Abstract:
:Clinical and experimental studies have shown that serum aluminum (Al) is bound to transferrin and that cellular uptake of Al appears to be mediated by transferrin receptors. Based on these findings it is widely believed that intestinal Al absorption occurs via iron-specific, transferrin-dependent pathways and that iron (Fe) deficiency increases the intestinal absorption of Al. However, since no transferrin receptors are expressed on the absorptive surface of small intestinal epithelial cells this notion is doubtful. To further clarify the issue the present study investigated the effect of marked alterations of body Fe stores on the intestinal absorption of Al using three different rat models. (I) Serum Al concentrations and urinary excretion rates of Al were measured in iron-overloaded (Fe+) or iron-deficient (Fe-) rats with either normal (C) or impaired (5/6 nephrectomy) renal function (Nx) employing oral A1 loads in single dose studies. (II) Tissue A1 accumulation as well as serum and urine A1 were determined in respective experimental groups exposed to a prolonged (41 days) dietary Al load. (III) To assess the effect of Fe status on the intestinal absorption of Al directly at the organ level perfusions of in situ rat gut preparations were performed. In the single dose studies administration of Al resulted in similar urinary excretion rates of Al in intact kidney groups (C+Fe-, 229 +/- 85 nmol/5 days; C+Fe+, 240 +/- 59 nmol/5 days) despite marked differences in liver Fe (C+Fe-, 1.34 +/- 0.16 vs. C+Fe+, 55.69 +/- 13.20 mumol/g) and duodenal mucosal Fe (C+Fe-, 0.68 +/- 0.11 vs. C+Fe+, 3.17 +/- 0.82 mumol/g). In addition, mucosal Al concentration 24 hours after the load was not affected by the Fe status (C+Fe-, 37 +/- 16 nmol/g, C+Fe+, 56 +/- 19 nmol/g). Regardless of the Fe status post-load Al excretion was enhanced in Nx rats (Nx+Fe-, 533 +/- 234 nmol/five days, Nx+Fe+, 536 +/- 201 nmol/five days). Irrespective of Fe status a prolonged dietary Al load resulted in a similar increase in tissue Al concentration (nmol/g) in liver (baseline, 159 +/- 22; C+Fe-, 276 +/- 125; C+Fe+, 251 +/- 71; Nx+Fe-, 330 +/- 119; Nx+Fe+, 437 +/- 67) and in bone (baseline, 219 +/- 119; C+Fe-, 433 +/- 174, C+Fe+, 485 +/- 141; Nx+Fe-, 504 +/- 185; Nx+Fe+, 548 +/- 215). The increase in spleen Al was significantly larger in Fe-overloaded rats (baseline, 194 +/- 20; C+Fe+, 511 +/- 129 vs. C+Fe-, 308 +/- 62, P < 0.05; Nx+Fe+, 514 +/- 67 vs. Nx+Fe-, 389 +/- 119, P < 0.05). Brain Al tended to rise in Nx rats only (baseline, 96 +/- 33; Nx+Fe+, 174 +/- 100, Nx+Fe-, 156 +/- 78, P = NS). Analogous results were obtained in in situ intestinal perfusion studies: Fe deficiency and Fe overload both did not affect the time-dependent increase in serum Al in either systemic or portal vein blood. When paracellular intestinal permeability was assessed mannitol absorption was significantly higher in uremic animals as compared to controls. Pharmacological blockade (2 mM kinetin) of the paracellular permeability substantially reduced the time-dependent increase in serum Al in uremic rats but had little effect in control animals, suggesting that even the excess absorption of Al observed in uremia occurs via a paracellular rather than an iron-specific pathway. In conclusion, the findings of the present study provide several lines of evidence against the commonly accepted view that the intestinal absorption of Al occurs via iron-specific pathways. Most likely, this is related to the fact, that neither the absorption of Fe nor the absorption of Al are mediated via transferrin receptors. In addition, the enhanced intestinal absorption of Al observed in uremic rats does also not occur via iron-specific pathways, but seems to due to increased paracellular permeability of the intestine.
journal_name
Kidney Intjournal_title
Kidney internationalauthors
Ittel TH,Kinzel S,Ortmanns A,Sieberth HGdoi
10.1038/ki.1996.509subject
Has Abstractpub_date
1996-12-01 00:00:00pages
1879-88issue
6eissn
0085-2538issn
1523-1755pii
S0085-2538(15)59803-7journal_volume
50pub_type
杂志文章abstract::We compared the effects of calcitriol and doxercalciferol, in combination with either calcium carbonate or sevelamer, on bone, mineral, and fibroblast growth factor-23 (FGF-23) metabolism in patients with secondary hyperparathyroidism. A total of 60 pediatric patients treated with peritoneal dialysis were randomized t...
journal_title:Kidney international
pub_type: 杂志文章,随机对照试验
doi:10.1038/ki.2010.352
更新日期:2011-01-01 00:00:00
abstract::The molecular mechanism of Na+ and phosphate transport by the intestinal brush border membrane Na+/phosphate cotransporter was examined using anion and cation exchange columns interfaced to a light-activated microsecond timer. The nature of ion:cotransporter interaction was examined for sensitivity to itself versus no...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1038/ki.1996.141
更新日期:1996-04-01 00:00:00
abstract::The inactivation of physiological glucocorticoids by 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) confers mineralocorticoid specificity to certain aldosterone target tissues. Both NADP, and NAD-dependent isoforms of 11 beta-HSD have been described. An NAD-dependent isoform of 11 beta-HSD (11 beta-HSD2) was recen...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1038/ki.1996.39
更新日期:1996-01-01 00:00:00
abstract:BACKGROUND:The relationship between low hematocrit and contrast-induced nephropathy has not been investigated. METHODS:Of 6,773 consecutive patients treated with percutaneous coronary intervention, contrast-induced nephropathy (an increase of >/=25% or >/=0.5 mg/dL in preprocedure serum creatinine, at 48 hours postpro...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1111/j.1523-1755.2005.67131.x
更新日期:2005-02-01 00:00:00
abstract::Prior studies reported associations of APOL1 nephropathy risk variants with subclinical atherosclerosis. However, these findings were limited to older individuals with high comorbidities. To evaluate this in younger individuals, we calculated associations of APOL1 risk variants (high risk [2 risk variants] vs. low ris...
journal_title:Kidney international
pub_type: 杂志文章,多中心研究
doi:10.1016/j.kint.2017.08.019
更新日期:2018-03-01 00:00:00
abstract:BACKGROUND:Current renal substitution therapy for acute or chronic renal failure with hemodialysis or hemofiltration is life sustaining, but continues to have unacceptably high morbidity and mortality rates. This therapy is not complete renal replacement therapy because it does not provide active transport nor metaboli...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1046/j.1523-1755.1999.00486.x
更新日期:1999-06-01 00:00:00
abstract::The rate of myofibrillar protein degradation was measured by 3-methylhistidine (3MH) release in moderately uremic and sham-operated control rats. The rats were studied in the fed state or after 24 and 48 hours of fasting. When fed, both uremic and control rats gained weight at the same rate. During 48 hours of fasting...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1038/ki.1981.141
更新日期:1981-09-01 00:00:00
abstract:BACKGROUND:Low dietary phosphorus (P) prevents parathyroid gland (PTG) hyperplasia and the development of secondary hyperparathyroidism (SH) in uremic rats. The present study explores the effects of P restriction on parathyroid hormone (PTH) synthesis and secretion and PT cell growth in rats with established SH and PTG...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1046/j.1523-1755.2002.00265.x
更新日期:2002-04-01 00:00:00
abstract::Recent studies including the current article by Sawinski et al. demonstrate that hepatitis C virus (HCV) infection is associated with worse outcomes in kidney transplant recipients with and without HIV infection. We comment on the significance of these findings in the context of newer options for the treatment of HCV ...
journal_title:Kidney international
pub_type: 评论,杂志文章
doi:10.1038/ki.2015.180
更新日期:2015-08-01 00:00:00
abstract::Tubular function studies have shown that nephrectomy leads to a sharp increase in potassium secretion by initial collecting tubules. The aim of this study was to examine the relationship between potassium transport and the cellular morphology of the distal nephron. Clearance and ultrastructural studies were conducted ...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1038/ki.1985.58
更新日期:1985-04-01 00:00:00
abstract::Whole-genome microarrays identify large numbers of gene expression changes that appear specifically related to disease states such as antineutrophil cytoplasmic autoantibody (ANCA) and systemic lupus erythematosus. Although understanding this enormous volume of esoteric data is difficult, a few basic concepts regardin...
journal_title:Kidney international
pub_type: 评论,杂志文章
doi:10.1038/sj.ki.5002492
更新日期:2007-10-01 00:00:00
abstract::Fixed anionic sites within the glomerular capillary wall influence the permeation of serum proteins, the localization of various antigens, and the deposition of antibody in the subepithelial space. In anti-GBM nephritis antibody deposition occurs very rapidly to antigenic sites located relatively proximal in the glome...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1038/ki.1984.188
更新日期:1984-10-01 00:00:00
abstract:BACKGROUND:Cold ischemia and reperfusion during kidney transplantation are associated with release of free oxygen radicals and damage of renal tubular cells. Bioflavonoids may diminish cold storage-induced injury due to antioxidant and iron chelating activities. This study was designed to delineate the renoprotective m...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1046/j.1523-1755.2003.00774.x
更新日期:2003-02-01 00:00:00
abstract::Aminopeptidase A is one of the most potent enzymes within the renin-angiotensin system in terms of angiotensin II degradation. Here, we examined whether there is a kidney phenotype and any compensatory changes in other renin angiotensin system enzymes involved in the metabolism of angiotensin II associated with aminop...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1016/j.kint.2020.11.012
更新日期:2020-12-11 00:00:00
abstract::Sodium depletion has a protective effect on target-organ damage in hypertension independent of blood pressure. Here we tested whether chronic dietary sodium restriction may prevent the development of renal alterations associated with insulin resistance by reducing the inflammatory and oxidant state. Rats were fed norm...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1038/ki.2012.478
更新日期:2013-04-01 00:00:00
abstract:BACKGROUND:Crystals of calcium oxalate monohydrate (COM) and excess oxalate ions (OX) stimulate an array of responses inducing localized injury and inflammation in the kidneys. These inflammatory responses are key regulators of development of nephrolithiasis. We propose that monocyte chemoattractant protein-1 (MCP-1), ...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1046/j.1523-1755.2002.00106.x
更新日期:2002-01-01 00:00:00
abstract::Daily calcitriol therapy has been reported to improve linear growth in children with renal bone disease, and 1,25-dihydroxyvitamin D is a key regultor of chondrocyte proliferation and differentiation. Whereas large intermittent doses of calcitriol can lower serum parathyroid hormone (PTH) levels and reverse the skelet...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1046/j.1523-1755.1998.00724.x
更新日期:1998-01-01 00:00:00
abstract:BACKGROUND:The benefit of the potent chemotherapeutic agent cisplatin in treating neoplasms is limited by nephrotoxicity. We tested the hypothesis that CD54 [intercellular adhesion molecule-1 (ICAM-1)] is an important mediator in cisplatin-mediated renal failure. METHODS:The effect of a monoclonal anti-CD54 antibody w...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1046/j.1523-1755.1999.00629.x
更新日期:1999-09-01 00:00:00
abstract::An effective therapeutic means to remove relatively large polypeptide uremic toxins seems to be a hemofiltration (HF) or hemodiafiltration (HDF) employing a larger-pore membrane, that is, a protein-permeable membrane. With either method, however, a significant amount of albumin will be lost into the ultrafiltrate or d...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1038/ki.1996.333
更新日期:1996-08-01 00:00:00
abstract:BACKGROUND:Unilateral ureteral obstruction (UUO) leads to interstitial fibrosis of the obstructed kidney, and TGF-beta is considered to play an important role in this fibrotic process. Smad7 has been recently identified as an antagonist of TGF-beta signaling. To investigate whether this novel molecule can be exploited ...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1046/j.1523-1755.2002.0610s1094.x
更新日期:2002-01-01 00:00:00
abstract::Progression of diabetic nephropathy appears directly related to renal tubulointerstitial injury, but the involved genes are incompletely delineated. To identify such genes, DNA microarray analysis was performed with RNA from renal proximal tubules (RPTs) of streptozotocin-induced diabetic Wistar rats, spontaneously di...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1038/sj.ki.5000206
更新日期:2006-03-01 00:00:00
abstract::The effects of acidosis on renal function and morphology were examined in the isolated perfused rat kidney (IPK). Kidneys were perfused with oxygenated Krebs-Henseleit-albumin medium for 60 minutes at pH 7.4 or pH 7.0. At the lower pH, GFR was reduced by 25%, TRNa by 32% and oxygen consumption by 41% as compared to pe...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1038/ki.1988.251
更新日期:1988-12-01 00:00:00
abstract:BACKGROUND:Nephrologists report that patients' choice should play an important role in the selection of renal replacement therapy (RRT) for end-stage renal disease (ESRD). In the United States, kidney transplant rates remain low and <10% of patients utilize home dialysis therapies. This study examined the effect of pre...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1111/j.1523-1755.2005.00453.x
更新日期:2005-07-01 00:00:00
abstract:BACKGROUND:We have recently demonstrated an increase in apoptosis in Han:SPRD rat kidneys with autosomal-dominant polycystic kidney disease (ADPKD). Caspase-3 and caspase-7 are major mediators of apoptosis. There are two pathways of caspase-3 and caspase-7-mediated apoptosis: (1) the "extrinsic" pathway involving the d...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1111/j.1523-1755.2005.00155.x
更新日期:2005-03-01 00:00:00
abstract::Potassium transport in the thick ascending limb is conducted by heterogeneous cells to opposite directions. Effects of glucocorticoids and mineralocorticoids on potassium transport of the rat medullary thick ascending limb (MTAL) were examined by in vitro microperfusion technique by measuring net potassium flux (JK), ...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1038/ki.1995.122
更新日期:1995-03-01 00:00:00
abstract:BACKGROUND:Hypercholesterolemia may affect both endothelial function and arterial distensibility (DC). Renal transplant recipients (NTX) exhibit advanced structural and functional alterations of arterial vessel walls. The aim of this double-blind, randomized trial was to evaluate the effects of fluvastatin (FLU) on bra...
journal_title:Kidney international
pub_type: 临床试验,杂志文章,随机对照试验
doi:10.1046/j.1523-1755.2001.0590041473.x
更新日期:2001-04-01 00:00:00
abstract::Human transitional B cells express relatively high IL-10 and low TNF-α levels, which correlate with B regulatory activity in vitro. Herein, we aim to further define B regulatory phenotype and determine whether B regulatory activity can serve as a prognostic marker for renal allograft dysfunction (graft loss or 2-fold ...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1016/j.kint.2016.08.028
更新日期:2017-01-01 00:00:00
abstract::Vitamin D hydroxylated at carbon 25 (25(OH)D) is generally recognized as a precursor of active vitamin D. Despite its low affinity for the vitamin D receptor (VDR), both deficient and excessive 25(OH)D levels are associated with poor clinical outcomes. Here we studied direct effects of 25(OH)D3 on the kidney using 25(...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1038/ki.2015.210
更新日期:2015-11-01 00:00:00
abstract:BACKGROUND:Wegener's granulomatosis (WG) is characterized by systemic vasculitis with crescentic glomerulonephritis (CGN) and circulating autoantibodies directed against neutrophil cytoplasmic antigens (ANCA). Proteinase 3 (PR-3), a neutral serine proteinase in neutrophils implicated in the growth control of myeloid ce...
journal_title:Kidney international
pub_type: 杂志文章
doi:10.1046/j.1523-1755.2000.00100.x
更新日期:2000-06-01 00:00:00
abstract::As new components of the renin-angiotensin system (RAS) are elucidated, our understanding of the complexities of their interactions also advances. Previous studies have determined that podocytes possess a local RAS that can generate angiotensin II. Podocytes have also been shown to express angiotensin-converting enzym...
journal_title:Kidney international
pub_type: 评论,杂志文章
doi:10.1038/ki.2012.127
更新日期:2012-08-01 00:00:00