Greater α1-adrenergic-mediated vasoconstriction in contracting skeletal muscle of patients with type 2 diabetes

Patients with type 2 diabetes mellitus (T2DM) exhibit diminished exercise capacity likely attributable to reduced skeletal muscle blood flow (i.e., exercise hyperemia). A potential underlying mechanism of the impaired hyperemic response to exercise could be inadequate blunting of sympathetic-mediated vasoconstriction (i.e., poor functional sympatholysis). Therefore, we studied the hyperemic and vasodilatory responses to handgrip exercise in patients with T2DM as well as vasoconstriction to selective α-agonist infusion. Forearm blood flow (FBF) and vascular conductance (FVC) were examined in patients with T2DM (n = 30) as well as nondiabetic controls (n = 15) with similar age (59 ± 9 vs. 60 ± 9 yr, P = 0.69) and body mass index (31.4 ± 5.2 vs. 29.5 ± 4.6 kg/m2, P = 0.48). Intra-arterial infusion of phenylephrine (α1-agonist) and dexmedetomidine (α2-agonist) were used to induce vasoconstriction: [(FVCwith drug - FVCpredrug)/FVCpredrug × 100%]. Subjects completed rest and dynamic handgrip exercise (20% of maximum) trials per α-agonist. Patients with T2DM had smaller increases (Δ from rest) in FBF (147 ± 71 vs. 199 ± 63 ml/min) and FVC (126 ± 58 vs. 176 ± 50 ml·min-1·100 mmHg-1, P < 0.01 for both) during exercise compared with controls, respectively. During exercise, patients with T2DM had greater α1- (-16.9 ± 5.9 vs. -11.3 ± 3.8%) and α2-mediated vasoconstriction (-23.5 ± 7.1 vs. -19.0 ± 6.5%, P < 0.05 for both) versus controls. The magnitude of sympatholysis (Δ in %vasoconstriction between exercise and rest) for PE was lower (worse) in patients with T2DM versus controls (14.9 ± 12.2 vs. 23.1 ± 8.1%, P < 0.05) whereas groups were similar during DEX trials (24.6 ± 12.3 vs. 27.6 ± 13.4%, P = 0.47). Our data suggest patients with T2DM have attenuated hyperemic and vasodilatory responses to exercise, which could be attributable to greater α1-mediated vasoconstriction in contracting skeletal muscle.NEW & NOTEWORTHY Findings presented in this article are the first to show patients with type 2 diabetes mellitus have blunted hyperemic and vasodilatory responses to dynamic handgrip exercise. Moreover, we illustrate greater α1-adrenergic-mediated vasoconstriction may contribute to our initial observations. Collectively, these data suggest patients with type 2 diabetes may have impaired functional sympatholysis, which can contribute to their reduced exercise capacity.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:319

Enthalten in:

American journal of physiology. Heart and circulatory physiology - 319(2020), 4 vom: 01. Okt., Seite H797-H807

Sprache:

Englisch

Beteiligte Personen:

Bock, Joshua M [VerfasserIn]
Hughes, William E [VerfasserIn]
Ueda, Kenichi [VerfasserIn]
Feider, Andrew J [VerfasserIn]
Hanada, Satoshi [VerfasserIn]
Kruse, Nicholas T [VerfasserIn]
Iwamoto, Erika [VerfasserIn]
Casey, Darren P [VerfasserIn]

Links:

Volltext

Themen:

α-adrenergic
1WS297W6MV
Adrenergic alpha-1 Receptor Agonists
Blood flow
Diabetes
Exercise
Journal Article
Phenylephrine
Research Support, Non-U.S. Gov't
Vasodilation

Anmerkungen:

Date Completed 24.11.2020

Date Revised 24.11.2020

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1152/ajpheart.00532.2020

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM313959390