Increasing plant protein in the diet induces changes in the plasma metabolome that may be beneficial for metabolic health. A randomized crossover study in males.

Background & Aim: Dietary shifts replacing animal protein (AP) with plant protein (PP) sources have been associated with lowering cardiometabolic risk (CMR), but underlying mechanisms are poorly characterized. This nutritional intervention aims to characterize the metabolic changes induced by diets containing different proportions of AP and PP sources in males at CMR.

Design: This study is a 4-week, crossover, randomized, controlled-feeding trial in which 19 males with CMR followed two diets providing either 36 % for the control diet (CON-D) or 64 % for the flexitarian diet (FLEX-D) of total protein intake from PP sources.

Compared with Milk Protein, a Wheat and Pea Protein Blend Reduces High-Fat, High-Sucrose Induced Metabolic Dysregulations while Similarly Supporting Tissue Protein Anabolism in Rats.

Background: Plant proteins (PPs) have been associated with better cardiovascular health than animal proteins (APs) in epidemiological studies. However, the underlying metabolic mechanisms remain mostly unknown.

Objectives: Using a combination of cutting-edge isotopic methods, we aimed to better characterize the differences in protein and energy metabolisms induced by dietary protein sources (PP compared with AP) in a prudent or western dietary context.

Plant Protein Can Be as Efficient as Milk Protein to Maintain Fat Free Mass in Old Rats, Even When Fat and Sugar Intakes Are High.

Background: Alternative, sustainable, and adequate sources of protein must be found to meet global demand.

Objectives: Our aim was to assess the effect of a plant protein blend with a good balance of indispensable amino acids and high contents of leucine, arginine, and cysteine on the maintenance of muscle protein mass and function during aging in comparison to milk proteins and to determine if this effect varied according to the quality of the background diet.

Methods: Old male Wistar rats (n = 96, 18 mo old) were randomly allocated for 4 mo to 1 of 4 diets, differing according to protein source (milk or plant protein blend) and energy content (standard, 3.

Anti-inflammatory CNRZ160 limits sarcopenia induced by low-grade inflammation in older adult rats.

Background And Aims: Aging is characterized, at the systemic level, by the development of low-grade inflammation, which has been identified as determining sarcopenia by blunting postprandial muscle anabolism. The causes of this "inflammageing" is still not clearly defined. An increased intestinal permeability, a microbiota dysbiosis and subsequent generation of intestinal then generalized inflammation have been hypothesized.

Weaning and stunting affect nitrogen and carbon stable isotope natural abundances in the hair of young children.

Natural abundances of stable nitrogen and carbon isotopes (δN and δC) can vary with both dietary intake and metabolic (specifically catabolic) state. In low-income countries, weaning is a period of dietary transition from milk to plant-based foods and a high-risk period for malnutrition. We explored how diet and malnutrition impact hair δN and δC in young children by an observational, cross-sectional study in Cox's Bazar District, Bangladesh [255 children, 6-59 months with 19.

Intestinal Availability and Metabolic Effects of Dietary Sphingolipids during the Metabolic Syndrome Onset in Mice.

Sphingolipids appear as a promising class of components susceptible to prevent the onset of the metabolic syndrome (MetS). Gut availability and effects of sphingolipids were investigated in a mouse model of dietary-induced MetS. Seed meals from two lines enriched, respectively, in C24- and C16-NH glycosyl-inositol-phosphoryl-ceramides (NHGIPC) were used in hypercaloric diets.

Natural Isotope Abundances of Carbon and Nitrogen in Tissue Proteins and Amino Acids as Biomarkers of the Decreased Carbohydrate Oxidation and Increased Amino Acid Oxidation Induced by Caloric Restriction under a Maintained Protein Intake in Obese Rats.

A growing body of evidence supports a role for tissue-to-diet N and C discrimination factors (ΔN and ΔC), as biomarkers of metabolic adaptations to nutritional stress, but the underlying mechanisms remain poorly understood. In obese rats fed ad libitum or subjected to gradual caloric restriction (CR), under a maintained protein intake, we measured ΔN and ΔC levels in tissue proteins and their constitutive amino acids (AA) and the expression of enzymes involved in the AA metabolism. CR was found to lower protein mass in the intestine, liver, heart and, to a lesser extent, some skeletal muscles.

Postprandial low-grade inflammation does not specifically require TLR4 activation in the rat.

Background: Toll-like receptor 4 (TLR4), an innate immune receptor, is suspected to play a key role in the postprandial inflammation that is induced by a high-fat meal rich in saturated fatty acids (SFA). Our objective was to test this hypothesis by using a specific competitive inhibitor of TLR4 (INH) vs vehicle (VEH) administered immediately before a high-SFA meal in rats.

Methods: First, in a cross-over kinetic study of 12 rats receiving INH and VEH 10 min before the test meal, we measured plasma inflammatory and vascular markers for 6 h.

n-3 Fatty acids preserve muscle mass and insulin sensitivity in a rat model of energy restriction.

In obese subjects, the loss of fat mass during energy restriction is often accompanied by a loss of muscle mass. The hypothesis that n-3 PUFA, which modulate protein homoeostasis via effects on insulin sensitivity, could contribute to maintain muscle mass during energy restriction was tested in rats fed a high-fat diet (4 weeks) rich in 18 : 1 n-9 (oleic acid, OLE-R), 18 : 3 n-3 (α-linolenic acid, ALA-R) or n-3 long-chain (LC-R) fatty acid and then energy restricted (8 weeks). A control group (OLE-ad libitum (AL)) was maintained with AL diet throughout the study.

l-Arginine Supplementation Alleviates Postprandial Endothelial Dysfunction When Baseline Fasting Plasma Arginine Concentration Is Low: A Randomized Controlled Trial in Healthy Overweight Adults with Cardiometabolic Risk Factors.

Background: Vascular endothelial dysfunction, the hallmark of early atherosclerosis, is induced transiently by a high-fat meal. High doses of free l-arginine supplements reduce fasting endothelial dysfunction.

Objective: We sought to determine the effects of a low dose of a sustained-release (SR) l-arginine supplement on postprandial endothelial function in healthy overweight adults with cardiometabolic risk factors and to investigate whether this effect may vary by baseline arginine status.

A Slow- Compared with a Fast-Release Form of Oral Arginine Increases Its Utilization for Nitric Oxide Synthesis in Overweight Adults with Cardiometabolic Risk Factors in a Randomized Controlled Study.

Background: Oral l-arginine supplements can have a beneficial effect on nitric oxide (NO)-related functions when subjects have cardiovascular disease risk factors.

Objective: The study was designed to determine the utilization for NO synthesis of oral l-arginine as a function of the cardiometabolic risk and the speed of absorption by comparing immediate-release arginine (IR-Arg), as in supplements, and sustained-release arginine (SR-Arg), which mimics the slow release of dietary arginine.

Methods: In a randomized, single-blind, 2-period crossover, controlled trial (1 wk of treatment, >2 wk of washout), using [(15)N-(15)N-(guanidino)]-arginine for the first morning dose, we compared the bioavailability (secondary outcome) and utilization for NO synthesis (primary outcome) of 1.

NO synthesis from arginine is favored by α-linolenic acid in mice fed a high-fat diet.

Alterations in NO availability and signaling play a pivotal role at early stages of the metabolic syndrome (MetSynd). We hypothesized that dietary α-linolenic acid (ALA, 18:3 n-3) favors NO availability by modulating amino acid metabolism, with a specific impact on the arginine-NO pathway. Mice were fed a hyperlipidic diet (285 g lipid/kg, 51.

Casein Compared with Whey Proteins Affects the Organization of Dietary Fat during Digestion and Attenuates the Postprandial Triglyceride Response to a Mixed High-Fat Meal in Healthy, Overweight Men.

Background: Postprandial lipemia is a risk factor for cardiovascular disease. The potential impacts of the type/nature of dietary protein on postprandial lipemia and associated dysregulations have been insufficiently investigated.

Objective: We investigated the postprandial effect of including in a high-fat meal some milk protein fractions that markedly differ in their physicochemical properties and composition [either casein (CAS), whey protein (WHE), or α-lactalbumin-enriched whey protein (LAC)].

Plasma asymmetric and symmetric dimethylarginine in a rat model of endothelial dysfunction induced by acute hyperhomocysteinemia.

Hyperhomocysteinemia induces vascular endothelial dysfunction, an early hallmark of atherogenesis. While higher levels of circulating asymmetric dimethylarginine (ADMA) and symmetric dimethyl arginine (SDMA), endogenous inhibitors of nitric oxide synthesis, have been associated with increased cardiovascular risk, the role that ADMA and SDMA play in the initiation of hyperhomocysteinemia-induced endothelial dysfunction remains still controversial. In the present study, we studied the changes of circulating ADMA and SDMA in a rat model of acutely hyperhomocysteinemia-induced endothelial dysfunction.

Consequences of PPAR(α) Invalidation on Glutathione Synthesis: Interactions with Dietary Fatty Acids.

Glutathione (GSH) derives from cysteine and plays a key role in redox status. GSH synthesis is determined mainly by cysteine availability and γ-glutamate cysteine ligase (γGCL) activity. Because PPARα activation is known to control the metabolism of certain amino acids, GSH synthesis from cysteine and related metabolisms were explored in wild-type (WT) and PPARα-null (KO) mice, fed diets containing either saturated (COCO diet) or 18 : 3 n-3, LIN diet.

Quinoa extract enriched in 20-hydroxyecdysone protects mice from diet-induced obesity and modulates adipokines expression.

Besides their well-known effect in the molting control in insects, ecdysteroids are steroid hormones that display potential pharmacologic and metabolic properties in mammals. The most common ecdysteroid, 20-hydroxyecdysone (20E) is found in many plants such as quinoa. The aim of the present study was to investigate the ability of quinoa extract (Q) enriched in 20E supplementation to prevent the onset of diet-induced obesity and to regulate the expression of adipocyte-specific genes in mice.

Olanzapine-induced accumulation of adipose tissue is associated with an inflammatory state.

Second-generation antipsychotics are widely used in the treatment of all forms of psychoses, but they often produce undesirable side effects, among which are weight gain and other elements of metabolic syndrome. The mechanisms of these adverse effects are not known. The liver and adipose tissue are the principal candidate organs implicated in the development of antipsychotic-induced metabolic adverse effects.

Early postprandial low-grade inflammation after high-fat meal in healthy rats: possible involvement of visceral adipose tissue.

In the postprandial period, low-grade inflammation may contribute to vascular endothelial dysfunction, a hallmark of atherogenesis. Little is known about the involvement of the adipose tissue in the initiation of the postprandial inflammatory response such as obtained after a high-saturated fat meal (HFM). In the present study, we first studied the time course of appearance of systemic inflammation after a HFM in healthy rats, and then we investigated whether a HFM activates the inflammatory signaling in the visceral adipose tissue, with a focus on the key component, nuclear factor-kappaB (NF-kappaB).

Nitric oxide bioavailability and not production is first altered during the onset of insulin resistance in sucrose-fed rats.

Although the role of nitric oxide (NO) in peripheral glucose uptake has been thoroughly described, little is known regarding the alterations in NO metabolism during the early onset of insulin resistance. During this study we investigated the alterations in NO synthesis and bioavailability in a model for dietary modulations of insulin sensitivity. For 6 weeks, rats were fed a standard diet (C), a high-sucrose diet inducing insulin resistance (HS), or high-sucrose diets supplemented with cysteine, which endowed protection against the high-sucrose-induced insulin resistance (Ti).

Dietary cysteine alleviates sucrose-induced oxidative stress and insulin resistance.

Diets that promote oxidative stress favor impairment in glucose homeostasis. In this context, increasing the cysteine intake may be beneficial by maintaining glutathione status. We have investigated the effects of dietary cysteine on oxidative stress and glucose homeostasis in rats fed a high-sucrose (HS) diet.

Liver glyconeogenesis: a pathway to cope with postprandial amino acid excess in high-protein fed rats?

This paper provides molecular evidence for a liver glyconeogenic pathway, that is, a concomitant activation of hepatic gluconeogenesis and glycogenesis, which could participate in the mechanisms that cope with amino acid excess in high-protein (HP) fed rats. This evidence is based on the concomitant upregulation of phosphoenolpyruvate carboxykinase (PEPCK) gene expression, downregulation of glucose 6-phosphatase catalytic subunit (G6PC1) gene expression, an absence of glucose release from isolated hepatocytes and restored hepatic glycogen stores in the fed state in HP fed rats. These effects are mainly due to the ability of high physiological concentrations of portal blood amino acids to counteract glucagon-induced liver G6PC1 but not PEPCK gene expression.

The reduced energy intake of rats fed a high-protein low-carbohydrate diet explains the lower fat deposition, but macronutrient substitution accounts for the improved glycemic control.

The metabolic effect of high-protein low-carbohydrate (HP) diets on body composition and glucose homeostasis remains incompletely understood. This study assesses the respective roles of the increased protein:carbohydrate ratio (P:C) and the resulting moderate decrease in energy intake in the metabolic effects of HP diets. Rats had free access to normal (NP; 14%) or high (HP; 53%) total milk protein isoenergetic diets, or were fed the NP diet but restricted to the energy intake of HP rats (NPr), which was 89.

A long-term high-protein diet markedly reduces adipose tissue without major side effects in Wistar male rats.

Although there is a considerable interest of high-protein, low-carbohydrate diets to manage weight control, their safety is still the subject of considerable debate. They are suspected to be detrimental to the renal and hepatic functions, calcium balance, and insulin sensitivity. However, the long-term effects of a high-protein diet on a broad range of parameters have not been investigated.