Citrulline protects human retinal pigment epithelium from hydrogen peroxide and iron/ascorbate induced damages.

Oxidative stress plays an important role in the ageing of the retina and in the pathogenesis of retinal diseases such as age-related macular degeneration (ARMD). Hydrogen peroxide is a reactive oxygen species generated by the photo-excited lipofuscin that accumulates during ageing in the retinal pigment epithelium (RPE), and the age-related accumulation of lipofuscin is associated with ARMD. Iron also accumulates with age in the RPE that may contribute to ARMD as an important source of oxidative stress.

Glutamate: A Safe Nutrient, Not Just a Simple Additive.

Background: In 2017, a European Food Safety Authority (EFSA) opinion on the use of glutamate and its salts as food additives led to an Acceptable Daily Intake (ADI) of 30 mg/kg body weight/day. Then, in 2021, an EFSA statement presented a proposal for harmonizing the establishment of Health-Based Guidance Values for nutrients that are also regulated substances (including food additives). The present review argues that the 2017 glutamate ADI is unsuitable because safety of glutamate should firstly consider its status as a nutrient and not only as an additive.

Is -Carbamoyl Putrescine, the Decarboxylation Derivative of Citrulline, a Regulator of Muscle Protein Metabolism in Rats?

-carbamoyl putrescine (NCP), the decarboxylation derivative of citrulline, metabolically related to polyamines, may exert biological effects in mammals. The aim of this study was (i) to evaluate the nutritional properties of NCP in healthy rats and (ii) to determine the effect of NCP administration on muscle metabolism in malnourished old rats. The nutritional properties of NCP were first evaluated in 20 8-week-old male rats randomized to receive for two weeks a standard diet either alone (C group) or supplemented with NCP, 5 or 50 mg/kg/d.

An oligomeric diet limits the response to injury in traumatic brain-injured rats.

Adequate nutritional support is a major challenge in brain injury patients, because malnutrition cannot be reversed by standard enteral nutrition. We hypothesized that an oligomeric formula could improve nutritional status by restoring intestinal trophicity. Eighteen male Sprague-Dawley rats (300-330 g) underwent gastrostomy on day-7 (D-7) and traumatic brain injury (TBI) by hydraulic percussion (D0) and were then fed for 4 days with either a polymeric formula (Sondalis® HP, TBIP, n = 9), or an oligomeric formula (Peptamen® HN, TBIO, n = 9).

Increasing plasma glutamine in postoperative patients fed an arginine-rich immune-enhancing diet--a pharmacokinetic randomized controlled study.

Objective: Immune-enhancing diets (IEDs) rich in arginine (ARG) reduce morbi-mortality in trauma and surgical patients. Among the pharmaconutrients inducing these effects, ARG may be involved by generating active metabolites such as glutamine (GLN). However, the ability of an ARG-enriched diet to normalize GLN plasma levels in intensive care unit (ICU) patients has never been documented.

Tolerance and efficacy of a new enteral formula specifically designed for elderly persons: an experimental study in the aged rat.

For the first time, a formula was specifically designed for the nutritional support of tube-fed elderly patients (Elderly-Specific Formula [ESF], Nestlé, Switzerland). It was tested against a standard formula (Sondalis Iso [SI], Nestlé Clinical Nutrition, Marne la Vallée, France) in sixteen 22-month-old Sprague Dawley rats fed by total continuous enteral infusion for 7 days. Body weight, stool weight, and nitrogen balance were measured daily.

Does the ornithine-alpha-ketoglutarate ratio influence ornithine alpha-ketoglutarate metabolism in healthy rats?

Ornithine alpha-ketoglutarate (OKG) is a salt composed of 2 molecules of ornithine (ORN) and one molecule of alpha-ketoglutarate (alphaKG). OKG has been used successfully via oral, enteral, and parenteral routes to improve protein status in patients with chronic and acute protein depletion, but its mechanism of action, which is probably multifactorial, is still unclear. A specific metabolic interaction between alphaKG and ORN has been shown to be a key factor in the effects of OKG, but the impact of the ORN/alphaKG ratio (2 molecules of ORN for 1 molecule of alphaKG) has never been discussed.

Evaluation of a glycine-rich amino acid solution for parenteral nutrition in endotoxemic rats.

Objective: It has been shown recently that high amounts of glycine might have some pharmacologic effects (reduction of injury and mortality in endotoxemic rats), but its effects on the nutritional status and protein metabolism during injury are still unknown. The aim of this study was to compare the nutritional effects of a glycine-rich amino acid solution for parenteral nutrition (AFD) with a standard one (Vintene) (glycine, 15 vs. 9 g/L) in endotoxemic rats.

Ornithine alpha-ketoglutarate metabolism in the healthy rat in the postabsorptive state.

To gain further insight into the ability of ornithine alpha-ketoglutarate (OKG) to generate key metabolites, the aim of this work was to study the short-term metabolism, that is, 1 hour after administration, of OKG in plasma and tissues. Particular attention was paid to keto acids (alpha-ketoglutarate and branched-chain keto acids). Young (3 weeks old) male Wistar rats in the postabsorptive state received either 1.