Worsening Postural Tachycardia Syndrome Is Associated With Increased Glucose-Dependent Insulinotropic Polypeptide Secretion

Abstract

Background: Postural tachycardia syndrome (POTS) is characterized by excessive upright tachycardia and disabling presyncopal symptoms, which are exacerbated after consuming a high-carbohydrate meal; it is unknown, however, what is the precise underlying mechanism. We seek to investigate the effect of glucose intake on orthostatic hemodynamic changes and gastrointestinal hormone secretion in POTS. Methods: Prospective, case-control study, 12 women with POTS who reported a postprandial worsening of their POTS symptoms and 13 age-matched female controls received 75-g oral glucose and 20 mg/kg acetaminophen to assess nutrient absorption. Hemodynamic, gastrointestinal hormone and acetaminophen levels were measured for up to 120 minutes postingestion while supine and standing. Results: Patients with POTS had significant orthostatic tachycardia, 48.7±11.2 versus 23.3±8.1 bpm, P =0.012 and elevated upright norepinephrine levels, 835.2±368.4 versus 356.9±156.7 pg/mL, P =0.004. After oral glucose, upright heart rate significantly increased in POTS, 21.2±11.9% versus 6.0±19.9%, P =0.033 with a concomitant decline in upright stroke volume, −10.3±11.90% versus 3.3±13.7%, P =0.027; total peripheral resistance, blood pressure and cardiac output remained unaltered. Acetaminophen rate of appearance was similar between groups ( P =0.707), indicating comparable nutrient absorption rates. POTS had increased plasma levels of C-peptide ( P =0.001), GIP (glucose-dependent insulinotropic polypeptide; P =0.001), peptide YY ( P =0.016), and pancreatic polypeptide ( P =0.04) following glucose consumption, but only GIP had a time-dependent association with the worsening upright tachycardia and stroke volume fall. Conclusions: The glucose-induced worsening orthostatic tachycardia in POTS was associated with a decline in SV; these changes occurred while GIP, a splanchnic vasodilator, was maximally elevated.

The importance of glucose‐dependent insulinotropic polypeptide receptor activation for the effects of tirzepatide

“…90 The aforementioned 6-day continuous subcutaneous infusion of GIP in patients with type 1 diabetes resulted in a 12.6% ± 4.2% increase in hepatic lipid content compared with placebo, consistent with earlier proposals of the involvement of GIP in the lipid metabolism. 66 Moreover, levels of endogenous GIP have been linked to various inflammatory processes [91][92][93] and autonomic disturbances of the cardiovascular system, 94 but no causalities have been established. GIP administration also increases the heart rate, which could be a result of changes in the mesenteric blood flow or direct effects on the heart or blood vessels but whether cardiac GIP receptors are present in humans is unknown.…”