results were corroborated by nicotine adenine dinucleotide phosphate diaphorase (NADPH-d) staining, as indicative of in situ NOS activity. In addition, the rats previously treated with melatonin exhibited a reduction in the oxidative impact evaluated by thiobarbituric acid reactive substances (TBARS). Finally, IH also intensified glial fibrillary acidic protein (GFAP) expression, reduced hypoxia-inducible factor-1alpha (HIF-1α), but did not change nuclear factor kappa B (NF-κB); meanwhile, melatonin did not significantly affect any of these patterns after the application of the IH model. The antioxidant melatonin acts on the NO/NOS system after IH injury balancing the release of NO, reducing peroxynitrite formation and protecting from nitrosative/oxidative damage. In addition, this paper raises questions concerning the classical role of some controversial molecules such as NO, which are of great consequence in the final fate of hypoxic neurons. We conclude that melatonin protects the brain from hypoxic/ischemic-derived damage in the first steps of the ischemic cascade, influencing the NO/NOS pathway and reducing oxidative and nitrosative stress.

Effects of a human milk oligosaccharide, 2'-fucosyllactose, on hippocampal long-term potentiation and learning capabilities in rodents.

Human milk oligosaccharides (HMOs) are unique with regard to their diversity, quantity and complexity, particularly in comparison to bovine milk oligosaccharides. HMOs are associated with functional development during early life, mainly related to immunity and intestinal health. Whether HMOs elicit a positive effect on cognitive capabilities of lactating infants remains an open question. This study evaluated the role of the most abundant HMO, 2'-fucosyllactose (2'-FL), in synaptic plasticity and learning capabilities in rodents. Mice and rats were prepared for the chronic recording of field excitatory postsynaptic potentials evoked at the hippocampal CA3-CA1 synapse. Following chronic oral administration of 2'-FL, both species showed improvements in input/output curves and in long-term potentiation (LTP) evoked experimentally in alert behaving animals. This effect on LTP was related to better performance of animals in various types of learning behavioral tests. Mice were tested for spatial learning, working memory and operant conditioning using the IntelliCage system, while rats were submitted to a fixed-ratio schedule in the Skinner box. In both cases, 2'-FL-treated animals performed significantly better than controls. In addition, chronic administration of 2'-FL increased the expression of different molecules involved in the storage of newly acquired memories, such as the postsynaptic density protein 95, phosphorylated calcium/calmodulin-dependent kinase II and brain-derived neurotrophic factor in cortical and subcortical structures. Taken together, the data show that dietary 2'-FL affects cognitive domains and improves learning and memory in rodents.

Proteomic characterization of nitrated cell targets after hypobaric hypoxia and reoxygenation in rat brain.

This study analyzes the nitrated protein profile of the rat-brain cortex in a model of hypoxia/reoxygenation, identifying the nitrated proteins and assessing spot changes. The proteins identified were grouped into categories, according to their function: 1) metabolism: pyruvate kinase (PK), α-enolase, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), phosphoglycerate mutase 1 (PGAM1), and glutamine synthetase (GS); 2) cytoskeletal proteins: α-tubulin, ß-tubulin, γ-actin, and glial fibrillary acidic protein (GFAP); 3) chaperones: heat-shock protein 71kDa (HSP71); and 4) carrier proteins: voltage-dependent anion-selective channel protein 1 (VDAC-1) and Atp6v1a. PK, α-enolase, and GS nitration rates were upregulated, increasing progressively during reoxygenation and peaking at 24h. GAPDH and PGAM1 nitration levels fell after hypoxia/reoxygenation. α-Tubulin, ß-tubulin, γ-actin, and GFAP nitration rates augmented at 24h, but diminished at 5d. HSP71 suffered from nitration immediately after hypoxia, but not during reoxygenation. VDAC-1 tyrosine nitration was identified only in the control group, whereas detectable Atp6v1a nitration levels were observed only immediately after hypoxia. The data have been deposited to the ProteomeXchange with identifier PXD001049. Our findings suggest a hypothetically crucial linkage between nitration-related protein modifications and metabolic and cell-structure alterations. These changes are probably needed for the remodeling and plasticity processes activated by the hypoxic brain response. BIOLOGICAL SIGNIFICANCE: For the first time the spectrum of nitrated proteins in the hypoxic brain as well as its changes during reoxygenation are described. Our findings suggest a hypothetically crucial linkage between nitration-related protein modifications and metabolic and cell-structure alterations. These changes are probably needed for the remodeling and plasticity processes activated by the hypoxic brain response. The biological relevance of these findings is linked to the important role developed by the signaling molecule NO in the hypoxic brain, and could be interpreted in two different but complementary ways: first, as a mechanism of damage due to nitration impacts over some key proteins affecting its structure and function; and second, as a regulation mechanism involved in the hypoxic response. Hence, based on the modified proteins identified and their functions, it would be possible to design new tools and therapies to prevent brain damage in low-oxygen-pressure atmospheres.

Hypobaric hypoxia and reoxygenation induce proteomic profile changes in the rat brain cortex.

Brain, due to its high metabolism, is severely affected by hypoxia/reoxygenation. In this study, cerebral cortexes from rats subjected to hypobaric hypoxia followed by several reoxygenation periods (0 h, 24 h, and 5 days) were compared with normobaric normoxic controls to identify protein-expression differences using proteomic approaches. Only 2-fold differences in spot abundance between controls and experimental groups from each reoxygenation period were considered. The proteins identified were grouped into categories, according to their similarity in function or to their involvement in the same metabolic pathway. We distinguished five groups: (1) glycolysis, including γ-enolase (NSE), and glyceraldehyde 3-phosphate dehydrogenase (GAPDH); (2) tricarboxylic acid cycle, such as aconitate hydratase (ACO2); (3) oxidative phosphorylation, like F1-ATPase chains α and ß; (4) cytoskeletal, including Spna2, α-tubulin, ß-tubulin, ß-actin, and microtubule-associated protein RP/EB family member 3 (EB3); and (5) chaperones, like heat-shock protein 72 kDa (HSP72). NSE was upregulated while GAPDH was downregulated, both peaking at 5 days post-hypoxia. ACO2 and F1-ATPase decreased in all the reoxygenation periods. Spna2 and EB3 were expressed neither in control nor at 0 h, but 5 days post-hypoxia new expression took place. The α- and ß-tubulin levels significantly fell at 0 h, but after 24 h strongly increased. Also, ß-actin and HSP72 were downregulated, and the last one reached the lowest level at 24 h of reoxygenation. We conclude that the molecular mechanisms underlying hypoxia/reoxygenation in the rat cortex might consist of a close relationship between energy metabolism, cytoskeleton, and chaperones. These findings may shed light on therapeutic targets against hypoxia-related damage.

Study of the nitric oxide system in the rat cerebellum during aging.

BACKGROUND: The cerebellum is the neural structure with the highest levels of nitric oxide, a neurotransmitter that has been proposed to play a key role in the brain aging, although knowledge concerning its contribution to cerebellar senescence is still unclear, due mainly to absence of integrative studies that jointly evaluate the main factors involved in its cell production and function. Consequently, in the present study, we investigate the expression, location, and activity of nitric oxide synthase isoenzymes; the protein nitration; and the production of nitric oxide in the cerebellum of adult and old rats. RESULTS: Our results show no variation in the expression of nitric oxide synthase isoforms with aging, although, we have detected some changes in the cellular distribution pattern of the inducible isoform particularly in the cerebellar nuclei. There is also an increase in nitric oxide synthase activity, as well as greater protein-nitration levels, and maintenance of nitrogen oxides (NOx) levels in the senescent cerebellum. CONCLUSIONS: The nitric oxide/nitric oxide synthases system suffers from a number of changes, mainly in the inducible nitric oxide synthase distribution and in overall nitric oxide synthases activity in the senescent cerebellum, which result in an increase of the protein nitration. These changes might be related to the oxidative damage detected with aging in the cerebellum.

Polyphenol oxidase and its relationship with oleuropein concentration in fruits and leaves of olive (Olea europaea) cv. 'Picual' trees during fruit ripening.

Oleuropein, the main phenolic compound of olive fruit, has important antioxidant properties that are responsible for some of the nutritional properties of fruits and the defence mechanism of leaves. Polyphenol oxidase (PPO) activity changes during fruit ripening in many plants. We studied the kinetics and molecular properties of PPO in fruits and leaves of olive (Olea europaea L.) cv. 'Picual' trees and the relationship between PPO and oleuropein concentration during fruit ripening. Polyphenol oxidase showed hyperbolic kinetics in fruits and leaves. Significant increases in PPO specific activity, V(max), K(m )and catalytic efficiency occurred during fruit ripening. Based on SDS-PAGE under partially denaturing conditions and in-gel staining with DL-3,4-dihydroxyphenylalanine, PPO activity was found in one major protein of 55 and 50 kDA in fruits and leaves, respectively. During the last stages of fruit maturation, a second 36 kDa protein was observed in fruits but not in leaves, indicating that this protein could serve as a marker of the final phase of fruit maturation. Under fully denaturing conditions, only one 27.7 kDa immunoreactive band was detected in fruits. Both the amount of PPO activity and the amount of PPO protein increased significantly during fruit maturation. Immunohistochemical studies indicated that PPO is located in the epidermis, parenchyma and companion vascular cells of leaves as well as in the epidermis of fruit. During fruit maturation, oleuropein concentration measured by HPLC significantly decreased in fruits and increased in leaves.

Age modulates the nitric oxide system response in the ischemic cerebellum.

To determine whether age influences the nitric oxide system response to ischemia in the cerebellum, we have analyzed the levels of nitrogen oxides (NOx) and the expression of the different nitric oxide synthase isoforms (NOS) in mature adult (4-5 months old) and aged rats (24-27 months old) subjected to a transient global ischemia/reperfusion (I/R) model. We also analyzed the nitrated proteins and the glial fibrillary acidic protein (GFAP) expression. NOx concentration in adult rats, which more than doubled the values found in the aged rats, decreased after the ischemia and reperfusion. However, in the aged animals, these NOx levels did not significantly change after I/R. Constitutive isoforms were first down-regulated in the ischemic period, in both adult and aged animals. However, after 6 h of reperfusion, these isoforms were up-regulated, but only in aged rats. After I/R, iNOS was up-regulated in adults but down-regulated in the aged rats. Hence, after an episode of transient global ischemia and reperfusion, the aged cerebellum maintains a balanced NO production, silencing the iNOS isoform and inducing a weak expression of nNOS and eNOS; this allows NO physiological functions while avoiding possible undesirable effects such as the nitrative damage or astrocyte activation.

Steatosis recovery after treatment with a balanced sunflower or olive oil-based diet: involvement of perisinusoidal stellate cells.

AIM: To analyze the relationship between perisinusoidal stellate cell (PSC) activation and the dietary fat quantity and composition in the treatment of hepatic steatosis. METHODS: Using an experimental rat model of steatosis based on the intake of a hyperlipidic diet (14% fat as olive oil or sunflower oil, HL-O and HL-S, respectively), we analyzed the liver's capability of recovery after the treatment with a normal-lipidic diet (5% fat as olive oil or sunflower oil, NL-O and NL-S, respectively) by immunocytochemical and Western blot analysis of glial fibrillary acidic protein (GFAP) expression in PSCs, collagen quantification and serum aminotransferase determination. RESULTS: The fatty infiltration in the steatotic livers decreased after the treatment with both NL diets, indicating liver recovery. This decrease was accompanied with a lower collagen deposition and aminotransferase level as well as changes in the PSC population that increased the GFAP expression. The above-mentioned effects were more pronounced in animals fed on NL-O based diet. CONCLUSION: Treatment with a balanced diet enriched in olive oil contributes to the liver recovery from a steatotic process. The PSC phenotype is a marker of this hepatic-recovery model.

Immunohistochemistry of neuronal nitric oxide synthase and protein nitration in the striatum of the aged rat.

To ascertain the possible implications of the nitric oxide (NO*) producing system in striatal senescence, and by using immunohistochemistry and image-processing approaches, we describe the presence of the enzyme nitric oxide synthase (NOS), the NADPH-diaphorase (NADPH-d) histochemical marker, and nitrotyrosine-derived complexes (N-Tyr) in the striatum of adult and aged rats. The results showed neuronal NOS immunoreactive (nNOS-IR) aspiny medium-sized neurons and nervous fibres in both age groups, with no variation in the percentage of immunoreactive area but a significant decrease in the intensity and in the number of somata with age, which were not related to the observed increase with age of the striatal bundles of the white matter. In addition, NADPH-d activity was detected in neurons with morphology similar to that of the nNOS-IR cells; a decrease in the percentage of area per field and in the number of cells, but an increase in the intensity of staining for the NADPH-d histochemical marker, were detected with age. The number of neuronal NADPH-d somata was higher than for the nNOS-IR ones in both age groups. Moreover, N-Tyr-IR complexes were observed in cells (neurons and glia) and fibres, with a significant increase in the percentage of the area of immunoreaction, related to the increase of white matter, but a decrease in intensity for the aged group. On the other hand, we did not detect the inducible isoform (iNOS) either in adult or in aged rats. Taken together, these results support the contention that NADPH-d staining is not such an unambiguous marker for nNOS, and that increased protein nitration may participate in striatal aging.

[Biological treatments for contaminated soils: hydrocarbon contamination. Fungal applications in bioremediation treatment]. / Tratamientos biológicos de suelos contaminados; contaminación por hidrocarburos. Aplicaciones de hongos en tratamientos de biorrecuperación.

Bioremediation is a spontaneous or controlled process in which biological, mainly microbiological, methods are used to degrade or transform contaminants to non or less toxic products, reducing the environmental pollution. The most important parameters to define a contaminated site are: biodegradability, contaminant distribution, lixiviation grade, chemical reactivity of the contaminants, soil type and properties, oxygen availability and occurrence of inhibitory substances. Biological treatments of organic contaminations are based on the degradative abilities of the microorganisms. Therefore the knowledge on the physiology and ecology of the biological species or consortia involved as well as the characteristics of the polluted sites are decisive factors to select an adequate biorremediation protocol. Basidiomycetes which cause white rot decay of wood are able to degrade lignin and a variety of environmentally persistent pollutants. Thus, white rot fungi and their enzymes are thought to be useful not only in some industrial process like biopulping and biobleaching but also in bioremediation. This paper provides a review of different aspects of bioremediation technologies and recent advances on ligninolytic metabolism research.

Glutathione S-transferase isoenzymatic response to aging in rat cerebral cortex and cerebellum.

Aging is associated with increased oxidant generation. One mechanism involved in the defense of oxidative products is the family of glutathione transferases (GST). We have analyzed the activity, distribution and expression of GSTP1 and GSTA4 isoenzymes in the cerebral cortex and cerebellum of young, adult and aged rats. The total GST activity, measured with the universal substrate 1-chloro-2,4-dinitrobenzene (CDNB), increased only with the maturation process; however GSTA4 activity, using the specific substrate 4-hydroxynonenal (HNE), did show an age-dependent increase in both brain regions. Cellular location of GSTA4 in astrocytes was not changed except for young cerebral cortex and adult/aged cerebellum that also showed immunoreactivity in layer III pyramidal neurons and Bergman radial glia, respectively. Distribution of GSTP1 was similar among groups and only an increased number of positive oligodendrocytes was found in the Purkinje and granular layer of adult/aged cerebellum. The GSTA4 and GSTP1 expression increased from young to adult/aged brain and GSTA4 even augmented in the aged cerebral cortex. These results suggest a GST isoenzymatic response with aging, but above all with the maturation process.

Age-related changes of the nitric oxide system in the rat brain.

This work examines the age-related changes of the NO pathway in the central nervous system (CNS), analyzing nitric oxide synthase (NOS) isoform expression, the level of nitrotyrosine-modified proteins, and the NOS activity in the cerebral cortex, decorticated brain (basal ganglia, thalamus, hypothalamus, tegtum and tegmentum) and cerebellum of young, adult and aged rats. Our data demonstrate that the different NOS isoforms are not uniformly expressed across the CNS. In this sense, the nNOS and eNOS isoenzymes are expressed mainly in the cerebellum and decorticated brain, respectively, while the iNOS isoenzyme shows the highest level in cerebellum. Concerning age, in the cerebral cortex nNOS significantly increased its expression only in adult animals; meanwhile, in the cerebellum the eNOS expression decreased whereas iNOS increased in adult and aged rats. No age-related changes in any isoform were found in decorticated brain. NOS activity, determined by nitrate plus nitrite quantification, registered the highest levels in the cerebellum, where the significant increase detected with aging was probably related to iNOS activity. The number of nitrotyrosine-modified immunoreactive bands differed among regions; thus, the highest number was detected in the decorticated brain while the cerebellum showed the least number of bands. Finally, bulk protein nitration increased in cerebral cortex only in adult animal. No changes were found in the decorticated brain, and the decrease detected in the cerebellum of aged animals was not significant. According to these results, the NO pathway is differently modified with age in the three CNS regions analyzed.