Myocardial 99mTc-sestamibi extraction and washout in hypertensive heart failure using an isolated rat heart

Fukushima, Kenji; Momose, Mitsuru; Kondo, Chisato; Higuchi, Takahiro; Kusakabe, Kiyoko; Hagiwara, Nobuhisa

doi:10.1016/j.nucmedbio.2010.07.002

« Previous Next »Nuclear Medicine and Biology
Volume 37, Issue 8 , Pages 1005-1012, November 2010

Myocardial ^99mTc-sestamibi extraction and washout in hypertensive heart failure using an isolated rat heart☆

Kenji Fukushima
- Department of Cardiology, Tokyo Women's Medical University, Tokyo 162-8666, Japan
- Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
Mitsuru Momose
- Department of Diagnostic Imaging and Nuclear Medicine, Tokyo Women's Medical University, Tokyo 162-8666, Japan
- Corresponding author. Tel.: +81 3 3353 8111; fax: +81 3 5269 7531.
Chisato Kondo
- Department of Diagnostic Imaging and Nuclear Medicine, Tokyo Women's Medical University, Tokyo 162-8666, Japan
Takahiro Higuchi
- Department of Radiology, Johns Hopkins University, Baltimore, MD, USA
Kiyoko Kusakabe
- Department of Diagnostic Imaging and Nuclear Medicine, Tokyo Women's Medical University, Tokyo 162-8666, Japan
Nobuhisa Hagiwara
- Department of Cardiology, Tokyo Women's Medical University, Tokyo 162-8666, Japan

Received 27 January 2010; received in revised form 3 June 2010; accepted 3 July 2010. published online 02 September 2010.

Abstract

Purpose

Myocardial mitochondria are the primary part of energy production for healthy cardiac contraction. And mitochondrial dysfunction would play an important role in progressive heart failure. In the recent years, myocardial washout of ^99mTc-sestamibi [(^99mTc-hexakis-2-methoxy-2-methylpropyl isonitrile (MIBI)] has been introduced to be a potential marker in patients with heart failure. The objective of this study was to clarify MIBI extraction and washout kinetics using isolated perfusion system in hypertension induced model of myocardial dysfunction.

Methods

Six-week-old Dahl-salt sensitive rats, allotted to 4 groups; a 5-week high-salt group (5wk-HS), 12-week high-salt group (12wk-HS) and two age-matched, low-salt diet control groups (5wk-LS and 12wk-LS). The rats in 5wk-HS and 12wk-HS groups were fed a high-salt diet (containing 8% NaCl). Cardiac function was examined by echocardiography before removing heart. Hearts were perfused according to the Langendorff method at a constant flow rate, in which 20-min MIBI washin was conducted followed by 25-min MIBI washout. Whole heart radioactivity was collected every sec by an external gamma detector. The myocardial extraction, K₁ (ml/min) and washout rate, k₂ (min⁻¹) were generated.

Results

High-salt diet groups showed significant high-blood pressure. Echocardiography revealed thickened LV walls in 5wk-HS, and reduced cardiac function in 12wk-HS, compared to each age-matched control group. K₁ showed no significant difference among all groups (5wk-HS: 2.36±1.07, 5wk-control: 2.59±0.28, 12wk-HS: 1.91±0.90, and 12wk-control: 2.84±0.57). k₂ in 5wk-HS was comparable to that in the age matched control group (0.00030±0.00039 vs −0.000010±0.00044), but it was increased remarkably in 18wk-HS compared to the age matched control group (0.0025±0.0011 vs 0.000025±0.000041, P<.01), and 5wk-HS (P<.01).

Conclusion

In the course of hypertensive heart disease, MIBI washout was increased in the transitional state from hypertrophied to dilated and failing heart, while MIBI extraction remained intact.

Keywords: ^99mTc-sestamibi, Hypertensive heart failure, Dahl salt-sensitive rat, Myocardial mitochondria, Isolated rat heart

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☆ Statement: We have no financial relationship, and have full control of all primary data. We agree to allow the reviewer to review our data if requested.

PII: S0969-8051(10)00321-5

doi:10.1016/j.nucmedbio.2010.07.002

« Previous Next »Nuclear Medicine and Biology
Volume 37, Issue 8 , Pages 1005-1012, November 2010

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