Impaired gastric emptying of a solid test meal in patients with Parkinson's disease using 13C-sodium octanoate breath test

Gastric-filling ultrasonography to evaluate gastric motility in patients with Parkinson's disease

Background

Delayed gastric emptying is a common non-motor symptom of Parkinson's disease (PD). However, there is currently no objective evaluation and diagnostic method for this condition.

Objectives

The purpose of this study was to evaluate the feasibility of gastric-filling ultrasonography for gastric motility in patients with PD and the relationship between gastric dynamics and gastrointestinal symptoms and motor symptoms of PD.

Design setting and patients

We performed a case-control study with 38 patients with PD and 34 healthy controls.

Methods

All patients underwent a 120-min ultrasonography examination using a 500-ml semi-liquid test meal. We determined the antral contraction amplitude (ACA), the antrum contraction frequency (ACF), the motility index (MI), and the gastric antral cross-sectional area (CSA). We acquired the CSA at six time points: fasting for 12 h (T0), immediately after drinking the semi-liquid test meal (T1); and at 30 (T30), 60 (T60), 90 (T90), and 120 (T120) min. We calculated the gastric emptying rate (GER) at different time points by using the CSA. We compared the GER between the groups and evaluated the correlation between the GER and gastrointestinal symptoms and motor symptoms of PD.

Results

The MI and ACF were significantly lower in the PD group compared with the control group (P < 0.05). The GER at T30 and the ACA showed no significant difference between the groups (P > 0.05). At different time points, the GER was significantly different between the PD and control groups (P < 0.001). There was no significant association between the GER and gastrointestinal symptoms; none of them were risk factors for impaired gastric emptying (odds ratio > 1). The GER was negatively correlated with the severity of PD motor symptoms (P < 0.05).

Conclusion

Patients with PD had significantly delayed gastric emptying, which was negatively correlated with the severity of PD motor symptoms. Measuring gastric emptying by gastric-filling ultrasound had good diagnostic value in clinical screening for delayed gastric motility in patients with PD.

Clinical Trial Registration

https://www.chictr.org.cn/showproj.html?proj=126304.

Metabolomic analysis of serum short-chain fatty acid concentrations in a mouse of MPTP-induced Parkinson's disease after dietary supplementation with branched-chain amino acids

The gut microbiota and microbial metabolites influence the enteric nervous system and the central nervous system via the microbial-gut-brain axis. Increasing body of evidence suggests that disturbances in the metabolism of peripheral branched-chain amino acids (BCAAs) can contribute to the development of neurodegenerative diseases through neuroinflammatory signaling. Preliminary research has shown that longitudinal changes in serum amino acid levels in mouse models of Parkinson's disease (PD) are negatively correlated with disease progression. Therefore, the aim of the present study was to determine the changes in serum levels of short-chain fatty acids (SCFAs) in a mouse model of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD after dietary BCAA supplementation. In our research, gas chromatography-mass spectrometry was used to detect serum SCFA concentrations. The data were then analyzed with principal component analysis and orthogonal partial least squares discriminant analysis. Finally, the correlations of serum SCFA levels with gut and motor function in MPTP-induced PD mice were explored. Propionic acid, acetic acid, butyric acid, and isobutyric acid concentrations were elevated in MPTP + H-BCAA mice compared with MPTP mice. Propionic acid concentration was increased the most, while the isovaleric acid concentration was decreased. Propionic acid concentration was positively correlated with fecal weight and water content and negatively correlated with the pole-climbing duration. In conclusion, these results not only suggest that propionic acid may be a potential biomarker for PD, but also indicate the possibility that PD may be treated by altering circulating levels of SCFA.

A novel MRI-based three-dimensional model of stomach volume, surface area, and geometry in response to gastric filling and emptying

BACKGROUND

Gastric motility and accommodation have a critical role in maintaining normal gastrointestinal homeostasis. Different modalities can be adopted to quantify those processes, that is, scintigraphy to measure emptying time and intragastric Barostat for accommodation assessment. However, magnetic resonance imaging (MRI) can assess the same parameters noninvasively without ionizing radiation. Our study aimed to develop a detailed three-dimensional (3D) MRI model of the stomach to describe gastric volumes, surface areas, wall tension distribution, and interobserver agreement.

METHODS

Twelve healthy volunteers underwent an MRI protocol of six axial T2-weighted acquisitions. Each dataset was used to construct a 3D model of the stomach: First, the volumes of the whole stomach, gastric liquid, and air were segmented. After landmark placing, a raw 3D model was generated from segmentation data. Subsequently, irregularities were removed, and the model was divided into compartments. Finally, surface area and 3D geometry parameters (inverse curvatures) were extracted. The inverse curvatures were used as a proxy for wall tension distribution without measuring the intragastric pressure.

KEY RESULTS

The model was able to describe changes in volume and surface geometry for each compartment with a distinct pattern in response to filling and emptying. The surface tension was distributed nonhomogeneously between compartments and showed dynamical changes at various time points.

CONCLUSION & INFERENCES

The presented model offers a detailed tool for evaluating gastric volumes, surface geometry, and wall tension in response to filling and emptying and will provide insights into gastric emptying and accommodation in diseases such as diabetic gastroparesis.

Pre-induction Ultrasonographic Evaluation of Gastric Residual Volume in Elective Gastrointestinal Cancer Surgeries

Pulmonary aspiration of gastric contents during elective surgery remains a major cause of airway-related mortality and morbidity. The preoperative fasting times for solids and liquids have been standardized across various anesthesia society guidelines. Enhanced Recovery After Surgery (ERAS) guidelines now advocate liberal clear fluid intake with carbohydrate loading up to 2 h preoperatively. The aim of the study was to assess whether practicing both ASA fasting guidelines and ERAS protocol makes the patients prone to a full stomach. The supine position standard curvilinear ultrasound probe (2-5 MHz) with Sonosite M-Turbo ©system was used to obtain the images. Gastric residual volume (GRV) was derived from the cross-sectional area (CSA) using the Perlas and colleagues model. A total of 102 patients were recruited and analyzed. The mean age and BMI were 50.65 years ± 13.35 years and 22.23 kg/m² ± 3.7 kg/m², respectively. A total of four patients (3.92%) had gastric volume > 1.5 ml/kg; out of these four patients, three were female and one was male. We did not observe any case of pulmonary aspiration in any of our patients. In conclusion, even though for elective surgeries, the current fasting guidelines are adequate, these findings cannot be extrapolated to patients with risk factors for high gastric residual volume where further studies need to be performed.

Gut microorganisms and neurological disease perspectives

The gastrointestinal tract of every healthy human consists of a unique set of gut microbiota that collectively harbors a diverse and complex community of over 100 trillion microorganisms, including bacteria, viruses, archaea, protozoa and fungi. Gut microbes have a symbiotic relationship with our body. The composition of the microbiota is shaped early in life by gut maturation, which is influenced by several factors. Intestinal bacteria are crucial in maintaining immune and metabolic homeostasis and protecting against pathogens. Dysbiosis of gut microbiota is associated not only with intestinal disorders but also with extraintestinal diseases such as metabolic and neurological disorders. In this review, the authors examine different studies that have revealed the possible hypotheses and links in the development of neurological disorders associated with the gut microbiome.

Bilateral Subthalamic Nucleus Deep Brain Stimulation Improves Gastric Emptying Time in Parkinson Disease

BACKGROUND

It is well-established that deep brain stimulation (DBS) can improve motor function in those with Parkinson disease (PD); however, its effects on gastrointestinal disorders remain unclear.

METHODS

From January 2019 to December 2020, 26 patients with PD who had undergone subthalamic nucleus (STN) DBS were included in our study. The evaluated items included the pre- and postoperative dose of levodopa, Unified Parkinson's Disease Rating Scale, part III, scores with and without medication and stimulation, and gastric emptying time (expressed as the peak time of carbon-¹³C dioxide excretion in the ¹³C-acetate breath test). Sex-, age-, and body weight-matched controls were recruited to test the gastric emptying time in healthy individuals.

RESULTS

All the patients benefited from DBS. The Unified Parkinson's Disease Rating Scale, part III, scores had decreased from 48.5 ± 13.77 to 25.23 ± 8.59 without medication and 31.23 ± 11.4 to 13.92 ± 5.27 with medication. The levodopa equivalent dose had decreased from 1009.8 ± 291 mg to 707.65 ± 193.79 mg. The gastric emptying time was significantly prolonged in the patients with PD before DBS compared with the healthy control group (29.23 ± 6.58 minutes) and had improved to 35.19 ± 10.14 minutes with medication and 38.07 ± 11.17 minutes without medication after 3 months of STN stimulation. At 6 months postoperatively, the gastric emptying time was 32.3 ± 10.02 minutes without medication and 33.84 ± 10.79 minutes with medication.

CONCLUSIONS

A delayed gastric emptying time is associated with greater PD severity. Antiparkinsonian medications did not affect gastric emptying in patients with PD. STN DBS can improve both movement function and gastrointestinal motility in patients with PD in the long term. The exact mechanism by which DBS improves gastric emptying requires further exploration.

Role of microbiota-derived short-chain fatty acids in nervous system disorders

During the past decade, accumulating evidence from the research highlights the suggested effects of bacterial communities of the human gut microbiota and their metabolites on health and disease. In this regard, microbiota-derived metabolites and their receptors, beyond the immune system, maintain metabolism homeostasis, which is essential to maintain the host's health by balancing the utilization and intake of nutrients. It has been shown that gut bacterial dysbiosis can cause pathology and altered bacterial metabolites' formation, resulting in dysregulation of the immune system and metabolism. The short-chain fatty acids (SCFAs), such as butyrate, acetate, and succinate, are produced due to the fermentation process of bacteria in the gut. It has been noted remodeling in the gut microbiota metabolites associated with the pathophysiology of several neurological disorders, such as Alzheimer's disease, multiple sclerosis, Parkinson's disease, amyotrophic lateral sclerosis, stress, anxiety, depression, autism, vascular dementia, schizophrenia, stroke, and neuromyelitis optica spectrum disorders, among others. This review will discuss the current evidence from the most significant studies dealing with some SCFAs from gut microbial metabolism with selected neurological disorders.

Therapeutic Strategies to Treat or Prevent Off Episodes in Adults with Parkinson's Disease

Parkinson's disease is a chronic, neurodegenerative disease, which manifests with a mixture of motor, cognitive and behavioural symptoms. Levodopa is the most effective antiparkinsonian treatment to date, although chronic use engenders a mixture of complications in a substantial proportion of patients. Amongst these is the occurrence of episodes of worsening symptoms-'off' phenomena. These episodes can manifest with either motor or non-motor symptoms or a combination of these features and have been found to have profound impacts on patients' quality of life. Although preventative measures are poorly evidenced, avoiding excessive total daily levodopa intake in selected populations that are deemed to be of a higher risk for developing these episodes warrants further exploration. Methods to improve levodopa bioavailability and delivery to the brain are currently available and are of value in addressing these episodes once they have become established. These include modifications to levodopa formulations as well as the use of complimentary agents that improve levodopa bioavailability. The deployment of device-assisted approaches is a further dimension that can be considered in addressing these debilitating episodes. This review summarises the clinical manifestations of 'off' phenomena and the current approaches to treat them. Although we briefly discuss clinical advances on the horizon, the predominant focus is on existing, established treatments.

Gastrointestinal dysfunction in the synucleinopathies

Interest in gastrointestinal dysfunction in Parkinson's disease has blossomed over the past 30 years and has generated a wealth of investigation into this non-motor aspect of the disorder, research that has encompassed its pathophysiology, its clinical features, and its impact on quality of life. The question of gastrointestinal dysfunction in the other synucleinopathies has not received nearly as much attention, but information and knowledge are growing. In this review, the current knowledge, controversies, and gaps in our understanding of the pathophysiology of gastrointestinal dysfunction in Parkinson's disease and the other synucleinopathies will be addressed, and extended focus will be directed toward the clinical problems involving saliva management, swallowing, gastric emptying, small intestinal function, and bowel function that are so problematic in these disorders.

Gastric Motility in Parkinson's Disease is Altered Depending on the Digestive Phase and Does Not Correlate with Patient-Reported Motor Fluctuations

Background:

Altered gastric motility is a frequent non-motor symptom of Parkinson’s disease (PD). It has been hypothesized that disturbed gastric motility contributes to motor fluctuations in PD due to an erratic gastro-duodenal transport and an unpredictable absorption of drugs.

Objective:

We investigated whether patient-reported fluctuations are associated with parameters of gastric motility visualized by real-time magnetic resonance imaging (MRI) of the stomach.

Methods:

We analyzed real-time MRI-scans of the stomach after an overnight fasting period in 16 PD patients and 20 controls. MRI was performed 1) in the fasting state, 2) directly after a test meal, and 3) 4 hours postprandially. Gastric motility indices were calculated and compared between groups.

Results:

MRI showed an attenuated gastric motility in PD patients compared to controls. The difference was most obvious in the early postprandial phase. Gastric motility was not associated with patient-reported motor fluctuations. Using an iron-containing capsule we were able to retrace retention of drugs in the stomach.

Conclusion:

The results of this study stress the importance of considering the phase of digestion when investigating gastric motility in PD. Despite theoretical considerations, we did not find robust evidence for an association between MRI parameters of gastric motility and patient-reported motor fluctuations. For future studies that aim to investigate gastric motility in PD by MRI, we suggest multiple short-time MRIs to better track the whole gastro-duodenal phase in PD. Such an approach would also allow to retrace the retention of drugs in the stomach as shown by our approach using an iron-containing capsule.

Clinical implications of gastric complications on levodopa treatment in Parkinson's disease

Disorders of the gastrointestinal (GI) tract are common and distressing nonmotor symptoms of Parkinson's disease (PD) that can adversely affect levodopa absorption and lead to OFF periods, also known as motor fluctuations. Gastroparesis, which is primarily defined as delayed gastric emptying (DGE), and Helicobacter pylori infection, which is present with increased frequency in PD, are among the most common and important GI disorders reported in PD that may impair oral levodopa absorption and increase OFF time. Symptoms of gastroparesis include nausea, vomiting, postprandial bloating, fullness, early satiety, abdominal pain, and weight loss. DGE has been reported in a substantial fraction of individuals with PD. Symptoms of H. pylori infection include gastritis and peptic ulcers. Studies have found that DGE and H. pylori infection are correlated with delayed peak levodopa plasma levels and increased incidence of motor fluctuations. Therapeutic strategies devised to minimize the potential that gastric complications will impair oral levodopa absorption and efficacy in PD patients include treatments that circumvent the GI tract, such as apomorphine injection, levodopa intestinal gel delivery, levodopa inhalation powder, and deep brain stimulation. Other strategies aim at improving gastric emptying in PD patients, primarily including prokinetic agents.

From medications to surgery: advances in the treatment of motor complications in Parkinson's disease

Motor complications are responsible for the large burden of disability and poor quality of life in Parkinson’s disease (PD). The pulsatile nature of stimulation with oral dopaminergic therapies due to relatively short pharmacokinetic profiles and dysfunctional gastrointestinal absorption have been attributed to the development of PD motor complications. In this review, we will provide an overview of the pharmacologic and surgical therapies currently available and under investigation for the treatment of motor fluctuations and dyskinesia.

Gastric dysmotility in Parkinson's disease is not caused by alterations of the gastric pacemaker cells

The enteric nervous system is involved in the pathology of Parkinson´s disease and patients frequently have symptoms related to delayed gastric emptying. However, the pathophysiology of gastric dysmotility is yet not well understood. The objective of this study was to assess interdigestive gastric motility in Parkinson´s disease. Using an electromagnetic capsule system, the dominant gastric contraction frequency (primary outcome measure) and the gastric transit time were assessed in 16 patients with Parkinson´s disease and 15 young healthy controls after a fasting period of 8 h. Motor and non-motor symptoms were assessed using the Movement Disorder Society Unified Parkinson´s Disease Rating Scale III (MDS-UPDRS III), the Non-Motor Symptoms Questionnaire (NMS-Quest), and Hoehn & Yahr staging. The Gastroparesis Cardinal Symptom Index was used to record symptoms related to delayed gastric emptying. In healthy controls and patients with Parkinson's disease, the dominant contraction frequency was 3.0 cpm indicating normal function of interstitial cells of Cajal. In patients with Parkinson's disease, the gastric transit time was longer than in younger controls (56 vs. 21 min). The dominant contraction frequency and gastric transit time did not correlate with age, disease duration, Hoehn & Yahr stage, levodopa equivalent daily dose, MDS-UPDRS III, NMS-Quest, and Gastroparesis Cardinal Symptom Index. Changes of gastric motility in Parkinson´s disease are not caused by functional deficits of the gastric pacemaker cells, the interstitial cells of Cajal. Therefore, gastroparesis in Parkinson's disease can be attributed to disturbances in neurohumoral signals via the vagus nerve and myenteric plexus.

Parkinson's Disease and Current Treatments for Its Gastrointestinal Neurogastromotility Effects

PURPOSE OF REVIEW

Gastrointestinal disturbances are seen in nearly all patients with Parkinson's disease and lead to impaired quality of life, affect drug pharmacodynamics, and potentially worsen patient's existing motor fluctuations, leading to further disability. Recent evidence links abnormal accumulations of α-synuclein aggregates in the periphery (gut) as seen in the cortex which causes dysfunctions impacting every level of the gastrointestinal tract from the esophagus, to the stomach, small bowel, colon, and rectum and can even predate the onset of the central neurologic disorder itself. Many treatments exist for the clinical phenotypes that result from the autonomic dysfunction and neuropathy involved in this neurodegenerative disorder. The treatments for the gut dysfunction seen in Parkinson's disease (PD) depend on the specific area of the gastrointestinal tract affected. For dysphagia, behavioral therapies with speech pathology, neuromuscular electrical stimulation, or botulinum toxin injection may be helpful. For gastroparesis, domperidone may serve as an antiemetic while also blunting the hypotensive potential of Levodopa while new treatments such as ghrelin agonists may prove beneficial to help appetite, satiety, gastric emptying in those with constipation, and even improve constipation. Antibiotics such as rifaximin with poor systemic absorption may be used to treat small bacterial overgrowth also found in those with PD while the benefits of probiotics is yet to be determined. Finally, constipation in PD can be a reflection of pelvic floor dyssynergia, slow transit constipation, or both, thus treatments targeting the specific anorectal dysfunction is necessary for better outcomes.

Gastrointestinal Dysfunction in Parkinson's Disease

PURPOSE OF REVIEW

During the past 25 years, there has been an explosion of information regarding the occurrence of gastrointestinal dysfunction in Parkinson's disease. In this review, the clinical features of gastrointestinal dysfunction in Parkinson's disease will be described and information regarding the potential role of the enteric nervous system and the gut microbiome in the genesis of Parkinson's disease will be addressed.

RECENT FINDINGS

Recognition is growing regarding the role that gastroparesis and small intestinal dysfunction may play in Parkinson's disease, especially with regard to erratic responses to anti-Parkinson medication. The presence of enteric nervous system involvement in Parkinson's disease is now well established, but whether the enteric nervous system is the starting point for Parkinson's disease pathology remains a source of debate. The potential role of the gut microbiome also is beginning to emerge. Gastrointestinal dysfunction is a prominent nonmotor feature of Parkinson's disease and dysfunction can be found along the entire length of the gastrointestinal tract. The enteric nervous system is clearly involved in Parkinson's disease. Whether it is the initial source of pathology is still a source of controversy. There also is growing recognition of the role that the gut microbiome may play in Parkinson's disease, but much more research is needed to fully assess this aspect of the disorder.

Gastric emptying in Parkinson's disease - A mini-review

Patients with Parkinson's disease (PD) experience a range of non-motor symptoms, including constipation and other gastrointestinal problems. These symptoms are sometimes present in the prodromal disease phase. An improved understanding of the underlying pathophysiology is needed considering that PD has been hypothesized to originate in the gut. Delayed gastric emptying time (GET) is often listed as a prevalent gastrointestinal symptom in PD, but the true prevalence is controversial. The aim of this short review was to investigate if GET in PD is dependent on the applied measuring methodology. A systemic search of Pubmed identified 15 relevant studies, including six using gold standard method gastric scintigraphy and nine using ¹³C-octanoate breath tests. Overall, gastric scintigraphy studies showed a non-significant GET delay (standardized mean difference (SMD) 0.42) in PD patients. After exclusion of one outlier study, GET was significantly increased (SMD 0.59). In contrast, highly significant GET delay (SMD 1.70) was seen in breath test studies. A limitation of the meta-analyses was reuse of the same control group in some studies. In summary, the marked GET delay observed in breath test studies is not confirmed by gold standard gastric scintigraphy studies. This discrepancy can perhaps be explained by breath test being an indirect GET measure, depending not only on mechanic stomach emptying but also intestinal absorption and liver metabolism. Thus, multi-modality studies under standardized conditions are needed to elucidate the prevalence and severity of gastric dysmotility in PD, along with contributions from other factors including intestinal absorption and permeability.

Progression of Parkinson's disease is associated with gut dysbiosis: Two-year follow-up study

BACKGROUND

We previously reported gut dysbiosis in patients with Parkinson's disease (PD).

OBJECTIVE

The aim of this study is to examine whether gut dysbiosis correlates with the progression of PD.

METHODS

We examined changes in gut microbiota and demographic features in 2 years in 36 PD patients.

RESULTS

A change of total UPDRS scores in 2 years was predicted by the counts of Bifidobacterium and Atopobium cluster at year 0 with a correlation coefficient of 0.52. Correlation analysis additionally revealed that low counts of Bifidobacterium and Bacteroides fragilis at year 0 were associated with worsening of UPDRS I scores in 2 years. In addition, low counts of Bifidobacterium at year 0 were associated with worsening of hallucinations/delusions in 2 years. Similarly, low counts of B. fragilis at year 0 were associated with worsening of motivation/initiative in 2 years. The patients were evenly divided into the deteriorated and stable groups based on the degree of worsening of total UPDRS scores. The deteriorated group had lower counts of Bifidobacterium, B. fragilis, and Clostridium leptium than the stable group at year 0 but not at year 2, suggesting that the deteriorated group may demonstrate accelerated lowering of these bacteria at year 0.

CONCLUSIONS

The total counts of intestinal bacterial decrease in the course of PD progression. Temporal profiles of lowering of bacterial counts are likely to be different from bacteria to bacteria, and also between the deteriorating and stable groups, which may be able to be exploited to differentiate patients with rapidly and slowly progressive PD pathology.

Imaging Parkinson's disease below the neck

Parkinson's disease is a systemic disorder with widespread and early α-synuclein pathology in the autonomic and enteric nervous systems, which is present throughout the gastrointestinal canal prior to diagnosis. Gastrointestinal and genitourinary autonomic symptoms often predate clinical diagnosis by several years. It has been hypothesized that progressive α-synuclein aggregation is initiated in hyperbranched, non-myelinated neuron terminals, and may subsequently spread via retrograde axonal transport. This would explain why autonomic nerves are so prone to formation of α-synuclein pathology. However, the hypothesis remains unproven and in vivo imaging methods of peripheral organs may be essential to study this important research field. The loss of sympathetic and parasympathetic nerve terminal function in Parkinson's disease has been demonstrated using radiotracers such as 123I-meta-iodobenzylguanidin, 18F-dopamine, and 11C-donepezil. Other radiotracer and radiological imaging methods have shown highly prevalent dysfunction of pharyngeal and esophageal motility, gastric emptying, colonic transit time, and anorectal function. Here, we summarize the methodology and main findings of radio-isotope and radiological modalities for imaging peripheral pathology in Parkinson's disease.

Delayed Gastric Emptying in Advanced Parkinson Disease: Correlation With Therapeutic Doses

INTRODUCTION

Gastrointestinal dysfunction is often described in patients with Parkinson disease (PD), and gastrointestinal symptoms are usually attributed to gastroparesis. The consequent delayed gastric emptying (GE) may be an important pharmacokinetic mechanism underlying some of the response fluctuations that develop after long-term levodopa (L-dopa) therapy.The aim of this prospective study was to assess GE time by a liquid meal scintigraphy, in PD patients, and to correlate them with demographic, clinical, and therapeutic data.

METHODS

Scintigraphy with radiolabeled albumin nanocolloids added to acidified orange juice was performed in 51 consecutive PD patients 1 hour after their usual dopaminergic therapy first dose and after a 12-hour fast. Demographic, neurologic, gastrointestinal, and pharmacologic data were collected.

RESULTS

Fifty-one patients were divided into 2 groups using the cutoff point obtained in normal subjects (40 minutes): group 1 included 29 patients with GE T½ of 27.60 ± 7.30 minutes (normal), group 2 showed a GE T½ of 84.90 ± 53.80 minutes (delayed). The most striking significant difference between the 2 groups was the dopa-decarboxylase inhibitor mean dose that was significantly higher in the group of patients with delayed GE (201.32 ± 97.26 vs 127.65 ± 79.74; P = 0.005).

CONCLUSIONS

The impairment of gastric motility, frequently represented in PD patients, occurs in approximately 42% of patients with motor complications. A mechanism that may explain the GE delay is the effect of L-dopa on dopaminergic receptors in the stomach. Therefore, the dosage of dopa-decarboxylase inhibitor, increasing the L-dopa concentration, may contribute to GE delay and its consequent effect on drug delivery and efficacy.

The need for non-oral therapy in Parkinson's disease; a potential role for apomorphine

In the course of Parkinson's disease (PD), oral medication may lose its effectiveness due to several reasons, like dysphagia, impaired absorption from the gastro-intestinal tract and delayed emptying of the stomach. If these problems occur, a non-oral therapy should be considered. Examples of non-oral therapies are transdermal patches, (e.g. rotigotine) which may overcome motor and nonmotor nighttime problems, and may serve as well to treat daytime response-fluctuations, if oral therapies fail to do so. Other options are injections with apomorphine to treat early morning dystonia and random off-periods during daytime, as well as continuously infused subcutaneous apomorphine for random fluctuations in PD patients. Low-dose apomorphine infusions also may be useful in the peri-operative phase, when PD patients may not be able to swallow oral medication. Finally, levodopa-carbidopa intestinal gel (LCIG) infusions or DBS have shown to be effective non-oral options to treat PD patients adequately, if they are not properly controlled by oral options.

Non-oral dopaminergic therapies for Parkinson's disease: current treatments and the future

Dysfunction of the gastrointestinal tract has now been recognized to affect all stages of Parkinson’s disease (PD). The consequences lead to problems with absorption of oral medication, erratic treatment response, as well as silent aspiration, which is one of the key risk factors in developing pneumonia. The issue is further complicated by other gut abnormalities, such as small intestinal bacterial overgrowth (SIBO) and an altered gut microbiota, which occur in PD with variable frequency. Clinically, these gastrointestinal abnormalities might be associated with symptoms such as nausea, early-morning “off”, and frequent motor and non-motor fluctuations. Therefore, non-oral therapies that avoid the gastrointestinal system seem a rational option to overcome the problems of oral therapies in PD. Hence, several non-oral strategies have now been actively investigated and developed. The transdermal rotigotine patch, infusion therapies with apomorphine, intrajejunal levodopa, and the apomorphine pen strategy are currently in clinical use with a few others in development. In this review, we discuss and summarize the most recent developments in this field with a focus on non-oral dopaminergic strategies (excluding surgical interventions such as deep brain stimulation) in development or to be licensed for management of PD.

Gastrointestinal Dysfunction in Patients with Duchenne Muscular Dystrophy

Background

In adult patients with Duchenne muscular dystrophy (DMD) life-threatening constipation has been reported. Since gastrointestinal function in DMD has not been rigorously studied we investigated objective and subjective manifestations of gastrointestinal disturbances in DMD patients.

Methods

In 33 patients with DMD, age 12–41 years, eating behavior and gastrointestinal symptoms were evaluated by questionnaires. Gastric emptying half time (T_1/2) and oro-cecal transit time (OCTT) were evaluated by analyzing ¹³CO₂ exhalation curves after ingestion of ¹³C labeled test meals. Colonic transit time (CTT) was measured by abdominal radiography following ingestion of radiopaque markers.

Results

The median (quartiles) T_1/2 was 187 (168, 220) minutes, the OCTT was 6.3 (5.0, 7.9) hours, both substantially longer than normal data (Goetze 2005, T_1/2: 107±10; Geypens 1999, OCTT 4.3±0.1 hours). The median CTT was 60 (48, 82) hours despite extensive use of laxative measures (Meier 1995, upper limit of normal: 60 hours). T_1/2 and OCTT did not correlate with symptoms evaluated by the Gastroparesis Cardinal Symptom Index (GCSI) (Spearman r = -0.3, p = 0.1; and r = -0.15, p = 0.4, respectively). CTT was not correlated with symptoms of constipation assessed by ROME III criteria (r = 0.12, p = 0.5).

Conclusions

DMD patients have a markedly disturbed gastrointestinal motor function. Since objective measures of impaired gastrointestinal transport are not correlated with symptoms of gastroparesis or constipation our findings suggest that measures assuring adequate intestinal transport should be taken independent of the patient’s perception in order to prevent potentially life threatening constipation, particularly in older DMD patients.

Short chain fatty acids and gut microbiota differ between patients with Parkinson's disease and age-matched controls

BACKGROUND

Patients with Parkinson's disease (PD) frequently have gastrointestinal symptoms (e.g. constipation) and exhibit the PD-typical pathohistology in the enteric nervous system (ENS). Both, clinical symptoms and pathohistological changes in the ENS occur at early stages and can precede the motor manifestations of PD. Two recent studies reported an association between changes in gut microbiota composition and PD. We hypothesized that alterations in gut microbiota might be accompanied by altered concentrations of short chain fatty acids (SCFA), one main metabolic product of gut bacteria.

METHODS

We quantitatively analyzed SCFA concentrations (using gas chromatography) and microbiota composition (using quantitative PCR) in fecal samples of 34 PD patients and 34 age-matched controls.

RESULTS

Fecal SCFA concentrations were significantly reduced in PD patients compared to controls. The bacterial phylum Bacteroidetes and the bacterial family Prevotellaceae were reduced, Enterobacteriaceae were more abundant in fecal samples from PD patients compared to matched controls.

CONCLUSIONS

Our study confirms the recently reported association between PD and the abundance of certain gut microbiota and shows a reduction in fecal SCFA concentrations (one main metabolic product of certain gut bacteria). The reduction in SCFA might, theoretically, induce alterations in the ENS and contribute to gastrointestinal dysmotility in PD. Prospective longitudinal studies in subjects at risk for PD are required to further elucidate the causal role of gut microbiota and microbial products in the development of PD and PD-associated dysmotility.

Gut dysfunction in Parkinson's disease

Early involvement of gut is observed in Parkinson’s disease (PD) and symptoms such as constipation may precede motor symptoms. α-Synuclein pathology is extensively evident in the gut and appears to follow a rostrocaudal gradient. The gut may act as the starting point of PD pathology with spread toward the central nervous system. This spread of the synuclein pathology raises the possibility of prion-like propagation in PD pathogenesis. Recently, the role of gut microbiota in PD pathogenesis has received attention and some phenotypic correlation has also been shown. The extensive involvement of the gut in PD even in its early stages has led to the evaluation of enteric α-synuclein as a possible biomarker of early PD. The clinical manifestations of gastrointestinal dysfunction in PD include malnutrition, oral and dental disorders, sialorrhea, dysphagia, gastroparesis, constipation, and defecatory dysfunction. These conditions are quite distressing for the patients and require relevant investigations and adequate management. Treatment usually involves both pharmacological and non-pharmacological measures. One important aspect of gut dysfunction is its contribution to the clinical fluctuations in PD. Dysphagia and gastroparesis lead to inadequate absorption of oral anti-PD medications. These lead to response fluctuations, particularly delayed-on and no-on, and there is significant relationship between levodopa pharmacokinetics and gastric emptying in patients with PD. Therefore, in such cases, alternative routes of administration or drug delivery systems may be required.

The effect of subthalamic deep brain stimulation on gastric motility in Parkinson's disease

OBJECTIVE

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is well established for treating the motor symptoms for advanced Parkinson's disease (PD) but its effects on gastric myoelectrical activity and gastrointestinal symptoms have not been well studied. The aim of this study was to evaluate the effect of STN-DBS on gastric motility using electrogastrography (EGG).

METHODS

Twenty patients with PD (5 females, 15 males; mean aged 58.0 ± 9.0 years) who underwent STN-DBS were studied. EGG was performed in fasting and postprandial conditions before STN-DBS and 3 months after the surgery. We also evaluated the frequency and severity of gastrointestinal symptoms based on a structured gastrointestinal dysfunction questionnaire.

RESULTS

After STN-DBS the percentage of normogastria (47.8 ± 20.7 vs 51.3 ± 15.1) and period dominant power (PDP) (11.8 ± 1.2 vs 12.3 ± 0.9) significantly increased, the percentage of arrhythmia decreased compared to the baseline during fasting and postprandial state. Abnormal response to a meal (power ratio of PDP <1 after meal) decreased from 70% to 55% after 3 months follow-up. The abnormal EGG (the percentage of normogastria <70%) decreased in both fasting (from 80% to 65% patients) and postprandial state (from 80% to 60% patients), respectively after the surgery. The most common GI symptoms reported prior to the surgery were constipation 95%, difficulty with defecation 85% and dysphagia 50%. After STN-DBS all gastrointestinal symptoms improved, the greatest improvement was observed in difficulty with defecation.

CONCLUSION

Our results suggest that STN-DBS improves gastric motility as well as gastrointestinal symptoms in PD. Further studies of gastrointestinal motility in PD are warranted.

[A role of the gastrointestinal tract microbiota in the pathogenesis of Parkinson's disease]

Microbiota is a community of microorganisms, viruses, protozoa, colonizing the gut. There are tight phylogenetic relationships between the gut microbiota and the human body, the disturbance of which may lead to the CNS dysfunction as well as to the development of neurodegenerative diseases. This review focuses on general and specific aspects of the influence of gut microbiota on the pathogenesis of Parkinson's disease (PD). Current theories and models of the relationship between microbiota and brain structures in PD are presented with a specific focus on neurochemical and immunological aspects of the problem.

Other forms of gastroparesis: postsurgical, Parkinson, other neurologic diseases, connective tissue disorders

Although many surgical procedures originally associated with gastroparesis are less commonly performed nowadays, several more recently developed upper abdominal procedures may be complicated by the development of gastroparesis. Gastroparesis has been described in association with neurologic disorders ranging from Parkinson disease to muscular dystrophy, and its presence may have important implications for patient management and prognosis. Although scleroderma is most frequently linked with gastrointestinal motility disorder, gastroparesis has been linked to several other connective tissue disorders. The management of these patients presents several challenges, and is best conducted in the context of a dedicated and skilled multidisciplinary team.

Causes and consequences of degeneration of the dorsal motor nucleus of the vagus nerve in Parkinson's disease

SIGNIFICANCE

Parkinson's disease (PD) is no longer considered merely a movement disorder caused by degeneration of dopamine neurons in the midbrain. It is now recognized as a widespread neuropathological syndrome accompanied by a variety of motor and nonmotor clinical symptoms. As such, any hypothesis concerning PD pathogenesis and pathophysiology must account for the entire spectrum of disease and not solely focus on the dopamine system.

RECENT ADVANCES

Based on its anatomy and the intrinsic properties of its neurons, the dorsal motor nucleus of the vagus nerve (DMV) is uniquely vulnerable to damage from PD. Fibers in the vagus nerve course throughout the gastrointestinal (GI) tract to and from the brainstem forming a close link between the peripheral and central nervous systems and a point of proximal contact between the environment and areas where PD pathology is believed to start. In addition, DMV neurons are under high levels of oxidative stress due to their high level of α-synuclein expression, fragile axons, and specific neuronal physiology. Moreover, several consequences of DMV damage, namely, GI dysfunction and unrestrained inflammation, may propagate a vicious cycle of injury affecting vulnerable brain regions.

CRITICAL ISSUES

Current evidence to suggest the vagal system plays a pivotal role in PD pathogenesis is circumstantial, but given the current state of the field, the time is ripe to obtain direct experimental evidence to better delineate it.

FUTURE DIRECTIONS

Better understanding of the DMV and vagus nerve may provide insight into PD pathogenesis and a neural highway with direct brain access that could be harnessed for novel therapeutic interventions.

The role of the vagal pathway and gastric dopamine in the gastroparesis of rats after a 6-hydroxydopamine microinjection in the substantia nigra

AIM

Gastroparesis is a common non-motor system symptom of Parkinson's disease (PD). However, the mechanism responsible for the gastric motor abnormality is not clear. We previously reported on the impaired gastric motility in 6-hydroxydopamine (6-OHDA) rats, which were treated with a bilateral microinjection of 6-OHDA in the substantia nigra (SN). We hypothesize that the enhanced dopamine system and reduced acetylcholine (Ach) in gastric tissues might contribute to the delayed gastric emptying observed in PD.

METHODS

A strain gauge force transducer, digital X-ray imaging system, Western blot, immunofluorescence and Radio Immunoassay were used in this study.

RESULTS

Dopaminergic neurones in the SN were greatly reduced following the bilateral microinjection of 6-OHDA. 6-OHDA rats exhibited impaired gastric motility and delayed gastric emptying, accompanied by increased dopamine content and the overexpression of D2 receptors in the stomach. The administration of the D2 receptor antagonist domperidone relieved gastric dysmotility in 6-OHDA rats, but the D1 receptor antagonist SCH23390 failed to do so. Subdiaphragmatic vagotomy prevented the increase in the gastric dopamine content and D2 receptor expression and improved gastric dysmotility in 6-OHDA rats.

CONCLUSION

Dopaminergic deficiency in the SN results in impaired gastric motility, possibly as a result of the enhanced activity of dopamine system and reduced Ach in gastric tissue. The vagus nerve plays an important role in peripheral gastric motility disorder.

Delayed gastric emptying in Parkinson's disease

Gastrointestinal symptoms are evident in all stages of Parkinson's disease (PD). Most of the gastrointestinal abnormalities associated with PD are attributable to impaired motility. At the level of the stomach, this results in delayed gastric emptying. The etiology of delayed gastric emptying in PD is probably multifactorial but is at least partly related to Lewy pathology in the enteric nervous system and discrete brainstem nuclei. Delayed gastric emptying occurs in both early and advanced PD but is underdetected in routine clinical practice. Recognition of delayed gastric emptying is important because it can cause an array of upper gastrointestinal symptoms, but additionally it has important implications for the absorption and action of levodopa. Delayed gastric emptying contributes significantly to response fluctuations seen in people on long-term l-dopa therapy. Neurohormonal aspects of the brain-gut axis are pertinent to discussions regarding the pathophysiology of delayed gastric emptying in PD and are also hypothesized to contribute to the pathogenesis of PD itself. Ghrelin is a gastric-derived hormone with potential as a therapeutic agent for delayed gastric emptying and also as a novel neuroprotective agent in PD. Recent findings relating to ghrelin in the context of PD and gastric emptying are considered. This article highlights the pathological abnormalities that may account for delayed gastric emptying in PD. It also considers the wider relevance of abnormal gastric pathology to our current understanding of the etiology of PD.

Parkinson's disease is not associated with gastrointestinal myenteric ganglion neuron loss

Gastrointestinal dysfunction is a prominent non-motor feature of Parkinson's disease (PD) that contributes directly to the morbidity of patients, complicates management of motor symptoms, and may herald incipient PD in patients without motor disability. Although PD has traditionally been considered a disease of dopaminergic neurons in the substantia nigra, analyses of gastrointestinal samples from PD patients have consistently revealed pathology in the enteric nervous system. The relationship of PD pathology to GI dysmotility is poorly understood, and this lack of understanding has led to limited success in developing treatments for PD-related GI symptoms. We have quantitatively compared myenteric neuron density and relative abundance of NO, VIP, and catecholamine neurons between patients with PD and control individuals along the length of the GI tract. In addition, we have examined the frequency of GI α-synuclein neuritic pathology and its co-localization with the same neuronal markers. We have included a comparison with a small population of patients with incidental Lewy bodies found at autopsy. These data indicate that there is no neuronal loss in the myenteric plexus in PD. Lewy body pathology parallels parasympathetic autonomic input from the dorsal motor nucleus of the vagus, not the distribution of extrinsic sympathetic input or intrinsic enteric neurons, and is only rarely co-localized with tyrosine hydroxylase. These data provide a critical background to which further analyses of the effect of PD on the GI tract may be compared and suggest that neuropathology in myenteric neurons is unlikely to be a causative factor in PD-related GI dysmotility.

Subthalamic deep brain stimulation can improve gastric emptying in Parkinson's disease

It is established that deep brain stimulation of the subthalamic nucleus improves motor function in advanced Parkinson's disease, but its effects on autonomic function remain to be elucidated. The present study was undertaken to investigate the effects of subthalamic deep brain stimulation on gastric emptying. A total of 16 patients with Parkinson's disease who underwent bilateral subthalamic deep brain stimulation were enrolled. Gastric emptying was expressed as the peak time of (13)CO(2) excretion (T(max)) in the (13)C-acetate breath test and was assessed in patients with and without administration of 100-150 mg levodopa/decarboxylase inhibitor before surgery, and with and without subthalamic deep brain stimulation at 3 months post-surgery. The pattern of (13)CO(2) excretion curve was analysed. To evaluate potential factors related to the effect of subthalamic deep brain stimulation on gastric emptying, we also examined the association between gastric emptying, clinical characteristics, the equivalent dose of levodopa and serum ghrelin levels. The peak time of (13)CO(2) excretion (T(max)) values for gastric emptying in patients without and with levodopa/decarboxylase inhibitor treatment were 45.6 ± 22.7 min and 42.5 ± 13.6 min, respectively (P = not significant), thus demonstrating levodopa resistance. The peak time of (13)CO(2) excretion (T(max)) values without and with subthalamic deep brain stimulation after surgery were 44.0 ± 17.5 min and 30.0 ± 12.5 min (P < 0.001), respectively, which showed that subthalamic deep brain stimulation was effective. Simultaneously, the pattern of the (13)CO(2) excretion curve was also significantly improved relative to surgery with no stimulation (P = 0.002), although the difference with and without levodopa/decarboxylase inhibitor was not significant. The difference in peak time of (13)CO(2) excretion (T(max)) values without levodopa/decarboxylase inhibitor before surgery and without levodopa/decarboxylase inhibitor and subthalamic deep brain stimulation after surgery was not significant, although motor dysfunction improved and the levodopa equivalent dose decreased after surgery. There was little association between changes in ghrelin levels (Δghrelin) and changes in T(max) values (ΔT(max)) in the subthalamic deep brain stimulation trial after surgery (r = -0.20), and no association between changes in other characteristics and ΔT(max) post-surgery in the subthalamic deep brain stimulation trial. These results showed that levodopa/decarboxylase inhibitor did not influence gastric emptying and that subthalamic deep brain stimulation can improve the dysfunction in patients with Parkinson's disease possibly by altering the neural system that controls gastrointestinal function after subthalamic deep brain stimulation. This is the first report to show the effectiveness of subthalamic deep brain stimulation on gastrointestinal dysfunction as a non-motor symptom in Parkinson's disease.

Gastroparesis and Parkinson's disease: a systematic review

Some of the gastrointestinal (GI) symptoms commonly experienced by patients with Parkinson's disease (PD) have been attributed to gastroparesis; however, the precise prevalence and relevance of gastric emptying delay in PD is unclear. The definition of gastroparesis varies; currently the most widely accepted definition (from the National Institute of Diabetes and Digestive and Kidney Diseases Gastroparesis Clinical Research Consortium) is the presence of appropriate symptoms (including nausea, retching, vomiting, stomach fullness, and inability to finish a meal) for ≥ 12 weeks, together with delayed gastric emptying on scintigraphy and the absence of any obstructive lesions on upper GI endoscopy. In PD patients, gastroparesis has the potential to affect nutrition and quality of life, as well as the absorption of PD medications, including L-dopa. This reduced absorption of L-dopa has implications for the control of the PD motor symptoms for which it is administered. We performed a systematic review of the literature on gastroparesis in PD with the aim of developing an evidence-based approach to its management. Based on this review, we conclude that while gastric emptying has been reported to be frequently delayed in PD, the existing data do not permit definitive conclusions concerning its true prevalence, relationship to the underlying disease process, relevance to PD management, or the optimal therapy of related GI symptoms. Further study of these important issues is, therefore, required.

Motility disorders in the patient with neurologic disease

Gastrointestinal symptoms are common in the patient with chronic neurologic disease and may loom large in terms of impact on quality of life and on nutrition and mobility. A knowledge of the range of gastrointestinal disorders associated with a given neurologic disease, together with an understanding of the risks and benefits of various therapeutic options and approaches, should aid gastroenterologists in their efforts to contribute to the care of these patients. In most instances a multidisciplinary team (neurologist/neurosurgeon, gastroenterologist, nutritionist, therapist, specialist nurse) aware of the wishes and needs of the family and their carers and mindful of the nature and the natural history of the underlying disease process are best placed to assess and manage these problems.

No evidence of impaired gastric emptying in early Huntington's Disease

Background: Several factors, such as dysphagia, an increased motor activity, increased metabolic rate and a hypermetabolic state have been discussed as contributing to weight loss even at the early stages of Huntington’s Disease (HD). Aim of this pilot study was to investigate gastric emptying as a possible reason for weight loss in HD.

Methods: 11 HD participants at early stages of the disease and matched controls were investigated by using the well-established and non-invasive 13C-octanoate breath test. The “Gastroparesis Cardinal Symptom Index” and the “Short-Form Leeds Dyspepsia Questionnaire” were used for clinical evaluation of gastroparesis or dyspepsia.

Results: When compared to standard values ​​given in literature and controls all HD patients had normal breath test results. There was no evidence of gastroparesis or dyspepsia. There was a correlation of breath test results with the cognitive and functional performance of HD participants.

Conclusion: According to our data, there is no evidence of impaired gastric emptying in early HD. We can not exclude that gastric emptying contributes to weight loss at more advanced stages of the disease.