Serum Sphingosine-1-phosphate level and peritonitis in peritoneal dialysis patients

BACKGROUND

Given the important role of Sphingosine-1-phosphate (S1P) in maintaining the hemostasis in intestinal barrier function and regulation of inflammation and immune, we hypothesize that S1P might be a biomarker to predict peritonitis in peritoneal dialysis (PD) patients.

METHODS

In this case-control study, 78 stable, continuous ambulatory peritoneal dialysis patients were enrolled and followed for the episode of PD associated peritonitis. Patients were divided into two groups by whether or not they had peritonitis during follow-up: non-peritonitis (n = 65) and peritonitis (n = 13) group. S1P was analyzed by enzyme-linked immunosorbent assay. Logistic regression analysis was used to assess factors associated with peritonitis. The variables identified by univariable regression models (p < 0.1) were further selected into the multivariable logistic regression model to determine whether they could independently affect peritonitis.

RESULTS

Patients with peritonitis had a lower level of S1P than that of patients without peritonitis (1.3 ng/mL IQ 0.8, 3.6 ng/mL vs. 2.8 ng/mL IQ 1.5, 5.4 ng/mL, p = 0.018). The peritonitis group had lower serum albumin, lower blood leukocyte, lower hemoglobin and lower platelet count as compared to the non-peritonitis group. Logistic regression analysis showed that S1P (OR = 0.381, 95% CI = 0.171-0.848, p = 0.018), blood leukocyte count (OR = 0.438, 95% CI = 0.207-0.925, p = 0.030), and serum albumin (OR = 0.732, 95% CI = 0.556-0.962, p = 0.025) were independent factors associated with peritonitis in the present PD population.

CONCLUSION

Our study showed that S1P was an independent determinant of subsequent peritonitis in PD patients. S1P might serve as a biomarker to predict peritonitis in PD patients.

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.

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.

Diminished appetite predicts mortality of Chinese peritoneal dialysis patients

BACKGROUND

Many maintenance dialysis patients experience a common cluster of symptoms, including diminished appetite (anorexia). This symptom has been associated with reduced quality of life and increased mortality in this population.

AIM

The aim of this study was to determine whether diminished appetite is a significant predictor of negative clinical outcomes in patients on peritoneal dialysis (PD).

METHOD

A longitudinal prospective study was conducted in 98 patients receiving PD in Beijing, China. Clinical characteristics, nutritional and inflammatory marker levels, and related peritoneal treatment information were collected. The appetite status and serum albumin levels were assessed initially and reevaluated monthly during the first year of follow-up. All patients were followed for nearly 5 years or until death. Data were collected about mortality, hospitalization, and peritonitis.

RESULTS

The mean age of participants was 60.3 ± 14.4, and 22.8% reported diminished appetite. At baseline, female sex, cardiovascular disease, and prealbumin level were the significant predictors of appetite. The average length of follow-up was 39 (range: 2-57) months. The Kaplan-Meier survival curve showed the survival rate was lower in patients reporting diminished appetite than for patients reporting normal appetite. Multivariate analysis indicated that diminished appetite, diabetes, ferritin, and serum albumin levels were independent predictors of mortality.

CONCLUSION

Self-reported appetite was a predictor of clinical characteristics and outcome for patients receiving PD. Conducting appetite evaluation periodically is recommended as a nursing strategy to improve care for these patients.

Nutrition and the kidney: recommendations for peritoneal dialysis

Protein energy wasting (PEW) is highly prevalent in peritoneal dialysis (PD) and is associated with poor outcomes, including hospitalization and mortality. Recognizing and diagnosing PEW in PD is important; although studies are limited, there are interventions that may be associated with improved outcomes. In this review of nutritional aspects of PD, we highlight some of the important causes of PEW and explore the current diagnostic tools that are used to assess PEW. Finally, we discuss the established and experimental therapies for PEW in PD.

Nutrition in infants and very young children with chronic kidney disease

Provision of adequate nutrition is a cornerstone of the management of infants and very young children with chronic kidney disease (CKD). Very young children with CKD frequently have poor spontaneous nutritional intake. Because growth depends strongly on nutrition during early childhood, growth in very young children with CKD is often suboptimal. In this review we will consider the mechanisms and manifestations of inadequate nutritional status in very young children with CKD, mechanisms mediating inadequate nutritional intake, and the optimal nutritional management of this special population. In addition, we suggest an approach to the assessment of nutritional status, including the use of body mass index in infants. Five major nutritional components are considered: energy, macronutrients, fluids and electrolytes, micronutrients, and calcium/phosphorus/vitamin D. The use of adjunctive therapies, including appetite stimulants, treatment of gastroesophageal reflux and gastric dysmotility, enhanced dialytic clearance, and growth hormone, is also briefly discussed.

Peritoneal dialysis patients have higher prevalence of gastrointestinal symptoms than hemodialysis patients

OBJECTIVE

Malnutrition is common in dialysis patients and is attributed to decreased food intake, and/or chronic systemic inflammation linked to dialysis-related comorbidities and complications. This study aimed to determine the prevalence of gastrointestinal (GI) symptoms in dialysis patients and whether this impacts food intake.

DESIGN

Cross-sectional study.

SETTING

Tertiary teaching hospital.

PARTICIPANTS

All consenting hospital peritoneal dialysis (PD) and hemodialysis (HD) patients.

METHODS

Patients were interviewed by a dietitian regarding the prevalence and impact of GI symptoms (nausea, vomiting, bloating, early satiety, diarrhea, heartburn, fatigue, and weight changes). Serum levels of albumin were measured, and the use of medication known to cause GI symptoms was recorded.

MAIN OUTCOME MEASURE

Presence of GI symptoms.

RESULTS

The PD (n = 122) and HD (n = 172) groups were similar in age, gender, and presence of diabetes. Serum albumin levels were lower for those on PD compared with HD (3.2 vs. 3.5 g/dL, P < .001). Eighty-five percent of the patients on PD reported at least 1 GI symptom, compared with 51% on HD. Compared with HD, more PD patients reported that GI symptoms were related to the onset of dialysis (55% vs. 12%, P < .001). A greater number of PD patients (compared with HD patients) reported a decrease in food intake (53% vs. 14%, P < .001) and that they had attempted dietary changes to alleviate symptoms (34% vs. 9%, P < .001).

CONCLUSION

These results should influence dietetic educational practice. In addition to the provision of adequate protein and energy, dialysis patients should be counselled regarding the management of GI symptoms and monitored for the prevalence and severity of these symptoms.

Nutrition in patients on peritoneal dialysis

Protein-energy wasting (PEW) is prevalent among patients on dialysis and has emerged as an important risk factor for morbidity and mortality in these patients. Numerous factors, including inflammation, inadequate dialysis, insufficient nutrient intake, loss of protein during dialysis, chronic acidosis, hypercatabolic illness and comorbid conditions, are involved in the development of PEW. The causes and clinical features of PEW in patients on peritoneal dialysis and hemodialysis are comparable; assessment of the factors that lead to PEW in patients receiving peritoneal dialysis is important to ensure that PEW is managed correctly in these patients. For the past 20 years, much progress has been made in the prevention and treatment of PEW. However, the results of most nutritional intervention studies are inconclusive. In addition, the multifactorial and complicated pathogenesis of PEW makes it difficult to assess and treat. This Review summarizes the nutritional issues regarding the causes, assessment and treatment of PEW, with a focus on patients receiving peritoneal dialysis. In addition, an in-depth overview of the results of nutritional intervention studies is provided.

Effects of chronic renal failure on gastrointestinal motility: a study on the changes of gastric emptying, small intestinal transit, interdigestive myoelectric complex, and fecal water content

BACKGROUND

Gastrointestinal (GI) dysfunction may lead to malnutrition in patients with chronic renal failure (CRF). This study investigated the effects of CRF on GI motility.

METHODS

Forty-eight Sprague Dawley rats (180 ± 20 g) were randomly classified into CRF group and sham-operated (Sham) group, and each group was further assigned for gastric emptying (GE), small intestinal transit (SIT), interdigestive myoelectric complex (IMC), and fecal water content (FWC) experiments (6 CRF and 6 Sham rats per experiment). The CRF model was established by 5/6 nephrectomy. The body weight (BT), GE, SIT, IMC, and FWC of the rats were observed. ANOVA and Student-Newman-Keuls q-test were utilized to do statistical analysis.

RESULTS

The BT of the rats in the two groups had no statistical difference before surgery. But in the ninth week after surgery, the CRF rats (230 ± 20 g) weighed less than the Sham rats (260 ± 15 g) (p < 0.05). The GE rate and SIT rate in CRF rats were significantly lower than that of Sham rats (GE 33.08 ± 7.50 vs. 53.37 ± 9.78%; SIT 42.92 ± 8.96 vs. 58.67 ± 9.12%) (p < 0.05). Compared with the IMC of the Sham rats, the CRF rats showed obvious alterations in (a) IMC cycle; (b) phase II and phase III duration; and (c) phase III cycling frequency, amplitude, and percentage (p < 0.05). FWC of the CRF rats increased significantly (p < 0.05).

CONCLUSION

The GI motility of the CRF rats is obviously impaired. This finding may indicate that the effects of CRF on GI motility might be relatively prevalent.

Appetite and gastrointestinal symptoms in chronic hemodialysis patients

OBJECTIVE

The aim of the present cross-sectional study was to assess the association between self-reported appetite and gastrointestinal symptoms in chronic hemodialysis patients.

DESIGN

A cross-sectional study was carried out.

SETTING

The study was carried out at an outpatient hemodialysis service center.

PATIENTS

A total of 110 patients were included in this study.

INTERVENTION

The first question of the Hemodialysis Study Appetite questionnaire was used to assess the appetite of the HD patients. The multiple-choice answers for the first question "During the past week, how would you rate your appetite?" were as follows: (1) very good, (2) good, (3) fair, (4) poor, or (5) very poor. At the same time, each patient was invited to answer the following questions: Did you have any of the following symptoms (hiccups, feeling full after a few bites of food, nausea, vomiting, indigestion, abdominal pain, bloating, and constipation) in the last 2 weeks? Are there particular foods that you used to like but now do not? Did you have changes in smell in the last 2 weeks? Did you have taste changes in the last 2 weeks?

MAIN OUTCOME MEASURE

Possible associations between appetite and gastrointestinal symptoms were assessed in this study.

RESULTS

In 52 (47.2%) HD patients, the appetite was very good or good (group A), in 28 (25.4%) fair (group B), and in 30 (27.3) poor or very poor (group C). The most frequent symptoms were bloating and constipation. The frequency of food aversion and early satiety were 23.6% and 18.2%, respectively. The frequency of changes in smell and taste were 3.6% and 7.2%, respectively. The frequency of early satiety, food aversion, changes in smell and taste was significantly higher in group C as compared with group A. Similarly, the frequency of early satiety, food aversion, and changes in taste were higher in group B than in group A. The other frequencies did not differ significantly among group A, B, and C.

CONCLUSION

Food aversion, early satiety, changes in taste and smell were significantly more frequent in HD patients with poor or very poor appetite as compared with those with good or very good appetite.

Intestinal bacterial overgrowth in CAPD patients with hypokalaemia

OBJECTIVE

We have previously demonstrated that hypokalaemia is a risk factor for enteric peritonitis in CAPD patients. The underlying mechanism is unclear, and there have been no similar reports. We hypothesized that hypokalaemia may result in dysmotility of the intestinal tract and in turn cause bacterial overgrowth and subclinical translocation of enteral bacteria.

METHODS

Uraemic patients undergoing CAPD in our hospital were enrolled in the study. Hypokalaemia was defined as a serum potassium (K) level < or = 3.5 mEq/L despite treatment for 1 month. A breath hydrogen test (BHT) was performed to detect if intestinal bacterial overgrowth was present. Blood samples were also collected for the study of inflammatory cytokines, including interleukin 1 (IL1), IL2, IL6, IL8, TNF-alpha and gamma-IFN.

RESULTS

A total of 68 patients were recruited. Hypokalaemia was present in 18 cases (26.5%, group 1), while 50 cases (group 2) had normal serum K levels. A higher prevalence of abnormal BHT was found in group 1 (27.8%), compared with group 2 (8.0%, P = 0.048). There was a trend towards a higher prevalence of abnormal BHT in diabetes mellitus (DM) patients with hypokalaemia (80.0%) compared with normal kalaemia (22.2%, P = 0.09), while no similar trends were found in non-DM hypokalaemic patients (7.7 versus 4.9%). When comparisons were made among different subgroups, patients with DM and hypokalaemia had a significantly higher prevalence of abnormal BHT compared to non-DM, normokalaemic patients (P < 0.0004) and non-DM, hypokalaemic patients (P = 0.008). Multivariate logistic regression analysis revealed that DM was an independent risk factor for abnormal BHT (odds ratio: 12.39, 95% CI: 2.25-68.20, P = 0.004). There was no significant difference in serum albumin, Kt/V, weekly creatinine clearance, pattern of peritoneal equilibrium test, C-reactive protein and various inflammatory cytokines between the two groups.

CONCLUSION

CAPD patients with hypokalaemia may have intestinal bacterial overgrowth. While both DM and hypokalaemia might contribute to this abnormality, only DM appeared to be the independent risk factor.

Effect of chronic renal failure on foregut smooth muscle reactivity: an experimental study

PURPOSE

An association between chronic renal failure (CRF) and gastroesophageal reflux (GER) is well known. The aim of this study was to pharmacologically characterize and investigate the possible contribution of smooth muscle reactivity pathways involving GER on the CRF rat model.

MATERIAL AND METHODS

Chronic renal failure was created in Sprague-Dawley rats by 5 of 6 nephrectomy. The rats were divided into 2 groups: the CRF-induced group (CRF group) and the sham-operated group (control group). Esophageal smooth muscle strips were studied in vitro for their contractile (KCl, carbachol) and relaxant (isoproterenol, serotonin, and papaverine) response to receptor activation in the organ chambers set up. Subsequently, the in vitro lower esophageal sphincter (LES) smooth muscle study was generated by KCl, carbachol, isoproterenol, nicotine, sodium nitroprusside (SNP), and papaverine.

RESULTS

Compared with controls, esophageal strips taken from CRF-induced rats associated with decreased smooth muscle responses to carbachol, serotonin, and increased response to KCl. Isoproterenol- and papaverine-induced relaxant responses were not affected. Contractility of the isolated LES strips were significantly increased to KCl and carbachol in the CRF group compared with the control group. Similar relaxant responses were obtained in LES strips stimulated by isoproterenol, SNP, and papaverine in the CRF and control group. Nicotine-induced relaxant responses were decreased in the CRF group compared with the control group.

CONCLUSIONS

Our study revealed alterations of receptor-dependent esophageal and LES smooth muscle reactivity in the CRF-induced rats. Impaired foregut smooth muscle reactivity may contribute to the development of GER-related functional abnormalities in patients with CRF.

Impairment of small intestinal protein assimilation in patients with end-stage renal disease: extending the malnutrition-inflammation-atherosclerosis concept

BACKGROUND

Protein malnutrition is a common finding in renal disease. Recently, we showed that impaired protein assimilation (digestion and absorption) may contribute to protein malnutrition in nondiabetic patients with chronic renal failure.

OBJECTIVE

The aim of the present study was to evaluate whether these findings can be extended to the dialysis population. Moreover, relations with indexes of the malnutrition-inflammation-atherosclerosis (MIA) syndrome were investigated.

DESIGN

Protein assimilation was evaluated in 24 healthy control subjects and in 40 patients with end-stage renal disease (ESRD; 14 treated with peritoneal dialysis and 26 with hemodialysis) by means of a [13C]protein breath test, quantification of the generation rate of p-cresol, or both methods. Both approaches provide reliable information on the efficiency of protein assimilation. Breath test results were expressed as the maximum percentage recovery per hour of the administered dose of 13C (%max) and as the cumulative percentage recovery at the end of the test (%cum end). Several indexes of nutritional status, inflammation, and atherosclerosis were assessed.

RESULTS

Compared with the control subjects, ESRD patients had significantly lower breath-test derived indexes of protein assimilation [%max=3.75 +/- 0.30 compared with 4.90 +/- 0.25, P=0.006; %cum end=12.41 (5.74-23.22) compared with 16.87 (9.42-22.99), P=0.020] and a higher 24-h p-cresol generation rate corrected for dietary protein intake [3.89 (0.48-11.60) compared with 2.81 (0.21-11.20) mg p-cresol/g urea nitrogen; P=0.028]. The presence of impaired protein assimilation was associated with indexes of the MIA syndrome.

CONCLUSION

Our study provides evidence that protein assimilation is impaired in ESRD patients. Moreover, this disorder is associated with the severity of the MIA syndrome.