Non-invasive determination of blood input function to compute rate of myocardial glucose uptake from dynamic FDG PET images of rat heart in vivo: comparative study between the inferior vena cava and the left ventricular blood pool with spill over and partial volume corrections

Serotonin [5-hydroxytryptamine (5-HT)] causes relaxation of the isolated superior mesenteric vein, a splanchnic blood vessel, through activation of the 5-HT7 receptor. As part of studies designed to identify the mechanism(s) through which chronic (≥24 h) infusion of 5-HT lowers blood pressure, we tested the hypothesis that 5-HT causes in vitro and in vivo splanchnic venodilation that is 5-HT7 receptor dependent. In tissue baths for measurement of isometric contraction, the portal vein and abdominal inferior vena cava relaxed to 5-HT and the 5-HT1/7 receptor agonist 5-carboxamidotryptamine; relaxation was abolished by the 5-HT7 receptor antagonist SB-269970. Western blot analyses showed that the abdominal inferior vena cava and portal vein express 5-HT7 receptor protein. In contrast, the thoracic vena cava, outside the splanchnic circulation, did not relax to serotonergic agonists and exhibited minimal expression of the 5-HT7 receptor. Male Sprague-Dawley rats with chronically implanted radiotelemetry transmitters underwent repeated ultrasound imaging of abdominal vessels. After baseline imaging, minipumps containing vehicle (saline) or 5-HT (25 μg·kg−1·min−1) were implanted. Twenty-four hours later, venous diameters were increased in rats with 5-HT-infusion (percent increase from baseline: superior mesenteric vein, 17.5 ± 1.9; portal vein, 17.7 ± 1.8; and abdominal inferior vena cava, 46.9 ± 8.0) while arterial pressure was decreased (~13 mmHg). Measures returned to baseline after infusion termination. In a separate group of animals, treatment with SB-269970 (3 mg/kg iv) prevented the splanchnic venodilation and fall in blood pressure during 24 h of 5-HT infusion. Thus, 5-HT causes 5-HT7 receptor-dependent splanchnic venous dilation associated with a fall in blood pressure. NEW & NOTEWORTHY This research is noteworthy because it combines and links, through the 5-HT7 receptor, an in vitro observation (venorelaxation) with in vivo events (venodilation and fall in blood pressure). This supports the idea that splanchnic venodilation plays a role in blood pressure regulation.

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In vivo magnetic particle imaging: angiography of inferior vena cava and aorta in rats using newly developed multicore particles

Scientific Reports ◽

10.1038/s41598-020-74151-4 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Azadeh Mohtashamdolatshahi ◽

Harald Kratz ◽

Olaf Kosch ◽

Ralf Hauptmann ◽

Nicola Stolzenburg ◽

...

Keyword(s):

Image Quality ◽

Inferior Vena Cava ◽

Temporal Resolution ◽

Magnetic Particle ◽

Inferior Vena ◽

Vena Cava ◽

High Temporal Resolution ◽

Magnetic Particle Imaging ◽

Particle Imaging

Abstract Magnetic Particle Imaging (MPI) is a new imaging modality, which maps the distribution of magnetic nanoparticles (MNP) in 3D with high temporal resolution. It thus may be suited for cardiovascular imaging. Its sensitivity and spatial resolution critically depend on the magnetic properties of MNP. Therefore, we used novel multicore nanoparticles (MCP 3) for in-vivo MPI in rats and analyzed dose requirements, sensitivity and detail resolution. 8 rats were examined using a preclinical MPI scanner (Bruker Biospin GmbH, Germany) equipped with a separate receive coil. MCP 3 and Resovist were administered intravenously (i.v.) into the rats’ tail veins at doses of 0.1, 0.05 and 0.025 mmol Fe/kg followed by serial MPI acquisition with a temporal resolution of 46 volumes per second. Based on a qualitative visual scoring system MCP 3–MPI images showed a significantly (P ≤ 0.05) higher image quality than Resovist-MPI images. Morphological features such as vessel lumen diameters (DL) of the inferior vena cava (IVC) and abdominal aorta (AA) could be assessed along a 2-cm segment in mesenteric area only after administration of MCP 3 at dosages of 0.1, 0.05 mmol Fe/kg. The mean DL ± SD estimated was 2.7 ± 0.6 mm for IVC and 2.4 ± 0.7 mm for AA. Evaluation of DL of the IVC and AA was not possible in Resovist-MPI images. Our results show, that MCP 3 provide better image quality at a lower dosage than Resovist. MCP 3-MPI with a clinically acceptable dose of 0.05 mmol Fe/kg increased the visibility of vessel lumens compared to Resovist-based MPI towards possible detection of vascular abnormalities such as stenosis or aneurysms, in vivo.

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Mechanism of hemodynamic responses to occlusion of the descending thoracic aorta

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1980.238.4.h423 ◽

1980 ◽

Vol 238 (4) ◽

pp. H423-H429 ◽

Cited By ~ 7

Author(s):

O. Stokland ◽

M. M. Miller ◽

A. Ilebekk ◽

F. Kiil

Keyword(s):

Inferior Vena Cava ◽

Superior Vena Cava ◽

Inferior Vena ◽

Superior Vena ◽

Vena Cava ◽

Spinal Column ◽

Left Ventricular Pressure ◽

Left Ventricular ◽

Aortic Occlusion ◽

Systolic Volume

To examine left ventricular responses to aortic occlusion, changes in end-diastolic volume (EDV) and end-systolic volume (ESV) were estimated by ultrasonic recordings of myocardial distances in atropinized open-chest dogs. During aortic occlusion EDV and ESV increased equally, systolic left ventricular pressure (LVP) rose by 86 +/- 8 mmHg, and blood flow more than doubled in the superior vena cava and fell by 90% in the inferior vena cava. During combined occlusion of aorta and inferior vena cava, systolic LVP and superior vena cava flow did not rise above control and EDV declined. By infusing 25 +/- 2 ml/kg body wt of blood during combined occlusion, the effects of aortic occlusion could be reproduced; control values before blood infusion were reestablished by withdrawal of only one-third of the infused volume, indicating a shunt line along the spinal column. Thus during aortic occlusion, transfer of blood accounts for the rise in EDV and increased activation of the Frank-Starling mechanism; increased afterload raises ESV as much as EDV in anesthetized dogs not subjected to sympathetic stimulation. Consequently, stroke volume is maintained and systolic LVP increased.

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P1807COMPARISON BETWEEN INFERIOR VENA CAVA DIAMETER, BIOIMPEDANCE SPECTROSCOPY AND CLINICAL CRITERION FOR DRY WEIGHT ESTIMATION IN HEMODIALYZED CHILDREN

Nephrology Dialysis Transplantation ◽

10.1093/ndt/gfaa142.p1807 ◽

2020 ◽

Vol 35 (Supplement_3) ◽

Author(s):

Varvara Askiti ◽

Georgia Malakasioti ◽

George Servos ◽

Georgia Grigoriadou ◽

Andromachi Mitsioni

Keyword(s):

Inferior Vena Cava ◽

Inferior Vena ◽

New Technologies ◽

Fluid Overload ◽

Vena Cava ◽

Dry Weight ◽

Chronic Hemodialysis ◽

Hydration Status ◽

Clinical Criteria

Abstract Background and Aims The determination of dry weight (DW) in children on chronic hemodialysis (HD) remains problematic. No method has been shown superior for DW assessment in the few pediatric studies exploring the utility of inferior vena cava expiratory and inspiratory diameter diameter (IVCDe, IVCDi) and BIS against clinical criteria. We aimed to compare the performance of IVCD, BIS and clinical judgement in DW prediction in hemodialyzed children. Method IVCD and BIS were measured serially pre and post the midweek HD session. IVCDi, IVCDe and IVC contractility index (IVCCI) associations with: (1) BIS estimated (BIS-relOH) and (2) clinically assessed hydration status (OHc) based on deviation from DW were explored. The interpretation of IVC measurements was based on previously published pediatric reference values. The level of agreement between the three tools in fluid overload recognition was studied. Results Fifty-two sets of measurements were undertaken in 13 patients (median age 11 years). OHc and BIS-relOH were positively associated to each other (r=0,5, p<0,05) and to IVCDi (r=0,4, r=0,5, p<0,05) and IVCDe (r=0,4, r=0,6, p<0,05). A negative association between IVCCI and relOH-BIS was observed (r= -0,4, p<0,05). There was a poor agreement between the three methods in identification of fluid overload; out of 28 clinically overloaded patients, BIS identified only 7 whereas IVCD none (Cohen’s k <0). Conclusion IVCD measurements alone are not reliable for accurate fluid status prediction in hemodialyzed children as they seem to underestimate fluid overload compared to BIS and clinical criteria. Further studies are warranted to explore the applicability of new technologies for DW assessment of dialysis patients.

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