Gastro-intestinal dysfunctions in Parkinson's disease (Review)

Lutein and the Underlying Neuroprotective Promise against Neurodegenerative Diseases

Alzheimer's disease (AD) and Parkinson's diseases (PD) are the two most common progressive neurodegenerative diseases with limited knowledge on their cause and, presently, have no cure. There is an existence of multiple treatment methods that target only the symptoms temporarily and do not stop the progression or prevent the onset of disease. Neurodegeneration is primarily attributed to the natural process of aging and the deleterious effects of heightened oxidative stress within the brain, whether via direct or indirect mechanisms. Emerging evidence suggests that certain nutritional aspects play a crucial role in the prevention and management of neurodegenerative diseases. Lutein, a dietary carotenoid, has been studied for its antioxidant properties for more than a decade with several applications against age-related macular degeneration. It is high antioxidant potential and selective accumulation in the brain makes it a versatile compound for combatting various neurodegenerative diseases. In this review, the studies exhibiting neuroprotective properties of lutein against neurodegenerative conditions, more specifically AD and PD in various model systems as well as clinical observations have been reviewed. Accordingly, the concerns associated with lutein absorption and potential strategies to improve its bioavailability have been discussed.

The missing piece of the puzzle - The key role of the dietitian in the management of Parkinson's disease

The current paradigm for the multidisciplinary management of Parkinson's Disease (PD) does not include regular nutritional assessment despite research showing that 90 % of people living with Parkinson's (PwP) lack access to basic dietetic services. Since many non-motor symptoms such as dysphagia, constipation and orthostatic hypotension and PD complications such as weight loss and sarcopenia can be improved through dietary intervention, dietitians are a critical missing piece of the PD management puzzle. This paper serves to review the role of dietitians and medical nutrition therapy in management of PD as well as a call to action for future studies to investigate improvement of nutritional status and quality of life for all PwP.

Helicobacter pylori infection and Parkinson's Disease: etiology, pathogenesis and levodopa bioavailability

Parkinson's disease (PD), a neurodegenerative disorder with an unknown etiology, is primarily characterized by the degeneration of dopamine (DA) neurons. The prevalence of PD has experienced a significant surge in recent years. The unidentified etiology poses limitations to the development of effective therapeutic interventions for this condition. Helicobacter pylori (H. pylori) infection has affected approximately half of the global population. Mounting evidences suggest that H. pylori infection plays an important role in PD through various mechanisms. The autotoxin produced by H. pylori induces pro-inflammatory cytokines release, thereby facilitating the occurrence of central inflammation that leads to neuronal damage. Simultaneously, H. pylori disrupts the equilibrium of gastrointestinal microbiota with an overgrowth of bacteria in the small intestinal known as small intestinal bacterial overgrowth (SIBO). This dysbiosis of the gut flora influences the central nervous system (CNS) through microbiome-gut-brain axis. Moreover, SIBO hampers levodopa absorption and affects its therapeutic efficacy in the treatment of PD. Also, H. pylori promotes the production of defensins to regulate the permeability of the blood-brain barrier, facilitating the entry of harmful factors into the CNS. In addition, H. pylori has been found to induce gastroparesis, resulting in a prolonged transit time for levodopa to reach the small intestine. H. pylori may exploit levodopa to facilitate its own growth and proliferation, or it can inflict damage to the gastrointestinal mucosa, leading to gastrointestinal ulcers and impeding levodopa absorption. Here, this review focused on the role of H. pylori infection in PD from etiology, pathogenesis to levodopa bioavailability.

Effectiveness of Continuous Dopaminergic Therapies in Parkinson's Disease: A Review of L-DOPA Pharmacokinetics/Pharmacodynamics

Background

Parkinson's disease (PD) is characterized by striatal dopamine deficiency. Since dopamine cannot cross the digestive and blood-brain barriers, its precursor, levodopa (L-DOPA), remains the mainstay of treatment. However, the significant pharmacokinetic (Pk) and pharmacodynamic (Pd) limitations of L-DOPA, combined with the severity of PD, may trigger motor and non-motor complications, for which continuous dopaminergic delivery therapies have been developed.

Objective

The aim of this study was to review the literature on the Pk/Pd limitations of L-DOPA and how current treatments of continuous dopaminergic administration ameliorate these problems, in order to identify the need for new therapeutic avenues.

Methods

A comprehensive literature search was carried out using PubMed and 75 articles were initially extracted. Following independent screening by two reviewers and consideration of eligibility, 10 articles were chosen for further analysis. Information concerning the Pk/Pd of L-DOPA was classified for each article.

Results

Pk/Pd problems notably include: (i) restricted digestive and cerebral absorption; (ii) unnecessary peripheral distribution; (iii) short half-life; (iv) age- and PD-induced decline of central aromatic L-amino acid decarboxylase; (v) misdistribution in many cells; and (vii) pulsatile stimulation of dopaminergic receptors. Current treatments only slightly ameliorate some of these problems.

Conclusions

Many Pk/Pd constraints are not resolved by existing continuous dopaminergic delivery therapies. This highlights the significant gap between these treatments and the ideal of continuous dopaminergic stimulation.

Risk factors for postoperative complications in patients with Parkinson disease: A single center retrospective cohort study

Surgical treatment for patients with Parkinson disease (PD) under general anesthesia has become frequent. PD is a significant predictor of postoperative complications. However, the factors that predict complications in patients with PD remain unknown. We retrospectively recruited patients with PD who underwent surgery between April 2015 and March 2019. The prevalence of postoperative complications was analyzed. We compared the patient characteristics, medical data, and surgical data between patients with and without postoperative complications. We also estimated the odds ratios (OR) for postoperative complications in patients with PD who underwent surgery. Sixty-five patients were enrolled. Eighteen patients presented with 22 complications, including urinary tract infections (UTI) (n = 3; 5%), pneumonia (n = 1; 2%), surgical site infections (SSI) (n = 3; 5%), postoperative delirium (POD) (n = 7; 10%), and others (n = 8; 12%). Four patients presented with 2 complications each. The operation time, the red blood cell transfusion and the rate of rotigotine usage were higher in patients with complications than those without (314 ± 197 min vs 173 ± 145 min, P = .006; 0 [0-560] mL vs 0 [0-0] mL, P = .02; 39% vs 6%, P = .003, respectively) (mean ± standard deviation or median [interquartile range]). Preoperative rotigotine usage (OR: 9.33; 95% confidential interval [CI]: 2.07-42.07; P = .004) was an independent risk factors for postoperative complications. The findings indicate that clinicians should closely monitor postoperative complications when patients with PD who have received transdermal dopamine agonists undergone longer time surgery.

[Lower gastrointestinal dysfunction in patients with Parkinson's disease]

OBJECTIVE

To assess the lower gastrointestinal tract dysfunction in patients with Parkinson's disease (PD) and to reveal its relationships with motor and non-motor symptoms.

MATERIAL AND METHODS

One hundred and eighteen patients with PD of I-III Hoehn and Yahr (H&Y) stages were studied using UPDRSI-IV, Sch&En, PDQ-39, MMSE, BDI, STAI-S and STAI-T, PFS-16, NMSQ, GSRS, BSFS, AUA. Body mass index and saliva amount and lacrimation (Schirmer's test) were assessed.

RESULTS

Constipation from mild to moderate intensity was present in 71.2% of the patients; predominantly mild diarrhea occurred in 27.9%; alternations of diarrhea with the difficulty in intestine emptying were observed in 25.4%. We found significant correlations of constipation with the following parameters: Sch&En scales (rS=-0.291) and PDQ-39 (rS=0.478), patient's age (rS=0.275), H&Y stage (rS=0.2604), UPDRS (rS=0.254), axial motor symptoms of parkinsonism, and a number of affective and autonomic disorders, most of which were partly dopamine-resistant. Diarrhea did not affect the quality of patient's life, or depend on age, PD stage, main digital and non-motor symptoms, but directly correlated with the severity of constipation (rS=0.263) and other gastrointestinal disorders. There were no effects of dopaminergic therapy, including levodopa, dopamine-receptor-agonists, and amantadine, on the lower gastrointestinal tract dysfunction.

CONCLUSION

Dysfunction of the lower gastrointestinal tract (predominantly from mild to moderate intensity) was detected in most PD patients of I-III stages. Our data indicate a complex pathogenesis of the PD impaired bowel emptying, involving degeneration of non-dopaminergic structures, and the predominant influence of concomitant diseases and inadequate laxative therapy on the formation of diarrhea syndrome in PD.

Synucleinopathies

The α-synucleinopathies include pure autonomic failure, multiple system atrophy, dementia with Lewy bodies, and Parkinson disease. The past two decades have witnessed significant advances in the diagnostic strategies and symptomatic treatment of motor and nonmotor symptoms of the synucleinopathies. This chapter provides an in-depth review of the pathophysiology, pathology, genetic, epidemiology, and clinical and laboratory autonomic features that distinguish the different synucleinopathies with an emphasis on autonomic failure as a common feature. The treatment of the different synucleinopathies is discussed along with the proposal for multidisciplinary, individualized care models that optimally address the various symptoms. There is an urgent need for clinical scientific studies addressing patients at risk of developing synucleinopathies and the investigation of disease mechanisms, biomarkers, potential disease-modifying therapies, and further advancement of symptomatic treatments for motor and nonmotor symptoms.

Effect of Berberine Hydrochloride on the Diversity of Intestinal Flora in Parkinson's Disease Patients

This study aimed to investigate the effect of berberine hydrochloride on the diversity of intestinal flora in patients with Parkinson's disease (PD). Prospectively selected 68 PD patients, admitted to our hospital from April 2021 to June 2021, were randomly assigned to an observation group and a control group (n = 34 per group). Patients in the control group were given conventional treatment in accordance with Parkinson's diagnosis and treatment guidelines. Patients in the observation group were administered berberine hydrochloride besides the treatment in the control group. After continuous treatment for 3 months, the enzyme-linked immunosorbent assay was applied to determine interleukin-8 (IL-8), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) levels. High-throughput sequencing technology was employed to perform DNA sequencing on the 16S rRNA genes of all bacteria in stool samples before and after treatment in the two groups to analyze the distribution of intestinal flora. After treatment, the levels of IL-8, IL-6, and TNF-α were lower in the observation group than those in the control group (P < 0.05). Regarding intestinal flora, the Chao index, Ace index, and Shannon index were higher in the observation group than those in the control group. The Simpson index was lower in the observation group than that of the control group (P < 0.05). The principal component analysis chart analysis exhibited that the overall structure of the intestinal flora was quite different between the observation and the control groups after treatment. Berberine hydrochloride can improve the disorder of intestinal flora in PD patients and suppress the expression of inflammatory factors.

Association between irritable bowel syndrome and Parkinson's disease: A systematic review and meta-analysis

BACKGROUND

Growing evidence suggests that irritable bowel syndrome (IBS) and Parkinson's disease (PD) share similar pathological mechanisms and risk factors.

METHODS

We performed a systematic review and meta-analysis of the evidence for a relationship between IBS and PD. Risk estimates from individual studies were pooled using random-effects models.

RESULTS

Six articles involving 58,645 patients with PD were included in our meta-analysis. The overall risk for PD in IBS patients was significantly higher than that in the general population (odds ratio [OR], 1.5; 95% confidence interval [CI], 1.29-1.75; p < .001). Subgroup analysis revealed no significant differences in risk between men (OR = 1.47, 95% CI: 1.3-1.67; p < .001) and women (OR = 1.51, 95% CI: 1.29-1.75; p < .001); however, older (≥65 years) IBS patients (OR = 1.44, 95% CI: 1.3-1.59; p < .001) may be at higher risk for PD than younger (40-64 years) patients (OR = 1.32, 95% CI: 1.05-1.64; p = .017).

CONCLUSION

Overall, the PD risk was higher in IBS patients than others, indicating that the intestinal disorder may serve as a warning sign for PD.

Personalized Assessment of Insomnia and Sleep Quality in Patients with Parkinson's Disease

Sleep disturbances are more common in patients with Parkinson’s disease (PD) than in the general population and are considered one of the most troublesome symptoms by these patients. Insomnia represents one of the most common sleep disturbances in PD, and it correlates significantly with poor quality of life. There are several known causes of insomnia in the general population, but the complex manifestations that might be associated with PD may also induce insomnia and impact the quality of sleep. The treatment of insomnia and the strategies needed to improve sleep quality may therefore represent a challenge for the neurologist. A personalized approach to the PD patient with insomnia may help the clinician to identify the factors and comorbidities that should also be considered in order to establish a better individualized therapeutic plan. This review will focus on the main characteristics and correlations of insomnia, the most common risk factors, and the main subjective and objective methods indicated for the assessment of insomnia and sleep quality in order to offer a concise guide containing the main steps needed to approach the PD patient with chronic insomnia in a personalized manner.

Gut-Brain Axis as a Pathological and Therapeutic Target for Neurodegenerative Disorders

Human lifestyle and dietary behaviors contribute to disease onset and progression. Neurodegenerative diseases (NDDs), considered multifactorial disorders, have been associated with changes in the gut microbiome. NDDs display pathologies that alter brain functions with a tendency to worsen over time. NDDs are a worldwide health problem; in the US alone, 12 million Americans will suffer from NDDs by 2030. While etiology may vary, the gut microbiome serves as a key element underlying NDD development and prognosis. In particular, an inflammation-associated microbiome plagues NDDs. Conversely, sequestration of this inflammatory microbiome by a correction in the dysbiotic state of the gut may render therapeutic effects on NDDs. To this end, treatment with short-chain fatty acid-producing bacteria, the main metabolites responsible for maintaining gut homeostasis, ameliorates the inflammatory microbiome. This intimate pathological link between the gut and NDDs suggests that the gut-brain axis (GBA) acts as an underexplored area for developing therapies for NDDs. Traditionally, the classification of NDDs depends on their clinical presentation, mostly manifesting as extrapyramidal and pyramidal movement disorders, with neuropathological evaluation at autopsy as the gold standard for diagnosis. In this review, we highlight the evolving notion that GBA stands as an equally sensitive pathological marker of NDDs, particularly in Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis and chronic stroke. Additionally, GBA represents a potent therapeutic target for treating NDDs.

Intestinal Permeability, Dysbiosis, Inflammation and Enteric Glia Cells: The Intestinal Etiology of Parkinson’s Disease

The scientific and medical communities are becoming more aware of the substantial relationship between the function of the central nervous system (CNS) and the state of the gut environment. Parkinson's disease (PD) is a neurodegenerative disorder that affects the nigrostriatal pathway in the midbrain, presenting not only motor symptoms but also various non-motor manifestations, including neuropsychiatric symptoms and gastrointestinal (GI) symptoms. Over time, our knowledge of PD has progressed from the detection of midbrain dopaminergic deficits to the identification of a multifaceted disease with a variety of central and peripheral manifestations, with increased attention to the intestinal tract. Accumulating evidence has revealed that intestinal disorders are not only the peripheral consequence of PD pathogenesis, but also the possible pathological initiator decades before it progresses to the CNS. Here, we summarized recent research findings on the involvement of the intestinal environment in PD, with an emphasis on the involvement of the intestinal barrier, microbiome and its metabolites, inflammation, and enteric glial cells