Noninvasive measurements of body composition and body water via quantitative magnetic resonance, deuterium water, and dual-energy x-ray absorptiometry in cats.

OBJECTIVE: To compare quantitative magnetic resonance (QMR), dual-energy x-ray absorptiometry (DXA), and deuterium oxide (D2O) dilution methods for measurement of total body water (TBW), lean body mass (LBM), and fat mass (FM) in healthy cats and to assess QMR precision and accuracy. ANIMALS: Domestic shorthair cats (58 and 32 cats for trials 1 and 2, respectively). PROCEDURES: QMR scans of awake cats performed with 2 units were followed by administration of D2O tracer (100 mg/kg, PO). Cats then were anesthetized, which was followed by QMR and DXA scans. Jugular blood samples were collected before and 120 minutes after D2O administration. RESULTS: QMR precision was similar between units (coefficient of variation < 2.9% for all measures). Fat mass, LBM, and TBW were similar for awake or sedated cats and differed by 4.0%, 3.4%, and 3.9%, respectively, depending on the unit. The QMR minimally underestimated TBW (1.4%) and LBM (4.4%) but significantly underestimated FM (29%), whereas DXA significantly underestimated LBM (9.2%) and quantitatively underestimated FM (9.3%). A significant relationship with D2O measurement was detected for all QMR (r(2) > 0.84) and DXA (r(2) > 0.84) measurements. CONCLUSIONS AND CLINICAL RELEVANCE: QMR was useful for determining body composition in cats; precision was improved over DXA. Quantitative magnetic resonance can be used to safely and rapidly acquire data without the need for anesthesia, facilitating frequent monitoring of weight changes in geriatric, extremely young, or ill pets. Compared with the D2O dilution method, QMR correction equations provided accurate data over a range of body compositions.

Noninvasive measurements of body composition and body water via quantitative magnetic resonance, deuterium water, and dual-energy x-ray absorptiometry in awake and sedated dogs.

OBJECTIVE: To compare quantitative magnetic resonance (QMR), dual-energy x-ray absorptiometry (DXA), and deuterium oxide (D2O) methods for measurement of total body water (TBW), lean body mass (LBM), and fat mass (FM) in healthy dogs and to assess QMR accuracy. ANIMALS: 58 Beagles (9 months to 11.5 years old). PROCEDURES: QMR scans were performed on awake dogs. A D2O tracer was administered (100 mg/kg, PO) immediately before dogs were sedated, which was followed by a second QMR or DXA scan. Jugular blood samples were collected before and 120 minutes after D2O administration. RESULTS: TBW, LBM, and FM determined via QMR were not significantly different between awake or sedated dogs, and means differed by only 2.0%, 2.2%, and 4.3%, respectively. Compared with results for D2O dilution, QMR significantly underestimated TBW (10.2%), LBM (13.4%), and FM (15.4%). Similarly, DXA underestimated LBM (7.3%) and FM (8.4%). A significant relationship was detected between FM measured via D2O dilution and QMR (r(2) > 0.89) or DXA (r(2) > 0.88). Even though means of TBW and LBM differed significantly between D2O dilution and QMR or DXA, values were highly related (r(2) > 0.92). CONCLUSIONS AND CLINICAL RELEVANCE: QMR was useful for determining body composition in dogs and can be used to safely and rapidly acquire accurate data without the need for sedation or anesthesia. These benefits can facilitate frequent scans, particularly in geriatric, extremely young, or ill pets. Compared with the D2O dilution method, QMR correction equations provided accurate assessment over a range of body compositions.

Lipid transport function is the main target of oral oleoylethanolamide to reduce adiposity in high-fat-fed mice.

We evaluated the biological basis of reduced fat gain by oleoylethanolamide (OEA) in high-fat-fed mice and sought to determine how degradation of OEA affected its efficiency by comparing its effects to those of KDS-5104, a nonhydrolyzable lipid OEA analog. Mice were given OEA or KDS-5104 by the oral route (100 mg/kg body weight). Sixty-eight variables per mouse, describing six biological processes (lipid transport, lipogenesis, energy intake, energy expenditure, endocannabinoid signaling, and glucose metabolism), spanning gene expression of biochemical and physiological parameters were examined to determine the primary target whereby OEA reduces fat gain. Although KDS-5104 but not OEA was resistant to fatty acid amide hydrolase hydrolysis, OEA was degraded by an unidentified hydrolysis system in the liver. Nevertheless, both compounds equally decreased body fat pads after 5 weeks (20%; P < 0.05). The six biological functions constructed from the 68 initial variables predicted up to 58% of adipose fat variations. Lipid transport appeared central to the explanation for body fat deposition (16%; P < 0.0001), in which decreased expression of the FAT/CD36 gene was the component most related to adipose depots. Lipid transport appears to be a determinant player in the OEA fat-lowering response, with adipose tissue FAT/CD36 expression being the most relevant bioindicator of OEA action.

Analysis of gene expression pattern reveals potential targets of dietary oleoylethanolamide in reducing body fat gain in C3H mice.

Oleoylethanolamide (OEA) has been previously reported to regulate food intake and body weight gain when administered intraperitoneally. Nevertheless, little information is available with regard to oral administration. To assess whether oral OEA can also exert a similar effect on body fat, we fed C3H mice a high-fat diet supplemented with either 10 or 100 mg/kg body weight OEA for 4 weeks. OEA supplementation significantly lowered food intake over the 4 weeks and decreased adipose tissue mass. Plasma triglyceride levels were also significantly decreased by OEA treatment. In order to identify the potential molecular targets of OEA action, we screened the expression levels of 44 genes related to body fat mass and food intake in peripheral tissues. Adipose tissue fatty acid amide hydrolase (FAAH), intestinal fatty acid transporter/cluster of differentiation 36 and the OEA receptor G-protein-coupled receptor 119 (GPR119) were among the most OEA-responsive genes. They were also associated with reduced body fat pads regardless of the dose. Adipose FAAH was found to be primarily associated with a decrease in food intake. Our data suggest that the anti-obesity activity of OEA partially relies on modulation of the FAAH pathway in adipose tissue. Another mechanism might involve modulation of the newly discovered GPR119 OEA signaling pathway in the proximal intestine. In conclusion, our study indicates that oral administration of OEA can effectively decrease obesity in the mouse model and that modulation of the endocannabinoid fatty acid ethanolamide pathway seems to play an important role both in adipose tissue and in small intestine.

Biological functions and metabolism of oleoylethanolamide.

The present review is focused on the metabolism and the emerging roles of oleoylethanolamide (OEA) with emphasis on its effects on food intake control and lipid metabolism. The biological mechanism of action, including a non-genomic effect mediated through peroxisome proliferator-activated receptor alpha (PPAR-alpha) and transient receptor potential vanilloid type 1 (TRPV1) receptor, is discussed. The research related to fatty acid ethanolamides has been focused until recently on anandamide and its interaction with cannabinoid receptor subtype 1. The roles of other N-acyl ethanolamine fatty acid derivatives have been neglected until it was demonstrated that OEA can modulate food intake control through interaction with PPAR-alpha. Further investigations demonstrated that OEA modulates lipid and glucose metabolism, and recent study confirmed that OEA is an antagonist of TRVP1. It has been demonstrated that OEA has beneficial effects on health by inducing food intake control, lipid beta-oxidation, body weight loss and analgesic effects. The investigation of the mechanism of action revealed that OEA activates PPAR-alpha and stimulates the vagal nerve through the capsaicin receptor TRPV1. Pre-clinical studies showed that OEA remains active when administered orally.

Analysis of chemically synthesized oleoylethanolamide by gas-liquid chromatography.

Oleoylethanolamide (OEA) is known to potentially have beneficial biological effects on weight management by controlling food intake and activating lipid catabolism. In biological fluids, OEA and other endogenously biosynthesized fatty acid ethanolamides are usually analyzed by liquid chromatography-mass spectrometry (LC-MS). The present study provides analytical method to routinely assess the quality of OEA prepared for biological studies by gas-liquid chromatography (GLC). The preparation of OEA for biomedical studies can be performed by N-acylation of oleic acid/esters or using oleoyl chloride. In the present study, OEA was prepared by transamidation of triolein. The analysis of the synthesized OEA has been performed by gas-liquid chromatography of its trimethylsilyl ether (TMS) derivatives. Free OEA cannot be analyzed as such because dehydration of the ethanolamide moiety promptly happens in the GLC injection. This thermal degradation reaction gives rise to the formation of an oxazoline derivative. The TMS moiety prevents the reaction, and the structure of the formed derivative was assessed by mass spectrometry. We show here that OEA prepared for biological studies can be routinely analyzed by GLC after TMS derivative preparation.