In vivo and in silico study of antioxidant and anti-inflammatory effects on the liver-spleen axis of microencapsulated brewers' spent grain peptides.

Metabolic syndrome (MS) is a cluster of risk factors for the development of cardiovascular disease and type 2 diabetes mellitus. Some dietary bioactive compounds such as peptides can exert dual antioxidant and anti-inflammatory effects. The aim of this study was to analyze the effects of microencapsulated brewers' spent grain peptides (BSG-P-MC) on hepatic injury, lipid peroxidation, oxidative stress and inflammation in the liver-spleen axis in Wistar rats fed with a sucrose-rich diet (SRD). Male rats received for 100 days a reference diet (RD), SRD or RD and SRD containing 700 mg per kg body weight per day of BSG-P-MC. The results demonstrated that BSG-P-MC reversed injury, lipid peroxidation, and oxidative stress in the liver. For the spleen, BSG-P-MC decreased the levels of lipid peroxidation, CAT activity, NFκB, PAI-1 and F4/80 protein mass levels with respect to the SRD-fed rats. Three peptides identified by LC-MS/MS from BSG-P-MC after in vitro gastrointestinal digestion showed high in silico free radical scavenging activity (LPRDPYVDPMAPLPR, ANLPRDPYVDPMAPLPRSGPE and ANLPRDPYVDPMAPLPR). Moreover, two identified peptides presented high in silico anti-inflammatory properties (LTIGDTVPNLELDSTHGKIR and VDPDEKDAQGQLPSRT). This study is the first report of antioxidant and anti-inflammatory properties of microencapsulated BSG-peptides exerted in the liver-spleen axis in a MS rodent model.

EFECTOS DE DIFERENTES FUENTES DE ÁCIDOS GRASOS N-3 (CHÍA, VEGETAL Y MARINA, ANIMAL) SOBRE COMPONENTES DEL SÍNDROME METABÓLICO EN MODELOS EXPERIMENTALES (RATAS/RATONES) / EFFECTS OF DIFFERENT SOURCES OF N-3 FATTY ACIDS (CHIA, VEGETAL AND MARINE, ANIMAL) ON METABOLIC SYNDROME COMPONENTS IN EXPERIMENTAL MODELS (RATS/MOUSES)

El síndrome metabólico (SM) constituye una constelación de factores interrelacionados que elevan el riesgo de padecer enfermedad cardiovascular y diabetes mellitus tipo 2. La composición de la dieta es crucial en la modificación de estos factores. Numerosos trabajos focalizaron su atención en fuentes de ácidos grasos n-3 de origen marino (animal) en el manejo de estos trastornos, pero más escasos y contemporáneos son aquellos de fuentes n-3 de origen vegetal.

Dietary soy protein improves adipose tissue dysfunction by modulating parameters related with oxidative stress in dyslipidemic insulin-resistant rats.

The present study investigates the benefits of the dietary intake of soy protein on adipose tissue dysfunction in a rat model that mimics several aspects of the human metabolic syndrome. Wistar rats were fed a sucrose-rich diet (SRD) for 4 months. After that, half of the animals continued with SRD until month 8 while in the other half, casein protein was replaced by isolated soy protein for 4 months (SRD-S). A reference group consumed a control diet all the time. In adipose tissue we determined: i) the activities of antioxidant enzymes, gene expression of Mn-superoxide dismutase (SOD) and glutathione peroxidase (GPx), and glutathione redox state ii) the activity of xanthine oxidase (XO), ROS levels and the gene expression of NAD(P)H oxidase iii) the expression of the nuclear factor erythroid-2 related factor-2 (Nrf2). Besides, adiposity visceral index, insulin sensitivity, and tumor necrosis factor-α (TNF-α) in plasma were determined. Compared with the SRD-fed rats, the animals fed a SRD-S showed: activity normalization of SOD and glutathione reductase, improvement of mRNA SOD and normalization of mRNA GPx without changes in the expression of the Nrf2, and improvement of glutathione redox state. These results were accompanied by a normalization of XO activity and improvement of both the ROS production as well as TNF-α levels in plasma. Besides, adipocyte size distribution, adiposity visceral index and insulin sensitivity improved. The results suggest that soy protein can be a complementary nutrient for treating some signs of the metabolic syndrome.

Fish oil reverses the altered glucose transporter, phosphorylation, insulin receptor substrate-1 protein level and lipid contents in the skeletal muscle of sucrose-rich diet fed rats.

The role and underlying mechanisms by which n-3 polyunsaturated fatty acids (PUFA) prevent/reverse SRD-induced insulin resistance (IR) in the muscle are not completely understood. Therefore, we examined: triglyceride, diacylglycerol, PKCθ, Glut-4, enzymatic hexokinase activity, IRS-1 protein mass level, and fatty acid composition of muscle phospholipids. Rats were fed a SRD during 6 months. Thereafter, half the animals continued with SRD up to 8 months; the other half was fed a SRD in which CO (8% wt/wt) was replaced by FO (7%+1% CO) for 2 months. Results were compared with those obtained in rats fed a control diet (CD). In SRD-fed rats, FO oil normalized/improved lipid storage and PKCθ protein mass level. Effects of insulin were comparable with those of CD-fed rats. FO reversed impaired glucose phosphorylation, IRS-1, and, under insulin stimulation, Glut-4 protein mass level. FO normalized insulin resistance and increased n-3 PUFAs in muscle phospholipids.

Sucrose-rich feeding during rat pregnancy-lactation and/or after weaning alters glucose and lipid metabolism in adult offspring.

1. Adverse fetal and early life environments predispose to the development of metabolic disorders in adulthood. The present study examined whether offspring of normal Wistar dams fed a high-sucrose diet (SRD) developed impaired lipid and glucose homeostasis when fed a control diet (CD) after weaning. In addition, we investigated whether there were more pronounced derangements in lipid and glucose homeostasis when offspring of SRD-fed Wistar were fed an SRD after weaning compared with those in offspring of CD-fed dams weaned on an SRD. 2. During pregnancy and lactation, female rats were fed either an SRD or CD. After weaning, half the male offspring from both groups were fed a CD or SRD, up to 100 days of age (CD-CD, CD-SRD, SRD-SRD and SRD-CD groups). 3. Final bodyweight was similar between all groups, although offspring of SRD-fed dams had lighter bodyweight at birth. Plasma lipid and glucose levels were significantly higher (P < 0.05) without changes in insulin levels in the CD-SRD, SRD-SRD and SRD-CD groups compared with the CD-CD group. Dyslipidaemia in the CD-SRD and SRD-SRD groups resulted from increased secretion of very low-density lipoprotein triacylglycerol, as well as decreased triacylglycerol (TAG) clearance that was associated with increased liver TAG content (P < 0.05) compared with the CD-CD group. The hypertriglyceridaemia observed in the SRD-CD group was mostly associated with decreased TAG clearance. Altered glucose and insulin tolerance were observed when the SRD was fed during any period of life. 4. These data support the hypothesis that early life exposure to SRD is associated with changes in lipid and glucose metabolism, leading to an unfavourable profile in adulthood, regardless of whether offspring consumed an SRD after weaning.

Soya protein ameliorates the metabolic abnormalities of dysfunctional adipose tissue of dyslipidaemic rats fed a sucrose-rich diet.

The present study investigates whether the replacement of dietary casein by soya protein isolate could be able to improve and/or even revert the morphological and metabolic abnormalities underlying the adipose tissue dysfunction of dyslipidaemic rats chronically fed (8 months) a sucrose-rich (62·5 %) diet (SRD). For this purpose, Wistar rats were fed a SRD for 4 months. From months 4 to 8, half the animals continued with the SRD and the other half were fed a SRD in which the source of protein, casein, was substituted by soya. The control group received a diet in which the source of carbohydrate was maize starch. Compared with the SRD-fed group, the results showed that: (1) soya protein decreased body-weight gain, limited the accretion of visceral adiposity and decreased adipose tissue cell volume without changes in total cell number; (2) soya protein increased the protein mass expression of PPARγ, which was significantly reduced in the fat pad of the SRD-fed rats; (3) the activity of the enzymes involved in the de novo lipogenesis of adipose tissue was significantly decreased/normalised; (4) soya protein corrected the inhibitory effect of SRD upon the anti-lipolytic action of insulin, reduced basal lipolysis and normalised the protein mass expression of GLUT-4. Dyslipidaemia, glucose homeostasis and plasma leptin levels returned to control values. The present study provides data showing the beneficial effects of soya protein to improve and/or revert the adipose tissue dysfunction of a dyslipidaemic insulin-resistant rat model and suggests that soya could maintain the functionality of the adipose tissue-liver axis improving/reverting lipotoxicity.

Dietary chia seed (Salvia hispanica L.) rich in alpha-linolenic acid improves adiposity and normalises hypertriacylglycerolaemia and insulin resistance in dyslipaemic rats.

The present study investigates the benefits of the dietary intake of chia seed (Salvia hispanica L.) rich in alpha-linolenic acid and fibre upon dyslipidaemia and insulin resistance (IR), induced by intake of a sucrose-rich (62.5 %) diet (SRD). To achieve these goals two sets of experiments were designed: (i) to study the prevention of onset of dyslipidaemia and IR in Wistar rats fed during 3 weeks with a SRD in which chia seed was the dietary source of fat; (ii) to analyse the effectiveness of chia seed in improving or reversing the metabolic abnormalities described above. Rats were fed a SRD during 3 months; by the end of this period, stable dyslipidaemia and IR were present in the animals. From months 3-5, half the animals continued with the SRD and the other half were fed a SRD in which the source of fat was substituted by chia seed (SRD+chia). The control group received a diet in which sucrose was replaced by maize starch. The results showed that: (i) dietary chia seed prevented the onset of dyslipidaemia and IR in the rats fed the SRD for 3 weeks--glycaemia did not change; (ii) dyslipidaemia and IR in the long-term SRD-fed rats were normalised without changes in insulinaemia when chia seed provided the dietary fat during the last 2 months of the feeding period. Dietary chia seed reduced the visceral adiposity present in the SRD rats. The present study provides new data regarding the beneficial effect of chia seed upon lipid and glucose homeostasis in an experimental model of dislipidaemia and IR.

Efectos de sustratos competitivos y de la insulina sobre la captación y el destino metabólico de la glucosa en corazón perfundido de ratas dislipémicas / Effects of competitive substrates ans insulin on glucose uptake and utilization in isolated perfused hearts of dyslipemic rats

Rats chronically fed (15 weeks) a sucrose-rich diet (SRD) developed hypertriglyceridemia (hyperTg), increased plasma free fatty acids (FFA), impaired glucose homeostasis and insulin insensitivity. An increase of Tg and glycogen (Gly) in heart muscle was also observed. HyperTg with altered glucose metabolism could have profound effects on myocardial glucose utilization. To test this hypothesis male Wistar rats were fed a semi-synthetic SRD (w/w: 62.5% sucrose, 8% corn-oil, 17% protein), and the control group (CD) received the same semi-synthetic diet, except that sucrose was replaced with starch for 90 days. At that time, the hearts from these animals were isolated and perfused for 30 min in the presence or absence of insulin (30 mU/ml). Levels of the exogenous substrates were similar to those found in the plasma of the animal in vivo in both dietary groups (glucose 8.5 mM, palmitate 0.8 mM in SRD and glucose 5-5 mM, palmitate 0.3 mM in CD). In the absence of insulin glucose uptake was reduced (40%) and lactate release was increased (50%) in SRD hearts. Glucose oxidation was depressed mainly due to both, an increase of PDH kinase and a decrease of 60% of PDHa (active form of PDHc). Insulin in the perfusion medium improved only glucose uptake. The results suggest that at least two different mechanisms might contribute to insulin resistance and to impaired glucose metabolism in the perfused hearts of dyslipemic SRD fed rats: 1) reduced basal and insulin-stimulated glucose uptake and its utilization and 2) increased availability and oxidation of lipids (low PDHa and PDH kinase activities), which in turn decreased glucose uptake and utilization. Thus, this experimental model may be useful to study how impaired glucose homeostasis, increased plasma FFA and hyperTg could contribute to heart tissue malfunction.