A Prospective Study of the Prevalence of Parkinsonism in Patients With Liver Cirrhosis

The Intricate Interplay: Microbial Metabolites and the Gut-Liver-Brain Axis in Parkinson's Disease

Parkinson's Disease (PD) is a neurodegenerative disorder marked by the depletion of dopaminergic neurons. Recent studies highlight the gut-liver-brain (GLB) axis and its role in PD pathogenesis. The GLB axis forms a dynamic network facilitating bidirectional communication between the gastrointestinal tract, liver, and central nervous system. Dysregulation within this axis, encompassing gut dysbiosis and microbial metabolites, is emerging as a critical factor influencing PD progression. Our understanding of PD was traditionally centered on neurodegenerative processes within the brain. However, examining PD through the lens of the GLB axis provides new insights. This review provides a comprehensive analysis of microbial metabolites, such as short-chain fatty acids (SCFAs), trimethylamine-N-oxide (TMAO), kynurenine, serotonin, bile acids, indoles, and dopamine, which are integral to PD pathogenesis by modulation of the GLB axis. Our extensive research included a comprehensive literature review and database searches utilizing resources such as gutMGene and gutMDisorder. These databases have been instrumental in identifying specific microbes and their metabolites, shedding light on the intricate relationship between the GLB axis and PD. This review consolidates existing knowledge and underscores the potential for targeted therapeutic interventions based on the GLB axis and its components, which offer new avenues for future PD research and treatment strategies. While the GLB axis is not a novel concept, this review is the first to focus specifically on its role in PD, highlighting the importance of integrating the liver and microbial metabolites as central players in the PD puzzle.

Secondary parkinsonism associated with focal brain lesions

Focal imaging abnormalities in patients with parkinsonism suggest secondary etiology and require a distinctive clinical approach to diagnosis and treatment. We review different entities presenting as secondary parkinsonism associated with structural brain lesions, with emphasis on the clinical course and neuroimaging findings. Secondary parkinsonism may be due to vascular causes, hydrocephalus, space-occupying lesions, metabolic causes (including acquired hepatocerebral degeneration, diabetic uremic encephalopathy, basal ganglia calcifications, osmotic demyelination syndrome), hypoxic-ischaemic brain injury, intoxications (including methanol, carbon monoxide, cyanide, carbon disulfide, manganese poisoning and illicit drugs), infections and immune causes. The onset can vary from acute to chronic. Both uni-and bilateral presentations are possible. Rigidity, bradykinesia and gait abnormalities are more common than rest tremor. Coexisting other movement disorders and additional associated neurological signs may point to the underlying diagnosis. Neuroimaging studies are an essential part in the diagnostic work-up of secondary parkinsonism and may point directly to the underlying etiology. We focus primarily on magnetic resonance imaging to illustrate how structural imaging combined with neurological assessment can lead to diagnosis. It is crucial that typical imaging abnormalities are recognized within the relevant clinical context. Many forms of secondary parkinsonism are reversible with elimination of the specific cause, while some may benefit from symptomatic treatment. This heterogeneous group of acquired disorders has also helped shape our knowledge of Parkinson's disease and basal ganglia pathophysiology, while more recent findings in the field garner support for the network perspective on brain function and neurological disorders.

Investigating the Relationship between Chronic Liver Cirrhosis and Parkinsonism: A Comparative Analysis and a Suggested Diagnostic Scheme

Aim: Neurological manifestations are common in patients with chronic liver diseases. This study aimed to depict the association between liver cirrhosis and Parkinson's disease (PD) and propose a clinically relevant diagnostic scheme. Methods: We examined patients' medical records with PD and chronic liver impairment secondary to cirrhosis or liver metastases for temporal correlations between liver insult and Parkinsonian signs. Results: Thirty-five individuals with PD and chronic liver impairment were included due to either cirrhosis or liver metastases. In all 22 patients with PD and liver metastases, the diagnosis of PD preceded the diagnosis of cancer. Conversely, patients with cirrhosis were often diagnosed with liver impairment before diagnosing PD. Age at diagnosis did not account for this difference. Conclusions: This study reinforces the potential clinical association between cirrhosis and PD. We also provide a diagnostic scheme that may guide therapeutic interventions and prognostic assessments.

Chronic Liver Disease in the Older Patient-Evaluation and Management

PURPOSE OF REVIEW

As our population ages, the number of elderly patients with advanced chronic liver disease (ACLD) will increase. In this review we explore risk factors for liver injury, noninvasive assessment of liver disease, complications of cirrhosis, and management of frailty and sarcopenia in the older patient with ACLD.

RECENT FINDINGS

Multiple guidelines regarding ACLD have been updated over the past few years. New cutoffs for FIB-4 and NAFLD (MASLD - Metabolic Dysfunction Associated Steatotic Liver Disease) fibrosis scores for elderly patients are being validated. Older patients with MASLD benefit from caloric restriction, exercise programs, and GLP-1 agonists. Patients with ACLD need to be screened for alcohol use disorder with modified scoring systems, and if positive, benefit from referral to chemical dependency programs. Carvedilol and diuretics may safely be used in the elderly for portal hypertension and ascites, respectively, with careful monitoring. Malnutrition, frailty, sarcopenia, and bone mineral disease are common in older patients with ACLD, and early intervention may improve outcomes. Early identification of ACLD in elderly patients allows us to manage risk factors for liver injury, screen for complications, and implement lifestyle and pharmacological therapy to reduce decompensation and death. Future studies may clarify the role of noninvasive imaging in assessing liver fibrosis in the elderly and optimal interventions for nutrition, frailty, sarcopenia, bone health in addition to reevaluation of antibiotic prophylaxis for liver conditions with rising antibiotic resistance.

Literature-Based Discovery Predicts Antihistamines Are a Promising Repurposed Adjuvant Therapy for Parkinson's Disease

Parkinson's disease (PD) is a movement disorder caused by a dopamine deficit in the brain. Current therapies primarily focus on dopamine modulators or replacements, such as levodopa. Although dopamine replacement can help alleviate PD symptoms, therapies targeting the underlying neurodegenerative process are limited. The study objective was to use artificial intelligence to rank the most promising repurposed drug candidates for PD. Natural language processing (NLP) techniques were used to extract text relationships from 33+ million biomedical journal articles from PubMed and map relationships between genes, proteins, drugs, diseases, etc., into a knowledge graph. Cross-domain text mining, hub network analysis, and unsupervised learning rank aggregation were performed in SemNet 2.0 to predict the most relevant drug candidates to levodopa and PD using relevance-based HeteSim scores. The top predicted adjuvant PD therapies included ebastine, an antihistamine for perennial allergic rhinitis; levocetirizine, another antihistamine; vancomycin, a powerful antibiotic; captopril, an angiotensin-converting enzyme (ACE) inhibitor; and neramexane, an N-methyl-D-aspartate (NMDA) receptor agonist. Cross-domain text mining predicted that antihistamines exhibit the capacity to synergistically alleviate Parkinsonian symptoms when used with dopamine modulators like levodopa or levodopa-carbidopa. The relationship patterns among the identified adjuvant candidates suggest that the likely therapeutic mechanism(s) of action of antihistamines for combatting the multi-factorial PD pathology include counteracting oxidative stress, amending the balance of neurotransmitters, and decreasing the proliferation of inflammatory mediators. Finally, cross-domain text mining interestingly predicted a strong relationship between PD and liver disease.

Changes in Liver Lipidomic Profile in G2019S-LRRK2 Mouse Model of Parkinson's Disease

The identification of Parkinson's disease (PD) biomarkers has become a main goal for the diagnosis of this neurodegenerative disorder. PD has not only been intrinsically related to neurological problems, but also to a series of alterations in peripheral metabolism. The purpose of this study was to identify metabolic changes in the liver in mouse models of PD with the scope of finding new peripheral biomarkers for PD diagnosis. To achieve this goal, we used mass spectrometry technology to determine the complete metabolomic profile of liver and striatal tissue samples from WT mice, 6-hydroxydopamine-treated mice (idiopathic model) and mice affected by the G2019S-LRRK2 mutation in LRRK2/PARK8 gene (genetic model). This analysis revealed that the metabolism of carbohydrates, nucleotides and nucleosides was similarly altered in the liver from the two PD mouse models. However, long-chain fatty acids, phosphatidylcholine and other related lipid metabolites were only altered in hepatocytes from G2019S-LRRK2 mice. In summary, these results reveal specific differences, mainly in lipid metabolism, between idiopathic and genetic PD models in peripheral tissues and open up new possibilities to better understand the etiology of this neurological disorder.

Specific Challenges in Geriatric Cirrhosis and Hepatic Encephalopathy

As the world's population ages, diseases predominantly found in the elderly now overlap with diseases that were thought to be the purview of younger patients. This includes chronic liver disease, which affects more than 2 billion people worldwide. Owing to the obesity epidemic (and associated metabolic diseases), nonalcoholic fatty liver disease has become the most common cause of chronic liver disease and cirrhosis. A major complication of cirrhosis is hepatic encephalopathy (HE), which becomes challenging to diagnose in elderly patients. HE is usually included in the differential diagnosis of acute delirium but not of reversible dementias. To illustrate this point, we present 2 cases of older patients that were misdiagnosed as having dementia and Parkinson's disease or a parkinsonian syndrome but had contributions from cirrhosis. Both cognitive impairment and tremor resolved with treatment of HE.