The role of prandial pramlintide in the treatment of adolescents with type 1 diabetes

A model of subcutaneous pramlintide pharmacokinetics and its effect on gastric emptying: Proof-of-concept based on populational data

Pramlintide, an amylin analog, has been coming up as an agent in type 1 diabetes dual-hormone therapies (insulin/pramlintide). Since pramlintide slows down gastric emptying, it allows for easing glucose control and reducing the burden of meal announcements. Pre-clinical in silico evaluations are a key step in the development of any closed-loop strategy. However, mathematical models are needed, and pramlintide models in the literature are scarce. This work proposes a proof-of-concept pramlintide model, describing its subcutaneous pharmacokinetics (PK) and its effect on gastric emptying (PD). The model is validated with published populational (clinical) data. The model development is divided into three stages: intravenous PK, subcutaneous PK, and PD modeling. In each stage, a set of model structures are proposed, and their performance is assessed using the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC). In order to evaluate the modulation of the rate of gastric emptying, a literature meal model was used. The final pramlintide model comprises four compartments and a function that modulates gastric emptying depending on plasma pramlintide. Results show an appropriate fit for the data. Some aspects are left as open questions due to the lack of specific data (e.g., the influence of meal composition on the pramlintide effect). Moreover, further validation with individual data is necessary to propose a virtual cohort of patients.

S100A9 exerts insulin-independent antidiabetic and anti-inflammatory effects

Type 1 diabetes mellitus (T1DM) is characterized by insulin deficiency leading to hyperglycemia and several metabolic defects. Insulin therapy remains the cornerstone of T1DM management, yet it increases the risk of life-threatening hypoglycemia and the development of major comorbidities. Here, we report an insulin signaling-independent pathway able to improve glycemic control in T1DM rodents. Co-treatment with recombinant S100 calcium-binding protein A9 (S100A9) enabled increased adherence to glycemic targets with half as much insulin and without causing hypoglycemia. Mechanistically, we demonstrate that the hyperglycemia-suppressing action of S100A9 is due to a Toll-like receptor 4-dependent increase in glucose uptake in specific skeletal muscles (i.e., soleus and diaphragm). In addition, we found that T1DM mice have abnormal systemic inflammation, which is resolved by S100A9 therapy alone (or in combination with low insulin), hence uncovering a potent anti-inflammatory action of S100A9 in T1DM. In summary, our findings reveal the S100A9-TLR4 skeletal muscle axis as a promising therapeutic target for improving T1DM treatment.

THERAPY OF ENDOCRINE DISEASE: Amylin and calcitonin - physiology and pharmacology

Type 2 diabetes is a common manifestation of metabolic dysfunction due to obesity and constitutes a major burden for modern health care systems, in concert with the alarming rise in obesity worldwide. In recent years, several successful pharmacotherapies improving glucose metabolism have emerged and some of these also promote weight loss, thus, ameliorating insulin resistance. However, the progressive nature of type 2 diabetes is not halted by these new anti-diabetic pharmacotherapies. Therefore, novel therapies promoting weight loss further and delaying diabetes progression are needed. Amylin, a beta cell hormone, has satiating properties and also delays gastric emptying and inhibits postprandial glucagon secretion with the net result of reducing postprandial glucose excursions. Amylin acts through the six amylin receptors, which share the core component with the calcitonin receptor. Calcitonin, derived from thyroid C cells, is best known for its role in humane calcium metabolism, where it inhibits osteoclasts and reduces circulating calcium. However, calcitonin, particularly of salmon origin, has also been shown to affect insulin sensitivity, reduce the gastric emptying rate and promote satiation. Preclinical trials with agents targeting the calcitonin receptor and the amylin receptors, show improvements in several parameters of glucose metabolism including insulin sensitivity and some of these agents are currently undergoing clinical trials. Here, we review the physiological and pharmacological effects of amylin and calcitonin and discuss the future potential of amylin and calcitonin-based treatments for patients with type 2 diabetes and obesity.

Effects of Dietary Fat and Protein on Glucoregulatory Hormones in Adolescents and Young Adults With Type 1 Diabetes

CONTEXT

Dietary fat and protein impact postprandial hyperglycemia in people with type 1 diabetes, but the underlying mechanisms are poorly understood. Glucoregulatory hormones are also known to modulate gastric emptying and may contribute to this effect.

OBJECTIVE

Investigate the effects of fat and protein on glucagon-like peptide (GLP-1), glucagon-dependent insulinotropic polypeptide (GIP) and glucagon secretion.

METHODS

2 crossover euglycemic insulin clamp clinical trials at 2 Australian pediatric diabetes centers. Participants were 12-21 years (n = 21) with type 1 diabetes for ≥1 year. Participants consumed a low-protein (LP) or high-protein (HP) meal in Study 1, and low-protein/low-fat (LPLF) or high-protein/high-fat (HPHF) meal in Study 2, all containing 30 g of carbohydrate. An insulin clamp was used to maintain postprandial euglycemia and plasma glucoregulatory hormones were measured every 30 minutes for 5 hours. Data from both cohorts (n = 11, 10) were analyzed separately. The main outcome measure was area under the curve of GLP-1, GIP, and glucagon.

RESULTS

Meals low in fat and protein had minimal effect on GLP-1, while there was sustained elevation after HP (80.3 ± 16.8 pmol/L) vs LP (56.9 ± 18.6), P = .016, and HPHF (103.0 ± 26.9) vs LPLF (69.5 ± 31.9) meals, P = .002. The prompt rise in GIP after all meals was greater after HP (190.2 ± 35.7 pmol/L) vs LP (152.3 ± 23.3), P = .003, and HPHF (258.6 ± 31.0) vs LPLF (151.7 ± 29.4), P < .001. A rise in glucagon was also seen in response to protein, and HP (292.5 ± 88.1 pg/mL) vs LP (182.8 ± 48.5), P = .010.

CONCLUSION

The impact of fat and protein on postprandial glucose excursions may be mediated by the differential secretion of glucoregulatory hormones. Further studies to better understand these mechanisms may lead to improved personalized postprandial glucose management.

Ultra-Fast Insulin-Pramlintide Co-Formulation for Improved Glucose Management in Diabetic Rats

Dual-hormone replacement therapy with insulin and amylin in patients with type 1 diabetes has the potential to improve glucose management. Unfortunately, currently available formulations require burdensome separate injections at mealtimes and have disparate pharmacokinetics that do not mimic endogenous co-secretion. Here, amphiphilic acrylamide copolymers are used to create a stable co-formulation of monomeric insulin and amylin analogues (lispro and pramlintide) with synchronous pharmacokinetics and ultra-rapid action. The co-formulation is stable for over 16 h under stressed aging conditions, whereas commercial insulin lispro (Humalog) aggregates in 8 h. The faster pharmacokinetics of monomeric insulin in this co-formulation result in increased insulin-pramlintide overlap of 75 ± 6% compared to only 47 ± 7% for separate injections. The co-formulation results in similar delay in gastric emptying compared to pramlintide delivered separately. In a glucose challenge, in rats, the co-formulation reduces deviation from baseline glucose compared to insulin only, or separate insulin and pramlintide administrations. Further, comparison of interspecies pharmacokinetics of monomeric pramlintide suggests that pharmacokinetics observed for the co-formulation will be well preserved in future translation to humans. Together these results suggest that the co-formulation has the potential to improve mealtime glucose management and reduce patient burden in the treatment of diabetes.

A co-formulation of supramolecularly stabilized insulin and pramlintide enhances mealtime glucagon suppression in diabetic pigs

Treatment of patients with diabetes with insulin and pramlintide (an amylin analogue) is more effective than treatment with insulin only. However, because mixtures of insulin and pramlintide are unstable and have to be injected separately, amylin analogues are only used by 1.5% of people with diabetes needing rapid-acting insulin. Here, we show that the supramolecular modification of insulin and pramlintide with cucurbit[7]uril-conjugated polyethylene glycol improves the pharmacokinetics of the dual-hormone therapy and enhances postprandial glucagon suppression in diabetic pigs. The co-formulation is stable for over 100 h at 37 °C under continuous agitation, whereas commercial formulations of insulin analogues aggregate after 10 h under similar conditions. In diabetic rats, the administration of the stabilized co-formulation increased the area-of-overlap ratio of the pharmacokinetic curves of pramlintide and insulin from 0.4 ± 0.2 to 0.7 ± 0.1 (mean ± s.d.) for the separate administration of the hormones. The co-administration of supramolecularly stabilized insulin and pramlintide better mimics the endogenous kinetics of co-secreted insulin and amylin, and holds promise as a dual-hormone replacement therapy.

Obesity in Type 1 Diabetes: Pathophysiology, Clinical Impact, and Mechanisms

There has been an alarming increase in the prevalence of obesity in people with type 1 diabetes in recent years. Although obesity has long been recognized as a major risk factor for the development of type 2 diabetes and a catalyst for complications, much less is known about the role of obesity in the initiation and pathogenesis of type 1 diabetes. Emerging evidence suggests that obesity contributes to insulin resistance, dyslipidemia, and cardiometabolic complications in type 1 diabetes. Unique therapeutic strategies may be required to address these comorbidities within the context of intensive insulin therapy, which promotes weight gain. There is an urgent need for clinical guidelines for the prevention and management of obesity in type 1 diabetes. The development of these recommendations will require a transdisciplinary research strategy addressing metabolism, molecular mechanisms, lifestyle, neuropsychology, and novel therapeutics. In this review, the prevalence, clinical impact, energy balance physiology, and potential mechanisms of obesity in type 1 diabetes are described, with a special focus on the substantial gaps in knowledge in this field. Our goal is to provide a framework for the evidence base needed to develop type 1 diabetes-specific weight management recommendations that account for the competing outcomes of glycemic control and weight management.

IAPP and type 1 diabetes: implications for immunity, metabolism and islet transplants

Islet amyloid polypeptide (IAPP), the main component of islet amyloid in type 2 diabetes and islet transplants, is now recognized as a contributor to beta cell dysfunction. Increasingly, evidence warrants its investigation in type 1 diabetes owing to both its immunomodulatory and metabolic actions. Autoreactive T cells to IAPP-derived epitopes have been described in humans, suggesting that IAPP is an islet autoantigen in type 1 diabetes. In addition, although aggregates of IAPP have not been implicated in type 1 diabetes, they are potent pro-inflammatory stimuli to innate immune cells, and thus, could influence autoimmunity. IAPP aggregates also occur rapidly in transplanted islets and likely contribute to islet transplant failure in type 1 diabetes through sterile inflammation. In addition, since type 1 diabetes is a disease of both insulin and IAPP deficiency, clinical trials have examined the potential benefits of IAPP replacement in type 1 diabetes with the injectable IAPP analogue, pramlintide. Pramlintide limits postprandial hyperglycemia by delaying gastric emptying and suppressing hyperglucagonemia, underlining the possible role of IAPP in postprandial glucose metabolism. Here, we review IAPP in the context of type 1 diabetes: from its potential involvement in type 1 diabetes pathogenesis, through its role in glucose metabolism and use of IAPP analogues as therapeutics, to its potential role in clinical islet transplant failure and considerations in this regard for future beta cell replacement strategies.

Adjuvant Liraglutide and Insulin Versus Insulin Monotherapy in the Closed-Loop System in Type 1 Diabetes: A Randomized Open-Labeled Crossover Design Trial

BACKGROUND

The closed-loop (CL) system delivers insulin in a glucose-responsive manner and optimal postprandial glycemic control is difficult to achieve with the algorithm and insulin available. We hypothesized that adjunctive therapy with liraglutide, a once-daily glucagon-like peptide-1 agonist, would be more effective in normalizing postprandial hyperglycemia versus insulin monotherapy in the CL system, in patients with type 1 diabetes.

METHODS

This was a randomized, controlled, open-label, crossover design trial comparing insulin monotherapy versus adjuvant subcutaneous liraglutide 1.2 mg and insulin, using the CL system in 15 patients. Blood glucose (BG), insulin, and glucagon concentrations were analyzed.

RESULTS

The liraglutide arm was associated with overall decreased mean BG levels (P = .0002). The average BG levels from 8:00 pm (day 1) to 9:00 pm (day 2) were lower in the liraglutide arm (144.6 ± 36.31 vs 159.7 ± 50.88 mg/dl respectively; P = .0002). Two-hour postbreakfast and lunch BG profiles were better in the liraglutide arm (P < .05) and the insulin and glucagon assay values were lower (P < .0001). Postprandially, the area under the curve (AUC) for 2-hour postbreakfast and lunch BG levels were significant (P = .01, P = .03) and the AUC for glucagon, postbreakfast (P < .0001) and lunch (P < .05), was also significant. The incidence of hypoglycemia did not differ between arms (P = .83, Fisher's exact test). Overall, adjunct liraglutide therapy plus CL was well tolerated even with expected side effects.

CONCLUSION

This is a proof-of-concept study showing liraglutide can be a potential adjunctive therapy in addition to CL with insulin to reduce postprandial hyperglycemia in type 1 diabetes.

Gastric Emptying Is More Rapid in Adolescents With Type 1 Diabetes and Impacts on Postprandial Glycemia

CONTEXT

Gastric emptying is a critical determinant of postprandial glycemic control in health and type 1 diabetes. There are few studies that assess the relationship between gastric emptying and postprandial glycaemia in adolescents with type 1 diabetes.

OBJECTIVE

The objectives of the study were to quantify gastric emptying in adolescents with type 1 diabetes and examine its relationship to postprandial glycaemia and autonomic function.

DESIGN

This was a case-control study. Gastric half-emptying time of a solid meal was measured by a (13)C-octanoate breath test. Cardio-autonomic function was measured by heart rate variability. Chronic and postprandial gastrointestinal symptoms were evaluated by questionnaire and visual analog scales. Blood glucose concentrations were monitored frequently during the study.

SETTING

The study was conducted at a tertiary pediatric hospital in South Australia.

PARTICIPANTS

Thirty adolescents (aged 15 ± 2.5 y) with type 1 diabetes and age- and sex-matched controls (gastric emptying, n = 20; heart rate variability, n = 135) participated in the study.

MAIN OUTCOME

Gastric half-emptying time was the main outcome in the study.

RESULTS

Gastric emptying was more rapid in subjects with type 1 diabetes than controls [median half emptying time 78 (interquartile range 61-99) vs 109 (interquartile range 71-124) min, P = .02]. The postprandial rise in blood glucose at 60 minutes was strongly related to gastric half-emptying time (R = -0.65, P = .0001). Gastric emptying was slower in subjects with fasting hyperglycemia but was not related to heart rate variability. Nausea, bloating, and anxiety were related to fasting glycemia (P = .03).

CONCLUSION

Rapid gastric emptying is a major determinant of postprandial glycemia in adolescents with type 1 diabetes. This observation has significant implications for therapy.

A model of glucose-insulin-pramlintide pharmacokinetics and pharmacodynamics in type I diabetes

Type 1 diabetes mellitus (T1DM) complications are significantly reduced when normoglycemic levels are maintained via intensive therapy. The artificial pancreas is designed for intensive glycemic control; however, large postprandial excursions after a meal result in poor glucose regulation. Pramlintide, a synthetic analog of the hormone amylin, reduces the severity of postprandial excursions by reducing appetite, suppressing glucagon release, and slowing the rate of gastric emptying. The goal of this study is to create a glucose-insulin-pramlintide physiological model that can be employed into a controller to improve current control approaches used in the artificial pancreas. A model of subcutaneous (SC) pramlintide pharmacokinetics (PK) was developed by revising an intravenous (IV) pramlintide PK model and adapting SC insulin PK from a glucose-insulin model. Gray-box modeling and least squares optimization were used to obtain parameter estimates. Pharmacodynamics (PD) were obtained by choosing parameters most applicable to pramlintide mechanisms and then testing using a proportional PD effect using least squares optimization. The model was fit and validated using 27 data sets, which included placebo, PK, and PD data. SC pramlintide PK root mean square error values range from 1.98 to 10.66 pmol/L. Pramlintide PD RMSE values range from 10.48 to 42.76 mg/dL. A new in silico model of the glucose-insulin-pramlintide regulatory system is presented. This model can be used as a platform to optimize dosing of both pramlintide and insulin as a combined therapy for glycemic regulation, and in the development of an artificial pancreas as the kernel for a model-based controller.

An update on the pharmacotherapy options for pediatric diabetes

INTRODUCTION

Diabetes mellitus is a frequent endocrine disease during childhood and adolescence. Achieving a good glycemic control is of paramount importance to avoid short- and long-term complications and to allow a normal growth and quality of life.

AREAS COVERED

This review offers an update on current available treatment strategies for type 1 and type 2 diabetes approved for use in children and adolescents.

EXPERT OPINION

Although many progresses have been made in the field of diabetes management in children and adolescents, there are still several problems to deal with. With regard to type 1 diabetes, insulin remains the main and essential therapeutic strategy. However, the main issue is to develop a system that allows more physiological insulin coverage and reduces the risk of hypoglycemia and weight gain. Adjunct therapies would be invaluable for patients struggling to achieve an acceptable glycemic control. Treatment of type 2 diabetes is based on lifestyle interventions and metformin is the first-line drug for children older than 10 years. As for type 1 diabetes, there is a strong need for developing new drugs to be used alone or in combination.

Effect of pramlintide on prandial glycemic excursions during closed-loop control in adolescents and young adults with type 1 diabetes

OBJECTIVE

Even under closed-loop (CL) conditions, meal-related blood glucose (BG) excursions frequently exceed target levels as a result of delays in absorption of insulin from the subcutaneous site of infusion. We hypothesized that delaying gastric emptying with preprandial injections of pramlintide would improve postprandial glycemia by allowing a better match between carbohydrate and insulin absorptions.

RESEARCH DESIGN AND METHODS

Eight subjects (4 female; age, 15-28 years; A1C, 7.5 ± 0.7%) were studied for 48 h on a CL insulin-delivery system with a proportional integral derivative algorithm with insulin feedback: 24 h on CL control alone (CL) and 24 h on CL control plus 30-μg premeal injections of pramlintide (CLP). Target glucose was set at 120 mg/dL; timing and contents of meals were identical on both study days. No premeal manual boluses were given. Differences in reference BG excursions, defined as the incremental glucose rise from premeal to peak, were compared between conditions for each meal.

RESULTS

CLP was associated with overall delayed time to peak BG (2.5 ± 0.9 vs. 1.5 ± 0.5 h; P < 0.0001) and reduced magnitude of glycemic excursion (88 ± 42 vs. 113 ± 32 mg/dL; P = 0.006) compared with CL alone. Pramlintide effects on glycemic excursions were particularly evident at lunch and dinner, in association with higher premeal insulin concentrations at those mealtimes.

CONCLUSIONS

Pramlintide delayed the time to peak postprandial BG and reduced the magnitude of prandial BG excursions. Beneficial effects of pramlintide on CL may in part be related to higher premeal insulin levels at lunch and dinner compared with breakfast.

Pramlintide and the treatment of diabetes: a review of the data since its introduction

INTRODUCTION

Postprandial glucose excursions negatively affect glycemic control and markers of cardiovascular health. Pramlintide, an amylinomimetic, is approved for treatment of elevated postprandial glucose levels in type 1 and type 2 diabetes mellitus.

AREAS COVERED

A literature search of PubMed was conducted to locate articles (up to January 2011) pertaining to original preclinical and clinical research and reviews of amylin and pramlintide. Additional sources were selected from reference lists within articles obtained through the original literature search and from the internet. This article describes the known effects of endogenous amylin and the pharmacodynamics, pharmacokinetics and clinical efficacy of pramlintide. Drug-drug interactions and safety and tolerability are also reviewed.

EXPERT OPINION

Pramlintide significantly reduces hemoglobin A(1c) and body weight in patients with type 1 and type 2 diabetes mellitus. Newer research is focusing on weight loss effects of pramlintide and pramlintide plus metreleptin in nondiabetic obese individuals. Preliminary results of these studies are discussed.

Physiologic insulin delivery with insulin feedback: a control systems perspective

Individuals with type 1 diabetes mellitus must effectively manage glycemia to avoid acute and chronic complications related to aberrations of glucose levels. Because optimal diabetes management can be difficult to achieve and burdensome, research into a closed-loop insulin delivery system has been of interest for several decades. This paper provides an overview, from a control systems perspective, of the research and development effort of a particular algorithm--the external physiologic insulin delivery system. In particular the introduction of insulin feedback, based on β-cell physiology, is covered in detail. A summary of human clinical trials is provided in the context of the evolution of this algorithm, and this paper outlines some of the research avenues that show particular promise.

The role of adjunctive exenatide therapy in pediatric type 1 diabetes

OBJECTIVE

Exenatide improves postprandial glycemic excursions in type 2 diabetes. Exenatide could benefit type 1 diabetes as well. We aimed to determine an effective and safe glucose-lowering adjuvant exenatide dose in adolescents with type 1 diabetes.

RESEARCH DESIGN AND METHODS

Eight subjects completed a three-part double-blinded randomized controlled study of premeal exenatide. Two doses of exenatide (1.25 and 2.5 microg) were compared with insulin monotherapy. Prandial insulin dose was reduced by 20%. Gastric emptying and hormones were analyzed for 300 min postmeal.

RESULTS

Treatment with both doses of exenatide versus insulin monotherapy significantly reduced glucose excursions over 300 min (P < 0.0001). Exenatide administration failed to suppress glucagon but delayed gastric emptying (P < 0.004).

CONCLUSIONS

Adjunctive exenatide therapy reduces postprandial hyperglycemia in adolescents with type 1 diabetes. This reduction in glucose excursion occurs despite reduction in insulin dose. We suggest that exenatide has therapeutic potential as adjunctive therapy in type 1 diabetes.

A pilot trial of pramlintide home usage in adolescents with type 1 diabetes

OBJECTIVE

The objective of this study was to evaluate the safety and efficacy of home pramlintide use in adolescents with type 1 diabetes.

PATIENTS AND METHODS

This was a randomized, 28-day pilot trial of pramlintide (maximum dose: 30 microg per meal) in 10 adolescents aged 13 to 17 years. End points included changes in hemoglobin A1c (HbA1c) values, body weight, and postprandial peak blood glucose levels and area under the curve on continuous glucose monitoring.

RESULTS

Changes in HbA1c values, body weight, and total insulin dose declined in the treatment group compared with the control group (bootstrapped, P <or= .02 for each). The treatment group also demonstrated lower average dinner area under the curve (P = .02) and lower maximum breakfast (P = .03) and dinner (P = .02) postprandial blood glucose values.

CONCLUSIONS

Pramlintide can help some adolescents to decrease postprandial hyperglycemia, HbA1c values, body weight, and insulin dosages. Additional large-scale trials should now be considered.

Pramlintide lowered glucose excursions and was well-tolerated in adolescents with type 1 diabetes: results from a randomized, single-blind, placebo-controlled, crossover study

OBJECTIVES

To evaluate the pharmacokinetics, pharmacodynamics, safety, and tolerability of pramlintide in treating adolescents with type 1 diabetes.

STUDY DESIGN

Twelve subjects (9 females, 3 males, age 12 to 17 years; A1C, 8.4%; body mass index, 25 kg/m(2)) were randomized to pramlintide (15 or 30 microg) or placebo administered before a standardized breakfast. Insulin lispro (50% of usual mealtime dose) was injected separately. Acetaminophen (1000 mg) was administered orally to provide an indicator of gastric emptying rate.

RESULTS

In 9 evaluable subjects, plasma pramlintide concentrations increased dose-proportionately; mean peak plasma concentration (C(max)) (15-microg dose, 93 +/- 9 pg/mL; 30-microg dose, 202 +/- 21 pg/mL) occurred approximately 0.3 h (median time to peak concentration) after administration. Pramlintide reduced incremental area under the concentration curve (AUC(0-3h)) for glucagon and glucose versus placebo (glucagon: 15-microg dose, 4 +/- 7 pg(*)h/mL; 30-microg dose, 5 +/- 7 pg(*)h/mL; placebo, 35 +/- 9 pg(*)h/mL; glucose: 15-microg dose, 129 +/- 43 mg(*)h/dL; 30-microg dose, 132 +/- 37 mg(*)h/dL; placebo, 217 +/- 56 mg(*)h/dL). Acetaminophen C(max) decreased with pramlintide; median T(max) was delayed by approximately 2.6- to 3.8-fold. Pramlintide was well tolerated, and no treatment-related adverse events occurred.

CONCLUSIONS

Pramlintide reduced postprandial glucagon and glucose excursions and slowed gastric emptying in adolescents with type 1 diabetes, with no treatment-related adverse events. Long-term studies evaluating the efficacy and safety of pramlintide in adolescents are warranted.

Reducing postprandial hyperglycemia with adjuvant premeal pramlintide and postmeal insulin in children with type 1 diabetes mellitus

OBJECTIVE

The purpose of this study was to determine the effect of adjuvant premeal pramlintide with postmeal insulin on postprandial hyperglycemia in children with type 1 diabetes mellitus (T1DM).

METHODS

Eight adolescents with T1DM on intensive insulin therapy participated in an open-label, non-randomized, crossover study, comparing postprandial glucose excursions in study A (prescribed insulin regimen and given premeal) vs. study B (pramlintide + insulin). Prandial insulin dose for study B was decreased by 20% and given postmeal, while pramlintide was given just before the meal. Blood glucose (BG), glucagon, and pramlintide concentrations were measured basally and at timed intervals during a 300-min study period.

RESULTS

Postprandial incremental BG for the duration of the study was reduced in study B vs. study A with AUC((-60 to 300 min)) (area under the curve) at 6600 +/- 2371 vs. 20 230 +/- 3126 mg/dL/min (367 +/- 132 vs. 1124 +/- 174 mmol/L/min) (p < 0.001). Glucagon concentration was suppressed for approximately 120 min following administration of 30 microg of pramlintide and postmeal insulin (p < 0.003). No severe hypoglycemic episodes were experienced in this study.

CONCLUSIONS

Postprandial hyperglycemia is considerably reduced in adolescents with T1DM when treated with fixed-dose premeal pramlintide, and precisely calculated postmeal insulin, without significant side effects.

Twenty-four-hour simultaneous subcutaneous Basal-bolus administration of insulin and amylin in adolescents with type 1 diabetes decreases postprandial hyperglycemia

CONTEXT

The purpose of this study was to examine the effect of continuous sc replacement of amylin and insulin for a 24-h period on glucose homeostasis in adolescents with type 1diabetes.

METHODS

Thirteen adolescents with type 1 diabetes on insulin pump therapy participated in a randomized, controlled, crossover design study comparing continuous sc insulin monotherapy (part A) vs. continuous sc insulin and pramlintide infusion (part B). In part A, basal and bolus insulin infusion was per prescribed home regimen. In part B, the basal insulin infusion was the same as part A, but prandial insulin boluses were reduced by 20%. Basal and prandial bolus pramlintide were administered simultaneously via another pump. All boluses were given as a dual wave.

RESULTS

The study regimen resulted in a 26% reduction in postprandial hyperglycemia as compared to insulin monotherapy (area under the curve, 600 min, 2610 +/- 539 vs. 692 +/- 861 mg/liter . min) (P < 0.008). Glucagon concentrations were suppressed postprandially (P < 0.003) but not in the postabsorptive state, whereas plasma insulin concentrations were unchanged.

CONCLUSIONS

Simultaneous continuous sc pramlintide and insulin infusion has the potential of improving glucose concentrations by way of physiological replacement.

New potential adjuncts to treatment of children with type 1 diabetes mellitus

Insulin administration is the primary therapy for type 1 diabetes mellitus (T1DM). Current available insulin therapies do not successfully enable children with T1DM to reach glycemic goals without side effects such as hypoglycemia and weight gain. Pramlintide is a synthetic analog of human amylin that acts in conjunction with insulin to delay gastric emptying and inhibit the release of glucagon and is indicated for use in patients with type 1 and type 2 diabetes. Recent studies in adult patients have examined the role of glucagon-like peptide 1 (GLP-1) and agents that bind to its receptor in type 1 diabetes. It is hypothesized that a major component of the glycemic effect is attributable to the known action of GLP-1 to delay gastric emptying and to inhibit glucagon secretion. Further studies with the use of amylin analogs and long-acting GLP-1 agonists as congeners with insulin in T1DM are indicated in children. In recent years, our better understanding of the pathophysiology of diabetes has led to the development of new therapies for diabetes. This article reviews the potential use of these newer pharmacologic agents as adjunctive therapy in T1DM in children and adolescents.

Gastric emptying and postprandial glucose excursions in adolescents with type 1 diabetes

Because amylin is co-secreted with insulin from beta cells, patients with type 1 diabetes (T1DM) are deficient in both insulin and amylin. Amylin delays gastric emptying and suppresses glucagon in the postprandial period. Hence, we hypothesized that children with complication-naive T1DM have accelerated gastric emptying in response to a mixed meal because of amylin deficiency. Amylin, glucagon, insulin, glucose, and gastric emptying were measured in seven T1DM and in eight control subjects without diabetes. Subjects with T1DM had markedly elevated glucose concentrations when compared with controls (p < 0.0001). Amylin concentrations as predicted were lower in T1DM compared with those in controls (p < 0.0001). Insulin did not peak in the immediate postprandial period in T1DM when compared with controls (p < 0.0001). Glucagon concentrations did not significantly differ between groups. Interestingly, gastric velocity was delayed in patients with T1DM compared with controls (p < 0.01). In conclusion, subjects with T1DM do have amylin deficiency but this is not associated with accelerated gastric emptying as we had hypothesized but rather with delayed gastric emptying. Factors other than amylin play a role in control of gastric motility in T1DM. Subcutaneous insulin delivery fails to reach adequate concentrations in the postprandial period to curtail peak glucose concentration in T1DM.