The Biology of the Mesothelium during Peritoneal Dialysis

Substantial derangements of mesothelial biology are observed during experimental simulations of dialysis conditions, inferred from the content of human dialysis effluent and visualized by microscopy of human mesothelial biopsies. Canosmotically active solutions be made biocompatible with the osmoregulatory system of the mesothelium? Can the contributions of the mesothelium to host defenses against inflammation and/or infection be supported during CAPD? Do underlying metabolic derangements present in various kidney diseases and end-stage renal disease, regardless of cause, require customized CAPD protocols and solutions? Use of dialysis solutions less directly toxic to the mesothelium is a necessary step toward some day manipulating peritoneal biology by pharmacological and therapeutic modalities.

Choline supply of preterm infants: assessment of dietary intake and pathophysiological considerations

BACKGROUND

Choline forms the head group of phosphatidylcholines, comprising 40-50 % of cellular membranes and 70-95 % of phospholipids in surfactant, bile, and lipoproteins. Moreover, choline serves as the precursor of acetylcholine and is important for brain differentiation and function. While accepted as essential for fetal and neonatal development, its role in preterm infant nutrition has not yet gained much attention.

METHODS

The adequate intake of choline of preterm infants was estimated from international recommendations for infants, children, and adults. Choline intake relative to other nutrients was determined retrospectively in all inborn infants below 1,000 g (extremely low birth weight) or below 28 weeks gestational age, admitted to our department in 2006 and 2007 (N = 93).

RESULTS

Estimation of adequate intake showed that children with 290 g body weight need more choline than those with 1,200 g (31.4 and 25.2 mg/kg/day, respectively). Day-by-day variability was high for all nutrient intakes including choline. In contrast to the continuous intrauterine choline delivery, median supply reached a plateau at d11 (21.7 mg/kg/day; 25th/75th percentile: 19.6; 23.9). Individual choline supply at d0-d1 and d2-d3 was <10 mg/kg/day in 100 and 69 % of infants, respectively. Furthermore, intakes <10 mg/kg/day were frequently observed beyond day 11. Median adequate intakes (27.4 mg/kg/day at 735 g body weight) were achieved in <2 %.

CONCLUSIONS

Nutritional intake of choline in this cohort of preterm infants was frequently less than the estimated adequate intake, with particular shortage until postnatal d10. Because choline is important for brain development, future studies are needed to investigate the effects of adequate nutritional choline intake on long-term neurodevelopment in VLBW infants.

Free choline and phospholipid-bound choline concentrations in serum and dialysate during peritoneal dialysis in children and adults

OBJECTIVES

This study tested whether continuous ambulatory peritoneal dialysis (CAPD) changes free or phospholipid-bound choline concentrations in serum or peritoneal dialysis fluid of patients with end stage renal disease (ESRD).

DESIGN AND METHODS

Serum and dialysate choline and phospholipid-bound choline were measured before, during and after 6 h CAPD.

RESULTS

Serum choline concentrations were higher in patients with ESRD compared with age-matched controls. CAPD lowered serum choline concentrations significantly although it did not influence phospholipid-bound choline. Choline accumulated in the dialysate, reaching 28.4 +/- 2.7 microM in children and 18.2 +/- 1.4 microM in adults, during six hours CAPD; phospholipid-bound choline increased to 22.9 +/- 2.5 microM and 10.8 +/- 1.4 microM in children and adults, respectively. The total daily loss of choline into the dialysate was 181 +/- 20 micromoles in children and 260 +/- 18 micromoles in adults.

CONCLUSION

CAPD causes a substantial loss of choline into peritoneal dialysates and reduces serum choline concentrations significantly.