Effects of carnosine and anserine on muscle and non-muscle phosphorylases

Mechanisms of carnosine-induced activation of neuronal cells

Carnosine (β-Ala-l-His), an imidazole dipeptide, is known to have many functions. Recently, we demonstrated in a double-blind randomized controlled trial that carnosine is capable of preserving cognitive function in elderly people. In the current study, we assessed the ability of carnosine to activate the brain, and we tried to clarify the molecular mechanisms behind this activation. Our results demonstrate that carnosine permeates the blood brain barrier and activates glial cells within the brain, causing them to secrete neurotrophins, including BDNF and NGF. These results point to a novel mechanism of carnosine-induced neuronal activation. Our results suggest that carnosine should be recognized as a functional food factor that helps achieve anti-brain aging.

Carnosine activates the CREB pathway in Caco-2 cells

Imidazole dipeptide, carnosine, is a versatile compound composed of β-Ala and L-His. A recent study showed that carnosine might benefit the treatment of Alzheimer's disease and the maintenance of cognitive function. Based on the observation that carnosine is immediately degraded by serum carnosinase, we hypothesized that carnosine improves brain function by promoting brain-gut interaction. This study sought to present possible mechanisms regulating carnosine-induced activation of brain-gut interaction. We had previously found that carnosine augmented the expression of BDNF in human colorectal cancer cells, thus we became interested in cAMP-responsive element binding protein (CREB), which is a dominant regulator of BDNF transcription. We found that carnosine activates CREB and CREB-related pathways by activating Ca²⁺-related pathways. Our findings suggest that carnosine augments the expression of CREB-regulated genes in the intestine; this augmentation contributes to the carnosine-induced activation of brain-gut interaction.

The effect of β-alanine and NaHCO3 co-ingestion on buffering capacity and exercise performance with high-intensity exercise in healthy males

INTRODUCTION

β-alanine (BAl) and NaHCO3 (SB) ingestion may provide performance benefits by enhancing concentrations of their respective physiochemical buffer counterparts, muscle carnosine and blood bicarbonate, counteracting acidosis during intense exercise. This study examined the effect of BAl and SB co-supplementation as an ergogenic strategy during high-intensity exercise.

METHODS

Eight healthy males ingested either BAl (4.8 g day(-1) for 4 weeks, increased to 6.4 g day(-1) for 2 weeks) or placebo (Pl) (CaCO3) for 6 weeks, in a crossover design (6-week washout between supplements). After each chronic supplementation period participants performed two trials, each consisting of two intense exercise tests performed over consecutive days. Trials were separated by 1 week and consisted of a repeated sprint ability (RSA) test and cycling capacity test at 110 % Wmax (CCT110 %). Placebo (Pl) or SB (300 mg kgbw(-1)) was ingested prior to exercise in a crossover design to creating four supplement conditions (BAl-Pl, BAl-SB, Pl-Pl, Pl-SB).

RESULTS

Carnosine increased in the gastrocnemius (n = 5) (p = 0.03) and soleus (n = 5) (p = 0.02) following BAl supplementation, and Pl-SB and BAl-SB ingestion elevated blood HCO3 (-) concentrations (p < 0.01). Although buffering capacity was elevated following both BAl and SB ingestion, performance improvement was only observed with BAl-Pl and BAl-SB increasing time to exhaustion of the CCT110 % test 14 and 16 %, respectively, compared to Pl-Pl (p < 0.01).

CONCLUSION

Supplementation of BAl and SB elevated buffering potential by increasing muscle carnosine and blood bicarbonate levels, respectively. BAl ingestion improved performance during the CCT110 %, with no aggregating effect of SB supplementation (p > 0.05). Performance was not different between treatments during the RSA test.

Carnosine prevents apoptosis of glomerular cells and podocyte loss in STZ diabetic rats

BACKGROUND/AIMS

We identified carnosinase-1 (CN-1) as risk-factor for diabetic nephropathy (DN). Carnosine, the substrate for CN-1, supposedly is a protective factor regarding diabetic complications. In this study, we hypothesized that carnosine administration to diabetic rats might protect the kidneys from glomerular apoptosis and podocyte loss.

METHODS

We examined the effect of oral L-carnosine administration (1g/kg BW per day) on apoptosis, podocyte loss, oxidative stress, AGEs and hexosamine pathway in kidneys of streptozotocin-induced diabetic Wistar rats after 3 months of diabetes and treatment.

RESULTS

Hyperglycemia significantly reduced endogenous kidney carnosine levels. In parallel, podocyte numbers significantly decreased (-21% compared to non-diabetics, p<0.05), apoptotic glomerular cells numbers increased (32%, compared to non-diabetic, p<0.05) and protein levels of bax and cytochrome c increased (175% and 117%). Carnosine treatment restored carnosine kidney levels, prevented podocytes loss (+23% compared to diabetic, p<0.05), restrained glomerular apoptosis (-34% compared to diabetic; p<0.05) and reduced expression of bax and cytochrome c (-63% and -54% compared to diabetics, both p<0.05). In kidneys of all diabetic animals, levels of ROS, AGEs and GlcNAc-modified proteins were increased.

CONCLUSION

By inhibition of pro-apoptotic signaling and independent of biochemical abnormalities, carnosine protects diabetic rat kidneys from apoptosis and podocyte loss.

Effects of beta-alanine on muscle carnosine and exercise performance: a review of the current literature

Muscle carnosine has been reported to serve as a physiological buffer, possess antioxidant properties, influence enzyme regulation, and affect sarcoplasmic reticulum calcium regulation. Beta-alanine (β-ALA) is a non-essential amino acid. β-ALA supplementation (e.g., 2-6 grams/day) has been shown to increase carnosine concentrations in skeletal muscle by 20-80%. Several studies have reported that β-ALA supplementation can increase high-intensity intermittent exercise performance and/or training adaptations. Although the specific mechanism remains to be determined, the ergogenicity of β-ALA has been most commonly attributed to an increased muscle buffering capacity. More recently, researchers have investigated the effects of co-ingesting β-ALA with creatine monohydrate to determine whether there may be synergistic and/or additive benefits. This paper overviews the theoretical rationale and potential ergogenic value of β-ALA supplementation with or without creatine as well as provides future research recommendations.

Calcium sensitizing action of carnosine and other endogenous imidazoles in chemically skinned striated muscle

1. The imidazole-containing compounds carnosine and homocarnosine, endogenous to skeletal and cardiac muscle, have been tested for effect on the contractile behaviour of chemically skinned (saponin or Triton X-100) skeletal and cardiac muscle. 2. Carnosine, at millimolar concentrations which are near physiological for many skeletal fibres, and in a concentration-dependent fashion, shifts the curve relating [Ca2+] to steady-state tension to lower [Ca2+] in both skeletal (frog but not crab) and cardiac (rat) muscle preparations. 3. Of other imidazoles endogenous to heart, homocarnosine is somewhat more effective, while N-acetyl L-histidine is much less so. 4. The maximum level of Ca(2+)-activated force is increased significantly by homocarnosine in cardiac trabeculae. 5. We propose that the cellular imidazoles related to carnosine are natural 'Ca2+ sensitizers' in striated muscle. Alterations in their levels as a result of disease or training, and between different fibre types, may contribute to differences in contractile performance of the intact tissues.