sodium-bicarbonate and Proteinuria

Sodium bicarbonate (NaHCO

Topics: Acids; Animals; Blood Glucose; Disease Models, Animal; Fibrosis; Glomerulosclerosis, Focal Segmental; Hemodynamics; Hydrogen-Ion Concentration; Ion Channels; Kidney Tubules; Male; Proteinuria; Rats, Inbred Dahl; Rats, Mutant Strains; Sodium Bicarbonate; Sodium Chloride, Dietary

The roles of the kidney are well defined, if there is a progressive loss in renal function, the kidney is no longer able to perform the listed tasks and chronic kidney disease (CKD) persists. In both clinical and experimental studies, NaHCO

Topics: Animals; Glomerular Filtration Rate; Kidney Glomerulus; Proteinuria; Rats; Rats, Inbred Dahl; Renal Insufficiency, Chronic; Sodium Bicarbonate

A highly acidic environment surrounds proximal tubular cells as a result of their reabsorption of HCO(3)(-). It is unclear whether this luminal acidity affects proteinuria-induced progression of tubular cell damage. Here, we investigated the contribution of luminal acidity to superoxide (O(2)(·-)) production induced by oleic acid-bound albumin (OA-Alb) in proximal tubular cells. Acidic media significantly enhanced OA-Alb-induced O(2)(·-) production in the HK-2 proximal tubular cell line. Simultaneous treatment with both OA-Alb and acidic media led to phosphorylation of the intracellular pH sensor Pyk2. Highly phosphorylated Pyk2 associated with activation of Rac1, an essential subcomponent of NAD(P)H oxidase. Furthermore, knockdown of Pyk2 with siRNA attenuated the O(2)(·-) production induced by cotreatment with OA-Alb and acid. To assess whether luminal alkalinization abrogates proteinuria-induced tubular damage, we studied a mouse model of protein-overload nephropathy. NaHCO(3) feeding selectively alkalinized the urine and dramatically attenuated the accumulation of O(2)(·-)-induced DNA damage and proximal tubular injury. Overall, these observations suggest that luminal acidity aggravates proteinuria-induced tubular damage and that modulation of this acidic environment may hold potential as a therapeutic target for proteinuric kidney disease.

Topics: Albumins; Animals; Apoptosis; Cell Line; Disease Models, Animal; Disease Progression; DNA Damage; Female; Focal Adhesion Kinase 2; Humans; Hydrogen-Ion Concentration; Kidney Diseases; Kidney Tubules, Proximal; Male; Mice; Mice, Inbred C57BL; NADPH Oxidases; Oleic Acid; Oxidative Stress; Oxygen; Proteinuria; Reactive Oxygen Species; Sodium Bicarbonate

Rat urinary protein concentration is commonly measured during safety assessment studies to evaluate potential drug-induced nephrotoxicity. It has been reported that impregnated reagent test strips (dipsticks) can yield false-positive urinary protein results for alkaline urine samples.. The objective of this study was to determine if urinary dipsticks accurately assess protein concentrations, especially in alkaline rat urine.. Ten male Sprague-Dawley rats were treated with 2% sodium bicarbonate and 2% ammonium chloride to alkalinize and acidify the urine, respectively. Urine pH was measured in treated and control rats using a pH meter and urinary dipsticks with the Clinitek 500. Quantitative urinary protein results were compared to urinary dipstick protein evaluations obtained with the Clinitek 500 and sulfosalicylic acid precipitation test methods.. The urinary dipstick pH measurement had a very high correlation (r = .98) with the pH meter technique. Samples with alkaline pH (>or=7.5) analyzed for protein by dipstick analysis were in complete agreement 34.7% of the time with the quantitative technique, which was very similar to the 39.3% agreement for samples with neutral and acidic pH (

Topics: Ammonium Chloride; Animals; Hydrogen-Ion Concentration; Male; Proteinuria; Rats; Rats, Sprague-Dawley; Reagent Strips; Sodium Bicarbonate; Urinalysis; Urine

With longer graft and patient survival, recurrent disease is becoming recognized as an increasingly important contributor to long-term graft loss in renal transplant recipients. However, patients may present for the first time in end-stage renal disease (ESRD) leading to uncertainty as to their underlying diagnosis and the risk of recurrence. The purpose of this study was to describe the features of children who presented for the first time in ESRD and to determine the predictive value of investigations in differentiating diseases with and without a recurrence risk. From 7/99 to 11/04, 13 children presented to our center in ESRD. Their median age was 13.3 yr; 77% were male. The majority were hypertensive (77%) and oligoanuric (69%). All had proteinuria (median urine protein to creatinine ratio [Up/c] 7.0), and 92% had microhematuria. Only seven had small kidneys on ultrasound. All children underwent a serologic work-up and six (46%) were biopsied. Of the 13 children, seven had a glomerular disease; in five the diagnosis was made on biopsy, in one on serologic testing and one by family history. Of the remaining six children, three had non-glomerular diseases: obstructive uropathy in one and primary hyperoxaluria type 1 in two, and 3 had an unknown disease. When patients with glomerular diseases were compared with those with non-glomerular diseases, the two predictors for glomerular disease were a lower serum albumin (p = 0.004) and a higher serum bicarbonate level (p = 0.01). Comparing patients with and without a risk of recurrence, there were no differences between the two groups in any of their demographic, clinical, or biochemical parameters by analysis of variance (including serum albumin or proteinuria). In summary, the vast majority of children presenting in ESRD have hematuria and proteinuria, even with non-glomerular diseases. The significant overlap in clinical features between patients with and without a risk of recurrence emphasizes the need for all children presenting in ESRD to be evaluated extensively so that disease recurrence after transplantation can be anticipated or even prevented.

Topics: Adolescent; Female; Hematuria; Humans; Kidney Failure, Chronic; Kidney Transplantation; Male; Predictive Value of Tests; Proteinuria; Recurrence; Retrospective Studies; Risk Factors; Serum Albumin; Sodium Bicarbonate; Treatment Outcome

The presence of plasma proteins in the tubular lumen has variety of adverse effects on the tubular cells. Among various plasma proteins filtered through glomerular barrier, complement has been proven as the possible candidate inducing tubulointerstitial injury. To study the role of intratubular complement activation in proteinuric patients, complement activation products (CAP) at C3 level (iC3b and Bb) and C9 level (membrane attack complex) were measured in both plasma and urine of patients with minimal change nephrotic syndrome (MCNS), focal glomerular sclerosis, IgA nephropathy, membranous nephropathy, and diabetic nephropathy. For evaluation of the effect of metabolic acidosis on the intratubular complement activation, urinary CAP were measured before and after sodium bicarbonate administration in patients with renal insufficiency. The following results were obtained: (1) Patients with focal glomerular sclerosis and diabetic nephropathy showed the highest level of urinary CAP excretion rate (unit/creatinine), while MCNS revealed no increase. (2) Patients with membranous nephropathy showed a unique finding, i.e., isolated increase of membrane attack complex excretion. (3) There was no significant correlation between urine and plasma levels of CAP. (4) Except for MCNS patients, the urinary excretion rate of CAP significantly increased when the level of proteinuria exceeded the nephrotic range, and it was significantly correlated with the serum creatinine level. (5) Urinary CAP excretion rate significantly decreased 2 wk after sodium bicarbonate administration without affecting the level of proteinuria or plasma CAP. These results suggest that the degree of intratubular complement activation correlates with the level of proteinuria, type of glomerular disease, impairment of renal function, and metabolic acidosis.

Topics: Adolescent; Adult; Aged; Blotting, Western; Complement Activation; Complement C3b; Complement Membrane Attack Complex; Female; Humans; Kidney; Kidney Diseases; Male; Middle Aged; Proteinuria; Reference Values; Sodium Bicarbonate

In nephrotic syndrome, significant amounts of plasma proteins, mostly of hepatic origin, are lost in urine. Total hepatic protein synthesis increases, suggesting that other protein pools must be conserved to maintain steady state. This can be accomplished either by decreased amino acid oxidation or decreased protein synthesis in other organs to replace lost liver-derived proteins. To determine the effect of nephrotic syndrome on total-body protein metabolism, we compared whole-body valine use in seven nephrotic patients and five controls using a primed continuous infusion of [1-(13)C]-valine, with additional priming of NaH(13)CO(3). Plasma [(13)C]-valine, (13)C alpha ketoisovaleric acid, and the expired (13)CO(2) enrichments were used to assess whole-body valine flux, valine oxidation, and nonoxidative valine disposal (NOVD). The valine flux into the blood compartment (97.7 +/- 3.0 versus 95.3 +/- 3.3 micromol/kg/h), oxidation of valine (19.4 +/- 1.9 versus 21.2 +/- 2. 8 micromol/kg/h), and NOVD (78.3 +/- 2.5 versus 74.2 +/- 2.7 micromol/kg/h) were not statistically different in patients compared with controls. Valine oxidation correlated positively with urinary urea excretion (r = 0.70; P = 0.01) in all subjects. Compared with control subjects who have similar urinary urea excretion, nephrotic subjects do not compensate for urinary loss of protein by decreased amino acid oxidation or decreased nonoxidative valine disposal. Previous studies have shown that synthesis of several hepatic proteins increases when subjects are fed the same dietary regime, whereas the present study shows that total-body protein synthesis does not increase. This would imply reduced synthesis of nonhepatic protein pools.

Topics: Adult; Amino Acids; Blood Proteins; Carbon Dioxide; Carbon Isotopes; Creatinine; Female; Hemiterpenes; Humans; Infusions, Intravenous; Keto Acids; Linear Models; Liver; Male; Middle Aged; Nephrosis; Oxidation-Reduction; Pentanoic Acids; Protein Biosynthesis; Proteinuria; Serum Albumin; Sodium Bicarbonate; Urea; Valerates; Valine

Oral sodium bicarbonate (NaHCO3) is widely used to treat acidosis in patients with renal failure. However, no data are available in man on the effects on proximal renal tubular protein catabolism or markers of tubular injury. We have developed methods to allow such studies, and both increased tubular catabolism of 99mTc-labelled aprotinin (Apr*), as well as tubular damage were found in association with increased ammonia (NH3) excretion in patients with nephrotic range proteinuria. We now examine the effects of reducing renal ammoniogenesis, without altering proteinuria, using oral NaHCO3 in 11 patients with mild/moderate renal impairment and proteinuria. Renal tubular catabolism of Apr* was measured before and after NaHCO3 by renal imaging (Kidney uptake, K% of dose) and urinary excretion of free 99mTcO4- (metabolism, Met% of dose/h) over 26 h. Fractional degradation (Frac) was calculated from Met/K (/h). Fresh urine was also analyzed for NH3 excretion every fortnight from 6/52 before treatment. Total urinary N-acetyl-beta-D-glucose-aminidase (NAG) and the more tubulo-specific NAG "A2" were measured. 51CrEDTA clearance and 99mTc-MAG 3 TER were also assessed. After NaHCO3 Met over 26 h was significantly reduced (from 1.3 +/- 0.2% of dose/h to 0.9 +/- 0.1% dose/hr, p < 0.005), as was Frac of Apr* (from 0.06 +/- .006/h to 0.04 +/- 0.005/hr, p < 0.003). NH3 excretion also fell significantly (from 0.9 +/- 0.2 mmol/h to 0.2 +/- 0.05 mmol/h, p < 0.007), as did both total urinary NAG (from 169 mumol/24 h, 74-642 mumol/24 h to 79 mumol/ 24 h, 37-393 mumol/24 h, p < 0.01), and the NAG 'A2' isoenzyme (from 81.5 mumol/24 h, 20-472 mumol/24 h to 35.0 mumol/24 h, 6-388 mumol/24 h, p < 0.001). Proteinuria remained unaltered, and there was no change in blood pressure nor in glomerular haemodynamics. Oral NaHCO3 may thus pro-tect the proximal renal tubule and help delay renal disease progression.

Topics: Acetylglucosaminidase; Administration, Oral; Adult; Ammonia; Aprotinin; Blood Pressure; Chromium Radioisotopes; Edetic Acid; Female; Humans; Hydrogen-Ion Concentration; Kidney Failure, Chronic; Kidney Tubules, Proximal; Male; Middle Aged; Nephelometry and Turbidimetry; Organotechnetium Compounds; Proteinuria; Radionuclide Imaging; Radiopharmaceuticals; Sodium Bicarbonate

One of the major complications after high-dose methotrexate (HDMTX) infusions is renal damage. We investigated the occurrence of proteinuria after HDMTX administration in children with pediatric malignancies (acute lymphoid leukaemia, osteosarcoma Burkitt's lymphoma). In the period 1989-1990 we gave 52 HDMTX courses to 24 children. During this period, prehydration and extra urinary alkalisation were performed only if the urinary specific gravity was over 1010 or if the urinary pH fell below 7. Using this schedule the mean values obtained for protein extraction were: before the therapy, 0.12 +/- 0.03 g/m2; on day 1 after MTX treatment, 0.38 +/- 0.06 g/m2; and on day 2 after the MTX infusion, 0.39 +/- 0.11 g/m2 (P < 0.01). A significant increase in proteinuria (> 0.2 g/m2 post- vs pretreatment) was detectable in 54% of the patients. In the period 1991-1992 we modified the hydration-alkalisation schedule to include i.v. prehydration for 18-24 h at 3 l/m2/day with a 0.45% NaCl-5% glucose solution along with sodium bicarbonate and posthydration for 72 h with the same solution. On this protocol the mean values determined for the urinary protein content were all in the normal range (pretreatment, 0.03 g/m2/day; day 1, 0.05 g/m2/day; and day 2, 0.08 g/m2/day). These findings were significantly different from the previous results (P < 0.05).

Topics: Adolescent; Bone Neoplasms; Burkitt Lymphoma; Child; Female; Fluid Therapy; Glomerular Filtration Rate; Glucose; Humans; Male; Methotrexate; Neoplasms; Osteosarcoma; Precursor Cell Lymphoblastic Leukemia-Lymphoma; Proteinuria; Sodium Bicarbonate

Topics: Bicarbonates; Humans; Infant; Male; Proteinuria; Sodium; Sodium Bicarbonate

Infusion of an acidic amino acid, L-aspartate, to 10 volunteers resulted in transient, significant increases in urinary excretion of the major urinary trypsin inhibitor (p less than 0.002) and beta 2-microglobulin (p less than 0.02). Simultaneously with the proteinuria, urinary pH rose significantly (p less than 0.02). These changes appeared following the infusion and after the excretion of L-aspartate had reached the preinfusion level. Albumin excretion was unchanged indicating that the proteinuria was due to a decreased tubular reabsorption. The mechanism for the reversible tubular proteinuria is unknown. A simple pH effect due to alkalization of the urine was excluded, as NaHCO3 infusion was not followed by an increase in the excretion of the major urinary trypsin inhibitor and beta 2-microglobulin.

Topics: Adult; Albuminuria; Arginine; Aspartic Acid; beta 2-Microglobulin; Bicarbonates; Female; Glycoproteins; Humans; Infusions, Intravenous; Kidney Tubules, Proximal; Male; Proteinuria; Sodium; Sodium Bicarbonate

The human end-stage kidney and its experimental analogue, the remnant kidney in the rat, exhibit widespread tubulo-interstitial disease. We investigated whether the pathogenesis of such tubulo-interstitial injury is dependent upon adaptive changes in tubular function and, in particular, in ammonia production when renal mass is reduced. Dietary acid load was reduced in 1 3/4-nephrectomized rats by dietary supplementation with sodium bicarbonate (NaHCO3), while control rats, paired for serum creatinine after 1 3/4 nephrectomy, were supplemented with equimolar sodium chloride. After 4-6 wk, NaHCO3-supplemented rats demonstrated less impairment of tubular function as measured by urinary excretory rates for total protein and low molecular weight protein and higher transport maximum for para-aminohippurate per unit glomerular filtration rate, less histologic evidence of tubulo-interstitial damage, less deposition of complement components C3 and C5b-9, and a lower renal vein total ammonia concentration. Such differences in tubular function could not be accounted for simply on the basis of systemic alkalinization, and differences in tubular injury could not be ascribed to differences in glomerular function. Because nitrogen nucleophiles such as ammonia react with C3 to form a convertase for the alternative complement pathway, and because increased tissue levels of ammonia are associated with increased tubulo-interstitial injury, we propose that augmented intrarenal levels of ammonia are injurious because of activation of the alternative complement pathway. Chemotactic and cytolytic complement components are thereby generated, leading to tubulo-interstitial inflammation. Thus, alkali supplementation reduces chronic tubulo-interstitial disease in the remnant kidney of the rat, and we propose that this results, at least in part, from reduction in cortical ammonia and its interaction with the alternative complement pathway.

Topics: Acid-Base Equilibrium; Ammonia; Animals; Bicarbonates; Complement C3; Complement Pathway, Alternative; Creatinine; Diet; Fluorescent Antibody Technique; Glomerular Filtration Rate; Hemolysis; Kidney Failure, Chronic; Nephrectomy; Proteinuria; Rats; Sodium; Sodium Bicarbonate

During a total fast in obese subjects, the daily rate of nitrogen excretion undergoes only a small further decline after 2 wk, the excretion rate being about 5 g N/day. At this time, ammonium and urea each constitute about one-half of this excretion. The purpose of this study was to consider two alternative hypotheses: first, that the near plateau in nitrogen excretion represents an irreducible minimum rate of net protein breakdown in order to supply essential organs with calories in the form of glucose; second, that protein breakdown could be further reduced by minimizing the requirement to provide nitrogen for ammonium excretion during the ketoacidosis of fasting. Because ammonium excretion is largely controlled by acid-base balance, 150 mmol of sodium bicarbonate plus 60 mmol of potassium chloride were administered daily to decrease ammonium excretion in eight obese subjects who were totally fasting for more than 14 days. Urine ammonium nitrogen fell with this treatment (from 3.8 +/- 0.4 to 2.0 +/- 0.4 g N/g creatinine). In addition, there was a smaller fall in the rate of urea excretion (from 2.5 +/- 0.2 to 2.1 +/- 0.3 g N/g creatinine) together with a fall in the blood urea nitrogen. Therefore, it appears that ammonium excretion contributes to the negative nitrogen balance of a prolonged total fast, as assessed over a 3-day period of observation, is responsible for about one-third of the net lean body mass loss.

Topics: Acidosis; Adult; Bicarbonates; Blood Urea Nitrogen; Fasting; Female; Humans; Ketone Bodies; Ketosis; Male; Middle Aged; Nitrogen; Obesity; Potassium Chloride; Proteinuria; Sodium Bicarbonate