Objective
Carnosine is a naturally present dipeptide in humans and an over‐the counter food additive. Evidence from animal studies supports the role for carnosine in the prevention and treatment of ...diabetes and cardiovascular disease, yet there is limited human data. This study investigated whether carnosine supplementation in individuals with overweight or obesity improves diabetes and cardiovascular risk factors.
Methods
In a double‐blind randomized pilot trial in nondiabetic individuals with overweight and obesity (age 43 ± 8 years; body mass index 31 ± 4 kg/m2), 15 individuals were randomly assigned to 2 g carnosine daily and 15 individuals to placebo for 12 weeks. Insulin sensitivity and secretion, glucose tolerance (oral glucose tolerance test), blood pressure, plasma lipid profile, skeletal muscle (1H‐MRS), and urinary carnosine levels were measured.
Results
Carnosine concentrations increased in urine after supplementation (P < 0.05). An increase in fasting insulin and insulin resistance was hampered in individuals receiving carnosine compared to placebo, and this remained significant after adjustment for age, sex, and change in body weight (P = 0.02, P = 0.04, respectively). Two‐hour glucose and insulin were both lower after carnosine supplementation compared to placebo in individuals with impaired glucose tolerance (P < 0.05).
Conclusions
These pilot intervention data suggest that carnosine supplementation may be an effective strategy for prevention of type 2 diabetes.
The human gut microbiome, an intricate ecosystem housing trillions of microorganisms within the gastrointestinal tract, holds significant importance in human health and the development of diseases. ...Recent advances in technology have allowed for an in-depth exploration of the gut microbiome, shedding light on its composition and functions. Of particular interest is the role of diet in shaping the gut microbiome, influencing its diversity, population size, and metabolic functions. Precision nutrition, a personalized approach based on individual characteristics, has shown promise in directly impacting the composition of the gut microbiome. However, to fully understand the long-term effects of specific diets and food components on the gut microbiome and to identify the variations between individuals, longitudinal studies are crucial. Additionally, precise methods for collecting dietary data, alongside the application of machine learning techniques, hold immense potential in comprehending the gut microbiome’s response to diet and providing tailored lifestyle recommendations. In this study, we investigated the complex mechanisms that govern the diverse impacts of nutrients and specific foods on the equilibrium and functioning of the individual gut microbiome of seven volunteers (four females and three males) with an average age of 40.9 ± 10.3 years, aiming at identifying potential therapeutic targets, thus making valuable contributions to the field of personalized nutrition. These findings have the potential to revolutionize the development of highly effective strategies that are tailored to individual requirements for the management and treatment of various diseases.
The gastrointestinal tract (GIT) environment has an intricate and complex nature, limiting drugs’ stability, oral bioavailability, and adsorption. Additionally, due to the drugs’ toxicity and side ...effects, renders are continuously seeking novel delivery systems. Lipid-based drug delivery vesicles have shown various loading capacities and high stability levels within the GIT. Indeed, most vesicular platforms fail to efficiently deliver drugs toward this route. Notably, the stability of vesicular constructs is different based on the different ingredients added. A low GIT stability of liposomes and niosomes and a low loading capacity of exosomes in drug delivery have been described in the literature. Bilosomes are nonionic, amphiphilic, flexible surfactant vehicles that contain bile salts for the improvement of drug and vaccine delivery. The bilosomes’ stability and plasticity in the GIT facilitate the efficient carriage of drugs (such as antimicrobial, antiparasitic, and antifungal drugs), vaccines, and bioactive compounds to treat infectious agents. Considering the intricate and harsh nature of the GIT, bilosomal formulations of oral substances have a remarkably enhanced delivery efficiency, overcoming these conditions. This review aimed to evaluate the potential of bilosomes as drug delivery platforms for antimicrobial, antiviral, antifungal, and antiparasitic GIT-associated drugs and vaccines.
chicken meat extract is a popular functional food in Asia. It is rich in the bioactive compounds carnosine and anserine, two histidine-containing dipeptides (HCD). Studies suggest that acute ...pre-exercise ingestion of chicken extracts has important applications towards exercise performance and fatigue control, but the evidence is equivocal. This study aimed to evaluate the ergogenic potential of the pre-exercise ingestion of a homemade chicken broth (CB) vs a placebo soup on a short-lasting, high-intensity cycling exercise.
fourteen men participated in this double-blind, placebo-controlled, crossover intervention study. Subjects ingested either CB, thereby receiving 46.4 mg/kg body weight of HCD, or a placebo soup (similar in taste without HCD) 40 min before an 8 min cycling time trial (TT) was performed. Venous blood samples were collected at arrival (fasted), before exercise and at 5 min recovery. Plasma HCD were measured with UPLC-MS/MS and glutathione (in red blood cells) was measured through HPLC. Capillary blood samples were collected at different timepoints before and after exercise.
a significant improvement (p = 0.033; 5.2%) of the 8 min TT mean power was observed after CB supplementation compared to placebo. Post-exercise plasma carnosine (p < 0.05) and anserine (p < 0.001) was significantly increased after CB supplementation and not following placebo. No significant effect of CB supplementation was observed either on blood glutathione levels, nor on capillary blood analysis.
oral CB supplementation improved the 8 min TT performance albeit it did not affect the acid-base balance or oxidative status parameters. Further research should unravel the potential role and mechanisms of HCD, present in CB, in this ergogenic approach.
In this study, we aimed to determine the exercise intensities eliciting the highest (FAT
) and the lowest (FAT
) fat oxidation rate in male cyclists and to compare these intensities with their ...individual aerobic (AeT) and anaerobic (AnT) thresholds, respectively. Twenty-two moderately trained male cyclists performed a 2-min stage graded exercise test until exhaustion using breath-by-breath gas analysis to determine maximal oxygen consumption (VO
). The fat oxidation rate was calculated using a stoichiometric equation, with metabolic thresholds being determined by ventilatory gas analysis. In the present group of subjects, FAT
was found at a 21.34 ± 3.64 ml·kg
·min
corresponding to 45.05 ± 7.68% VO
. AeT occurred at an exercise intensity of 22.15 ± 4.84 ml·kg
·min
, matching 46.76 ± 10.24% VO
. AnT and FAT
were located at intensities equivalent to 32.56 ± 5.52 ml·kg
·min
and 32.30 ± 5.35 ml·kg
·min
which corresponded to 68.74 ± 11.65 and 68.19 ± 11.29% VO
, respectively. The correlation between FAT
and AeT was strong (
= 0.80,
< 0.05). No statistical difference was observed between FAT
and AnT (
= 0.99,
< 0.05). The strong relationship between observed indices can be used to provide a more tailored exercise approach.
Inflammatory bowel disease (IBD) is a chronic recurrent inflammation of the gastrointestinal tract (GIT). IBD patients are susceptible to various infections such as viral infections due to the ...long-term consumption of immunosuppressive drugs and biologics. The antiviral and IBD protective traits of flavonoids have not been entirely investigated. This study objective included an overview of the protective role of flavonoids quercetin and silymarin in viral-associated IBD. Several viral agents such as cytomegalovirus (CMV), Epstein–Barr virus (EBV), varicella zoster virus (VZV) and enteric viruses can be reactivated and thus develop or exacerbate the IBD conditions or eventually facilitate the disease remission. Flavonoids such as quercetin and silymarin are non-toxic and safe bioactive compounds with remarkable anti-oxidant, anti-inflammatory and anti-viral effects. Mechanisms of anti-inflammatory and antiviral effects of silymarin and quercetin mainly include immune modulation and inhibition of caspase enzymes, viral binding and replication, RNA synthesis, viral proteases and viral assembly. In the nutraceutical sector, natural flavonoids low bioavailability and solubility necessitate the application of delivery systems to enhance their efficacy. This review study provided an updated understanding of the protective role of quercetin and silymarin against viral-associated IBD.
Carnosine (beta-alanyl-
l
-histidine) and its methylated analogue anserine are present in relevant concentrations in the omnivore human diet. Several studies reported promising therapeutic potential ...for carnosine in various rodent models of oxidative stress and inflammation-related chronic diseases. Nevertheless, the poor serum stability of carnosine in humans makes the translation of rodent models hard. Even though anserine and carnosine have similar biochemical properties, anserine has better serum stability. Despite this interesting profile, the research on anserine is scarce. The aim of this study was to explore the bioavailability and stability of synthesized anserine by (1) performing in vitro stability experiments in human plasma and molecular modelling studies and by (2) evaluating the plasma and urinary pharmacokinetic profile in healthy volunteers following different doses of anserine (4–10–20 mg/kg body weight). A bio-analytical method for measuring anserine levels was developed and validated using liquid chromatography-electrospray mass spectrometry. Both plasma (
C
MAX
: 0.54–1.10–3.12 µM) and urinary (
C
MAX
: 0.09–0.41–0.72 mg/mg creatinine) anserine increased dose-dependently following ingestion of 4–10–20 anserine mg/kg BW, respectively. The inter-individual variation in plasma anserine was mainly explained by the activity (
R
2
= 0.75) and content (
R
2
= 0.77) of the enzyme serum carnosinase-1. Compared to carnosine, a lower interaction energy of anserine with carnosinase-1 was suggested by molecular modelling studies. Conversely, the two dipeptides seems to have similar interaction with the PEPT1 transporter. It can be concluded that nutritionally relevant doses of synthesized anserine are well-absorbed and that its degradation by serum carnosinase-1 is less pronounced compared to carnosine. This makes anserine a good candidate as a more stable carnosine-analogue to attenuate chronic diseases in humans.
This laboratory study analyzes feeding preferences of a crayfish species with high invasive potentials, the red swamp crayfish Procambarus clarkii. We first conducted a series of multiple-choice ...tests among fresh plants (3 tests, one per each of three seasons, i.e. spring, summer, and autumn) and animals (1 test in summer). In the first tests, crayfish were simultaneously offered fresh pieces of seven plants of different growth forms and taxonomic groups, selected on the basis of their availability in the habitat. In the second test, the offered animals were dead earthworms, rainbow trout fry, and toad tadpoles. Then, a binary choice test was run in autumn between the most preferred plant (Urtica sp.) and earthworms. The percentages of organic C and N contents were measured for each food category using a gas-chromatography technique and the assimilation efficiency of both dry mass and organic content was assessed in a dedicated experiment. The results showed that P. clarkii is selective when offered fresh plants, consuming a relatively larger biomass of Urtica (in the three seasons examined), green algae (in spring), and Polygonum (in summer and autumn). Surprisingly, crayfish did not exhibit preference for any animal prey. Also, P. clarkii’s feeding decisions seemed not to be associated with either the availability of plants in the habitat or their occurrence in the gut contents of wild crayfish. Neither did their ingested biomass depend on the organic content or assimilation efficiency. Procambarus clarkii preferred Urtica sp. over earthworms, notwithstanding the higher nutritional value and assimilation efficiency of the latter. The above results might suggest that feeding preferences of the species often depend on factors other than nutritional value and digestibility. Future studies will analyze all the possible factors together in order to unravel the rules that govern feeding preferences in crayfish. In the case of invasive species, such knowledge will highly contribute to planning science-based actions for their containment and mitigation.
Lors de cette étude de laboratoire nous avons analysé les préférences alimentaires d’une espèce d’écrevisse ayant un fort potentiel invasif, l’écrevisse rouge des marais Procambarus clarkii. Nous avons d’abord conduit une série de tests à choix multiples avec trois plantes fraîches (3 tests, un pour les trois saisons, i.e.; printemps, été, automne) et avec des animaux (1 test). Dans les premiers tests, des morceaux frais de sept plantes de formes de croissance différentes et de groupes taxonomiques différents, choisies pour leur disponibilité dans l’habitat, ont été proposés aux écrevisses. Dans le second test, les animaux proposés étaient des vers de terre morts, des alevins de truite arc-en-ciel, et des têtards de crapaud. Ensuite un test à choix binaire a été conduit entre la plante favorite (Urtica sp.) et des vers de terre. Le pourcentage en teneur organique (C et N) a été mesuré pour chaque catégorie d’aliment en utilisant la technique par chromatographie gazeuse et l’efficacité de l’assimilation à la fois de la masse sèche et du contenu organique a été établie à l’aide d’une expérimentation spécifique. Les résultats indiquent que P. clarkii est sélective lorsqu’on lui propose des plantes fraîches, consommant une quantité relativement plus importante d’Urtica (lors des trois saisons examinées), d’algues vertes (au printemps), et de Polygonum (en été et en automne). De façon surprenante, les écrevisses n’ont manifesté de préférence pour aucune des proies animales proposées. De plus, les décisions alimentaires de P. clarkii ont semblé n’avoir aucun rapport avec la disponibilité d’aucune des plantes dans l’habitat ou leur présence dans le contenu stomacal des écrevisses sauvages. Pas plus que la biomasse ingérée n’avait de rapport avec la teneur organique ou l’efficacité de l’assimilation. Procambarus clarkii préfère Urtica sp. au vers de terre, en dépit de la valeur nutritionnelle plus élevée de ce dernier, et de sa plus grande efficacité d’assimilation. Les résultats ci-dessous pourraient suggérer que les préférences alimentaires de l’espèce dépendent souvent de facteurs autres que la valeur nutritionnelle et la digestibilité. De prochaines études analyseront tous les facteurs possibles ensemble afin de découvrir les règles qui gouvernent les préférences alimentaires des écrevisses. Dans le cas des espèces invasives, de telles connaissances contribueront grandement à la planification d’actions scientifiquement fondées, en vue du contrôle et de la réduction de leur expansion.
Key points
Using recombinant DNA technology, the present study provides the first strong and direct evidence indicating that β‐alanine is an efficient substrate for the mammalian transaminating ...enzymes 4‐aminobutyrate‐2‐oxoglutarate transaminase and alanine‐glyoxylate transaminase.
The concentration of carnosine and anserine in murine skeletal and heart muscle depends on circulating availability of β‐alanine, which is in turn controlled by degradation of β‐alanine in liver and kidney.
Chronic oral β‐alanine supplementation is a popular ergogenic strategy in sports because it can increase the intracellular carnosine concentration and subsequently improve the performance of high‐intensity exercises. The present study can partly explain why the β‐alanine supplementation protocol is so inefficient, by demonstrating that exogenous β‐alanine can be effectively routed toward oxidation.
The metabolic fate of orally ingested β‐alanine is largely unknown. Chronic β‐alanine supplementation is becoming increasingly popular for improving high‐intensity exercise performance because it is the rate‐limiting precursor of the dipeptide carnosine (β‐alanyl‐l‐histidine) in muscle. However, only a small fraction (3–6%) of the ingested β‐alanine is used for carnosine synthesis. Thus, the present study aimed to investigate the putative contribution of two β‐alanine transamination enzymes, namely 4‐aminobutyrate‐2‐oxoglutarate transaminase (GABA‐T) and alanine‐glyoxylate transaminase (AGXT2), to the homeostasis of carnosine and its methylated analogue anserine. We found that, when transfected into HEK293T cells, recombinant mouse and human GABA‐T and AGXT2 are able to transaminate β‐alanine efficiently. The reaction catalysed by GABA‐T is inhibited by vigabatrin, whereas both GABA‐T and AGXT2 activity is inhibited by aminooxyacetic acid (AOA). Both GABA‐T and AGXT2 are highly expressed in the mouse liver and kidney and the administration of the inhibitors effectively reduced their enzyme activity in liver (GABA‐T for vigabatrin; GABA‐T and AGXT2 for AOA). In vivo, injection of AOA in C57BL/6 mice placed on β‐alanine (0.1% w/v in drinking water) for 2 weeks lead to a 3‐fold increase in circulating β‐alanine levels and to significantly higher levels of carnosine and anserine in skeletal muscle and heart. By contrast, specific inhibition of GABA‐T by vigabatrin did not affect carnosine and anserine levels in either tissue. Collectively, these data demonstrate that homeostasis of carnosine and anserine in mammalian skeletal muscle and heart is controlled by circulating β‐alanine levels, which are suppressed by hepatic and renal β‐alanine transamination upon oral β‐alanine intake.
Key points
Using recombinant DNA technology, the present study provides the first strong and direct evidence indicating that β‐alanine is an efficient substrate for the mammalian transaminating enzymes 4‐aminobutyrate‐2‐oxoglutarate transaminase and alanine‐glyoxylate transaminase.
The concentration of carnosine and anserine in murine skeletal and heart muscle depends on circulating availability of β‐alanine, which is in turn controlled by degradation of β‐alanine in liver and kidney.
Chronic oral β‐alanine supplementation is a popular ergogenic strategy in sports because it can increase the intracellular carnosine concentration and subsequently improve the performance of high‐intensity exercises. The present study can partly explain why the β‐alanine supplementation protocol is so inefficient, by demonstrating that exogenous β‐alanine can be effectively routed toward oxidation.
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