Role of advanced glycation end products in hypertension and cardiovascular risk: human studies

Quantity and variety of food groups consumption and the risk of hypertension in adults: a prospective cohort study

The prospective association of dietary diversity and different food groups with the risk of hypertension in the general Chinese adults has not been evaluated. We aimed to evaluate the relationship of variety and quantity of 12 major food groups with new-onset hypertension in the Chinese adults. A total of 11,118 adults from the China Health and Nutrition Survey (CHNS) were included. The study outcome was new-onset hypertension, defined as systolic blood pressure (SBP) ≥ 140 mmHg or diastolic blood pressure (DBP) ≥ 90 mmHg or diagnosed hypertension by physician or under antihypertensive treatment during the follow-up. During a median follow-up period of 6.0 years, 3867 participants occurred new-onset hypertension. There was a L-shaped relationship of dietary variety score with new-onset hypertension (P for nonlinearity < 0.001). Compared with those in the quartile 1 of dietary variety score, participants in the quartile 2-4 were associated with a significantly lower risk of hypertension (HR, 0.64; 95% CI: 0.59, 0.69). In addition, there were U-shaped associations of dairy products, vegetables, aquatic products, nuts, red meat, whole grains, refined grains, processed meat, and poultry intake with new-onset hypertension, and L-shaped associations of fruits, legumes, and eggs intake with new-onset hypertension (all P for nonlinearity < 0.001). In conclusion, there was an inverse association of dietary variety score with new-onset hypertension in the Chinese adults. Furthermore, there was a negative association between different food group intake and new-onset hypertension when food group intake was relatively low; however, the risk of hypertension increased or plateaued when the intake exceeded a certain threshold.

Consumption of processed meat but not red meat is associated with the incidence of hypertension: ELSA-Brasil cohort

OBJECTIVES

To verify the association between the consumption of red and processed meats and the incidence of hypertension in participants of the Longitudinal Study of Adult Health.

METHODS

This was a cohort with data from the baseline (2008-2010) and second wave (2012-2014) with 8,089 public workers of both sexes and different racial groups, with mean age of 49 ± 8 years (35-74 years old). Meat consumption (g/d) was estimated using a food frequency questionnaire and was divided into consumption tertiles. Hypertension was defined as systolic blood pressure ≥140 mm Hg and/or diastolic ≥90 mm Hg and/or antihypertensive medication. Cox proportional hazards models were used to estimate adjusted Hazard Ration (HRs) and 95% confidence interval (CI) for incident hypertension.

RESULTS

A total of 1186 incident cases of hypertension were identified. Even adjusting for confounders, such as urinary Na/K (sodium/potassium) ratio and BMI (body mass index), participants in the second (HR:1.19; 95% CI 1.03-1.30) and third (HR:1.30; 95% CI:1.11-1.53) tertile of processed meat consumption had a higher risk of developing hypertension than those in the first tertile. We did not find a significant association between red meat consumption and hypertension.

CONCLUSIONS

The increased risk of developing hypertension is associated with moderate and high consumption of processed meats but not with consumption of red meat.

Association Between Adherence to EAT-Lancet Diet and Risk of Hypertension: An 18-Year National Cohort Study in China

OBJECTIVE

The EAT-Lancet Commission has proposed an EAT-Lancet diet (ELD), also known as a planetary health diet (PHD), which is environmentally sustainable and promotes human health. However, the association between this diet and the risk of hypertension remains unclear. This study aimed to determine whether adherence to ELD was associated with a lower risk of hypertension.

METHODS

11,402 adults without hypertension at baseline from the China Health and Nutrition Survey were included. The PHD score was used to evaluate ELD adherence, with higher scores reflecting better compliance. Cox proportional hazards regression analysis was utilized to estimate the hazard ratio (HR) with a 95% confidence interval (CI). Additionally, a subgroup analysis was performed to identify the possible effect modifiers, and a mediation analysis was conducted to explore the mediation effects of anthropometric measurements on the association between ELD and hypertension.

RESULTS

A total of 3993 participants (35%) developed hypertension during 93,058 person-years of follow-up. In the covariate-adjusted model, hypertension risk was reduced in the highest quartile participants compared to the lowest quartile of the PHD score (adjusted HR: 0.79, 95%CI: 0.71-0.87; P-trend < 0.001), which remained significant after sensitivity analysis. Notably, the association was also observed in isolated systolic hypertension, isolated diastolic hypertension, and systolic-diastolic hypertension. Subgroup analysis revealed that the inverse association between the PHD score and hypertension risk was more pronounced in nonsmokers and high-sodium intake consumers than in smokers and low-sodium consumers (P-interaction < 0.05). Additionally, mediation analysis revealed that 23.3% of the association between the PHD score and hypertension risk was mediated by the waist-to-height ratio.

CONCLUSION

Our findings suggest that a higher adherence to ELD is associated with a lower risk of hypertension. These results emphasize that ELD may serve as a potential strategy to prevent hypertension.

Advanced glycation end products measured by skin autofluorescence and subclinical cardiovascular disease: the Rotterdam Study

BACKGROUND

Advanced glycation end products (AGEs) have been linked to cardiovascular disease (CVD), especially coronary heart disease (CHD), but their role in CVD pathogenesis remains unclear. Therefore, we investigated cross-sectional associations of skin AGEs with subclinical atherosclerosis, arterial stiffness, and hypertension after confirming their relation with CHD.

METHODS

In the population-based Rotterdam Study, skin AGEs were measured as skin autofluorescence (SAF). Prevalent MI was obtained from digital medical records. Carotid plaques, carotid intima-media thickness (IMT), coronary artery calcification (CAC), pulse wave velocity (PWV), and hypertension were assessed. Associations of SAF with endophenotypes were investigated in logistic and linear regression models adjusting for common cardiovascular risk factors. Effect modification by sex, diabetes mellitus, and chronic kidney disease (CKD) was tested.

RESULTS

3001 participants were included (mean age 73 (SD 9) years, 57% women). One unit higher SAF was associated with the presence of carotid plaques (OR 1.2 (0.92, 1.57)), a higher max IMT (0.08 SD (0.01, 0.15)), higher CAC (OR 2.2 (1.39, 3.48)), and PWV (0.09 SD (0.01, 0.16)), but not with hypertension (OR 0.99 (0.81, 1.21)). The associations with endophenotypes were more pronounced in men and participants with diabetes or CKD with significant interactions.

CONCLUSIONS

Previously documented associations between SAF and CVD, also found in our study, may be explained by the endophenotypes atherosclerosis and arterial stiffness, especially in men and individuals with diabetes or CKD, but not by hypertension. Longitudinal studies are needed to replicate these findings and to test if SAF is an independent risk factor or biomarker of CVD.

TRIAL REGISTRATION

The Rotterdam Study has been entered into the Netherlands National Trial Register (NTR; www.trialregister.nl ) and the WHO International Clinical Trials Registry Platform (ICTRP; www.who.int/ictrp/network/primary/en/ ) under shared catalogue number NTR6831.

Determination of the level of evidence for the association between different food groups/items and dietary fiber intake and the risk of cardiovascular diseases and hypertension: An umbrella review

Evidence has suggested that nutrition is a preventive factor against cardiovascular disease (CVD) risk. Because of a sharp growth in published meta-analyses and pooled analyses in recent years, a reassessment of old evidence is needed. We aimed to determine the level of evidence for the association between the consumption of different food groups/items and dietary fiber and the incidence risk of CVDs, hypertension, and atrial fibrillation from meta-analyses and pooled analyses of observational studies. Databases Scopus, PubMed/Medline, and Web of Science were searched for related studies. Fifty-eight articles met the inclusion criteria for evidence grading. In summary, grading the level of evidence showed a suggestive inverse association between the higher consumption of fruits, whole grains, fish, legumes, nuts, and dietary fibers with the incidence risk of hypertension and different types of CVD. Also, there was a probable inverse association between the higher consumption of total and low-fat dairy products and the risk of hypertension. Higher red meat consumption had a probable association with the increased risk of ischemic stroke. Higher consumption of processed meat and poultry also had a suggestive direct association with the incidence risk of stroke and hypertension. We have tried to present a comprehensive and useful overview of the level of evidence based on the most updated findings. The summary of results in the current umbrella review can be a helpful tool for nutritionists, dietitians, and researchers to establish new studies and identify research gaps in related issues.

Accelerated AGEing: The Impact of Advanced Glycation End Products on the Prognosis of Chronic Kidney Disease

Advanced glycation end products (AGEs) are aging products. In chronic kidney disease (CKD), AGEs accumulate due to the increased production, reduced excretion, and the imbalance between oxidant/antioxidant capacities. CKD is therefore a model of aging. The aim of this review is to summarize the present knowledge of AGEs in CKD onset and progression, also focusing on CKD-related disorders (cardiovascular diseases, sarcopenia, and nutritional imbalance) and CKD mortality. The role of AGEs as etiopathogenetic molecules, as well as potential markers of disease progression and/or therapeutic targets, will be discussed.

A comparison of principal component analysis, partial least-squares, and reduced-rank regressions in the identification of dietary patterns associated with hypertension: YaHS-TAMYZ and Shahedieh cohort studies

Limited data exist on the advantage of data reduction hybrid methodologies for evaluating the relationship between dietary patterns (DPs) and chronic diseases and they have led to inconsistent results. This study aimed to investigate the association between DPs extracted using principal component analysis (PCA), partial least-squares (PLS), and reduced-rank regressions (RRRs) in identifying DPs associated with hypertension (HTN) risk. The current study was conducted in the context of two cohort studies accomplished in Iran. DPs were generated using PCA, PLS, and RRR methods. Log-binomial logistic regression test was used to assess the association between DPs and the risk of HTN. From a total of 12,403 included participants aged 20-70 years, 507 incident cases of confirmed HTN were identified. The PCA-DP2 was associated with HTN in the fully adjusted model (T3 vs. T1: RR: 0.737, 95% CI: 0.57-0.93, P _trend = 0.013). The PLS-DP2 and HTN risk were inversely associated in the multivariate model (T3 vs. T1: RR: 0.704, 95% CI: 0.54-0.91, P _trend = 0.013). The RRR-DP2 was associated with an increased risk of HTN (T3 vs. T1: RR: 1.412, 95% CI: 1.11-1.80, P _trend = 0.007). Our findings suggest that the RRR method reveals stronger results in association with HTN risk. However, further investigations are required to confirm the association between DPs derived by PLS and RRR methods by incorporating biomarkers related to HTN as the response variables.

Increased serum levels of advanced glycation end products are negatively associated with relative muscle strength in patients with type 2 diabetes mellitus

BACKGROUND

In this study, we investigated whether serum levels of advanced glycation end products (AGEs) independently correlated with relative muscle strength after adjustment for clinical variables including diabetic peripheral neuropathy in patients with type 2 diabetes. Relative muscle strength was defined as muscle strength (in decinewtons, dN) divided by total muscle mass (in kg).

METHODS

We enrolled 152 ambulatory patients with type 2 diabetes. Each participant underwent measurements of muscle strength and total muscle mass. Serum levels of AGEs were determined. The Michigan Neuropathy Screening Instrument Physical Examination (MNSI-PE) was performed to assess diabetic peripheral neuropathy.

RESULTS

The participants were divided into three groups on the basis of tertiles of serum AGEs levels. Significant differences were observed among the three groups in relative handgrip strength (71.03 ± 18.22, 63.17 ± 13.82, and 61.47 ± 13.95 dN/kg in the low-tertile, mid-tertile, and high-tertile groups, respectively, P = 0.005). The relative muscle strength of the ankle plantar flexors was higher in the low-tertile group than in the mid-tertile and high-tertile groups (107.60 ± 26.53, 94.97 ± 19.72, and 94.18 ± 16.09 dN/kg in the low-tertile, mid-tertile, and high-tertile groups, respectively, P = 0.002). After adjustment for MNSI-PE score and other clinical variables in partial correlation analysis, the correlations between serum levels of AGEs and the relative muscle strength of handgrip, ankle dorsiflexor, and ankle plantar flexor remained significant. Serum AGEs level was the only variable that remained significantly related to the relative muscle strength of handgrip, ankle dorsiflexor, and ankle plantar flexor when AGEs level, fasting plasma glucose, and glycated hemoglobin (HbA_1c) were entered into multiple regression models simultaneously.

CONCLUSIONS

After adjustment for multiple factors including diabetic peripheral neuropathy, this study demonstrated that increased serum levels of AGEs were independently associated with decreased relative muscle strength in patients with type 2 diabetes. Compared with fasting plasma glucose and HbA_1c, serum level of AGEs is more strongly associated with relative muscle strength.

Dietary N-epsilon-carboxymethyllysine as for a major glycotoxin in foods: A review

N-epsilon-carboxymethyllysine (CML), as a potential glycotoxin and general marker for dietary advanced glycation end products (dAGEs), exists in raw food and is formed via various formation routes in food processing such as Maillard reaction between the reducing sugars and amino acids. Although comprehensive cause-effect proof is not available yet, current research suggests a potential risk of chronic diseases such as diabetes is associated with exogenous CML. Thus, CML is causing public health concerns regarding its dietary exposure, but there is a lack of explicit guidance for understanding if it is detrimental to human health. In this review, inconsistent results of dietary CML contributed to chronic disease are discussed, available concentrations of CML in consumed foods are evaluated, measurements for dietary CML and relevant analytic procedures are listed, and the possible mitigation strategies for protecting against CML formation are presented. Finally, the main challenges and future efforts are highlighted. Further studies are needed to extend the dietary CML database in a wide category of foods, apply new identifying methods, elucidate the pathogenic mechanisms, assess its detrimental role in human health, and propose standard guidelines for processed food.

AGE/RAGE in diabetic kidney disease and ageing kidney

Diabetic kidney disease (DKD) is the primary cause of chronic kidney disease that inevitably progress to end-stage kidney disease. Intervention strategies such as blood glucose control is effective for preventing DKD, but many patients with DKD still reach end-stage kidney disease. Although comprehensive mechanisms shed light on the progression of DKD, the most compelling evidence has highlighted that hyperglycemia-related advanced glycation end products (AGEs) formation plays a central role in the pathogenesis of DKD. Pathologically, accumulation of AGEs-mediated receptor for AGEs (RAGE) triggers oxidative stress and inflammation, which is the major deleterious effect of AGEs in host and intestinal microenvironment of diabetic and ageing conditions. The activation of AGEs-mediated RAGE could evoke nicotinamide adenine dinucleotide phosphate oxidase-induced reactive oxygen and nitrogen species production and subsequently give rise to oxidative stress in DKD and ageing kidney. Therefore, targeting RAGE with its ligands mediated oxidative stress and chronic inflammation is considered as an additional intervention strategy for DKD and ageing kidney. In this review, we summarize AGEs/RAGE-mediated oxidative stress and inflammation signaling pathways in DKD and ageing kidney, discussing opportunities and challenges of targeting at AGEs/RAGE-induced oxidative stress that could hold the promising potential approach for improving DKD and ageing kidney.

The Pharmacological Activity of the Wenjing Decoction in Recurrent Spontaneous Abortion

Background

Recurrent spontaneous abortion (RSA) is intractable infertility and can be ameliorated with the use of traditional Chinese medicine preparation, the Wenjing decoction. This study aimed to identify the therapeutic mechanism of Wenjing decoction on specific target proteins involved in RSA.

Methods

Wenjing decoction contains Wuzhuyu, Danggui, Chuanxiong, Guizhi, Shengjiang, Banxia, Gancao, Ejiao, Mudanpi, Chishao, Dangshen, and Maidong. Using TCMSP and BATMAN databases, we queried for active ingredients and predicted their target proteins by BATMAN. Using the edgeR package, we analyzed the differentially expressed genes (DEGs) in the GSE121950 database between control samples and RSA (n = 3). The interaction between DEGs and the predicted target proteins was identified by the Venn diagram. Using the Cytoscape software and clusterProfiler package, enrichment analysis was conducted for the intersected target proteins. Additionally, the protein-protein interaction (PPI) network and pharmacological network were generated using the Cytoscape software.

Results

In total, 31, 2, 7, 7, 5, 13, 93, 11, 29, and 21 active ingredients were identified from Wuzhuyu, Danggui, Chuanxiong, Guizhi, Shengjiang, Banxia, Gancao, Mudanpi, Chishao, and Dangshen, respectively. Additionally, 100 intersected target proteins were revealed by the Venn diagram. Moreover, 98 functional terms and 24 pathways (including C-type lectin receptor signaling pathway, chemokine signaling pathway, leukocyte transendothelial migration, fluid shear stress, and atherosclerosis, and AGE-RAGE signaling pathway in diabetic complications) were enriched. In the PPI network, 10 proteins involved in these five pathways were identified, namely, TNF-α (tumor necrosis factor-α), IL-10 (interleukin-10), TLR4 (Toll-like receptor 4), JUN (Jun proto-oncogene), IL-1B (interleukin-1-beta), CYBB (cytochrome b558 heavy chain gene), PTGS2 (prostaglandin-endoperoxide synthase 2), APOE (apolipoprotein E), SPI1 (salmonella pathogenicity island 1), and MPO (myeloperoxidase) which showed higher degrees.

Conclusion

The abovementioned genes and pathways might be involved in the pharmacological activity of Wenjing decoction in RSA.

Mitochondrial Dysfunction: Cause or Consequence of Vascular Calcification?

Mitochondria are crucial bioenergetics powerhouses and biosynthetic hubs within cells, which can generate and sequester toxic reactive oxygen species (ROS) in response to oxidative stress. Oxidative stress-stimulated ROS production results in ATP depletion and the opening of mitochondrial permeability transition pores, leading to mitochondria dysfunction and cellular apoptosis. Mitochondrial loss of function is also a key driver in the acquisition of a senescence-associated secretory phenotype that drives senescent cells into a pro-inflammatory state. Maintaining mitochondrial homeostasis is crucial for retaining the contractile phenotype of the vascular smooth muscle cells (VSMCs), the most prominent cells of the vasculature. Loss of this contractile phenotype is associated with the loss of mitochondrial function and a metabolic shift to glycolysis. Emerging evidence suggests that mitochondrial dysfunction may play a direct role in vascular calcification and the underlying pathologies including (1) impairment of mitochondrial function by mineral dysregulation i.e., calcium and phosphate overload in patients with end-stage renal disease and (2) presence of increased ROS in patients with calcific aortic valve disease, atherosclerosis, type-II diabetes and chronic kidney disease. In this review, we discuss the cause and consequence of mitochondrial dysfunction in vascular calcification and underlying pathologies; the role of autophagy and mitophagy pathways in preventing mitochondrial dysfunction during vascular calcification and finally we discuss mitochondrial ROS, DRP1, and HIF-1 as potential novel markers and therapeutic targets for maintaining mitochondrial homeostasis in vascular calcification.

miR-21-3p regulates AGE/RAGE signalling and improves diabetic atherosclerosis

To explore the effects of miR-21-3p on diabetic atherosclerosis. Using enzyme-linked immunosorbent assay (ELISA), we also detected the levels of soluble receptor for advanced glycation endproducts RAGE (sRAGE) in the cellular supernatant of vascular endothelial cells after transfecting them with adenovirus vector having miR-21-3p mimic or inhibitor. We found decrease in the expression levels of miR-21-3p in vascular endothelial cells (VECs) induced by high-concentration glucose. We also observed that the introduction of miR-21-3p mimic significantly increased the expression of ADAM10 in the VECs. Similarly, significantly higher levels of sRAGE were found in the cultured supernatant after administration of miR-21-3p mimic in human vein endothelial cells. The production of reactive oxygen species and expression of inflammatory cytokines in VECs induced by LPS and high-concentration glucose were significantly decreased after administration of miR-21-3p. in vivo studies revealed that intravenous injection of miR-21-3p at regular intervals would reduce the area of atherosclerotic lesion and elevate the serum levels of sRAGE in atherosclerotic diabetic mice. miR-21-3p may be beneficial in diabetic atherosclerosis by promoting the cleaved form of sRAGE and inhibition of RAGE/NADPH oxidase signalling depending on the increased expression of ADAM10. SIGNIFICANCE OF THE STUDY: We identified a novel microRNA, miR-21-3p, which is characteristically at elevated levels in serum derived from diabetic patients and responsible for target degradation of ADAM10 mRNA. Further, we show that miR-21-3p aggravates the atherosclerotic lesion via dysfunction of the ectodomain shedding of molecular binding RAGE in the diabetic atherosclerotic mice.

Relationship among urinary advanced glycation-end products, skeletal muscle mass and physical performance in community-dwelling older adults

AIM

Advanced glycation end-products are important factors in muscle function and physical performance among older adults. However, the association between sarcopenia and urinary carboxymethyl-lysine (uCML) levels remains unclear. The present study aimed to investigate the relationship among uCML levels, skeletal muscle mass, physical performance and sarcopenia among community-dwelling older adults.

METHODS

This work was a community-based cross-sectional study. The participants were recruited from the Taichung Community Health Study-Elderly and were followed up until 2017. A total of 104 participants underwent dual-energy X-ray absorptiometry examination, physical performance tests and measurement of uCML levels. After the natural log transformation of the uCML levels, Pearson's correlation coefficient and a general linear model were used for statistical analysis.

RESULTS

The mean uCML levels of older men and women were 1.34 μg/mg and 1.63 μg/mg creatinine, respectively. After multivariate adjustment, grip strength among older women significantly decreased as uCML levels increased. Participants with uCML levels and Timed Up and Go test values higher than the median had a 13.76-fold risk of acquiring sarcopenia compared with those whose corresponding variables were lower than the median after adjusting for age, sex, body fat percentage, and serum creatinine and blood urea nitrogen levels.

CONCLUSIONS

uCML levels were negatively associated with grip strength among older women. The joint association of uCML and Timed Up and Go test values was correlated with the risk of acquiring sarcopenia among older adults. This finding suggests that uCML levels can be used as a biomarker for screening sarcopenia and as a strategy for treating sarcopenia. Geriatr Gerontol Int 2019; 19: 1017-1022.

New Insights into the Process of Placentation and the Role of Oxidative Uterine Microenvironment

For a successful pregnancy to occur, a predecidualized receptive endometrium must be invaded by placental differentiated cells (extravillous trophoblast cells (EVTs)) and, at the same time, continue decidualization. EVT invasion is aimed at anchoring the placenta to the maternal uterus and ensuring local blood supply increase necessary to provide normal placental and foetal development. The first is achieved by migrating through the maternal endometrium and deeper into the myometrium, while the second by transforming uterine spiral arteries into large vessels. This process is a tightly regulated battle comprising interests of both the mother and the foetus. Invading EVTs are required to perform a scope of functions: move, adhere, proliferate, differentiate, interact, and digest the extracellular matrix (ECM); tolerate hypoxia; transform the maternal spiral arteries; and die by apoptosis. All these functions are modulated by their surrounding microenvironment: oxygen, soluble factors (e.g., cytokines, growth factors, and hormones), ECM proteins, and reactive oxygen species. A deeper comprehension of oxidative uterine microenvironment contribution to trophoblast function will be addressed in this review.

Baijiu Vinasse Extract Scavenges Glyoxal and Inhibits the Formation of Nε-Carboxymethyllysine in Dairy Food

The inhibitory effects of baijiu vinasse extract and its phenolic acid compounds on the N^ε-carboxymethyllysine (CML) formation from dairy food were investigated. The inhibitory effect of the baijiu vinasse extract against CML formation was 43.2% in the casein and D-glucose model, which used 6 mL of the 70% acetone extract at 60 °C for 40 min. The HPLC-MS/MS profiles of the vinasse extract indicated that vanillic, chlorogenic, p-coumaric, sinapic, caffeic, ferulic, and syringic acids were seven major phenolic acid compounds. Furthermore, the inhibitory mechanism of the phenolic acid compounds in the model of dairy food was discussed by the trapping and scavenging of glyoxal. The results of this study exhibit that seven major antioxidant phenolic acid compounds may play important roles in the antioxidant activity and CML inhibition of the vinasse extract in a model of dairy foods.

Biofilm Formation of Staphylococcus aureus under Food Heat Processing Conditions: First Report on CML Production within Biofilm

This study aimed to evaluate the Staphylococcus aureus biofilm formation and Nε-carboxymethyl-lysine generation ability under food heat processing conditions including pH (5.0-9.0), temperature (25 °C, 31 °C, 37 °C, 42 °C and 65 °C), NaCl concentration (10%, 15% and 20%, w/v) and glucose concentration (0.5%, 1%, 2%, 3%, 5%, 10%, w/v). S. aureus biofilm genetic character was obtained by PCR detecting atl, ica operon, sasG and agr. Biofilm biomass and metabolic activity were quantified with crystal violet and methyl thiazolyl tetrazolium staining methods. S. aureus biofilm was sensitive to food heat processing conditions with 37 °C, pH 7.0, 2% glucose concentration (w/v) and 10% NaCl concentration (w/v) were favorable conditions. Besides, free and bound Nε-carboxymethyl-lysine level in weak, moderate and strong biofilm were detected by optimized high performance liquid chromatography tandem mass spectrometry. Nε-carboxymethyl-lysine level in S. aureus biofilm possessed a significant gap between strong, moderate and weak biofilm strains. This investigation revealed the biological and chemical hazard of Staphylococcus aureus biofilm to food processing environment.

Role of advanced glycation end products in mobility and considerations in possible dietary and nutritional intervention strategies

Advanced glycation end products (AGEs), a group of compounds that are formed by non-enzymatic reactions between carbonyl groups of reducing sugars and free amino groups of proteins, lipids or nucleic acids, can be obtained exogenously from diet or formed endogenously within the body. AGEs accumulate intracellularly and extracellularly in all tissues and body fluids and can cross-link with other proteins and thus affect their normal functions. Furthermore, AGEs can interact with specific cell surface receptors and hence alter cell intracellular signaling, gene expression, the production of reactive oxygen species and the activation of several inflammatory pathways. High levels of AGEs in diet as well as in tissues and the circulation are pathogenic to a wide range of diseases. With respect to mobility, AGEs accumulate in bones, joints and skeletal muscles, playing important roles in the development of osteoporosis, osteoarthritis, and sarcopenia with aging. This report covered the related pathological mechanisms and the potential pharmaceutical and dietary intervention strategies in reducing systemic AGEs. More prospective studies are needed to determine whether elevated serum AGEs and/or skin autofluorescence predict a decline in measures of mobility. In addition, human intervention studies are required to investigate the beneficial effects of exogenous AGEs inhibitors on mobility outcomes.

Skin autofluorescence is associated with vascular complications in patients with type 2 diabetes

AIMS

Tissue accumulatedadvanced glycation end products (AGEs) can be evaluated non-invasively by an autofluorescence reader as skin autofluorescence (skin AF)·The present study investigated whether skin AF is associated with diabetic micro- and macroangiopathies in Japanese patients with type 2 diabetes mellitus (T2DM).

METHODS

Skin AF was measured in 193 enrolled Japanese patients with T2DM and 24 enrolled healthy non-diabetic subjects by using the AGE reader®. Diabetic micro- and macroangiopathies were evaluated in the T2DM patients.

RESULTS

Skin AF was significantly increased in patients with T2DM than in age- and sex-matched non-diabetic controls (2.35 ± 0.51 [mean ± SD] and 1.91 ± 0.29, respectively, p = 0.001). In subjects with T2DM, skin AF was associated with age, pack-years of smoking, and eGFR (estimated glomerular filtration rate) independently. Skin AF was significantly increased in patients with diabetic retinopathy, neuropathy, nephropathy, and macroangiopathy than in those without them, and significantly associated with the number of diabetic complications. Moreover, skin AF was an independent predictor for diabetic retinopathy, neuropathy, and nephropathy but not macroangiopathy, after adjusting for major traditional risk factors.

CONCLUSIONS

Skin AF is an independent predictor for diabetic retinopathy, neuropathy and nephropathy in Japanese patients with T2DM.

A pyridoindole antioxidant SMe1EC2 regulates contractility, relaxation ability, cation channel activity, and protein-carbonyl modifications in the aorta of young and old rats with or without diabetes mellitus

We studied the effects of treatment with SMe1EC, a hexahydropyridoindole antioxidant, on vascular reactivity, endothelial function, and oxidonitrosative stress level of thoracic aorta in young and old rats with or without diabetes mellitus. The rats were grouped as young control (YC 3 months old), old control (OC 15 months old), young diabetic (YD), old diabetic (OD), young control treated (YCT), old control treated (OCT), young diabetic treated (YDT), and old diabetic treated (ODT). Diabetes was induced by streptozotocin injection and subsequently SMe1EC2 (10 mg/kg/day, p.o.) was administered to YCT, OCT, YDT, and ODT rats for 5 months. In young and old rats, diabetes resulted in hypertension, weight loss, hyperglycemia, and hypertriglyceridemia, which were partially prevented by SMe1EC2. SMe1EC2 also inhibited the diabetes-induced increase in aorta levels of AGEs (advanced glycosylation end-protein adducts), 4-HNE (4-hydroxy-nonenal-histidine), 3-NT (3-nitrotyrosine), and RAGEs (receptors for AGEs). The contractions of the aorta rings to phenylephrine (Phe) and KCL did not significantly change, but acetylcholine (ACh) and salbutamol relaxations were reduced in OC compared to YC rats. Diabetes induction increased Phe contractions in YC and OC rats, KCL contractions in YC rats, and did not cause further inhibition in already inhibited ACh and salbutamol relaxations in OC rats. We have achieved the lowest levels of ACh relaxation in YD rats compared to other groups. SMe1EC2 did not change the response of aorta to ACh, salbutamol and Phe in YC rats, and ameliorated ACh relaxations in OC and YD but not in OD rats. In YDT and ODT rats, increased Phe and KCL contractions, high blood pressure, and impaired salbutamol relaxations were amended by SMe1EC2. Phe contractions observed in YD and OD rats as well as KCl contractions observed in OC rats were the lowest levels when the rats were treated with SMe1EC2. When the bath solution was shifted to cyclopiazonic acid (CYP) or CYP plus Ca²⁺-free medium, the contraction induced by a single dose of Phe (3 × 10^-6 M) was more inhibited in YD and OD than in YC but not in OC rats. In SMe1EC2-treated rats, neither the presence of CFM nor CFM plus CYP exhibited a significant change in response of aorta to a single dose of Phe. These findings suggest that α1-adrenergic receptor signaling is activated in both age groups of diabetic rats, diabetes activates K⁺-depolarization and calcium mobilization via Ca_V especially in the aorta of young rats, and sensitizes the aorta of old rats to the regulating effect of SMe1EC2. ACh relaxations were inhibited in YC rats, increased in OC rats and unchanged in YD and OD rats when aortic rings pretreated with TEA, an inhibitor of calcium-activated K⁺ channels (K_Ca), or 4-aminopyridine (4-AP), an inhibitor of voltage-sensitive K⁺ channels (K_V). ACh relaxations were inhibited in YCT, OCT, and YDT rats in the presence of 4-AP or TEA. In ODT rats, 4-AP did not change ACh relaxation but TEA inhibited. These findings suggest that the contribution of K_v and K_Ca to ACh relaxation is likely upregulated by SMe1EC2 when the relaxations were inhibited by aging or diabetes. We conclude that SMe1EC2 might be a promising agent for aging and diabetes related vascular disorders.

Advanced glycation end products and risk of hypertension in Iranian adults: Tehran lipid and glucose study

Background:

Elevated blood pressure is still one of the major risk factors for diseases and disabilities and also a public health challenge worldwide. In the present longitudinal study, we aimed to evaluate the association between risk of hypertension and dietary advanced glycation end products (AGEs) as a recently discussed potential risk factor.

Materials and Methods:

Dietary assessment of 1775 participants in the third phase of Tehran lipid and glucose study to obtain dietary intake of AGEs was performed using a validated semi-quantitative food frequency questionnaire, and they were followed up for a mean duration of approximately 6 years. To determine the incidence of hypertension across quartiles of AGEs intake, logistic regression models with adjustment for potential confounding variables were used. All statistical analyses were conducted using SPSS, and P < 0.05 was considered statistically significant.

Results:

Higher hypertension occurrence risk was generally attributed to higher AGEs intake quartiles after adjusting for age in men (odds ratio [OR] = 1.48, 95% confidence interval [CI] = 1.11–1.52, P = 0.038) and additional adjustment for smoking, drugs, and physical activity in women (OR = 1.38%–95% CI = 1.09–1.42, P = 0.042). Moreover, across the increasing trend of dietary AGEs intake, the percentage of fat intake increased and that of carbohydrate significantly decreased (P < 0.0001).

Conclusion:

In conclusion, it is highly recommended to limit dietary AGEs consumption to prevent and manage hypertension and its complications.

Food Groups and Risk of Hypertension: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies

The aim of this systematic review and meta-analysis was to summarize the evidence on the relation of the intakes of 12 major food groups, including whole grains, refined grains, vegetables, fruits, nuts, legumes, eggs, dairy, fish, red meat, processed meat, and sugar-sweetened beverages (SSBs) with the risk of hypertension. PubMed, Scopus, and Web of Science were searched systematically until June 2017 for prospective studies having quantitatively investigated the above-mentioned foods. We conducted meta-analysis on the highest compared with the lowest intake categories and linear and nonlinear dose-response meta-analyses to analyze the association. Summary RRs and 95% CIs were estimated by using a random-effects model. Overall, 28 reports were included in the meta-analysis. An inverse association for the risk of hypertension was observed for 30 g whole grains/d (RR: 0.92; 95% CI: 0.87, 0.98), 100 g fruits/d (RR: 0.97; 95% CI: 0.96, 0.99), 28 g nuts/d (RR: 0.70; 95% CI: 0.45, 1.08), and 200 g dairy/d (RR: 0.95; 95% CI: 0.94, 0.97), whereas a positive association for 100 g red meat/d (RR: 1.14; 95% CI: 1.02, 1.28), 50 g processed meat/d (RR: 1.12; 95% CI: 1.00, 1.26), and 250 mL SSB/d (RR: 1.07; 95% CI: 1.04, 1.10) was seen in the linear dose-response meta-analysis. Indication for nonlinear relations of the intakes of whole grains, fruits, fish, and processed meats with the risk of hypertension was detected. In summary, this comprehensive dose-response meta-analysis of 28 reports identified optimal intakes of whole grains, fruits, nuts, legumes, dairy, red and processed meats, and SSBs related to the risk of hypertension. These findings need to be seen under the light of very-low to low quality of meta-evidence. However, the findings support the current dietary guidelines in the prevention of hypertension.

TRB3 mediates advanced glycation end product-induced apoptosis of pancreatic β-cells through the protein kinase C β pathway

Advanced glycation end products (AGEs), which accumulate in the body during the development of diabetes, may be one of the factors leading to pancreatic β-cell failure and reduced β-cell mass. However, the mechanisms responsible for AGE‑induced apoptosis remain unclear. This study identified the role and mechanisms of action of tribbles homolog 3 (TRB3) in AGE-induced β-cell oxidative damage and apoptosis. Rat insulinoma cells (INS-1) were treated with 200 µg/ml AGEs for 48 h, and cell apoptosis was then detected by TUNEL staining and flow cytometry. The level of intracellular reactive oxygen species (ROS) was measured by a fluorescence assay. The expression levels of receptor of AGEs (RAGE), TRB3, protein kinase C β2 (PKCβ2) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4 (NOX4) were evaluated by RT-qPCR and western blot analysis. siRNA was used to knockdown TRB3 expression through lipofection, followed by an analysis of the effects of TRB3 on PKCβ2 and NOX4. Furthermore, the PKCβ2-specific inhibitor, LY333531, was used to analyze the effects of PKCβ2 on ROS levels and apoptosis. We found that AGEs induced the apoptosis of INS-1 cells and upregulated RAGE and TRB3 expression. AGEs also increased ROS levels in β-cells. Following the knockdown of TRB3, the AGE-induced apoptosis and intracellular ROS levels were significantly decreased, suggesting that TRB3 mediated AGE-induced apoptosis. Further experiments demonstrated that the knockdown of TRB3 decreased the PKCβ2 and NOX4 expression levels. When TRB3 was knocked down, the cells expressed decreased levels of PKCβ2 and NOX4. The PKCβ2‑specific inhibitor, LY333531, also reduced AGE-induced apoptosis and intracellular ROS levels. Taken together, our data suggest that TRB3 mediates AGE-induced oxidative injury in β-cells through the PKCβ2 pathway.

The systemic nature of CKD

The accurate definition and staging of chronic kidney disease (CKD) is one of the major achievements of modern nephrology. Intensive research is now being undertaken to unravel the risk factors and pathophysiologic underpinnings of this disease. In particular, the relationships between the kidney and other organs have been comprehensively investigated in experimental and clinical studies in the last two decades. Owing to technological and analytical limitations, these links have been studied with a reductionist approach focusing on two organs at a time, such as the heart and the kidney or the bone and the kidney. Here, we discuss studies that highlight the complex and systemic nature of CKD. Energy balance, innate immunity and neuroendocrine signalling are highly integrated biological phenomena. The diseased kidney disrupts such integration and generates a high-risk phenotype with a clinical profile encompassing inflammation, protein-energy wasting, altered function of the autonomic and central nervous systems and cardiopulmonary, vascular and bone diseases. A systems biology approach to CKD using omics techniques will hopefully enable in-depth study of the pathophysiology of this systemic disease, and has the potential to unravel critical pathways that can be targeted for CKD prevention and therapy.

Carboxymethyl-lysine: thirty years of investigation in the field of AGE formation

In 1985 carboxymethyl-lysine (CML), the first glycoxidation product, was discovered by Dr Ahmed while trying to identify the major products formed in reactions of glucose with lysine under physiological conditions. From that moment, a significant number of researchers have joined efforts to study its formation routes both in foods and in living beings, and the possibility of the existence of an additive action between food-occurring and in vivo produced CML and to explore all the implications associated with its appearance in the biological systems, regardless of its origin. This review presents interesting information on the latest advances in the research on CML sources, mitigation strategies, intake, metabolism and body fluid and tissue delivery, its possible in vivo synergy with highly modified advanced glycation end products-protein, and the physio-pathological implications derived from the presence of this compound in body fluids and tissues.

Skin Autofluorescence is Associated with Early-stage Atherosclerosis in Patients with Type 1 Diabetes

AIM

Accumulation level of fluorescent advanced glycation end products (AGEs) in the skin can be measured non-invasively as skin autofluorescence (skin AF) by autofluorescence reader. The aim of this study was to assess possible associations between skin AF and diabetic complications, especially early-stage atherosclerosis, in Japanese type 1 diabetic patients.

METHODS

Skin AF was measured by AGE reader® in 105 Japanese type 1 diabetic patients (34 men and 71 women, aged 37.4±12.4 years (±SD)) and 23 age-matched healthy non-diabetic subjects. Ultrasonic carotid intima-media thickness (IMT), ankle-brachial index (ABI), and brachial ankle pulse wave velocity (baPWV) were evaluated as indices of early-stage diabetic macroangiopathy. Urinary albumin-to-creatinine ratio (UACR), the coefficient of variation of R-R intervals (CVR-R), and presence of retinopathy were also evaluated.

RESULTS

Skin AF values were significantly higher in type 1 diabetic patients than in healthy controls (2.07±0.50 (mean±SD) and 1.90±0.26, respectively, p=0.024). Skin AF was associated with carotid IMT (r=0.446, p＜0.001) and baPWV (r=0.450, p＜0.001), but not with ABI (r=－0.019, p=0.8488). Notably, skin AF was an independent risk factor for IMT thickening. Similarly, skin AF was associated with log (UACR) (r=0.194, p=0.049) and was an independent risk factor for UACR. Furthermore, skin AF values were significantly higher in patients with diabetic retinopathy than in those without (2.21±0.08 and 1.97±0.06, respectively, p=0.020).

CONCLUSIONS

Skin AF was significantly associated with the presence and/or severity of diabetic complications and was an independent risk factor for carotid atherosclerosis.

Oxidative stress signaling to chromatin in health and disease

Oxidative stress has a significant impact on the development and progression of common human pathologies, including cancer, diabetes, hypertension and neurodegenerative diseases. Increasing evidence suggests that oxidative stress globally influences chromatin structure, DNA methylation, enzymatic and non-enzymatic post-translational modifications of histones and DNA-binding proteins. The effects of oxidative stress on these chromatin alterations mediate a number of cellular changes, including modulation of gene expression, cell death, cell survival and mutagenesis, which are disease-driving mechanisms in human pathologies. Targeting oxidative stress-dependent pathways is thus a promising strategy for the prevention and treatment of these diseases. We summarize recent research developments connecting oxidative stress and chromatin regulation.

Long-term intake of animal flesh and risk of developing hypertension in three prospective cohort studies

OBJECTIVE

Prospective data are scarce on the relation of red meat, seafood, and poultry consumption with hypertension risk. Although red and processed meats are generally considered to have adverse cardiovascular consequences, seafood is believed to be protective and poultry's effect is controversial.

METHODS

We prospectively examined the independent association of long-term intake of animal flesh with incident hypertension in three longitudinal cohort studies of nonhypertensive individuals: Nurses' Health Study (NHS, n = 62 273 women), Nurses' Health Study II (NHS II, n = 88 831 women), and Health Professionals Follow-Up Study (HPFS, n = 37 414 men). We used multivariable Cox proportional hazards regression to study the associations of different types of animal flesh with the risk of developing hypertension while controlling for other hypertension risk factors. We then used fixed-effects meta-analysis to derive pooled estimates of effect.

RESULTS

Compared with participants whose consumption was less than 1 serving/month, the pooled hazard ratios among those whose intake was at least 1 serving/day were 1.30 (95% confidence interval 1.23-1.39) for total meat (a combination of processed and unprocessed red meat), 1.22 (1.12-1.34) for poultry, and 1.05 (0.98-1.13) for seafood. Seafood was associated with an increased risk of hypertension in HPFS and NHS II, but not NHS. Consumption of any animal flesh at least 1 serving/day was associated with an increased hypertension risk [pooled hazard ratio = 1.30 (1.16-1.47)].

CONCLUSION

Long-term intake of meat and poultry were associated with increased risk of hypertension. In contrast to our hypothesis, we found a weak but significant trend toward an increased risk of hypertension with increasing seafood consumption.

Eplerenone restores 24-h blood pressure circadian rhythm and reduces advanced glycation end-products in rhesus macaques with spontaneous hypertensive metabolic syndrome

Hypertension is often associated with metabolic syndrome (MetS), and serves as a risk factor of MetS and its complications. Blood pressure circadian rhythm in hypertensive patients has been suggested to contribute to cardiovascular consequences and organ damage of hypertension. But circadian changes of BP and their response to drugs have not been clearly investigated in non-human primates (NHPs) of MetS with hypertension. Here, we identified 16 elderly, hypertensive MetS rhesus monkeys from our in-house cohort. With implanted telemetry, we investigate BP changes and its circadian rhythm, together with the effect of antihypertensive drugs on BP and its diurnal fluctuation. MetS hypertensive monkeys displayed higher BP, obesity, glucose intolerance, and dyslipidemia. We also confirmed impaired 24-h BP circadian rhythm in MetS hypertensive monkeys. Importantly, Eplerenone, a mineralocorticoid receptor blocker, exerts multiple beneficial effects in MetS hypertensive monkeys, including BP reduction, 24-h BP circadian rhythm restoration, and decreased plasma concentration of inflammation factors and advanced glycation end-products. In summary, we identified a naturally-developed hypertensive MetS NHP model, which is of great value in the studies on pathogenesis of MetS-associated hypertension and development of novel therapeutic strategies. We also provided multiple novel mechanistic insights of the beneficial effect of Eplerenone on MetS with hypertension.

Impact of Variety and Agronomic Factors on Crude Protein and Total Lysine in Chicory; N(ε)-Carboxymethyl-lysine-Forming Potential during Drying and Roasting

During the heat treatment of coffee and its substitutes some compounds potentially deleterious to health are synthesized by the Maillard reaction. Among these, N(ε)-carboxymethyl-lysine (CML) was detected at high levels in coffee substitutes. The objective of this study was to evaluate the impact of changes in agricultural practice on the lysine content present in chicory roots and try to limit CML formation during roasting. Of the 24 varieties analyzed, small variations in lysine content were observed, 213 ± 8 mg/100 g dry matter (DM). The formation of lysine tested in five commercial varieties was affected by the nitrogen treatment with mean levels of 176 ± 2 mg/100 g DM when no fertilizer was added and 217 ± 7 mg/100 g DM with a nitrogen supply of 120 kg/ha. The lysine content of fresh roots was significantly correlated to the concentration of CML formed in roasted roots (r = 0.51; p < 0.0001; n = 76).

Kinetics of N(ε)-(carboxymethyl)lysine formation in aqueous model systems of sugars and casein

This study investigated the formation of N(ε)-carboxymethyllysine (CML) in two caseinate solutions containing: (1) glucose, (2) lactose, each heated at 120 °C and 130 °C. At both heating temperatures, CML concentration in lactose-caseinate solution was higher than in glucose-caseinate solution. In both solutions, more CML was formed at 130 °C than at 120 °C. Using multiresponse modelling, two degradation routes for the sugars were confirmed: (1) isomerisation of glucose or lactose and subsequent degradation via Lobry de Bruyn-Alberda van Ekenstein (LA) arrangement; (2) the Maillard reaction between the reducing sugar and lysine residues. Modelling results suggested that CML was not formed from oxidation of the reducing sugars, but from the Maillard reaction via the Amadori rearrangement product. Since CML appeared to be thermally unstable under the current study conditions, it may not be a perfect indicator for heat damage of processed foods. This is the first study in which CML formation was linked to available information on the Maillard reaction via multiresponse modelling.

Abnormal levels of age-elastin derived peptides in sera of diabetic patients with arterial hypertension

Introduction

An important factor in vascular wall alterations is degradation of elastic fiber major protein – elastin. As a result, elastin derived peptides (EDP) are found in circulation. Advanced glycation might also involve elastin, because it is a protein with slow metabolism. The aim of our study was to measure serum levels of glycated elastin derived peptides (AGE-EDP) of elastin in patients with type 2 diabetes mellitus (T2DM) and arterial hypertension (AH).

Material and methods

We adapted an ELISA technique for the determination of AGE-EDP. Sera of 93 patients with T2DM and AH (mean age 61.4 ±11.3 years, diabetes duration 9.88 ±3.12 years; hypertension duration 9.28 ±4.98) were tested. These values were compared to 42 age- and sex-matched controls. Diabetics were divided in two groups according to presence – Group 1 (n = 67) or absence – Group 2 (n = 26) of microangiopathy.

Results

Patients with T2DM and AH showed statistically significantly higher levels of AGEEDP in comparison with healthy controls 0.060 (0.053÷0.065) vs. 0.039 (0.031÷0.044) (KW = 35.2; p < 0.0001). Group 1 showed significantly higher levels of AGE-EDP than the control group 0.069 (0.051÷0.070) vs. 0.039 (0.031÷0.044) (KW = 33.0; p < 0.0001). Group 2 also showed significantly higher levels of AGE-EDP than controls 0.058 (0.049÷0.064) vs. 0.039 (0.031÷0.044) (KW = 22.1; p < 0.0001). AGE-EDP showed a correlation with an insulin dose (r = –0.28; p = 0.05), systolic blood pressure (r = 0.25; p = 0.01), BMI (r = 0.39; p = 0.01) and retinopathy (r = 0.18; p = 0.05).

Conclusions

The measurement of non-invasive markers of elastin glycation may be useful in monitoring development of vascular wall alterations and therapeutic interventions.

Resveratrol and cardiovascular health--promising therapeutic or hopeless illusion?

Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is a natural polyphenolic compound that exists in Polygonum cuspidatum, grapes, peanuts and berries, as well as their manufactured products, especially red wine. Resveratrol is a pharmacologically active compound that interacts with multiple targets in a variety of cardiovascular disease models to exert protective effects or induce a reduction in cardiovascular risks parameters. This review attempts to primarily serve to summarize the current research findings regarding the putative cardioprotective effects of resveratrol and the molecular pathways underlying these effects. One intent is to hopefully provide a relatively comprehensive resource for clues that may prompt ideas for additional mechanistic studies which might further elucidate and strengthen the role of the stilbene family of compounds in cardiovascular disease and cardioprotection. Model systems that incorporate a significant functional association with tissues outside of the cardiovascular system proper, such as adipose (cell culture, obesity models) and pancreatic (diabetes) tissues, were reviewed, and the molecular pathways and/or targets related to these models and influenced by resveratrol are discussed. Because the body of work encompassing the stilbenes and other phytochemicals in the context of longevity and the ability to presumably mitigate a plethora of afflictions is replete with conflicting information and controversy, especially so with respect to the human response, we tried to remain as neutral as possible in compiling and presenting the more current data with minimal commentary, permitting the reader free reign to extract the knowledge most helpful to their own investigations.

Is Alzheimer's disease related to metabolic syndrome? A Wnt signaling conundrum

Alzheimer's disease (AD) is the most common cause of dementia, affecting more than 36 million people worldwide. AD is characterized by a progressive loss of cognitive functions. For years, it has been thought that age is the main risk factor for AD. Recent studies suggest that life style factors, including nutritional behaviors, play a critical role in the onset of dementia. Evidence about the relationship between nutritional behavior and AD includes the role of conditions such as obesity, hypertension, dyslipidemia and elevated glucose levels. The coexistence of some of these cardio-metabolic risk factors is generally known as metabolic syndrome (MS). Some clinical studies support the role of MS in the onset of AD. However, the cross-talk between the molecular signaling implicated in these disorders is unknown. In the present review, we focus on the molecular correlates that support the relationship between MS and the onset of AD. We also discuss relevant issues such as the role of leptin, insulin and renin-angiotensin signaling in the brain and the possible role of Wnt signaling in both MS and AD. We discuss the evidence supporting the use of ob/ob mice, high-fructose diets, aortic coarctation-induced hypertension and Octodon degus, which spontaneously develops β-amyloid deposits and metabolic derangements, as suitable animal models to address the relationships between MS and AD. Finally, we examine emergent data supporting the role of Wnt signaling in the modulation of AD and MS, implicating this pathway as a therapeutic target in both conditions.

Advanced glycation end-products: a common pathway in diabetes and age-related erectile dysfunction

Reactive derivatives of non-enzymatic glucose-protein condensation reactions integrate a heterogeneous group of irreversible adducts called advanced glycation end-products (AGEs). Numerous studies have investigated the role of the AGEs in cardiovascular system; however, its contribution to erectile dysfunction (ED) that is an early manifestation of cardiovascular disease has been less intensively investigated. This review summarizes the most recent advances concerning AGEs effects in the cavernous tissue of the penis and in ED onset, particularly on diabetes and aging, conditions that not only favor AGEs formation, but also increase risk of developing ED. The specific contribution of AGE on intra- and extracellular deposition of insoluble complexes, interference in activity of endothelial nitric oxide (NO) synthase, NO bioavailability, endothelial-dependent vasodilatation, as well as molecular pathways activated by receptor of AGEs are presented. Finally, the interventional actions that prevent AGEs formation, accumulation or activity in the cavernous tissue and that include nutritional pattern modulation, nutraceuticals, exercise, therapeutic strategies (statins, anti-diabetics, inhibitors of phosphodiesterase-5, anti-hypertensive drugs) and inhibitors of AGEs formation and crosslink breakers, are discussed. From this review, we conclude that despite the experiments conducted in animal models pointing to the AGE/RAGE axis as a potential interventional target with respect to ED associated with diabetes and aging, the clinical data have been very disappointing and, until now, did not provide evidence of benefits of treatments directed to AGE inactivation.

AGEs, contributors to placental bed vascular changes leading to preeclampsia

Glycation of proteins or other biomolecules and their further long-term degradation result in the formation of advanced glycation end products, AGEs. AGEs and other ligands interact with their receptors, RAGEs, localized to a variety of tissues, but mainly in endothelium and vascular wall cells. This interaction triggers diverse signaling pathways that converge on the activation of NF-κB and the initiation of a local inflammatory reaction that, when prolonged, results in dysfunctional features. Preeclampsia is a serious vascular disorder centred at the placenta-uterine interface, the placental bed, but the condition extends to the mother's circulation. RAGEs have notorious expression in the placental bed tissues along pregnancy but, in addition, RAGEs and their ligands are expressed in the fetal membranes and are found in the amniotic fluid and the mother's serum. Disorders complicating pregnancies and having an important vascular involvement, as preeclampsia and diabetes mellitus, have additional enhanced AGE/RAGE expression variation. This indicates that for their assessment, the assay of RAGEs or their ligands may become useful diagnostic or prognostic procedures.

Molecular strategies to prevent, inhibit, and degrade advanced glycoxidation and advanced lipoxidation end products

The advanced glycoxidation end products (AGEs) and lipoxidation end products (ALEs) contribute to the development of diabetic complications and of other pathologies. The review discusses the possibilities of counteracting the formation and stimulating the degradation of these species by pharmaceuticals and natural compounds. The review discusses inhibitors of ALE and AGE formation, cross-link breakers, ALE/AGE elimination by enzymes and proteolytic systems, receptors for advanced glycation end products (RAGEs) and blockade of the ligand-RAGE axis.