Neurological applications for myocardial MIBG scintigraphy

Abstract

Signs or symptoms of impaired autonomic regulation of circulation are typically present in patients affected by Parkinson's disease (PD), in agreement with the cardiac sympathetic denervation discovered by Goldstein more than 15 yrs. ago.In particular, the majority of PD patients have a diffuse left ventricular myocardial sympathetic denervation, being a normal neurological condition present only in a small number of affected subjects. Actually MIBG cardiac imaging is a universally accepted method to estimate cardiac sympathetic innervations. This review covers the role of MIBG cardiac imaging in PD as well as in other parkinsonisms, focusing the attention on technical problems and pathophysiological premises for cardiac denervation. In particular new emerging data support the role of MIBG as biomarker of PD, also before motor symptoms became clinically evident. Therefore the timing of cardiac noradrenergic denervation in PD is a key issue and we want to update the analysis of autonomic cardiovascular abnormalities studied with MIBG in PD and related disorders.

Relationship between the washout rate of I-123 MIBG scans and autonomic function in Parkinson’s disease

“…In PD, a lot of attention has been placed on assessing autonomic failure because clinical signs of related autonomic failure may observe in the early phase of the disease, or even before the onset of the motor symptoms [2][3][4][5]. Metaiodobenzylguanidine (MIBG) is a physiologic analog of guanethidine and its uptake and storage mechanism is similar to that of noradrenaline, which is actively transported into noradrenaline granules in the sympathetic nerve terminals by noradrenaline transport [6]. In general, cardiac uptake in I-123 MIBG cardiac scans is known to decrease in patients with PD, and in one study, decreased myocardial uptake was observed in approximately 90% of patients with PD [7,8].…”

Class-IIa Histone Deacetylase Inhibition Promotes the Growth of Neural Processes and Protects Them Against Neurotoxic Insult

“…Thus, factors that promote dopaminergic neurite growth have the potential to significantly prolong the pre-symptomatic phase of PD. However, as well as the striatal denervation seen in PD [10], there is also cardiac sympathetic denervation [11][12][13] with a common finding being diffuse sympathetic denervation of the left ventricular myocardium [14]. Treatment for PD remains largely limited to dopamine replacement strategies which do not protect against neuronal loss [15].…”

<sup>123</sup>I-Metaiodobenzylguanidine Myocardial Scintigraphy in Lewy Body-Related Disorders: A Literature Review

“…MIBG is a pharmacologically inactive urea derivative that, like noradrenaline, is taken up by adrenergic cells via the human norepinephrine transporter mechanism, stored in vesicles, and secreted in response to a variety of stimuli [ 19 , 22 - 25 ]. Guanethidine may be chemically modified to MIBG [ 26 - 28 ]. MIBG can be labeled with radioactive iodine (most commonly 123 Iodine) to become 123 I-MIBG, and it is taken up by the postganglionic, presynaptic nerve endings [ 1 , 5 , 26 - 28 ].…”

“…Guanethidine may be chemically modified to MIBG [ 26 - 28 ]. MIBG can be labeled with radioactive iodine (most commonly 123 Iodine) to become 123 I-MIBG, and it is taken up by the postganglionic, presynaptic nerve endings [ 1 , 5 , 26 - 28 ]. Radiolabeled MIBG is considered an established sympathetic neuron imaging agent that is useful to study organs that are richly innervated by the sympathetic nervous system [ 1 , 5 , 27 , 28 ].…”