Insulin-induced changes in microvascular vasomotion and capillary recruitment are associated in humans.
OBJECTIVE
Insulin-induced capillary recruitment is considered a significant regulator of overall insulin-stimulated glucose uptake. Insulin's action to recruit capillaries has been hypothesized to involve insulin-induced changes in vasomotion. Data directly linking vasomotion to capillary perfusion, however, are presently lacking. We, therefore, investigated whether insulin's actions on capillary recruitment and vasomotion were interrelated in a group of healthy individuals. We further assessed the role of capillary recruitment in the association between vasomotion and insulin-mediated glucose uptake.


METHODS
Changes in vasomotion and capillary density were determined by LDF and capillary videomicroscopy in skin, respectively, before and during a hyperinsulinemic euglycemic clamp in 19 healthy volunteers.


RESULTS
Insulin-induced increase in the neurogenic vasomotion domain was positively related to insulin-augmented capillary recruitment (r = 0.51, p = 0.04), and both parameters were related to insulin-mediated glucose uptake (r = 0.47, p = 0.06 and r = 0.73, p = 0.001, respectively). The change in insulin-augmented capillary recruitment could, at least statistically, largely explain the association between the neurogenic domain and insulin-mediated glucose uptake.


CONCLUSIONS
Insulin-induced changes in vasomotion and capillary recruitment are associated in healthy volunteers. These data suggest that insulin's action to recruit capillaries may in part involve action on the neurogenic vasomotion domain, thereby enhancing capillary perfusion and glucose uptake.
Department of Internal Medicine, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, Amsterdam, The Netherlands.
Michiel P
MP
de Boer
Rick I
RI
Meijer
John
J
Newman
Coen D A
CD
Stehouwer
Etto C
EC
Eringa
Yvo M
YM
Smulders
Erik H
EH
Serné
D000328:Adult; D002196:Capillaries / Q000502:physiology*; D005947:Glucose / Q000378:metabolism*; D006439:Hemodynamics / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D008297:Male
D007004:Hypoglycemic Agents; D007328:Insulin; D005947:Glucose
capillary recruitment; insulin sensitivity; vasomotion