[Research progress on striatal D2-MSNs plasticity mediated improvement of motor dysfunction by exercises in Parkinson's disease].

Parkinson's disease (PD), a prevalent neurodegenerative condition, manifests predominantly through the degeneration of nigrostriatal dopaminergic (DA) pathways, culminating in a notable depletion of striatal dopamine. This pathophysiological process critically impairs the DA-mediated regulation of motor behaviors within the basal ganglia circuitry, particularly impacting various subtypes of striatal medium spiny neurons. Recent advancements in neuroscientific research have illuminated the pivotal role of D2-dopamine receptor expressing medium spiny neurons (D2-MSNs) plasticity in coordinating motor control in PD. Intriguingly, aerobic exercise emerges as a potent therapeutic intervention, capable of preventing or improving motor impairments. This ameliorative effect is mediated through the modulation of DA receptor activity and the consequent activation of downstream extracellular signal-regulated kinase (Erk) signaling pathway. This article meticulously reviewed the intricate regulatory mechanisms governing the structural and functional plasticity of striatal D2-MSNs in the context of PD. It particularly emphasized the transformative impact of aerobic exercise on motor deficits in PD, attributing this effect to the modulation of striatal D2-MSNs.

Age-related changes of lens thickness and density in different age phases.

AIM: To explore the changes in lens thickness and density with age. METHODS: A Chinese population-based retrospective study was performed. A total of 497 individuals (490 right eyes and 495 left eyes), ranging from 3 to 69 years old were included. Lens images obtained from IOL Master 700 were used to measure lens thickness and density. Piecewise regression model was chosen to illustrate the relationship of lens thickness and density with age. RESULTS: The proportion of people aged 3-18, 19-40, over 40 was 38.6%, 50.9% and 10.5% respectively. The whole lens thickness decreased with age during the first 7 years of life, kept stable from 8 to 16 years old, and then increased at the rate of about 27 µm per year. The thickness of the lens cortex and nucleus tended to decrease first and then increase with age, which was dependent on age stages. The whole lens density also decreased with age until 7 years old. The increasing rate of lens density was different in different age groups. The whole lens density increased rapidly from 7 to 22 years old and slowed down after 22 years old. Similarly, the changing tendency of lens cortical and nuclear density differed in different age phases. CONCLUSION: Both lens thickness and density are significantly associated with age, whereas they do not change linearly with age. Moreover, it is necessary to increase the population over 40 years old and conduct further research.

Refractive Error and Eye Health: An Umbrella Review of Meta-Analyses.

Purpose: To explore the associations between refractive errors and multiple eye health outcomes. Methods: This is an umbrella review based on systematic reviews with meta-analyses. In our study, refractive errors included myopia, hyperopia, astigmatism, and anisometropia. We reconducted the meta-analyses whose primary data were available in sufficient detail by random effect model. Heterogeneity was assessed by I 2. The main outcomes included myopic macular degeneration (MMD), retinal detachment (RD), cataract, open-angle glaucoma (OAG), strabismus, age-related macular degeneration (AMD), and diabetic retinopathy (DR). Results: Myopia was associated with increased risk of MMD (relative risk = 102.11, 95% CI 52.6-198.22), RD (3.45, 1.08-11.00), nuclear cataract (2.15, 1.53-3.03), posterior subcapsular (PSC) cataract (1.74, 1.41-2.15), OAG (1.95, 1.74-2.19), exotropia (5.23, 2.26-12.09), but decreased risk of DR (0.83, 0.66-1.04), and early AMD (0.80, 0.67-0.94). From mild-to-high myopia, the association strengthened for MMD, RD, nuclear cataract, PSC cataract, OAG, and DR. Hyperopia was associated with an increased risk of early AMD (1.09, 1.01-1.18) and esotropia (22.94, 10.20-51.62). Astigmatism and anisometropia were associated with increased risk of both exotropia and esotropia. Conclusions: Myopia, especially high myopia, demonstrated the highest risk for eye health outcomes, such as MMD, RD, OAG, nuclear and PSC cataracts, and exotropia. However, myopia was associated with a lower risk of early AMD and DR. Individuals with hyperopia are more likely to suffer early AMD and esotropia. Astigmatism and anisometropia predispose to strabismus. A lot of research studies on the mechanism of the associations are needed. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=239744; identifier: 239744.