Crocetin restores diabetic endothelial progenitor cell dysfunction by enhancing NO bioavailability via regulation of PI3K/AKT-eNOS and ROS pathways

The Therapeutic Role of Saffron and Its Components Mediated Through Nrf2 in Diabetes and Related Pathologies

Today, diabetes is considered a growing global epidemic. In the diabetic environment, a large amount of reactive oxygen species are produced. This type of active oxygen causes severe damage to cell membranes, proteins, and DNA. Therefore, finding a solution to deal with and reduce this type of reactive oxygen is very important. One of the most effective ways to deal with oxidative damage and inflammation is the modulation of the nuclear factor erythroid 2 (Nrf2) signaling pathway. One of the useful natural substances that can be used for treatment in the signaling system is saffron. In this article, research evaluating the medicinal effects of saffron and its compounds and their mechanisms of action, especially the Nrf2 signaling pathway, have been investigated and studied. The results show that saffron and its components have the potential to treat diabetes due to their unique properties.

Saffron, a Potential Bridge between Nutrition and Disease Therapeutics: Global Health Challenges and Therapeutic Opportunities

Plants are an important source of essential bioactive compounds that not only have a beneficial role in human health and nutrition but also act as drivers for shaping gut microbiome. However, the mechanism of their functional attributes is not fully understood despite their significance. One such important plant is Crocus sativus, also known as saffron, which possesses huge medicinal, nutritional, and industrial applications like food and cosmetics. The importance of this plant is grossly attributed to its incredible bioactive constituents such as crocins, crocetin, safranal, picrocrocin, and glycosides. These bioactive compounds possess a wide range of therapeutic activities against multiple human ailments. Since a huge number of studies have revealed negative unwanted side effects of modern-day drugs, the scientific communities at the global level are investigating a large number of medicinal plants to explore natural products as the best alternatives. Taken into consideration, the available research findings indicate that saffron has a huge scope to be further explored to establish alternative natural-product-based drugs for health benefits. In this review, we are providing an update on the role of bioactive compounds of saffron as therapeutic agents (human disorders and antimicrobial activity) and its nutritional values. We also highlighted the role of omics and metabolic engineering tools for increasing the content of key saffron bioactive molecules for its mass production. Finally, pre-clinical and clinical studies seem to be necessary to establish its therapeutic potential against human diseases.

Association between Relative Thrombocytosis and Microalbuminuria in Adults with Mild Fasting Hyperglycemia

An elevated platelet count may contribute to significant thrombotic events and pose a risk for diabetic microvascular complications. Albuminuria, one of the hallmarks of diabetes, is thought to be a risk factor for endothelial dysfunction. In this study, we investigated the association between relative thrombocytosis and an increased urine albumin-to-creatinine ratio in healthy adult participants. Using multivariate analyses on data from the Korea National Health and Nutrition Examination Survey V-VI, 12,525 eligible native Koreans aged ≥ 20 were categorized into platelet count quintiles by sex. The highest platelet count quintile included younger, more obese participants with elevated white blood cell counts, poor lipid profiles, and a better estimated glomerular filtration rate. Restricted cubic spline regression analysis revealed significant associations between platelet count and fasting blood glucose, glycated hemoglobin, and urine albumin-to-creatinine ratio. Adjusted logistic regression models indicated that heightened fasting blood glucose and platelet count were linked to risk of microalbuminuria (fasting blood glucose, odds ratio = 1.026, 95%CI = 1.011-1.042; platelet count, odds ratio = 1.004, 95%CI = 1.002-1.006). Particularly, an increased platelet count was notably associated with microalbuminuria progression in subjects with impaired fasting glucose. These findings suggest that an elevated platelet count, even below diagnostic thrombocytosis levels, independently correlates with an increased risk of vascular endothelial dysfunction in patients with impaired fasting glucose.

Identification of Crocetin as a Dual Agonist of GPR40 and GPR120 Responsible for the Antidiabetic Effect of Saffron

Crocin, a glycoside of crocetin, has been known as the principal component responsible for saffron's antidiabetic, anticancer, and anti-inflammatory effects. Crocetin, originating from the hydrolytic cleavage of crocin in biological systems, was subjected to ligand-based virtual screening in this investigation. Subsequent biochemical analysis unveiled crocetin, not crocin, as a novel dual GPR40 and GPR120 agonist, demonstrating a marked preference for GPR40 and GPR120 over peroxisome proliferator-activated receptors (PPAR)γ. This compound notably enhanced insulin and GLP-1 secretion from pancreatic β-cells and intestinal neuroendocrine cells, respectively, presenting a dual mechanism of action in glucose-lowering effects. Docking simulations showed that crocetin emulates the binding characteristics of natural ligands through hydrogen bonds and hydrophobic interactions, whereas crocin's hindered fit within the binding pocket is attributed to steric constraints. Collectively, for the first time, this study unveils crocetin as the true active component of saffron, functioning as a GPR40/120 agonist with potential implications in antidiabetic interventions.

Carvacrol Improves Vascular Function in Hypertensive Animals by Modulating Endothelial Progenitor Cells

Carvacrol, a phenolic monoterpene, has diverse biological activities, highlighting its antioxidant and antihypertensive capacity. However, there is little evidence demonstrating its influence on vascular regeneration. Therefore, we evaluated the modulation of carvacrol on endothelial repair induced by endothelial progenitor cells (EPC) in hypertension. Twelve-week-old spontaneously hypertensive rats (SHR) were treated with a vehicle, carvacrol (50 or 100 mg/kg/day), or resveratrol (10 mg/kg/day) orally for four weeks. Wistar Kyoto (WKY) rats were used as the normotensive controls. Their systolic blood pressure (SBP) was measured weekly through the tail cuff. The EPCs were isolated from the bone marrow and peripherical circulation and were quantified by flow cytometry. The functionality of the EPC was evaluated after cultivation through the quantification of colony-forming units (CFU), evaluation of eNOS, intracellular detection of reactive oxygen species (ROS), and evaluation of senescence. The superior mesenteric artery was isolated to evaluate the quantification of ROS, CD34, and CD31. Treatment with carvacrol induced EPC migration, increased CFU formation and eNOS expression and activity, and reduced ROS and senescence. In addition, carvacrol reduced vascular ROS and increased CD31 and CD34 expression. This study showed that treatment with carvacrol improved the functionality of EPC, contributing to the reduction of endothelial dysfunction.

Emodin protects against homocysteine-induced cardiac dysfunction by inhibiting oxidative stress via MAPK and Akt/eNOS/NO signaling pathways

Elevated levels of plasma homocysteine (Hcy) causes severe cardiac dysfunction, which is closely associated with oxidative stress. Emodin, a naturally occurring anthraquinone derivative, has been shown to exert antioxidant and anti-apoptosis activities. However, whether emodin could protect against Hcy-induced cardiac dysfunction remains unknown. The current study aimed to investigate the effects of emodin on the Hcy-induced cardiac dysfunction and its molecular mechanisms. Rats were fed a methionine diet to establish the animal model of hyperhomocysteinemia (HHcy). H9C2 cells were incubated with Hcy to induce a cell model of Hcy-injured cardiomyocytes. ELISA, HE staining, carotid artery and left ventricular cannulation, MTT, fluorescence staining, flow cytometry and western blotting were used in this study. Emodin significantly alleviated the structural damage of the myocardium and cardiac dysfunction from HHcy rats. Emodin prevented apoptosis and the collapse of MMP in the Hcy-treated H9C2 cells in vitro. Further, emodin reversed the Hcy-induced apoptosis-related biochemical changes including decreased Bcl-2/Bax protein ratio, and increased protein expression of Caspase-9/3. Moreover, emodin suppressed oxidative stress in Hcy-treated H9C2 cells. Mechanistically, emodin significantly inhibited the Hcy-activated MAPK by reducing ROS generation in H9C2 cells. Furthermore, emodin upregulated NO production by promoting the protein phosphorylation of Akt and eNOS in injured cells. The present study shows that emodin protects against Hcy-induced cardiac dysfunction by inhibiting oxidative stress via MAPK and Akt/eNOS/NO signaling pathways.

Zhijing powder manages blood pressure by regulating PI3K/AKT signal pathway in hypertensive rats

Background

Zhijing Powder (ZJP) is a traditional Chinese medicine containing two kinds of Chinese medicine. Those studies analyze the molecular mechanism of ZJP in treating hypertension through network pharmacology, combined with animal experiments.

Methods

First, the effective ingredients and potential targets of the drug were obtained through drug databases, while the targets of disease obtained through disease target databases. The potential targets, cellular bioanalysis and signaling pathways were found in some platforms by analyzing collected targets. Further experiments were conducted to verify the effect and mechanism of drugs on cold and high salt in an induced-hypertension rat model.

Results

There are 17 effective components of centipedes and 10 of scorpions, with 464 drug targets obtained after screening. A total of 1263 hypertension targets were obtained after screening and integration, resulting in a protein-protein interaction network (PPI) with 145 points and 1310 edges. Gene ontology (GO) analysis shows that blood circulation regulation and activation of G protein-coupled receptors are mainly biological processes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis shows that neuroactive ligand-receptor interaction, calcium signaling pathways, PI3K-AKT signaling pathways are the most abundant gene-enriched pathway. Animal experiments indicated that ZJP can reduce blood pressure (BP), affect expression of the PI3K-AKT signaling pathway, and improve oxidative stress in the body.

Conclusion

ZJP ameliorates oxidative stress and reduces BP in hypertensive rats caused by cold stimuli and high salt, revealing its effect on the expression of the PI3K/AKT signaling pathway in the rat aorta.

Saffron as a promising therapy for diabetes and Alzheimer's disease: mechanistic insights

The prevalence of both Alzheimer's disease (AD) and diabetes mellitus is increasing with the societies' aging and has become an essential social concern worldwide. Accumulation of amyloid plaques and neurofibrillary tangles (NFTs) of tau proteins in the brain are hallmarks of AD. Diabetes is an underlying risk factor for AD. Insulin resistance has been proposed to be involved in amyloid-beta (Aβ) aggregation in the brain. It seems that diabetic conditions can result in AD pathology by setting off a cascade of processes, including inflammation, mitochondrial dysfunction, and ROS and advanced glycation end products (AGEs) synthesis. Due to the several side effects of chemical drugs and their high cost, using herbal medicine has recently attracted attention for the treatment of diabetes and AD. Saffron and its active ingredients have been used for its anti-inflammatory, anti-oxidant, anti-diabetic, and anti-AD properties. Therefore, in the present review paper, we take account of the clinical, in vivo and in vitro evidence regarding the anti-diabetic and anti-AD effects of saffron and discuss the preventive or postponing properties of saffron or its components on AD development via its anti-diabetic effects.

Hydrogen Repairs LPS-Induced Endothelial Progenitor Cells Injury via PI3K/AKT/eNOS Pathway

Endotoxins and other harmful substances may cause an increase in permeability in endothelial cells (ECs) monolayers, as well as ECs shrinkage and death to induce lung damage. Lipopolysaccharide (LPS) can impair endothelial progenitor cells (EPCs) functions, including proliferation, migration, and tube formation. EPCs can migrate to the damaged area, differentiate into ECs, and participate in vascular repair, which improves pulmonary capillary endothelial dysfunction and maintains the integrity of the endothelial barrier. Hydrogen (H2) contributes to the repairment of lung injury and the damage of ECs. We therefore speculate that H2 protects the EPCs against LPS-induced damage, and it's mechanism will be explored. The bone marrow-derived EPCs from ICR Mice were treated with LPS to establish a damaged model. Then EPCs were incubated with H2, and treated with PI3K inhibitor LY294002 and endothelial nitric oxide synthase (eNOS) inhibitor L-NAME. MTT assay, transwell assay and tube formation assay were used to detect the proliferation, migration and angiogenesis of EPCs. The expression levels of target proteins were detected by Western blot. Results found that H2 repaired EPCs proliferation, migration and tube formation functions damaged by LPS. LY294002 and L-NAME significantly inhibited the repaired effect of H2 on LPS-induced dysfunctions of EPCs. H2 also restored levels of phosphor-AKT (p-AKT), eNOS and phosphor-eNOS (p-eNOS) suppressed by LPS. LY294002 significantly inhibited the increase of p-AKT and eNOS and p-eNOS expression exposed by H2. L-NAME significantly inhibited the increase of eNOS and p-eNOS expression induced by H2. H2 repairs the dysfunctions of EPCs induced by LPS, which is mediated by PI3K/AKT/eNOS signaling pathway.

Crocetin: A Systematic Review

Crocetin is an aglycone of crocin naturally occurring in saffron and produced in biological systems by hydrolysis of crocin as a bioactive metabolite. It is known to exist in several medicinal plants, the desiccative ripe fruit of the cape jasmine belonging to the Rubiaceae family, and stigmas of the saffron plant of the Iridaceae family. According to modern pharmacological investigations, crocetin possesses cardioprotective, hepatoprotective, neuroprotective, antidepressant, antiviral, anticancer, atherosclerotic, antidiabetic, and memory-enhancing properties. Although poor bioavailability hinders therapeutic applications, derivatization and formulation preparation technologies have broadened the application prospects for crocetin. To promote the research and development of crocetin, we summarized the distribution, preparation and production, total synthesis and derivatization technology, pharmacological activity, pharmacokinetics, drug safety, drug formulations, and preparation of crocetin.

Regulation of endothelial progenitor cell functions during hyperglycemia: new therapeutic targets in diabetic wound healing

Diabetes is primarily characterized by hyperglycemia, and its high incidence is often very costly to patients, their families, and national economies. Unsurprisingly, the number and function of endothelial progenitor cells (EPCs) decrease in patients resulting in diabetic wound non-healing. As precursors of endothelial cells (ECs), these cells were discovered in 1997 and found to play an essential role in wound healing. Their function, number, and role in wound healing has been widely investigated. Hitherto, a lot of complex molecular mechanisms have been discovered. In this review, we summarize the mechanisms of how hyperglycemia affects the function and number of EPCs and how the affected cells impact wound healing. We aim to provide a complete summary of the relationship between diabetic hyperglycosemia, EPCs, and wound healing, as well as a better comprehensive platform for subsequent related research.

Astragaloside IV prevents endothelial dysfunction by improving oxidative stress in streptozotocin-induced diabetic mouse aortas

Oxidative stress serves a role in endothelial dysfunction exhibited by patients with diabetes mellitus. Astragaloside IV (AS-IV) is a major active ingredient of Radix Astragali, which is considered to exhibit vasoprotective effects through unknown mechanisms. Thus, the current study was performed to investigate the protective effects of AS-IV in streptozotocin (STZ)-induced endothelial dysfunction and to explore whether antioxidant mechanisms were involved. The protective effects of AS-IV on the endothelium-dependent relaxation and contraction of aortic rings were determined by isometric tension recordings. NADPH subunits and endothelial nitric oxide synthase (eNOS) expression was identified via western blotting. Superoxide dismutase and malondialdehyde levels were assayed using ELISA. Furthermore, the generation of reactive oxygen species (ROS) and nitric oxide (NO) was detected via dihydroethidium and 4,5-diaminofluorescein diacetate staining, respectively. The results revealed that STZ-injected mice exhibited increased aortic endothelium-dependent vasoconstriction and decreased vasorelaxation to acetylcholine. However, AS-IV treatment reversed these effects. N^G-nitro-L-arginine was subsequently used to completely inhibit impaired relaxation. Accordingly, impaired NO generation was restored following AS-IV treatment by increasing eNOS phosphorylation levels. Furthermore, ROS formation was also depressed following AS-IV treatment compared with that in STZ-injected mice. AS-IV also decreased the expression of various NADPH subunits, including human neutrophil cytochrome b light chain, neutrophil cytosolic factor 1, NADPH oxidase (NOX)2, NOX4 and Rac-1. The results of the current study may provide novel evidence that diabetes-induced vascular injury arises from either the inhibition of eNOS or the activation of NOX-derived ROS generation. In addition, the results warrant further investigation into the application of AS-IV treatment, leading to the improvement of oxidative stress, in patients with diabetes exhibiting endothelial dysfunction.

Salvianic Acid A Regulates High-Glucose-Treated Endothelial Progenitor Cell Dysfunction via the AKT/Endothelial Nitric Oxide Synthase (eNOS) Pathway

BACKGROUND The primary cause of death in patients with diabetes mellitus (DM) is diabetic macroangiopathy, a complication that related to the function and number of endothelial progenitor cells (EPCs). Salvianic acid A (SAA) is a water-soluble active ingredient of Salvia miltiorrhiza, a traditional Chinese medicine used to treat cardiovascular diseases. The purpose of this study was to explore the effects of SAA on the function of rat EPCs cultured in vitro in a high-glucose environment. MATERIAL AND METHODS Bone marrow-derived EPCs from 40 Sprague-Dawley rats were identified by fluorescence staining. Cell viability, apoptosis, tube formation, lactated dehydrogenase (LDH) release, and nitric oxide (NO) production were detected by 3-[4,5-dimethylthylthiazol-2-yl]-2,5 diphenyltetrazolium bromide assay, flow cytometry, tube formation, LDH, and 3-amino,4-aminomethyl-2',7'-difluorescein, and diacetate assays, respectively. The expression levels of proteins were examined by western blotting. RESULTS Cultured EPCs showed a cobblestone morphology and positive expression of Dil-ac-LDL and FITC-UEA-1. High glucose impaired cell viability. Different concentrations of SAA had no significant effect on EPC viability. SAA reduced the apoptosis rate and LDH release, but promoted tube formation, viability, and NO production in high-glucose-treated EPCs. The ratios of p-AKT/AKT and p-eNOS/eNOS in high-glucose-treated EPCs were elevated by SAA. Phosphoinositide 3-kinase inhibitor LY294002 blocked the rescue effects of SAA on high-glucose-treated EPCs. CONCLUSIONS SAA protected EPCs against high-glucose-induced dysfunction via the AKT/eNOS pathway.

MiR-34a inhibitor protects mesenchymal stem cells from hyperglycaemic injury through the activation of the SIRT1/FoxO3a autophagy pathway

BACKGROUND

Mesenchymal stem cells (MSCs) are favourable treatments for ischaemic diseases; however, MSCs from diabetic patients are not useful for this purpose. Recent studies have shown that the expression of miR-34a is significantly increased in patients with hyperglycaemia; the precise role of miR-34a in MSCs in diabetes needs to be clarified.

OBJECTIVE

The aim of this study is to determine the precise role of miR-34a in MSCs exposed to hyperglycaemia and in recovery heart function after myocardial infarction (MI) in diabetes mellitus (DM) rats.

METHODS

DM rat models were established by high-fat diet combined with streptozotocin (STZ) injection. MSCs were isolated from the bone marrow of donor rats. Chronic culture of MSCs under high glucose was used to mimic the DM micro-environment. The role of miR-34a in regulating cell viability, senescence and paracrine effects were investigated using a cell counting kit-8 (CCK-8) assay, senescence-associated β-galactosidase (SA-β-gal) staining and vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) ELISA, respectively. The expression of autophagy- and senescence-associated proteins in MSCs and silent information regulator 1 (SIRT1) and forkhead box class O 3a (FoxO3a) were analysed by western blotting. Autophagic bodies were analysed by transmission electron microscopy (TEM). The MI model was established by left anterior descending coronary artery (LAD) ligation, and then, the rats were transplanted with differentially treated MSCs intramuscularly at sites around the border zone of the infarcted heart. Thereafter, cardiac function in rats in each group was detected via cardiac ultrasonography at 1 week and 3 weeks after surgery. The infarct size was determined through a 2,3,5-triphenyltetrazolium chloride (TTC) staining assay, while myocardial fibrosis was assessed by Masson staining.

RESULTS

The results of the current study showed that miR-34a was significantly increased under chronic hyperglycaemia exposure. Overexpression of miR-34a was significantly associated with impaired cell viability, exacerbated senescence and disrupted cell paracrine capacity. Moreover, we found that the mechanism underlying miR-34a-mediated deterioration of MSCs exposed to high glucose involved the activation of the SIRT1/FoxO3a autophagy pathway. Further analysis showed that miR-34a inhibitor-treated MSC transplantation could improve cardiac function and decrease the scar area in DM rats.

CONCLUSIONS

Our study demonstrates for the first time that miR-34a mediates the deterioration of MSCs' functions under hyperglycaemia. The underlying mechanism may involve the SIRT1/FoxO3a autophagy signalling pathway. Thus, inhibition of miR-34a might have important therapeutic implications in MSC-based therapies for myocardial infarction in DM patients.

Crocetin protects against fulminant hepatic failure induced by lipopolysaccharide/D-galactosamine by decreasing apoptosis, inflammation and oxidative stress in a rat model

Fulminant hepatic failure (FHF) is a clinical syndrome characterized by sudden and severe liver dysfunction. Apoptosis and inflammation are essential for the pathogenesis of FHF. Crocetin, the major component present in saffron, has been reported to possess anti-inflammatory and antioxidant functions; however, its role in FHF is poorly understood. The aim of this study was to explore the protective effects of crocetin against lipopolysac§§charide (LPS)/D-galactosamine (D-GalN)-induced FHF and the underlying mechanisms in a rat model. For the in vivo study, rats were assigned to the LPS/D-GalN group or to the crocetin pre-treatment+LPS/D- GalN group. Each group was then further divided according to the different LPS/D-GalN treatment times of 0, 6, 12 or 48 h. The results demonstrated that crocetin pre-treatment efficiently protected against LPS/D-GalN-induced FHF by improving liver tissue morphology, reducing total bilirubin generation and decreasing the activities of alanine transaminase and aspartate aminotransferase. Moreover, crocetin pre-treatment significantly decreased hepatocyte apoptosis, p53 mRNA expression and the expression of proteins in the caspase family and the Bcl-2 pro-apoptotic family following LPS/D-GalN treatment. Furthermore, crocetin also decreased the secretion of pro-inflammatory cytokines in the serum and in the liver via suppression of NF-κB activation, and also suppressed hepatic oxidative stress. In conclusion, crocetin protected against LPS/D-GalN-induced FHF and inhibited apoptosis, inflammation and oxidative stress. The underlying mechanisms may be related to the regulation of apoptotic proteins in the caspase family and the Bcl-2 family, as well as the modulation of NF-κB expression. Therefore, crocetin may be used as a novel therapy for preventing FHF.

The Effect of Dietary Supplementation of Crocetin for Myopia Control in Children: A Randomized Clinical Trial

The prevalence of myopia has been increasing in recent years. The natural carotenoid crocetin has been reported to suppress experimental myopia in mice. We evaluated the effects of crocetin on myopia suppression in children. A multicenter randomized double-blind placebo-controlled clinical trial was performed with 69 participants aged 6 to 12 years, whose cycloplegic spherical equivalent refractions (SER) were between -1.5 and -4.5 diopter (D). The participants were randomized to receive either a placebo or crocetin and followed up for 24 weeks. Axial length (AL) elongation and changes in SER were evaluated for 24 weeks. Both written informed assent from the participants and written informed consent from legal guardians were obtained in this study because the selection criteria of this trial included children aged between 6 and 12 years old. This trial was approved by the institutional review boards. A mixed-effects model was used for analysis, using both eyes. Two participants dropped out and 67 children completed this trial. The change in SER in the placebo group, -0.41 ± 0.05 D (mean ± standard deviation), was significantly more myopic compared to that in the crocetin group, -0.33 ± 0.05 D (p = 0.049). The AL elongation in the placebo group, 0.21 ± 0.02 mm, was significantly bigger than that in the crocetin group, 0.18 ± 0.02 mm (p = 0.046). In conclusion, dietary crocetin may have a suppressive effect on myopia progression in children, but large-scale studies are required in order to confirm this effect.

Angiogenic Factor AGGF1-Primed Endothelial Progenitor Cells Repair Vascular Defect in Diabetic Mice

Hyperglycemia-triggered vascular abnormalities are the most serious complications of diabetes mellitus (DM). The major cause of vascular dysfunction in DM is endothelial injury and dysfunction associated with the reduced number and dysfunction of endothelial progenitor cells (EPCs). A major challenge is to identify key regulators of EPCs to restore DM-associated vascular dysfunction. We show that EPCs from heterozygous knockout Aggf1^+/- mice presented with impairment of proliferation, migration, angiogenesis, and transendothelial migration as in hyperglycemic mice fed a high-fat diet (HFD) or db/db mice. The number of EPCs from Aggf1^+/- mice was significantly reduced. Ex vivo, AGGF1 protein can fully reverse all damaging effects of hyperglycemia on EPCs. In vivo, transplantation of AGGF1-primed EPCs successfully restores blood flow and blocks tissue necrosis and ambulatory impairment in HFD-induced hyperglycemic mice or db/db mice with diabetic hindlimb ischemia. Mechanistically, AGGF1 activates AKT, reduces nuclear localization of Fyn, which increases the nuclear level of Nrf2 and expression of antioxidative genes, and inhibits reactive oxygen species generation. These results suggest that Aggf1 is required for essential function of EPCs, AGGF1 fully reverses the damaging effects of hyperglycemia on EPCs, and AGGF1 priming of EPCs is a novel treatment modality for vascular complications in DM.

A comprehensive review on biological activities and toxicology of crocetin

Natural products with high pharmacological potential and low toxicity have been considered as the novel therapeutic agents. Crocetin is an active constituent of saffron (Crocus sativus L.) stigma, which in its free-acid form is insoluble in water and most organic solvents. Crocetin exhibits various health-promoting properties including anti-tumor, neuroprotective effects, anti-diabetics, anti-inflammatory, anti-hyperlipidemia, etc. These therapeutic effects can be achieved with different mechanisms such as improvement of oxygenation in hypoxic tissues, antioxidant effects, inhibition of pro-inflammatory mediators, anti-proliferative activity and stimulation of apoptosis in cancer cells. It is also worth considering that crocetin could be tolerated without major toxicity at therapeutic dosage in experimental models. In the present review, we discuss the biosynthesis, pharmacokinetic properties of crocetin and provide a comprehensive study on the biological activities and toxicity along with the mechanism of actions and clinical trials data of crocetin.

Insulin promotes macrophage phenotype transition through PI3K/Akt and PPAR-γ signaling during diabetic wound healing

Overactivation and persistent chronic inflammation are the major pathogenic characteristics of diabetic-impaired healing, and diabetic wound healing can be promoted by stimulating the transition of macrophage phenotype from pro-inflammatory (M1) to anti-inflammatory (M2). Our previous studies found that the application of insulin induced an advanced initiation and resolution of inflammatory response. To further explore the mechanism, we have investigated the effect of insulin on macrophage phenotype switch utilizing a diabetic rat model and a human monocytic THP-1 cell. We have utilized the high glucose (HG) and HG plus insulin to stimulate the M1 macrophages derived from lipopolysaccharide-treated THP-1 cells. We studied the secretion of inflammatory mediator and related signaling pathways by using western blot test, immunofluorescence, and Rac1 pull-down assay. We have found that the production of pro-inflammatory mediators, which thereafter induced macrophage polarization toward M1 phenotype, has been elevated due to consistent HG exposure. HG plus insulin stimulation, on the other hand, promoted anti-inflammatory effects. Experiments performed on diabetic burn wounds indicated that the insulin modulated macrophages transition from M1 to M2 phenotype. We found that PI3K/Akt/Rac-1 and PPAR-γ signaling pathways are involved in the anti-inflammatory effect of insulin. Insulin inhibited HG-induced activation of p38, NF-κB, and STAT1 transcriptional activity by activating Akt-Rac-1 signaling. Moreover, insulin performs anti-inflammatory effects through upregulation of PPAR-γ expression and induced P38-mediated dephosphorylation of PPAR-γ (Ser112). In conclusion, insulin downregulates inflammatory response, regulates M1 macrophage transition in response to HG, and thus improves chronic wound healing.

Downregulated GTCPH I/BH4 Pathway and Decreased Function of Circulating Endothelial Progenitor Cells and Their Relationship with Endothelial Dysfunction in Overweight Postmenopausal Women

Endothelial progenitor cells (EPCs) have endogenous endothelium-reparative potential, but obesity impairs EPCs. Overweight premenopausal women have a normal number of circulating EPCs with functional activity, but whether EPCs in overweight postmenopausal women can repair obesity-related endothelial damage requires further investigation. For this purpose, we examined the function and number of circulating EPCs, evaluated vascular endothelial function, and explored the underlying mechanism. Compared with normal weight or overweight age-matched men, postmenopausal women (overweight or normal weight) had a diminished number of circulating EPCs and impaired vascular endothelial function, as detected by flow-mediated dilatation. Moreover, GTCPH I expression and the nitric oxide level in overweight postmenopausal women and men were significantly decreased. Together, our findings demonstrate that the number or function of circulating EPCs and endothelial function, which is partially regulated by the GTCPH I/BH4 signaling pathway, is not preserved in overweight postmenopausal women. The GTCPH I/BH4 pathway in circulating EPCs may be a potential therapeutic target for endothelial injury in overweight postmenopausal women.

Multiple therapeutic effect of endothelial progenitor cell regulated by drugs in diabetes and diabetes related disorder

BACKGROUND

Reduced levels of endothelial progenitor cells (EPCs) counts have been reported in diabetic mellitus (DM) patients and other diabetes-related disorder. EPCs are a circulating, bone marrow-derived cell population that appears to participate in vasculogenesis, angiogenesis and damage repair. These EPC may revert the damage caused in diabetic condition. We aim to identify several existing drugs and signaling molecule, which could alleviate or improve the diabetes condition via mobilizing and increasing EPC number as well as function.

MAIN BODY

Accumulated evidence suggests that dysregulation of EPC phenotype and function may be attributed to several signaling molecules and cytokines in DM patients. Hyperglycemia alone, through the overproduction of reactive oxygen species (ROS) via eNOS and NOX, can induce changes in gene expression and cellular behavior in diabetes. Furthermore, reports suggest that EPC telomere shortening via increased oxidative DNA damage may play an important role in the pathogenesis of coronary artery disease in diabetic patients. In this review, different type of EPC derived from different sources has been discussed along with cell-surface marker. The reduced number and immobilized EPC in diabetic condition have been mobilized for the therapeutic purpose via use of existing, and novel drugs have been discussed. Hence, evidence list of all types of drugs that have been reported to target the same pathway which affect EPC number and function in diabetes has been reviewed. Additionally, we highlight that proteins are critical in diabetes via polymorphism and inhibitor studies. Ultimately, a lucid pictorial explanation of diabetic and normal patient signaling pathways of the collected data have been presented in order to understand the complex signaling mystery underlying in the diseased and normal condition.

CONCLUSION

Finally, we conclude on eNOS-metformin-HSp90 signaling and its remedial effect for controlling the EPC to improve the diabetic condition for delaying diabetes-related complication. Altogether, the review gives a holistic overview about the elaborate therapeutic effect of EPC regulated by novel and existing drugs in diabetes and diabetes-related disorder.