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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diabetes mellitus is a major risk factor for coronary heart disease, peripheral vascular disease, and cardiovascular disease. The prevalence of these complications is increased about two- to four-fold in people with diabetes in the United States, and they contribute substantially to morbidity, mortality, and healthcare costs. The pathogenesis of macrovascular disease in diabetes is multifactorial. Endothelial injury is an early event, followed by macrophage adherence and uptake of lipids to produce a fatty streak. Platelet adherence, aggregation, and release of thromboxane and platelet-derived growth factors may then occur. Quantitative and qualitative alterations of lipoproteins are seen, particularly in uncontrolled insulin-dependent and non-insulin-dependent diabetes. Hyperinsulinemia may be contributory, as may elevated plasma proinsulin levels. Glycation of plasma proteins and of components of the vascular wall occurs, and altered coagulation and/or fibrinolysis may lead to thrombosis. The process is accelerated by hypertension, smoking, and hypercholesterolemia. Gliclazide is an oral sulfonylurea agent that has been reported to have actions on platelet function and fibrinolysis in addition to its effects on glycemia. The evidence for this is reviewed, and recommendations for future studies are made.
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PMID:Pathophysiology of vascular disease in diabetes: effects of gliclazide. 187 5

The standard treatment of NIDDM consists of diet, oral hypoglycaemic agents and, mostly as a last resort, insulin. Indications for insulin therapy cannot be generalized for the whole population of NIDDM patients. The defined objectives of therapy for the individual patient will determine the choice and intensity of therapy. These will usually be either a relief of hyperglycaemic symptoms in the elderly patient or normoglycaemia, as in the insulin-dependent diabetic patients, in order to prevent acute and chronic complications. Primary insulin treatment is advisable in patients with hyperglycaemic symptoms and fasting blood glucose levels above 15 mmol/l, as in these patients the major defect will be insulin deficiency rather than insulin resistance. The correction of long lasting hyperglycaemia partly restores insulin sensitivity and B cell function, thereby allowing sequential reduction of insulin dosage. When metabolic control can be sustained with low insulin dosages some of these patients may later respond well to oral hypoglycaemic agents or to diet alone. In the management of non-insulin-dependent diabetic patients it is of great importance to recognize in time when treatment with oral hypoglycaemic agents fails. Insulin therapy should not be withheld on the presumption that it will cause weight gain and will promote development of macrovascular disease. Weight gain can be reduced by adequate dietary counselling and the level of macrovascular risk factors reduces with improved metabolic control. In this context also it should be realized that the correction of hypertension, hyperlipidaemia and the cessation of cigarette smoking is probably of equal importance. Insulin therapy regimens which have been used in non-insulin-dependent diabetic patients have been the same as prescribed for insulin dependent patients. When considering the fact that hepatic overproduction of glucose is the major determinant of fasting blood glucose level and that postprandial glycaemic excursions are superimposed on this level it seems reasonable to aim for normalization of the basal hepatic glucose production. A bedtime injection of an intermediate or long acting insulin can be used for this aim. Other therapeutical approaches which have been studied recently are the use of combinations of insulin and oral hypoglycaemic agents and the use of proinsulin as an alternative for intermediate acting insulin. Before these forms of therapy can be advocated long-term clinical studies are necessary to define their therapeutic role.
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PMID:Insulin treatment of non-insulin-dependent diabetes mellitus. 307 3

The standard risk factors--dyslipidaemia, hypertension and smoking--provide little help in explaining the raised cardiovascular risk in diabetes. It can be calculated that intervening for disturbances of these risk factors could do little to rectify the loss of life expectancy of around 10 years for a middle-aged diabetic man. Three new risk factors are discussed, which together may contribute to some of the excess cardiovascular risk in diabetes. Plasminogen activator inhibitor is an inhibitor of fibrinolysis which is elevated in concentration in diabetic subjects, and may increase both the incidence of thrombotic events and the risk of reinfarction after the initial infarct. Recent work also suggests that high activity of this substance may impair pharmacological fibrinolysis. Proinsulin-like molecules are elevated in concentration in diabetic patients and correlate with levels of a number of other risk factors. Whilst these correlations may represent cause and effect for plasminogen activator inhibitor, there is no evidence that changes in levels of proinsulin-like molecules influence levels of other risk factors. Microalbuminuria provides a powerful indicator of cardiovascular risk in both diabetic and non-diabetic subjects, but whilst the mechanisms for this association are unclear, they are again unlikely to be mediated through changes in levels of standard risk factors. Recent observations of an association between short stature and microalbuminuria suggest that intrauterine or early infant nutrition may represent a common antecedent, these having also been shown to predict both components of the insulin resistance syndrome and cardiovascular disease in adult life.
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PMID:Coronary heart disease in diabetes mellitus: three new risk factors and a unifying hypothesis. 760 43

Microalbuminuria in diabetic patients is associated with ischemic heart disease and insulin resistance. We previously found a 9% prevalence of microalbuminuria in a nondiabetic population that we have reassessed, investigating associations of microalbuminuria with hypertension, dyslipidemia, hyperinsulinemia, and sodium-lithium countertransport. Of 125 subjects reexamined, 42 had been microalbuminuric 3 years previously. Twelve of these (29%) were microalbuminuric on at least one sample at follow-up, and 30 (76%) were normoalbuminuric on two. Of the 79 previously normoalbuminuric subjects, 12 (15%) became microalbuminuric on one sample, while 67 (85%) remained normoalbuminuric. Subjects who were microalbuminuric at both screening and recall were older (mean +/- SD, 65.9 +/- 11 versus 59.1 +/- 10.2 years, P = .04), with a higher waist-to-hip ratio (0.93 +/- 0.09 versus 0.86 +/- 0.08, P = .008) and at recall, on univariate analysis, had higher specific insulin (44.2 [range, 16.9 to 157.0] versus 28.4 [7.4 to 129.0] pmol/L, P = .005), intact proinsulin (5.1 [1.5 to 11.0] versus 3.0 [0.8 to 14.6] pmol/L, P = .003), and des-31,32-proinsulin (5.0 [0.5 to 9.8] versus 1.0 [0.5 to 12.2] pmol/L, P = .004) concentrations. There was also a significant difference in des-31,32-proinsulin concentration, after adjustment for covariates (P = .013), between subjects classified either as microalbuminuric or as normoalbuminuric at screening. There was no difference in body mass index; fasting blood glucose; systolic or diastolic blood pressure; total, HDL, or LDL cholesterol; triglycerides; plasminogen activator inhibitor-1; or sodium-lithium countertransport activity between consistently normoalbuminuric and persistently microalbuminuric subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Longitudinal study of associations of microalbuminuria with the insulin resistance syndrome and sodium-lithium countertransport in nondiabetic subjects. 767 Sep 46

The purpose of the study was to evaluate a relationship between HDL, triglyceride levels and insulinaemia in primary arterial hypertension. The study population consisted of 60 men aged 32-68 years (mean age 50.87 years, s.d. 8.4) with hypertension duration of 11.1 years (s.d. 6.4 years) who were compared with 60 normotensives matched for sex, age and BMI. We examined blood pressure, plasma lipoprotein content, sum of glucose and sum of insulinaemia (sum ins) during OGTT (oral glucose tolerance test). OGTT revealed insulin secretion almost twice as high in hypertensives (P < 0.001 sum ins 11002 microU min/ml, s.d. 4846) than in normotensives (sum ins 6662 microU min/ml, s.d. 3099). Comparison of concentration of selected VLDL components shows that hypertensives were characterised by markedly higher concentration of triglycerides (1.46 mmol/L, s.d. 0.87 in hypertensives and 1.04 mmol/L, s.d. 0.54 in normotensives), free and esterified cholesterol and protein, including apolipoprotein B than normotensives. It was also found that hypertensives had higher levels of apo CIII0 and lower levels of CIII1 VLDL than normotensives. Hypertensive patients showed also a higher frequency of apo E2 isoforms (three-fold) and apo E4 isoforms (two-fold) than healthy subjects. No changes were detected in the composition of LDL and HDL between the groups. Analysing the discriminating ability of biochemical parameters chosen in a step-wise manner it was found that sum ins and HDL, protein and cholesterol concentrations were the factors most powerfully differentiating men with hypertension from healthy subjects.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Relation between insulinaemia and lipoprotein composition in men with primary arterial hypertension with and without hypertriglyceridaemia. 775 72

Recent data suggest that proinsulin may be associated with increased cardiovascular risk factors in both diabetic and nondiabetic subjects. We examined the relation of insulin, proinsulin, and the fasting proinsulin/insulin ratio to a number of metabolic disorders believed to be related to the insulin resistance syndrome (low high density lipoprotein cholesterol and high triglyceride levels, hypertension, and impaired glucose tolerance). Proinsulin was measured by a RIA, and insulin was measured by a Linco RIA that does not cross-react with proinsulin. The increased fasting proinsulin/insulin ratio was significantly associated with hypertension, low high density lipoprotein cholesterol and high triglyceride levels, and impaired glucose tolerance in 423 nondiabetic subjects. The fasting proinsulin/insulin ratio increased significantly with the number of metabolic disorders (zero, 0.060; one, 0.086; two, 0.098; three, 0.177; four, 0.182; P < 0.001). The increased proinsulin/insulin ratio was also associated with a greater number of metabolic disorders in diabetic subjects. Our results show that particularly nondiabetic individuals with the insulin resistance syndrome not only have hyperinsulinemia as a marker of insulin resistance, but also show an increase in proinsulin relative to insulin, which may reflect relative beta-cell failure or malfunction.
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PMID:Disproportionately increased proinsulin levels are associated with the insulin resistance syndrome. 798 88

Recent data suggest that proinsulin is associated with cardiovascular risk factors in nondiabetic and diabetic subjects. Since most conventional insulin assays cross-react with proinsulin, it has been suggested that the associations of insulin concentrations with dyslipidemia and hypertension could actually reflect associations with proinsulin. We examined these associations by using both a conventional immunoreactive insulin assay and a specific Linco insulin assay that does not cross-react with proinsulin in 623 nondiabetic and in 180 non-insulin-dependent diabetic subjects who participated in the San Antonio Heart Study, a population-based study of diabetes and cardiovascular disease. Both the immunoreactive insulin assay and the specific Linco insulin assay were equally correlated with cardiovascular risk factors in nondiabetic subjects. Insulin concentrations were moderately correlated with high triglyceride and low high-density lipoprotein cholesterol levels and were weakly correlated with increased blood pressure. In diabetic subjects there were only weak associations between insulin and cardiovascular risk factors using either assay. We conclude that the association of insulin concentrations with cardiovascular risk factors is not a function of using insulin assays that cross-react with proinsulin and that for epidemiological studies of cardiovascular risk factors, conventional immunoreactive insulin assays are as good as the newer specific insulin assays.
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PMID:Evaluation of two insulin assays in insulin resistance syndrome (syndrome X). 806 4

Both insulin resistance and insulin concentrations correlate with blood pressure in nondiabetic subjects, but there is no consensus on these relations in subjects with non-insulin-dependent diabetes, perhaps because of the use of nonspecific insulin assays and clinic blood pressure measurement. Therefore, we have investigated the relation between ambulatory blood pressure, insulin sensitivity (measured by an insulin sensitivity test), and levels of insulin and its principal precursors, measured by specific assays, in 24 subjects with non-insulin-dependent diabetes. Insulin sensitivity (glucose metabolic clearance rate) correlated strongly with mean 24-hour ambulatory systolic blood pressure (r = -.650, P < .001). In contrast, there was no relation between this blood pressure index and fasting levels of insulin (r = .096, P = NS) or all insulin-like molecules (r = .077, P = NS). Dichotomized on 24-hour ambulatory systolic blood pressure levels, the hypertensive group was more insulin resistant than the normotensive group (metabolic clearance rate, 3.6 [0.7] versus 6.5 [3.0] mL.kg-1.min-1, P = .006), whereas there was no difference in insulin or proinsulin concentrations among the groups. In multiple regression analysis, insulin sensitivity was the major determinant of blood pressure. We conclude that in subjects with non-insulin-dependent diabetes mellitus, blood pressure is related to insulin sensitivity but not to fasting levels of insulin, suggesting that hyperinsulinemia is probably not the mediator of this relation.
Hypertension 1994 Sep
PMID:Insulin resistance, insulin, proinsulin, and ambulatory blood pressure in type II diabetes. 787 74

Recent large-scale epidemiological studies demonstrate that blood concentrations of immunoreactive insulin predict the development of NIDDM and IDDM and are associated with the risk of several degenerative diseases, such as coronary and peripheral vessel atherosclerosis, hypertension, and dyslipidemia. The reliability of these measurements is dependent on a biological assay that has not been well standardized between laboratories. Recognizing this, the American Diabetes Association organized a task force to assess comparability of blood insulin measurements between laboratories and to suggest techniques to improve comparability. The task force found that identical serum and plasma samples measured in different laboratories produced widely disparate values that were unacceptable for population comparisons. Use of a single reference standard did little to improve comparability. Assay characteristics such as linearity, recovery, accuracy, and cross-reactivity to proinsulin and its primary conversion intermediates varied among the laboratories, and they did not readily explain differences in the measurements made from assay to assay. Use of the same assay kit in different laboratories did not always ensure comparable measurements. Linear regression of assay results from one laboratory to an arbitrarily chosen reference assay greatly improved comparability and demonstrated the potential value in comparing each assay to a reference method. The task force report defines acceptable assay characteristics and proposes a three-step process of insulin assay proficiency and comparability. A central reference assay and ongoing sample exchange will be needed to allow reliable comparisons of insulin measurements made in different laboratories. Rigorous quality control and continuous quality improvement are needed to maintain reliability of the insulin measurement.
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PMID:Report of the American Diabetes Association's Task Force on standardization of the insulin assay. 854 70

GENETIC PREDISPOSITION: Insulin resistance and reactive hyperinsulinemia occur not only with obesity, impaired glucose tolerance or non-insulin-dependent (type 2) diabetes mellitus, but also in many non-obese, non-diabetic patients with essential hypertension and their currently normotensive, lean, young offspring, as well as in some other conditions known to promote hypertension. Insulin resistance impairs glucose tolerance, while insulin resistance and/or hyperinsulinemia promote dyslipidemia, body fat deposition and probably atherogenesis. Therefore, the common coexistence of a genetic predisposition for hypertension with insulin resistance helps to explain the frequent, although temporally often dissociated, occurrence of hypertension together with dyslipidemia, obesity and type 2 diabetes in a given patient. INSULIN RESISTANCE AND HYPERINSULINEMIA AS SLOW PRESSOR MECHANISMS: In the pathogenesis of hypertension, inappropriate vasoconstriction (due to an imbalance of vasoactive substances and/or raised cytosolic calcium) and/or structural vasculopathy is particularly important. Among the mosaic of assumed pressor mechanisms, distinct Na+ retention is almost invariably involved in diabetes mellitus, while sympathetic activation tends to occur in essential hypertension, particularly in association with obesity. Insulin resistance may develop as a consequence of an intracellular excess of Ca2+ or a decrease in Mg2+, an impaired insulin-mediated rise in skeletal muscle blood flow, increased sympathetic activity or excess body weight. Acute hyperinsulinemia causes arterial vasodilation on one hand and increases sympathetic activity and renal Na+ reabsorption on the other. Chronically, hyperinsulinemia may promote cardiovascular muscle cell proliferation and atherogenesis, while insulin resistance may be associated with certain transmembraneous cation transporters, leading to an increase in cytosolic Ca2+. Hyperinsulinemia and/or insulin resistance may also be associated with an increased blood pressure sensitivity to high salt intake. In the mosaic of many different blood pressure-raising mechanisms, insulin resistance and/or hyperinsulinemia is likely to represent an amplifying slow or very slow pressor factor.
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PMID:Insulin resistance and hyperinsulinemia in hypertension. 857 90


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