Anti-stress effects of carnosine on restraint-evoked immunocompromise in mice through spleen lymphocyte number maintenance

Carnosine/histidine-containing dipeptide supplementation improves depression and quality of life: systematic review and meta-analysis of randomized controlled trials

CONTEXT

Mental ill-health is a common and growing issue, affecting 1 in 8 individuals or 970 million people worldwide in 2019. Histidine-containing dipeptides (HCDs) have been suggested to mitigate some aspects of mental ill-health, but a quantitative synthesis of the evidence is lacking. Therefore, a systematic review and meta-analysis of randomized controlled trials was conducted.

OBJECTIVE

To summarize the evidence on the effects of HCDs on mental health outcomes.

DATA SOURCE

A systematic literature search was performed using electronic databases (Medline via Ovid, Embase via Ovid, Scopus, Google Scholar, and Cochrane) from inception to October, 2022.

DATA EXTRACTION

Two authors independently extracted data using a structured extraction format.

DATA ANALYSIS

Data analysis was performed using STATA version 17. Random-effects models were used, and heterogeneity was assessed using the I2 test. Quality appraisal was performed using the Cochrane risk-of-bias 2.0 tool and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach.

CONCLUSION

5507 studies were identified, with 20 studies fulfilling the inclusion criteria. Eighteen studies comprising 776 participants were included in the meta-analysis. HCD supplementation (anserine/carnosine, l-carnosine, β-alanine) caused a significant reduction in depression scores measured with the Becks Depression Inventory (-0.79; 95% CI: -1.24, -0.35; moderate certainty on GRADE) when compared with placebo. An increase in quality-of-life scores measured with the 36-item Short-Form survey (SF-36) (0.65; 95% CI: 0.00, 1.30) and low certainty on GRADE in HCDs (anserine/carnosine, l-carnosine, β-alanine) when compared with placebo were found. However, the rest of the outcomes did not show a significant change between HCD supplementation and placebo. Although the number of studies included in the meta-analysis was modest, a significant mean reduction was observed in depression score as well as an increase in quality-of-life score for the HCD group when compared with placebo. Most of the studies included had small sample sizes with short follow-up periods and moderate to high risk of bias, highlighting the need for further, well-designed studies to improve the evidence base.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42017075354.

Supplementation with carnosine, a food-derived bioactive dipeptide, alleviates dexamethasone-induced oxidative stress and bone impairment via the NRF2 signaling pathway

BACKGROUND

Carnosine, a natural bioactive dipeptide derived from meat muscle, possesses strong antioxidant properties. Dexamethasone, widely employed for treating various inflammatory diseases, raises concerns regarding its detrimental effects on bone health. This study aimed to investigate the protective effects of carnosine against dexamethasone-induced oxidative stress and bone impairment, along with its underlying mechanisms, utilizing chick embryos and a zebrafish model in vivo, as well as MC3T3-E1 cells in vitro.

RESULTS

Our findings revealed that carnosine effectively mitigated bone injury in dexamethasone-exposed chick embryos, accompanied by reduced oxidative stress. Further investigation demonstrated that carnosine alleviated impaired osteoblastic differentiation in MC3T3-E1 cells and zebrafish by suppressing the excessive production of reactive oxygen species (ROS) and enhancing the activity of antioxidant enzymes such as superoxide dismutase (SOD) and glutathione peroxidase (GPX). Moreover, mechanistic studies elucidated that carnosine promoted the expression and nuclear translocation of nuclear factor erythroid 2-related factor 2 (NRF2), thereby facilitating the transcription of its downstream antioxidant response elements, including heme oxyense-1 (HO-1), glutamate cysteine ligase modifier (GCLM), and glutamate cysteine ligase catalytic (GCLC) to counteract dexamethasone-induced oxidative stress.

CONCLUSION

Overall, this study underscores the potential therapeutic efficacy of carnosine in mitigating oxidative stress and bone damage induced by dexamethasone exposure, shedding light on its underlying mechanism of action by activating the NRF2 signaling pathway. © 2024 Society of Chemical Industry.

Oral Supplementation of L-Carnosine Attenuates Acute-Stress-Induced Corticosterone Release and Mitigates Anxiety in CD157 Knockout Mice

Corticosterone, an end product of the hypothalamic-pituitary-adrenal (HPA) axis, is a crucial stress hormone. A dysregulated HPA axis and corticosterone release play pivotal roles in the onset and persistence of symptoms of stress-related psychiatric disorders, such as anxiety. The intake of nutrients, probiotics, and prebiotic supplements decreases blood corticosterone levels. The dipeptide L-carnosine is composed of beta-alanine and L-histidine and is commercially available as a nutritional supplement for recovery from fatigue. L-carnosine is involved in stress-induced corticosterone responses and anxiety behaviors in rodents. Here, we assessed the effect of L-carnosine in CD157 knockout (KO) mice, a murine model of autism spectrum disorder (ASD). The uptake of L-carnosine suppressed the increase in plasma corticosterone levels in response to acute stress and attenuated anxiety-like behaviors in CD157 KO mice. These results suggest that L-carnosine supplementation may relieve anxiety by suppressing excessive stress responses in individuals with ASD.

Immunomodulatory Effects of Chicken Broth and Histidine Dipeptides on the Cyclophosphamide-Induced Immunosuppression Mouse Model

The carnosine and anserine, which represent histidine dipeptides (HD), are abundant in chicken broth (CB). HD are endogenous dipeptide that has excellent antioxidant and immunomodulatory effects. The immunomodulatory effect of CB hydrolysate (CBH) and HD in cyclophosphamide (CTX)-induced immunosuppressed mice was examined in this study. CBH and HD were given to mice via oral gavage for 15 days, accompanied by intraperitoneal CTX administration to induce immunosuppression. CBH and HD treatment were observed to reduce immune organ atrophy (p < 0.05) and stimulate the proliferation of splenic lymphocytes (p < 0.05) while improving white blood cell, immunoglobulin M (IgM), IgG, and IgA levels (p < 0.05). Moreover, CBH and HD strongly stimulated interleukin-2 (IL-2) and interferon-gamma (IFN-γ) production by up-regulating IL-2 and IFN-γ mRNA expression (p < 0.05) while inhibiting interleukin-10 (IL-10) overproduction and IL-10 mRNA expression (p < 0.05). In addition, CBH and HD prevented the inhibition of the nitric oxide (NP)/cyclic guanosine monophosphate-cyclic adenosine monophosphate (cGMP-cAMP)/protein kinase A (PKA) signaling pathway (p < 0.05). These results indicate that CBH and HD have the potential to prevent immunosuppression induced by CTX. Our data demonstrate that CBH can effectively improve the immune capacity of immunosuppressed mice similar to the same amount of purified HD, which indicates that CBH plays its role through its own HD.

Serum metabolomics identifies metabolite panels that differentiate lame dairy cows from healthy ones

INTRODUCTION

Although much is known about lameness application of metabolomics technologies to better understanding its etiology and pathogenesis is of utmost interest.

OBJECTIVES

The objective of this study was to investigate serum metabolite alterations in pre-lame, lame and post-lame dairy cows in order to identify potential screening serum metabolite biomarkers for lameness and better understand its pathobiology.

METHODS

A combination of direct injection and tandem mass spectrometry (DI-MS/MS) with a reverse-phase liquid chromatography and tandem mass spectrometry (LC-MS/MS) analysis was performed in the serum of six cases of lameness and 20 healthy control cows (CON) at - 8 and - 4 weeks prepartum, at lameness diagnosis week, and at + 4 and + 8 weeks postpartum.

RESULTS

Data indicated that pre-lame, lame, and post-lame cows experienced altered concentrations of multiple metabolites. It is interesting to note that throughout the 16-weeks of the study, 7 serum metabolites [e.g., diacyl-phosphatidylcholine (PC aa) C30:0, phosphatidylcholine acyl-alkyl (PC ae) C40:2, sphingomyelin (SM) (OH) C14:1, SM C18:0, isoleucine (Ile), leucine (Leu), and lysine (Lys)] differentiated CON cows from the lame ones. Furthermore, 4 metabolic pathways (i.e., Lys degradation, biotin metabolism, tryptophan (Trp) metabolism, and valine [(Val)-Leu-Ile degradation) were altered in cows with lameness during the onset and progression of the disease.

CONCLUSION

Multiple metabolite and pathway alterations were identified in the serum of pre-lame, lame, and post-lame cows that through light into the pathobiology of the disease and that can be used as potential biomarker sets that can predict the risk of lameness in dairy cows.

Disturbed Yin-Yang balance: stress increases the susceptibility to primary and recurrent infections of herpes simplex virus type 1

Herpes simplex virus type 1 (HSV-1), a neurotropic herpes virus, is able to establish a lifelong latent infection in the human host. Following primary replication in mucosal epithelial cells, the virus can enter sensory neurons innervating peripheral tissues via nerve termini. The viral genome is then transported to the nucleus where it can be maintained without producing infectious progeny, and thus latency is established in the cell. Yin–Yang balance is an essential concept in traditional Chinese medicine (TCM) theory. Yin represents stable and inhibitory factors, and Yang represents the active and aggressive factors. When the organism is exposed to stress, especially psychological stress caused by emotional stimulation, the Yin–Yang balance is disturbed and the virus can re-engage in productive replication, resulting in recurrent diseases. Therefore, a better understanding of the stress-induced susceptibility to HSV-1 primary infection and reactivation is needed and will provide helpful insights into the effective control and treatment of HSV-1. Here we reviewed the recent advances in the studies of HSV-1 susceptibility, latency and reactivation. We included mechanisms involved in primary infection and the regulation of latency and described how stress-induced changes increase the susceptibility to primary and recurrent infections.

Resveratrol Protects against Restraint Stress Effects on Stomach and Spleen in Adult Male Mice

The objectives were to investigate whether restraint stress (which is known as a mixture of psychologic and physical stress) exerts negative effects on the stomach and spleen, and whether the phenolic compound resveratrol (RES) exerts any protective roles. Fifty adult male mice were divided into five groups, with 10 mice per group as follows: control (C), restraint stress (RS), RS with vehicle (RS + V), RS with 2 mg/kg of resveratrol (RS + 2 mg RES), and RS with 20 mg/kg of resveratrol (RS + 20 mg RES). Mice were restrained in conical centrifuge tubes for 4 h daily to establish the RS model. RS + 2 mg RES, RS + 20 mg RES, and RS + V groups were given an oral dose of resveratrol or vehicle for 15 consecutive days, while the control group was not exposed to restraint stress. Herein, we showed that restraint stress decreased body weight and food and water consumption in stressed groups RS and RS + V compared to controls, while the groups treated with resveratrol showed improvements. Moreover, restraint stress caused acute damage to the morphology of gastric cells and reduced the quantitative distribution of parietal cells along with their decreased size and diameter, pointing to gastritis or ulcer. Furthermore, the antibody against the apoptosis-inducing factor (AIF) was highly attached in the RS groups. Splenic size, weight, and length were also greatly augmented in the stressed groups compared to the controls, while these phenomena were not observed in the RS + 2 mg RES group. Our findings proved significant ameliorating effects of resveratrol against restraint stress in adult male mice.

Carnosine improves diabetic retinopathy via the MAPK/ERK pathway

Diabetic retinopathy (DR) is one of the most common causes of blindness in developed countries. Due to its asymptomatic onset and progressive disease course, DR is typically diagnosed at a late stage when treatment options are limited and therefore often results in irreversible blindness. Studies have demonstrated that carnosine may prevent and treat DR. In a previous study, the positive effect of carnosine on DR was determined and it was revealed that there may be an association between carnosine and the mitogen-activated protein kinase (MAPK)/extracellular signal related kinase (ERK) signaling pathway. To assess the interaction between carnosine and the MAPK/ERK signaling pathway, changes in PKC, ERK and p-ERK expression was assessed in diabetic rats following treatment with carnosine, PD98059 or U46619 via reverse transcription-quantitative polymerase chain reaction and western blotting. The results demonstrated that the expression of ERK and p-ERK were significantly suppressed following treatment with carnosine, but no significant effect on the expression of PKC was identified, which indicates that suppressing the activation of the MAPK/ERK signaling pathway may serve an important role in carnosine-induced DR prevention and treatment.

Psychological Stress and Mitochondria: A Systematic Review

OBJECTIVE

Mitochondria are multifunctional life-sustaining organelles that represent a potential intersection point between psychosocial experiences and biological stress responses. This article provides a systematic review of the effects of psychological stress on mitochondrial structure and function.

METHODS

A systematic review of the literature investigating the effects of psychological stress on mitochondrial function was conducted. The review focused on experimentally controlled studies allowing us to draw causal inference about the effect of induced psychological stress on mitochondria.

RESULTS

A total of 23 studies met the inclusion criteria. All studies involved male laboratory animals, and most demonstrated that acute and chronic stressors influenced specific facets of mitochondrial function, particularly within the brain. Nineteen studies showed significant adverse effects of psychological stress on mitochondria and four found increases in function or size after stress. In humans, only six observational studies were available, none with experimental designs, and most only measured biological markers that do not directly reflect mitochondrial function, such as mitochondrial DNA copy number.

CONCLUSONS

Overall, evidence supports the notion that acute and chronic stressors influence various aspects of mitochondrial biology, and that chronic stress exposure can lead to molecular and functional recalibrations among mitochondria. Limitations of current animal and human studies are discussed. Maladaptive mitochondrial changes that characterize this subcellular state of stress are termed mitochondrial allostatic load. Prospective studies with sensitive measures of specific mitochondrial outcomes will be needed to establish the link between psychosocial stressors, emotional states, the resulting neuroendocrine and immune processes, and mitochondrial energetics relevant to mind-body research in humans.

The protective effect of the Vacha rhizome extract on chronic stress-induced immunodeficiency in rat

CONTEXT

Chronic stress is an inevitable factor in the modern day society which affects cell mediated as well as humoral immunity. There is a need to prevent stress effects with traditionally used herbs.

OBJECTIVE

The present study was undertaken to investigate the immunoprotective effect of Vacha (Acorus calamus L. Acoraceae) rhizome under stressful condition.

MATERIALS AND METHODS

Soxlet extraction of Vacha rhizome was performed with increasing polarity of solvents, i.e., petroleum ether to ethanol. The extract was concentrated by distilling off the solvent in flash evaporator and dried in desiccators. The benzene extract was found to have anti-stress property in our earlier studies and hence it was used in the present experiment. Extract was administered every day for 4 weeks orally to adult female rats prior to exposure to stress, restraint (1 h) and forced swimming exercise (15 min).

RESULTS

Vacha rhizome extract significantly prevented the stress induced reduction in total and differential leukocytes count, immunoglobulin content, bone marrow cellularity and viability, lymphocytes counts in lymphoid organs, islands of white pulp of spleen (ED₅₀ = 10 mg, p < 0.001) and a significant increase in circulating immune complexes and apoptotic index of lymphoid organs (ED₅₀ = 10 mg, p < 0.001) compared to controls.

DISCUSSION AND CONCLUSION

The present study clearly indicates that Vacha extract not only prevents stress-induced suppression of immunity and structural involution of lymphoid organs, but also boosts immunity in normal rats. Therefore, it is suggested that Vacha extract administration maintains normal immunity despite the body experiencing stress.

Does supplementation with carnosine improve cardiometabolic health and cognitive function in patients with pre-diabetes and type 2 diabetes? study protocol for a randomised, double-blind, placebo-controlled trial

INTRODUCTION

Carnosine, an over-the-counter food supplement, has a promising potential for the prevention and treatment of chronic diseases such as type 2 diabetes (T2DM), cardiovascular and neurodegenerative diseases through its anti-inflammatory, antiglycation, antioxidative and chelating effects. We have previously shown that supplementation with carnosine preserves insulin sensitivity and secretion in non-diabetic overweight and obese individuals. The effect of carnosine on cardiometabolic risk and related cognitive outcomes in patients with pre-diabetes and T2DM has thus far not been studied. We therefore aim to investigate whether supplementation with carnosine improves cardiometabolic health and cognitive function in patients with pre-diabetes and T2DM.

METHODS AND ANALYSIS

We will employ a parallel design randomised controlled trial. Fifty participants with pre-diabetes (impaired fasting glycaemia and impaired glucose tolerance) and T2DM (with HbA1c level < 8%) aged between 18 to 70 years will be randomly assigned to the intervention or control group. At baseline, participants will undergo a medical review and series of tests including anthropometric measurements (body mass index, a dual X-ray absorptiometry and peripheral quantitative computed tomography scan), an oral glucose tolerance test, cardiovascular measurements (central blood pressure, endothelial function and arterial stiffness), cognitive function, physical activity measurement, heart rate variability and liver fibroscan as well as questionnaires to assess dietary habits, sleep quality, depression and quality of life. The intervention group will receive 2 g of carnosine daily in two divided doses while the control group will receive identical placebo capsules for 14 weeks. All baseline measurements will be repeated at the end of the intervention. The change in glycaemic, cardiovascular and cognitive parameters as well as other measures will be compared between the groups.

ETHICS AND DISSEMINATION

This study is approved by the Human Research Ethics Committee of Monash Health and Monash University, Australia. The findings will be disseminated via peer-reviewed publications and conference presentations.

TRIAL REGISTRATION

NCT02917928; Pre-results.

Carnosine attenuates cyclophosphamide-induced bone marrow suppression by reducing oxidative DNA damage

Oxidative DNA damage in bone marrow cells is the main side effect of chemotherapy drugs including cyclophosphamide (CTX). However, not all antioxidants are effective in inhibiting oxidative DNA damage. In this study, we report the beneficial effect of carnosine (β-alanyl-l-histidine), a special antioxidant with acrolein-sequestering ability, on CTX-induced bone marrow cell suppression. Our results show that carnosine treatment (100 and 200 mg/kg, i.p.) significantly inhibited the generation of reactive oxygen species (ROS) and 8-hydroxy-2′-deoxyguanosine (8-oxo-dG), and decreased chromosomal abnormalities in the bone marrow cells of mice treated with CTX (20 mg/kg, i.v., 24 h). Furthermore, carnosine evidently mitigated CTX-induced G2/M arrest in murine bone marrow cells, accompanied by reduced ratios of p-Chk1/Chk1 and p-p53/p53 as well as decreased p21 expression. In addition, cell apoptosis caused by CTX was also suppressed by carnosine treatment, as assessed by decreased TUNEL-positive cell counts, down-regulated expressions of Bax and Cyt c, and reduced ratios of cleaved Caspase-3/Caspase-3. These results together suggest that carnosine can protect murine bone marrow cells from CTX-induced DNA damage via its antioxidant activity.

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Bone marrow cells suppression induced by CTX is associated with the increasement of ROS and oxidative DNA damage.

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Carnosine attenuates CTX-elevated oxidative DNA damage and bone marrow cells suppression.

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Favorable prospects of clinical applications for carnosine in combination with CTX.

New insights into the effects and mechanism of a classic traditional Chinese medicinal formula on influenza prevention

BACKGROUND

KangBingDu (KBD) is a classic traditional Chinese medicinal formula widely used to treat influenza. However, little information is available from controlled studies regarding the anti-influenza pharmacological activities of KBD and its underlying mechanisms, at least partly due to the lack of appropriate study models.

PURPOSE

We hypothesized that KBD might provide a protection against influenza infection by reducing the host's susceptibility to viruses. To prove it, mouse restraint stress model was employed.

METHODS

Mice were restricted and infected with influenza virus. KBD (13 and 26mg/kg/d) was orally administrated to mice from the first day of restraint stress and lasted for 7 days (twice a day). Mice were monitored daily for morbidity, symptom severity, and mortality for 21 days. The histopathologic changes were examined. For the study of mechanisms of action, we investigated whether KBD could promote mitochondria antiviral signaling protein (MAVS)-mediated antiviral signal and inhibit nuclear factor-kappa B (NF-κB)-mediated inflammation response.

RESULTS

KBD significantly decreased the susceptibility of restraint mice to influenza virus, as evidenced by lowered mortality, attenuated inflammation and reduced viral replications in lungs. Further results revealed that KBD elevated the protein expression of MAVS, which subsequently increased the IFN-β and IFITM3 protein levels, thereby helping to fight viral infections. Finally, we identified that (R,S)-goitrin, mangiferin, forsythin and forsythoside A were effective components in KBD against influenza viral infections.

CONCLUSION

KBD can reduce the susceptibility to influenza virus via mitochondrial antiviral signaling.

Aluminum chloride induced splenic lymphocytes apoptosis through NF-κB inhibition

This research investigated the relationship between lymphocytes apoptosis, hypothalamic-pituitary-adrenal (HPA) axis and NF-κB in AlCl3-treated rats. Eighty Wistar rats were orally exposed to 0 (control group, CG), 0.4 mg/mL (low-dose group, LG), 0.8 mg/mL (mid-dose group, MG) and 1.6 mg/mL (high-dose group, HG) AlCl3 for 90 days, respectively. A variety of measurements were taken including lymphocyte apoptosis index, serum corticotropin-releasing hormone (CRH), adrenocorticotrophic hormone (ACTH) and glucocorticoids (GCs) contents, GC receptors (GCR) and NF-κB mRNA and nuclear protein expressions, caspase 3 and 9 mRNA expressions and activities. The results showed that in the AlCl3-treated rats serum CRH, ACTH and GCs contents, lymphocyte GC receptors (GCR) mRNA and nuclear protein expressions, caspase 3 and 9 mRNA expressions and activities increased, while Bcl-2/Bax ratio and NF-κB mRNA and nuclear protein expressions decreased compared with the CG. Furthermore GCR and NF-κB nuclear protein expressions were negatively correlated. And NF-κB mRNA expression was positively correlated with that of Bcl-2, but negatively correlated with that of Bax in AlCl3-treated rats. These findings indicated that AlCl3 activated HPA axis, then induced splenic lymphocytes apoptosis through NF-κB inhibition.

A SIRT3/AMPK/autophagy network orchestrates the protective effects of trans-resveratrol in stressed peritoneal macrophages and RAW 264.7 macrophages

Resveratrol gains a great interest for its strong antioxidant properties, while the molecular mechanisms underlie the beneficial effects on psychosocial stress remain controversial. In this study, we demonstrated that resveratrol protected peritoneal macrophages and RAW 264.7 cells from stress-induced decrease in the total cell count, phagocytic capability, reactive oxygen species generation, monodansylcadaverine and mitochondrial membrane potential in stressed mice. Resveratrol promoted stress-induced autophagy in both models. Modulation of autophagy by rapamycin or 3-methyladenine regulated the protective effect of resveratrol, suggesting a role of autophagy in the protective mechanisms of resveratrol. The comparison studies revealed that distinct mechanisms were implicated in the protective effect of resveratrol and other antioxidants (vitamin C and edaravone). Resveratrol promoted autophagy via upregulating SIRT3 expression and phosphorylation of AMP-activated protein kinase (AMPK). Knockdown of SIRT3 resulted in decreased autophagy and abolished protective effect of resveratrol. SIRT1 was also involved in the protective mechanism of resveratrol, although its effect on autophagy was unnoticeable. Pharmacological manipulation of autophagy modulated the effects of resveratrol on SIRT3 and AMPK, revealing the engagement of a positive feedback loop. In sharp contrast, vitamin C and edaravone effectively protected macrophages from stress-induced cytotoxicity, accompanied by downregulated SIRT3 expression and AMPK phosphorylation, and decreased level of autophagy response. Taken together, we conclude that a SIRT3/AMPK/autophagy network orchestrates in the protective effect of resveratrol in macrophages.

AlCl3 induces lymphocyte apoptosis in rats through the mitochondria-caspase dependent pathway

To investigate apoptosis mechanisms in lymphocytes induced by aluminum trichloride (AlCl3) through the mitochondria-caspase dependent pathway, the spleen lymphocytes of rats were cultured with RPMI-1640 medium and exposed to AlCl3·6H2O in the final concentrations of 0 (control group, CG), 0.3 (low-dose group, LG), 0.6 (mid-dose group, MG), and 1.2 (high-dose group, HG) mmol·L(-1) for 24 h, respectively. Mitochondrial transmembrane potential (ΔΨm), cytochrome C (Cyt C) protein expression in cytoplasm, Caspase-3 and Caspase-9 activity, Bcl-2, Bax, Caspase-3 and Caspase-9 mRNA expressions, DNA ladder and lymphocytes apoptosis index were detected. The results showed that Cyt C protein expression in cytoplasm, Caspase-3 and Caspase-9 activity, Bcl-2, Bax, Caspase-3 and Caspase-9 mRNA expressions, the ratio of Bcl-2 and Bax mRNA expression, lymphocytes apoptosis index increased, while ΔΨm decreased in the AlCl3-treated groups compared with those in CG. The results indicate that AlCl3 induces lymphocyte apoptosis in rats through the mitochondria-caspase dependent pathway.

Physiological and therapeutic effects of carnosine on cardiometabolic risk and disease

Obesity, type 2 diabetes (T2DM) and cardiovascular disease (CVD) are the most common preventable causes of morbidity and mortality worldwide. They represent major public health threat to our society. Increasing prevalence of obesity and T2DM contributes to escalating morbidity and mortality from CVD and stroke. Carnosine (β-alanyl-L-histidine) is a dipeptide with anti-inflammatory, antioxidant, anti-glycation, anti-ischaemic and chelating roles and is available as an over-the-counter food supplement. Animal evidence suggests that carnosine may offer many promising therapeutic benefits for multiple chronic diseases due to these properties. Carnosine, traditionally used in exercise physiology to increase exercise performance, has potential preventative and therapeutic benefits in obesity, insulin resistance, T2DM and diabetic microvascular and macrovascular complications (CVD and stroke) as well as number of neurological and mental health conditions. However, relatively little evidence is available in humans. Thus, future studies should focus on well-designed clinical trials to confirm or refute a potential role of carnosine in the prevention and treatment of chronic diseases in humans, in addition to advancing knowledge from the basic science and animal studies.

Effects of long-term chronic stress on the lymphoid organs and blood leukocytes of the rat (Rattus norvegicus)

Exposure of adult female rats (Rattus norvegicus (Berkenhout,1769)) to restraint (1 h) and after a gap of 4 h to forced swimming exercise for 15 min daily for 12 weeks resulted in a significant decrease in (i) weight of the body and lymphoid organs (spleen, thymus, and axillary lymph node), (ii) counts of total leukocytes and their subpopulation (lymphocytes, neutrophils, monocytes, eosinophils, and basophils), and (iii) healthy cells of all lymphoid organs and a significant increase in the count of apoptotic cells in all the lymphoid organs. One month after cessation of exposure to stressors (recovery group), all the parameters did not significantly differ from stress-group rats. The results may indicate that either deleterious effects of long-term chronic exposure to stress are not reversible or the 4-week recovery period is not sufficient to restore normalcy.

Carnosine and Related Peptides: Therapeutic Potential in Age-Related Disorders

Imidazole dipeptides (ID), such as carnosine (β-alanyl-L-histidine), are compounds widely distributed in excitable tissues of vertebrates. ID are also endowed of several biochemical properties in biological tissues, including antioxidant, bivalent metal ion chelating, proton buffering, and carbonyl scavenger activities. Furthermore, remarkable biological effects have been assigned to such compounds in age-related human disorders and in patients whose activity of serum carnosinase is deficient or undetectable. Nevertheless, the precise biological role of ID is still to be unraveled. In the present review we shall discuss some evidences from clinical and basic studies for the utilization of ID as a drug therapy for age-related human disorders.

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.

Effect of kumquat (Fortunella crassifolia) pericarp on natural killer cell activity in vitro and in vivo

Natural killer (NK) cells play a key role in innate immune defense against infectious disease and cancer. A reduction of NK activity is likely to be associated with increased risk of these types of disease. In this study, we investigate the activation potential of kumquat pericarp acetone fraction (KP-AF) on NK cells. It is shown to significantly increase IFN-γ production and NK cytotoxic activity in human KHYG-1 NK cells. Moreover, oral administration of KP-AF significantly improves both suppressed plasma IFN-γ levels and NK cytotoxic activity per splenocyte in restraint-stressed mice. These results indicate that raw kumquat pericarp activates NK cells in vitro and in vivo. To identify the active constituents, we also examined IFN-γ production on KHYG-1 cells by the predicted active components. Only β-cryptoxanthin increased IFN-γ production, suggesting that NK cell activation effects of KP-AF may be caused by carotenoids such as β-cryptoxanthin.

A new mechanism of vitamin C effects on A/FM/1/47(H1N1) virus-induced pneumonia in restraint-stressed mice

It is well known that vitamin C could protect against influenza infection, but little is known about the mechanisms. This study aimed to investigate the influence and possible mechanisms of vitamin C on pneumonia induced by influenza virus in stressed mice. Results showed that restraint stress significantly increased the mortality and the severity of pneumonia in mice caused by A/FM/1/47(H1N1) virus infection, which was attenuated by oral administration of vitamin C (125 and 250 mg/kg). Moreover, vitamin C administration significantly decreased expression of susceptibility genes, including mitochondrial antiviral signaling (MAVS) and interferon regulatory factor 3 (IRF3), and increased expression of NF-κB. These work in conjunction to induce type I interferons (IFNs) and elicit innate antiviral response as key factors in RIG-I-mediated signal transduction pathway. The above effects of vitamin C were further found to relate with inhibition of excess CORT synthesis by regulating steroid hydroxylating enzymes in adrenal gland. In conclusion, the protective effects of vitamin C on influenza virus-caused pneumonia might be related to its inhibition of CORT synthesis, which reduces the susceptibility to influenza viral infection in restraint-stressed mice. These findings provide a new mechanism for the effects of vitamin C on influenza virus-induced pneumonia in restraint-stressed mice.

Effect of carnosine supplementation on apoptosis and irisin, total oxidant and antioxidants levels in the serum, liver and lung tissues in rats exposed to formaldehyde inhalation

The main objective of the study has been to show whether carnosine has positive effects on liver and lung tissues of rats exposed to a range of formaldehyde concentrations, and to explore how irisin expression and antioxidant capacity are altered in these tissues by carnosine supplementation. Sprague-Dawley type male rats were divided into 8 groups with 6 animals in each: (I) Control; no chemical supplementation); (II) sham (100mg/kg/day carnosine); (III) low dose formaldehyde (LDFA) for 5 days/week; (IV) LDFA for 5 days/week and carnosine); (V) moderate dose formaldehyde (MDFA) for 5 days/week); (VI) MDFA for 5 days/week and carnosine; (VII) high dose formaldehyde (HDFA) for 5 days/week; (VIII) and HDFA for 5 days/week and carnosine. Sham and control groups were exposed to normal air. Irisin levels of the serum, liver and lung tissue supernatants were analyzed by ELISA, while the REL method was used to determine total oxidant/antioxidant capacity. Irisin production by the tissues was detected immunohistochemically. Increasing doses of FA decreased serum/tissue irisin and total antioxidant levels relative to the controls, as also to increases in TUNEL expressions, total oxidant level, oxidant and apoptosis index. Irisin expression was detected in hepatocyte and sinusoidal cells of the liver and parenchymal cells of the lung. In conclusion, while FA exposure reduces irisin and total oxidant in the serum, liver and lung tissues in a dose-dependent manner and increases the total antioxidant capacity, carnosine supplementation reduces the oxidative stress and restores the histopathological and biochemical signs.

Carnosine: effect on aging-induced increase in brain regional monoamine oxidase-A activity

Aging is a natural biological process associated with several neurological disorders along with the biochemical changes in brain. Aim of the present investigation is to study the effect of carnosine (0.5-2.5μg/kg/day, i.t. for 21 consecutive days) on aging-induced changes in brain regional (cerebral cortex, hippocampus, hypothalamus and pons-medulla) mitochondrial monoamine oxidase-A (MAO-A) activity with its kinetic parameters. The results of the present study are: (1) The brain regional mitochondrial MAO-A activity and their kinetic parameters (except in Km of pons-medulla) were significantly increased with the increase of age (4-24 months), (2) Aging-induced increase of brain regional MAO-A activity including its Vmax were attenuated with higher dosages of carnosine (1.0-2.5μg/kg/day) and restored toward the activity that observed in young, though its lower dosage (0.5μg/kg/day) were ineffective in these brain regional MAO-A activity, (3) Carnosine at higher dosage in young rats, unlike aged rats significantly inhibited all the brain regional MAO-A activity by reducing their only Vmax excepting cerebral cortex, where Km was also significantly enhanced. These results suggest that carnosine attenuated the aging-induced increase of brain regional MAO-A activity by attenuating its kinetic parameters and restored toward the results of MAO-A activity that observed in corresponding brain regions of young rats.

Phloridzin improves lipoprotein lipase activity in stress-loaded mice via AMPK phosphorylation

Long-term stress exposure can lead to disturbed homeostasis and cause many life-style diseases. Phloridzin possesses various bioactivities, but the understanding of the effects of phloridzin on stress-related lipid metabolism disorder is limited. Our results demonstrate that phloridzin improved plasma lipoprotein lipase (LPL) activity and triglyceride metabolism in restrained mice. A decrease of angiopoietin-like protein 4 (ANGPTL4) mRNA expression and an increase of AMP-activated protein kinase (AMPK) phosphorylation were observed after phloridzin treatment. After inhibiting AMPK phosphorylation, the effects of phloridzin on the amelioration of plasma LPL activity and suppression of ANGPTL4 expression were blocked. In addition, cardiac AMPK phosphorylation, plasma LPL activity and ANGPTL4 expression were also affected by phloridzin, even if the glucocorticoid receptor was blocked. Taken together, the down-regulation of ANGPTL4 expression by phloridzin was probably via a direct activation of AMPK pathway. This discovery can provide a biochemical and nutritional basis for the use of phloridzin-containing food and beverage in daily life.

Effects of Carnosine on Cyclophosphamide-Induced Hematopoietic Suppression in Mice

Cyclophosphamide is one of the most widely used chemotherapeutic agents in treating cancers. Chemotherapy drug-induced oxidative stress produces side effects. The severity of myelosuppression increases with a high dose of cyclophosphamide. Chicken soup or chicken essence, a traditional Chinese aliment, is a popular health supplement for patients with cancers or other diseases in Asia. As a major functional component of chicken meat extract, carnosine (beta-alanyl-L-histidine), a dipeptide of the amino acids beta-alanine and histidine, has been shown to have strong antioxidant activities. In the present study, we investigated the effects of carnosine on hematopoietic suppression in mice treated with cyclophosphamide. As expected, we found that cyclophosphamide administration (with a single dose of 150 mg/kg) induced a rapid (within 24 hours) and severe hematopoietic suppression in mice. We further showed that carnosine administration (100 mg/kg/day or 200 mg/kg/day for continuous seven days) could substantially improve suppressed hematopoietic functions and accelerate the recovery of leukocyte counts, bone marrow spontaneous proliferation, colony stimulating activity (CSA) in serum, and production of endogenous cytokines such as interleukin-3 (IL-3) and stem cell factor (SCF). These results indicate that carnosine has the potential to promote the recovery from hematopoietic suppression induced by cyclophosphamide. Our data suggest that carnosine holds a potential in clinical application to minimize the side effects induced by chemotherapeutic agents such as cyclophosphamide and thus will substantially improve the overall anti-tumor effects of the standard chemotherapies.

Theacrine, a purine alkaloid obtained from Camellia assamica var. kucha, attenuates restraint stress-provoked liver damage in mice

Theacrine (1,3,7,9-tetramethyluric acid), a purine alkaloid, has proven to be beneficial in maintaining several brain functions and is being studied for potential medicinal uses in recent years. In this study, we isolated theacrine from Camellia assamica var. kucha and investigated its protective effects on liver damage induced by restraint stress in mice. Results showed that 18 h of restraint stress could induce liver damage, with an obvious increase in levels of plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST). This finding was further confirmed by hepatic pathological examination, which showed inflammatory cell infiltration and focal necrosis of hepatocytes. However, oral administration of theacrine (10, 20, 30 mg/kg for 7 consecutive days) was found to decrease plasma ALT and AST levels, reduce hepatic mRNA levels of inflammatory mediators (IL-1β, TNF-α, IL-6, and IFN-γ), and reverse the histologic damages in stressed mice. Simultaneously, theacrine also significantly decreased the content of malondialdehyde and increased oxygen radical absorbance capacity (ORAC) level in the plasma and liver of stressed mice. These results suggested that the protective effects of theacrine on stress-induced liver damage might be correlated with its antioxidative activity. The antioxidative capacity of theacrine was further evaluated by in vitro ORAC and cellular antioxidant activity assay. The results suggested that the antioxidative capacity of theacrine was not due to the direct action on free radical clearance. Moreover, the elevated activities and gene expressions of superoxide dismutase, catalase, and glutathione peroxidase, as well as the reduced activity of xanthine oxidase by theacrine treatment in stressed mice suggested that the antioxidative activity might be due to the strengthening of the antioxidant system in vivo. On the basis of the above results, theacrine is possibly a good candidate for protecting against or treating lifestyle diseases and might contribute to the study of natural products.

Stress hormones promote growth of B16-F10 melanoma metastases: an interleukin 6- and glutathione-dependent mechanism

BACKGROUND

Interleukin (IL)-6 (mainly of tumor origin) activates glutathione (GSH) release from hepatocytes and its interorgan transport to B16-F10 melanoma metastatic foci. We studied if this capacity to overproduce IL-6 is regulated by cancer cell-independent mechanisms.

METHODS

Murine B16-F10 melanoma cells were cultured, transfected with red fluorescent protein, injected i.v. into syngenic C57BL/6J mice to generate lung and liver metastases, and isolated from metastatic foci using high-performance cell sorting. Stress hormones and IL-6 levels were measured by ELISA, and CRH expression in the brain by in situ hybridization. DNA binding activity of NF-κB, CREB, AP-1, and NF-IL-6 was measured using specific transcription factor assay kits. IL-6 expression was measured by RT-PCR, and silencing was achieved by transfection of anti-IL-6 small interfering RNA. GSH was determined by HPLC. Cell death analysis was distinguished using fluorescence microscopy, TUNEL labeling, and flow cytometry techniques. Statistical analyses were performed using Student's t test.

RESULTS

Plasma levels of stress-related hormones (adrenocorticotropin hormone, corticosterone, and noradrenaline) increased, following a circadian pattern and as compared to non-tumor controls, in mice bearing B16-F10 lung or liver metastases. Corticosterone and noradrenaline, at pathophysiological levels, increased expression and secretion of IL-6 in B16-F10 cells in vitro. Corticosterone- and noradrenaline-induced transcriptional up-regulation of IL-6 gene involves changes in the DNA binding activity of nuclear factor-κB, cAMP response element-binding protein, activator protein-1, and nuclear factor for IL-6. In vivo inoculation of B16-F10 cells transfected with anti-IL-6-siRNA, treatment with a glucocorticoid receptor blocker (RU-486) or with a β-adrenoceptor blocker (propranolol), increased hepatic GSH whereas decreased plasma IL-6 levels and metastatic growth. Corticosterone, but not NORA, also induced apoptotic cell death in metastatic cells with low GSH content.

CONCLUSIONS

Our results describe an interorgan system where stress-related hormones, IL-6, and GSH coordinately regulate metastases growth.

Autophagy is involved in the effects of resveratrol on prevention of splenocyte apoptosis caused by oxidative stress in restrained mice

SCOPE

Resveratrol, a powerful natural compound for human health, is widely reported for its immunity-related beneficial properties. However, few works have studied its effect mechanism on immunity. The present study was conducted to investigate the effects of resveratrol on splenic immunity in restraint stressed mice and the mechanism was further studied as autophagy induction.

METHODS AND RESULTS

Mice were administered with resveratrol for 7 days consecutively, fixed in restraint cages for 18 h, and recovered for 12 h after the last administration. Data showed that restraint led to spleen damages, including declined spleen index, decreased CD4(+) T-cell number, increased mitochondrial oxidative damage, and apoptosis of splenocytes. Resveratrol, vitamin C (antioxidant), and rapamycin (autophagy agonist) protected spleen functions. Meanwhile, rapamycin augmented the effects of resveratrol that were abolished by chloroquine (autophagy antagonists). Further studies showed that expressions of Beclin 1 and LC3β required in autophagy development were significantly upregulated by resveratrol but not by vitamin C.

CONCLUSION

This study demonstrated that resveratrol preserved splenic immunity of restraint stressed mice. It is meaningful to find that autophagy, apart from reactive oxygen species clearance, is included as a potential mechanism via which resveratrol ameliorated the state of oxidative stress and thus protected splenocytes in mice.

Effect of carnosine on prooxidant-antioxidant balance in several tissues of rats exposed to chronic cold plus immobilization stress

In this study, we investigated the effect of L-carnosine (CAR) on prooxidant-antioxidant balance in several tissues of rats exposed to chronic stress. Both cold and immobilization stresses were applied to rats at the same time. In the stress group, rats were placed in restraint cages and kept in a cold room (+4°C) for 1 h for 21 days (5 days a week). Rats were injected with CAR (250 mg/kg, i.p.) at 30 min before stress application. Malondialdehyde, diene conjugate, protein carbonyl and nitrotyrosine levels, nonenzymatic (glutathione, vitamin E, and vitamin C), and enzymatic (catalase, superoxide dismutase and glutathione peroxidase) antioxidants were determined in the liver, heart, and brain tissues. Chronic cold plus immobilization stress was observed to affect especially the prooxidant-antioxidant status in the brain tissue of rats. This is the first report showing the beneficial effects of CAR on oxidative stress in the brain in rats exposed to stress.