Hyperglycemia increases SCO-spondin and Wnt5a secretion into the cerebrospinal fluid to regulate ependymal cell beating and glucose sensing.

Hyperglycemia increases glucose concentrations in the cerebrospinal fluid (CSF), activating glucose-sensing mechanisms and feeding behavior in the hypothalamus. Here, we discuss how hyperglycemia temporarily modifies ependymal cell ciliary beating to increase hypothalamic glucose sensing. A high level of glucose in the rat CSF stimulates glucose transporter 2 (GLUT2)-positive subcommissural organ (SCO) cells to release SCO-spondin into the dorsal third ventricle. Genetic inactivation of mice GLUT2 decreases hyperglycemia-induced SCO-spondin secretion. In addition, SCO cells secrete Wnt5a-positive vesicles; thus, Wnt5a and SCO-spondin are found at the apex of dorsal ependymal cilia to regulate ciliary beating. Frizzled-2 and ROR2 receptors, as well as specific proteoglycans, such as glypican/testican (essential for the interaction of Wnt5a with its receptors) and Cx43 coupling, were also analyzed in ependymal cells. Finally, we propose that the SCO-spondin/Wnt5a/Frizzled-2/Cx43 axis in ependymal cells regulates ciliary beating, a cyclic and adaptive signaling mechanism to control glucose sensing.

Ascorbic acid and its transporter SVCT2, affect radial glia cells differentiation in postnatal stages.

Radial glia (RG) cells generate neurons and glial cells that make up the cerebral cortex. Both in rodents and humans, these stem cells remain for a specific time after birth, named late radial glia (lRG). The knowledge of lRG and molecules that may be involved in their differentiation is based on very limited data. We analyzed whether ascorbic acid (AA) and its transporter SVCT2, are involved in lRG cells differentiation. We demonstrated that lRG cells are highly present between the first and fourth postnatal days. Anatomical characterization of lRG cells, revealed that lRG cells maintained their bipolar morphology and stem-like character. When lRG cells were labeled with adenovirus-eGFP at 1 postnatal day, we detected that some cells display an obvious migratory neuronal phenotype, suggesting that lRG cells continue generating neurons postnatally. Moreover, we demonstrated that SVCT2 was apically polarized in lRG cells. In vitro studies using the transgenic mice SVCT2+/- and SVCT2tg (SVCT2-overexpressing mouse), showed that decreased SVCT2 levels led to accelerated differentiation into astrocytes, whereas both AA treatment and elevated SVCT2 expression maintain the lRG cells in an undifferentiated state. In vivo overexpression of SVCT2 in lRG cells generated cells with a rounded morphology that were migratory and positive for proliferation and neuronal markers. We also examined mediators that can be involved in AA/SVCT2-modulated signaling pathways, determining that GSK3-ß through AKT, mTORC2, and PDK1 is active in brains with high levels of SVCT2/AA. Our data provide new insights into the role of AA and SVCT2 in late RG cells.

In vivo subchronic effects of ciguatoxin-related compounds, reevaluation of their toxicity.

Ciguatoxins are marine compounds that share a ladder-shaped polyether structure produced by dinoflagellates of the genus Gambierdiscus and Fukuyoa, and include maitotoxins (MTX1 and MTX3), ciguatoxins (CTX3C) and analogues (gambierone), components of one of the most frequent human foodborne illness diseases known as ciguatera fish poisoning. This disease was previously found primarily in tropical and subtropical areas but nowadays, the dinoflagellates producers of ciguatoxins had spread to European coasts. One decade ago, the European Food Safety Authority has raised the need to complete the toxicological available data for the ciguatoxin group of compounds. Thus, in this work, the in vivo effects of ciguatoxin-related compounds have been investigated using internationally adopted guidelines for the testing of chemicals. Intraperitoneal acute toxicity was tested for maitotoxin 1 at doses between 200 and 3200 ng/kg and the acute oral toxicity of Pacific Ciguatoxin CTX3C at 330 and 1050 ng/kg and maitotoxin 1 at 800 ng/kg were also evaluated showing not effects on mice survival after a 96 h observation period. Therefore, for the following experiments the oral subchronic doses were between 172 and 1760 ng/kg for gambierone, 10 and 102 ng/kg for Pacific Ciguatoxin CTX3C, 550 and 1760 ng/kg for maitotoxin 3 and 800, 2560 and 5000 ng/kg for maitotoxin 1. The results presented here raise the need to reevaluate the in vivo activity of these agents. Although the intraperitoneal lethal dose of maitotoxin 1 is assumed to be 50 ng/kg, without chemical purity identifications and description of the bioassay procedures, in this work, an intraperitoneal lethal dose of 1107 ng/kg was obtained. Therefore, the data presented here highlight the need to use a common procedure and certified reference material to clearly establish the levels of these environmental contaminants in food.

Use of medical services in Chile: How sensitive are the results to different econometric models?

BACKGROUND: We compared different econometric specifications to model the use of medical services in Chile, focussing on visits to general practitioners and specialist physicians. METHODS: The evaluated models are the Poisson, Negative Binomial, Zero Inflated Poisson and Negative Binomial, two-step Hurdle model, sample-selection Poisson, and Latent Class model. These models were estimated using Chilean data for the years 2009 and 2015, separated by gender. RESULTS: Unlike previous literature that supported the use of the latent class model, our results show that the latent class model is not always the model with the best goodness of fit. Furthermore, the model with the best fit is not necessarily the model with the best predictive power. For instance, depending on the year and medical services, either the latent class model or the sample-selection Poisson model performs better than the other models. The results also show that the selection of the econometric model may have implications for the estimated influence that variables such as age, income, or affiliation to the public versus private sector have on the use of medical services. CONCLUSION: Using Chilean data, we have tested that the selection of an econometric method to model the use of medical services is not a problem with a unique answer. We recommend performing a sensitivity analysis of goodness of fit and predictive power between gender, healthcare services, or different years of datasets in future applications to be sure about the best model specification in each context.

Effects of precarious work on symptomatology of anxiety and depression in Chilean workers, a cross sectional study.

BACKGROUND: Precarious work is a broad definition for non-standard employment, often including unstable and insecure positions where workers permanently experience uncertainty; these types of jobs are growing steadily around the planet. Since the coup d'état in 1973, Chile has experienced a series of structural economic changes framed by neoliberal ideas cemented in the "Constitution of Pinochet." Precarious work in Chile is a direct consequence of these ideas. This multidimensional phenomenon has progressively been entering employment areas where it was not previously present. As a result, there has been a rise in work precarization and its full impact on health is not well known. The goal of this study was to estimate the association of work precariousness with mental health outcomes in Chilean workers. METHODS: Data were obtained from the Chilean Survey of Work and Health 2009-2010 (ENETS). Only valid records of salaried workers (excluding hourly-only or commission-only workers) in the private sector without missing values were included (n = 1900). After applying appropriate sampling weights, 1,461,727 workers were represented. Mental health was estimated as anxiety/depression levels using the 12-item General Health Questionnaire (GHQ-12). A multilevel multivariate generalized linear mixed model (GLMM) with negative binomial and log link distribution was used to study the association between precariousness and depression/anxiety. RESULTS: Looking at the overall precariousness scale (range from zero to four), we observed an increase of approximately 34% in the depression/anxiety score (scale range from 0 to 36) for every unit on the precarious work overall scale (Relative Risk = 1.34, 95% CI = 1.28, 1.42) controlling for age, sex, and occupational group. CONCLUSION: Precarious work was associated with anxiety and depression as measured with the 12-item General Health Questionnaire. Controlling for demographic variables changed neither the direction nor the magnitude of the association.

Dehydroascorbic acid, the oxidized form of vitamin C, improves renal histology and function in old mice.

Oxidative stress and inflammation are crucial factors that increase with age. In the progression of multiple age-related diseases, antioxidants and bioactive compounds have been recognized as useful antiaging agents. Oxidized or reduced vitamin C exerts different actions on tissues and has different metabolism and uptake. In this study, we analyzed the antiaging effect of vitamin C, both oxidized and reduced forms, in renal aging using laser microdissection, quantitative reverse-transcription polymerase chain reaction, and immunohistochemical analyses. In the kidneys of old SAM mice (10 months of age), a model of accelerated senescence, vitamin C, especially in the oxidized form (dehydroascorbic acid [DHA]) improves renal histology and function. Serum creatinine levels and microalbuminuria also decrease after treatment with a decline in azotemia. In addition, sodium-vitamin C cotransporter isoform 1 levels, which were increased during aging, are normalized. In contrast, the pattern of glucose transporter 1 expression is not affected by aging or vitamin C treatment. We conclude that oxidized and reduced vitamin C are potent antiaging therapies and that DHA reverses the kidney damage observed in senescence-accelerated prone mouse 8 to a greater degree.

Whole-body vibration and back pain-related work absence among heavy equipment vehicle mining operators.

OBJECTIVE: To determine the association between several whole-body vibration (WBV) exposure estimates and back pain-related work absence. METHODS: Exposures (based on the weighted daily root mean square acceleration, A(8); the daily vibration dose value, VDV(8); and the daily equivalent static compression dose, Sed(8)) of 2302 workers during 4 years were estimated using each worker's monthly vehicle operation records and WBV measurements from 11 different types of heavy equipment vehicles in a large coal mine. Company payroll data provided work absence during the concurrent 4 years of exposure. Cox regression models estimated the associations between the different WBV metrics and time to first work absence related to back pain. An adjusted R2 statistic provided a measure of model fit. RESULTS: All estimated metrics of WBV exposures were positively and significantly associated with back pain-related absence. HRs varied from 2.03 to 12.39 for every 0.21 m/s2 increase in the A(8)-based exposures; from 1.03 to 1.18 for every 1.72 m/s1.75 increase in VDV(8)-based exposures; and from 1.04 to 1.07 for every 0.06 MPa increase in Sed(8)-based exposures. Models using the estimated VDV(8) metric for the z axis fit the data best as measured by the R2 statistic. CONCLUSION: Higher WBV exposures were associated with back pain-related absences in this population, which appears after a few years of follow-up. Introducing controls to lower exposure levels may help reduce back pain-related work absences.

Why does the adverse effect of inappropriate MRI for LBP vary by geographic location? An exploratory analysis.

BACKGROUND: Early magnetic resonance imaging (eMRI) for nonspecific low back pain (LBP) not adherent to clinical guidelines is linked with prolonged work disability. Although the prevalence of eMRI for occupational LBP varies substantially among states, it is unknown whether the risk of prolonged disability associated with eMRI varies according to individual and area-level characteristics. The aim was to explore whether the known risk of increased length of disability (LOD) associated with eMRI scanning not adherent to guidelines for occupational LBP varies according to patient and area-level characteristics, and the potential reasons for any observed variations. METHODS: A retrospective cohort of 59,360 LBP cases from 49 states, filed between 2002 and 2008, and examined LOD as the outcome. LBP cases with at least 1 day of work disability were identified by reviewing indemnity service records and medical bills using a comprehensive list of codes from the International Classification of Diseases, Ninth Edition (ICD-9) indicating LBP or nonspecific back pain, excluding medically complicated cases. RESULTS: We found significant between-state variations in the negative impact of eMRI on LOD ranging from 3.4 days in Tennessee to 14.8 days in New Hampshire. Higher negative impact of eMRI on LOD was mainly associated with female gender, state workers' compensation (WC) policy not limiting initial treating provider choice, higher state orthopedic surgeon density, and lower state MRI facility density. CONCLUSION: State WC policies regulating selection of healthcare provider and structural factors affecting quality of medical care modify the impact of eMRI not adherent to guidelines. Targeted healthcare and work disability prevention interventions may improve work disability outcomes in patients with occupational LBP.

Aging Selectively Modulates Vitamin C Transporter Expression Patterns in the Kidney.

In the kidney, vitamin C is reabsorbed from the glomerular ultrafiltrate by sodium-vitamin C cotransporter isoform 1 (SVCT1) located in the brush border membrane of the proximal tubules. Although we know that vitamin C levels decrease with age, the adaptive physiological mechanisms used by the kidney for vitamin C reabsorption during aging remain unknown. In this study, we used an animal model of accelerated senescence (SAMP8 mice) to define the morphological alterations and aging-induced changes in the expression of vitamin C transporters in renal tissue. Aging induced significant morphological changes, such as periglomerular lymphocytic infiltrate and glomerular congestion, in the kidneys of SAMP8 mice, although no increase in collagen deposits was observed using 2-photon microscopy analysis and second harmonic generation. The most characteristic histological alteration was the dilation of intracellular spaces in the basolateral region of proximal tubule epithelial cells. Furthermore, a combination of laser microdissection, qRT-PCR, and immunohistochemical analyses allowed us to determine that SVCT1 expression specifically increased in the proximal tubules from the outer strip of the outer medulla (segment S3) and cortex (segment S2) during aging and that these tubules also express GLUT1. We conclude that aging modulates vitamin C transporter expression and that renal over-expression of SVCT1 enhances vitamin C reabsorption in aged animals that may synthesize less vitamin C. J. Cell. Physiol. 232: 2418-2426, 2017. © 2016 Wiley Periodicals, Inc.

Cytoarchitecture, Proliferative Activity and Neuroblast Migration in the Subventricular Zone and Lateral Ventricle Extension of the Adult Guinea Pig Brain.

In the mouse brain, neuroblasts generated in the subventricular zone (SVZ) migrate to the olfactory bulb (OB) through the rostral migratory stream (RMS). Although the RMS is not present in the human brain, a migratory pathway that is organized around a ventricular cavity that reaches the OB has been reported. A similar cavity, the lateral ventricle extension (LVE), is found in the adult guinea pig brain. Therefore, we analyzed cytoarchitecture, proliferative activity and precursor cell migration in the SVZ and LVE of 1-, 6- and 12-month-old guinea pigs. In young animals, we used confocal spectral and transmission electron microscopy to identify neuroblasts, astrocytes, and progenitor cells in the SVZ and LVE. Analysis of peroxidase diffusion demonstrated that the LVE was a continuous cavity lined by ependymal cells and surrounded by neuroblasts. Precursor cells were mostly located in the SVZ and migrated from the SVZ to the OB through the LVE. Finally, analysis of 6- and 12-month-old guinea pigs revealed that the LVE was preserved in older animals; however, the number of neurogenic cells was significantly reduced. Consequently, we propose that the guinea pig brain may be used as a new neurogenic model with increased similarity to humans, given that the LVE connects the LV with the OB, as has been described in humans, and that the LVE works a migratory pathway. Stem Cells 2016;34:2574-2586.

Age- and gender-specific associations between insomnia and falls in Boston Puerto Rican adults.

PURPOSE: This study evaluated the age- and gender-specific associations between insomnia and falls in community-dwelling Puerto Rican adults, independently of multiple covariates. METHODS: Cross-sectional data were collected from 954 Puerto Ricans, aged 46-79 years, in Boston, Massachusetts. In-person interviews were conducted to collect information on sociodemographics and lifestyle, mental status, medication use, comorbidities, sleep duration, insomnia symptoms, and falls and fractures. Blood and urine samples, and bone density measures were collected to assess C-reactive protein, serum interleukin-6, urinary cortisol, and bone mineral density. RESULTS: Multivariate robust Poisson regressions suggested that adults with insomnia had a 32 % increased likelihood of having falls (PR 1.32, p < 0.05), after adjustment for multiple covariates. Age and gender modified the effect of insomnia on risk of falls. Insomnia was significantly associated with higher risk of falls in adults of 60 years or older (PR 1.49, p < 0.05) and in women (PR 1.36, p < 0.05), but not in adults younger than 60 years or in men. Insomnia was not associated with recurrent falls or fractures. CONCLUSIONS: Age and gender need to be taken into account when considering treatment of insomnia in preventing geriatric falls. Well-designed evidence-based interventions to treat insomnia and improve sleep quality may reduce the risk of falls in this population.

Associations between safety climate and safety management practices in the construction industry.

BACKGROUND: Safety climate, a group-level measure of workers' perceptions regarding management's safety priorities, has been suggested as a key predictor of safety outcomes. However, its relationship with actual injury rates is inconsistent. We posit that safety climate may instead be a parallel outcome of workplace safety practices, rather than a determinant of workers' safety behaviors or outcomes. METHODS: Using a sample of 25 commercial construction companies in Colombia, selected by injury rate stratum (high, medium, low), we examined the relationship between workers' safety climate perceptions and safety management practices (SMPs) reported by safety officers. RESULTS: Workers' perceptions of safety climate were independent of their own company's implementation of SMPs, as measured here, and its injury rates. However, injury rates were negatively related to the implementation of SMPs. CONCLUSIONS: Safety management practices may be more important than workers' perceptions of safety climate as direct predictors of injury rates.

Regional socioeconomic disparities in outcomes for workers with low back pain in the United States.

BACKGROUND: Although regional socioeconomic (SE) factors have been associated with worse health outcomes, prior studies have not addressed important confounders or work disability. METHODS: A national sample of 59 360 workers' compensation (WC) cases to evaluate impact of regional SE factors on medical costs and length of disability (LOD) in occupational low back pain (LBP). RESULTS: Lower neighborhood median household incomes (MHI) and higher state unemployment rates were associated with longer LOD. Medical costs were lower in states with more workers receiving Social Security Disability, and in areas with lower MHI, but this varied in magnitude and direction among neighborhoods. Medical costs were higher in more urban, more racially diverse, and lower education neighborhoods. CONCLUSIONS: Regional SE disparities in medical costs and LOD occur even when health insurance, health care availability, and indemnity benefits are similar. Results suggest opportunities to improve care and disability outcomes through targeted health care and disability interventions.

Regenerative Therapies in Dry Eye Disease: From Growth Factors to Cell Therapy.

Dry eye syndrome is a complex and insidious pathology with a high level of prevalence among the human population and with a consequently high impact on quality of life and economic cost. Currently, its treatment is symptomatic, mainly based on the control of lubrication and inflammation, with significant limitations. Therefore, the latest research is focused on the development of new biological strategies, with the aim of regenerating affected tissues, or at least restricting the progression of the disease, reducing scar tissue, and maintaining corneal transparency. Therapies range from growth factors and cytokines to the use of different cell sources, in particular mesenchymal stem cells, due to their multipotentiality, trophic, and immunomodulatory properties. We will review the state of the art and the latest advances and results of these promising treatments in this pathology.

[Clinical features of major depressive disorders treated in secondary health care facilities in Chile]. / Características clínicas del trastorno depresivo mayor en tratamiento en el nivel secundario de atención.

BACKGROUND: Depression is considered the second leading cause of disability worldwide. AIM: To describe the clinical characteristics and the evolution of major depressive disorder (MDD) in secondary care. To evaluate the association between socio-demographic and clinic variables with the first or recurrent major depressive events (MDE). MATERIAL AND METHODS: Clinical features, treatment, remission and duration of MDE were evaluated during a follow up lasting 12 months in 112 participants aged 44 ± 15 years (79% women). Patients were assessed as outpatients every three months at three psychiatric care centers of Chile. Clinical interviews were carried out using DSM-IV diagnostic criteria checklists and the Hamilton Depression Scale was applied. RESULTS: Most patients were referred from primary care. The mean time lapse for referral to the secondary level was 10.8 months. Most patients had episodes that were recurrent, severe, with a high rate of psychosis, with suicide attempts and melancholic features and with psychiatric and medical comorbidities. Remission rate was 27.5%. In only 16 % of patients, the episode lasted six months or less. The group with recurrent episodes had different age, sex and clinical features. CONCLUSIONS: MDD treated at the secondary care level is severe and its symptoms are intense. The time lapse prior to referral was prolonged. Primary care management and referral of these patients should be studied more closely.

[Predictors of remission from major depressive disorder in secondary care]. / Predictores de remisión del trastorno depresivo mayor en tratamiento en el nivel secundario de atención.

Background The knowledge of predictive factors in depression should help to deal with the disease. Aim To assess potential predictors of remission of major depressive disorders (MDD) in secondary care and to propose a predictive model. Material and Methods A 12 month follow-up study was conducted in a sample of 112 outpatients at three psychiatric care centers of Chile, with baseline and quarterly assessments. Demographic, psychosocial, clinical and treatment factors as potential predictors, were assessed. A clinical interview with the checklist of DSM-IV diagnostic criteria, the Hamilton Depression Scale and the List of Threatening Experiences and Multidimensional Scale of Perceived Social Support were applied. Results The number of stressful events, perceived social support, baseline depression scores, melancholic features, time prior to beginning treatment at the secondary level and psychotherapeutic sessions were included in the model as predictors of remission. Sex, age, number of previous depressive episodes, psychiatric comorbidity and medical comorbidity were not significantly related with remission. Conclusions This model allows to predict depression score at six months with 70% of accuracy and the score at 12 months with 72% of accuracy.

SVCT2 transporter expression is post-natally induced in cortical neurons and its function is regulated by its short isoform.

Different studies have demonstrated the importance of micronutrients, such as vitamins, for normal adult brain function and development. Vitamin C is not synthesized in the brain, but high levels are detected in this organ because of the existence of specific uptake mechanisms, which concentrate ascorbic acid from the bloodstream to the cerebrospinal fluid and then into neurons and glial cells. Two different isoforms of sodium-vitamin C cotransporters (SVCT1 and SVCT2) have been cloned. SVCT2 expression has been observed in the adult hippocampus and cortical neurons by in situ hybridization. In addition, the localization of SVCT2 in the rat fetal brain has been studied by immunohistochemistry and in situ hybridization, demonstrating that SVCT2 is highly expressed in the ventricular and subventricular areas of the brain cortex. However, there are currently no immunohistochemical data regarding SVCT2 expression and function in the post-natal brain. Therefore, we analyzed SVCT2 expression in the developing brain cortex of mice, and demonstrated an increase in SVCT2 mRNA in mice at 1-15 days of age. The expression of a short isoform, SVCT2sh, was also detected within the same period. SVCT2 expression was concentrated in neurons within the inner layer of the brain cortex. Both SVCT2 isoforms were coexpressed in N2a cells to obtain functional data. Fluorescence resonance energy transfer analysis revealed a molecular interaction between SVCT2wt and SVCT2sh. Finally, differences in transport ratios suggested that SVCT2sh expression inhibited ascorbic acid uptake in N2a cells when both isoforms were coexpressed. The sodium-vitamin C cotransporter, SVCT2, is induced in neurons within the inner layer of the brain cortex during post-natal development, mainly in pyramidal cortex neurons. Two different isoforms, SVCT2wt and SVCT2sh, were detected. Using in vitro studies, we suggest a molecular interaction between SVCT2wt and SVCT2sh, which may regulate the affinity of vitamin C uptake.

Increased levels of tumour necrosis factor alpha (TNFα) but not transforming growth factor-beta 1 (TGFß1) are associated with the severity of congenital hydrocephalus in the hyh mouse.

AIMS: Here, we tested the hypothesis that glial responses via the production of cytokines such as transforming growth factor-beta 1 (TGFß1) and tumour necrosis factor alpha (TNFα), which play important roles in neurodegenerative diseases, are correlated with the severity of congenital hydrocephalus in the hyh mouse model. We also searched for evidence of this association in human cases of primary hydrocephalus. METHODS: Hyh mice, which exhibit either severe or compensated long-lasting forms of hydrocephalus, were examined and compared with wild-type mice. TGFß1, TNFα and TNFαR1 mRNA levels were quantified using real-time PCR. TNFα and TNFαR1 were immunolocalized in the brain tissues of hyh mice and four hydrocephalic human foetuses relative to astroglial and microglial reactions. RESULTS: The TGFß1 mRNA levels were not significantly different between hyh mice exhibiting severe or compensated hydrocephalus and normal mice. In contrast, severely hydrocephalic mice exhibited four- and two-fold increases in the mean levels of TNFα and TNFαR1, respectively, compared with normal mice. In the hyh mouse, TNFα and TNFαR1 immunoreactivity was preferentially detected in astrocytes that form a particular periventricular reaction characteristic of hydrocephalus. However, these proteins were rarely detected in microglia, which did not appear to be activated. TNFα immunoreactivity was also detected in the glial reaction in the small group of human foetuses exhibiting hydrocephalus that were examined. CONCLUSIONS: In the hyh mouse model of congenital hydrocephalus, TNFα and TNFαR1 appear to be associated with the severity of the disease, probably mediating the astrocyte reaction, neurodegenerative processes and ischaemia.

Diet-dependent modulation of hippocampal expression of endocannabinoid signaling-related proteins in cannabinoid antagonist-treated obese rats.

Diet-induced obesity produces changes in endocannabinoid signaling (ECS), influencing the regulation of energy homeostasis. Recently, we demonstrated that, in high-fat-diet-fed rats, blockade of CB1 receptor by AM251 not only reduced body weight but also increased adult neurogenesis in the hippocampus, suggesting an influence of diet on hippocampal cannabinoid function. To further explore the role of hippocampal ECS in high-fat-diet-induced obesity, we investigated whether the immunohistochemical expression of the enzymes that produce (diacylglycerol lipase alpha and N-acyl phosphatidylethanolamine phospholipase D) and degrade (monoacylglycerol lipase and fatty acid amino hydrolase) endocannabinoids may be altered in the hippocampus of AM251 (3 mg/kg)-treated rats fed three different diets: standard diet (normal chow), high-carbohydrate diet (70% carbohydrate) and high-fat diet (60% fat). Results indicated that AM251 reduced caloric intake and body weight gain, and induced a modulation of the expression of ECS-related proteins in the hippocampus of animals exposed to hypercaloric diets. These effects were differentially restricted to either the 2-arachinodoyl glycerol or anandamide signaling pathways, in a diet-dependent manner. AM251-treated rats fed the high-carbohydrate diet showed a reduction of the diacylglycerol lipase alpha : monoacylglycerol lipase ratio, whereas AM251-treated rats fed the high-fat diet showed a decrease of the N-acyl phosphatidylethanolamine phospholipase D : fatty acid amino hydrolase ratio. These results are consistent with the reduced levels of hippocampal endocannabinoids found after food restriction. Regarding the CB1 expression, AM251 induced specific changes focused in the CA1 stratum pyramidale of high-fat-diet-fed rats. These findings indicated that the cannabinoid antagonist AM251 modulates ECS-related proteins in the rat hippocampus in a diet-specific manner. Overall, these results suggest that the hippocampal ECS participates in the physiological adaptations to different caloric diets.

Insights into the effects of polygalacturonase FaPG1 gene silencing on pectin matrix disassembly, enhanced tissue integrity, and firmness in ripe strawberry fruits.

Antisense-mediated down-regulation of the fruit-specific polygalacturonase (PG) gene FaPG1 in strawberries (Fragaria×ananassa Duch.) has been previously demonstrated to reduce fruit softening and to extend post-harvest shelf life, despite the low PG activity detected in this fruit. The improved fruit traits were suggested to be attributable to a reduced cell wall disassembly due to FaPG1 silencing. This research provides empirical evidence that supports this assumption at the biochemical, cellular, and tissue levels. Cell wall modifications of two independent transgenic antisense lines that demonstrated a >90% reduction in FaPG1 transcript levels were analysed. Sequential extraction of cell wall fractions from control and ripe fruits exhibited a 42% decrease in pectin solubilization in transgenic fruits. A detailed chromatographic analysis of the gel filtration pectin profiles of the different cell wall fractions revealed a diminished depolymerization of the more tightly bound pectins in transgenic fruits, which were solubilized with both a chelating agent and sodium carbonate. The cell wall extracts from antisense FaPG1 fruits also displayed less severe in vitro swelling. A histological analysis revealed more extended cell-cell adhesion areas and an enhanced tissue integrity in transgenic ripe fruits. An immunohistological analysis of fruit sections using the JIM5 antibody against low methyl-esterified pectins demonstrated a higher labelling in transgenic fruit sections, whereas minor differences were observed with JIM7, an antibody that recognizes highly methyl-esterified pectins. These results support that the increased firmness of transgenic antisense FaPG1 strawberry fruits is predominantly due to a decrease in pectin solubilization and depolymerization that correlates with more tightly attached cell wall-bound pectins. This limited disassembly in the transgenic lines indicates that these pectin fractions could play a key role in tissue integrity maintenance that results in firmer ripe fruit.