Relation of symptoms to impaired stomach, small bowel, and colon motility in long-standing diabetes

Gastrointestinal transit and contractility in diabetic constipation: A wireless motility capsule study on diabetes patients and healthy controls

BACKGROUND

Diabetic constipation is traditionally attributed to slow colonic transit, despite limited evidence. More than half of patients find treatment unsatisfactory. To improve treatment, there is a need for better diagnostic understanding of the condition.

OBJECTIVE

In this wireless motility capsule study, we aimed to investigate gastrointestinal transit and contractility in diabetes patients with and without constipation, and in healthy controls.

METHODS

We prospectively included type 1 or type 2 diabetes patients with gastrointestinal symptoms. Based on the Gastrointestinal Symptom Rating Scale we distinguished into two groups: with constipation and without constipation. Non-diabetic controls were asymptomatic. All were examined with wireless motility capsule, determining transit times and contractility parameters.

RESULTS

57 patients (42 women, 46 with type 1 diabetes) and 26 healthy controls (14 women) were included. We found no difference in transit times between diabetes patients with and without constipation. Compared to healthy controls (35:55, h:min), whole-gut transit was slower in both diabetes patients with constipation (66:15, p = 0.03) and without constipation (71:16, p < 0.001). Small bowel motility index correlated rs  = -0.32 (p = 0.01) with constipation symptoms.

CONCLUSIONS

Diabetes patients with constipation had similar transit times as those without constipation. Both groups had slower whole-gut transit than healthy controls. Constipation was associated with reduced small bowel, but not colonic contractility. Our results imply that other mechanisms than slow colonic transit may be more important in the pathogenesis of diabetic constipation.

Classification of gastric emptying and orocaecal transit through artificial neural networks

Classical quantification of gastric emptying (GE) and orocaecal transit (OCT) based on half-life time T$ _{50} $, mean gastric emptying time (MGET), orocaecal transit time (OCTT) or mean caecum arrival time (MCAT) can lead to misconceptions when analyzing irregularly or noisy data. We show that this is the case for gastrointestinal transit of control and of diabetic rats. Addressing this limitation, we present an artificial neural network (ANN) as an alternative tool capable of discriminating between control and diabetic rats through GE and OCT analysis. Our data were obtained via biological experiments using the alternate current biosusceptometry (ACB) method. The GE results are quantified by T$ _{50} $ and MGET, while the OCT is quantified by OCTT and MCAT. Other than these classical metrics, we employ a supervised training to classify between control and diabetes groups, accessing sensitivity, specificity, $ f_1 $ score, and AUROC from the ANN. For GE, the ANN sensitivity is 88%, its specificity is 83%, and its $ f_1 $ score is 88%. For OCT, the ANN sensitivity is 100%, its specificity is 75%, and its $ f_1 $ score is 85%. The area under the receiver operator curve (AUROC) from both GE and OCT data is about 0.9 in both training and validation, while the AUCs for classical metrics are 0.8 or less. These results show that the supervised training and the binary classification of the ANN was successful. Classical metrics based on statistical moments and ROC curve analyses led to contradictions, but our ANN performs as a reliable tool to evaluate the complete profile of the curves, leading to a classification of similar curves that are barely distinguished using statistical moments or ROC curves. The reported ANN provides an alert that the use of classical metrics can lead to physiological misunderstandings in gastrointestinal transit processes. This ANN capability of discriminating diseases in GE and OCT processes can be further explored and tested in other applications.

Association Between Gastric Emptying Time and Incidence of Cardiovascular Diseases in Subjects With Diabetes

Background/Aims

Delayed gastric emptying (GE) is associated with high morbidity and mortality in subjects with diabetes. The aim of this study is to investigate associations between GE time and the major cardiovascular events (coronary heart diseases and ischemic stroke) in diabetic subjects with upper gastrointestinal (UGI) symptoms.

Methods

Among 259 subjects with chronic UGI symptoms who underwent gastric emptying study (GES) over 13 years, 122 diabetic subjects without gastric surgery and/or rapid GE were enrolled in this study. We also gathered data about baseline demographics, clinical characteristics, estimated GE half-time (GE T_½) and incidence of cardiovascular events following GES.

Results

The mean age of subjects was 64.0 ± 17.4 years. There were 86 women and 104 subjects with type 2 diabetes. There were 52 (42.6%) subjects with normal GE, 50 (41.0.%) subjects with mild delayed GE, and 20 (16.4%) subjects with marked delayed GE. During follow-up (median, 207 weeks), cardiovascular events occurred in 7 (13.5%) subjects with normal GE, 4 (8.0%) subjects with mild delayed GE and 7 (35.0%) subjects with marked GE (P = 0.015). Univariate analysis showed that GE T_½ was significantly associated with incidence of cardiovascular events (crude OR, 1.74; 95% CI, 1.12–2.69; P = 0.014). In a multivariate model, association between GE T_½ and incidence of cardiovascular events remained statistically significant after adjustment for baseline characteristics and comorbidities (adjusted OR, 1.94; 95% CI, 1.21–3.12; P = 0.006).

Conclusion

A delay of GE was associated with an increased incidence of cardiovascular events in diabetic subjects with chronic UGI symptoms.

Diabetes-induced mechanophysiological changes in the small intestine and colon

The disorders of gastrointestinal (GI) tract including intestine and colon are common in the patients with diabetes mellitus (DM). DM induced intestinal and colonic structural and biomechanical remodeling in animals and humans. The remodeling is closely related to motor-sensory abnormalities of the intestine and colon which are associated with the symptoms frequently encountered in patients with DM such as diarrhea and constipation. In this review, firstly we review DM-induced histomorphological and biomechanical remodeling of intestine and colon. Secondly we review motor-sensory dysfunction and how they relate to intestinal and colonic abnormalities. Finally the clinical consequences of DM-induced changes in the intestine and colon including diarrhea, constipation, gut microbiota change and colon cancer are discussed. The final goal is to increase the understanding of DM-induced changes in the gut and the subsequent clinical consequences in order to provide the clinicians with a better understanding of the GI disorders in diabetic patients and facilitates treatments tailored to these patients.

Tangshen Formula Attenuates Colonic Structure Remodeling in Type 2 Diabetic Rats

Aim. This study investigated the effect and mechanism of the Chinese herbal medicine Tangshen Formula (TSF) on GI structure remodeling in the rat model of diabetes. Methods. Type 2 diabetic rats were used. Wet weight per unit length, layer thicknesses, levels of collagens I and III, nuclear factor kappa B (NF-κB), interferon-γ (IFN-γ), interleukin-6 (IL-6), transforming growth factor-β1 (TGF-β1), and Smad2/3 expression in the rat colon were measured. Results. Compared with the control group animals, wet weight and layer thicknesses of the colon increased, and expressions of collagens I and III, NF-κB, IFN-γ, IL-6, TGF-β1, and Smad2/3 increased significantly in the diabetic animals. TSF inhibited increase in colonic wet weight and layer thicknesses, downregulated expressions of collagens I and III in the mucosal layer, and downregulated expressions of NF-κB, IFN-γ, IL-6, TGF-β1, and Smad2/3 in the colon wall. Furthermore, level of expression of NF-κB was associated with those of TGF-β1 and Smad2/3. Expression of TGF-β1 was associated with the most histomorphometric parameters including colonic weight, mucosal and muscle thicknesses, and levels of collagens I and III in mucosal layer. Conclusion. TSF appears to attenuate colonic structure remodeling in type 2 diabetic rats through inhibiting the overactivated pathway of NF-κB, thus reducing expressions of TGF-β1.

Blunting of Colon Contractions in Diabetics with Gastroparesis Quantified by Wireless Motility Capsule Methods

Generalized gut transit abnormalities are observed in some diabetics with gastroparesis. Relations of gastric emptying abnormalities to colon contractile dysfunction are poorly characterized. We measured colon transit and contractility using wireless motility capsules (WMC) in 41 healthy subjects, 12 diabetics with gastroparesis (defined by gastric retention >5 hours), and 8 diabetics with normal gastric emptying (≤5 hours). Overall numbers of colon contractions >25 mmHg were calculated in all subjects and were correlated with gastric emptying times for diabetics with gastroparesis. Colon transit periods were divided into quartiles by time and contraction numbers were calculated for each quartile to estimate regional colon contractility. Colon transit in diabetics with gastroparesis was prolonged vs. healthy subjects (P<0.0001). Overall numbers of colon contractions in gastroparetics were lower than controls (P = 0.02). Diabetics with normal emptying showed transit and contraction numbers similar to controls. Gastric emptying inversely correlated with overall contraction numbers in gastroparetics (r = -0.49). Numbers of contractions increased from the 1^st to 4^th colon transit quartile in controls and diabetics with normal emptying (P≤0.04), but not gastroparetics. Numbers of contractions in the 3^rd and 4^th quartiles were reduced in gastroparetics vs. healthy controls (P≤0.05) and in the 4^th quartile vs. diabetics with normal emptying (P = 0.02). Numbers of contractions were greatest in the final 15 minutes of transit, but were reduced in gastroparetics vs. healthy controls and diabetics with normal emptying (P≤0.005). On multivariate analyses, differences in numbers of contractions were not explained by demographic or clinical variables. In conclusion, diabetics with gastroparesis exhibit delayed colon transit associated with reductions in contractions that are prominently blunted in latter transit phases and which correlate with delayed gastric emptying, while diabetics with normal emptying show no significant colonic impairments. These findings emphasize diabetic gastroparesis may be part of a generalized dysmotility syndrome.

Physical inactivity, water intake and constipation as risk factors for colorectal cancer among adults in Jordan

BACKGROUND

Physical activity has been found to play a role in cancer prevention. The purpose of this matched case-control study was to investigate the association between physical activity levels, water intake, constipation and colorectal cancer (CRC).

MATERIALS AND METHODS

Two hundred and thirty-two patients diagnosed with CRC (125 male, 107 female) were enrolled in this case-control study. Cases were matched to 271 population controls (137 male, 134 female).

RESULTS

Drinking more than 4 cups of water daily decreased the risk of CRC by 33-42%; however, this effect was non-significant. Having constipation was found to be a significant risk factor for developing CRC with an OR=6.284 (95%CI=2.741-14.40). With reference to sedentary behavior, minimum activity (600-3000 Metabolic Equivalents Task (MET)) had 43% protection against CRC and the level of Health Enhancing Physical Activity OR was 0.58 (at 95%CI; 0.37-0.92). A significant negative association was found between CRC and physical activity levels expressed as both METs and MET-hours/week (p for trend=0.017 and 0.03, respectively). Among females, a significant trend of reduction in CRC by 62% was observed with increasing the level of physical activity expressed in MET (p for trend=0.04).

CONCLUSIONS

The risk of CRC may be reduced by adopting a healthy lifestyle and practicing physically activity regularly, especially among females. Consuming adequate amounts of water and healthy bowel motility could also reduce the risk of CRC.

Epidemiology and clinical pathophysiology of uric acid kidney stones

There is global diversity in the prevalence of uric acid (UA) nephrolithiasis. UA nephrolithiasis comprises 8-10 % of all kidney stones in the United States. However, its prevalence is higher in patients with type 2 diabetes mellitus and those with obesity. Three significant urinary abnormalities have been described as the main etiologic factors for the development of UA nephrolithiasis; low urinary pH, hyperuricosuria and low urinary volume. However, an unduly acidic urine below the ionization constant of uric acid (pKa < 5.5) increases the urinary content of undissociated uric acid and thereby uric acid precipitation. Previous studies have shown the two major pathogenic mechanisms for unduly urinary pH are increased net acid excretion (NAE) and reduced renal ammonium (NH4 (+)), with a combination resulting in overly acidic urine. The impaired ammonium excretion has been demonstrated in a steady state in 24-hour urine and also following an oral ammonium chloride (NH4Cl) challenge to amplify ammoniogenic defects in this population. Similar abnormalities have been disclosed in normal populations and also in T2DM populations without kidney stones. To date, the underlying mechanism of increased acid production, source and nature of putative organic acid anions have not been fully elucidated. One plausible mechanism is the production of organic acid by intestinal and aerobic metabolism. This may occur in obese, diabetic and uric acid stone formers due to the differences in gut microflora.

Increased risk of colorectal cancer in type 2 diabetes is independent of diet quality

BACKGROUND

Poor diet increases the risk of both colorectal cancer and type 2 diabetes. We investigated the role of diet in the association between diabetes and colorectal cancer.

METHODS

We analyzed data from 484,020 individuals, aged 50-71 years who participated in the prospective National Institutes of Health-AARP Diet and Health Study and were cancer free at baseline (1995-1996). History of diabetes was self-reported. Diet quality was measured with the Healthy Eating Index-2005 (HEI-2005), using a self-administered food-frequency questionnaire. Cox regression models were constructed to estimate the hazard ratios (HR) and 95% confidence intervals (CI) of first primary incident colorectal cancer, overall and by anatomical location.

RESULTS

During an average follow-up of 9.2 years, we identified 7,598 new cases of colorectal cancer. After controlling for non-dietary confounders, diabetes was associated with increased risk of colorectal cancer (HR 1.27, 95% CI: 1.18, 1.36). Further adjustment for diet quality did not attenuate this association. Diabetes was associated with a HR of 1.23 (95% CI: 1.07, 1.40) in individuals with good diet (quartile 4 of HEI-2005) and 1.58 (95% CI: 1.34, 1.86) in those with poor diet (quartile 1 of HEI-2005), compared to those with no diabetes and good diet. Moreover, diabetes was associated with a stronger risk of proximal than distal colon cancer (HR: 1.33 vs. HR: 1.20), while poor diet was associated with a weaker risk of proximal colon cancer (HR: 1.18 vs. HR: 1.46).

CONCLUSION

Diabetes and poor diet, independently and additively are associated with the increased risk of colorectal cancer.

Delayed small intestinal transit in patients with long-standing type 1 diabetes mellitus: investigation of the relationships with clinical features, gastric emptying, psychological distress, and nutritional parameters

BACKGROUND

Studies on small intestinal transit in type 1 diabetes mellitus have reported contradictory results. This study assessed the orocecal transit time (OCTT) in a group of patients with type 1 diabetes mellitus and its relationships with gastrointestinal symptoms, glycemic control, chronic complications of diabetes, anthropometric indices, gastric emptying, small intestinal bacterial overgrowth (SIBO), and psychological distress.

SUBJECTS AND METHODS

Twenty-eight patients with long-standing (>10 years) type 1 diabetes mellitus (22 women, six men; mean age, 39 ± 9 years) participated in the study. The lactulose hydrogen breath test was used to determine OCTT and the occurrence of SIBO. The presence of anxiety and depression was assessed by the Hospital Anxiety and Depression scale. Gastric emptying was measured by scintigraphy. Anthropometric indices included body mass index, percentage body fat, midarm circumference, and arm muscle area.

RESULTS

There was a statistically significant increase in OCTT values in diabetes patients (79 ± 41 min) in comparison with controls (54 ± 17 min) (P=0.01). Individual analysis showed that OCTT was above the upper limit (mean+2 SD) in 30.8% of patients. All anthropometric parameters were significantly decreased (P<0.05) in patients with prolonged OCTT in comparison with those with normal OCTT. In contrast, there was no statistically significant association between prolonged OCTT and gastrointestinal symptoms, peripheral neuropathy, diabetic retinopathy, glycated hemoglobin, delayed gastric emptying, SIBO, anxiety, or depression.

CONCLUSIONS

Small bowel transit may be delayed in about one-third of patients with long-standing type 1 diabetes mellitus. This abnormality seems to have a negative effect on nutritional status in these patients.

Effect of diabetes mellitus on pharmacokinetic and pharmacodynamic properties of drugs

The effects of diabetes mellitus on the pharmacokinetics and pharmacodynamics of drugs have been well described in experimental animal models; however, only minimal data exist for humans and the current knowledge regarding the effects of diabetes on these properties remains unclear. Nevertheless, it has been observed that the pharmacokinetics and pharmacodynamics of drugs are changed in subjects with diabetes. It has been reported that diabetes may affect the pharmacokinetics of various drugs by affecting (i) absorption, due to changes in subcutaneous adipose blood flow, muscle blood flow and gastric emptying; (ii) distribution, due to non-enzymatic glycation of albumin; (iii) biotransformation, due to regulation of enzymes/transporters involved in drug biotransformation; and (iv) excretion, due to nephropathy. Previously published data also suggest that diabetes-mediated changes in the pharmacokinetics of a particular drug cannot be translated to others. Although clinical studies exploring the effect of diabetes on pharmacodynamics are still very limited, there is evidence that disease-mediated effects are not limited only to pharmacokinetics but also alter pharmacodynamics. However, for many drugs it remains unclear whether these influences reflect diabetes-mediated changes in pharmacokinetics rather than pharmacodynamics. In addition, even though diabetes-mediated pharmacokinetics and pharmacodynamics might be anticipated, it is important to study the effect on each drug and not generalize from observed data. The available data indicate that there is a significant variability in drug response in diabetic subjects. The discrepancies between individual clinical studies as well as between ex vivo and clinical studies are probably due to (i) the restricted and focused population of subjects in clinical studies; (ii) failure to consider type, severity and duration of the disease; (iii) histopathological characteristics generally being missing; and (iv) other factors such as varying medication use, dietary protein intake, age, sex and obesity. The obesity epidemic in the developed world has also inadvertently influenced the directions of pharmacological research. This review attempts to map new information gained since Gwilt published his paper in Clinical Pharmacokinetics in 1991. Although a large body of research has been conducted and significant progress has been made, we still have to conclude that the available information regarding the effect of diabetes on pharmacokinetics and pharmacodynamics remains unclear and further clinical studies are required before we can understand the clinical significance of the effect. An understanding of diabetes-mediated changes as well as of the source of the variability should lead to the improvement of the medical management and clinical outcomes in patients with this widespread disease.

Risk of gastroparesis in subjects with type 1 and 2 diabetes in the general population

OBJECTIVES

In patients with diabetes mellitus (DM) and upper gastrointestinal symptoms, a diagnosis of diabetic gastroparesis is often considered, but population-based data on the epidemiology of diabetic gastroparesis are lacking. We aimed to estimate the frequency of and risk factors for gastroparesis among community subjects with DM.

METHODS

In this population-based, historical cohort study, the medical records linkage system of the Rochester Epidemiology Project was used to identify 227 Olmsted County, MN residents with type 1 DM in 1995, a random sample of 360 residents with type 2 DM, and an age- and sex-stratified random sample of 639 nondiabetic residents. Using defined diagnostic criteria, we estimated the subsequent risk of developing gastroparesis in each group through 2006. The risk in DM, compared with frequency-matched community controls, was assessed by Cox proportional hazards modeling.

RESULTS

The cumulative proportions developing gastroparesis over a 10-year time period were 5.2% in type 1 DM, 1.0% in type 2 DM, and 0.2% in controls. The age- and gender-adjusted hazard ratios (HRs) for gastroparesis (relative to controls) was 33 (95% confidence interval (CI): 4.0, 274) in type 1 DM and 7.5 (95% CI: 0.8, 68) in type 2 DM. The risk of gastroparesis in type 1 DM was significantly greater than in type 2 DM (HR: 4.4 (1.1, 17)). Heartburn (HR: 6.6 (1.7, 25)) at baseline was associated with diabetic gastroparesis in type 1 DM.

CONCLUSIONS

Gastroparesis is relatively uncommon in patients with DM, although an increased risk for gastroparesis was observed in type 1 DM.

Altered calcium signaling in colonic smooth muscle of type 1 diabetic mice

Seventy-six percent of diabetic patients develop gastrointestinal symptoms, such as constipation. However, the direct effects of diabetes on intestinal smooth muscle are poorly described. This study aimed to identify the role played by smooth muscle in mediating diabetes-induced colonic dysmotility. To induce type 1 diabetes, mice were injected intraperitoneally with low-dose streptozotocin once a day for 5 days. Animals developed hyperglycemia (>200 mg/dl) 1 wk after the last injection and were euthanized 7-8 wk after the last treatment. Computed tomography demonstrated decreased overall gastrointestinal motility in the diabetic mice. In vitro contractility of colonic smooth muscle rings from diabetic mice was also decreased. Fura-2 ratiometric Ca(2+) imaging showed attenuated Ca(2+) increases in response to KCl stimulation that were associated with decreased light chain phosphorylation in diabetic mice. The diabetic mice also exhibited elevated basal Ca(2+) levels, increased myosin phosphatase targeting subunit 1 expression, and significant changes in expression of Ca(2+) handling proteins, as determined by quantitative RT-PCR and Western blotting. Mice that were hyperglycemic for <1 wk also showed decreased colonic contractile responses that were associated with decreased Ca(2+) increases in response to KCl stimulation, although without an elevation in basal Ca(2+) levels or a significant change in the expression of Ca(2+) signaling molecules. These data demonstrate that type 1 diabetes is associated with decreased depolarization-induced Ca(2+) influx in colonic smooth muscle that leads to attenuated myosin light chain phosphorylation and impaired colonic contractility.

Morphological analysis of colon goblet cells and submucosa in type I diabetic rats submitted to physical training

Colon layers, especially the submucosa, as well as the secretion of goblet cells are extremely important for the functioning and transit of substances in this organ. However, the damages arising from type I diabetes and the effects of physical training, which plays crucial role in the treatment of this disease, are not yet known in these regions. To analyze the changes in colon submucosa and goblet cells of diabetic rats, as well as the effects of physical training, Wistar rats were divided into four groups: sedentary control, trained control, sedentary diabetic (SD), and trained diabetic (TD). The training protocol consisted of swimming for 60 min a day, 5 days per week, during 8 weeks. Colon samples were collected, processed, and evaluated by histochemical and ultrastructural techniques. Goblet and submucosa cells did not show alterations in shape, size, protein and carbohydrate content, in all treatment groups. Decreased amount of collagen fibers, however, was observed in the submucosa and lamina propria of SD rats, but this alteration was recovered in TDs. The ultrastructural analysis, in turn, revealed greater quantity of Golgi apparatus cisterns in SDs, distinctly than TDs, which showed improvement in this diabetic condition. Thus, physical training was responsible for the recovery of some important diabetic alterations, possibly improving the motility of substances in the large intestine. Nevertheless, it cannot be considered alone in the treatment of this disease, requiring the combined practice of other methods.

Orocecal transit time and small intestinal bacterial overgrowth in type 2 diabetes patients from North India

BACKGROUND

Diarrhea, constipation, flatulence, and abdominal pain are common complaints in type 2 diabetes patients. Impaired intestinal motility is often followed by small intestinal bacterial overgrowth (SIBO). Therefore, this study was planned to determine the incidence of SIBO and its relation with orocecal transit time (OCTT) in type 2 diabetes patients.

SUBJECTS AND METHODS

SIBO and OCTT were measured by using noninvasive glucose and lactulose hydrogen breath tests, respectively. For this study, 84 patients with type 2 diabetes mellitus in the age range 30-65 years and 45 age-matched apparently healthy controls were enrolled.

RESULTS

The glucose hydrogen breath test was suggestive of SIBO in 15.5% of patients with type 2 diabetes mellitus but in one (2.2%) of controls. There was a significant increase (P<0.001) in OCTT in type 2 diabetes patients compared with controls. It was also observed that OCTT in type 2 diabetes patients with SIBO was significantly delayed (P<0.001) compared with type 2 diabetes patients without SIBO.

CONCLUSION

This study indicates that SIBO in diabetes patients may be due to delayed OCTT.

Neostigmine-induced contraction and nitric oxide-induced relaxation of isolated ileum from STZ diabetic guinea pigs

Both delayed gastrointestinal transit and autonomic neuropathy have been documented in patients with diabetes mellitus. The mechanism of neostigmine, an agent that mimics release of acetylcholine from autonomic neurons by prokinetic agents, to contract smooth muscle, despite dysfunctional enteric neural pathways, was determined using isolated ilea from STZ-treated and control guinea pigs. Both bethanechol- and neostigmine-induced contractions were stronger in diabetic ileum. Bethanechol-induced contractions of control but not diabetic ileum were increased by low dose scopolamine suggesting reduced activation of presynaptic muscarinic autoreceptors in diabetic ileum. The muscarinic receptor antagonist 4-DAMP strongly, but the nicotinic receptor antagonist hexamethonium only weakly, reduced neostigmine-induced contractions of control and diabetic ilea. The amount of acetylcholine, inferred from tissue choline content, was increased in diabetic ileum. Nicotinic neural and noncholinergic postjunctional smooth muscle receptors contributed more strongly to neostigmine-induced contractions in diabetic than control ileum. Relaxation of diabetic ileum by exogenous nitric oxide generated from sodium nitroprusside was comparable to control ileum, but smooth muscle relaxation by l-arginine using neuronal nitric oxide synthase to generate nitric oxide was weaker in diabetic ileum with evidence for a role for inducible nitric oxide synthase. Despite autonomic neuropathy, neostigmine strongly contracted ileum from diabetic animals but by a different mechanism including stronger activation of postjunctional muscarinic receptors, greater synaptic acetylcholine, stronger activation of noncholinergic excitatory pathways, and weaker activation of inhibitory pathways. A selective medication targeting a specific neural pathway may more effectively treat disordered gastrointestinal transit in patients with diabetes mellitus.

Efficacy and safety of sodium phosphate for colon cleansing in type 2 diabetes mellitus

OBJECTIVES

The need for colonoscopy is common among diabetic patients. However, there are no standards per se for bowel preparation in patients with type 2 diabetes. In this study, we evaluated the efficacy, safety, and tolerability of sodium phosphate (NaP), and the quality of bowel cleansing in relation to glycemic control and late complications.

METHODS

A total of 50 consecutive type 2 diabetic patients and 50 non-diabetic patients underwent bowel preparation by NaP. Fasting blood glucose, sodium (Na), potassium (K), calcium (Ca), phosphorus (P), magnesium, and creatinine levels were measured on the procedure day. Patients were given a tolerability questionnaire regarding symptoms.

RESULTS

With regard to bowel preparation quality, optimal bowel cleansing was achieved in 35 (70%) diabetic and 47 (94%) non-diabetic patients (P = 0.002). Abdominal pain or discomfort during and an hour after the procedure was similar in both groups (P >0.05). The changes in Na, K, Ca, P and creatinine levels after NaP use did not reach statistical significance between the groups (P >0.05). In the diabetic patients, there was a significant correlation between the quality of bowel cleansing and mean age, duration of diabetes mellitus, level of hemoglobin A1c (HbA1c), fasting blood glucose level, and diabetic late complications (P <0.05).

CONCLUSION

These data suggest that NaP is safe and tolerable in diabetic patients, but the quality of bowel cleansing is worse than in non-diabetic patients. These observations support the concept that the quality of bowel cleansing in those with type 2 diabetes is closely related to the duration and regulation of the disease and the presence of late complications.

Gastrointestinal symptoms in type-1 diabetes: is it all about brain plasticity?

BACKGROUND AND AIMS

Autonomic neuropathy seems to play a central role in the development of gastrointestinal symptoms in diabetes. In order to explore the neuronal mechanisms behind the symptoms we evaluated the brain processing of painful visceral stimuli.

METHODS

Evoked brain potentials were recorded to assess the response to painful oesophageal electrical stimuli in 15 healthy volunteers and 14 type-1 diabetes patients with autonomic neuropathy and related gastrointestinal symptoms. Source reconstruction analysis (fixed Multiple Signal Classification (MUSIC) algorithm) was applied to estimate the location of the evoked electrical activity in the brain.

RESULTS

The patients had increased oesophageal sensory thresholds compared to the controls (P=0.004). The latencies of the evoked brain potentials at vertex (Cz) were increased (P=0.007) and amplitudes reduced (P=0.011) in diabetics. Compared with controls the patients had a posterior shift of the electrical sources in the anterior cingulate cortex at 54 ms, and additional sources close to the posterior insula at 95 ms and in medial frontal gyrus at 184 ms.

CONCLUSIONS

There is evidence of altered central processing to visceral stimulation, and both peripheral and central mechanisms seem involved. Central neuronal reorganisation may contribute to our understanding of the gastrointestinal symptoms in patients with diabetic autonomic neuropathy and this may guide development and evaluation of new treatment modalities.

Immunohistochemical study of vasoactive intestinal peptide (VIP) enteric neurons in diabetic rats supplemented with L-glutamine

The purpose of this work was to study the area of the varicosities of nerve fibers of myenteric neurons immunoreactive to vasoactive intestinal peptide (VIP-IR) and of the cell bodies of VIP-IR submucosal neurons of the jejunum of diabetic rats supplemented with 2% L-glutamine. Twenty male rats were divided into the following groups: normoglycemic (N), normoglycemic supplemented with L-glutamine (NG), diabetic (D) and diabetic supplemented with L-glutamine (DG). Whole-mounts of the muscle tunica and the submucosal layer were subjected to the immunohistochemical technique for neurotransmitter VIP identification. Morphometric analyses were carried out in 500 VIP-IR cell bodies of submucosal neurons and 2000 VIP-IR varicosities from each group. L-Glutamine supplementation to the normoglycemic animals caused an increase in the areas of the cell bodies (8.49%) and varicosities (21.3%) relative to the controls (P < 0.05). On the other hand, there was a decrease in the areas of the cell bodies (4.55%) and varicosities (28.9%) of group DG compared to those of group D (P < 0.05). It is concluded that L-glutamine supplementation was positive both to normoglycemic and diabetic animals.

Metabolic basis for low urine pH in type 2 diabetes

BACKGROUND AND OBJECTIVES

Type 2 diabetes is associated with excessively low urine pH, which increases the risk for uric acid nephrolithiasis. This study was conducted to assess the metabolic basis responsible for the excessive urinary acidity of individuals with type 2 diabetes.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Nine non-stone-forming patients who had type 2 diabetes and low urine pH and 16 age- and body mass index-matched non-stone-forming volunteers without type 2 diabetes were maintained on a constant metabolic diet for 7 days, and 24-hour urine was collected on the last 2 days of the diet.

RESULTS

Urine dietary markers (potassium, sulfate, phosphorus, and urea nitrogen) were not different between the two groups. Patients with type 2 diabetes exhibited a significantly lower 24-hour urine pH (5.45+/-0.27 versus 5.90+/-0.42; P<0.01) and higher net acid excretion (NAE; 57+/-12 versus 38+/-18 mEq/d; P<0.01) compared with control subjects. The proportion of NAE excreted as ammonium (NH4+/NAE) was significantly lower in patients with type 2 diabetes than in control subjects (0.70+/-0.12 versus 0.94+/-0.36; P<0.01); however, the greater NAE in patients with type 2 diabetes was not accounted for by the differences in unmeasured urinary anions.

CONCLUSIONS

The overly acidic urine in patients with type 2 diabetes persists after controlling for dietary factors, body size, and age. The lower pH is due to a combination of greater NAE and lower use of ammonia buffers in patients with diabetes, which predisposes them to uric acid urolithiasis.

Relationship between clinical features and gastric emptying disturbances in diabetes mellitus

BACKGROUND AND OBJECTIVES

Gastric emptying (GE) may be delayed or rapid in diabetes mellitus. We sought to ascertain differences in risk factors or associated features (i.e. diabetic 'phenotype') among patients with diabetes who have rapid, slow or normal GE.

METHODS

From a database of patients in whom gastrointestinal transit was assessed by scintigraphy, we compared the diabetic phenotype in diabetic patients with rapid, slow and normal GE.

RESULTS

Of 129 patients, 55 (42%) had normal, 46 (36%) had delayed and 28 (22%) patients had rapid GE. In each GE category, there was an approximately equal number of type 1 and type 2 diabetes. In multivariable analyses, significant weight loss (OR, 2.81; 95% CI, 1.09-7.23) and neuropathy (OR, 3.60; 95% CI, 1.007-12.89) were the risk factors for delayed and rapid GE, respectively. Insulin therapy (OR, 0.08; 95% CI, 0.01-0.53) was associated with a lower risk of rapid compared to normal GE. However, other manifestations or characteristics of the diabetes 'phenotype' (i.e. type and duration of diabetes, glycosylated haemoglobin levels, and extraintestinal complications) were not useful for discriminating normal from delayed or rapid GE. At a specificity of 60%, clinical features were 73% sensitive for discriminating between normal and delayed GE and 80% sensitive for discriminating normal from rapid GE.

CONCLUSIONS

Diabetes is associated with slow and rapid GE. Because the diabetic phenotype is of limited utility for identifying disordered GE, GE should be assessed in patients with diabetes and gastrointestinal symptoms.

Visceral hypersensitivity and impaired accommodation in refractory diabetic gastroparesis

The pathophysiology of persistent gastrointestinal (GI) symptoms in patients with diabetic gastroparesis is poorly understood. Our aim was to evaluate gastric sensation and accommodation to a meal in patients with diabetic gastroparesis and refractory symptoms. We performed intermittent, phasic balloon distensions of the stomach using a gastric barostat device in 18 patients with diabetes and gastroparesis unresponsive to prokinetic therapy and in 13 healthy volunteers. We assessed the biomechanical, sensory and accommodation responses of the stomach, during fasting and after liquid meal. During balloon distension, the sensory thresholds for discomfort were lower (P < 0.02) in patients with diabetes than those in controls, in both the fasting and the postprandial states. The accommodation response to a meal was significantly impaired (P = 0.01) in patients with diabetes when compared to controls, although fasting gastric tone was similar (P = 0.08). Patients with diabetic gastroparesis and refractory GI symptoms demonstrate sensori-motor dysfunction of the stomach, comprising either impaired accommodation, gastric hypersensitivity or both. An objective evaluation of these biomechanical and sensory properties may provide valuable mechanistic insights that could guide therapy.

Type 1 diabetes attenuates the modulatory effects of endomorphins on mouse colonic motility

Our previous studies have shown that endomorphins (EMs), endogenous ligands for mu-opioid receptor, display a significant potentiation effect on mouse colonic motility. In the present study, to assess whether diabetes alters these modulatory effects of EMs on colonic motility, we investigated the effects of EMs in type 1 diabetic mouse colon in vitro. At 4 weeks after the onset of diabetes, carbachol-induced contractions in the longitudinal muscle of distal colon were significantly reduced compared to those of non-diabetic mice. Furthermore, the contractile effects induced by EMs in the longitudinal muscle of distal colon and in the circular muscle of proximal colon were also significantly reduced by type 1 diabetes. It is noteworthy that EMs-induced longitudinal muscle contractions were not significantly affected by atropine, Nomega-nitro-l-arginine methylester (l-NAME), phentolamine, propranolol, hexamethonium, methysergide and naltrindole. On the other hand, tetrodotoxin, indomethacin, naloxone, beta-funaltrexamine, naloxonazine and nor-binaltorphimine completely abolished these effects. These mechanisms responsible for EMs-induced modulatory effects in type 1 diabetes were in good agreement with those of non-diabetes, indicating similar mechanisms in both diabetes and non-diabetes. At 8 weeks after the onset of diabetes, both carbachol- and EMs-induced longitudinal muscle contractions were similar to those of short-time (4 weeks) diabetic mice. In summary, all the results indicated that type 1 diabetes significantly attenuated the modulatory effects of EMs on the mouse colonic motility, but the mechanisms responsible for these effects were not significantly altered.

Assessment of NADPH-diaphorase stained myenteric neurons of the jejunum of diabetic rats supplemented with ascorbic acid

The relation between hyperglycemia and diabetic neuropathy has already been demonstrated in some studies. Among the theories proposed for its etiology the oxidative stress stands out. The performance of nitric oxide as a link between the metabolic and vascular neuropathogenic factors that triggers the diabetic neuropathy has already been put forward. This study aimed to assess the quantification and measurements of the cell body profile area (CBPA) of NADPH-diaphorase reactive (NADPH-dp) myenteric neurons of the jejunum of diabetic rats (induced by streptozotocin) supplemented with Ascorbic Acid (AA). These changes in the myenteric neurons seem to be related to the gastrointestinal disturbances observed in diabetes mellitus (DM). Twenty male Wistar rats (Rattus norvegicus) were distributed in 4 groups (n=5): controls (C), control supplemented (CS), diabetic (D), and diabetic suplemented (DS). DM was induced by estreptozotocin (50mg/kg body wt). One week after the induction and confirmation of the DM (glycemia exam), animals of the groups CS and DS received 50mg of AA three times a week by gavage. After 90 days of experiment, the animals were anesthetized with lethal thiopental dose (40mg/kg) and the collected jejunum processed for the histochemistry NADPH-diaphorase technique. Whole-mount preparations were obtained for quantitative and morphometric analysis of the myenteric neurons. A quantity of jejunum neurons in the Group D (96±7.5) was not different (P>0.05) from Group DS (116±8.08), C (92±9.7), and CS (81±5.4), but in Group DS the quantity was higher (P<0.05) than in Group C and CS. The CBPA of neurons from Group D (189.50±2.68µm²) and DS (195.92±3.75µm²) were lower (P<0.05) than from Group C (225.13±4.37µm²) and CS (210.23±3.15µm²). The streptozotocin-induced DM did not change the jejunum-ileum area, the jejunum myenteric plexus space organization and the density of NADPH-dp neurons. The 50g AA-supplementation, three times a week, during 90 days, did not decrease hyperglycemia; however, it had a neuroprotective effect on the myenteric neurons, minimizing the increase on the CBPA of NADPH-dp neurons and increasing the amount of NADPD-dp neurons.

Gastroparesis in type 2 diabetes mellitus: prevalence, etiology, diagnosis, and treatment

The worldwide epidemic of type 2 diabetes mellitus (T2DM) is a substantial economic and social burden. Although gastroparesis associated with type 1 diabetes mellitus (T1DM) has been recognized for years, only recently have studies shown that patients with T2DM also have high rates of gastroparesis. Individuals with T2DM constitute 90% to 95% of the diabetic population. Unique characteristics that distinguish this population are obesity, insulin resistance, and associated comorbidities. These features highlight the importance of investigating gastric emptying in individuals with T2DM and upper gastrointestinal symptoms. The purpose of this review is to examine the literature pertaining to diabetes and the effect of diabetes on gastric neuromuscular function, with a focus on T2DM. An understanding of gastric motility in T2DM is important to diagnose gastroparesis, to treat upper gastrointestinal symptoms, and to restore normal gastric motility, which may lead, in turn, to improved glucose control.

Excitatory effects of synchronized intestinal electrical stimulation on small intestinal motility in dogs

The aim of this study was to investigate effects of synchronized intestinal electrical stimulation (SIES) on small intestinal motility in dogs. Seventeen dogs were equipped with a duodenal cannula for the measurement of small bowel motility using manometry; an additional cannula was equipped in six of the dogs with 1.5 m distal to the first one for the measurement of small intestinal transit. Two pairs of bipolar electrodes were implanted on the small intestinal serosa with an interval of 5 cm; glucagon was used to induce postprandial intestinal hypomotility. Eleven dogs were used for the assessment of the small intestinal contractions in both fasting and fed states. The other six dogs were used for the measurement of small intestinal transit. We found that 1) SIES induced small intestinal contractions during phase I of the migrating motor complex (MMC) (contractile index or CI: 5.2 +/- 0.6 vs. 10.3 +/- 0.7, P = 0.003); 2) in the fed state, SIES significantly improved glucagon-induced small intestinal postprandial hypomotility (CI: 3.4 +/- 0.5 vs. 6.0 +/- 0.3, P = 0.03); 3) SIES significantly accelerated small intestinal transit delayed by glucagon (70.4 +/- 3.1 vs. 44.5 +/- 3.1 min, P < 0.01); 4) there was a negative correlation between the CI and transit time (r = -0.427, P = 0.048); and 5) the excitatory effect of SIES was blocked by atropine. SIES may have a therapeutic potential for treating patients with small intestinal disorders.

Seventy-five gram glucose tolerance test to assess carbohydrate malabsorption and small bowel bacterial overgrowth

AIM: To investigate non-invasively the incidence of absorption of carbohydrates in diabetic patients during an oral glucose tolerance test (OGTT) and to determine whether malabsorption may be associated with insulin secretion and insulin resistance.

METHODS: A standard 75-g OGTT was performed in 82 diabetic patients. The patients received 75 g of anhydrous glucose in 225 mL of water after an overnight fasting and breath samples were collected at baseline and up to 120 min after ingestion. Breath hydrogen and methane concentrations were measured. Blood glucose and serum insulin concentrations were measured before ingestion and at 30, 60, 90, 120 min post-ingestion.

RESULTS: When carbohydrate malabsorption was defined as subjects with an increase of at least 10 ppm (parts per million) in hydrogen or methane excretion within a 2-h period, 28 (34%) had carbohydrate malabsorption. According to the result of increased breath test, 21 (75%) patients were classified as small bowel bacterial overgrowth and 7 (25%) as glucose malabsorption. Patients with carbohydrate malabsorption were older and had poor glycemic control as compared with those without carbohydrate malabsorption. The HOMA value, the sum of serum insulin during the test and the Δinsulin/Δglucose ratio were greater in patients with carbohydrate malabsorption.

CONCLUSION: Insulin resistance may be overestimated by using these markers if the patient has carbohydrate malabsorption, or that carbohydrate malabsorption may be present prior to the development of insulin resistance. Hence carbohydrate malabsorption should be taken into account for estimating insulin resistance and β-cell function.

Upper gastrointestinal sensory-motor dysfunction in diabetes mellitus

Gastrointestinal (GI) sensory-motor abnormalities are common in patients with diabetes mellitus and may involve any part of the GI tract. Abnormalities are frequently sub-clinical, and fortunately only rarely do severe and life-threatening problems occur. The pathogenesis of abnormal upper GI sensory-motor function in diabetes is incompletely understood and is most likely multi-factorial of origin. Diabetic autonomic neuropathy as well as acute suboptimal control of diabetes has been shown to impair GI motor and sensory function. Morphological and biomechanical remodeling of the GI wall develops during the duration of diabetes, and may contribute to motor and sensory dysfunction. In this review sensory and motility disorders of the upper GI tract in diabetes is discussed; and the morphological changes and biomechanical remodeling related to the sensory-motor dysfunction is also addressed.

Characteristics and predictive factors of early-onset diarrhoea during pelvic irradiation

This study reported characteristics and predictive factors of early-onset diarrhoea in patients receiving pelvic irradiation. We retrospectively reviewed 229 patients undergoing radiotherapy alone for cervical or uterine cancer. Oral barium was taken 90 min before simulation. According to contrast medium within small intestine only or colon in simulation films, we categorised patients as normal and rapid transit groups. Small or large volume of small-bowel was also evaluated according to barium distribution of simulation films. Whole-pelvic irradiation (39.6-45 Gy/22-25 fractions) was delivered to all patients initially. We recorded the onset of diarrhoea during pelvic irradiation. The rates of early-onset diarrhoea (<10 Gy) were compared between these two groups. The incidence of diarrhoea before 10 Gy was 7% and 17% (p = 0.138) in patients with normal and rapid transit, respectively. In multivariate analysis, interaction among rapid transit, prior abdomen operation and large small-bowel volume (p = 0.019) were noted for early-onset diarrhoea. Further subgroup analysis revealed that rapid transit (p = 0.046) was a significant factor in patients with both prior abdominal operation and large small-bowel volume. The incidence of early-onset diarrhoea was as high as 40% in this particular group. Patients experiencing early-onset diarrhoea had a higher incidence of moderate to severe diarrhoea (65%) than those without early-onset diarrhoea (23%) (p<0.001). In multivariate analysis, early-onset diarrhoea was the only factor of moderate to severe diarrhoea (p = 0.001). In conclusion, rapid small-bowel transit may be predisposed to early-onset diarrhoea during pelvic radiotherapy in patients with both prior abdominal operations and large small-bowel volume. Early-onset diarrhoea is considered as a predictive factor of diarrhoea of a higher grade.

Ileal brake failure in streptozotocin-induced diabetic rat

BACKGROUND

Diabetes mellitus frequently alters gastrointestinal function, but the pathophysiology of the diabetic gut has not been fully elucidated. Our aim was to characterize the enterogastric modulation of gastric emptying in an experimental model of diabetic rat and to determine the putative consequences of impaired regulation on glycaemic control.

METHODS

Studies were performed in streptozotozin-induced diabetic and control groups of male Sprague-Dawley rats. In rats fitted with chronic ileal cannulae, gastric emptying of a peptide meal was measured during ileal infusion of either lipids (ileal brake) or saline. The influence of the ileal brake mechanism on blood glucose levels after oral administration of a glucose solution was also evaluated.

RESULTS

Diabetic rats exhibited a precipitous gastric emptying (80% +/- 3% versus 57% +/- 3% in controls; P < 0.05). Ileal lipids delayed gastric emptying in control (38 +/- 4%; P < 0.05 versus ileal saline) but not in diabetic animals (77 +/- 5%; N.S. versus ileal saline). As the ileal brake contributes to the management of postprandial blood glucose levels (114 +/- 4.9 mg/dL after ileal lipids versus 134 +/- 7.8 mg/dL after ileal saline in control rats; P < 0.05), the failure of this mechanism in diabetic rats worsens glycaemic control after feeding (455 +/- 20.4 mg/dL after ileal lipids versus 399 +/- 8.7 mg/dL after ileal saline; P < 0.05).

CONCLUSION

Experimental diabetes impairs the ileal brake mechanism and disturbs gastric emptying. These abnormalities may contribute to difficult glycaemic control.

Effects of an aldose reductase inhibitor on gastroenteropathy in streptozotocin-diabetic rats

We investigated the effects of epalrestat, an aldose reductase inhibitor (ARI), on gastric emptying, fecal water content, and electrolyte transport in distal colon in streptozotocin (STZ)-induced diabetic rats. We measured gastric emptying time by acetaminophen method and short-circuit-current (Isc) in colonic mucosa using an Ussing chamber. The Isc in response to electric-field-stimulation (EFS) was decreased in untreated rats due to suppression by Cl- secretion. ARI treatment alleviated this suppression (2.7 +/- 0.6 vs. 7.4 +/- 1.1 microA/0.38 cm2 at 8 weeks after treatment, 1.1 +/- 0.2 vs. 7.0 +/- 1.0 at 12 weeks after treatment, P<0.05). In addition, the percentage of fecal water content in untreated rats was significantly lower than in ARI-treated rats (58.0 +/- 2.0 vs. 67.6 +/- 0.8% at 8 weeks, 56.9 +/- 2.1 vs. 63.4 +/- 1.4 at 12 weeks, P<0.05). From STZ injection to 8 weeks, the serum levels of acetaminophen in the diabetic rats were significantly lower than in controls, indicating delayed gastric emptying. At 12 weeks in the diabetic rats treated with ARI, the serum levels of acetaminophen were significantly higher than in the untreated diabetic rats (6.6 +/- 0.4 vs. 3.5 +/- 0.5 microg/ml, P<0.05). ARI-treatment ameliorated delayed gastric emptying without improving glycemic control. These findings show that ARI partially prevented progression of impaired gastric emptying, ion transport, and water transport, and suggest that epalrestat might be useful in the treatment of diabetic gastroenteropathy.

Prevalence of delayed gastric emptying in diabetic patients and relationship to dyspeptic symptoms: a prospective study in unselected diabetic patients

OBJECTIVE

Data on the prevalence of abnormal gastric emptying in diabetic patients are still lacking. The relation between gastric emptying and dyspeptic symptoms assessed during gastric emptying measurement has not yet been investigated. The aim was to investigate the prevalence of delayed gastric emptying in a large cohort of unselected diabetic patients and to investigate the relation between gastric emptying and gastrointestinal sensations experienced in the 2 weeks before and during the test meal, prospectively.

RESEARCH DESIGN AND METHODS

Gastric emptying was evaluated in 186 patients (106 with type 1 diabetes, mean duration of diabetes 11.6 +/- 11.3 years) using 100 mg (13)C-enriched octanoic acid added to a solid meal.

RESULTS

Gastric emptying was significantly slower in the diabetic subjects than in the healthy volunteers (T(50): 99.5 +/- 35.4 vs. 76.8 +/- 21.4 min, P < 0.003; Ret(120 min): 30.6 +/- 17.2 vs. 20.4 +/- 9.7%, P < 0.006). Delayed gastric emptying was observed in 51 (28%) diabetic subjects. The sensations experienced in the 2 weeks before the test were weakly correlated with the sensation scored during the gastric emptying test. Sensations assessed during the gastric emptying test did predict gastric emptying to some extent (r = 0.46, P < 0.0001), whereas sensations experienced in the previous 2 weeks did not.

CONCLUSIONS

This prospective study shows that delayed gastric emptying can be observed in 28% of unselected patients with diabetes. Upper gastrointestinal sensations scored during the gastric emptying tests do predict the rate of gastric emptying to some extent and sensation experienced during daily life does not.

Current concepts in diabetic gastroparesis

Diabetic gastroparesis is a common and debilitating condition affecting millions of patients with diabetes mellitus worldwide. Although gastroparesis in diabetes has been known clinically for more than 50 years, treatment options remain very limited. Until recently, the scientific literature has offered few clues regarding the precise aetiology of gastric dysfunction in diabetes.Up to 50% of patients with diabetes may experience postprandial abdominal pain, nausea, vomiting and bloating secondary to gastric dysfunction. There is no clear association between length of disease and the onset of delayed gastric emptying. Gastroparesis affects both type 1 (insulin dependent) and type 2 (non- insulin dependent) forms of diabetes. Diagnosis requires identifying the proper symptom complex, while excluding other entities (peptic ulcer disease, rheumatological diseases, medication effects). The diagnosis of gastroparesis may be confirmed by demonstrating gastric emptying delay during a 4-hour scintigraphic study. Treatment options are limited and rely on dietary modifications, judicious use of available pharmacological agents, and occasionally surgical or endoscopic placement of gastrostomies or jejunostomies. Gastric pacing offers promise for patients with medically refractory gastroparesis but awaits further investigation. Current pharmacological agents for treating gastroparesis include metoclopramide, erythromycin, cisapride (only available via a company-sponsored programme) and domperidone (not US FDA approved). All of these drugs act as promotility agents that increase the number or the intensity of gastric contractions. These medications are not uniformly effective and all have adverse effects that limit their use. Cisapride has been removed from the open market as a result of over 200 reported cases of cardiac toxicity attributed to its use. Unfortunately, there is a paucity of clinical studies that clearly define the efficacy of these agents in diabetic gastroparesis and there are no studies that compare these drugs to each other. The molecular pathophysiology of diabetic gastroparesis is unknown, limiting the development of rational therapies. New studies, primarily in animals, point to a defect in the enteric nervous system as a major molecular cause of abnormal gastric motility in diabetes. This defect is characterised by a loss of nitric oxide signals from nerves to muscles in the gut resulting in delayed gastric emptying. Novel therapies designed to augment nitric oxide signalling are being studied.

Current concepts in diabetic gastroparesis

Diabetic gastroparesis is a common and debilitating condition affecting millions of patients with diabetes mellitus worldwide. Although gastroparesis in diabetes has been known clinically for more than 50 years, treatment options remain very limited. Until recently, the scientific literature has offered few clues regarding the precise aetiology of gastric dysfunction in diabetes.Up to 50% of patients with diabetes may experience postprandial abdominal pain, nausea, vomiting and bloating secondary to gastric dysfunction. There is no clear association between length of disease and the onset of delayed gastric emptying. Gastroparesis affects both type 1 (insulin dependent) and type 2 (non- insulin dependent) forms of diabetes. Diagnosis requires identifying the proper symptom complex, while excluding other entities (peptic ulcer disease, rheumatological diseases, medication effects). The diagnosis of gastroparesis may be confirmed by demonstrating gastric emptying delay during a 4-hour scintigraphic study. Treatment options are limited and rely on dietary modifications, judicious use of available pharmacological agents, and occasionally surgical or endoscopic placement of gastrostomies or jejunostomies. Gastric pacing offers promise for patients with medically refractory gastroparesis but awaits further investigation. Current pharmacological agents for treating gastroparesis include metoclopramide, erythromycin, cisapride (only available via a company-sponsored programme) and domperidone (not US FDA approved). All of these drugs act as promotility agents that increase the number or the intensity of gastric contractions. These medications are not uniformly effective and all have adverse effects that limit their use. Cisapride has been removed from the open market as a result of over 200 reported cases of cardiac toxicity attributed to its use. Unfortunately, there is a paucity of clinical studies that clearly define the efficacy of these agents in diabetic gastroparesis and there are no studies that compare these drugs to each other. The molecular pathophysiology of diabetic gastroparesis is unknown, limiting the development of rational therapies. New studies, primarily in animals, point to a defect in the enteric nervous system as a major molecular cause of abnormal gastric motility in diabetes. This defect is characterised by a loss of nitric oxide signals from nerves to muscles in the gut resulting in delayed gastric emptying. Novel therapies designed to augment nitric oxide signalling are being studied.

Diagnosis and treatment of chronic gastroparesis and chronic intestinal pseudo-obstruction

Chronic gastroparesis and CIP are debilitating disorders that are difficult to treat with currently available therapies. Failure of proper migration and differentiation of enteric neurons or ICC can result from specific genetic mutations and lead to phenotypes of CIP with or without concomitant gastroparesis. Intestinal dysfunction in diabetes may reflect a depletion of NO production (and perhaps other neurotransmitters or modulators), which is manifest as a syndrome of gastroparesis, diarrhea, or constipation in individual patients. As the key molecular changes underlying these disorders are defined, clinicians will begin to understand their precise etiology and rational medical therapy may become possible. In the future, testable hypotheses regarding the etiology of other functional bowel disorders (e.g., functional dyspepsia, irritable bowel syndrome, and so forth) may be developed.

Aging and intestinal motility: a review of factors that affect intestinal motility in the aged

Normal aging is associated with significant changes in the function of most organs and tissues. In this regard, the gastrointestinal tract is no exception. The purpose of this review is to detail the important age-related changes in motor function of the various parts of the gastrointestinal tract and to highlight some of the important motility changes that may occur, either in relation to common age-related disorders, or as a result of certain drugs commonly prescribed in the aged. A major confounding factor in the interpretation of motor phenomena throughout the gastrointestinal tract in this age group is the frequent coexistence of neurological, endocrinological and other disease states, which may be independently associated with dysmotility. Overall, current data are insufficient to implicate normal aging as a cause of dysmotility in the elderly. Normal aging is associated with various changes in gastrointestinal motility, but the clinical significance of such changes remains unclear. More important is the impact of various age-related diseases on gastrointestinal motility in the elderly: for example, long-standing diabetes mellitus may reduce gastric emptying in up to 50% of patients; depression significantly prolongs whole-gut transit time; hypothyroidism may prolong oro-caecal transit time; and chronic renal failure is associated with impaired gastric emptying. In addition, various, frequently used drugs in the elderly cause disordered gastrointestinal motility. These drugs include anticholinergics, especially antidepressants with an anticholinergic effect, opioid analgesics and calcium antagonists.

Gastric emptying in diabetes: clinical significance and treatment

The outcome of recent studies has led to redefinition of concepts relating to the prevalence, pathogenesis and clinical significance of disordered gastric emptying in patients with diabetes mellitus. The use of scintigraphic techniques has established that gastric emptying is abnormally slow in approx. 30-50% of outpatients with long-standing Type 1 or Type 2 diabetes, although the magnitude of this delay is modest in many cases. Upper gastrointestinal symptoms occur frequently and affect quality of life adversely in patients with diabetes, although the relationship between symptoms and the rate of gastric emptying is weak. Acute changes in blood glucose concentration affect both gastric motor function and upper gastrointestinal symptoms. Gastric emptying is slower during hyperglycaemia when compared with euglycaemia and accelerated during hypoglycaemia. The blood glucose concentration may influence the response to prokinetic drugs. Conversely, the rate of gastric emptying is a major determinant of post-prandial glycaemic excursions in healthy subjects, as well as in Type 1 and Type 2 patients. A number of therapies currently in development are designed to improve post-prandial glycaemic control by modulating the rate of delivery of nutrients to the small intestine.

Small bowel disease in the elderly: diarrhoea and malabsorption

Diarrhoea and malabsorption are common problems in elderly persons. Worldwide, diarrhoea is the second leading cause of mortality. In the developed world, 85% of its mortality affects the elderly. The diagnostic work up for diarrhoea and malabsorption is more complex for the elderly than for the young patient. If diarrhoea persists for more than 24 h, oral rehydration solutions or intravenous fluids must be administered promptly in order to prevent hypotension and organ failure in the often multi-morbid patient. Both the immunocompromised patient and the severely affected out-patient should have stool culture performed. Malabsorption usually presents with weight loss, osteoporosis, anaemia, skin and neurological symptoms. The careful diagnostic work-up must aim at the identification of treatable disorders such as coeliac disease, Crohn's disease and bacterial overgrowth. Often, a detailed drug history is of help in identifying a readily treatable cause.

Enhanced colonic peristalsis by impairment of nitrergic enteric neurons in spontaneously diabetic rats

Changes in enteric neurons containing various neurotransmitters in the colon have been described in diabetic rats; however, how these changes are related to colonic motility disorders remains unclear. Nitric oxide (NO) is known to be an important inhibitory neurotransmitter in the enteric nervous system. In the present study, we investigated the peristaltic reflex using our modified Trendelenburg's method to evaluate the differences in enteric nitrergic neurons of the distal colon between spontaneously diabetic rats and their sibling control rats. We measured maximum intraluminal pressure, threshold pressure and propagation distance of the reflex contraction. These diabetic rats showed a greater maximum intraluminal pressure than that in the control rats. NG nitro-L-arginine methyl ester (L-NAME) significantly increased the maximum pressure in the control rats. Although L-arginine did not change the maximum pressure, sodium nitroprusside (SNP) significantly decreased it in these diabetic rats. Nicotinamide adenine dinucleotide phosphate (NADPH) diaphorase reactivities in the myenteric plexus were much weaker in the diabetic rats than those in the control rats. These results indicate that the colonic peristaltic reflex is enhanced by impairment of enteric nitrergic inhibitory neurons in spontaneously diabetic rats.

The correlation of depression and gastric dysrhythmia in functional dyspepsia

Psychologic factors in functional dyspepsia have been discussed in many previous articles. However, the relationship between depression and functional dyspepsia is still obscure. We investigated the impact of depression on clinical symptoms and gastric dysrhythmia in functional dyspepsia. Thirty-nine patients with functional dyspepsia and 18 healthy subjects were included. Patients were investigated with clinical symptoms assessment, Zung's self-rating depression scale, and electrogastrography. Patients with functional dyspepsia were divided into two groups: 21 patients with depression and 18 patients without depression. The depressed patients had similar total gastrointestinal symptom severity scores compared with the nondepressed patients, but with higher total symptom frequency scores (p < 0.05). With regards to symptoms, the depressed patients had higher abdominal fullness severity and frequency scores and nausea frequency scores. The patients with functional dyspepsia had a lower percentage of normal slow wave in both the fasting and fed states and a higher percentage of bradygastria in the fasting state and tachygastria in the postprandial state (p < 0.05). There was no significant difference in the percentage of bradygastria or tachygastria between the depressed and nondepressed patients. There was no correlation between the specific type of electrogastrographic abnormality and the presence or absence of depression in functional dyspepsia patients.

Colorectal symptoms in patients with neurological diseases

Several neurological diseases cause constipation or faecal incontinence restricting social activities and influencing quality of life. As several new treatment modalities have become available within the last few years, doctors treating patients with neurological diseases should be aware of the symptoms and have a basic knowledge of relevant treatment options. Constipation and faecal incontinence are common symptoms in patients with traumatic spinal cord injuries, spina bifida, multiple sclerosis, diabetic polyneuropathy, Parkinson's disease, stroke, and cerebral palsy. New treatment modalities are: prokinetic agents, enemas administered through the enema continence catheter or through an appendicostomy, and biofeed-back. Sacral nerve stimulation is still mostly at an experimental level and colostomy should be restricted to the few patients with most severe problems resistant to other therapy.

Prospective study of colorectal cancer risk and physical activity, diabetes, blood glucose and BMI: exploring the hyperinsulinaemia hypothesis

A sedentary lifestyle, obesity, and a Westernized diet have been implicated in the aetiology of both colorectal cancer and non-insulin dependent diabetes mellitus, leading to the hypothesis that hyperinsulinaemia may promote colorectal cancer. We prospectively examined the association between colorectal cancer risk and factors related to insulin resistance and hyperinsulinaemia, including BMI, physical activity, diabetes mellitus, and blood glucose, in a cohort of 75 219 Norwegian men and women. Information on incident cases of colorectal cancer was made available from the Norwegian Cancer Registry. Reported P values are two-sided. During 12 years of follow up, 730 cases of colorectal cancer were registered. In men, but not in women, we found a negative association with leisure-time physical activity (P for trend = 0.002), with an age-adjusted RR for the highest versus the lowest category of activity of 0.54 (95% CI = 0.37-0.79). Women, but not men, with a history of diabetes were at increased risk of colorectal cancer (age-adjusted RR = 1.55; 95% CI = 1.04-2.31), as were women with non-fasting blood glucose > or = 8.0 mmol l(-1)(age-adjusted RR = 1.98; 95% CI = 1.31-2.98) compared with glucose <8.0 mmol l(-1). Overall, we found no association between BMI and risk of colorectal cancer. Additional adjustment including each of the main variables, marital status, and educational attainment did not materially change the results. We conclude that the inverse association between leisure-time physical activity and colorectal cancer in men, and the positive association between diabetes, blood glucose, and colorectal cancer in women, at least in part, support the hypothesis that insulin may act as a tumour promoter in colorectal carcinogenesis.

Effects of postprandial walking on delayed gastric emptying and intragastric meal distribution in longstanding diabetics

OBJECTIVE

We investigated the influence of standardized postprandial walking on the rates of gastric emptying and of intragastric meal distribution in 50 consecutive patients with longstanding insulin-dependent diabetes mellitus.

METHODS

Gastric emptying of a semisolid meal labeled with 99mTc was continuously recorded with a dual-head gamma camera with patients in the supine position for 90 min before and 20 min after a 30-min postprandial walk. Regions of interest enclosing total stomach, and proximal and distal gastric compartments were calculated to determine gastric emptying rates and intragastric meal distribution.

RESULTS

The evaluation of gastric emptying rates before and after postprandial walking demonstrated two variants of delayed gastric emptying: one variant that was counteracted by postprandial walking in seven patients (14%, Group I) and another variant that was not influenced by postprandial walking in 11 patients (22%, Group II). In addition, the emptying rates of 28 patients (56%) were within the range of controls and in four patients the emptying was accelerated (8%). The filling of the proximal gastric compartment was predominant and remained dominant after walking in Groups I and II. In controls and in diabetics with normal gastric emptying, the preliminary predominant filling of the proximal compartment was equalized after walking and the proximal compartment regained predominance thereafter. The changes in gastric emptying characteristics from delayed to accelerated gastric emptying may be related to the duration of diabetes (r = -0.47, p<0.03) and were not indicated by symptoms of upper GI discomfort or by secondary diabetic manifestations.

CONCLUSION

Postprandial walking may improve gastric emptying in 14% of patients with longstanding insulin-dependent diabetes mellitus.

Gastrointestinal motor dysfunction, symptoms, and neuropathy in noninsulin-dependent (type 2) diabetes mellitus

Although relatively frequent. diabetic involvement of digestive tract motility has not been investigated extensively in different organs. The authors studied esophageal, gastric, and gallbladder motor function in 35 type 2 (noninsulin-dependent) diabetic patients to determine the extent of gut involvement. Of these patients, 27 (77%) had peripheral neuropathy, 12 (34%) had both peripheral and autonomic neuropathy, and 22 (63%) had gastrointestinal symptoms. Esophageal manometric abnormalities were recorded in 18 patients, and delayed radionuclide emptying of the esophagus was documented in 16 patients, with a 83% concordance between the two tests. Scintigraphic gastric emptying of solids was delayed in 56% of patients, whereas gallbladder emptying after cholecystokinin stimulation was reduced in 69% of them. In 74% of patients at least one of the viscera under investigation showed abnormal motor function; however, only 36% of patients displayed involvement of the three organs. Gastrointestinal symptoms, duration and therapy of diabetes, previous poor glycemic control, and retinopathy did not correlate with the presence or the extent of motor disorders. Neuropathy was not predictive of gastrointestinal involvement and its extent; however, when motor abnormalities were present in patients with neuropathy, these were usually more severe. Gastrointestinal motor disorders are frequent and widespread in type 2 diabetics, regardless of symptoms. Autonomic neuropathy has a poor predictive value on motor disorders (0.75 for the esophagus, 0.5 for the stomach, 0.8 for the gallbladder), thus suggesting the coexistence of other pathophysiologic mechanisms.

Cisapride versus placebo for 8 weeks on glycemic control and gastric emptying in insulin-dependent diabetes: a double blind cross-over trial

In insulin-dependent diabetes mellitus, slow gastric emptying may make absorption unpredictable and foster glycemic instability. Cisapride accelerates emptying, but controlled long term studies are scarce, and effects on glycemic control unknown. We investigated, in patients with insulin-dependent diabetes mellitus and unstable glycemia, the effects of 10 mg cisapride 4 times daily for 8 weeks vs. placebo on glycemic control and gastric emptying under random, cross-over, double blind conditions. In 14 patients with delayed and 9 with nondelayed emptying, blood glucose variability over 28-week treatment periods separated by a 4-week wash-out and gastric emptying of a semisolid 1168-kJ meal immediately after the treatment periods were assessed. Cisapride did not affect glycemic control [SD of within-patient mean blood glucose, 4.2 mmol/L +/-0.1 (+/- SEM) vs. 4.0+/-0.1 mmol/L after placebo; hemoglobin A1c, 8.3+/-0.2% vs. 8.5+/-0.2%]. Emptying was faster after cisapride than after placebo in 8 of 14 patients with delayed vs. 7 of 9 with nondelayed emptying (P = NS) and in 11 of 15 without vs. 4 of 8 with cardiovascular autonomic neuropathy (P = NS). Autonomic neuropathy prevailed in 7 of 14 patients with delayed and 1 of 9 with nondelayed emptying. Blood glucose immediately before and during assessment of emptying was unrelated to the emptying rate, whereas blood glucose increases over fasting levels were greater with faster emptying (P<0.002). In conclusion, cisapride's effects were not different from those of placebo on glycemic control and gastric emptying, it did not differently affect patients with delayed vs. nondelayed emptying, and it slightly accelerated emptying (P = NS) in patients without, but not in those with, cardiovascular autonomic neuropathy. Blood glucose levels before and during assessment of emptying did not affect emptying, but the glucose rise over fasting levels was greater with faster emptying.

Gastric emptying in diabetes mellitus: relationship to blood-glucose control

The application of novel investigative techniques has established that disordered gastric motility is a frequent complication of diabetes mellitus. Thus, gastric emptying of solid or nutrient liquid meals is abnormal in 30% to 50% of randomly selected outpatients with long-standing type 1 or type 2 diabetes. Delayed gastric emptying occurs more frequently than rapid emptying. There is increasing evidence that disordered gastric motility has a major impact on the management of patients with diabetes mellitus by leading to gastrointestinal symptoms and poor glycemic control. Although both gastroparesis and upper gastrointestinal symptoms have been attributed to irreversible autonomic damage, it is now clear that acute changes in the blood-glucose concentration have a major effect on both gastrointestinal motor function and the perception of sensations arising in the gut. For example, there is an inverse relationship between the rate of gastric emptying and the blood-glucose concentration, so that gastric emptying is slower during hyperglycemia and accelerated during hypoglycemia. This article reviews some issues in the etiology, diagnosis, and management of problems associated with gastric emptying in elderly persons with diabetes mellitus.

Gastric emptying in patients with type I diabetes mellitus

Diabetic autonomic neuropathy is a known complication of long-standing diabetes. The present study was designed to study the prevalence of asymptomatic prolonged gastric emptying (GE) in young patients with IDDM and its correlations with disease duration and autonomic nerve function. The study population included 40 poorly controlled patients, mean age 17.6 +/- 4.6 years, with a disease duration of 1-17.5 years, and 20 age- and sex-matched controls. Autonomic nerve functions were assessed by standard cardiovascular reflexes, and gastrointestinal (GI) symptoms were assessed by a detailed questionnaire. GE was assessed by electrical impedance tomography (EIT), at 2 hours after a standard semisolid meal. Mean half-time gastric emptying was significantly prolonged in diabetic patients, 54.80 +/- 26.63 versus 40.37 +/- 8.62 min (p < 0.05), with a higher prevalence in the first 3 years and after 10 years of disease duration. No differences were found between diabetics and controls regarding cardiovascular tests. No correlations were found between age, GI scores, cardiovascular tests, and GE. Patients with IDDM may suffer from prolonged GE. This is not always accompanied by autonomic impairments. As impaired gastric emptying may involve poor glycemic control and early satiety, patients with difficulties in metabolic control or poor caloric intake should be studied for the possibility of delayed gastric emptying.