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Individual microvascular units are critical to cardiac performance
Author(s) -
Egginton Stuart,
Hauton David,
Winter James,
Evans Rhys D
Publication year - 2013
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.27.1_supplement.898.12
Subject(s) - arteriole , medicine , chemistry , cardiology , endocrinology , microcirculation , postprandial , insulin
High cardiac energy demand relies on lipid & glucose oxidation, depending on oxygen availability. Arteriolar supply is likely critical with loss of metabolic flexibility/rarefaction of capillary supply, e.g. diabetes or hypertension. Random blockade of coronary arterioles by infusion of microspheres decreased rate‐pressure product (RPP; R2=0.82) and peak developed pressure (P<0.01). This decreased RPP by 70% (P<0.001) in control & diabetic perfused‐working hearts. Palmitate oxidation halved (P<0.001) with a similar increase in glucose oxidation (P<0.01) for control hearts, but in diabetic hearts palmitate oxidation was 2.5‐fold higher (P<0.001) with unchanged glucose oxidation (ns). Arteriole occlusion decreased the density of patent capillaries by 40% (P<0.001) and increased capillary supply area by 60% (P<0.01). There was a more heterogeneous distribution of functional capillaries in the myocardium following microsphere infusion (CV=19.15% untreated vs. 25.80% occluded). We suggest that capillary supply is more critical for cardiac mechanical performance than preservation of metabolic flexibility, and supports the importance of preventing arteriole loss as a consequence of microvascular disease.