Premium
Peri‐Capillary Pericytes are Associated with Capillary De‐Recruitment in the Setting of Non‐Critical Stenosis
Author(s) -
Methner Carmen,
Iliff Jeffrey,
Alkayed Nabil,
Kaul Sanjiv
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.831.9
Subject(s) - microangiography , constriction , stenosis , capillary action , perfusion , microcirculation , adenosine , cardiology , medicine , reactive hyperemia , chemistry , blood flow , anatomy , materials science , composite material
Capillary de‐recruitment distal to a coronary stenosis has been implicated as the mechanism of reversible perfusion defect during coronary hyperemia. However, direct visualization of this phenomenon has not been observed in vivo, and mechanisms underlying capillary de‐recruitment are not defined. Capillary pericytes were recently suggested to regulate capillary diameter and blood flow; however those findings have been controversial. We tested whether capillary de‐recruitment occurs during hyperemic challenge induced by adenosine under conditions of non‐critical stenosis, and investigated the role of pericytes in regulating microvascular perfusion through local constriction of capillaries. Non‐critical stenosis was produced in the femoral artery using “needle over artery” approach in NG2‐DsRed mice (n=24). Changes in capillary diameter and flux were assessed 5 min before and 10 min after adenosine application (6 mM, topical administration at the stenosis site) using in vivo two‐photon microscopy and optical microangiography (OMAG). Adenosine application during stenosis resulted in a reduction in the mean change in capillary diameter (100.7%±1.2% of baseline in control and 98.1%±0.8% in the stenosis group (n= 12 animals per group, with 15–16 capillaries per animal, p<0.05, figure A)). Furthermore, the proportion of constricting capillaries increased from 19.0%±3.1% (n=12) under control conditions to 31.8%±3.8% during stenosis (n=12, p<0.05, figure B). Capillaries with associated pericytes were more prone to constriction, while capillaries without pericytes showed no change in capillary diameter (101.3%±1.7% of baseline in control and 98.6%±1.0% in the stenosis group (n= 12 animals per group, with 4–6 capillaries with associated pericytes per animal, p<0.05). Our results illustrate direct visualization and quantification of capillary de‐recruitment distal to skeletal muscle artery stenosis during hyperemia. In addition this study provides in vivo evidence that the presence of pericytes on capillaries is associated with capillary constriction under conditions of non‐critical stenosis. This is important because changes in capillary diameter influence erythrocyte flux and tissue oxygen delivery.A: Histogram of percent diameter change relative to baseline for control and stenosis animals. B: Percentage of capillaries constricting (>5% decrease in capillary diameter compared to baseline), dilating (>5% increase) or remaining unchanged (<5% change).