title: Short communication: Ischemia increases cortical Na⁺,K⁺-ATPase activity (K-Pase) in a model of kidney auto-transplantation in the large white pig.
abstract: Acute renal failure (ARF) induced by Ischemia-Reperfusion (I-R) is associated with a significant impairment of tubular sodium reabsorption. Na⁺,K⁺-ATPase has a crucial role in tubular sodium reabsorption and maintenance of water and ion homeostasis. In this study, we examined whether renal I-R affects Na⁺,K⁺-ATPase activity in a renal auto graft model (Large White Pig) with controlateral nephrectomy. Kidney samples were obtained from medulla (n = 4) and cortex (n = 3) after one hour of warm ischemia in autotransplanted models. These experimental groups were compared with a controlateral nephrectomy group (Control). Na⁺,K⁺-ATPase activity in purified membrane fractions was measured as ouabain-sensitive K⁺ -stimulated paranitrophenyl phosphatase (pNPPase) activity. The Na⁺,K⁺-ATPase activities of control, ischemia and ischemia -reperfusion were significantly higher in the medulla than in the cortex, irrespective of the experimental group (P<0.05). In cortices, Na⁺,K⁺-ATPase activity increased significantly (P<0.05) by 35% after ischemia compared to control group. In medullae, there was only a trend toward an activation of Na⁺,K⁺-ATPase activity after Ischemia (increased by 25%) and after Ischemia-Reperfusion (increased by 30%) compared to control group, and these differences did not reach statistical significance. These data suggest that renal ischemia induces a significant alteration of Na⁺,K⁺-ATPase by increasing its ouabain-sensitive K⁺-stimulated paranitrophenyl phosphatase (pNPPase) activity in isolated membrane from cortical renal tissues after one hour of ischemia. This change of activity seems to be a new regulation mechanism of an important membrane ion transporter during renal I-R in the large pig model of renal transplantation.
authors.affiliation: Universit&eacute; de Poitiers, Isch&eacute;mie&mdash;reperfusion en transplantation r&eacute;nale, CHU la Mil&eacute;terie Inserm U927 Poitiers France.
authors.forename: M
authors.initials: M
authors.lastname: Fares
authors.affiliation: Universit&eacute; de Poitiers, Isch&eacute;mie&mdash;reperfusion en transplantation r&eacute;nale, CHU la Mil&eacute;terie Inserm U927 Poitiers France.
authors.forename: C
authors.initials: C
authors.lastname: François
authors.affiliation: Universit&eacute; du Sud Toulon&mdash;Var EB2M&mdash;Prot&eacute;e La Garde France jmmaixent&commat;gmail.com.
authors.forename: J M
authors.initials: JM
authors.lastname: Maixent
mesh_terms: D058186:Acute Kidney Injury / Q000378:metabolism*; D000818:Animals; D016030:Kidney Transplantation; D009392:Nephrectomy; D015427:Reperfusion Injury / Q000150:complications*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D034421:Sus scrofa; D014182:Transplantation, Autologous
chemical_list: D000254:Sodium-Potassium-Exchanging ATPase