Gastric emptying in health and type 2 diabetes: An evaluation using a 75 g oral glucose drink

Designer GLP1 poly-agonist peptides in the management of diabesity

INTRODUCTION

To date, the 21^st Century has witnessed key developments in the management of diabesity (a conflation of obesity and Type 2 Diabetes Mellitus [T2D]), including Glucagon Like Peptide 1 (GLP1) receptor agonist therapies, and recently the 'designer' GLP1 Poly-agonist Peptides (GLP1PPs).

AREAS COVERED

A PubMed search of published data on the GLP1PP class of therapies was conducted. The gut-brain axis forms complex multi-directional interlinks that include autonomic nervous signaling, components of the gut microbiota (including metabolic by-products and gram-negative cell wall components [e.g. endotoxinaemia]), and incretin hormones that are secreted from the gut in response to the ingestion of nutrients. The development of dual-incretin agonist therapies includes combinations of the GLP1 peptide with Glucose-dependent Insulinotropic Polypeptide (GIP), Glucagon (Gcg), Cholecystokinin (CCK), Peptide YY (PYY), and Glucagon-Like Peptide 2 (GLP2). Triple incretin agonist therapies are also under development.

EXPERT OPINION

At the dawn of a new era in the therapeutic management of diabesity, the designer GLP1PP class holds great promise, with each novel combination building on a preexisting palimpsest of clinical data and insights. Future innovations of the GLP1PP class will likely enable medically induced weight loss and glycemic control in diabesity to rival or even out-perform those resulting from bariatric surgery.

Determinants of blood glucose concentrations following a high carbohydrate meal in type 2 diabetes: A multiple linear regression analysis

This study showed that in relatively well-controlled type 2 diabetes blood glucose levels after a high carbohydrate meal were associated positively with fasting blood glucose, but also positively with gastric emptying in the first hour and negatively with the increments in plasma glucagon-like peptide-1 (GLP-1) in the later postprandial phase.

The 'early' postprandial glucagon response is related to the rate of gastric emptying in type 2 diabetes

Gastric emptying (GE) is a major determinant of the postprandial glycemic and insulinemic responses in health and type 2 diabetes (T2D). However, the effect of GE on the postprandial glucagon response, which is characteristically augmented in T2D, is unknown. This study examined the relationship between plasma glucagon and GE of a standardized mixed meal in individuals with well-controlled T2D. 89 individuals with T2D (HbA1c 6.6 ± 0.1%) consumed a mashed potato meal labeled with 100 µL ¹³C-octanoic acid between 0 and 5 min. Venous blood was sampled frequently over 4 h for measurements of blood glucose and plasma glucagon. The gastric half-emptying time (T50) was calculated by quantification of ¹³C in the breath. Blood glucose peaked at t = 90 min after the meal. Plasma glucagon increased to a peak at t = 30 min and then decreased to a nadir at t = 180 min. The T50 was 68.3 ± 1.6 min. The incremental area under the plasma glucagon curve between t = 0-30 min (glucagon iAUC_0-30 min) was related inversely to the T50 (r = -0.23, P = 0.029), while the increase in blood glucose at t = 30 min was related directly to the plasma glucagon iAUC_0-30 min (r = 0.25, P = 0.018). Accordingly, individuals with relatively faster GE exhibited higher postprandial glucagon and glucose levels (ANOVA: P<0.01 for each). In well-controlled T2D, the early postprandial glucagon response to a mixed meal is related to the rate of GE, and predictive of the initial glycemic response. These observations suggest that a reduction in plasma glucagon may contribute to the effect of dietary and pharmacological strategies which reduce postprandial glycemia in T2D by slowing GE.

Normal and disordered gastric emptying in diabetes: recent insights into (patho)physiology, management and impact on glycaemic control

Gastric emptying is a major determinant of postprandial blood glucose, accounting for ~35% of variance in peak glucose in both healthy individuals and those with type 2 diabetes. Gastric emptying is frequently disordered in individuals with diabetes (both abnormally delayed and accelerated). Delayed gastric emptying, i.e. diabetic gastroparesis, may be linked to upper gastrointestinal symptoms for which current treatment remains suboptimal; pharmacological acceleration of delayed emptying is only weakly associated with symptom improvement. Accordingly, the relationship between symptoms and delayed gastric emptying is not simply 'cause and effect'. In insulin-treated patients, disordered gastric emptying, even when not associated with gastrointestinal symptoms, can cause a mismatch between the onset of insulin action and the availability of absorbed carbohydrate, leading to suboptimal glycaemic control. In patients with type 2 diabetes, interventions that slow gastric emptying, e.g. glucagon-like peptide-1 receptor agonists, reduce postprandial blood glucose. This review focuses on recent insights into the impact of gastric emptying on postprandial blood glucose, effects of diabetes therapy on gastric emptying and the management of disordered gastric emptying in diabetes. In view of the broad relevance of gastric emptying to diabetes management, it is important that future clinical trials evaluating novel therapies that may affect gastric emptying should quantify the latter with an appropriate technique, such as scintigraphy or a stable isotope breath test.

Plasma GLP-1 Response to Oral and Intraduodenal Nutrients in Health and Type 2 Diabetes-Impact on Gastric Emptying

CONTEXT

Both gastric emptying and the secretion of glucagon-like peptide-1 (GLP-1) are major determinants of postprandial glycemia in health and type 2 diabetes (T2D). GLP-1 secretion after a meal is dependent on the entry of nutrients into the small intestine, which, in turn, slows gastric emptying.

OBJECTIVE

To define the relationship between gastric emptying and the GLP-1 response to both oral and small intestinal nutrients in subjects with and without T2D.

METHODS

We evaluated: (i) the relationship between gastric emptying (breath test) and postprandial GLP-1 levels after a mashed potato meal in 73 individuals with T2D; (ii) inter-individual variations in GLP-1 response to (a) intraduodenal glucose (4 kcal/min) during euglycemia and hyperglycemia in 11 healthy and 12 T2D, subjects, (b) intraduodenal fat (2 kcal/min) in 15 T2D subjects, and (c) intraduodenal protein (3 kcal/min) in 10 healthy subjects; and (iii) the relationship between gastric emptying (breath test) of 75 g oral glucose and the GLP-1 response to intraduodenal glucose (4 kcal/min) in 21 subjects (9 healthy, 12 T2D).

RESULTS

The GLP-1 response to the mashed potato meal was unrelated to the gastric half-emptying time (T50). The GLP-1 responses to intraduodenal glucose, fat, and protein varied substantially between individuals, but intra-individual variation to glucose was modest. The T50 of oral glucose was related directly to the GLP-1 response to intraduodenal glucose (r = 0.65, P = 0.002).

CONCLUSION

In a given individual, gastric emptying is not a determinant of the postprandial GLP-1 response. However, the intrinsic gastric emptying rate is determined in part by the responsiveness of GLP-1 to intestinal nutrients.

Impact of diabetes mellitus on in-hospital mortality in adult patients with COVID-19: a systematic review and meta-analysis

BACKGROUND

The novel coronavirus disease 2019 (COVID-19) has spread worldwide since the beginning of 2020, placing the heavy burden on the health systems all over the world. The population that particularly has been affected by the pandemic is the group of patients suffering from diabetes mellitus. Having taken the public health in considerations, we have decided to perform a systematic review and meta-analysis of diabetes mellitus on in-hospital mortality in patients with COVID-19.

METHODS

A systematic literature review (MEDLINE, EMBASE, Web of Science, Scopus, Cochrane) including all published clinical trials or observational studies published till December 10, 2020, was performed using following terms "diabetes mellitus" OR "diabetes" OR "DM" AND "survival" OR "mortality" AND "SARS-CoV-2" OR "COVID-19".

RESULTS

Nineteen studies were included out of the 7327 initially identified studies. Mortality of DM patients vs non-DM patients was 21.3 versus 6.1%, respectively (OR = 2.39; 95%CI: 1.65, 3.64; P < 0.001), while severe disease in DM and non-DM group varied and amounted to 34.8% versus 22.8% (OR = 1.43; 95%CI: 0.82, 2.50; P = 0.20). In the DM group, the complications were observed far more often when compared with non-DM group, both in acute respiratory distress (31.4 vs. 17.2%; OR = 2.38; 95%CI:1.80, 3.13; P < 0.001), acute cardiac injury (22.0% vs. 12.8%; OR = 2.59; 95%CI: 1.81, 3.73; P < 0.001), and acute kidney injury (19.1 vs. 10.2%; OR = 1.97; 95%CI: 1.36, 2.85; P < 0.001).

CONCLUSIONS

Based on the findings, we shall conclude that diabetes is an independent risk factor of the severity of COVID-19 in-hospital settings; therefore, patients with diabetes shall aim to reduce the exposure to the potential infection of COVID-19.

The 1-Hour Plasma Glucose: Common Link Across the Glycemic Spectrum

Evidence from populations at risk for type 1 diabetes, type 2 diabetes or gestational diabetes substantiates the 1-hour plasma glucose as a sensitive alternative marker for identifying high-risk individuals when ß-cell function is relatively more functional. An elevated 1-hour plasma glucose could therefore diagnose dysglycemia and risk for complications across the glycemic spectrum. Reducing the 2-hour oral glucose tolerance test to 1-hour would reduce the burden on patients, likely reduce costs, and enhance its accessibility in practice.