Oral chromium picolinate impedes hyperglycemia-induced atherosclerosis and inhibits proatherogenic protein TSP-1 expression in STZ-induced type 1 diabetic ApoE-/- mice

Is chromium(III) pharmacologically relevant? An update focused on studies with diabetic rodent models

A decade ago, the author assessed the status of chromium as the trivalent ion as an essential element and as a therapeutic agent based on rodent studies for this journal. The current review was undertaken to update considerations regarding the status of chromium, focusing on studies of Cr supplementation of diabetic rodent models over the last decade. Cr can no longer be considered an essential trace element for humans. Observed effects of Cr on rodent models of insulin resistance and diabetes are best interpreted in terms of a pharmacological role for Cr. The review of studies on the effects of Cr on rat models of diabetes is updated, and the results continue to suggest Cr increases insulin sensitivity in peripheral tissues of the rodent models. The lack of effects in human studies may stem from humans receiving a comparably smaller dose than the rodent models. However, given the different responses to Cr in the rodent models, humans could potentially have different responses to Cr. Recent studies primary utilizing rodents suggest two potential complementary but also contradictory modes of action for Cr(III) at a molecular level.

Chromium Picolinate Regulates Bone Metabolism and Prevents Bone Loss in Diabetic Rats

Diabetic osteoporosis (DOP) is an abnormal metabolic disease caused by long-term hyperglycemia. In this study, a model rat of streptozotocin (STZ)-induced diabetes was established, and chromium picolinate (5 mg·kg-1) was given; the changes in blood glucose and body weight were detected before and after administration; and bone mineral density (BMD), bone morphology, bone turnover markers, inflammatory cytokines, and oxidative stress indicators were observed in each group. We found that after chromium picolinate (CP) intervention for 8 weeks, the blood glucose level was decreased; the BMD, the bone histomorphology parameters, and the pathological structure were improved; the expression of bone resorption-related proteins was downregulated; and the expression of bone formation-related proteins was upregulated. Meanwhile, serum antioxidant activity was increased, and inflammatory cytokine levels were decreased. In conclusion, CP could alleviate DOP by anti-oxidation, inhibition of bone turnover, anti-inflammation, and regulation of the OPG/RANKL/RANK signaling pathway. Therefore, CP has important application values for further development as a functional food or active medicine in DOP treatment.

Relationship between elevated circulating thrombospondin-1 levels and vascular complications in diabetes mellitus

AIMS/INTRODUCTION

Thrombospondin-1 (TSP-1) participates in a series of physiological and pathological processes by binding to various receptors regulating cell proliferation, adhesion and apoptosis. Elevated circulating TSP-1 is linked with diabetic vascular complications (DVC). This study aimed to determine the relationship between circulating TSP-1 levels and DVC.

MATERIALS AND METHODS

A comprehensive search of PubMed, Embase, Web of Science and CNKI databases was carried out. A meta-analysis was carried out to compare circulating TSP-1 levels between diabetes patients without vascular complications (DNVC), diabetes patients with DVC and non-diabetes patients. The correlation between TSP-1 and metabolic parameters was also analyzed. Subgroup analysis was carried out according to complication type, defined as diabetic retinopathy, diabetic nephropathy and diabetic cardiovascular disease (DCVD).

RESULTS

A total of eight studies were included. Compared with non-diabetes patients, diabetic patients, including DNVC and DVC, had significantly higher circulating TSP-1 levels (standardized mean difference [SMD] 2.660, 95% CI 1.17-4.145, P = 0.000). DNVC had significantly higher circulating TSP-1 levels than non-diabetes patients (SMD 3.613, 95% CI 1.607-5.619, P = 0.000). DVC had significantly higher TSP-1 levels than DNVC (SMD 0.568, 95% CI 0.100-1.036, P = 0.017). TSP-1 was significantly positively correlated with fasting plasma glucose (overall Fisher's z = 0.696, 95% CI 0.559-0.833) and HbA1c (overall Fisher's z = 0.849, 95% CI 0.776-0.923).

CONCLUSIONS

Elevated circulating TSP-1 levels are closely related to DVC, especially in diabetic nephropathy and diabetic cardiovascular disease. Circulating TSP-1 detection might be helpful in the timely diagnosis and treatment of DVC.

PIAS1 impedes vascular endothelial injury and atherosclerotic plaque formation in diabetes by blocking the RUNX3/TSP-1 axis

The protein PIAS1 functions as a type of ubiquitin-protease, which is known to play an important regulatory role in various diseases, including cardiovascular diseases and cancers. Its mechanism of action primarily revolves around regulating the transcription, translation, and modification of target proteins. This study investigates role and mechanism of PIAS1 in the RUNX3/TSP-1 axis and confirms its therapeutic effects on diabetes-related complications in animal models. A diabetic vascular injury was induced in human umbilical vein endothelial cells (HUVECs) by stimulation with H2O2 and advanced glycation end product (AGE), and a streptozotocin (STZ)-induced mouse model of diabetes was constructed, followed by detection of endogenous PIAS1 expression and SUMOylation level of RUNX3. Effects of PIAS1 concerning RUNX3 and TSP-1 on the HUVEC apoptosis and inflammation were evaluated using the ectopic expression experiments. Down-regulated PIAS1 expression and SUMOylation level of RUNX3 were identified in the H2O2- and AGE-induced HUVEC model of diabetic vascular injury and STZ-induced mouse models of diabetes. PIAS1 promoted the SUMOylation of RUNX3 at the K148 site of RUNX3. PIAS1-mediated SUMOylation of RUNX3 reduced RUNX3 transactivation activity, weakened the binding of RUNX3 to the promoter region of TSP-1, and caused downregulation of TSP-1 expression. PIASI decreased the expression of TSP-1 by inhibiting H2O2- and AGE-induced RUNX3 de-SUMOylation, thereby arresting the inflammatory response and apoptosis of HUVECs. Besides, PIAS1 reduced vascular endothelial injury and atherosclerotic plaque formation in mouse models of diabetes by inhibiting the RUNX3/TSP-1 axis. Our study proved that PIAS1 suppressed vascular endothelial injury and atherosclerotic plaque formation in mouse models of diabetes via the RUNX3/TSP-1 axis.

Deletion of Smooth Muscle O-GlcNAc Transferase Prevents Development of Atherosclerosis in Western Diet-Fed Hyperglycemic ApoE-/- Mice In Vivo

Accumulating evidence highlights protein O-GlcNAcylation as a putative pathogenic contributor of diabetic vascular complications. We previously reported that elevated protein O-GlcNAcylation correlates with increased atherosclerotic lesion formation and VSMC proliferation in response to hyperglycemia. However, the role of O-GlcNAc transferase (OGT), regulator of O-GlcNAc signaling, in the evolution of diabetic atherosclerosis remains elusive. The goal of this study was to determine whether smooth muscle OGT (smOGT) plays a direct role in hyperglycemia-induced atherosclerotic lesion formation and SMC de-differentiation. Using tamoxifen-inducible Myh11-CreERT2 and Ogtfl/fl mice, we generated smOGTWT and smOGTKO mice, with and without ApoE-null backgrounds. Following STZ-induced hyperglycemia, smOGTWT and smOGTKO mice were kept on a standard laboratory diet for the study duration. In a parallel study, smOGTWTApoE-/- and smOGTKOApoE-/- were initiated on Western diet at 8-wks-age. Animals harvested at 14-16-wks-age were used for plasma and tissue collection. Loss of smOGT augmented SM contractile marker expression in aortic vessels of STZ-induced hyperglycemic smOGTKO mice. Consistently, smOGT deletion attenuated atherosclerotic lesion lipid burden (Oil red O), plaque area (H&E), leukocyte (CD45) and smooth muscle cell (ACTA2) abundance in Western diet-fed hyperglycemic smOGTKOApoE-/- mice. This was accompanied by increased SM contractile markers and reduced inflammatory and proliferative marker expression. Further, smOGT deletion attenuated YY1 and SRF expression (transcriptional regulators of SM contractile genes) in hyperglycemic smOGTKOApoE-/- and smOGTKO mice. These data uncover an athero-protective outcome of smOGT loss-of-function and suggest a direct regulatory role of OGT-mediated O-GlcNAcylation in VSMC de-differentiation in hyperglycemia.

Sex-specific differences in atherosclerosis, thrombospondin-1, and smooth muscle cell differentiation in metabolic syndrome versus non-metabolic syndrome mice

Introduction

Metabolic syndrome (MetS) amplifies the risks of atherosclerosis. Despite well-known sexual dimorphism in atherosclerosis, underlying mechanisms are poorly understood. Our previous findings highlight a proatherogenic protein, thrombospondin-1 (TSP-1), in hyperglycemia- or hyperleptinemia (mimicking obesity)-induced atherosclerosis. However, the role of TSP-1 in the development of atherosclerosis prompted by co-existing hyperglycemia and obesity, characteristic of MetS, is unknown. The goal of this study was to examine sex-specific differences in lesion progression in a model of combined MetS and atherosclerosis (KKAyApoE) and interrogate how these differences relate to TSP-1 expression.

Methods

Male and female KKAy^+/-ApoE^-/- (with ectopic agouti gene expression) and age-matched non-agouti KKAy^-/-ApoE^-/- littermates were placed on a standard laboratory diet from 4 to 24 weeks age followed by blood and tissue harvests for biochemical, molecular, and aortic root morphometric studies.

Results

Metabolic profiling confirmed MetS phenotype of KKAy^+/-ApoE^-/-; however, only male genotypes were glucose intolerant with elevated VLDL-cholesterol and VLDL-triglyceride levels. Aortic root morphometry demonstrated profound lipid-filled lesions, increased plaque area, and augmented inflammatory and SMC abundance in MetS vs non-MetS males. This increase in lesion burden was accompanied with elevated TSP-1 and attenuated LMOD-1 (SM contractile marker) and SRF (transcriptional activator of SM differentiation) expression in male MetS aortic vessels. In contrast, while lipid burden, plaque area, and TSP-1 expression increased in MetS and non-MetS female mice, there was no significant difference between these genotypes. Increased collagen content was noted in MetS and non-MetS genotypes, specific to female mice. Measurement of plasma testosterone revealed a link between the atherogenic phenotype and abnormally high or low testosterone levels. To interrogate whether TSP-1 plays a direct role in SMC de-differentiation in MetS, we generated KKAy^+/- mice with and without global TSP-1 deletion. Immunoblotting showed increased SM contractile markers in male KKAy^+/-TSP-1^-/- aortic vessels vs male KKAy^+/-TSP-1^{+/ +}. In contrast, TSP-1 deletion had no effect on SM contractile marker expression in female genotypes.

Conclusion

Together, the current study implicates a role of plasma testosterone in sex-specific differences in atherosclerosis and TSP-1 expression in MetS vs non-MetS mice. Our data suggest a sex-dependent differential role of TSP-1 on SMC de-differentiation in MetS. Collectively, these findings underscore a fundamental link between TSP-1 and VSMC phenotypic transformation in MetS.

Multi-biomarker approach to assess chromium, pH and temperature toxicity in fish

Chromium (Cr) is considered as the most common ubiquitous pollutant for aquatic animals including fish. An experiment was conducted to determine the acute and chronic toxicity of Cr, pH and high temperature in Anabas testudineus. Lethal concentration (LC₅₀) of Cr alone was determined as 55.02 mg L^-1, Cr and low pH 48.19 mg L^-1 and Cr, low pH and high temperature 47.16 mg L^-1. The chronic toxicity of low dose of Cr, pH and high temperature (1/10th and 1/20th of LC₅₀) was designed to execute the experiment for 72 days. The stress enzymes and biomarkers were determined viz. superoxide dismutase, catalase, glutathione peroxidase, glutathione-s-transferase, lipid peroxide, acetylcholine esterase, cortisol, HSP-70, blood glucose, aspartate amino transferase, alanine amino transferase and malate dehydrogenase, lactate dehydrogenase, ATPase and genotoxicity in this study. We had also studied the integrated biomarker response (IBR), which revealed that Cr toxicity enhanced with concurrent exposure to pH and high temperature. All the biochemical attributes were significantly altered with exposure to Cr alone and with low pH and high temperature except gill SOD. Further, thermal tolerance was also determined, and results revealed that thermal tolerance was significantly reduced with exposure to Cr alone and Cr and low pH exposure in A. testudineus. The present study concluded that, the chronic toxicity of Cr is enhanced with low pH and high temperature and it has led to understanding the multi-approach of Cr toxicity which affect, stress biomarkers, cellular metabolic stress and thermal tolerance of A. testudineus.

TRPM2 deficiency in mice protects against atherosclerosis by inhibiting TRPM2-CD36 inflammatory axis in macrophages

Atherosclerosis is the major cause of ischemic heart disease and stroke, the leading causes of mortality worldwide. The central pathological features of atherosclerosis include macrophage infiltration and foam cell formation. However, the detailed mechanisms regulating these two processes remain unclear. Here we show that oxidative stress-activated Ca²⁺-permeable transient receptor potential melastatin 2 (TRPM2) plays a critical role in atherogenesis. Both global and macrophage-specific Trpm2 deletion protect Apoe^−/− mice against atherosclerosis. Trpm2 deficiency reduces oxidized low-density lipoprotein (oxLDL) uptake by macrophages, thereby minimizing macrophage infiltration, foam cell formation and inflammatory responses. Activation of the oxLDL receptor CD36 induces TRPM2 activity, and vice versa. In cultured macrophages, TRPM2 is activated by CD36 ligands oxLDL and thrombospondin-1 (TSP1), and deleting Trpm2 or inhibiting TRPM2 activity suppresses the activation of CD36 signaling cascade induced by oxLDL and TSP1. Our findings establish the TRPM2-CD36 axis as a molecular mechanism underlying atherogenesis, and suggest TRPM2 as a potential therapeutic target for atherosclerosis.

RNA N6-methyladenosine modulates endothelial atherogenic responses to disturbed flow in mice

Atherosclerosis preferentially occurs in atheroprone vasculature where human umbilical vein endothelial cells are exposed to disturbed flow. Disturbed flow is associated with vascular inflammation and focal distribution. Recent studies have revealed the involvement of epigenetic regulation in atherosclerosis progression. N6-methyladenosine (m6A) is the most prevalent internal modification of eukaryotic mRNA, but its function in endothelial atherogenic progression remains unclear. Here, we show that m6A mediates the epidermal growth factor receptor (EGFR) signaling pathway during EC activation to regulate the atherosclerotic process. Oscillatory stress (OS) reduced the expression of methyltransferase like 3 (METTL3), the primary m6A methyltransferase. Through m6A sequencing and functional studies, we determined that m6A mediates the mRNA decay of the vascular pathophysiology gene EGFR which leads to EC dysfunction. m6A modification of the EGFR 3' untranslated regions (3'UTR) accelerated its mRNA degradation. Double mutation of the EGFR 3'UTR abolished METTL3-induced luciferase activity. Adenovirus-mediated METTL3 overexpression significantly reduced EGFR activation and endothelial dysfunction in the presence of OS. Furthermore, thrombospondin-1 (TSP-1), an EGFR ligand, was specifically expressed in atheroprone regions without being affected by METTL3. Inhibition of the TSP-1/EGFR axis by using shRNA and AG1478 significantly ameliorated atherogenesis. Overall, our study revealed that METTL3 alleviates endothelial atherogenic progression through m6A-dependent stabilization of EGFR mRNA, highlighting the important role of RNA transcriptomics in atherosclerosis regulation.

An Overview of Glycosylation and its Impact on Cardiovascular Health and Disease

The cardiovascular system is a complex and well-organized system in which glycosylation plays a vital role. The heart and vascular wall cells are constituted by an array of specific receptors; most of them are N- glycosylated and mucin-type O-glycosylated. There are also intracellular signaling pathways regulated by different post-translational modifications, including O-GlcNAcylation, which promote adequate responses to extracellular stimuli and signaling transduction. Herein, we provide an overview of N-glycosylation and O-glycosylation, including O-GlcNAcylation, and their role at different levels such as reception of signal, signal transduction, and exogenous molecules or agonists, which stimulate the heart and vascular wall cells with effects in different conditions, like the physiological status, ischemia/reperfusion, exercise, or during low-grade inflammation in diabetes and aging. Furthermore, mutations of glycosyltransferases and receptors are associated with development of cardiovascular diseases. The knowledge on glycosylation and its effects could be considered biochemical markers and might be useful as a therapeutic tool to control cardiovascular diseases.

TSP-1 (Thrombospondin-1) Deficiency Protects ApoE-/- Mice Against Leptin-Induced Atherosclerosis

OBJECTIVE

Hyperleptinemia, hallmark of obesity, is a putative pathophysiologic trigger for atherosclerosis. We previously reported a stimulatory effect of leptin on TSP-1 (thrombospondin-1) expression, a proatherogenic matricellular protein implicated in atherogenesis. However, a causal role of TSP-1 in leptin-driven atherosclerosis remains unknown. Approach and Results: Seventeen-weeks-old ApoE-/- and TSP-1-/-/ApoE-/- double knockout mice, on normocholesterolemic diet, were treated with or without murine recombinant leptin (5 µg/g bwt, IP) once daily for 3 weeks. Using aortic root morphometry and en face lesion assay, we found that TSP-1 deletion abrogated leptin-stimulated lipid-filled lesion burden, plaque area, and collagen accumulation in aortic roots of ApoE-/- mice, shown via Oil red O, hematoxylin and eosin, and Masson trichrome staining, respectively. Immunofluorescence microscopy of aortic roots showed that TSP-1 deficiency blocked leptin-induced inflammatory and smooth muscle cell abundance as well as cellular proliferation in ApoE-/- mice. Moreover, these effects were concomitant to changes in VLDL (very low-density lipoprotein)-triglyceride and HDL (high-density lipoprotein)-cholesterol levels. Immunoblotting further revealed reduced vimentin and pCREB (phospho-cyclic AMP response element-binding protein) accompanied with augmented smooth muscle-myosin heavy chain expression in aortic vessels of leptin-treated double knockout versus leptin-treated ApoE-/-; also confirmed in aortic smooth muscle cells from the mice genotypes, incubated ± leptin in vitro. Finally, TSP-1 deletion impeded plaque burden in leptin-treated ApoE-/- on western diet, independent of plasma lipid alterations.

CONCLUSIONS

The present study provides evidence for a protective effect of TSP-1 deletion on leptin-stimulated atherogenesis. Our findings suggest a regulatory role of TSP-1 on leptin-induced vascular smooth muscle cell phenotypic transition and inflammatory lesion invasion. Collectively, these results underscore TSP-1 as a potential target of leptin-induced vasculopathy.

The New Frontier of Host-Directed Therapies for Mycobacterium avium Complex

Mycobacterium avium complex (MAC) is an increasingly important cause of morbidity and mortality, and is responsible for pulmonary infection in patients with underlying lung disease and disseminated disease in patients with AIDS. MAC has evolved various virulence strategies to subvert immune responses and persist in the infected host. Current treatment for MAC is challenging, requiring a combination of multiple antibiotics given over a long time period (for at least 12 months after negative sputum culture conversion). Moreover, even after eradication of infection, many patients are left with residual lung dysfunction. In order to address similar challenges facing the management of patients with tuberculosis, recent attention has focused on the development of novel adjunctive, host-directed therapies (HDTs), with the goal of accelerating the clearance of mycobacteria by immune defenses and reducing or reversing mycobacterial-induced lung damage. In this review, we will summarize the evidence supporting specific adjunctive, HDTs for MAC, with a focus on the repurposing of existing immune-modulatory agents targeting a variety of different cellular pathways. We also highlight areas meriting further investigation.

Acacetin Protects Against High Glucose-Induced Endothelial Cells Injury by Preserving Mitochondrial Function via Activating Sirt1/Sirt3/AMPK Signals

The strategy of decreasing atherosclerotic cardiovascular disorder is imperative for reducing premature death and improving quality of life in patients with diabetes mellitus. The aim of this study was to investigate whether the natural flavone acacetin could protect against endothelial injury induced by high glucose and attenuate diabetes-accelerated atherosclerosis in streptozotocin-(STZ) induced diabetic ApoE^−/− mice model. It was found that in human umbilical vein endothelial cells (HUVECs) cultured with normal 5.5 mM or high 33 mM glucose, acacetin (0.3–3 μM) exerted strong cytoprotective effects by reversing high glucose-induced viability reduction and reducing apoptosis and excess production of intracellular reactive oxygen species (ROS) and malondialdehyde in a concentration-dependent manner. Acacetin countered high glucose-induced depolarization of mitochondrial membrane potential and reduction of ATP product and mitoBcl-2/mitoBax ratio. Silencing Sirt3 abolished the beneficial effects of acacetin. Further analysis revealed that these effects of acacetin rely on Sirt1 activation by increasing NAD⁺ followed by increasing Sirt3, pAMPK and PGC-1α. In STZ-diabetic mice, acacetin significantly upregulated the decreased signaling molecules (i.e. SOD, Bcl-2, PGC-1α, pAMPK, Sirt3 and Sirt1) in aorta tissue and attenuated atherosclerosis. These results indicate that vascular endothelial protection of acacetin by activating Sirt1/Sirt3/AMPK signals is likely involved in alleviating diabetes-accelerated atherosclerosis by preserving mitochondrial function, which suggests that acacetin may be a drug candidate for treating cardiovascular disorder in patients with diabetes.

The effects of chromium picolinate on glucose and lipid metabolism in running rats

BACKGROUND

Chromium picolinate (CrPic) is commonly used to reduce muscle fatigue after exercise. We aimed to elucidate the effects of CrPic on glucose and lipid metabolism and the expression of glucose transporters in exercised rats.

METHODS

Forty-two male Wistar rats (8-week-old) were distributed into six groups (n = 7) as follows: Control, CrPic, Chronic Exercise (CEx), CEx + CrPic, Acute Exercise (AEx), and AEx + CrPic. CEx consists of 30 m/min, 30 min/day, and 5 days/week for 6 weeks. CrPic was supplemented at 400 μg elemental Cr/kg of diet for 6 weeks. In the AEx groups, animals were run on the treadmill at 30 m/min until exhaustion.

RESULTS

CEx significantly lowered blood glucose (BG), total cholesterol (TC) and triglyceride (TG) levels, but elevated insulin concentration (IC), compared with control (P < 0.05). CEx significantly decreased the level of malondialdehyde (MDA) in the serum, liver, and muscle while AEx elevated it (P < 0.001 for all). CrPic significantly decreased BG, TC, TG levels, and increased IC with a remarkable effect in CEx rats (P < 0.01). CrPic also significantly reduced serum, liver, and muscle MDA levels (P < 0.001). Both AEx and CEx increased the expression of liver glucose transporter 2 (GLUT-2) and muscle GLUT-4 with the highest level in CEx rats (P < 0.05). Moreover, CrPic supplementation significantly elevated GLUT-2 and GLUT-4 expressions in the liver and muscle of sedentary and exercise-treated rats (P < 0.05).

CONCLUSION

CrPic improves various metabolic parameters and reduces oxidative stress in CEx and AEx rats by decreasing BG, TC, TG, MDA levels in serum and elevating GLUT-2 and GLUT-4 expression in the liver and muscle samples. The efficacy of CrPic was more pronounced in CEx rats.

Role of thrombospondin‑1 and thrombospondin‑2 in cardiovascular diseases (Review)

Thrombospondin (TSP)-1 and TSP-2 are matricellular proteins in the extracellular matrix (ECM), which serve a significant role in the pathological processes of various cardiovascular diseases (CVDs). The multiple effects of TSP-1 and TSP-2 are due to their ability to interact with various ligands, such as structural components of the ECM, cytokines, cellular receptors, growth factors, proteases and other stromal cell proteins. TSP-1 and TSP-2 regulate the structure and activity of the aforementioned ligands by interacting directly or indirectly with them, thereby regulating the activity of different types of cells in response to environmental stimuli. The pathological processes of numerous CVDs are associated with the degradation and remodeling of ECM components, and with cell migration, dysfunction and apoptosis, which may be regulated by TSP-1 and TSP-2 through different mechanisms. Therefore, investigating the role of TSP-1 and TSP-2 in different CVDs and the potential signaling pathways they are associated with may provide a new perspective on potential therapies for the treatment of CVDs. In the present review, the current understanding of the roles TSP-1 and TSP-2 serve in various CVDs were summarized. In addition, the interacting ligands and the potential pathways associated with these thrombospondins in CVDs are also discussed.

Thrombospondin-1: A Key Protein That Induces Fibrosis in Diabetic Complications

Fibrosis accompanies most common pathophysiological features of diabetes complications in different organs. It is characterized by an excessive accumulation of extracellular matrix (ECM) components, the response to which contributes to inevitable organ injury. The extracellular protein thrombospondin-1 (TSP-1), a kind of extracellular glycoprotein, is upregulated by the increased activity of some transcription factors and results in fibrosis by activating multiple pathways in diabetes. The results of studies from our team and other colleagues indicate that TSP-1 is associated with the pathological process leading to diabetic complications and is considered to be the most important factor in fibrosis. This review summarizes the molecular mechanism of increased TSP-1 induced by hyperglycemia and the role of TSP-1 in fibrosis during the development of diabetes complications.

Chromium speciation by isophthalic acid-doped polymer dots as sensitive and selective fluorescent probes

Hexavalent chromium is a known carcinogen, among all species of chromium ions, for the respiratory tract in humans. In the present work, a new facile probe is developed for rapid and sensitive determination of Cr(VI) based on utilizing highly fluorescent conjugated poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-co-(1,4-benzo-(2,1',3) thiadiazole)] (PFBT) polymer dots (PDs). The PDs are easily functionalized by doping of isophthalic acid (IPA) into the target PDs during a single step preparation. The prepared PDs with an average diameter of 30 nm illustrated a strong fluorescence with an emission peak centered at 530 nm (photo-excited at 480 nm). The strong fluorescence of PDs is selectively and significantly quench with Cr(VI), while it does not change by Cr(III) ion and, thus, can facilitate a chromium speciation process. The proposed mechanism is an inner filter effect (IFE) mechanism, in which the absorption bands of Cr(IV) overlaps with the emission and excitation bands of the modified PDs. The prepared PDs revealed a good linear relationship from 0.1 to 1000 μmol L^-1 for Cr(VI) with a detection limit of 0.03 μmol L^-1, which further used to track the Cr distribution in water samples. Finally, the IPA-doped PDs with excellent optical properties, biocompatibility, and high quantum yield showed promising potential in tracking Cr species and specifying of different Cr ions inside the human cells, which opening a new door toward getting a better insight into the cell function and metabolism in the presence of heavy metal ions, and especially chromium ions.

Influence of Chronic Toxicity, Lipid Metabolism, Learning and Memory Ability, and Related Enzyme in Sprague-Dawley Rats by Long-Term Chromium Malate Supplementation

In our previous study, chromium malate is beneficial for type 2 diabetic rats in control glycometabolism and lipid metabolism. The present study was designed to observe the chronic toxicity, lipid metabolism, learning and memory ability, and related enzymes of chromium malate in rats during the year. The results showed that pathological, toxic, feces, and urine of chromium malate (at daily doses of 10.0, 15.0, and 20.0 μg Cr/kg bm) did not change measurably. Chromium malate (at daily doses of 15.0 and 20.0 μg Cr/kg bm) could significantly reduce the levels of total cholesterol (TC), LDL, and triglyceride (TG), and increase the level of HDL in male rats compared to control group and chromium picolinate group. Significant escalating trends of the escape latency and swimming speed (Morris water maze test), and the original platform quadrant stops, residence time, and swimming speed (Space exploration test) in male rats of chromium malate groups were obtained. The SOD, GSH-Px, and TChE activities of chromium malate (at daily doses of 15.0 and 20.0 μg Cr/kg bm) were enhanced significantly in male rats compared with those of the normal control group and chromium picolinate group. Glycometabolism and related enzymes had no significant changes compared to normal control group and chromium picolinate group. These results indicated that long-term chromium malate supplementation did not cause measurable toxicity at daily doses of 10.0, 15.0, and 20.0 μg Cr/kg bm and could improve dyslipidemia and learning and memory deficits.