Overproduction of transforming growth factor-beta 1 (TGF-beta 1) has been implicated in the pathogenesis of fibrotic diseases. TGF-beta 1 plays a crucial role in the accumulation of extracellular matrix (ECM) in human and experimental glomerular diseases. However, it remains unclear whether inhibition of TGF-beta 1 overproduction would suppress TGF-beta 1-induced ECM accumulation. To inhibit the overproduction of TGF-beta 1 in experimental glomerulonephritis induced by anti-Thy 1.1 antibody, we introduced antisense oligodeoxynucleotides (ODN) for TGF-beta 1 into the nephritic kidney by the HVJ-liposome-mediated gene transfer method. Sense, scrambled or reverse ODN were also introduced as controls. Transfected ODN accumulated mainly in the nuclei of mesangial cells in the glomeruli of transfected kidneys. In the antisense ODN-transfected rats, a marked decrease in expression of TGF-beta 1 mRNA was confirmed by Northern analysis. Consequently, the expression of TGF-beta 1 protein in the glomerulus was markedly reduced in the antisense ODN-transfected kidney with a comparable effect in preventing glomerular ECM expansion in experimental glomerulonephritis. In contrast, sense, scrambled and reverse ODNs failed to suppress TGF-beta 1 expression and ECM accumulation. Thus, these results suggested that inhibition of TGF-beta 1 overproduction could suppress progression to glomerulosclerosis.

Solute-free water diuretics (aquaretics) by antagonizing hydrosmotic vasopressin receptors (V2) may be useful in treating water-retaining diseases. The effects ofintravenous administration of a newly developed nonpeptide, selective V2 antagonist, OPC-31260, at doses ranging from 0.017 to 1.0 mg/kg to groups of healthy, normally hydrated men were compared with those of 0.33 mg/kg furosemide and placebo. OPC-31260 increased the hypotonic urine volume dose dependently for the first 4 h, while furosemide induced sodium diuresis for 2 h. The absolute increase in the cumulative response in the urine to the highest doses of OPC-31260 was not significantly different from that to furosemide. The higher doses of OPC-31260 rapidly lowered urine osmolality for 2 h, particularly between minutes 15 and 45 (e.g., 1.0-mg/kg dose: 63±2 mOsm/kg in urine collected between minutes 30 and 45). In a marked hypotonic diuresis, mean free water clearance of the 4-h urine increased dose proportionally into the positive range, reaching 1.80±0.21 ml/min at 1.0 mg/kg. Whereas furosemide induced marked Na and K diuresis, OPC-31260 increased urinary Na excretion only slightly. At 4 h, 0.75 and 1.0 mg/kg of OPC-31260 almost doubled the plasma arginine vasopressin; and the higher doses increased plasma osmolality and plasma Na slightly, but did not alter plasma K, blood pressure, or heart rate. OPC-31260 thus safely induced a potent aquaretic effect in men. (J. Clin. Invest. 1993. 92:2653-2659 Key words: vasopressin antagonist * aquaretic effect * urine osmolality -hyponatremia * arginine vasopressin

The present study demonstrates that (i) apoptosis is involved in the hypertonicity-induced cell death in MDCK cells; (ii) caspase-3, -8, and -9 may contribute to the apoptosis; and (iii) betaine has protective effect on the hypertonicity-induced apoptosis.

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Background: Quick estimation of creatinine clearance from serum without calculation or urine measurements may be useful in many bedside clinical circumstances. A novel formula and a nomogram for predicting creatinine clearance are presented here. Methods: We determined 24-hour creatinine clearance in 155 men and 143 women. A formula for creatinine clearance prediction from serum creatinine (Scr), age, body weight (BVV), and body mass index (BMI) was developed [men: creatinine clearance = (-0.065 Age-0.493BMI + 33)BW/Scr/14.4; women: creatinine clearance = (-0.052 Age-0.202 BMI + 21 )BW/Scr/14.4]. Variables in this formula were evaluated for suitability by multiple regression analysis. The correlation between creatinine clearance measured and creatinine clearance predicted using serum creatinine from the same subject group was high (r = 0.882). A nomogram for creatinine clearance prediction was derived from an equation that included the logarithmic transformation of age, body weight, height, and creatinine excretion instead of the original, nonlogarithmic values. Results: Correlation between measured and estimated creatinine clearance values for the nomogram was slightly lower (r = 0.879) than the r value (0.882) obtained using the original formula. However, the nomogram still has considerable reliability in creatinine clearance prediction compared with several other methods previously reported. Conclusion: The improved formula and nomogram for creatinine clearance presented here show high correlation with measured creatinine clearance. However, almost all the subjects in this study were nondiabetic patients. Therefore, the formula and the nomogram should be applied in treating nondiabetic patients; a separate formula may be needed for patients with diabetic nephropathy.

The effects of hypertonicity on the intracellular amino acid content and system A transport activity were studied in Madin-Darby canine kidney (MDCK) cells. Total content of 20 amino acids increased from 274 to 689 nmol/mg protein after 8 h of hypertonicity (500 mosmol/ kg), remaining almost constant until after 6 days of hypertonicity. The content of neutral amino acids increased from 77 to 307 and 395 nmol/mg protein after 8 h and 6 days of hypertonicity, respectively, accounting for 73% of the increased amount of total amino acids. In the hypertonic MDCK cells, system A transport activity, measured by Na+-dependent 2-(methylamino)isobutyric acid (MeAIB) uptake, increased approximately 60-fold relative to the uptake in isotonic cells. MeAIB was taken up primarily on the basal side in the isotonic MDCK cells cultured on permeable supports. Extracellular hypertonicity stimulated the MeAIB uptake predominantly on the basal side. These results indicated that amino acids, especially neutral amino acids, can function as volume-regulating osmolytes and that the stimulation of system A activity appears to contribute to the accumulation of neutral amino acids in hypertonic MDCK cells.

The effect of the change from supine to upright position on GFR (measured by creatinine clearance) was studied in nonazotemic patients with biopsy-proven primary glomerulonephritis. Compared to healthy subjects, the fall in GFR following the postural change was significantly larger in patients with mesangial proliferation (MP) and with both MP and thickening of glomerular capillary wall (GCW), while similar in those with thickening of GCW alone, suggesting that MP, but not thickening of GCW, augments posturally induced fall in GFR. The augmented fall in GFR in patients with MP was accompanied by larger fall in GFR per unit increase in plasma renin activity than in healthy subjects, and was eliminated by angiotensin-converting enzyme inhibition. We conclude that MP augments posturally induced fall in GFR through affecting glomerular reactivity to angiotensin II.

The metabolic pathway of methylguanidine (MG) is mainly speculated from the change in urinary excretion of MG in the arginine (Arg)-injected normal rat, the creatinine (Cr)-injected normal rat, and the Arg-injected uremic rat. ¹⁵N-Arg was ingested to 2 uremic patients. Arg administration resulted in marked increase in urinary MG excretion both in the uremic rat and patient, but not in the normal rat. In the first phase of the ¹⁵N-Arg ingestion experiment, a rapid rise of ¹⁵N atom percent excess of urinary MG was observed in the uremic patient. In the second phase of this study, after 24 h of ¹⁵N-Arg ingestion, the ¹⁵N atom percent excess of urinary Cr and that of MG closely paralleled. These findings imply that there might be two metabolic origins of MG: one is a formation of MG from Arg itself or an Arg metabolite other than Cr, the other a pathway producing MG via Cr. The former is compatible with the hypothesis by Cohen.