Transcending the amyloid-beta dominance paradigm in Alzheimer's disease: An exploration of behavioural, metabolic, and gut microbiota phenotypes in 5xFAD mice.

The amyloid cascade hypothesis is widely accepted as an explanation for the neuropathological changes in Alzheimer's disease (AD). However, the role of amyloid-beta (Aß) as the sole cause of these changes is being questioned. Using the 5xFAD mouse model of AD, we investigated various factors contributing to neuropathology, including genetic load (heterozygous (HTZ) versus homozygous (HZ) condition), behavioural phenotype, neuropathology markers, metabolic physiology, and gut microbiota composition at early (5 months of age) and late (12 months of age) stages of disease onset, and considering both sexes. At 5 months of age, both HTZ and HZ mice exhibited hippocampal alterations associated with Aß accumulation, leading to increased neuroinflammation and disrupted PI3K-Akt pathway. However, only HZ mice showed cognitive impairment in the Y-maze and Morris water maze tests, worsening with age. Dysregulation of both insulin and insulin secretion-regulating GIP peptide were observed at 5 months of age, disappearing later. Circulating levels of metabolic-regulating hormones, such as Ghrelin and resisting helped to differentiates HTZ mice from HZ mice. Differences between HTZ and HZ mice were also observed in gut microbiota composition, disrupted intestinal barrier proteins, and increased proinflammatory products in the intestine. These findings suggest that cognitive impairment in 5xFAD mice may not solely result from Aß aggregation. Other factors, including altered PI3K-Akt signalling, disrupted insulin-linked metabolic pathways, and changes in gut microbiota, contribute to disease progression. Targeting Aß deposition alone may not suffice. Understanding AD pathogenesis and its multiple contributing factors is vital for effective therapies.

D-Chiro-Inositol Treatment Affects Oocyte and Embryo Quality and Improves Glucose Intolerance in Both Aged Mice and Mouse Models of Polycystic Ovarian Syndrome.

Polycystic ovarian syndrome (PCOS) is the main cause of female infertility. It is a multifactorial disorder with varying clinical manifestations including metabolic/endocrine abnormalities, hyperandrogenism, and ovarian cysts, among other conditions. D-Chiro-inositol (DCI) is the main treatment available for PCOS in humans. To address some of the mechanisms of this complex disorder and its treatment, this study examines the effect of DCI on reproduction during the development of different PCOS-associated phenotypes in aged females and two mouse models of PCOS. Aged females (8 months old) were treated or not (control) with DCI for 2 months. PCOS models were generated by treatment with dihydrotestosterone (DHT) on Days 16, 17, and 18 of gestation, or by testosterone propionate (TP) treatment on the first day of life. At two months of age, PCOS mice were treated with DCI for 2 months and their reproductive parameters analyzed. No effects of DCI treatment were produced on body weight or ovary/body weight ratio. However, treatment reduced the number of follicles with an atretic cyst-like appearance and improved embryo development in the PCOS models, and also increased implantation rates in both aged and PCOS mice. DCI modified the expression of genes related to oocyte quality, oxidative stress, and luteal sufficiency in cumulus-oocyte complexes (COCs) obtained from the aged and PCOS models. Further, the phosphorylation of AKT, a main metabolic sensor activated by insulin in the liver, was enhanced only in the DHT group, which was the only PCOS model showing glucose intolerance and AKT dephosphorylation. The effect of DCI in the TP model seemed mediated by its influence on oxidative stress and follicle insufficiency. Our results indicate that DCI works in preclinical models of PCOS and offer insight into its mechanism of action when used to treat this infertility-associated syndrome.

Role of the satiety factor oleoylethanolamide in alcoholism.

Oleoylethanolamide (OEA) is a satiety factor that controls motivational responses to dietary fat. Here we show that alcohol administration causes the release of OEA in rodents, which in turn reduces alcohol consumption by engaging peroxisome proliferator-activated receptor-alpha (PPAR-α). This effect appears to rely on peripheral signaling mechanisms as alcohol self-administration is unaltered by intracerebral PPAR-α agonist administration, and the lesion of sensory afferent fibers (by capsaicin) abrogates the effect of systemically administered OEA on alcohol intake. Additionally, OEA is shown to block cue-induced reinstatement of alcohol-seeking behavior (an animal model of relapse) and reduce the severity of somatic withdrawal symptoms in alcohol-dependent animals. Collectively, these findings demonstrate a homeostatic role for OEA signaling in the behavioral effects of alcohol exposure and highlight OEA as a novel therapeutic target for alcohol use disorders and alcoholism.

Plasma profile of pro-inflammatory cytokines and chemokines in cocaine users under outpatient treatment: influence of cocaine symptom severity and psychiatric co-morbidity.

The treatment for cocaine use constitutes a clinical challenge because of the lack of appropriate therapies and the high rate of relapse. Recent evidence indicates that the immune system might be involved in the pathogenesis of cocaine addiction and its co-morbid psychiatric disorders. This work examined the plasma pro-inflammatory cytokine and chemokine profile in abstinent cocaine users (n = 82) who sought outpatient cocaine treatment and age/sex/body mass-matched controls (n = 65). Participants were assessed with the diagnostic interview Psychiatric Research Interview for Substance and Mental Diseases according to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR). Tumor necrosis factor-alpha, chemokine (C-C motif) ligand 2/monocyte chemotactic protein-1 and chemokine (C-X-C motif) ligand 12 (CXCL12)/stromal cell-derived factor-1 (SDF-1) were decreased in cocaine users, although all cytokines were identified as predictors of a lifetime pathological use of cocaine. Interleukin-1 beta (IL-1ß), chemokine (C-X3-C motif) ligand 1 (CX3CL1)/fractalkine and CXCL12/SDF-1 positively correlated with the cocaine symptom severity when using the DSM-IV-TR criteria for cocaine abuse/dependence. These cytokines allowed the categorization of the outpatients into subgroups according to severity, identifying a subgroup of severe cocaine users (9-11 criteria) with increased prevalence of co-morbid psychiatric disorders [mood (54%), anxiety (32%), psychotic (30%) and personality (60%) disorders]. IL-1ß was observed to be increased in users with such psychiatric disorders relative to those users with no diagnosis. In addition to these clinical data, studies in mice demonstrated that plasma IL-1ß, CX3CL1 and CXCL12 were also affected after acute and chronic cocaine administration, providing a preclinical model for further research. In conclusion, cocaine exposure modifies the circulating levels of pro-inflammatory mediators. Plasma cytokine/chemokine monitoring could improve the stratification of cocaine consumers seeking treatment and thus facilitate the application of appropriate interventions, including management of heightened risk of psychiatric co-morbidity. Further research is necessary to elucidate the role of the immune system in the etiology of cocaine addiction.

Hydroxytyrosol Linoleoyl Ether Ameliorates Metabolic-Associated Fatty Liver Disease Symptoms in Obese Zucker Rats.

A main hepatic consequence of obesity is metabolic-associated fatty liver disease (MAFLD), currently treated by improving eating habits and administrating fibrates yet often yielding suboptimal outcomes. Searching for a new therapeutic approach, we aimed to evaluate the efficacy of hydroxytyrosol linoleoyl ether (HTLE), a dual Ppar-α agonist/Cb1 antagonist with inherent antioxidant properties, as an antisteatotic agent. Using lean and obese Zucker rats, they were administrated daily doses of HTLE (3 mg/kg) over a 15-day period, evaluating its safety profile, pharmacokinetics, impact on body weight, hepatic fat content, expression of key enzymes involved in lipogenesis/fatty acid oxidation, and antioxidant capacity. HTLE decreased the body weight and food intake in both rat genotypes. Biochemical analysis demonstrated a favorable safety profile for HTLE along with decreased concentrations of urea, total cholesterol, and aspartate aminotransferase AST transaminases in plasma. Notably, HTLE exhibited potent antisteatotic effects in obese rats, evidenced by a decrease in liver fat content and downregulation of lipogenesis-related enzymes, alongside increased expression of proteins controlling lipid oxidation. Moreover, HTLE successfully counteracted the redox imbalance associated with MAFLD in obese rats, attenuating lipid peroxidation and replenishing both glutathione levels and the overall antioxidant. Our findings highlight the effectiveness of triple-action strategies in managing MAFLD effectively. Based on our results in the Zucker rat model, HTLE emerges as a promising candidate with triple functionality as an anorexigenic, antisteatotic, and antioxidant agent, offering potential relief from MAFLD symptoms associated with obesity while exhibiting minimal side effects. In conclusion, our study positions HTLE as a highly promising compound for therapeutic intervention in MAFLD treatment, warranting further exploration in clinical trials.

IL-6 cooperates with peroxisome proliferator-activated receptor-α-ligands to induce liver fatty acid binding protein (LFABP) up-regulation.

BACKGROUND: LFABP plays a critical role in the uptake and intracellular transport of fatty acids (FA) and other peroxisome proliferator-activated receptor alpha (PPARα) ligands. PPARα activation by PPARα ligands bound to LFABP results in gene expression of FA oxidation enzymes and de novo LFABP. The cytokine IL-6 is involved in regulating liver lipid oxidation. AIMS: To study the ability of IL-6 to modulate the expression of the LFABP in hepatocytes. METHODS: HepG2 and mouse primary hepatocytes were used to test LFABP mRNA and protein expression after IL-6 and PPARα-ligand treatments. Mice lacking IL-6 and wild-type C57Bl/6 were subjected to a fasting/re-feeding cycle to monitor hepatic LFABP mRNA kinetics after food intake. RESULTS: In hepatocyte cultures, IL-6 treatment stimulated a LFABP mRNA sustained expression. Combined treatment of IL-6 plus PPARα ligands further enhanced LFABP gene and protein expression. In contrast, pretreatment with the PPARα-antagonist GW-6471 prevented the up-regulation of LFABP mRNA induced by IL-6 in the late phase of LFABP kinetics. Furthermore, the up-regulation of LFABP mRNA observed in the liver of wild-type mice 8 h after re-feeding was absent in mice lacking IL-6. CONCLUSIONS: IL-6 induces LFABP kinetics in hepatocytes and is partially dependent on PPARα. The maximum increase in LFABP expression occurs when the stimulation with IL-6 and PPARα-ligands takes place simultaneously. The in vivo results indicate a postprandial regulation of LFABP that correlates with the presence of IL-6. These effects may have important implications in the postprandial increase in FA uptake and intracellular trafficking in the liver.

Administration of Linoleoylethanolamide Reduced Weight Gain, Dyslipidemia, and Inflammation Associated with High-Fat-Diet-Induced Obesity.

Acylethanolamides (NAEs) are bioactive lipids derived from diet fatty acids that modulate important homeostatic functions, including appetite, fatty acid synthesis, mitochondrial respiration, inflammation, and nociception. Among the naturally circulating NAEs, the pharmacology of those derived from either arachidonic acid (Anandamide), oleic acid (OEA), and palmitic acid (PEA) have been extensively characterized in diet-induced obesity. For the present work, we extended those studies to linoleoylethanolamide (LEA), one of the most abundant NAEs found not only in plasma and body tissues but also in foods such as cereals. In our initial study, circulating concentrations of LEA were found to be elevated in overweight humans (body mass index (BMI, Kg/m2) > 25) recruited from a representative population from the south of Spain, together with AEA and the endocannabinoid 2-Arachidonoyl glycerol (2-AG). In this population, LEA concentrations correlated with the circulating levels of cholesterol and triglycerides. In order to gain insight into the pharmacology of LEA, we administered it for 14 days (10 mg/kg i.p. daily) to obese male Sprague Dawley rats receiving a cafeteria diet or a standard chow diet for 12 consecutive weeks. LEA treatment resulted in weight loss and a reduction in circulating triglycerides, cholesterol, and inflammatory markers such as Il-6 and Tnf-alpha. In addition, LEA reduced plasma transaminases and enhanced acetyl-CoA-oxidase (Acox) and Uncoupling protein-2 (Ucp2) expression in the liver of the HFD-fed animals. Although the liver steatosis induced by the HFD was not reversed by LEA, the overall data suggest that LEA contributes to the homeostatic signals set in place in response to diet-induced obesity, potentially contributing with OEA to improve lipid metabolism after high fat intake. The anti-inflammatory response associated with its administration suggests its potential for use as a nutrient supplement in non-alcoholic steatohepatitis.

Adiponectin promoter activator NP-1 reduces body weight and hepatic steatosis in high-fat diet-fed animals.

Enhancement of adiponectin level has been shown to have beneficial effects, including antiobesity, antidiabetic, and hepatoprotective effects. This evidence supports the therapeutic utility of adiponectin in complicated obesity. The present study characterized the in vivo effects of sustained adiponectin release by NP-1, a new class of thiazol derivative that increases adiponectin levels. Acute administration of NP-1 reduced feeding, increased plasma adiponectin, and improved insulin sensitivity without inducing malaise, as revealed by conditioned taste aversion studies. Short-term (7 days) treatment with NP-1 also reduced feeding and body weight gain and increased phosphorylation of AMPK in muscle, a main intracellular effector of adiponectin. NP-1 was also evaluated in diet-induced obesity, and adult male Wistar rats were fed two different types of diet: a standard high-carbohydrate/low-fat diet (SD) and a high-fat diet (HFD). Once obesity was established, animals were treated daily with NP-1 (5 mg/kg) for 14 consecutive days. Chronic NP-1 induced body weight loss and reduction of food intake and resulted in both a marked decrease in liver steatosis and an improvement of biochemical indexes of liver damage in HFD-fed rats. However, a marked induction of tolerance in adiponectin gene transcription and release was observed after chronic NP-1 with respect to the acute actions of this drug. The present results support the role of adiponectin signaling in diet-induced obesity and set in place a potential use of compounds able to induce adiponectin release for the treatment of obesity and nonalcoholic fatty liver, with the limits imposed by the induction of pharmacological tolerance.

d-Pinitol promotes tau dephosphorylation through a cyclin-dependent kinase 5 regulation mechanism: A new potential approach for tauopathies?

BACKGROUND AND PURPOSE: Recent evidence links brain insulin resistance with neurodegenerative diseases, where hyperphosphorylated tau protein contributes to neuronal cell death. In the present study, we aimed to evaluate if d-pinitol inositol, which acts as an insulin sensitizer, affects the phosphorylation status of tau protein. EXPERIMENTAL APPROACH: We studied the pharmacological effect of d-pinitol on insulin signalling and tau phosphorylation in the hippocampus of Wistar and Zucker rats. To this end, we evaluated by western blotting the Akt pathway and its downstream proteins as being one of the main insulin-mediator pathways. Also, we explored the functional status of additional kinases phosphorylating tau, including PKA, ERK1/2, AMPK and CDK5. We utilized the 3xTg mouse model as a control for tauopathy, since it carries tau mutations that promote phosphorylation and aggregation. KEY RESULTS: Surprisingly, we discovered that oral d-pinitol treatment lowered tau phosphorylation significantly, but not through the expected kinase GSK-3 regulation. An extensive search for additional kinases phosphorylating tau revealed that this effect was mediated through a mechanism dependent on the reduction of the activity of the CDK5, affecting both its p35 and p25 subunits. This effect disappeared in leptin-deficient Zucker rats, uncovering that the association of leptin deficiency, obesity, dyslipidaemia and hyperinsulinaemia abrogates d-pinitol actions on tau phosphorylation. The 3xTg mice confirmed d-pinitol effectiveness in a genetic AD-tauopathy. CONCLUSION AND IMPLICATIONS: The present findings suggest that d-pinitol, by regulating CDK5 activity through a decrease of CDK5R1, is a potential drug for developing treatments for neurological disorders such as tauopathies.

Endocrine and Metabolic Impact of Oral Ingestion of a Carob-Pod-Derived Natural-Syrup-Containing D-Pinitol: Potential Use as a Novel Sweetener in Diabetes.

The widespread use of added sugars or non-nutritive sweeteners in processed foods is a challenge for addressing the therapeutics of obesity and diabetes. Both types of sweeteners generate health problems, and both are being blamed for multiple complications associated with these prevalent diseases. As an example, fructose is proven to contribute to obesity and liver steatosis, while non-nutritive sweeteners generate gut dysbiosis that complicates the metabolic control exerted by the liver. The present work explores an alternative approach for sweetening through the use of a simple carob-pod-derived syrup. This sweetener consists of a balanced mixture of fructose (47%) and glucose (45%), as sweetening sugars, and a functional natural ingredient (D-Pinitol) at a concentration (3%) capable of producing active metabolic effects. The administration of this syrup to healthy volunteers (50 g of total carbohydrates) resulted in less persistent glucose excursions, a lower insulin response to the hyperglycemia produced by its ingestion, and an enhanced glucagon/insulin ratio, compared to that observed after the ingestion of 50 g of glucose. Daily administration of the syrup to Wistar rats for 10 days lowered fat depots in the liver, reduced liver glycogen, promoted fat oxidation, and was devoid of toxic effects. In addition, this repeated administration of the syrup improved glucose handling after a glucose (2 g/kg) load. Overall, this alternative functional sweetener retains the natural palatability of a glucose/fructose syrup while displaying beneficial metabolic effects that might serve to protect against the progression towards complicated obesity, especially the development of liver steatosis.

Pharmacokinetics and Endocrine Effects of an Oral Dose of D-Pinitol in Human Fasting Healthy Volunteers.

The present study characterizes the oral pharmacokinetics of D-Pinitol, a natural insulin mimetic inositol, in human healthy volunteers (14 males and 11 females). D-Pinitol absorption was studied in (a) subjects receiving a single oral dose of 15 mg/kg (n = 10), or (b) 5 mg/kg pure D-Pinitol (n = 6), and (c) subjects receiving D-Pinitol as part of carbohydrate-containing carob pods-derived syrup with a 3.2% D-Pinitol (Dose of 1600 mg/subject, n = 9). The volunteers received a randomly assigned single dose of either D-Pinitol or carob pod-derived syrup. Blood samples were collected at 0, 15, 30, 45, 60, 90, 120, 180, 240, 360 and 1440 min after intake. Plasma concentration of D-Pinitol was measured and pharmacokinetic parameters obtained. The data indicate that when given alone, the oral absorption of D-Pinitol is dose-dependent and of extended duration, with a Tmax reached after almost 4 h, and a half-life greater than 5 h. When the source of D-Pinitol was a carob pods-derived syrup, Cmax was reduced to 40% of the expected based on the data of D-Pinitol alone, suggesting a reduced absorption probably because of competition with monosaccharide transport. In this group, Tmax was reached before that of D-Pinitol alone, but the estimated half-life remained the same. In the D-Pinitol groups, plasma concentrations of glucose, insulin, glucagon, ghrelin, free fatty acids, and pituitary hormones were additionally measured. A dose of 15 mg/kg of D-Pinitol did not affect glucose levels in healthy volunteers, but reduced insulin and increased glucagon and ghrelin concentrations. D-Pinitol did not increase other hormones known to enhance plasma glucose, such as cortisol or GH, which were surprisingly reduced after the ingestion of this inositol. Other pituitary hormones (gonadotropins, prolactin, and thyroid-stimulating hormone) were not affected after D-Pinitol ingestion. In a conclusion, D-Pinitol is absorbed through the oral route, having an extended half-life and displaying the pharmacological profile of an endocrine pancreas protector, a pharmacological activity of potential interest for the treatment or prevention of insulin resistance-associated conditions.

Discovery of V-0219: A Small-Molecule Positive Allosteric Modulator of the Glucagon-Like Peptide-1 Receptor toward Oral Treatment for "Diabesity".

Peptidic agonists of the glucagon-like peptide-1 receptor (GLP-1R) have gained a prominent role in the therapy of type-2 diabetes and are being considered for reducing food intake in obesity. Potential advantages of small molecules acting as positive allosteric modulators (PAMs) of GLP-1R, including oral administration and reduced unwanted effects, could improve the utility of this class of drugs. Here, we describe the discovery of compound 9 (4-{[1-({3-[4-(trifluoromethyl)phenyl]-1,2,4-oxadiazol-5-yl}methyl)piperidin-3-yl]methyl}morpholine, V-0219) that exhibits enhanced efficacy of GLP-1R stimulation, subnanomolar potency in the potentiation of insulin secretion, and no significant off-target activities. The identified GLP-1R PAM shows a remarkable in vivo activity, reducing food intake and improving glucose handling in normal and diabetic rodents. Enantioselective synthesis revealed oral efficacy for (S)-9 in animal models. Compound 9 behavior bolsters the interest of a small-molecule PAM of GLP-1R as a promising therapeutic approach for the increasingly prevalent obesity-associated diabetes.

Activation of PI3K/Akt Signaling Pathway in Rat Hypothalamus Induced by an Acute Oral Administration of D-Pinitol.

D-Pinitol (DPIN) is a natural occurring inositol capable of activating the insulin pathway in peripheral tissues, whereas this has not been thoroughly studied in the central nervous system. The present study assessed the potential regulatory effects of DPIN on the hypothalamic insulin signaling pathway. To this end we investigated the Phosphatidylinositol-3-kinase (PI3K)/Protein Kinase B (Akt) signaling cascade in a rat model following oral administration of DPIN. The PI3K/Akt-associated proteins were quantified by Western blot in terms of phosphorylation and total expression. Results indicate that the acute administration of DPIN induced time-dependent phosphorylation of PI3K/Akt and its related substrates within the hypothalamus, indicating an activation of the insulin signaling pathway. This profile is consistent with DPIN as an insulin sensitizer since we also found a decrease in the circulating concentration of this hormone. Overall, the present study shows the pharmacological action of DPIN in the hypothalamus through the PI3K/Akt pathway when giving in fasted animals. These findings suggest that DPIN might be a candidate to treat brain insulin-resistance associated disorders by activating insulin response beyond the insulin receptor.

Palmitoleoylethanolamide Is an Efficient Anti-Obesity Endogenous Compound: Comparison with Oleylethanolamide in Diet-Induced Obesity.

Obesity is currently a major epidemic in the developed world. However, we lack a wide range of effective pharmacological treatments and therapies against obesity, and those approved are not devoid of adverse effects. Dietary components such as palmitoleic acid have been proposed to improve metabolic disbalance in obesity, although the mechanisms involved are not well understood. Both palmitoleic acid (POA) and oleic acid (OA) can be transformed in N-acylethanolamines (NAEs), mediating the effects of dietary POA and OA. To test this hypothesis, here, we study the effects on food intake and body weight gain of palmitoleylethanolamide (POEA) and the OA-derived NAE analogue, oleoylethanolamide (OEA), in Sprague-Dawley rats with a hypercaloric cafeteria diet (HFD). Plasma biochemical metabolites, inflammatory mediators, and lipogenesis-associated liver protein expression were also measured. The results indicate that POEA is able to improve health status in diet-induced obesity, decreasing weight, liver steatosis, inflammation, and dyslipemia. The action of POEA was found to be almost identical to that of OEA, which is an activator of the nuclear peroxisome proliferator receptor alpha (PPARα), and it is structurally related to POEA. These results suggest that the dietary administration of either POA or POEA might be considered as nutritional intervention as complementary treatment for complicated obesity in humans.

Peroxisome Proliferator-Activated Receptors: Experimental Targeting for the Treatment of Inflammatory Bowel Diseases.

The peroxisome proliferator-activated receptors (PPARs) are a group of nuclear receptor proteins that promote ligand-dependent transcription of target genes that regulate energy production, lipid metabolism, and inflammation. The PPAR superfamily comprises three subtypes, PPARα, PPARγ, and PPARß/δ, with differential tissue distributions. In addition to their different roles in the regulation of energy balance and carbohydrate and lipid metabolism, an emerging function of PPARs includes normal homeostasis of intestinal tissue. PPARα activation represses NF-κB signaling, which decreases the inflammatory cytokine production by different cell types, while PPARγ ligands can inhibit activation of macrophages and the production of inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and Il-1ß. In this regard, the anti-inflammatory responses induced by PPAR activation might restore physiopathological imbalances associated with inflammatory bowel diseases (IBD). Thus, PPARs and their ligands have important therapeutic potential. This review briefly discusses the roles of PPARs in the physiopathology and therapies of the most important IBDs, ulcerative colitis (UC), and Crohn's disease (CD), as well some new experimental compounds with PPAR activity as promising drugs for IBD treatment.

D-Pinitol from Ceratonia siliqua Is an Orally Active Natural Inositol That Reduces Pancreas Insulin Secretion and Increases Circulating Ghrelin Levels in Wistar Rats.

To characterize the metabolic actions of D-Pinitol, a dietary inositol, in male Wistar rats, we analyzed its oral pharmacokinetics and its effects on (a) the secretion of hormones regulating metabolism (insulin, glucagon, IGF-1, ghrelin, leptin and adiponectin), (b) insulin signaling in the liver and (c) the expression of glycolytic and neoglucogenesis enzymes. Oral D-Pinitol administration (100 or 500 mg/Kg) resulted in its rapid absorption and distribution to plasma and liver compartments. Its administration reduced insulinemia and HOMA-IR, while maintaining glycaemia thanks to increased glucagon activity. In the liver, D-Pinitol reduced the key glycolytic enzyme pyruvate kinase and decreased the phosphorylation of the enzymes AKT and GSK-3. These observations were associated with an increase in ghrelin concentrations, a known inhibitor of insulin secretion. The profile of D-Pinitol suggests its potential use as a pancreatic protector decreasing insulin secretion through ghrelin upregulation, while sustaining glycaemia through the liver-based mechanisms of glycolysis control.

Cocaine-induced changes in CX3CL1 and inflammatory signaling pathways in the hippocampus: Association with IL1ß.

Cocaine induces neuroinflammatory response and interleukin-1 beta (IL1ß) is suggested a final effector for many cocaine-induced inflammatory signals. Recently, the chemokine fractalkine (CX3CL1) has been reported to regulate hippocampus-dependent neuroinflammation and synaptic plasticity via CX3C-receptor 1 (CX3CR1), but little is known about the impact of cocaine. This study is mainly focused on the characterization of CX3CL1, IL1ß and relevant inflammatory signal transduction pathways in the hippocampus in acute and repeated cocaine-treated male mice. Complementarily, the rewarding properties of cocaine were also assessed in Cx3cr1-knockout (KO) mice using a conditioned place preference (CPP). We observed significant increases in CX3CL1 and IL1ß concentrations after cocaine, although repeated cocaine produced an enhancement of CX3CL1 concentrations. CX3CL1 and IL1ß concentrations were positively correlated in acute (r = +0.61) and repeated (r = +0.82) cocaine-treated mice. Inflammatory signal transduction pathways were assessed. Whereas acute cocaine-treated mice showed transient increases in p-ERK1/2/ERK1/2 and p-p65/p65 NFκB ratios after cocaine injection, repeated cocaine-treated mice showed transient increases in p-ERK1/2/ERK1/2, p-p38/p38 MAPK, p-NFκB p65/NF-κB p65 and p-CREB/CREB ratios. Baseline p-p38/p38 MAPK and p-CREB/CREB ratios were downregulated in repeated cocaine-treated mice. Regarding the cocaine-induced CPP, Cx3cr1-KO mice showed a notably impaired extinction but no differences during acquisition and reinstatement. These results indicate that cocaine induces alterations in CX3CL1 concentrations, which are associated with IL1ß concentrations, and activates convergent inflammatory pathways in the hippocampus. Furthermore, the CX3CL1/CX3CR1 signaling could mediate the processes involved in the extinction of cocaine-induced CPP.

Regulation of brain anandamide by acute administration of ethanol.

The endogenous cannabinoid acylethanolamide AEA (arachidonoylethanolamide; also known as anandamide) participates in the neuroadaptations associated with chronic ethanol exposure. However, no studies have described the acute actions of ethanol on AEA production and degradation. In the present study, we investigated the time course of the effects of the intraperitoneal administration of ethanol (4 g/kg of body mass) on the endogenous levels of AEA in central and peripheral tissues. Acute ethanol administration decreased AEA in the cerebellum, the hippocampus and the nucleus accumbens of the ventral striatum, as well as in plasma and adipose tissue. Parallel decreases of a second acylethanolamide, PEA (palmitoylethanolamide), were observed in the brain. Effects were observed 45-90 min after ethanol administration. In vivo studies revealed that AEA decreases were associated with a remarkable inhibition of the release of both anandamide and glutamate in the nucleus accumbens. There were no changes in the expression and enzymatic activity of the main enzyme that degrades AEA, the fatty acid amidohydrolase. Acute ethanol administration did not change either the activity of N-acyltransferase, the enzyme that catalyses the synthesis of the AEA precursor, or the expression of NAPE-PLD (N-acylphosphatidylethanolamine-hydrolysing phospholipase D), the enzyme that releases AEA from membrane phospholipid precursors. These results suggest that receptor-mediated release of acylethanolamide is inhibited by the acute administration of ethanol, and that this effect is not derived from increased fatty acid ethanolamide degradation.

The adiponectin promoter activator NP-1 induces high levels of circulating TNFα and weight loss in obese (fa/fa) Zucker rats.

Chronic NP-1 administration reduces body weight and hepatic steatosis despite induction of tolerance in adiponectin gene transcription with respect to the acute actions of this drug. This study explored the hypothesis that NP-1 could exert these effects through mechanisms independent of adiponectin. To this aim, we took advantage of the Zucker (fa/fa) rat model, which exhibits obesity, fatty liver and elevated leptin and adiponectin levels. Body weight and food intake were reduced after chronic NP-1 treatment. Plasma TNFα concentrations were elevated but no increase in adiponectin was found. Even so, NP-1 ameliorated fatty liver and corrected dyslipidemia by mechanisms probably associated with reduced feeding, transcription of Cpt1 and down-regulation of Hmgcr-CoA expression. In brown fat tissue NP-1 increased Dnmt1 (inhibitor of Adipoq) while it reduced Ucp1 expression and heat production, which excludes thermogenesis as a mechanism of the NP-1 slimming effect. The anti-obesity action of chronic NP-1 administration might be mediated by TNFα, which is known to have anorectic actions in the hypothalamus and to regulate both Dmnt1 and Ucp1 expression in adipose tissues. This finding opens up the possibility of using NP-1-mediated TNFα-induced weight loss as an innovative treatment of complicated obesity under strict pharmacologic control.

Acetaminophen-Induced Liver Injury Alters the Acyl Ethanolamine-Based Anti-Inflammatory Signaling System in Liver.

Protective mechanisms against drug-induced liver injury are actively being searched to identify new therapeutic targets. Among them, the anti-inflammatory N-acyl ethanolamide (NAE)-peroxisome proliferators activated receptor alpha (PPARα) system has gained much interest after the identification of its protective role in steatohepatitis and liver fibrosis. An overdose of paracetamol (APAP), a commonly used analgesic/antipyretic drug, causes hepatotoxicity, and it is being used as a liver model. In the present study, we have analyzed the impact of APAP on the liver NAE-PPARα system. A dose-response (0.5-5-10-20 mM) and time-course (2-6-24 h) study in human HepG2 cells showed a biphasic response, with a decreased PPARα expression after 6-h APAP incubation followed by a generalized increase of NAE-PPARα system-related components (PPARα, NAPE-PLD, and FAAH), including the NAEs oleoyl ethanolamide (OEA) and docosahexaenoyl ethanolamide, after a 24-h exposure to APAP. These results were partially confirmed in a time-course study of mice exposed to an acute dose of APAP (750 mg/kg). The gene expression levels of Pparα and Faah were decreased after 6 h of treatment and, after 24 h, the gene expression levels of Nape-pld and Faah, as well as the liver levels of OEA and palmitoyl ethanolamide, were increased. Repeated APAP administration (750 mg/kg/day) up to 4 days also decreased the expression levels of PPARα and FAAH, and increased the liver levels of NAEs. A resting period of 15 days completely restored these impairments. Liver immunohistochemistry in a well-characterized human case of APAP hepatotoxicity confirmed PPARα and FAAH decrements. Histopathological and hepatic damage (Cyp2e1, Caspase3, αSma, Tnfα, and Mcp1)-related alterations observed after repeated APAP administration were aggravated in the liver of Pparα-deficient mice. Our results demonstrate that the anti-inflammatory NAE-PPARα signaling system is implicated in liver toxicity after exposure to APAP overdose, and may contribute to its recovery through a long-term time-dependent response.