Biological determinants of blood-based cytokines in the Alzheimer's Disease clinical continuum

Converging translational and clinical research strongly indicates that altered immune and inflammatory homeostasis (neuroinflammation) plays a critical pathophysiological role in Alzheimer's disease (AD), across the clinical continuum. A dualistic role of neuroinflammation may account for a complex biological phenomenon, representing a potential pharmacological target. Emerging blood-based pathophysiological biomarkers, such as cytokines (Cyt) and interleukins (ILs) have been studied as indicators of neuroinflammation in AD. However, inconsistent results have been reported, probably due to lack of standardization of assays with methodological and analytical differences. We used machine-learning and a cross-validation-based statical workflow to explore and analyze the potential impact of key biological factors, such as age, sex, apolipoproteinE (APOE) genotype (the major genetic risk factor for late-onset AD) on Cyt. A set of Cyt was selected based on previous literature, and we investigated any potential association in a pooled cohort of cognitively healthy, mild cognitive impairment (MCI), and AD-like dementia patients. We also performed explorative analyses to extrapolate preliminary clinical insights. We found a robust sex effect on IL12 and an APOE-related difference in IL10, with the latter being also related to the presence of advanced cognitive decline. IL1β was the variable most significantly associated with MCI-to-dementia conversion over a 2.5 year-clinical follow-up. Albeit preliminary, our data support further clinical research to understand whether plasma Cyt may represent reliable and non-invasive tools serving the investigation of neuroimmune and inflammatory dynamics in AD and to foster biomarker-guided pathway-based therapeutic approaches, within the precision medicine development framework.

Targeting mitochondrial dysfunction and neurodegeneration by means of coenzyme Q10 and its analogues

Coenzyme Q10 is a small electron carrier of the respiratory chain with antioxidant properties, widely used for the treatment of mitochondrial disorders. Mitochondrial diseases are neuromuscular disorders caused by impairment of the respiratory chain and increased generation of reactive oxygen species. Coenzyme Q10 supplementation is fundamental in patients with primary coenzyme Q10 deficiency. Furthermore, coenzyme Q10 and its analogues, idebenone and mitoquinone (or MitoQ), have been also used in the treatment of other neurogenetic/neurodegenerative disorders. In Friedreich ataxia idebenone may reduce cardiac hypertrophy and, at higher doses, also improve neurological function. These compounds may also play a potential role in other conditions which have been linked to mitochondrial dysfunction, such as Parkinson disease, Huntington disease, amyotrophic lateral sclerosis and Alzheimer disease. This review introduces mitochondrial disorders and Friedreich ataxia as two paradigms of the tight links existing between oxidative stress, respiratory chain dysfunction and neurodegeneration, and focuses on current and emerging therapeutic uses of coenzyme Q10 and idebenone in neurology.

Tetracycline treatment in patients with progressive external ophthalmoplegia

BACKGROUND

Tetracyclines could have neuroprotective effects in neuromuscular and neurodegenerative disorders. AIMS OF THE STUDY AND METHODS: Objective of this double-blind randomized pilot study (followed by an adjunctive open-label phase) was to evaluate whether tetracycline (500 mg/day × 14 days/month × 3 months) could be useful in patients (n = 16) with progressive external ophthalmoplegia (PEO).

RESULTS

Our results do not formally support any effect of tetracycline on eye motility in PEO. However, some possible protective effects could not be completely ruled out, i.e. a further analysis suggests a possible difference between the tetracycline group and the placebo group, significant at least for oblique motility, when comparing the ratio between the end of the double-blind phase and baseline. Tetracycline could modify some oxidative stress biomarkers in patients with PEO.

CONCLUSIONS

Further studies are needed to confirm such effects of tetracycline in patients with PEO, if any, and to clarify the mechanisms of action for antioxidant effects of tetracyclines in mitochondrial disorders and other diseases.