Sub-chronic celecoxib prevents soluble beta amyloid-induced depressive-like behaviour in rats.

BACKGROUND: Depression and Alzheimer's disease (AD) are co-morbid conditions. Neuropsychiatric symptoms have been reported as prodromal symptoms of AD-like dementia and soluble forms of beta amyloid peptide (Aß), the main constituent of insoluble plaques typical of AD brains, have been implicated in such an effect. We have previously shown that intracerebral injection of Aß can evoke a depressive-like state in rats, accompanied by neurochemical and neuroendocrine alterations reminiscent of depressive symptoms in humans. AD and depression are crucially linked by neuroinflammation and cyclooxygenase II (COX-2) enzyme involvement is an intriguing field of research. Indeed, its pharmacological inhibition has shown both antidepressant and Aß modulating effects. METHODS: Male rats were exposed to sub-chronic celecoxib (15 mg/kg/day sc for 8 days), a selective COX-2 inhibitor or vehicle (saline), starting from the day before central intracerebroventricular injection of Aß peptide (5µL of 4 µM solution or vehicle for sham). Animals were tested for depressive-like behaviour by using the forced swimming test paradigm and prefrontal serotonin (5-HT) content and plasma Aß levels were further evaluated. RESULTS: We found that celecoxib treatment prevented the pro-depressive effects induced by Aß. Moreover, it also prevented the reduction in 5-HT content in prefrontal cortex of Aß-treated rats and decreased their plasma Aß levels. CONCLUSIONS: Taken together, our data indicate that celecoxib could be a suitable pharmaceutical tool for the treatment of depressive state related to increased Aß levels.

Micellar electrokinetic chromatography with laser induced fluorescence detection shows increase of putrescine in erythrocytes of Parkinson's disease patients.

A highly sensitive method was developed to measure putrescine by micellar electrokinetic chromatography with laser induced fluorescence detection with excellent linearity in the 1 nM to 3 µM range. The technique was tested on a drop of blood from Parkinson's disease patients obtained by finger prick. The results showed a statistically significant increase of putrescine in the erythrocytes compared to controls and a non-significant increase in plasma. This high level of putrescine does not constitute by itself proof that putrescine and polyamines are directly related to Parkinson's disease. However, the present results and several others addressed in the discussion suggest that these compounds might be causally involved in the pathophysiology of Parkinson's disease. In addition, the analytical method reported here may help to find new biomarkers for many diseases including Parkinson's disease.

N-3 PUFA diet enrichment prevents amyloid beta-induced depressive-like phenotype.

Among neuropsychiatric diseases, depression is one of the most prevalent. Many pathologies have been indicated as comorbid with depression and in particular, neurodegenerative disorders such as Alzheimer's diseases (AD). In this regard, several evidences endorse a strong relationship between depression and AD, so much that this mental illness has been proposed either as a risk factor for AD or as a prodromic AD phase. Furthermore, amyloid beta (Aß) peptide, the main constituent of amyloid plaques commonly considered the principal hallmark of AD brains, has been shown to be increased, in its soluble form, in depressed patients. Accordingly, we have previously found that Aß, intracerebroventricularly (i.c.v.) injected, is able to evoke a depressive-like profile in rats accompanied by low cortical serotonin and reduced neurotrophin content. Taking into account the great increase in AD and depression prevalence, many environmental factors have been under study, particularly dietary factors, and the role of polyunsaturated fatty acids (PUFA) is becoming central in this field of research. Thus, aim of the present study was to evaluate the neurobehavioral effects of lifelong exposure to either n-3 PUFA rich or n-3 PUFA poor diet after Aß central administration. Results showed that n-3 PUFA enriched diet prevented the Aß- induced depressive-like behaviors, as reveled by the reduction in the immobility time in the FST test. Furthermore, n-3 PUFA rich diet exposure reverted also serotonin and neurotrophin level reduction in prefrontal cortex of Aß treated rats. Taken together, our data support the concept that supplementation of diet with n-3 PUFA represents a valid approach to reduce the risk of developing depressive symptoms, as well as reducing the risk of Aß-related pathologies, such as AD.

Cardiac morphofunctional characteristics of transgenic rats with overexpression of the bradykinin B1 receptor in the endothelium.

Our aim was to evaluate whether endothelial overexpressing of the bradykinin B1 receptor could be associated with altered left ventricular and myocardial performance. Echocardiography and hemodynamic were employed to assess left ventricular morphology and function in Sprague Dawley transgenic rats overexpressing the endothelial bradykinin B1 receptor (Tie2B1 rats). The myocardial inotropism was evaluated on papillary muscles contracting in vitro. In Tie2B1 animals, an enlarged left ventricular cavity and lower fractional shortening coupled with a lower rate of pressure change values indicated depressed left ventricular performance. Papillary muscle mechanics revealed that both Tie2B1 and wild-type rat groups had the same contractile capacities under basal conditions; however, in transgenic animals, there was accentuated inotropism due to post-pause potentiation. Following treatment with the Arg(9)-BK agonist, Tie2B1 papillary muscles displayed a reduction in myocardial inotropism. Endothelial B1 receptor overexpression has expanded the LV cavity and worsened its function. There was an exacerbated response of papillary muscle in vitro to a prolonged resting pause, and the use of a B1 receptor agonist impairs myocardial inotropism.

The NADPH oxidase NOX2 as a novel biomarker for suicidality: evidence from human post mortem brain samples.

Recent evidence points towards a role of oxidative stress in suicidality. However, few studies were carried out on the sources of reactive oxygen species (ROS) in subjects with suicidal behaviour. We have previously demonstrated that the NADPH oxidase NOX2-derived oxidative stress has a major role in the development of neuropathological alterations observed in an animal model of psychosis. Here, we investigated the possible increase in NOX2 in post mortem brain samples of subjects who died by asphyctic suicide (AS) compared with controls (CTRL) and subjects who died by non-suicidal asphyxia (NSA). We found that NOX2 expression was significantly higher in the cortex of AS subjects than in the other two experimental groups. NOX2 immunostaining was mainly detected in GABAergic neurons, with a minor presence of NOX2-positive-stained cells in glutamatergic and dopaminergic neurons, as well as astrocytes and microglia. A sustained increase in the expression of 8-hydroxy-2'-deoxyguanosine, an indirect marker of oxidative stress, was also detected in the cortex of AS subjects, compared with CTRL and NSA subjects. A significant elevation in cortical interleukin-6 immunoreactivity in AS subjects suggested an involvement of cytokine-associated molecular pathways in NOX2 elevations. Our results suggest that the increase in NOX2-derived oxidative stress in the brain might be involved in the neuropathological pathways leading to suicidal behaviour. These results may open innovative insights in the identification of new pathogenetic and necroscopic biomarkers, predictive for suicidality and potentially useful for suicide prevention.

Value of real-time gastric juice analysis in upper gastrointestinal endoscopy.

AIM: Esophagogastroduodenoscopy (EGDS) cannot identify microscopic lesions. We determined the contribution of real-time gastric juice analysis in detecting lesions non-detectable with the simple endoscopic inspection. METHODS: Endoscopy, histology and gastric juice analysis were performed in 216 patients. We assessed six diagnostic strategies: EGDS (strategy-1), EGDS with antral biopsies (hematoxylin-eosin staining) in hypochlorhydrics (strategy-2) or all patients (strategy-3), EGDS with antral and fundic biopsies (hematoxylin-eosin staining) in hypochlorhydrics (strategy-4) or all patients (strategy-5), EGDS with antral and fundic biopsies (hematoxylin-eosin + immunohistochemical staining) in hypochlorhydrics (strategy-6). Then, we determined how many of the pathological conditions identified by the complete histological evaluation would have been detected by each strategy. RESULTS: In total, 220 pathological conditions were identified. Hypochlorhydria was correlated (r=0.67; P<0.01) with histological lesions (85% lesions were detected in hypochlorhydrics) and high ammonium levels, with H.pylori infection (r=0.69; P<0.01). Strategy-1 identified only 5% conditions, while strategies 3 and 5 detected 68.6% and 83.2% conditions, respectively. Strategies 2, 4 and 6 (based on gastric juice analysis) yielded detection rates (61.4%, 75.5%, 90.9%) similar to or better than those of strategies 3 and 5. CONCLUSION: Real-time gastric juice analysis provided information about the presence of gastric lesions in an otherwise "normal" stomach at EGDS. It improved the diagnostic yield and optimized resource utilization without any additional effort by the endoscopist.

p73 regulates serine biosynthesis in cancer.

Activation of serine biosynthesis supports growth and proliferation of cancer cells. Human cancers often exhibit overexpression of phosphoglycerate dehydrogenase (PHGDH), the metabolic enzyme that catalyses the reaction that diverts serine biosynthesis from the glycolytic pathway. By refueling serine biosynthetic pathways, cancer cells sustain their metabolic requirements, promoting macromolecule synthesis, anaplerotic flux and ATP. Serine biosynthesis intersects glutaminolysis and together with this pathway provides substrates for production of antioxidant GSH. In human lung adenocarcinomas we identified a correlation between serine biosynthetic pathway and p73 expression. Metabolic profiling of human cancer cell line revealed that TAp73 activates serine biosynthesis, resulting in increased intracellular levels of serine and glycine, associated to accumulation of glutamate, tricarboxylic acid (TCA) anaplerotic intermediates and GSH. However, at molecular level p73 does not directly regulate serine metabolic enzymes, but transcriptionally controls a key enzyme of glutaminolysis, glutaminase-2 (GLS-2). p73, through GLS-2, favors conversion of glutamine in glutamate, which in turn drives the serine biosynthetic pathway. Serine and glutamate can be then employed for GSH synthesis, thus the p73-dependent metabolic switch enables potential response against oxidative stress. In knockdown experiment, indeed, TAp73 depletion completely abrogates cancer cell proliferation capacity in serine/glycine-deprivation, supporting the role of p73 to help cancer cells under metabolic stress. These findings implicate p73 in regulation of cancer metabolism and suggest that TAp73 influences glutamine and serine metabolism, affecting GSH synthesis and determining cancer pathogenesis.

Functions of TAp63 and p53 in restraining the development of metastatic cancer.

Many tumours harbour mutations in the p53 tumour-suppressor gene that result in the expression of a mutant p53 protein. This mutant p53 protein has, in most cases, lost wild-type transcriptional activity and can also acquire novel functions in promoting invasion and metastasis. One of the mechanisms underlying these novel functions involves the ability of the mutant p53 to interfere with other transcription factors, including the p53 family protein TAp63. To investigate whether simultaneous depletion of both p53 and TAp63 can recapitulate the effect of mutant p53 expression in vivo, we used a mouse model of pancreatic cancer in which the expression of mutant p53 resulted in the rapid appearance of primary tumours and metastases. As shown previously, loss of one allele of wild-type (WT) p53 accelerated tumour development. A change of one WT p53 allele into mutant p53 did not further accelerate tumour development, but did promote the formation of metastasis. By contrast, loss of TAp63 did not significantly accelerate tumour development or metastasis. However, simultaneous depletion of p53 and TAp63 led to both rapid tumour development and metastatic potential, although the incidence of metastases remained lower than that seen in mutant p53-expressing tumours. TAp63/p53-null cells derived from these mice also showed an enhanced ability to scatter and invade in tissue culture as was observed in mutant p53 cells. These data suggest that depletion of TAp63 in a p53-null tumour can promote metastasis and recapitulate-to some extent-the consequences of mutant p53 expression.

Perendoscopic real-time assessment of pH improves detection of gastric preneoplastic conditions.

AIM: Gastric juice may constitute a precious source of clinicopathological information. We assessed the usefulness of real-time, perendoscopic, gastric juice pH determination in identifying preneoplastic conditions of the stomach, that often escape the mere endoscopic evaluation. METHODS: The study included 245 patients (115M; 130F; age 47±17). In each of them perendoscopic gastric juice pH was assessed by means of an innovative device, the Endofaster, and the results were correlated with histological evaluation (H&E, immunohistochemistry, argyrophil stains), and gastric acid secretion (BAO-PAO), and serum gastrin levels. The conditions evaluated were: atrophy, intestinal metaplasia, endocrine cell hyperplasia, hypergastrinemia. RESULTS: A total of 136 pathological conditions were detected and these resulted to be correlated with pH (r=0.67; P<0.01). The rate of pathological conditions was low in normochlorhydric patients (14.1%); most of these conditions were concentrated in patients with hypochlorhydria (85.9%) (P<0.001). Specifically, the number of patients with one or more pathological conditions increased proportionately with the rise in pH levels. An inverse correlation was detected between gastric juice pH and basal acid output (BAO) (r=-0.72; P<0.01). Endoscopic feature was normal/mild in most of patients with pathological conditions. CONCLUSION: Hypochlorhydria is a sensitive indicator of gastric risk conditions. Perendoscopic real-time assessment of pH can improve and extend optical analysis by allowing the detection of pathological conditions (either preneoplastic or not) that often escape diagnosis because not correlated with specific endoscopic pattern.

Metabolic effects of TiO2 nanoparticles, a common component of sunscreens and cosmetics, on human keratinocytes.

The long-term health risks of nanoparticles remain poorly understood, which is a serious concern given their prevalence in the environment from increased industrial and domestic use. The extent to which such compounds contribute to cellular toxicity is unclear, and although it is known that induction of oxidative stress pathways is associated with this process, the proteins and the metabolic pathways involved with nanoparticle-mediated oxidative stress and toxicity are largely unknown. To investigate this problem further, the effect of TiO2 on the HaCaT human keratinocyte cell line was examined. The data show that although TiO2 does not affect cell cycle phase distribution, nor cell death, these nanoparticles have a considerable and rapid effect on mitochondrial function. Metabolic analysis was performed to identify 268 metabolites of the specific pathways involved and 85 biochemical metabolites were found to be significantly altered, many of which are known to be associated with the cellular stress response. Importantly, the uptake of nanoparticles into the cultured cells was restricted to phagosomes, TiO2 nanoparticles did not enter into the nucleus or any other cytoplasmic organelle. No other morphological changes were detected after 24-h exposure consistent with a specific role of mitochondria in this response.

Senescence and aging: the critical roles of p53.

p53 functions as a transcription factor involved in cell-cycle control, DNA repair, apoptosis and cellular stress responses. However, besides inducing cell growth arrest and apoptosis, p53 activation also modulates cellular senescence and organismal aging. Senescence is an irreversible cell-cycle arrest that has a crucial role both in aging and as a robust physiological antitumor response, which counteracts oncogenic insults. Therefore, via the regulation of senescence, p53 contributes to tumor growth suppression, in a manner strictly dependent by its expression and cellular context. In this review, we focus on the recent advances on the contribution of p53 to cellular senescence and its implication for cancer therapy, and we will discuss p53's impact on animal lifespan. Moreover, we describe p53-mediated regulation of several physiological pathways that could mediate its role in both senescence and aging.

PIR2/Rnf144B regulates epithelial homeostasis by mediating degradation of p21WAF1 and p63.

ΔNp63 is a transcription factor that is critical for the development of stratified epithelia and is overexpressed or amplified in >80% of squamous cell carcinomas (SCCs). We identified the RING finger E3 ubiquitin ligase PIR2/Rnf144b as a direct transcriptional target of ΔNp63α and showed that its expression parallels that of ΔNp63α in keratinocytes, SCC cell lines and SCCs. We used primary keratinocytes as a model system to investigate the function of PIR2/Rnf144b in stratified epithelia. Depletion of PIR2/Rnf144b severely impaired keratinocyte proliferation and differentiation, associated with accumulation of p21(WAF1/CIP1); a known target of PIR2/Rnf144b. More importantly, we found that PIR2/Rnf144b binds and mediates proteasomal degradation of ΔNp63α, generating a hitherto unknown auto-regulatory feedback loop. These findings substantiate PIR2/Rnf144b as a potentially critical component of epithelial homeostasis, acting downstream of ΔNp63α to regulate cellular levels of p21(WAF1/CIP1) and ΔNp63α.

Changes in GABAergic inputs in the paraventricular nucleus maintain sympathetic vasomotor tone in chronic heart failure.

The paraventricular nucleus (PVN) of the hypothalamus is an important region of the brain involved in the regulation of sympathetic vasomotor tone. Accumulating evidence supports the idea that a change in hypothalamic γ-aminobutyric acid (GABA)-ergic inhibitory and glutamatergic excitatory inputs contribute to the exacerbated sympathetic drive in chronic heart failure (HF). The purpose of this study was to determine whether a possible imbalance between glutamatergic and GABAergic inputs to the PVN contributes to increased sympathetic outflow in HF in two different sympathetic territories. Renal (RSNA) and splanchnic sympathetic nerve activity (SSNA), mean arterial blood pressure (MAP) and heart rate were recorded from urethane-anesthetized HF or sham rats. The NMDA-glutamate and GABA-A receptor densities within the PVN were quantified in HF and sham rats by autoradiography. Bilateral microinjection of kynurenic acid (4nmol) into the PVN decreased MAP and RSNA and SSNA in HF but not in sham rats. Furthermore, in response to GABA-A blockade in the PVN by bicuculline (400 pmol), hypertension and SSNA were reduced in HF compared to sham. The quantification of ionotropic NMDA receptors and GABA-A receptors in the PVN showed a significant reduction of GABA-A in HF rats; however, the NMDA density in the PVN did not differ between groups. Thus, this study provides evidence that the sympathoexcitation is maintained by an imbalance between GABAergic and glutamatergic inputs in the PVN in HF. The reduced GABAergic input results in relatively augmented glutamatergic actions in the PVN of HF rats.

Hemodynamic and thermoregulatory effects of xylazine-ketamine mixture persist even after the anesthetic stage in rats / Efeitos hemodinâmicos e termorregulatórios da mistura cetamina-xilasina persistem mesmo após o período anestésico em ratos

The xylazine-ketamine mixture (KX) is an anesthetic approach commonly administered to assess cardiovascular function in rodents. This study aimed to examine if the cardiovascular and thermoregulatory effects of KX could persist after the anesthetic state ceased in rats. Male Wistar rats were anesthetized with K (50mg/kg) X (10mg/kg) through the intra-peritoneal route. Hemodynamic and thermoregulatory repercussions were evaluated in animals in awake state, during an anesthetic depth and after complete recovery of anesthetized state. KX was efficient to significantly induce deep anesthesia in all rats after 10min. A complete recovery of anesthetized state was observed only after 210min. Compared with preanesthetic state and control animals that received no drug, KX induced a significant reduction of systolic and diastolic blood pressure at 10min. Hypotension was more prominent at 150min. The heart rate was also significantly reduced after 10 min of KX and the highest magnitude of bradycardia was observed at 30min. In addition, rectal temperature was markedly decreased at 30min of KX and the higher reduction occurred at 150min. The hemodynamic and thermoregulatory effects of KX were maintained even after complete anesthetic recovery.

Objetivou-se com este estudo avaliar a persistência dos efeitos cardiovasculares e termorregulatórios da associação cetamina e xilasina (CX) mesmo após o período anestésico em ratos. Ratos Wistar machos foram anestesiados com cetamina 50mg/kg e xilasina 10mg/kg, por via intra-peritoneal. As repercussões hemodinâmica e termorregulatória foram avaliadas com os animais acordados, durante o período anestésico e após recuperação completa da anestesia. A CX foi eficiente em induzir significante regime anestésico em todos os ratos após 10min. A recuperação completa do estado de anestesia foi observada somente após 210min. Comparado com o estado pré-anestésico e com animais controles, que não receberam anestesia, a CX induziu significativa redução das pressões sistólica e diastólica aos 10min. A hipotensão foi mais evidente aos 150min após CX. A frequência cardíaca também foi significativamente reduzida com 10min de CX e a bradicardia foi mais acentuada aos 30min. A temperatura retal foi reduzida aos 30min, sendo mais acentuada após 150min de anestesia. Os efeitos hemodinâmicos e termorregulatórios da CX persistem mesmo após completa recuperação anestésica.

[5 days Cefaclor vs. 10 days amoxicillin/clavulanate in the treatment of childhood streptococcal pharyngitis. Data from a randomized clinical trial]. / Efficacia di Cefaclor 5 giorni vs. amoxicillina-acido clavulanico 10 giorni, nella terapia della faringotonsillite streptococcia del bambino. Risultati di uno studio clinico randomizzato.

AIM: The duration of therapy represents a fundamental aspect in the compliance to the therapy of child pathologies, such as pharyngotonsillitis, treated with oral therapy. Although penicillin and amoxicillin are the first choice antibiotics in the case of a child suffering from pharyngotonsillitis with the proven presence of Group A ß-hemolytic Streptococcus (GAS), the number of orally administered doses and 10 days of therapy, considerably lower the compliance. METHODS: An open phase IV randomized multicenter clinical trial was conducted in parallel groups, involving 49 family pediatrician (FP), distributed over the entire national territory, enrolling 435 children suffering from GAS-FT. 210 children received Cefaclor, 50 mg/kg/day, administered twice daily for five days, whilst 213 children received amoxicillin/clavulanate 40 mg/kg/day administered twice daily for 10 days. RESULTS: The results showed percentages of eradication of 88.4% for the Cefaclor group and 94.3% for the amoxicillin/clavulanate group, and a positive clinical judgement of 92.3% for the Cefaclor group and 96.6% for the amoxicillin/clavulanate group. The two arms of the study did not have any significant statistical differences, neither for the eradication, nor for the clinical judgement nor for the reduction of the Milano Score between the beginning and the end of treatment, with a P=0.042 for amoxicillin/clavulanate for eradication. CONCLUSION: This study confirms that the administration of Cefaclor for five days during GAS-FT has the same efficacy as a 10-day therapy with amoxicillin/clavulanate, with a clearly different compliance.

Extraction, characterization and in vivo neuromodulatory activity of phytosterols from microalga Dunaliella tertiolecta.

In recent years, a great deal of research has been devoted to identify new natural sources of phytosterols and to improve methods for their recovery and purification. In this regard, unexplored natural sources of bioactive ingredients are gaining much attention since they can lead to the isolation of new compounds or bioactivities. The field of available natural sources has been further increased by including algae and, even more interestingly, microalgae. In the present study, a multidisciplinary approach has been used considering, in an integrated view, extraction, chemical composition and bioactivity of phytosterols from the microalga Dunaliella tertiolecta. A novel methodology to extract, separate and characterize microalgal-derived phytosterols has been developed. In addition, recoverable and reusable eluents have been selected in order to reduce the quantities of employed organic solvents. Finally, we addressed the question whether orally administered phytosterols reach the brain and if those interfere with the major neurotransmitter systems, such as the dopaminergic, serotoninergic and noradrenergic ones, in several brain areas of rats. Flash Liquid Chromatography has been used to separate the Total Sterol (TS) fraction, composed of twelve sterols, with a purity of 97.87% and a recovery percentage of 98%, while the "flash version" of Silver Ion Liquid Chromatography has been used to purify the most abundant phytosterols in TS, (22E,24R)- methylcholesta-5,7,22-trien-3ß-ol (ergosterol) and (22E,24R)-ethylcholesta-5,7,22-trien-3ß-ol (7-dehydroporiferasterol), with a purity of 97.4%. These two combined methods did not need sophisticated technologies but only cheap laboratory supplies. Moreover, the possibility of recovering and recycling the solvents used as eluents made it a cleaner process. Finally, for the first time, a neuromodulatory action of Dunaliella tertiolecta-derived phytosterols has been found in selective brain areas of rats.

Estrous cycle affects the neurochemical and neurobehavioral profile of carvacrol-treated female rats.

Carvacrol is the major constituent of essential oils from aromatic plants. It showed antimicrobial, anticancer and antioxidant properties. Although it was approved for food use and included in the chemical flavorings list, no indication on its safety has been estimated. Since the use of plant extracts is relatively high among women, aim of this study was to evaluate carvacrol effects on female physiology and endocrine profiles by using female rats in proestrus and diestrus phases. Serotonin and metabolite tissue content in prefrontal cortex and nucleus accumbens, after carvacrol administration (0.15 and 0.45g/kg p.o.), was measured. Drug effects in behavioral tests for alterations in motor activity, depression, anxiety-related behaviors and endocrine alterations were also investigated. While in proestrus carvacrol reduced serotonin and metabolite levels in both brain areas, no effects were observed in diestrus phase. Only in proestrus phase, carvacrol induced a depressive-like behavior in forced swimming test, without accompanying changes in ambulation. The improvement of performance in FST after subchronic treatment with fluoxetine (20mg/kg) suggested a specific involvement of serotonergic system. No differences were found across the groups with regard to self-grooming behavior. Moreover, in proestrus phase, carvacrol reduced only estradiol levels without binding hypothalamic estradiol receptors. Our study showed an estrous-stage specific effect of carvacrol on depressive behaviors and endocrine parameters, involving serotonergic system. Given the wide carvacrol use not only as feed additive, but also as cosmetic essence and herbal remedy, our results suggest that an accurate investigation on the effects of its chronic exposure is warranted.

Soluble beta amyloid(1-42): a critical player in producing behavioural and biochemical changes evoking depressive-related state?

BACKGROUND AND PURPOSE: Depression is common in early phases of Alzheimer's disease (AD) and may represent prodromal symptoms of dementia. Recent reports suggest that early memory deficits and neuropsychiatric symptoms are caused by soluble rather than aggregated betaamyloid (Abeta). Thus, we investigated the effects of soluble Abeta(1-42) on working memory and depressive/anxiety-related behaviour in rats and on 5-hydroxytryptaminergic neurotransmission and neurotrophin content in various brain regions. EXPERIMENTAL APPROACH: Behavioural reactivity to novel object recognition, open field, elevated plus maze and forced swimming test were assessed 7 days after i.c.v. injection of Abeta(1-42) or its vehicle. BDNF (brain-derived neurotrophic factor) and NGF (nerve growth factor) mRNA and protein levels and 5-hydroxytriptamine (5-HT) content were measured in the prefrontal cortex (PFC), striatum (STR) and nucleus accumbens (NAc). KEY RESULTS: Abeta(1-42) did not affect the ability to distinguish between familiar and novel objects, but Abeta-treated rats exhibited an increase in forced swimming immobility. No differences were revealed between experimental groups in the elevated plus maze test or in self-grooming (evaluated in the open field). In the PFC, but not STR or NAc, Abeta-injected rats exhibited a selective reduction in 5-HT content, BDNF and NGF expression. CONCLUSIONS AND IMPLICATIONS: Our data suggest that soluble Abeta-treated rats have a depressive, but not anxiogenic-like, profile, accompanied by brain region-dependent alterations in the expression of neurotrophins and 5-hydroxytryptaminergic neurotransmission. Hence, these alterations induced by soluble Abeta might be sensitive indicators of early phases of AD and possible risk factors for the expression of neuropsychiatric symptoms in AD.

Intramyocardial transplantation of fibroblasts expressing vascular endothelial growth factor attenuates cardiac dysfunction.

In this study, we analyzed whether transplantation of cardiac fibroblasts (CFs) expressing vascular endothelial growth factor (VEGF) mitigates cardiac dysfunction after myocardial infarction (MI) in rats. First, we observed that the transgene expression lasts longer (45 vs 7 days) when fibroblasts are used as vectors compared with myoblasts. In a preventive protocol, induction of cardiac neovascularization accompanied by reduction in myocardial scar area was observed when cell transplantation was performed 1 week before ischemia/reperfusion and the animals analyzed 3 weeks later. Finally, the therapeutic efficacy of this approach was tested injecting cells in a fibrin biopolymer, to increase cardiac retention, 24 h post-MI. After 4 weeks, an increase in neovascularization and a decrease in myocardial collagen were observed only in rats that received cells expressing VEGF. Basal indirect or direct hemodynamic measurements showed no differences among the groups whereas under pharmacological stress, only the group that received cells expressing VEGF showed a significant reduction in end-diastolic pressure and improvement in stroke volume and cardiac work. These results indicate that transplantation of CFs expressing VEGF using fibrin biopolymer induces neovascularization and attenuates left ventricle fibrosis and cardiac dysfunction in ischemic heart.

The negative inotropic action of canrenone is mediated by L-type calcium current blockade and reduced intracellular calcium transients.

BACKGROUND AND PURPOSE: Adding spironolactone to standard therapy in heart failure reduces morbidity and mortality, but the underlying mechanisms are not fully understood. We analysed the effect of canrenone, the major active metabolite of spironolactone, on myocardial contractility and intracellular calcium homeostasis. EXPERIMENTAL APPROACH: Left ventricular papillary muscles and cardiomyocytes were isolated from male Wistar rats. Contractility of papillary muscles was assessed with force transducers, Ca(2+) transients by fluorescence and Ca(2+) fluxes by electrophysiological techniques. KEY RESULTS: Canrenone (300-600 micromol L(-1)) reduced developed tension, maximum rate of tension increase and maximum rate of tension decay of papillary muscles. In cardiomyocytes, canrenone (50 micromol L(-1)) reduced cell shortening and L-type Ca(2+) channel current, whereas steady-state activation and inactivation, and reactivation curves were unchanged. Canrenone also decreased the Ca(2+) content of the sarcoplasmic reticulum, intracellular Ca(2+) transient amplitude and intracellular diastolic Ca(2+) concentration. However, the time course of [Ca(2+)](i) decline during transients evoked by caffeine was not affected by canrenone. CONCLUSION AND IMPLICATIONS: Canrenone reduced L-type Ca(2+) channel current, amplitude of intracellular Ca(2+) transients and Ca(2+) content of sarcoplasmic reticulum in cardiomyocytes. These changes are likely to underlie the negative inotropic effect of canrenone.