Dyspepsia and gastric emptying in end-stage renal disease patients on hemodialysis

The prevalence of functional dyspepsia using Rome IV questionnaire among chronic kidney disease patients

Background: Symptoms of dyspepsia are usually encountered by chronic kidney disease patients. Abdominal discomfort is commonly seen in CKD patients with no other causes of organic affection. Aim: to determine the prevalence of functional dyspepsia in CKD patients, and which subtype is predominant in them. Materials and patients: This observational study included 150 CKD patients. Clinical and laboratory data were recorded for every patient. All the patients were interviewed using the ROME IV questionnaire of functional dyspepsia. Patients fulfilling criteria for functional dyspepsia were exposed to upper GI endoscopy. Results: Overall, 73 (48.7%) of CKD patients were males and 77 (51.3%) were females with mean age of (45.71 ± 9.59) and mean BMI (26.58 ± 5.39). The frequency of functional dyspepsia among CKD patients was determined to be 14.7% (22 out of 150 patients). Among those affected by functional dyspepsia, the most prevalent subtype was found to be Epigastric Pain Syndrome (EPS), accounting for 59% (13 out of 22 cases). The most common predictor of FD in CKD patients was chronic HCV infection, hemodialysis, stage of CKD and eGFR as revealed by Univariate regression analysis. Conclusion: The prevalence of FD amongst CKD patients is 14.7% with EPS the predominant subtype. Male patients, HCV patients, patients with higher CKD stages and highly impaired eGFR (low eGFR) are more probable to have FD.

Gastrointestinal challenges in nephropathic cystinosis: clinical perspectives

Gastrointestinal (GI) sequelae, such as vomiting, hyperacidity, dysphagia, dysmotility, and diarrhea, are nearly universal among patients with nephropathic cystinosis. These complications result from disease processes (e.g., kidney disease, cystine crystal accumulation in the GI tract) and side effects of treatments (e.g., cysteamine, immunosuppressive therapy). GI involvement can negatively impact patient well-being and jeopardize disease outcomes by compromising drug absorption and patient adherence to the strict treatment regimen required to manage cystinosis. Given improved life expectancy due to advances in kidney transplantation and the transformative impact of cystine-depleting therapy, nephrologists are increasingly focused on addressing extra-renal complications and quality of life in patients with cystinosis. However, there is a lack of clinical data and guidance to inform GI-related monitoring, interventions, and referrals by nephrologists. Various publications have examined the prevalence and pathophysiology of selected GI complications in cystinosis, but none have summarized the full picture or provided guidance based on the literature and expert experience. We aim to comprehensively review GI sequelae associated with cystinosis and its treatments and to discuss approaches for monitoring and managing these complications, including the involvement of gastroenterology and other disciplines.

Ultrasound evaluation of gastric residual volume in fasting end-stage renal failure patients

STUDY OBJECTIVE

To evaluate the gastric contents and gastric residual volume in patient with end-stage renal failure by gastric ultrasound.

DESIGN

Prospective observational study.

SETTING

Tertiary care teaching hospital.

PATIENTS

Adults of either gender with BMI < 40 kg/m2 with end-stage renal failure scheduled to undergo arteriovenous graft or fistula.

INTERVENTIONS & MEASUREMENTS

The cross-sectional area of the gastric antrum was measured by gastric ultrasound with patient in both supine and right lateral decubitus positions. The volume of the gastric contents were calculated using suitable validated formula. In addition, the nature of the gastric contents was also determined by gastric ultrasound.

MAIN RESULTS

The incidence of delayed gastric emptying was found to be 57.7% in the population studied despite following the prescribed preoperative standard fasting guidelines.

CONCLUSIONS

There is a high incidence of delayed gastric emptying in patients with end-stage renal failure presenting for surgery which may predispose them to risk of pulmonary aspiration perioperatively.

Comparison of palonosetron and ondansetron in preventing postoperative nausea and vomiting in renal transplantation recipients: a randomized clinical trial

BACKGROUND

End-stage renal diseases patients have a high risk of postoperative nausea and vomiting (PONV), which is multifactorial and need acute attention after renal transplantation for a successful outcome in term of an uneventful postoperative period. The study was done to compare the efficacy of palonosetron and ondansetron in preventing early and late-onset PONV in live donor renal transplantation recipients (LDRT).

METHODS

The prospective randomized double-blinded study was done on 112 consecutive patients planned for live donor renal transplantation. Patients of both sexes in the age group of 18...60 years were randomly divided into two groups: Group O (Ondansetron) and Group P (Palonosetron) with 56 patients in each group by computer-generated randomization. The study drug was administered intravenously (IV) slowly over 30.ßseconds, one hour before extubation. Postoperatively, the patients were accessed for PONV at 6, 24, and 72.ßhours using the Visual Analogue Scale (VAS) nausea score and PONV intensity scale.

RESULTS

The incidence of PONV in the study was found to be 30.35%. There was significant difference in incidence of PONV between Group P and Group O at 6.ßhours (12.5% vs. 32.1%, p.ß=.ß0.013) and 72.ßhours (1.8% vs. 33.9%, p.ß<.ß0.001), but insignificant difference at 24.ßhours (1.8% vs. 10.7%, p.ß=.ß0.113). VAS-nausea score was significantly lower in Group P as compared to Group O at a time point of 24.ßhours (45.54.ß...ß12.64 vs. 51.96.ß...ß14.70, p.ß=.ß0.015) and 72.ßhours (39.11.ß...ß10.32 vs. 45.7.ß...ß15.12, p.ß=.ß0.015).

CONCLUSION

Palonosetron is clinically superior to ondansetron in preventing early and delayed onset postoperative nausea and vomiting in live-related renal transplant recipients.

Progress in the study of nutritional status and selenium in dialysis patients

Malnutrition is very common in patients with chronic kidney disease, especially in those on maintenance dialysis. Malnutrition is one of the major factors affecting survival and death of dialysis patients, and reducing their activity tolerance and immunity. There are numerous and interacting risk factors for malnutrition, such as reduced nutritional intake, increased energy expenditure, hormonal disorders, and inflammation. Selenium, in the form of selenoproteins, is involved in many physiological processes in the body and plays an important role in maintaining redox homeostasis. Oxidative stress and infection are very common in dialysis patients, and selenium levels in dialysis patients are significantly lower than those in the healthy population. It has been shown that there is a correlation between selenium levels in hemodialysis patients and their nutrition-related indicators, and that selenium supplementation may improve malnutrition in patients. However, further studies are needed to support this conclusion and there is a lack of basic research to further characterize the potential mechanisms by which selenium may improve malnutrition in dialysis patients. The purpose of this review is to provide a comprehensive overview of factors associated with malnutrition in dialysis patients and to describe the progress of research on nutritional status and selenium levels in dialysis patients.

Comparison of Gastrointestinal Symptoms between Patients Undergoing Hemodialysis and Healthy Population

Background: Patients with end-stage renal disease (ESRD) complain of many gastrointestinal (GI) problems. The goal of the current study was to compare the prevalence of GI disorders in a relatively large group of patients with ESRD with healthy participants. Methods: In a matched case-control study, 597 patients undergoing hemodialysis and 740 healthy participants were investigated. All subjects were asked to complete Rome III questionnaire, including five modules to evaluate GI disorders. The Hospital Anxiety and Depression questionnaire, as well as the 12-general health questionnaire for psychological disorders assessment, were used. Results: Our results showed that in patients undergoing hemodialysis, the prevalence of irritable bowel syndrome (IBS) (OR=1.75), gastroesophageal reflux disease (GERD) (OR=1.55), and dyspepsia (OR=3.39) was significantly higher than in healthy control participants, while no significant difference was found in terms of constipation (OR=0.88). The association remained significant for dyspepsia and IBS even after controlling for psychological disorders as important potential confounding variables. On the other hand, adjustment for psychological disorders led to an insignificant association between hemodialysis and GERD. Surprisingly a significant relationship was observed between constipation and hemodialysis after adjustment for mentioned psychological factors. Conclusion: Our results showed that there was a significant relationship between hemodialysis and some GI complaints such as IBS, dyspepsia, GERD, and bloating. Psychological disorders only influence GERD prevalence in patients undergoing hemodialysis.

Delayed gastric emptying in nondiabetic patients with end-stage kidney disease

Objective

This study aimed to assess the gastric emptying capacity in nondiabetic patients with end-stage kidney disease (ESKD) by ultrasound.

Methods

Consecutive hemodialysis patients with ESKD (n = 37) and healthy controls (n = 37) were enrolled. All ESKD patients underwent ultrasound examinations on the day of hemodialysis (dialysis day) and the day after hemodialysis (nondialysis day). Standard ultrasound examinations were performed after overnight fasting, immediately after a light meal, and at 6 h after a meal. The antral cross-sectional area and gastric emptying according to the Perlas grading system were evaluated.

Results

Compared with the controls, patients with ESKD, on both dialysis and non-dialysis days, had significantly larger antral areas when examined in the supine position (p = 0.002 and p = 0.003, respectively), but not in the right lateral decubitus position (p = 0.452 and p = 0.512, respectively). In the supine position, the antral area of ESKD patients before dialysis (8 a.m. on the dialysis day) was larger than that at the same time on the nondialysis day (p = 0.028). The controls had a Perlas grade of either 0 or 1 at 6 h after a meal, whereas five patients (13.5%) and 11 patients (29.7%) in the ESKD group had Perlas grade 2 on the dialysis and non-dialysis days, respectively. Among patients with or without delayed gastric emptying, no differences were detected in the dialysis duration or levels of biochemical markers, except blood urea nitrogen (p = 0.038) and serum creatinine (p = 0.003).

Conclusion

Nondiabetic patients with ESKD had significantly delayed gastric emptying. Hemodialysis might improve gastric emptying and reduce gastric emptying delay.

Dyspepsia in Montenegrin chronic kidney disease patients undergoing hemodialysis: endoscopic and histopathological features

PURPOSE

The main purpose of this study was to analyze the characteristics of dyspepsia and contributing factors in Montenegrin maintenance hemodialysis patients.

METHODS

The study included 43 patients undergoing hemodialysis with symptoms of dyspepsia and 40 control dyspeptic subjects with preserved kidney function. All subjects underwent an interview about dyspeptic symptoms, physical and biochemical examination, and upper gastrointestinal endoscopy with pathohistological analysis of biopsy specimens.

RESULTS

Early satiety, bloating and heartburn were the most common symptoms in hemodialysis patients but without significant difference in frequency in relation to controls. Chronic kidney disease patients had statistically lower concentration of total proteins and albumin (p < 0.001), as well lower BMI values (p = 0.002). Despite this, no significant correlation of laboratory parameters with dyspeptic symptoms was found. Pathohistological examination indicated that the most common finding in hemodialysis patients was chronic active gastritis (58%), while chronic atrophic gastritis was significantly more common in dialytic patients (p = 0.032). Patients on hemodialysis had more frequently atrophy of corpus mucosa, which was positively related to dialysis duration (p = 0.001) and negatively related to pH values (p = 0.004) and bicarbonate concentration (p = 0.049). Helicobacter pylori was considerably more common in patients who underwent shorter time on hemodialysis (p < 0.001) and had higher values of bicarbonate (p = 0.037).

CONCLUSION

Maintenance hemodialysis patients are at risk for chronic gastric diseases that correlated with both dialysis vintage and duration.

The Prevalence of Helicobacter Pylori Infection in Patients with Chronic Kidney Disease Undergoing Hemodialysis

The aim of this study was to analyze the prevalence of Helicobacter pylori infection and gastroduodenal lesions in Montenegrin patients with chronic kidney disease on hemodialysis. The study included 55 hemodialysis patients with dyspeptic symptoms and 50 control subjects with normal kidney function who had also dyspepsia. After dyspepsia assessment by an interview, all subjects underwent gastroduodenoscopy and histopathological analysis of biopsy specimens, taken from the corpus and antrum of the stomach. Helicobacter pylori was confirmed in 50.9% of corpus mucosa i.e. 60.6% of antrum mucosa of maintenance hemodialysis patients. There were no significantly differences in endoscopic findings of the stomach and bacterial presence between the two study groups of participants (p = 0.451), while duodenal lesions were prevalent in control subjects (p < 0.001). The atrophy of corpus mucosa was more common in hemodialysis patients (p = 0.007), especially in those who have been on hemodialysis for a longer time (p < 0.001) and had lower pH (p = 0.011). The prevalence of Helicobacter pylori infection shown an inverse relationship with dialysis duration. Contrary, a positive relationship between Helicobacter pylori and the concentration of bicarbonate was demonstrated (p = 0.031). The prevalence of Helicobacter pylori and atrophic mucosal changes in Montenegrin hemodialysis patients depends on dialysis duration and acid-base balance.

Gastrointestinal symptoms in HIV-positive kidney transplant candidates and recipients from an HIV-positive donor

Gastrointestinal symptoms (GIS) are common in kidney transplant candidates and recipients and may be worsened by HIV. Objective: To determine the frequency and severity of GIS in HIV-positive kidney transplant recipients from HIV-positive donors, and those waiting to receive one. A GIS rating scale (GSRS) was completed by 76 participants at baseline and at 6 months. GIS frequency was defined as having at least one symptom (GSRS > 1). Severity was indicated by the GSRS score. Transplant candidates: GIS frequency was 88.9% and 86.3% at baseline and 6 months respectively. Indigestion was the most frequent (79.6% and 66.7% at baseline and 6 months), and severe GIS (GSRS 2.3). Women reported global mean (p = 0.030) severity significantly more than men. Transplant recipients: GIS frequency was 95.2% and 76.2% at baseline and 6 months respectively. At both assessment points, indigestion occurred most frequently (85.7% and 61.9% respectively). Highest GSRS was reported for indigestion at baseline (2.33) and at 6 months (1.33). Waist circumference (WC) was positively associated with the severity of constipation GSRS. GIS are common in both groups, especially indigestions. WC in transplant recipients should be monitored.

Delayed Gastric Emptying among Indian Patients with Non-Diabetic Chronic Kidney Disease

Introduction:

Upper gastrointestinal symptoms such as nausea, vomiting, abdominal bloating, and poor appetite are more frequent among chronic kidney disease (CKD) patients and may contribute to poor nutritional intake and malnutrition. Delayed gastric emptying (GE), one of the important contributors to these symptoms, has not been evaluated systematically in different stages of non-diabetic CKD, among Indian patients.

Materials and Methods:

This hospital-based, cross-sectional analytical study aimed to find out the frequency of delayed GE in non-diabetic CKD (stages: 3,4,5) patients and also to study the correlation between delayed GE and symptoms of gastroparesis, autonomic neuropathy and nutritional parameters. Patients were subjected to evaluation of symptoms of gastroparesis by standardized questionnaire (gastroparesis cardinal symptom index), nutritional status (by anthropometric measures and serum albumin), autonomic function by heart rate variability (HRV) and GE by gastric scintigraphy with a standardized solid rice idli (savory cake) meal labeled with technetium-99m sulfur colloid.

Results:

Of the 89 non-diabetic CKD (stages-3,4,5) patients evaluated, 22 (≈25%) had delayed GE and 8 (≈9%) rapid GE. Prevalence of delayed GE was higher among stage 5 (15/49, 31%) compared to stages 3 and 4 (7/40, 17.5%), though the difference was statistically insignificant. There was no association between delayed GE and symptoms of gastroparesis and autonomic neuropathy. Though not statistically significant, nutritional parameters (body mass index, skinfold thickness, and serum albumin) were poorer in the delayed GE group compared to the rest.

Conclusion:

Delayed GE, irrespective of symptoms, may contribute to malnutrition and hence should be looked for in non-diabetic CKD patients with unexplained malnutrition.

Dietary modifications achieved successful resolution of symptoms of gastroparesis diagnosed by demonstrating gastric food retention after overnight fasting in diabetic dialysis patients: two case reports with literature review

Background

Gastroparesis is frequently overlooked and difficult to treat. The diagnosis of gastroparesis requires standard upper gastrointestinal endoscopy to exclude gastric outlet obstruction and objective evidence demonstrating delayed gastric emptying. However, none of the internationally recommended methods for measuring gastric emptying including scintigraphy are covered by the Japanese health insurance system. Limitations in the diagnosis might be related to the disease being overlooked in Japan. Meanwhile, presence of retained food in the stomach after overnight fasting without obstruction is classically known to be suggestive of gastroparesis. Some recent reports have considered gastric food retention after an overnight fasting equivalent to delayed gastric emptying.

Case presentation

Two diabetic dialysis patients presented with nausea, vomiting, and oral feeding intolerance in the absence of mechanical obstruction. Abdominal computed tomography, upper gastrointestinal endoscopy, and ultrasonography demonstrated gastric food retention after overnight fasting. The findings led to the diagnosis of gastroparesis. Appropriate dietary modifications alone successfully relieved the symptoms despite persistent delayed gastric emptying.

Conclusions

Demonstrating retained food residue after fasting for sufficient duration might be a diagnostic alternative. Dietary modifications alone provided significant clinical benefits. Possible approaches for the diagnosis and treatment of gastroparesis in Japan should be investigated.

Chronic Kidney Disease as Oxidative Stress- and Inflammatory-Mediated Cardiovascular Disease

Generating reactive oxygen species (ROS) is necessary for both physiology and pathology. An imbalance between endogenous oxidants and antioxidants causes oxidative stress, contributing to vascular dysfunction. The ROS-induced activation of transcription factors and proinflammatory genes increases inflammation. This phenomenon is of crucial importance in patients with chronic kidney disease (CKD), because atherosclerosis is one of the critical factors of their cardiovascular disease (CVD) and increased mortality. The effect of ROS disrupts the excretory function of each section of the nephron. It prevents the maintenance of intra-systemic homeostasis and leads to the accumulation of metabolic products. Renal regulatory mechanisms, such as tubular glomerular feedback, myogenic reflex in the supplying arteriole, and the renin-angiotensin-aldosterone system, are also affected. It makes it impossible for the kidney to compensate for water-electrolyte and acid-base disturbances, which progress further in the mechanism of positive feedback, leading to a further intensification of oxidative stress. As a result, the progression of CKD is observed, with a spectrum of complications such as malnutrition, calcium phosphate abnormalities, atherosclerosis, and anemia. This review aimed to show the role of oxidative stress and inflammation in renal impairment, with a particular emphasis on its influence on the most common disturbances that accompany CKD.

EFFECT OF CHRONIC RENAL DYSFUNCTION ON THE PERMEABILITY OF THE COLON TO WATER AND ELECTROLYTES: EXPERIMENTAL STUDY IN RATS

Background:

Renal insufficiency is a disease that affects several organs by provoking hypervolemia and uremia. The disease reaches more than 500 million people worldwide and few studies bring their influence on the gastrointestinal tract.

Aim:

To evaluate the influence of 5/6 nephrectomy-induced hypervolemia on colonic permeability to water and electrolytes.

Method:

Sixty male Wistar rats weighing between 280-300 g were divided into three groups: 3, 7 and 14 days after nephrectomy, each one having a false-operated/control and partially nephrectomized. For colonic permeability they were submitted to colonic perfusion with a solution of Tyroad containing phenolphthalein. Differences among the concentrations of Na+, K+ and Cl- were used to calculate the rate of colonic permeability for the electrolytes. Phenolphthalein concentrations were used to evaluate the rate of secretion and water absorption.

Results:

The colonic secretion of water and electrolytes occurred expressively in the group seven days after nephrectomy. Hemodynamic and biochemical assessments determined the progression of renal failure in all three groups and polyethylene glycol was shown to be effective in reversing the secretory capacity of the colon.

Conclusion:

Hypervolemia established after 7 days post-nephrectomy 5/6 caused marked colonic secretion for water and electrolytes. The organism presents progressive colonic secretion as the blood volume increases; on the other hand, polyethylene glycol was able to revert this secretory framework of the colon to water and electrolytes by reversing the hypervolemia.

Role of Gastric Emptying in Symptoms of Gastroparesis

The symptoms of gastroparesis, such as nausea, vomiting, postprandial fullness, early satiety and abdominal pain, frequently impair the quality of life of the affected individuals. The diagnosis of gastroparesis is made after structural etiologies are ruled out and an assessment of gastric function shows delayed gastric emptying. The role of the delay in gastric emptying in the pathogenesis of symptoms of gastroparesis has been debated, with some studies suggesting an association between delayed gastric emptying and the upper gastrointestinal symptoms, while others do not. The recent literature supports the importance of using reliable methods to assess gastric emptying, as delay in gastric emptying measured on a reliable test (4-h scintigraphy or breath test) is associated with the severity of upper gastrointestinal symptoms. In addition to measuring total gastric emptying, evaluation of regional gastric retention in the proximal and distal stomach and whole gut transit to assess small intestinal and colonic transit may provide additional useful information in patients with more generalized symptoms of gastrointestinal dysmotility.

Association between delayed gastric emptying and upper gastrointestinal symptoms: a systematic review and meta-analysis

BACKGROUND

The relationship between delayed gastric emptying and upper GI symptoms (UGI Sx) is controversial.

OBJECTIVE

To assess association between gastric emptying and UGI Sx, independent of treatment.

DESIGN

We performed a systematic review and meta-analysis of the literature from 2007 to 2017, review of references and additional papers identified by content expert. We included studies evaluating the association between gastric emptying and nausea, vomiting, early satiety/postprandial fullness, abdominal pain and bloating. Covariate analyses included optimal gastric emptying test method, gastric emptying type (breath test or scintigraphy) and patient category. Meta-regression compared the differences based on type of gastric emptying tests.

RESULTS

Systematic review included 92 gastric emptying studies (26 breath test, 62 scintigraphy, 1 ultrasound and 3 wireless motility capsule); 25 of these studies provided quantitative data for meta-analysis (15 scintigraphy studies enrolling 4056 participants and 10 breath test studies enrolling 2231 participants). Meta-regression demonstrated a significant difference between optimal and suboptimal gastric emptying test methods when comparing delayed gastric emptying with nausea and vomiting. On evaluating studies using optimal gastric emptying test methodology, there were significant associations between gastric emptying and nausea (OR 1.6, 95% CI 1.4 to 1.8), vomiting (OR 2.0, 95% CI 1.6 to 2.7), abdominal pain (OR 1.5, 95% CI 1.0 to 2.2) and early satiety/fullness (OR 1.8, 95% CI 1.2 to 2.6) for patients with UGI Sx; gastric emptying and early satiety/fullness in patients with diabetes; gastric emptying and nausea in patients with gastroparesis.

CONCLUSIONS

The systematic review and meta-analysis supports an association between optimally measured delayed gastric emptying and UGI Sx.

Gastrointestinal motility in patients with end-stage renal disease on chronic hemodialysis

BACKGROUND

Previous studies indicated delayed gastric emptying in patients with end-stage renal disease (ESRD) using indirect methods. The objective of the current study was to examine gastrointestinal motility using a direct method as well as the role of the incretin hormones and glucagon.

METHODS

Patients on chronic hemodialysis and with either normal glucose tolerance, impaired glucose tolerance or type 2 diabetes, and healthy control subjects (N = 8, respectively) were studied. Gastric emptying time was measured by repeated gamma camera imaging for 6 hours after intake of a radioactive labeled standardized mixed solid and liquid meal. Glucagon, glucagon-like peptide-1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP) levels were measured.

KEY RESULTS

Patients were age, gender and BMI matched with controls. We found significantly higher gastric retention at 15 minutes, prolonged gastric mean emptying time, and gastric half-emptying time of the solid marker in all three groups of ESRD patients compared to controls. Significant differences in mean total area under the concentration curve (AUC) values across the four groups for GIP (P = 0.001), but not for GLP-1 and glucagon. The ESRD group had significant higher total AUC of GIP and glucagon compared to controls (P < 0.001 and P < 0.04) but not for GLP-1 (P = 0.4). No difference in incremental AUC was found.

CONCLUSIONS AND INFERENCES

We found altered gastrointestinal motility in dialysis patients, with higher gastric retention and prolonged gastric emptying, and higher total AUC of GIP and glucagon independent of the presence of diabetes or prediabetes.

Dyspepsia Amongst End Stage Renal Disease Undergoing Hemodialysis: Views from a Large Tertiary Care Center

Background and Objectives

Gastrointestinal symptoms are common in patients with end stage renal disease (ESRD) among which dyspepsia is frequently observed. The aim of the study was to determine the frequency and associations of dyspepsia in ESRD patients using the Leeds questionnaire.

Methods

All ESRD patients on maintenance hemodialysis were consecutively enrolled in the study. Leeds questionnaire was used to interrogate the patients for the assessment of dyspepsia. Mean and standard deviation were calculated for age, body mass index (BMI), disease duration and number of hemodialysis sessions. Independent t-test and Chi square tests were used for statistical analysis.

Results

Total number of patients was 200, out which 118 (59.3%) were male. The mean age was of 41.4 years. According to the Leeds questionnaire, dyspepsia was present in 62 (63.9%) patients. Younger patients (age 20–40 years) more frequently had dyspeptic symptoms (61.5% patients), retrosternal pain (156 patients, 78.0%), regurgitation (127 patients, 63.5%), dysphagia (67 patients, 33.5%), and nausea (142 patients, 71.0%). Patients presented with intermittent pattern of symptoms in 179 (89.5%) cases, while continuous symptoms in 6 (3.0%). Dyspepsia was associated with aspartate aminotransferase (AST) levels > 25 U/L (P = 0.001), alanine aminotransferase (ALT) levels > 28U/L (P = 0.000) and gamma glutamyl transferase (GGT) levels > 34 U/L (P = 0.002). On multivariate analysis, urea, creatinine, and presenting symptoms of dysphagia and belching showed significant statistical association with dyspepsia.

Conclusion

Dyspepsia is a common problem affecting patients with end stage renal disease and is associated with raised serum AST, ALT and GGT in such patients.

Malnutrition in Chronic Kidney Disease

Patients with chronic kidney disease are at substantial risk for malnutrition, characterized by protein energy wasting and micronutrient deficiency. Studies show a high prevalence rate of malnutrition in both children and adults with chronic kidney disease. Apart from abnormalities in growth hormone-insulin like growth factor axis, malnutrition also plays a role in the development of stunted growth, commonly observed in children with chronic kidney disease. The pathogenic mechanisms of malnutrition in chronic kidney disease are complex and involve an interplay of multiple pathophysiologic alterations including decreased appetite and nutrient intake, hormonal derangements, metabolic imbalances, inflammation, increased catabolism, and dialysis related abnormalities. Malnutrition increases the risk of morbidity, mortality and overall disease burden in these patients. The simple provision of adequate calorie and protein intake does not effectively treat malnutrition in patients with chronic kidney disease owing to the intricate and multifaceted derangements affecting nutritional status in these patients. A clear understanding of the pathophysiologic mechanisms involved in the development of malnutrition in chronic kidney disease is necessary for developing strategies and interventions that are effective, and capable of restoring normal development and mitigating negative clinical outcomes. In this article, a review of the pathophysiologic mechanisms of malnutrition in chronic kidney disease is presented.

Extracellular acidosis selectively inhibits pharmacomechanical coupling induced by carbachol in strips of rat gastric fundus

NEW FINDINGS

What is the central question of this study? Acute acidosis that results from short-term exercise is involved in delayed gastric emptying in rats and the lower responsiveness of gastric fundus strips to carbachol. Does extracellular acidosis decrease responsiveness to carbachol in tissues of sedentary rats? How? What is the main finding and its importance? Extracellular acidosis inhibits cholinergic signalling in the rat gastric fundus by selectively influencing the G_q/11 protein signalling pathway. Acute acidosis that results from short-term exercise delays gastric emptying in rats and decreases the responsiveness to carbachol in gastric fundus strips. The regulation of cytosolic Ca²⁺ concentrations appears to be a mechanism of action of acidosis. The present study investigated the way in which acidosis interferes with gastric smooth muscle contractions. Rat gastric fundus isolated strips at pH 6.0 presented a lower magnitude of carbachol-induced contractions compared with preparations at pH 7.4. This lower magnitude was absent in carbachol-stimulated duodenum and KCl-stimulated gastric fundus strips. In Ca²⁺ -free conditions, repeated contractions that were induced by carbachol progressively decreased, with no influence of extracellular pH. In fundus strips, CaCl₂ -induced contractions were lower at pH 6.0 than at pH 7.4 but only when stimulated in the combined presence of carbachol and verapamil. In contrast, verapamil-sensitive contractions that were induced by CaCl₂ in the presence of KCl did not change with pH acidification. In Ca²⁺ store-depleted preparations that were treated with thapsigargin, the contractions that were induced by extracellular Ca²⁺ restoration were smaller at pH 6.0 than at pH 7.4, but relaxation that was induced by SKF-96365 (an inhibitor of store-operated Ca²⁺ entry) was unaltered by extracellular acidification. At pH 6.0, the phospholipase C inhibitor U-73122 relaxed carbachol-induced contractions less than at pH 7.4, and this phenomenon was absent in tissue that was treated with the RhoA kinase blocker Y-27632. Thus, extracellular acidosis inhibited pharmacomechanical coupling in gastric fundus by selectively inhibiting the G_q/11 protein signalling pathway, whereas electromechanical coupling remained functionally preserved.

A pilot study of ultrasound evaluation of gastric emptying in patients with end-stage renal failure: a comparison with healthy controls

This prospective study was designed to evaluate gastric volume and content in patients with renal failure and healthy controls after an overnight fast, immediately after a light meal and at 6 h after the meal. Thirty subjects in each group were recruited. At each scanning session, gastric antral cross-sectional area was measured in the supine recumbent and right lateral decubitus positions, and a qualitative assessment of gastric contents was made using the Perlas three-point grading system. Six hours after the meal, the mean (SD) antral cross-sectional area in the supine position was 471 (195) mm² in patients with renal failure and 319 (106) mm² in healthy controls (p = 0.028), whereas in the right lateral position it was 756 (320) and 521 (180) mm² , respectively (p = 0.21). In terms of the qualitative assessments of gastric contents, all subjects had an empty stomach after an overnight fast. Five patients with renal failure and no controls had Perlas grade 2 images, indicating significant gastric contents, 6 h after a meal (p = 0.026). This study supports the use of bedside gastric ultrasound as a point-of-care test for patients with known risk factors for delayed gastric emptying.

IMI - Oral biopharmaceutics tools project - Evaluation of bottom-up PBPK prediction success part 2: An introduction to the simulation exercise and overview of results

Orally administered drugs are subject to a number of barriers impacting bioavailability (F_oral), causing challenges during drug and formulation development. Physiologically-based pharmacokinetic (PBPK) modelling can help during drug and formulation development by providing quantitative predictions through a systems approach. The performance of three available PBPK software packages (GI-Sim, Simcyp®, and GastroPlus™) were evaluated by comparing simulated and observed pharmacokinetic (PK) parameters. Since the availability of input parameters was heterogeneous and highly variable, caution is required when interpreting the results of this exercise. Additionally, this prospective simulation exercise may not be representative of prospective modelling in industry, as API information was limited to sparse details. 43 active pharmaceutical ingredients (APIs) from the OrBiTo database were selected for the exercise. Over 4000 simulation output files were generated, representing over 2550 study arm-institution-software combinations and approximately 600 human clinical study arms simulated with overlap. 84% of the simulated study arms represented administration of immediate release formulations, 11% prolonged or delayed release, and 5% intravenous (i.v.). Higher percentages of i.v. predicted area under the curve (AUC) were within two-fold of observed (52.9%) compared to per oral (p.o.) (37.2%), however, F_oral and relative AUC (F_rel) between p.o. formulations and solutions were generally well predicted (64.7% and 75.0%). Predictive performance declined progressing from i.v. to solution and immediate release tablet, indicating the compounding error with each layer of complexity. Overall performance was comparable to previous large-scale evaluations. A general overprediction of AUC was observed with average fold error (AFE) of 1.56 over all simulations. AFE ranged from 0.0361 to 64.0 across the 43 APIs, with 25 showing overpredictions. Discrepancies between software packages were observed for a few APIs, the largest being 606, 171, and 81.7-fold differences in AFE between SimCYP and GI-Sim, however average performance was relatively consistent across the three software platforms.

Volaemic status and dyspepsia in end-stage renal disease patients

AIM

Studies in animals show a relationship between extracellular volume and gastrointestinal motility. End-stage renal disease (ESRD) patients present fluid overload and frequent dyspeptic symptoms. We looked for an association between volaemic status and dyspepsia among ESRD patients undergoing haemodialysis (HD).

METHODS

We studied 155 ESRD patients on HD. Their volaemic status was evaluated using bioimpedance analysis. Fluid overload (FO) in litres and relative fluid overload (rFO) in percentage were calculated. rFO > 15% was classified as hypervolaemia. Dyspepsia was assessed through the Porto Alegre Dyspeptic Symptoms Questionnaire (PADYQ). PADYQ scores equal to or greater than 6 classified patients as dyspeptic. Characteristics of patients with and without dyspepsia were compared. Pearson's test was used to test the correlation between continuous variables. Multivariate linear and logistic regressions were performed to test FO as predictor of dyspepsia score and the presence of dyspepsia.

RESULTS

There were 64 (41.2%) patients with dyspepsia. Dyspeptics presented higher FO (2.5 ± 1.8 L vs 1.0 ± 1.8 L; P < 0.001) and higher rFO (16 ± 9.9% vs 4.8 ± 12.0%; P < 0.001). Dyspepsia score was positively correlated with FO (r = 0.300; P < 0.001) and with rFO (r = 0.256; P = 0.001). There were more patients with hypervolaemia among dyspeptics compared to non-dyspeptics (65.6% vs 17.6%; P < 0.001). FO was an independent predictor of dyspepsia score (b = 1.036; P < 0.001) and the presence of dyspepsia (OR = 2.00, 95% CI = 1.55-2.50; P < 0.001).

CONCLUSION

Hypervolaemia is associated with dyspepsia among ESRD patients on HD.

Subtotal nephrectomy inhibits the gastric emptying of liquid in awake rats

Homeostasis of blood volume (BV) is attained through a functional interaction between the cardiovascular and renal systems. The gastrointestinal tract also adjusts its permeability and motor behavior after acute BV imbalances. We evaluated the effect of progressive nephron loss on gut motility. Male Wistar rats were subjected or not (sham) to 5/6 partial nephrectomy (PNX) in two steps (0 and 7th day). After further 3, 7, or 14 days, PNX and sham operation (control) rats were instrumented to monitor mean arterial pressure (MAP), central venous pressure (CVP), heart rate (HR), and blood collection for biochemical analysis. The next day, they were gavage fed with a liquid test meal (phenol red in glucose solution), and fractional dye recovery determined 10, 20, or 30 min later. The effect of nonhypotensive hypovolemia and the role of neuroautonomic pathways on PNX-induced gastric emptying (GE) delay were also evaluated. Compared with the sham-operated group, PNX rats exhibited higher (P < 0.05) MAP and CVP values as well as increased values of gastric dye recovery, phenomenon proportional to the BV values. Gastric retention was prevented by prior hypovolemia, bilateral subdiaphragmatic vagotomy, coelic ganglionectomy + splanchnicectomy, guanethidine, or atropine pretreatment. PNX also inhibited (P < 0.05) the marker's progression through the small intestine. In anesthetized rats, PNX increased (P < 0.05) gastric volume, measured by a balloon catheter in a barostat system. In conclusion, the progressive loss of kidney function delayed the GE rate, which may contribute to gut dysmotility complaints associated with severe renal failure.