Diabetes and advanced glycoxidation end products

Dietary preferences and diabetic risk in China: A large-scale nationwide Internet data-based study

BACKGROUND

Unhealthy diet is one of the important risk factors of diabetes, which is one of the major public health problems in China. The Internet tools provide large-scale passively collected data that show people's dietary preferences and their relationship with diabetes risk.

METHODS

212 341 708 individuals' dietary preference labels were created based on Internet data from online search and shopping software. Metabolic data obtained from the 2010 China Noncommunicable Disease Surveillance, which had 98 658 participants, was used to estimate the relation between dietary preferences geographical distribution and diabetes risk.

RESULTS

Chinese dietary preferences had different geographical distribution, which is related to the local climate and consumption level. Fried food preference proportion distribution was significantly positively correlated with diabetes prevalence, hypertension prevalence and body mass index (BMI). Similarly, grilled food preference proportion distribution had significantly positive correlation with the prevalence of diabetes and hypertension. In contrast, spicy food preference proportion distribution was negatively correlated with diabetes prevalence. Sweet food preference proportion distribution was positively related to diabetes prevalence. Using dietary preferences data to predict regional prevalence of diabetes, hypertension and BMI, the average values of error (95% CI) between the three paired predicted and observed values were 9.8% (6.9%-12.7%), 7.5% (5.0%-10.0%) and 1.6% (1.2%-2.0%), respectively.

CONCLUSIONS

Fried food, grilled food, and sweet food preferences were positively related to diabetes risk whereas spicy food preference was negatively correlated with diabetes risk. Dietary preferences based on passively collected Internet data could be used to predict regional prevalence of diabetes, hypertension, and BMI and showed good value for public health monitoring.

Enhanced oral bioavailability and anti-diabetic activity of canagliflozin through a spray dried lipid based oral delivery: a novel paradigm

AIM

Canagliflozin (CFZ), a novel SGLT II antagonist, exhibits erratic absorption after oral administration. The current study entails development and evaluation of spray dried lipid based formulation (solid SMEDDS) for enhancing oral bioavailability and anti-diabetic activity of CFZ.

METHODS

Solid SMEDDS developed through spray drying containing Neusilin US2 as an adsorbent. The formed solid SMEDDS were characterized for physicochemical and solid state attributes. Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) were used to confirm the spherical morphology. In vitro dissolution, ex vivo permeability and in vivo pharmacokinetic studies were conducted to determine the release rate, permeation rate and absorption profile of CFZ, respectively. Pharmacodynamic studies were done as per standard protocols.

RESULTS

The optimized solid SMEDDS exhibited acceptable practical yield and flow properties and is vouched with enhanced amorphization, nanoparticulate distribution and acceptable drug content. The spherical morphology of solid SMEDDS and reconstituted SMEDDS were confirmed in SEM and TEM, respectively. In vitro dissolution studies revealed multi-fold release behavior in CFZ in various dissolution media, whereas, remarkable permeability was observed in jejunum segment of rat intestine. Pharmacokinetic studies of CFZ in solid SMEDDS demonstrated 2.53 and 1.43 fold enhancement in C_max and 2.73 and 1.98 fold in AUC _0-24h, as compared to pure API and marketed formulation, respectively. Pharmacological evaluation of solid SMEDDS revealed enhanced anti-diabetic activity of CFZ through predominant SGLT II inhibition in rats, as evident from evaluation of biochemical levels, urinary glucose excretion studies and SGLT II expression analysis.

CONCLUSION

The current work describes significant improvement biopharmaceutical properties of CFZ in solid SMEDD formulation. Graphical abstract Graphical Abstract: Enhanced oral bioavailability and anti-diabetic activity of canagliflozin through a spray dried lipid based oral delivery: a novel paradigm.

Mitochondrial carnitine palmitoyltransferase 2 is involved in Nε-(carboxymethyl)-lysine-mediated diabetic nephropathy

Diabetic nephropathy (DN) is the most common cause of end-stage renal disease in the world. Advanced glycation end products (AGEs) are thought to be involved in the pathogenesis of DN via multifactorial mechanisms including the generation of oxidative stress and overproduction of various growth factors and cytokines. AGEs are heterogeneous cross-linked sugar-derived proteins, and N^ε-(carboxymethyl)-lysine (CML)-conjugated BSA is a major component of AGEs. However, the proteins involved in DN induction by CML have never been reported. Herein, we investigated specific protein regulators of AGE-mediated DN via proteomic analysis of streptozotocin (STZ)-induced diabetic mice kidneys. We identified 937, 976, and 870 proteins in control, STZ, and STZ + CML-BSA samples, respectively. Bioinformatics analysis identified several CML-mediated proteins potentially involved in kidney damage, activation of fatty acid oxidation (FAO), and mitochondrial dysfunction. Furthermore, we identified the CML-specific differential protein carnitine palmitoyltransferase 2 (CPT2), related to FAO. To confirm the effect of CPT2 and the CML-mediated mechanism, human renal tubular HK-2 cells were treated with CML-BSA and cpt2 siRNA, and examined for FAO-mediated fibrosis and mitochondrial dysfunction. CML-BSA and CPT2 knockdown induced fibrosis-related gene expression and damage to mitochondrial membrane potential. Moreover, CPT2 overexpression recovered CML-induced fibrosis-related gene expression. Based on these results, a decrease in CML-induced CPT2 expression causes mitochondrial FAO damage, leading to renal fibrosis and DN.

Potential effect of advanced glycation end products (AGEs) on spermatogenesis and sperm quality in rodents

The aim of the present study was to assess whether dietary advanced glycation end products (AGEs) induce testicular dysfunction. Using a BALB/c mouse model, AGE intake and serum levels were found to increase in AGE diet-treated mice relative to the controls. Histopathological damage was detected in the testes and epididymides of the AGE diet-induced mice. The total number of epididymal sperm decreased, and increased abnormal sperm rate was found in the mice. Moreover, the mice testes showed an increased level of the receptor for AGEs (RAGE) and malondialdehyde (MDA). Using a Sprague-Dawley rat model, AGE diet-induced rats showed 3- to 4-fold higher AGE intake than the controls. In these rats, higher serum and sperm MDA levels, decreased epididymal sperm numbers, and increased abnormal sperm rates were also observed. Silymarin, a natural AGE inhibitor, was found to restore these AGE-induced phenomena. Concluding from the above findings, dietary AGEs may promote testicular dysfunction.

Antidiabetic and Antihyperlipidemic Effects of Sulphurenic Acid, a Triterpenoid Compound from Antrodia camphorata, in Streptozotocin-Induced Diabetic Mice

The present study was designed to evaluate the protective effect of sulphurenic acid (SA), a pure compound from Antrodia camphorata, on diabetes and hyperlipidemia in an animal model study and to clarify the underlying molecular mechanism. Diabetes was induced by daily 55 mg/kg intraperitoneal injections of streptozotocin (STZ) solution over five days. Diabetic mice were randomly divided into six groups and orally gavaged with SA (at three dosages) or glibenclamide (Glib), fenofibrate (Feno) or vehicle for 3 weeks. Our findings showed that STZ-induced diabetic mice had significantly increased fasting blood glucose, glycated hemoglobin (HbA1C), plasma triglyceride (TG), and total cholesterol (TC) levels (p < 0.001, p < 0.001, p < 0.001, and p < 0.05, respectively) but decreased blood insulin, adiponectin, and leptin levels compared to those of the control group (p < 0.001, p < 0.001, and p < 0.001, respectively). Administration of SA to STZ-induced diabetic mice may lower blood glucose but it increased the insulin levels with restoration of the size of the islets of Langerhans cells, implying that SA protected against STZ-induced diabetic states within the pancreas. At the molecular level, SA treatment exerts an increase in skeletal muscle expression levels of membrane glucose transporter 4 (GLUT4) and phospho-Akt to increase the membrane glucose uptake, but the mRNA levels of PEPCK and G6Pase are decreased to inhibit hepatic glucose production, thus leading to its hypoglycemic effect. Moreover, SA may cause hypolipidemic effects not only by enhancing hepatic expression levels of peroxisome proliferator-activated receptor α (PPARα) with increased fatty acid oxidation but also by reducing lipogenic fatty acid synthase (FAS) as well as reducing mRNA levels of sterol regulatory element binding protein (SREBP)1C and SREBP2 to lower blood TG and TC levels. Our findings demonstrated that SA displayed a protective effect against type 1 diabetes and a hyperlipidemic state in STZ-induced diabetic mice.

Contribution of Oxidative Stress and Impaired Biogenesis of Pancreatic β-Cells to Type 2 Diabetes

Significance: Type 2 diabetes development involves multiple changes in β-cells, related to the oxidative stress and impaired redox signaling, beginning frequently by sustained overfeeding due to the resulting lipotoxicity and glucotoxicity. Uncovering relationships among the dysregulated metabolism, impaired β-cell "well-being," biogenesis, or cross talk with peripheral insulin resistance is required for elucidation of type 2 diabetes etiology. Recent Advances: It has been recognized that the oxidative stress, lipotoxicity, and glucotoxicity cannot be separated from numerous other cell pathology events, such as the attempted compensation of β-cell for the increased insulin demand and dynamics of β-cell biogenesis and its "reversal" at dedifferentiation, that is, from the concomitantly decreasing islet β-cell mass (also due to transdifferentiation) and low-grade islet or systemic inflammation. Critical Issues: At prediabetes, the compensation responses of β-cells, attempting to delay the pathology progression-when exaggerated-set a new state, in which a self-checking redox signaling related to the expression of Ins gene expression is impaired. The resulting altered redox signaling, diminished insulin secretion responses to various secretagogues including glucose, may lead to excretion of cytokines or chemokines by β-cells or excretion of endosomes. They could substantiate putative stress signals to the periphery. Subsequent changes and lasting glucolipotoxicity promote islet inflammatory responses and further pathology spiral. Future Directions: Should bring an understanding of the β-cell self-checking and related redox signaling, including the putative stress signal to periphery. Strategies to cure or prevent type 2 diabetes could be based on the substitution of the "wrong" signal by the "correct" self-checking signal.

Selected elements of extracellular matrix of the skin in diabetes and insulin resistance

PURPOSE

Reconstruction of the skin extracellular matrix is a physiological phenomenon occurring on a continuous basis. The aim of this study is to evaluate the content of basic enzymes preventing oxidative stress: superoxide dismutase 2 and 3 as well as catalase, the content of hyaluronic acid, and the activity of N-acetyl-β-d-hexosaminidase and β-d-glucuronidase in the skin of rats used as animal models of diabetes and insulin resistance, before and after the treatment.

MATERIALS AND METHODS

The study was conducted on a group of sexually mature male Wistar rats divided into 7 groups of 10 animals. Insulin resistance was induced by feeding the rats with a high-fat diet, and diabetes was induced by a single injection of streptozotocin. Chosen groups of rats were treated with insulin or metformin. After 8 weeks, we excised a fragment of shaved dorsal skin from anesthetized rats in each group.

RESULTS

In the course of diabetes and insulin resistance, an intensified defensive activity of cells against the oxidative stress was observed in the undamaged skin, expressed by an increase in the relative content of superoxide dismutase 2 and 3, catalase and the activity of N-acetyl-β-d-hexosaminidase and β-d-glucuronidase. Diabetes and insulin resistance cause similar skin damage, as there are no differences in the relative contents or specific activities of the examined parameters.

CONCLUSIONS

Insulin and metformin improve the quality of the skin in rats with diabetes and insulin resistance, by restoring the content of hyaluronic acid to the healthy skin level.

Specific Inhibition of CYP4A Alleviates Myocardial Oxidative Stress and Apoptosis Induced by Advanced Glycation End-Products

High exposure to advanced glycation end-products (AGEs) may induce cardiotoxicity. However, the effects and mechanisms remain to be further clarified. CYP4A plays an important role in the pathophysiological process of myocardial abnormalities by modulating oxidative stress and apoptosis (OS/Apop) signaling pathway. The present work aimed to investigate whether CYP4A mediates AGEs-induced myocardial injury. AGEs solution was administered intragastrically to C57BL/6 mice for 60 days, while the specific inhibitor of CYP4A, HET0016, was given from the 47th day via intraperitoneal injection for 2 weeks. Levels of OS/Apop in heart tissue were measured. The effects on the cell viability and apoptosis were detected in primary rat cardiomyocytes. To further investigate the mechanism, H9c2 cells were treated with HET0016 or small interfering RNAs (siRNAs) against CYP4a mRNA before incubation with AGEs. Exposure to AGEs led to significantly increased expression of CYP4A and levels of OS/Apop in heart and H9c2 cells both in vivo and in vitro. The OS/Apop pathway was activated with increased expression of NOX2, p-JNK, and cleaved caspase-3 (c-caspase-3) and decreased expression of p-Akt and Bcl-xL both in vivo and in vitro. Specific CYP4A suppression by HET0016 or siRNA exerted significant protective effects by attenuating AGEs-induced OS/Apop pathways in vitro. Our results demonstrate that specific inhibition of CYP4A might be a potential therapeutic option for myocardial injury induced by AGEs.

Receptor for Advanced Glycation End Products Antagonism Blunts Kidney Damage in Transgenic Townes Sickle Mice

A large proportion of adult patients with sickle cell disease (SCD) develops kidney disease and is at a high risk of mortality. The contribution of advanced glycation end products and their receptor (AGE/RAGE) axis has been established in the pathogenesis of multiple kidney diseases. The aim of the present study was to determine the implication of RAGE in the development of SCD-related kidney complications in a mouse model of SCD, as this has never been investigated. 8-week-old AA (normal) and SS (homozygous SCD) Townes mice were treated with a specific RAGE antagonist (RAP) or vehicle (NaCl). After 3 weeks of treatment, red blood cell count, hematocrit, and hemoglobin levels were significantly higher in RAP-treated SS mice. Reticulocyte count and sickle cell count were reduced in RAP-SS compared to their NaCl-treated littermates. The lower NADPH oxidase activity in the kidney of RAP-treated mice compared to NaCl-treated mice suggests limited ROS production. RAP-treated SS mice had decreased NF-κB protein expression and activation as well as reduced TNF-α mRNA expression in the kidney. Glomerular area, interstitial fibrosis, tubular iron deposits, and KIM-1 protein expression were significantly reduced after RAP treatment. In conclusion, this study provides evidence supporting the pathogenic role of RAGE in kidney injuries in sickle cell mice.

(De)Toxifying the Epigenetic Code

Cells are continuously subjected to an array of reactive/toxic chemical species which are produced both endogenously through metabolic pathways and taken up exogenously by diet and exposure to drugs or toxins. As a result, proteins often undergo non-enzymatic covalent modifications (NECMs) by these species, which can alter protein structure, function, stability, and binding partner affinity. NECMs accumulate over time and are linked to various diseases such as Alzheimer's disease, cancer, and diabetes. In the cellular proteome, histones have some of the longest half-lives, making them prime targets for NECMs. In addition, histones have emerged as key regulators of transcription, a function that is primarily controlled by modification of their tails. These modifications are usually installed or removed enzymatically, but recent evidence suggests that some may also occur non-enzymatically. Despite the vast knowledge detailing the relationship between histone modifications and gene regulation, NECMs on histones remain poorly explored. A major reason for this difference stems from the fact that, unlike their enzymatically installed counterparts, NECMs are difficult to both control and test in vivo. Here, we review advances in our understanding of the effect non-enzymatic covalent modifications (NECMs) have on the epigenetic landscape, cellular fate, and their implications in disease. Cumulatively, this illustrates how the epigenetic code is directly toxified by chemicals and detoxified by corresponding eraser enzymes.

Advanced Glycation End Products in Chinese Medicine Mediated Aging Diseases: A Review

Aging has become a worldwide problem. During this process, the incidence of related diseases such as diabetes and atherosclerosis increases dramatically. Studies within the most recent two decades suggest a pivotal role of Advanced Glycation End Products (AGEs) in the aging process. This review aims to systemically summarize the effects and potential mechanism of Chinese Medicines on inhibiting AGEs-related aging diseases.

Comparison of the effect of two therapeutic exercises on the inflammatory and physiological conditions and complications of diabetic neuropathy in female patients

INTRODUCTION AND AIM

The purpose of this study was to compare the effect of 12 weeks of low-intensity resistance training and exercises for peripheral neuropathy (EPN) on the inflammatory and physiological conditions, balance, and complications of diabetic neuropathy in female patients.

MATERIALS AND METHODS

45 women with mild to moderate diabetic neuropathy and an average age of 55.46±3.06 years voluntarily participated in the study. They were randomly assigned to either control (n=15), resistance (n=15), and EPN (n=15) groups. Both experimental groups were trained for 12 weeks (three sessions per week). EPN group did peripheral neuropathic exercises (12 lower extremity movements), and the resistance group performed their exercises with a 30% repetition maximum. During the intervention period, the control group only performed their daily activities. Blood samples were taken in both pre-test and post-test to investigate the levels of Tumor necrosis-α (TNF-α), Interleukin-10 (IL-10), C Reactive Protein (CRP), fast blood glucose (FBG) and Glycated hemoglobin (HbA1c). Complications of diabetic neuropathy were measured using the Michigan questionnaire and the Monofilament 10 g. In order to measure the balance, De Morton mobility index (DEMMI) was used.

RESULTS

The statistical analyses showed a significant decrease of FBG and HbA1c in the two experimental groups, as compared to the control group. TNF-α and CRP levels were decreased in both EPN and resistance groups, as compared to the control group. The observed increase in the serum IL-10 levels of the two experimental groups was not, however, significant, as shown in intra-group and inter-group comparisons. On the other hand, the two complications of pain and tingling in the lower limb extremities were improved in both experimental groups (p<0.05). However, the numbness complication showed no significant change (p=0.10). Static and dynamic balance was improved in the EPN group as well (p<0.05).

CONCLUSION

Since EPN exercises, in contrast to resistance exercises, are focused on the lower limb extremities and designed for diabetic neuropathy patients, they can improve the imbalance, pain and tingling, by significantly reducing TNF-α and CRP and improving the physiological conditions.

Essential but sparse collagen hydroxylysyl post-translational modifications detected by DNP NMR

The sparse but functionally essential post-translational collagen modification 5-hydroxylysine can undergo further transformations, including crosslinking, O-glycosylation, and glycation. Dynamic nuclear polarization (DNP) and stable isotope enriched lysine incorporation provide sufficient solid-state NMR sensitivity to identify these adducts directly in skin and vascular smooth muscle cell extracellular matrix (ECM), without extraction procedures, by comparison with chemical shifts of model compounds. Thus, DNP provides access to the elucidation of structural consequences of collagen modifications in intact tissue.

Immune and vascular dysfunction in diabetic wound healing

The diminished capacity for wound healing in patients with diabetes contributes to morbidity through ulceration and recurrent infections, loss of function and decreased workplace productivity, increased hospitalisation rates, and rising health-care costs. These are due to diabetes' effects on signalling molecules, cellular cascades, different cell populations, and the vasculature. The function of multiple immune system components including cellular response, blood factors, and vascular tone are all negatively impacted by diabetes. The purpose of this paper is to review the current understanding of immune and vascular dysfunction contributing to impaired wound healing mechanisms in the diabetic population. Normal wound healing mechanisms are reviewed followed by diabetic aberrations to immune and inflammatory function and atherogenesis and angiopathy.

DECLARATION OF INTEREST

The authors have no financial or personal relationships to people or organisations that could potentially and inappropriately influence their work and conclusions.

Autocatalytic cycle in the pathogenesis of diabetes mellitus: biochemical and pathophysiological aspects of metabolic therapy with natural amino acids on the example of glycine

In this work systematization (classification) of biochemical and physiological processes that cause disorders in the human body during the development of diabetes mellitus is carried out. The development of the disease is considered as the interaction and mutual reinforcement of two groups of parallel processes. The first group has a molecular nature and it is associated with impairment of ROS-regulation system which includes NADPH oxidases, RAGE receptors, mitochondria, cellular peroxireductase system and the immune system. The second group has a pathophysiological nature and it is associated with impairment of microcirculation and liver metabolism. The analysis of diabetes biochemistry based on different published references yields a creation of a block diagram evaluating the disease development over time. Two types of autocatalytic processes were identified: autocatalysis in the cascade of biochemical reactions and "cross-section" catalysis, in which biochemical and pathophysiological processes reinforce each other. The developed model has shown the possibility of using pharmacologically active natural metabolite glycine as a medicine inhibiting the development of diabetes. Despite the fact that glycine is a substitute amino acid the drop in the glycine blood concentration occurs even in the early stages of diabetes development and can aggravate the disease. It is shown that glycine is a potential blocker of key autocatalytic cycles, including biochemical and pathophysiological processes. The analysis of the glycine action based on the developed model is in complete agreement with the results of clinical trials in which glycine has improved blood biochemistry of diabetic patients and thereby it prevents the development of diabetic complications.

Fighting diabetic foot ulcers-The diabetologist: A king maker of the fight

Diabetic foot ulcer is a costly and serious complication of diabetes mellitus and is the major cause of non-traumatic limb amputations worldwide. Its development is primarily the result of diabetic neuropathy and/or peripheral arterial disease with accompanied bone abnormalities and is complicated by invasive infection. The management of this clinical condition focuses on identification of the "at-risk" foot, treatment of the ulcerated foot, and prevention of further complications. As diabetic foot ulcer represents the sum of multiple etiologies, its treatment requires a multidisciplinary team, which can result in a significant reduction in the incidence of ulcers, infections and amputations. The team should include a diabetologist, a podiatrist, an orthoptist, an educator and a plaster technician, in close collaboration with a vascular surgeon, an orthopedic/podiatric surgeon and a dermatologist. It is recommended that a diabetologist be the multidisciplinary team leader, as diabetic foot ulcer is a complication of diabetes and chronic hyperglycemia represents the main cause for its development. The appropriate composition of professionals involved in the team is institution-dependent and may vary worldwide, depending on the diabetic population. The concept of establishing a diabetic foot care team is recommended by all National and International Diabetes Scientific Societies and Associations.

Mechanism of action of camphoryl-benzene sulfonamide derivative on glucose uptake in adipose tissue

The aim of the present study was to investigate the mechanism of action of a sulfonamide derivative on glucose uptake in adipose tissue, as well as to characterize the effects of this compound on intestinal disaccharidases and advanced glycation end-products (AGEs) formation. Camphoryl-benzene sulfonamide (CS) was able to stimulate glucose uptake in isolated adipocytes, adipose tissue, and in soleus muscle. The stimulatory effect of the compound (10 μM) on glucose uptake on adipose tissue was blocked by diazoxide, wortmannin, U73122, colchicine, and N-ethylmaleimide. On the other hand, the effects of CS were not blocked by glibenclamide, an inhibitor of the K⁺ -ATP channel, or even by the inhibitor of protein p38 MAPK, SB 203580. In vivo, this compound reduced intestinal disaccharidase activity, while, in vitro, CS reduced the formation of AGEs at 7, 14, and 28 days of incubation. The stimulatory effect of CS on glucose uptake requires the activation of the K⁺ -ATP channel, translocation, and fusion of GLUT4 vesicles to the plasma membrane on adipocytes for glucose homeostasis. In addition, the inhibition of disaccharidase activity contributes to the glucose homeostasis in a short-term as well as the remarkable reduction in AGE formation indicates that the CS may prevent of complications of late diabetes.

Preterm Delivery and Future Risk of Maternal Cardiovascular Disease: A Systematic Review and Meta-Analysis

Background

Preterm delivery (<37 weeks gestational age) affects 11% of all pregnancies, but data are conflicting whether preterm birth is associated with long‐term adverse maternal cardiovascular outcomes. We aimed to systematically evaluate and summarize the evidence on the relationship between preterm birth and future maternal risk of cardiovascular diseases.

Methods and Results

A systematic search of MEDLINE and EMBASE was performed to identify relevant studies that evaluated the association between preterm birth and future maternal risk of composite cardiovascular disease, coronary heart disease, stroke, and death caused by cardiovascular or coronary heart disease and stroke. We quantified the associations using random effects meta‐analysis. Twenty‐one studies with over 5.8 million women, including over 338 000 women with previous preterm deliveries, were identified. Meta‐analysis of studies that adjusted for potential confounders showed that preterm birth was associated with an increased risk of maternal future cardiovascular disease (risk ratio [RR] 1.43, 95% confidence interval [CI], 1.18, 1.72), cardiovascular disease death (RR 1.78, 95% CI, 1.42, 2.21), coronary heart disease (RR 1.49, 95% CI, 1.38, 1.60), coronary heart disease death (RR 2.10, 95% CI, 1.87, 2.36), and stroke (RR 1.65, 95% CI, 1.51, 1.79). Sensitivity analysis showed that the highest risks occurred when the preterm deliveries occurred before 32 weeks gestation or were medically indicated.

Conclusions

Preterm delivery is associated with an increase in future maternal adverse cardiovascular outcomes, including a 2‐fold increase in deaths caused by coronary heart disease. These findings support the assessment of preterm delivery in cardiovascular risk assessment in women.

Antidiabetic and hypolipidemic activities of eburicoic acid, a triterpenoid compound from Antrodia camphorata, by regulation of Akt phosphorylation, gluconeogenesis, and PPARα in streptozotocin-induced diabetic mice

The study is designed to examine the potential effects and underlying mechanisms of eburicoic acid (TRR), a compound from Antrodia camphorata, in streptozotocin (STZ)-induced diabetic mice. Diabetic mice were randomly divided into six groups and given TRR orally by gavage (at three dosage rates) or fenofibrate (Feno) (250 mg kg⁻¹ body weight) or metformin (Metf) (300 mg kg⁻¹ body weight) or vehicle for 2 weeks. STZ-induced diabetic mice were found to have increased blood glucose, HbA1_C, plasma triglyceride (TG) and total cholesterol (TC) levels, but reduced blood insulin, adiponectin, and leptin levels as compared with the CON group. TRR was found to lower blood glucose and HbA1_C, but increase insulin levels. Plasma TG and TC levels were significantly lowered in TRR, Feno, or Metf-treated STZ-induced diabetic mice as compared with the vehicle-treated STZ group, indicating that TRR, Feno, and Metf ameliorated hyperlipidemia. The islet cells of STZ-induced diabetic mice exhibited a marked reduction from their classic round-shape as compared to the CON mice. The TRR-treated STZ mice revealed restoration of the size of Langerhans islet cells with β-cell repair as compared with the vehicle-treated STZ mice, implying that TRR ameliorated STZ-induced diabetic states within the pancreas. STZ-induction was found to decrease the expressions of membrane glucose transporter 4 (GLUT4), and phosphorylation of Akt in skeletal muscles, and administration of TRR reversed all the decreases. Moreover, administration of TRR increased blood insulin levels and enhanced hepatic expression levels of phospho-Akt and phospho-FoxO1 but decreased the mRNA levels of glucose-6-phosphatase (G6 Pase) and phosphoenolpyruvate carboxykinase (PEPCK) to suppress hepatic glucose production, thus leading to TRR's antidiabetic activity. Additionally, TRR caused an increase in the expression levels of fatty acid oxidation gene peroxisome proliferator-activated receptor α (PPARα), but a decrease in lipogenic fatty acid synthase (FAS) and PPARγ expressions in the liver. TRR treatment suppressed hepatic mRNA levels of sterol regulatory element binding protein (SREBP) 1c and SREBP2, leading to decreased plasma triglyceride and total cholesterol levels. These findings indicate that TRR may effectively enhance therapeutic potential in the treatment of type 1 diabetes mellitus and/or hyperlipidemia.

The study is designed to examine the potential effects and underlying mechanisms of eburicoic acid (TRR), a compound from Antrodia camphorata, in streptozotocin (STZ)-induced diabetic mice.

Polycystic ovarian syndrome-associated cardiovascular complications: An overview of the association between the biochemical markers and potential strategies for their prevention and elimination

Polycystic ovarian syndrome (PCOS) is associated with multiple cardiovascular risk factors (CVRF) including endothelial dysfunction (ED) and presence of metabolic syndrome (MS). The probable reason suggested for elevated CVRF in PCOS is oxidative stress (OS), which is an integral factor in cardiometabolic complications (CMC) seen in PCOS women. The interrelated mechanisms by which CVRF instigate clinical manifestation plays a crucial role in identification of a strategy to treat different comorbidities in PCOS. The existing treatment for PCOS mostly focuses on management of individual disorders, however, therapeutic strategies or novel targets to address cardiovascular complications in PCOS deserve extensive analysis.

The role of glycation in the pathogenesis of aging and its prevention through herbal products and physical exercise

[Purpose]

Advanced glycation end products (AGEs) are non-enzymatic modifications of proteins or lipids after exposure to sugars. In this review, the glycation process and AGEs are introduced, and the harmful effects of AGEs in the aging process are discussed.

[Methods]

Results from human and animal studies examining the mechanisms and effects of AGEs are considered. In addition, publications addressing means to attenuate glycation stress through AGE inhibitors or physical exercise are reviewed.

[Results]

AGEs form in hyperglycemic conditions and/or the natural process of aging. Numerous publications have demonstrated acceleration of the aging process by AGEs. Exogenous AGEs in dietary foods also trigger organ dysfunction and tissue aging. Various herbal supplements or regular physical exercise have beneficial effects on glycemic control and oxidative stress with a consequent reduction of AGE accumulation during aging.

[Conclusion]

The inhibition of AGE formation and accumulation in tissues can lead to an increase in lifespan.

Advanced glycation end products reduce the calcium transient in cardiomyocytes by increasing production of reactive oxygen species and nitric oxide

Advanced glycation end products (AGE) are central to the development of cardiovascular complications associated with diabetes mellitus. AGE may alter cellular function through cross‐linking of cellular proteins or by activating the AGE receptor (RAGE). However, the signalling molecules involved during AGE stimulation in cardiomyocytes remain unclear. Here, we investigated the effects of AGE treatment on intracellular calcium homeostasis of isolated cardiomyocytes and studied the activation of signalling molecules involved in this process. Treatment of cardiomyocytes with AGE for 24 h resulted in a dose‐dependent reduction in calcium transient amplitude, reaching a maximum 50% reduction at a dose of 1 mg·mL⁻¹. This was accompanied with a 32% reduction in sarcoplasmic reticulum calcium content but without any detectable changes in the expression of major calcium channels. Mechanistically, we observed a significant increase in the production of reactive oxygen species (ROS) in AGE‐treated cardiomyocytes and enhancement of NADPH oxidase activity. This was accompanied with activation of p38 kinase and nuclear translocation of NF‐κB, and subsequently induction of inducible NO synthase (iNOS) expression, leading to excessive nitric oxide production. Overall, our data reveal the molecular signalling that may underlie the alteration of intracellular calcium homeostasis in cardiac myocytes due to AGE stimulation. This may provide new insights into the pathophysiological mechanisms of the development of diabetic cardiomyopathy.

High mobility group box 1 in diabetic nephropathy

Type 2 diabetes (T2D) is a complex disorder caused by the combined effects of genetic inheritance and environmental factors. The abnormal secretion of albumin via urine is the characteristic feature of a diabetic nephropathy (DN) patient. Moreover, the detection of this observable characteristic feature of DN is quite late. As a result the time, at which DN is observable, large extent of kidney damage has already occurred. Thus, this late observation significantly decreases the chances of efficient management of DN and associated outcomes. The current biomarker used to detect DN is microalbuminuria, the presence of albumin in the urine. However, the current biomarkers often lead to false negative results. The high mobility group box (HMGB)1 is an upcoming molecule being explored for its application in the management of DN. The present review enlightens the current status of HMGB1 in DN.

Specific bioactive compounds in ginger and apple alleviate hyperglycemia in mice with high fat diet-induced obesity via Nrf2 mediated pathway

Prolonged hyperglycemia activates the formation of advanced glycation end-products (AGEs). Major dicarbonyl compounds such as methylglyoxal or glyoxal are found to be the main precursors of AGEs and N(ε)-(carboxymethyl)lysine (CML) found to be predominantly higher in the diabetic population. We hypothesized that phloretin from apple and [6]-gingerol from ginger inhibit formation of AGEs and suppress the receptor for advanced glycation end products (RAGE) via nuclear factor erythroid-2-related-factor-2 (Nrf2)-dependent pathway. Phloretin and [6]-gingerol were supplemented at two different doses to C57BL/6 mice on high fat diet or standard diet for a period of 17weeks. Phloretin or [6]-gingerol supplementation significantly reduced plasma glucose, alanine aminotransferase, aspartate aminotransferase, AGEs and insulin levels. Phloretin and [6]-gingerol also decreased the levels of AGEs and CML levels, via Nrf2 pathway, enhancing GSH/GSSG ratio, heme oxygenase-1 and glyoxalase 1 in liver tissue. These results suggest that phloretin and [6]-gingerol are potential dietary compounds that can alleviate diabetes-induced complications.

Pectin lyase-modified red ginseng extract exhibits potent anti-glycation effects in vitro and in vivo

PURPOSE

GS-E3D is a newly developed pectin lyase-modified red ginseng extract. The purpose of this study was to evaluate the inhibitory effects of GS-E3D against advanced glycation end products.

METHODS

In this study, we evaluated the inhibitory effects of GS-E3D on the formation of advanced glycation end products (AGEs) and their cross-linking with collagen in vitro and in streptozotocin-induced diabetic rats.

RESULTS

An in vitro assay for the glycation of bovine serum albumin by methylglyoxal showed that GS-E3D inhibited AGE formation at an IC50 value of 19.65 ± 4.35 μg/mL. In addition, GS-E3D showed a potent inhibitory effect (IC50 = 0.42 ± 0.08 mg/mL) on the cross-linking of AGEs with collagen. However, GS-E3D showed no effect on preformed AGEs cross-linked with collagen in the breakdown assay. To determine whether GS-E3D inhibits AGE formation and their cross-linking with proteins in vivo, streptozotocin induced diabetic rats were treated with GS-E3D (25, 50, and 100 mg/kg/day) for 6 weeks. The administration of GS-E3D decreased serum levels of AGEs and their cross linking with proteins in diabetic rats.

CONCLUSION

The inhibitory effects of this agent on advanced glycation in vitro and in vivo suggested that it may have a potential therapeutic role in controlling diabetes-induced AGE burden in various tissues.

Consumption of diets with low advanced glycation end products improves cardiometabolic parameters: meta-analysis of randomised controlled trials

Studies examining the effects of consumption of diets low in advanced glycation end products (AGEs) on cardiometabolic parameters are conflicting. Hence, we performed a meta-analysis to determine the effect of low AGE diets in reducing cardiometabolic risk factors. Seventeen randomised controlled trials comprising 560 participants were included. Meta-analyses using random effects models were used to analyse the data. Low AGE diets decreased insulin resistance (mean difference [MD] −1.3, 95% CI −2.3, −0.2), total cholesterol (MD −8.5 mg/dl, 95% CI −9.5, −7.4) and low-density lipoprotein (MD −2.4 mg/dl, 95% CI −3.4, −1.3). There were no changes in weight, fasting glucose, 2-h glucose and insulin, haemoglobin A1c, high-density lipoprotein or blood pressure. In a subgroup of patients with type 2 diabetes, a decrease in fasting insulin (MD −7 µU/ml, 95% CI −11.5, −2.5) was observed. Tumour necrosis factor α, vascular cell adhesion molecule-1, 8-isoprostane, leptin, circulating AGEs and receptor for AGEs were reduced after consumption of low AGE diets with increased adiponectin and sirtuin-1. Our findings suggest that diets low in AGEs may be an effective strategy for improving cardiometabolic profiles in individuals with and without type 2 diabetes.

(-)-Epicatechin-3-O-β-D-allopyranoside from Davallia formosana prevents diabetes and dyslipidemia in streptozotocin-induced diabetic mice

The objective of this study was to evaluate the effects and molecular mechanism of (-)-epicatechin-3-O-β-D-allopyranoside from Davallia formosana (BB) (also known as Gu-Sui-Bu) on type 1 diabetes mellitus and dyslipidemia in streptozotocin (STZ)-induced diabetic mice. This plant was demonstrated to display antioxidant activities and possess polyphenol contents. Diabetic mice were randomly divided into six groups and were given daily oral gavage doses of either BB (at three dosage levels), metformin (Metf) (at 0.3 g/kg body weight), fenofibrate (Feno) (at 0.25 g/kg body weight) or vehicle (distilled water) and a group of control (CON) mice were gavaged with vehicle over a period of 4 weeks. Treatment with BB led to reduced levels of blood glucose, HbA1C, triglycerides and leptin and to increased levels of insulin and adiponectin compared with the vehicle-treated STZ group. The diabetic islets showed retraction from their classic round-shaped as compared with the control islets. The BB-treated groups (at middle and high dosages) showed improvement in islets size and number of Langerhans islet cells. The membrane levels of skeletal muscular glucose transporter 4 (GLUT4) were significantly higher in BB-treated mice. This resulted in a net glucose lowering effect among BB-treated mice. Moreover, BB enhanced the expression of skeletal muscle phospho-AMPK in treated mice. BB-treated mice increased expression of fatty acid oxidation enzymes, including peroxisome proliferator-activated receptor α (PPARα) and mRNA levels of carnitine palmitoyl transferase Ia (CPT1a). These mice also expressed lower levels of lipogenic genes such as fatty acid synthase (FAS), as well as lower mRNA levels of sterol regulatory element binding protein 1c (SREBP1c) and liver adipocyte fatty acid binding protein 2 (aP2). This resulted in a reduction in plasma triglyceride levels. BB-treated mice also expressed lower levels of PPARγ and FAS protein. This led to reduced adipogenesis, fatty acid synthesis and lipid accumulation within adipose tissue, and consequently, to lower triglyceride levels in liver, blood, and adipose tissue. Moreover, BB treatment not only displayed the activation Akt in liver tissue and skeletal muscle, but also in C2C12 myotube to cause an increase in phosphorylation of Akt in the absence of insulin. These results demonstrated that BB act as an activator of AMPK and /or regulation of insulin pathway (Akt), and the antioxidant activity within the pancreas. Therefore, BB treatment ameliorated the diabetic and dyslipidemic state in STZ-induced diabetic mice.

High-Sensitivity Cardiac Troponin T (hs-cTnT) as a Predictor of Incident Diabetes in the Atherosclerosis Risk in Communities Study

OBJECTIVE

Many individuals with prediabetes have evidence of subclinical myocardial damage and are at an increased risk of cardiovascular disease (CVD). If subclinical myocardial damage is independently associated with incident diabetes, this may contribute to the understanding of the association between diabetes and CVD. This study was conducted to determine whether high-sensitivity cardiac troponin T (hs-cTnT) is associated with incident diabetes.

RESEARCH DESIGN AND METHODS

Using Kaplan-Meier curves and Cox models, we prospectively analyzed 8,153 participants without known diabetes or CVD. We used the Harrell C statistic to investigate whether hs-cTnT added incremental prognostic information for diabetes prediction.

RESULTS

During a median of 13 years of follow-up, there were 1,830 incident cases of diagnosed diabetes. After adjustment for demographics and traditional risk factors, participants with a baseline hs-cTnT of 9-13 ng/L or ≥14 ng/L had a significantly increased risk for diabetes compared to those with an hs-cTnT of ≤5 ng/L, with hazard ratios of 1.14 (95% CI 0.99-1.33) and 1.25 (95% CI 1.03-1.53), respectively (P = 0.018 for trend). Linear spline modeling that included adjustment for baseline fasting glucose suggested an increased risk of incident diabetes for participants with hs-cTnT levels >8 ng/L. Furthermore, the addition of hs-cTnT to fully adjusted models that included glucose significantly improved the prediction of incident diabetes from 0.7636 to 0.7644 (P = 0.023).

CONCLUSIONS

Participants with elevated hs-cTnT levels at baseline had an increased risk of incident diabetes, suggesting that the measurement of hs-cTnT may incorporate an underlying pathophysiologic overlap between diabetes and CVD not captured by other traditional risk factors. Measurement of hs-cTnT may be useful to identify individuals at an increased risk for incident diabetes and CVD in order to provide early and more intensive risk factor modification.

Nuclear factor E2-related factor 2 knockdown enhances glucose uptake and alters glucose metabolism in AML12 hepatocytes

Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor known to induce the expression of a variety of antioxidant and detoxification genes. Recently, increasing evidence has revealed roles for Nrf2 in glucose, lipid, and energy metabolism; however, the exact functions of Nrf2 in hepatocyte biology are largely unclear. In the current study, the transient knockdown of Nrf2 via siRNA transfection enhanced the glucose uptake of fasting AML12 hepatocytes to 325.3 ± 11.1% ( P < 0.05) of that of untransfected control cells. The impacts of Nrf2 knockdown (NK) on the antioxidant system, inflammatory response, and glucose metabolism were then examined in AML12 cells under both high-glucose (33 mmol/L) and low-glucose (4.5 mmol/L) conditions. NK lowered the gene and protein expression of the anti-oxidases heme oxygenase-1 and NAD(P)H: quinone oxidoreductase 1 and increased p-eukaryotic initiation factor-2α^S51, p-nuclear factor-κB p65^S276, and its downstream proinflammatory factors, including interleukin-1 beta, tumor necrosis factor-α, matrix metalloproteinase 2, and matrix metalloproteinase 9, at the protein level. NK also altered the protein expression of fibroblast growth factor 21, glucose transporter type 4, insulin-like growth factor 1, forkhead box protein O1, p-AKT^S473, and p-GSK3α/β^Y279/Y216, which are involved in glucose uptake, glycogenesis, and gluconeogenesis in AML12 cells. Our results provide a comprehensive understanding of the central role of Nrf2 in the regulation of glucose metabolism in AML12 hepatocytes, in addition to its classical roles in the regulation of redox signaling, endoplasmic reticulum stress and proinflammatory responses, and support the potential of Nrf2 as a therapeutic target for the prevention and treatment of obesity and other associated metabolic syndromes. Impact statement Increasing evidence supports the complexity of Nrf2 functions beyond the antioxidant and detoxification response. Previous in vivo studies employing either Nrf2-knockout or Nrf2-activated mice have achieved a similar endpoint: protection against an obese and insulin-resistant phenotype that includes impaired lipogenesis and gluconeogenesis in the liver. These apparently paradoxical observations led us to evaluate the impact of Nrf2 in liver cells in the absence of any influence from the systemic environment, including changes in the secretion of adipokines and proinflammatory cytokines by adipose tissues. In the present study, Nrf2 knockdown was sufficient to induce fundamental changes in the glucose metabolism of AML12 hepatocytes in addition to its classical cytoprotective functions. We also discuss similarities and differences between our in vitro study and previous in vivo studies, which may be helpful to dissect and better understand in vivo data that represents the culmination of both local and systemic alterations.

Skin autofluorescence (a marker for advanced glycation end products) and erectile dysfunction in diabetes

AIM

Although diabetes-related erectile dysfunction (ED) has many etiological factors, little is known about the putative pathophysiological role of advanced glycation end products (AGEs). Skin autofluorescence is a noninvasive marker of AGEs. Recent studies have evidenced a relationship between skin autofluorescence and several complications of diabetes. We hypothesized that AGEs (assessed by skin autofluorescence) are associated with ED in diabetes patients.

METHODS

Between March 2014 and April 2015, 42 patients with type 1 diabetes (T1D) and 44 patients with type 2 diabetes (T2D) were consecutively enrolled in a descriptive, cross-sectional study and compared to 54 healthy controls. ED was evaluated via the 5-item version of the International Index of Erectile Function (IIEF-5). Skin autofluorescence was measured on the volar aspect of the arm with an AGE-Reader.

RESULTS

Patients with diabetes had a mean±standard deviation age of 50±15 and a mean duration of diabetes of 16±12years. Skin autofluorescence was strongly and significantly correlated with the IIEF-5 score in the T1D subgroup (r=-0.52; P=0.004), the T2D subgroup (r=-0.32; P<0.03) and in the whole group of diabetic patients (r=-0.49; P<0.0001). In multivariate analyses that controlled for potentially confounding clinical and biochemical factors, only skin autofluorescence was still significantly correlated with the IIEF-5 score (P<0.0001). A receiver operating characteristic analysis revealed that a skin autofluorescence value ≥3.2AU determined severe ED with a sensitivity of 60% and a specificity of 87% in diabetic patients.

CONCLUSION

Skin autofluorescence is significantly associated with ED in diabetes, independently of classical confounding factors.

The impact of type 2 diabetes on bone metabolism

Diabetes complications and osteoporotic fractures are two of the most important causes of morbidity and mortality in older patients and share many features including genetic susceptibility, molecular mechanisms, and environmental factors. Type 2 diabetes mellitus (T2DM) compromises bone microarchitecture by inducing abnormal bone cell function and matrix structure, with increased osteoblast apoptosis, diminished osteoblast differentiation, and enhanced osteoclast-mediated bone resorption. The linkage between these two chronic diseases creates a possibility that certain antidiabetic therapies may affect bone quality. Both glycemic and bone homeostasis are under control of common regulatory factors. These factors include insulin, accumulation of advanced glycation end products, peroxisome proliferator-activated receptor gamma, gastrointestinal hormones (such as the glucose-dependent insulinotropic peptide and the glucagon-like peptides 1 and 2), and bone-derived hormone osteocalcin. This background allows individual pharmacological targets for antidiabetic therapies to affect the bone quality due to their indirect effects on bone cell differentiation and bone remodeling process. Moreover, it's important to consider the fragility fractures as another diabetes complication and discuss more deeply about the requirement for adequate screening and preventive measures. This review aims to briefly explore the impact of T2DM on bone metabolic and mechanical proprieties and fracture risk.

The Initial Months of Antiretroviral Therapy and Its Influence on AGEs, HMGB1, and sRAGE Levels in Asymptomatic HIV-Infected Individuals

The development of the typical comorbidities of aging which currently affects people living with HIV/AIDS (PLWHA) can be partially ascribed to the persistent immune activation and chronic inflammation characterizing these individuals. The aim of this study was to analyze the effect exerted by combined antiretroviral therapy (cART) administration on plasma levels of HMGB1 (high mobility group box protein-1), AGEs (advanced glycation end products), their soluble receptor sRAGE, cytokines, C-reactive protein (CRP), and some metabolic markers in asymptomatic PLWHA. Analyses were performed longitudinally in 30 PLWHA, before and about 6–12 months after cART initiation. We observed that lower levels of AGEs in post-cART group were accompanied by an increase of CRP and triglyceride levels already in the early months of therapy. Because of the current ever-earlier recommendations to start cART and its prolonged use, these and other markers should be investigated in order to monitor and postpone the appearance of non-AIDS comorbidities in PLWHA.

Skin autofluorescence predicts cardio-renal outcome in type 1 diabetes: a longitudinal study

Background

We aimed to analyze the relationships between skin autofluorescence (SAF) and incident macrovascular events and renal impairment after 4 years of follow-up in patients with type 1 diabetes (T1D).

Methods

Two hundred and forty-three patients (51.2 ± 16.7 years old) with T1D participated. SAF was measured by AGE-Reader-TM at inclusion. Macrovascular events (MVE), estimated glomerular filtration rate (eGFR) and urinary albumin excretion rate (AER) were recorded then and 4 years later. Multivariate logistic regression was used to analyze the relationships between SAF and incident MVE and renal profile 4 years later.

Results

Patients with incident MVE had a higher SAF (p = 0.003). SAF predicted incident MVE after adjustment for age, sex, body mass index, tobacco, diabetes duration, hypertension, HbA_1c, AER, eGFR (OR 4.84 [95 % CI 1.31–17.89], p = 0.018). However, this relation was no longer significant after adjustment for history of MVE. An inverse relation was found between SAF and incident eGFR (p = 0.0001). Patients with incident eGFR <60 ml/min/1.73 m² had a SAF higher than patients with normal eGFR. After adjustment for the previous criteria, SAF remained associated with the risk of impaired incident eGFR (OR 7.42 [95 % CI 1.59–34.65], p = 0.018). No relation was found between SAF and increased AER 4 years later.

Conclusions

SAF predicts MVE in patients with T1D, adjusted for cardiovascular risk factors but the most powerful predictive factor remains history of MVE. SAF also predicts eGFR impairment, adjusted for initial AER and renal function. SAF could be a useful non-invasive tool for estimating risk of cardiovascular or renal impairment in patients with T1D.

Dysfunctional protection against advanced glycation due to thiamine metabolism abnormalities in gestational diabetes

While the pathogenic role of dicarbonyl stress and accelerated formation of advanced glycation end products (AGEs) to glucose intolerance and to the development of diabetic complications is well established, little is known about these processes in gestational diabetes mellitus (GDM), a condition pathogenically quite similar to type 2 diabetes. The aims of the present study were (i) to determine plasma thiamine and erythrocyte thiamine diphosphate (TDP) and transketolase (TKT) activity in pregnant women with and without GDM, (ii) to assess relationships between thiamine metabolism parameters and selected clinical, biochemical and anthropometric characteristics and, finally, (iii) to analyse relationship between variability in the genes involved in the regulation of transmembrane thiamine transport (i.e. SLC19A2 and SLC19A3) and relevant parameters of thiamine metabolism. We found significantly lower plasma BMI adjusted thiamine in women with GDM (P = 0.002, Mann-Whitney) while levels of erythrocyte TDP (an active TKT cofactor) in mid-trimester were significantly higher in GDM compared to controls (P = 0.04, Mann-Whitney). However, mid-gestational TKT activity - reflecting pentose phosphate pathway activity - did not differ between the two groups (P > 0.05, Mann-Whitney). Furthermore, we ascertained significant associations of postpartum TKT activity with SNPs SLC19A2 rs6656822 and SLC19A3 rs7567984 (P = 0.03 and P = 0.007, resp., Kruskal-Wallis). Our findings of increased thiamine delivery to the cells without concomitant increase of TKT activity in women with GDM therefore indicate possible pathogenic role of thiamine mishandling in GDM. Further studies are needed to determine its contribution to maternal and/or neonatal morbidity.

Early Formation of Serum Advanced Glycation End-Products in Children with Type 1 Diabetes Mellitus: Relationship with Glycemic Control

OBJECTIVES

To quantify serum advanced glycation end-products (AGEs) at the onset of type 1 diabetes mellitus and to determine their potential usefulness as retrospective indicators of glycemic balance.

STUDY DESIGN

Carboxymethyllysine (CML) and pentosidine concentrations were determined by liquid chromatography-tandem mass spectrometry in 3 groups of children with type 1 diabetes mellitus: group (Gr) 1, subjects included at disease onset (n = 36); Gr2, subjects with diabetes of 5 years duration (n = 48); Gr3, subjects with diabetes of 10 years duration and in control subjects (n = 33). Hemoglobin A1c (HbA1c) values were recorded over the entire course of treatment for assessing long-term glycemic balance.

RESULTS

Serum AGE concentrations were increased in all groups of subjects with diabetes compared with control subjects, but were highest in Gr1 (for CML: 0.155, 0.306, 0.219, and 0.224 mmol/mol Lys in control, Gr1, Gr2, and Gr3 subjects, respectively; for pentosidine: 312, 492, 365, and 403 nmol/mol Lys, respectively). AGE concentrations were closely correlated with HbA1c values (r = 0.78 for CML; r = 0.49 for pentosidine). In Gr2 and Gr3, the overall glycemic balance estimated by average HbA1c values was positively correlated with CML and pentosidine concentrations, especially in the first year of follow-up.

CONCLUSION

Our results indicate that AGE concentrations are elevated in serum at the time of diabetes mellitus diagnosis, suggesting that the deleterious role of AGEs in the development of long-term complications should be taken into account even at the initial stages of the disease. Moreover, in some circumstances, AGEs could serve as surrogate markers of HbA1c for monitoring glycemic control.

Hyperglycemia-associated alterations in cellular signaling and dysregulated mitochondrial bioenergetics in human metabolic disorders

Purpose

The severity of untreated or refractory diabetes mellitus has been functionally linked to elevated concentrations of free plasma glucose, clinically defined as hyperglycemia. Operationally, the pathophysiological presentations of prolonged hyperglycemia may be categorized within insulin-dependent and insulin-independent, type 1 and type 2 diabetic phenotypes, respectively. Accordingly, major areas of empirical biomedical research have focused on the elucidation of underlying mechanisms driving key cellular signaling systems that are significantly altered in patients presenting with diabetes-associated chronic hyperglycemia.

Methods

Presently, we provide a translationally oriented review of key studies evaluating the aberrant effects of hyperglycemia on two major signaling pathways linked to debilitating cellular and systemic effects via targeted disruption of mitochondrial bioenergetics: (1) advanced glycation end-products (AGEs)/and their cognate receptor for advanced glycation end-products (RAGEs), and (2) the hexosamine biosynthetic pathway (HBP).

Results

In preclinical models, cultured vascular endothelial cells exposed to hyperglycemic glucose concentrations were observed to produce enhanced levels of reactive oxygen species (ROS) functionally linked to increased formation of AGEs and expression of their cognate RAGEs. Importantly, inhibitors of AGEs formation, mitochondrial complex II, or un-couplers of oxidative phosphorylation, were observed to significantly reduce the effects of hyperglycemia on ROS production and cellular damage, thereby establishing a critical linkage to multiple levels of mitochondrial functioning. Hyperglycemia-mediated enhancement of mitochondrial ROS/superoxide production in vascular endothelial cells has been functionally linked to the shunting of glucose into the HBP with resultant long-term activation of pro-inflammatory signaling processes. Additionally, exposure of cultured cells to hyperglycemic conditions resulted in enhanced HBP-mediated inhibition of protein subunits of mitochondrial respiratory complexes I, III, and IV, intimately associated with normative cellular bioenergetics and ATP production.

Conclusions

Convergent lines of evidence link chronic hyperglycemic conditions to aberrant expression of AGEs/RAGEs and HBP signaling pathways in relation to the pathophysiological formation of ROS and pro-inflammatory processes on the functional dysregulation of mitochondrial bioenergetics.

Glycated Albumin is Independently Associated With Arterial Stiffness in Non-Diabetic Chronic Kidney Disease Patients

Glycated albumin (GA) exhibits atherogenic effects and increased serum GA levels are associated with the development of cardiovascular complications in diabetic patients. GA production also increases with aging, oxidative stress, and renal dysfunction. We performed this study to further ascertain the association between GA and arterial stiffness in nondiabetic chronic kidney disease (CKD) patients. We enrolled 129 nondiabetic CKD patients. Arterial stiffness was measured by brachial-ankle pulse wave velocity (baPWV) using a volume plethysmographic instrument along with simultaneous measurements of GA. Insulin resistance was determined with the homeostatic model assessment. The estimated glomerular filtration rate was calculated using serum creatinine and cystatin C according to the CKD-EPI Creatinine-Cystatin C equation adjusted for age, sex, and race (eGFRcr-cys). Nondiabetic CKD patients with arterial stiffness (baPWV ≥1400 cm/s) showed higher GA levels than those without arterial stiffness (14.2 [8.7-20.2]% vs 13.0 [8.8-18.9]%, P = 0.004). In the subgroup analysis, the patients who had both a higher GA level and a lower eGFRcr-cys, showed the highest baPWV compared with patients with a higher GA or a lower GFR alone. By Spearman's correlation analysis, GA correlated significantly with baPWV (r = +0.291, P = 0.001) and fasting serum glucose level (r = +0.191, P = 0.030), whereas The homeostatic model assessment of insulin resistance did not show any significant correlation with baPWV. Systolic blood pressure (r = +0.401 P < 0.001), age (r = +0.574, P < 0.001), high-density lipoprotein (HDL)-cholesterol level (r = -0.317, P < 0.001), and eGFRcr-cys (r = -0.285, P = 0.002) had a significant correlation with baPWV. According to multivariable logistic regression analysis, higher GA and systolic blood pressure were the independent risk factors affecting arterial stiffness. Our results suggest that serum GA is a potential risk factor of arterial stiffness in nondiabetic CKD patients.

Acute effects of statin on reduction of angiopoietin-like 2 and glyceraldehyde-derived advanced glycation end-products levels in patients with acute myocardial infarction: a message from SAMIT (Statin for Acute Myocardial Infarction Trial)

Experimental ischemia-reperfusion models have shown that 3-hydroxy-3methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, statins, have cardioprotective effects. SAMIT (Statin Acute Myocardial Infarction Trial) is a multicenter prospective open randomized trial, designed to evaluate the effects of statin treatment from the earliest stage on cardioprotection in patients with acute myocardial infarction (AMI). Patients were randomly assigned to receive atorvastatin (initial dose of 40 mg at admission followed by the maintenance dose of 10 mg/day for 30 days) or not (control), and then immediately underwent percutaneous coronary intervention (PCI) for the culprit lesion. The primary endpoints were infarct size and left ventricular function. The secondary endpoints were major adverse cardiac and cerebrovascular events (MACCE) and various biomarkers. There were no significant differences in baseline characteristics between 2 groups of the statin treatment group and the control group. The left ventricular ejection fraction increased at 6 months after the onset of AMI, compared with the baseline level in the atorvastatin group (P < 0.05), while it did not change in the control group. Although there were no significant differences in the MACCE, the changes in the levels of angiopoietin-like protein 2 (ANGPTL2) (P < 0.05), and glyceraldehyde-derived advanced glycation end-products, (TAGE) (P < 0.01) were suppressed at 2 weeks in the atorvastatin group, compared with the control group. Statin therapy started early after the onset reduced the levels of ANGPTL2 and TAGE, and thus, might have cardioprotective effects in patients with AMI.

Bioactive ginger constituents alleviate protein glycation by trapping methylglyoxal

Considerable evidence suggests that long-term pathological diabetes is a result of the accumulation of tissue macromolecules that have been progressively modified by nonenzymatic glycation of protein. Methylglyoxal (MGO) is a highly reactive endogenous dicarbonyl metabolite derived from multiple sources such as glucose and lipids and is thought to contribute greatly to protein glycation and the formation of advanced glycation end products (AGEs). In this study, we demonstrated for the first time that both [6]-shogaol (6S) and [6]-gingerol (6G), the major active components in ginger, markedly trapped MGO in vitro and consequently formed mono-MGO adducts, 6S-MGO and 6G-MGO, which were purified from the respective chemical reaction and characterized as novel compounds by NMR experiments and LC-MS/MS approaches. We revealed that the α-carbon of the carbonyl group in the side chain of 6S or 6G is the major active site for trapping MGO. We also demonstrated that 6S and 6G could effectively inhibit the formation of MGO-induced AGEs via trapping MGO in a time-dependent manner in the human serum albumin (HSA)-MGO system. Mono-MGO adducts, 6S-MGO and 6G-MGO, were determined to be the major conjugates in 6S- and 6G-treated HSA-MGO assays, respectively, using LC-ESI-MS techniques. These findings showed the potential effects of 6S and 6G on the prevention of protein glycation, suggesting regular consumption of ginger root extract may attenuate the progression of MGO-associated diabetic complications in patients.

Advanced Glycation-Modified Human Serum Albumin Evokes Alterations in Membrane and Eryptosis in Erythrocytes

Increased burden of advanced glycation end-products (AGEs) in case of hyperglycemic conditions leads to the development of retinopathy, nephropathy, and cardiovascular and neurological disorders such as Alzheimer's disease. AGEs are considered as pro-oxidants, and their accumulation increases the oxidative stress. The prolonged exposure to these AGEs is the fundamental cause of chronic oxidative stress. Abnormal morphology of red blood cells (RBCs) and excessive eryptosis has been observed in diabetes, glomerulonephritis, dyslipidemia, and obesity, but yet the contribution of extracellular AGEs remains undefined. In this study, we investigated the effect of AGEs on erythrocytes to determine their impact on the occurrence of different pathological forms of these blood cells. Specifically, carboxymethyllysine (CML), carboxyethyllysine (CEL), and Arg-pyrimidine (Arg-P) which have been reported to be the most pre-dominant AGEs formed under in vivo conditions were used in this study. Results suggested the eryptotic properties of CML, CEL, and Arg-P for RBCs, which were evident from the highly damaged cell membrane and occurrence of abnormal morphologies. Methylglyoxal-modified albumin showed more severe effects, which can be attributed to the high reactivity and pro-oxidant nature of glycation end products. These findings suggest the possible role of AGE-modified albumin towards the morphological changes in erythrocyte's membrane associated with diabetic conditions.

Changes in Structural-Mechanical Properties and Degradability of Collagen during Aging-associated Modifications

During aging, changes occur in the collagen network that contribute to various pathological phenotypes in the skeletal, vascular, and pulmonary systems. The aim of this study was to investigate the consequences of age-related modifications on the mechanical stability and in vitro proteolytic degradation of type I collagen. Analyzing mouse tail and bovine bone collagen, we found that collagen at both fibril and fiber levels varies in rigidity and Young's modulus due to different physiological changes, which correlate with changes in cathepsin K (CatK)-mediated degradation. A decreased susceptibility to CatK-mediated hydrolysis of fibrillar collagen was observed following mineralization and advanced glycation end product-associated modification. However, aging of bone increased CatK-mediated osteoclastic resorption by ∼27%, and negligible resorption was observed when osteoclasts were cultured on mineral-deficient bone. We observed significant differences in the excavations generated by osteoclasts and C-terminal telopeptide release during bone resorption under distinct conditions. Our data indicate that modification of collagen compromises its biomechanical integrity and affects CatK-mediated degradation both in bone and tissue, thus contributing to our understanding of extracellular matrix aging.

Preterm birth and future risk of maternal cardiovascular disease - is the association independent of smoking during pregnancy?

BACKGROUND

While the association of preterm birth and the risk of maternal cardiovascular disease (CVD) has been well-documented, most studies were limited by the inability to account for smoking during pregnancy - an important risk factor for both preterm birth and CVD. This study aimed to determine whether the increased future risk of maternal cardiovascular disease (CVD) associated with preterm birth is independent of maternal smoking during pregnancy.

METHODS

A population-based record linkage study of 797,056 women who delivered a singleton infant between 1994 and 2011 in New South Wales, Australia was conducted. Birth records were linked to the mothers' subsequent hospitaliation or death from CVD. Preterm births were categorised as late (35-36 weeks), moderate (33-34 weeks), or extreme (≤32 weeks); and as spontaneous or indicated. Cox proportional hazard regression was used to estimate adjusted hazard ratios (AHR) [95 % CI].

RESULTS

During the study period, 59,563 women (7.5 %) had at least one preterm birth. After adjustment for CVD risk factors other than smoking, AHR [95 % CI] of CVD among women who ever had a preterm birth was 1.78 [1.61-1.96]. Associations were greater for extreme (AHR = 1.98 [1.63-2.42]) and moderate (AHR = 2.06 [1.69-2.51]) than late preterm birth (AHR = 1.63 [1.44-1.85]), for indicated (AHR = 2.04 [1.75-2.38]) than spontaneous preterm birth (AHR = 1.65 [1.47-1.86]), and for having ≥ two (AHR = 2.29[1.75-2.99]) than having one preterm birth (AHR = 1.73[1.57-1.92]). A further adjustment for maternal smoking attenuated, but did not eliminate, the associations. Smoking during pregnancy was also independently associated with maternal CVD risks, with associations being stronger for mothers who smoked during last pregnancy (AHR = 2.07 [1.93-2.23]) than mothers who smoked during a prior pregnancy (AHR = 1.64 [1.41-1.90]).

CONCLUSIONS

Associations of preterm birth and maternal CVD risk are independent of maternal smoking during pregnancy. This underscores the importance of smoking cessation in reducing CVD and suggests that a history of preterm delivery (especially if severe, indicated or recurrent) identifies women who could be targeted for CVD screening and preventative therapies.