There is growing in vivo evidence that the dipeptide carnosine has protective effects in metabolic diseases. A critical unanswered question is whether its site of action is tissues or plasma. This was investigated using oral carnosine versus β-alanine supplementation in a high-fat diet rat model. Thirty-six male Sprague-Dawley rats received a control diet (CON), a high-fat diet (HF; 60% of energy from fat), the HF diet with 1.8% carnosine (HFcar), or the HF diet with 1% β-alanine (HFba), as β-alanine can increase muscle carnosine without increasing plasma carnosine. Insulin sensitivity, inflammatory signaling, and lipoxidative stress were determined in skeletal muscle and blood. In a pilot study, urine was collected. The 3 HF groups were significantly heavier than the CON group. Muscle carnosine concentrations increased equally in the HFcar and HFba groups, while elevated plasma carnosine levels and carnosine-4-hydroxy-2-nonenal adducts were detected only in the HFcar group. Elevated plasma and urine N<sup>3</sup>-(carboxymethyl)lysine in HF rats was reduced by 50% in the HFcar group but not in the HFba group. Likewise, inducible nitric oxide synthase mRNA was decreased by 47% (p < 0.05) in the HFcar group, but not in the HFba group, compared with HF rats. We conclude that plasma carnosine, but not muscle carnosine, is involved in preventing early-stage lipoxidation in the circulation and inflammatory signaling in the muscle of rats.
|Titolo:||Plasma carnosine, but not muscle carnosine, attenuates high-fat diet-induced metabolic stress|
|Parole Chiave:||Advanced glycation end products; Advanced lipoxidation end products; Carnosine conjugates; Inflammatory signaling; Quenching ability; β-alanine; Physiology; Endocrinology, Diabetes and Metabolism; Nutrition and Dietetics; Physiology (medical)|
|Settore Scientifico Disciplinare:||Settore CHIM/08 - Chimica Farmaceutica|
|Data di pubblicazione:||2015|
|Digital Object Identifier (DOI):||10.1139/apnm-2015-0042|
|Appare nelle tipologie:||01 - Articolo su periodico|