v124

Dialysis – nutrition, malnutrition, oxidative stress, inflammation 1

Sunday, June 5, 2005

in platelet activity at lower temperatures was suggested from studies in cardiopulmonary bypass surgery. Therefore, in the present study, blood pressure (BP) and platelet activation were measured during HD with cool (35 °C, [HD35 ]) and normal (37 °C, [HD37 ]) dialysate temperature. Study design: Ten stable chronic HD patients were studied during HD35 and HD37 in a randomized, cross-over fashion. BP was measured every 15 minutes during three consecutive HD sessions on each modality. Blood samples were taken from both the afferent and efferent line at t0 , t5 , t30 , t60 and t150 . Platelet activation, degranulation, aggregation and serotonin release were studied by measuring platelet CD62p expression, platelet factor 4 (PF4), platelet aggregates (number/250 platelets) and platelet serotonin content, respectively. Results: Mean BP was higher during HD35 than during HD37 . Moreover less hypotensive episodes were found (Table 1).

4 (PF4), platelet aggregates (number/250 platelets) and platelet serotonin content, respectively. Results: As expected, maximal platelet activation (CD62p) occurred within 30 minutes after the start of HD. Similarly, a rise in PF4 concentration was found early in HD, with a maximum at t5 . Considering platelet aggregate formation, a small increase in the number of aggregated platelets was observed at t5 , with more manifest aggregation at t30 . As for the contribution of the various components of the ECC on platelet behaviour, gradual increments in both CD62p expression and PF4 were observed within the ECC, both after the pump and dialyser. An increment in aggregate formation on the other hand, was only seen after the pump, with a decrement after passage through the dialyser.

Table 1

t0 t5 (1) t5 (2) t5 (3) t30 (1) t30 (2) t30 (3) t60 t150

mean BP (mm Hg) hypotensive episodes

HD37

HD35

118/74 9/30 HD sessions

133/80° 3/30 HD sessions

°p < 0.01vs. HD37

Interestingly, comparing HD35 with HD37 , at t60 the degree of platelet activation, platelet degranulation and platelet aggregation was most pronounced during HD35 (Table 2). Table 2 CD62p (% platelets) HD37 HD35 t0 t5 t30 t60 t150

19 (15-27) 43 (22-66) 48 (22-80) 30 (15-80) 21 (13-64)

22 (10-29) 50 (15-68) 60 (21-81) 61 (24-85)* 33 (7-86)

PF4 (IU/ml) HD37 HD35 7 (5-16) 96 (78-136) 69 (19-129) 37 (16-92) 17 (8-95)

aggr (/250 platelets) HD37 HD35

10 (7-85) 93 (70-126) 43 (7-99) 61 (31-90) 35 (12-126)*

7 (2-18) 14 (4-22) 11 (0-27) 16 (5-22)

7 (2-23) 11(0-20) 14 (7-48) 23 (9-38)°

CD62p (% platelets)

PF4 (IU/ml)

aggr. (/250 platelets)

19 (15-27) 26 (16-56)* 29 (14-53)* 43 (22-66)*° 28 (14-57)* 42 (17-71)*° 48 (22-80)*° 30 (15-80)* 21 (13-64)

7 (5-16) 94 (66-140)* 89 (59-131)* 96 (78-136)* 38 (17-97)* 49 (19-123)* 69 (19-129)*° 37 (16-92)* 17 (8-95)*

7 (2-18) 11 (3-23) 14 (6-27) 14 (4-22)* 12 (0-26) 19 (7-31)*° 11 (0-27)• 16 (5-22)

(1)(2)(3): sampling points, see text. *p < 0.05 vs. t0, °p < 0.05 vs. point (1), • p = 0.01 vs. point (2)

Conclusions: 1) Platelet activation, degranulation and aggregate formation occur shortly after the start of HD. 2) Not only the dialyser, but also the roller pump contributes to platelet activation and degranulation. 3) As the number of platelet aggregates was maximal after the pump and declined after the dialyser, it is likely that these aggregates are fragile and disintegrate during passage through its capillaries.

°p = 0.01, *p = 0.04 vs. HD37

Conclusions: 1) Mean BP was most stable during HD35 , whereas, 2) platelet activation was lowest during HD37 . 3) Therefore, it is highly unlikely that a reduced platelet activation underlies the beneficial influence of cool dialysate temperature on IDH in clinical dialysis. 4) Hence, our data do not support the view that drugs that interfere with platelet activation lower the incidence of IDH. 1 Borgdorff P, Fekkes D, Tangelder GJ. Hypotension caused by extracorporeal circulation: serotonin from pump-activated platelets triggers nitric oxide release. Circulation. 2002 Nov 12;106(20):2588-93.

SP312 PLATELET ACTIVATION IN CLINICAL HEMODIALYSIS (HD): THE ROLE OF ROLLERPUMP 1

2

3

Mareille Gritters , Piet Borgdorff , Margreet Schoorl , Marianne Schoorl3 , Muriel P.C. Grooteman4 , Piet C.M. Bartels3 , Gert-Jan Tangelder2 , Menso J. Nube1 . 1 Nephrology, Medical Center Alkmaar, Alkmaar, Netherlands; 2 Physiology, VU University, Amsterdam, Netherlands; 3 Biochemistry, Medical Center Alkmaar, Alkmaar, Netherlands; 4 Nephrology, VU University Medical Center, Amsterdam, Netherlands Introduction: Immediately after the start of HD, various blood cell elements, including leucocytes and platelets, are activated in the extracorporeal circuit (ECC), which consists of needles, blood lines and the dialyser. As of yet, most interest has been focused on the impact of the dialyser in this respect. In rats, however, it has been shown that roller pump perfusion in an extracorporeal circuit (ECC) leads to platelet aggregation and subsequent serotonin release, most probably attributable to pump induced shear stress.1 Therefore, in the current study platelet behaviour was estimated during clinical HD at various time points both before and after the roller pump, and after the dialyser. Study design: Ten stable chronic HD patients were studied during a single HD session. Blood was taken from three sampling points in the ECC: (1) afferent line, prior to the roller pump, (2) in between roller pump and dialyser, (3) efferent line, after the dialyser. Samples were collected at t0 , t5 , t30 , t60 and t150 . Platelet activation, degranulation, aggregation and serotonin release were studied by measuring platelet CD62 expression, platelet factor

Dialysis – nutrition, malnutrition, oxidative stress, inflammation 1 SP313 EXPRESSION OF SURFACE ANTIGENS ON PERIPHERAL BLOOD T-CELLS IN CHILDREN ON MAINTENANCE HEMODIALYSIS WITH THE USE OF VITAMIN E-COATED DIALYSIS MEMBRANE

Maria Szczepanska, Krystyna Szprynger, Bogdan Mazur. Dialysis Division, Department of Pediatrics, Nephrology and Endocrinology of Childhood, Silesian Medical School, Zabrze, Poland Maintenance hemodialysis (HD) improves demonstrable metabolic parameters of patients with chronic renal failure (CRF), their volume control and nutritional status, but the frequency of morbidity and mortality still remains higher also among pediatric patients. In children with CRF impairment of immunity is observed. This particularly concerns cell-mediated immunity, which results in higher morbidity from viral infections, higher incidence of malignant complications, anergy in skin reactions of delayed hypersensitivity type and inadequate response towards T-dependent antigens. The pathogenesis of such alterations is not yet fully explained. The study aimed at analysis of T-cell subsets during 18 HD sessions in 6 adolescents on maintenance HD. 10 healthy children served as control group. In children treated with HD, T-cell subset configuration was compared before, at the time of 15 min from the beginning of the session (T15), and after hemodialysis session. Vit E-coated dialysis membrane was evaluated as compared to polysulfone and cuprophan membranes. The expression of surface antigens CD3, CD4, CD8, CD14, CD16, CD19, CD45, CD56, HLA-DR on peripheral blood (PB) mononuclear cells was evaluated using two-color flow cytometry (Becton Dickinson, Heidelberg, Germany). Results: During HD with vit E-coated membrane absolute number of lymphocytes with CD3, CD4, CD8, CD19, CD16/CD56 receptors was lowered at 15 min of the session, but the final values after HD were comparable to the baseline. CD3/HLA-DR T-cells were diminished at T15 and at the end of the session. CD3/HLA-DR T-cells were unchanged during HD with polysulfone membrane and diminished only at T15 with - cuprophan. For all applied membranes absolute number of CD3, CD4, CD8 cells was lower

Sunday, June 5, 2005

Dialysis – nutrition, malnutrition, oxidative stress, inflammation 1

and CD3/HLA-DR T-cells was higher than in the control group. The percentage of CD3, CD8 cells was lower at T15 and CD16/CD56 cells – after the HD session with vit E-coated membrane. At the T15 during HD with vit E-coated membrane the percentage of CD16/CD56 was significantly higher than during HD with cuprophan. The percentage of CD4 cells remained stable. During dialysis with polysulfone CD4 cells percentage was increased at T15 and after HD. During dialysis with cuprophan membrane CD4 cells percentage was increased at T15. The percentage of CD3/HLADR T-cells was unchanged for all the membranes and was lower than in the control group. The CD4/CD8 ratio was elevated during the application of each membrane and did not differ from healthy controls. Conclusions: T cell depletion in uremic patients results mostly from uremia-related toxicities rather than from treatment-related incompatibilities. We observed significant alteration within T cell compartment, which could be explained only by HD-related processes. However, we have not found the clear advantage of use vit E-coated membrane. Further studies on larger groups of children should be performed to evaluate the influence of vit E-coated dialyzer membrane on PB T-cells.

SP314 CHRONIC AND REPEATED SWIM STRESS INCREASES OXIDATIVE METABOLISM IN THE RAT KIDNEY

Adriana B. Pedreanez1 , Jose L. Arcaya2 , Edgardo Carrizo2 , Jesus A. Mosquera2 . 1 Immunology, Escuela de Bioanalisis, Maracaibo, Zulia, Venezuela; 2 Immunology and Neurochemistry, Investigaciones Clinicas “Dr. Americo Negrette”, Maracaibo, Zulia, Venezuela Clear evidence has shown that mechanisms of stress and depression can cause a disturbance of oxidative homeostasis. Previous reports have also shown that repeated stress induces kidney alterations such as increased renal renin production and diminished expression of peripheral-type benzodiazepine receptors. In the present study, we determined the effect of forced swimming test on the oxidative status of the kidney. Sprague-Dawley rats (n=10) were subjected to 30 min daily sessions of forced swimming for 15 consecutive days. Control rats were completely naïve (n= 9). Motor activity was automatically analyzed daily before swimming. In the forced swimming test group, both total horizontal activity and ambulatory movements exhibited a significant decrease, when the data from 1st and 15th day were compared (horizontal: 588.2 ± 99.74 vs 400 ± 83.21, p = 0.002; ambulatory: 359.5 ± 84.5 vs 233.5 ± 58.61, p=0.006). Biochemical, enzymatic and histochemical analysis from renal frozen sections and homogenized kidney sections revealed that chronic swim test significantly increased the number of superoxide anion (O2 - ) producing cells and the levels of nitric oxide (NO) and lipid peroxidation (MDA). The renal content of reduced glutathione (GSH) was decreased and the activity of catalase (CAT) was not significant changed. Oxidative status in rat kidney after forced swim test O2Control Swim P values

Glo

Int

Tub

1.05 ±0.99* 3.55 ±1.85 0.002

0.92 ±0.24 1.90 ±1.22 NS

0.95 ±0.59 5.33 ±4.59 0.007

NO

MDA

GSH

CAT

1.54 ±0.87 7.52 ±4.37