Fosinopril/hydrochlorothiazide: single dose and steady-state pharmacokinetics and pharmacodynamics.
(25/1788)
AIMS: Fosinoprilat, the active product of fosinopril, is eliminated by an hepatic pathway in addition to the renal pathway shared by other angiotensin converting enzyme inhibitors (ACEIs). This study aimed to determine whether impaired renal function affects the pharmacokinetics and pharmacodynamics of a combination of fosinopril and hydrochlorothiazide (HCTZ). METHODS: The study had a parallel-group design comparing patients with renal impairment and body-mass-index-matched normal controls. The study was done in a University clinic in 13 patients with renal impairment (mean creatinine clearance 55.7+/-15.6 ml min-1 1.73 m-2 ) and 13 age-, sex-, and body-mass-index-matched normal controls (mean creatinine clearance 102.4+/-8.9 ml min-1 1.73 m-2 ). All patients and normal controls received fosinopril sodium 20 mg and HCTZ 12.5 mg as a daily oral administration on days 1-5. Non-compartmental pharmacokinetic parameters of fosinoprilat and HCTZ were determined from blood and urine samples obtained over 48 h starting on Day 1 (single dose) and Day 5 (steady state): maximum serum concentration (Cmax ), time to maximum serum concentration (tmax ), area under the serum concentration-time curve during the dosing interval (AUC), cumulative urinary excretion (CUE) and the accumulation index (AI; ratio of AUC-day 5/AUC-day 1). Pharmacodynamic parameters were also measured over 24 h on day 1 and over 48 h on day 5: serum ACE activity and arterial blood pressure. RESULTS: Fosinoprilat pharmacokinetic parameters on day 1 in renally impaired vs normal patients: Cmax=387+/-0.19 vs 324+/-0.25 ng ml-1 (P=0.07); tmax=3.5 vs 3.0 h (P=0.58); AUC=3510+/-0.29 vs 2701+/-0.35 ng ml-1 h (P=0. 072); CUE=5.08+/-2.70 vs 7.40+/-2.56% (P=0.009). Fosinoprilat parameters on day 5: Cmax=517+/-0.40 vs 357+/-0.19 ng ml-1 (P=0. 007); tmax=3.0 vs 3.0 h (P >0.99); AUC=4098+/-0.43 vs 2872+/-0.30 ng ml-1 h (P=0.027); CUE=6.81+/-3.53 vs 8.10+/-2.80% (P=0.068). AI=1. 17+/-0.33 vs 1.06+/-0.23 (P=0.29). In both groups ACE inhibition and blood pressure response were similar over 24 h and slightly greater 48 h after last dosing. CONCLUSIONS: In renally impaired subjects fosinopril and HCTZ can be coadministered without undue increases in fosinoprilat concentrations or any clinically significant pharmacodynamic effects. This is probably due to the dual excretory pathways for fosinoprilat. (+info)
Effect of cyclooxygenase-2 inhibition on renal function after renal ablation.
(26/1788)
Kidney failure is the common end of hypertension and renal diseases. Several authors have suggested that vasodilatory prostaglandins participate in the hemodynamic mechanism responsible for the development of kidney failure. However, the mechanism by which prostaglandins are increased in renal disease is not clear. Recently, 2 isoforms of the enzyme responsible for prostaglandin synthesis, cyclooxygenase, have been described as cyclooxygenase-1 (COX-1), a constitutive isoform, and cyclooxygenase-2 (COX-2), an inducible isoform. In the present study, we investigated whether COX-2-dependent prostaglandins participate in the evolution of renal functional changes after renal ablation. We inhibited prostaglandin synthesis by COX-1 and COX-2 with indomethacin (3 mg/kg) and prostaglandin synthesis by COX-2 with NS-398 (3 mg/kg) and tested the effect of these inhibitors on the renal functional changes elicited by renal ablation. Renal ablation produced an increase in urinary volume, protein, and prostaglandin E(2), whereas urinary sodium and potassium were not affected and urinary osmolarity decreased; treatment with indomethacin or NS-398 partially prevented the renal functional changes elicited by renal ablation. Immunoblots for COX showed an increase in the expression of COX-2 protein 2 days after renal ablation. Furthermore, COX-2 mRNA expression was increased 1 day after renal ablation. These data suggest that COX-2-dependent prostaglandins participate in the renal mechanisms associated with the development of renal functional changes after renal ablation. (+info)
N(epsilon)-(carboxymethyl)lysine adducts of proteins are ligands for receptor for advanced glycation end products that activate cell signaling pathways and modulate gene expression.
(27/1788)
Recent studies suggested that interruption of the interaction of advanced glycation end products (AGEs), with the signal-transducing receptor receptor for AGE (RAGE), by administration of the soluble, extracellular ligand-binding domain of RAGE, reversed vascular hyperpermeability and suppressed accelerated atherosclerosis in diabetic rodents. Since the precise molecular target of soluble RAGE in those settings was not elucidated, we tested the hypothesis that predominant specific AGEs within the tissues in disorders such as diabetes and renal failure, N(epsilon)-(carboxymethyl)lysine (CML) adducts, are ligands of RAGE. We demonstrate here that physiologically relevant CML modifications of proteins engage cellular RAGE, thereby activating key cell signaling pathways such as NF-kappaB and modulating gene expression. Thus, CML-RAGE interaction triggers processes intimately linked to accelerated vascular and inflammatory complications that typify disorders in which inflammation is an established component. (+info)
Evaluation of renal function in elderly heart failure patients on ACE inhibitors.
(28/1788)
A total of 187 heart failure patients aged 65-92 years, with pretreatment serum creatinine levels below 200 mumol/l, were monitored for more than 12 months on angiotensin-converting enzyme (ACE) inhibitor therapy. Optimal ACE inhibitor dosage was found in 27% of patients, while a significant deterioration in renal function, characterised by > 20% increase in serum creatinine to > 200 mumol/l, occurred in 25 patients. This was most closely attributable to ACE inhibitor treatment per se (implying co-existence of bilateral renal artery stenosis) in only four cases, including one in whom renal deterioration was reproducible on inadvertent rechallenge. In the other 21, renal deterioration was attributable to diuretic-related blood volume depletion (two cases), nonsteroidal anti-inflammatory drugs (two cases), obstructive uropathy (two cases), preterminal renal shutdown (two cases), and the interaction between diuretic and ACE inhibitor dosage (including long-acting vs short-acting drugs) (13 cases). This study could serve as the basis for future comparisons of ACE-inhibitor-related renal deterioration when the entry requirement is optimal ACE inhibitor dosage. (+info)
Cholesterol embolism in a patient with inflammatory abdominal aortic aneurysm.
(29/1788)
A 66-year-old man whose renal function had progressively deteriorated had an elevated blood pressure and also was found to have an inflammatory abdominal aortic aneurysm (AAA). Blood examination revealed that he had eosinophilia. Livedo reticularis of the toes developed, and a skin biopsy specimen showed embolization of atheromatous plaques in the arterioles of the subcutaneous tissue. Progressive enlargement of inflammatory AAA may have dislodged the atheromatous plaques, resulting in cholesterol embolism. (+info)
Primary renal hypoplasia in humans and mice with PAX2 mutations: evidence of increased apoptosis in fetal kidneys of Pax2(1Neu) +/- mutant mice.
(30/1788)
PAX2 mutations cause renal-coloboma syndrome (RCS), a rare multi-system developmental abnormality involving optic nerve colobomas and renal abnormalities. End-stage renal failure is common in RCS, but the mechanism by which PAX2 mutations lead to renal failure is unknown. PAX2 is a member of a family of developmental genes containing a highly conserved 'paired box' DNA-binding domain, and encodes a transcription factor expressed primarily during fetal development in the central nervous system, eye, ear and urogenital tract. Presently, the role of PAX2 during kidney development is poorly understood. To gain insight into the cause of renal abnormalities in patients with PAX2 mutations, kidney anomalies were analyzed in patients with RCS, including a large Brazilian kindred in whom a new PAX2 mutation was identified. In a total of 29 patients, renal hypoplasia was the most common congenital renal abnormality. To determine the direct effects of PAX2 mutations on kidney development fetal kidneys of mice carrying a Pax2 (1Neu)mutation were examined. At E15, heterozygous mutant kidneys were approximately 60% of the size of wild-type littermates, and the number of nephrons was strikingly reduced. Heterozygous 1Neu mice showed increased apoptotic cell death during fetal kidney development, but the increased apoptosis was not associated with random stochastic inactivation of Pax2 expression in mutant kidneys; Pax2 was shown to be biallelically expressed during kidney development. These findings support the notion that heterozygous mutations of PAX2 are associated with increased apoptosis and reduced branching of the ureteric bud, due to reduced PAX2 dosage during a critical window in kidney development. (+info)
Enhanced reduction of fasting total homocysteine levels with supraphysiological versus standard multivitamin dose folic acid supplementation in renal transplant recipients.
(31/1788)
The mild fasting hyperhomocysteinemia commonly observed in chronic (ie, >/=6 months posttransplantation) renal transplant recipients (RTRs) can be effectively treated with combined B-vitamin supplementation featuring supraphysiological doses of folic acid. There are no controlled data evaluating the comparative efficacy of supraphysiological versus standard multivitamin dose folic acid supplementation in reducing fasting total homocysteine (tHcy) levels among RTRs. We block-randomized 60 chronic, stable RTRs on the basis of their screening fasting tHcy level to 3 groups of 20 subjects treated for 12 weeks with folic acid at either 2.4 (group 1), 0.4 (ie, standard multivitamin dose) (group 2), or 0.0 (group 3) mg/d. All 60 study participants also received 50 mg/d vitamin B(6) and 0.4 mg/d vitamin B(12). The mean percent reductions (+/-SEM) in fasting tHcy were as follows: group 1, 32.3+/-2.4%; group 2, 23.4+/-2.3%; and group 3, 19.1+/-2.3%. ANCOVA accounting for the pretreatment matching and adjusted for pretreatment levels of fasting tHcy, folate, and albumin; change in creatinine during the study; and cyclosporine A use revealed significant overall group differences (P=0.005) and significant differences between groups 1 and 2 (P=0. 038) and groups 1 and 3 (P=0.001), but not between groups 2 and 3 (P=0.153). Moreover, a chi(2) analysis of participants with pretreatment tHcy levels >/=15 micromol/L (n=29) indicated that a significantly greater proportion of those in group 1 achieved posttreatment levels <12 micromol/L: group 1, 5 of 10 (50%); group 2, 1 of 11 (9%); and group 3, 0 of 8 (0%) (P=0.016; test of trend P=0. 007). We conclude that a supraphysiological dose of folic acid is superior to standard multivitamin dosing for the reduction of fasting tHcy levels in chronic RTRs. (+info)
22-Oxacalcitriol ameliorates high-turnover bone and marked osteitis fibrosa in rats with slowly progressive nephritis.
(32/1788)
22-Oxacalcitriol ameliorates high-turnover bone and marked osteitis fibrosa in rats with slowly progressive nephritis. BACKGROUND: 22-Oxacalcitriol (OCT) is a unique vitamin D analogue with less calcemic activity than calcitriol, and it effectively suppresses parathyroid hormone (PTH) secretion in uremic rats. This study was performed to examine the long-term effect of intravenously administered OCT on high-turnover bone disease in model rats of slowly progressive renal failure. METHODS: Slowly progressive renal failure rats were made by a single injection of glycopeptide isolated from rat renal cortical tissues. At 250 days, glycopeptide-induced nephritis (GN) rats were divided into three groups with the same levels of serum creatinine and PTH, and they received either OCT (0.03 or 0.15 microg/kg body wt) or vehicle given intravenously three times per week for 15 weeks. RESULTS: Renal function of GN rats deteriorated very slowly but progressively, as assessed by the increase of serum creatinine concentration. At sacrifice, serum PTH levels, bone formation markers, bone resorption markers, and fibrosis volume were significantly elevated in vehicle-treated GN rats compared with those of sham-operated rats, suggesting the development of high-turnover bone disease with osteitis fibrosa. In contrast, in the GN-OCT 0.15 microg/kg group, these high PTH levels and high-turnover bone and fibrosis were significantly decreased. Such amelioration of bone abnormalities by OCT was not accompanied by either hypercalcemia or further deterioration of renal function. CONCLUSIONS: These data indicate that OCT may be a useful and safe agent not only for the suppression of PTH, but also for the amelioration of osteitis fibrosa and high-turnover bone without causing hypercalcemia in chronic dialysis patients. (+info)