PPARα/γ, adiponectin, and GLUT4 overexpression induced by moronic acid methyl ester influenced glucose and triglyceride levels of experimental diabetic mice.

The current study aimed to determine the antidiabetic and antidyslipidemic activities of moronic acid methyl ester (1) (compound 1) by in vivo, in vitro, in silico, and molecular biology studies. Compound 1 was evaluated to establish its dose-dependent antidiabetic and antihyperglycemic (50 mg/kg) activities, in diabetic and normoglycemic male CD1 mice, respectively. Also, compound 1 was subjected to a subacute study (50 mg/kg per day for 8 days) to determine blood biochemical profiles and the expression of protein tyrosine phosphatase 1B (PTP-1B), glucose transporter type 4 (GLUT4), peroxisome proliferator-activated receptor α (PPAR-α), PPAR-γ, adiponectin, interleukin-1ß (IL-1ß), and monocyte chemoattractant protein 1 (MCP-1) in adipose tissue of animals after treatment. Different doses in acute administration of compound 1 decreased glycemia (p < 0.05) compared with vehicle, showing greater effectiveness in the range 50-160 mg/kg. Also, the oral glucose tolerance test showed that compound 1 induced a significant antihyperglycemic action by opposing the hyperglycemic peak (p < 0.05). Moreover, compound 1 subacute administration decreased glucose and triglyceride levels after treatment (p < 0.05); while the expression of PPAR-α and PPAR-γ, adiponectin, and GLUT4 displayed an increase (p < 0.05) compared with the diabetic control group. In conclusion, compound 1 showed antihyperglycemic, antidiabetic, and antidyslipidemic effects in normal and diabetic mice, probably due to insulin sensitization through increased mRNA expression of GLUT4, PPAR-α, PPAR-γ, and adiponectin genes.

Angiotensin II Inhibits Insulin Receptor Signaling in Adipose Cells.

Angiotensin II (Ang II) is a critical regulator of insulin signaling in the cardiovascular system and metabolic tissues. However, in adipose cells, the regulatory role of Ang II on insulin actions remains to be elucidated. The effect of Ang II on insulin-induced insulin receptor (IR) phosphorylation, Akt activation, and glucose uptake was examined in 3T3-L1 adipocytes. In these cells, Ang II specifically inhibited insulin-stimulated IR and insulin receptor substrate-1 (IRS-1) tyrosine-phosphorylation, Akt activation, and glucose uptake in a time-dependent manner. These inhibitory actions were associated with increased phosphorylation of the IR at serine residues. Interestingly, Ang II-induced serine-phosphorylation of IRS was not detected, suggesting that Ang II-induced desensitization begins from IR regulation itself. PKC inhibition by BIM I restored the inhibitory effect of Ang II on insulin actions. We also found that Ang II promoted activation of several PKC isoforms, including PKCα/ßI/ßII/δ, and its association with the IR, particularly PKCßII, showed the highest interaction. Finally, we also found a similar regulatory effect of Ang II in isolated adipocytes, where insulin-induced Akt phosphorylation was inhibited by Ang II, an effect that was prevented by PKC inhibitors. These results suggest that Ang II may lead to insulin resistance through PKC activation in adipocytes.

Potential role of angiotensin-(1-7) in the improvement of vascular insulin sensitivity after a bout of exercise.

NEW FINDINGS: What is the central question of this study? What is the mechanism by which a bout of exercise increases subsequent insulin-stimulated vasodilatation? What is the main finding and its importance? Angiotensin-(1-7) through the Mas receptor participates in enhanced insulin-induced vasorelaxation after a bout of exercise in healthy rats. This new potential role of angiotensin-(1-7) could help in understanding how physical activity improves vascular insulin sensitivity in normal and insulin-resistant states. ABSTRACT: Exercise increases insulin-stimulated vasodilatation, but the mechanisms involved are unclear. This study was performed to investigate the possible involvement of angiotensin-(1-7) (Ang-(1-7)), a vasoactive peptide of the renin-angiotensin system (RAS), in enhanced vascular insulin sensitivity after a bout of exercise. Male Wistar rats were subjected to swimming for 2.5 h. After exercise, carbachol- or insulin-induced relaxation in aorta was assessed. Prior exercise improved insulin-stimulated vasorelaxation; however, this insulin-sensitizing effect was prevented by the selective Mas receptor (MasR; an Ang-(1-7) receptor) antagonist A779. Carbachol-mediated vascular relaxation was not modified by exercise. These results suggest that Ang-(1-7) acting through MasR participates in the enhancement of vascular insulin sensitivity after an exercise session. This new potential role of Ang-(1-7) could help in understanding how exercise improves vascular insulin sensitivity in normal and insulin-resistant states.

CARDIOMETABOLIC RISK FACTORS ASSOCIATED WITH RENAL FUNCTION IN APPARENTLY HEALTHY YOUNG STUDENTS: A CROSS-SECTIONAL STUDY.

BACKGROUND: Cardiometabolic risk factors (CMRFs) appear decades before developing chronic kidney disease (CKD) in adulthood. OBJECTIVE: The objective of the study was to identify the prevalence and association between CMRFs and kidney function in apparently healthy young adults (18-25 years old). METHODS: We included 5531 freshman year students. Data collected on CMRFs included central obesity, high body mass index (hBMI >25), blood pressure, glycemia, lipids, uric acid (UA >6.8 mg/dL), and insulin. Glomerular filtration rate (GFR) was estimated by CKD-Epidemiology Collaboration formula. We used logistic regression and a log linear for odds ratio (OR) (95% confidence level) and probabilities. RESULTS: The presence of any CMRF was observed in 78% (4312) of individuals; GFR ≥120/130 mL/min/1.73 m2sc was found in 33%, GFR <90 mL/min/1.73 m2sc in 3%, and proteinuria in 3%. Factors associated with high GFR were hBMI (OR 1.3 [1.14, 1.47]), UA (OR 0.2 [0.15, 0.26]), high-density lipoprotein (HDL) (OR 1.4 [1.2, 1.6]), and insulin resistance (OR 1.3 [1.05, 1.7]). CMRF associated with low GFR was UA (OR 1.8 [1.3, 2.6]), low-density lipoprotein cholesterol (OR 1.66 [1.05, 2.6]), and proteinuria (OR 3.4 [2.07, 5.7]). Proteinuria was associated with high UA (OR 1.59 [1.01, 2.5]) and hypercholesterolemia (OR 1.8 [1.03, 3.18]). The sole presence of hBMI+UA predicted low GFR with p = 0.6 and hBMI+UA+low HDL predicted proteinuria with p = 0.55. CONCLUSIONS: CMRFs were highly prevalent among this freshman student population and were associated with proteinuria and GFR abnormalities. Future studies should focus on public health programs to prevent or delay the development of CKD.

Functional mechanism of tracheal relaxation, antiasthmatic, and toxicological studies of 6-hydroxyflavone.

Previously, we described tracheal rat rings relaxation by several flavonoids, being 6-hydroxyflavone (6-HOF) the most active derivative of the series. Thus, its mechanism of action was determined in an ex vivo tracheal rat ring bioassay. The anti-asthmatic effect was assayed in in vivo OVAlbumin (OVA)-sensitized guinea pigs. Finally, the toxicological profile of 6-HOF was studied based on Organization of Economic Cooperation and Development guidelines with modifications. 6-HOF-induced relaxation appears to be related with receptor-operated calcium channel and voltage-operated calcium channel blockade as the main mechanism of action, and also through the production of relaxant second messengers NO and cGMP. Molecular docking supports that 6-HOF acts as calcium channel blocker and by activation of nitric oxide synthase. In addition, the in vivo anti-asthmatic experiments demonstrate the dose-dependent significant anti-allergic effect of 6-HOF induced by OVA, with best activity at 50 /kg. Finally, toxicological studies determined a LD50 > 2,000 mg/kg and, after 28 day of treatment with 6-HOF (50 mg/kg) by intragastric route, mice did not exhibit evidence of any significant toxicity. In conclusion, experiments showed that 6-HOF exerts significant relaxant activity through calcium channel blockade, and possibly, by NO/cGMP-system stimulation on rat trachea, which interferes with the contraction mechanism of smooth muscle cells in the airways. In addition, the flavonoid shows potential anti-asthmatic properties in an anti-allergic pathway. Furthermore, because the pharmacological and safety evidence, we propose this flavonoid as lead for the development of a novel therapeutic agent for the treatment of asthma and related respiratory diseases.

Ursolic acid derivatives as potential antidiabetic agents: In vitro, in vivo, and in silico studies.

Hit, Lead & Candidate Discovery Protein tyrosine phosphatase 1B (PTP-1B) has attracted interest as a novel target for the treatment of type 2 diabetes, this because its role in the insulin-signaling pathway as a negative regulator. Thus, the aim of current work was to obtain seven ursolic acid derivatives as potential antidiabetic agents with PTP-1B inhibition as main mechanism of action. Furthermore, derivatives 1-7 were submitted in vitro to enzymatic PTP-1B inhibition being 3, 5, and 7 the most active compounds (IC50  = 5.6, 4.7, and 4.6 µM, respectively). In addition, results were corroborated with in silico docking studies with PTP-1B orthosteric site A and extended binding site B, showed that 3 had polar and Van der Waals interactions in both sites with Lys120, Tyr46, Ser216, Ala217, Ile219, Asp181, Phe182, Gln262, Val49, Met258, and Gly259, showing a docking score value of -7.48 Kcal/mol, being more specific for site A. Moreover, compound 7 showed polar interaction with Gln262 and Van der Waals interactions with Ala217, Phe182, Ile219, Arg45, Tyr46, Arg47, Asp48, and Val49 with a predictive docking score of -6.43 kcal/mol, suggesting that the potential binding site could be localized in the site B adjacent to the catalytic site A. Finally, derivatives 2 and 7 (50 mg/kg) were selected to establish their in vivo antidiabetic effect using a noninsulin-dependent diabetes mice model, showing significant blood glucose lowering compared with control group (p < .05).

Prevalence of bullying by gender and education in a city with high violence and migration in Mexico.

OBJECTIVE: To understand the prevalence of bullying, by gender and educational level, in Ciudad Juárez, Mexico, a city with high rates of violence and migration. METHODS: This was a cross-sectional, observational study conducted in 2012 - 2014 using a questionnaire known as the Bullying-Mexican. A probabilistic multistage cluster-sampling method obtained a study sample of 2 347 students (10 - 27 years of age) from the 400 000 enrolled in grade 5 - university level at the 611 public schools in Ciudad Juárez. Bullying prevalence and frequency (never, rarely, sometimes, often, every day) were analyzed with descriptive statistics. The statistical differences between males and females was assessed using a chi-square test; associations between frequency and academic level were determined by correspondence analysis and the Spearman Rho correlation. A multinomial logistic regression was performed to analyze whether gender and academic level acted independently in the frequency of bullying. RESULTS: Bullying prevalence was reported by 38% of females and 47% of males: 'only victim' represented 8.7%; 'only aggressor,' 13.2%; and 'victim and aggressor,' 21%. At higher levels of education, bullying prevalence declined; however, at the university, prevalence increased in the last semesters. Mockery and social exclusion were the two most dominant types of bullying, followed by beating, threats, and punishment. CONCLUSIONS: The prevalence of bullying in Ciudad Juárez public schools is among the highest compared to other random studies and surveys. Bullying diminishes with age and educational level.

Chrysin Induces Antidiabetic, Antidyslipidemic and Anti-Inflammatory Effects in Athymic Nude Diabetic Mice.

Extensive knowledge of diabetes and its complications is helpful to find new drugs for proper treatment to stop degenerative changes derived from this disease. In this context, chrysin (5,7-dihydroxyflavone) is a natural product that occurs in a variety of flowers and fruits with anti-inflammatory and antidiabetic effects, among others. Thus, a diabetic model in athymic nude mice was developed and used to establish the ability of chrysin to decrease the secretion of pro-inflammatory cytokines. Also, it was determined the acute (50 mg/kg) and sub-acute (50 mg/kg/day/10 days) antidiabetic and antihyperlipidemic activities after the period of time treatment. Results indicate that chrysin has significant acute antihyperglycemic and antidiabetic effects in nude diabetic mice (p < 0.05). Moreover, triglyceride blood levels were reduced and IL-1ß and TNF-α were diminished after 10 days' treatment compared with control group (p < 0.05). In conclusion, it was found that chrysin could produce similar effects as metformin, a drug used for the treatment of diabetes, since both test samples decreased glucose and triglycerides levels, they impaired the generation of pro-inflammatory cytokines involved in the development of diabetes and its consequences, such as atherosclerosis and other cardiovascular diseases.

Cardiometabolic risk in young adults from northern Mexico: Revisiting body mass index and waist-circumference as predictors.

BACKGROUND: A body mass index (BMI) ≥30 kg/m(2) and a waist circumference (WC) ≥80 cm in women (WCF) or ≥90 cm in men (WCM) are reference cardiometabolic risk markers (CMM) for Mexicans adults. However, their reliability to predict other CMM (index tests) in young Mexicans has not been studied in depth. METHODS: A cross-sectional descriptive study evaluating several anthropometric, physiological and biochemical CMM from 295 young Mexicans was performed. Sensitivity (Se), specificity (Sp) and Youden's index (J) of reference BMI/WC cutoffs toward other CMM (n = 14) were obtained and their most reliable cutoffs were further calculated at Jmax. RESULTS: Prevalence, incidence and magnitude of most CMM increased along the BMI range (p < 0.01). BMI explained 81 % of WC's variance [Se (97 %), Sp (71 %), J (68 %), Jmax (86 %), BMI = 30 kg/m(2)] and 4-50 % of other CMM. The five most prevalent (≥71 %) CMM in obese subjects were high WC, low HDL-C, and three insulin-related CMM [Fasting insulin, HOMA-IR, and QUICKI]. For a BMI = 30 kg/m(2), J ranged from 16 % (HDL-C/LDL-C) to 68 % (WC), being moderately reliable (Jmax = 61-67) to predict high uric acid (UA), metabolic syndrome (MetS) and the hypertriglyceridemic-waist phenotype (HTGW). Corrected WCM/WCF were moderate-highly reliable (Jmax = 66-90) to predict HTGW, MetS, fasting glucose and UA. Most CMM were moderate-highly predicted at 27 ± 3 kg/m(2) (CI 95 %, 25-28), 85 ± 5 cm (CI 95 %, 82-88) and 81 ± 6cm (CI 95 %, 75-87), for BMI, WCM and WCF, respectively. CONCLUSION: BMI and WC are good predictors of several CMM in the studied population, although at different cutoffs than current reference values.

Early co-expression of cyclooxygenase-2 and renin in the rat kidney cortex contributes to the development of N(G)-nitro-L-arginine methyl ester induced hypertension.

We investigated the involvement of cyclooxygenase-2 (COX-2) and the renin-angiotensin system in N(G)-nitro-L-arginine methyl ester (L-NAME)-induced hypertension. Male Wistar rats were treated with L-NAME (75.0 mg·(kg body mass)(-1)·day(-1), in their drinking water) for different durations (1-33 days). COX-2 and renin mRNA were measured using real-time PCR in the renal cortex, and prostanoids were assessed in the renal perfusate, whereas angiotensin II (Ang II) and Ang (1-7) were quantified in plasma. In some rats, nitric oxide synthase inhibition was carried out in conjunction with oral administration of captopril (30.0 mg·kg(-1)·day(-1)) or celecoxib (1.0 mg·kg(-1)·day(-1)) for 2 or 19 days. We found a parallel increase in renocortical COX-2 and renin mRNA starting at day 2 of treatment with L-NAME, and both peaked at 19-25 days. In addition, L-NAME increased renal 6-Keto-PGF(1α) (prostacyclin (PGI2) metabolite) and plasma Ang II from day 2, but reduced plasma Ang (1-7) at day 19. Captopril prevented the increase in blood pressure, which was associated with lower plasma Ang II and increased COX-2-derived 6-Keto-PGF(1α) at day 2 and plasma Ang (1-7) at day 19. Celecoxib partially prevented the increase in blood pressure; this effect was associated with a reduction in plasma Ang II. These findings indicate that renal COX-2 expression increased in parallel with renin expression, renal PGI2 synthesis, and plasma Ang II in L-NAME-induced hypertension.

Parecoxib Increases Blood Pressure Through Inhibition of Cyclooxygenase-2 Messenger RNA in an Experimental Model.

BACKGROUND: Cyclooxygenase-2 selective inhibitors have been developed to alleviate pain and inflammation; however, the use of a selective cyclooxygenase-2 inhibitor is associated with mild edema, hypertension, and cardiovascular risk. AIM: To evaluate, in an experimental model in normotensive rats, the effect of treatment with parecoxib in comparison with diclofenac and aspirin and L-NAME, a non-selective nitric oxide synthetase, on mean arterial blood pressure, and cyclooxygenase-1 and -2 messenger RNA and protein expression in aortic tissue. METHODS: Rats were treated for seven days with parecoxib (10 mg/kg/day), diclofenac (3.2 mg/kg/day), aspirin (10 mg/kg/day), or L-NAME (10 mg/kg/day). Mean arterial blood pressure was evaluated in rat tail; cyclooxygenase-1 and -2 were evaluated by reverse transcription-polymerase chain reaction and Western blot analysis in aortic tissue. RESULTS: Parecoxib and L-NAME, but not aspirin and diclofenac, increased mean arterial blood pressure by about 50% (p < 0.05) without changes in cardiac frequency. Messenger RNA cyclooxygenase-1 expression in aortic tissue was not modified with any drug (p < 0.05). L-NAME and parecoxib treatment decreased messenger RNA cyclooxygenase-2 and cyclooxygenase-2 (p < 0.05). While cyclooxygenase-1 protein decreased with the three drugs tested but not with L-NAME (p < 0.05), the cyclooxygenase-2 protein decreased only with aspirin and parecoxib (p < 0.05). CONCLUSION: Parecoxib increases the blood pressure of normotensive rats by the suppression of COX-2 gene expression, which apparently induced cardiovascular control.

Plasma triglyceride/HDL-cholesterol ratio, insulin resistance, and cardiometabolic risk in young adults.

Studies in mature adults suggest that the plasma concentration ratio of triglyceride (TG)/HDL-cholesterol (HDL-C) provides a simple way to identify apparently healthy individuals who are insulin resistant (IR) and at increased cardiometabolic risk. This study extends these observations by examining the clinical utility of the TG/HDL-C ratio and the metabolic syndrome (MetS) in 2,244 healthy college students (17-24 years old) of Mexican Mestizo ancestry. The TG/HDL-C ratio separating the 25% with the highest value was used to identify IR and increased cardiometabolic risk. Cardiometabolic risk factors were more adverse in men and women whose TG/HDL-C ratios exceeded 3.5 and 2.5, respectively, and approximately one third were identified as being IR. The MetS identified fewer individuals as being IR, but their risk profile was accentuated. In conclusion, both a higher TG/HDL-C ratio and a diagnosis of the MetS identify young IR individuals with an increased cardiometabolic risk profile. The TG/HDL-C ratio identified a somewhat greater number of "high risk" subjects, whereas the MetS found a group whose risk profile was somewhat magnified. These findings suggest that the TG/HDL-C ratio may serve as a simple and clinically useful approach to identify apparently healthy, young individuals who are IR and at increased cardiometabolic risk.

Non-steroidal anti-inflammatory drugs activate NADPH oxidase in adipocytes and raise the H2O2 pool to prevent cAMP-stimulated protein kinase a activation and inhibit lipolysis.

BACKGROUND: Non-steroidal anti-inflammatory drugs (NSAIDs) -aspirin, naproxen, nimesulide, and piroxicam- lowered activation of type II cAMP-dependent protein kinase A (PKA-II) in isolated rat adipocytes, decreasing adrenaline- and dibutyryl cAMP (Bt2cAMP)-stimulated lipolysis. The molecular bases of insulin-like actions of NSAID were studied. RESULTS: Based on the reported inhibition of lipolysis by H2O2, catalase was successfully used to block NSAID inhibitory action on Bt2cAMP-stimulated lipolysis. NSAID, at (sub)micromolar range, induced an H2O2 burst in rat adipocyte plasma membranes and in whole adipocytes. NSAID-mediated rise of H2O2 was abrogated in adipocyte plasma membranes by: diphenyleneiodonium, an inhibitor of NADPH oxidase (NOX); the NOX4 antibody; and cytochrome c, trapping the NOX-formed superoxide. These three compounds prevented the inhibition of Bt2cAMP-stimulated lipolysis by NSAIDs. Inhibition of aquaporin-mediated H2O2 transport with AgNO3 in adipocytes allowed NOX activation but prevented the lipolysis inhibition promoted by NSAID: i.e., once synthesized, H2O2 must reach the lipolytic machinery. Since insulin inhibits adrenaline-stimulated lipolysis, the effect of aspirin on isoproterenol-stimulated lipolysis in rat adipocytes was studied. As expected, isoproterenol-mediated lipolysis was blunted by both insulin and aspirin. CONCLUSIONS: NSAIDs activate NOX4 in adipocytes to produce H2O2, which impairs cAMP-dependent PKA-II activation, thus preventing isoproterenol-activated lipolysis. H2O2 signaling in adipocytes is a novel and important cyclooxygenase-independent effect of NSAID.

Effect of bis-1,4-dihydropyridine in the kidney of diabetic rats.

The in vivo effectiveness of 4-dihydropyridine (bis-1,4-DHP), a new calcium-channel blocker, as a nephroprotector in isolated perfused kidney was evaluated by determining its effects on parameters associated with renal injury in diabetic rats. Diabetes in male Wistar rats, control, diabetic, control + bis-1,4-DHP, and diabetic + bis-1,4-DHP, was induced by a single administration of STZ (55 mg·kg(-1), i.p.). In the drug-treated groups, treatment with bis-1,4-DHP (10 mg·kg(-1)·day(-1)) started one week before diabetes induction; bis-1,4-DHP was dissolved in DMSO (0.3%) and suspended in drinking water with carboxymethyl cellulose (3%). Parameters evaluated were body weight, blood glucose, albuminuria, proteinuria, creatinine, urea excretion, kidney's weight / body weight ratio, and kidney perfusion pressure in all rat groups at different times of diabetes (2, 4, 6, and 10 weeks). Kidney weight of diabetic rats significantly increased vs. control, control + bis-1,4-DHP, and diabetic + bis-1,4-DHP rats at different times of diabetes. The ratios % kidney weight / 100 g body weight were different between control, control + bis-1,4-DHP, and diabetic + bis-1,4-DHP rats vs. diabetic rats (P < 0.05). Kidney perfusion pressure was decreased by diabetes, while it was partially recovered by bis-1,4-DHP treatment in response to phenylephrine. Bis-1,4-DHP had a tendency to decrease hyperglycemia vs. diabetic rats, even though glycemia was too high as compared with controls, and it ameliorated albuminuria, creatinine, and urea excretion, suggesting a favorable effect on renal haemodynamics. Bis-1,4-DHP, by inhibiting Ca(2+) entrance, induced vasodilation in renal vascular bed and thus may have a nephroprotective effect against diabetes-induced renal dysfunction, but does not have significant impact on hyperglycemia.

Ex Vivo and In Silico Approaches of Tracheal Relaxation through Calcium Channel Blockade of 6-Aminoflavone and Its Toxicological Studies in Murine Models.

Asthma is a condition in which a person's airways become inflamed, narrowed, and produce greater amounts of mucus than normal. It can cause shortness of breath, chest pain, coughing, or wheezing. In some cases, symptoms may be exacerbated. Thus, the current study was designed to determine the mechanism of action of 6-aminoflavone (6-NH2F) in ex vivo experiments, as well as to determine its toxicity in acute and sub-chronic murine models. Tissues were pre-incubated with 6-NH2F, and concentration-response curves to carbachol-induced contraction were constructed. Therefore, tracheal rings pre-treated with glibenclamide, 2-aminopyridine, or isoproterenol were contracted with carbachol (1 µM), then 6-NH2F relaxation curves were obtained. In other sets of experiments, to explore the calcium channel role in the 6-NH2F relaxant action, tissues were contracted with KCl (80 mM), and 6-NH2F was cumulatively added to induce relaxation. On the other hand, tissues were pre-incubated with the test sample, and after that, CaCl2 concentration-response curves were developed. In this context, 6-NH2F induced significant relaxation in ex vivo assays, and the effect showed a non-competitive antagonism pattern. In addition, 6-NH2F significantly relaxed the contraction induced by KCl and CaCl2, suggesting a potential calcium channel blockade, which was corroborated by in silico molecular docking that was used to approximate the mode of interaction with the L-type Ca2+ channel, where 6-NH2F showed lower affinity energy when compared with nifedipine. Finally, toxicological studies revealed that 6-NH2F possesses pharmacological safety, since it did not produce any toxic effect in both acute and sub-acute murine models. In conclusion, 6-aminoflavone exerted significant relaxation through calcium channel blockade, and the compound seems to be safe.

Δ9-Tetrahydrocannabinol Treatment Modifies Insulin Secretion in Pancreatic Islets from Prediabetic Mice Under Hypercaloric Diet.

Background: The endocannabinoid system over-activation is associated with type-2 diabetes mellitus onset, involving physiological, metabolic, and genetic alterations in pancreatic islets. The use of Δ9-Tetrahydrocannabinol (THC) as treatment is still controversial since its effects and mechanisms on insulin secretion are unclear. The aim of this study was to evaluate the effects of THC treatment in pancreatic islets from prediabetic mice. Methods: Prediabetes was induced in mice by hypercaloric diet, and then treated with THC for 3 weeks. Blood glucose and body weight were determined, after behavior tests. Histological changes were evaluated in whole pancreas; in isolated islets we analyzed the effect of THC exposure in glucose-stimulated insulin secretion (GSIS), gene expression, intracellular cyclic adenosine monophosphate (cAMP), and cytosolic calcium changes. Results: THC treatment in prediabetic mice enhanced anxiety and antidepressive behavior without changes in food ingestion, decreased oral-glucose tolerance test, plasma insulin and weight, with small alterations on pancreatic histology. In isolated islets from healthy mice THC increased GSIS, cAMP, and CB1 receptor (CB1r) expression, meanwhile calcium release was diminished. Small changes were observed in islets from prediabetic mice. Conclusions: THC treatment improves some clinical parameters in prediabetic mice, however, in isolated islets, modifies GSIS, intracellular calcium and gene expression, suggesting specific effects related to diabetes evolution.

Insulin Sensitization by PPARγ and GLUT-4 Overexpression/Translocation Mediates the Antidiabetic Effect of Plantago australis.

Plantago australis Lam. Subsp. hirtella (Kunth) Rahn is a medicinal plant used as a diuretic, anti-inflammatory, antibacterial, throat cancer treatment and for the control of diabetes. P. australis was collected in the state of Morelos, México. The hydroalcoholic extract (HAEPa) of P. australis was obtained by maceration and concentrated in vacuo. Once dry, it was evaluated through an oral glucose tolerance test (OGTT) in normoglycemic mice and in a non-insulin-dependent diabetic mice model. The expression of PPARγ and GLUT-4 mRNA was determined by rt-PCR, and GLUT-4 translocation was confirmed by confocal microscopy. The toxicological studies were conducted in accordance with the guidelines suggested by the OECD, sections 423 and 407, with some modifications. HAEPa significantly decreased glycemia in OGTT curves, as well as in the experimental diabetes model compared to the vehicle group. In vitro tests showed that HAEPa induced an α-glucosidase inhibition and increased PPARγ and GLUT-4 expression in cell culture. The LD50 of HAEPa was greater than 2000 mg/kg, and sub-chronic toxicity studies revealed that 100 mg/kg/day for 28 days did not generate toxicity. Finally, LC-MS analysis led to the identification of verbascoside, caffeic acid and geniposidic acid, and phytochemical approaches allowed for the isolation of ursolic acid, which showed significant PPARγ overexpression and augmented GLUT-4 translocation. In conclusion, HAEPa induced significant antidiabetic action by insulin sensitization through PPARγ/GLUT-4 overexpression.

LC-MS Fingerprinting Development for Standardized Precipitate from Agastache mexicana, Which Induces Antihypertensive Effect through NO Production and Calcium Channel Blockade.

The aim of this work was to evaluate the vasorelaxant and antihypertensive effects of a standardized precipitate of the hydroalcoholic extract from Agastache mexicana (PPAm), comprising ursolic acid, oleanolic acid, acacetin, luteolin and tilianin, among others. In the ex vivo experiments, preincubation with L-NAME (nonspecific inhibitor of nitric oxide synthases) reduced the relaxation induced by PPAm; nevertheless, preincubation with indomethacin (nonspecific inhibitor of cyclooxygenases) did not generate any change in the vasorelaxation, and an opposed effect was observed to the contraction generated by CaCl2 addition. Oral administration of 100 mg/kg of PPAm induced a significant acute decrease in diastolic (DBP) and systolic (SBP) blood pressure in spontaneously hypertensive rats, without changes in heart rate. Additionally, PPAm showed a sustained antihypertensive subacute effect on both DBP and SBP for 10 days compared to the control group. On the other hand, human umbilical vein cells treated with 10 µg/mL of PPAm showed a significant reduction (p < 0.05) in intracellular adhesion molecule-1, compared to the control, but not on vascular cell adhesion molecule-1. In conclusion, PPAm induces a significant antihypertensive effect in acute- and subacute-period treatments, due to its direct vasorelaxant action on rat aortic rings through NO production and Ca2+ channel blockade.

6-Amino-3-Methyl-4-(2-nitrophenyl)-1,4-Dihydropyrano[2,3-c]Pyrazole-5-Carbonitrile Shows Antihypertensive and Vasorelaxant Action via Calcium Channel Blockade.

Several 4H-pyran derivatives were designed and synthesized previously as vasorelaxant agents for potential antihypertensive drugs. In this context, the objective of the present investigation was to determine the functional mechanism of vasorelaxant action of 6-amino-3-methyl-4-(2-nitrophenyl)-1,4-dihydropyrano[2,3-c]pyrazole-5-carbonitrile (1: ) and its in vivo antihypertensive effect. Thus, compound 1: showed significant vasorelaxant action on isolated aorta rat rings pre-contracted with serotonin or noradrenaline, and the effect was not endothelium-dependent. Compound 1: induced a significant relaxant effect when aortic rings were contracted with KCl (80 mM), indicating that the main mechanism of action is related to L-type calcium channel blockade. Last was corroborated since compound 1: induced a significant concentration-dependent lowering of contraction provoked by cumulative CaCl2 adding. Moreover, compound 1: was capable to block the contraction induced by FPL 64176, a specific L-type calcium channel agonist, in a concentration-dependent manner. On the other hand, docking studies revealed that compound 1: interacts on two possible sites of the L-type calcium channel and it had better affinity energy (-7.80+/-0.00 kcal/mol on the best poses) than nifedipine (-6.86+/-0.14 kcal/mol). Finally, compound 1: (50 mg/kg) showed significant antihypertensive activity, lowering the systolic and diastolic blood pressure on spontaneously hypertensive rats (SHR) without modifying heart rate.