Chronic intermittent hypoxia due to obstructive sleep apnea slightly alters nutritional status: a pre-clinical study.

Obstructive sleep apnea syndrome (OSAS) is associated with chronic intermittent hypoxia (cIH) that causes disturbances in glucose and lipid metabolism. Animals exposed to cIH show lower body weight and food intake, but the protein-energy metabolism has never been investigated. Here, to address the gap, we studied the impact of cIH on nutritional status in rats.

Protein intake in cancer: Does it improve nutritional status and/or modify tumour response to chemotherapy?

Background: Combating malnutrition and cachexia is a core challenge in oncology. To limit muscle mass loss, the use of proteins in cancer is encouraged by experts in the field, but it is still debated due to their antagonist effects. Indeed, a high protein intake could preserve lean body mass but may promote tumour growth, whereas a low-protein diet could reduce tumour size but without addressing cachexia.

Regulation of citrulline synthesis in human enterocytes: Role of hypoxia and inflammation.

Intensive care unit patients and chronic airway inflammatory disease are characterized by chronic systemic hypoxia and inflammation inducing a decrease in nitric oxide release due to impaired l-arginine (ARG) homeostasis. As ARG is synthesized from circulating l-citrulline (CIT), an alteration of CIT production in small intestine by ornithine carbamoyltransferase could be involved. Here, we posit that hypoxia and/or inflammation has effects on ornithine carbamoyltransferase regulation in enterocytes.

Ornithine Transcarbamylase - From Structure to Metabolism: An Update.

Ornithine transcarbamylase (OTC; EC 2.1.3.

Dietary citrulline does not modify rat colon tumor response to chemotherapy, but failed to improve nutritional status.

During cancer therapy many patients experience significant malnutrition, leading to decreased tolerance to chemotherapy and decreased survival. Dietary citrulline supplementation improves nutritional status in situations such as short bowel syndrome and aging, and is of potential interest in oncology. However, a mandatory prerequisite is to test this amino acid for interaction with tumor growth and chemotherapy response.

Modulation of muscle protein synthesis by amino acids: what consequences for the secretome? A preliminary in vitro study.

The modulation by amino acids of muscle secretome is largely unknown. In this study, we investigate the effect of hyperaminoacidemia or specific amino acids (citrulline or leucine) on protein synthesis and secretome in myotubes. All conditions stimulate muscle protein synthesis, and secretome is differently modulated depending of the amino acids considered.

Nitric oxide production by peritoneal macrophages from aged rats: A short term and direct modulation by citrulline.

Citrulline has anti-inflammatory properties and exerts beneficial effects on various impaired functions in aging. However, there are few data on citrulline action on immune function in aged populations. The objective of the study was to evaluate citrulline ability, after in vivo and in vitro administration, to modulate macrophage functions in aged rats and the possible pathways involved.

Short-term Effects of Diet and Activity Changes on Inflammation and Insulin Resistance.

The present study focused on rapid responses of inflammation markers and insulin resistance to dietary restriction and exercise in inactive patients. 13 obese women were included during a 5-day time frame during which decreases in food intake (-1 378±298 kcal) were associated with 2 exercise sessions (80 and 40 min). Circulating inflammatory biomarkers, insulin resistance index and muscle soreness were measured in fasted conditions.

Citrulline and nitrogen homeostasis: an overview.

Citrulline (Cit) is a non-essential amino acid whose metabolic properties were largely ignored until the last decade when it began to emerge as a highly promising nutrient with many regulatory properties, with a key role in nitrogen homeostasis. Because Cit is not taken up by the liver, its synthesis from arginine, glutamine, ornithine and proline in the intestine prevents the hepatic uptake of the two first amino acids which activate the urea cycle and so prevents amino acid catabolism. This sparing effect may have positive spin-off for muscle via increased protein synthesis, protein content and functionality.

In vitro anti-inflammatory effects of citrulline on peritoneal macrophages in Zucker diabetic fatty rats.

In type 2 diabetes (T2D) macrophage dysfunction increases susceptibility to infection and mortality. This may result from the associated decreased plasma concentration of arginine, an amino acid that plays an important role in immunity. In vitro, increasing arginine availability leads to an improvement in macrophage function; however, arginine supplementation in diabetic obese patients may be detrimental.

Effects of a diabetes-specific enteral nutrition on nutritional and immune status of diabetic, obese, and endotoxemic rats: interest of a graded arginine supply.

Objective: Obese and type 2 diabetic patients present metabolic disturbance-related alterations in nonspecific immunity, to which the decrease in their plasma arginine contributes. Although diabetes-specific formulas have been developed, they have never been tested in the context of an acute infectious situation as can be seen in intensive care unit patients. Our aim was to investigate the effects of a diabetes-specific diet enriched or not with arginine in a model of infectious stress in a diabetes and obesity situation.

Arginine availability modulates arginine metabolism and TNFα production in peritoneal macrophages from Zucker Diabetic Fatty rats.

Background & Aims: Excess weight and type 2 diabetes lead to increased susceptibility to infections. Our aim was to investigate the role of diabetes-induced decreased arginine (Arg) availability and of a possible dysregulation of Arg metabolism in macrophages favoring inflammation and dysimmunity via altered nitric oxide (NO) and cytokine productions.

Methods: Isolated peritoneal macrophages from Zucker Diabetic Fatty (ZDF) or lean rats were incubated with increasing Arg concentration (0-2 mM) and Arg metabolism and regulatory properties were studied.

High plasma citrulline and arginine levels ensured by sustained-release citrulline supplementation in rats.

Objective: Dietary-supplemented arginine has been shown to have positive effects on cardiovascular disease, but several drawbacks exist and could potentially be avoided by using L-citrulline, since it is recycled to L-arginine. However, citrulline is very rapidly metabolized. We therefore developed a sustained-release form of citrulline and evaluated its metabolic behavior in rats.