Does increasing blood pH stimulate protein synthesis in dialysis patients?

BACKGROUND: Although the mechanism of muscle wasting in end-stage renal disease is not fully understood, there is increasing evidence that acidosis induces muscle protein degradation and could therefore contribute to the loss of muscle protein stores of patients on hemodialysis, a prototypical state of chronic metabolic acidosis (CMA). Because body protein mass is controlled by the balance between synthesis and degradation, protein loss can occur as result of either increased breakdown, impaired synthesis, or both. Correction of acidosis may therefore help to maintain muscle mass and improve the health of patients with CMA. We evaluated whether alkalizing patients on hemodialysis might have a positive effect on protein synthesis and on nutritional parameters. METHODS: Eight chronic hemodialysis patients were treated daily with oral sodium bicarbonate (NaHCO(3)) supplementation for 10-14 days, yielding a pre-dialytic plasma bicarbonate concentration of 28.6 +/-1.6 mmol/l. The fractional synthesis rates (FSR) of muscle protein and albumin were obtained by the L-[(2)H(5)ring]phenylalanine flooding technique. RESULTS: Oral NaHCO(3 )supplementation induced a significant increase in serum bicarbonate (21.5 +/- 3.4 vs. 28.6 +/- 1.6 mmol/l; p = 0.018) and blood pH (7.41 vs. 7.46; p = 0.041). The FSR of muscle protein and the FSR of albumin did not change significantly (muscle protein: 2.1 +/- 0.2 vs. 2.0 +/- 0.5% per day, p = 0.39; albumin: 8.3 +/- 2.2 vs. 8.6 +/- 2.5% per day, p = 0.31). Plasma concentrations of insulin-like growth factor 1 decreased significantly (33.4 +/- 21.3 vs. 25.4 +/- 12.3 nmol/l; p = 0.028), whereas thyroid-stimulating hormone, free thyroxin and free triiodothyronine did not change significantly and nutritional parameters showed no improvement. CONCLUSION: In contrast to other findings, raising the blood pH of dialysis patients was not associated with a positive effect on albumin and muscle protein synthesis, or nutritional and endocrinal parameters.

Serumalbumin--a qualified parameter to determine the nutritional status?

OBJECTIVES: The primary objective of the study was to evaluate the relationship between serum albumin concentration and nutritional status. As a secondary objective, correlations between nutritional status, the length of hospital stay, the number of drugs taken and patients' age were assessed. METHODS: In a mono-centre non-interventional trial hospitalised patients were screened for undernutrition. Length of hospital stay, number of drug prescriptions, number of diagnoses, age and serum albumin concentration were recorded. Undernutrition was defined using the criteria of Edington et al. RESULTS: Of 232 screened patients, 102 entered the study, 52 men and 50 women with a mean age of 62.5 (SD+/-19.5) years. Twenty-nine (28.4%) patients were classified as undernourished and 73 as well-nourished. Nineteen of 25 (76%) undernourished patients showed a hypoalbuminaemia (30.5+/-6.5 g/l) compared with 74.5% (44/59) well-nourished patients (32.0+/-5.8 g/l, p 0.093). On average the length of hospital stay in undernourished patients was three days longer, which was statistically significant (p=0.009). CONCLUSIONS: Prevalence of undernutrition in the present pilot study was high and compared well with results from former studies. Serum albumin concentration could not discriminate between well and undernourished patients. Undernourished patients indicated longer length of hospital stay.

Nutritional counseling improves quality of life and nutrient intake in hospitalized undernourished patients.

OBJECTIVE: Up to 60% of hospitalized patients are undernourished. We studied the impact of nutritional therapy on quality of life and food intake. METHODS: Undernourished patients were randomized into two groups. The nutritional therapy group (NT group) received individual nutritional counseling and interventions, including oral nutritional supplements if appropriate, by a dietitian. The oral nutritional supplement group (ONS group) received oral nutritional supplements in addition to hospital meals without further instruction or counseling. Study duration was 10 to 15 d. At baseline and before discharge (time point 1) we measured energy and protein intakes and quality of life. Quality of life was measured again 2 mo after discharge (time point 2). RESULTS: Energy and protein intakes increased between baseline and time point 1 in both groups (P=0.001). The NT group (n=18) met the energy requirements at time point 1 by 107% and of protein by 94%, the ONS group (n=18) by 90% and 88%, respectively. Hospital meals alone did not cover the requirements. From baseline to time point 1, quality of life increased in both groups. Quality of life increased further in the NT group from time point 1 to time point 2 (P=0.016), but not in the ONS group. CONCLUSION: Both interventions caused a significant increase in energy and protein intakes and quality of life. In the NT group every patient received an efficacious individualized intervention. In contrast, the 7 of 18 patients in the ONS group who did not consume ONS had no intervention at all. Therefore, undernourished patients should be counseled individually by a dietitian.