Protective effects of carnosine against protein modification mediated by malondialdehyde and hypochlorite

Inhibitory Potential of Carnosine and Aminoguanidine Towards Glycation and Fibrillation of Albumin: In-vitro and Simulation Studies

Carnosine is beta-alanyl histidine, a dipeptide, endogenously produced in our body by the carnosine synthase enzyme. It is an antioxidant, thus protecting from the deleterious effect of advanced glycation end products (AGEs). Similarly, aminoguanidine (AG) also prevents AGEs formation by scavenging free radicals such as reactive oxygen species (ROS)/reactive carbonyl species (RCS). This study used experimental and computational techniques to perform a comparative analysis of carnosine and AG and their inhibiting properties against glycated human serum albumin (HSA). Fructose-mediated glycation of albumin produced fluorescent structures, such as pentosidine and malondialdehyde. These AGEs were significantly reduced by carnosine and AG. At 20 mM, carnosine and AG quenches pentosidine fluorescence by 66% and 83%, respectively. A similar inhibitory effect was observed for malondialdehyde. Protein hydrophobicity and tryptophan fluorescence were restored in the presence of carnosine and AG. Aminoguanidine decreased fibrillation in HSA, while carnosine did not significantly affect aggregation/fibrillation. In addition, molecular docking study observed binding scores of -5.90 kcal/mol and -2.59 kcal/mol by HSA-aminoguanidine and HSA-carnosine complex, respectively. Aminoguanidine forms one conventional hydrogen bond with ARG A:10 and a salt bridge with ASP A:13, ASP A:259, ASP A:255, and ASP A:256 from the amine group. Similarly, carnosine forms only hydrogen bonds with GLU A:501 and GLN A:508 from the amine and hydroxy group. The root mean square deviation (RMSD) calculated from simulation studies was 1 nm upto 70 ns for the HSA-aminoguanidine complex and the spectrum of HSA-carnosine was significantly deviated and not stabilized. The superior inhibitory activity of aminoguanidine could be due to additional salt bridge bonding with albumin. Conclusively, aminoguanidine can be the better treatment choice for diabetes-associated neurological diseases.

Relationship between Beef Quality and Bull Breed

The beef industry in Poland heavily relies on the Polish Holstein-Friesian (PHF) breed, known for its primary use in dairy production, but which also contributes significantly to the beef supply. In contrast, the Limousine (LM), Hereford (HH), and Charolaise (CH) breeds have gained popularity due to their ideal specialized characteristics for beef production. As PHF continues to dominate the beef market, a thorough comparison of its beef quality and nutritional attributes with the three most popular beef breeds in Poland is essential. This study aims to address this knowledge gap by conducting a rigorous comparison. The experiment was carried out on the beef from 67 bulls kept in a free-stall system with standardized feeding. The highest total antioxidant status (TAS) was found in CH and was 147.5% higher than that in PHF. Also, compared with PHF, a large difference of 70% was observed in LM, while in HH it was only 6.25%. For degree of antioxidant potential (DAP), the highest concentration was found in LM, while CH had a slightly lower score than LM. PHF had the lowest scores for each of the analyzed parameters of protein fraction. For anserine, taurine, creatinine, and creatine content, the highest results were found for LM. For carnosine and coenzyme Q10, the highest values were found for CH. Overall, these results highlight the impact of maturity and breed on carcass composition and quality. Late-maturing breeds, such as LM and CH, tend to exhibit leaner carcasses with superior fatty acid profiles and antioxidant properties. This knowledge is valuable for producers, enabling them to make informed decisions regarding breed selection and production strategies to meet specific market demands for beef with the desired composition and quality.

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.

Impact of quercetin, carnosine, and ozone in the cryopreservation on Nellore (Bos indicus) semen

The objective of this study was to reduce the effects of cryoinjury caused in bovine semen by cryopreservation. Ejaculates were collected from Nellore bulls and subjected to freezing in C (control), ozone (15, 30, and 60 µg mL^-1 of ozone), quercetin (25, 50, and 100 µg mL^-1 of quercetin), and carnosine groups (100, 200, and 300 ng mL^-1 of carnosine). Samples were evaluated post-thaw (M0) and post-rapid thermoresistance test (M30) for sperm kinetics (total motility, progressive motility, curvilinear speed, linearity and amplitude of lateral head displacement) and cell structure viability (plasma membrane integrity, acrosomal integrity, mitochondrial potential, membrane fluidity, and lipid peroxidation). There were no differences (P > 0.05) between the control, quercetin, and carnosine-treated groups for the parameters evaluated at M0 and M30. In turn, supplementation with ozone resulted in lower values for sperm kinetics (P < 0.05) and lower mitochondrial potential at M30 (P < 0.05). Quercetin and carnosine at the concentrations used did not promote significant gains in frozen semen, nor did they demonstrate cytotoxicity. We expected to obtain positive results with the use of ozone. Nonetheless, the addition was harmful to the parameters of sperm kinetics, and its effect was not observed as a possible pro-antioxidant. We believe that the fact that the gas did not harm the sperm structure opens avenues for tests with lower dosages, since, by reducing its concentration, we could minimize the damage to sperm kinetics.

Novel insights into alcoholic liver disease: Iron overload, iron sensing and hemolysis

The liver is the major target organ of continued alcohol consumption at risk and resulting alcoholic liver disease (ALD) is the most common liver disease worldwide. The underlying molecular mechanisms are still poorly understood despite decades of scientific effort limiting our abilities to identify those individuals who are at risk to develop the disease, to develop appropriate screening strategies and, in addition, to develop targeted therapeutic approaches. ALD is predestined for the newly evolving translational medicine, as conventional clinical and health care structures seem to be constrained to fully appreciate this disease. This concept paper aims at summarizing the 15 years translational experience at the Center of Alcohol Research in Heidelberg, namely based on the long-term prospective and detailed characterization of heavy drinkers with mortality data. In addition, novel experimental findings will be presented. A special focus will be the long-known hepatic iron accumulation, the somewhat overlooked role of the hematopoietic system and novel insights into iron sensing and the role of hepcidin. Our preliminary work indicates that enhanced red blood cell (RBC) turnover is critical for survival in ALD patients. RBC turnover is not primarily due to vitamin deficiency but rather to ethanol toxicity directly targeted to erythrocytes but also to the bone marrow stem cell compartment. These novel insights also help to explain long-known aspects of ALD such as mean corpuscular volume of erythrocytes (MCV) and elevated aspartate transaminase (GOT/AST) levels. This work also aims at identifying future projects, naming unresolved observations, and presenting novel hypothetical concepts still requiring future validation.

Reaction Mechanisms of Histidine and Carnosine with Hypochlorous Acid Along with Chlorination Reactivity of N-Chlorinated Intermediates: A Computational Study

Hypochlorous acid (HOCl) released from activated leukocytes not only plays a significant role in the human immune system but is also implicated in numerous diseases including atherosclerosis and some cancers due to its inappropriate production. Histidine (His) and carnosine (Car), as a respective mediator and protective agent of HOCl damage, have attracted considerable attention; however, their detailed reaction mechanisms are still unclear. In this study, using a His residue with two peptide bond groups (HisRes) as a model, the reaction mechanisms of HisRes and Car including N_εH and N_δH tautomers with HOCl along with the chlorination reactivity of N-chlorinated intermediates were investigated by quantum chemical methods. The obtained results indicate that in the imidazole side chain, the pyridine-like N is the most reactive site rather than the pyrrole-like N, and the kinetic order of all of the possible reaction sites in HisRes follows pyridine-like N > imidazole C_δ ≫ imidazole C_ε > pyrrole-like N, while that in Car is pyridine-like N ≫ imidazole C_δ ≫ amide N. As for N-chlorinated intermediates at imidazole, although the unprotonated form has a low chlorination reactivity as expected, it can still chlorinate tyrosine. Especially, the protonated form exhibits similar ability to HOCl, causing secondary damage in vivo. N-Chlorinated Car features higher internal chlorine migration ability than its intermolecular transchlorination, preventing further HOCl-induced damage. Additionally, a generally overlooked nucleophilic Cl^- shift is also found in N-chlorinated Car/HisRes, indicating that nucleophilic sites in biomolecules also need to be considered. The outcomes of this study are expected to expand our understanding of secondary damage and protective mechanisms involved in HOCl in humans.

Inhibitory Effects of Six Types of Tea on Aging and High-Fat Diet-Related Amyloid Formation Activities

Aging and lipid metabolism disorders promote the formation and accumulation of amyloid with β-sheet structure, closely related to cardiovascular disease, senile dementia, type 2 diabetes, and other senile degenerative diseases. In this study, five representative teas were selected from each of the six types of tea, and a total of 30 teas were selected to evaluate the inhibitory activities on the formation of aging-related amyloid in vitro. The results showed that the 30 teas had a significant inhibitory effect on the formation activity on aging-related amyloid at the protein level in vitro. Although the content of catechins is relatively low, black tea and dark tea still have significant antioxidant activity and inhibit the formation of amyloid. A high-fat diet established the model of lipid metabolism disorder in premature aging SAMP8 mice, and these mice were gavaged different tea water extracts. The results showed that different tea types have a significant inhibitory effect on the formation of β-amyloid and Aβ42 mediated by age-related lipid metabolism disorders, and the in vivo activity of fully fermented teas was better than that of green tea. The action mechanism was related to antioxidation, anti-inflammatory, and improving lipid metabolism.

Influence of Imidazole-Dipeptides on Cognitive Status and Preservation in Elders: A Narrative Review

The worldwide increase in the number of patients with dementia is becoming a growing problem, while Alzheimer’s disease (AD), a primary neurodegenerative disorder, accounts for more than 70% of all dementia cases. Research on the prevention or reduction of AD occurrence through food ingredients has been widely conducted. In particular, histidine-containing dipeptides, also known as imidazole dipeptides derived from meat, have received much attention. Imidazole dipeptides are abundant in meats such as poultry, fish, and pork. As evidenced by data from recent human intervention trials conducted worldwide, daily supplementation of carnosine and anserine, which are both imidazole dipeptides, can improve memory loss in the elderly and reduce the risk of developing AD. This article also summarizes the latest researches on the biochemical properties of imidazole dipeptides and their effects on animal models associated with age-related cognitive decline. In this review, we focus on the results of human intervention studies using supplements of poultry-derived imidazole dipeptides, including anserine and carnosine, affecting the preservation of cognitive function in the elderly, and discuss how imidazole dipeptides act in the brain to prevent age-related cognitive decline and the onset of dementia.

Carnosine and Kidney Diseases: What We Currently Know?

Carnosine (beta-alanyl-L-histidine) is an endogenously synthesised dipeptide which is present in different human tissues e.g. in the kidney. Carnosine is degraded by enzyme serum carnosinase, encoding by CNDP1 gene. Carnosine is engaged in different metabolic pathways in the kidney. It reduces the level of proinflammatory and profibrotic cytokines, inhibits advanced glycation end products' formation, moreover, it also decreases the mesangial cell proliferation. Carnosine may also serve as a scavenger of peroxyl and hydroxyl radicals and a natural angiotensin-converting enzyme inhibitor. This review summarizes the results of experimental and human studies concerning the role of carnosine in kidney diseases, particularly in chronic kidney disease, ischemia/reperfusion-induced acute renal failure, diabetic nephropathy and also drug-induced nephrotoxicity. The interplay between serum carnosine concentration and serum carnosinase activity and polymorphism in the CNDP1 gene is discussed. Carnosine has renoprotective properties. It has a promising potential for the treatment and prevention of different kidney diseases, particularly chronic kidney disease which is a global public health issue. Further studies of the role of carnosine in the kidney may offer innovative and effective strategies for the management of kidney diseases.

Susceptibility of epididymal sperm against reactive oxygen species in dogs

In order to add information to physiology of sperm maturation and help to underline future antioxidant supplementation treatment to epididymal sperm, the aim of this study was to evaluate susceptibility of caput, corpus and cauda epididymal sperm to different reactive oxygen species (ROS) in dogs. Epididymal sperm was separately collected from each segment (caput, corpus and cauda) and subjected to 4 different ROS-challenges: superoxide anion, hydrogen peroxide, hydroxyl radical, malondialdehyde (MDA) or maintained as control. After 30 min of incubation in each ROS, sperm was evaluated for sperm kinetics, plasma and acrossomal membrane integrity, mitochondrial activity and resistance to oxidative stress. Decreased total and progressive sperm motility and rapid velocity at epididymal corpus occurred after exposure to hydrogen peroxide, hydroxyl radical and MDA. However, for cauda epididymis, hydrogen peroxide and malondialdehyde promoted higher deleterious effect regarding sperm motility and velocity. Only at cauda epididymis MDA decreased sperm mitochondrial activity index and no kinetics alterations (motility or velocity) occurred after exposure to superoxide anion in corpus and cauda epididymis. In conclusion, corpus and cauda epididymal sperm are highly susceptible to deleterious effect of hydrogen peroxide, malondialdehyde and hydroxyl radical. In addition, epididymal canine sperm is relatively resistant to superoxide anion damage.

Oxidative stress and acid-base balance during the transition period of neonatal Holstein calves submitted to different calving times and obstetric assistance

During the neonatal period, constant adaptations to the extrauterine environment are required. These adaptations are made impossible or hindered when unexpected obstetrical events take place. This study aimed to identify clinical changes of vitality, metabolic and acid-base balance, and oxidative stress of newborn calves born to assisted dams that experienced different durations of calving. A prospective and observational study was conducted with 44 Holstein calves allocated to 3 groups according to the duration of calving: 2 h (n = 16), 2-4 h (n = 16), and >4 h (n = 12), and to 2 subgroups: spontaneous calving (n = 22) and assisted calving (n = 22). We observed that obstetric assistance was beneficial when calving lasted more than 4 h, because 100% of assisted calves had a high Apgar score (≥7) at 5 min, similar to that of spontaneously born calves after 2 h of calving. Rectal temperature of all calves remained within normal values, albeit with a reduction at 20 min of life. Calves born after a calving time >4 h had the highest rectal temperatures, especially those that required obstetrical assistance. There was a progressive increase in blood oxygenation with time, but calves in the >4 h group showed the highest partial pressure of carbon dioxide at birth, whereas calves in the 2 h and 2-4 h groups had lower values. A decrease in partial pressure of CO₂ was observed at 120 min in the 2-4 h and >4 h groups. In the 2-4 h group, calves with obstetrical assistance had higher oxidative stress (measured as thiobarbituric acid reactive substances, TBARS) at 120 min of life compared with that at birth. In spontaneously born calves, TBARS increased only after 240 min. In the >4 h group, TBARS increased progressively with time, regardless of obstetrical subgroup. Calves born spontaneously within the 2 h group had higher TBARS values at birth than calves in the >4 h group with obstetrical assistance. Calves in the >4 h group showed higher levels of glutathione peroxidase (an antioxidant enzyme) at birth than those in the remaining groups. Glutathione peroxidase decreased at 120 min in the >4 h group and at 240 min for the 2 h and 2-4 h groups. In conclusion, obstetric assistance did not improve neonatal vitality and blood oxygenation when calving lasted less than 2 h. Calves born after 2 h of calving showed decreased vitality, hypercapnia, hypoxemia, and increased antioxidant status (glutathione peroxidase).

Effects of β-Alanine Supplementation on Carnosine Elevation and Physiological Performance

β-Alanine is one of the more popular sport supplements used by strength/power athletes today. The popularity of β-alanine stems from its ability to enhance intracellular muscle-buffering capacity thereby delaying fatigue during high-intensity exercise by increasing muscle carnosine content. Recent evidence also suggests that elevated carnosine levels may enhance cognitive performance and increase resiliency to stress. These benefits are thought to result from carnosine's potential role as an antioxidant. This review will discuss these new findings including recent investigations examining β-alanine supplementation and increased resiliency to posttraumatic stress and mild traumatic brain injury. This review will focus on the physiology of carnosine, the effect of β-alanine ingestion on carnosine elevations, and the potential ergogenic benefits it has for competitive and tactical athletes.

Investigations on in vitro anti-carcinogenic potential of L-carnosine in liver cancer cells

This study was carried out to investigate the anti-carcinogenic effect of L-carnosine in human carcinoma cells (SNU-423). The SNU-423 cancer cells were cultured at a density of 2 × 10⁴ cells/well in Dulbecco modified Eagle medium. After 24 h of adherence, the cells were treated with L-carnosine (0.2 and 1 mg/mL) for 48 h. Then, cell viability was assessed by sulforhodamine assay, while mitochondrial dysfunction was measured by fluorescence microscopy using chromatin-specific dye Hoechst 33258. Intracellular levels of ROS were assayed by fluorescence spectroscopy with 2',7'-dichlorofluorescein diacetate (DCFDA). L-Carnosine significantly inhibited the growth of the SNU-423 cells (p < 0.05). The inhibitory effect of L-carnosine was confirmed by results from mitochondrial fragmentation assay. The relative fluorescent unit was increased in a dose-dependent manner by L-carnosine, with values of 79.43, 186.87 and 400.89 for 0.6, 0.8 and 1 mg/mL of L-carnosine, respectively (p < 0.05). These results demonstrate that L-carnosine exerts anti-carcinogenic effects in human liver cancer cells.

New dinitrosyl iron complexes bound with physiologically active dipeptide carnosine

Dinitrosyl iron complexes (DNICs) are physiological NO derivatives and account for many NO functions in biology. Polyfunctional dipeptide carnosine (beta-alanyl-L-histidine) is considered to be a very promising pharmacological agent. It was shown that in the system containing carnosine, iron ions and Angeli's salt, a new type of DNICs bound with carnosine as ligand {(carnosine)₂-Fe-(NO)₂}, was formed. We studied how the carbonyl compound methylglyoxal influenced this process. Carnosine-bound DNICs appear to be one of the cell's adaptation mechanisms when the amount of reactive carbonyl compounds increases at hyperglycemia. These complexes can also participate in signal and regulatory ways of NO and can act as protectors at oxidative and carbonyl stress conditions.

L-carnosine enhanced reproductive potential of the Saccharomyces cerevisiae yeast growing on medium containing glucose as a source of carbon

Carnosine is an endogenous dipeptide composed of β-alanine and L-histidine, which occurs in vertebrates, including humans. It has a number of favorable properties including buffering, chelating, antioxidant, anti-glycation and anti-aging activities. In our study we used the Saccharomyces cerevisiae yeast as a model organism to examine the impact of L-carnosine on the cell lifespan. We demonstrated that L-carnosine slowed down the growth and decreased the metabolic activity of cells as well as prolonged their generation time. On the other hand, it allowed for enhancement of the yeast reproductive potential and extended its reproductive lifespan. These changes may be a result of the reduced mitochondrial membrane potential and decreased ATP content in the yeast cells. However, due to reduction of the post-reproductive lifespan, L-carnosine did not have an influence on the total lifespan of yeast. In conclusion, L-carnosine does not extend the total lifespan of S. cerevisiae but rather it increases the yeast's reproductive capacity by increasing the number of daughter cells produced.

Effect of Carnosine in Experimental Arthritis and on Primary Culture Chondrocytes

Carnosine's (CARN) anti-inflammatory potential in autoimmune diseases has been but scarcely investigated as yet. The aim of this study was to evaluate the therapeutic potential of CARN in rat adjuvant arthritis, in the model of carrageenan induced hind paw edema (CARA), and also in primary culture of chondrocytes under H₂O₂ injury. The experiments were done on healthy animals, arthritic animals, and arthritic animals with oral administration of CARN in a daily dose of 150 mg/kg b.w. during 28 days as well as animals with CARA treated by a single administration of CARN in the same dose. CARN beneficially affected hind paw volume and changes in body weight on day 14 and reduced hind paw swelling in CARA. Markers of oxidative stress in plasma and brain (malondialdehyde, 4-hydroxynonenal, protein carbonyls, and lag time of lipid peroxidation) and also activity of gamma-glutamyltransferase were significantly corrected by CARN. CARN also reduced IL-1alpha in plasma. Suppression of intracellular oxidant levels was also observed in chondrocytes pretreated with CARN. Our results obtained on two animal models showed that CARN has systemic anti-inflammatory activity and protected rat brain and chondrocytes from oxidative stress. This finding suggests that CARN might be beneficial for treatment of arthritic diseases.

β-Alanine supplementation and military performance

During sustained high-intensity military training or simulated combat exercises, significant decreases in physical performance measures are often seen. The use of dietary supplements is becoming increasingly popular among military personnel, with more than half of the US soldiers deployed or garrisoned reported to using dietary supplements. β-Alanine is a popular supplement used primarily by strength and power athletes to enhance performance, as well as training aimed at improving muscle growth, strength and power. However, there is limited research examining the efficacy of β-alanine in soldiers conducting operationally relevant tasks. The gains brought about by β-alanine use by selected competitive athletes appears to be relevant also for certain physiological demands common to military personnel during part of their training program. Medical and health personnel within the military are expected to extrapolate and implement relevant knowledge and doctrine from research performed on other population groups. The evidence supporting the use of β-alanine in competitive and recreational athletic populations suggests that similar benefits would also be observed among tactical athletes. However, recent studies in military personnel have provided direct evidence supporting the use of β-alanine supplementation for enhancing combat-specific performance. This appears to be most relevant for high-intensity activities lasting 60-300 s. Further, limited evidence has recently been presented suggesting that β-alanine supplementation may enhance cognitive function and promote resiliency during highly stressful situations.

Possible Benefit of Dietary Carnosine towards Depressive Disorders

Many stress-related and depressive disorders have been shown to be associated with one or more of the following; shortened telomeres, raised cortisol levels and increased susceptibility to age-related dysfunction. It is suggested here that insufficient availability of the neurological peptide, carnosine, may provide a biochemical link between stress- and depression-associated phenomena: there is evidence that carnosine can enhance cortisol metabolism, suppress telomere shortening and exert anti-aging activity in model systems. Dietary supplementation with carnosine has been shown to suppress stress in animals, and improve behaviour, cognition and well-being in human subjects. It is therefore proposed that the therapeutic potential of carnosine dietary supplementation towards stress-related and depressive disorders should be examined.

β-Alanine ingestion increases muscle carnosine content and combat specific performance in soldiers

The purpose of this study was to examine the effect of β-alanine (BA) ingestion on tissue carnosine levels and the impact such changes would have on combat specific activity. Eighteen soldiers (19.9 ± 0.8 year) from an elite combat unit were randomly assigned to either a BA or placebo (PL) group. Before and following a 30-day supplementation period carnosine content of the gastrocnemius muscle and brain was determined by proton magnetic resonance spectroscopy. During each testing session, participants performed military relevant tasks that included a 2.5 km run, a 1-min sprint, 50-m casualty carry, repeated 30-m sprints with target shooting, and a 2-min serial subtraction test (SST) to assess cognitive function under stressful conditions. A significant elevation (p = 0.048) in muscle carnosine content was noted in BA compared to PL. Changes in muscle carnosine content was correlated to changes in fatigue rate (r = 0.633, p = 0.06). No changes (p = 0.607) were observed in brain carnosine content. Following supplementation, no differences were noted in 2.5 km run, 1-min sprint, repeated sprint, or marksmanship performance, but participants in BA significantly (p = 0.044) improved their time for the 50-m casualty carry and increased their performance (p = 0.022) in the SST compared to PL. In summary, 30-days of BA ingestion can increase muscle carnosine content and improve aspects of military specific performance. Although cognitive performance was significantly greater in participants consuming BA compared to placebo, current study methods were unable to detect any change in brain carnosine levels, thus, the precise mechanism underlying these effects remains elusive.

Sex specific association between carnosinase gene CNDP1 and cardiovascular mortality in patients with type 2 diabetes (ZODIAC-22)

INTRODUCTION

Homozygosity for a 5-leucine repeat (5L-5L) in the carnosinase gene (CNDP1) has been associated with a reduced prevalence of diabetic nephropathy in cross-sectional studies in patients with type 2 diabetes, particularly in women. Prospective studies on mortality are not available. This study investigated whether 5L-5L was associated with mortality and progression of renal function loss and to what extent this effect is modified by sex.

METHODS

In a prospective cohort of patients with type 2 diabetes, a Cox proportional hazard model was used to compare 5L-5L with other genotypes regarding (cardiovascular) mortality. Renal function slopes were obtained by within-individual linear regression of the estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease (MDRD) equation, and were compared between 5L-5L and other genotypes.

RESULTS

871 patients were included (38% with 5L-5L). After 9.5 years of follow-up, hazards ratios (HR) for all-cause and cardiovascular mortality in 5L-5L versus other genotypes were 1.09 [95% confidence interval (CI) 0.88-1.36] and 1.12 (95% CI 0.79-1.58), respectively. There was a significant interaction between CNDP1 and sex for the association with cardiovascular mortality (p = 0.01), not for all-cause mortality (p = 0.32). Adjusted HR in 5L-5L for cardiovascular mortality was 0.69 (95% CI 0.39-1.23) in men and 1.77 (95% CI 1.12-2.81) in women. The slopes of eGFR-MDRD did not significantly differ between 5L-5L and other genotypes.

CONCLUSIONS

The association between CNDP1 and cardiovascular mortality was sex-specific, with a higher risk in women with 5L-5L genotype. CNDP1 was not associated with all-cause mortality or change in eGFR.

β-alanine supplementation improves tactical performance but not cognitive function in combat soldiers

Background

There are no known studies that have examined β-alanine supplementation in military personnel. Considering the physiological and potential neurological effects that have been reported during sustained military operations, it appears that β-alanine supplementation may have a potential benefit in maintaining physical and cognitive performance during high-intensity military activity under stressful conditions. The purpose of this study was to examine the effect of 28 days of β-alanine ingestion in military personnel while fatigued on physical and cognitive performance.

Methods

Twenty soldiers (20.1 ± 0.9 years) from an elite combat unit were randomly assigned to either a β-alanine (BA) or placebo (PL) group. Soldiers were involved in advanced military training, including combat skill development, navigational training, self-defense/hand-to-hand combat and conditioning. All participants performed a 4-km run, 5-countermovement jumps using a linear position transducer, 120-m sprint, a 10-shot shooting protocol with assault rifle, including overcoming a misfire, and a 2-min serial subtraction test to assess cognitive function before (Pre) and after (Post) 28 days of supplementation.

Results

The training routine resulted in significant increases in 4-km run time for both groups, but no between group differences were seen (p = 0.597). Peak jump power at Post was greater for BA than PL (p = 0.034), while mean jump power for BA at Post was 10.2% greater (p = 0.139) than PL. BA had a significantly greater (p = 0.012) number of shots on target at Post (8.2 ± 1.0) than PL (6.5 ± 2.1), and their target engagement speed at Post was also significantly faster (p = 0.039). No difference in serial subtraction performance was seen between the groups (p = 0.844).

Conclusion

Results of this study indicate that 4-weeks of β-alanine ingestion in young, healthy soldiers did not impact cognitive performance, but did enhance power performance, marksmanship and target engagement speed from pre-ingestion levels.

Physiology and pathophysiology of carnosine

Carnosine (β-alanyl-l-histidine) was discovered in 1900 as an abundant non-protein nitrogen-containing compound of meat. The dipeptide is not only found in skeletal muscle, but also in other excitable tissues. Most animals, except humans, also possess a methylated variant of carnosine, either anserine or ophidine/balenine, collectively called the histidine-containing dipeptides. This review aims to decipher the physiological roles of carnosine, based on its biochemical properties. The latter include pH-buffering, metal-ion chelation, and antioxidant capacity as well as the capacity to protect against formation of advanced glycation and lipoxidation end-products. For these reasons, the therapeutic potential of carnosine supplementation has been tested in numerous diseases in which ischemic or oxidative stress are involved. For several pathologies, such as diabetes and its complications, ocular disease, aging, and neurological disorders, promising preclinical and clinical results have been obtained. Also the pathophysiological relevance of serum carnosinase, the enzyme actively degrading carnosine into l-histidine and β-alanine, is discussed. The carnosine system has evolved as a pluripotent solution to a number of homeostatic challenges. l-Histidine, and more specifically its imidazole moiety, appears to be the prime bioactive component, whereas β-alanine is mainly regulating the synthesis of the dipeptide. This paper summarizes a century of scientific exploration on the (patho)physiological role of carnosine and related compounds. However, far more experiments in the fields of physiology and related disciplines (biology, pharmacology, genetics, molecular biology, etc.) are required to gain a full understanding of the function and applications of this intriguing molecule.

Aging risk factors and Parkinson's disease: contrasting roles of common dietary constituents

Aging is a Parkinson's disease (PD) risk factor. It is suggested here that certain dietary components may either contribute to or ameliorate PD risk. There is evidence, which indicates that excessive carbohydrate (glucose or fructose) catabolism is a cause of mitochondrial dysfunction in PD, one consequence is increased production of methylglyoxal (MG). However, other dietary components (carnosine and certain plant extracts) not only scavenge MG but can also influence some of the biochemical events (signal transduction, stress protein synthesis, glycation, and toxin generation) associated with PD pathology. As double blind, placebo-controlled carnosine supplementation studies have revealed beneficial outcomes in humans, it is suggested that MG scavengers such as carnosine be further explored for their therapeutic potential toward PD.

Beneficial effects of taurine and carnosine in experimental ischemia/reperfusion injury in testis

PURPOSE

Testicular torsion can be thought of as an ischemia/reperfusion (I/R) injury to the testis. This study aimed to investigate the effects of taurine (TAU) and carnosine (CAR), which are strong antioxidants, on experimental testicular I/R injury model.

METHODS

Male Wistar albino rats were divided into four groups with eight animals in each. A sham operation was performed in group 1. To create testicular I/R, the left testis was torsioned 720° for 2 h followed by 2 h of detorsion. Groups 2 (I/R), 3 (I/R + TAU) and 4 (I/R + CAR) received intraperitoneal saline, TAU (250 mg/kg) and CAR (250 mg/kg), respectively, 1 h before detorsion. Thiobarbituric acid reactive substances (TBARS), diene conjugate (DC), protein carbonyls (PC), nonprotein sulfhydryl (NPSH), and vitamin C levels were measured in testis tissues as well as superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities. Histopathological evaluation was also performed.

RESULTS

TBARS, DC, and PC levels were significantly increased in I/R group. TAU and CAR did not alter TBARS levels, but decreased the elevated DC and PC levels. There were no changes in testicular NPSH levels, SOD, and GPx activities in all groups; however, vitamin C significantly decreased in I/R group. CAR treatment was found to increase vitamin C levels as compared to I/R group. Histopathologically, both I/R + TAU and I/R + CAR groups showed significant increase in testicular spermatogenesis in comparison to I/R group.

CONCLUSION

Our results indicate that TAU and CAR reduces oxidative stress and may have a protective role in testicular I/R injury.

Management of the virulent influenza virus infection by oral formulation of nonhydrolized carnosine and isopeptide of carnosine attenuating proinflammatory cytokine-induced nitric oxide production

Inducible nitric oxide synthase (iNOS) plays an important role in mediating inflammation. In our studies, we found that iNOS-derived NO was significantly increased in the serum samples of 150 patients infected with influenza A virus in comparison with samples of 140 healthy individuals. In human lung epithelial cells, infection with influenza A virus or stimulation with poly(I:C) + interferon-gamma resulted in increased mRNA and protein levels of both interleukin-32 and iNOS, with subsequent release of NO. Activated macrophages are also a source of nitric oxide (NO), which is largely produced by iNOS in response to proinflammatory cytokines. In this review article, the presented findings have many important implications for understanding the Influenza A (H1N1) viral pathogenesis, prevention, and treatment. The direct viral cytotoxicity (referred cytopathic effect) is only a fraction of several types of events induced by virus infection. Nitric oxide and oxygen free radicals such as superoxide anion (O₂⁻˙) are generated markedly in influenza A (including H1N1) virus-infected host boosts, and these molecular species are identified as the potent pathogenic agents. The mutual interaction of NO with O₂⁻˙ resulting in formation of peroxynitrite is operative in the pathogenic mechanism of influenza virus pneumonia. The toxicity and reactivity of oxygen radicals, generated in excessive amounts mediate the overreaction of the host's immune response against the organs or tissues in which viruses are replicating, and this may explain the mechanism of tissue injuries observed in influenza virus infection of various types. The authors revealed the protection that carnosine and its bioavailable nonhydrolized forms provide against peroxynitrite damage and other types of viral injuries in which immunologic interactions are usually involved. Carnosine (beta-alanyl-L-histidine) shows the pharmacologic intracellular correction of NO release which might be one of the important factors of natural immunity in controlling the initial stages of influenza A virus infection (inhibition of virus replication) and virus-induced regulation of cytokine gene expression. The protective effects of orally applied nonhydrolized formulated species of carnosine include at least direct interaction with nitric oxide, inhibition of cytotoxic NO-induced proinflammatory condition, and attenuation of the effects of cytokines and chemokines that can exert profound effects on inflammatory cells. These data are consistent with the hypothesis that natural products, such as chicken soup and chicken breast extracts rich in carnosine and its derivative anserine (beta-alanyl-1-methyl-L-histidine) could contribute to the pathogenesis and prevention of influenza virus infections and cold but have a limitation due to susceptibility to enzymatic hydrolysis of dipeptides with serum carnosinase and urine excretion after oral ingestion of a commercial chicken extract. The developed and patented by the authors formulations of nonhydrolized in digestive tract and blood natural carnosine peptide and isopeptide (gamma-glutamyl-carnosine) products have a promise in the Influenza A (H1N1) virus infection disease control and prevention.

Cellular stress responses, hormetic phytochemicals and vitagenes in aging and longevity

Modulation of endogenous cellular defense mechanisms represents an innovative approach to therapeutic intervention in diseases causing chronic tissue damage, such as in neurodegeneration. This paper introduces the emerging role of exogenous molecules in hormetic-based neuroprotection and the mitochondrial redox signaling concept of hormesis and its applications to the field of neuroprotection and longevity. Maintenance of optimal long-term health conditions is accomplished by a complex network of longevity assurance processes that are controlled by vitagenes, a group of genes involved in preserving cellular homeostasis during stressful conditions. Vitagenes encode for heat shock proteins (Hsp) Hsp32, Hsp70, the thioredoxin and the sirtuin protein systems. Dietary antioxidants, such as polyphenols and L-carnitine/acetyl-L-carnitine, have recently been demonstrated to be neuroprotective through the activation of hormetic pathways, including vitagenes. Hormesis provides the central underpinning of neuroprotective responses, providing a framework for explaining the common quantitative features of their dose response relationships, their mechanistic foundations, their relationship to the concept of biological plasticity as well as providing a key insight for improving the accuracy of the therapeutic dose of pharmaceutical agents within the highly heterogeneous human population. This paper describes in mechanistic detail how hormetic dose responses are mediated for endogenous cellular defense pathways including sirtuin, Nrfs and related pathways that integrate adaptive stress responses in the prevention of neurodegenerative diseases. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.

Zinc deficiency or excess within the physiological range increases genome instability and cytotoxicity, respectively, in human oral keratinocyte cells

Zinc (Zn) is an essential component of Zn-finger proteins and acts as a cofactor for enzymes required for cellular metabolism and in the maintenance of DNA integrity. The study investigated the genotoxic and cytotoxic effects of Zn deficiency or excess in a primary human oral keratinocyte cell line and determined the optimal concentration of two Zn compounds (Zn Sulphate (ZnSO(4)) and Zn Carnosine (ZnC)) to minimise DNA damage. Zn-deficient medium (0 μM) was produced using Chelex treatment, and the two Zn compounds ZnSO(4) and ZnC were tested at concentrations of 0.0, 0.4, 4.0, 16.0, 32.0 and 100.0 μM. Cell viability was decreased in Zn-depleted cells (0 μM) as well as at 32 μM and 100 μM for both Zn compounds (P < 0.0001) as measured via the MTT assay. DNA strand breaks, as measured by the comet assay, were found to be increased in Zn-depleted cells compared with the other treatment groups (P < 0.05). The Cytokinesis Block Micronucleus Cytome assay showed a significant increase in the frequency of both apoptotic and necrotic cells under Zn-deficient conditions (P < 0.05). Furthermore, elevated frequencies of micronuclei (MNi), nucleoplasmic bridges (NPBs) and nuclear buds (NBuds) were observed at 0 and 0.4 μM Zn, whereas these biomarkers were minimised for both Zn compounds at 4 and 16 μM Zn (P < 0.05), suggesting these concentrations are optimal to maintain genome stability. Expression of PARP, p53 and OGG1 measured by western blotting was increased in Zn-depleted cells indicating that DNA repair mechanisms are activated. These results suggest that maintaining Zn concentrations within the range of 4-16 μM is essential for DNA damage prevention in cultured human oral keratinocytes.

Effects of dietary supplementation of carnosine on mitochondrial dysfunction, amyloid pathology, and cognitive deficits in 3xTg-AD mice

Background

The pathogenic road map leading to Alzheimer's disease (AD) is still not completely understood; however, a large body of studies in the last few years supports the idea that beside the classic hallmarks of the disease, namely the accumulation of amyloid-β (Aβ) and neurofibrillary tangles, other factors significantly contribute to the initiation and the progression of the disease. Among them, mitochondria failure, an unbalanced neuronal redox state, and the dyshomeostasis of endogenous metals like copper, iron, and zinc have all been reported to play an important role in exacerbating AD pathology. Given these factors, the endogenous peptide carnosine may be potentially beneficial in the treatment of AD because of its free-radical scavenger and metal chelating properties.

Methodology

In this study, we explored the effect of L-carnosine supplementation in the 3xTg-AD mouse, an animal model of AD that shows both Aβ- and tau-dependent pathology.

Principal Findings

We found that carnosine supplementation in 3xTg-AD mice promotes a strong reduction in the hippocampal intraneuronal accumulation of Aβ and completely rescues AD and aging-related mitochondrial dysfunctions. No effects were found on tau pathology and we only observed a trend toward the amelioration of cognitive deficits.

Conclusions and Significance

Our data indicate that carnosine can be part of a combined therapeutic approach for the treatment of AD.

The effect of zinc sulphate and zinc carnosine on genome stability and cytotoxicity in the WIL2-NS human lymphoblastoid cell line

Zinc (Zn) is an essential cofactor required by numerous enzymes that are essential for cell metabolism and the maintenance of DNA integrity. We investigated the effect of Zn deficiency or excess on genomic instability events and determined the optimal concentration of two Zn compounds that minimize DNA-damage events. The effects of Zn sulphate (ZnSO(4)) and Zn carnosine (ZnC) on cell proliferation were investigated in the WIL2-NS human lymphoblastoid cell line. DNA damage was determined by the use of both the comet assay and the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay. Zn-deficient medium (0μM) was produced using Chelex treatment, and the two Zn compounds (i.e. ZnSO(4) and ZnC) were tested at concentrations of 0.0, 0.4, 4.0, 16.0, 32.0 and 100.0μM. Results from an MTT assay showed that cell growth and viability were decreased in Zn-depleted cells (0μM) as well as at 32μM and 100μM for both Zn compounds (P<0.0001). DNA strand-breaks, as measured by the comet assay, were found to be increased in Zn-depleted cells compared with the other treatment groups (P<0.05). The CBMN-Cyt assay showed a significant increase in the frequency of both apoptotic and necrotic cells under Zn-deficient conditions (P<0.0001). Elevated frequencies of micronuclei (MNi), nucleoplasmic bridges (NPBs) and nuclear buds (NBuds) were induced in Zn-depleted cells (P<0.0001), whereas genome damage was reduced in supplemented cultures for both Zn compounds at 4μM and 16μM, possibly suggesting that these concentrations may be optimal for genome stability. The potential protective effect of ZnSO(4) and ZnC was also investigated following exposure to 1.0Gy γ-radiation. Culture in medium containing these compounds at 4-32μM prior to irradiation displayed significantly reduced frequencies of MNi, NPBs and NBuds compared with cells maintained in 0μM medium (P<0.0001). Expression of γ-H2AX and 8-oxoguanine glycosylase measured by western blotting was increased in Zn-depleted cells. These results suggest that Zn plays important role in genomic stability and that the optimal Zn concentration-range for prevention of DNA damage and cytotoxicity in vitro lies between 4 and 16μM.

A polymorphism in the gene encoding carnosinase (CNDP1) as a predictor of mortality and progression from nephropathy to end-stage renal disease in type 1 diabetes mellitus

AIMS/HYPOTHESIS

Homozygosity for a five leucine repeat (5L-5L) in the carnosinase gene (CNDP1) has been found to be cross-sectionally associated with a low frequency of diabetic nephropathy (DN), mainly in type 2 diabetes. We prospectively investigated in patients with type 1 diabetes whether: (1) 5L-5L is associated with mortality; (2) there is an interaction of 5L-5L with DN or sex for prediction of mortality; and (3) 5L-5L is associated with progression to end-stage renal disease (ESRD).

METHODS

In this prospective study in white European patients with type 1 diabetes, individuals with DN were defined by persistent albuminuria ≥ 300 mg/24 h. Controls without nephropathy were defined by persistent (>15 years) normoalbuminuria < 30 mg/24 h. Leucine repeats were assessed with a fluorescent DNA analysis system. Onset of ESRD was defined by need to start chronic dialysis or kidney transplantation.

RESULTS

The study involved 916 patients with DN and 1,170 controls. During follow-up for 8.8 years, 107 patients (14%) with 5L-5L died compared with 182 patients (13.8%) with other genotypes (p = 0.99). There was no significant interaction of 5L-5L with DN for prediction of mortality (p = 0.57), but a trend towards interaction with sex (p = 0.08). In patients with DN, HR for ESRD in 5L-5L vs other genotypes was not constant over time, with increased risk for 5L-5L beyond 8 years of follow-up (p = 0.03).

CONCLUSIONS/INTERPRETATION

CNDP1 polymorphism was not associated with mortality, and nor was there an interaction of this polymorphism with DN for prediction of mortality in patients with type 1 diabetes. CNDP1 polymorphism predicts progression to ESRD in patients with DN, but only late after baseline measurements.

The cytotoxic mechanism of malondialdehyde and protective effect of carnosine via protein cross-linking/mitochondrial dysfunction/reactive oxygen species/MAPK pathway in neurons

The accumulation of malondialdehyde (MDA), a lipid peroxidation by-product that has been used as an indicator of cellular oxidation status, is significantly increased in many neurological diseases such as brain ischemia/reperfusion, Alzheimer's disease and Parkinson's disease in vivo. In the present study, we found that MDA treatment in vitro reduced cortical neuronal viability in a time- and dose-dependent manner and induced cellular apoptosis as well as necrosis simultaneously. Furthermore, exposure to MDA led to accumulation of intracellular reactive oxygen species, dysfunction of mitochondria (denoted by the loss of mitochondrial transmembrane potential (Δψm)) and activation of JNK and ERK. Carnosine exhibited better protection against MDA-induced cell injury than antioxidant N-acetyl-cysteine (NAC) with its multi-potency, which alleviated MDA-induced protein cross-linking, Δψm decrease, reactive oxygen species burst, JNK and ERK activation. In conclusion, our results suggest that MDA induced cell injury in vitro via protein cross-linking and successive mitochondrial dysfunction, and the activation of reactive oxygen species-dependent MAPK signaling pathway. Carnosine alleviated all these alterations induced by MDA, but NAC merely inhibited Bcl-2 family-related activation of JNK and ERK. These results prompt the possibility that carnosine, but not other conventional antioxidants, can protect neurons against MDA-induced injury through decomposition of protein cross-linking toxicity and may serve as a novel agent in the treatment of neurodegenerative diseases.

Identifying and treating cognitive impairment in bipolar disorder

OBJECTIVES

The presence of cognitive deficits has become increasingly appreciated across all phases of bipolar disorder. The present review sought to identify domains of cognitive dysfunction, methods of assessment, discrimination of iatrogenic from illness-specific etiologies, and pharmacologic strategies to manage cognitive problems in patients with bipolar disorder.

METHODS

A selective literature review was performed focusing on studies of descriptive phenomenology and pharmacologic intervention (favoring randomized comparisons when existent but open trials or case reports when not) involving cognition in bipolar disorder populations, healthy volunteers, or other clinical populations. Identification was made of (i) practical strategies for clinical assessment and management of cognitive complaints, (ii) limitations of existing intervention studies, and (iii) recommendations for the design and direction of future research.

RESULTS

Cognitive deficits involving attention, executive function, and verbal memory are evident across all phases of bipolar disorder. Most existing treatment studies involve nonbipolar populations, prompting caution when extrapolating outcomes to individuals with bipolar disorder. Differentiating medication- from illness-induced cognitive dysfunction requires comprehensive assessment with an appreciation for the cognitive domains most affected by specific medications. No current pharmacotherapies substantially improve cognition in bipolar disorder, although preliminary findings suggest some potential value for adjunctive stimulants such as modafinil and novel experimental agents.

CONCLUSIONS

Circumscribed cognitive deficits may be both iatrogenic and intrinsic to bipolar disorder. Optimal management hinges on a knowledge of illness-specific cognitive domains as well as of the beneficial or adverse cognitive profiles of common psychotropic medications.