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Query: UMLS:C0011860 (
type 2 diabetes
)
57,723
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Endothelial dysfunction is associated with hypertension, hypercholesterolemia, and heart failure. We tested the hypothesis that spontaneously diabetic Goto-Kakizaki (GK) rats, a model for
type 2 diabetes
, exhibit endothelial dysfunction. Rats also received a high-sodium diet (6% NaCl [wt/wt]) and chronic angiotensin type 1 (AT(1)) receptor blockade (10 mg/kg PO valsartan for 8 weeks). Compared with age-matched nondiabetic Wistar control rats, GK rats had higher blood glucose levels (9.3+/-0.5 versus 6.9+/-0.2 mmol/L for control rats), 2.7-fold higher serum insulin levels, and impaired glucose tolerance (all P<0.05). Telemetry-measured mean blood pressure was 15 mm Hg higher in GK rats (P<0.01) compared with control rats, whereas heart rates were not different. Heart weight- and kidney weight-to-body weight ratios were higher in GK rats (P<0.05), and 24-hour albuminuria was increased 50%. Endothelium-mediated relaxation of noradrenaline-precontracted mesenteric arterial rings by acetylcholine was impaired compared with the control condition (P<0.05), whereas the sodium nitroprusside-induced relaxation was similar. Preincubation of the arterial rings with the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester and the cyclooxygenase inhibitor diclofenac inhibited relaxations to acetylcholine almost completely in GK rats but not in Wistar rats, suggesting that endothelial dysfunction can be in part attributed to reduced relaxation via arterial K(+) channels. Perivascular monocyte/macrophage infiltration and intercellular adhesion molecule-1 overexpression were observed in GK rat kidneys. A high-sodium diet increased blood pressure by 24 mm Hg and 24-hour albuminuria by 350%, induced cardiac hypertrophy, impaired endothelium-dependent relaxation further, and aggravated inflammation (all P<0.05). The serum level of 8-isoprostaglandin F(2alpha), a vasoconstrictor and antinatriuretic arachidonic acid metabolite produced by oxidative stress, was increased 400% in GK rats on a high-sodium diet.
Valsartan
decreased blood pressure in rats fed a low-sodium diet and prevented the inflammatory response. In rats fed a high-sodium diet, valsartan did not decrease blood pressure or improve endothelial dysfunction but protected against albuminuria, inflammation, and oxidative stress. As measured by quantitative autoradiography, AT(1) receptor expression in the medulla was decreased in GK compared with Wistar rats, whereas cortical AT(1) receptor expression, medullary and cortical angiotensin type 2 (AT(2)) receptor expressions, and adrenal ACE and neutral endopeptidase expressions were unchanged. A high-sodium diet did not influence renal AT(1), AT(2), ACE, or neutral endopeptidase expressions. In valsartan-treated GK rats, the cortical and medullary AT(1) receptor expressions were decreased in the presence and absence of a high-sodium diet. A high-sodium diet increased plasma brain natriuretic peptide concentrations in presence and absence of valsartan treatment. We conclude that hypertension in GK rats is salt sensitive and associated with endothelial dysfunction and perivascular inflammation. AT(1) receptor blockade ameliorates inflammation during a low-sodium diet and partially protects against salt-induced vascular damage by blood pressure-independent mechanisms.
...
PMID:Endothelial dysfunction and salt-sensitive hypertension in spontaneously diabetic Goto-Kakizaki rats. 1123 Mar 14
Blood pressure reduction is the most significant factor in delaying onset and progression of renal disease. Blockade of the renin-angiotensin system (RAS) using angiotensin-converting enzyme inhibitors (ACEIs) delays renal disease progression. More recently, agents that block the RAS by preventing angiotensin II from binding to its subtype 1 receptor (ARBs) have been developed in an effort to prevent deleterious consequences of pathologic levels of angiotensin II and to reduce the adverse effects of RAS blockade associated with ACEIs. Human studies with a variety of ARBs have clearly demonstrated the antihypertensive and antiproteinuric efficacy of these agents in patients with progressive renal diseases. Moreover, the effects of ARBs are similar or identical to those of ACEIs. Ongoing long-term clinical trials are designed to determine whether ARBs also preserve renal function similar to ACEIs. Specifically, the role of ARBs in patients with hypertension and
type 2 diabetes
is being evaluated in 3 large trials, including Appropriate Blood Pressure Control in Diabetes-Part 2 With
Valsartan
, the Losartan Renal Protection Study, and the Irbesartan Diabetic Nephropathy Trial. Definitive evidence of the long-term protective effects of ARBs in chronic progressive renal disease is expected from these important studies.
...
PMID:Angiotensin II subtype 1 receptor blockers and renal function. 1142 96
Valsartan
is an orally active, selective antagonist of the angiotensin II-1 (AT1) receptor developed for the treatment of hypertension. The
Valsartan
Antihypertensive Long-term Use Evaluation (VALUE) Trial of Cardiovascular Events in Hypertension is a double-blind, randomized prospective, parallel group study designed to compare the effects of valsartan with those of the calcium-antagonist amlodipine on the reduction of cardiac morbidity and mortality. Patients with essential hypertension, aged 50 years and older, and at particularly high risk of coronary events were enrolled. 18,119 patients were screened and 15,314 patients in 31 countries were randomized mainly between January 1998 and December 1999. These hypertensives had a mean blood pressure of 154.7/87.5 mmHg at the time of their randomization to blinded medication. The population comprises both genders (men 57.6%), Caucasians (89.1%), mean age 67.2 years, mean body mass index 28.6 kg/m2, coronary heart disease (45.8%), high cholesterol (33.0%),
type 2 diabetes
mellitus (31.7%) and smokers (24.0%). More than 92% of the randomized participants had been treated for high blood pressure for at least 6 months when screened for the study. The randomized population is now being treated (goal blood pressure < 140/90 mmHg) in adherence with the protocol until at least 1450 patients experience primary cardiac endpoint defined as clinically evident or aborted myocardial infarction, hospitalization for heart failure or death caused by coronary heart disease.
...
PMID:Characteristics of 15,314 hypertensive patients at high coronary risk. The VALUE trial. The Valsartan Antihypertensive Long-term Use Evaluation. 1146 64
The Reduction in End Points in
NIDDM
with the Angiotensin II Antagonist Losartan (RENAAL) study and the Irbesartan Diabetic Nephropathy Trial (IDNT) are two recently reported trials with hard end points, conducted in patients in advanced stages of diabetic nephropathy. Two other studies--the Irbesartan Microalbuminuria Study (IRMA)-2 and the Microalbuminuria Reduction with
Valsartan
study (MARVAL)--were trials conducted in patients with
type 2 diabetes
with microalbuminuria, a cardiovascular risk factor associated with early-stage diabetic nephropathy. These trials all had a common theme--that is, does an angiotensin receptor blocker (ARB) interfere with the natural history of diabetic nephropathy in a blood pressure-independent fashion? Without question, the results of these trials legitimatize the use of the ARB class in forestalling the deterioration in renal function, which is almost inevitable in the patient with untreated diabetic nephropathy. These data can now be added to the vast array of evidence supporting angiotensin-converting enzyme (ACE) inhibitor use in patients with nephropathy associated with type 1 diabetes. It now appears a safe conclusion that the patient with diabetic nephropathy should receive therapy with an agent that interrupts the renin-angiotensin system. These studies have not resolved the question as to whether an ACE inhibitor or an ARB is the preferred agent in people with nephropathy from type 1 diabetes, though the optimal doses of these drugs remain to be determined. Head-to-head studies comparing ACE inhibitors to ARBs in diabetic nephropathy are not likely to occur, so it is unlikely that comparable information will be forthcoming with ACE inhibitors. An evidence-based therapeutic approach derived from these trials would argue for ARBs to be the foundation of therapy in the patient with
type 2 diabetes
and nephropathy.
...
PMID:Type 2 diabetes: RENAAL and IDNT--the emergence of new treatment options. 1182 41
In this article, 2 leading physicians debate the strength of outcome data on the efficacy of angiotensin-converting enzyme (ACE) inhibitors versus angiotensin II receptor blockers (ARBs) for reducing the incidence of cardiovascular, cerebrovascular, and renovascular events. Dr. Stephen G. Ball notes that the efficacy of ACE inhibitors for reducing the risk for myocardial infarction independent of their effects on blood pressure is controversial. In the Heart Outcomes Prevention Evaluation (HOPE) study, ramipril treatment in high-risk patients was associated with a 20% reduction in the risk for myocardial infarction; mean reduction in blood pressure was 3 mm Hg for systolic blood pressure and 1 mm Hg for diastolic blood pressure. The HOPE investigators propose that the 20% reduction was much greater than would be expected based on the observed blood pressure reduction. However, a meta-regression analysis of blood pressure reduction in >20 antihypertensive therapy outcome trials found that the reduction in myocardial infarction risk with ramipril observed in HOPE was consistent with the modest blood pressure reduction seen with that agent. Nevertheless, there are convincing data for prevention of myocardial infarction with ACE inhibitors in patients with heart failure, including those with heart failure after myocardial infarction, as well as supportive evidence from studies in patients with diabetes mellitus and concomitant hypertension. On the other hand, Dr. William B. White takes the position that ARBs are well-tolerated antihypertensive agents that specifically antagonize the angiotensin II type 1 (AT(1)) receptor and provide a more complete block of the pathologic effects of angiotensin II-which are mediated via the AT(1) receptor-than ACE inhibitors. The Evaluation of Losartan in the Elderly (ELITE) II study and the
Valsartan
Heart Failure Trial (ValHeFT) suggest that ARBs reduce the risk for mortality in patients with congestive heart failure. The Losartan Intervention for Endpoint (LIFE) Reduction in Hypertension trial also demonstrated beneficial effects of ARBs in the prevention of stroke events. The Irbesartan in Patients with Diabetes and Microalbuminuria (IRMA) study, the Irbesartan Diabetic Nephropathy Trial (IDNT), and the Reduction of Endpoints in
NIDDM
with the Angiotensin II Antagonist Losartan (RENAAL) study demonstrated significant reductions in the rate of progression of renal disease in patients receiving ARBs, independent of effects on blood pressure. These data support the use of ARBs, in addition to the standard of care, in hypertensive patients with heart failure who are intolerant of ACE inhibitors, and also provide compelling evidence for their use in patients with hypertension and
type 2 diabetes
.
...
PMID:Debate: angiotensin-converting enzyme inhibitors versus angiotensin II receptor blockers--a gap in evidence-based medicine. 1451 6
Burgeoning obesity is increasing the prevalence of
type II diabetes mellitus
. As a consequence, there will be an even greater burden of cardiovascular disease, end-stage renal disease, blindness, and lower extremity amputations. If diagnosed, impaired glucose tolerance presents an opportunity for intervention that potentially could delay or prevent the development of diabetes. Recent prospective studies document the effectiveness of exercise and weight reduction in preventing diabetes. Metformin is less effective than intense lifestyle interventions. Acarbose, losartan, orlistat, pravastatin, ramipril, and hormone replacement therapy are associated with lower rates of the development of diabetes. The Diabetes Reduction Assessment with Ramipril and Rosiglitazone Medication (DREAM) trial and the Nateglinide and
Valsartan
in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) trial were designed to assess not only the prevention of diabetes but also the impact on cardiovascular morbidity and mortality.
...
PMID:Preventing type II diabetes mellitus. 1505 49
Type 2 diabetes mellitus
is becoming a major health problem associated with excess morbidity and mortality. As the prevalence of
type 2 diabetes
is rapidly increasing, prevention of the disease should be considered as a key objective in the near future. Besides lifestyle changes, various pharmacological treatments have proven their efficacy in placebo-controlled clinical trials, including antidiabetic drugs such as metformin, acarbose and troglitazone, or antiobesity agents such as orlistat. Arterial hypertension, a clinical entity in which insulin resistance is common, is strongly associated with
type 2 diabetes
and may precede the disease by several years. While antihypertensive agents such as diuretics or beta-adrenoceptor antagonists may worsen insulin resistance and impair glucose tolerance, newer antihypertensive agents exert neutral or even slightly positive metabolic effects. Numerous clinical trials have investigated the effects of ACE inhibitors or angiotensin II receptor antagonists (ARAs) on insulin sensitivity in hypertensive patients, with or without diabetes, with no consistent results. Almost half of the studies with ACE inhibitors in hypertensive nondiabetic individuals demonstrated a slight but significant increase in insulin sensitivity as assessed by insulin-stimulated glucose disposal during a euglycaemic hyperinsulinaemic clamp, while the other half failed to reveal any significant change. The effects of ARAs on insulin sensitivity are neutral in most studies. Mechanisms of improvement of glucose tolerance and insulin sensitivity through the inhibition of the renin-angiotensin system (RAS) are complex. They may include improvement of blood flow and microcirculation in skeletal muscles and, thereby, enhancement of insulin and glucose delivery to the insulin-sensitive tissues, facilitating insulin signalling at the cellular level and improvement of insulin secretion by the beta cells. Six recent large-scale clinical studies reported a remarkably consistent reduction in the incidence of
type 2 diabetes
in hypertensive patients treated with either ACE inhibitors or ARAs for 3-6 years, compared with a thiazide diuretic, beta-adrenoceptor antagonist, the calcium channel antagonist amlodipine or even placebo. The relative risk reduction averaged 14% (p = 0.034) in the CAPPP (Captopril Prevention Project) with captopril compared with a thiazide or beta1-adrenoceptor antagonist, 34% (p < 0.001) in the HOPE (Heart Outcomes Prevention Evaluation) study with ramipril compared with placebo, 30% (p < 0.001) in the ALLHAT (Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial) with lisinopril compared with chlortalidone, 25% (p < 0.001) in the LIFE (Losartan Intervention For Endpoint reduction in hypertension study) with losartan compared with atenolol, and 25% (p = 0.09) in the SCOPE (Study on Cognition and Prognosis in the Elderly) with candesartan cilexetil compared with placebo, and 23% (p < 0.0001) in the VALUE (
Valsartan
Antihypertensive Long-term Use Evaluation) trial with valsartan compared with amlodipine. All these studies considered the development of diabetes as a secondary endpoint, except the HOPE trial where it was a post hoc analysis. These encouraging observations led to the initiation of two large, prospective, placebo-controlled randomised clinical trials whose primary outcome is the prevention of
type 2 diabetes
: the DREAM (Diabetes REduction Approaches with ramipril and rosiglitazone Medications) trial with the ACE inhibitor ramipril and the NAVIGATOR (Nateglinide And
Valsartan
in Impaired Glucose Tolerance Outcomes Research) trial with the ARA valsartan. Finally, ONTARGET (ONgoing Telmisartan Alone and in combination with Ramipril Global Endpoint Trial) will also investigate as a secondary endpoint whether it is possible to prevent the development of
type 2 diabetes
by blocking the RAS with either an ACE inhibitor or an ARA or a combination of both. Thus, the recent consistent observations of a 14-34% reduction of the development of diabetes in hypertensive patients receiving ACE inhibitors or ARAs are exciting. From a theoretical point of view, they emphasise that there are many aspects of the pathogenesis, prevention and treatment of
type 2 diabetes
that still need to be uncovered. From a practical point of view, they may offer a new strategy to reduce the ongoing epidemic and burden of
type 2 diabetes
.
...
PMID:Prevention of type 2 diabetes mellitus through inhibition of the Renin-Angiotensin system. 1551 53
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.
...
PMID:Of the renin-angiotensin system and reactive oxygen species Type 2 diabetes and angiotensin II inhibition. 1569 26
The role of the RAAS in development and maintenance of blood pressure is well established. In addition, the deleterious effects of angiotensin II on the heart, vasculature, and kidneys have been clearly defined. There seems to be a close relationship between endothelial dysfunction, insulin resistance (a precursor to diabetes and coronary artery disease) and angiotensin II. The signaling pathways for insulin in the vascular wall interacts with the angiotensin signaling, giving rise to potential mechanisms for development of diabetes and resulting harmful effects. A large number of clinical trials using ACE inhibitors or ARBs have shown significant reduction in secondary endpoints in the development of new onset of diabetes. Ongoing prospective studies involving ARBs (eg, the Nateglinide and
Valsartan
Impaired Glucose Tolerance Outcomes Research trial) and ACE inhibitors (eg, the Diabetes Re-duction Assessment with Ramipril and Rosiglita-zone Medication trial) are testing the ability of certain agents to prevent
type 2 diabetes
. In the meantime, it is important to recognize insulin resistance and metabolic syndrome as entities that increase the risk for cardiovascular disease. In addition to lifestyle modifications, managing endothelial dysfunction and protecting the vasculature will help prevent diabetes and cardiovascular disease.
...
PMID:The renin angiotensin system as a therapeutic target to prevent diabetes and its complications. 1569 45
Valsartan
as angiotensin-II receptor antagonist in normotensive diabetic may provide kidney and heart protection. It also increases insulin receptor sensitivity. The aim of this study was to investigate the effect of valsartan on lipid profile in normotensive type 2 diabetic patients. Fifteen normotensive patients with
type 2 diabetes
mellitus, mean age 58.6+/-5.6 years, with mean BMI 28.6+/-2.5 kg/m2, were treated with valsartan in doses 20-80 mg per day. After a year of treatment with valsartan we witnessed significant decrease in total cholesterol level (6.8+/-1.4 to 5.4+/-0.9 mmol/l, p<0.05) and low density lipoprotein (LDL) from 4.5 to 2.7 mmol/l. Triglycerides were not affected significantly. Albumin excretion in urine significantly decreased. Level of basal insulin (from 256 to 78 pmol/l) has, also, decreased. In
type 2 diabetes
mellitus, the use of angiotensin-II receptor antagonists reduces the progression from micro to macro albuminuria. These results suggest that the angiotensin-II receptor antagonist decreases lipid serum levels in normotensive diabetes mellitus type 2 patients.
...
PMID:The effects of valsartan on lipid profile in normotensive type 2 diabetic patients. 1613 56
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