Cellular receptors for advanced glycation end products. Implications for induction of oxidant stress and cellular dysfunction in the pathogenesis of vascular lesions

A Longitudinal Study of the Antioxidant Barrier and Oxidative Stress in Morbidly Obese Patients after Bariatric Surgery. Does the Metabolic Syndrome Affect the Redox Homeostasis of Obese People?

This is the first study to evaluate both the antioxidant barrier, glutathione metabolism, and oxidative damage to proteins and lipids in morbidly obese patients undergoing bariatric treatment. The study included 65 patients with class 3 obesity divided into two subgroups: morbidly obese patients without metabolic syndrome (OB) and obese patients with metabolic syndrome (OB + MS). Blood samples were collected before surgery as well as one, three, six, and twelve months after the bariatric treatment. Superoxide dismutase and reduced glutathione (GSH) were significantly decreased, whereas glutathione reductase and uric acid were enhanced in morbidly obese patients before bariatric surgery as compared to lean control. Moreover, in the OB group, we observed the increase of superoxide dismutase (SOD) and the decrease of uric acid (UA) after the bariatric treatment; however, these changes were not observed in the OB + MS group. The oxidative damage to proteins (advanced glycation end products, AGE; advanced oxidation protein products, AOPP) and lipids (8-isoprostanes, 8-isop; 4-hydroxynoneal) was higher in OB as well as OB + MS patients. We noticed that AGE and AOPP levels diminished after the bariatric treatment, whereas redox status (ratio of GSH to oxidized glutathione) was still reduced in the OB + MS group. Summarizing, morbid obesity is associated with disturbances in the antioxidant barrier and enhanced oxidative damage to proteins and lipids. Although bariatric surgery improves redox homeostasis in obese patients, those with metabolic syndrome show a continuous decrease in the antioxidant status. In patients undergoing bariatric treatment, antioxidant supplementation may be considered.

Relationships of diabetes and hyperglycaemia with intraocular pressure in a Japanese population: the JPHC-NEXT Eye Study

Although a meta-analysis previously suggested a positive relationship between diabetes and intraocular pressure (IOP), the interrelationships among diabetes, IOP, and other ocular biometric parameters remain unclear. The present study investigated the relationships of diabetes, haemoglobin A1c (HbA1c), and serum glucose with IOP and ocular hypertension (IOP > 21 mmHg) in non-glaucomatous Japanese adults living in Chikusei City. Diabetes was defined as a self-reported history of diabetes, the use of antidiabetic medication, or HbA1c levels ≥6.5%. Among 6,786 enrolled participants aged 40 years and above, 734 were classified as diabetic (10.8%). After adjusting for several confounders, the IOP values were significantly higher in participants with diabetes than in those without diabetes (14.4 ± 0.1 vs. 13.9 ± 0.1 mmHg, P < 0.001) and were also significantly increased in those with elevated HbA1c and serum glucose levels (both P < 0.001). Moreover, diabetes was significantly related to ocular hypertension (multivariable-adjusted odds ratio, 1.75; 95% confidence interval, 1.09–2.81; P < 0.05). The positive influence of diabetes with ocular hypertension was consistent even after adjustment for central corneal thickness. In conclusion, diabetes, elevated HbA1c, and increased serum glucose are significant contributing factors for elevated IOP.

The Effect of Advanced Glycation End-Products and Aminoguanidine on Tnfα Production by Rat Peritoneal Macrophages

Objective

To evaluate the effect of advanced glycation end-products (AGEs) and the inhibitor of their formation, aminoguanidine, on tumor necrosis factor-α (TNFα) production (as a functional marker) by rat peritoneal macrophages (PMΦ).

Design

Charles River rats underwent a daily intraperitoneal injection of peritoneal dialysis solution [(PDS), 4.25 g/dL dextrose; Dialine, Travenol, Ashdod, Israel] for a 2-month period (group E). Another group of rats was subjected to the same protocol with the addition of 25 mg/kg aminoguanidine (group A). Three control groups were utilized: ( 1 ) rats that were injected daily with aminoguanidine only (group AO), ( 2 ) rats that were injected with Dulbecco's phosphate-buffered saline (group D), and ( 3 ) rats in which no intervention was carried out (group C). After 2 months, PMΦ were isolated from rat peritoneal effluent and their TNFα production measured by ELISA in cell-free culture supernatants, in both the basal state and after 24-hour stimulation with lipopolysaccharide (LPS). The concentrations of AGEs in peritoneal effluent were assayed and correlated to TNFα levels. PMΦ obtained from normal rats were then incubated for 24 hours with ( 1 ) the peritoneal effluent of each of the above respective groups, with or without LPS; ( 2 ) increasing concentrations of AGEs (0 - 250 μg/mL); and ( 3 ) increasing concentrations of aminoguanidine (0 - 7.5 mg/mL), and TNFα secretion again determined.

Results

After 2 months of daily intraperitoneal injection of PDS, in the basal state, TNFα production was significantly higher in PMΦ isolated from the peritoneal effluent groups (groups E, A, and AO) compared to controls (group C). Following LPS stimulation, a further increase in TNFα secretion was seen, with a significantly greater response in group AO versus groups E, A, and D. Effluent AGEs were markedly elevated only in group E. No correlation was found between TNFα secretion by these PMΦ and the concentration of AGEs. On incubation with the respective peritoneal effluents (groups E, A, and AO), in both the basal and stimulated state, TNFα production by PMΦ from normal rats was significantly enhanced compared to group C. Incubation with increasing concentrations of AGEs or aminoguanidine resulted in an increase of TNFα secretion by these PMΦ.

Conclusions

Following intermittent intraperitoneal administration of glucose-based PDS, rat PMΦ are chronically activated, as evidenced by increased basal TNFα secretion. The peritoneal effluent of such treated animals is capable of stimulating TNFα production by normal rat PMΦ. These data suggest that glucose-based PDS acts as a primer of PMΦ, which retain their ability to further stimulation by LPS. Although, in vitro, AGEs promote TNFα secretion by normal rat PMΦ, in vivo, their influence is probably modulated by other factors. Aminoguanidine has a specific inducing effect on rat PMΦ, independent of glucose-based PDS.

The Potential Cardiovascular Benefits of Low-Glucose Degradation Product, Biocompatible Peritoneal Dialysis Fluids: A Review of the Literature

Cardiovascular mortality in the end-stage renal disease (ESRD) population remains the leading cause of death. Targeting traditional cardiovascular risk factors has proven unsuccessful in this patient population, and therefore attention has turned to risk factors related to chronic kidney disease (CKD). The toxicity of high-glucose peritoneal dialysis (PD) solutions has been well documented. The breakdown of glucose into glucose degradation products (GDP) and advanced glycation end-products (AGE) has the ability to alter cell viability and cause premature apoptosis and is strongly correlated with interstitial fibrosis and microvascular sclerosis. Biocompatible solutions have been introduced to combat the hostile milieu to which PD patients are exposed.

Given the considerable cardiovascular burden for PD patients, little is known about the cardiovascular impact the new biocompatible solutions may have. This review analyzes the existing literature regarding the mechanisms through which low-GDP solutions may modulate cardiovascular risk. Interventions using low-GDP solutions have provided encouraging changes in structural cardiovascular measures such as left ventricular mass (LVM), although metabolic changes from reduced GDP and AGE exposure yield inconclusive results on vascular remodelling. It is thought that the local effects of reduced glucose exposure may improve membrane integrity and therefore fluid status. Further research in the form of a robust randomized controlled trial should be carried out to assess the true extent of the cardiovascular benefits these biocompatible solutions may hold.

Endothelial Dysfunction in Diabetic Retinopathy

Diabetic retinopathy (DR) is a diabetic complication which affects retinal function and results in severe loss of vision and relevant retinal diseases. Retinal vascular dysfunction caused by multifactors, such as advanced glycosylation end products and receptors, pro-inflammatory cytokines and chemokines, proliferator-activated receptor-γ disruption, growth factors, oxidative stress, and microRNA. These factors promote retinal endothelial dysfunction, which results in the development of DR. In this review, we summarize the contributors in the pathophysiology of DR for a better understanding of the molecular and cellular mechanism in the development of DR with a special emphasis on retinal endothelial dysfunction.

Crossing the blood-brain-barrier with nanoligand drug carriers self-assembled from a phage display peptide

The filamentous bacteriophage fd bind a cell target with exquisite specificity through its few copies of display peptides, whereas nanoparticles functionalized with hundreds to thousands of synthetically generated phage display peptides exhibit variable and often-weak target binding. We hypothesise that some phage peptides in a hierarchical structure rather than in monomeric form recognise and bind their target. Here we show hierarchial forms of a brain-specific phage-derived peptide (herein as NanoLigand Carriers, NLCs) target cerebral endothelial cells through transferrin receptor and the receptor for advanced glycation-end products, cross the blood-brain-barrier and reach neurons and microglial cells. Through intravenous delivery of NLC-β-secretase 1 (BACE1) siRNA complexes we show effective BACE1 down-regulation in the brain without toxicity and inflammation. Therefore, NLCs act as safe multifunctional nanocarriers, overcome efficacy and specificity limitations in active targeting with nanoparticles bearing phage display peptides or cell-penetrating peptides and expand the receptor repertoire of the display peptide.

Bacteriophages can bind targets with only a few copies of a display peptide while most nanoparticles with thousands achieve poor binding. Here the authors form hierarchical arrangements of phage peptides to delivery siRNA across the blood brain barrier.

Circulating Advanced Glycation Endproducts and Long-Term Risk of Cardiovascular Mortality in Kidney Transplant Recipients

BACKGROUND AND OBJECTIVES

In kidney transplant recipients, elevated circulating advanced glycation endproducts (AGEs) are the result of increased formation and decreased kidney clearance. AGEs trigger several intracellular mechanisms that ultimately yield excess cardiovascular disease. We hypothesized that, in stable kidney transplant recipients, circulating AGEs are associated with long-term risk of cardiovascular mortality, and that such a relationship is mediated by inflammatory, oxidative stress, and endothelial dysfunction biomarkers.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Prospective cohort study of stable kidney transplant recipients recruited between 2001 and 2003 in a university setting. We performed multivariable-adjusted Cox regression analyses to assess the association of AGEs (i.e., N^ε -[Carboxymethyl]lysine (CML) and N^ε -[Carboxyethyl]lysine (CEL), measured by tandem mass spectrometry) with cardiovascular mortality. Mediation analyses were performed according to Preacher and Hayes's procedure.

RESULTS

We included 555 kidney transplant recipients (age 51±12 years, 56% men). During a median follow-up of 6.9 years, 122 kidney transplant recipients died (52% deaths were due to cardiovascular causes). CML and CEL concentrations were directly associated with cardiovascular mortality (respectively, hazard ratio, 1.55; 95% confidence interval, 1.24 to 1.95; P<0.001; and hazard ratio, 1.53; 95% confidence interval 1.18 to 1.98; P=0.002), independent of age, diabetes, smoking status, body mass index, eGFR and proteinuria. Further adjustments, including cardiovascular history, did not materially change these findings. In mediation analyses, free thiol groups and soluble vascular cell adhesion molecule-1 consistently explained approximately 35% of the association of CML and CEL with cardiovascular mortality.

CONCLUSIONS

In stable kidney transplant recipients, circulating levels of AGEs are independently associated with long-term risk of cardiovascular mortality.

PODCAST

This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2019_09_17_CJN00540119.mp3.

Associations between Urinary Advanced Glycation End Products and Cardiometabolic Parameters in Metabolically Healthy Obese Women

Advanced glycation end products (AGEs) have been implicated in the pathophysiology of type 2 diabetes and cardiovascular disease. We aimed to determine the associations of urinary carboxymethyl-lysine (CML) and methylglyoxal-hydroimidazolone (MG-H1) levels with cardiometabolic parameters in metabolically healthy obese women. Anthropometric, glycemic, cardiovascular, and urinary AGE parameters were measured in 58 metabolically healthy obese women (age: 39.98 ± 8.72 years; body mass index (BMI): 32.29 ± 4.05 kg/m²). Urinary CML levels were positively associated with BMI (r = 0.29, p = 0.02). After adjustment for age and BMI, there was a trend for positive associations between urinary CML levels and fasting (p = 0.06) and 2 h insulin (p = 0.05) levels, and insulin resistance measured by homeostatic model assessment (HOMA-IR) (p = 0.06). Urinary MG-H1 levels were positively associated with systolic and diastolic blood pressure, pulse pressure, mean arterial pressure, and total and low-density lipoprotein cholesterol after adjustment for age, BMI, and HOMA-IR (all p ˂ 0.05). There were no associations between urinary CML levels and cardiovascular parameters, and between urinary MG-H1 levels and glycemic measurements. Our data support a role of urinary AGEs in the pathophysiology of insulin resistance and cardiovascular disease; however, future studies are highly warranted.

Inhibition of miR-25 aggravates diabetic peripheral neuropathy

The hyperglycemia-induced enhanced oxidative stress is a key factor of diabetic peripheral neuropathy implicated in the pathogenesis of diabetic neuropathy, and microRNA may be involved, playing promotion or protection roles. In this study, we aimed to investigate the function of miR-25 during the development of oxidative/nitrative stress and in subsequent neurological problems. We detected the oxidative stress effects and expression of miR-25 on sciatic nerves from db/db diabetic model mice and analyzed the expression of related genes by qPCR and Western blotting. Interestingly, we observed increased reactive oxygen species (ROS) and Nox4 expression in db/db mice accompanied with reduced miR-25. MiR-25 inhibitor treatment increased nicotinamide adenine dinucleotide phosphate activity in Schwann cells, whereas miR-25 precursor overexpression led to opposite results. MiR-25 precursor reduced the activation of protein kinase C and decreased Nox4 expression at both mRNA and protein levels. Advanced glycation endproducts (AGEs) and the receptor for advanced glycation endproducts (RAGE) were increased in the serum and in the peripheral nerves obtained from diabetic mice, and miR-25 inhibitor treatment in Schwann cells from wt mice led to the same effect. However, miR-25 precursor transfection reduced AGEs and RAGE, and further reduced inflammatory factors that contribute to the pathological process of peripheral nerves. These findings, for the first time, indicate that miR-25 acts as a protection factor in diabetic neuropathy by downregulating AGE-RAGE and reducing nicotinamide adenine dinucleotide phosphate oxidase. miR-25 reduced protein kinase C-α phosphorylation to produce less reactive oxygen species in diabetic peripheral nerves, and therefore it played an important role in the regulation of oxidative/nitrative stress and in consequent neurological dysfunction.

Divergent Changes in Plasma AGEs and sRAGE Isoforms Following an Overnight Fast in T1DM

Advanced glycation end products (AGEs) promote the development of diabetic complications through activation of their receptor (RAGE). Isoforms of soluble RAGE (sRAGE) sequester AGEs and protect against RAGE-mediated diabetic complications. We investigated the effect of an overnight fast on circulating metabolic substrates, hormones, AGEs, and sRAGE isoforms in 26 individuals with type 1 diabetes (T1DM). Blood was collected from 26 young (18–30 years) T1DM patients on insulin pumps before and after an overnight fast. Circulating AGEs were measured via LC-MS/MS and sRAGE isoforms were analyzed via ELISA. Glucose, insulin, glucagon, and eGFR_cystatin-c decreased while cortisol increased following the overnight fast (p < 0.05). AGEs (CML, CEL, 3DG-H, MG-H1, and G-H1) decreased (21–58%, p < 0.0001) while total sRAGE, cleaved RAGE (cRAGE), and endogenous secretory RAGE (esRAGE) increased (22–24%, p < 0.0001) following the overnight fast. The changes in sRAGE isoforms were inversely related to MG-H1 (rho = −0.493 to −0.589, p < 0.05) and the change in esRAGE was inversely related to the change in G-H1 (rho = −0.474, p < 0.05). Multiple regression analyses revealed a 1 pg/mL increase in total sRAGE, cRAGE, or esRAGE independently predicted a 0.42–0.52 nmol/L decrease in MG-H1. Short-term energy restriction via an overnight fast resulted in increased sRAGE isoforms and may be protective against AGE accumulation.

Exercise and Arterial Modulation in Children: The EXAMIN YOUTH Study

Background: Cardiovascular disease (CVD) remains to be one of the most frequent causes of death worldwide. Cardiovascular (CV) risk factors such as hypertension and obesity often manifest in childhood. The study examines the associations of blood pressure, body mass index and physical activity with cardiopulmonary, metabolic, and psychosocial health of children in a systems physiology approach. Methods/Design: This cross-sectional study will be performed in a cohort of 6 to 8 year old school children (n = 1000). As a measure of vascular health, retinal microvascular diameters and large artery pulse wave velocity will be examined. Anthropometric parameters, such as weight, height, body mass index, and blood pressure will be assessed according to standardized protocols for children. Physical fitness and activity will be measured by a 20 m shuttle run, a 20 m sprint and a proxy-reported questionnaire on lifestyle behavior. Spirometry, assessment of heart rate variability and skin advanced glycation end products as well as a flanker test will be performed to determine systemic end organ alterations. Discussion: The study offers a unique integrative primary prevention concept that aims to set the grounds for a healthy and active lifestyle approach during childhood. It will help optimize CV risk stratification to identify children at risk of disease progression later in life. The study will demonstrate the importance of specific CV screening programs in children to reduce the growing burden of CV disease in adulthood. Prospective follow-up studies will have to prove the efficacy of primary prevention programs in children to achieve healthier aging as a long-term goal.

Positive Association Between Plasma Levels of Advanced Glycation and Precursor of Lipoxidation end Products with Gastrointestinal Problems in Children with Autism

BACKGROUND

Increased oxidative stress has been reported in autistic patients besides, evidence linking oxidative stress to enhancement of advanced glycation and lipoxidation end products (AGEs and ALEs) and their precursors.

OBJECTIVE

This study aimed to compare the plasma levels of the AGEs and precursors of ALEs in autistic and healthy children and to evaluate their relationship with autism comorbidities.

METHODS

In this descriptive study, 54 children, 36 autistic and 18 healthy participated. Plasma levels of AGEs and precursors of ALEs were measured by ELISA method. Severity of autism and Gastrointestinal (GI) disorders were measured by GARSII questionnaire and QPGS-ROME III questionnaire, respectively.

RESULTS

Plasma levels of AGEs and precursors of ALEs in autistic children were comparable with healthy children. Plasma levels of AGEs and precursor of ALEs were correlated with physical activity and GI disorders in autistic children. A strong association was also found between AGEs and precursors of ALEs.

CONCLUSION

The results indicate that AGEs and ALEs have a strong correlation together but the AGEs and precursor of ALEs in autistic children are not different from healthy children.

Hsa-miRNA-29a protects against high glucose-induced damage in human umbilical vein endothelial cells

Sustained exposure to high glucose (HG) results in dysfunction of vascular endothelial cells. Hence, diabetic patients often suffer from secondary vascular damages, such as vascular sclerosis and thrombogenesis, which may eventually cause cardiovascular problems. Thus, elucidating how HG results in vascular endothelial cell damage and finding an approach for prevention are important to prevent and treat vascular damages in diabetic patients. In the current study, we first showed that 72-hour exposure to HG-decreased hsa-miRNA-29a and increased the expression of Bcl-2 associated X protein (Bax), which subsequently inhibited Bcl-2 and promoted the expression of apoptotic protease activating factor-1 and activation of caspase-3, thus directly triggering the mitochondrial apoptotic pathway in human umbilical vein endothelial cells (HUVECs). Study of the underlying mechanism showed that hsa-miRNA-29a/Bax plays an essential role in the decreased proliferation and increased apoptosis of HUVECs induced by HG, and overexpression of hsa-miRNA-29a effectively inhibits HG-induced apoptosis and restores the proliferation and tube formation of HUVECs exposed to HG by inhibiting its target gene Bax. In short, our study demonstrates that hsa-miRNA-29a is a promising target for the prevention and treatment of vascular injury in diabetic patients.

The role of advanced glycation end-products in the development of coronary artery disease in patients with and without diabetes mellitus: a review

Background

Traditional risk factors are insufficient to explain all cases of coronary artery disease (CAD) in patients with diabetes mellitus (DM). Advanced glycation end-products (AGEs) and their receptors may play important roles in the development and progression of CAD.

Body

Hyperglycemia is the hallmark feature of DM. An increase in the incidence of both micro-and macrovascular complications of diabetes has been observed with increased duration of hyperglycemia. This association persists even after glycemic control has been achieved, suggesting an innate mechanism of “metabolic memory.” AGEs are glycated proteins that may serve as mediators of metabolic memory due to their increased production in the setting of hyperglycemia and generally slow turnover. Elevated AGE levels can lead to abnormal cross linking of extracellular and intracellular proteins disrupting their normal structure and function. Furthermore, activation of AGE receptors can induce complex signaling pathways leading to increased inflammation, oxidative stress, enhanced calcium deposition, and increased vascular smooth muscle apoptosis, contributing to the development of atherosclerosis. Through these mechanisms, AGEs may be important mediators of the development of CAD. However, clinical studies regarding the role of AGEs and their receptors in advancing CAD are limited, with contradictory results.

Conclusion

AGEs and their receptors may be useful biomarkers for the presence and severity of CAD. Further studies are needed to evaluate the utility of circulating and tissue AGE levels in identifying asymptomatic patients at risk for CAD or to identify patients who may benefit from invasive intervention.

Endogenous secretory RAGE increases with improvements in body composition and is associated with markers of adipocyte health

BACKGROUND AND AIMS

The receptor for advanced glycation end products (RAGE) is implicated in obesogenesis. Conversely, soluble RAGE (sRAGE) competitively inhibits RAGE. Our aim was to determine the effects of weight-loss via alternate day fasting (ADF) on sRAGE isoforms and evaluate potential relationships with body composition.

METHODS AND RESULTS

42 obese participants were randomized to control (CON) or ADF. For 24 weeks, the ADF group consumed 25% or 125% of their caloric requirements on alternating days while the CON group did not change their diet. Body fat was measured via DXA, visceral fat (VAT) via MRI and subcutaneous fat (SAT) was derived by subtracting VAT from total fat. sRAGE isoforms were measured via ELISAs. After 24 weeks, ADF -6.8 (-9.5, -3.5)kg (Median, IQR) lost more weight than CON -0.3 (-1.9, 1.0)kg (p < 0.05). The change in endogenous secretory RAGE (esRAGE) was different between ADF 15 (-30, 78)pg/mL and CON -21 (-72, 16)pg/mL after 24 weeks (p < 0.05). To examine the effect of changes in body composition, the cohort was stratified by median weight-, fat-, SAT-, and VAT-loss. The changes in all sRAGE isoforms were different between those above and below median weight-loss (p < 0.05) with sRAGE isoforms tending to decrease in individuals below the median. Changes in total sRAGE and esRAGE were different between individuals above compared to below median fat- and SAT-loss (p < 0.05). Those above median fat-loss increased esRAGE by 29 (-5, 66)pg/mL (p < 0.05).

CONCLUSION

Improvements in body composition are related to increased sRAGE isoforms, implicating sRAGE as a potential target for the treatment of obesity.

CLINICAL TRIAL REGISTRATION

NCT00960505.

Immunomodulation by Processed Animal Feed: The Role of Maillard Reaction Products and Advanced Glycation End-Products (AGEs)

The immune system provides host protection to infection with pathogenic organisms, while at the same time providing tolerance upon exposure to harmless antigens. Thus, an impaired immune function is associated with increased susceptibility to infections with increased disease severity and thereby necessitating the therapeutic use of antibiotics. Livestock performance and feed efficiency, in addition to their health status, are dependent on the microbial load of their gut, the barrier function of the intestinal epithelium and the activity of the mucosal immune system, all of which can be modulated by dietary components. The majority of feeds that are consumed in pets and livestock have been processed. Processing promotes a non-enzymatic reaction between proteins and sugars called Maillard reaction (MR). Maillard reaction products (MRPs) and advanced Maillard reaction products (AGEs) determine taste, smell, and color of many food products therefore the MR is highly relevant for the feed industry. MRPs interact with different types of immune receptors, including the receptor for advanced glycation end products (RAGE) and immunomodulatory potential of feed proteins can be modified by Maillard reaction. This MR has become an important concern since MRPs/AGEs have been shown to contribute to increasing prevalence of diet-related chronic inflammatory states in the gut with negative health consequences and performance. The immunomodulatory effects of dietary MRPs and AGEs in livestock and pet animals are far less well-described, but widely considered to be similar to the relevant concepts and mechanisms obtained in the human field. This review will highlight immunological mechanisms underlying initiation of the innate and adaptive immune responses by MRPs/AGEs present in animal feeds, which are currently not completely understood. Bridging this knowledge gap, and taking advantage of progress in the human field, will significantly improve nutritional quality of feed and increase the prevention of diet-mediated inflammation in animals.

Chelation therapy to prevent diabetes-associated cardiovascular events

PURPOSE OF REVIEW

For over 60 years, chelation therapy with disodium ethylene diamine tetraacetic acid (EDTA, edetate) had been used for the treatment of cardiovascular disease (CVD) despite lack of scientific evidence for efficacy and safety. The Trial to Assess Chelation Therapy (TACT) was developed and received funding from the National Institutes of Health (NIH) to ascertain the safety and efficacy of chelation therapy in patients with CVD.

RECENT FINDINGS

This pivotal trial demonstrated an improvement in outcomes in postmyocardial infarction (MI) patients. Interestingly, it also showed a particularly large reduction in CVD events and all-cause mortality in the prespecified subgroup of patients with diabetes. The TACT results may support the concept of metal chelation to reduce metal-catalyzed oxidation reactions that promote the formation of advanced glycation end products, a precursor of diabetic atherosclerosis.

SUMMARY

In this review, we summarize the epidemiological and basic evidence linking toxic metal accumulation and diabetes-related CVD, supported by the salutary effects of chelation in TACT. If the ongoing NIH-funded TACT2, in diabetic post-MI patients, proves positive, this unique therapy will enter the armamentarium of endocrinologists and cardiologists seeking to reduce the atherosclerotic risk of their diabetic patients.

Glutathione: Antioxidant Properties Dedicated to Nanotechnologies

Which scientist has never heard of glutathione (GSH)? This well-known low-molecular-weight tripeptide is perhaps the most famous natural antioxidant. However, the interest in GSH should not be restricted to its redox properties. This multidisciplinary review aims to bring out some lesser-known aspects of GSH, for example, as an emerging tool in nanotechnologies to achieve targeted drug delivery. After recalling the biochemistry of GSH, including its metabolism pathways and redox properties, its involvement in cellular redox homeostasis and signaling is described. Analytical methods for the dosage and localization of GSH or glutathiolated proteins are also covered. Finally, the various therapeutic strategies to replenish GSH stocks are discussed, in parallel with its use as an addressing molecule in drug delivery.

Revisiting amino acids and peptides as anti-glycation agents

The importance of controlling or preventing protein glycation cannot be overstated and is of prime importance in the treatment of diabetes and associated complications including Alzheimer's disease, cataracts, atherosclerosis, kidney aliments among others. In this respect, simple molecules such as amino acids and peptides hold much promise both in terms of ease and scale-up of synthesis as well as in relation to negligible/low associated toxicity. In view of this, a comprehensive account of literature reports is presented, that documents the anti-glycation activity of natural and non-natural amino acids and peptides. This review also discusses the chemical reactions involved in glycation and the formation of advanced glycation end-products (AGEs) and possible/probable intervention sites and mechanism of action of the reported amino acids/peptides. This aspect of amino acids/peptides adds to their growing importance in medicinal and therapeutic applications.

Extracellular Matrix and Ageing

The extracellular matrix (ECM) provides the environment for many cells types within the body and, in addition to the well recognised role as a structural support, influences many important cell process within the body. As a result, age-related changes to the proteins of the ECM have far reaching consequences with the potential to disrupt many different aspects of homeostasis and healthy function. The proteins collagen and elastin are the most abundant in the ECM and their ability to function as a structural support and provide mechanical stability results from the formation of supra-molecular structures. Collagen and elastin have a long half-life, as required by their structural role, which leaves them vulnerable to a range of post-translational modifications. In this chapter the role of the ECM is discussed and the component proteins introduced. Major age-related modifications including glycation, carbamylation and fragmentation and the impact these have on ECM function are reviewed.

Diabetic Microvascular Disease: An Endocrine Society Scientific Statement

Both type 1 and type 2 diabetes adversely affect the microvasculature in multiple organs. Our understanding of the genesis of this injury and of potential interventions to prevent, limit, or reverse injury/dysfunction is continuously evolving. This statement reviews biochemical/cellular pathways involved in facilitating and abrogating microvascular injury. The statement summarizes the types of injury/dysfunction that occur in the three classical diabetes microvascular target tissues, the eye, the kidney, and the peripheral nervous system; the statement also reviews information on the effects of diabetes and insulin resistance on the microvasculature of skin, brain, adipose tissue, and cardiac and skeletal muscle. Despite extensive and intensive research, it is disappointing that microvascular complications of diabetes continue to compromise the quantity and quality of life for patients with diabetes. Hopefully, by understanding and building on current research findings, we will discover new approaches for prevention and treatment that will be effective for future generations.

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.

Diabetic retinopathy: Breaking the barrier

Diabetic retinopathy (DR) remains a major complication of diabetes and a leading cause of blindness among adults worldwide. DR is a progressive disease affecting both type I and type II diabetic patients at any stage of the disease, and targets the retinal microvasculature. DR results from multiple biochemical, molecular and pathophysiological changes to the retinal vasculature, which affect both microcirculatory functions and ultimately photoreceptor function. Several neural, endothelial, and support cell (e.g., pericyte) mechanisms are altered in a pathological fashion in the hyperglycemic environment during diabetes that can disturb important cell surface components in the vasculature producing the features of progressive DR pathophysiology. These include loss of the glycocalyx, blood-retinal barrier dysfunction, increased expression of inflammatory cell markers and adhesion of blood leukocytes and platelets. Included in this review is a discussion of modifications that occur at or near the surface of the retinal vascular endothelial cells, and the consequences of these alterations on the integrity of the retina.

Anticataractogenesis and Antiretinopathy Effects of the Novel Protective Agent Containing the Combined Extract of Mango and Vietnamese Coriander in STZ-Diabetic Rats

The novel protectant against diabetic cataract and diabetic retinopathy is currently required due to the increased prevalence and therapeutic limitation. Based on the advantage of polyphenol on diabetic eye complications, we hypothesized that the combined extract of mango seed Vietnamese coriander (MPO), a polyphenol-rich substance, should possess anticataractogenesis and antiretinopathy in streptozotocin- (STZ-) diabetic rats. MPO at doses of 2, 10, and 50 mg/kg·BW were orally given to STZ-diabetic rats for 10 weeks. Lens opacity was evaluated every week throughout a study period whereas the evaluation of cataract severity and histological changes of both rat lens epithelium and retina together with the biochemical assays of oxidative stress status, aldose reductase, p38MAPK, ERK1/2, and VEGF were performed at the end of experiment. Our data showed that MPO improved cataract and retinopathy in STZ-diabetic rats. The improved oxidative stress status and the decreased p38MAPK, ERK1/2, and VEGF were also observed. Therefore, anticataractogenesis and antiretinopathy of MPO might occur partly via the decreased oxidative stress status and the suppression of aldose reductase, p38MAPK, ERK1/2, and VEGF. This study points out that MPO is the potential candidate protectant against diabetic cataract and diabetic retinopathy. However, the exploration for possible active ingredient (S) still requires further researches.

Hesperidin reverses perivascular adipose-mediated aortic stiffness with aging

We tested the hypothesis that hesperidin would reverse age-related aortic stiffness, perivascular adipose (PVAT) mediated-arterial stiffening and PVAT advanced glycation end-products (AGE) accumulation. Aortic pulse wave velocity (aPWV) and intrinsic mechanical stiffness, two measures of arterial stiffness, were assessed in C57BL/6 mice that were young (6months), old (27-29months), or old treated with hesperidin for 4weeks. Old compared with young mice had increased aPWV (444±10 vs. 358±8cm/s, P<0.05) and mechanical stiffness (6506±369 vs. 3664±414kPa, P<0.05). In old mice hesperidin reduced both aPWV (331±38cm/s) and mechanical stiffness (4445±667kPa) to levels not different from young. Aortic segments from old animals cultured with (+) PVAT had greater mechanical stiffness compared to young (+) PVAT (6454±323 vs. 3575±440kPa, P<0.05) that was ameliorated in arteries from old hesperidin treated cultured (+) PVAT (2639±258kPa). Hesperidin also reversed the aging-related PVAT AGE accumulation (all, P<0.05). A 4-week treatment with the AGE inhibitor aminoguanidine reversed both the age-related increase in aPWV (390±7cm/s) and mechanical stiffness (3396±1072kPa), as well as mechanical stiffness in arteries cultured (+) PVAT (3292±716kPa) (all, P<0.05) to values not different from young. In conclusion, hesperidin ameliorates the age-related increase in aortic stiffness and the PVAT-mediated effects on arterial stiffening. Hesperidin also reversed PVAT AGE accumulation, where PVAT AGE were shown to promote aortic stiffness with aging.

Advanced glycation end products and strontium ranelate promote osteogenic differentiation of vascular smooth muscle cells in vitro: Preventive role of vitamin D

Advanced glycation end products (AGE) have been demonstrated to induce the osteogenic trans-differentiation of vascular smooth muscle cells (VSMC). Strontium ranelate (SR) is an anti-osteoporotic agent that has both anti-catabolic and anabolic actions on bone tissue. However, in the last years SR has been associated with an increase of cardiovascular risk. We hypothesize that SR can increase the osteoblastic trans-differentiation of VSMC and the induction of extracellular calcifications, an effect that could be potentiated in the presence of AGE and inhibited by simultaneous administration of vitamin D. The present results of our in vitro experiments demonstrate that AGE and SR alone or in combination, stimulate L-type calcium channels, causing an increase in reactive oxygen species and activation of both ERK and NFkB, with the final effect of promoting the osteogenic shift of VSMC. Importantly, these in vitro effects of AGE and/or SR can be prevented by co-incubation with vitamin D.

Serum soluble receptor of advanced glycation end products and risk of metabolic syndrome in Egyptian obese women

Obesity is one of the diagnostic criteria of metabolic syndrome (MS). It is correlated with insulin resistance (IR) and high vascular risk as well. Advanced glycation end products (AGEs) and their receptor (RAGE) play an important role in abnormal metabolic components in obese women. This study aimed to explore the serum levels of sRAGE in Egyptian obese women and compare with healthy non-obese controls and investigate the relationship between serum sRAGE, metabolic parameters, and obesity complications. The soluble form of receptor for advanced glycation end products (sRAGE), anthropometry, metabolic and biochemical biomarkers were measured in 100 obese women and 100 age-matched healthy control non-obese women. The homeostasis model assessment estimate of insulin resistance (HOMA-IR) has been determined from serum insulin and glucose values. Serum sRAGE levels were significantly lower in obese cases than controls and inversely correlated with obesity and metabolic parameters. Results of univariate and multivariate analyses for determinants of serum sRAGE levels in obese cases showed that parameters statistically and significantly related were body mass index (BMI), waist circumference (WC), LDL-C, TG, BP, HOMA-IR, ALT and AST. sRAGE is a novel biomarker for metabolic dysfunction in Egyptian obese women and might predict the future cardio-metabolic events.

Antidiabetic Compounds in Syzygium cumini Decoction and Ready to Serve Herbal Drink

Herbal beverages with desirable sensory attributes are an ideal way to offer consumers with phytochemicals having specific health promoting functionalities. Syzygium cumini bark decoction is used in treating diabetes mellitus in Ayurveda medicine. This work attempted to prove the presence of antidiabetic compounds in the S. cumini decoction and the ready to serve (RTS) herbal drink developed using the decoction. Activity guided fractionation of the decoction of the S. cumini was carried out by sequential extraction with organic solvents of different polarities. Thin Layer Chromatography (TLC) with authentic compounds and HPLC were performed for identification and confirmation of the compounds in the decoction and the RTS herbal drink. Presence of gallic and ellagic acids in the decoction and RTS herbal drink was proven and confirmed with HPLC. The LC UV-VIS spectra of the two compounds were identical with the corresponding spectra of the library. Further, gallic acid and umbelliferone were determined as the active compounds in the decoction by TLC and were confirmed by cochromatography with authentic compounds. The present investigation confirmed the presence of gallic acid, ellagic acid, and umbelliferone which are proven to have antidiabetic activities in the decoction and the RTS herbal drink prepared with the decoction.

Food-advanced glycation end products aggravate the diabetic vascular complications via modulating the AGEs/RAGE pathway

The aim of this study was to investigate the effects of high-advanced glycation end products (AGEs) diet on diabetic vascular complications. The Streptozocin (STZ)-induced diabetic mice were fed with high-AGEs diet. Diabetic characteristics, indicators of renal and cardiovascular functions, and pathohistology of pancreas, heart and renal were evaluated. AGEs/RAGE/ROS pathway parameters were determined. During the experiments, the diabetic mice exhibited typical characteristics including weight loss, polydipsia, polyphagia, polyuria, high-blood glucose, and low-serum insulin levels. However, high-AGEs diet effectively aggravated these diabetic characteristics. It also increased the 24-h urine protein levels, serum levels of urea nitrogen, creatinine, c-reactive protein (CRP), low density lipoprotein (LDL), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in the diabetic mice. High-AGEs diet deteriorated the histology of pancreas, heart, and kidneys, and caused structural alterations of endothelial cells, mesangial cells and podocytes in renal cortex. Eventually, high-AGEs diet contributed to the high-AGE levels in serum and kidneys, high-levels of reactive oxygen species (ROS) and low-levels of superoxide dismutase (SOD) in serum, heart, and kidneys. It also upregulated RAGE mRNA and protein expression in heart and kidneys. Our results showed that high-AGEs diet deteriorated vascular complications in the diabetic mice. The activation of AGEs/RAGE/ROS pathway may be involved in the pathogenesis of vascular complications in diabetes.

Skin Autofluorescence and Subclinical Atherosclerosis in Mild to Moderate Chronic Kidney Disease: A Case-Control Study

Advanced glycation end-products (AGEs) are increased and predict mortality in patients with chronic kidney disease (CKD) who are undergoing hemodialysis, irrespective of the presence of type 2 diabetes. However, little information exits about the relationship between AGEs and subclinical atherosclerosis at the early stages of CKD. A case-control study was performed including 87 patients with mild-to-moderate stages of CKD (glomerular filtration rate from 89 to 30 ml/min/per 1.73m²) and 87 non-diabetic non-CKD subjects matched by age, gender, body mass index, and waist circumference. Skin autofluorescence (AF), a non-invasive assessment of AGEs, was measured. The presence of atheromatous disease in carotid and femoral arteries was evaluated using vascular ultrasound, and vascular age and SCORE risk were estimated. Patients with mild-to-moderate stages of CKD showed an increase in skin AF compared with control subjects (2.5±0.6 vs. 2.2±0.4 AU, p<0.001). A skin AF value >2.0 AU was accompanied by a 3-fold increased risk of detecting the presence of an atheromathous plaque (OR 3.0, 95% CI 1.4–6.5, p = 0.006). When vascular age was assessed through skin AF, subjects with CKD were almost 12 years older than control subjects (70.3±25.5 vs. 58.5±20.2 years, p = 0.001). Skin AF was negatively correlated with glomerular filtration rate (r = -0.354, p<0.001) and LDL-cholesterol (r = -0.269, p = 0.001), and positively correlated with age (r = 0.472, p<0.001), pulse pressure (r = 0.238, p = 0.002), and SCORE risk (r = 0.451, p<0.001). A stepwise multivariate regression analysis showed that age and glomerular filtration rate independently predicted skin AF (R² = 0.289, p<0.001). Skin AF is elevated in patients with mild-to-moderate CKD compared with control subjects. This finding may be independently associated with the glomerular filtration rate and the presence of subclinical atheromatous disease. Therefore, the use of skin AF may help to accurately evaluate the real cardiovascular risk at the early stages of CKD.

Advanced glycation end-products in morbid obesity and after bariatric surgery: When glycemic memory starts to fail

BACKGROUND AND OBJECTIVE

Advanced glycation end-products (AGEs) are a marker of metabolic memory. Their levels increases when oxidative stress, inflammation, or chronic hyperglycemia exists. The role of morbid obesity in AGE levels, and the impact of bariatric surgery on them are unknown.

PATIENTS AND METHOD

An observational study with three sex- and age-matched cohorts: 52 patients with obesity, 46 patients undergoing bariatric surgery in the last 5 years, and 46 control subjects. AGE were measured using skin autofluorescence (SAF) in the forearm with an AGE Reader™ (DiagnOptics Technologies, Groningen, The Netherlands). Presence of metabolic syndrome was assessed.

RESULTS

Patients with morbid obesity had higher SAF levels (2.14±0.65AU) than non-obese subjects (1.81±0.22AU; P<.001), which was mainly attributed to obese subjects with metabolic syndrome (2.44±0.67 vs. 1.86±0.51AU; P<.001). After bariatric surgery, SAF continued to be high (2.18±0.40AU), and greater as compared to the non-obese population (P<.001). A multivariate analysis showed that age and presence of metabolic syndrome (but not sex or body mass index) were independently associated to SAF (R²=0.320).

CONCLUSION

SAF is increased in patients with morbid obesity and metabolic syndrome, mainly because of the existence of type 2 diabetes mellitus. In the first 5 years following bariatric surgery, weight loss and metabolic improvement are not associated with a parallel decrease in subcutaneous AGE levels.

AGEs/RAGE-Related Neurodegeneration: daf-16 as a Mediator, Insulin as an Ameliorant, and C. elegans as an Expedient Research Model

Advanced glycation end-products (AGEs) are nonenzymatically glycated proteins, lipids, and nucleic acids. These compounds both originate exogenously and are formed endogenously, and they are associated, along with one of their receptors (RAGE), with a variety of pathologies and neurodegeneration. Some of their deleterious effects include affecting insulin signaling and FOXO-related pathways in both receptor-dependent and -independent manners. A potential ameliorating agent for these effects is insulin, which is being studied in several in vivo and in vitro models; one of these models is C. elegans, whose maintenance, genetic malleability, and well-described longevity-related pathways make it an optimal complementary model for assessing these objectives. In the realm of neuroscience, this model is currently being used only for general assessment of neurodegeneration and shortened lifespan. We suggest that characterization of (a) the effects of AGEs/RAGE on specific neurotransmitter systems, (b) the role of the daf-2/daf-16 pathway in these neurodegenerative processes, and

The Abnormal Architecture of Healed Diabetic Ulcers Is the Result of FAK Degradation by Calpain 1

Delayed wound healing is a major complication of diabetes occurring in approximately 15% of chronic diabetic patients. It not only significantly affects patients' quality of life but also poses a major economic burden to the health care system. Most efforts have been focused on accelerating wound reepithelialization and closure. However, even after healing the quality of healed tissue in diabetics is abnormal and recurrence is common (50-75%). Thus, understanding how diabetes alters the ultimate mechanical properties of healed wounds will be important to develop more effective approaches for this condition. Focal adhesion kinase is an intracellular protein kinase that plays critical roles in cell migration, focal adhesion formation, and is an important component of cellular mechanotransduction. We have found that focal adhesion kinase expression is downregulated under a high glucose condition both in vitro and in vivo. This is secondary to increased activity of calpain 1, the primary enzyme responsible for focal adhesion kinase degradation, which becomes induced in hyperglycemia. We demonstrate that selective inhibition of calpain 1 activation improves wound healing and normalizes the mechanical properties of diabetic skin, suggesting a new therapeutic approach to prevent diabetic wound recurrence.

Evaluation of wound healing activity of cow urine ark in diabetic Wistar albino rats

Aim:

To evaluate wound healing activity of cow urine ark in diabetic rats.

Materials and Methods:

Streptozotocin-induced diabetic Wistar albino rats were randomly divided into six groups (n = 6). Three groups - diabetic control, active control (glibenclamide), and treatment (cow urine ark) were operated for excision wounds (EWs). Rats in these groups received distilled water 1 ml/day, glibenclamide 0.5 mg/kg body weight/day, and cow urine ark 5.5 ml/kg body weight/day orally till complete healing of the EWs. EWs were evaluated for wound contraction on 3^rd, 7^th, and 11^th day and for reepithelization on 11^th day. The other three groups were operated for incision wounds (IW) as well as dead space wounds (DW) in the same animal which received the above agents orally for 11 days. IWs were analyzed for wound breaking strength and DWs were analyzed for dry weight, hydroxyproline content, and histology of granulation tissue.

Results:

EWs showed significantly increased wound closure in the treatment group as compared to the diabetic as well as active control groups at 3^rd (P < 0.001) and 11^th (P < 0.05) post-wounding day and to the only diabetic control group at 7^th (P < 0.01) post-wounding day. IWs showed significant improvement in wound breaking strength in the treatment as compared to diabetic (P < 0.001) and active control (P < 0.01) groups. DWs showed significant increase in hydroxyproline content of granulation tissue in the treatment as compared to diabetic control (P < 0.001) and active control (P < 0.001) groups. Wound breaking strength and hydroxyproline content also significantly increased in the active control group compared to diabetic control (P < 0.001 and P < 0.05, respectively). Granulation tissue dry weight was significantly increased in treatment and active control groups as compared to diabetic control (P < 0.001).

Conclusion:

Cow urine ark increases granulation tissue formation as well as collagen content. Wound contraction was also significantly improved. The cow urine ark could be potentially effective in promoting healing of diabetic wounds by increasing granulation tissue formation and collagen content, however, further studies are required for its clinical application.

Identification of novel pathways in pathogenesis of ketosis in dairy cows via iTRAQ/MS

Introduction: To identify novel pathways involved in the pathogenesis of ketosis, an isobaric tag for relative and absolute quantitation/mass spectrometry was used to define differences in protein expression profiles between healthy dairy cows and those with clinical or subclinical ketosis.

Material and Methods: To define the novel pathways of ketosis in cattle, the differences in protein expression were analysed by bioinformatics. Go Ontology and Pathway analysis were carried out for enrich the role and pathway of the different expression proteins between healthy dairy cows and those with clinical or subclinical ketosis.

Results: Differences were identified in 19 proteins, 16 of which were relatively up-regulated while the remaining 3 were relatively down-regulated. Sorbitol dehydrogenase (SORD) and glyceraldehyde-3-phosphate dehydrogenase (G3PD) were up-regulated in cattle with ketosis. SORD and G3PD promoted glycolysis. These mechanisms lead to pyruvic acid production increase and ketone body accumulation.

Conclusion: The novel pathways of glycolysis provided new evidence for the research of ketosis.

Telomeres and Telomerase in Cardiovascular Diseases

Telomeres are tandem repeat DNA sequences present at the ends of each eukaryotic chromosome to stabilize the genome structure integrity. Telomere lengths progressively shorten with each cell division. Inflammation and oxidative stress, which are implicated as major mechanisms underlying cardiovascular diseases, increase the rate of telomere shortening and lead to cellular senescence. In clinical studies, cardiovascular risk factors such as smoking, obesity, sedentary lifestyle, and hypertension have been associated with short leukocyte telomere length. In addition, low telomerase activity and short leukocyte telomere length have been observed in atherosclerotic plaque and associated with plaque instability, thus stroke or acute myocardial infarction. The aging myocardium with telomere shortening and accumulation of senescent cells limits the tissue regenerative capacity, contributing to systolic or diastolic heart failure. In addition, patients with ion-channel defects might have genetic imbalance caused by oxidative stress-related accelerated telomere shortening, which may subsequently cause sudden cardiac death. Telomere length can serve as a marker for the biological status of previous cell divisions and DNA damage with inflammation and oxidative stress. It can be integrated into current risk prediction and stratification models for cardiovascular diseases and can be used in precise personalized treatments. In this review, we summarize the current understanding of telomeres and telomerase in the aging process and their association with cardiovascular diseases. In addition, we discuss therapeutic interventions targeting the telomere system in cardiovascular disease treatments.

Telomeres and Telomerase in Cardiovascular Diseases

Telomeres are tandem repeat DNA sequences present at the ends of each eukaryotic chromosome to stabilize the genome structure integrity. Telomere lengths progressively shorten with each cell division. Inflammation and oxidative stress, which are implicated as major mechanisms underlying cardiovascular diseases, increase the rate of telomere shortening and lead to cellular senescence. In clinical studies, cardiovascular risk factors such as smoking, obesity, sedentary lifestyle, and hypertension have been associated with short leukocyte telomere length. In addition, low telomerase activity and short leukocyte telomere length have been observed in atherosclerotic plaque and associated with plaque instability, thus stroke or acute myocardial infarction. The aging myocardium with telomere shortening and accumulation of senescent cells limits the tissue regenerative capacity, contributing to systolic or diastolic heart failure. In addition, patients with ion-channel defects might have genetic imbalance caused by oxidative stress-related accelerated telomere shortening, which may subsequently cause sudden cardiac death. Telomere length can serve as a marker for the biological status of previous cell divisions and DNA damage with inflammation and oxidative stress. It can be integrated into current risk prediction and stratification models for cardiovascular diseases and can be used in precise personalized treatments. In this review, we summarize the current understanding of telomeres and telomerase in the aging process and their association with cardiovascular diseases. In addition, we discuss therapeutic interventions targeting the telomere system in cardiovascular disease treatments.

Determination of Free-Form and Peptide Bound Pyrraline in the Commercial Drinks Enriched with Different Protein Hydrolysates

Pyrraline, a causative factor for the recent epidemics of diabetes and cardiovascular disease, is also employed as an indicator to evaluate heat damage and formation of advanced glycation end-products (AGEs) in foods. Peptide-enriched drinks (PEDs) are broadly consumed worldwide due to rapid rate of absorption and perceived health effects. It can be hypothesized that PED is an important source of pyrraline, especially peptide bound pyrraline (Pep-Pyr). In this study we determined free-form pyrraline (Free-Pyr) and Pep-Pyr in drinks enriched with whey protein hydrolysate (WPH), soy protein hydrolysate (SPH) and collagen protein hydrolysate (CPH). A detection method was developed using ultrahigh-performance liquid chromatography with UV-visible detector coupled with tandem mass spectrometry after solid-phase extraction (SPE). The SPE led to excellent recovery rates ranging between 93.2% and 98.5% and a high reproducibility with relative standard deviations (RSD) of <5%. The limits of detection and quantification obtained were 30.4 and 70.3 ng/mL, respectively. Pep-Pyr was identified as the most abundant form (above 96 percent) of total pyrraline, whereas Free-Pyr was present in a small proportion (less than four percent) of total pyrraline. The results indicate that PED is an important extrinsic source of pyrraline, especially Pep-Pyr. As compared with CPH- and SPH-enriched drinks, WPH-enriched drinks contained high content of Pep-Pyr. The Pep-Pyr content is associated with the distribution of peptide lengths and the amino acid compositions of protein in PEDs.

Microvasular and macrovascular complications in diabetes mellitus: Distinct or continuum?

Diabetes and related complications are associated with long-term damage and failure of various organ systems. The line of demarcation between the pathogenic mechanisms of microvascular and macrovascular complications of diabetes and differing responses to therapeutic interventions is blurred. Diabetes induces changes in the microvasculature, causing extracellular matrix protein synthesis, and capillary basement membrane thickening which are the pathognomic features of diabetic microangiopathy. These changes in conjunction with advanced glycation end products, oxidative stress, low grade inflammation, and neovascularization of vasa vasorum can lead to macrovascular complications. Hyperglycemia is the principal cause of microvasculopathy but also appears to play an important role in causation of macrovasculopathy. There is thought to be an intersection between micro and macro vascular complications, but the two disorders seem to be strongly interconnected, with micro vascular diseases promoting atherosclerosis through processes such as hypoxia and changes in vasa vasorum. It is thus imperative to understand whether microvascular complications distinctly precede macrovascular complications or do both of them progress simultaneously as a continuum. This will allow re-focusing on the clinical issues with a unifying perspective which can improve type 2 diabetes mellitus outcomes.

Added sugars drive chronic kidney disease and its consequences: A comprehensive review

The consumption of added sugars (e.g. sucrose [table sugar] and high-fructose corn syrup) over the last 200 years has increased exponentially and parallels the increased prevalence of chronic kidney disease (CKD). Data for animals and humans suggest that the consumption of added sugars leads to kidney damage and related metabolic derangements that increase cardiovascular risk. Importantly, the consumption of added sugars has been found to induce insulin resistance and increase uric acid in humans, both of which increase the conversion of glucose to fructose (i.e. fructogenesis) via the polyol pathway. The polyol pathway has recently been implicated in the contribution and progression of kidney damage, suggesting that even glucose can be toxic to the kidney via its endogenous transformation into fructose in the proximal tubule. Consuming added fructose has been shown to induce insulin resistance, which can lead to hyperglycaemia, oxidative stress, inflammation and the activation of the immune system, all of which can synergistically contribute to kidney damage. CKD guidelines should stress a reduction in the consumption of added sugars as a means to prevent and treat CKD as well as reduce CKD–related morbidity and mortality.