Potential for Gut Peptide-Based Therapy in Postprandial Hypotension

The postprandial actions of GLP-1 receptor agonists: The missing link for cardiovascular and kidney protection in type 2 diabetes

Recent clinical trials in people with type 2 diabetes have demonstrated beneficial actions on heart and kidney outcomes following treatment with GLP-1RAs. In part, these actions are consistent with improved glucose control and significant weight loss. But GLP-1RAs may also have additive benefits by improving postprandial dysmetabolism. In diabetes, dysregulated postprandial nutrient excursions trigger inflammation, oxidative stress, endothelial dysfunction, thrombogenicity, and endotoxemia; alter hormone levels; and modulate cardiac output and regional blood and lymphatic flow. In this perspective, we explore the actions of GLP-1RAs on the postprandial state and their potential role in end-organ benefits observed in recent trials.

Postprandial Hypotension: An Underreported Silent Killer in the Aged

Orthostatic hypotension (OH) is one of the most common autonomic dysfunctions, with high prevalence in populations of elderly, hypertensive, diabetic, or Parkinson's patients. Evidence is emerging that OH co-occurs with postprandial hypotension (PPH); a greater prevalence of PPH than of OH is reported for Parkinson's disease patients. OH is diagnosed by measuring the blood pressure changes associated with postural changes and often produces alterations in consciousness or other such bothersome symptoms as fainting. PPH is diagnosed by measuring the blood pressure changes associated with ingesting high carbohydrate test meals. Because of the time lag between food ingestion and absorption, PPH is often not reported as symptomatic and, therefore, not diagnosed as PPH. OH and PPH are independent predictors for all causes of mortality. Relative underdiagnosis may qualify PPH as a "silent killer" disease. This review is aimed at providing updates on the epidemiology, pathophysiology, and clinical aspects associated with the diagnosis and treatment of PPH. Highlighting the current gaps in knowledge and research about PPH is expected to make medical practitioners more cognizant of the dangers of underdiagnosis and motivate future research to identify individuals and populations at high risk for PPH and its sequelae.

Systematic review and meta-analysis examining the relationship between postprandial hypotension, cardiovascular events, and all-cause mortality

BACKGROUND

Postprandial hypotension (PPH) has been reported to be associated with syncope, falls, adverse cardiovascular outcomes, and increased all-cause mortality. It has been reported to have an incidence as high as 30% in the elderly and persons with diabetes. We therefore performed a meta-analysis to determine the relation of PPH with cardiovascular disease (CVD) events and all-cause mortality.

OBJECTIVES

Our objective was to conduct a systematic review and meta-analysis of cohort and cross-sectional studies to determine the association of PPH with CVD and all-cause mortality.

METHODS

We searched the databases MEDLINE, EMBASE, and Cochrane library up to 13 April 2022 for prospective cohort and cross-sectional studies that examined the association of PPH with CVD outcomes and all-cause mortality. Data were analyzed using the generic inverse variance method with a random-effects model. Grading of Recommendations, Assessment, Development, and Evaluation approach assessed the certainty of evidence.

RESULTS

Seven studies that included 2389 participants met our inclusion criteria. PPH was associated with each outcome individually, including increased all-cause mortality, total CVD, CVD mortality, and stroke. CVD outcomes and all-cause mortality combined were also associated with PPH (RR: 1.52; 95% CI: 1.05, 2.18; P = 0.03; I2 = 77%). The certainty of evidence was graded as very low due to significant heterogeneity and the limited number of studies.

CONCLUSIONS

This assessment indicates an association of PPH with CVD and all-cause mortality. Further studies are required to improve CVD and mortality estimates, but the potential seriousness of CVD and all-cause mortality as outcomes of PPH justifies more screening, diagnosis, and research.

Role of endogenous incretins in the regulation of postprandial lipoprotein metabolism

OBJECTIVE

Incretins are known to influence lipid metabolism in the intestine when administered as pharmacologic agents. The aggregate influence of endogenous incretins on chylomicron production and clearance is less clear, particularly in light of opposing effects of co-secreted hormones. Here, we tested the hypothesis that physiological levels of incretins may impact on production or clearances rates of chylomicrons and VLDL.

DESIGN AND METHODS

A group of 22 overweight/obese men was studied to determine associations between plasma levels of glucagon-like peptides 1 and 2 (GLP-1 and GLP-2) and glucose-dependent insulinotropic polypeptide (GIP) after a fat-rich meal and the production and clearance rates of apoB48- and apoB100-containing triglyceride-rich lipoproteins. Subjects were stratified by above- and below-median incretin response (area under the curve).

RESULTS

Stratification yielded subgroups that differed about two-fold in incretin response. There were neither differences in apoB48 production rates in chylomicrons or VLDL fractions nor in apoB100 or triglyceride kinetics in VLDL between men with above- vs below-median incretin responses. The men with above-median GLP-1 and GLP-2 responses exhibited higher postprandial plasma and chylomicron triglyceride levels, but this could not be related to altered kinetic parameters. No differences were found between incretin response subgroups and particle clearance rates.

CONCLUSION

We found no evidence for a regulatory effect of endogenous incretins on contemporaneous chylomicron or VLDL metabolism following a standardised fat-rich meal. The actions of incretins at pharmacological doses may not be reflected at physiological levels of these hormones.