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Query: UMLS:C0011860 (type 2 diabetes)
 57,723 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The term X syndrome involves several dilemmas. The terminological dilemma is that this term is used to describe microvascular angina pectoris, as well as Reaven's metabolic-hormonal syndrome and our 5H syndrome [association of hyperinsulinism with arterial hypertension, hyperlipoproteinaemia, hyperglycaemia (NIDDM) and hirsutism]. It is probable that the coronary X syndrome is frequently conditioned by the hormonal-metabolic X syndrome. The pathogenetic dilemma is that it is not clear why in microvascular angina pectoris the coronary circulation does not possess an adequate reserve for vasodilatation during exercise or in response to some pharmacological stimuli. This could condition hyperinsulinism in hypertonic subjects with NIDDM with an early disorder of paracrine endothelial relaxation mechanisms (EDRF-NO), with a predominance of vasoconstrictor mechanisms (endothelin-1). In Reaven's syndrome X it is not clear whether insulin resistance of the postreceptor type is a primary inborn phenomenon which is compensated by insulin hypersecretion or whether it is a secondary phenomenon, which develops ex post and by which the target tissues defend themselves against an excessive effect of insulin (e.g. down regulation receptors) in primary disorders of its secretion.
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PMID:[The dilemma of syndrome X]. 149 65

In one third of patients who suffered an infarction NIDDM and arterial hypertension are present. In the absolute majority of patients with IHD, as apparent from the IRI and C-peptide response after a glucose load, hyperinsulinism is present. The blood sugar response can have the character of diabetes or of impaired glucose tolerance, the curve may be very flat or normal while the IRI and C-peptide response are excessive. Hyperinsulinism has a hypersecretory origin as suggested by the concurrently elevated C-peptide level but also reduced insulin utilization in the liver and peripheral target organs. Hyperinsulinism is thus a regular associated phenomenon of IHD and is a special risk factor independent on hyperglycaemia and associates with the other main risk factors of IHD such as arterial hypertension, HPLP (android obesity), hyperglycaemia (NIDDM) and hirsutism as a manifestation of a hyperandrogenic state in the female organism with the syndrome of polycystic ovaries. Hyperinsulinism plays an indirect role in the pathogenesis of coronary syndrome via the main risk factors (5H syndrome--hyperinsulinism, hypertension, HPLP, hyperglycaemia, hirsutism) and also directly by its action on endothelial paracrine mechanism of the coronary circulation where in the early stage vasoconstrictor factors predominate (endothelin-1, PGF2-alpha) over physiological vasodilatating factors (EDRF-NO, PGE2, PGI2) and this leads then to functional spasms. It seems that also the coronary X syndrome develops very frequently on the background of the hormonal metabolic X syndrome or the 5H syndrome.
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PMID:[Hyperinsulinism and the coronary syndrome]. 149 68

To investigate whether circulating endothelin-1 (Et-1) may be related to the increased incidence and severity of ischaemic heart disease in type 2 diabetes mellitus, we compared the concentrations in type 2 diabetic patients and in non-diabetic patients with coronary artery disease (CAD) angiographically documented. Plasma levels of Et-1 were determined in 34 type 2 diabetic patients with CAD (16 with stable angina, 6 with unstable angina, 12 with previous myocardial infarction) and in 19 nondiabetic patients with CAD (4 with stable angina, 5 with unstable angina, 10 with previous myocardial infarction). Fifteen diabetic patients without CAD and 9 healthy volunteers served as control subjects. In the type 2 diabetic patients, the mean Et-1 levels were 3.19 +/- 1.61 pmol/l in those with stable angina, 3.58 +/- 1.92 pmol/l in those with unstable angina, 4.24 +/- 2.53 pmol/l in those with myocardial infarction. These values were not significantly different one another, nor from the values obtained from type 2 diabetic controls (3.64 +/- 2.13 pmol/l). In the non-diabetic patients, the mean Et-1 levels were 3.92 +/- 0.73 pmol/l in those with stable angina, 4.35 +/- 1.67 pmol/l in those with unstable angina, 4.33 +/- 1.66 pmol/l in those with myocardial infarction. These values were not significantly different one another, but significantly higher than those obtained from healthy controls (2.07 +/- 0.67 pmol/l; P < 0.001). No significant differences were found in Et-1 levels between diabetic and non-diabetic patients with stable, unstable angina and previous myocardial infarction. In contrast, a statistically significant difference was found in Et-1 levels between diabetic and non-diabetic control subjects (P < 0.05). In conclusion, similar raised concentrations of Et-1 in diabetic and non-diabetic patients with stable, unstable angina and previous myocardial infarction do not support the hypothesis that higher levels of Et-1 in diabetic patients are responsible for the increased incidence of CAD in diabetes mellitus. However, the raised Et-1 levels found in diabetic patients in the absence of CAD strongly suggest that a generalised endothelial dysfunction, documented in our study by increased levels of Et-1, most probably precedes subsequent cardiovascular diseases.
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PMID:Circulating endothelin-1 levels in type 2 diabetic patients with ischaemic heart disease. 890 34

Several reports indicate higher endothelin-1 (ET-1) levels in patients with non insulin dependent diabetes mellitus (NIDDM), although this finding has not been confirmed by other studies. The discrepancy may be partially explained by the frequent coexistence in NIDDM patients of other pathologies, such as essential hypertension, and by the presence of diabetic vascular complications or renal failure, able, per se, to increase ET-1 circulating levels. This study aimed to evaluate the influence of arterial hypertension and/or of diabetic angiopathy on ET-1 circulating levels in a group of NIDDM patients. We measured ET-1 plasma concentrations in three groups of subjects: a) 22 NIDDM patients with or without hypertension and with or without vascular complications; b) 11 hypertensive patients; c) 14 age-matched healthy volunteers. Plasma ET-1 concentrations were significantly higher in NIDDM patients with angiopathy (7.3 +/- 0.7 pg/ml, mean +/- Standard Error; p < 0.001) than diabetics without angiopathy (4.4 +/- 0.53 pg/ml), hypertensive patients (4.7 +/- 0.85 pg/ml) and healthy subjects (3.1 +/- 0.19 pg/ml). This report indicates that increased plasma ET-1 levels in NIDDM patients may be ascribed only to those with vascular compliances, while hypertension, per se, does not affect ET-1 plasma levels in these patients.
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PMID:Vascular damage and not hypertension per se influences endothelin-1 plasma levels in patients with non insulin dependent diabetes mellitus. 927 Feb 91

While insulin is known to promote vascular smooth muscle (VSM) relaxation, it also enhances endothelin-1 (ET-1) secretion and action in conditions such as NIDDM and hypertension. We examined the effect of insulin pretreatment on intracellular free calcium ([Ca2+]i) responses to ET-1 in cultured aortic smooth muscle cells (ASMCs) isolated from Sprague-Dawley (SD) rats and measured ET(A) receptor characteristics and ET-1-evoked tension responses in aorta obtained from insulin-resistant, hyperinsulinemic Zucker-obese (ZO) and control Zucker-lean (ZL) rats. Pretreatment of rat ASMCs with insulin (10 nmol/l for 24 h) failed to affect basal [Ca2+]i levels but led to a significant increase in peak [Ca2+]i response (1.7-fold; P < 0.01) to ET-1. The responses to IRL-1620 (an ET(B) selective agonist), ANG II, and vasopressin remained unaffected. ET-1-evoked peak [Ca2+]i responses were significantly attenuated by the inclusion of the ET(A) antagonist, BQ123, in both groups. The ET(B) antagonist, BQ788, abolished [Ca2+]i responses to IRL-1620 but failed to affect the exaggerated [Ca2+]i responses to ET-1. Saturation binding studies revealed a twofold increase (P < 0.01) in maximal number of binding sites labeled by 125I-labeled ET-1 in insulin-pretreated cells and no significant differences in sites labeled by 125I-labeled IRL-1620 between control and treatment groups. Northern blot analysis revealed an increase in ET(A) mRNA levels after insulin pretreatment for 20 h, an effect that was blocked by genistein, actinomycin D, and cycloheximide. Maximal tension development to ET-1 was significantly greater (P < 0.01), and microsomal binding studies using [3H]BQ-123 revealed a twofold higher number of ET(A) specific binding sites (P < 0.01) in aorta from ZO rats compared with that of ZL rats. These data suggest that insulin exaggerates ET-1-evoked peak [Ca2+]i responses via increased vascular ET(A) receptor expression, which may contribute to enhanced vasoconstriction observed in hyperinsulinemic states.
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PMID:Insulin increases endothelin-1-evoked intracellular free calcium responses by increased ET(A) receptor expression in rat aortic smooth muscle cells. 960 72

Endothelin-1 is mainly synthesized by the vascular endothelial cells and acts on the vascular smooth muscle. Because of its vasoconstrictor and mitogenic effects it plays a role in the development of vascular diseases. In diabetes mellitus atherosclerosis is accelerated. The authors summarize the available data of the role of endothelin-1 in Type 1 and Type 2 diabetes mellitus and the development of diabetic complication.
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PMID:Role of endothelin-1 in diabetes mellitus. 967 69

To evaluate the role of circulating and renal endothelin-1 (ET-1) in early diabetic nephropathy, plasma ET-1 levels and urinary ET-1 excretion were evaluated in lean, normotensive patients affected by non-insulin-dependent diabetes (NIDDM) either with (n = 9, NIDDM+) or without microalbuminuria (n = 18, NIDDM-); in never-treated, lean, essential hypertensive patients with (n = 12, EH+) or without microalbuminuria (n = 10, EH-); and in healthy volunteers (n = 12). Results showed higher plasma ET-1 levels in NIDDM+ (1.97 +/- 0.58 pg/mL) than in NIDDM- (1.59 +/- 0.14 pg/mL, P = .013), EH+ (1.40 +/- 0.21 pg/mL, P = .005), EH- (0.91 +/- 0.19 pg/mL, P < .0001), and controls (0.60 +/- 0.10 pg/mL, P < .0001). The circulating ET-1 concentration was also higher in EH+ than EH- and controls (P < .0001). Urinary ET-1 excretion did not differ (P = .387, NS) between NIDDM+ (48.5 +/- 20.1 pg/min) and NIDDM- (40.9 +/- 21.6 pg/min), but was significantly reduced (P < .0001) in both groups compared with controls (70.0 +/- 15.5 pg/min). Similar findings were observed in hypertensive subgroups. No correlations were found between urinary ET-1 and other variables, including plasma ET-1 levels, in all groups. In conclusion, NIDDM+ is accompanied by a significant increase in plasma ET-1 levels. A significant elevation of circulating ET-1 concentration was evident also in NIDDM-, suggesting that early abnormalities of ET-1 production might precede the microalbuminuric phase of diabetes-related renal damage.
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PMID:Role of plasma and urinary endothelin-1 in early diabetic and hypertensive nephropathy. 971 92

Leptin levels in subjects with android obesity with the insulin resistance syndrome (syndrome X, 5H) are in general elevated, as compared with non-obese subjects and correlate with the BMI, with the percentage of body fat, WHR, IRI levels and sex (they are higher in women), as it is the case in the general population. In the elevated leptin level in syndrome 5H (association of hyperinsulinism, hyperglycaemia-NIDDM, hyperlipoproteinaemia with android obesity, arterial hypertension and hirsutism in females with the polycystic ovaries syndrome) participate in a significant way also elevated basal IRI and cortisol levels as well as an elevated postprandial IRI response during oGTT despite the fact that leptin and endothelin-1 levels do not rise significantly during oGTT despite hyperinsulinaemia. Leptin levels were however higher in men (liminally significant in women) with an hyperinsulinaemic response during oGTT, as compared with probands with a normal insulin response. Optimal insulin and glucocorticoid levels are the prerequisite for a rise of leptin because proadipocytes in vitro begin to produce leptin as soon as insulin is added to the medium and this effect is trebled, if cortisol is added. It appears that the insulin and leptin resistance in syndrome 5H are parallel phenomena which potentiate each other. Elevated insulin and cortisol levels maintain elevated leptin levels which in turn enhances the insulin resistance in muscles and at the same time has an impact on the IRI response to postprandial hyperglycaemia. In the background of this insulin and leptin resistance in the majority of subjects with the 5H syndrome there is apparently no actual molecular defect of the hormone and its receptors in target tissues but a possible defect in mechanisms of postreceptor transduction of the hormonal signal. In the hormonal resistance participate moreover also two general and non-specific mechanisms such as: 1. increased consumption or uptake of hormonal receptors by elevated levels of the appropriate hormone ("down regulation" phenomenon), 2. disorders of paracrine endothelial mechanisms of the vascular wall which determine via the control of the inflow in the regional microcirculation the availability of insulin, leptin and metabolic substrates to target tissues. Impaired vasodilatation reserves and the development of paradoxical vascular spasms in response to stimuli which normally cause vasodilatation (strain, administration of acetylcholine, histamine, ATP etc.) are constant, associated phenomena in hyperlipoproteinaemias, arterial hypertension and in type 2 diabetics. These phenomena are the syndrome of insulin resistance and syndrome 5H-X resp. Endothelin-1 levels assessed in the systemic circulation are however due to their short biological half-life and the paracrine action of endothelin-1 not sensitive markers of endothelial dysfunction in syndrome X.
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PMID:[Relation between levels of leptin, insulin and cortisol in persons with the 5H (X) syndrome]. 982 79

Several recent studies indicate that type 2 diabetes, arterial hypertension, lipid disorders as well as visceral obesity are coronary risk factors which might belong to a syndrome which is caused by decreased insulin sensitivity with compensatory hyperinsulinaemia. More than 50% of patients with essential hypertension have some degree of insulin resistance, but in contrast to dyslipoproteinaemia and glucose intolerance the causal relation between insulin resistance and elevated arterial blood pressure appears not to be as evident. One explanation is that the link between blood pressure and insulin sensitivity might be mainly related to concomitant obesity. Accordingly, obesity can be associated with an increased activity of the sympathetic nervous system, elevated plasma levels of the vasoconstrictor endothelin-1, and decreased insulin-induced endothelium-dependent vasodilation. Furthermore, adipocytes can secrete vasogenic peptides, such as angiotensinogen. Since insulin resistance is a polygenic disorder, the two basic genetic approaches we follow is to identify genetic defects of insulin action in cells of patients with inherited syndromes of insulin resistance and to characterize molecular mechanisms of insulin regulated gene expression. The results show that insulin can affect the expression rate of various genes, e.g. involved in cholesterol and fatty acid metabolism, by modulating the activity of transcription factors coupled to the MAP kinase cascade and that a genetic postreceptor defect in these intracellular signaling pathways might have a pleiotropic effect on cell metabolism and clinical phenotype.
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PMID:Metabolic syndrome and hypertension: pathophysiology and molecular basis of insulin resistance. 983 75

Insulin stimulates endothelin-1 (ET-1) expression in a dose-response relationship, and ET-1 effects on vascular wall structure are similar to the long-term complications of diabetes. We therefore determined whether the plasma ET-1 concentration in patients with diabetes is associated with their total insulin exposure to see if plasma ET-1 might be a link between insulin exposure and long-term complications of diabetes. We studied 69 patients with Type I and 40 patients with Type II diabetes mellitus in equally tight glycaemic control for 2 years in a cross-sectional design. We measured basal and glucagon-stimulated plasma C-peptide, abdominal sagittal diameter, skinfold thickness, glomerular filtration rate, albumin excretion rate and standard clinical characteristics. Mean HbA1c was 6.4% in Type I and 6.3% in Type II diabetes. Patients with an albumin excretion rate >300 microg/min were excluded. Adjusted mean plasma ET-1 was 4.11 (S.E.M. 0.39) pg/ml in 21 normal subjects, 3.47 (0.19) pg/ml in Type I diabetes and 4.84 (0.26) pg/ml in Type II diabetes (P=0.0001). In all patients with measurable plasma C-peptide, plasma ET-1 was associated with basal plasma C-peptide (r=0.5018, P<0.0001), with stimulated plasma C-peptide (r=0.5379, P<0.0001), and with total daily insulin dose (r=0.2219, P=0.00851). Abdominal obesity, metabolic abnormalities, blood pressure and glomerular filtration rate were not associated with plasma ET-1, when corrected for C-peptide and daily insulin dose. Our study shows that the plasma concentration of ET-1 is closely associated with insulin secretion and insulin dose in patients with diabetes. Plasma ET-1 is higher in Type II diabetes than in Type I diabetes. Increased insulin exposure in patients with diabetes may have long-term effects on vascular wall structure through its stimulation of ET-1 expression.
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PMID:Plasma endothelin-1 and total insulin exposure in diabetes mellitus. 1040 69


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