Biomimetic carbon nanotubes for neurological disease therapeutics as inherent medication

Nowadays, nanotechnology is revolutionizing the approaches to different fields from manufacture to health. Carbon nanotubes (CNTs) as promising candidates in nanomedicine have great potentials in developing novel entities for central nervous system pathologies, due to their excellent physicochemical properties and ability to interface with neurons and neuronal circuits. However, most of the studies mainly focused on the drug delivery and bioimaging applications of CNTs, while neglect their application prospects as therapeutic drugs themselves. At present, the relevant reviews are not available yet. Herein we summarized the latest advances on the biomedical and therapeutic applications of CNTs in vitro and in vivo for neurological diseases treatments as inherent therapeutic drugs. The biological mechanisms of CNTs-mediated bio-medical effects and potential toxicity of CNTs were also intensely discussed. It is expected that CNTs will exploit further neurological applications on disease therapy in the near future.

Chronic exposure to dopamine agonists affects the integrity of striatal D2 receptors in Parkinson's patients

We aimed to investigate the integrity and clinical relevance of striatal dopamine receptor type-2 (D₂R) availability in Parkinson's disease (PD) patients. We studied 68 PD patients, spanning from early to advanced disease stages, and 12 healthy controls. All participants received one [¹¹C]raclopride PET scan in an OFF medication condition for quantification of striatal D₂R availability in vivo. Parametric images of [¹¹C]raclopride non-displaceable binding potential were generated from the dynamic [¹¹C]raclopride scans using implementation of the simplified reference tissue model with cerebellum as the reference tissue. PET data were interrogated for correlations with clinical data related to disease burden and dopaminergic treatment. PD patients showed a mean 16.7% decrease in caudate D₂R and a mean 3.5% increase in putaminal D₂R availability compared to healthy controls. Lower caudate [¹¹C]raclopride BP_ND correlated with longer PD duration. PD patients on dopamine agonist treatment had 9.2% reduced D₂R availability in the caudate and 12.8% in the putamen compared to PD patients who never received treatment with dopamine agonists. Higher amounts of lifetime dopamine agonist therapy correlated with reduced D₂Rs availability in both caudate and putamen. No associations between striatal D₂R availability and levodopa treatment and dyskinesias were found. In advancing PD the caudate and putamen D₂R availability are differentially affected. Chronic exposure to treatment with dopamine agonists, but no levodopa, suppresses striatal D₂R availability, which may have relevance to output signaling to frontal lobes and the occurrence of executive deficits, but not dyskinesias.

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D₂R in caudate and putamen are differentially affected in PD.

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Loss of D₂R in caudate correlates with longer disease duration.

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Dopamine agonists treatment, but not levodopa, suppresses caudate and putamen D₂Rs.

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No association between striatal D₂R availability, levodopa treatment and dyskinesia.