Enteric cholinergic neuropathy in patients with diabetes: Non-invasive assessment with positron emission tomography

Diabetic gastroenteropathy: Associations between gastrointestinal symptoms, motility, and extraintestinal autonomic measures

BACKGROUND

Diabetic gastroenteropathy can cause significant diagnostic challenges. Still, it remains unknown if measures of extraintestinal autonomic function reflect diabetic gastroenteropathy. We aimed to assess the associations between (1) gastrointestinal symptoms and motility measures and (2) gastrointestinal symptoms/motility measures and extraintestinal autonomic markers.

METHODS

We included 81 persons with type 1 or type 2 diabetes (65% female, mean age 54) with gastrointestinal symptoms and autonomic neuropathy. The Gastroparesis Cardinal Symptom Index (GCSI) and the Gastrointestinal Symptom Rating Scale (GSRS) assessed gastrointestinal symptoms. The wireless motility capsule (Smartpill™) assessed panenteric transit times and motility indices. Cardiovascular reflex tests (VAGUS™) and cardiac vagal tone (eMotion Faros) estimated cardiovascular autonomic neuropathy, while the SUDOSCAN™ evaluated sudomotor function.

KEY RESULTS

Proximal gastrointestinal symptoms were positively associated with the gastric motility index (GCSI: 1.18 (1.04-1.35), p = 0.01; GSRS: 1.15 (1.03-1.29), p = 0.02; median ratio (95% CI)), while only satiety correlated with gastric emptying time (1.24 (1.03-1.49), p = 0.02). Diarrhea was associated with decreased small bowel transit time (0.93 (0.89-0.98), p = 0.005), while constipation were associated with prolonged colonic transit time (1.16 (1.03-1.31), p = 0.02). Gastrointestinal symptoms increased with the degree of abnormal cardiovascular reflex tests (GCSI: 0.67 (0.16-1.19), p = 0.03; GSRS: 0.87 (0.30-1.45), p = 0.01; mean difference (95% CI)) but not with motility measures. Cardiac vagal tone and sudomotor function were not associated with gastrointestinal markers.

CONCLUSIONS & INFERENCES

Gastrointestinal and extraintestinal autonomic measures were not associated. However, proximal gastrointestinal symptoms were associated with the gastric motility index and cardiovascular reflex tests. Hence, the latter may contribute to evaluating whether proximal gastrointestinal symptoms are autonomically derived.

MRI-Based Quantification of Pan-Alimentary Function and Motility in Subjects with Diabetes and Gastrointestinal Symptoms

Background: Diabetes-induced gastrointestinal (GI) symptoms are common but difficult to correctly diagnose and manage. We used multi-segmental magnetic resonance imaging (MRI) to evaluate structural and functional GI parameters in diabetic patients and to study the association with their symptomatic presentation. Methods: Eighty-six participants (46 with diabetes and GI symptoms, 40 healthy controls) underwent baseline and post-meal MRI scans at multiple timepoints. Questionnaires were collected at inclusion and following the scans. Data were collected from the stomach, small bowel, and colon. Associations between symptoms and collected data were explored. Utilizing machine learning, we determined which features differentiated the two groups the most. Key Results: The patient group reported more symptoms at inclusion and during MRI scans. They showed 34% higher stomach volume at baseline, 40% larger small bowel volume, 30% smaller colon volume, and less small bowel motility postprandially. They also showed positive associations between gastric volume and satiety scores, gastric emptying time and reflux scores, and small bowel motility and constipation scores. No differences in gastric emptying were observed. Small bowel volume and motility were used as inputs to a classification tool that separated patients and controls with 76% accuracy. Conclusions: In this work, we studied structural and functional differences between patients with diabetes and GI symptoms and healthy controls and observed differences in stomach, small bowel, and colon volumes, as well as an adynamic small bowel in patients with diabetes and GI symptoms. Associations between recorded parameters and perceived symptoms were also explored and discussed.

Onset and mortality of Parkinson's disease in relation to type II diabetes

OBJECTIVES

There is growing evidence that Parkinson's disease and diabetes are partially related diseases; however, the association between the two, and the impact of specific treatments, are still unclear. We evaluated the effect of T2D and antidiabetic treatment on age at PD onset and on all-cause mortality.

RESEARCH DESIGN AND METHODS

The standardized rate of T2D was calculated for PD patients using the direct method and compared with subjects with essential tremor (ET) and the general Italian population. Age at onset and survival were also compared between patients without T2D (PD-noT2D), patients who developed T2D before PD onset (PD-preT2D) and patients who developed T2D after PD onset (PD-postT2D).

RESULTS

We designed a retrospective and prospective study. The T2D standardized ratio of PD (N = 8380) and ET (N = 1032) patients was 3.8% and 6.1%, respectively, while in the Italian general population, the overall prevalence was 5.3%. In PD-preT2D patients, on antidiabetic treatment, the onset of PD was associated with a + 6.2 year delay (p < 0.001) while no difference was observed in PD-postT2D. Occurrence of T2D before PD onset negatively affected prognosis (adjusted hazard ratio = 1.64 [95% CI 1.33-2.02]; p < 0.001), while no effect on survival was found in PD-postT2D subjects (hazard ratio = 0.86, [95% CI 0.53-1.39]; p = 0.54).

CONCLUSIONS

T2D, treated with any antidiabetic therapy before PD, is associated with a delay in its onset. Duration of diabetes increases mortality in PD-preT2D, but not in PD-postT2D. These findings prompt further studies on antidiabetic drugs as a potential disease-modifying therapy for PD.

Gastric Emptying Time and Volume of the Small Intestine as Objective Markers in Patients With Symptoms of Diabetic Enteropathy

Background/Aims

Patients with diabetes mellitus (DM) often suffer from gastrointestinal (GI) symptoms, but these correlate poorly to established objective GI motility measures. Our aim is to perform a detailed evaluation of potential measures of gastric and small intestinal motility in patients with DM type 1 and severe GI symptoms.

Methods

Twenty patients with DM and 20 healthy controls (HCs) were included. GI motility was examined with a 3-dimensional-Transit capsule, while organ volumes were determined by CT scans.

Results

Patients with DM and HCs did not differ with regard to median gastric contraction frequency (DM 3.0 contractions/minute [interquartile range {IQR}, 2.9-3.0]; HCs 2.9 [IQR, 2.8-3.1]; P = 0.725), amplitude of gastric contractions (DM 9 mm [IQR, 8-11]; HCs 11 mm (IQR, 9-12); P = 0.151) or fasting volume of the stomach wall (DM 149 cm3 [IQR, 112-187]; HCs 132 cm3 [IQR, 107-154]; P = 0.121). Median gastric emptying time was prolonged in patients (DM 3.3 hours [IQR, 2.6-4.6]; HCs 2.4 hours [IQR, 1.8-2.7]; P = 0.002). No difference was found in small intestinal transit time (DM 5 hours [IQR, 3.7-5.6]; HCs 4.8 hours [IQR, 3.9-6.0]; P = 0.883). However, patients with DM had significantly larger volume of the small intestinal wall (DM 623 cm3 [IQR, 487-766]; HCs 478 cm3 [IQR, 393-589]; P = 0.003). Among patients, 13 (68%) had small intestinal wall volume and 9 (50%) had gastric emptying time above the upper 95% percentile of HCs.

Conclusion

In our study, gastric emptying time and volume of the small intestinal wall appeared to be the best objective measures in patients with DM type 1 and symptoms and gastroenteropathy.

Assessment of Gastrointestinal Autonomic Dysfunction: Present and Future Perspectives

The autonomic nervous system delicately regulates the function of several target organs, including the gastrointestinal tract. Thus, nerve lesions or other nerve pathologies may cause autonomic dysfunction (AD). Some of the most common causes of AD are diabetes mellitus and α-synucleinopathies such as Parkinson’s disease. Widespread dysmotility throughout the gastrointestinal tract is a common finding in AD, but no commercially available method exists for direct verification of enteric dysfunction. Thus, assessing segmental enteric physiological function is recommended to aid diagnostics and guide treatment. Several established assessment methods exist, but disadvantages such as lack of standardization, exposure to radiation, advanced data interpretation, or high cost, limit their utility. Emerging methods, including high-resolution colonic manometry, 3D-transit, advanced imaging methods, analysis of gut biopsies, and microbiota, may all assist in the evaluation of gastroenteropathy related to AD. This review provides an overview of established and emerging assessment methods of physiological function within the gut and assessment methods of autonomic neuropathy outside the gut, especially in regards to clinical performance, strengths, and limitations for each method.