Differential effects of GLP-1 receptor agonists on components of dysglycaemia in individuals with type 2 diabetes mellitus

Effects on weight loss and glycemic control with SAR441255, a potent unimolecular peptide GLP-1/GIP/GCG receptor triagonist

Unimolecular triple incretins, combining the activity of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and glucagon (GCG), have demonstrated reduction in body weight and improved glucose control in rodent models. We developed SAR441255, a synthetic peptide agonist of the GLP-1, GCG, and GIP receptors, structurally based on the exendin-4 sequence. SAR441255 displays high potency with balanced activation of all three target receptors. In animal models, metabolic outcomes were superior to results with a dual GLP-1/GCG receptor agonist. Preclinical in vivo positron emission tomography imaging demonstrated SAR441255 binding to GLP-1 and GCG receptors. In healthy subjects, SAR441255 improved glycemic control during a mixed-meal tolerance test and impacted biomarkers for GCG and GIP receptor activation. Single doses of SAR441255 were well tolerated. The results demonstrate that integrating GIP activity into dual GLP-1 and GCG receptor agonism provides improved effects on weight loss and glycemic control while buffering the diabetogenic risk of chronic GCG receptor agonism.

Glycaemic variabilities: Key questions in pursuit of clarity

After years of intensive investigation, the definition of glycaemic variability remains unclear and the term variability in glucose homoeostasis might be more appropriate covering both short and long-term glycaemic variability. For the latter, we remain in the search of an accurate definition and related targets. Recent work leads us to consider that the within-subject variability of HbA1c calculated from consecutive determinations of HbA1c at regular time-intervals could be the most relevant index for assessing the long-term variability with a threshold value of 5% (%CV = SD of HbA1c/mean HbA1c) to separate stability from lability of HbA1c. Presently, no one can deny that short- and long-term glucose variability should be maintained within their lower ranges to limit the incidence of hypoglycaemia. Usually, therapeutic strategies aimed at reducing post-meal glucose excursions, i.e. the major contributor to daily glucose fluctuations, exert a beneficial effect on the short-term glucose variability. This explains the effectiveness of adjunct therapies with either GLP- receptor agonists or SGLT inhibitors in type 2 diabetes. In type 1 diabetes, the application of a CGM device alone reduces the short-term glycaemic variability. In contrast, sophisticated insulin delivery does not necessarily lead to such reductions despite marked downward shifts of 24-hour glycaemic profiles. Such contrasting observations raise the question as to whether the prolonged wear of CGM devices is or not the major causative factor for improvement in glucose variability among intensively insulin-treated persons with type 1 diabetes.

The Benefit of Insulin Degludec/Liraglutide (IDegLira) Compared With Basal-Bolus Insulin Therapy is Consistent Across Participant Subgroups With Type 2 Diabetes in the DUAL VII Randomized Trial

BACKGROUND

Insulin degludec/liraglutide (IDegLira) results in glycated hemoglobin (HbA1c) levels comparable with basal-bolus (BB) therapy. Here, we assessed the effect of once-daily IDegLira compared with BB (once-daily insulin glargine 100 U/mL and insulin aspart ≤4 times/day) across subgroups with varying characteristics.

MATERIALS AND METHODS

DUAL VII trial participants (type 2 diabetes [T2D], HbA1c 53-86 mmol/mol [7.0%-10.0%]) were subgrouped post hoc based on the following baseline characteristics: HbA1c (≤58.5, >58.5 to ≤69.4, and >69.4 mmol/mol; ≤7.5%, >7.5 to ≤8.5%, and >8.5%), body mass index (<30, ≥30 to <35, and ≥35 kg/m²), age (18 to <65 and ≥65 years), duration of diabetes (≥0 to 10 and ≥10 years), total pretrial daily basal insulin dose (20 to <30, ≥30 to <40, and ≥40 to ≤50 U), and fasting plasma glucose (<7.2 mmol/L/<130 mg/dL and ≥7.2 mmol/L/≥130 mg/dL).

RESULTS

Compared with BB, and in all subgroups, IDegLira treatment consistently gave similar HbA1c reductions, less severe or blood glucose-confirmed hypoglycemia, lower end-of-trial (EOT) total daily insulin dose, and weight loss. In all subgroups, mean EOT HbA1c was ≤53 mmol/mol (≤7.0%). The greatest HbA1c reduction occurred in the highest baseline HbA1c subgroup. Overall, mean EOT daily insulin dose was 0.43 to 0.52 U/kg with IDegLira and 0.74 to 1.07 U/kg with BB. More participants achieved the triple composite endpoint (HbA1c <53 mmol/mol [<7.0%] without weight gain or hypoglycemia) with IDegLira vs BB across the baseline HbA1c subgroups (≤58.5 mmol/mol [44.6% vs 7.0%], >58.5 to ≤69.4 mmol/mol [41.1% vs 8.3%], and >69.4 mmol/mol [23.8% vs 3.4%]).

CONCLUSION

These results support initiating IDegLira in patients with varying baseline characteristics and uncontrolled T2D on basal insulin.

CLINICALTRIALS.GOV REGISTRATION

NCT02420262.

High protein diet leads to prediabetes remission and positive changes in incretins and cardiovascular risk factors

BACKGROUND AND AIMS

High Protein diets may be associated with endocrine responses that favor improved metabolic outcomes. We studied the response to High Protein (HP) versus High Carbohydrate (HC) Diets in terms of incretin hormones GLP-1 and GIP, the hunger hormone ghrelin and BNP, which is associated with cardiac function. We hypothesized that HP diets induce more pronounced release of glucose lowering hormones, suppress hunger and improve cardiac function.

METHODS AND RESULTS

24 obese women and men with prediabetes were recruited and randomized to either a High Protein (HP) (n = 12) or High Carbohydrate (HC) (n = 12) diet for 6 months with all food provided. OGTT and MTT were performed and GLP-1, GIP, Ghrelin, BNP, insulin and glucose were measured at baseline and 6 months on the respective diets. Our studies showed that subjects on the HP diet had 100% remission of prediabetes compared to only 33% on the HC diet with similar weight loss. HP diet subjects had a greater increase in (1) OGTT GLP-1 AUC(p = 0.001) and MTT GLP-1 AUC(p = 0.001), (2) OGTT GIP AUC(p = 0.005) and MTT GIP AUC(p = 0.005), and a greater decrease in OGTT ghrelin AUC(p = 0.005) and MTT ghrelin AUC(p = 0.001) and BNP(p = 0.001) compared to the HC diet at 6 months.

CONCLUSIONS

This study demonstrates that the HP diet increases GLP-1 and GIP which may be responsible in part for improved insulin sensitivity and β cell function compared to the HC diet. HP ghrelin results demonstrate the HP diet can reduce hunger more effectively than the HC diet. BNP and other CVRF, metabolic parameters and oxidative stress are significantly improved compared to the HC diet. CLINICALTRIALS.

GOV IDENTIFIER

NCT01642849.

Efficacy and safety of exenatide as add-on therapy for patients with type 2 diabetes with an intensive insulin regimen: A randomized double-blind trial

AIM

To assess the safety and efficacy of the short-acting glucagon-like peptide-1 receptor agonist exenatide on a population of patients with type 2 diabetes (T2D) mostly treated with continuous subcutaneous insulin injection (CSII).

MATERIALS AND METHODS

A phase 2/3, multicentre, randomized, parallel-group, double-blind, placebo-controlled, 6-month trial was conducted. Patients were randomized to receive subcutaneous (SC) injections of exenatide (10 μg BID) or matched placebo.

RESULTS

A total of 46 patients with T2D and elevated HbA1c were randomized (42% of the planned sample size): exenatide (n = 28) and placebo (n = 18). CSII treatment was used by 75% and 89% of patients of the exenatide and placebo groups, respectively. At 6 months, the change in HbA1c was -0.62% ± 0.94% and 0.08% ± 0.81% in the exenatide and placebo groups, respectively (difference, -0.70%; 95% CI [-1.24%; -0.15%], P = .014); body weight and body mass index decreased in the exenatide group (-2.55 ± 3.25 kg and -1.00 ± 1.31 kg/m² ) and increased in the placebo group (1.29 ± 2.82 kg and 0.46 ± 1.16 kg/m² ) (observed difference, -3.85 and -1.45, respectively, both P < .001); the postdinner capillary blood glucose value was lower in the exenatide group compared with the placebo group (162.4 ± 80.5 vs. 259.1 ± 94.4 mg/dL, respectively; observed difference, -96.7, P < .01). Hypoglycaemic risk, quality of life and overall safety were not different between the groups, apart from the expected occurrence of digestive effects in the exenatide group.

CONCLUSIONS

Although we failed to reach our planned sample size, the addition of exenatide treatment 10 μg BID SC in T2D patients with uncontrolled HbA1c despite an intensified insulin regimen, resulted in a significant reduction of HbA1c and body weight with a good overall safety profile and acceptance.

Glucose variability and diabetes complications: Risk factor or biomarker? Can we disentangle the "Gordian Knot"?

« Variability in glucose homoeostasis » is a better description than « glycaemic variability » as it encompasses two categories of dysglycaemic disorders: i) the short-term daily glucose fluctuations and ii) long-term weekly, monthly or quarterly changes in either HbA1c, fasting or postprandial plasma glucose. Presently, the relationship between the "variability in glucose homoeostasis" and diabetes complications has never been fully clarified because studies are either observational or limited to retrospective analysis of trials not primarily designed to address this issue. Despite the absence of definitive evidence from randomized controlled trials (RCTs), it is most likely that acute and long-term glucose homoeostasis "cycling", akin to weight and blood pressure "cycling" in obese and hypertensive individuals, are additional risk factors for diabetes complications in the presence of sustained ambient hyperglycaemia. As hypoglycaemic events are strongly associated with short- and long-term glucose variability, two relevant messages can be formulated. Firstly, due consideration should be given to avoid within-day glucose fluctuations in excess of 36% (coefficient of variation) at least for minimizing the inconvenience and dangers associated with hypoglycaemia. Secondly, it seems appropriate to consider that variability in glucose homoeostasis is not only associated with cardiovascular events but is also a causative risk factor via hypoglycaemic episodes as intermediary step. Untangling the" Gordian Knot", to provide confirmation about the impact of variability in glucose homoeostasis and diabetes complications remains a daunting prospect.

Effect of once-weekly dulaglutide versus insulin glargine in people with type 2 diabetes and different baseline glycaemic patterns: A post hoc analysis of the AWARD-2 clinical trial

The long-acting glucagon-like peptide-1 receptor agonist dulaglutide acts by stimulating insulin secretion and reducing glucagon levels in a glucose-dependent manner both in the fasting and postprandial states, resulting in reductions of both fasting glucose (FG) and postprandial glucose (PPG). In contrast, the main mechanism of action of basal insulin is to reduce elevated FG by inhibiting hepatic glucose production. The aim of the present post hoc analysis of the phase 3 AWARD-2 trial was to investigate whether specific baseline glycaemic patterns respond differentially to dulaglutide compared to insulin glargine (glargine). We categorized participants into four subgroups based on prespecified glucose thresholds and their baseline FG and daily 2-hour mean PPG: low FG/low PPG; low FG/high PPG; high FG/low PPG; and high FG/high PPG. Changes in glycaemic measures in response to treatment with dulaglutide or glargine were evaluated in each subgroup. At 52 weeks, significant reductions from baseline in glycated haemoglobin (HbA1c) were observed in all subgroups with dulaglutide 1.5 mg and with glargine (all P < .05), except in patients with low FG/low PPG who received glargine. Greater HbA1c reductions were observed with dulaglutide 1.5 mg compared to glargine in all subgroups (all P ≤ .05), except in the low FG/high PPG subgroup.

Relative contribution of basal and postprandial hyperglycaemia stratified by HbA1c categories before and after treatment intensification with dulaglutide

AIM

To assess the effect of dulaglutide on the relative contribution of basal hyperglycaemia (BHG) and postprandial hyperglycaemia (PPHG) to overall hyperglycaemia across HbA1c categories in patients with type 2 diabetes.

METHODS

Data from five phase 3 studies (N = 673) were pooled to assess the change in relative contributions of BHG and PPHG to overall hyperglycaemia across different HbA1c categories after 6 months of treatment intensification with dulaglutide 1.5 mg as monotherapy or with 1 or 2 oral medication(s) in patients with type 2 diabetes. BHG and PPHG were calculated using the area under the curve (AUC) of 7-point self-monitored plasma glucose concentration profiles. As a secondary objective, relative contribution of BHG and PPHG for dulaglutide versus liraglutide, exenatide BID and insulin glargine was assessed by individual studies at 6 months.

RESULTS

In pooled data, after 6 months of treatment intensification with dulaglutide 1.5 mg, there was a significant reduction from baseline in overall hyperglycaemia (AUC_overall ) [(mean ± SE) -466.31 ± 18.32 mg*h/dL (P < 0.001)], BHG (AUC_basal ) [(mean ± SE) -371.46 ± 16.36 mg*h/dL (P < 0.001)] and PPHG (AUC_postprandial ) [(mean ± SE) -94.84 ± 7.97 mg*h/dL (P < 0.001)]. At baseline, relative contributions of BHG increased and PPHG decreased with increasing HbA1c levels. This pattern was maintained at 6 months, even as overall glycaemia improved with decreasing HbA1c values.

CONCLUSIONS

In patients with type 2 diabetes, dulaglutide reduces HbA1c by lowering both basal and postprandial hyperglycaemia across various HbA1c levels.

Lixisenatide Reduces Chylomicron Triacylglycerol by Increased Clearance

CONTEXT

Glucagon-like peptide-1 (GLP-1) agonists control postprandial glucose and lipid excursion in type 2 diabetes; however, the mechanisms are unclear.

OBJECTIVE

To determine the mechanisms of postprandial lipid and glucose control with lixisenatide (GLP-1 analog) in type 2 diabetes.

DESIGN

Randomized, double-blind, cross-over study.

SETTING

Centre for Diabetes, Endocrinology, and Research, Royal Surrey County Hospital, Guildford, United Kingdom.

PATIENTS

Eight obese men with type 2 diabetes [age, 57.3 ± 1.9 years; body mass index, 30.3 ± 1.0 kg/m2; glycosylated hemoglobin, 66.5 ± 2.6 mmol/mol (8.2% ± 0.3%)].

INTERVENTIONS

Two metabolic studies, 4 weeks after lixisenatide or placebo, with cross-over and repetition of studies.

MAIN OUTCOME MEASURES

Study one: very-low-density lipoprotein (VLDL) and chylomicron (CM) triacylglycerol (TAG) kinetics were measured with an IV bolus of [2H5]glycerol in a 12-hour study, with hourly feeding. Oral [13C]triolein, in a single meal, labeled enterally derived TAG. Study two: glucose kinetics were measured with [U-13C]glucose in a mixed-meal (plus acetaminophen to measure gastric emptying) and variable IV [6,6-2H2]glucose infusion.

RESULTS

Study one: CM-TAG (but not VLDL-TAG) pool-size was lower with lixisenatide (P = 0.046). Lixisenatide reduced CM [13C]oleate area under the curve (AUC)60-480min concentration (P = 0.048) and increased CM-TAG clearance, with no effect on CM-TAG production rate. Study two: postprandial glucose and insulin AUC0-240min were reduced with lixisenatide (P = 0.0051; P < 0.05). Total glucose production (P = 0.015), rate of glucose appearance from the meal (P = 0.0098), and acetaminophen AUC0-360min (P = 0.006) were lower with lixisenatide than with placebo.

CONCLUSIONS

Lixisenatide reduced [13C]oleate concentrations, derived from a single meal in CM-TAG and glucose rate of appearance from the meal through delayed gastric emptying. However, day-long CM production, measured with repeated meal feeding, was not reduced by lixisenatide and decreased CM-TAG concentration resulted from increased CM-TAG clearance.

Glycemic Variability: How to Measure and Its Clinical Implication for Type 2 Diabetes

Glycated hemoglobin A1c (A1C) levels have traditionally been the gold standard for assessing glycemic control and treatment efficacy in patients with type 2 diabetes. However, A1C does not take into account fluctuations in blood glucose levels known as glycemic variability (GV). In recent years, GV has become increasingly clinically relevant, because of a better understanding of the need to reach target A1C while avoiding hypoglycemia. GV relates to both hyperglycemia and hypoglycemia, and has been associated with poorer quality of life. Diabetes treatments targeting multiple pathophysiological mechanisms are most beneficial in controlling A1C and reducing GV. In clinical trials, a number of metrics are used to measure GV, many of which are not well understood in the clinical practice. Until a gold standard metric for GV is established, the variety of measurements available may confound the choice of an optimal treatment for an individual patient.

Propensity-score-matched comparative analyses of simultaneously administered fixed-ratio insulin glargine 100 U and lixisenatide (iGlarLixi) vs sequential administration of insulin glargine and lixisenatide in uncontrolled type 2 diabetes

AIM

To conduct two exploratory analyses to compare indirectly the efficacy and safety of simultaneous administration of insulin glargine 100 U (iGlar) and the glucagon-like peptide-1 receptor agonist (GLP-1RA) lixisenatide (Lixi) as a single-pen, titratable, fixed-ratio combination (iGlarLixi [LixiLan trials]) vs sequential administration of iGlar + Lixi (GetGoal Duo trials) in people with type 2 diabetes (T2D).

MATERIALS AND METHODS

Propensity-score matching based on baseline covariates was used to compare simultaneous iGlarLixi vs sequential combination of iGlar + Lixi with the addition of Lixi in patients who did not reach the glycated haemoglobin (HbA1c) goal of <53 mmol/mol (<7%) after short-term use of iGlar alone (LixiLan-O vs GetGoal Duo-1 comparison) and vs sequential addition of Lixi in uncontrolled patients after long-term use of iGlar alone (LixiLan-L vs GetGoal Duo-2 comparison).

RESULTS

In both analyses, compared with sequential iGlar + Lixi, iGlarLixi led to significantly greater HbA1c reductions with associated weight loss and significantly more patients reaching target HbA1c <53 mmol/mol despite lower insulin doses. Symptomatic hypoglycaemia rates were similar, despite greater HbA1c reductions with iGlarLixi. Lower rates of gastrointestinal adverse events were observed with iGlarLixi, probably as a result of the more gradual titration of Lixi with iGlarLixi.

CONCLUSIONS

Indirect propensity-score-matched exploratory comparisons suggest that early treatment with a simultaneous, titratable, fixed-ratio combination of basal insulin and a GLP-1RA (iGlarLixi) may be more effective and possess better gastrointestinal tolerability than a sequential approach of adding a GLP-1RA in patients with uncontrolled T2D initiating or intensifying basal insulin therapy.

After the LEADER trial and SUSTAIN-6, how do we explain the cardiovascular benefits of some GLP-1 receptor agonists?

Recent cardiovascular outcome trials - the LEADER with liragutide and SUSTAIN-6 with semaglutide - have shown significant reductions of major cardiovascular (CV) events with these glucagon-like peptide (GLP)-1 receptor agonists. Progressive separation of the treatment and placebo curves, starting clearly between 12 and 18 months of the trial period, and significant reductions in the risk of myocardial infarction and stroke, indicate that the beneficial CV effects observed with GLP-1 receptor agonists could be due to an antiatherogenic effect. So far, the reasons for such an effect of GLP-1 receptor agonists have not been entirely clear, although several hypotheses may be proposed. As the reductions in glycated haemoglobin and systolic blood pressure (SBP) in these trials were modest, and both trials lasted only a short period of time, reductions in hyperglycaemia and SBP are unlikely to be involved in the beneficial CV effects of GLP-1 receptor agonists. On the other hand, their effect on lipids and, in particular, the dramatic decrease in postprandial hypertriglyceridaemia may explain their beneficial CV actions. Reduction of body weight, including a significant decrease in visceral fat in patients using GLP-1 receptor agonists, may also have beneficial CV effects by reducing chronic proatherogenic inflammation. In addition, there are in-vitro data showing a direct anti-inflammatory effect with these agents that could also be involved in their beneficial CV effects. Moreover, studies in humans have shown significant beneficial effects on ischaemic myocardium after a very short treatment period, suggesting a direct effect of GLP-1 receptor agonists on myocardium, although the precise mechanism remains unclear. Finally, as a reduction in insulin resistance has been associated with a decrease in CV risk, it cannot be ruled out that the lowering of insulin resistance induced by GLP-1 receptor agonists might also be involved in their beneficial CV actions.

Addition of once daily prandial lixisenatide to basal insulin therapy in patients with type-2 diabetes results in a reduction of HbA1c as an effect of postprandial glucose lowering

AIMS

Basal insulin has been shown to effectively reduce fasting blood glucose (FBG), but postprandial plasma glucose (PPG) excursions may remain higher than normal. Glucagon-like peptide (GLP)-1 receptor agonists such as the short-acting lixisenatide are able to control such excursions by slowing gastric emptying. However, data regarding its use in a real world clinical setting are scarce.

METHODS

24 week, prospective, multicentre, non-interventional study in 1437 patients with type-2 diabetes receiving 20μg lixisenatide once daily in combination with basal insulin. The per-protocol set (PPS) comprised 540 patients.

RESULTS

HbA_1c levels were found to decrease significantly over 24 weeks of treatment in the PPS (0.94±0.99% [7.9±8.5]; p≤0.001). An HbA_1c of <7% (53mmol/mol) was achieved in 26.9% of patients, with 9.8% reaching <6.5% (48mmol/mol) and 30.0% reaching their individual treatment goal. There was a slight decrease in FBG (2.84±30.4mg/dl; p≤0.001), and a significant reduction in PPG, with levels decreasing by between 35mg/dl (1.9mmol/l) and 38mg/dl (2.1mmol/l), respectively on average after all main meals in basal optimised patients (PPS; ≤140mg/dl). Body weight decreased from 101 to 98kg with a mean difference of 3.10±4.10kg (p≤0.001). There were few reports of hypoglycaemia and no reports of serious hypoglycaemia and need for external help. AEs were infrequent, and were in line with previous studies.

CONCLUSIONS

Lixisenatide in combination with basal insulin was shown to be an effective treatment strategy for patients with type 2 diabetes, controlling HbA_1c levels by reduction of PPG excursions during the whole day.

Future challenges and therapeutic opportunities in type 2 diabetes: Changing the paradigm of current therapy

Most algorithms for type 2 diabetes mellitus (T2DM) do not recommend treatment escalation until glycated haemoglobin (HbA1c) fails to reach the recommended target of 7% (53 mmol/mol) within approximately 3 months on any treatment regimen ("treat to failure"). Clinical inertia and/or poor adherence to therapy contribute to patients not reaching glycaemic targets when managed according to this paradigm. Clinical inertia exists across the entire spectrum of anti-diabetes therapies, although it is most pronounced when initiating and optimizing insulin therapy. Possible reasons include needle aversion, fear of hypoglycaemia, excessive weight gain and/or the need for increased self-monitoring of blood glucose. Studies have suggested, however, that early intensive insulin therapy in newly diagnosed, symptomatic patients with T2DM with HbA1c >9% (75 mmol/mol) can preserve beta-cell function, thereby modulating the disease process. Furthermore, postprandial plasma glucose is a key component of residual dysglycaemia, evident especially when HbA1c remains above target despite fasting normoglycaemia. Therefore, to achieve near normoglycaemia, additional treatment with prandial insulin or a glucagon-like peptide-1 receptor agonist (GLP-1 RA) is often required. Long- or short-acting GLP-1 RAs offer effective alternatives to basal or prandial insulin in patients inadequately controlled with other therapies or basal insulin alone, respectively. This review highlights the limitations of current algorithms, and proposes an alternative based on the early introduction of insulin therapy and the rationale for the sequential or fixed combination of GLP-1 RAs with insulin ("treat-to-success" paradigm).

Glucagon-Like Peptide-1 (GLP-1) Treatment Ameliorates Cognitive Impairment by Attenuating Arc Expression in Type 2 Diabetic Rats

Background

Glucagon-like peptide-1 (GLP-1) has been reported to exert some beneficial effects on the central nervous system (CNS). However, the effect of GLP-1 on cognitive impairment associated with type 2 diabetes is not well known. This study investigated the effect of GLP-1 on ameliorating memory deficits in type 2 diabetic rats.

Material/Methods

Type 2 diabetic rats were induced by a high-sugar, high-fat diet, followed by streptozotocin (STZ) injection and then tested in the Morris Water Maze (MWM) 1 week after the induction of diabetes. The mRNA expression of Arc, APP, BACE1, and PS1 were determined by real-time quantitative PCR, and the Arc protein was analyzed by immunoblotting and immunohistochemistry.

Results

Type 2 diabetic rats exhibited a significant decline in learning and memory in the MWM tests, but GLP-1 treatment was able to protect this decline and significantly improved learning ability and memory. The mRNA expression assays showed that GLP-1 treatment markedly reduced Arc, APP, BACE1, and PS1 expressions, which were elevated in the diabetic rats. Immunoblotting and immunohistochemistry results also confirmed that Arc protein increased in the hippocampus of diabetic rats, but was reduced after GLP-1 treatment.

Conclusions

Our findings suggest that GLP-1 treatment improves learning and memory deficits in type 2 diabetic rats, and this effect is likely through the reduction of Arc expression in the hippocampus.

Targeting One-Hour Postmeal Glucose: Is It Time for a Paradigm Switch in Diabetes Management?

In the management of diabetes, postprandial glycemia (PPG) is usually targeted 2 h after the start of meal. Recent evidences, however, suggest that the value of glycemia at 1 h during an oral glucose tolerance test (OGTT) is a stronger predictor for developing diabetes than the value at 2 h and that it is an independent risk factor for cardiovascular disease. Studies in cells, animals, and humans suggest that 1-h high glucose is a sufficient stimulus for increasing several cardiovascular risk factors, such as inflammation, thrombosis, and endothelial dysfunction, with oxidative stress generation as the possible pathogenetic factor. One-hour glucose might be more dangerous than that at 2 h simply because glycemia is higher at 1 h, during an OGTT and postmeal. The new drugs, able to target better 1 h glycemia and the new noninvasive technologies for glucose monitoring, nowadays may help to change the therapeutic paradigm of targeting PPG at 2 h.

Lixisenatide reduces glycaemic variability in insulin-treated patients with type 2 diabetes

Chronic hyperglycaemia and glucose variability are associated with the development of chronic diabetes-related complications. We conducted a pooled analysis of patient-level data from three 24-week, randomized, phase III clinical trials to evaluate the impact of lixisenatide (LIXI) on glycaemic variability (GV) vs placebo as add-on to basal insulin. The main outcome GV measures were standard deviation (s.d.), mean amplitude of glycaemic excursions (MAGE), mean absolute glucose (MAG) level, area under the curve for fasting glucose (AUC-F), and high (HBGI) and low blood glucose index (LBGI). The change in GV metrics over 24 weeks and relationships among baseline GV, patient characteristics and outcomes were assessed. Data were pooled from 1198 patients (665 LIXI, 533 placebo). Values for s.d., MAG level, MAGE, HBGI, and AUC-F significantly decreased with LIXI vs placebo, while LBGI values were unchanged. Higher baseline GV measures correlated with older age, longer type 2 diabetes duration, lower body mass index, higher baseline glycated/haemogobin, greater reduction in postprandial glucose (PPG) level, and higher rates of symptomatic hypoglycaemia. These data show that LIXI added to basal insulin significantly reduced GV and PPG excursions vs placebo, without increasing the risk of hypoglycaemia (LBGI).

Basal insulin treatment intensification in patients with type 2 diabetes mellitus: A comprehensive systematic review of current options

AIM

As type 2 diabetes mellitus progresses, most patients require treatment with basal insulin in combination with another agent to achieve recommended glycaemic targets. The purpose of this systematic review was to examine the evidence supporting the use of the available add-on treatments [rapid-acting insulin (RAI), glucagon-like peptide-1 receptor agonists (GLP-1 RAs), dipeptidyl peptidase (DPP)-4 inhibitors and sodium-glucose cotransporter-2 (SGLT-2) inhibitors] to basal insulin.

METHODS

MEDLINE, EMBASE and EBSCOhost were searched for English-language articles, and all those captured were original articles (case studies and narrative reviews were omitted). Data on study design, population demographics, interventions and outcomes were tabulated. The extracted outcome data included changes in glycated haemoglobin (HbA_1c), fasting plasma glucose (FPG) and postprandial plasma glucose (PPG), as well as body weight and safety data.

RESULTS

A total of 88 publications were deemed relevant. All treatments reduced HbA_1c and FPG. The most pronounced reductions in PPG, an unmet need in patients not controlled by basal insulin, were seen following administration of RAIs and short-acting GLP-1 RAs, although data for this outcome are generally lacking. Body weight benefits were observed with GLP-1 RAs and SGLT-2 inhibitors. However, as only articles in English were included, the result was a possible publication bias, while the diversity of study designs and drug combinations limited comparisons between studies.

CONCLUSION

The evidence supports effectiveness of the available add-on treatments to basal insulin. However, other factors, such as potential body-weight increases, convenience/compliance and adverse events, particularly hypoglycaemia, should be considered on a patient-by-patient basis to optimalize treatment outcomes.

Is there a justification for classifying GLP-1 receptor agonists as basal and prandial?

Several GLP-1 receptor agonists are currently available for treatment of type 2 diabetic patients. Based on their pharmacokinetic/pharmacodynamic profile, these drugs are classified as short-acting GLP-1 receptor agonists (exenatide and lixisenatide) or long-acting GLP-1 receptor agonists (exenatide-LAR, liraglutide, albiglutide, and dulaglutide). In clinical practice, they are also classified as basal or prandial GLP-1 receptor agonists to differentiate between patients who would benefit more from one or another based on characteristics such as previous treatment and the predominance of fasting or postprandial hyperglycemia. In the present article we examine available data on the pharmacokinetic characteristics of the various GLP-1 agonists and compare their effects with respect to the main parameters used to evaluate glycemic control. The article also analyzes whether the differences between the different GLP-1 agonists justify their classification as basal or prandial.

GLP-1 RAs as compared to prandial insulin after failure of basal insulin in type 2 diabetes: lessons from the 4B and Get-Goal DUO 2 trials

The add-on of a prandial (short-acting) GLP-1 RA to basal insulin in subjects with T2DM who fail to control A1C on basal insulin, stems from the physiological principles of post-prandial glucose homeostasis, and it is based on evidence from clinical trials. The 4B and GetGoal DUO 2 studies are the first to establish in head-to-head comparison, the efficacy and safety of short-acting GLP-1 RAs vs prandial insulin, when added-on to basal insulin glargine. In the 4B study (exenatide 2/d vs lispro 3/d) exenatide demonstrated similar efficacy vs lispro in reducing A1C to ~7.2%. However, exenatide reduced also body weight and hypoglycemia incidence as compared to lispro. In GetGoal DUO 2, the head-to-head comparison was between lixisenatide 1/d vs glulisine either 1/d (at the main meal, basal-plus) or 3/d (basal-bolus). Like in 4B, in GetGoal DUO 2 the A1C decreased to similar values with lixisenatide or glulisine 1/d (~7.2%), or glulisine 3/d (~7.0%). Again, as in the 4B, body weight and hypoglycemia incidence were lower with lixisenatide. In both studies a similar percentage of subjects reached the A1C <7.0% on GLP-1 RA or prandial insulin. A higher percentage of subjects reported adverse events on GLP-1 RAs, primarily gastrointestinal related. The studies 4B and GetGoal DUO 2 suggest that after failure of basal insulin in T2DM, the add-on of prandial GLP-1 RA is as effective as prandial insulin in lowering A1C, with added benefits of reducing body weight and risk for hypoglycemia. In addition, the GLP-1 RA + basal insulin is a simpler therapeutic option as compared to basal-plus and basal-bolus regimens.

Postprandial and basal hyperglycaemia in type 2 diabetes: Contributions to overall glucose exposure and diabetic complications

Both postprandial and fasting (basal) hyperglycaemia contribute to overall hyperglycaemia (ambient hyperglycaemia) in type 2 diabetes (T2D). Postprandial glucose is the main contributor in fairly well controlled individuals, whereas basal hyperglycaemia becomes the preponderant contributor in poorly controlled patients. A more generally acceptable description of the contribution of postprandial glucose is to simply say that the absolute impact of postprandial glucose to HbA1c remains constant at approximately 1% across the entire HbA1c spectrum of non-insulin-treated patients with T2D. While epidemiological and pathophysiological studies seem to indicate that excessive postprandial glucose excursions play a role in or are predictors of cardiovascular diseases, there is still currently a lack of clinical evidence that correcting post-meal hyperglycaemia can improve clinical outcomes. However, even in the absence of consensus, there are many reasons for thinking that excessive postprandial glucose might be an independent risk factor for diabetic complications as it contributes to both overall glucose exposure and glycaemic variability, especially in those who have HbA1c levels < 7.5-8%. Given that excessive glucose fluctuations from peaks to nadirs activate oxidative stress, it seems reasonable to consider that a key player in the pathogenesis of diabetic complications, according to the latest IDF guidelines, is post-meal glucose, thereby warranting its assessment and treatment when found at abnormally elevated levels. Nevertheless, healthcare professionals should bear in mind that targeting both post-meal and basal plasma glucose, giving equal consideration to both of them, is probably the best strategy for achieving optimal glycaemic control and thus preventing or reducing the risk of diabetic complications.

Once-daily liraglutide (1.2 mg) compared with twice-daily exenatide (10 μg) in the treatment of type 2 diabetes patients: An indirect treatment comparison meta-analysis

BACKGROUND

Glucagon-like peptide-1 receptor agonists provide effective hyperglycemia management in patients with type 2 diabetes. In a randomized head-to-head trial, liraglutide 1.8 mg q.d. led to greater reductions in HbA1c than exenatide 10 μg b.i.d. There are no direct comparisons of liraglutide 1.2 mg q.d. and exenatide b.i.d.; therefore, in the present study, an indirect comparison and meta-analysis were undertaken.

METHODS

A systematic literature search was performed for randomized controlled trials of liraglutide 1.2 mg q.d. or exenatide b.i.d. with HbA1c as an outcome and ≥25 subjects. Key data were extracted and analyzed. A random-effects model was used to incorporate heterogeneity between studies.

RESULTS

Three liraglutide 1.2 mg q.d. (n = 1060) and 10 exenatide b.i.d. (n = 2609) placebo-controlled studies were identified, allowing indirect comparison with placebo as the common arm. Baseline characteristics were mean age ~55 years, disease duration ~7 years, HbA1c ~8%, and body mass index ~32 kg/m² . Compared with exenatide b.i.d., liraglutide 1.2 mg was associated with significantly greater reductions from baseline in HbA1c (-0.29%; 95% confidence interval [CI] -0.53, -0.05) and fasting plasma glucose (-0.92 mmol/L; 95% CI -1.43, -0.41), with shorter duration of nausea (3 vs 14 days; P = 0.002) and fewer withdrawals (odds ratio 0.34; 95% CI 0.22, 0.52). The incidence of adverse events (including nausea) and withdrawals because of adverse events were similar between treatments.

CONCLUSIONS

Liraglutide 1.2 mg provided a significantly greater reduction in HbA1c than exenatide 10 μg b.i.d. The significantly shorter duration of nausea with liraglutide than exenatide may be appreciated by patients.

Pharmacology and therapeutic implications of current drugs for type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a global epidemic that poses a major challenge to health-care systems. Improving metabolic control to approach normal glycaemia (where practical) greatly benefits long-term prognoses and justifies early, effective, sustained and safety-conscious intervention. Improvements in the understanding of the complex pathogenesis of T2DM have underpinned the development of glucose-lowering therapies with complementary mechanisms of action, which have expanded treatment options and facilitated individualized management strategies. Over the past decade, several new classes of glucose-lowering agents have been licensed, including glucagon-like peptide 1 receptor (GLP-1R) agonists, dipeptidyl peptidase 4 (DPP-4) inhibitors and sodium/glucose cotransporter 2 (SGLT2) inhibitors. These agents can be used individually or in combination with well-established treatments such as biguanides, sulfonylureas and thiazolidinediones. Although novel agents have potential advantages including low risk of hypoglycaemia and help with weight control, long-term safety has yet to be established. In this Review, we assess the pharmacokinetics, pharmacodynamics and safety profiles, including cardiovascular safety, of currently available therapies for management of hyperglycaemia in patients with T2DM within the context of disease pathogenesis and natural history. In addition, we briefly describe treatment algorithms for patients with T2DM and lessons from present therapies to inform the development of future therapies.

Gut feedback mechanisms and food intake: a physiological approach to slow carbohydrate bioavailability

Glycemic carbohydrates in foods are an important macronutrient providing the biological fuel of glucose for a variety of physiological processes. A classification of glycemic carbohydrates into rapidly digestible carbohydrate (RDC) and slowly digestible carbohydrate (SDC) has been used to specify their nutritional quality related to glucose homeostasis that is essential to normal functioning of the brain and critical to life. Although there have been many studies and reviews on slowly digestible starch (SDS) and SDC, the mechanisms of their slow digestion and absorption were mostly investigated from the material side without considering the physiological processes of their in vivo digestion, absorption, and most importantly interactions with other food components and the gastrointestinal tract. In this article, the physiological processes modulating the bioavailability of carbohydrates, specifically the rate and extent of their digestion and absorption as well as the related locations, in a whole food context, will be discussed by focusing on the activities of the gastrointestinal tract including glycolytic enzymes and glucose release, sugar sensing, gut hormones, and neurohormonal negative feedback mechanisms. It is hoped that a deep understanding of these physiological processes will facilitate the development of innovative dietary approaches to achieve desired carbohydrate or glucose bioavailability for improved health.

Near normal HbA1c with stable glucose homeostasis: the ultimate target/aim of diabetes therapy

Achieving near normal glucose homeostasis implies that all components of dysglycemia that are present in diabetes states be eliminated. Reducing ambient/overall hyperglycemia is a pre-requisite to eliminate the risk of development and progression of diabetes complications. More controversially however, are the relative and related contributions of postprandial glucose excursions, glucose variability, hypoglycemia and the dawn phenomenon across the spectrum of dysglycemia. For instance, it is likely that the dawn phenomenon contributes to ambient hyperglycemia and that postprandial glucose excursions are at the cross road of ambient hyperglycemia and glucose variability with glucose fluctuations as causative risk factors for hypoglycemia. Proof-of-concept trials such as the ongoing FLAT-SUGAR study are necessary for gaining further insight into the possible harmful effects of some of these features such as excessive glycemic variability and glucose excursions, still considered to be of minor relevance by several diabetologists. Whether their role will be more thoroughly proven through further intervention trials with "hard" endpoints, remains to be seen. In the meantime more consideration should be given to medications aimed at concomitantly reducing ambient/overall hyperglycemia and those additional abnormal glycemic features of dysglycemia.

GLP-1 Receptor Agonists: Practical Considerations for Clinical Practice

PURPOSE

Type 2 diabetes (T2D) imparts an increased risk of adverse health outcomes in patients unable to achieve glycemic control. Patient education and individualization of treatment are important for effective management of T2D. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are a class of injectable glucose-lowering agents that lower A1C with added benefits of weight loss and improved cardiovascular risk markers. This review discusses the role of GLP-1RAs currently approved in the United States (exenatide, liraglutide, albiglutide, dulaglutide) for T2D management and characterizes the efficacy and safety profiles of individual GLP-1RAs.

CONCLUSIONS

GLP-1RAs are recommended as a preferred add-on agent to existing metformin monotherapy, as first-line therapy if metformin is contraindicated or poorly tolerated, and for use in combination with other oral glucose-lowering agents or basal insulin. Shorter-acting GLP-1RAs (exenatide and liraglutide) offer improved coverage of postprandial hyperglycemia, while longer-acting GLP-1RA formulations (exenatide extended-release, dulaglutide, and albiglutide) further improve fasting plasma glucose, which can result in additional A1C lowering. Reductions in body weight and blood pressure appear similar among individual agents, and small increases in heart rate are of unknown clinical relevance. Gastrointestinal adverse events abate over time with continued treatment and are less frequent with longer-acting GLP-1RAs. Hypoglycemia incidence is low but increased when GLP-1RAs are used with insulin secretagogues or insulin. GLP-1RAs target multiple pathophysiologic mechanisms in patients with T2D and improve glycemic control, although there are some differences within this drug class that may be relevant in clinical practice. Therefore, selection of the most appropriate treatment for individual patients is important.

Pharmacokinetics and clinical use of incretin-based therapies in patients with chronic kidney disease and type 2 diabetes

The prevalence of chronic kidney disease (CKD) of stages 3-5 (glomerular filtration rate [GFR] <60 mL/min) is about 25-30 % in patients with type 2 diabetes mellitus (T2DM). While most oral antidiabetic agents have limitations in patients with CKD, incretin-based therapies are increasingly used for the management of T2DM. This review analyses (1) the influence of CKD on the pharmacokinetics of dipeptidyl peptidase-4 (DPP-4) inhibitors and glucagon-like peptide-1 (GLP-1) receptor agonists; and (2) the efficacy/safety profile of these agents in clinical practice when prescribed in patients with both T2DM and CKD. Most DPP-4 inhibitors (sitagliptin, vildagliptin, saxagliptin, alogliptin) are predominantly excreted by the kidneys. Thereby, pharmacokinetic studies showed that total exposure to the drug is increased in proportion to the decline of GFR, leading to recommendations for appropriate dose reductions according to the severity of CKD. In these conditions, clinical studies reported a good efficacy and safety profile in patients with CKD. In contrast, linagliptin is eliminated by a predominantly hepatobiliary route. As a pharmacokinetic study showed only minimal influence of decreased GFR on total exposure, no dose adjustment of linagliptin is required in the case of CKD. The experience with GLP-1 receptor agonists in patients with CKD is more limited. Exenatide is eliminated by renal mechanisms and should not be given in patients with severe CKD. Liraglutide is not eliminated by the kidney, but it should be used with caution because of the limited experience in patients with CKD. Only limited pharmacokinetic data are also available for lixisenatide, exenatide long-acting release (LAR) and other once-weekly GLP-1 receptor agonists in current development. Several case reports of acute renal failure have been described with GLP-1 receptor agonists, probably triggered by dehydration resulting from gastrointestinal adverse events. However, increasing GLP-1 may also exert favourable renal effects that could contribute to reducing the risk of diabetic nephropathy. In conclusion, the already large reassuring experience with DPP-4 inhibitors in patients with CKD offers new opportunities to the clinician, whereas more caution is required with GLP-1 receptor agonists because of the limited experience in this population.

Contrasting Effects of Lixisenatide and Liraglutide on Postprandial Glycemic Control, Gastric Emptying, and Safety Parameters in Patients With Type 2 Diabetes on Optimized Insulin Glargine With or Without Metformin: A Randomized, Open-Label Trial

OBJECTIVE

This mechanistic trial compared the pharmacodynamics and safety of lixisenatide and liraglutide in combination with optimized insulin glargine with/without metformin in type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

This was a multicenter, randomized, open-label, three-arm trial comparing lixisenatide 20 µg and liraglutide 1.2 and 1.8 mg once daily for 8 weeks in combination with insulin glargine after optimized titration. The primary end point was change from baseline to week 8 in incremental area under the postprandial plasma glucose curve for 4 h after a standardized solid breakfast (AUC PPG0030-0430 h). Changes from baseline in gastric emptying, 24-h plasma glucose profile, HbA1c, fasting plasma glucose (FPG), 24-h ambulatory heart rate and blood pressure, amylase and lipase levels, and adverse events (AEs) were also assessed.

RESULTS

In total, 142 patients were randomized and treated. Lixisenatide 20 µg achieved greater reductions of AUC PPG0030-0430 h compared with liraglutide (marginal mean [95% one-sided CI] treatment difference, -6.0 [-7.8] h ⋅ mmol/L [-108.3 (-140.0) h ⋅ mg/dL] vs. liraglutide 1.2 mg and -4.6 [-6.3] h ⋅ mmol/L [-83.0 (-114.2) h ⋅ mg/dL] vs. liraglutide 1.8 mg; P < 0.001 for both), and gastric emptying was delayed to a greater extent than with liraglutide 1.2 and 1.8 mg (P < 0.001 for treatment comparisons). FPG was unchanged in all treatment arms. At week 8, mean ± SD HbA1c was 6.2 ± 0.4% (44 ± 5 mmol/mol), 6.1 ± 0.3% (44 ± 4 mmol/mol), and 6.1 ± 0.3% (44 ± 4 mmol/mol) for lixisenatide 20 µg and liraglutide 1.2 and 1.8 mg, respectively. At week 8, both liraglutide doses increased marginal mean ± SE 24-h heart rate from baseline by 9 ± 1 bpm vs. 3 ± 1 bpm with lixisenatide (P < 0.001). Occurrence of symptomatic hypoglycemia was higher with lixisenatide; gastrointestinal AEs were more common with liraglutide. Lipase levels were significantly increased from baseline with liraglutide 1.2 and 1.8 mg (marginal mean ± SE increase 21 ± 7 IU/L for both; P < 0.05).

CONCLUSIONS

Lixisenatide and liraglutide improved glycemic control in optimized insulin glargine-treated T2D albeit with contrasting mechanisms of action and differing safety profiles.

The Role of Glucagon-Like Peptide-1 Receptor Agonists in Type 2 Diabetes: Understanding How Data Can Inform Clinical Practice in Korea

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) reduce glycosylated hemoglobin (HbA1c, 0.5% to 1.0%), and are associated with moderate weight loss and a relatively low risk of hypoglycemia. There are differences between Asian and non-Asian populations. We reviewed available data on GLP-1RAs, focusing on Korean patients, to better understand their risk/benefit profile and help inform local clinical practice. Control of postprandial hyperglycemia is important in Asians in whom the prevalence of post-challenge hyperglycemia is higher (vs. non-Asians). The weight lowering effects of GLP-1RAs are becoming more salient as the prevalence of overweight and obesity among Korean patients increases. The higher rate of gastrointestinal adverse events amongst Asian patients in clinical trials may be caused by higher drug exposure due to the lower body mass index of the participants (vs. non-Asian studies). Data on the durability of weight loss, clinically important health outcomes, safety and optimal dosing in Korean patients are lacking. Use of GLP-1RAs is appropriate in several patient groups, including patients whose HbA1c is uncontrolled, especially if this is due to postprandial glucose excursions and patients who are overweight or obese due to dietary problems (e.g., appetite control). The potential for gastrointestinal adverse events should be explained to patients at treatment initiation to facilitate the promotion of better compliance.

Pharmacokinetics in patients with chronic liver disease and hepatic safety of incretin-based therapies for the management of type 2 diabetes mellitus

Patients with type 2 diabetes mellitus have an increased risk of chronic liver disease (CLD) such as non-alcoholic fatty liver disease and steatohepatitis, and about one-third of cirrhotic patients have diabetes. However, the use of several antidiabetic agents, such as metformin and sulphonylureas, may be a concern in case of hepatic impairment (HI). New glucose-lowering agents targeting the incretin system are increasingly used for the management of type 2 diabetes. Incretin-based therapies comprise oral inhibitors of dipeptidyl peptidase-4 (DPP-4) (gliptins) or injectable glucagon-like peptide-1 (GLP-1) receptor agonists. This narrative review summarises the available data regarding the use of both incretin-based therapies in patients with HI. In contrast to old glucose-lowering agents, they were evaluated in specifically designed acute pharmacokinetic studies in patients with various degrees of HI and their hepatic safety was carefully analysed in large clinical trials. Only mild changes in pharmacokinetic characteristics of DPP-4 inhibitors were observed in patients with different degrees of HI, presumably without major clinical relevance. GLP-1 receptor agonists have a renal excretion rather than liver metabolism. Specific pharmacokinetic data in patients with HI are only available for liraglutide. No significant changes in liver enzymes were reported with DPP-4 inhibitors or GLP-1 receptor agonists, alone or in combination with various other glucose-lowering agents, in clinical trials up to 2 years in length. On the contrary, preliminary data suggested that incretin-based therapies may be beneficial in patients with CLD, more particularly in the presence of non-alcoholic fatty liver disease. Nevertheless, caution should be recommended, especially in patients with advanced cirrhosis, because of a lack of clinical experience with incretin-based therapies in these vulnerable patients.

"Mild dysglycemia" in type 2 diabetes: to be neglected or not?

"Mild dysglycemia" in type 2 diabetes can be defined by the range of HbA1c levels≥6.5% (48 mmol/mol) and<7% (53 mmol/mol), which corresponds to when the risk for vascular complications begins to increase. This "mild dysglycemia" is characterized by both a dawn phenomenon (a spontaneous blood glucose rise in the early morning) and an excess of post-prandial glucose excursions in the absence of abnormal elevation in basal glucose, especially during nocturnal periods. This represents an intermediary stage between pre-diabetes (HbA1c≥5.7%, 39 mmol/mol, and<6.5%, 48 mmol/mol) and those who begin to show a steadily progressive worsening in basal glucose (HbA1c≥7%, 53 mmol/mol). Should this relatively minor intermediate dysglycemic phase deserve more attention, that is the question. The now available incretin-based therapies, and more specifically the DPP-4 inhibitors provide the clinician with the possibility to reduce or eradicate both the dawn phenomenon and post-meal glucose excursions with minimal side effects. The availability of 24-h glycemic profiles in those with "mild dysglycemia" will help to describe their individual glycemic phenotype, based on which the early and appropriate life style changes and/or pharmacological interventions can be introduced.

Anion Gap Toxicity in Alloxan Induced Type 2 Diabetic Rats Treated with Antidiabetic Noncytotoxic Bioactive Compounds of Ethanolic Extract of Moringa oleifera

Moringa oleifera (MO) is used for a number of therapeutic purposes. This raises the question of safety and possible toxicity. The objective of the study was to ascertain the safety and possible metabolic toxicity in comparison with metformin, a known drug associated with acidosis. Animals confirmed with diabetes were grouped into 2 groups. The control group only received oral dose of PBS while the test group was treated with ethanolic extract of MO orally twice daily for 5-6 days. Data showed that the extract significantly lowered glucose level to normal values and did not cause any significant cytotoxicity compared to the control group (P = 0.0698); there was no gain in weight between the MO treated and the control groups (P > 0.8115). However, data showed that treatment with an ethanolic extract of MO caused a decrease in bicarbonate (P < 0.0001), and more than twofold increase in anion gap (P < 0.0001); metformin treatment also decreased bicarbonate (P < 0.0001) and resulted in a threefold increase in anion gap (P < 0.0001). Conclusively, these data show that while MO appears to have antidiabetic and noncytotoxic properties, it is associated with statistically significant anion gap acidosis in alloxan induced type 2 diabetic rats.

Measurement of gastric emptying in diabetes

There has been a substantial evolution of concepts related to disordered gastric emptying in diabetes. While the traditional focus has hitherto related to the pathophysiology and management of upper gastrointestinal symptoms associated with gastroparesis, it is now apparent that the rate of gastric emptying is central to the regulation of postprandial glycemia. This recognition has stimulated the development of dietary and pharmacologic approaches to optimize glycemic control, at least in part, by slowing gastric emptying. With the increased clinical interest in this area, it has proved necessary to expand the traditional indications for gastric emptying studies, and consider the relative strengths and limitations of available techniques. Scintigraphy remains the 'gold standard' for the measurement of gastric emptying, however, there is a lack of standardization of the technique, and the optimal test meal for the evaluation of gastrointestinal symptoms may be discordant from that which is optimal to assess impaired glycemic control. The stable isotope breath test provides an alternative to scintigraphy and can be performed in an office-based setting. The effect of glucagon-like peptide-1 (GLP-1) and its agonists to reduce postprandial glycemia is dependent on the baseline rate of gastric emptying, as well as the magnitude of slowing. Because the effect of exogenous GLP-1 to slow gastric emptying is subject to tachyphylaxis with sustained receptor exposure, 'short acting' or 'prandial' GLP-1 agonists primarily target postprandial glycemia through slowing of gastric emptying, while 'long acting' or 'non-prandial' agents lower fasting glucose primarily through insulinotropic and glucagonostatic mechanisms. Accordingly, the indications for the therapeutic use of these different agents are likely to vary according to baseline gastric emptying rate and glycemic profiles.

Residual dysglycemia when at target HbA(1c) of 7% (53mmol/mol) in persons with type 2 diabetes

AIMS

To understand the composition of the residual dysglycemia when HbA1c is between 6.5% (48mmol/mol) and 7% (53mmol/mol), representing the definition of diabetes and the recommended treatment goal, respectively.

METHODS

One hundred persons with type 2 diabetes and a HbA1c<7% (53mmol/mol), treated with diet alone and/or oral hypoglycemic agents underwent continuous glucose monitoring (CGM) and were further divided into two subgroups 1 (n=50) and 2 (n=50) according to whether the HbA1c was <6.5% (48mmol/mol) or 6.5-6.9% (48-52mmol/mol), respectively. A similar analysis was performed in those on diet alone: subgroups A (n=34, HbA1c<6.5%, 48mmol/mol) and B (n=10, HbA1c 6.5-6.9%, 48-52mmol/mol). The residual dysglycemia determined from the CGM was assessed using glucose exposures defined as areas under curves (AUCs) and mean glucose values.

RESULTS

Averaged 2-h postprandial glucose value (averaged PPG, mmol/L, mean±SD) and postprandial glucose exposure (AUCpp, mean±SD, mmol·L(-1)·h) were significantly higher in subgroup 2 (mean HbA1c=6.7%, 50mmol/mol) than in subgroup 1 (mean HbA1c=6.0%, 42mmol/mol): averaged PPG=8.1±1.3 versus 7.3±1.3mmol/L (p<0.002); AUCpp=23.5±8.6 versus 16.2±8.6 (p<0.0001). The percentages of persons with averaged PPG≥7.8mmol/L were 52% and 24% (p<0.01) in subgroups 2 and 1, respectively. Similar results were observed in those (subgroups A and B) who were on diet alone.

CONCLUSIONS

The residual dysglycemia in type 2 diabetes with HbA1c between 6.5 and 6.9% (48-52mmol/mol) inclusive is mainly due to remnant abnormal postprandial glucose excursions. Consequently, HbA1c<6.5% (48mmol/mol) is an achievable goal with therapeutic measures aimed at reducing postmeal glucose when the HbA1c is at 7% (53mmol/mol).

Suppressors of cytokine signaling (SOCS) and type 2 diabetes

The suppressors of cytokine signaling (SOCS) proteins are originally identified as negative regulators of cytokine-activated Janus kinase/signal transducers and activators of transcription signaling pathway, but increasing evidence reveals that SOCS proteins play an important role in the development of type 2 diabetes involving regulation of the insulin signaling and pancreatic β-cell function, and that SOCS are promising to be the targets for the treatment of type 2 diabetes. In this review, we focus on the emerging role for SOCS and the potential drugs targeting SOCS for type 2 diabetes.

Study of postprandial lipaemia in type 2 diabetes mellitus: exenatide versus liraglutide

Therapeutic approaches based on the actions of the incretin hormone GLP-1 have been widely established in the management of T2DM. Nevertheless, much less research has been aimed at elucidating the role of GLP-1 in lipid metabolism and in particular postprandial dyslipidemia. Exenatide and liraglutide are two GLP-1 receptor agonists which are currently available as subcutaneously administered treatment for T2DM but their chronic effects on postprandial lipaemia have not been well investigated. The aim of this study is to examine the effect of treatment with either liraglutide or exenatide for two weeks on postprandial lipaemia in obese subjects with T2DM. This study was a single-center, two-armed, randomized, controlled 2-week prospective intervention trial in 20 subjects with T2DM. Patients were randomized to receive either liraglutide or exenatide treatment and underwent a standardized meal tolerance test early in the morning after 10 h fast at baseline (visit 1, beginning of treatment) and after a two-week treatment period (visit 2). Exenatide and liraglutide both appear to be equally effective in lowering postprandial lipaemia after the first administration and after a two-week treatment. The mechanisms which lead to this phenomenon, which seem to be independent of gastric emptying, are yet to be studied.