Of the renin-angiotensin system and reactive oxygen speciesType 2 diabetes and angiotensin II inhibition
Bibliographic record
Abstract
Rates of type 2 diabetes mellitus are increasing worldwide at an explosive rate. This "epidemic" is largely driven by a concomitant obesity epidemic, which is seen not only in affluent countries, but in industrializing countries as well, concomitant with the rapid change toward Western life-style patterns worldwide. Recent clinical trials such as Heart Outcomes Prevention Evaluation (HOPE), Losartan Intervention for Endpoint reduction (LIFE), and Study of Cognition and Prognosis in the Elderly (SCOPE) have indicated that blocking the renin-angiotensin system (RAS) may reduce the risk of developing type 2 diabetes mellitus. This effect may be explained by a variety of diabetogenic factors, which seem to be moderated by angiotensin II, such as free fatty acids (FFA) and the phenomena of adipocyte differentiation, as well as inflammation and oxidative damage. Insulin resistance, usually present in cases of impaired glucose tolerance, is the major identifiable defect in subjects at risk for type 2 diabetes. Elevated FFA levels result in reduced activation of phosphoinositol-3 kinase, an enzyme that is essential for normal insulin-stimulated glucose uptake. This reduction is potentiated by angiotensin II and consequently insulin-stimulated glucose uptake is improved by RAS inhibition. Furthermore, blockade of the angiotensin II AT(1)-receptor has been shown to stimulate the differentiation of adipocytes that store FFAs, which leads to reduced plasma FFA levels and decreased insulin resistance. There are also data suggesting that AT(1)-receptor blockade reduces inflammatory activation and the production of reactive oxygen species (ROS), a major factor in the pathophysiology of diabetes and a major cardiovascular risk factor. Both proinflammatory molecules and ROS increase the risk of insulin resistance and atherogenesis. It is thought that FFAs and hyperglycemia increase ROS production and oxidative stress, leading to the activation of signaling molecules such as nuclear factor kappa-B and other mediators of stress-sensitive pathways, which increases insulin resistance and will lead to beta-cell dysfunction and diabetic complications during the longer term. Inhibiting the RAS seems to have an effect on several steps in this cascade. There is an obvious need for large-scale clinical trials specifically designed to assess the protective benefits of blocking the RAS in individuals at risk of developing type 2 diabetes. Two such trials on the prevention of type 2 diabetes are ongoing, the Diabetes Reduction Assessment with Ramipril and Rosiglitazone Medications (DREAM) study and the more ambitious Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) trial, which is also assessing prevention of cardiovascular events.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".