131I-hippuran Clearances Research Articles

Clinical Correlates and Prognostic Value of Proenkephalin in Acute and Chronic Heart Failure

BackgroundProenkephalin (pro-ENK) has emerged as a novel biomarker associated with both renal function and cardiac function. However, its clinical and prognostic value have not been well evaluated in symptomatic patients with heart failure. Methods and ResultsThe association between pro-ENK and markers of renal function was evaluated in 95 patients with chronic heart failure who underwent renal hemodynamic measurements, including renal blood flow (RBF) and glomerular filtration rate (GFR) with the use of 131I-Hippuran and 125I-iothalamate clearances, respectively. The association between pro-ENK and clinical outcome in acute heart failure was assessed in another 1589 patients. Pro-ENK was strongly correlated with both RBF (P < .001) and GFR (P < .001), but not with renal tubular markers. In the acute heart failure cohort, pro-ENK was a predictor of death through 180 days, heart failure rehospitalization through 60 days, and death or cardiovascular or renal rehospitalization through day 60 in univariable analyses, but its predictive value was lost in a multivariable model when other renal markers were entered in the model. ConclusionsIn patients with chronic and acute heart failure, pro-ENK is strongly associated with glomerular function, but not with tubular damage. Pro-ENK provides limited prognostic information in patients with acute heart failure on top of established renal markers.

Short-term renal hemodynamic effects of tolvaptan in subjects with autosomal dominant polycystic kidney disease at various stages of chronic kidney disease

Vasopressin V2-receptor antagonists may delay disease progression in ADPKD. Trials with V2-receptor antagonists have been performed predominantly in patients with an estimated creatinine clearance of 60 ml/min or more. Here we determined renal hemodynamic effects of the V2-receptor antagonist tolvaptan in 27 patients with ADPKD at various stages of chronic kidney disease: group A: >60, group B: 30-60, and group C: <30 ml/min per 1.73 m(2). Measurements were performed before, after 3 weeks of tolvaptan (up titration to 90/30 mg/day, split dose), and 3 weeks after the last dose of tolvaptan. With tolvaptan, a minor, reversible decrease in GFR ((125)I-iothalamate clearance) was found that reached significance in groups A and B: -7.8 (interquartile range -13.7 to -1.3) and -4.3 (-9.7 to -0.9) ml/min per 1.73 m(2), respectively, but not in group C (GFR decrease -0.7 (-1.1 to 1.5) ml/min/1.73 m(2)). The percentage change in GFR, ERPF ((131)I-hippuran clearance), and filtration fraction with tolvaptan did not differ between the three study groups. No differences between the three study groups were found in other main efficacy variables, besides smaller increases in urine volume in group C during tolvaptan treatment. Tolvaptan was well tolerated, with only two patients withdrawing. Thus, doses of tolvaptan typically used in patients with ADPKD do not produce a difference in renal hemodynamic profile in chronic kidney disease stages 1 through 4, but minor GFR drops may be observed in individual patients.

Anaemia in chronic heart failure is not only related to impaired renal perfusion and blunted erythropoietin production, but to fluid retention as well

Anaemia is prevalent in the chronic heart failure (CHF) population, but its cause is often unknown. The present study aims to investigate the relation between anaemia, renal perfusion, erythropoietin production, and fluid retention in CHF patients. We studied 97 patients with CHF, of which 15 had anaemia (Hb<13.0 g/dL in men and Hb<12.0 g/dL in women), without haematinic deficiencies. Glomerular filtration rate (GFR) and extracellular volume (ECV) were measured as the clearance and the distribution volume of constantly infused 125I-iothalamate, respectively. Effective renal plasma flow (ERPF) was determined as the clearance of 131I-hippuran. Anaemic CHF patients displayed significantly reduced GFR (P=0.002), ERPF (P=0.005) and EPO production (P=0.001), and an elevated ECV (P=0.015). Multivariable analysis demonstrated that lower GFR (P=0.003), lower ERPF (P=0.004), lower EPO production (P=0.006), and a higher ECV (P=0.001) were significant independent predictors of lower haemoglobin levels. Anaemia in CHF is not only independently associated with impaired renal perfusion and blunted EPO production, but to fluid retention as well.

A porcine model of systemic and renal haemodynamic responses to infrarenal aortic cross-clamping

Objectives: cross-clamping of the infrarenal aorta is associated with complex haemodynamic disturbances. Several experimental models of aortic cross-clamping (AXC) have been described with heterogeneous results. The main purpose of this study was to establish an animal model in which infrarenal AXC could reproduce similar systemic and renal haemodynamic changes to those observed in humans. Methods: eleven anaesthetised pigs underwent AXC just below the renal arteries. Renal blood flow was measured using clearance of 131I hippuran. Systemic and renal parameters were collected at 3 consecutive 30-min periods. Results: AXC did not alter the extraction fraction of 131I hippuran but was accompanied by significant (13%) decrease in cardiac index (p = 0.005) and a 23% increase in mean arterial pressure (p = 0.005). AXC induced significant 135% increase in renal vascular resistance (p = 0.012) and a 35% decrease in renal blood flow (p = 0.016). This worsened after removal of the aortic clamp, whereas systemic variables returned to baseline levels. Conclusions: this AXC animal model reproduces the changes observed in humans. It provides a reliable animal model which allows to investigate the underlying mechanisms of renal vasoconstriction and the effect of new drugs.Eur J Vasc Endovasc Surg 25, 72–78 (2003)

Renal 131I-hippuran extraction in man: effects of dopamine.

This study examined the 131I-hippuran extraction fraction during baseline renal blood flow rates and at high flow rates induced by dopamine. In 12 healthy subjects, arterial and renal venous sampling was used to measure the renal extraction of 131I-hippuran. Effective renal plasma flow values determined by the urinary clearance of 131I-hippuran were compared with renal plasma flow values corrected for incomplete extraction of 131I-hippuran. Dopamine (3 micro g kg-1 min-1) decreased 131I-hippuran extraction from 75 +/- 4% at baseline to 62 +/- 6% (means +/- 95% confidence intervals, P < 0.001). Hence, the increase in renal plasma flow (85 +/- 23%) greatly exceeded the rise in effective renal plasma flow (51 +/- 15%, P < 0.002). Dopamine induced increases in renal blood flow are largely under-estimated when measurements are not corrected for incomplete extraction of 131I-hippuran.

Functional effects of renal artery stent placement on treated and contralateral kidneys

This study examined the effects of stent placement for renal artery stenosis on the function of treated and contralateral kidneys. Eighteen patients who underwent stent placement for unilateral renal artery stenosis presenting with hypertension and/or renal failure were studied before angiography and stent placement and at their one-year follow-up. Renal vein blood samples were taken at both sides, at each side simultaneously with a sample from the aorta, to measure the plasma renin concentration and the concentrations of 131I-hippuran and 125I-thalamate during constant systemic infusion of these radiochemicals. This allowed an assessment of the single-kidney contributions to the total renin secretion, effective renal plasma flow (131I-hippuran clearance) and glomerular filtration rate (125I-thalamate clearance). At the one-year follow-up, the vein-to-artery renin ratio at the treated side had decreased to normal, from 1.65 +/- 0.131 to 1.23 +/- 0.076 (mean +/- SEM; P = 0.011), indicating an improved renal blood flow. Contralaterally it rose from 1.09 +/- 0.042 to 1.17 +/- 0.029 (P = 0.055) at follow-up. The extraction ratio of 131I-hippuran improved at the treated side (0.48 +/- 0.049 to 0.62 +/- 0.034; P = 0.003) and contralaterally (0.67 +/- 0.033 to 0.73 +/- 0.026; P = 0.043). The extraction ratio of 125I-thalamate, which equals filtration fraction, improved at both sides (0.12 +/- 0.014 to 0.17 +/- 0.012 at the treated side, P = 0.001; 0.18 +/- 0.013 to 0.22 +/- 0.011 contralaterally, P = 0.002). Two-kidney effective renal blood flow and glomerular filtration rate remained unchanged. Renal artery stenting was capable of causing improvement of glomerular filtration rate of the treated kidney, although the overall glomerular filtration rate did not change.

DIETARY SODIUM INDUCED INCREASE IN RENAL FUNCTION IS ASSOCIATED WITH AN INCREASE IN NITRITE LEVELS

348 Nitric oxide (NO) may play an important role in the regulation of renal function and in the development of sodium-sensitive hypertension. We hypothesized that the increased renal function due to dietary sodium(Na+) loading would be associated with an increase in plasma and urine NO2- levels, in vivo markers of endogenous NO production. To test this hypothesis, seventeen older (63±8 yrs), nondiabetic, moderately obese (34±9% body fat) hypertensives were studied. Subjects were studied at the end of 1-wk of low (20 mEq /d) and high (200 mEq /d) Na+ diets that were identical in composition except for their Na+ content. Renal plasma flow (RPF) and glomerular filtration rate(GFR) were determined by plasma and urinary clearance of 131I-hippuran and 99mTc-DTPA respectively. RPF, GFR, and intra-arterial blood pressure were obtained at the end of each diet. Plasma and urine samples were obtained after a 12-hr fast and NO2- levels were determined using the Griess assay. Plasma NO2- levels increased on the high Na+ diet (25.7±2.5 to 31.8±2.4 μM, P=.06) compared to the low Na+ diet. Although there were no significant changes in GFR or RPF, there was a positive relationship (r=.53, P=.02) between the change in plasma NO2- levels and change in GFR, and the change in plasma NO2- levels and the change in glomerular filtration fraction(GFR/RPF; r=.37, P=.12). The change in RPF was not related to either the change in plasma or urinary NO2- levels. These results suggest that endogenous NO production plays a role in the improvement in GFR induced by dietary Na+ loading. We conclude that impaired NO production may be involved in the inappropriate decline in renal function during dietary Na+ loading. FigureFigure

Can Continuous Intraperitoneal Infusion of 125I-Iothalamate and 131I-Hippuran Be Used for Measurement of GFR in Conscious Rats?

We previously described a method to measure GFR in conscious spontaneously voiding rats. This method circumvents the need for anesthesia and for bladder instrumentation. It's main principle is the correction of renal 125I-iothalamate clearance for incomplete urine collection by the ratio of plasma and renal clearance of co-infused 131I Hippuran. A disadvantage of this technique is the requirement of an intra-arterial catheter for infusion of the renal function tracers. We therefore tested whether intraperitoneal infusion of 125I-Iothalamate and 131I-Hippuran can be used for such a GFR measurement in conscious spontaneously voiding rats.We found that during intraperitoneal administration, stable plasma levels of 131I-Hippuran could be obtained. However, urinary recovery of 131I-Hippuran was incomplete (66 ± 32%), leading to a significant overestimation of GFR by 140 ± 113% in comparison with the GFR measured by the intra-arterial technique. Thus intraperitoneal infusion of renal function tracers cannot replace intra-arterial infusion.

Estimation of 99Tcm-MAG3 clearance using a single blood sample obtained over a continuous time interval.

Simplified methods based on a single blood sample have been proposed to estimate the clearance of 131I-hippuran (HIP) and 99Tcm-mercaptoacetyltriglycine (MAG). The blood sample is usually drawn at that time which yields a minimum error between the estimated clearance and that obtained by the standard nine-sample method. In this paper, we establish the regression equations to obtain the HIP and MAG clearances using one sample withdrawn during a fixed time interval. As HIP has long been the agent of choice, we have also established regression equations to estimate the clearance of HIP using one sample after MAG administration. Our results suggest that it is possible to obtain plasma samples 30-50 min post-injection which result in an error of the estimate only slightly higher than the minimum.

Precision of glomerular filtration rate determinations for long-term slope calculations is improved by simultaneous infusion of 125I-iothalamate and 131I-hippuran.

In studies on the progression of chronic renal failure the measurement of GFR must be very reliable. Sequential determination of GFR using the renal clearances of exogenous tracers such as inulin or iothalamate is the most accepted method. However, because of inaccuracies in urine collection, intratest variation, and thus intertest variation, of these clearances is considerable. This has a negative impact on the precision of long-term slope estimations. A previously described method of GFR determination on the basis of simultaneous infusion of 131I-hippuran and 125I-iothalamate corrects for inaccurate urine collection. To study whether this correction method improves the precision of the GFR slope measurement, this study analyzed longitudinal GFR data obtained in 71 patients with renal disease during a follow-up of 84 to 180 wk (477 renal function studies). All GFR were calculated by using both the standard renal clearance method and the correction method. The intratest and intertest coefficient of variation was significantly smaller for the correction method compared with the standard method (1.93 +/- 0.20 versus 8.48 +/- 1.66% P < 0.0005; and 2.88 +/- 0.32 versus 5.12 +/- 0.66%, P < 0.005, respectively). As a result, the precision of the GFR slope estimation was significantly better with the correction method compared with the standard method (error of the slope, 1.63 +/- 1.09 versus 2.35 +/- 2.36 mL/min per yr, P < 0.01). This improvement in precision of the slope by using the correction method reduces the necessary sample size needed to detect a GFR slope difference between interventions to about 30% of that needed when using the standard method. It is concluded that the precision of GFR measurements is improved by using correction for inaccurate urine collection with concomitant 131I-hippuran clearance.

Iodine-131 Hippuran for the estimation of renal plasma flow: requirements for radiochemical purity.

For many years iodide-131 Hippuran has been used as a tracer to measure effective renal plasma flow (ERPF). Because of the low renal clearance of free 131I-iodide and the inability to count it separately from 131I-Hippuran, free 131I-iodide will lower the calculated 131I-Hippuran clearance, resulting in a lower estimated ER-PF. This study was performed to establish the maximum allowable radiochemical impurity of free 131I-iodide in 131I-Hippuran preparations for ERPF measurements in continuous clearance studies. A known amount of 123I-iodide was added to the (131I-iodide-free) 131I-Hippuran solution used for continuous infusion clearance studies in nine patients. 123I-iodide activity was used because it can be counted separately from 131I-Hippuran in the infusion solutions and plasma samples while it behaves exactly like 131I-iodide, so that the results obtained with 123I-iodide can be extrapolated to 131I-iodide. After performing the clearance studies, the ERPF was calculated firstly with 131I-Hippuran activity only (= true ERPF) and secondly including the free radioactive iodide activity (= false ERPF) in the clearance formula. As expected, if free 131I-iodide is present in the infusion solution, its concentration in plasma will be highest at the end of the clearance study. The 131I-iodide concentration in plasma relative to the 131I-Hippuran concentration will be higher in patients with high ERPF values.(ABSTRACT TRUNCATED AT 250 WORDS)

9. Simultaneous measurement of 131I-hippuran and 99Tcm-MAG3 clearances using a two-sample, two-compartment method

1 Nuclear Medicine, City Hospital Triemli, Zürich and 2Department of Nuclear Medicine, Inselspital, University of Berne, Berne, Switzerland

Natriuretic and Vasoactive Hormones and Glomerular Hyperfiltration in Hyperglycaemic Type 2 Diabetic Patients: Effect of Insulin Treatment

Evidence that an increase in plasma atrial natriuretic peptide (ANP) concentrations mediates, at least in part, glomerular hyperfiltration in diabetic rats prompted us to study the relationship between ANP and renal haemodynamics in hyperfiltering type 2 diabetic patients in association with other hormones implicated in the control of glomerular filtration rate (GFR) (catecholamines, vasopressin, renin) and in sodium tubular transport (aldosterone, ouabain-displacing factor, ODF). Since hyperglycaemia is also associated to hyperfiltration, diabetic patients who presented with secondary drug failure were studied both in hyperglycaemic and in normoglycaemic condition. For this purpose, 11 normotensive non-macroproteinuric hyperfiltering patients with type 2 diabetes were treated with an 8-day continuous insulin infusion (days 0-7). Dehydration was prevented or corrected and natriuresis was on day 0 above 100 mmol/day. The following parameters were determined on days 0 and 7: GFR and renal plasma flow (RPF) by 99mTc-DTPA and 131I-hippuran clearances; the extracellular volume, assimilated to the DTPA diffusion volume; urinary ODF by receptor-binding assay and urinary as well as plasma catecholamines by HPLC after extraction on alumin. Plasma ANP and antidiuretic hormone (ADH) were measured by radioimmunoassay after extraction on phenyl-silylsilica (ANP) and with ether (ADH). Unextracted plasma was used for radioimmunological measurement of plasma renin activity and aldosterone. When correcting hyperglycaemia to normoglycaemia GFR decreased from high to normal mean value (138 +/- 27 and 115 +/- 6 ml/min, p < 0.001), RPF followed the same trend, and the DTPA diffusion volume did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of halothane and isoflurane on transient renal dysfunction associated with infrarenal aortic cross-clamping

Aortic cross-clamping for reconstructive aortic surgery is associated with impairment of renal function. Halothane or isoflurane was used to assess the influence of volatile anesthesia on renal hemodynamics during aortic surgery. Nineteen patients with normal preoperative creatinine clearances who were scheduled for reconstructive aortic surgery were randomly divided into two groups: halothane group (n = 9) and isoflurane group (n = 10). Induction of anesthesia consisted of midazolam, fentanyl, and pancuronium. Anesthesia was maintained with fentanyl and halothane or isoflurane in nitrous oxide and oxygen (50/50). Systemic hemodynamics were similar in both groups throughout surgery. Before aortic cross-clamping, effective renal plasma flow (ERPF) ( 131I-hippuran clearance) and glomerular filtration rate (GFR) ( 99Tc-DTPA clearance) were significantly lower in the halothane group (118.4 ± 25.6 and 19.7 ± 5.2 mL/min, respectively) than in the isoflurane group (253.4 ± 51.5 and 44.9 ± 8.4 mL/min) (P < 0.05 for both). During cross-clamping, the renal variables were not markedly affected in either group and remained higher in the isoflurane-anesthetized patients (232.9 ± 47.1 and 49.5 ± 1.2 mL/min for ERPF and GFR, respectively) than in the halothane-anesthetized patients (132.4 ± 31.6 and 14.8 ± 3.7 mL/min, respectively) ( P < 0.05). After aortic unclamping, ERPF increased markedly in both groups (467.8 ± 122 and 362.5 ± 57.7 mL/min in the halothane and isoflurane groups, respectively), as did GFR (74.8 ± 22 and 71.8 ± 13.1 mL/min, respectively). These results suggest that anesthesia with halothane is associated with transient renal vasoconstriction during abdominal surgery. In contrast, aortic cross-clamping during isoflurane anesthesia was not associated with renal hemodynamic impairment.

Effects of ACE inhibition supplementary to beta blockers and diuretics in early diabetic nephropathy

Angiotensin converting enzyme (ACE) inhibition has shown promising results in diabetic nephropathy, but long-term results on survival are not available. In a cohort of patients receiving antihypertensive treatment predominantly consisting of beta blockers in combination with diuretics, support for an improved survival has been presented. Addition of ACE inhibition to such a combination treatment may be favorable both due to the suggested renoprotective effects of ACE inhibitors and because diuretics activate the renin-angiotensin system. In 10 insulin-dependent diabetic patients with early diabetic nephropathy [urinary albumin excretion rate (UAE) less than 100o micrograms/min], who were receiving continuous therapy with metoprolol and bendroflumethiazide, a double-blind crossover study with four months addition of ramipril 5 mg (Ramace) and placebo was conducted. UAE (radioimmunoassay) and fractional albumin excretion were significantly reduced after the four months of ramipril administration [UAE: 114.1 x/divided by 1.3 (geometric mean x/divided by confidence factor] versus 174.6 x/divided by 1.2 micrograms/min, 2P less than 0.005). Renal plasma flow (clearance of 131I-hippuran) tended to increase [497 +/- 25 (mean +/- SE) vs. 464 +/- 28 ml/min/1.73 m2, 2P = 0.08], while GFR (125I-iothalamate) stayed unchanged (121 +/- 8 vs. 120 +/- 9 ml/min/1.73 m2). Mean arterial pressure during clearance studies fell moderately (95 +/- 3 vs. 101 +/- 1 mm Hg, 2P less than 0.05) and renal resistance was decreased (2P less than 0.03). ACE activity was suppressed in all patients. Twenty-four-hour ambulatory blood pressure measurements were not significantly different after the two periods (daytime averages: 91 +/- 2 vs. 93 +/- 2, nighttime 80 +/- 2 vs. 84 +/- 3 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of short-term treatment with naproxen on kidney function in insulin-dependent diabetic patients with microalbuminuria

The renal effects of the prostaglandin synthesis inhibitor naproxen was investigated in eight patients with incipient type I diabetes nephropathy. The patients were treated with 1000 mg naproxen daily for 4 days in a placebo-controlled double-blind cross-over study. Naproxen reduced urinary prostaglandin E2 (PGE2) excretion by 60%, from 276 ng/24 h to 110 ng/24 h (P<0.05). Plasma renin activity (PRA) was reduced by 45% (F<0.05). Glomerular filtration (GFR) (single bolus 99mTc-DTPA technique) and effective renal plasma flow (ERPF) (131I-Hippuran clearance) were unchanged by naproxen. Microalbuminuria and renal albumin clearance was unchanged as was also urinary excretion of sodium, glandular kallikrein and β2-microglobulin (β2-M). Our results show that albumin excretion in incipient diabetic nephropathy is not solely dependent on the renal prostaglandin system. The difference in action between naproxen in this study and indomethacin in previous reports, could be caused by renal actions of indomethacin independent of the prostaglandin system.

Glomerular filtration rate, 131I-hippuran clearance and estimated creatinine clearance in cancer patients

Glomerular filtration rate (GFR), 131I-Hippuran clearance and estimated creatinine clearance were investigated in 34 patients with cancer. For Hippuran clearance and GFR, analysed with the X-ray contrast (iohexol) and fluorescence technique, the least square linear regression coefficient was 5.01 +/- 0.41 (r = 0.91). This value concurs with the five to one ratio between GFR and renal plasma flow known from normal physiology and supports that Hippuran clearance is a valid measure of renal function. When the individual values of Hippuran clearance were divided by 5.01, the mean difference between the methods was 0.4 ml min-1 1.73 m-2 with standard deviation 13.4 ml min-1 1.73 m-2. The lower and upper limits of agreement were -26.7 and 25.9 ml min-1 1.73 m-2, respectively. Comparing creatinine clearance estimated from the serum creatinine level with GFR, the limits of agreement were -29.4 and 21.6 ml min-1 1.73 m-2. These agreement limits are in the same range as those which can be calculated from the data from other studies.

Effects of short-term treatment with naproxen on kidney function in insulin-dependent diabetic patients with microalbuminuria

The renal effects of the prostaglandin synthesis inhibitor naproxen was investigated in eight patients with incipient type I diabetes nephropathy. The patients were treated with 1000 mg naproxen daily for 4 days in a placebo-controlled double-blind cross-over study. Naproxen reduced urinary prostaglandin E2 (PGE2) excretion by 60%, from 276 ng/24 h to 110 ng/24 h (P less than 0.05). Plasma renin activity (PRA) was reduced by 45% (P less than 0.05). Glomerular filtration (GFR) (single bolus 99mTc-DTPA technique) and effective renal plasma flow (ERPF) (131I-Hippuran clearance) were unchanged by naproxen. Microalbuminuria and renal albumin clearance was unchanged as was also urinary excretion of sodium, glandular kallikrein and beta 2-microglobulin (beta 2-M). Our results show that albumin excretion in incipient diabetic nephropathy is not solely dependent on the renal prostaglandin system. The difference in action between naproxen in this study and indomethacin in previous reports, could be caused by renal actions of indomethacin independent of the prostaglandin system.

Renal function related to different treatment modalities for malignant germ cell tumours

The renal function was evaluated with 131I-Hippuran clearance in 171 patients with malignant germ cell tumours. Assessments were performed before treatment and at three fixed times afterwards within 5 years. The patients were treated with surgery only (20 patients), infra-diaphragmatic radiotherapy only (median midplane dose 36 Gy) (48 patients), cisplatin-based chemotherapy (total cisplatin dose 500-850 mg) plus surgery (64 patients), cisplatin-based chemotherapy (total cisplatin dose greater than 850 mg) with or without surgery (23 patients) or cisplatin-based chemotherapy (total cisplatin dose 500-850 mg) plus infra-diaphragmatic radiotherapy (16 patients). No renal impairment was observed for patients treated with surgery only. In patients who received radiotherapy no change of the renal function occurred during the first year post-treatment. Three to five years after treatment discontinuation a statistically significant reduction within the normal range was observed in patients who were greater than 40 years at the time of irradiation. Cisplatin-based chemotherapy led to a statistically significant irreversible renal impairment for all the three groups. The greatest reduction was seen in patients who received the highest total cisplatin dose or who were treated with irradiation in addition to chemotherapy. The clinical significance of the observed nephrotoxicity is still unknown.

Dietary supplementation with fish oil modifies renal reserve filtration capacity in postoperative, cyclosporin A-treated renal transplant recipients

The effect of a daily supplementation of 6 g fish oil (30% C20:5 omega-3 = EPA and 20% C22:6 omega-3 = DHA) for 1 month on renal function variables was investigated in a placebo-controlled (6 g coconut oil), prospective, randomized, double-blind study in acute postoperative cyclosporin A (CyA)-treated renal transplant recipients. Seventeen patients ingested placebo capsules (EPA-) and 14 patients fish oil (EPA+). Renal function tests were performed using the simultaneous determination of 125I-iothalamate and 131I-hippuran clearances for glomerular filtration rate (GFR) and effective renal plasma flow (ERPF), respectively. Renal reserve filtration capacity was assessed by dopamine infusion, amino acid infusion, and a combination of both stimuli. After 1 month there were no significant differences in rejection episodes, CyA dose, or CyA levels. In contrast to our earlier observations, serum creatinine, creatinine clearance, GFR, and ERPF did not differ between the EPA- and EPA+ groups. Filtration fraction (FF) differed significantly, being 0.21 in the EPA- group versus 0.26 in the EPA+ group. To exclude the possible influence of a rejection episode, the nonrejecting patients were analyzed separately, creating the subgroups EPA + re - and EPA - re -. These two groups were comparable in age, donor age, and GFR. The EPA + re-group had a significantly lower ERPF (164 ml/min per 1.73 m2) than the EPA-re- group (262 ml/min per 1.73 m2). FF was significantly higher in the EPA+ re-group (0.26) than in the EPA-re-group (0.21).(ABSTRACT TRUNCATED AT 250 WORDS)