Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.20 (alpha-glucosidase)
 4,237 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acarbose is an alpha-glucosidase inhibitor which delays the absorption of glucose from the intestine. Taken orally before a meal, acarbose delays absorption of carbohydrates and decreases the postprandial plasma glucose and plasma insulin rise. A pilot study has been carried out to investigate whether acarbose can improve insulin sensitivity in subjects with impaired glucose tolerance (IGT). 18 subjects were randomized to receive either acarbose, 100 mg t.d.s., or placebo for 16 weeks. Acarbose therapy was found to decrease 2-hour plasma glucose and plasma insulin levels and to increase insulin sensitivity. Insulin resistance is an important factor in the development of non-insulin dependent diabetes mellitus (NIDDM).these results suggest that acarbose therapy may be able to prevent or delay the progression of IGT to NIDDM. A multicentre phase III clinical trial is now planned to investigate this possibility.
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PMID:The effect of acarbose on insulin sensitivity in subjects with impaired glucose tolerance. 868 58

Obesity is common in NIDDM; in a cohort of 314 diabetics in Singapore, 44.3% are overweight. Management of obesity in diabetics differs from that in non-diabetics in that it is more urgent; weight maintenance is more difficult and hypoglycaemic medication may cause weight changes. Like in the non-diabetic, management of obesity in diabetic requires a pragmatic and realistic approach. A team approach is required: the help of the nurse educator, the dietitian, behaviour modification therapist, exercise therapist etc are required. A detailed history, careful physical examination and relevant investigations are required to assess the severity of the diabetic state and to exclude an occasional underlying cause of the obesity in the obese NIDDM. Weight loss is urgent in the obese NIDDM, especially those with android obesity. There must be a reduction in caloric intake. Weight loss leads to improvement in the glucose tolerance, insulin sensitivity, reduction in lipid levels and fall in blood pressure in the hypertensive. Exercise is of limited value except in the younger obese NIDDM. Metformin is the hypoglycaemic drug of choice as it leads to consistent weight reduction. The sulphonylureas may cause weight gain. Insulin should be avoided where possible as it causes further weight gain. Other hypoglycaemic agents include Glucobay (alpha-glucosidase inhibitor) and Troglitazone (insulin sensitizer) which do not alter the weight. Orlistat (lipase inhibitor) is promising as it causes reduction of weight, blood-glucose and lipid levels. Anti-obesity drugs (noradrenergic and serotonergic agents) have modest effects on weight reduction in the obese NIDDM; a widely use preparation, Dexfenfluramine (Adifax) has been withdrawn because of side effects. Surgery such as gastric plication is the last resort in treating the morbidly obese NIDDM. The discovery of leptin in 1994 has led to intense research into energy homeostasis in obesity; hopefully this will lead to better treatment of obesity in diabetics and non-diabetics.
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PMID:Management of obesity in NIDDM (non-insulin-dependent diabetes mellitus). 984 3

Effects of voglibose (an alpha-glucosidase inhibitor) and pioglitazone (an insulin sensitizer) on glycemic control and on the function of pancreatic islets were evaluated using Goto-Kakizaki (GK) rats with non-insulin-dependent diabetes mellitus (NIDDM). Five week administration (8-13 weeks of age in GK rats) of voglibose alone (added to the chow at a concentration of 10 ppm), pioglitazone alone (10 mg/kg daily p.o.), or both of the agents together significantly improved fasting plasma glucose levels and those at 120 min in oral glucose tolerance tests. Insulin secretory capacity in response to glucose of the isolated islets, assessed by batch incubation, was significantly improved in the voglibose and in the voglibose plus pioglitazone groups. Eight-week administration (5-13 weeks of age) of voglibose and voglibose plus pioglitazone successfully lowered the fasting levels of plasma glucose and triglyceride. The glucose-responsiveness in insulin release from the islets was also significantly recovered by the therapy. The treatment increased the insulin content of the islets to almost twice that in untreated controls. Thus, treatment by these drugs can not only effectively ameliorate the metabolic derangement of NIDDM in GK rats, but it can also restore the deteriorated islet function, possibly through protection from glucose toxicity.
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PMID:Beneficial effect of long-term combined treatment with voglibose and pioglitazone on pancreatic islet function of genetically diabetic GK rats. 991 84

Oral anti-diabetic agents with hypoglycemic action via mechanisms distinct from the sulfonylureas have recently been developed. One of these, alpha-glucosidase inhibitor slows the absorption rate of carbohydrate from the small intestine. Effects of voglibose on glycemic control and on the function of pancreatic islets were evaluated using Goto-Kakizaki (GK) rats with non-insulin-dependent diabetes mellitus (NIDDM). Insulin secretory capacity in response to glucose of islets was significantly improved after 8-week administration of voglibose. The treatment increased the insulin content of the islets to almost twice that in untreated controls. Thus, the treatment can restore the deteriorated islet function of GK rats, possibly through protection from glucose toxicity.
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PMID:[alpha-Glucosidase inhibitor]. 1019 52

The use of insulin in elderly patients raises special considerations. Most people who develop diabetes mellitus late in life have type 2 diabetes mellitus, in which there is some residual endogenous insulin secretion. This pancreatic insulin secretion, when present, stabilises their metabolic status. However, some elderly people lose virtually all their endogenous insulin secretory capacity over time, or may even have type 1 (autoimmune) diabetes mellitus with no endogenous insulin. Generally, older patients with diabetes mellitus can be managed for years, often decades, with nutritional therapy and oral agents. More options exist now than did previously. In addition to a variety of sulfonylureas, there is metformin, troglitazone, and/or alpha-glucosidase inhibitors, that are viable options to be used before turning to insulin. The goals of insulin therapy in the elderly must be considered. When hyperglycaemia causes symptoms (polyuria, polydypsia and bodyweight loss) blood glucose levels are generally >200 mg/dl, and insulin is needed if maximal doses of oral agents have been used. Insulin is also indicated when hyperglycaemia puts patients at risk of hyperosmolar states, for example, when blood glucose is >300 mg/dl during a normal day. Clinical judgement dictates whether to use insulin to control glycaemia in the attempt to avoid long term complications such as neuropathy, retinopathy or nephropathy. In people with relatively short life expectancy, major comorbities and no sign of diabetic complications, the risk may be small. On the other hand, in patients for whom neuropathy, in particular, is a major risk, controlling glycaemia (with insulin if necessary) does reduce that risk. Most patients with type 2 diabetes mellitus can be managed with relatively simple insulin regimens thanks to their endogenous insulin secretion. A single bedtime dose of neutral protamine Hagedorn (NPH) insulin, with or without continuation of daytime oral agents, may control fasting blood glucose. A pre-mix combination of NPH and Regular insulin such as 70/30 or 50/50 may be used pre-meal. More customised, 'intensive' insulin regimens are needed when the glycaemia is unstable. Hypoglycaemia is clearly the most significant risk of insulin therapy. If mild and easily treated, it is of no real concern. On the other hand, nocturnal hypoglycaemia, and, in particular, hypoglycaemia unawareness, are clear signs that the insulin regimen should be modified. In summary, insulin therapy may be necessary, and can be used effectively, in elderly patients. However, risk:benefit considerations must be taken into account when deciding which patients to treat with insulin and what insulin regimen to use.
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PMID:Feasibility and outcomes of insulin therapy in elderly patients with diabetes mellitus. 1040 37

Most patients with type 2 (non-insulin-dependent) diabetes mellitus require pharmacotherapy, initially as monotherapy and subsequently in combination, as adjuncts to diet and exercise. Exogenous insulin is ultimately required in a substantial proportion, reflecting the progressive natural history of the disease. Sulphonylureas and biguanides have been employed for over 4 decades as oral antidiabetic agents, but they have a limited capacity to provide long term glycaemic control and can cause serious adverse effects. Thus, more efficacious and tolerable antidiabetic agents are required. Recent years have witnessed the introduction of agents with novel modes of action, that is, the alpha-glucosidase inhibitors acarbose and miglitol (which reduce postprandial hyperglycaemia) and the first of the thiazolidinedione insulinsensitising drugs--troglitazone and rosiglitazone. Although the former has been withdrawn in some countries due to adverse effects, another 'glitazone' pioglitazone is expected to be approved in the near future. Other recently introduced drugs include glimepiride and the meglitinide insulin secretagogue, repaglinide. Attention is also focusing increasingly on combination therapy using insulin together with sulphonylureas, metformin or troglitazone. Rapid-acting insulin analogues are now being used as alternatives to conventional insulins; their role in the management of type 2 diabetes mellitus is presently uncertain but reports of a reduced frequency of hypoglycaemia are encouraging. The development of new drugs aims to counter the principal metabolic defects of the disorder, respectively, relative insulin deficiency and insulin resistance. Novel classes of rapid-acting secretagogues under evaluation include the morphilinoguanide BTS 67582 and the meglitinides mitiglinide (KAD 1229) and senaglinide (A-4166). Succinate ester derivatives represent a potential novel approach to improving beta-cell function through enhancement of insulin biosynthesis and secretion. Enhancement of nutrient-induced insulin secretion is a mechanism with several putative targets within the beta-cell; potentiators of insulin secretion include glucagon-like peptide-1 and its analogues, phosphodiesterase inhibitors and the imidazoline derivative PMS 812 (S 21663). The amylin agonist pramlintide slows gastric emptying and suppression of glucagon secretion. Non-thiazolidinedione insulin-sensitising agents include the gamma-receptor agonist G 1262570X (GG 570) and D-chiro-inositol. Insulin analogues with prolonged action and inhaled insulin preparations are also under investigation. Insulin-mimetic agents include organic vanadium compounds. Whether newer agents will offer clinically relevant efficacy and tolerability advantages over existing therapies remains to be determined.
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PMID:Recent developments and emerging therapies for type 2 diabetes mellitus. 1082 Jun 47

Traditional oral anti-diabetic agents for the treatment of diabetes mellitus include the sulfonylureas, metformin, and the alpha-glucosidase inhibitors. Insulin has traditionally been used in various forms with an aim to mimic physiological insulin secretion patterns. Combinations of any of these treatment classes have also been utilized for their additive effects. All of these options have specific advantages and disadvantages, making them ideal for certain patients and less ideal for others. Each of these treatment classes is briefly discussed with respect to mechanisms of action, clinical efficacy, side-effects and current controversies associated with their use. Newer agents (such as the thiazolidinediones, newer insulin secretagogues, and insulin analogues) will be discussed elsewhere.
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PMID:Established therapies for diabetes mellitus. 1236 15

The therapeutic goals in patients with type 2 diabetes mellitus and the mechanisms of insulin resistance and secretion are discussed. Sulfonylureas improve glycemic control, restore the acute insulin response, and help improve beta-cell function in the short term. Meglitinides and phenylalanine derivatives and alpha-glucosidase inhibitors may be useful for elderly patients and others with normal fasting blood glucose levels and postprandial hyperglycemia, but they are less effective in achieving goal HbA1c levels in patients with marked fasting hyperglycemia. Metformin and thiazolidinediones act on hepatic, muscle, and adipose tissue through different mechanisms to improve glycemic control, beta-cell function, and the lipid profile. Thiazolidinediones have a greater impact on free fatty acids than metformin. They may have an additive effect with sulfonylureas, metformin, or insulin in improving glycemic control and the lipid profile. Many patients require combination therapy with one or more insulin sensitizers and an insulin secretagogue to achieve therapeutic goals. Insulin therapy should be initiated in patients in whom an HbA1c level less than 7.0% cannot be maintained with other therapies. This is vital in preventing diabetes complications. Insulin sensitizers should be continued during insulin therapy to reduce insulin resistance and treat the insulin resistance syndrome. Therapeutic goals for patients with type 2 diabetes mellitus include improvement in glycemic control and prevention of diabetes complications. Elevated levels of fasting blood glucose should be addressed before postprandial levels to reduce HbA1c levels and glucotoxicity to the beta cell. Dyslipidemia, hypertension, and hypercoagulability should be treated to minimize the increased cardiovascular risk seen in people with diabetes, which is responsible for the majority of deaths.
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PMID:Treating dual defects in diabetes: insulin resistance and insulin secretion. 1248 81

Insulin resistance plays an important role in the pathogenesis of metabolic syndrome and hence an improvement of insulin resistance is important in the treatment of metabolic syndrome. Oral hypoglycemic agents such as thiazolidinediones and biguanides improve glycemic control by reducing insulin resistance. Furthermore, it has been clarified that they also have anti-dyslipidemic, anti-hypertensive and anti-atherosclerotic actions. In addition, such an insulin sensitizing effect has been demonstrated when alpha-glucosidase inhibitors, statins, fibrates and hypotensive agents such as ACE inhibitors, calcium channel blockers and ARBs have been given to patients with insulin resistance. These drugs should be used for each patient on the basis of the underlying diseases, in addition to a lifestyle modification.
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PMID:[Total care for patients with metabolic syndrome]. 1520 58

Type 2 diabetes mellitus is a progressive and complex disorder that is difficult to treat effectively in the long term. The majority of patients are overweight or obese at diagnosis and will be unable to achieve or sustain near normoglycaemia without oral antidiabetic agents; a sizeable proportion of patients will eventually require insulin therapy to maintain long-term glycaemic control, either as monotherapy or in conjunction with oral antidiabetic therapy. The frequent need for escalating therapy is held to reflect progressive loss of islet beta-cell function, usually in the presence of obesity-related insulin resistance. Today's clinicians are presented with an extensive range of oral antidiabetic drugs for type 2 diabetes. The main classes are heterogeneous in their modes of action, safety profiles and tolerability. These main classes include agents that stimulate insulin secretion (sulphonylureas and rapid-acting secretagogues), reduce hepatic glucose production (biguanides), delay digestion and absorption of intestinal carbohydrate (alpha-glucosidase inhibitors) or improve insulin action (thiazolidinediones). The UKPDS (United Kingdom Prospective Diabetes Study) demonstrated the benefits of intensified glycaemic control on microvascular complications in newly diagnosed patients with type 2 diabetes. However, the picture was less clearcut with regard to macrovascular disease, with neither sulphonylureas nor insulin significantly reducing cardiovascular events. The impact of oral antidiabetic agents on atherosclerosis--beyond expected effects on glycaemic control--is an increasingly important consideration. In the UKPDS, overweight and obese patients randomised to initial monotherapy with metformin experienced significant reductions in myocardial infarction and diabetes-related deaths. Metformin does not promote weight gain and has beneficial effects on several cardiovascular risk factors. Accordingly, metformin is widely regarded as the drug of choice for most patients with type 2 diabetes. Concern about cardiovascular safety of sulphonylureas has largely dissipated with generally reassuring results from clinical trials, including the UKPDS. Encouragingly, the recent Steno-2 Study showed that intensive target-driven, multifactorial approach to management, based around a sulphonylurea, reduced the risk of both micro- and macrovascular complications in high-risk patients. Theoretical advantages of selectively targeting postprandial hyperglycaemia require confirmation in clinical trials of drugs with preferential effects on this facet of hyperglycaemia are currently in progress. The insulin-sensitising thiazolidinedione class of antidiabetic agents has potentially advantageous effects on multiple components of the metabolic syndrome; the results of clinical trials with cardiovascular endpoints are awaited. The selection of initial monotherapy is based on a clinical and biochemical assessment of the patient, safety considerations being paramount. In some circumstances, for example pregnancy or severe hepatic or renal impairment, insulin may be the treatment of choice when nonpharmacological measures prove inadequate. Insulin is also required for metabolic decompensation, that is, incipient or actual diabetic ketoacidosis, or non-ketotic hyperosmolar hyperglycaemia. Certain comorbidities, for example presentation with myocardial infarction during other acute intercurrent illness, may make insulin the best option. Oral antidiabetic agents should be initiated at a low dose and titrated up according to glycaemic response, as judged by measurement of glycosylated haemoglobin (HbA1c) concentration, supplemented in some patients by self monitoring of capillary blood glucose. The average glucose-lowering effect of the major classes of oral antidiabetic agents is broadly similar (averaging a 1-2% reduction in HbA1c), alpha-glucosidase inhibitors being rather less effective. Tailoring the treatment to the individual patient is an important principle. Doses are gradually titrated up according to response. However, the maximal glucose-lowering action for sulphonylureas is usually attained at appreciably lower doses (approximately 50%) than the manufacturers' recommended daily maximum. Combinations of certain agents, for example a secretagogue plus a biguanide or a thiazolidinedione, are logical and widely used, and combination preparations are now available in some countries. While the benefits of metformin added to a sulphonylurea were initially less favourable in the UKPDS, longer-term data have allayed concern. When considering long-term therapy, issues such as tolerability and convenience are important additional considerations. Neither sulphonylureas nor biguanides are able to appreciably alter the rate of progression of hyperglycaemia in patients with type 2 diabetes. Preliminary data suggesting that thiazolidinediones may provide better long-term glycaemic stability are currently being tested in clinical trials; current evidence, while encouraging, is not conclusive. Delayed progression from glucose intolerance to type 2 diabetes in high-risk individuals with glucose intolerance has been demonstrated with troglitazone, metformin and acarbose. However, intensive lifestyle intervention can be more effective than drug therapy, at least in the setting of interventional clinical trials. No antidiabetic drugs are presently licensed for use in prediabetic individuals.
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PMID:Oral antidiabetic agents: current role in type 2 diabetes mellitus. 1566 80


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