A Djemli-Shipkolye

Publications (7)12.15 Total impact

• Article: Differential effect of omega3 PUFA supplementations on Na,K-ATPase and Mg-ATPase activities: possible role of the membrane omega6/omega3 ratio.

  A Djemli-Shipkolye, D Raccah, G Pieroni, P Vague, T C Coste, A Gerbi
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  ABSTRACT: Several functional properties of Na,K-ATPase are strongly dependent on membrane fatty acid composition, but the underlying mechanism is still not well defined. We have studied the effects of two types of supplementations enriched in the w3 polyunsaturated fatty acids on the Na,K-ATPase and Mg-ATPase activities in sciatic nerve (SN) and red blood cells (RBC). Eight groups of rats, controls and diabetics, received a standard diet, supplemented or not with 30 or 60 mg/kg/day of docosahexaenoic acid (DHA) or with soybean for eight weeks. Diabetes induced significant decrease of Na,K-ATPase activity in SN (-23%) and RBC (-25%), without affecting Mg-ATPase activity. In RBC, soybean and DHA supplementations caused significant increases in Na,K-ATPase activity (in various range, +13% to +145%) in all groups, and in Mg-ATPase activity in control soybean (+65%), control and diabetic DHA high dose (+39%, +53%) and diabetic DHA low dose (+131%) groups. In SN, the soybean caused a significant decrease in Na,K-ATPase activity (-26%) and still more in the diabetic group (-53%). The DHA diet induced a slight decrease in activity in control groups, whilst during diabetes, at high dose, we noted an aggravation of this decrease (-36%). Mg-ATPase activity was not modified by supplementations except for the low dose of DHA where the activity was slightly decreased in the control group (-16%). The supplementations induced multiple tissue-specific modifications in the membrane fatty acid composition of RBC and of SN homogenates. Several specific correlations have been found between variations in fatty acids amounts and Na,K-ATPase activity in these tissues but only in RBC for Mg-ATPase activity. Indeed, we observed that the variations in Na,K-ATPase activity are positively and significantly correlated with changes in the omega6/omega3 ratio in SN as well as in RBC. These data clearly show, for the first time, that the diet could modulate the Na,K-ATPase activity via the omega6/omega3 ratio in the membranes. A similar correlation was observed with Mg-ATPase activity in RBC, suggesting also a dietary regulation of the enzyme; but for the SN, this activity might be regulated by a different omega6/omega3 ratio or by another pathway.
  Journal of Membrane Biology 02/2003; 191(1):37-47. · 1.81 Impact Factor
• Article: Differential Effect of w3 PUFA Supplementations on Na,K-ATPase and Mg-ATPase Activities: Possible Role of the Membrane w6/w3 Ratio

  A. Djemli-Shipkolye, D. Raccah, G. Pieroni, P. Vague, T.C. Coste, A. Gerbi
  [show abstract] [hide abstract]
  ABSTRACT: Several functional properties of Na,K-ATPase are strongly dependent on membrane fatty acid composition, but the underlying mechanism is still not well defined. We have studied the effects of two types of supplementations enriched in the w3 polyunsaturated fatty acids on the Na,K-ATPase and Mg-ATPase activities in sciatic nerve (SN) and red blood cells (RBC). Eight groups of rats, controls and diabetics, received a standard diet, supplemented or not with 30 or 60 mg/kg/day of docosahexaenoic acid (DHA) or with soybean for eight weeks. Diabetes induced significant decrease of Na,K-ATPase activity in SN (?23%) and RBC (?25%), without affecting Mg-ATPase activity. In RBC, soybean and DHA supplementations caused significant increases in Na,K-ATPase activity (in various range, +13% to +145%) in all groups, and in Mg-ATPase activity in control soybean (+65%), control and diabetic DHA high dose (+39%, +53%) and diabetic DHA low dose (+131%) groups. In SN, the soybean caused a significant decrease in Na,K-ATPase activity (?26%) and still more in the diabetic group (?53%). The DHA diet induced a slight decrease in activity in control groups, whilst during diabetes, at high dose, we noted an aggravation of this decrease (?36%). Mg-ATPase activity was not modified by supplementations except for the low dose of DHA where the activity was slightly decreased in the control group (?16%). The supplementations induced multiple tissue-specific modifications in the membrane fatty acid composition of RBC and of SN homogenates. Several specific correlations have been found between variations in fatty acids amounts and Na,K-ATPase activity in these tissues but only in RBC for Mg-ATPase activity. Indeed, we observed that the variations in Na,K-ATPase activity are positively and significantly correlated with changes in the w6/w3 ratio in SN as well as in RBC. These data clearly show, for the first time, that the diet could modulate the Na,K-ATPase activity via the w6/w3 ratio in the membranes. A similar correlation was observed with Mg-ATPase activity in RBC, suggesting also a dietary regulation of the enzyme; but for the SN, this activity might be regulated by a different w6/w3 ratio or by another pathway.
  Journal of Membrane Biology 12/2002; 191(1):37-47. · 1.81 Impact Factor
• Article: Gamma-linolenic acid restores renal medullary thick ascending limb Na(+),K(+)-ATPase activity in diabetic rats.

  M Tsimaratos, T C Coste, A Djemli-Shipkolye, P Vague, G Pieroni, D Raccah
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  ABSTRACT: In diabetes, the activity of Delta-6 desaturase, which converts linoleic acid (LA) into gamma-linolenic acid (GLA), the first step of arachidonic acid (AA) synthesis, is decreased, leading to alterations in membrane phospholipid composition. On the other hand, 12 wk after the onset of diabetes, Na(+),K(+)-ATPase activity is reduced in many organs, including the kidney. The medullary thick ascending limb (MTAL) reduced Na(+),K(+)-ATPase activity, whereas the sodium load secondary to glomerular hyperfiltration was increased. The aim of our study was to examine whether the changes in membrane fatty acid composition resulting from the inhibition of Delta-6 desaturase may be involved in the decreased Na(+),K(+)-ATPase activity observed in the outer MTAL after 12 wk of diabetes. GLA is a fatty acid that by-passes the Delta-6 desaturase step. We measured the membrane fatty acid composition and the Na(+),K(+)-ATPase activity in the renal outer medulla of control and streptozotocin (STZ)-induced diabetic rats 12 wk after the induction of diabetes. Measurements were performed after supplementation of control rats with sunflower oil (SO) or GLA for 12 wk, and supplementation of 12 wk diabetic rats with SO for 12 wk or with GLA for 6 or 12 wk. Supplementation with GLA not only prevented the decrease in Na(+),K(+)-ATPase activity observed after 12 wk of diabetes but also time dependently stimulated Na(+),K(+)-ATPase activity in the outer medulla. The changes in Na(+),K(+)-ATPase activity were related to parallel changes in the amount of Na(+),K(+)-ATPase alpha(1) subunit protein. In addition, in diabetic rats only, Na(+),K(+)-ATPase activity was positively correlated with the amount of AA present in cell membranes (r = 0.92, P < 0.05). Our results indicate that nutritional GLA supplementation increases Na(+),K(+)-ATPase activity and expression in diabetic rats. In addition, the positive correlation between AA content and Na(+),K(+)-ATPase activity suggests that in diabetic rats, alterations in membrane fatty acid composition contribute to the decreased Na(+),K(+)-ATPase activity in outer medulla.
  Journal of Nutrition 12/2001; 131(12):3160-5. · 3.92 Impact Factor
• Article: Evidence of time-dependent changes in renal medullary Na,K-ATPase activity and expression in diabetic rats.

  M Tsimarato, T C Coste, A Djemli-Shipkolye, L Daniel, F Shipkolye, P Vague, D Raccah
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  ABSTRACT: The medullary thick ascending limb (MTAL) of the kidney displays structural changes during long term diabetes. After twelve weeks of diabetes, there is controversy over the changes in Na,K-ATPase activity. To observe the long-term changes, we studied MTAL Na,K-ATPase activity and protein expression in diabetic animals 6 (6W) and 12 weeks (12W) after induction of diabetes with streptozotocin. Three groups were studied, one control group, one group 6W after, and one group 12W after induction of diabetes. Membrane fractions from the inner strip of the outer medulla representing MTAL were isolated. Na,K-ATPase activity and western blottings of alpha1- and beta1-subunits were carried out. 6W diabetes resulted in an increase, and 12W in a decrease in the MTAL Na,K-ATPase activity versus the control group (respectively 63.3 +/- 21.2; 7.5 +/- 2.4 and 31.6 +/- 11.4; micromol Pi/mg prot/hr +/- SEM). The Na,K-ATPase subunit expression was increased at 6W, and decreased after 12W, resulting in amounts below control values for both alpha1- and beta1-subunits. Our results confirm a diabetes-induced biphasic time-dependent alteration MTAL Na,K-ATPase activity, supported by similar changes in alpha1 and beta1 Na,K-ATPase subunits-expression.
  Cellular and molecular biology 04/2001; 47(2):239-45. · 0.98 Impact Factor
• Article: Na,K-atpase alterations in diabetic rats: relationship with lipid metabolism and nerve physiological parameters.

  A Djemli-Shipkolye, T Coste, D Raccah, P Vague, G Pieroni, A Gerbi
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  ABSTRACT: Type 1 diabetes induces several metabolic and biochemical disturbances which result in the alteration ofNa,K-ATPase, an enzyme implicated in the physiopathology of neuropathy Several fatty acid supplementations lessen this alteration. The aims of this study were to determine the possible relationships between Na,K-ATPase activity in nerves and red blood cells (RBCs) and, on one hand, the fatty acid alterations induced by diabetes in these tissues and plasma and on the other, on nerve physiological parameters. Two groups of rats, control and diabetic (n = 15), were sacrified 8 weeks after induction of diabetes with streptozotocin. Nerve conduction velocity (NCV), nerve blood flow (NBF), Na,K-ATPase activity and membrane fatty acid composition of sciatic nerves, red blood cells (RBCs) and plasma were measured. NCV, NBF and Na,K-ATPase activity in RBCs and in sciatic nerves were significantly decreased in diabetic rats. We revealed a positive correlation between Na,K-ATPase activity in sciatic nerves and both NBF and NCV and between Na,K-ATPase activity in RBCs and NBF and the same activity in sciatic nerve. Diabetes induced major changes in plasma fatty acids and RBC membranes and less important changes in sciatic nerve membranes. Na,K-ATPase activity correlated negatively with C20: 4 (n-6) and C22: 4 (n-6) levels in nerves and with C18: 2 (n-6) levels in RBCs. During diabetes, changes in the membrane fatty acid composition suggest the existence of a tissue-specific regulation, and the decrease in Na,K-ATPase activity correlates with the alteration in the level of specific fatty acids in RBCs and sciatic nerves. Modifications in the lipidic environment of Na,K-ATPase would be involved in the alteration of its activity. Na,K-ATPase activity seems to be implicated in the decrease of both NCV and NBF during diabetes.
  Cellular and molecular biology 04/2001; 47(2):297-304. · 0.98 Impact Factor
• Article: The effects ex vivo and in vitro of insulin and C-peptide on Na/K adenosine triphosphatase activity in red blood cell membranes of type 1 diabetic patients.

  A Djemli-Shipkolye, P Gallice, T Coste, M F Jannot, M Tsimaratos, D Raccah, P Vague
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  ABSTRACT: The decrease in Na/K adenosine triphosphatase (ATPase) activity observed in several tissues of type 1 diabetic patients is thought to play a role in the development of long-term complications. Infusion of insulin may restore this enzyme activity in red blood cells (RBCs), and recent arguments have been developed for a similar role of C-peptide. The aims of this study were to determine whether insulin acts directly on the RBC enzyme and to evaluate the effect of C-peptide on Na/K ATPase activity. Thirty-nine C-peptide-negative type 1 diabetic patients were studied (blood glucose, 11.2 +/- 1.49 mmol/L; hemoglobin A1c [HbA1c], 8.9% +/- 0.1%, mean +/- SEM). Blood samples were obtained in the morning, before breakfast and insulin injection. Intact and living RBCs were resuspended in their own plasma and incubated with or without insulin (50 microU/mL) or C-peptide (6 nmol/L). Ex vivo by microcalorimetry, the heat produced after 1 hour by the enzyme-induced hydrolysis of adenosine triphosphate (ATP), was measured in a thermostated microcalorimeter at 37 degrees C. The results showed that Na/K ATPase activity was significantly increased by insulin (12.4 +/- 0.5 v 15.4 +/- 0.9 mW/L RBCs, P < .05, n = 23) but not by C-peptide (11.9 +/- 0.7 v 12.9 +/- 0.9 mW/L RBCs, NS, P = .26, n = 12). In another experiment, RBC suspensions were incubated at 37 degrees C in a water bath with or without insulin (50 microU/mL) or C-peptide (6 nmol/L) for 10 minutes. RBC membranes were isolated and Na/K ATPase activity was assessed by measuring inorganic phosphate release at saturating concentrations of all substrates. The results showed that insulin and C-peptide significantly increased RBC Na/K ATPase activity (342 +/- 25, P < .005 and 363 +/- 30, P < .005, respectively v255 +/- 22 nmol Pi x mg protein(-1) x h(-1), n = 14). We conclude that insulin and C-peptide act directly on RBC Na/K ATPase, thus restoring this activity in type 1 diabetic patients. The stimulatory effect of C-peptide observed in vitro on RBC Na/K ATPase activity confirms that C-peptide plays a physiological role.
  Metabolism 08/2000; 49(7):868-72. · 2.66 Impact Factor
• Article: The effects ex vivo and in vitro of insulin and C-peptide on Na/K adenosine triphosphatase activity in red blood cell membranes of type 1 diabetic patients

  A. Djemli-Shipkolye, P. Gallice, T. Coste, M.F. Jannot, M. Tsimaratos, D. Raccah, P. Vague
  [show abstract] [hide abstract]
  ABSTRACT: The decrease in Na/K adenosine triphosphatase (ATPase) activity observed in several tissues of type 1 diabetic patients is thought to play a role in the development of long-term complications. Infusion of insulin may restore this enzyme activity in red blood cells (RBCs), and recent arguments have been developed for a similar role of C-peptide. The aims of this study were to determine whether insulin acts directly on the RBC enzyme and to evaluate the effect of C-peptide on Na/K ATPase activity. Thirty-nine C-peptide—negative type 1 diabetic patients were studied (blood glucose, 11.2 ± 1.49 mmol/L; hemoglobin A1c [HbA1c], 8.9 ± 0.1%, mean ± SEM). Blood samples were obtained in the morning, before breakfast and insulin injection. Intact and living RBCs were resuspended in their own plasma and incubated with or without insulin (50 μU/mL) or C-peptide (6 nmol/L). Ex vivo by microcalorimetry, the heat produced after 1 hour by the enzyme-induced hydrolysis of adenosine triphosphate (ATP), was measured in a thermostated microcalorimeter at 37°C. The results showed that Na/K ATPase activity was significantly increased by insulin (12.4 ± 0.5 v 15.4 ± 0.9 mW/L RBCs, P < .05, n = 23) but not by C-peptide (11.9 ± 0.7 v 12.9 ± 0.9 mW/L RBCs, NS, P = .26, n = 12). In another experiment, RBC suspensions were incubated at 37°C in a water bath with or without insulin (50 μU/mL) or C-peptide (6 nmol/L) for 10 minutes. RBC membranes were isolated and Na/K ATPase activity was assessed by measuring inorganic phosphate release at saturating concentrations of all substrates. The results showed that insulin and C-peptide significantly increased RBC Na/K ATPase activity (342 ± 25, P < .005 and 363 ± 30, P < .005, respectively v 255 ± 22 nmol Pi·mg protein−1 · −1, n = 14). We conclude that insulin and C-peptide act directly on RBC Na/K ATPase, thus restoring this activity in type 1 diabetic patients. The stimulatory effect of C-peptide observed in vitro on RBC Na/K ATPase activity confirms that C-peptide plays a physiological role.
  Metabolism.