Qingfeng Zhai

Parkinson’s disease (PD) is a complex neurodegenerative disorder characterized by a pathology that includes the aggregation of alpha-synuclein (α-syn), oxidative stress, and neuroinflammation. While existing treatments can alleviate motor symptoms, they have limited efficacy in slowing disease progression and improving non-motor symptoms. In recent years, molecular hydrogen has been recognized for its potential neuroprotective effects, attributed to its selective antioxidant and anti-inflammatory properties. While preclinical studies demonstrate promising results, clinical trials conducted thus far have yielded mixed outcomes, with some trials reporting limited or no therapeutic benefit. This review systematically analyzes the mechanisms of action of molecular hydrogen in PD and related neurodegenerative disorders, emphasizing its antioxidant, anti-inflammatory, and anti-apoptotic properties. By evaluating evidence from both preclinical and clinical studies, this paper explores the potential of molecular hydrogen to attenuate oxidative stress, modulate inflammatory responses, and inhibit apoptosis in neuronal cells, while also identifying key gaps in current research. As a novel neuroprotective agent, molecular hydrogen holds potential in PD and other neurodegenerative diseases, but further well-designed clinical trials are needed to validate its efficacy. Future studies should focus on elucidating the mechanisms through which hydrogen exerts its neuroprotective effects, particularly concerning α-syn aggregation and its clearance pathways, as well as Nrf2-mediated immunomodulation. Furthermore, large-scale, multicenter clinical trials are necessary to establish efficacy benchmarks and personalized delivery protocols.

This study systematically analyzes the relationship of vitamin A on the neonatal respiratory diseases. An extensive literature search for relevant studies was conducted on PubMed, Web of Science, and so on. After screening in strict accordance with the inclusion and exclusion criteria, 12 articles on vitamin A deficiency and 12 articles on vitamin A supplementation were included. Stata 17.0 software was used to perform meta‐analysis, heterogeneity test, and sensitivity analysis, and the corresponding mathematical model was used to merge the data. The meta‐analysis results of the relationship between vitamin A deficiency and neonatal respiratory diseases indicated that compared with the neonates with normal vitamin A, the neonates with vitamin A deficiency had adverse health outcomes of neonatal respiratory diseases (OR = 4.86, 95% CI: 2.68–8.84), of which neonatal respiratory distress syndrome (NRDS) (OR = 4.10, 95% CI: 2.32–7.23) and neonatal pneumonia (OR = 3.22, 95% CI: 2.18–4.77) were analyzed by subgroup analysis. The meta‐analysis of the relationship between vitamin A supplementation therapy and neonatal respiratory diseases showed that vitamin A supplementation was an effective therapeutic measure for neonatal respiratory diseases (RR = 1.06, 95% CI: 1.04–1.07): NRDS (RR = 1.03, 95% CI: 1.02–1.05) and NBPD (RR = 1.08, 95% CI: 1.01–1.15). The funnel chart method results show that there was publication bias in studies on vitamin A deficiency induced to and vitamin A supplementation therapy for neonatal respiratory diseases. The sensitivity analysis results showed that excluding some special article had some effect on the final pooled effect. But generally speaking, the result of meta‐analysis was stable. There is a statistical correlation of vitamin A on the neonatal respiratory diseases from two aspects of etiological exploration and effect evaluation of treatment.