Does glucose present in the dialysate limit oxidative stress in patients undergoing regular hemodialysis?

Haemodialysis-induced hypoglycaemia and glycaemic disarrays

In patients with diabetes receiving chronic haemodialysis, both very high and low glucose levels are associated with poor outcomes, including mortality. Conditions that are associated with an increased risk of hypoglycaemia in these patients include decreased gluconeogenesis in the remnant kidneys, deranged metabolic pathways, inadequate nutrition, decreased insulin clearance, glucose loss to the dialysate and diffusion of glucose into erythrocytes during haemodialysis. Haemodialysis-induced hypoglycaemia is common during treatments with glucose-free dialysate, which engenders a catabolic status similar to fasting; this state can also occur with 5.55 mmol/l glucose-containing dialysate. Haemodialysis-induced hypoglycaemia occurs more frequently in patients with diabetes than in those without. Insulin therapy and oral hypoglycaemic agents should, therefore, be used with caution in patients on dialysis. Several hours after completion of haemodialysis treatment a paradoxical rebound hyperglycaemia may occur via a similar mechanism as the Somogyi effect, together with insulin resistance. Appropriate glycaemic control tailored for patients on haemodialysis is needed to avoid haemodialysis-induced hypoglycaemia and other glycaemic disarrays. In this Review we summarize the pathophysiology and current management of glycaemic disarrays in patients on haemodialysis.

Impact of constant storage temperatures and multiple warming cycles on the quality of stored red blood cells

BACKGROUND

Red blood cells (RBCs) are routinely stored in liquid state at temperatures below 6°C, and RBC unit core temperature should not exceed 10°C during transport. Since the critical temperature of 10°C was chosen mostly arbitrarily, this study investigated the effect of both constant temperature settings as well as multiple rewarming cycles on stored RBCs with respect to morphology, biochemical parameters and haemolysis.

MATERIALS AND METHODS

Buffy coat-depleted filtered RBCs were used as standard products. RBCs were stored at 1-6°C (reference group, n = 12), 13 and 22°C (test groups, n = 12 each) or stored at 1-6°C and warmed up five times to 10, 13, or 22°C for a period of 24 h each. Various biochemical parameters were measured weekly. RBCs were further investigated using electron microscopy.

RESULTS

Red blood cells stored constantly at 13 or 22°C showed stable haemolysis rates until day 28 and day 14, respectively. RBCs stored at 1-6°C with five warming-up periods to 10, 13 or 22°C each lasting 24 h (total 120 h) did not exceed the limit of the haemolysis rate at the end of storage. Differently shaped erythrocytes were found in all samples, but more crenate erythrocytes appeared after 42 days of storage independent of temperature profiles.

CONCLUSION

Red cells can be kept at constant temperatures above 6°C without apparent harmful effects at least until day 14, whereas multiple warming cycles for no longer than 24 h at 10, 13 or 22°C with subsequent cooling do not cause quality loss as assessed using the in vitro assays employed in this study.

Does glucose in dialysis fluid protect erythrocytes in patients with chronic renal failure?

BACKGROUND/AIMS

The aim of this study was to assess the multifaceted influence of glucose present in dialyzing fluid on erythrocytes of patients with chronic renal failure (CRF) undergoing regular hemodialysis.

METHODS

A group of 44 subjects with CRF undergoing regular hemodialysis was studied. Two tests were used: osmotic fragility and resistance to the hemolytic agent saponin. The total content of isoprostane 8-iso-prostaglandin F2alpha type III (8-iPF2alpha-III) in plasma and erythrocyte's membrane were determined by the ELISA method.

RESULTS

The presence of glucose in the dialysate is associated with lower intravascular hemolysis markers and high total 8-iPF2alpha-III concentrations in plasma.

CONCLUSION

The presence of glucose in dialyzing fluid could protect erythrocytes. It limits hemolysis in patients with CRF, but, on the other hand, increases the oxidative processes. This kind of treatment along with other therapeutic intervention such as administration of antioxidants (e.g. alpha-tocopherol, ascorbic acid, N-acetylcysteine) could improve the condition of erythrocytes and outcome in CRF.

Influence of Glucose in the Dialysate on the Activity of Erythrocyte-Glutathione-Peroxidase and Blood Selenium Concentration in Hemodialyzed Patients

BACKGROUND

The aim of the study was to show the influence of glucose in the dialysate on the intensity of oxidative stress, activity of glutathione peroxidase (GSHPx) and concentration of selenium in patients undergoing regular hemodialysis.

METHODS

The study was comprised of 85 patients hemodialyzed with dialysate containing glucose [HD-g(+)] or not containing glucose [HD-g(-)], patients with chronic renal failure on conservative treatment and control group. The concentrations of the products of reaction with thiobarbituric acid (TBARS), concentration of selenium in erythrocytes and plasma, concentration of copper in erythrocytes and the activity of GSHPx were determined.

RESULTS

GSHPx had significantly higher activity in HD-g(-) group before HD than in control group. In HD-g(+) group before hemodialysis, the activity of GSHPx was significantly lower than in the control group. After HD, the activity showed a statistically significant increase. In both hemodialyzed groups, selenium concentration before hemodialysis both in plasma and erythrocytes was significantly lower, compared to control group. In the group of patients with CRF on conservative treatment, selenium concentration in RBC was significantly higher, compared to concentrations obtained in other groups except for control group. The increase of copper concentration in erythrocytes was accompanied by the increase of oxidative stress and increase of TBARS concentration. The opposite relationship was observed for selenium-its concentration was inversely correlated to copper concentration.

CONCLUSIONS

In both groups of hemodialyzed patients, hemodialysis caused the increase of GSHPx in erythrocyte activity and increase of plasma and erythrocyte selenium concentration.

The effect of glucose added to the dialysis fluid on blood pressure, blood glucose, and quality of life in hemodialysis patients: a placebo-controlled crossover study

BACKGROUND

Risk for hypoglycemia increases during hemodialysis sessions. The compensatory homeostatic response to hypoglycemia may increase the risk for abnormal blood pressure regulation. The purpose is to determine blood pressure and blood glucose levels and variability in these variables during dialysis with and without glucose in the dialysis fluid.

METHODS

In a randomized, placebo-controlled, unblinded, crossover study of 44 hemodialysis patients, 34 patients without diabetes and 10 patients with diabetes were allocated to treatment with and without glucose in the dialysis fluid during two 10-week periods. Blood pressure and blood glucose levels were determined 5 to 8 times at each dialysis session during both periods. Quality of life was estimated by using the 36-Item Short-Form Health Survey questionnaire at the end of both treatment periods.

RESULTS

With glucose in the dialysis fluid, blood pressure was significantly lower (systolic, 144 +/- 20 versus 149 +/- 21 mm Hg; P < 0.003; diastolic, 73 +/- 10 versus 76 +/- 10 mm Hg; P < 0.001), blood glucose level was higher (125 +/- 25 versus 110 +/- 26 mg/dL [6.96 +/- 1.36 versus 6.08 +/- 1.47 mmol/L]; P < 0.001), and quality of life was the same. Variations in systolic and diastolic blood pressures and blood glucose levels were the same during both treatments. In the subgroup of patients with diabetes, variation in blood glucose levels decreased significantly with glucose in the dialysis fluid (mean, 30 versus 37 mg/dL [1.66 versus 2.03 mmol/L]; P = 0.008).

CONCLUSION

Systolic and diastolic blood pressures decreased with glucose in the dialysis fluid in patients with chronic renal failure, presumably because of insulin-induced vasodilatation in patients without diabetes. Blood glucose level regulation improved in the diabetic subgroup, and blood glucose levels were not greater in patients with diabetes with glucose in the dialysis water. Quality of life was not changed.