Abstract | BACKGROUND: METHODS: Four weeks after NTX, rats were put on 3.0% or 0.3% calcium diet for 8 weeks (12-week study). In additional experiments, 15 weeks after NTX, rats were put on similar diets for 12 weeks (27-week study). Appropriate blood, urine, and kidney samples were taken. Renal angiotensin-converting enzyme (ACE) and angiotensin II receptors (AT1, AT2) were examined using autoradiography, ACE also using Western blotting, and connective tissue growth factor (CTGF) using immunohistochemistry. RESULTS: In the 12-week study, albuminuria increased 5-fold in NTX rats, but only 2-fold in calcium NTX rats on 3.0% calcium. In the 27-week study, high calcium intake decreased blood pressure, retarded progression of renal failure, reduced glomerulosclerosis, interstitial damage, and aortic calcifications, and improved survival from 50% to 92% in NTX rats. In both experiments plasma parathyroid hormone and phosphate were elevated after NTX, and suppressed by high calcium diet, while kidney ACE was down-regulated by 40% or more after increased calcium intake. In the 27-week study renal CTGF was decreased and cortical AT1 receptor density reduced after high calcium diet. CONCLUSION: High calcium diet down-regulated kidney ACE, reduced albuminuria and blood pressure, and favorably influenced kidney morphology in experimental renal failure. These findings suggest a link between calcium metabolism and kidney ACE expression, which may play a role in the progression of renal damage.
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Authors | Ilkka Pörsti, Meng Fan, Peeter Kööbi, Pasi Jolma, Jarkko Kalliovalkama, Tuija I Vehmas, Heikki Helin, Harry Holthöfer, Eero Mervaala, Tuulikki Nyman, Ilkka Tikkanen |
Journal | Kidney international
(Kidney Int)
Vol. 66
Issue 6
Pg. 2155-66
(Dec 2004)
ISSN: 0085-2538 [Print] United States |
PMID | 15569305
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- CCN2 protein, rat
- Calcium, Dietary
- Immediate-Early Proteins
- Intercellular Signaling Peptides and Proteins
- Parathyroid Hormone
- Phosphates
- Connective Tissue Growth Factor
- Peptidyl-Dipeptidase A
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Topics |
- Albuminuria
(drug therapy, metabolism, pathology)
- Animals
- Aorta
(pathology)
- Calcium, Dietary
(pharmacology)
- Connective Tissue Growth Factor
- Down-Regulation
(drug effects)
- Immediate-Early Proteins
(metabolism)
- Intercellular Signaling Peptides and Proteins
(metabolism)
- Kidney
(enzymology, pathology)
- Male
- Parathyroid Hormone
(blood)
- Peptidyl-Dipeptidase A
(metabolism)
- Phosphates
(blood)
- Rats
- Rats, Sprague-Dawley
- Renal Insufficiency
(drug therapy, metabolism, pathology)
- Renin-Angiotensin System
(drug effects, physiology)
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