β-Alanine supplementation reduces anxiety and increases neurotrophin expression in both young and older rats

Integrative proteomics and metabolomics data analysis exploring the mechanism of brain injury after cardiac surgery in chronic stress rats

OBJECTIVE

Preoperative chronic stress (CS) is associated with postoperative brain injury in patients undergoing open heart cardiac surgery. This research is to explore the potential molecular biological mechanisms of brain damage following cardiac surgery in preoperative CS rats by the analyses combining proteomics and metabolomics.

METHODS

We constructed the chronic unpredictable stress (CUS) and cardiac surgery models in adult rats. We proved the brain injury in CUS cardiac surgery rats by Hematoxylin-Eosin (H&E) staining, followed by separating the hippocampal tissue and investigating the potential mechanisms of brain injury by the methods of data-independent acquisition proteomics and untargeted metabolomics.

RESULTS

The signaling pathways of glycoproteins and metabolism of amino acids were the main possible mechanisms of brain injury in CUS rats following cardiac surgery according to the proteomics and metabolomics. In addition, the pathways of animo acids metabolism such as the pathways of lysine degradation and β-alanine metabolism may be the main mechanism of cardiac surgery related brain injury in preoperative CUS rats.

CONCLUSIONS

The pathways of animo acids metabolism such as lysine degradation and β-alanine metabolism may be the potential mechanisms of brain injury in CUS rats following cardiac surgery. We should focus on the varieties of bioproteins and metabolites in these pathways, and related changes in other signaling pathways induced by the two pathways.

Spatial amine metabolomics and histopathology reveal localized brain alterations in subacute traumatic brain injury and the underlying mechanism of herbal treatment

INTRODUCTION

Spatial changes of amine metabolites and histopathology of the whole brain help to reveal the mechanism of traumatic brain injury (TBI) and treatment.

METHODS

A newly developed liquid microjunction surface sampling-tandem mass tag-ultra performance liquid chromatography-mass spectrometry technique is applied to profile brain amine metabolites in five brain regions after impact-induced TBI at the subacute stage. H&E, Nissl, and immunofluorescence staining are performed to spatially correlate microscopical changes to metabolic alterations. Then, bioinformatics, molecular docking, ELISA, western blot, and immunofluorescence are integrated to uncover the mechanism of Xuefu Zhuyu decoction (XFZYD) against TBI.

RESULTS

Besides the hippocampus and cortex, the thalamus, caudate-putamen, and fiber tracts also show differentiated metabolic changes between the Sham and TBI groups. Fourteen amine metabolites (including isomers such as L-leucine and L-isoleucine) are significantly altered in specific regions. The metabolic changes are well matched with the degree of neuronal damage, glia activation, and neurorestoration. XFZYD reverses the dysregulation of several amine metabolites, such as hippocampal Lys-Phe/Phe-Lys and dopamine. Also, XFZYD enhances post-TBI angiogenesis in the hippocampus and the thalamus.

CONCLUSION

This study reveals the local amine-metabolite and histological changes in the subacute stage of TBI. XFZYD may promote TBI recovery by normalizing amine metabolites and spatially promoting dopamine production and angiogenesis.

The effect of supraphysiological dose of nandrolone decanoate administration on the inflammatory, neurotrophin and behavioral response in adult and old male mice

This study examined the effect of 6 weeks of supraphysiological nandrolone decanoate (ND) administration in adult mice (7 months) on cognitive function and neuroinflammation during aging. Male C57BL/6 mice were randomized into ND (10 mg·kg-1·wk-1) or control (CTL) groups. Half of the mice were tested at a young (Y) age (ND-Y and CTL-Y), 1 week following final ND administration, while the remaining mice were tested at 16 months (O) (ND-O and CTL-O). Learning and memory were better in young mice compared to older mice, regardless of treatment. ND-O displayed decreased anxiety as compared to all other groups. TNFα and IL1β expression were higher in older mice, regardless of treatment. ND administration in young mice appeared to attenuate the neuroinflammatory response in aging mice as evidenced by decreased COX2, IL-4 and increased IL-10 expression in ND-O compared to CTL-O. BDNF AR and ER expression increased in ND-O compared to CTL-O. Results of the study indicated that supraphysiological ND administration had no negative effect on learning and memory but may attenuate anxiety in older mice. In addition, ND administration in young adult mice may attenuate the inflammatory response during aging, which may be related to elevations in both AR and ER expression.

Biochemical Mechanisms of Beneficial Effects of Beta-Alanine Supplements on Cognition

Using nutritional interventions to cure and manage psychiatric disorders is a promising tool. In this regard, accumulating documents support strong relationships between the diet and brain health throughout the lifespan. Evidence from animal and human studies demonstrated that β-alanine (Beta-alanine; BA), a natural amino acid, provides several benefits in fight against cognitive decline promoting mental health. This review summarizes and reports state-of-the-art evidence on how BA affects cognitive health and argues existence of potential unrevealed biochemical mechanisms and signaling cascades. There is a growing body of evidence showing that BA supplement has a significant role in mental health mediating increase of the cell carnosine and brain-derived neurotrophic factor (BDNF) content. BDNF is one of the most studied neurotrophins in the mammalian brain, which activates several downstream functional cascades via the tropomyosin-related kinase receptor type B (TrkB). Activation of TrkB induces diverse processes, such as programmed cell death and neuronal viability, dendritic branching growth, dendritic spine formation and stabilization, synaptic development, cognitive-related processes, and synaptic plasticity. Carnosine exerts its main effect via its antioxidant properties. This critical antioxidant also scavenges hypochlorous acid (HOCl), another toxic species produced in mammalian cells. Carnosine regulates transcription of hundreds of genes related to antioxidant mechanisms by increasing expression of the nuclear erythroid 2-related factor 2 (Nrf2) and translocating Nrf2 to the nucleus. Another major protective effect of carnosine on the central nervous system (CNS) is related to its anti-glycating, anti-aggregate activities, anti-inflammatory, metal ion chelator activity, and regulation of pro-inflammatory cytokine secretion. These effects could be associated with the carnosine ability to form complexes with metal ions, particularly with zinc (Zn2+). Thus, it seems that BA via BDNF and carnosine mechanisms may improve brain health and cognitive function over the entire human lifespan.

The Effect of β-Alanine Supplementation on Performance, Cognitive Function and Resiliency in Soldiers

β-alanine is a nonessential amino acid that combines with the amino acid histidine to form the intracellular dipeptide carnosine, an important intracellular buffer. Evidence has been well established on the ability of β-alanine supplementation to enhance anaerobic skeletal muscle performance. As a result, β-alanine has become one of the more popular supplements used by competitive athletes. These same benefits have also been reported in soldiers. Evidence accumulated over the last few years has suggested that β-alanine can result in carnosine elevations in the brain, which appears to have broadened the potential effects that β-alanine supplementation may have on soldier performance and health. Evidence suggests that β-alanine supplementation can increase resilience to post-traumatic stress disorder, mild traumatic brain injury and heat stress. The evidence regarding cognitive function is inconclusive but may be more of a function of the stressor that is applied during the assessment period. The potential benefits of β-alanine supplementation on soldier resiliency are interesting but require additional research using a human model. The purpose of this review is to provide an overview of the physiological role of β-alanine and why this nutrient may enhance soldier performance.

Role of β-Alanine Supplementation on Cognitive Function, Mood, and Physical Function in Older Adults; Double-Blind Randomized Controlled Study

This study investigated 10 weeks of β-alanine (BA) supplementation on changes in cognitive function, mood, and physical performance in 100 older adults (70.6 ± 8.7 y). Participants were randomized into a BA (2.4 g·d^-1) or placebo (PL) group. Testing occurred prior to supplementation (PRE), at the midpoint (MID), and at week-10 (POST). Participants completed cognitive function assessments, including the Montreal cognitive assessment (MOCA) and the Stroop pattern recognition test, at each testing session. Behavioral questionnaires [i.e., the profile of mood states, geriatric depression scale (GDS), and geriatric anxiety scale (GAS)] and physical function assessments (grip strength and timed sit-to-stand) were also conducted. No difference between groups was noted in MoCA scores (p = 0.19). However, when examining participants whose MOCA scores at PRE were at or below normal (i.e., ≤26), participants in BA experienced significant improvements in MOCA scores at MID (13.6%, p = 0.009) and POST (11.8%, p = 0.016), compared to PL. No differences were noted in mood scores, GAS, or any of the physical performance measures. A significant decrease was observed in the GDS for participants consuming BA but not in PL. Results suggested that BA supplementation can improve cognitive function in older adults whose cognitive function at baseline was at or below normal and possibly reduce depression scores.

β-Alanine Supplementation Attenuates the Neurophysiological Response in Animals Exposed to an Acute Heat Stress

The effect of 30 days of β-alanine supplementation on neurophysiological responses of animals exposed to an acute heat stress (HS) was examined. Animals were randomized to one of three groups; exposed to HS (120 min at 40-41 °C) and fed a normal diet (EXP; n = 12); EXP and supplemented with β-alanine (EXP + BA; n = 10); or not exposed (CTL; n = 10). Hippocampal (CA1, CA3 and DG) and hypothalamic (PVN) immunoreactive (ir) cell numbers of COX2, IBA-1, BDNF, NPY and HSP70 were analyzed. Three animals in EXP and one in EXP-BA did not survive the HS, however no significant difference (p = 0.146) was noted in survival rate in EXP + BA. The % change in rectal temperature was significantly lower (p = 0.04) in EXP + BA than EXP. Elevations (p's < 0.05) in COX-2, IBA-1 and HSP70 ir-cell numbers were noted in animals exposed to HS in all subregions. COX-2 ir-cell numbers were attenuated for EXP + BA in CA1 (p = 0.02) and PVN (p = 0.015) compared to EXP. No difference in COX-2 ir-cell numbers was noted between CTL and EXP + BA at CA1. BDNF-ir cell numbers in CA1, DG and PVN were reduced (p's < 0.05) during HS compared to CTL. No difference in BDNF-ir cell numbers was noted between EXP + BA and CTL in CA3 and PVN. NPY-ir density was reduced in exposed animals in all subregions, but NPY-ir density for EXP-BA was greater than EXP in CA3 (p < 0.001) and PVN (p = 0.04). β-Alanine supplementation attenuated the thermoregulatory and inflammatory responses and maintained neurotrophin and neuropeptide levels during acute HS. Further research is necessary to determine whether β-alanine supplementation can increase survival rate during a heat stress.

β-Alanine and l-histidine supplementation associated with combined training increased functional capacity and maximum strength in heart failure rats

NEW FINDINGS

What is the central question of the study? Does β-alanine with l-histidine supplementation associated with endurance and strength training improve echocardiographic parameters, functional capacity, and maximum strength in rats with chronic heart failure? What is the main finding and its importance? β-Alanine with l-histidine supplementation associated with endurance and strength training increased functional capacity and maximum strength through increasing exercise capacity peripherally but did not affect echocardiographic parameters in rats with chronic heart failure. Combined training (CT) has been associated with positive responses in the clinical status of patients with chronic heart failure (CHF). Other non-pharmacological tools, such as amino acid supplementation, may further enhance its adaptation. However, the effects of β-alanine and l-histidine supplementation in CHF remain unclear. In the present study, the aim was to test whether supplementing carnosine precursors with CT could give improved responses in the functional capacity and echocardiographic variables of rats with CHF. Twenty-four Wistar rats, were submitted to myocardial infarction and allocated to three groups: animals with CHF kept in sedentary conditions (SED, n = 8), animals with CHF submitted to CT in strength and aerobic exercise supplemented with placebo (CT-P, n = 8) and animals with CHF submitted to CT in strength and aerobic exercise supplemented with β-alanine and l-histidine (CT-S, n = 8). The trained animals were submitted to a strength protocol three times per week with intensity of 65-75% of one repetition maximum test. Aerobic training was conducted two times per week (50 min, 15 m min^-1 ). The supplemented group received β-alanine and l-histidine orally (each 250 mg kg^-1  day^-1 ). No changes in echocardiographic and morphological parameters were found among the groups (P > 0.05). Functional capacity, Δ V ̇ O 2 max and maximum strength were higher in CT-P than in SED and even higher in CT-S than in CT-P (P < 0.01). The CT was able to improve functional capacity, but the supplementation was shown to enhance these parameters even further in the CHF rats. We conclude that the increase in functional capacity and strength gained through CT and supplementation were associated with the improvement in peripheral parameters with no changes in cardiac variables.

Effect of β-alanine supplementation on carnosine and histidine content in the hippocampus of 14-month-old rats

Carnosine and histidine content in the hippocampus of 14-month-old male rats was examined following 30 days of β-alanine supplementation. All animals were provided identical diets; however, 100 mg of β-alanine was mixed with glucomannan (80:20 blend) in the water of β-alanine supplemented animals. Hippocampal carnosine content was significantly greater (p = 0.005) for β-alanine compared with control, while no differences (p = 0.438) were noted in histidine content between groups. Results provide initial evidence that β-alanine supplementation increases carnosine content in the hippocampus of middle-aged rats, without compromising histidine content. β-Alanine supplementation increases hippocampal carnosine content without compromising histidine content in middle-aged rats.

The Potential of Carnosine in Brain-Related Disorders: A Comprehensive Review of Current Evidence

Neurological, neurodegenerative, and psychiatric disorders represent a serious burden because of their increasing prevalence, risk of disability, and the lack of effective causal/disease-modifying treatments. There is a growing body of evidence indicating potentially favourable effects of carnosine, which is an over-the-counter food supplement, in peripheral tissues. Although most studies to date have focused on the role of carnosine in metabolic and cardiovascular disorders, the physiological presence of this di-peptide and its analogues in the brain together with their ability to cross the blood-brain barrier as well as evidence from in vitro, animal, and human studies suggest carnosine as a promising therapeutic target in brain disorders. In this review, we aim to provide a comprehensive overview of the role of carnosine in neurological, neurodevelopmental, neurodegenerative, and psychiatric disorders, summarizing current evidence from cell, animal, and human cross-sectional, longitudinal studies, and randomized controlled trials.