Summary Glucose metabolism is normally regulated by a feedback loop including islet β cells and insulin-sensitive tissues, in which tissue sensitivity to insulin affects magnitude of β-cell response. ...If insulin resistance is present, β cells maintain normal glucose tolerance by increasing insulin output. Only when β cells cannot release sufficient insulin in the presence of insulin resistance do glucose concentrations rise. Although β-cell dysfunction has a clear genetic component, environmental changes play an essential part. Modern research approaches have helped to establish the important role that hexoses, aminoacids, and fatty acids have in insulin resistance and β-cell dysfunction, and the potential role of changes in the microbiome. Several new approaches for treatment have been developed, but more effective therapies to slow progressive loss of β-cell function are needed. Recent findings from clinical trials provide important information about methods to prevent and treat type 2 diabetes and some of the adverse effects of these interventions. However, additional long-term studies of drugs and bariatric surgery are needed to identify new ways to prevent and treat type 2 diabetes and thereby reduce the harmful effects of this disease.
It is increasingly apparent that not only is a cure for the current worldwide diabetes epidemic required, but also for its major complications, affecting both small and large blood vessels. These ...complications occur in the majority of individuals with both type 1 and type 2 diabetes. Among the most prevalent microvascular complications are kidney disease, blindness, and amputations, with current therapies only slowing disease progression. Impaired kidney function, exhibited as a reduced glomerular filtration rate, is also a major risk factor for macrovascular complications, such as heart attacks and strokes. There have been a large number of new therapies tested in clinical trials for diabetic complications, with, in general, rather disappointing results. Indeed, it remains to be fully defined as to which pathways in diabetic complications are essentially protective rather than pathological, in terms of their effects on the underlying disease process. Furthermore, seemingly independent pathways are also showing significant interactions with each other to exacerbate pathology. Interestingly, some of these pathways may not only play key roles in complications but also in the development of diabetes per se. This review aims to comprehensively discuss the well validated, as well as putative mechanisms involved in the development of diabetic complications. In addition, new fields of research, which warrant further investigation as potential therapeutic targets of the future, will be highlighted.
Chronic kidney disease (CKD) is a common comorbidity in patients with type 2 diabetes mellitus (T2DM) and both conditions are increasing in prevalence. CKD is estimated to affect ∼50% patients with ...T2DM globally, and its presence and severity markedly influences disease prognosis. CKD is more common in certain patient populations, including the elderly, those with youth-onset diabetes mellitus, those who are obese, certain ethnic groups, and disadvantaged populations. These same settings have also seen the greatest increase in the prevalence of T2DM, as exemplified by the increasing prevalence of T2DM in low-to- middle income countries. Patients from low-to-middle income countries are often the least able to deal with the burden of T2DM and CKD and the health-care facilities of these countries least able to deal with the demand for equitable access to renal replacement therapies. The increasing prevalence of younger individuals with T2DM, in whom an accelerated course of complications can be observed, further adds to the global burden of CKD. Paradoxically, improvements in cardiovascular survival in patients with T2DM have contributed to patients surviving longer, allowing sufficient time to develop renal impairment. This Review explores how the changing epidemiology of T2DM has influenced the prevalence and incidence of associated CKD across different populations and clinical settings.
The cytokine transforming growth factor (TGF)-β1 plays a central role in diabetic nephropathy (DN) with data implicating the miRNA (miR) miR-21 as a key modulator of its prosclerotic actions. In the ...present study, we demonstrate data indicating that miR-21 up-regulation positively correlates with the severity of fibrosis and rate of decline in renal function in human DN. Furthermore, concomitant analyses of various models of fibrotic renal disease and experimental DN, confirm tubular miR-21 up-regulation. The fibrotic changes associated with increased miR-21 levels are proposed to include the regulation of TGF-β1-mediated mothers against decapentaplegic homolog 3 (SMAD3)- and phosphoinositide 3-kinase (PI3K)-dependent signalling pathways via co-ordinated repression of mothers against decapentaplegic homolog 7 (SMAD7) and phosphatase and tensin homologue (PTEN) respectively. This represents a previously uncharacterized interaction axis between miR-21 and PTEN-SMAD7. Targeting of these proteins by miR-21 resulted in de-repression of the respective pathways as reflected by increases in SMAD3 and V-Akt murine thymoma viral oncogene homolog 1 (AKT) phosphorylation. Many of the changes typically induced by TGF-β1, including phosphorylation of signalling mediators, were further enhanced by miR-21. Collectively, these data present a unified model for a key role for miR-21 in the regulation of renal tubular extracellular matrix (ECM) synthesis and accumulation and provide important insights into the molecular pathways implicated in the progression of DN.
It is postulated that localized tissue oxidative stress is a key component in the development of diabetic nephropathy. There remains controversy, however, as to whether this is an early link between ...hyperglycemia and renal disease or develops as a consequence of other primary pathogenic mechanisms. In the kidney, a number of pathways that generate reactive oxygen species (ROS) such as glycolysis, specific defects in the polyol pathway, uncoupling of nitric oxide synthase, xanthine oxidase, NAD(P)H oxidase, and advanced glycation have been identified as potentially major contributors to the pathogenesis of diabetic kidney disease. In addition, a unifying hypothesis has been proposed whereby mitochondrial production of ROS in response to chronic hyperglycemia may be the key initiator for each of these pathogenic pathways. This postulate emphasizes the importance of mitochondrial dysfunction in the progression and development of diabetes complications including nephropathy. A mystery remains, however, as to why antioxidants per se have demonstrated minimal renoprotection in humans despite positive preclinical research findings. It is likely that the utility of current study approaches, such as vitamin use, may not be the ideal antioxidant strategy in human diabetic nephropathy. There is now an increasing body of data to suggest that strategies involving a more targeted antioxidant approach, using agents that penetrate specific cellular compartments, may be the elusive additive therapy required to further optimize renoprotection in diabetes.
Context: Diabetic complications appear to be multifactorial in origin, but in particular, the biochemical process of advanced glycation, which is accelerated in diabetes as a result of chronic ...hyperglycemia and increased oxidative stress, has been postulated to play a central role in these disorders. Advanced glycation involves the generation of a heterogenous group of chemical moieties known as advanced glycated end products (AGEs), this reaction occurring as a result of a nonenzymatic reaction with glucose interacting with proteins, lipids, and nucleic acids, and involves key intermediates such as methylglyoxal.
Evidence Synthesis: In this review we report on how these AGEs may exert deleterious effects in diabetes, as well as address current strategies to interrupt the formation or action of AGEs. First, AGEs act directly to induce cross-linking of long-lived proteins such as collagen to promote vascular stiffness, and, thus, alter vascular structure and function. Second, AGEs can interact with certain receptors, such as the receptor for AGE, to induce intracellular signaling that leads to enhanced oxidative stress and elaboration of key proinflammatory and prosclerotic cytokines. Over the last decade, a large number of preclinical studies have been performed, targeting the formation and degradation of AGEs, as well as the interaction of these AGEs with receptors such as the receptor for AGE.
Conclusion: It is hoped that over the next few years, some of these promising therapies will be fully evaluated in the clinical context with the ultimate aim to reduce the major economical and medical burden of diabetes, its vascular complications.
Obesity, diabetes mellitus, hypertension and cardiovascular disease are risk factors for chronic kidney disease (CKD) and kidney failure. Chronic, low-grade inflammation is recognized as a major ...pathogenic mechanism that underlies the association between CKD and obesity, impaired glucose tolerance, insulin resistance and diabetes, through interaction between resident and/or circulating immune cells with parenchymal cells. Thus, considerable interest exists in approaches that target inflammation as a strategy to manage CKD. The initial phase of the inflammatory response to injury or metabolic dysfunction reflects the release of pro-inflammatory mediators including peptides, lipids and cytokines, and the recruitment of leukocytes. In self-limiting inflammation, the evolving inflammatory response is coupled to distinct processes that promote the resolution of inflammation and restore homeostasis. The discovery of endogenously generated lipid mediators - specialized pro-resolving lipid mediators and branched fatty acid esters of hydroxy fatty acids - which promote the resolution of inflammation and attenuate the microvascular and macrovascular complications of obesity and diabetes mellitus highlights novel opportunities for potential therapeutic intervention through the targeting of pro-resolution, rather than anti-inflammatory pathways.
Aims/hypothesis
Data are inconsistent regarding the associations between age, age at diagnosis of diabetes, diabetes duration and subsequent vascular complications.
Methods
The associations between ...age (or age at diagnosis), diabetes duration and major macrovascular events, all-cause death and major microvascular events were examined in 11,140 patients with type 2 diabetes randomly allocated to intensive or standard glucose control in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial. Rates were calculated by 5 year baseline age (or age at diagnosis) and diabetes duration strata. Risks were estimated using Cox models adjusted for treatment assignment and HbA
1c
.
Results
The mean age (±SD) was 65.8 ± 6.4 years, age at diagnosis was 57.8 ± 8.7 years and diabetes duration was 7.9 ± 6.4 years. Diabetes duration was associated with the risk of macrovascular events (HR 1.13 95% CI 1.08, 1.17), microvascular events (1.28 1.23, 1.33) and death (1.15 1.10, 1.20) whereas age (or age at diagnosis) was only associated with the risk of macrovascular events (1.33 1.27, 1.39) and death (1.56 1.48, 1.64). No interaction was observed between diabetes duration, age and the risk of macrovascular events or death (both
p
> 0.4). However, an interaction was observed between diabetes duration, age and the risk of microvascular events (
p
= 0.002), such that the effects of increasing diabetes duration were greatest at younger rather than older age.
Conclusions/interpretation
In patients with type 2 diabetes, age or age at diagnosis and diabetes duration are independently associated with macrovascular events and death whereas only diabetes duration is independently associated with microvascular events and this effect is greater in the youngest patients.
New-Onset Diabetes in Covid-19 Rubino, Francesco; Amiel, Stephanie A; Zimmet, Paul ...
New England journal of medicine/The New England journal of medicine,
08/2020, Letnik:
383, Številka:
8
Journal Article
YB-1: the Jekyll and Hyde of kidney disease? Kantharidis, Phillip; Cooper, Mark E.
Kidney international,
January 2024, 2024-Jan, 2024-01-00, 20240101, Letnik:
105, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Y-box–binding protein 1 is a well-described and important regulator of gene transcription, which is linked to various pathologic conditions, including inflammation and fibrosis of the kidney. The ...identification of a novel and protective crosstalk pathway between podocytes and tubular cells in the kidney with Y-box–binding protein 1 acting as a paracrine messenger sheds new light and provides novel opportunities for renoprotection.
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