Cardiac remodeling associated with chronic kidney disease is enhanced in a rat model of metabolic syndrome: Preparation of mesenchymal transition.

Cardiac alteration due to chronic kidney disease is described by tissue fibrosis. This remodeling involves myofibroblasts of various origins, including epithelial or endothelial to mesenchymal transitions. In addition, obesity and insulin resistance together or separately seem to exacerbate cardiovascular risk in chronic kidney disease (CKD). The main objective of this study was to assess if pre-existing metabolic disease exacerbates CKD-induced cardiac alterations. In addition, we hypothesised that endothelial to mesenchymal transition participates in this enhancement of cardiac fibrosis. Rats fed cafeteria type diet for 6 months underwent a subtotal nephrectomy at 4 months. Cardiac fibrosis was evaluated by histology and qRT-PCR. Collagens and macrophages were quantified by immunohistochemistry. Endothelial to mesenchymal transitions were assessed by qRT-PCR (CD31, VE-cadherin, α-SMA, nestin) and also by CD31 immunofluorescence staining. Rats fed with cafeteria type regimen were obese, hypertensive and insulin resistant. Cardiac fibrosis was predominant in CKD rats and was highly majored by cafeteria regimen. Collagen-1 and nestin expressions were higher in CKD rats, independently of regimen. Interestingly, in rats with CKD and cafeteria diet we found an increase of CD31 and α-SMA co-staining with suggest an implication of endothelial to mesenchymal transition during heart fibrosis. We showed that rats already obese and insulin resistant had an enhanced cardiac alteration to a subsequent renal injury. Cardiac fibrosis process could be supported by a involvement of the endothelial to mesenchymal transition phenomenon.

Vitamin D3 Supplementation Alleviates Left Ventricular Dysfunction in a Mouse Model of Diet-Induced Type 2 Diabetes: Potential Involvement of Cardiac Lipotoxicity Modulation.

PURPOSE: To evaluate the effectiveness of vitamin D3 supplementation, in secondary prevention, on cardiac remodeling and function, as well as lipid profile, in a mouse model of diet-induced type 2 diabetes. METHODS: Mice were fed a high fat and sucrose diet for 10 weeks. Afterward, diet was maintained for 15 more weeks and two groups were formed, with and without cholecalciferol supplementation. A control group was fed with normal chow. Glucose homeostasis and cardiac function were assessed at baseline and at the 10th and 24th weeks. Animals were killed at the 10th and 25th weeks for plasma and cardiac sample analysis. Cardiac lipid profile was characterized by LC-MS/MS. RESULTS: After 10 weeks of diet, mice exhibited pre-diabetes, mild left ventricle hypertrophy, and impaired longitudinal strain, but preserved myocardial circumferential as well as global diastolic and systolic cardiac function. After 15 more weeks of diet, animals presented with well-established type 2 diabetes, pathological cardiac hypertrophy, and impaired regional myocardial function. Cholecalciferol supplementation had no effect on glucose homeostasis but improved cardiac remodeling and regional myocardial function. After 25 weeks, non-supplemented mice exhibited increased myocardial levels of ceramides and diacylglycerol, both of which were normalized by vitamin D3 supplementation. CONCLUSION: This work brought to light the beneficial effects of cholecalciferol supplementation, in secondary prevention, on cardiac remodeling and function in a mouse model of diet-induced type 2 diabetes. Those cardioprotective effects may be, at least in part, attributed to the modulation of myocardial levels of lipotoxic species by vitamin D.

Prevention of vascular calcification by the endogenous chromogranin A-derived mediator that inhibits osteogenic transdifferentiation.

The adrenal glands participate in cardiovascular (CV) physiology and the pathophysiology of CV diseases through their effects on sodium and water metabolism, vascular tone and cardiac function. In the present study, we identified a new adrenal compound controlling mesenchymal cell differentiation that regulates osteoblastic differentiation in the context of vascular calcification. This peptide was named the "calcification blocking factor" (CBF) due to its protective effect against vascular calcification and is released from chromogranin A via enzymatic cleavage by calpain 1 and kallikrein. CBF reduced the calcium content of cells and thoracic aortic rings under calcifying culture conditions, as well as in aortas from animals treated with vitamin D and nicotine (VDN animals). Furthermore, CBF prevented vascular smooth muscle cell (VSMC) transdifferentiation into osteoblast-like cells within the vascular wall via the sodium-dependent phosphate transporter PIT-1 and by inhibition of NF-κB activation and the subsequent BMP2/p-SMAD pathway. Pulse pressure, a marker of arterial stiffness, was significantly decreased in VDN animals treated with CBF. In line with our preclinical data, CBF concentration is significantly reduced in diseases characterized by increased calcification, as shown in patients with chronic kidney disease. In preparation for clinical translation, the active site of the native 19-AS long native CBF was identified as EGQEEEED. In conclusion, we have identified the new peptide CBF, which is secreted from the adrenal glands and might prevent vascular calcification by inhibition of osteogenic transdifferentiation. The anti-calcific effects of CBF and short active site may therefore promote the development of new tools for the prevention and/or treatment of vascular calcification.

Murine double minute-2 mediates exercise-induced angiogenesis in adipose tissue of diet-induced obese mice.

OBJECTIVE: This study aimed to determine the effects of physical exercise on the angio-adaptive response in adipose tissue following weight loss in a mouse model of diet-induced obesity. We hypothesized that physical exercise stimulates angiogenesis through the regulation of Vascular endothelial growth factor-A (VEGF-A) pro-/Thrombospondin-1 (TSP-1) anti-angiogenic signal under the control of the Murine double-minute 2/Forkhead box Os (Mdm2/FoxOs) axis, as reported in skeletal muscle. METHODS: We studied the effects of 7 weeks-voluntary exercise (Ex) in C57Bl/6 control or diet-induced obese (HFS) mice on vascularization of white adipose tissue (AT). RESULTS: Diet-induced obese sedentary (HFSsed) mice presented a powerful angiostatic control in all adipose tissues, under FoxOs protein regulation, leading to capillary rarefaction. Exercise increased expression of Mdm2, repressing the angiostatic control in favor of adipose vascular regrowth in normal chow (NCex) and HFSex mice. This phenomenon was associated with adipocytes microenvironment improvement, such as decreased adipocytes hypertrophy and adipose tissue inflammation. In addition, adipose angiogenesis stimulation by exercise through Mdm2 pro-angiogenic action, improved visceral adipose insulin sensitivity, activated browning process within subcutaneous adipose tissue (ScWAT) and decreased ectopic fat deposition (muscle, heart and liver) in obese HFSex mice. The overall result of this approach of therapy by physical exercise is an improvement of all systemic cardiometabolic parameters. CONCLUSIONS: These data demonstrated the therapeutic efficacy of physical exercise against obesity-associated pathologies, and also offer new prospects for molecular therapies targeting the adipose angio-adaptation in obese humans.

High dietary intake of palm oils compromises glucose tolerance whereas high dietary intake of olive oil compromises liver lipid metabolism and integrity.

PURPOSE: Palm (PO) and olive oils (OO) are the two most consumed and/or used oils in the world for food elaboration. These oils should not be confused with the solid palm stearin which is widely used in pastry making. Large number of studies was reported dealing with adverse/beneficial cardiovascular effects of PO and OO, whereas few studies were conducted to compare their potential effects on hepatic steatosis and liver lipid metabolism. The aim of this study was to compare the metabolic effects of high intake of POs (both crude and refined) and virgin OO on surrogate parameters of glucose tolerance, hepatic lipid metabolism and liver integrity. METHODS: Thirty-two young male Wistar rats were divided into four equal groups and fed either control diet (11% energy from fat) or three high-fat diets rich in crude or refined POs or in OO (56% energy from fat), during 12 weeks. Systemic blood and liver biochemical parameters linked to glucose and lipid metabolism as well as hepatic steatosis and liver fatty acid composition were explored. The inflammation and oxidative stress status as well as the expression of several genes/proteins were also analyzed. RESULTS: The major effects of POs intake concerned glucose metabolism and liver fatty acid composition, whereas the major effects of OO intake concerned hepatic TG accumulation, inflammation, and cytolysis. CONCLUSIONS: In conclusion, high dietary intake of PO compromises glucose tolerance whereas high dietary intake of OO compromises hepatic lipid composition and liver integrity. However, adverse hepatic effects of OO observed in this study may not be transposed to human since, (a) the rodent model could lead to different effects than those observed in humans and (b) the average normal OO amounts ingested in the population are lower than those corresponding to a high-fat diet. So, further studies are needed to determine a maximum non-invasive dietary intake of OO.

sST2 as a New Biomarker of Chronic Kidney Disease-Induced Cardiac Remodeling: Impact on Risk Prediction.

Heart failure is the most frequent cardiac complication of chronic kidney disease (CKD). Biomarkers help identify high-risk patients. Natriuretic peptides (BNP and NT-proBNP) are largely used for monitoring patients with cardiac failure but are highly dependent on glomerular filtration rate (GFR). Soluble suppression of tumorigenicity 2 (sST2) biomarker is well identified in risk stratification of cardiovascular (CV) events in heart failure. Furthermore, sST2 is included in a bioclinical score to stratify mortality risk. The aims of this study were to evaluate (i) the interest of circulating sST2 level in heart dysfunction and (ii) the bioclinical score (Barcelona Bio-Heart Failure risk calculator) to predict the risk of composite outcome (major adverse coronary events) and mortality in the CKD population. A retrospective study was carried out on 218 CKD patients enrolled from 2004 to 2015 at Montpellier University Hospital. sST2 was measured by ELISA (Presage ST2® kit). GFR was estimated by the CKD-EPI equation (eGFR). Indices of cardiac parameters were performed by cardiac echography. No patient had reduced ejection fraction. 112 patients had left ventricular hypertrophy, and 184 presented cardiac dysfunction, with structural, functional abnormalities or both. sST2 was independent of age and eGFR (ρ = 0.05, p = 0.44, and ρ = -0.07, p = 0.3, respectively). Regarding echocardiogram data, sST2 was correlated with left ventricular mass index (ρ = 0.16, p = 0.02), left atrial diameter (ρ = 0.14, p = 0.04), and volume index (ρ = 0.13, p = 0.05). sST2 alone did not change risk prediction of death and/or CV events compared to natriuretic peptides. Included in the Barcelona Bio-Heart Failure (BCN Bio-HF) score, sST2 added value and better stratified the risk of CV events and/or death in CKD patients (p < 0.0001). To conclude, sST2 was associated with cardiac remodeling independently of eGFR, unlike other cardiac biomarkers. Added to the BCN Bio-HF score, the risk stratification of death and/or CV events in nondialyzed CKD patients was highly improved.

Sodium restriction modulates innate immunity and prevents cardiac remodeling in a rat model of metabolic syndrome.

In the view of the relationships between excessive sodium intake, immunity and target organ damage, we hypothesized that reduction in dietary sodium would be beneficial in the prevention of cardiac alterations through a restrained local immunity response in a rat model of metabolic syndrome. Sprague-Dawley rats were fed a 60% fructose diet with either a normal sodium (0.64% NaCl) or a low sodium content (<0.01% NaCl) for 8weeks. After 4weeks, rats were infused or not with angiotensin II (200ng·kg-1·min-1, sc) for 4weeks. Tail-cuff blood pressure was determined in conscious rats. Heart and left ventricle weight, cardiomyocyte size, and cardiac fibrosis were evaluated. We performed a transcriptomic analysis in order to identify differentially regulated cardiac mRNAs between normal and low sodium diets. We validated those results using qPCR and immunohistochemistry. Angiotensin II-induced blood pressure rise was blunted (~50%) in the low-sodium fed rats while cardiac hypertrophy and fibrosis were prevented. Transcriptomic analysis revealed 66 differentially regulated genes including 13 downregulated genes under the low sodium diet and implicated in the innate immune response. This was confirmed by reduced cardiac macrophages infiltration under the low sodium diet. Dietary sodium restriction prevents structural alterations of the heart of rats with fructose-induced insulin resistance and angiotensin II-hypertension. The reduction of cardiac inflammation and macrophage infiltration suggests that innate immunity has an important role in the beneficial effect of sodium restriction on cardiac remodeling.

Carbon monoxide increases inducible NOS expression that mediates CO-induced myocardial damage during ischemia-reperfusion.

We investigated the role of inducible nitric oxide (NO) synthase (iNOS) on ischemic myocardial damage in rats exposed to daily low nontoxic levels of carbon monoxide (CO). CO is a ubiquitous environmental pollutant that impacts on mortality and morbidity from cardiovascular diseases. We have previously shown that CO exposure aggravates myocardial ischemia-reperfusion (I/R) injury partly because of increased oxidative stress. Nevertheless, cellular mechanisms underlying cardiac CO toxicity remain hypothetical. Wistar rats were exposed to simulated urban CO pollution for 4 wk. First, the effects of CO exposure on NO production and NO synthase (NOS) expression were evaluated. Myocardial I/R was performed on isolated perfused hearts in the presence or absence of S-methyl-isothiourea (1 µM), a NOS inhibitor highly specific for iNOS. Finally, Ca(2+) handling was evaluated in isolated myocytes before and after an anoxia-reoxygenation performed with or without S-methyl-isothiourea or N-acetylcystein (20 µM), a nonspecific antioxidant. Our main results revealed that 1) CO exposure altered the pattern of NOS expression, which is characterized by increased neuronal NOS and iNOS expression; 2) cardiac NO production increased in CO rats because of its overexpression of iNOS; and 3) the use of a specific inhibitor of iNOS reduced myocardial hypersensitivity to I/R (infarct size, 29 vs. 51% of risk zone) in CO rat hearts. These last results are explained by the deleterious effects of NO and reactive oxygen species overproduction by iNOS on diastolic Ca(2+) overload and myofilaments Ca(2+) sensitivity. In conclusion, this study highlights the involvement of iNOS overexpression in the pathogenesis of simulated urban CO air pollution exposure.

Endogenous antioxidant defense induction by melon superoxide dismutase reduces cardiac hypertrophy in spontaneously hypertensive rats.

We assessed the influence of SODB, a melon superoxide dismutase (SOD), on left ventricular (LV) hypertrophy in SHR. SODB (4 or 40U SOD) was given orally for 4 or 28 days to SHR. For each treatment period, LV weight index (LVWI) and cardiomyocytes size were measured. SOD, glutathione peroxidase (GPx) and catalase expressions, and LV production and presence of superoxide anion were determined. Pro-inflammatory markers were also measured. SODB reduced LVWI and cardiomyocytes size after 4 or 28 days. Cardiac SOD and GPx increased by 30-40% with SODB. The presence but not production of superoxide anion was significantly reduced by SODB. No effect of SODB was detected on inflammatory status in any group. The beneficial effect of SODB on cardiac hypertrophy seems to be related to the stimulation of endogenous antioxidant defense, suggesting that SODB may be of interest as a dietary supplementation during conventional antihypertensive therapy.

Dietary sodium restriction prevents kidney damage in high fructose-fed rats.

Sodium depletion has a protective effect on target-organ damage in hypertension independent of blood pressure. Here we tested whether chronic dietary sodium restriction may prevent the development of renal alterations associated with insulin resistance by reducing the inflammatory and oxidant state. Rats were fed normal-salt-60% fructose, low-salt-60% fructose, or control normal-salt diet for 12 weeks. Insulin resistance induced by high-fructose diet was associated with an increase in albuminuria, tubular and glomerular hypertrophy, and inflammation of kidney and adipose tissue. The low-salt diet improved insulin sensitivity and prevented kidney damage. These beneficial effects of sodium depletion were associated with a decrease in renal inflammation (macrophage infiltration, IL-6, TNF-α) and oxidative stress (NADPH oxidase activity), and a prevention of histologic changes in retroperitoneal fat induced by high fructose. Thus, dietary salt depletion has beneficial effects on renal and metabolic alterations associated with a high-fructose diet in rats.

Cafeteria Diet-Induced Obesity Worsens Experimental CKD.

Obesity is a significant risk factor for chronic kidney disease (CKD). This study aimed to evaluate the impact of obesity on the development of kidney fibrosis in a model of cafeteria diet rats undergoing 5/6th nephrectomy (SNx). Collagen 1, 3, and 4 expression, adipocyte size, macrophage number, and the expression of 30 adipokines were determined. Collagen 1 expression in kidney tissue was increased in Standard-SNx and Cafeteria-SNx (7.1 ± 0.6% and 8.9 ± 0.9 tissue area, respectively). Renal expression of collagen 3 and 4 was significantly increased (p < 0.05) in Cafeteria-SNx (8.6 ± 1.5 and 10.9 ± 1.9% tissue area, respectively) compared to Cafeteria (5.2 ± 0.5 and 6.3 ± 0.6% tissue area, respectively). Adipocyte size in eWAT was significantly increased by the cafeteria diet. In Cafeteria-SNx, we observed a significant increase in macrophage number in the kidney (p = 0.01) and a consistent tendency in eWAT. The adipokine level was higher in the Cafeteria groups. Interleukin 11, dipeptidyl peptidase 4, and serpin 1 were increased in Cafeteria-SNx. In the kidney, collagen 3 and 4 expressions and the number of macrophages were increased in Cafeteria-SNx, suggesting an exacerbation by preexisting obesity of CKD-induced renal inflammation and fibrosis. IL11, DPP4, and serpin 1 can act directly on fibrosis and participate in the observed worsening CKD.

Implications of Senescent Cell Burden and NRF2 Pathway in Uremic Calcification: A Translational Study.

Increased senescent cell burden and dysregulation of the nuclear factor erythroid 2-related factor 2 (NRF2) pathway have been associated with numerous age-related pathologies; however, their role in promoting vascular calcification (VC) in chronic kidney disease (CKD) has yet to be determined. We investigated whether senescence and NRF2 pathways may serve as drivers of uremia-induced VC using three complementary approaches: a novel model of induced VC in 5/6-nephrectomized rats supplemented with high phosphate and vitamin D; epigastric arteries from CKD patients with established medial calcification; and vascular smooth muscle cells (VSMCs) incubated with uremic serum. Expression of p16Ink4a and p21Cip1, as well as γ-H2A-positive cells, confirmed increased senescent cell burden at the site of calcium deposits in aortic sections in rats, and was similarly observed in calcified epigastric arteries from CKD patients through increased p16Ink4a expression. However, uremic serum-induced VSMC calcification was not accompanied by senescence. Expression of NRF2 and downstream genes, Nqo1 and Sod1, was associated with calcification in uremic rats, while no difference was observed between calcified and non-calcified EAs. Conversely, in vitro uremic serum-driven VC was associated with depleted NRF2 expression. Together, our data strengthen the importance of senescence and NRF2 pathways as potential therapeutic options to combat VC in CKD.

Vascular calcification in different arterial beds in ex vivo ring culture and in vivo rat model.

Vascular calcification is a risk factor for cardiovascular and kidney diseases. Medial calcification may differently affect the arterial tree depending on vessel location and smooth muscle injury. The aim was to map the anatomical distribution of vascular calcifications on different arteries and artery locations, in cultured artery rings (ex vivo) and in a rat model of elastocalcinosis (in vivo). Vascular calcification was assessed histologically (von Kossa staining of the media) and by calcium content measurement. Arteries of different sizes were harvested from untreated rats for ring culture and from the vitamin D3-nicotine (VDN) rat model for direct observation. When cultured in pro-calcifying conditions, thoracic aorta exhibited similar calcification from the arch to the diaphragm. Calcification increased in abdominal aorta along with the reduction in cross sectional area. Carotid and renal arteries exhibited similar ex vivo calcification. In VDN rats, calcification was greater in carotid artery than in aorta, and was accompanied by fibrosis and apoptosis. Ex vivo, calcification was increased by the induction of lesions on arteries. Along the vascular tree, calcification of the arterial wall increases with the narrowing of vessels in ex vivo ring culture and in vivo. The observed differences represent local susceptibility of the vessels to the calcifying processes.

Diets Rich in Olive Oil, Palm Oil, or Lard Alter Mitochondrial Biogenesis and Mitochondrial Membrane Composition in Rat Liver.

Palm oil (crude or refined) and lard are rich in SFA, while olive oil is rich in polyunsaturated fatty acids. SFA are considered harmful to health, while polyunsaturated fatty acids are beneficial to health. The aim of this study was to determine the effect of diets rich in crude PO, refined PO, OO, or lard on the mitochondrial membrane, the activity of mitochondrial respiratory chain complexes, and mitochondrial biogenesis. This was an experimental study in male Wistar rats fed a diet containing 30% of each oil. Rats had free access to food and water. After being fed for 12 weeks, animals were sacrificed and liver mitochondria were collected. This collection was used to determine membrane potential and ROS production, membrane phospholipid and fatty acid composition, citrate synthase activity and respiratory chain complex, cardiolipin synthase protein expression, and expression of selected genes involved in mitochondrial biogenesis. We found that diets rich in olive oil, palm oil, or lard altered mitochondrial biogenesis by significantly decreasing Pgc1α gene expression and altered the fatty acid composition of rat liver mitochondrial membrane PL.

Grape polyphenols and exercise training have distinct molecular effects on cardiac hypertrophy in a model of obese insulin-resistant rats.

Obesity and exercise lead to structural changes in heart such as cardiac hypertrophy. The underlying signaling pathways vary according to the source of the overload, be it physiological (exercise) or pathologic (obesity). The physiological pathway relies more on PI3K-Akt signaling while the pathologic pathway involves calcineurin-Nuclear factor of activated T-cells activation and fibrosis accumulation. Independently, exercise and polyphenols have demonstrated to prevent pathologic cardiac hypertrophy. Therefore, we investigated the molecular adaptations of the combination of exercise training and grape polyphenols supplementation (EXOPP) in obese high-fat fed rats on heart adaptation in comparison to exercise (EXO), polyphenols supplementation (PP) and high-fat fed rats (HF), alone. Exercised and PP rats presented a higher heart weight/body weight ratio compared to HF rats. EXO and EXOPP depicted an increase in cell-surface area, P-Akt/Akt, P-AMPK/AMPK ratios with a decreased fibrosis and calcineurin expression, illustrating an activation of the physiological pathway, but no additional benefit of the combination. In contrast, neither cell-surface area nor Akt signaling increased in PP rats; but markedly decreased fibrosis, calcineurin expression, systolic blood pressure, higher SERCA and P-Phospholamdan/Phospholamdan levels were observed. These data suggest that PP rats have a shift from pathologic toward physiological hypertrophy. Our study demonstrates that polyphenols supplementation has physical-activity-status-specific effects; it appears to be more protective in sedentary obese insulin-resistant rats than in the exercised ones. Exercise training improved metabolic and cardiac alterations without a synergistic effect of polyphenols supplementation. These data highlight a greater effect of exercise than polyphenols supplementation for the treatment of cardiac alterations in obese insulin-resistant rats.

Peripancreatic Adipose Tissue Remodeling and Inflammation during High Fat Intake of Palm Oils or Lard in Rats.

Excessive fat consumption leads to the development of ectopic adipose tissues, affecting the organs they surround. Peripancreatic adipose tissue is implicated in glucose homeostasis regulation and can be impaired in obesity. High palm oil consumption's effects on health are still debated. We hypothesised that crude and refined palm oil high-fat feeding may have contrasting effects on peripancreatic adipocyte hypertrophy, inflammation and lipid oxidation compound production in obese rats. In Wistar rats, morphological changes, inflammation and isoprostanoid production following oxidative stress were assessed in peripancreatic adipose tissue after 12 weeks of diets enriched in crude or refined palm oil or lard (56% energy from fat in each case) versus a standard chow diet (11% energy from fat). Epididymal white and periaortic brown adipose tissues were also included in the study. A refined palm oil diet disturbed glucose homeostasis and promoted lipid deposition in periaortic locations, as well as adipocyte hypertrophy, macrophage infiltration and isoprostanoid (5-F2c-isoprostane and 7(RS)-ST-Δ8-11-dihomo-isofuran) production in peripancreatic adipose tissue. Crude palm oil induced a lower impact on adipose deposits than its refined form and lard. Our results show that the antioxidant composition of crude palm oil may have a protective effect on ectopic adipose tissues under the condition of excessive fat intake.

Effects of high-fat diets on inflammation and antioxidant status in rats : comparison between palm olein and olive oil.

Palm olein (PO) and olive oil (OO) are widely consumed in the world. PO is considered harmful to health, whereas OO is considered healthy. The aim of the study was to compare the effects of consumption of these oils on antioxidant status and inflammation in rats. This was an experimental study in male wistar rats fed a diet containing 30% of each oil. Rats had free access to food and water. After being fed for 12 weeks, animals were sacrificed and liver and aortic blood were collected. Plasma was used for the determination of interleukin-6 (IL-6) and oxidative stress parameters (Superoxide dismutase -SOD; Gluthation peroxidase - GPx; Thiobarbituric acid reactive substances - TBARS; Thiol groups and isoprostane). The inflammation and oxidative stress status as well as the expression of several genes/proteins were also analyzed in liver homogenate. No significant differences were observed between PO and OO in plasma and liver levels of the studied inflammation and oxidative stress parameters. This study showed that the consumption of PO induces an antioxidant status superimposable to that of OO.   Key words : Palm olein - Olive oil - Oxidative stress - Inflammation - High fat diet.

Supplementation with a Bioactive Melon Concentrate in Humans and Animals: Prevention of Oxidative Damages and Fatigue in the Context of a Moderate or Eccentric Physical Activity.

Exercise is recognized to provide both physical and psychological health benefits. However, oxidative stress can occur and induce muscular damages. SOD B® M is a melon concentrate, well known to counteract oxidative stress and prevent its side effects. The present study aimed to evaluate the potential of the melon concentrate in the context of both a strong and isolated effort associated with deleterious effects, and a moderate and regular physical activity considered as beneficial. First, a preclinical study was set up on rats to evaluate its potential on the prevention of damages induced by an eccentric exercise. Secondly, the combined effect of the melon concentrate and a regular standardized physical training was studied on the overall physical condition of healthy subjects in a randomized, double-blind, placebo-controlled trial. Repeated measures Analysis of Variance (ANOVA), student's t test and Mann-Whitney test were used for statistical analyses. Melon concentrate helped to prevent gastrocnemius damages induced by the eccentric exercise. It allowed a reduction of fibrosis by approximately 38% and a reduction of Tumor Necrosis Factor- α (TNF-α) plasma level by 28%. This supplementation also induced a rearrangement of myosin fibers and an increase in PGC-1α plasma level. In the clinical study, melon concentrate was able to decrease oxidative stress and C-Reactive protein (CRP) plasma level. Besides, magnesium (Mg) plasma level was higher in the context of a regular training performed by healthy subjects supplemented with the melon concentrate. Therefore, the melon concentrate allowed a better adaptation to effort linked to PGC-1α activation: a regulator of energy metabolism. The antioxidant properties of the melon concentrate and its ability to mobilize magnesium also suggest that the supplementation could induce a better resistance to fatigue and recovery during regular physical activity.

Optimisation of cell and ex vivo culture conditions to study vascular calcification.

Medial vascular calcification (MVC) is a highly prevalent disease associated with a high risk of severe, potentially lethal, complications. While animal studies may not systematically be circumvented, in vitro systems have been proven useful to study disease physiopathology. In the context of MVC, the absence of a clinically relevant standardized in vitro method prevents the appropriate comparison and overall interpretation of results originating from different experiments. The aim of our study is to establish in vitro models mimicking in vivo vascular calcification and to select the best methods to unravel the mechanisms involved in MVC. Human aortic smooth muscle cells and rat aortic rings were cultured in different conditions. The influence of fetal calf serum (FCS), alkaline phosphatase, phosphate and calcium concentrations in the medium were evaluated. We identified culture conditions, including the herein reported Aorta Calcifying Medium (ACM), which allowed a reproducible and specific medial calcification of aortic explants. Studying cells and aortic explants cultured, the involvement of bone morphogenetic protein 2 (BMP2) pathway, fibrosis and apoptosis processes in in vitro MVC were demonstrated. Expression of osteoblastic markers was also observed suggesting the occurrence of transdifferentiation of smooth muscle cells to osteoblasts in our models. The use of these models will help researchers in the field of vascular calcification to achieve reproducible results and allow result comparison in a more consistent way.

Effect of spirulina and silicon-enriched spirulina on metabolic syndrome features, oxidative stress and mitochondrial activity in Zucker fatty rats.

The use of Spirulina platensis (Sp) as a functional food was suggested decades ago. Biological incorporation of Silicon (Si) into Sp increases its bioavailability for potential food supplement applications. This work aimed at determining the effects of Sp and Si-enriched Sp (Sp+Si) on metabolic syndrome features in Zucker fatty rats. Thirty Zucker fatty rats were divided into three groups and supplemented with placebo or Sp or Sp+Si croquettes for 12 weeks. Food consumption, glucose intolerance, hepatic steatosis, and mitochondrial and oxidative stress were determined. Zucker fatty rats exhibited several hepatic metabolic alterations as well as mitochondrial and oxidative stress perturbations. The intake of Sp increased plasma TG levels and decreased the hepatic NADPH oxidase activity and ameliorated transitorily the glucose intolerance. However, Si-spirulina does not appear to have more beneficial effects than spirulina alone. Other experiments with different species of rats/mice, different diets, or durations of diet intake should be undertaken to confirm or infirm these results. PRACTICAL APPLICATIONS: Glucose intolerance and hepatic steatosis, two major components of metabolic syndrome, are increasing and becomes a major public health issue. Use of Spirulina platensis (Sp) as a functional food was suggested as a protein-dense food source. Bioavailable silicon (Si) may be an essential nutrient for higher animals, including humans. Sp but not Sp+Si decreased liver NADPH oxidase activity and improved transitorily glucose tolerance. This is the first study where Sp and Sp+Si effect on glucose intolerance is reported in Zucker rat. Other experiments should be undertaken to confirm or infirm invalidate the beneficial effects of Sp+Si supplement in the metabolic syndrome features.