Objective: To explore clinical phenotype and characteristics of Parkinson disease (PD) at different ages at onset in recently diagnosed patients with untreated PD. Methods:We have analyzed baseline data from the Parkinson's Progression Markers Initiative database. Four hundred twenty-two patients with a diagnosis of PD confirmed by DaTSCAN imaging were divided into 4 groups according to age at onset (onset younger than 50 years, 50-59 years, 60-69 years, and 70 years or older) and investigated for differences in side, type and localization of symptoms, occurrence/severity of motor and nonmotor features, nigrostriatal function, and CSF biomarkers.Results: Older age at onset was associated with a more severe motor and nonmotor phenotype, a greater dopaminergic dysfunction on DaTSCAN, and reduction of CSF a-synuclein and total tau. The most common presentation was the combination of 2 or 3 motor symptoms (bradykinesia, resting tremor, and rigidity) with rigidity being more common in the young-onset group. In about 80% of the patients with localized onset, the arm was the most affected part of the body, with no difference across subgroups. Conclusions:Although the presentation of PD symptoms is similar across age subgroups, the severity of motor and nonmotor features, the impairment of striatal binding, and the levels of CSF biomarkers increase with age at onset. The variability of imaging and nonimaging biomarkers in patients with PD at different ages could hamper the results of future clinical trials.

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There are currently no reliable predictors of cognitive impairment in Parkinson’s disease. Using both cross-sectional and longitudinal comparisons, Schulz et al. report that grey matter volume loss and increased mean diffusivity in the nucleus basalis of Meynert is predictive of cognitive impairment in Parkinson’s disease.

Diabetes mellitus may predispose toward a Parkinson-like pathology, and when present in patients with Parkinson disease, can induce a more aggressive phenotype.

Post-mortem and neuroimaging studies suggest that the serotonergic system, which originates from the brainstem raphe nuclei, is disrupted in Parkinson's disease. This could contribute to the occurrence of non-motor symptoms and tremor, which are only partially explained by dopamine loss. However, the level of involvement of the serotonergic raphe nuclei in early Parkinson's disease is still debated. (123)I-FP-CIT single photon emission computed tomography is a marker of dopamine and serotonin transporter availability. While (123)I-FP-CIT binds primarily to dopamine transporters in the striatum, its binding in the brainstem raphe nuclei reflects serotonin transporter availability. We interrogated baseline single photon emission computed tomography scans of subjects recruited by the Parkinson's Progression Markers Initiative to determine: (i) the integrity of the brainstem raphe nuclei in early Parkinson's disease; and (ii) whether raphe serotonin transporter levels correlate with severity of tremor and symptoms of fatigue, depression, and sleep disturbance. Three hundred and forty-five patients with early drug-naïve Parkinson's disease, 185 healthy controls, and 56 subjects with possible Parkinson's disease without evidence of dopaminergic deficit were included. In the Parkinson's disease cohort, 37 patients had a tremulous, 106 patients had a pure akinetic-rigid, and 202 had a mixed phenotype. Patients with Parkinson's disease had significantly lower serotonin transporter availability in the brainstem raphe nuclei compared to controls (P < 0.01) and subjects without evidence of dopaminergic deficit (P < 0.05). However, only 13% of patients with Parkinson's disease individually had reduced signals. Raphe serotonin transporter availability over the entire Parkinson's disease cohort were associated with rest tremor amplitude (β = -0.106, P < 0.05), rest tremor constancy (β = -0.109, P < 0.05), and index of rest tremor severity (β = -0.104, P < 0.05). The tremulous Parkinson's disease subgroup had significantly lower raphe serotonin transporter availability but less severe striatal dopaminergic deficits compared to akinetic-rigid patients with no resting tremor (P < 0.05). In tremulous patients, raphe serotonin transporter availability was also associated with rest tremor constancy (β = -0.380, P < 0.05) and index of rest tremor severity (β = -0.322, P < 0.05). There was no association between raphe serotonin transporter availability and fatigue, depression, excessive daytime sleepiness, or rapid eye movement sleep behaviour disorder in early Parkinson's disease. We conclude that the raphe nuclei are affected in a subgroup of early drug-naïve Parkinson's disease patients and that reduced raphe serotonin transporter availability is associated with the severity of resting tremor but not non-motor symptoms.

Alzheimer's disease (AD) is a devastating and progressive neurodegenerative disease for which there is no cure. Mild cognitive impairment (MCI) is considered a prodromal stage of the disease. Molecular imaging with positron emission tomography (PET) allows for the in vivo visualisation and tracking of pathophysiological changes in AD and MCI. PET is a very promising methodology for differential diagnosis and novel targets of PET imaging might also serve as biomarkers for disease‐modifying therapeutic interventions. This review provides an overview of the current status and applications of in vivo molecular imaging of AD pathology, specifically amyloid, tau, and microglial activation. PET imaging studies were included and evaluated as potential biomarkers and for monitoring disease progression. Although the majority of radiotracers showed the ability to discriminate AD and MCI patients from healthy controls, they had various limitations that prevent the recommendation of a single technique or tracer as an optimal biomarker. Newer research examining amyloid, tau, and microglial PET imaging in combination suggest an alternative approach in studying the disease process.

The presence of RBD in PD is associated with faster motor progression in patients with greater synuclein and dopaminergic pathology, and with higher risk of cognitive decline in patients with greater synuclein and amyloid pathology. Our findings provide an important direction toward understanding phenotypes and their prognosis in PD.

Elderly healthy individuals have a reduced exercise tolerance and a decreased left ventricle inotropic reserve related to increased vascular afterload, arterial-ventricular load mismatching, physical deconditioning and impaired autonomic regulation (the so called “β-adrenergic desensitization”). Adrenergic responsiveness is altered with aging and the age-related changes are limited to the β-adrenergic receptor density reduction and to the β-adrenoceptor-G-protein(s)-adenylyl cyclase system abnormalities, while the type and level of abnormalities change with species and tissues. Epidemiological studies have shown an high incidence and prevalence of heart failure in the elderly and a great body of evidence correlate the changes of β-adrenergic system with heart failure pathogenesis. In particular it is well known that: (a) levels of cathecolamines are directly correlated with mortality and functional status in heart failure, (b) β1-adrenergic receptor subtype is down-regulated in heart failure, (c) heart failure-dependent cardiac adrenergic responsiveness reduction is related to changes in G proteins activity. In this review we focus on the cardiovascular β-adrenergic changes involvement in the aging process and on similarities and differences between aging heart and heart failure.