In parallel with the growing diabetes pandemic, there is an increasing burden of micro- and macrovascular complications, occurring in the majority of patients. The identification of a number of ...synergistic accelerators of disease, providing therapeutic pathways, has stabilised the incidence of complications in most western nations. However, the primary instigators of diabetic complications and, thus, prevention strategies, remain elusive. This has necessitated a refocus on natural history studies, where tissue and plasma samples are sequentially taken to determine when and how disease initiates. In addition, recent Phase III trials, wherein the pleiotropic effects of compounds were arguably as beneficial as their glucose-lowering capacity in slowing the progression of complications, have identified knowledge gaps. Recently the influence of other widely recognised pathological pathways, such as mitochondrial production of reactive oxygen species, has been challenged, highlighting the need for a diverse and robust global research effort to ascertain viable therapeutic targets. Technological advances, such as -omics, high-resolution imaging and computational modelling, are providing opportunities for strengthening and re-evaluating research findings. Newer areas such as epigenetics, energetics and the increasing scrutiny of our synergistic inhabitants, the microbiota, also offer novel targets as biomarkers. Ultimately, however, this field requires concerted lobbying to support all facets of diabetes research.
Since the 1980s, chronic kidney disease (CKD) affecting all ages has increased by almost 25%. This increase may be partially attributable to lifestyle changes and increased global consumption of a ...“western” diet, which is typically energy dense, low in fruits and vegetables, and high in animal protein and ultra-processed foods. These modern food trends have led to an increase in the consumption of advanced glycation end products (AGEs) in conjunction with increased metabolic dysfunction, obesity and diabetes, which facilitates production of endogenous AGEs within the body. When in excess, AGEs can be pathological via both receptor-mediated and non-receptor-mediated pathways. The kidney, as a major site for AGE clearance, is particularly vulnerable to AGE-mediated damage and increases in circulating AGEs align with risk of CKD and all-cause mortality. Furthermore, individuals with significant loss of renal function show increased AGE burden, particularly with uraemia, and there is some evidence that AGE lowering via diet or pharmacological inhibition may be beneficial for CKD. This review discusses the pathways that drive AGE formation and regulation within the body. This includes AGE receptor interactions and pathways of AGE-mediated pathology with a focus on the contribution of diet on endogenous AGE production and dietary AGE consumption to these processes. We then analyse the contribution of AGEs to kidney disease, the evidence for dietary AGEs and endogenously produced AGEs in driving pathogenesis in diabetic and non-diabetic kidney disease and the potential for AGE targeted therapies in kidney disease.
Blood glucose control is the primary strategy to prevent complications in diabetes. At the onset of kidney disease, therapies that inhibit components of the renin angiotensin system (RAS) are also ...indicated, but these approaches are not wholly effective. Here, we show that once daily administration of the novel glucose lowering agent, empagliflozin, an SGLT2 inhibitor which targets the kidney to block glucose reabsorption, has the potential to improve kidney disease in type 2 diabetes. In male db/db mice, a 10-week treatment with empagliflozin attenuated the diabetes-induced upregulation of profibrotic gene markers, fibronectin and transforming-growth-factor-beta. Other molecular (collagen IV and connective tissue growth factor) and histological (tubulointerstitial total collagen and glomerular collagen IV accumulation) benefits were seen upon dual therapy with metformin. Albuminuria, urinary markers of tubule damage (kidney injury molecule-1, KIM-1 and neutrophil gelatinase-associated lipocalin, NGAL), kidney growth, and glomerulosclerosis, however, were not improved with empagliflozin or metformin, and plasma and intra-renal renin activity was enhanced with empagliflozin. In this model, blood glucose lowering with empagliflozin attenuated some molecular and histological markers of fibrosis but, as per treatment with metformin, did not provide complete renoprotection. Further research to refine the treatment regimen in type 2 diabetes and nephropathy is warranted.
Type 1 diabetes (T1D) is one of the most common chronic diseases manifesting in early life, with the prevalence increasing worldwide at a rate of approximately 3% per annum. The prolonged ...hyperglycaemia characteristic of T1D upregulates the receptor for advanced glycation end products (RAGE) and accelerates the formation of RAGE ligands, including advanced glycation end products, high‐mobility group protein B1, S100 calcium‐binding proteins, and amyloid‐beta. Interestingly, changes in the expression of RAGE and these ligands are evident in patients before the onset of T1D. RAGE signals via various proinflammatory cascades, resulting in the production of reactive oxygen species and cytokines. A large number of proinflammatory ligands that can signal via RAGE have been implicated in several chronic diseases, including T1D. Therefore, it is unsurprising that RAGE has become a potential therapeutic target for the treatment and prevention of disease. In this review, we will explore how RAGE might be targeted to prevent the development of T1D.
Highlights • Cardiovascular disease (CVD) has many risk factors contributing to development. • Advanced glycation endproducts (AGEs) contribute to many pathologies of CVD. • Mitochondrial dysfunction ...(mito-stress) facilitates pathological events. • Targeting of both AGEs and mito-stress may hold the key to CVD treatment.
Type 1 diabetes (T1D) is an autoimmune disease in which the β-cells of the pancreas are attacked by the host's immune system, ultimately resulting in hyperglycemia. It is a complex multifactorial ...disease postulated to result from a combination of genetic and environmental factors. In parallel with increasing prevalence of T1D in genetically stable populations, highlighting an environmental component, consumption of advanced glycation end products (AGEs) commonly found in in Western diets has increased significantly over the past decades. AGEs can bind to cell surface receptors including the receptor for advanced glycation end products (RAGE). RAGE has proinflammatory roles including in host-pathogen defense, thereby influencing immune cell behavior and can activate and cause proliferation of immune cells such as islet infiltrating CD8
and CD4
T cells and suppress the activity of T regulatory cells, contributing to β-cell injury and hyperglycemia. Insights from studies of individuals at risk of T1D have demonstrated that progression to symptomatic onset and diagnosis can vary, ranging from months to years, providing a window of opportunity for prevention strategies. Interaction between AGEs and RAGE is believed to be a major environmental risk factor for T1D and targeting the AGE-RAGE axis may act as a potential therapeutic strategy for T1D prevention.
There is a paucity of data on whether Australian university students are meeting specific nutrient guidelines, and the relationship between diet and physical activity patterns with body composition ...and metabolic health. In this study, biomedical students from The University of Queensland were recruited (150 males and 211 females, 19–25 years), and nutritional intake (ASA24-Australia) and physical activity levels (Active Australia Survey) quantified. Body composition (height, waist circumference, body mass, BMI, and percentage body fat; BOD POD) and metabolic health (oral glucose tolerance test) were also measured. Median daily energy intake was 6760 kJ in females and 10,338 kJ in males, with more than 30% of total energy coming from energy-dense, nutrient-poor foods. Only 1 in 10 students met fruit or vegetable recommendations, with less than one third meeting recommendations for fibre, calcium, and potassium. Intakes of calcium and iron were particularly low among female students, with only 16% and 6% of students meeting the recommended dietary intake (RDI), respectively. The majority of males and almost half of all females exceeded the suggested dietary target (SDT) for sodium. Sufficient physical activity (≥150 min over ≥5 sessions per week) was met by more than 80% of students. Body composition and blood glucose concentrations were largely normal but an early sign of insulin resistance (HOMA-IR > 2.0), measured in a subset of students, was present in 21% of males and 17% of females. Modest reductions in blood glucose levels and percentage body fat were associated with increasing vigorous activity. Low intakes of fibre, calcium, and potassium could be corrected by increasing fruit, vegetable, and dairy intake, and, among females, health promotion messages focusing on iron-rich foods should be prioritised. While these nutrient deficiencies did not translate into immediate metabolic heath concerns, dietary behaviours can track into adulthood and have lasting effects on overall health.
To examine if skin autofluorescence (sAF) differed in early adulthood between individuals with type 1 diabetes and age-matched controls and to ascertain if sAF aligned with risk for kidney disease. ...Young adults with type 1 diabetes (N = 100; 20.0 ± 2.8 years; M:F 54:46; FBG-11.6 ± 4.9 mmol/mol; diabetes duration 10.7 ± 5.2 years; BMI 24.5(5.3) kg/m
) and healthy controls (N = 299; 20.3 ± 1.8 years; M:F-83:116; FBG 5.2 ± 0.8 mmol/L; BMI 22.5(3.3) kg/m
) were recruited. Skin autofluorescence (sAF) and circulating AGEs were measured. In a subset of both groups, kidney function was estimated by GFR
and uACR, and DKD risk defined by uACR tertiles. Youth with type 1 diabetes had higher sAF and BMI, and were taller than controls. For sAF, 13.6% of variance was explained by diabetes duration, height and BMI (P
= 1.5 × 10
). In the sub-set examining kidney function, eGFR and sAF were higher in type 1 diabetes versus controls. eGFR and sAF predicted 24.5% of variance in DKD risk (P
= 2.2 × 10
), which increased with diabetes duration (51%; P
< 2.2 × 10
) and random blood glucose concentrations (56%; P
< 2.2 × 10
). HbA
and circulating fructosamine albumin were higher in individuals with type 1 diabetes at high versus low DKD risk. eGFR was independently associated with DKD risk in all models. Higher eGFR and longer diabetes duration are associated with DKD risk in youth with type 1 diabetes. sAF, circulating AGEs, and urinary AGEs were not independent predictors of DKD risk. Changes in eGFR should be monitored early, in addition to uACR, for determining DKD risk in type 1 diabetes.
Type 1 diabetes is an autoimmune disease with no cure, where clinical translation of promising therapeutics has been hampered by the reproducibility crisis. Here, short-term administration of an ...antagonist to the receptor for advanced glycation end products (sRAGE) protected against murine diabetes at two independent research centers. Treatment with sRAGE increased regulatory T cells (Tregs) within the islets, pancreatic lymph nodes, and spleen, increasing islet insulin expression and function. Diabetes protection was abrogated by Treg depletion and shown to be dependent on antagonizing RAGE with use of knockout mice. Human Tregs treated with a RAGE ligand downregulated genes for suppression, migration, and Treg homeostasis (FOXP3, IL7R, TIGIT, JAK1, STAT3, STAT5b, CCR4). Loss of suppressive function was reversed by sRAGE, where Tregs increased proliferation and suppressed conventional T-cell division, confirming that sRAGE expands functional human Tregs. These results highlight sRAGE as an attractive treatment to prevent diabetes, showing efficacy and reproducibility at multiple research centers and in human T cells.
Postprandial glucose excursions are postulated to increase the risk for diabetes complications via the production of advanced glycation end products (AGEs). The soluble receptor of AGEs (sRAGE) ...likely acts as a decoy receptor, mopping up AGEs, diminishing their capacity for pro-inflammatory and pro-apoptotic signaling. Recent evidence suggests that AGEs and soluble receptor for AGEs (sRAGE) may be altered under postprandial and fasting conditions. Here, we investigated the effects of increasing oral glucose loads during oral glucose tolerance tests (OGTT) and matched isoglycaemic intravenous (i.v.) glucose infusions (IIGI) on circulating concentrations of sRAGE. Samples from eight individuals with type 2 diabetes and eight age-, gender-, and body mass index (BMI)-matched controls, all of whom underwent three differently dosed OGTTs (25 g, 75 g, and 125 g), and three matched IIGIs were utilised (NCT00529048). Serum concentrations of sRAGE were measured over 240 min during each test. For individuals with diabetes, sRAGE area under the curve (AUC
) declined with increasing i.v. glucose dosages (
< 0.0001 for trend) and was lower during IIGI compared to OGTT at the 125 g dosage (
= 0.004). In control subjects, sRAGE AUC
was only lower during IIGI compared to OGTT at the 25 g dose (
= 0.0015). sRAGE AUC
was negatively correlated to AUC
for the incretin hormone glucagon-like peptide -1 (GLP-1) during the 75 g OGTT and matched IIGI, but only in individuals with type 2 diabetes. These data suggest that gastrointestinal factors may play a role in regulating sRAGE concentrations during postprandial glucose excursions, thus warranting further investigation.
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