Conclusions
Tight quantitative correlation between cardiac (123)I-MIBG uptake and corresponding loss of sympathetic axons in LBD, as established for the first time by this study, provides a scientific basis to confirm the reliability of MIBG cardiac scintigraphy as a powerful clinical tool to detect loss of these axons as a biomarker for the presence of Lewy body disease.
Methods
We collected cardiac tissue samples from 23 patients with autopsy-confirmed LBD and two non-LBD control patients who underwent (123)I-MIBG cardiac scintigraphy in life. Samples of the left ventricular anterior wall were stained with anti-tyrosine hydroxylase (TH) and anti-neurofilament (NF) antibodies as markers of cardiac nerve axons. We quantified the immunolabelled areas and assessed their correlation to standardised heart to mediastinum (H/M) ratios of (123)I-MIBG cardiac scintigraphy.
Results
Cardiac MIBG uptake in the early and delayed phases was reduced in 90.9% and 95.7% of patients with LBD, respectively. The area of TH-immunoreactive axons correlated significantly with the H/M ratio in the early (p=0.036) as well as in the delayed (p=0.018) phases. The area of NF-immunoreactive axons also correlated with the H/M ratio in the early (p=0.003) as well as in the delayed (p=0.001) phases. Conclusions: Tight quantitative correlation between cardiac (123)I-MIBG uptake and corresponding loss of sympathetic axons in LBD, as established for the first time by this study, provides a scientific basis to confirm the reliability of MIBG cardiac scintigraphy as a powerful clinical tool to detect loss of these axons as a biomarker for the presence of Lewy body disease.