Effects of variations in intragastric volume on blood pressure and splanchnic blood flow during intraduodenal glucose infusion in healthy older subjects

Abstract

(BP) is triggered by the interaction of nutrients with the small intestine and associated with an increase in splanchnic blood flow. Gastric distension may attenuate the postprandial fall in BP. The aim of this study was to determine the effects of differences in intragastric volume, including distension at a low (100 ml) volume, on BP and superior mesenteric artery (SMA) blood flow responses to intraduodenal glucose in healthy older subjects. BP and heart rate (HR; automated device), SMA blood flow (Doppler ultrasound), mesenteric vascular resistance (MVR), and plasma norepinephrine of nine male subjects (65-75 yr old) were measured after an overnight fast on 4 separate days in random order. On each day, subjects were intubated with a nasoduodenal catheter, incorporating a duodenal infusion port, and orally with a second catheter, incorporating a barostat bag, positioned in the fundus. Each subject received a 60-min (t ϭ 0 -60 min) intraduodenal glucose infusion (3 kcal/min) and gastric distension at a volume of 1) 0 ml (V0), 2) 100 ml (V100), 3) 300 ml (V300), or 4) 500 ml (V500). Systolic BP fell (P Ͻ 0.05) during V0, but not during V100, V300, or V500. In contrast, HR (P Ͻ 0.01) and SMA blood flow (P Ͻ 0.001) increased and MVR decreased (P Ͻ 0.05) comparably on all 4 days. Plasma norepinephrine rose (P Ͻ 0.01) in response to intraduodenal glucose, with no difference between the four treatments. There was a relationship between the areas under the curve for the change in systolic BP from baseline with intragastric volume (r ϭ 0.60, P Ͻ 0.001). In conclusion, low-volume (Յ100 ml) gastric distension has the capacity to abolish the fall in BP induced by intraduodenal glucose in healthy older subjects without affecting SMA blood flow or MVR. These observations support the concept that nonnutrient gastric distension prior to a meal has potential therapeutic applications in the management of postprandial hypotension.barostat; distension; postprandial hypotension POSTPRANDIAL HYPOTENSION is an important clinical problem, particularly in the elderly (17,27). It is distinct from, and may occur more frequently than, orthostatic hypotension and represents a substantial cause of morbidity and mortality (17). While the mechanisms underlying postprandial hypotension are poorly defined, several interrelated factors, including meal composition, gastric distension, the rate of small intestinal nutrient delivery, changes in splanchnic blood flow, and neural and hormonal mechanisms, have been identified (17, 39). In the elderly, it is likely that "normality" and postprandial hypotension represent a continuum, as is the case with many age-related phenomena. For example, after an oral glucose load, systolic blood pressure predictably falls in healthy older, but not young, subjects, and in the elderly the magnitude of this decrease is variable (18).Our previous studies established that, in healthy older subjects and patients with type 2 diabetes, the magnitude of the fall in blood pressure in response to enteral glucose is depend...

Postprandial hypotension in older adults: Can it be prevented by drinking water before the meal?

“…In agreement with our results, a previous study observed no significant changes in SBP compared to baseline levels but a small drop in DBP after a breakfast meal plus water ingestion (350 mL) at a comparable composition (63% carbohydrates, 27% fat and 10% proteins) and energy content (1301 kJ) [19]. Our observation of a water-induced attenuation of the postprandial decrease in blood pressure is further supported by a study where gastric distension raised volume dependent blood pressure variables during intraduodenal glucose infusion [20]. Taken together, in response to the higher water drink volume, we observed an attenuation of the decrease in SBP by 3.1 mmHg compared to the lower drink volume.…”

Development of a Whole-Body Physiologically Based Pharmacokinetic Approach to Assess the Pharmacokinetics of Drugs in Elderly Individuals

“…Alterations in perfusion of the stomach, pancreas and spleen could also be captured by this method. The ratio of splanchnic blood flow to CO gradually decreased from 22.5 % in adults to 17.5 % during the tenth decade of life [114–117]. …”

Gastric emptying and glycaemia in health and diabetes mellitus

“…Abbreviations: CCK, cholecystokinin; GIP, gastric inhibitory polypeptide; GLP-1, glucagon-like peptide 1; PYY, peptide YY. administered to healthy individuals 50,64 and patients with T2DM 47 demonstrated a nonlinear glycaemic response, such that the low infusion rate of 1 kcal/min was associated with minimal glycaemic excursions when compared with higher infusion rates (2-4 kcal/min). In complementary studies, the effects of variation of the initial rates of glucose delivery to the small intestine were investigated by delivering an equivalent glucose load either as a constant infusion or with an early high rate of glucose delivery followed by a low rate of glucose infusion.…”

“…71 Additionally, a number of studies have reported that although GIP is the major contributor to the incretin effect when the rate of gastric emptying is ≤2 kcal/min, the effects of GLP-1 are dominant when the rate of gastric emptying is ≥3 kcal/min. 40,41,63,64 Effect of glycaemia on gastric emptying Alterations in glycaemia can induce reversible changes in the rate of gastric emptying. Acute hyperglycaemia is associated with a reduction in fundic tone and antral contractions, as well as stimulation of pyloric contractions and dysregulation of antroduodenal function, which leads to reversible slowing of gastric emptying.…”