Carnosine Supplementation Enhances Post Ischemic Hind Limb Revascularization

Alginate/gum arabic-based biomimetic hydrogel enriched with immobilized nerve growth factor and carnosine improves diabetic wound regeneration

Diabetic foot ulcers (DFUs) often remain untreated because they are difficult to heal, caused by reduced skin sensitivity and impaired blood vessel formation. In this study, we propose a novel approach to manage DFUs using a multifunctional hydrogel made from a combination of alginate and gum arabic. To enhance the healing properties of the hydrogel, we immobilized nerve growth factor (NGF), within specially designed mesoporous silica nanoparticles (MSN). The MSNs were then incorporated into the hydrogel along with carnosine (Car), which further improves the hydrogel's therapeutic properties. The hydrogel containing the immobilized NGF (SiNGF) could control the sustain release of NGF for >21 days, indicating that the target hydrogel (AG-Car/SiNGF) can serve as a suitable reservoir managing diabetic wound regeneration. In addition, Car was able to effectively reduce inflammation and significantly increase angiogenesis compared to the control group. Based on the histological results obtained from diabetic rats, the target hydrogel (AG-Car/SiNGF) reduced inflammation and improved re-epithelialization, angiogenesis, and collagen deposition. Specific staining also confirmed that AG-Car/SiNGF exhibited improved tissue neovascularization, transforming growth factor-beta (TGFβ) expression, and nerve neurofilament. Overall, our research suggests that this newly developed composite system holds promise as a potential treatment for non-healing diabetic wounds.

Optical Imaging Opportunities to Inspect the Nature of Cytosolic Iron Pools

The chemical nature of intracellular labile iron pools (LIPs) is described. By virtue of the kinetic lability of these pools, it is suggested that the isolation of such species by chromatography methods will not be possible, but rather mass spectrometric techniques should be adopted. Iron-sensitive fluorescent probes, which have been developed for the detection and quantification of LIP, are described, including those specifically designed to monitor cytosolic, mitochondrial, and lysosomal LIPs. The potential of near-infrared (NIR) probes for in vivo monitoring of LIP is discussed.

Carnosine as a potential therapeutic for the management of peripheral vascular disease

AIMS

To evaluate the potential role of carnosine in the management of peripheral vascular disease.

DATA SYNTHESIS

Peripheral vascular disease is growing in its burden and impact; however it is currently under researched, and there are a lack of strong, non-invasive therapeutic options for the clinicians. Carnosine is a dipeptide stored particularly in muscle and brain tissue, which exhibits a wide range of physiological activities, which may be beneficial as an adjunct treatment for peripheral vascular disease. Carnosine's strong anti-inflammatory, antioxidant and antiglycating actions may aid in the prevention of plaque formation, through protective actions on the vascular endothelium, and the inhibition of foam cells. Carnosine may also improve angiogenesis, exercise performance and vasodilatory response, while protecting from ischemic tissue injury.

CONCLUSIONS

Carnosine may have a role as an adjunct treatment for peripheral vascular disease alongside typical exercise and surgical interventions, and may be used in high risk individuals to aid in the prevention of atherogenesis.

CLINICAL RECOMMENDATION

This review identifies a beneficial role for carnosine supplementation in the management of patients with peripheral vascular disease, in conjunction with exercise and revascularization. Carnosine as a supplement is safe, and associated with a host of beneficial effects in peripheral vascular disease and its key risk factors.

Trehalose-Carnosine Prevents the Effects of Spinal Cord Injury Through Regulating Acute Inflammation and Zinc(II) Ion Homeostasis

Spinal cord injury (SCI) leads to long-term and permanent motor dysfunctions, and nervous system abnormalities. Injury to the spinal cord triggers a signaling cascade that results in activation of the inflammatory cascade, apoptosis, and Zn(II) ion homeostasis. Trehalose (Tre), a nonreducing disaccharide, and L-carnosine (Car), (β-alanyl-L-histidine), one of the endogenous histidine dipeptides have been recognized to suppress early inflammatory effects, oxidative stress and to possess neuroprotective effects. We report on the effects of the conjugation of Tre with Car (Tre-car) in reducing inflammation in in vitro and in vivo models. The in vitro study was performed using rat pheochromocytoma cells (PC12 cell line). After 24 h, Tre-car, Car, Tre, and Tre + Car mixture treatments, cells were collected and used to investigate Zn²⁺ homeostasis. The in vivo model of SCI was induced by extradural compression of the spinal cord at the T6-T8 levels. After treatments with Tre, Car and Tre-Car conjugate 1 and 6 h after SCI, spinal cord tissue was collected for analysis. In vitro results demonstrated the ionophore effect and chelating features of L-carnosine and its conjugate. In vivo, the Tre-car conjugate treatment counteracted the activation of the early inflammatory cascade, oxidative stress and apoptosis after SCI. The Tre-car conjugate stimulated neurotrophic factors release, and influenced Zn²⁺ homeostasis. We demonstrated that Tre-car, Tre and Car treatments improved tissue recovery after SCI. Tre-car decreased proinflammatory, oxidative stress mediators release, upregulated neurotrophic factors and restored Zn²⁺ homeostasis, suggesting that Tre-car may represent a promising therapeutic agent for counteracting the consequences of SCI.

Plasma Exosomal S1PR5 and CARNS1 as Potential Non-invasive Screening Biomarkers of Coronary Heart Disease

Background

Early diagnosis and treatment significantly improve the prognosis of coronary heart disease (CHD), but no convenient screening tools are available. This study aims to find potential non-invasive screening biomarkers of coronary heart disease.

Method

We performed microarray analysis to investigate the mRNA expression levels in Small extracellular vesicles (sEVs) and screen significantly differentially expressed mRNAs in CHD patients vs. non-CHD patients. We then performed quantitative real-time polymerase chain reaction (qRT-PCR) to validate the microarray results, and we calculated the correlations between expression levels and clinicopathological data. Microarray analysis identified 72 downregulated mRNAs and 31 upregulated mRNAs in CHD patients relative to non-CHD patients.

Results

From the study, we found that upregulated sphingosine-1-phosphate receptor 5 (S1PR5) and downregulated carnosine synthase 1 (CARNS1) had the most significant differences between the patient group and the control group. S1PR5 expression was correlated with diabetes, heart rate, triglycerides, total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, and fasting blood glucose (P < 0.05). CARNS1 level was correlated with uric acid (UA) (P < 0.05). Overexpressed S1PR5 and downregulated CARNS1 were independent risk factors for CHD. The area under the receiver operating characteristic curve (AUC) of S1PR5 was 0.838 for diagnosing CHD; the AUC of CARNS1 was 0.883 for non-CHD; and the AUC of S1PR5 plus CARNS1 was 0.921 for CHD.

Conclusions

Microarray analysis showed that upregulated S1PR5 and downregulated CARNS1 in sEVs have the potential to become non-invasive biomarkers for CHD screening.

Synergistic Effect of L-Carnosine and Hyaluronic Acid in Their Covalent Conjugates on the Antioxidant Abilities and the Mutual Defense against Enzymatic Degradation

Hyaluronic acid (Hy) is a natural linear polymer that is widely distributed in different organisms, especially in the articular cartilage and the synovial fluid. During tissue injury due to oxidative stress, Hy plays an important protective role. All the beneficial properties of Hy make the polymer attractive for many biomedical uses; however, the low stability and short biological half-life limit Hy application. To overcome these problems, the addition of small antioxidant molecules to Hy solution has been employed to protect the molecular integrity of Hy or delay its degradation. Carnosine (β-alanyl-L-histidine, Car) protects cells from the damage due to the reactive species derived from oxygen (ROS), nitrogen (RNS) or carbonyl groups (RCS). Car inhibits the degradation of hyaluronan induced by free radical processes in vitro but, like Hy, the potential protective action of Car is drastically hampered by the enzymatic hydrolysis in vivo. Recently, we conjugated Hy to Car and the derivatives (HyCar) showed protective effects in experimental models of osteoarthritis and rheumatoid arthritis in vivo. Here we report the antioxidant activity exerted by HyCar against ROS, RNS and RCS. Moreover, we tested if the covalent conjugation between Hy and Car inhibits the enzymatic hydrolysis of the polymer and the dipeptide backbone. We found that the antioxidant properties and the resistance to the enzymatic hydrolysis of Hy and Car are greatly improved by the conjugation.

Ionophore Ability of Carnosine and Its Trehalose Conjugate Assists Copper Signal in Triggering Brain-Derived Neurotrophic Factor and Vascular Endothelial Growth Factor Activation In Vitro

l-carnosine (β-alanyl-l-histidine) (Car hereafter) is a natural dipeptide widely distributed in mammalian tissues and reaching high concentrations (0.7-2.0 mM) in the brain. The molecular features of the dipeptide underlie the antioxidant, anti-aggregating and metal chelating ability showed in a large number of physiological effects, while the biological mechanisms involved in the protective role found against several diseases cannot be explained on the basis of the above-mentioned properties alone, requiring further research efforts. It has been reported that l-carnosine increases the secretion and expression of various neurotrophic factors and affects copper homeostasis in nervous cells inducing Cu cellular uptake in keeping with the key metal-sensing system. Having in mind this l-carnosine ability, here we report the copper-binding and ionophore ability of l-carnosine to activate tyrosine kinase cascade pathways in PC12 cells and stimulate the expression of BDNF. Furthermore, the study was extended to verify the ability of the dipeptide to favor copper signaling inducing the expression of VEGF. Being aware that the potential protective action of l-carnosine is drastically hampered by its hydrolysis, we also report on the behavior of a conjugate of l-carnosine with trehalose that blocks the carnosinase degradative activity. Overall, our findings describe a copper tuning effect on the ability of l-carnosine and, particularly its conjugate, to activate tyrosine kinase cascade pathways.

Chronic intermittent hypobaric hypoxia attenuates ischemic limb injury by promoting angiogenesis in mice

This study aimed to evaluate the protective effect of chronic intermittent hypobaric hypoxia (CIHH) against limb ischemic injury. C57BL/6 mice were randomly divided into three groups: limb ischemic injury group (Ischemia, induced by ligation and excision of the left femoral artery), limb ischemia following CIHH pretreatment group (CIHH+Ischemia, simulated a 5000 m altitude hypoxia, 6 h per day for 28 days, before induction of hind-limb ischemia), and sham group (Sham). The blood flow in the mouse models of hind-limb ischemia was examined using laser doppler imaging. The functional and morphological performance of ischemic muscle was evaluated using contraction force and hematoxylin-eosin and Masson's trichrome staining. Angiogenesis was determined by immunohistochemistry staining of the endothelial markers CD31 and CD34. The protein expressions of angiogenesis-related genes were detected using Western blot assay. Chronic ischemia resulted in reduced blood perfusion, decreased contraction tension, and morphological destruction in gastrocnemius muscle. CIHH pretreatment increased the contractile force and muscle fiber diameter and decreased necrosis and fibrosis of the ischemic muscle. Also, CIHH significantly increased the density of CD31+ and CD34+ cells and promoted the expression of angiogenesis-related molecules in ischemic muscle. These data demonstrate that CIHH has a protective effect against chronic limb ischemia by promoting angiogenesis.

Dual l-Carnosine/Aloe vera Nanophytosomes with Synergistically Enhanced Protective Effects against Methylglyoxal-Induced Angiogenesis Impairment

Microvascular complications are among the major outcomes of patients with type II diabetes mellitus, which are the consequences of impaired physiological functioning of small blood vessels and angiogenic responses in these patients. Overproduction and accumulation of methylglyoxal (MGO), a highly reactive dicarbonyl byproduct of glycolysis pathway, has been acclaimed as the main inducer of impaired angiogenic responses and microvascular dysfunction in diabetic patients with uncontrolled hyperglycemia. Hence, an effective approach to overcome diabetes-associated microvascular complications is to neutralize the deleterious activity of enhanced the concentration of MGO in the body. Owing to the glycation inhibitory activity of Aloe vera whole extract, and capability of l-carnosine, an endogenous dipeptide, in attenuating MGO's destructive activity, we examined whether application of a combination of l-carnosine and A. vera could be an effective way of synergistically weakening this reactive dicarbonyl's impaired angiogenic effects. Additionally, overcoming the poor cellular uptake and internalization of l-carnosine and A. vera, a nanophytosomal formulation of the physical mixture of two compounds was also established. Although l-carnosine and A. vera at whole studied combination ratios could synergistically enhance viability of human umbilical vein endothelial cells (HUVECs) treated with MGO, the 25:1 w/w ratio was the most effective one among the others (27 ± 0.5% compared to 12 ± 0.3 to 18 ± 0.4%; F (4, 15) = 183.9, P < 0.0001). Developing dual nanophytosomes of l-carnosine/A. vera (25:1) combination ratio, we demonstrated superiority of the nanophytosomal formulation in protecting HUVECs against MGO-induced toxicity following a 24-72 h incubation period (17.3, 15.8, and 12.4% respectively). Moreover, 500 μg/mL concentration of dual l-carnosine/A. vera nanophytosomes exhibited a superior free radical scavenging potency (63 ± 4 RFU vs 83 ± 5 RFU; F (5, 12) = 54.81, P < 0.0001) and nitric oxide synthesizing capacity (26.11 ± 0.19 vs 5.1 ± 0.33; F (5, 12) = 2537, P < 0.0001) compared to their physical combination counterpart. Similarly, 500 μg/mL dual l-carnosine/A. vera nanophytosome-treated HUVECs demonstrated a superior tube formation capacity (15 ± 3 vs 2 ± 0.3; F (5, 12) = 30.87, P < 0.001), wound scratch healing capability (4.92 ± 0.3 vs 3.07 ± 0.3 mm/h; F (5, 12) = 39.21, P < 0.0001), and transwell migration (586 ± 32 vs 394 ± 18; F (5, 12) = 231.8, P < 0.001) and invasion (172 ± 9 vs 115 ± 5; F (5, 12) = 581.1, P < 0.0001) activities compared to the physical combination treated ones. Further confirming the proangiogenic activity of the dual l-carnosine/A. vera nanophytosomes, a significant shift toward expression of proangiogenic genes including HIF-1α, VEGFA, bFGF, KDR, and Ang II was reported in treated HUVECs. Overall, dual l-carnosine/A. vera nanophytosomes could be a potential candidate for attenuating type II DM-associated microvascular complications with an impaired angiogenesis background.

Antiangiogenic Effect of Platelet P2Y12 Inhibitor in Ischemia-Induced Angiogenesis in Mice Hindlimb

PURPOSE

Postischemic inflammation induces angiogenesis, while platelet P2Y12 inhibitors can alleviate this inflammation. Therefore, we studied the potential effects of P2Y12 inhibitor, ticagrelor, on angiogenesis in a mouse model of hindlimb ischemia.

METHODS

Laser Doppler perfusion imaging and capillary density measurement were used for angiogenesis quantified. Immunofluorescence was used to detect the level of CD31. The mice muscle was harvested for enzyme-linked immunosorbent (ELISA) assay of interleukin- (IL) 10 activity and Western blot determination of vascular endothelial growth factor (VEGF) production.

RESULTS

Ischemic hindlimb angiogenesis was sharply decreased in IL-10+/+ mice than IL-10-/- mice. Ticagrelor inhibited angiogenesis and blood reperfusion recovery significantly elevated the levels of IL-10 and decreased the expression of VEGF in the IL-10+/+ mouse ischemic hindlimb, which were abolished in IL-10-deficient (IL-10-/-) C57BL/6J mice.

CONCLUSION

The study underscores that the effect of ticagrelor antiangiogenic function is related with the higher IL-10 expression.

The Role of GSH in Intracellular Iron Trafficking

Evidence is reviewed for the role of glutathione in providing a ligand for the cytosolic iron pool. The possibility of histidine and carnosine forming ternary complexes with iron(II)glutathione is discussed and the physiological significance of these interactions considered. The role of carnosine in muscle, brain, and kidney physiology is far from established and evidence is presented that the iron(II)-binding capability of carnosine relates to this role.

Carnosine research in relation to aging brain and neurodegeneration: A blessing for geriatrics and their neuronal disorders

Carnosine, an endogenous dipeptide (β-Ala-l-His), is enriched in prefrontal cortex and olfactory bulb of the brain, blood and also in muscle. It has mainly antioxidant and antiglycating properties which makes this molecule unique. Its content reduces during aging and aging-induced neurodegenerative diseases. Aging is a progressive biological process that leads to develop the risk factors of diseases and death. During aging the morphological, biochemical, cellular and molecular changes occur in brain and blood including other tissues. The objective of this review is to combine the updated information from the existing literature about the aging-induced neurodegeneration and carnosine research to meet the lacuna of mechanism of carnosine. The grey matter and white matter loses its normal ratio in aging, and hence the brain volume and weight. Different aging related neurodegenerative disorders arise due to loss of neurons, and synapses as a result of proteinopathies in some cases. Carnosine, being an endogenous biomolecule and having antioxidant, antiglycating properties has shown its potency to counteract erroneous protein biosynthesis, stress, activated microglial and astrocyte activity, and different neurodegenerative disorders. It (carnosine) can also inhibit the metal ion-induced degeneration by acting as a metal chelator. In this review the trends in carnosine research in relation to aging brain and neurodegeneration have been discussed with a view to its (carnosine) eligibility (including its mechanism of action) to be used as a promising neurotherapeutic for the betterment of elderly populations of our society at the national and international levels in near future.

Space Flight Diet-Induced Deficiency and Response to Gravity-Free Resistive Exercise

Immune system dysregulation is among the many adverse effects incurred by astronauts during space flights. Omega-3 fatty acids, β-alanine, and carnosine are among the many nutrients that contribute to immune system health. For space flight, crewmembers are prescribed a diet with a macronutrient composition of 55% carbohydrate, 30% fat, and 15% protein. To quantify omega-3 fatty acid, β-alanine and carnosine intakes from such a diet, and to examine each nutrient's impact on exercise performance, 21 participants adhered to the aforementioned macronutrient ratio for 14 days which was immediately followed by a workout performed on gravity-independent resistive exercise hardware. Results included daily omega-3 fatty acid intakes below the suggested dietary intake. Daily omega-3 fatty acid, β-alanine and carnosine intakes each correlated with non-significant amounts of variance from the workout's volume of work. Given the nutritional requirements to maintain immune system function and the demands of in-flight exercise countermeasures for missions of increasingly longer durations current results, in combination with previously published works, imply in-flight supplementation may be a prudent approach to help address the physiological and mental challenges incurred by astronauts on future space flights.