How much does sex matter in Parkinson disease?

Gender differences in non-motor fluctuations in Parkinson's disease

Non-motor symptoms (NMS) and Non-motor fluctuations (NMF) in Parkinson's Disease (PD) are common, involving several domains and affecting quality of life. Aim of the study is to estimate the burden of NMF in PD patients and to evaluate the possible gender effect. PD patients fulfilling the MDS-PD diagnostic criteria attending the "Parkinson's Disease and Movement Disorders Centre" of the University of Catania were evaluated using the Non-Motor Fluctuations Assessment (NoMoFA) Questionnaire. NoMoFA items were also grouped into the following domains: cognitive, mood, sleep/fatigue, dysautonomia, hallucination/perception and miscellaneous domains were identified. One-hundred and twenty-one patients with PD (67 men, 55.4%; mean age 70.2 ± 8.9 years, disease duration 8.3 ± 4.6 years) were evaluated. All PD patients reported at least one NMS, whereas 87 (71.9%) also reported NMF. "Feel sluggish or had low energy levels" (47.2%) along with "Feel excessively sleepy during the day" (40.0%) were the most common NMF reported in the whole sample. The majority of PD patients reported the presence of NMF during the OFF state (79, 65.3%). At multivariate analysis, NMF were positively associated with the female gender (adjusted OR 3.13; 95%CI 1.21-8.11 p-value 0.01). Women with PD had higher NMF scores especially in depression/anxiety, sleep/fatigue and dysautonomia domains. Our study reported the presence of a gender-related pattern in the frequency of NMS and NMF in PD patients, with female gender associated with a higher risk of developing NMF, highlighting the need for personalized treatment strategies when addressing NMF.

α-synucleinopathy exerts sex-dimorphic effects on the multipurpose DNA repair/redox protein APE1 in mice and humans

Lewy body disorders are characterized by oxidative damage to DNA and inclusions rich in aggregated forms of α-synuclein. Among other roles, apurinic/apyrimidinic endonuclease 1 (APE1) repairs oxidative DNA damage, and APE1 polymorphisms have been linked to cases of Lewy body disorders. However, the link between APE1 and α-synuclein is unexplored. We report that knockdown or inhibition of APE1 amplified inclusion formation in primary hippocampal cultures challenged with preformed α-synuclein fibrils. Fibril infusions into the mouse olfactory bulb/anterior olfactory nucleus (OB/AON) elicited a modest decrease in APE1 expression in the brains of male mice but an increase in females. Similarly, men with Lewy body disorders displayed lower APE1 expression in the OB and amygdala compared to women. Preformed fibril infusions of the mouse OB/AON induced more robust base excision repair of DNA lesions in females than males. No fibril-mediated loss of APE1 expression was observed in male mice when the antioxidant N-acetylcysteine was added to their diet. These findings reveal a potential sex-biased link between α-synucleinopathy and APE1 in mice and humans. Further studies are warranted to determine how this multifunctional protein modifies α-synuclein inclusions and, conversely, how α-synucleinopathy and biological sex interact to modify APE1.

Heat Shock Protein 70 as a Sex-Skewed Regulator of α-Synucleinopathy

The role of molecular chaperones, such as heat shock protein 70 (Hsp70), is not typically studied as a function of biological sex, but by addressing this gap we might improve our understanding of proteinopathic disorders that predominate in one sex. Therefore, we exposed male or female primary hippocampal cultures to preformed α-synuclein fibrils in a model of early-stage Lewy pathology. We first discovered that two mechanistically distinct inhibitors of Hsp70 function increased phospho-α-synuclein+ inclusions more robustly in male-derived neurons. Because Hsp70 is released into extracellular compartments and may restrict cell-to-cell transmission/amplification of α-synucleinopathy, we then tested the effects of low-endotoxin, exogenous Hsp70 (eHsp70) in primary hippocampal cultures. eHsp70 was taken up by and reduced α-synuclein+ inclusions in cells of both sexes, but pharmacological suppression of Hsp70 function attenuated the inhibitory effect of eHsp70 on perinuclear inclusions only in male neurons. In 20-month-old male mice infused with α-synuclein fibrils in the olfactory bulb, daily intranasal eHsp70 delivery also reduced inclusion numbers and the time to locate buried food. eHsp70 penetrated the limbic system and spinal cord of male mice within 3 h but was cleared within 72 h. Unexpectedly, no evidence of eHsp70 uptake from nose into brain was observed in females. A trend towards higher expression of inducible Hsp70-but not constitutive Hsp70 or Hsp40-was observed in amygdala tissues from male subjects with Lewy body disorders compared to unaffected male controls, supporting the importance of this chaperone in human disease. Women expressed higher amygdalar Hsp70 levels compared to men, regardless of disease status. Together, these data provide a new link between biological sex and a key chaperone that orchestrates proteostasis.

Diabetes, insulin and new therapeutic strategies for Parkinson's disease: Focus on glucagon-like peptide-1 receptor agonists

Parkinson's disease and diabetes mellitus are two chronic disorders associated with aging that are becoming increasingly prevalent worldwide. Parkinson is a multifactorial progressive condition with no available disease modifying treatments at the moment. Over the last few years there is growing interest in the relationship between diabetes (and impaired insulin signaling) and neurodegenerative diseases, as well as the possible benefit of antidiabetic treatments as neuroprotectors, even in non-diabetic patients. Insulin regulates essential functions in the brain such as neuronal survival, autophagy of toxic proteins, synaptic plasticity, neurogenesis, oxidative stress and neuroinflammation. We review the existing epidemiological, experimental and clinical evidence that supports the interplay between insulin and neurodegeneration in Parkinson's disease, as well as the role of antidiabetic treatments in this disease.

Diabetes mellitus and Parkinson disease

OBJECTIVE

To investigate whether diabetes mellitus is associated with Parkinson-like pathology in people without Parkinson disease and to evaluate the effect of diabetes mellitus on markers of Parkinson pathology and clinical progression in drug-naive patients with early-stage Parkinson disease.

METHODS

We compared 25 patients with Parkinson disease and diabetes mellitus to 25 without diabetes mellitus, and 14 patients with diabetes mellitus and no Parkinson disease to 14 healthy controls (people with no diabetes mellitus or Parkinson disease). The clinical diagnosis of diabetes mellitus was confirmed by 2 consecutive fasting measurements of serum glucose levels >126 mL/dL. Over a 36-month follow-up period, we then investigated in the population with Parkinson disease whether the presence of diabetes mellitus was associated with faster motor progression or cognitive decline.

RESULTS

The presence of diabetes mellitus was associated with higher motor scores (p < 0.01), lower striatal dopamine transporter binding (p < 0.05), and higher tau CSF levels (p < 0.05) in patients with Parkinson disease. In patients with diabetes but without Parkinson disease, the presence of diabetes mellitus was associated with lower striatal dopamine transporter binding (p < 0.05) and higher tau (p < 0.05) and α-synuclein (p < 0.05) CSF levels compared to healthy controls. At the Cox survival analysis in the population of patients with Parkinson disease, the presence of diabetes mellitus was associated with faster motor progression (hazard ratio = 4.521, 95% confidence interval = 1.468-13.926; p < 0.01) and cognitive decline (hazard ratio = 9.314, 95% confidence interval = 1.164-74.519; p < 0.05).

CONCLUSIONS

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

Gender and non motor fluctuations in Parkinson's disease: A prospective study

INTRODUCTION

In Parkinson's disease (PD), non motor symptoms can fluctuate either along or irrespective to motor on/off phenomena. Prospective studies suggest that higher motor scores and levodopa dosage, younger age at onset and female gender represent risk factors for motor fluctuations' development. Yet, the predictors of development of non motor fluctuations (NMF) are less clear. In this prospective study, we aimed to assess the relationship between NMF and gender along with other potential risk factors.

METHODS

Forty-seven (16 women/31 men) de novo, drug-naïve PD patients have been followed for 4 years since diagnosis. Motor and non motor fluctuations were evaluated with the 19-item Wearing off Questionnaire (WOQ-19). The association between gender and NMF was explored with multivariable regression models adjusted for age at onset, motor and non motor symptoms at diagnosis and levodopa intake at follow up.

RESULTS

Female gender was more likely associated with a diagnosis of NMF (adjusted odds ratio, AOR = 5.33,95%CI = 1.21-23.4, p = 0.027), but not with a diagnosis of generic wearing off at follow up (OR = 3.66, 95%CI = 0.8-16.8, p = 0.097). Women had greater likelihood of developing higher WOQ-19 Non motor scores (AOR = 4.58, 95%CI = 1.23-17.03, p = 0.023), but not higher WOQ-19 Total scores (AOR = 2.88, 95%CI = 0.86-9.71, p = 0.087) compared to men. Notwithstanding, no gender differences were detected in medication intake.

CONCLUSIONS

We showed that female gender represents a major risk factor for the development of NMF. There were no gender differences in medication intake, thus NMF in women remain mostly underestimated and not properly treated. From a practical standpoint, clinicians should take into account the role of gender in the management of NMF in PD.