Sex, myelin, and clinical characteristics of Parkinson’s disease

Abstract

ObjectiveTo determine if there are sex differences in myelin in Parkinson’s disease, and whether these explain some of the previously-described sex differences in clinical presentation.MethodsThirty-three subjects (23 males, 10 females) with Parkinson’s disease underwent myelin water fraction (MWF) imaging, an MRI scanning technique of in vivo myelin content. MWF of 20 white matter regions of interest (ROIs) were assessed. Motor symptoms were assessed using the Unified Parkinson’s Disease Rating Scale (UPDRS). Principal component analysis, logistic and multiple linear regressions, and t-tests were used to determine which white matter ROIs differed between sexes, the clinical features associated with these myelin changes, and if overall MWF and MWF laterality differed between males and females.ResultsConsistent with prior reports, tremor and bradykinesia were more likely seen in females, whereas rigidity and axial symptoms were more likely seen in males in our cohort. MWF of the thalamic radiation, cingulum, cingulum hippocampus, inferior fronto-occipital fasciculi, inferior longitudinal fasciculi, and uncinate were significant in predicting sex. Overall MWF and asymmetry of MWF was greater in males. MWF differences between sexes were associated with tremor symptomatology and asymmetry of motor performance.ConclusionSex differences in myelin are associated with tremor and asymmetry of motor presentation. While preliminary, our results suggest that further investigation of the role of biological sex in myelin pathology and clinical presentation in Parkinson’s disease is warranted.

The role of autophagy in Parkinson’s disease: a gender difference overview

“…Gray matter, made up of neurons that acts trough synapses, is involved in cognitive, sensory and motor functions, while white matter is composed of myelinated nerve fibers that play a key role in neuronal communication. Neuroanatomical differences between men and women, highlighted by Cai et al (2023) , further contribute to the complexity of the picture. Females have a greater relative Gray matter volume, while males have a greater relative white matter volume.…”

“…Females have a greater relative Gray matter volume, while males have a greater relative white matter volume. Brain structure, including the size of the basal nuclei, appears to vary differentially between the sexes, introducing additional variables that could modulate the manifestation of PD ( Cai et al, 2023 ). Analysing the ratio of Gray and white matter through neuroimaging techniques can provide valuable insights into the location and extent of brain degeneration at different stages of the disease.…”