Angiogenesis-related ultrastructural changes to capillaries in human skeletal muscle in response to endurance exercise

Baum, Oliver; Gübeli, Jennifer; Frese, Sebastian; Torchetti, Eleonora; Malik, Corinna; Odriozola Quesada, Adolfo; Graber, Franziska; Hoppeler, Hans-Heinrich; Tschanz, Stefan A. (2015). Angiogenesis-related ultrastructural changes to capillaries in human skeletal muscle in response to endurance exercise. Journal of applied physiology, 119(10), pp. 1118-1126. American Physiological Society 10.1152/japplphysiol.00594.2015

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The ultrastructure of capillaries in skeletal muscle was morphometrically assessed in vastus lateralis muscle (VL) biopsies taken before and after exercise from 22 participants of two training studies. In study 1 (8 wk of ergometer training), light microscopy revealed capillary-fiber (C/F) ratio (+27%) and capillary density (+16%) to be higher (P ≤ 0.05) in postexercise biopsies than in preexercise biopsies from all 10 participants. In study 2 (6 mo of moderate running), C/F ratio and capillary density were increased (+23% and +20%; respectively, P ≤ 0.05) in VL biopsies from 6 angiogenesis responders (AR) after training, whereas 6 nonangiogenesis responders (NR) showed nonsignificant changes in these structural indicators (-4%/-4%, respectively). Forty capillary profiles per participant were evaluated by point and intersection counting on cross sections after transmission electron microscopy. In study 1, volume density (Vv) and mean arithmetic thickness (T) of endothelial cells (ECs; +19%/+17%, respectively) and pericytes (PCs; +20%/+21%, respectively) were higher (P ≤ 0.05), whereas Vv and T of the pericapillary basement membrane (BM) were -23%/-22% lower (P ≤ 0.05), respectively, in posttraining biopsies. In study 2, exercise-related differences between AR and NR-groups were found for Vv and T of PCs (AR, +26%/+22%, respectively, both P ≤ 0.05; NR, +1%/-3%, respectively, both P > 0.05) and BM (AR, -14%/-13%, respectively, both P ≤ 0.05; NR, -9%/-11%, respectively, P = 0.07/0.10). Vv and T of ECs were higher (AR, +16%/+18%, respectively; NR, +6%/+6%, respectively; all P ≤ 0.05) in both groups. The PC coverage was higher (+13%, P ≤ 0.05) in VL biopsies of individuals in the AR group but nonsignificantly altered (+3%, P > 0.05) in those of the NR group after training. Our study suggests that intensified PC mobilization and BM thinning are related to exercise-induced angiogenesis in human skeletal muscle, whereas training per se induces EC-thickening.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy
04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Anatomy > Functional Anatomy
09 Interdisciplinary Units > Microscopy Imaging Center MIC

UniBE Contributor:

Baum, Oliver; Odriozola Quesada, Adolfo; Graber, Franziska; Hoppeler, Hans-Heinrich and Tschanz, Stefan A.

Subjects:

600 Technology > 610 Medicine & health

ISSN:

8750-7587

Publisher:

American Physiological Society

Language:

English

Submitter:

Benoît Zuber

Date Deposited:

09 Feb 2016 11:45

Last Modified:

18 Sep 2016 02:30

Publisher DOI:

10.1152/japplphysiol.00594.2015

PubMed ID:

26384412

Uncontrolled Keywords:

capillary; electron microscopy; morphometry; skeletal muscle biopsies

BORIS DOI:

10.7892/boris.75241

URI:

https://boris.unibe.ch/id/eprint/75241

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