Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0011854 (type 1 diabetes)
 20,749 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pancreatic beta-cells are sensitive to a number of proapoptotic stimuli. Thus, apoptosis is an important part of the physiological neonatal remodeling of the endocrine pancreas, and a number of pathological stimuli involved in type 1 and type 2 diabetes have been shown to elicit beta-cell apoptosis. Factors of relevance to type 1 diabetes include proinflammatory cytokines, nitric oxide, and reactive oxygen species as well as Fas ligand. Recent findings that free fatty acids, glucose, sulfonylurea, and amylin cause beta-cell apoptosis in vitro suggest that programmed cell death may also be involved in the pathogenesis of type 2 diabetes. Furthermore, there is evidence favoring a convergence in signaling pathways toward common effectors of beta-cell apoptosis elicited by stimuli implicated in the pathogenesis of type 1 and type 2 diabetes. Therefore, recent studies involving the stimuli and signaling pathways of beta-cell apoptosis-in particular, mitogen- and stress-activated protein kinases-will be reviewed. It is concluded that immunological, inflammatory, and metabolic signals cause beta-cell apoptosis, and the possibility that these signals converge toward a common beta-cell death signaling pathway should be investigated further.
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PMID:beta-cell apoptosis: stimuli and signaling. 1127 4

Amylin (AMY) is a 37 amino acid peptide cosecreted with insulin (INS) by pancreatic beta-cells and absent in type 1 diabetes, a condition frequently associated with osteopenia. AMY binds to calcitonin receptors, lowers plasma calcium concentration, inhibits osteoclast activity, and stimulates osteoblasts. In the present study, we examined the effects of AMY replacement on bone loss in a streptozotocin (STZ)-induced rodent model type 1 diabetes. Of 50 male Wistar rats studied, 40 were made diabetic with intraperitoneal STZ (50 mg/kg; plasma glucose concentrations > 11 mM within 5 days). Ten nondiabetic control (CONT) rats received citrate buffer without STZ. Diabetic rats were divided into four groups (n = 10/group) and injected subcutaneously with rat AMY (45 mg/kg), INS (12 U/kg), both (same doses), or saline (STZ; diabetic controls) once per day. After 40 days of treatment and five 24-h periods of urine collection for deoxypyridinoline (DPD), the animals were killed, blood was sampled, and femurs were removed. The left femur was tested for mechanical resistance (three-point bending). The right femur was tested for total, diaphyseal (cortical bone), and metaphyseal (trabecular bone) bone densities using dual-energy X-ray absorptiometry (DXA). Bone was ashed to determine total bone mineral (calcium) content. None of the treatments had any significant effect on femoral length and diameter. Untreated diabetic rats (STZ; 145+/-7N) had lower bone strength than did nondiabetic CONT (164+/-38; p < 0.05). Total bone mineral density (BMD; g/cm2) was significantly lower in STZ (0. 2523+/-0.0076) than in CONT (0.2826+/-0.0055), as were metaphyseal and diaphyseal densities. Diabetic rats treated with AMY, INS, or both had bone strengths and bone densities that were indistinguishable from those in nondiabetic CONT. Changes in bone mineral content paralleled those for total BMD (T-BMD). Plasma osteocalcin (OC) concentration, a marker for osteoblastic activity, was markedly lower in untreated diabetic rats (7. 6+/-0.9 ng/ml); p < 0.05) than in nondiabetic CONT (29.8+/-1.7; p < 0.05) or than in AMY (20.1+/-0.7; p < 0.05). Urinary DPD excretion, a marker for bone resorption, was similar in untreated and AMY-treated diabetic rats (35.0+/-3.1 vs. 35.1+/-4.4 nmol/mmol creatinine), intermediate in rats treated with INS (49.9+/-2.7), and normalized in diabetic rats treated with both agents (58.8+/-8.9 vs. 63.2+/-4.5 in CONT). Thus, in our STZ rat model of diabetic osteopenia, addition of AMY improved bone indices apparently by both inhibiting resorption and stimulating bone formation.
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PMID:Amylin and bone metabolism in streptozotocin-induced diabetic rats. 1134 42

Mealtime amylin replacement with the human amylin analog pramlintide as an adjunct to insulin therapy improves postprandial glycemia and long-term glycemic control in type 1 diabetes. Preclinical animal studies indicate that these complementary effects may result from at least 2 independent mechanisms: a slowing of nutrient delivery to the small intestine and a suppression of nutrient-stimulated glucagon secretion. The former effect of pramlintide has previously been demonstrated in patients with type 1 diabetes. The present studies characterize the effect of pramlintide on postprandial glucagon secretion in this patient population. Plasma glucagon and glucose concentrations were measured before and after a standardized liquid meal in 2 separate randomized, double-blind, placebo-controlled studies of pramlintide administration to patients with type 1 diabetes. In a 2-day crossover study, 18 patients received a 5-hour intravenous infusion of pramlintide (25 microg/h or 50 microg/h) or placebo in addition to subcutaneous (SC) insulin injections. In a 14-day parallel-group study, 84 patients received SC injections of 30, 100, or 300 microg of pramlintide or placebo 3 times daily in addition to SC injections of insulin. In both studies plasma glucagon concentrations increased in response to the meal in the placebo-plus-insulin group but not in any of the pramlintide-treated groups (all pramlintide treatment arms v placebo, P <.05). We conclude that mealtime amylin replacement with pramlintide prevents the abnormal meal-related rise in glucagonemia in insulin-treated patients with type 1 diabetes, an effect that likely contributes to its ability to improve postprandial glucose homeostasis and long-term glycemic control.
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PMID:The human amylin analog, pramlintide, corrects postprandial hyperglucagonemia in patients with type 1 diabetes. 1197 98

Besides dietary approaches, various pharmacological means have been recently developed in order to better control postprandial hyperglycaemia. This objective may be obtained: 1) by slowing down the intestinal absorption of carbohydrates; 2) by insuring a better insulin priming soon after the meal; and 3) by inhibiting post-prandial glucagon secretion or action. Some hormones (amylin, glucagon-like peptide-1) can slow gastric emptying while alpha-glucosidase inhibitors (acarbose, miglitol) retard intestinal digestion and resorption of complex carbohydrates. A more physiological post-meal profile of insulin may be obtained in type 2 diabetes by using new insulin secretagogues of the glinide family (repaglinide, nateglinide) with an earlier and shorter insulinotropic action or, mainly in type 1 diabetes but also in type 2 diabetes, by using short-acting insulin analogues (lispro. Asp B28) or inhated insulin the action of which is faster than that of subcutaneous insulin. Post-prandial glucagon secretion can be inhibited by amylin. GLP-1 or insulin while other glucagon antagonists are currently in development.
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PMID:[Postprandial hyperglycemia. II. Pharmacological approaches]. 1207 90

Recent availability of expanded treatment options for both type 1 and type 2 diabetes has not translated into easier and significantly better glycemic and metabolic management. Patients with type 1 diabetes continue to experience increased risk of hypoglycemic episodes and progressive weight gain resulting from intensive insulin treatment, despite the recent availability of a variety of insulin analog. Given the progressive nature of the disease, most patients with type 2 diabetes inevitably proceed from oral agent monotherapy to combination therapy and, ultimately, require exogenous insulin replacement. Insulin therapy in type 2 diabetes is also accompanied by untoward weight gain. Both type 1 and type 2 diabetes continue to be characterized by marked postprandial hyperglycemia. Two hormones still in development are candidates for pharmacologic intervention, have novel modes of action (some centrally mediated), and show great promise in addressing some of the unmet needs of current diabetes management. Pramlintide acetate, an analog of the beta cell hormone amylin and the first non-insulin related therapeutic modality for type 1 and type 2 diabetic patients with severe beta cell failure, may be useful as adjunctive therapy to insulin. The principal anti-diabetic effects of pramlintide arise from interactions via its cognate receptors located in the central nervous system resulting in postprandial glucagon suppression, modulation of nutrient absorption rate, and reduction of food intake. Another polypeptide hormone, exendin-4, exerts at least some of its pharmacologic actions as an agonist at the glucagon-like peptide-1 (GLP-1) receptor. GLP-1 and related compounds exhibit multiple modes of action, the most notable being a glucose-dependent insulinotropic effects and the potential to preserve or improve the beta-cell function. The latter effect could potentially halt or delay the progressive deterioration of the diabetic state associated with type 2 diabetes. Physiologically, both amylin and glucagon-like peptide (GLP)-1, along with insulin, are involved in a coordinated and concerted interplay between hormones acting both centrally and peripherally to provide meticulous control over the rate of appearance of exogenous and endogenous glucose and to match that rate to the rate of glucose disappearance. Both hormones are deficient in diabetes. Therapies directed at restoring this complex physiology have the potential to facilitate glucose control and thus minimize the attendant complications of diabetes.
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PMID:Novel peptides under development for the treatment of type 1 and type 2 diabetes mellitus. 1247 97

Adis CommentsPramlintide [AC 0137, AC 137, tripro-amylin, Symlin] is a synthetic human amylin analogue with proline substitutions at positions 25, 28 and 29, which limits the self-aggregation seen with native amylin. Pramlintide improves glycaemic control, and appears to reduce postprandial blood glucose peaks and flatten the glucose peaks and troughs observed in diabetic patients. The reduction of hypoglycaemia would be an immediate advantage, and the reduction of hyperglycaemia could potentially prevent diabetic complications. Development - US: Amylin has submitted an NDA in the US for pramlintide acetate (Symlin trade mark ) as an adjunctive therapy for the treatment of type 1 and type 2 diabetes mellitus. However, the FDA's Endocrinologic and Metabolic Drugs Advisory Committee at their meeting on 26 July 2001, voted not to recommend approval of pramlintide for type 1 and type 2 diabetes. Although eight out of nine Committee members were convinced of the potential of pramlintide therapy, the Committee expressed concerns regarding safety issues and requested additional data addressing these concerns. Finally, on 12 October 2001, Amylin received an 'approvable letter' for Symlin- for the treatment of diabetes. In April 2002, Amylin commenced a trial in 250 patients with type 1 diabetes to evaluate the safety issues regarding cases of severe hypoglycaemia with pramlintide in combination with insulin reported in this group of patients. The trial will investigate dose titration in the initial first month of the treatment period combined with insulin adjustment for the optimisation of glucose control. Patients are then treated for 6 months at a steady-state dose of pramlintide or placebo, accompanied by the additional insulin adjustments. Amylin has completed patient enrolment in September 2002. Final approval is subject to satisfactory results from this safety and dose titration study and the four small pharmacology studies already completed or underway. Amylin plans to file an amendment to the pramlintide's NDA in the Q1 of 2003. Development - non-USA: A wholly owned subsidiary of Amylin Pharmaceuticals, Amylin Europe, filed a regulatory submission with the European Agency for Evaluation of Medicinal Products (EMEA) and Switzerland for pramlintide for the treatment of both type 1 and type 2 diabetes under the centralised procedure. Amylin completed pivotal phase III clinical trials with pramlintide acetate (Symlin trade mark ) for the treatment of type 1 and type 2 diabetes mellitus in North America and Europe. However, in October 2002, Amylin announced that following consultation with the Committee for Proprietary Medicinal Products (CPMP) of the EMEA, it has found that additional information is necessary to proceed with review of the MAA for pramlintide for diabetes. Since, the centralised procedure does not allow the adding of new information to the application that is already under review, Amylin has decided to withdraw the MAA for pramlintide. The company will continue discussions with the EMEA to clarify the information required for a resubmission of the application. The submission for pramlintide in Switzerland is currently under review. In a separate phase II programme, Amylin is investigating the use of pramlintide in type 2 diabetes mellitus patients who are not achieving satisfactory results with oral hypoglycaemic agents but who have not progressed to using insulin. Collaborations: Pramlintide was under joint development with Amylin Pharmaceuticals and Johnson and Johnson, as an injectable partner hormone for insulin for the treatment of both type 1 and type 2 diabetes mellitus. The terms of the agreement between Amylin and Johnson and Johnson were that Amylin had primary responsibility for development and regulatory submissions, while Johnson and Johnson had primary responsibility for marketing; development costs and eventual profits were to be shared equally. Later, Johnson and Johnson decided to terminate the collaboration to commercialise pramlintide. An earlier development collaboration betweion between Amylin and Glaxo Wellcome was also discontinued. However, Amylin is in new ongoing discussions with collaborative partners for pramlintide in Europe and Japan. Amylin has signed an agreement with CP Pharmaceuticals in the UK to manufacture pramlintide.
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PMID:Pramlintide: (AC 137, AC 0137, Symlin, Tripro-Amylin). 1253 23

Group B coxsackieviruses (CVBs) have a well-established association with type 1 diabetes but the mechanism of depletion of beta-cell mass following infection has not yet been defined. In this report we show that the major difference in pathogenesis between the E2 diabetogenic strain of CVB4 and the prototypic JVB strain in SJL mice is not in tropism for islet cells but in the degree of damage inflicted on the exocrine pancreas and the resulting capacity for regeneration of both acinar and islet tissue by the host. Both strains replicated to a high titre in acinar tissue up to day 3 post-infection (p.i.), while the islets of Langerhans were largely spared. However, the pancreas in the JVB-infected animals then regenerated and many small islets were seen throughout the tissue by day 10 p.i. In contrast, the acinar tissue in E2-infected mice became increasingly necrotic until all that remained by day 21 p.i. were large islets containing varying numbers of dead cells, caught up in strands of connective tissue. Surviving beta cells were found to synthesize little insulin, although islet amyloid polypeptide was detected and glucagon synthesis in alpha cells appeared normal or enhanced. Our results suggest that the key to CVB-E2-induced damage lies in the exocrine tissue and prevention of islet neogenesis rather than from direct effects on existing islets.
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PMID:Lack of islet neogenesis plays a key role in beta-cell depletion in mice infected with a diabetogenic variant of coxsackievirus B4. 1457 10

Type 1 diabetes is an autoimmune disease in which pancreatic beta-cells are destroyed by cytotoxic T-cells that recognize peptide epitopes presented by HLA class I molecules. The identification of human beta-cell epitopes may significantly improve the prospects for immunodiagnosis and immunotherapy in type 1 diabetes. Using algorithms to predict nonameric beta-cell peptides that would bind to the common HLA allele, HLA-A*0201, we identified a potential epitope from the leader sequence of islet amyloid polypeptide (human islet amyloid polypeptide [IAPP] precursor protein [preproIAPP] 5-13: KLQVFLIVL). Peripheral blood mononuclear cells (PBMCs) were isolated from 18 HLA-A*0201 patients with type 1 diabetes (9 with recent-onset [<180 days; range, 1-120 days] and 9 with long-standing diabetes [>180 days; range, 183-3,273 days]) and 9 healthy, nondiabetic control subjects. PBMCs were screened for peptide recognition using interferon-gamma enzyme-linked immunospot (ELISpot) assays. Of the nine patients with recent-onset type 1 diabetes, six had ELISpot responses to preproIAPP 5-13 that were >3 SDs above the mean of the nondiabetic control subjects (P = 0.002). In contrast, no patients with type 1 diabetes for >180 days had a response above this threshold. In summary, preproIAPP 5-13 is a novel HLA class I epitope recognized by a significant proportion of cytotoxic T-cells from HLA-A*0201 patients with recent-onset type 1 diabetes and may prove to be a useful tool for the prediction and/or prevention of this disease.
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PMID:Identification of a beta-cell-specific HLA class I restricted epitope in type 1 diabetes. 1457 81

Despite a number of incremental, beneficial improvements in diabetes mellitus therapy over the past few decades, the fundamental challenge of replicating the physiological entry into, and uptake of glucose from, the circulation remains unresolved. Pramlintide is an analogue of the beta-cell hormone amylin that simulates its important glucoregulatory actions. In humans, pramlintide slows gastric emptying and suppresses glucagon secretion during the prandial/postprandial period to slow and reduce the entry of glucose into the circulation. These actions, in conjunction with the glucose cellular uptake function of insulin, help normalise fluctuations in circulating glucose levels to a greater degree than is possible with insulin treatment alone. In clinical studies, pramlintide treatment as an adjunct to insulin decreased glycosylated haemoglobin levels (0.39-0.62%) with a concomitant weight loss (0.5-1.4kg) and no significant increase in severe hypoglycaemia. Pramlintide treatment as a potential adjunct to insulin therapy is in late-stage development for patients with type 1 diabetes and insulin-using patients with type 2 diabetes.
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PMID:Pramlintide for the treatment of insulin-requiring diabetes mellitus: rationale and review of clinical data. 1521 59

Efforts toward routine islet cell transplantation as a means for reversing type 1 diabetes have been hampered by islet availability as well as allograft rejection. In vitro transdifferentiation of mouse bone marrow (BM)-derived stem (mBMDS) cells into insulin-producing cells could provide an abundant source of autologous cells for this procedure. For this study, we isolated and characterized single cell-derived stem cell lines obtained from mouse BM. In vitro differentiation of these mBMDS cells resulted in populations meeting a number of criteria set forth to define functional insulin-producing cells. Specifically, the mBMDS cells expressed multiple genes related to pancreatic beta-cell development and function (insulin I and II, Glut2, glucose kinase, islet amyloid polypeptide, nestin, pancreatic duodenal homeobox-1 [PDX-1], and Pax6). Insulin and C-peptide production was identified by immunocytochemistry and confirmed by electron microscopy. In vitro studies involving glucose stimulation identified glucose-stimulated insulin release. Finally, these mBMDS cells transplanted into streptozotocin-induced diabetic mice imparted reversal of hyperglycemia and improved metabolic profiles in response to intraperitoneal glucose tolerance testing. These results indicate that mouse BM harbors cells capable of in vitro transdifferentiating into functional insulin-producing cells and support efforts to derive such cells in humans as a means to alleviate limitations surrounding islet cell transplantation.
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PMID:In vivo and in vitro characterization of insulin-producing cells obtained from murine bone marrow. 1522 Jan 96


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