The ratio of AGE to sRAGE independently associated with albuminuria in hypertensive patients

Disproportionately higher cardiovascular disease risk and incidence with high fructose corn syrup sweetened beverage intake among black young adults-the CARDIA study

BACKGROUND

The black/white heart disease mortality disparity began increasing in the early 1980's, coincident with the switch from sucrose to high-fructose-corn-syrup/(HFCS) in the US food supply. There has been more fructose in HFCS than generally-recognized-as-safe/GRAS, which has contributed to unprecedented excess-free-fructose/(unpaired-fructose) in foods/beverages. Average- per-capita excess-free-fructose, from HFCS, began exceeding dosages/(5-10 g) that trigger fructose-malabsorption in the early 1980's. Fructose malabsorption contributes to gut-dysbiosis and gut-in-situ-fructosylation of dietary peptides/incretins/(GLP-1/GIP) which forms atherosclerotic advanced-glycation-end-products. Both dysregulate gut endocrine function and are risk factors for cardiovascular disease/(CVD). Limited research shows that African Americans have higher fructose malabsorption prevalence than others. CVD risk begins early in life.

METHODS

Coronary-Artery-Risk-Development-in-Adults/(CARDIA) study data beginning in 1985-86 with 2186 Black and 2277 White participants, aged 18-30 y, were used to test the hypothesis that HFCS sweetened beverage intake increases CVD risk/incidence, more among Black than White young adults, and at lower intakes; while orange juice-a low excess-free-fructose juice with comparable total sugars and total fructose, but a 1:1 fructose-to-glucose-ratio, i.e., low excess-free-fructose, does not. Cox proportional hazards models were used to calculate hazard ratios.

RESULTS

HFCS sweetened beverage intake was associated with higher CVD risk (HR = 1.7) than smoking (HR = 1.6). CVD risk was higher at lower HFCS sweetened beverage intake among Black than White participants. Intake, as low as 3 times/wk, was associated with twice the CVD risk vs. less frequent/never, among Black participants only (HR 2.1, 95% CI 1.2-3.7; P = 0.013). Probability of an ordered relationship approached significance. Among Black participants, CVD incidence jumped 62% from 59.8/1000, among ≤ 2-times/wk, to 96.9/1000 among 3-6 times/wk consumers. Among White participants, CVD incidence increased from 37.6/1000, among ≤ 1.5-times/wk, to 41.1/1000, among 2 times/wk-once/d - a 9% increase. Hypertension was highest among Black daily HFCS sweetened beverage consumers.

CONCLUSION

The ubiquitous presence of HFCS over-the-past-40 years, at higher fructose-to-glucose ratios than generally-recognized-as-safe, may have contributed to CVD racial disparities, due to higher fructose-malabsorption prevalence among Black individuals, unpaired/excess-free-fructose induced gut dysbiosis and gut fructosylation of dietary peptides/incretins (GLP-1/GIP). These disturbances contribute to atherosclerotic plaque; promote incretin insufficiency/dysregulation/altered satiety/dysglycemia; decrease protective microbiota metabolites; and increase hypertension, CVD morbidity and mortality.

The RAGE/DIAPH1 axis: mediator of obesity and proposed biomarker of human cardiometabolic disease

Overweight and obesity are leading causes of cardiometabolic dysfunction. Despite extensive investigation, the mechanisms mediating the increase in these conditions are yet to be fully understood. Beyond the endogenous formation of advanced glycation endproducts (AGEs) in overweight and obesity, exogenous sources of AGEs accrue through the heating, production, and consumption of highly processed foods. Evidence from cellular and mouse model systems indicates that the interaction of AGEs with their central cell surface receptor for AGE (RAGE) in adipocytes suppresses energy expenditure and that AGE/RAGE contributes to increased adipose inflammation and processes linked to insulin resistance. In human subjects, the circulating soluble forms of RAGE, which are mutable, may serve as biomarkers of obesity and weight loss. Antagonists of RAGE signalling, through blockade of the interaction of the RAGE cytoplasmic domain with the formin, Diaphanous-1 (DIAPH1), target aberrant RAGE activities in metabolic tissues. This review focuses on the potential roles for AGEs and other RAGE ligands and RAGE/DIAPH1 in the pathogenesis of overweight and obesity and their metabolic consequences.

Involvement of AGE and Its Receptors in the Pathogenesis of Hypertension in Elderly People and Its Treatment

Both systolic and diastolic blood pressures increase with age up to 50 to 60 years of age. After 60 years of age systolic pressure rises to 84 years of age but diastolic pressure remains stable or even decreases. In the oldest age group (85-99 years), the systolic blood pressure (SBP) is high and diastolic pressure (DBP) is the lowest. Seventy percent of people older than 65 years are hypertensive. This paper deals with the role of advanced glycation end products (AGE) and its cell receptor (RAGE) and soluble receptor (sRAGE) in the development of hypertension in the elderly population. Plasma/serum levels of AGE are higher in older people as compared with younger people. Serum levels of AGE are positively correlated with age, arterial stiffness, and hypertension. Low serum levels of sRAGE are associated with arterial stiffness and hypertension. Levels of sRAGE are negatively correlated with age and blood pressure. Levels of sRAGE are lower in patients with arterial stiffness and hypertension than patients with high levels of sRAGE. AGE could induce hypertension through numerous mechanisms including, cross-linking with collagen, reduction of nitric oxide, increased expression of endothelin-1, and transforming growth factor-β (TGF-β). Interaction of AGE with RAGE could produce hypertension through the generation of reactive oxygen species, increased sympathetic activity, activation of nuclear factor-kB, and increased expression of cytokines, cell adhesion molecules, and TGF- β. In conclusion, the AGE-RAGE axis could be involved in hypertension in elderly people. Treatment for hypertension in elderly people should be targeted at reduction of AGE levels in the body, prevention of AGE formation, degradation of AGE in vivo, downregulation of RAGE expression, blockade of AGE-RAGE interaction, upregulation of sRAGE expression, and use of antioxidants.

INCREASED DIETARY INTAKE AND SERUM LEVELS OF ADVANCED GLYCATION END PRODUCTS (AGES) ARE ASSOCIATED WITH DIABETIC MACULAR EDEMA

Aim

Diabetic macular oedema (DME) can develop at all stages of diabetic retinopathy, causing visual impairment and blindness. Modern diets are high in advanced glycation end products (dAGEs), derived from processing methods, exerting a pivotal role in promoting diabetic retinopathy risk. In present study, we investigate the relationship between dietary and serum levels of AGEs and DME in type 2 diabetic subjects.

Methods

This case-control study was conducted between July 2018 and February 2019 on 50 case subjects with DME and 40 healthy controls without DM without DME. The sociodemographic characteristics, nutritional status, and anthropometric measurements were evaluated. The advanced glycation end products (AGEs) and receptor for AGEs (sRAGE) levels in serum were analysed.

Results

The AGEs levels of the DME group were higher than in the control group (p <0.05). sRAGE levels were higher in the DME group, but not statistically significant (p >0.05). The dietary intake of AGEs was higher in the DME group (p <0.05). It was found that an increase in neck circumference increased the risk of DME (p <0.001).

Conclusion

A positive correlation was found between DME and AGEs, dAGE, neck circumference, and waist circumference. For the validity of these results, studies, including controlled nutrition interventions, are needed.

The role of soluble receptor for advanced glycation end-products (sRAGE) in the general population and patients with diabetes mellitus with a focus on renal function and overall outcome

Isoforms of the receptor for advanced glycation end-product (RAGE) protein, which lack the transmembrane and the signaling (soluble RAGE or sRAGE) domains are hypothesized to counteract the detrimental action of the full-length receptor by acting as a decoy, and they provide a potential tool to treat RAGE-associated diseases. Multiple studies have explored the relationship between sRAGE and endogenous secretory RAGE and its polymorphism and obesity, metabolic syndrome, atherosclerosis, kidney function, and increased mortality in the general population. In addition, sRAGE may be a key player in the pathogenesis of diabetes mellitus and its microvascular (e.g. kidney disease) as well as macrovascular (e.g. cardiovascular disease) complications. In this review, we focus on the role of sRAGE as a biomarker in these specific areas. As there is a lack of an underlying unifying hypothesis about how sRAGE changes according to the disease condition or risk factor, there is a call to incorporate all three players of the AGE-RAGE axis into a new universal biomarker/risk marker: (AGE + RAGE)/sRAGE. However, the measurement of RAGE in humans is not practical as it is a cell-bound receptor for which tissue is required for analysis. A high AGE/sRAGE ratio may be a valuable alternative and practical universal biomarker/risk marker for diseases associated with the AGE-RAGE axis, irrespective of low or high serum sRAGE concentrations.