Aims and objectives
Neuromelanin (NM) is a dark pigmented granule preferentially found in catecholaminergic neurons,
such as the substantia nigra (SN) and locus coeruleus (LC).
NM acts as a scavenger that removes excess of potentially toxic substances.
Given this capacity,
NM may be neuroprotective [2] but when released from degenerating neurons may also induce immune-based pathogenic mechanisms and trigger neurodegeneration [3,4].
Parkinson’s disease (PD) has been hypothesised to result from accelerated aging due to exacerbation of oxidative stress in the SN in addition to environmental toxins in which...
Methods and materials
Participants:
This retrospective study pooled data of healthy participants across several prospectively recruiting.
All participants aged 16 years and over gave informed consent,
and consent was provided by the parent or guardian for participants aged under 16 years.
97 healthy control volunteers who were free from major neurologic,
psychiatric or medical disorders were included.
Imaging acquisition:
All participants underwent MRI using a 3T GE scanner (Discovery MR750,
GE Healthcare,
Milwaukee,
WI) with 32-channel head coil.
The head was stabilized with inflated foam padding.
The 3D...
Results
The final analysis included 94 healthy participants aged from 5.1 to 82.02 years old (mean age ± SD,
31.55±21.66; 40 males and 54 females).
Age effect on the pigmented SN volume
Volume increases from early life time up to about 53 years of age and then gradually decreases,
presenting a reversed U shape (Figure 2).
We found a significant age effect on the suprathreshold volume with dataand the adjusted R2 of 0.421.
The volume of the midbrain at the level of the SN (P=0.843) and...
Conclusion
We describe a strong non-linear age effect on brainstem pigmentation with an inverted U-shaped association providing the first detailed trajectory of MR detectable brainstem pigmentation and depigmentation from childhood to old age.
Our fast protocol makes possible to investigate the risk and moderator factors of physiological and pathological brainstem depigmentation,
shedding light on the putative neuro-protective and -toxic effects of NM and iron.
References
1.
Sulzer,
D.
and L.
Zecca,
Intraneuronal dopamine-quinone synthesis: a review. Neurotox Res,
2000.
1(3): p.
181-95.
2.
Zecca,
L.,
et al.,
Neuromelanin can protect against iron-mediated oxidative damage in system modeling iron overload of brain aging and Parkinson's disease. J Neurochem,
2008.
106(4): p.
1866-75.
3.
Ito,
S.,
Encapsulation of a reactive core in neuromelanin. Proceedings of the National Academy of Sciences of the United States of America,
2006.
103(40): p.
14647-14648.
4.
Zucca,
F.A.,
et al.,
Neuromelanin of the human substantia nigra: an...