Long-term use of 1.1% amino acid dialysis solution in hypoalbuminemic continuous ambulatory peritoneal dialysis patients

Better Preservation of the Peritoneum in Rats Exposed to Amino Acid-Based Peritoneal Dialysis Fluid

Background

Glucose-containing peritoneal dialysis fluids (PDF) show impaired biocompatibility, which is related partly to their high glucose content, presence of glucose degradation products, low pH, and lactate buffer, or a combination of these factors. In a rat chronic peritoneal exposure model, we compared effects of an amino acid-based PDF (AA-PDF) with a glucose-containing PDF on the peritoneal microcirculation and morphology.

Method

Two groups of rats received 10 mL of either fluid daily for 5 weeks via peritoneal catheters connected to implanted subcutaneous mini vascular access ports. Leukocyte–endothelium interactions in the mesenteric venules were investigated by intravital microscopy. Quantification of angiogenesis and fibrosis and inspection of the mesothelial cell layer were performed by light and electron microscopy.

Results

Daily exposure to glucose-containing PDF resulted in a significant increase in the number of rolling leukocytes in mesenteric venules, whereas instillation of AA-PDF did not change the level of leukocyte rolling. Glucose-containing PDF evoked a significantly higher number of milky spots in the omentum, whereas this response was significantly reduced in animals exposed to the AA-PDF ( p < 0.02). Chronic instillation of glucose-containing PDF induced angiogenesis in various peritoneal tissues, accompanied by fibrosis in the mesentery and parietal peritoneum. Quantitative morphometric evaluation of omentum and mesentery showed a clear trend toward less angiogenesis after treatment with the AA-PDF compared to the glucose-containing PDF, which reached statistical significance in the parietal peritoneum ( p < 0.04). Instillation of AA-PDF resulted in approximately 50% reduction of fibrosis in the mesentery ( p < 0.04) and approximately 25% reduction in the parietal peritoneum ( p < 0.009) compared to glucose-containing PDF. Glucose-containing PDF damaged the mesothelial cell layer, whereas the mesothelium was intact after AA-PDF treatment, as evidenced by electron microscopy.

Conclusion

Our data in a rat chronic peritoneal exposure model clearly demonstrate reduced immune activation (evidenced by decreased number of rolling leukocytes and decreased induction of omental milky spots) and reduced neoangiogenesis, fibrosis, and mesothelial damage of the peritoneal membrane after treatment with AA-PDF compared to glucose-containing PDF.

Nutrition in Older Adults on Peritoneal Dialysis

Nutrition in older adults on peritoneal dialysis is an important aspect of a patient's clinical management as well as being influenced by their overall well-being, both mental and physical. This is especially pertinent as individuals age, since the potential impact of life changes and physical changes contribute to the development of protein-energy wasting and potentially exacerbating sarcopenia and wasting. This article provides an outline of the nutritional issues to consider in older adults on peritoneal dialysis (PD).

Increasing the use of biocompatible, glucose-free peritoneal dialysis solutions

A major concern inhibiting some clinicians from embracing peritoneal dialysis (PD) as the preferred first modality of dialysis is the effects of PD solutions on the peritoneal membrane. These anatomical and functional changes predispose to complications like peritonitis, encapsulating peritoneal sclerosis and ultrafiltration failure. In recent years, “biocompatible” and glucose-sparing PD regimens have been developed to minimize damage to the peritoneal membrane. Can the use of these more expensive solutions be justified on current evidence? In this review of the literature, we explore how we may individualize the prescription of biocompatible PD fluid.

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.

A peritoneal dialysis regimen low in glucose and glucose degradation products results in increased cancer antigen 125 and peritoneal activation

BACKGROUND

Glucose and glucose degradation products (GDPs) in peritoneal dialysis fluids (PDFs) are both thought to mediate progressive peritoneal worsening.

METHODS

In a multicenter, prospective, randomized crossover study, incident continuous ambulatory peritoneal dialysis patients were treated either with conventional lactate-buffered PDF (sPD regimen) or with a regimen low in glucose and GDPs: Nutrineal×1, Extraneal×1, and Physioneal×2 (NEPP regimen; all solutions: Baxter Healthcare, Utrecht, The Netherlands). After 6 months, patients were switched to the alternative regimen for another 6 months. After 6 weeks of run-in, before the switch, and at the end of the study, 4-hour peritoneal equilibration tests were performed, and overnight effluents were analyzed for cells and biomarkers. Differences between the regimens were assessed by multivariate analysis corrected for time and regimen sequence.

RESULTS

The 45 patients who completed the study were equally distributed over both groups. During NEPP treatment, D(4)/D(0) glucose was lower (p < 0.01) and D/P creatinine was higher (p = 0.04). In NEPP overnight effluent, mesothelial cells (p < 0.0001), cancer antigen 125 (p < 0.0001), hyaluronan (p < 0.0001), leukocytes (p < 0.001), interleukins 6 (p = 0.001) and 8 (p = 0.0001), and vascular endothelial growth factor (VEGF, p < 0.0001) were increased by a factor of 2-3 compared with levels in sPD effluent. The NEPP regimen was associated with higher transport parameters, but that association disappeared after the addition of VEGF to the model. The association between NEPP and higher effluent levels of VEGF could not be attributed to glucose and GDP loads.

CONCLUSIONS

Study results indicate preservation of the mesothelium and increased peritoneal activation during NEPP treatment. Whether the increase in VEGF reflects an increase in mesothelial cell mass or whether it points to another, undesirable mechanism cannot be determined from the present study. Longitudinal studies are needed to finally evaluate the usefulness of the NEPP regimen for further clinical use.

Glucoregulatory hormones and choice of osmotic agent in peritoneal dialysis

OBJECTIVE

The present study was performed to explore the range of effects of amino acid-based peritoneal dialysis (PD) solutions on glucoregulatory hormones in comparison with an osmotically equivalent glucose-based solution. ♢

METHODS

13 adult nondiabetic patients on PD underwent 2 peritoneal dwells of 2 hours' duration with either 1.5% dextrose solution or 1.1% amino acid solution. Serial sampling for glucoregulatory hormones was done throughout the duration of the dwell. ♢

RESULTS

Instillation of the 1.5% dextrose solution resulted in a modest change in plasma glucose, paralleled by a small increase in plasma insulin levels and plasma insulin-like growth factor (IGF-1). Plasma glucagon was not changed and plasma growth hormone level declined. Instillation of the 1.1% amino acid solution resulted in an increase in plasma glucose, plasma insulin, plasma glucagon, and plasma IGF-1. Plasma growth hormone level declined. Both solutions led to an increase in plasma norepinephrine but no changes were observed in epinephrine or dopamine. ♢

CONCLUSIONS

Our observations suggest that the mere replacement of glucose by amino acids in PD solutions does not necessarily imply "glucose sparing" from the perspective of induction of a glucoregulatory hormonal response because of the aminogenic stimulation of secretion of multiple hormones.

Update on peritoneal dialysis solutions

Since the widespread introduction of peritoneal dialysis (PD) into the standard care of patients with chronic kidney disease there has been a shift from the initial focus on technique survival to refinement of the therapy to enhance biocompatibility and improve both the local peritoneal and systemic consequences of PD. One of the most significant contributions to these advances has been the development of novel PD solutions. The use of new manufacturing techniques, buffer presentation, and new osmotic alternatives to glucose have allowed potentially improved peritoneal survival (in terms of structure and function) and improved subjective patient experience. Additional benefits have also included, enhanced management of salt and water removal, supported nutritional status and improvement in the systemic metabolic derangements associated with conventional PD treatment, based on glucose-containing lactate-buffered solutions. The selection of suitable targets for modulation of therapy continues to be hampered by our continued relative ignorance of the local and particularly systemic effects of PD compounded by the dearth of quality, outcome-based studies. The aim of this review is to summarize the characteristics of the next generation of PD fluids currently available, and then to evaluate their possible place in treatment by considering the difference in their effects in a series of structural and functional areas potentially relevant to improving patient outcomes.

Asaia bogorensis peritonitis identified by 16S ribosomal RNA sequence analysis in a patient receiving peritoneal dialysis

Here the authors report a case of refractory peritonitis leading to multiple hospitalizations and the loss of peritoneal dialysis access in a patient on automated peritoneal dialysis, caused by Asaia bogorensis, a bacterium not previously described as a human pathogen. This organism was identified by sequence analysis of the 16S ribosomal RNA gene. Unusual microbial agents may cause peritonitis, and molecular microbiological techniques are important tools for identifying these agents.

Protein and energy nutrition among adult patients treated with chronic peritoneal dialysis

Protein-energy malnutrition (PEM) in adult patients treated with chronic peritoneal dialysis (CPD), which is highly prevalent and frequently severe in its manifestation, poses a significant therapeutic dilemma. The causes of PEM include inflammation, low nutrient intake, nutrient losses during dialysis, metabolic acidemia, coexisting illnesses, and possibly the endocrine disorders of uremia. Treatment strategies for PEM in CPD patients include the following: attempt to treat the potentially reversible causes of anorexia, increase nutrient intake (by nutritional counseling, oral food supplements, consideration of appetite stimulants and intraperitonial amino acid solutions), and the correction of metabolic acidosis. Coexisting illnesses engendering PEM should be treated. Experimental evidence suggests that such agents as anabolic steroids, human growth hormone, insulin-like growth factor-I, and L-carnitine may engender positive protein balance in these individuals. Finally, the use of anti-inflammatory agents to improve the nutritional status of malnourished CPD patients remains to be defined. There is a need to carry out clinical trials that examine whether an improvement in the nutritional status of CPD patients is associated with an improvement in their mortality, morbidity and/or quality of life.