Serum Homocysteine Level in Parkinson's Disease and Its Association with Duration, Cardinal Manifestation, and Severity of Disease

Fecal microbiota from patients with Parkinson's disease intensifies inflammation and neurodegeneration in A53T mice

AIMS

We evaluated the potential of Parkinson's disease (PD) fecal microbiota transplantation to initiate or exacerbate PD pathologies and investigated the underlying mechanisms.

METHODS

We transplanted the fecal microbiota from PD patients into mice by oral gavage and assessed the motor and intestinal functions, as well as the inflammatory and pathological changes in the colon and brain. Furthermore, 16S rRNA gene sequencing combined with metabolomics analysis was conducted to assess the impacts of fecal delivery on the fecal microbiota and metabolism in recipient mice.

RESULTS

The fecal microbiota from PD patients increased intestinal inflammation, deteriorated intestinal barrier function, intensified microglia and astrocyte activation, abnormal deposition of α-Synuclein, and dopaminergic neuronal loss in the brains of A53T mice. A mechanistic study revealed that the fecal microbiota of PD patients stimulated the TLR4/NF-κB/NLRP3 pathway in both the brain and colon. Additionally, multiomics analysis found that transplantation of fecal microbiota from PD patients not only altered the composition of the gut microbiota but also influenced the fecal metabolic profile of the recipient mice.

CONCLUSION

The fecal microbiota from PD patients intensifies inflammation and neurodegeneration in A53T mice. Our findings demonstrate that imbalance and dysfunction in the gut microbiome play significant roles in the development and advancement of PD.

Homocysteine and Parkinson's disease

Homocysteine (Hcy) is an important metabolite in methionine metabolism. When the metabolic pathway of homocysteine is abnormal, it will accumulate in the body and eventually lead to hyperhomocysteinemia. In recent years, many studies have found that hyperhomocysteinemia is related to the occurrence and development of Parkinson's disease. This study reviews the roles of homocysteine in the pathogenesis of Parkinson's disease and illustrates the harmful effects of hyperhomocysteinemia on Parkinson's disease.

Exploring the complexities of 1C metabolism: implications in aging and neurodegenerative diseases

The intricate interplay of one-carbon metabolism (OCM) with various cellular processes has garnered substantial attention due to its fundamental implications in several biological processes. OCM serves as a pivotal hub for methyl group donation in vital biochemical reactions, influencing DNA methylation, protein synthesis, and redox balance. In the context of aging, OCM dysregulation can contribute to epigenetic modifications and aberrant redox states, accentuating cellular senescence and age-associated pathologies. Furthermore, OCM's intricate involvement in cancer progression is evident through its capacity to provide essential one-carbon units crucial for nucleotide synthesis and DNA methylation, thereby fueling uncontrolled cell proliferation and tumor development. In neurodegenerative disorders like Alzheimer's and Parkinson's, perturbations in OCM pathways are implicated in the dysregulation of neurotransmitter synthesis and mitochondrial dysfunction, contributing to disease pathophysiology. This review underscores the profound impact of OCM in diverse disease contexts, reinforcing the need for a comprehensive understanding of its molecular complexities to pave the way for targeted therapeutic interventions across inflammation, aging and neurodegenerative disorders.

Association between the risk and severity of Parkinson's disease and plasma homocysteine, vitamin B12 and folate levels: a systematic review and meta-analysis

Background

Parkinson's disease (PD) is recognized as the second most prevalent progressive neurodegenerative disease among the elderly. However, the relationship between PD and plasma homocysteine (Hcy), vitamin B12, and folate has yielded inconsistent results in previous studies. Hence, in order to address this ambiguity, we conducted a meta-analysis to summarize the existing evidence.

Methods

Suitable studies published prior to May 2023 were identified by searching PubMed, EMBASE, Medline, Ovid, and Web of Science. The methodological quality of eligible studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). Meta-analysis and publication bias were then performed using R version 4.3.1.

Results

The results of our meta-analysis, consisting of case-control and cross-sectional studies, showed that PD patients had lower folate and vitamin B12 levels (SMD [95%CI]: -0.30[-0.39, -0.22], p < 0.001 for Vitamin B12; SMD [95%CI]: -0.20 [-0.28, -0.13], p < 0.001 for folate), but a significant higher Hcy level (SMD [95%CI]: 0.86 [0.59, 1.14], p < 0.001) than healthy people. Meanwhile, PD was significantly related to hyperhomocysteinemia (SMD [95%]: 2.02 [1.26, 2.78], p < 0.001) rather than plasma Hcy below 15 μmol/L (SMD [95%]: -0.31 [-0.62, 0.00], p = 0.05). Subgroup analysis revealed associations between the Hcy level of PD patients and region (p = 0.03), age (p = 0.03), levodopa therapy (p = 0.03), Hoehn and Yahr stage (p < 0.001), and cognitive impairment (p < 0.001). However, gender (p = 0.38) and sample size (p = 0.49) were not associated.

Conclusion

Hcy, vitamin B12, and folic acid potentially predict the onset and development of PD. Additionally, multiple factors were linked to Hcy levels in PD patients. Further studies are needed to comprehend their roles in PD.

The Role of Vitamins in Neurodegenerative Disease: An Update

Acquiring the recommended daily allowance of vitamins is crucial for maintaining homeostatic balance in humans and other animals. A deficiency in or dysregulation of vitamins adversely affects the neuronal metabolism, which may lead to neurodegenerative diseases. In this article, we discuss how novel vitamin-based approaches aid in attenuating abnormal neuronal functioning in neurodegeneration-based brain diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease, Amyotrophic lateral sclerosis, and Prion disease. Vitamins show their therapeutic activity in Parkinson's disease by antioxidative and anti-inflammatory activity. In addition, different water- and lipid-soluble vitamins have also prevented amyloid beta and tau pathology. On the other hand, some results also show no correlation between vitamin action and the prevention of neurodegenerative diseases. Some vitamins also exhibit toxic activity too. This review discusses both the beneficial and null effects of vitamin supplementation for neurological disorders. The detailed mechanism of action of both water- and lipid-soluble vitamins is addressed in the manuscript. Hormesis is also an essential factor that is very helpful to determine the effective dose of vitamins. PubMed, Google Scholar, Web of Science, and Scopus were employed to conduct the literature search of original articles, review articles, and meta-analyses.

Gut Microbiome and Serum Metabolome Alterations Associated with Isolated Dystonia

Dystonia is a complex neurological movement disorder characterized by involuntary muscle contractions. Increasing studies implicate the microbiome as a possible key susceptibility factor for neurological disorders, but the relationship between the gut microbiota and dystonia remains poorly explored. Here, the gut microbiota of 57 patients with isolated dystonia and 27 age- and environment-matched healthy controls was analyzed by 16S rRNA gene amplicon sequencing. Further, integrative analysis of the gut microbiome and serum metabolome measured by high-performance liquid chromatography-mass spectrometry was performed. No difference in α-diversity was found, while β-diversity was significantly different, with a more heterogeneous community structure among dystonia patients than among controls. The most significant changes in dystonia highlighted an increase in Clostridiales, including Blautia obeum, Dorea longicatena, and Eubacterium hallii, and a reduction in Bacteroides vulgatus and Bacteroides plebeius. The functional analysis revealed that genes related to tryptophan and purine biosynthesis were more abundant in gut microbiota from patients with dystonia, while genes linked to citrate cycle, vitamin B₆, and glycan metabolism were less abundant. The evaluation of serum metabolites revealed altered levels of l-glutamic acid, taurine, and d-tyrosine, suggesting changes in neurotransmitter metabolism. The most modified metabolites strongly inversely correlated with the abundance of members belonging to the Clostridiales, revealing the effect of the gut microbiota on neurometabolic activity. This study is the first to reveal gut microbial dysbiosis in patients with isolated dystonia and identified potential links between gut microbiota and serum neurotransmitters, providing new insight into the pathogenesis of isolated dystonia.

IMPORTANCE Dystonia is the third most common movement disorder after essential tremor and Parkinson’s disease. However, the cause for the majority of cases is not known. This is the first study so far that reveals significant alterations of gut microbiome and correlates the alteration of serum metabolites with gut dysbiosis in patients with isolated dystonia. We demonstrated a general overrepresentation of Clostridiales and underrepresentation of Bacteroidetes in patients with dystonia in comparison with healthy controls. The functional analysis found that genes related to the biosynthesis of tryptophan, which is the precursor of the neurotransmitter serotonin, were more active in isolated dystonia patients. Altered levels of several serum metabolites were found to be associated with microbial changes, such as d-tyrosine, taurine, and glutamate, indicating differences in neurotransmitter metabolism in isolated dystonia. Integrative analysis suggests that neurotransmitter system dysfunction may be a possible pathway by which the gut microbiome participates in the development of dystonia. The gut microbiome changes provide new insight into the pathogenesis of dystonia, suggesting new potential therapeutic directions.

Comparison of Serum Lead and Cadmium Levels in Parkinson's Patients and Healthy Controls

Background: Several studies have investigated the association of heavy metals such as lead and cadmium with neurodegenerative diseases such as Parkinson's disease. Objectives: In this study, we investigated the relationship between the serum levels of lead and cadmium in Parkinson's disease. Methods: In this case-control study, the serum levels of lead and cadmium in 100 patients with Parkinson's disease referred to our university hospital, and 30 healthy individuals were investigated. Basic information such as age and gender and other demographic and clinical data were registered in the checklist. The levels of lead and cadmium were measured using atomic absorption spectrophotometry (AAS). Data was analyzed by SPSS software version 23, and a P < 0.05 was considered as significant. Results: The mean cadmium level in patient and control groups was 14.91 ± 8.72 and 4.71 ± 2.72 ppb, respectively (P < 0.001). The mean lead level was 158.35 ± 157.64 and 35.35 ± 16.25 ppb in patients and controls, respectively (P < 0.001). At ages above 65 years, there was a significant difference between the level of cadmium (P < 0.001) and lead (P < 0.001) in patients and healthy subjects. In addition, there was a significant difference in the level of cadmium (P = 0.003) between patients and healthy subjects at ages below 65 years. This was true for both males (P < 0.05) and females (P < 0.05). There was no significant difference in the level of lead and cadmium in various severity rates of the disease, as well as in different symptoms of the patients. Conclusions: Based on the findings, the levels of serum lead and cadmium were higher in the patients, indicating a probable relationship between the Parkinson's disease and the levels of these metals.

Homocysteine fibrillar assemblies display cross-talk with Alzheimer's disease β-amyloid polypeptide

High levels of homocysteine are reported as a risk factor for Alzheimer's disease (AD). Correspondingly, inborn hyperhomocysteinemia is associated with an increased predisposition to the development of dementia in later stages of life. Yet, the mechanistic link between homocysteine accumulation and the pathological neurodegenerative processes is still elusive. Furthermore, despite the clear association between protein aggregation and AD, attempts to develop therapy that specifically targets this process have not been successful. It is envisioned that the failure in the development of efficacious therapeutic intervention may lie in the metabolomic state of affected individuals. We recently demonstrated the ability of metabolites to self-assemble and cross-seed the aggregation of pathological proteins, suggesting a role for metabolite structures in the initiation of neurodegenerative diseases. Here, we provide a report of homocysteine crystal structure and self-assembly into amyloid-like toxic fibrils, their inhibition by polyphenols, and their ability to seed the aggregation of the AD-associated β-amyloid polypeptide. A yeast model of hyperhomocysteinemia indicates a toxic effect, correlated with increased intracellular amyloid staining that could be rescued by polyphenol treatment. Analysis of AD mouse model brain sections indicates the presence of homocysteine assemblies and the interplay between β-amyloid and homocysteine. This work implies a molecular basis for the association between homocysteine accumulation and AD pathology, potentially leading to a paradigm shift in the understanding of AD initial pathological processes.

Psychiatric Symptoms in Patients and Caregivers with Parkinson's Disease

Objectives

Psychiatric disorders in patients with Parkinson’s disease (PD) and their caregivers play an important role in patients’ treatment and follow-up. Our study aimed to examine the prevalence of psychiatric symptoms among patients with PD and their caregivers, demographic risk factors, and the influence of severity and manifestations of PD on psychiatric distress.

Methods

We included 125 patients with PD and 125 of their primary caregivers in this descriptive cross-sectional study. The severity of PD was evaluated according to the Hoehn and Yahr severity scale from the Movement Disorder Society-Sponsored Revision of the Unified Parkinson’s Disease Rating Scale. PD patients and their caregivers completed the Symptom Checklist-25 to determine the presence of psychiatric distress. Also, demographic factors, including age, high level of education, occupation, residence, and cigarette smoking, were assessed in the PD patients and their caregivers.

Results

The prevalence of psychiatric distress was 47.2% for PD patients and 18.4% for caregivers. Female sex, city residency, and medical disease were risk factors for more psychiatric symptoms in PD patients. Also, the female sex, single status, living in a village, and having a medical disease were risk factors for greater psychiatric symptoms in caregivers. PD patients in more advanced stages of disease suffered significantly from psychiatric distress, somatization, anxiety, interpersonal sensitivity, obsessive-compulsive disorder, and phobia compared to the lower severity of disease. PD patients with manifestation of postural instability showed a higher score of somatization, phobia, and psychiatric distress as compared with tremor, hypokinesia, and rigidity.

Conclusions

Progression of PD influenced the psychiatric symptoms of both patients and their caregivers. A higher stage of PD is associated with higher scores of psychiatric distress, phobia, and somatization in the patients and their caregivers.

Comparison of the calcium-related factors in Parkinson's disease patients with healthy individuals

Background:

Parkinson’s disease (PD) is one of the most common neurodegenerative diseases (ND). Studies have demonstrated that biochemical markers have an association with PD. We aimed to investigate an association of biochemical markers including calcium, vitamin D, alkaline phosphatase (ALP), parathormone (PTH), and phosphorous with PD.

Methods:

This study was conducted on 139 PD patients and 100 healthy individuals. Serum levels of calcium, phosphorous, ALP, PTH and vitamin D were evaluated. Furthermore, student’s t-test and logistic regression models were used by SPSS.

Results:

The mean levels of calcium (9.4±0.7 and 9.0±0.8 ) and vitamin D (29.7±22.1 and 25.8±23.7) were higher in PD patients as compared with healthy controls, which only status of calcium being significantly different in the two groups (P<0.001). Levels of ALP (202.4±96.7 and 242.9±142.4) and phosphorous (3.6±0.6 and 4.22±1.1) were significantly different comparing PD patients with healthy subjects (P<0.01, P<0.001, respectively). ALP and phosphorous were significantly different in the two groups (OR=0.996, [CI 95%, 0.994-0.999], P<0.001, OR=0.475, [CI 95%, 0.325-0.694], P<0.001, respectively). Furthermore, increased levels of calcium resulted in an elevated risk of PD (OR=2.175, [CI 95% 1.377-3.435], P<0.001).

Conclusion:

Results show that mean levels of calcium are higher in PD patients relative to healthy controls. Thereby, higher levels of calcium may be associated with PD.