Microheterogeneity of regional myocardial blood flows in low-perfused rat hearts evaluated by double-tracer digital radiography

Rhodamine 800 as a near-infrared fluorescent deposition flow tracer in rodent hearts

“…16 In comparison, 20% 3 HDMI was lost from the myocardium at 3-min post-injection. 15 A good linear correlation (R = 0.9) between the amounts of Rhod800 loaded to the hearts and recovered from the same hearts also confirmed that the dye retention was proportional to the perfusate volume. A deviation of the apparent correlation factor from the unity was likely due to the unavoidable dye loss during recovery of this hydrophobic dye from the tissue as well as during heart loading.…”

“…15 To achieve a high spatial resolution and avoid the radiation hazard, it is desirable to investigate other perfusion imaging techniques using flow-dependent nonradioactive molecular tracers. We have previously studied interaction of a fluorescent dye, Rhodamine 800, (Rhod800, also known as MitoFluor Far Red 680) with the isolated mitochondria, cells, and rat hearts by diffuse reflectance spectroscopy.…”

Effects of hypoxia on coronary microcirculation during postnatal development

“…Similarly, myocardial lowfl ow perfusion or hypoxia has been shown to decrease spatial blood fl ow heterogeneity, suggesting a mechanism for more effi cient oxygen delivery to the myocardial regions in response to decreased oxygen supply. 18,19 Both increased workload and decreased oxygen supply are considered to induce vascular adaptation processes for more homogenous regional blood fl ow to reduce mismatch between oxygen supply and consumption (i.e., intracellular dysoxia). Metabolically, Ince et al have demonstrated, using an NADH fl uorescence image technique, that the NADH/NAD + redox state (an indicator of the balance between oxygen supply and consumption) exhibited a large increase in its spatial heterogeneity during the conditions of reoxygenation after hypoxia or increased heart rate and that the heterogeneity pattern of NADH fl uorescence was similar in both conditions, 20 suggesting that at the capillary level, there are certain areas (called "microcirculatory weak units") predisposed to become dysoxic fi rst when exposed to decreased oxygen supply or increased oxygen demand.…”