Carnosine and its (S)-Trolox™ derivative protect animals against oxidative stress

Acute balenine supplementation in humans as a natural carnosinase-resistant alternative to carnosine

Balenine possesses some of carnosine's and anserine's functions, yet it appears more resistant to the hydrolysing CN1 enzyme. The aim of this study was to elucidate the stability of balenine in the systemic circulation and its bioavailability in humans following acute supplementation. Two experiments were conducted in which (in vitro) carnosine, anserine and balenine were added to plasma to compare degradation profiles and (in vivo) three increasing doses (1-4-10 mg/kg) of balenine were acutely administered to 6 human volunteers. Half-life of balenine (34.9 ± 14.6 min) was respectively 29.1 and 16.3 times longer than that of carnosine (1.20 ± 0.36 min, p = 0.0044) and anserine (2.14 ± 0.58 min, p = 0.0044). In vivo, 10 mg/kg of balenine elicited a peak plasma concentration (Cmax) of 28 µM, which was 4 and 18 times higher than with 4 (p = 0.0034) and 1 mg/kg (p = 0.0017), respectively. CN1 activity showed strong negative correlations with half-life (ρ = - 0.829; p = 0.0583), Cmax (r = - 0.938; p = 0.0372) and incremental area under the curve (r = - 0.825; p = 0.0433). Overall, balenine seems more resistant to CN1 hydrolysis resulting in better in vivo bioavailability, yet its degradation remains dependent on enzyme activity. Although a similar functionality as carnosine and anserine remains to be demonstrated, opportunities arise for balenine as nutraceutical or ergogenic aid.

Identification of Metabonomics Changes in Longissimus Dorsi Muscle of Finishing Pigs Following Heat Stress through LC-MS/MS-Based Metabonomics Method

Simple Summary

Limited research exists on muscle metabolomics of finishing pigs under heat stress. In this study, nine different metabolites in the longissimus dorsi (LD) muscle of finishing pigs under heat stress were screened and identified. Through quantitative verification, it was concluded that the content of L-carnitine in the LD muscles of the finishing pigs could be significantly decreased due to heat stress, which might be a biomarker for monitoring the animal health status and muscle quality under heat stress.

Abstract

Heat stress (HS) negatively affects meat quality by affecting material and energy metabolism, and exploring the mechanism underlying the muscle response to chronic HS in finishing pigs is important for the global pork industry. This study investigated changes in the metabolic profiles of the longissimus dorsi (LD) muscle of finishing pigs under high temperature using ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC-ESI-QTOF-MS) and multivariate data analysis (MDA). Castrated male DLY pigs (Duroc × Landrance × Yorkshire pigs, n = 24) from 8 litters were divided into three treatment groups: constant optimal ambient temperature at 22 °C and ad libitum feeding (CR, n = 8); constant high ambient temperature at 30 °C and ad libitum feeding (HS, n = 8); and constant optimal ambient temperature 22 °C and pair-feeding to the control pigs (PF, n = 8). The metabolic profile data from LD muscle samples were analyzed by MDA and external search engines. Nine differential metabolites (L-carnosine, acetylcholine, inosinic acid, L-carnitine, L-anserine, L-α-glycerylphosphorylcholine, acetylcarnitine, thiamine triphosphate, and adenosine thiamine diphosphate) were involved in antioxidant function, lipid metabolism, and cell signal transduction, which may decrease post mortem meat quality and play important roles in anti-HS. Four metabolites (L-carnosine, acetylcholine, inosinic acid, and L-carnitine) were verified, and it was indicated that the muscle L-carnitine content was significantly lower in HS than in CR (p < 0.01). The results show that constant HS affects the metabolites in the LD muscle and leads to coordinated changes in the endogenous antioxidant defense and meat quality of finishing pigs. These metabonomics results provide a basis for researching nutritional strategies to reduce the negative effects of heat stress on livestock and present new insights for further research.

Carnosine as an effective neuroprotector in brain pathology and potential neuromodulator in normal conditions

Carnosine (b-alanyl-L-histidine) is an endogenous dipeptide widely distributed in excitable tissues, such as muscle and neural tissues-though in minor concentrations in the latter. Multiple benefits have been attributed to carnosine: direct and indirect antioxidant effect, antiglycating, metal-chelating, chaperone and pH-buffering activity. Thus, carnosine turns out to be a multipotent protector against oxidative damage. However, the role of carnosine in the brain remains unclear. The key aspects concerning carnosine in the brain reviewed are as follows: its concentration and bioavailability, mechanisms of action in neuronal and glial cells, beneficial effects in human studies. Recent literature data and the results of our own research are summarized here. This review covers studies of carnosine effects on both in vitro and in vivo models of cerebral damage, such as neurodegenerative disorders and ischemic injuries and the data on its physiological actions on neuronal signaling and cerebral functions. Besides its antioxidant and homeostatic properties, new potential roles of carnosine in the brain are discussed.

Carnosine ameliorates liver fibrosis and hyperammonemia in cirrhotic rats

AIM

Chronic liver injury and cirrhosis leads to liver failure. Hyperammonemia is a deleterious consequence of liver failure. On the other hand, oxidative stress seems to play a pivotal role in the pathogenesis of liver fibrosis as well as in the cytotoxic mechanism of ammonia. There is no promising therapeutic agent against ammonia-induced complications. The present study was conducted to evaluate the role of carnosine (CA) administration on liver pathological changes, elevated plasma ammonia, and its consequent events in cirrhotic rats.

METHODS

Bile duct ligated (BDL) rats were used as a model of cirrhosis. CA (250, 500, and 1000mg/kg, daily, i.p) was administered for 28 consecutive days to BDL animals. At the end of treatments, markers of oxidative stress and liver fibrosis was determined in liver and serum biomarkers of liver injury and plasma ammonia was assessed. Moreover, changes in animals' locomotor activity were monitored.

RESULTS

Severe bridging fibrosis, inflammation, and necrosis in liver, along with elevated serum biomarkers of liver injury were evident in BDL animals. Furthermore, plasma ammonia was drastically elevated in cirrhotic rats and animals' locomotor activity was suppressed. It was found that CA (250, 500, and 1000mg/kg, daily, i.p) significantly alleviated liver injury and its consequent events in cirrhotic rats. The data suggested that CA is not only a useful and safe agent to preserve liver function, but also prevented hyperammonemia and brain damage as a deleterious consequence of cirrhosis and liver failure.

Evaluation of the effect of carnosine, its novel derivative trolox-carnosine and trolox in a pre-clinical study focussing on the regulation of immunity

The neuroprotective or neurotoxic effects of the products of the kynurenine pathway of tryptophan metabolism highly depend on the action of kynurenine-3-monooxygenase (KMO). The present results show increased concentrations of the KMO in the plasma of rats repeatedly exposed to an immune challenge. Increased concentrations of this key enzyme are likely to cause a shift of kynurenine pathway towards enhanced production of neurotoxic metabolites.

Inhibition of oxidative stress in brain during rat adjuvant arthritis by carnosine, trolox and novel trolox-carnosine

Carnosine (CARN) is an anti-glycating agent able to quench superoxide, and to neutralize 4-hydroxynonenal. Trolox-carnosine (CARN-T) was synthesized because of its resistance against degradation and to improve CARN antioxidant capacity. We evaluated the impact of trolox (TRO), CARN and its derivative CARN-T on oxidative stress (OS) in brain during rat adjuvant arthritis (AA). The experiments were done on healthy, control arthritic and arthritic animals with administration of CARN 150 mg/kg b.w., TRO 41 mg/kg b.w. and CARN-T 75 mg/kg b.w. in a daily dose during 28 days. Antioxidants did not affect the body weight on day 14, but on day 28 TRO enhanced the weight reduction. On day 14 and 28 CARN-T and TRO reduced arthritic score. IL-1beta, MCP-1 and MMP-9 were measured in plasma on day 14. MCP-1 was decreased by CARN-T and TRO. All antioxidants reduced IL-1beta and MMP-9 levels. Malondialdehyde, 4-hydroxynonenal and protein carbonyls were increased in brain. CARN, CARN-T and TRO prevented higher lipid and protein oxidation in brain. CARN and CARN-T caused no weight reduction like TRO that has an advantage in inflammatory arthritis. Moreover the antioxidants administered had a similar therapeutic effects on arthritic score, markers of inflammation in plasma and OS in brain.

Effects of β-alanine administration on selected parameters of oxidative stress and phosphoryltransfer network in cerebral cortex and cerebellum of rats

β-Alanine is a β-amino acid derivative of the degradation of pyrimidine uracil and precursor of the oxidative substrate acetyl-coenzyme A (acetyl-CoA). The accumulation of β-alanine occurs in β-alaninemia, an inborn error of metabolism. Patients with β-alaninemia may develop neurological abnormalities whose mechanisms are far from being understood. In this study we evaluated the effects of β-alanine administration on some parameters of oxidative stress and on creatine kinase, pyruvate kinase, and adenylate kinase in cerebral cortex and cerebellum of 21-day-old rats. The animals received three peritoneal injections of β-alanine (0.3 mg /g of body weight) and the controls received the same volume (10 μL/g of body weight) of saline solution (NaCl 0.85 %) at 3 h intervals. CSF levels of β-alanine increased five times, achieving 80 μM in the rats receiving the amino acid. The results of β-alanine administration in the parameters of oxidative stress were similar in both tissues studied: reduction of superoxide dismutase activity, increased oxidation of 2',7'-dihydrodichlorofluorescein, total content of sulfhydryl and catalase activity. However, the results of the phosphoryltransfer network enzymes were similar in all enzymes, but different in the tissues studied: the β-alanine administration was able to inhibit the enzyme pyruvate kinase, cytosolic creatine kinase, and adenylate kinase activities in cerebral cortex, and increase in cerebellum. In case this also occurs in the patients, these results suggest that oxidative stress and alteration of the phosphoryltransfer network may be involved in the pathophysiology of β-alaninemia. Moreover, the ingestion of β-alanine to improve muscular performance deserves more attention in respect to possible side-effects.