Mechanical and electrical activity in the duodenum of diabetics with and without diarrhea. Pressures, differential pressures and action potentials

DIgestive COmplications in DIabetes - the DICODI population study

BACKGROUND

Diabetes type 1 and type 2 may develop gastrointestinal complications e.g., gastroparesis and gastroenteropathy. Concomitant celiac disease and pancreatic exocrine insufficiency occur with high prevalence in diabetes and with symptomatic overlap. Consequently, it is a challenge to disentangle symptoms of these conditions and separate them from functional dyspepsia. We aim to develop a clinical decision-support tool to differentiate the underlying disease in a plethora of gastrointestinal symptoms.

METHODS

An internet-based computerized survey will collect basic characteristics (diabetes type, age, gender, duration, HbA1c, treatment) and patient reported outcomes by validated questionnaires focusing on (1) gastroparesis using Gastroparesis Cardinal Symptom Index; (2) gastroenteropathy using Gastrointestinal Symptom Rating Scale; (3) celiac disease using Celiac Symptom Index and (4) pancreatic exocrine insufficiency with Pancreatic Exocrine Insufficiency Questionnaire. Logistic regression and multiple regression analyses will identify risk factors and gastrointestinal complications. Cluster analyses and machine learning will classify different symptoms and co-existing presentations, into a likely diagnosis. We seek biomarkers for autonomic neuropathy by characterizing development of retinopathy using the Visual Function Questionnaire-25 and peripheral neuropathy by the Michigan neuropathy questionnaire. Participants are re-examined yearly for disease progression over time.

RESULTS

From focus group studies gastrointestinal symptoms are of major concern in diabetes. Potentially, estimates of symptom prevalence, risk factor identification and classifications of gastrointestinal complications can be unraveled for feedback to health care providers.

CONCLUSION

The web-based DICODI project will open up possibilities to detect gastrointestinal complications of diabetes in a societal setting, benefitting people living with diabetes, health care professionals, and society.

Delayed stomach to caecum transit time in the diabetic rat. Possible role of hyperglucagonaemia

Disturbances of gastrointestinal motility are a common feature of diabetes mellitus and are usually ascribed to autonomic neuropathy. In order to assess the role of other factors on changes in motility in diabetes we have studied the stomach to caecum transit time (SCTT) during the progression of streptozotocin induced diabetes in the rat. Rats were used one, two, four, and eight weeks after a single injection of streptozotocin and age matched animals were used as controls. In further experiments non-diabetic rats received a bolus injection of pancreatic glucagon (50 or 75 micrograms intraperitoneally) or its diluent. SCTT was estimated using the non-invasive hydrogen excretion method. SCTT was unaffected by the age of the animal (mean (SEM) value: 101 (5) min), but was significantly delayed at one week (139 (11) min, p less than 0.01), two weeks (163 (16) min, p less than 0.01), four weeks (148 (9) min, p less than 0.01), and eight weeks (171 (13) min, p less than 0.01) after streptozotocin. SCTT was also slower during hyperglucagonaemia (control 96 (6) min; glucagon treated 50 micrograms: 120 (7) min, p less than 0.05 and 75 micrograms: 127 (8), p less than 0.05). Since autonomic neuropathy is not a recognised feature of the initial stages of diabetes hyperglucagonaemia may be responsible, at least in part, for diabetes induced changes in gastrointestinal motility.

Abnormalities of the migrating motor complex in diabetics with autonomic neuropathy and diarrhea

Diarrhea is a common symptom in long-standing diabetes. The pathogenesis of this diarrhea remains obscure, although it appears to be related to the development of autonomic neuropathy, which may cause several abnormalities including altered gut motility. We studied fasting gastrointestinal motility for a mean of 210 min in a group of 12 type-II diabetics with diarrhea. All patients had peripheral neuropathy and symptoms of autonomic neuropathy. Their motor activity was compared with that of a group of six normal volunteers. In addition, gastrointestinal transit time was assessed by the hydrogen breath test. The presence of bacterial overgrowth was assessed by the hydrogen breath test and culture of jejunal secretions. The diabetics showed grossly disordered motor activity. There was a complete absence of phase-III activity in two patients. Most phase III's commenced in the distal duodenum or jejunum. The phase-III component was often of short duration at each recording site. There was increased velocity of propagation between sites. Continuous phase-II activity was noted in some patients. Antral activity was absent or reduced during phase II. Gastrointestinal transit time was significantly prolonged in the diabetics. Bacterial overgrowth was demonstrated in three diabetic subjects. These motility abnormalities are nonspecific and are unlikely to play a major role in the pathogenesis of diabetic diarrhea.

Autonomic neuropathy: its diagnosis and prognosis

Autonomic neuropathy is now well established as a relatively common and significant complication of diabetes mellitus. Its importance has been clarified in recent years during which the extent of autonomic control over all areas of body function has been defined. Using simple cardiovascular reflex tests, autonomic abnormalities can be demonstrated without any corresponding symptoms. The often stated concept of 'patchy' involvement in diabetic autonomic neuropathy should now be rejected as too should the view that autonomic neuropathy is either 'present' or 'absent' based on a single test result. When generalized and predominantly metabolic disturbances, as in diabetes, give rise to impaired nerve function, autonomic as well as somatic components of the nerve are affected. Where damage is severe this leads to the characteristic florid picture of symptomatic autonomic neuropathy with its particularly poor prognosis. For the physician in a busy clinic, much of the theoretical and experimental basis for autonomic neuropathy may not appear of direct relevance. However, he has now to be aware of the clinical implications of autonomic damage in the diabetic. This may have particular relevance in the care of the diabetic foot (see Chapter 10), the recognition of many of the vague symptoms associated with autonomic damage, the treatment of disabling features such as postural dizziness and nocturnal diarrhoea, and an awareness of the poor prognosis associated with symptomatic autonomic neuropathy. He will also need to be alert to the dangers of general anaesthesia in such patients, and the possibility of sudden unexpected deaths. Diabetic autonomic neuropathy causes widespread abnormalities, some of which are clinically apparent, some of which can be detected by sensitive tests, and others which have yet to be discovered. Inclusion of the neuropeptides and other hormones within the compass of autonomic control has opened up a whole new area of investigative interest, with many complex interrelationships which still need to be unravelled. This should lead to better understanding of the pathophysiological processes that cause damage to diabetic nerves. With so much research effort directed towards better glycaemic control and aldose reductase inhibitors (see Chapter 8), it may eventually be possible to reverse or prevent this potentially disabling and lethal complication of diabetes.

Evidence for abnormal cholinergic neuromuscular transmission in diabetic rat small intestine

Proximal and distal rat small intestine from control, diabetic, and insulin-treated diabetic rats was cut into strips measuring 6.0 X 10.0 mm. Strips cut along the oral-caudal axis were called longitudinal strips, while those cut 90 degrees to that axis were called circular strips. The strips were stretched to their optimum lengths and subjected to electrical field stimulation (0.1-1.0-ms pulse duration, 30-270 mA, 1-26 Hz) in the presence of Krebs' solution and Krebs' solution plus 10(-6) M atropine. Field stimulation produced atropine-sensitive and atropine-resistant contractions in all strips. Significant differences among the three groups were found in the amplitudes of atropine-sensitive contractions in strips from distal longitudinal muscle. Controls showed the highest amplitude contractions and diabetics the lowest, whereas the insulin-treated diabetics showed contractions intermediate in amplitude. No significant differences were noted among the atropine-resistant contractions. Field stimulation delivered at pulse durations of 5.0 and 50.0 ms in the presence of neural blockade with tetrodotoxin (5 X 10(-6) M) produced similar contraction amplitudes among the three groups. These results suggest that streptozotocin-induced diabetes mellitus is associated with defective cholinergic neuromuscular transmission in the myenteric plexus of the distal small intestine. Insulin therapy seems to improve the abnormality.