Peritoneal Protein Losses and Cytokine Generation in Automated Peritoneal Dialysis with Combined Amino Acids and Glucose Solutions

Abstract

Objectives. Protein-energy malnutrition as a consequence of deficient protein intake frequently occurs in peritoneal dialysis (PD) patients. Previously, we showed that peritoneal dialysate containing a mixture of amino acids (AA) and glucose has anabolic effects. However AA-dialysate has been reported to increase intraperitoneal protein and AA losses and the release of proinflammatory cytokines (interleukine-6 (IL-6) and tumor necrosis factor alpha (TNFα)). We investigated the effect of AA plus glucose (AAG) solutions on peritoneal protein losses and cytokine generation. Methods. In 6 patients on standard automated peritoneal dialysis (APD) 12 APD sessions of 6 cycles each were performed during the night using dialysate containing 1.1% AA plus glucose or glucose alone as control. Protein losses and TNFα and IL-6 concentrations were measured in dialysates separately collected from nightly cycling and daytime dwell. Results. The 24 hour-protein losses with AAG (median 6.7 g, range 4.7–9.4 g) were similar to control dialysate (median 6.0 g, range 4.2–9.2 g). Daytime dialysate IL-6 levels were higher after nightly AAG dialysis than after control dialysis (142 pg/ml and 82 pg/ml, respectively, P<.05). TNFα concentrations were very low. Conclusion. Nightly APD with amino acids containing dialysate was associated with an increase in peritoneal IL-6 generation during the day. The addition of AA to standard glucose dialysis solutions did not induce a significant increase of peritoneal protein losses.

Comparison of Intraperitoneal Amino Acid and Oral Amino Acid Supplements in Peritoneal Dialysis Patients

“…Some studies have suggested that dialysates combining dextrose and amino acids are a better choice to maintain muscle mass in patients with lower nutritional intake levels [44]. On the other hand, mixtures of AA plus glucose as a source of proteins have been shown to have almost the same effect with glucose only solutions in controlling protein loss [6].…”

“…In addition, a study by Boudville et al demonstrated that oral supplements, when taken before eating food, could improve caloric and protein intakes of PD patients significantly [54]. In their study investigating the effects of oral protein supplements in PD patients, Moretti et al found that protein supplement group had significantly improved levels of nPCR and albumin, but these levels declined after the patients discontinued the supplements [6].…”

“…Identified by the International Society for Renal Nutrition and Metabolism in 2008, the diagnostic criteria for of protein-energy wasting are classified into 4 categories of abnormalities: 1) abnormal serum biochemistry, 2) reduced body mass, 3) reduced muscle mass, and 4) unintentional low dietary intakes [1]. In the development of PEM, various factors might play a role, which includes acidosis, insulin resistance and uremic toxins, inflammation, inadequate dialysis, hypercatabolic critical illness, protein and amino acid loss, insufficient protein and calorie intake [2][3][4][5][6]. In routine monitoring of patients with end-stage renal disease, the most prevalent instrument is the measurement for biochemical value of serum albumin level, where both lower intakes of certain nutrients and systemic inflammation are commonly associated with protein-energy wasting among dialysis dependent renal failure patients, which may lead to hypoalbuminemia [7,8].…”

“…However in reality, studies show that patient often fail to achieve such levels of protein and energy levels, with reported daily intakes of less than 1.0 g/kg and 26 kcal/kg [11]. Amino acid losses into dialysate during continuous ambulatory peritoneal dialysis (CAPD) range from 2 to 4 g, while 5-15 grams of proteins such as albumin, immunoglobulin, complement, transferrin, ß 2 -microglobulin, and α 2 -macroglobulin are lost [12][13][14] during a 24-hour collection period [5,6].…”

Solutions for peritoneal dialysis in children: recommendations by the European Pediatric Dialysis Working Group

“…Experimental studies, however, do not unequivocally support the notion of improved biocompatibility [55,87]. Amino acids induce mesothelial nitric oxide production, a factor involved in neoangiogenesis [88]; increase effluent IL-6 concentrations, a potential surrogate marker of inflammation [89]; and suppress leukocyte recruitment in rats [54]. Long-term dialysis in rats, however, revealed only minor peritoneal changes and preserved ultrafiltration capacity, similar to double-chamber PD fluid [55].…”