Preventive effects of a nutraceutical mixture of berberine, citrus and apple extracts on metabolic disturbances in Zucker fatty rats.

BACKGROUND: The prevention of obesity represents a major health and socio-economic challenge. Nutraceuticals are regularly highlighted for their beneficial effects in preventing the metabolic disturbances associated with obesity. However, few studies have described the combined action of nutraceutical mixtures combining polyphenols with alkaloids. OBJECTIVE: The aim of this study was to evaluate the effects of long-term dietary supplementation with a mixture of Berberine, Citrus and Apple extracts (BCA) in the primary prevention of obesity and its metabolic and vascular complications in the obese Zucker rat, a spontaneous model of genetic obesity and insulin resistance. METHODS: Sixteen 8-week-old obese Zucker male rats were randomly divided into two groups: all rats received oral gavage daily either with water, untreated obese (U-ObZ) or BCA (BCA-ObZ) mixture for thirteen weeks. Morphological and metabolic parameters were measured along the study. Cumulative concentration-response curves to insulin, acetylcholine and phenylephrine were determined on isolated thoracic aorta. Colon permeability measurements were performed using the Ussing chamber technique. Fecal samples collected at the beginning and the end of the protocol were used as a template for amplification of the V3-V4 region of the 16S rDNA genes. RESULTS: BCA supplementation reduced weight gain (p<0.05) and food intake (p<0.05) in the BCA-ObZ group rats compared to the U-ObZ group rats. It also improved glucose tolerance (p<0.001) and decreased fasting insulin and Homeostasis model assessment index (p<0.05). Through ex vivo experiments, the BCA mixture enhanced significantly aortic insulin relaxation (p<0.01), reduced α1-adrenoceptor-mediated vasoconstriction (p<0.01), and decreased distal colon permeability. Moreover, short-chain fatty acid producers such as Bacteroides, Blautia, and Akkermansia were found to be increased by the BCA mixture supplementation. CONCLUSION: The results showed that a 13-week-supplementation with BCA mixture prevented weight gain and improved glucose metabolism in obese Zucker rats. We also demonstrated that BCA supplementation improved vascular function, colonic barrier permeability and gut microbiota profile.

Effects of chronic mirabegron treatment on metabolic and cardiovascular parameters as well as on atherosclerotic lesions of WHHL rabbits with high-fructose high-fat diet-induced insulin resistance.

BACKGROUND AND AIM: Metabolic syndrome (MetS) is a global health and economic burden. Finding a suitable pharmacological approach for managing this syndrome is crucial. We explored the therapeutic potential of mirabegron (MIR), a ß3-adrenergic receptor agonist, as a repurposed agent for the treatment of MetS and its cardiovascular consequences. METHODS: Thirty Watanabe heritable hyperlipidemic rabbits (WHHL) were divided into 3 groups: control, high-fructose high-fat diet (HFFD) and HFFD + MIR that received a chow diet, HFFD and HFFD along with MIR treatment, respectively. The protocol lasted for 12 weeks, during which weight and abdominal circumference were monitored; plasma fasting levels of lipids, glucose and insulin were measured and an intravenous glucose tolerance test (IVGTT) was performed. Homeostasis model assessment of insulin resistance (HOMA-IR) was calculated. Cardiac function was assessed using in-vivo and ex-vivo approaches. Vascular reactivity was estimated via isolated carotid arteries method. Aortic atherosclerosis was evaluated using histological and immuno-histochemical techniques. RESULTS: In contrast to the HFFD group, MIR-treated rabbits showed fasting insulin, HOMA-IR and TG levels stabilization and exhibited improved cardiac inotropy and lusitropy, while on the other hand, displayed aggravated atheroma plaque development. CONCLUSION: Long-term treatment with MIR prevented the increase in TG levels and the establishment of IR and enhanced the cardiac function of a rabbit animal model of MetS with combined dyslipidemia and IR.

Long-term high-fructose high-fat diet feeding elicits insulin resistance, exacerbates dyslipidemia and induces gut microbiota dysbiosis in WHHL rabbits.

The metabolic syndrome (MetS) has become a global public health burden due to its link to cardiovascular disease and diabetes mellitus. The present study was designed to characterize the metabolic and cardiovascular disturbances, as well as changes in gut microbiota associated with high-fructose high-fat diet (HFFD)-induced MetS in Watanabe heritable hyperlipidemic (WHHL) rabbits. Twenty-one Watanabe rabbits were assigned to a control (n = 9) and HFFD (n = 12) groups, receiving a chow diet and a HFFD, respectively. During a 12-weeks protocol, morphological parameters were monitored; plasma fasting levels of lipids, glucose and insulin were measured and a glucose tolerance test (GTT) was performed. HOMA-IR was calculated. Cardiac function and vascular reactivity were evaluated using the Langendorff isolated heart and isolated carotid arteries methods, respectively. 16S rRNA sequencing of stool samples was used to determine gut microbial composition and abundance. HFFD-fed Watanabe rabbits exhibited increased fasting insulin (p < 0.03, 12th week vs. Baseline), HOMA-IR (p < 0.03 vs. Control), area under the curve of the GTT (p < 0.02 vs. Control), triglycerides (p < 0.05, 12th week vs. Baseline), TC (p < 0.01 vs. Control), LDL-C (p < 0.001 vs. Control). The HFFD group also displayed a significant decrease in intestinal microbial richness, evenness and diversity (FDR < 0.001, FDR < 0.0001, FDR < 0.01, respectively vs. Control group) and an increase in its Firmicutes/Bacteroidetes ratio (R = 3.39 in control vs. R = 28.24 in the HFFD group) indicating a shift in intestinal microbial composition and diversity. Our results suggest that HFFD induces insulin resistance and gut microbiota dysbiosis and accentuates dyslipidemia; and that, when subjected to HFFD, Watanabe rabbits might become a potential diet-induced MetS animal models with two main features, dyslipidemia and insulin resistance.

Soluble guanylate cyclase chronic stimulation effects on cardiovascular reactivity in cafeteria diet-induced rat model of metabolic syndrome.

Metabolic syndrome is linked to an increased risk of cardiovascular complications by a mechanism involving mainly decreased nitric oxide (NO) bioavailability and impaired NO-soluble guanylate cyclase (sGC)- cyclic guanosine monophosphate (cGMP) signalling (NO-sGC-cGMP). To further develop this scientific point, this study aimed to investigate the effects of long-term treatment with BAY 41-2272 (a sGC stimulator) on cardiovascular reactivity of spontaneously hypertensive rats (SHR) as a model of metabolic syndrome. SHR were randomly divided into 3 groups: control group, cafeteria diet (CD)-fed group and CD-fed group treated daily with BAY 41-2272 (5 mg/kg) by gastric gavage for 12 weeks. In vivo measurements of body weight, abdominal circumference, blood pressure and glucose tolerance test were performed. At the end of the feeding period, ex vivo cumulative concentration-response curves were performed on isolated perfused heart (isoproterenol (0.1 nM - 1 µM)) and thoracic aorta (phenylephrine (1 nM-10 µM), acetylcholine (1 nM-10 µM), and sodium nitroprusside (SNP) (0.1 nM-0.1 µM)). We showed that chronic CD feeding induced abdominal obesity, hypertriglyceridemia, glucose intolerance and exacerbated arterial hypertension in SHR. Compared to control group, CD-fed group showed a decrease in ß-adrenoceptor-induced cardiac inotropy, in coronary perfusion pressure and in aortic contraction to phenylephrine. While relaxing effects of acetylcholine and SNP were unchanged. BAY 41-2272 long-term treatment markedly prevented arterial hypertension development and glucose intolerance, enhanced the α1-adrenoceptor-induced vasoconstriction, and restored cardiac inotropy and coronary vasodilation. These findings suggest that BAY 41-2272 may be a potential novel drug for preventing metabolic and cardiovascular complications of metabolic syndrome.

Sildenafil citrate long-term treatment effects on cardiovascular reactivity in a SHR experimental model of metabolic syndrome.

Much evidence indicates that metabolic syndrome is strongly correlated with a decrease in nitric oxide and an increase in oxidative stress leading to cardiovascular alterations. In recent years, gut microbiota has emerged as a new contributor to the metabolic syndrome establishment and associated cardiovascular diseases, but the underlying mechanisms remain unclear. We hypothesized that a positive modulation of cyclic guanosine monophosphate (cGMP) pathway, through phosphodiesterase type 5 (PDE5) inhibition could prevent cardiovascular alterations and gut dysbiosis that may be associated to metabolic syndrome. Spontaneously hypertensive rats (SHR) were randomly divided into 4 groups: control, cafeteria diet (CD) and sildenafil citrate treated groups (5mg/kg per os) were given either a CD or a standard chow diet for 10 weeks. Body weight, arterial blood pressure and glucose tolerance test were monitored. At the 10th week, cardiac inotropy and coronary perfusion pressure were evaluated on isolated heart according to Langendorff method. Cumulative concentration response curves to phenylephrine and acetylcholine were determined on thoracic aorta rings for vascular reactivity evaluation. Faecal samples were collected for the gut microbiota analysis. Compared to the control group, CD-fed rats showed a significant increase in body weight gain, arterial blood pressure and were glucose intolerant. This group showed also a decrease in ß-adrenoceptor-induced cardiac inotropy and coronary vasodilation. Gut microbiota analysis revealed a significant reduction in the abundance of Lactobocillus spp in cafeteria diet-fed rats when compared to the control ones. Sildenafil citrate long-term treatment decreased weight gain and arterial blood pressure, improved coronary vasodilation and reduced α1-adrenoceptor-induced vasoconstriction in CD group. However, it did not reverse gut dysbiosis induced by chronic CD feeding. These results suggest that cGMP pathway targeting may be a potential therapeutic strategy for the management of the metabolic syndrome and associated cardiovascular disorders.

Long-term atorvastatin treatment decreases heart maximal oxygen consumption and its vulnerability to in vitro oxidative stress in Watanabe heritable hyperlipidemic rabbit.

Statins are currently used in prevention of cardiovascular diseases in high-risk populations, and could be considered in primary prevention. However, few studies are available on the long-term effects of low doses of statins, especially on mitochondrial function and reactive oxygen species (ROS) metabolism at cardiac level. This study aimed to determine potential effects of a long-term atorvastatin treatment, at low-dose concentration, on the myocardium mitochondrial respiration. Thirty-four Watanabe rabbits were treated or not with atorvastatin (2.5 mg·kg-1·day-1) from the age of 3 to 12 months. Every 3 months, proton leak, basal (V0), and maximal (Vmax) mitochondrial respiration on cardiac permeabilized fibers were measured. Additionally, the vulnerability to ROS, cardiac enzymatic antioxidant defenses, and oxidative damage (lipoperoxidation) were analyzed. Proton leak increased over the duration of the experiment (up to 60% from Vmax at 12 months). Moreover, the statin treatment induced a decrease of Vmax and a decrease of ROS susceptibility of cardiac mitochondria. However, the lipoperoxidation and the antioxidant defenses were not dependent on the presence of statin treatment, or on its duration. This is the first study showing a protective effect of long-term statins treatment against the ROS susceptibility in the cardiac muscle.

The relaxant effect of the Montivipera bornmuelleri snake venom on vascular contractility.

Molecular richness of snake venoms is an important source of proteins and toxins with potent effects on the cardiovascular system. The alteration of the vascular system in the victim after a venomous snake bite is usually expressed by a significant decrease in blood pressure. Therefore, exploring snake venom to extract and characterize its biomolecules is of considerable medical interest, and formed the basis of this study. We assessed the potential of the venom of Montivipera bornmuelleri, a viper from Lebanon, to induce relaxant effect on isolated Wistar rat aorta via several mechanisms of action. The overall hypotensive effect of Montivipera bornmuelleri venom results from its synergetic action on different channels for the reduction of blood pressure. By actions of its metalloproteinases and phospholipase A2, the venom may induce the production of nitric oxide acting accordingly a vasodilator effect. It could act on the voltage-dependent potassium channels and/or the L-type calcium channels, inhibiting angiotensin converting enzyme and/or inhibiting the α1-adrenoceptors. This work demonstrates vasorelaxant effect of the Montivipera bornmuelleri venom acting on different pathways, reducing blood pressure.

Effect of nebivolol treatment during pregnancy on the intrauterine fetal growth, mortality and pup postnatal development in the l-NAME-induced hypertensive rats.

The present study was carried out to evaluate the effect of nebivolol vs. bisoprolol treatment on the intrauterine fetal growth, mortality and postnatal development in Nω-Nitro-l-arginine methyl ester hydrochloride (l-NAME)-induced hypertensive rats. Hypertension was induced in normotensive pregnant Wistar rats by daily administration of l-NAME (100mg/kg/day, in the drinking water) for the period of pregnancy. After 9 days of l-NAME treatment, rats with systolic and diastolic blood pressure (SBP and DBP) more than 140/90mmHg were considered hypertensive. Then, some of them were treated from day 11 to day 18 of pregnancy with nebivolol (8mg/kg/day) or bisoprolol (10mg/kg/day) via oral gavage. SBP, DBP and heart rate (HR) were re-evaluated by tail cuff method on day 19 of pregnancy and morphometrical or histological studies were performed on day 20. In addition, the mortality and postnatal development of newborn pups were assessed in all groups. The l-NAME administration during pregnancy induced an increase in SBP and DBP while HR did not change. Nebivolol or bisoprolol treatment completely prevented the elevation of SBP and DBP induced by l-NAME with a reduction in HR in pregnant and non-pregnant rats. The intra-uterine fetal growth and the postnatal development of newborn rats in nebivolol-treated hypertensive group were significantly lower vs. control and higher vs. bisoprolol-treated group with a higher mortality in the both types of treatments vs. control rats. The nebivolol and bisoprolol administration produce adverse effects on fetal growth and postnatal development, that limits their therapeutic use in females during pregnancy.

Prospective pilot study to detect dogs with non food-induced canine atopic dermatitis using Fourier transform infrared spectroscopy.

BACKGROUND: The diagnosis of canine atopic dermatitis (CAD) remains challenging due to the lack of a simple biomarker or metabolic profile. In human medicine, Fourier transform infrared spectroscopy (FTIR) is an analytical technique used for several diseases. It requires a small amount of sample and allows the identification of structural moieties of biomolecules on the basis of their infrared absorption, with limited sample pretreatment. HYPOTHESIS/OBJECTIVES: The aim of the study was to evaluate the diagnostic value of FTIR. ANIMALS: Three groups were tested: 21 dogs with non food-induced CAD (NFICAD), 16 dogs with inflammatory conditions of various origins but without allergic dermatoses (OD) and 10 healthy dogs (H). METHODS: Peripheral blood was collected and spectra were acquired with a FTIR spectrophotometer. A principal component analysis (PCA) was performed on the full wavenumber spectra (4000-600/cm), followed by a Fisher discriminant analysis (DA) to assess the differences between the three groups. RESULTS: The PCA followed by the DA of whole spectra showed significant differences between the three groups. These results suggest that by using the FTIR method, dogs with NFICAD can be differentiated from healthy dogs and dogs with nonallergic inflammation. There was no overlap between the spectral data of the three groups indicating that NFICAD dogs were correctly segregated from the H and OD groups. CONCLUSIONS: A study on a larger cohort including common pruritic skin diseases is necessary to confirm these initial results and the relevance of this diagnostic technique.

A non-hypocholesterolemic atorvastatin treatment improves vessel elasticity by acting on elastin composition in WHHL rabbits.

BACKGROUND AND AIMS: Statins are prescribed for their preventative effects within atherosclerosis development. To our knowledge, no study focusing on very low-dose (non-hypolipidemic effect) and long-term atorvastatin treatment in vivo was available. Our aim was to assess the effect of such atorvastatin treatment on the mechanical and functional characteristics of arteries in the context of primary prevention. METHODS: An atorvastatin treatment (2.5 mg/kg/day) was tested against controls on 34 male 3 to 12 month-old WHHL rabbits. No effect on total cholesterol, triglycerides, HDL or LDL was observed. The arterial stiffness was evaluated on vigil animals by pulse wave velocity (PWV) measurement. Then, in vitro measurements were made to evaluate (1) the endothelial and vascular smooth muscle function, (2) the elasticity of the arterial wall and (3) the composition in collagen and elastin in the aorta. RESULTS: The PWV increasing observed with age in control group was canceled by treatment, creating a significance difference between groups at 12 months (5.17 ± 0.50 vs 2.14 ± 0.34 m s(-1) in control and treated groups respectively). Vasoreactivity modifications can't explain this result but maintain of elasticity with treatment in large arteries was confirm by a static tensile test. A first possible explanation is the change of wall composition with treatment, validated by the percentage of elastin at 12 months, 4.4% lower in the control group compared to the treated group (p < 0.05). CONCLUSIONS: This study shows that a non-hypocholesterolemic statin treatment could improve vessel elasticity in the atherosclerotic WHHL model. The great novelty of this work is the vessel wall composition changing associated. This first approach in animal opens the reflection on the use of these low doses in humans. This could be interesting in the context of arterial stiffening with aging, non-hyperlipidemic atherosclerosis or with cholesterol reduce by another therapy or lifestyle modification.