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.

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.

S-Ethyl-Isothiocitrullin-Based Dipeptides and 1,2,4-Oxadiazole Pseudo-Dipeptides: Solid Phase Synthesis and Evaluation as NO Synthase Inhibitors.

We previously reported dipeptidomimetic compounds as inhibitors of neuronal and/or inducible NO synthases (n/iNOS) with significant selectivity against endothelial NOS (eNOS). They were composed of an S-ethylisothiocitrullin-like moiety linked to an extension through a peptide bond or a 1,2,4-oxadiazole link. Here, we developed two further series where the extension size was increased to establish more favorable interactions in the NOS substrate access channel. The extension was introduced on the solid phase by the reductive alkylation of an amino-piperidine moiety or an aminoethyl segment in the case of dipeptide-like and 1,2,4-oxadiazole compounds, respectively, with various benzaldehydes. Compared to the previous series, more potent inhibitors were identified with IC50 in the micromolar to the submicromolar range, with significant selectivity toward nNOS. As expected, most compounds did not inhibit eNOS, and molecular modeling was carried out to characterize the reasons for the selectivity toward nNOS over eNOS. Spectral studies showed that compounds were interacting at the heme active site. Finally, selected inhibitors were found to inhibit intra-cellular iNOS and nNOS expressed in RAW264.7 and INS-1 cells, respectively.

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.

Experimental Models to Study Endothelial to Mesenchymal Transition in Myocardial Fibrosis and Cardiovascular Diseases.

Fibrosis is a common feature of cardiovascular diseases and targets multiple organs, such as the heart and vessels. Endothelial to mesenchymal transition is a complex, vital process that occurs during embryonic formation and plays a crucial role in cardiac development. It is also a fundamental process implicated in cardiac fibrosis and repair, but also in other organs. Indeed, in numerous cardiovascular diseases, the endothelial-to-mesenchymal transition has been shown to be involved in the generation of fibroblasts that are able to produce extracellular matrix proteins such as type I collagen. This massive deposition results in tissue stiffening and organ dysfunction. To advance our understanding of this process for the development of new specific diagnostic and therapeutic strategies, it is essential to develop relevant cellular and animal models of this process. In this review, our aim was to gain an in-depth insight into existing in vitro and in vivo models of endothelial to mesenchymal transition in cardiovascular diseases with a focus on cardiac fibrosis. We discuss important parameters impacting endothelial to mesenchymal transition, and we give perspectives for the development of relevant models to decipher the underlying mechanisms and ultimately find new treatments specific to fibrosis happening in cardiovascular diseases.

Addressing the quality challenge of a human biospecimen biobank through the creation of a quality management system.

BACKGROUND: The objective of the COMET (COllection of MEtabolic Tissues) biobank project is to create a high-quality collection of insulin-sensitive tissues (liver, muscle, adipose tissues, and epiploic artery) and blood sample derivatives (plasma, serum, DNA and RNA), collected from 270 grade 2-3 obese patients undergoing bariatric surgery. Relevant data on patient such as clinical/biological characteristics and sample handling are also collected. For this, our aim was to establish a Quality Management System (QMS) to meet the reliability and quality requirements necessary for its scientific exploitation. MATERIALS AND METHODS: The COMET QMS includes: (1) Quality Assurance to standardize all stages of the biobanking process, (2) Quality Controls on samples from the first patients included in order to validate the sample management process and ensure reproducible quality; and 3) "in process" Quality Controls to ensure the reliability of the storage procedures and the stability of the samples over time. RESULTS: For serum and plasma, several corrective actions, such as temperature handling and centrifugation conditions, were made to the protocol and led to improvement of the volume and quality of samples. Regarding DNA, all samples evaluated achieved a satisfactory level of purity and integrity and most of them yielded the required DNA quantity. All frozen tissue samples had RNAs of good purity. RNA quality was confirmed by RIN, achieving values in most cases over 7 and efficient amplification of housekeeping genes by RT-qPCR, with no significant differences among samples from the same tissue type. In the "in process" Quality Controls, DNA, RNA, and histological integrity of tissues showed no differences among samples after different preservation times. CONCLUSION: Quality Control results have made it possible to validate the entire biobank process and confirm the utility of implementing QMS to guarantee the quality of a biospecimen collection.

Reduced production of isoprostanes by peri-pancreatic adipose tissue from Zucker fa/fa rats as a new mechanism for ß-cell compensation in insulin resistance and obesity.

During early stages of type 2 diabetes, named prediabetes, pancreatic ß-cells compensate for insulin resistance through increased insulin secretion in order to maintain normoglycemia. Obesity leads to the development of ectopic fat deposits, among which peri-pancreatic white adipose tissue (pWAT) can communicate with ß-cells through soluble mediators. Thus we investigated whether pWAT produced oxygenated lipids, namely isoprostanes and neuroprostanes and whether they can influence ß-cell function in obesity. In the Zucker fa/fa rat model, pWAT and epididymal white adipose tissue (eWAT) displayed different inflammatory profiles. In obese rats, pWAT, but not eWAT, released less amounts of 5-F2t-isoprostanes, 15-F2t-isoprostanes, 4-F4t-neuroprostanes and 10-F4t-neuroprostane compared to lean animals. These differences could be explained by a greater induction of antioxidant defenses enzymes such as SOD-1, SOD-2, and catalase in pWAT of obese animals compared to eWAT. In addition, sPLA2 IIA, involved in the release of isoprostanoids from cellular membranes, was decreased in pWAT of obese animals, but not in eWAT, and may also account for the reduced release of oxidized lipids by this tissue. At a functional level, 15-F2t-isoprostane epimers, but not 5-F2t-isoprostanes, were able to decrease glucose-induced insulin secretion in pancreatic islets from Wistar rats. This effect appeared to be mediated through activation of the thromboxane A2 receptor and reduction of cAMP signaling in pancreatic islets. In conclusion, through the removal of an inhibitory tone exerted by isoprostanes, we have shown, for the first time, a new mechanism allowing ß-cells to compensate for insulin resistance in obesity that is linked to a biocommunication between adipose tissue and ß-cells.

The triglycerides and glucose (TyG) index: A new marker associated with nonalcoholic steatohepatitis (NASH) in obese patients.

AIM: Diagnosis of nonalcoholic steatohepatitis (NASH) relies on liver biopsy. Noninvasive tools would be useful to target patients to refer for a biopsy. We aimed to determine the diagnostic value of the triglycerides and glucose (TyG) index, an insulin-resistance indicator, to predict NASH. METHODS: Our study included grade II-III obese patients aged 18-65 years undergoing bariatric surgery and included in the COMET (COllection of MEtabolic Tissues) biobank (NCT02861781). Liver biopsies performed during bariatric surgery were collected from the biobank along with blood derivatives. Biopsies were analysed according to the steatosis, activity and fibrosis (SAF) scoring system to diagnose NASH, nonalcoholic fatty liver disease (NAFLD), and fibrosis. Logistic regression models were performed to identify factors predicting NASH, NAFLD, and fibrosis. RESULTS: Of 238 analysed subjects (mean age 43±12 years, 33.6% men), 29% had type 2 diabetes. Steatosis was present in 67.2%, while NASH and advanced fibrosis (stage F3) were diagnosed in 18.1% and 2.9% respectively. TyG index was independently associated with NASH (odds ratio (OR): 4.7 [95% confidence interval: 2.3;9.5] P < 0.0001), NAFLD (OR: 2.0 [1.1;3.7] P = 0.03) and stages 2-3 fibrosis (OR: 4.0 [1.5;10.8] P = 0.007). NASH was also predicted by gamma-glutamyl transferase (GGT) with an area under the ROC curve: 0.79 [0.71;0.87 P = 0.04] for GGT and TyG index combined. CONCLUSION: In our cohort of severely obese patients, TyG index, when associated with GGT level, exhibited high diagnostic performance to predict NASH. Although validation in larger populations is needed, this result may be of considerable clinical value to predict need for liver biopsy.

Optimization of RNA extraction methods from human metabolic tissue samples of the COMET biobank.

Constitution of biobank of human tissues requires careful handling and storage of biological material, to guarantee the quality of samples. Tissue preparation is also critical for further applications such as transcriptomic profiling. In this study, our aim was to evaluate the impact of different disruption techniques (FastPrep-24 instrument, GentleMACS dissociator, and syringe/needle) and homogenizing buffers (RLT versus QIAzol) on RNA purity and quality of metabolic tissues (adipose tissues, liver and skeletal muscle) present in the COMET Biobank. For all homogenization methods used and tissue types, the A260/280 ratios reached values ≥ 1.8, which are in the range of what is found in human tissues and cell lines, while the A260/230 ratios were however ≤ 1.8, with the lowest value obtained with GentleMACS Dissociator. In addition, GentleMACS Dissociator combined with QIAzol reagent gave the highest RIN value and 28S/18S ratio for all tissues tested, except for muscle. Performing RT-qPCR, Ct values for different housekeeping genes can be influenced by extraction methods and RNA quality of samples. In conclusion, we have demonstrated that different disruption techniques and homogenizing buffers impact the purity and some quality markers of RNA, and can also impact quantification of mRNAs by RT-qPCR in human metabolic tissues.

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.

Differential sensitivity of human islets from obese versus lean donors to chronic high glucose or palmitate.

BACKGROUND: Due to the shortage of multi-organ donors, human pancreatic islet transplantation has now been extended to islets originating from obese subjects. In this study, our aim is to compare the respective sensitivity of human islets from lean vs obese donors to chronic high glucose or high palmitate. METHODS: Human islets were isolated from pancreases harvested from brain-dead multi-organ donors. Islets were cultured during 72 hours in the presence of moderate (16.7 mmol/L) or high (28 mmoL/L) glucose concentrations, or glucose (5.6 mmoL/L) and palmitate (0.4 mmoL/L), before measurement of their response to glucose. RESULTS: We first observed a greater insulin response in islets from obese donors under both basal and high-glucose conditions, confirming their hyperresponsiveness to glucose. When islets from obese donors were cultured in the presence of moderate or high glucose concentrations, insulin response to glucose remained unchanged or was slightly reduced, as opposed to that observed in lean subjects. Moreover, culturing islets from obese donors with high palmitate also induced less reduction in insulin response to glucose than in lean subjects. This partial protection of obese islets is associated with less induction of inducible nitric oxide synthase in islets, together with a greater expression of the transcription factor forkhead box O1 (FOXO1). CONCLUSIONS: Our data suggest that in addition to an increased sensitivity to glucose, islets from obese subjects can be considered as more resistant to glucose and fatty acid excursions and are thus valuable candidates for transplantation.

Solid-Phase Synthesis of Substrate-Based Dipeptides and Heterocyclic Pseudo-dipeptides as Potential NO Synthase Inhibitors.

More than 160 arginine analogues modified on the C-terminus via either an amide bond or a heterocyclic moiety (1,2,4-oxadiazole, 1,3,4-oxadiazole and 1,2,4-triazole) were prepared as potential inhibitors of NO synthases (NOS). A methodology involving formation of a thiocitrulline intermediate linked through its side-chain on a solid support followed by modification of its carboxylate group was developed. Finally, the side-chain thiourea group was either let unchanged, S-alkylated (Me, Et) or guanidinylated (Me, Et) to yield respectively after TFA treatment the corresponding thiocitrulline, S-Me/Et-isothiocitrulline and N-Me/Et-arginine substrate analogues. They all were tested against three recombinant NOS isoforms. Several compounds containing a S-Et- or a S-Me-Itc moiety and mainly belonging to both the dipeptide-like and 1,2,4-oxadiazole series were shown to inhibit nNOS and iNOS with IC50 in the 1-50 µM range. Spectral studies confirmed that these new compounds interacted at the heme active site. The more active compounds were found to inhibit intra-cellular iNOS expressed in RAW264.7 and INS-1 cells with similar efficiency than the reference compounds L-NIL and SEIT.

Zika virus induces strong inflammatory responses and impairs homeostasis and function of the human retinal pigment epithelium.

BACKGROUND: Zika virus (ZIKV) has recently re-emerged as a pathogenic agent with epidemic capacities as was well illustrated in South America. Because of the extent of this health crisis, a number of more serious symptoms have become associated with ZIKV infection than what was initially described. In particular, neuronal and ocular disorders have been characterized, both in infants and in adults. Notably, the macula and the retina can be strongly affected by ZIKV, possibly by a direct effect of the virus. This is supported by the detection of replicative and infectious virus in lachrimal fluid in human patients and mouse models. METHODS: Here, we used an innovative, state-of-the-art iPSC-derived human retinal pigment epithelium (RPE) model to study ZIKV retinal impairment. FINDINGS: We showed that the human RPE is highly susceptible to ZIKV infection and that a ZIKV African strain was more virulent and led to a more potent epithelium disruption and stronger anti-viral response than an Asian strain, suggesting lineage differences. Moreover, ZIKV infection led to impaired membrane dynamics involved in endocytosis, organelle biogenesis and potentially secretion, key mechanisms of RPE homeostasis and function. INTERPRETATION: Taken together, our results suggest that ZIKV has a highly efficient ocular tropism, which creates a strong inflammatory environment that could have acute or chronic adverse effects. FUND: This work was funded by Retina France, REACTing and La Région Languedoc-Roussillon.

Alzheimer's Disease: Advances in Drug Development.

As of 2018, Alzheimer's disease (AD) is the most common form of neurodegenerative dementia. It contributes to a progressive neuron loss, deterioration of memory, and cognitive impairment. Current therapies may provide a symptomatic benefit, but do not treat the underlying process. Ongoing researches focus on understanding the causal mechanisms and finding neuropathological hallmarks of AD. Therapeutic approaches targeting senile plaques or neurofibrillary tangles have not yet resulted in a significant cognitive improvement. However, recent data according to the analysis of AD clinical trials (clinicaltrials.gov database) show promising results. This literature review aims at summarizing the recent advances and at highlighting the most promising results of the ongoing researches. It compares the merits of small-molecules, antibodies, cell, and gene-based therapies and emphasizes the need for treatment at earlier stages of the disease.

Adipose tissue derived-factors impaired pancreatic ß-cell function in diabetes.

Inflammatory factors produced and secreted by adipose tissue, in particular peri-pancreatic adipose tissue (P-WAT), may influence pancreatic ß-cell dysfunction. Using the ZDF Rat model of diabetes, we show the presence of infiltrating macrophage (ED1 staining) on pancreatic tissue and P-WAT in the pre-diabetes stage of the disease. Then, when the T2D is installed, infiltrating cells decreased. Meanwhile, the P-WAT conditioned-medium composition, in terms of inflammatory factors, varies during the onset of the T2D. Using chemiarray technology, we observed an over expression of CXCL-1, -2, -3, CCL-3/MIP-1α and CXCL-5/LIX and TIMP-1 in the 9 weeks old obese ZDF pre-diabetic rat model. Surprisingly, the expression profile of these factors decreased when animals become diabetic (12 weeks obese ZDF rats). The expression of these inflammatory proteins is highly associated with inflammatory infiltrate. P-WAT conditioned-medium from pre-diabetes rats stimulates insulin secretion, cellular proliferation and apoptosis of INS-1 cells. However, inhibition of conditioned-medium chemokines acting via CXCR2 receptor do not change cellular proliferation apoptosis and insulin secretion of INS-1 cells induced by P-WAT conditioned-medium. Taken together, these results show that among the secreted chemokines, increased expression of CXCL-1, -2, -3 and CXCL-5/LIX in P-WAT conditioned-medium is concomitant with the onset of the T2D but do not exerted a direct effect on pancreatic ß-cell dysfunction.

5-HT2C receptors in the ventral tegmental area, but not in the arcuate nucleus, mediate the hypophagic and hypolocomotor effects of the selective 5-HT2C receptor agonist AR231630 in rats.

Central serotonin systems have long been associated with the control of feeding behavior and the modulation of behavioral effects of psychostimulants. 5-HT2C receptors are present in hypothalamic centers such as the arcuate nucleus (ARC), controlling homeostatic regulation of food intake, as well as in the ventral tegmental area (VTA), a region involved in motivation aspects in multiple behaviors, including feeding. In the present study, we investigated whether the 5-HT2C receptors control amphetamine-evoked locomotor activity and regulate food consumption. Localized microinjections into the VTA or the ARC were used to assess the effects of a highly selective 5-HT2C receptor agonist, AR231630, on the locomotor stimulant effect of amphetamine as well as on food intake. AR231630 injected into the VTA, but not into the ARC, dose-dependently reduced locomotor activity elicited by amphetamine. Unexpectedly, intra-ARC injection of AR231630 did not reduce food intake even at the dose of 10 µg, whereas intra-VTA injection of the same dose of AR231630 did. In addition, we showed that pretreatment with the selective 5-HT2C receptor antagonist SB242084 infused into the VTA partially prevented hypophagia induced by peripheral administration of AR231630. We can conclude that 5-HT2C receptor in the VTA, but not in the ARC, participates in both homeostatic and hedonic food intake and brain reward function.

Increase in insulin sensitivity by the association of chicoric acid and chlorogenic acid contained in a natural chicoric acid extract (NCRAE) of chicory (Cichorium intybus L.) for an antidiabetic effect.

ETHNOPHARMACOLOGICAL RELEVANCE: Chicory (Cichorium intybus L.) is an indigenous vegetable widely cultivated in Europe, America and Asia. In ancient times, the leaves, flowers, seeds, and roots have been used as a wealth of health benefits including its tonic effects, the ability to ease digestive problems and to detoxify liver. In Indian traditional therapy, chicory was known to possess antidiabetic effect. In the traditional medicine of Bulgaria and Italy, chicory was used as hypoglycemic decoctions. AIMS OF THE STUDIES: We wanted to obtain the complete chemical composition of the natural chicoric acid extract (NCRAE), a chicory root extract rich in chicoric acid, which previously showed its glucose tolerance effect in normal rats. To investigate if the whole NCRAE is required to be effective, we performed a comparative in vivo experiment on STZ diabetic rats treated either with NCRAE or a mixture composed of the two major compounds of NCRAE. MATERIALS AND METHODS: LC-MS method has been used to analyze the exhaustive composition of NCRAE: we have determined that chicoric acid and chlorogenic acid represented 83.8% of NCRAE. So, we have prepared a solution mixture of chicoric acid and chlorogenic acid named SCCAM, in order to compare in vivo the antidiabetic effects of this last and NCRAE in streptozotocin diabetic rats. In vitro experiments were performed on L6 cell line both for glucose uptake and for the protective effect against H2O2 oxidative stress. Also, we have evaluated DPPH and ORAC (Oxygen Radical Absorbance Capacity) antioxidative capacities of the two compositions. RESULTS: The LC-MS analysis confirmed the high abundance of chicoric acid (64.2%) in NCRAE and a second part of NCRAE is composed of caffeoylquinic acids (CQAs) at 19.6% with among them the chlorogenic acid. This result has permitted us to prepare a mixture of synthetic L-chicoric acid (70%) and synthetic chlorogenic acid (30%): the solution is designated SCCAM. Our results showed that both NCRAE and SCCAM are able to improve a glucose tolerance in STZ diabetic rats after a subchronic administration of seven days. Alone NCRAE allows to significantly decrease the basal hyperglycemia after six days of treatment. To explain these difference of effects between NCRAE and SCCAM, we have compared their in vitro effects on the L6 muscle cell line both for the insulin sensitizing effect and for their protective action in pretreatment against H2O2. We have also compared their antioxidant capacities. In conclusion, we demonstrated that NCRAE, a natural extract of chicory (Cichorium intybus) rich in CRA and CQAs improves glucose tolerance and reduces the basal hyperglycemia in STZ diabetic rats.

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.

Relaxin and atrial natriuretic peptide pathways participate in the anti-fibrotic effect of a melon concentrate in spontaneously hypertensive rats.

BACKGROUND: In spontaneously hypertensive rats (SHR), a model of human essential hypertension, oxidative stress is involved in the development of cardiac hypertrophy and fibrosis associated with hypertension. Dietary supplementation with agents exhibiting antioxidant properties could have a beneficial effect in remodeling of the heart. We previously demonstrated a potent anti-hypertrophic effect of a specific melon (Cucumis melo L.) concentrate with antioxidant properties in spontaneously hypertensive rats. Relaxin and atrial natriuretic peptide (ANP) were reported to reduce collagen deposition and fibrosis progression in various experimental models. OBJECTIVE: The aim of the present investigation was to test the hypothesis that, beside reduction in oxidative stress, the melon concentrate may act through relaxin, its receptor (relaxin/insulin-like family peptide receptor 1, RXFP1), and ANP in SHR. DESIGN AND RESULTS: The melon concentrate, given orally during 4 days, reduced cardiomyocyte size (by 25%) and totally reversed cardiac collagen content (Sirius red staining) in SHR but not in their normotensive controls. Treatment with the melon concentrate lowered cardiac nitrotyrosine-stained area (by 45%) and increased by 17-19% the cardiac expression (Western blot) of superoxide dismutase (SOD) and glutathione peroxidase. In addition, plasma relaxin concentration was normalized while cardiac relaxin (Western blot) was lowered in treated SHR. Cardiac relaxin receptor level determined by immunohistochemical analysis increased only in treated SHR. Similarly, the melon concentrate reversed the reduction of plasma ANP concentration and lowered its cardiac expression. CONCLUSIONS: The present results demonstrate that reversal of cardiac fibrosis by the melon concentrate involves antioxidant defenses, as well as relaxin and ANP pathways restoration. It is suggested that dietary SOD supplementation could be a useful additional strategy against cardiac hypertrophy and fibrosis.

Possible protective effect of membrane lipid rafts against interleukin-1ß-mediated anti-proliferative effect in INS-1 cells.

We recently reported that pancreatic islets from pre-diabetic rats undergo an inflammatory process in which IL-1ß takes part and controls ß-cell function. In the present study, using the INS-1 rat pancreatic ß-cell line, we investigated the potential involvement of membrane-associated cholesterol-enriched lipid rafts in IL-1ß signaling and biological effects on insulin secretion, ß-cell proliferation and apoptosis. We show that, INS-1 cells exposure to increasing concentrations of IL-1ß leads to a progressive inhibition of insulin release, an increase in the number of apoptotic cells and a dose-dependent decrease in pancreatic ß-cell proliferation. Disruption of membrane lipid rafts markedly reduced glucose-stimulated insulin secretion but did not affect either cell apoptosis or proliferation rate, demonstrating that membrane lipid raft integrity is essential for ß-cell secretory function. In the same conditions, IL-1ß treatment of INS-1 cells led to a slight further decrease in insulin secretion for low concentrations of the cytokine, and a more marked one, similar to that observed in normal cells for higher concentrations. These effects occurred together with an increase in iNOS expression and surprisingly with an upregulation of tryptophane hydroxylase and protein Kinase C in membrane lipid rafts suggesting that compensatory mechanisms develop to counteract IL-1ß inhibitory effects. We also demonstrate that disruption of membrane lipid rafts did not prevent cytokine-induced cell death recorded after exposure to high IL-1ß concentrations. Finally, concerning cell proliferation, we bring strong evidence that membrane lipid rafts exert a protective effect against IL-1ß anti-proliferative effect, possibly mediated at least partly by modifications in ERK and PKB expression/activities. Our results 1) demonstrate that IL-1ß deleterious effects do not require a cholesterol-dependent plasma membrane compartmentalization of IL-1R1 signaling and 2) confer to membrane lipid rafts integrity a possible protective function that deserves to be considered in the context of inflammation and especially T2D pathogenesis.