Effect of Brassica rapa var. rapifera on Insulin Resistance and Inflammatory Analysis of Visceral Adipose Tissue of Obese Wistar Rats Under Glucolipotoxicity Condition / Efecto de Brassica rapa var. rapifera sobre la Resistencia a la Insulina y el Análisis Inflamatorio del Tejido Adiposo Visceral de Ratas Wistar Obesas en Condiciones de Glucolipotoxicidad

SUMMARY: Obesity-related pathophysiologies such as insulin resistance and the metabolic syndrome show a markedly increased risk for type 2 diabetes and atherosclerotic cardiovascular disease. This risk appears to be linked to alterations in adipose tissue function, leading to chronic inflammation and the dysregulation of adipocyte-derived factors. Brassica rapa have been used in traditional medicine for the treatment of several diseases, including diabetes. This study aimed to investigate the effect of nutritional stress induced by a high-fat and high-sucrose diet on the pathophysiology of visceral adipose tissue and the therapeutic effect of Brassica rapa in male Wistar rats. We subjected experimental rats to a high-fat (10 %) high-sucrose (20 %)/per day for 11 months and treated them for 20 days with aqueous extract Br (AEBr) at 200 mg/kg at the end of the experiment. At the time of sacrifice, we monitored plasma and tissue biochemical parameters as well as the morpho-histopathology of visceral adipose tissue. We found AEBr corrected metabolic parameters and inflammatory markers in homogenized visceral adipose tissue and reduced hypertrophy, hyperplasia, and lipid droplets. These results suggest that AEBr enhances anti-diabetic, anti-inflammatory and a protective effect on adipose tissue morphology in type 2 diabetes and obesity.

La fisiopatología relacionadas con la obesidad, como la resistencia a la insulina y el síndrome metabólico, muestran un riesgo notablemente mayor de diabetes tipo 2 y enfermedad cardiovascular aterosclerótica. Este riesgo parece estar relacionado con alteraciones en la función del tejido adiposo, lo que lleva a una inflamación crónica y a la desregulación de los factores derivados de los adipocitos. Brassica rapa se ha utilizado en la medicina tradicional para el tratamiento de varias enfermedades, incluida la diabetes. Este estudio tuvo como objetivo investigar el efecto del estrés nutricional inducido por una dieta rica en grasas y sacarosa sobre la fisiopatología del tejido adiposo visceral y el efecto terapéutico de Brassica rapa en ratas Wistar macho. Sometimos a ratas experimentales a una dieta rica en grasas (10 %) y alta en sacarosa (20 %)/por día durante 11 meses y las tratamos durante 20 días con extracto acuoso de Br (AEBr) a 200 mg/kg al final del experimento. En el momento del sacrificio, monitoreamos los parámetros bioquímicos plasmáticos y tisulares, así como la morfohistopatología del tejido adiposo visceral. Encontramos parámetros metabólicos corregidos por AEBr y marcadores inflamatorios en tejido adiposo visceral homogeneizado y reducción de hipertrofia, hiperplasia y gotitas de lípidos. Estos resultados sugieren que AEBr mejora el efecto antidiabético, antiinflamatorio y protector sobre la morfología del tejido adiposo en la diabetes tipo 2 y la obesidad.

Hypothyroidism increases angiotensinogen gene expression associated with vascular smooth muscle cells cholesterol metabolism dysfunction and aorta remodeling in Psammomys obesus.

It has been previously shown that clinical cardiovascular manifestations can be caused by mild changes in thyroid function. However, the implication of angiotensinogen (Agt) and vascular smooth muscle cells (VSMCs) dysfunction in the pathophysiology of cardiovascular manifestations in hypothyroidism have not yet been investigated. We induced experimental hypothyroidism in Psammomys obesus by administering carbimazole for five months. At the end of the experiment, the animals were sacrificed and histopathological analysis was performed using Masson's trichrome staining of the aorta and thyroid gland. The expression of the Agt gene and the genes implicated in cholesterol metabolism regulation in the liver and VSMCs was determined by qRT-PCR. Histological observations revealed profound remodeling of the aorta structure in animals with hypothyroidism. In addition, Agt gene expression in the liver was significantly increased. In vitro study, showed that VSMCs from hypothyroid animals overexpressed 3-hydroxy-3-methylglutaryl coenzyme A reductase (Hmgcr) and Acyl CoA:cholesterol acyltransferase (Acat) 1, with failure to increase the efflux pathway genes (ATP-binding cassette subfamily G member (Abcg) 1 and 4). These results suggest that hypothyroidism leads to vascular alterations, including structural remodeling, VSMCs cholesterol metabolism dysfunction, and their switch to a synthetic phenotype, together with hepatic Agt gene overexpression.

Scolymus hispanicus (Golden Thistle) Ameliorates Hepatic Steatosis and Metabolic Syndrome by Reducing Lipid Accumulation, Oxidative Stress, and Inflammation in Rats under Hyperfatty Diet.

BACKGROUND: Lipotoxicity is characterized by a metabolic disturbance leading to the development of nonalcoholic fatty liver disease (NAFLD). Some medicinal plant extracts exert hepatoprotective activity by modulating oxidative stress, inflammation, and metabolic disorders. Scolymus hispanicus or the golden thistle can be considered an important natural source of antioxidants. In traditional medicine, the consumption of this plant is recommended for diseases of the liver and intestines. OBJECTIVE: In this study, we aimed to determine the effects of Scolymus hispanicus on a hyperfatty diet- (HFD-) induced metabolic disorders, oxidative stress, and inflammation. MATERIALS AND METHODS: Our experiment focused on the administration of an HFD (40%) in Rattus norvegicus for 2 months and treatment with the aqueous extract of Scolymus hispanicus at a rate of 100 mg/kg during the last eight days of experimentation. In this context, several aspects were studied: the evaluation of blood biochemical parameters, liver function such as lipids and glycogen, markers of oxidative stress (TBARS, carbonyl proteins, advanced oxidation proteins, catalase, and SOD) and inflammation (NO and NFkB), morphological study of hepatocytes in primary culture, and histological study of the liver. RESULTS: Lipotoxicity induced metabolic disorders, both serum and tissue. HFD induced an increase in the total lipids and a decrease in glycogen reserve and an alteration in the oxidant-antioxidant balance. HFD induced an increase in markers of liver damage, which resulted in NAFLD, confirmed by histological study and hepatocytes cell culture. Scolymus appears to have lipid-lowering, hypoglycemic, anti-inflammatory and antioxidant properties. It improved glucose tolerance and the condition of fatty liver disease. CONCLUSION: Golden thistle improves glucose tolerance and hyperlipidemia and ameliorates hepatic steatosis by reducing oxidative stress, inflammation, and lipid accumulation. Its incorporation into a dietary program or as an aliment supplement would prevent hepatic complications associated with an HFD.

TRα inhibits arterial renin-angiotensin system expression and prevents cholesterol accumulation in vascular smooth muscle cells.

OBJECTIVES: The tissue renin-angiotensin system (tRAS) plays a key role in the maintenance of cellular homeostasis but is also implicated in atherosclerosis. Thyroid hormone (TH) contributes, via genomic effects, to control of tRAS gene expression in the arterial wall and vascular smooth muscle cells (VSMCs). We investigated the specific functions of TH receptors-α and -ß (TRα and TRß) on tRAS gene expression in the aorta and VSMCs, and the potential protective effect of TRα against atherosclerosis. MATERIAL AND METHODS: Using aorta and cultured aortic VSMCs from TRα and TRß deficient mice, tRAS gene expression was analyzed by determining mRNA levels on real-time PCR. Gene regulation under cholesterol loading mimicking atherosclerosis conditions was also examined in VSMCs in vitro. RESULTS: TRα deletion significantly increased expression of angiotensinogen (AGT) and angiotensin II receptor type 1 subtype a (AT1Ra) at transcriptional level in aorta, a tissue with high TRα expression level. TRα activity thus seems to be required for maintenance of physiological levels of AGTand AT1Raexpression in the arterial wall. In addition, during cholesterol loading, TRα deletion significantly increased cholesterol content in VSMCs, with a weaker decrease in AGTexpression. CONCLUSION: TRα seems to have an inhibitory impact on AGTand AT1Raexpression, and loss of TRα function in TRα0/0 mice increases tRAS expression in the aortic wall. More importantly, TRα deletion significantly increases VSMC cholesterol content. Our results are consistent with a protective role of TRα against atherosclerosis.

Thyroid Hormone Receptor Alpha Deletion in ApoE-/- Mice Alters the Arterial Renin-Angiotensin System and Vascular Smooth Muscular Cell Cholesterol Metabolism.

Thyroid hormone (TH) regulates gene transcription by binding to TH receptors (TRs). TRs regulate the genes of lipid metabolism and the renin-angiotensin system (RAS). We examined the effect of TRα deletion in ApoE-/- mice (DKO mice) on the following: (i) the expression of genes controlling cholesterol metabolism and tissue (t)RAS in the liver and aorta and (ii) the expression of these genes and the regulation of cholesterol content in cultured vascular smooth muscle cells (VSMCs). TRα deletion in ApoE-/- mice led to the repression of genes involved in the synthesis and influx of cholesterol in the liver. However, TRα deletion in the arterial wall suppressed the expression of genes involved in the esterification and excretion of cholesterol and enhanced the expression of angiotensinogen (AGT). The VSMCs of the ApoE-/- and DKO mice increased their cholesterol content during cholesterol loading, but failed to increase the expression of ATP-binding cassette transporter A1 (ABCA1). T3 addition partially corrected these abnormalities in the cells of the ApoE-/- mice but not those of the DKO mice. In conclusion, TRα deletion in ApoE-/- mice slightly increases the expression of tRAS in the aorta and aggravates the dysregulation of cholesterol content in the VSMCs.

Therapeutic Role of Resveratrol and Quercetin on Aortic Fibroblasts of Psammomys obesus After Oxidative Stress by Hydrogen Peroxide.

In our study, we propose to analyze the effects of resveratrol (RES) and quercetin (QRC) on proliferation markers, oxidative stress, apoptosis, and inflammation of aortic fibroblasts of Psammomys obesus after induced oxidative stress by hydrogen peroxide (H2O2). Fibroblasts were incubated in RES 375 µM and QRC 0.083 µM for 24 hours after exposure to H2O2 1.2 mM for 6 hours. We performed the proliferation rate, cells viability, morphological analyses, cytochrome c, Akt, ERK1/2, and p38 MAPK quantification. The redox status was achieved by proportioning of malondialdehyde, nitric monoxide, advanced oxidation protein products, carbonyl proteins, catalase, and superoxide dismutase activity. The inflammation was measured by TNFα, MCP1, and NF-kB assay. The extracellular matrix (ECM) remodeling was performed by SDS-PAGE. Stressed fibroblasts showed a decrease of cell proliferation and viability, hypertrophy and oncosis, chromatin hypercondensation and increase of cytochrome c release characteristic of apoptosis, activation of ERK1/2 and Akt pathway, and decreases in p38 MAPK pathways marking the cellular resistance. The redox state was disrupted by increased malondialdehyde, nitric monoxide, advanced oxidation protein products, carbonyl protein production, catalase and superoxide dismutase activity, and a decreased production of proteins including collagens. Inflammation state was marked by MCP-1, TNFα, and NF-kB increase. Treatment of fibroblasts stressed by RES and QRC inverted the oxidative stress situation decreasing apoptosis and inflammation, and improving the altered redox status and rearrangement of disorders observed in extracellular matrix. H2O2 induced biochemical and morphological alterations leading to apoptosis. An improved general condition is observed after treatment with RES and QRC; this explains the antioxidant and antiapoptotic effects of polyphenols.

[Inflammation in the perivascular adipose tissue and atherosclerosis]. / Inflammation dans le tissu adipeux péri-artériel et athérome.

In atherosclerosis studies, there are few data, especially in men, on the biology of perivascular adipose tissue (PVAT) compared to that of other adipose tissue (AT), on amendments in obesity, and its possible role in the development of atherosclerosis. We conducted an ex vivo human study on pericarotid adipose tissue-collected in the immediate vicinity (PVATp) and away from the plate (tapas)-and subcutaneous (SC) neck gathered during surgery from patients suffering from atheromatous carotid disease. In addition, we conducted a study in obese Zucker rats (models of obesity and insulin resistance) and Wistar rats subjected to moderate stress. In these models, we collected renal adipose tissue (RAT), epididymal adipose tissue (EAT), and TAPA samples. On all samples, we measured mRNA levels encoding for proinflammatory cytokines (TNFα, IL-6, IL-1ß, MCP-1). Our results showed an increase in mRNA MCP-1, TNF and IL-6 in the adipose tissue around atherosclerotic plaques, an increase that was greater in diabetics than in non-diabetic subjects; we noted for the mRNA of MCP-1 in the TAPAp, 3.49×10-2±1.17×10-2ng/ug 18S in diabetic patients compared to 7.26×10-3±1.00×10-3ng/ug 18S (**P<0.01) in non-diabetic patients. In the obese Zucker rat, we found a significant increase in IL-6 in TAPA in obese animals compared to the corresponding controls (4.24×10-5±1.75×10-6ng/µg 18S vs 1.29×10-5±1.55×10-6ng/ug 18S). In stressed rats, we recorded a TNFα mRNA increase in the PVAT and EAT in the stressed rats compared to fatty tissue of control animals, we note respectively, 7.52×10-3±2.8×10-3ng/µg 18S vs 2.62×10-3±0.57×10-3ng/18S and 4.78×10-3±1.52×10-3ng/µg 18S vs 2.02×10-3±0.3×10-3ng/ug 18S. In summary, our work shows an inflammatory state of the TAPA surrounding the atheromatous plaques in diabetic patients. An obesity or stress state promotes an inflammatory profile of PVAT.

Glucotoxicity Induced Oxidative Stress and Inflammation In Vivo and In Vitro in Psammomys obesus: Involvement of Aqueous Extract of Brassica rapa rapifera.

Context. Brassica rapa is considered as natural source of antioxidants and is used to treat diabetes. Objective. Our study carried the impact of glucotoxicity induced in vivo and in vitro in vascular smooth muscle cells (VSMCs) in Psammomys and the therapeutic effect of Brassica rapa (AEBr). Materials and Methods. We administered a hyperglucidic diet (30% sucrose) for 9 months and a treatment for 20 days with AEBr at 100 mg/kg. VSMCs were submitted to D-Glucose (0.6%) for 48 hours and treated with AEBr (2100 µg/mL) for 24 hours. We measured, in blood metabolic parameters, the redox statues and inflammatory markers in adipose tissue. Histological study was effectuated in liver. In VSMCs, we measured markers of glucotoxicity (IRS1p Serine, AKT) inflammation (NO, MCP1, TNFα, and NF-κB) and oxidative stress (oxidants and antioxydants markers). Cell viability and apoptosis were estimated by the morphological study. Results. AEBr corrects the metabolic parameters and inflammatory and oxidative markers in blood and homogenate tissue and reduces lipid droplets in liver. It induces, in VSMCs, a significant decrease of IRS1p serine, cyt c, NO, MCP1, TNFα, NF-κB, protein, and lipid oxidation and increases cell viability, AKT, ERK1/2, catalase, and SOD activity. Conclusion. Brassica enhanced the antidiabetic, anti-inflammatory, and antioxidant defense leading to the protection of cardiovascular diseases.

Perilipin 1 ablation in mice enhances lipid oxidation during exercise and does not impair exercise performance.

Perilipin 1 is involved in the control of adipose tissue triacylglycerol hydrolysis. Its ablation in mice decreases fat mass and induces a partial resistance to diet-induced and genetic obesity. However, the consequences of perilipin 1 invalidation on energy balance are not fully defined. Moreover, the impact of perilipin 1 ablation on exercise performance and on fatty acids mobilization and utilization during exercise has not been studied. We compared energy balance (food intake, energy expenditure, spontaneous physical activity) and response to exercise of Plin1(-/-) and wild-type mice receiving a chow diet. The Plin1(-/-) mice had less fat, comparable food intake, comparable or slightly decreased energy expenditure, and no change in spontaneous physical activity. Mean 24-hour respiratory quotient was slightly lower, suggesting enhanced fatty acid oxidation. Exercise performance (both acute and endurance) was not impaired. Changes in nonesterified fatty acid levels during exercise were comparable, showing that triacylglycerol mobilization was unimpaired. Oxygen consumption increased faster (both tests) and to higher values (acute exercise) in Plin1(-/-) mice. Respiratory quotient increased during both types of exercise in Plin1(-/-) and control mice, but less in Plin1(-/-) mice. These lower respiratory quotient values show that Plin1(-/-) mice rely more on fatty acid oxidation during exercise. This is probably related to an overexpression in liver and muscle of genes for fatty acids oxidation. Perilipin 1 ablation has limited consequences on energy balance. It does not impair exercise performance; fatty acids mobilization during exercise is not impaired, whereas their oxidation is enhanced.

Increased atherosclerosis in mice deficient in perilipin1.

BACKGROUND: Perilipin1, a lipid droplet associated protein has an important role in the regulation of lipolysis and lipid storage in adipocytes. Perilipin1 is also expressed in foam cells of atheroma plaques and could therefore play a role in the accumulation of lipids in arterial wall and in the development of atherosclerosis. The aim of the study was to investigate this possible role of perilipin1 in atherogenesis. METHODS: Mice deficient in perilipin1 (Plin1-/-) were crossed with Ldlr-/- mice. Ldlr-/- and Plin1-/- Ldlr-/- mice received an atherogenic diet during 10 or 20 weeks. Blood pressure and plasma lipids concentrations were measured. Aortas were collected at the end of the atherogenic diet periods for quantification of atheroma lesions (en face method), histological and immunohistological studies RESULTS: Ldlr-/- and Plin1-/- Ldlr-/- mice had comparable blood pressure and plasma lipids levels. Plin1-/- Ldlr-/- mice had a lower body weight and decreased adiposity. The atherosclerotic lesion area in Plin1-/-Ldlr-/- mice was moderately increased after 10 weeks of atherogenic diet (ns) and significantly higher after 20 weeks (p < 0.01). Histology of atheroma plaques was comparable with no sign of increased inflammation in Plin1-/- Ldlr-/- mice. CONCLUSION: Perilipin1 ablation in mice results in increased atherosclerosis independently of modifications of risk factors such as raised blood pressure or plasma lipids levels. These data strongly support an atheroprotective role for perilipin1.