Effects of valsartan on the progression of chronic renal insufficiency in patients with nondiabetic renal diseases.

The present study tested the effects of valsartan, an angiotensin II receptor blocker, on the progression of renal insufficiency in patients with nondiabetic renal diseases. The study subjects were 22 patients with nondiabetic renal diseases whose serum creatinine (Cr) ranged from 1.5 to 3.0 mg/dl. Valsartan (40-80 mg) or placebo was given once daily for 1 year each in a random crossover manner. In both periods, antihypertensive medications were titrated when the blood pressure was not lower than 140/90 mmHg. Blood sampling and urinalysis were performed bimonthly throughout the study periods. The average blood pressure was comparable between the valsartan and the placebo periods (130 +/- 9/86 +/- 6 vs. 131 +/- 8/86 +/- 6 mmHg). Serum Cr significantly increased from 1.9 +/- 0.5 to 2.3 +/- 0.8 mg/dl (p < 0.001) during the placebo period, but the change was insignificant in the valsartan period (2.1 +/- 0.6 to 2.2 +/- 0.9 mg/dl). The slope of decrease in the reciprocal of serum Cr was steeper in the placebo period than in the valsartan period (-0.064 +/- 0.070/year vs. -0.005 +/- 0.050/year, p < 0.01). During the valsartan period, urinary protein excretion was less than that during the placebo period (0.75 +/- 0.73 vs. 1.24 +/- 0.92 g/g Cr, p < 0.001). Serum K was significantly higher in the valsartan period than in the placebo period (4.6 +/- 0.5 vs. 4.4 +/- 0.5 mEq/l, p < 0.05); however, no patients discontinued taking valsartan as a result of hyperkalemia. It is possible that long-term treatment with an angiotensin II receptor blocker, valsartan, is effective at retarding the deterioration of renal function in patients with nondiabetic renal disease by a mechanism independent of blood pressure reduction.

Increased cardiovascular risk in long-term hemodialysis patients carrying deletion allele of ACE gene polymorphism.

BACKGROUND: Controversy continues about the relation of insertion (I)/deletion (D) polymorphism of the angiotensin-converting enzyme (ACE) gene to the genetic predisposition to develop such cardiovascular diseases as myocardial infarction, stroke, and other arteriosclerotic disorders. METHODS: To examine the relation of ACE gene polymorphism to risk for developing cardiovascular diseases in long-term hemodialysis patients, we followed up 534 patients on long-term hemodialysis therapy for 3 years after determining ACE genotype. RESULTS: Numbers of patients with the II, ID, and DD genotypes were 208, 245, and 81, and frequencies of the I and D alleles were 0.62 and 0.38, respectively. Background characteristics, such as age, sex, causative diseases of renal failure, and preexistence of cardiovascular diseases at the time of study entry, were similar among the 3 genotype groups. Serum ACE activity was significantly greater in the DD and ID groups than the II group; however, plasma angiotensin II concentrations were not significantly different among the 3 groups. During the 3 years of follow-up, 46 fatal and 167 nonfatal cardiovascular events occurred. The incidence of these cardiovascular events was significantly associated with older age (P < 0.001), diabetes (P < 0.001), preexistence of cardiovascular diseases (P < 0.001), systolic blood pressure (P = 0.009), high cardiothoracic ratio on chest roentgenogram (P < 0.001), electrocardiographic abnormalities (P < 0.001), and low serum sodium level (P < 0.001). In addition, the incidence of cardiovascular events was greater in patients carrying the D allele (II, 22.1%; ID, 31.8%; DD, 38.3%; P = 0.010). CONCLUSION: It is suggested that the D allele of ACE gene polymorphism is a risk factor for cardiovascular complications in hemodialysis patients.

Microsatellite DNA polymorphism of human adrenomedullin gene in type 2 diabetic patients with renal failure.

BACKGROUND: Adrenomedullin (AM) is a hypotensive peptide widely produced in the cardiovascular organs and tissues such as the heart, kidney, and the vascular cells. We have previously cloned and sequenced the genomic DNA encoding human AM gene, and determined that the gene is located in the short arm of chromosome 11. The 3'-end of the gene is flanked by the microsatellite marker of cytosine adenine (CA) repeats. In this study, we investigated the association between DNA variations in AM gene and the predisposition to develop nephropathy in type 2 diabetes mellitus. METHODS: Genomic DNA was obtained from the peripheral leukocytes of 233 normal healthy subjects (NH), 139 type 2 diabetic patients on hemodialysis (DM-HD), 106 control patients with type 2 diabetes without nephropathy (DM-C) and 318 hemodialysis patients due to chronic glomerulonephritis (CGN-HD). The genomic DNA was subject to polymerase chain reaction (PCR) using a fluorescence-labeled primer, and the number of CA repeats were determined by polyacrylamide gel electrophoresis (PAGE). RESULTS: In our Japanese subjects, there existed four types of alleles with different CA-repeat number; 11, 13, 14, and 19. The frequencies of these alleles were 11: 27.7%, 13: 32.8%, 14: 35.6%, and 19: 3.9% in NH. These allele frequencies were not significantly different in DM-C and CGN-HD. However, DM-HD showed significantly different distribution of allele frequency from other groups (chi 2 = 18.9, P = 0.026). Namely, the frequency of 19-repeat allele in DM-HD was higher (9.0%) than NH, DM-C, and CGN-HD (P = 0.005, 0.041, and 0.004, respectively). CONCLUSION: The microsatellite DNA polymorphism of AM gene may be associated with the genetic predisposition to develop nephropathy in Japanese patients with type 2 diabetes mellitus.

Variations of human adrenomedullin gene and its relation to cardiovascular diseases.

The studies concerning the structure and variations of the human adrenomedullin (AM) gene are reviewed, and their relations to the gene function and genetic predisposition to cardiovascular diseases are discussed. The genomic human AM gene is composed of four exons, and the whole nucleotide sequence corresponding to mature AM resides in the fourth exon. In chromosomal sublocalization, the AM gene is located in the distal portion of the short arm of chromosome 11 (11p15.1-3). Analysis of the promoter region of the AM gene has revealed that two transcription factors, nuclear factor for interleukin-6 expression (NF-IL6) and activator protein 2 (AP-2), participate in the regulation of AM gene expression. It is surmised that NF-IL6 mediates inflammatory stimuli and AP-2 mediates signals of phospholipase C and protein kinase C activation. In addition to these factors, hypoxia induces AM gene expression via the hypoxia inducible factor-1 (HIF-1) binding site. The 3'-end of the AM gene is flanked by a microsatellite marker of cytosine adenine (CA) repeats. In Japanese, there are four types of alleles with different CA-repeat numbers: 11, 13, 14 and 19. It is suggested that existence of the 19-repeat allele is associated with genetic predispositions to develop essential hypertension and diabetic nephropathy.