Microvascular blood flow changes of the abductor pollicis brevis muscle during sustained static exercise

Martina Giovannella; Evelina Urtane; Marta Zanoletti; Umut Karadeniz; Uldis Rubins; Udo M Weigel; Zbignevs Marcinkevics; Turgut Durduran

doi:10.1364/BOE.427885

Microvascular blood flow changes of the abductor pollicis brevis muscle during sustained static exercise

Biomed Opt Express. 2021 Jun 18;12(7):4235-4248. doi: 10.1364/BOE.427885. eCollection 2021 Jul 1.

Authors

Martina Giovannella¹, Evelina Urtane², Marta Zanoletti¹, Umut Karadeniz¹, Uldis Rubins³, Udo M Weigel⁴, Zbignevs Marcinkevics², Turgut Durduran^{1

5}

Affiliations

¹ ICFO-Institut de Ciències Fotòniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain.
² Faculty of Biology, Department of Human and Animal Physiology, University of Latvia, Kronvalda Blvd. 4, LV 1586, Riga, Latvia.
³ Institute of Atomic Physics and Spectroscopy, University of Latvia, 19 Rainis Blvd., Riga LV- 1586, Latvia.
⁴ HemoPhotonics S.L., Av. Carl Friedrich Gauss Num. 3, 08860 Castelldefels (Barcelona), Spain.
⁵ Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain.

Abstract

A practical assessment of the general health and microvascular function of the palm muscle, abductor pollicis brevis (APB), is important for the diagnosis of different conditions. In this study, we have developed a protocol and a probe to study microvascular blood flow using near-infrared diffuse correlation spectroscopy (DCS) in APB during and after thumb abduction at 55% of maximum voluntary contraction (MVC). Near-infrared time resolved spectroscopy (TRS) was also used to characterize the baseline optical and hemodynamic properties. Thirteen (n=13) subjects were enrolled and subdivided in low MVC (N=6, MVC<2.3 kg) and high MVC (N=7, MVC≥2.3 kg) groups. After ruling out significant changes in the systemic physiology that influence the muscle hemodynamics, we have observed that the high MVC group showed a 56% and 36% decrease in the blood flow during exercise, with respect to baseline, in the long and short source-detector (SD) separations (p=0.031 for both). No statistical differences were shown for the low MVC group (p=1 for short and p=0.15 for long SD). These results suggest that the mechanical occlusion, due to increased intramuscular pressure, exceeded the vasodilation elicited by the higher metabolic demand. Also, blood flow changes during thumb contraction negatively correlated (R=-0.7, p<0.01) with the absolute force applied by each subject. Furthermore, after the exercise, muscular blood flow increased significantly immediately after thumb contractions in both high and low MVC groups, with respect to the recorded values during the exercise (p=0.031). An increase of 251% (200%) was found for the long (short) SD in the low MVC group. The high MVC groups showed a significant 90% increase in blood flow only after 80 s from the start of the protocol. For both low and high MVC groups, blood flow recovered to baseline values within 160 s from starting the exercise. In conclusion, DCS allows the study of the response of a small muscle to static exercise and can be potentially used in multiple clinical conditions scenarios for assessing microvascular health.