A compensatory mechanism improving red cell membrane fluidity in hemodialysed patients

Peuchant, Evelyne; Motta, Claude; Salles, Christine; Clerc, M

doi:10.1016/0009-8981(90)90280-6

Cited by 8 publications

(6 citation statements)

References 24 publications

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“…Decreases in total and LDL-cholesterol have been shown to be associated with a relative increase in SFA and decrease in PUFA in patients with renal failure on haemodialysis, and after plasmapheresis in subjects with familial hypercholesterolaemia (Brook et al 1983, Peuchant et al 1990). Although this mechanism remains a possibility, no correlation between the changes in platelet membrane fatty acids and those in serum lipoproteins was observed in this study.…”

Section: Discussionmentioning

confidence: 98%

Effects of hormone replacement therapy on platelet membrane fatty acid composition

Ranganath¹,

Christofides²,

Wright³

et al. 1996

Journal of Endocrinology

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Oestrogen replacement therapy has been shown to protect postmenopausal women from ischaemic heart disease, strokes and hypertension. The mechanism of protection conferred by oestrogen, although partly attributable to changes in serum lipoproteins, is not fully understood. The present study was undertaken to assess the effect of hormone replacement therapy on the composition of platelet membrane fatty acids in postmenopausal women. These were analysed by gas-liquid chromatography before and six weeks after continuous conjugated equine oestrogen therapy (0.625 mg daily) combined with cyclical therapy with 75 micrograms L-norgestrel from day 17 to 28 of a 28-day cycle. Each subject acted as her own control. The principal findings of the study were that, following treatment, there was a 16.2% reduction in platelet membrane polyunsaturated fatty acids (P < 0.001), an increase of 9.1 and 7.1% in saturated fatty acids and monounsaturated fatty acids respectively (P < 0.001) and a 17.8% reduction in arachidonic acid (P < 0.003). There was no correlation between changes in membrane fatty acids and serum lipoproteins. This suggests that the changes in membrane composition noted in this study may be a primary effect of hormone replacement therapy, especially oestrogen.

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Section: Discussionmentioning

confidence: 98%

Effects of hormone replacement therapy on platelet membrane fatty acid composition

Ranganath¹,

Christofides²,

Wright³

et al. 1996

Journal of Endocrinology

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“…Decreased enzyme activity has been suggested to be the consequence of the presence of various endogenous digoxin-like factors ( E D L F ) (6)(7)(8). Altered physicochemical properties of human erythrocyte membranes in uraemic patients (9,10) could also result in changes in enzyme activity. In spite of these data the mechanism of decreased N;i+-K+ ATPase activity in uraemia remains to be clarified.…”

mentioning

confidence: 99%

Altered Na⁺‐K⁺ ATPase activity in uraemic adolescents

et al. 1996

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The Na(+)-K+ ATPase enzyme plays an essential role in the regulation of cell composition and volume. Enzyme activity itself is regulated by substrate availability and several hormones. In adult uraemic patients red blood cell Na(+)-K+ ATPase activity is decreased. However, it is unknown if children with uraemia exhibit the same phenomenon. Therefore, in the present study we examined whether endogenous digoxin-like factors (EDLF) and physicochemical membrane properties play a role in the regulation of erythrocyte Na(+)-K+ ATPase activity in uraemic children and adolescents. Healthy age-matched children were used as controls. Enzyme activity was measured in detergent-pretreated red blood cells and erythrocyte ghosts. Na(+)-K+ ATPase activity (2204 +/- 538 nmol Pi ml erythrocyte-1 h-1 in detergent pretreated erythrocytes; 204 +/- 56 nmol Pi mg protein-1 h-1 in ghosts) in adolescents with uraemia was lower compared to controls (3245 +/- 362 nmol Pi ml erythrocyte-1 h-1; 266 +/- 37 nmol Pi mg protein-1 h-1, p < 0.001, p < 0.05, respectively). Plasma levels of EDLF were elevated in uraemic patients (0.30 +/- 0.05 versus 0.21 +/- 0.04 ng ml-1, p < 0.01). Furthermore, the membrane lipid component was decreased in patients with uraemia, while the cholesterol/phospholipid ratio and membrane fluidity were similar in both groups. No correlation was found between the decrease in Na(+)-K+ ATPase and the increase in EDLF concentration and altered membrane lipid components. Our results demonstrate, that similar to the findings of adults, the activity of Na(+)-K+ ATPase is diminished in uraemic adolescent patients, and that uraemia-associated elevation in EDLF and altered membrane components do not play a role in the down-regulation of Na(+)-K+ ATPase. Therefore other factors (presence of other inhibitors and/or reduced number of enzyme molecules) should contribute to the lower activity of the Na(+)-K+ pump.

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“…Since EDLF may be involved in the regulation of Na + /K + ATPase activity, one may speculate that endogenous Na + pump inhibitors could be the reason for the decreased enzyme activity in uremic children and adolescents. However, the lack of direct correlation between EDLF and Na + pump inhibition suggests that the regulation of the Na + /K + ATP-ase activity is more complex, including other possible inhibitors and/or the alteration of lipid microenvironment of the enzyme [7,11]. Similarly, the lack of correlation between blood pressure and EDLF suggests that EDLF does not play a central role in the hypertension of CRF.…”

Section: Discussionmentioning

confidence: 79%

“…Its impairment results in significant changes in intra-and extracellular volume and cationic homeostasis. In cases of lower Na + /K + ATP-ase activity the intracellular Ca 2+ elevates, leading to higher blood pressure and enhancement of myocardial contractility [8,9,10,11].…”

Section: Introductionmentioning

confidence: 99%

Monitoring cardiovascular changes during hemodialysis in children

Miltényi

Tory

Stubnya

et al. 2001

Pediatric Nephrology

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Hemodialysis (HD) causes rapid volume shifts and circulatory changes. In chronic renal failure (CRF) Na+/K+ATP-ase is depressed, whereas endogenous digoxin-like factor (EDLF) is elevated. Our aim was to characterize HD-induced cardiovascular adaptation and its possible links to Na+/K+ATP-ase and EDLF. Eleven children with CRF on HD (aged 14.7 +/- 3.7 years) and 11 healthy children were investigated for basic circulatory parameters. Thoracic impedance (Zo) and circulatory parameters were monitored by impedance cardiography (ICG) during HD. Erythrocyte Na+/K+ATP-ase and EDLF were measured before and after HD. Up to the loss of 6% of total body weight, Zo rose linearly with fluid removal, above this no further increase occurred. Heart rate and mean arterial pressure (MAP) were inversely related (r = -0.97); MAP rose in the first and decreased in the second part of HD. Systemic vascular resistance paralleled MAP, whereas stroke volume rapidly decreased, but stabilized in the second part of HD. The ratio of preejection period/ventricular ejection time (PEP/VET) correlated positively with HD duration (r = 0.92), suggesting diminished cardiac filling. Cardiac index (CI) remained stable. EDLF was high in uremia accompanied by depressed Na+/K+ATP-ase (P < 0.05 and P < 0.01, respectively). Following HD Na+/K+ATP-ase normalized. Correlation between Na+/K+ATP-ase activity and MAP was linear (r = 0.85). In conclusion, ICG during HD provides detailed information concerning circulatory adaptation resulting in stable CI, suggesting that the dialysis-induced hypovolemia is compensated by the centralization of the blood volume. Changes of Na+/K+ATP-ase indicate that dialyzable blood pressure-regulating substance(s) inhibit(s) the pump. However, lack of further correlation between Na+/K+ATP-ase, EDLF, and cardiovascular parameters indicates the complexity of the regulatory processes.

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A compensatory mechanism improving red cell membrane fluidity in hemodialysed patients

Cited by 8 publications

References 24 publications

Effects of hormone replacement therapy on platelet membrane fatty acid composition

Effects of hormone replacement therapy on platelet membrane fatty acid composition

Altered Na⁺‐K⁺ ATPase activity in uraemic adolescents

Monitoring cardiovascular changes during hemodialysis in children

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A compensatory mechanism improving red cell membrane fluidity in hemodialysed patients

Cited by 8 publications

References 24 publications

Effects of hormone replacement therapy on platelet membrane fatty acid composition

Effects of hormone replacement therapy on platelet membrane fatty acid composition

Altered Na+‐K+ ATPase activity in uraemic adolescents

Monitoring cardiovascular changes during hemodialysis in children

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Altered Na⁺‐K⁺ ATPase activity in uraemic adolescents