Prandial glucose regulation in the glucose triad: emerging evidence and insights

Assessing Time in Range with Postprandial Glucose-Focused Titration of Ultra Rapid Lispro (URLi) in People with Type 1 Diabetes

INTRODUCTION

To assess time in range (TIR) (70-180 mg/dL) with postprandial glucose (PPG)-focused titration of ultra rapid lispro (URLi; Lyumjev®) in combination with insulin degludec in people with type 1 diabetes (T1D).

METHODS

This phase 2, single-group, open-label, exploratory study was conducted in 31 participants with T1D on multiple daily injection therapy. Participants were treated with insulin degludec and Lispro for an 11-day lead-in and then URLi for a 46-day treatment period consisting of 35-day titration and 11-day endpoint maintenance period. Glucose targets for the titration period were PPG < 140 mg/dL or < 20% increase from premeal, fasting glucose 80-110 mg/dL, and overnight excursion ± 30 mg/dL or less. Participants used the InPen™ bolus calculator and Dexcom G6 continuous glucose monitoring (CGM).

RESULTS

Primary endpoint mean TIR (70-180 mg/dL) with URLi during the maintenance period was 70.2%. TIR (70-180 mg/dL) and times below/above range were not significantly different with URLi (maintenance) versus lispro (lead-in). HbA1c decreased from 7.1% at screening to 6.8% at endpoint (least squares mean [LSM] change from baseline, - 0.36%; P < 0.001). Fructosamine and 1,5-anhydroglucitol improved (P < 0.001). Mean hourly glucose using CGM was reduced from 8:00 AM to 4:00 PM with URLi. Overall highest PPG excursion across meals was significantly reduced at URLi endpoint compared with lispro lead-in (mean 56.5 vs 72.4 mg/dL; P < 0.001). Insulin-to-carbohydrate ratio (U/X g) was reduced (more insulin given) at breakfast at URLi endpoint vs lead-in (LSM 9.0 vs 9.7 g; P = 0.002) and numerically decreased at other meals. Total daily insulin dose (TDD) was higher at URLi endpoint compared with lispro lead-in (mean 50.2 vs 47.0 U; P = 0.046) with similar prandial/TDD ratio (mean 52.1% vs 51.2%). There were no severe hypoglycemia events during the study.

CONCLUSIONS

URLi in a basal-bolus regimen focusing on PPG targets demonstrated improved overall glycemic control and reduced PPG excursions without increased hypoglycemia in participants with T1D.

TRIAL REGISTRATION

ClinicalTrial.gov, NCT04585776.

Historical aspects of diagnosis and control of diabetes mellitus

Diabetes mellitus is a group of metabolic diseases affecting carbohydrate, lipid, and protein metabolism. This pathology has a long history, and it was considered a disease of the kidneys until the middle of the 19th century. Descriptions have been found in Egyptian papyri, in ancient Indian and Chinese medical literature, in the writings of ancient Greek and Arab doctors. Aretaeus of Cappadocia gave the first accurate description of the disease, coining the term diabetes. Thomas Willis first differentiated diabetes from other causes of polyuria by the sweet taste of urine. Matthew Dobson proved the presence of glucose in urine by evaporation. Claude Bernard demonstrated that hyperglycemia contributes to glucosuria. This is how the concept of the renal threshold appeared. In domestic practice, the term "renal threshold" was introduced by endocrinologist V.G. Baranov. The development of qualitative tests for determining glucose in the urine, the creation of test strips and glucometers has significantly improved the quality of life of patients with diabetes. The current stage of development of glucometry includes the determination of fasting plasma glucose, postprandial glycemia, glycated hemoglobin, as well as continuous glucose monitoring. Continuous glucose monitoring systems make it possible to estimate the time in target range, show the rate of rise or fall of glucose levels. It affects the rate and degree of carbohydrate metabolism compensation and allows for maximum control of the disease.

Effect of Consumption of Whole-Wheat Breads on FBS, HbA1c, and Blood Lipids in Patients with Type 2 Diabetes

Whole-wheat can have positive effect on blood parameters, such as blood sugar and fat profiles, in patients with diabetic. The aim of this study was to assess the effect of whole-wheat breads on hemoglobin A1c (HbA1c) and blood lipids in patients with type 2 diabetes (T2D). The study population included men and women with T2D aged 30 years old and over in Arak, Iran. Using random sampling method, 60 patients with T2D were selected and randomly divided into control and intervention groups. After taking blood samples from the patients, the intervention group was administered 180 g of wholegrain wheat for 12 weeks. The participants were asked not to change their diets and amounts of physical activity during the study period. After 12 weeks, blood samples were taken and insulin resistance indexes, blood glucose levels, and lipid profiles were examined. The results indicated that consumption of whole-wheat bread for 12 weeks can significantly reduce body weight, and HbA1c, triglyceride, total cholesterol, and low density lipoprotein cholesterol (LDL-c) levels, and increase high density lipoprotein cholesterol (HDL-c) levels (P<0.05). However, in the control group, changes in body weight, body mass index, HbA1c, total cholesterol, HDL-c, and LDL-c levels did not significantly differ before and after the intervention period (P>0.05). As consumption of whole-wheat bread has positive effects on control of various physical and biochemical indictors in patients with diabetes, its consumption should be included in educational programs at health centers across the country.

The effect of a split portion of flaxseed on 24-h blood glucose response

Purpose

Flaxseed can be effective at lowering and stabilising blood glucose responses. The aim of this study was to determine whether flaxseed could lower blood glucose response more effectively when consumed as a single portion of 30 g, or a split portion consumed three times per day (10 g flaxseed per portion).

Methods

The study was a randomised, repeated measures, cross-over design. Fifteen healthy participants consumed either (1) three flaxseed muffins containing a total of 30 g of flaxseed once in the morning, (2) three flaxseed muffins consumed at three different timepoints across the day (10 g flaxseed per muffin) or (3) three control muffins consumed at three different timepoints across the day (0 g flaxseed). The 24-h blood glucose response was measured using a continuous glucose monitor.

Results

The results of this study demonstrated that flaxseed muffins given three times a day were effective at lowering and maintaining blood glucose levels over 24 h, compared to the control muffins and that both flaxseed treatments resulting in a lower blood glucose iAUC during the night.

Conclusion

The results of this study indicated that adding flaxseed to a daily diet produced a lower glucose profile over 24 h in a free-living context compared to the control muffins.

Methylglyoxal, a Highly Reactive Dicarbonyl Compound, in Diabetes, Its Vascular Complications, and Other Age-Related Diseases

The formation and accumulation of methylglyoxal (MGO), a highly reactive dicarbonyl compound, has been implicated in the pathogenesis of type 2 diabetes, vascular complications of diabetes, and several other age-related chronic inflammatory diseases such as cardiovascular disease, cancer, and disorders of the central nervous system. MGO is mainly formed as a byproduct of glycolysis and, under physiological circumstances, detoxified by the glyoxalase system. MGO is the major precursor of nonenzymatic glycation of proteins and DNA, subsequently leading to the formation of advanced glycation end products (AGEs). MGO and MGO-derived AGEs can impact on organs and tissues affecting their functions and structure. In this review we summarize the formation of MGO, the detoxification of MGO by the glyoxalase system, and the biochemical pathways through which MGO is linked to the development of diabetes, vascular complications of diabetes, and other age-related diseases. Although interventions to treat MGO-associated complications are not yet available in the clinical setting, several strategies to lower MGO have been developed over the years. We will summarize several new directions to target MGO stress including glyoxalase inducers and MGO scavengers. Targeting MGO burden may provide new therapeutic applications to mitigate diseases in which MGO plays a crucial role.

Importance of Postprandial Glucose in Relation to A1C and Cardiovascular Disease

IN BRIEF This article reviews the evidence regarding the impact of postprandial glucose (PPG) on overall A1C and its relation to cardiovascular disease (CVD). To date, four randomized, controlled trials have evaluated the impact of PPG reduction on CVD; however, only one of these successfully demonstrated a positive effect. Despite this, epidemiological evidence does indicate a cardiovascular benefit of PPG reduction, and agents that can be used to manage PPG in people with type 2 diabetes are also discussed.

Expert Opinion: Patient Selection for Premixed Insulin Formulations in Diabetes Care

Premixed insulins are an important tool for glycemic control in persons with diabetes. Equally important in diabetes care is the selection of the most appropriate insulin regimen for a particular individual at a specific time. Currently, the choice of insulin regimens for initiation or intensification of therapy is a subjective decision. In this article, we share insights, which will help in rational and objective selection of premixed formulations for initiation and intensification of insulin therapy. The glycemic status and its variations in a person help to identify the most appropriate insulin regimen and formulation for him or her. The evolution of objective glucometric indices has enabled better glycemic monitoring of individuals with diabetes. Management of diabetes has evolved from a 'glucocentric' approach to a 'patient-centered' approach; patient characteristics, needs, and preferences should be evaluated when considering premixed insulin for treatment of diabetes.Funding: Novo Nordisk, India.

The role of methylglyoxal and the glyoxalase system in diabetes and other age-related diseases

The formation and accumulation of advanced glycation endproducts (AGEs) are related to diabetes and other age-related diseases. Methylglyoxal (MGO), a highly reactive dicarbonyl compound, is the major precursor in the formation of AGEs. MGO is mainly formed as a byproduct of glycolysis. Under physiological circumstances, MGO is detoxified by the glyoxalase system into D-lactate, with glyoxalase I (GLO1) as the key enzyme in the anti-glycation defence. New insights indicate that increased levels of MGO and the major MGO-derived AGE, methylglyoxal-derived hydroimidazolone 1 (MG-H1), and dysfunctioning of the glyoxalase system are linked to several age-related health problems, such as diabetes, cardiovascular disease, cancer and disorders of the central nervous system. The present review summarizes the mechanisms through which MGO is formed, its detoxification by the glyoxalase system and its effect on biochemical pathways in relation to the development of age-related diseases. Although several scavengers of MGO have been developed over the years, therapies to treat MGO-associated complications are not yet available for application in clinical practice. Small bioactive inducers of GLO1 can potentially form the basis for new treatment strategies for age-related disorders in which MGO plays a pivotal role.

Post-Glucose Load Plasma α-Dicarbonyl Concentrations Are Increased in Individuals With Impaired Glucose Metabolism and Type 2 Diabetes: The CODAM Study

OBJECTIVE

There is increasing evidence that postprandial glucose excursions play an important role in the development of vascular complications. The underlying mechanism is unknown, but glucose-derived formation of reactive α-dicarbonyl compounds may explain why acute hyperglycemia leads to increased risk for diabetes complications. In the current study, we investigated whether α-dicarbonyls are increased after a glucose load in individuals without or with impaired glucose metabolism (IGM) and type 2 diabetes.

RESEARCH DESIGN AND METHODS

Cross-sectional, linear analyses were performed in the Cohort on Diabetes and Atherosclerosis Maastricht (CODAM [n = 574, 61% men, 60 years old]) study. Individuals with normal glucose metabolism (n = 279), IGM (n = 120), and type 2 diabetes (n = 92) who had complete data on an oral glucose tolerance test (OGTT) and were not on insulin treatment were included in the study population. Plasma α-dicarbonyl (methylglyoxal [MGO], glyoxal [GO], and 3-deoxyglucosone [3-DG]) levels were measured in the fasting state and in samples of the OGTT by ultra-performance liquid chromatography-tandem mass spectrometry.

RESULTS

The presence of both IGM and type 2 diabetes was significantly associated with higher α-dicarbonyl incremental areas under the curve (iAUCs), as calculated from the OGTT (for IGM, MGO β = 0.190 [95% CI 0.106-0.274], GO β = 0.287 [95% CI 0.172-0.401], and 3-DG β = 0.285 [95% CI 0.221-0.349]; for type 2 diabetes, MGO β = 0.293 [95% CI 0.180-0.405], GO β = 0.536 [95% CI 0.382-0.689], and 3-DG β = 0.542 [95% CI 0.456-0.628]). Adjustment for glucose iAUC attenuated these associations. iAUCs of the α-dicarbonyls correlated highly with glucose iAUC but not with fasting glucose levels or HbA1c.

CONCLUSIONS

The increased levels of α-dicarbonyls during an OGTT in individuals with IGM and type 2 diabetes underline the potential importance of α-dicarbonyl stress as a candidate to explain the increased risk of diabetes complications in individuals with postprandial hyperglycemia.

Resistant starch and pullulan reduce postprandial glucose, insulin, and GLP-1, but have no effect on satiety in healthy humans

The aim of this study was to determine the effects of three novel fibers on satiety and serum parameters. In a randomized, double-blind, crossover design, fasted subjects (n=20) consumed a low-fiber control breakfast or one of four breakfasts containing 25 g of fiber from soluble corn fiber (SCF) or resistant starch (RS), alone or in combination with pullulan (SCF+P and RS+P). Visual analog scales assessed appetite, and blood samples were collected to measure glucose, insulin, ghrelin, and glucagon-like peptide-1 (GLP-1). The fiber treatments did not influence satiety or energy intake compared to control. RS+P significantly reduced glucose, insulin, and GLP-1, but neither SCF treatment differed from control. To conclude, these fibers have little impact on satiety when provided as a mixed meal matched for calories and macronutrients. Additional research regarding the physiological effects of these novel fibers is needed to guide their use as functional ingredients in food products.

Phloridzin reduces blood glucose levels and improves lipids metabolism in streptozotocin-induced diabetic rats

Phloridzin is the specific and competitive inhibition of sodium/glucose cotransporters in the intestine (SGLT1) and kidney (SGLT2). This property which could be useful in the management of postprandial hyperglycemia in diabetes and related disorders. Phloridzin is one of the dihydrochalcones typically contained in apples and in apple-derived products. The effect of phloridzin orally doses 5, 10, 20 and 40 mg/kg body weight on diabetes was tested in a streptozotocin-induced rat model of diabetes type 1. From beneficial effect of this compound is significant reduction of blood glucose levels and improve dyslipidemia in diabetic rats. As a well-known consequence of becoming diabetic, urine volume and water intake were significantly increased. Administration of phloridzin reduced urine volume and water intake in a dose-dependent manner. Phloretin decreases of food consumption, as well as a marked lowering in the weight. In conclusion, this compound could be proposed as an antihyperglycemic and antihyperlipidemic agent in diabetes and potential therapeutic in obesity.

Effects of the Soluble Fiber Complex PolyGlycopleX on Glucose Homeostasis and Body Weight in Young Zucker Diabetic Rats

Dietary fiber can reduce insulin resistance, body weight, and hyperlipidemia depending on fiber type, water solubility, and viscosity. PolyGlycopleX(®) (PGX(®)) is a natural, novel water soluble, non-starch polysaccharide complex that with water forms a highly viscous gel compared to other naturally occurring dietary fiber. We determined the effect of dietary PGX(®) vs. cellulose and inulin on the early development of insulin resistance, body weight, hyperlipidemia, and glycemia-induced tissue damage in young Zucker diabetic rats (ZDFs) in fasted and non-fasted states. ZDFs (5 weeks old) were fed a diet containing 5% (wgt/wgt) cellulose, inulin, or PGX(®) for 8 weeks. Body weight, lipids, insulin, and glucose levels were determined throughout the study and homeostasis model assessment (HOMA) was used to measure insulin sensitivity throughout the study in fasted animals. At study termination, insulin sensitivity (oral glucose tolerance test, OGTT) and kidney, liver, and pancreatic histopathology were determined. Body weight and food intake were significantly reduced by PGX(®) vs. inulin and cellulose. Serum insulin in fasted and non-fasted states was significantly reduced by PGX(®) as was non-fasted blood glucose. Insulin resistance, measured as a HOMA score, was significantly reduced by PGX(®) in weeks 5 through 8 as well as terminal OGTT scores in fed and fasted states. Serum total cholesterol was also significantly reduced by PGX(®). PGX(®) significantly reduced histological kidney and hepatic damage in addition to reduced hepatic steatosis and cholestasis. A greater mass of pancreatic β-cells was found in the PGX(®) group. PGX(®) therefore may be a useful dietary additive in the control of the development of the early development of the metabolic syndrome.

Effect of adding the novel fiber, PGX®, to commonly consumed foods on glycemic response, glycemic index and GRIP: a simple and effective strategy for reducing post prandial blood glucose levels--a randomized, controlled trial

BACKGROUND

Reductions in postprandial glycemia have been demonstrated previously with the addition of the novel viscous polysaccharide (NVP), PolyGlycopleX® (PGX®), to an OGTT or white bread. This study explores whether these reductions are sustained when NVP is added to a range of commonly consumed foods or incorporated into a breakfast cereal.

METHODS

Ten healthy subjects (4M, 6F; age 37.3 ± 3.6 y; BMI 23.8 ± 1.3 kg/m2), participated in an acute, randomized controlled trial. The glycemic response to cornflakes, rice, yogurt, and a frozen dinner with and without 5 g of NVP sprinkled onto the food was determined. In addition, 3 granolas with different levels of NVP and 3 control white breads and one white bread and milk were also consumed. All meals contained 50 g of available carbohydrate. Capillary blood samples were taken fasting and at 15, 30, 45, 60, 90 and 120 min after the start of the meal. The glycemic index (GI) and the glycemic reduction index potential (GRIP) were calculated. The blood glucose concentrations at each time and the iAUC values were subjected to repeated-measures analysis of variance (ANOVA) examining for the effect of test meal. After demonstration of significant heterogeneity, differences between individual means was assessed using GLM ANOVA with Tukey test to adjust for multiple comparisons.

RESULTS

Addition of NVP reduced blood glucose response irrespective of food or dose (p < 0.01). The GI of cornflakes, cornflakes+NVP, rice, rice+NVP, yogurt, yogurt+NVP, turkey dinner, and turkey dinner+NVP were 83 ± 8, 58 ± 7, 82 ± 8, 45 ± 4, 44 ± 4, 38 ± 3, 55 ± 5 and 41 ± 4, respectively. The GI of the control granola, and granolas with 2.5 and 5 g of NVP were 64 ± 6, 33 ± 5, and 22 ± 3 respectively. GRIP was 6.8 ± 0.9 units per/g of NVP.

CONCLUSION

Sprinkling or incorporation of NVP into a variety of different foods is highly effective in reducing postprandial glycemia and lowering the GI of a food.

CLINICAL TRIAL REGISTRATION

NCT00935350.

Gastric emptying, diabetes, and aging

Gastric emptying is mildly slowed in healthy aging, although generally remains within the normal range for young people. The significance of this is unclear, but may potentially influence the absorption of certain drugs, especially when a rapid effect is desired. Type 2 diabetes is common in the elderly, but there is little data regarding its natural history, prognosis, and management. This article focuses on the interactions between gastric emptying and diabetes, how each is influenced by the process of aging, and the implications for patient management.

Dietary carbohydrate intake and high-sensitivity C-reactive protein in at-risk women and men

BACKGROUND

The quality and quantity of dietary carbohydrate intake, measured as dietary glycemic load (GL), are associated with a number of cardiovascular disease (CVD) risk factors and, in healthy young women, are related to increased high-sensitivity C-reactive protein (hsCRP) concentrations. Our objective was to determine if GL is related to hsCRP and other measures of CVD risk in a population of sedentary, overweight, dyslipidemic middle-aged women and men enrolled in an exercise intervention trial (STRRIDE).

METHODS

This was a cross-sectional evaluation of the relationships between measures of dietary carbohydrate intake, calculated from food frequency questionnaire data, and CVD risk factors, including plasma hsCRP, measured in 171 subjects.

RESULTS

After adjusting for energy intake, GL and other measures of carbohydrate intake were not independently related to hsCRP (P > .05 for all). In the analyses performed separately for each sex, only the quantity of carbohydrate intake was independently related to hsCRP (R2 = 0.28, P < .04), and this relationship was present for women but not for men. The strongest relationship identified between GL and any CVD risk factor was for cardiorespiratory fitness (R2 = 0.12, P < .02); an elevated GL was associated with a lower level of fitness in all subjects, and this relationship persisted even when the findings were adjusted for energy intake and sex (R2 = 0.48, P < .03).

CONCLUSIONS

In middle-aged, sedentary, overweight to mildly obese, dyslipidemic individuals, consuming a diet with a low GL is associated with better cardiorespiratory fitness. Our findings suggest that the current literature relating carbohydrate intake and hsCRP should be viewed with skepticism, especially in the extension to at-risk populations that include men.

The incretin mimetic exenatide as a monotherapy in patients with type 2 diabetes

BACKGROUND

Exenatide is an adjunctive therapy for type 2 diabetes, and preliminary evidence suggests that its glucoregulatory effects may be similar in the absence of oral therapy.

METHODS

Study A was a randomized, double-blind, placebo-controlled study of 99 patients with type 2 diabetes that received either 10 microg twice-daily, 10 microg once-daily, or 20 microg once-daily exenatide or placebo for 28 days in the absence of background pharmacotherapy. Study B was an open-label extension of a short-term study of 127 patients with type 2 diabetes treated with metformin or diet and exercise. Patients received exenatide 5 microg twice-daily for 4 weeks followed by 10 microg for 26 weeks. Subjects treated with metformin continued oral therapy.

RESULTS

Monotherapeutic treatment with 10 microg of exenatide twice-daily for 28 days resulted in significant mean reductions in glycosylated hemoglobin (A1C) of -0.4 +/- 0.1% and fasting plasma glucose of -36.1 +/- 11.0 mg/dL compared to increases of +0.2 +/- 0.1% and +11.0 +/- 12.7 mg/dL with placebo. Self-monitored blood glucose profiles showed significant mean reductions in daily blood glucose concentrations in exenatide-treated patients compared to placebo. Exenatide treatment for 30 weeks in an open-label extension study resulted in similar mean reductions from baseline in A1C and body weight in patients treated with diet and exercise alone (-1.0 +/- 0.2% and -4.3 +/- 1.3 kg, respectively) as those treated on a background of metformin (-0.9 +/- 0.1% and -3.7 +/- 0.5 kg, respectively). In both studies, the most frequent adverse events were gastrointestinal and predominantly mild to moderate in intensity. Incidence of mild-to-moderate hypoglycemia was low, with no severe hypoglycemia.

CONCLUSIONS

Exenatide twice-daily monotherapy resulted in glycemic improvements and reductions in body weight comparable to that of exenatide combination therapy with metformin in patients with type 2 diabetes.

Pathophysiology and management of diabetic gastropathy: a guide for endocrinologists

Delayed gastric emptying is frequently observed in patients with long-standing type 1 and type 2 diabetes mellitus, and potentially impacts on upper gastrointestinal symptoms, glycaemic control, nutrition and oral drug absorption. The pathogenesis remains unclear and management strategies are currently suboptimal. Therapeutic strategies focus on accelerating gastric emptying, controlling symptoms and improving glycaemic control. The potential adverse effects of hyperglycaemia on gastric emptying and upper gut symptoms indicate the importance of normalising blood glucose if possible. Nutritional and psychological supports are also important, but often neglected. A number of recent pharmacological and non-pharmacological therapies show promise, including gastric electrical stimulation. As with all chronic illnesses, a multidisciplinary approach to management is recommended, but there are few data regarding long-term outcomes.