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•Cinnamon reduced serum concentration of total T3 in hypothyroid rats.•Cinnamon supplementation did not reverse the hypercholesterolemia in hypothyroid rats.•Cinnamon induced hepatic ...accumulation of triglyceride and free fatty acids.•Thyroid state is a decisive factor for the beneficial effects of cinnamon.
Hypolipidemic effects of cinnamon (Cinnamomum zeylanicum) have been described in humans and in experimental animals. Hypothyroidism is frequently associated with hyperlipidemia. Here we investigated the effects of chronic ingestion of cinnamon on lipid metabolism of hypothyroid male Wistar rats. Rats received methimazole for 7 weeks, and treated either with cinnamon as powder added to the chow or aqueous extract of cinnamon, during the last 4 weeks of protocol, and compared to untreated hypothyroid and euthyroid rats. Cinnamon intake reduced body mass increasing fat mass and reducing body protein content of hypothyroid rats. Cinnamon ingestion did not revert the hypercholesterolemia of hypothyroid rats and promoted a further reduction in serum T3, suggesting a worsening of the hypothyroid condition. Our results indicate that the beneficial effects of cinnamon on lipid metabolism are impaired in hypothyroidism.
In models of metabolic disorders, cinnamon improves glucose and lipid metabolism. This study explores the effect of chronic supplementation with aqueous cinnamon extract (CE) on the lipid metabolism ...of rats. Male adult Wistar rats were separated into a control group (CTR) receiving water and a CE Group receiving aqueous cinnamon extract (400 mg of cinnamon per kg body mass per day) by gavage for 25 consecutive days. Cinnamon supplementation did not change the food intake or the serum lipid profile but promoted the following changes: lower body mass gain (P = 0.008), lower relative mass of white adipose tissue (WAT) compartments (P = 0.045) and higher protein content (percentage of the carcass) (P = 0.049). The CE group showed lower leptin mRNA expression in the WAT (P = 0.0017) and an important tendency for reduced serum leptin levels (P = 0.059). Cinnamon supplementation induced lower mRNA expression of SREBP1c (sterol regulatory element-binding protein 1c) in the WAT (P = 0.001) and liver (P = 0.013) and lower mRNA expression of SREBP2 (P = 0.002), HMGCoA reductase (3-hydroxy-3-methylglutaryl-CoA reductase) (P = 0.0003), ACAT1 (acetyl-CoA acetyltransferase 1) (P = 0.032) and DGAT2 (diacylglycerol O-acyltransferase 2) (P = 0.03) in the liver. These changes could be associated with the reduced esterified cholesterol and triacylglycerol content detected in this tissue. Our results suggest that chronic ingestion of aqueous cinnamon extract attenuates lipogenic processes, regulating the expression of key enzymes and transcriptional factors and their target genes, which are directly involved in lipogenesis. These molecular changes possibly promote adaptations that would prevent an increase in circulating cholesterol and triacylglycerol levels and prevent lipid accumulation in tissues, such as liver and WAT. Therefore, we speculate that cinnamon may also be useful for preventing or retarding the development of lipid disorders.
Leptin has been shown to regulate the hypothalamus-pituitary-thyroid axis, acting primarily through the STAT3 pathway triggered through the binding of leptin to the long-chain isoform of the leptin ...receptor, ObRb. We previously demonstrated that although hyperthyroid rats presented leptin effects on TSH secretion, those effects were abolished in hypothyroid rats. We addressed the hypothesis that changes in the STAT3 pathway might explain the lack of TSH response to leptin in hypothyroidism by evaluating the protein content of components of leptin signalling via the STAT3 pathway in the hypothalamus and pituitary of hypothyroid (0·03% methimazole in the drinking water/21 days) and hyperthyroid (thyroxine 5 μg/100 g body weight /5 days) rats. Hypothyroid rats exhibited decreased ObRb and phosphorylated STAT3 (pSTAT3) protein in the hypothalamus, and in the pituitary gland they exhibited decreased ObRb, total STAT3, pSTAT3 and SOCS3 (P<0·05). Except for a modest decrease in pituitary STAT3, no other alterations were observed in hyperthyroid rats. Moreover, unlike euthyroid rats, the hypothyroid rats did not exhibit a reduction in food ingestion after a single injection of leptin (0·5 mg/kg body weight). Therefore, hypothyroidism decreased ObRb-STAT3 signalling in the hypothalamus and pituitary gland, which likely contributes to the loss of leptin action on food intake and TSH secretion, as previously observed in hypothyroid rats.
α-Class GST (Gsta) represents an essential component of cellular antioxidant defense mechanisms in both the liver and the kidney. Estrogens and thyroid hormones (TH) play central roles in animal ...development, physiology, and behavior. Evidence of the overlapping functions of thyroid hormones and estrogens has been shown, although the molecular mechanisms are not always clear. We evaluated an interaction between TH and estradiol in regulating kidney Gsta expression and function. First, we observed that female mice expressed greater amounts of Gsta compared with males and showed an opposite pattern of expression in TRβ knock-in mice. To further investigate these sex differences, hypothyroidism was induced by a 5-propyl-2-thiouracil diet, and hyperthyroidism was induced by daily T₃ injections. Hypothyroidism increased kidney Gsta expression in male mice but not in female mice, indicating that sex hormones could be influencing the regulation of Gsta by thyroid hormones. To analyze this hypothesis, ovariectomized females were subjected to hypo- and hyperthyroidism, which led to a male profile of Gsta expression. When hypo- or hyperthyroid ovariectomized mice were treated with 17β-estradiol benzoate, we were able to confirm that estradiol was interfering with TH modulation; Gsta expression is increased by T₃ when estradiol is present and decreased by T₃ when estradiol is absent. Using proximal tubule cells, we also showed that estradiol and T₃ worked together to modulate Gsta expression in an overlapping fashion. In summary, 1) the sex difference in the basal expression of Gsta impacts the detoxification process, 2) kidney Gsta expression is regulated by TH in males and females but in opposite directions, and 3) T₃ and estradiol interact directly in renal proximal cells to regulate Gsta expression in females.
The effect of pH and crossflow velocity on the ultrafiltration of a model metalworking o/w emulsion was studied. The emulsion was prepared using a vegetable oil as the base oil and a mixture of ...anionic and non-ionic surfactants as emulsifiers. Experiments were carried out using Carbosep
® tubular ceramic membranes with two different cut offs (50 and 300
kDa) in a transmembrane pressure range of 0.05–0.4
MPa. Concentration polarization was observed at low crossflow velocities. Zeta potential and droplet size distribution measurements showed that properties of the o/w emulsion are not affected by pH. However, both permeate flux and chemical oxygen demand (COD) retention decreased drastically at low pH values, since membranes become positively charged and adsorption of anionic surfactants onto the membrane surface takes place, making it more hydrophobic and causing flux decline and surfactant monomers permeation through the membrane. The resistance-in-series (RIS) model was applied in order to ascertain the main resistances to the permeate flux. COD retentions higher than 92% were achieved for all the operating conditions with both membranes.
•HIPEs with controlled droplet size were prepared by a two-step process.•Vacuum evaporation allowed to obtain HIPEs with no variation of mean droplet size.•HIPEs are suitable systems for lutein ...encapsulation showing efficiencies up to 97%.•HIPEs show high creaming resistance and retard lutein delivery.
A two-step technique for preparing highly concentrated oil-in-water (O/W) emulsions, also called high internal phase emulsions (HIPEs) is proposed. Four different oils were selected as the internal phase: castor oil, heavy mineral oil, soybean oil and light mineral oil, and a non-ionic surfactant Tween 20 (polyoxyethylenesorbitan monolaurate) was chosen as stabilizer. Deionized water with 1% (w/v) NaCl was the external phase. First, a dilute O/W emulsion was prepared either by mechanical agitation or membrane emulsification and then concentrated by evaporation at high vacuum and temperatures not exceeding 40°C to avoid emulsion phase inversion. Oil droplet size distribution and viscosity were measured to assess the vacuum evaporation performance. Visual inspection of the emulsion using soluble dyes and conductivity measurements showed the nature and characteristics of the final emulsion. Creaming stability of the formulated emulsions was also studied. O/W emulsions with an internal phase concentration up to 90% (v/v) could be prepared by mechanical agitation and evaporation. Emulsions obtained by membrane emulsification showed high monodispersity and could be concentrated up to 75% (v/v) of internal phase. High internal phase emulsions were used as lutein carriers. An appropriate selection of oily internal phase and the addition of sodium carboxymethylcellulose (CMCNa) as stabilizer in the external phase increased lutein encapsulation efficiency (EE) up to 97%.
The aim of this work was to prepare size-tuned nanovesicles using a modified ethanol injection method (EIM) by applying factorial experimental design. Stable size-tuned nanovesicles (liposomes and ...niosomes) with controlled sizes and high EE values for hydrophobic compounds (Sudan Red 7B and vitamin D3) were achieved. Equations that were able to predict the mean particle sizes, in the ranges of 55–156 nm for liposomes and 224–362 nm for niosomes with PDI values between 0.032 and 0.378, were obtained. These customized soft nanoparticles could be suitable in food, cosmetic, pharmaceutical, or medical applications, such as diagnosis or therapy.
Previous studies have proposed a role for neuromedin B (NB), a bombesin‐like peptide, in the control of body weight homeostasis. However, the nature of this role is unclear. The actions of NB are ...mediated preferentially by NB‐preferring receptors (NBRs). Here we examined the consequences of targeted deletion of NBRs in female mice on body weight homeostasis in mice fed a normolipid diet (ND) or a high‐fat diet (HFD) for 13 weeks. Body weight and food ingestion of neuromedin B receptor knockout (NBR‐KO) mice fed a normolipid diet showed no difference in relation to wild‐type (WT). However, the high‐fat diet induced an 8.9‐ and 4.8‐fold increase in body weight of WT and NBR‐KO, respectively, compared to their controls maintained with a normolipid diet, even though the mice ingested the same amount of calories, regardless of genotype. Comparing mice fed the high‐fat diet, NBR‐KO mice accumulated approximately 45% less fat depot mass than WT, exhibited a lower percentage of fat in their carcasses (19.2 vs. 31.3%), and their adipocytes were less hypertrophied. Serum leptin and leptin mRNA in inguinal and perigonadal fat were lower in HFD NBR‐KO than HFD WT, and serum adiponectin was similar among HFD groups and unaltered in comparison to ND‐fed mice. HFD‐fed WT mice developed glucose intolerance but not the HFD‐fed NBR‐KO mice, although they had similar glycaemia and insulinaemia. NBR‐KO and WT mice on the normolipid diet showed no differences in any parameters, except for a trend to lower insulin levels. Therefore, disruption of the neuromedin B receptor pathway did not change body weight homeostasis in female mice fed a normolipid diet; however, it did result in partial resistance to diet‐induced obesity.
The peptide neuromedin B, found in the central nervous system, gastrointestinal tract and adipose tissue of mammals, has been implicated in the control of food ingestion and energy homeostasis; however, its physiological role in these processes is unknown. We showed that female mice with disruption of neuromedin B receptors have normal body weight and food intake when fed a normal balanced diet, but they were partially resistant to obesity induced by a high‐fat diet. This was not due to changes in food intake which was similar between genotypes. The data suggest the involvement of the neuromedin B receptor pathway in the control of energy metabolism leading to protection against the development of obesity. Further studies are being conducted to investigate the involved mechanisms.
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