Intravenous Maxacalcitol Therapy Correlates with Serum Fibroblast Growth Factor 23 Levels in Hemodialysis Patients Independent of Serum Phosphate or Calcium Levels.

Fibroblast growth factor 23 (FGF23) is a regulator of phosphate and vitamin D homeostasis that carries out primary bone- and mineral-related physiological functions to increase renal phosphate excretion and reduce 1α-hydroxylation of 25-hydroxyvitamin D. In a negative endocrine feedback loop, 1,25-dihydroxyvitamin D also stimulates FGF23 secretion. Previous studies have assessed the correlation between vitamin D receptor activator therapy and FGF23 concentrations, and to our knowledge, none has assessed the correlation between intravenous (i.v.) maxacalcitol therapy and FGF23 concentration in hemodialysis patients. Subjects included 148 patients on maintenance hemodialysis. Serum FGF23 concentrations were measured. The correlations among serum FGF23 concentrations with i.v. maxacalcitol therapy and other clinical parameters and medications were analyzed. Mean serum log FGF23 was 3.7 ± 0.8 pg/mL. After division into two equal groups based on median serum log FGF23 level, the percentages of patients administered i.v. maxacalcitol (60/74 [81.1%] vs. 45/74 [60.8%], p < 0.01) were significantly higher in the high log FGF23 group. The amounts of serum FGF23 concentrations had been significantly higher to the amounts of i.v. maxacalcitol per week dependency. Multivariate regression analysis showed that treatment with i.v. maxacalcitol was an independent predictor of serum FGF23 levels, regardless of phosphate or calcium concentrations. i.v. maxacalcitol correlates with serum FGF23 concentration in hemodialysis patients, independent of serum phosphate or calcium concentrations.

Renal protective effects of pitavastatin on spontaneously hypercholesterolaemic Imai Rats.

BACKGROUND: Independent of their lipid-lowering effects, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors have renal protective effects on various models of progressive renal diseases, therefore, additional therapeutic advantages have been considered. In the present study, using spontaneously hypercholesterolaemic Imai rats, we examined the protective effects of pitavastatin on renal injuries and the oxidative modification of the low-density lipoprotein (LDL) and high-density lipoprotein (HDL), since oxidized lipoproteins are speculated to be involved in the mechanism of this rat strain's renal injuries. METHODS: Male Imai rats were treated with pitavastatin (n = 11) at a dose of 100 mg/kg diet or received no specific therapy as controls (n = 11) from 10 to 22 weeks of age. Body weight, urinary protein excretion and serum constituents were evaluated every 4 weeks. At the end of the study, the effects of pitavastatin on the susceptibility of serum LDL and HDL to oxidation, and renal histology were examined. RESULTS: Pitavastatin treatment did not affect hyperlipidaemia, but significantly reduced proteinuria and preserved creatinine clearance deterioration. At the end of the study, lag times for LDL and HDL oxidation were prolonged by the treatment of pitavastatin to 126 and 153%, respectively, compared with the controlled group. The glomerulosclerosis index (SI) for untreated controlled rats was significantly higher than that for the pitavastatin-treated group. An immunohistochemistry study showed significantly lower numbers of ED-1 positive macrophages in the glomeruli and interstitium in pitavastatin-treated rats compared with those controlled. CONCLUSION: Pitavastatin treatment prevented renal injuries in Imai rats independent of lipid-lowering effects. Prevention of oxidative modification of LDL and HDL may play an important role on the beneficial effects of pitavastatin treatment.

Various dietary protein intakes and progression of renal failure in spontaneously hypercholesterolemic Imai rats.

BACKGROUND/AIM: Dietary protein restriction is known to be beneficial in the preservation of the renal function in patients with chronic renal failure. Recently, the effect of varying quantity and quality of dietary protein intakes was also studied. This study investigates the effects of different dietary animal proteins on renal function in spontaneously hypercholesterolemic Imai rats that exhibit renal lesions similar to human focal and segmental glomerulosclerosis. The sources of proteins were from casein, pork, and fish. Primary concern was the effect of fish meat protein, because the effects of fish oil are well reported. To examine whether remnants of fish oil affect the experimental results, semi-defatted fish meat and fully defatted fish meat were prepared for these experiments. METHODS: Forty-two Imai rats were placed on diets containing casein, defatted pork meat, semi-defatted fish meat, or defatted fish meat as a protein sources from 10 to 22 weeks of age. Twenty-four hour urine collections were obtained along with measurements of systolic blood pressure and drawing blood from the tail artery every 4 weeks. Finally, the kidneys were removed and prepared for histological study. RESULTS: The semi-defatted fish meat diet retarded the rise of plasma cholesterol, virtually completely prevented the development of hypertriglyceridemia, and slowed the progression of proteinuria, renal function failure, and glomerular injury as compared with the control casein diet. However, the fully defatted fish meat diet led to renal failure at the same rate as the casein diet. The defatted pork diet group exhibited a higher creatinine clearance at the end of the experiments as compared with the casein and the fully defatted fish meat diet groups. CONCLUSIONS: These data suggest that an important determinant of the protective effects of the semi-defatted fish meat diet was related to the prevention of hypercholesterolemia and hypertriglyceridemia by the remaining fish oil. Fish meat protein itself did not indicate superior beneficial effects in the regression of the renal function in Imai rats as compared with casein protein, and defatted pork showed better results than casein and fully defatted fish meat.

[Long-term suppressive effect of falecalcitriol on parathyroid hormone secretion in secondary hyperparathyroidism in hemodialysis patients].

Alfacarcidol and calcitriol are widely used to treat secondary hyperparathyroidism associated with chronic renal failure, but it is often not possible to administer doses high enough to sufficiently inhibit parathyroid hormones because of the risk of hypercalcemia and hyperphosphatemia. We administered falecalcitriol (Hornel) Tablets) to patients with poorly controlled secondary hyperparathyroidism. The usefulness of falecalcitriol was demonstrated by the fact that control of intact-PTH was maintained for up to 24 months without a clear increase in serum Ca x serum inorganic phosphorus (iP), iP, and ALP levels.

[Levels of serum ascorbate and its metabolites in hemodialysis patients].

The status of ascorbic acid (AA) in dialysis patients is the subject of debate. Some reports have found AA to be deficient in dialysis patients, while others have found that AA is not deficient. In an attempt to confirm AA serum concentrations in dialysis patients, we analyzed the concentrations of AA as well as its metabolites using the specific determination of AA with chemical derivatization and the HPLC method. We studied 131 patients under maintenance hemodialysis therapy (HD), 23 patients with chronic renal failure (CRF) and 48 healthy controls (C). Serum concentrations of AA and the AA metabolites dehydroascorbic acid (DHA) and 2, 3-diketogulonate (DKG) were measured by HPLC. Nine HD patients were taking AA supplements. Seventy-six (62.3%) of the 122 HD patients not taking AA supplements exhibited deficient levels of AA (< 20 microM), while 13 (56.5%) of the 23 CRF patients and 9 (18.8%) of the 48 C showed deficient levels of AA. Analysis of AA metabolites in the normal-range AA (20-80 microM) group revealed that the DHA/AA ratio in HD patients was significantly higher than in C (3.3 +/- 2.6% and 1.2 +/- 2.2%, respectively). The DKG/AA ratio in HD patients was higher than in CRF patients (3.6 +/- 5.2% vs. 0.9 +/- 1.9%), whereas DKG was not detected in C. When compared to serum levels before the start of dialysis, serum AA, DHA and DKG concentrations at the end of the dialysis session decreased by an average of 74.2, 84.0 and 78.8% respectively. In HD patients, serum levels of thiobarbituric reactive substances (TBARS) were significantly lower in the higher AA (> 80 microM) group than in the deficient and normal-range AA groups. In 12 AA-deficient patients, after 1 month of taking AA supplements (200 mg/day), serum AA levels rose to 79.9 microM, while serum TBARS level declined when compared with levels before supplementation. In conclusion, the frequency of AA deficiency in dialysis patients is extremely high. AA deficiency in HD patients may result in high TBARS levels, which reflect increased oxidative stress. Adequate AA supplementation should therefore be considered in such patients.