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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 authors give an overview on the hypothesis of the metabolic syndrome-x in accordance with insulin resistance and hyperinsulinism in triggering the development of type 2 diabetes mellitus with its clinical complexity. Dealing with the criticism of the original hypothesis, they touch the problem of protein-insufficient feeding in utero and consequences later in life. They discuss the recently emerging importance of postprandial hyperglycaemic condition, which might be even more responsible in leading to atherosclerotic lesions than the hyperinsulinism itself. Finally, they deal with the non-pharmacological intervention and drug therapy as well. A short overview of the results of the UKPDS (United Kingdom Prospective Diabetes Study) are also given, pointing out the clinical importance of correct antihyperglycaemic and antihypertensive treatment. The authors emphasise the utmost importance of early prevention in behalf of avoiding type 2 diabetes and cardiovascular complications as well.
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PMID:[Metabolic syndrome-x at the turn of the millennium (Theoretical aspects with practical consequences)]. 1118 76

Dyslipidaemia is an important component of the metabolic syndrome observed in patients with type 2 diabetes, and is characterized by moderate hypertriglyceridaemia and low levels of high-density lipoprotein (HDL) cholesterol concentrations. Dyslipidaemia contributes to increased vascular risk and is therefore a good target for therapeutic intervention in the form of glycaemic control, lifestyle measures and hypolipidaemic drugs. It is proposed that lipid abnormalities in type 2 diabetes are secondary consequences of insulin resistance. Any approach that lowers insulin resistance would be anticipated to have a beneficial effect on dyslipidaemia, but in many cases patients with type 2 diabetes fail to achieve normal lipidaemia through diet, exercise and glycaemic control. Subgroup analyses of major clinical trials suggests that lipid-lowering therapy reduces CHD risk in patients with diabetes, but trials performed specifically in populations of patients with diabetes are ongoing. Until then, patients with type 2 diabetes who have established CHD or high individual risk already warrant aggressive lipid-lowering pharmacotherapy. In the author's view, when ongoing studies are complete it is likely that most patients with type 2 diabetes will be prescribed lipid-lowering drugs.
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PMID:Diabetic dyslipidaemia. 1122 57

The metabolic syndrome is characterized by a clustering of cardiovascular risk factors including type 2 diabetes mellitus, hypertension, dyslipidemia, and obesity. Elevated plasma insulin and urinary norepinephrine (noradrenaline) and reduced urinary epinephrine (adrenaline) excretion are associated with obesity in Caucasian populations. We examined the interrelationships between obesity, plasma insulin, and urinary catecholamine excretion in Chinese subjects with various components of the metabolic syndrome. A total of 577 Chinese subjects (aged 38 +/- 10 years; 68% with type 2 diabetes mellitus, hypertension, dyslipidemia, obesity, and/or albuminuria and 32% healthy subjects) were studied, all of whom had a plasma creatinine less than 150 micromol/L. The blood pressure, height, weight, waist and hip circumference, and fasting plasma glucose, insulin, lipid, and creatinine levels were measured. A 24-hour urine sample was collected for measurement of albumin and catecholamine excretion. The body mass index (BMI) and waist circumference were used as measures of general and central obesity, respectively. The insulin resistance index was estimated by the calculated product of fasting plasma insulin and glucose concentrations. Patients with an increasing number of components of the metabolic syndrome (type 2 diabetes mellitus, hypertension, dyslipidemia, obesity, and/or albuminuria) were more obese, hyperglycemic, dyslipidemic, and albuminuric and had higher blood pressure, plasma insulin, insulin resistance indices, and 24-hour urinary norepinephrine excretion but lower urinary epinephrine output (all P < .005). Increasing quintiles of BMI in the whole population or waist circumference in both sexes were associated with increasing trends for adverse lipid profiles, plasma insulin, insulin resistance indices, and urinary norepinephrine excretion but a decreasing trend for urinary epinephrine output (all P < .001). There were close associations between age, obesity, blood pressure, fasting plasma glucose, lipid, insulin, insulin resistance indices, and urinary catecholamine excretion. Using stepwise multiple regression analysis (all P < .001), 34% of the variability of the BMI and 45% of that of the waist circumference were independently related to gender (waist higher in males and BMI higher in females), increased plasma insulin, triglyceride, and urinary norepinephrine excretion, and decreased high-density lipoprotein (HDL) cholesterol and urinary epinephrine output. In Chinese subjects with different manifestations of the metabolic syndrome, hyperinsulinemia, insulin resistance, elevated norepinephrine, and reduced epinephrine excretion were closely associated with general and central obesity. Based on these findings, we postulate that complex interactions between the insulin and sympathoadrenal systems may lead to the development of obesity and the metabolic syndrome.
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PMID:Urinary epinephrine and norepinephrine interrelations with obesity, insulin, and the metabolic syndrome in Hong Kong Chinese. 1122 19

The objective of this study was to investigate possible defects in the insulin sensitivity and/or the acute insulin response in a group of Mexican patients displaying early-onset type 2 diabetes and to evaluate the contribution of mutations in three of the genes linked to maturity-onset diabetes of the young. We studied 40 Mexican patients with an age of diagnosis between 20 and 40 yr in which the insulin sensitivity as well as the insulin secretory response were measured using the minimal model approach. A partial screening for possible mutations in 3 of the 5 genes linked to maturity-onset diabetes of the young was carried out by PCR-single strand conformation polymorphism analysis. A low insulin secretory capacity (AIRg = 68.5 +/- 5 muU/mL.min) and a near-normal insulin sensitivity (3.43 +/- 0.2 min/muU.mL x 10(4)) were found in these patients. Among this group we found two individuals carrying missense mutations in exon 4 of the hepatocyte nuclear factor-1alpha (HNF-4alpha) gene (Asp(126)-->His/Tyr and Arg(154)-->Gln, respectively) and one carrying a nonsense mutation in exon 7 of the HNF-1alpha gene (Gln(486)-->stop codon); 7.5% had positive titers for glutamic acid decarboxylase antibodies. Thirty-five percent of cases had insulin resistance; these subjects had the lipid abnormalities seen in the metabolic syndrome. A defect in insulin secretion is the hallmark in Mexican diabetic patients diagnosed between 20 and 40 yr of age. Mutations in either the HNF-1alpha or the HNF-4alpha genes are present among the individuals who develop early-onset diabetes in our population. These particular sequence changes have not been previously reported and therefore represent putative new mutations. Even in the absence of endogenous hyperinsulinemia, insulin resistance is associated with an adverse lipid profile.
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PMID:Early-onset type 2 diabetes: metabolic and genetic characterization in the mexican population. 1123 4

Insulin resistance is a change in physiologic regulation such that a fixed dose of insulin causes less of an effect on glucose metabolism than occurs in normal individuals. The normal compensatory response to insulin resistance is an increase in insulin secretion that results in hyperinsulinemia. If the hyperinsulinemia is sufficient to overcome the insulin resistance, glucose regulation remains normal; if not, type 2 diabetes ensues. Associated with insulin resistance, however, is a cluster of other metabolic abnormalities involving body fat distribution, lipid metabolism, thrombosis and fibrinolysis, blood pressure regulation, and endothelial cell function. This cluster of abnormalities is referred to as the insulin resistance syndrome or the metabolic syndrome. It is causally related not only to the development of type 2 diabetes but also to cardiovascular disease. A major unresolved issue is whether there is a single underlying cause of this syndrome and, if so, what might it be? Several promising hypotheses have been proposed. There are some data to support the hypothesis that fetal malnutrition imprints on metabolic regulatory processes that, in later adult life, predispose to the development of the insulin resistance syndrome. Visceral obesity also has been a candidate for the cause of the syndrome. Whatever mechanism is ultimately found to be responsible, it will undoubtedly have both genetic and environmental components. Among the biochemical mediators that are likely to be responsible for the interference with insulin's effects on intermediary metabolism are free fatty acids and other products from adipose tissue. Recent data suggest that the substances stimulate serine phosphorylation of molecules involved in the initial steps of insulin action, thereby blocking the ability of these molecules to be tyrosine phosphorylated and initiate the subsequent steps of the insulin action cascade. The thiazolidinediones are a new class of agents that have been developed to treat type 2 diabetic patients. These drugs act as peroxisome proliferator-activated receptor gamma (PPARgamma) agonists. Following their binding to the receptor, the heterodimer molecule that contains the binding site is activated. The activated complex binds to the response elements of specific genes that regulate molecules that effect insulin action and lipid metabolism. These genes are either activated or inhibited. Specifically, the thiazolidinediones improve insulin action and decrease insulin resistance. The exact mechanism by which these agents decrease insulin resistance is not clear but they do decrease the elevated free fatty acid levels present in insulin-resistant patients and they appear to change the body distribution of adipose tissue. Treatment of insulin-resistant type 2 diabetic patients with thiazolidinediones not only improves glycemic control and decreases insulin resistance, it also improves many of the abnormalities that are part of the insulin resistance syndrome.
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PMID:Insulin resistance and its treatment by thiazolidinediones. 1123 17

The relation between isolated low HDL-cholesterol and the components of the metabolic syndrome is poorly known in type 2 diabetes. We evaluated cardiovascular risk parameters in type 2 diabetic patients with low HDL-cholesterol, compared to those with low HDL-cholesterol and hypertriglyceridemia, isolated hypertriglyceridemia and normal lipid parameters. Patients with low HDL-cholesterol/high triglycerides had higher BMI (29.6 +/- 5.7 vs 27.9 +/- 4.4 or vs 28.1 +/- 5.2 kg/m(2) ), prevalence of obesity (69% vs 55% or vs 54%), higher levels of uric acid (339.0 +/- 83.3 vs 303.3 +/- 95.2 or vs 303.3 +/- 89.2 micromol/l) and C-peptide (0.76 +/- 0.40 vs 0.63 +/- 0.33 or vs 0.63 +/- 0.36 nmol/l) and number of components of the metabolic syndrome (27% patients with all the components) compared to patients with isolated low HDL-cholesterol or normal subjects, respectively. A similar pattern of values was evident in patients with isolated hypertriglyceridemia. With logistic regression analysis, BMI and uric acid levels were significantly associated with the presence of hypertriglyceridemia (both isolated or associated with low HDL-cholesterol), while patients with isolated low HDL-cholesterol and those without dyslipidemia displayed a similar more favourable metabolic pattern. These results indicate that low HDL-cholesterol is a component of the metabolic syndrome only in the presence of fasting hypertriglyceridemia in type 2 diabetic patients.
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PMID:Low HDL-cholesterol: a component of the metabolic syndrome only in the presence of fasting hypertriglyceridemia in type 2 diabetic patients. 1124 Apr 43

This is a review of research carried out in Japanese Americans that points towards possible approaches to prevention of type 2 diabetes mellitus. The natural history of type 2 diabetes usually includes both insulin resistance and beta-cell dysfunction. Insulin secretion may compensate for insulin resistance. Alternatively, enhanced insulin sensitivity may mask an insulin secretory defect. Epidemiological data support the view that in the vast majority of cases of type 2 diabetes, insulin resistance is essential to the pathogenesis of hyperglycemia. Increased diabetes prevalence as ethnic groups migrate to more urban or westernized regions has been attributed to increased occurrence of insulin resistance. Research among Japanese Americans in Seattle, Washington, showed a higher prevalence of type 2 diabetes than in Japan, which suggested that factors associated with 'westernization' might be playing a role in bringing out underlying susceptibility to diabetes. Our research has shown that these impressions were correct and that the abnormalities that characterize the metabolic syndrome play a significant role. Due to increased intra-abdominal fat deposition, Japanese Americans were likely to be 'metabolically obese' despite relatively normal BMI. A diet higher in animal fat and lower levels of physical activity were risk factors leading to increased intra-abdominal fat deposition, insulin resistance, and diabetes. Information from epidemiological studies such as these may be used to determine whether diabetes may be prevented through changes in lifestyle or application of specific therapies targeted towards identified metabolic abnormalities.
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PMID:Preventing diabetes--applying pathophysiological and epidemiological evidence. 1124 64

As the relationships between C-peptide levels and metabolic control and chronic complications are poorly known in type 2 diabetes, due to the slow decline of beta-cell function, we evaluated these associations in a cohort of type 2 diabetic patients. After excluding insulin-treated subjects, 1,533 patients were divided according to their C-peptide fasting levels in quartiles. Patients within the lowest C-peptide quartile showed significantly higher duration of diabetes, prevalence of retinopathy and values of HDL-cholesterol, albumin excretion rate and HbA1c, while BMI, diastolic blood pressure, percentages of hypertension and metabolic syndrome, and values of triglycerides and uric acid were significantly higher in the highest C-peptide quartile. The associations between C-peptide and duration of diabetes, AER, HbA1c, retinopathy and the components of the metabolic syndrome remained significant, after multiple adjustments. In conclusion, these data support the hypothesis that a reduced insulin secretion is associated with a longer duration of diabetes and a greater prevalence of microvascular complications, while higher insulin levels are associated with the components of the metabolic syndrome.
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PMID:Relationship of residual beta-cell function, metabolic control and chronic complications in type 2 diabetes mellitus. 1127 12

In Caenorhabditis elegans, an insulin-like signalling pathway culminates in a transcription factor (TF) that is homologous to a subfamily of TFs responsible for the regulation of a subset of insulin-responsive genes in humans. Under harsh conditions, C. elegans reduces signalling through this pathway and arrests developmentally in a manner that is similar to the metabolic syndrome of humans. We propose that an understanding of this pathway could lead to drugs with optimal potency and selectivity in the treatment of type 2 diabetes mellitus.
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PMID:Type 2 diabetes mellitus and worm longevity: a transcriptional link to cure? 1129 62

The definable causes of nonalcoholic steatohepatitis (NASH) include jejunoileal bypass surgery (JIB), other causes of rapid and profound weight loss in obese subjects, total parenteral nutrition, drugs, industrial toxins, copper toxicity, and disorders characterized by extreme insulin resistance. However, the etiopathogenesis in most cases of NASH appears multifactorial. Obesity, type 2 diabetes, and hypertriglyceridemia are often associated with hepatic steatosis, and although this does not invariably lead to NASH, the fatty liver is vulnerable to hepatocellular injury initiated by reactive oxygen species (ROS). It is critical to understand not only the triggers for hepatitis (injury and inflammation) in NASH but also how this is perpetuated as chronic liver disease. The present focus is on whether the biochemical processes that generate oxidative stress lead to hepatocyte injury and secondary recruitment of inflammation or whether inflammation is the primary mediator of liver cell injury. Insulin resistance is a reproducible pathogenic factor in NASH. It favors accumulation of free fatty acids in the liver and predisposes to oxidative stress by stimulating microsomal lipid peroxidases and by the direct effects of high insulin levels in decreasing mitochondrial beta-oxidation. CYP2E1 is normally suppressed by insulin but is invariably increased in the livers of patients with NASH. In rodent dietary models of steatohepatitis, CYP2E1 is the catalyst of microsomal lipid peroxidation, while in Cyp 2e1 nullizygous mice, CYP4A proteins are induced and function as alternative microsomal lipid peroxidases. Other studies implicate activation of peroxisome proliferator-activated receptor-alpha (PPAR alpha) as leading to NASH; PPAR alpha is a transcription factor that governs both microsomal (via CYP4A) and peroxisomal (beta-oxidation) pathways of lipid oxidation and ultimately production of ROS. Increased lipid peroxidation is a crucial difference between the livers of rodents with experimental NASH and those of ob/ob genetically obese mice that have uncomplicated steatosis. Administration of endotoxin, through the release of tumor necrosis factor-alpha (TNF-alpha), provokes liver inflammation with hepatocyte injury in the steatotic liver. This may be particularly relevant in JIB and has been suggested as a pathogenic mechanism in primary NASH. It has been proposed that inheriting one or more copies of the hemochromatosis gene, C282Y, promotes fibrotic progression in NASH because of increased hepatic iron deposition, but recent studies have failed to confirm this. The relationship between the severity of hepatitis in NASH and progression to cirrhosis implies that products of the inflammatory infiltrate play a role in fibrogenesis. In summary, NASH can be regarded as the hepatic consequence of the metabolic syndrome (or syndrome X). Attention should now shift from steatosis, a generally benign process that is less evident in the advanced stages of cirrhosis, to the mechanisms for hepatocellular injury, inflammation, and hepatic fibrosis. In particular, the genetic, molecular, and cellular factors that ordain and moderate fibrosis in the context of steatohepatitis will be of greatest relevance to effective therapy and clinical outcome.
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PMID:Etiopathogenesis of nonalcoholic steatohepatitis. 1129 94

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