The increase in albuminuria induced by exercise is not associated with preferential excretion of glycated albumin in Type 1 (insulin-dependent) diabetic patients

Summary The increase in urinary albumin excretion induced by acute exercise in Type 1 (insulin-dependent) diabetic patients is associated with the urinary excretion of cationic proteins. To test whether the renal excretion of glycated albumin (more anionic than non-glycated albumin) is affected by exercise, we submitted seven normoalbuminuric (albumin excretion rate < 30 mg/24 h) Type 1 diabetic patients and six well-matched healthy subjects to an exercise test (600 kpm/min for 20 min) on a bicycle ergometer, preceded and followed by a 1-h resting period. The selectivity index (renal clearance of non-glycated/glycated albumin) was not significantly different among the pre-exercise, exercise and post-exercise periods, either in the normal subjects (1.01±0.03 vs 1.08±0.06 vs 1.08±0.05) or in the diabetic patients (1.25±0.09 vs 1.20±0.07 vs 1.20+-0.06), whereas it was significantly higher (p < 0.05) in diabetic patients compared to healthy subjects during pre-exercise. These results are not consistent with the hypothesis that acute exercise may induce a preferential excretion of glycated albumin.     

The relationship between obesity and transforming growth factor beta on renal damage in essential hypertension

The aim of this study was to evaluate the effect of obesity on renal functions and the possible relationship between TGF-beta1 and obesity in hypertensive patients. Seventy newly diagnosed, hypertensive patients (male/female 36/34, aged 45.0 +/- 8.0 years) and 30 (male/female 17/13, aged 41.8 +/- 7.7 years) normotensive controls were included. Patients in both groups were analyzed for serum levels of glucose, creatinine, uric acid, lipids, and TGF-beta1. A 24-hour urine sample was also obtained; creatinine clearance rate and urinary albumin excretion (UEA) were investigated. TGF-beta1 levels were significantly higher (40.7 +/- 13.6 versus 34.2 +/- 12.1 pg/mL, P = 0.02), and creatinine clearance was significantly lower in patients compared with controls (98.9 +/- 25.5 versus 124.5 +/- 23.1 mL/min. per. 1.73 m(2), P = 0.001). Serum TGF-beta1 levels (45.2 +/- 14 versis 38.0 +/- 12.8 pg/mL, P = 0.03), creatinine clearance rates (109.8 29.9 versus 93.0 +/- 20.8 mL/min. per. 1.73 m(2), P = 0.001), and urinary albumin excretion (55.7 +/- 62.0 versus 12.7 +/- 12.6 mg/24 h, P = 0.002) were higher in obese hypertensive patients than in nonobese patients. In hypertensive patients, TGF-beta1 levels correlated with body mass index (r = 0.296, P = 0.01) and creatinine clearance (r = 0.238, P = 0.04). The results suggest that increased body mass index is associated with increased creatinine clearance, urinary albumin excretion, and TGF-beta1 levels in essential hypertension. In addition, TGF-beta1 is positively correlated with body mass index and creatinine clearance in patients with essential hypertension.     

Transcapillary escape rate of albumin in hypertensive patients with Type 1 (insulin-dependent) diabetes mellitus

Summary Diabetic patients with elevated urinary albumin excretion rate (incipient or clinical nephropathy) also have an increased transcapillary escape rate of albumin. This study was designed to clarify whether this is caused by a general vascular dysfunction or by elevated systemic blood pressure. The systemic blood pressure and the transcapillary escape rate of albumin were measured in the following groups after 4 weeks without antihypertensive treatment: Group 1 — eleven healthy control subjects. Group 2 — ten Type 1 (insulin-dependent) diabetic patients with incipient nephropathy (urinary albumin excretion rate: 30–300 mg/24 h) and normal blood pressure. Group 3 — eleven non-diabetic patients with essential hypertension. Group 4 — nine Type 1 diabetic patients with hypertension but normal urinary albumin excretion (<30 mg/24 h). Group 5 — eleven Type 1 diabetic patients with nephropathy (urinary albumin excretion rate > 300 mg/24 h) and hypertension. Systolic and diastolic blood pressure were similar in the three hypertensive groups: group 3, 148±8/95±6; group 4, 150±12/94±8 and group 5; 152±12/92±7mmHg, but significantly elevated (p<0.001) compared to control group 1,117±12/74±9 and group 2, 128±7/82±4 mm Hg. The transcapillary escape rate of albumin was similar in the control subjects (5.2±2.7%) and the subjects in the normoalbuminuric groups 3 and 4 (6.2±1.9 and 5.1±1.4 %, respectively) and significantly lower (p<0.001) than in patients with elevated urinary albumin excretion without or with hypertension group 2, 10.1±2.8 and group 5, 11.4±5.7 %. The increased transcapillary escape rate of albumin in patients with elevated urinary albumin excretion is unrelated to moderate systemic hypertension and may therefore be caused by alterations in the properties of the capillary walls.     

Renal abnormalities in a population of patients with psoriatic arthritis.

OBJECTIVE: To investigate the prevalence of and to identify predictive factors for renal abnormalities in patients with psoriatic arthritis (PsA). METHODS: 73 patients with PsA were consecutively examined by laboratory analyses and clinically for joint manifestations. Renal function was estimated by creatinine clearance and urinary albumin. RESULTS: 17 (23.3%) of the patients had renal abnormalities as defined by creatinine clearance below the lower cut off of normal distribution (mean - 2 SD) and/or urinary excretion of albumin more than 25 mg/24 h. These patients were significantly older at the time of the study, older at joint disease onset, had longer skin disease duration, increased serum levels of beta2-microglobulin, and higher incidence of increased ESR and/or CRP levels. Increased ESR/CRP levels had significantly predictive value in multivariate analysis. CONCLUSIONS: In this study subclinical renal abnormalities was a prevalent finding. Predictive factor was inflammatory activity measured by laboratory variables. There were no predisposing effects of NSAID or DMARD therapy.     

Ambulatory arterial stiffness index and renal abnormalities in primary hypertension

OBJECTIVE: Arterial stiffness is a predictor of cardiovascular mortality in the general population as well as in hypertension and end-stage renal disease. We investigated the relationship between a recently proposed ambulatory blood pressure monitoring-derived index of arterial stiffness and early signs of renal damage in patients with primary hypertension. DESIGN AND SETTING: A total of 168 untreated patients with sustained primary hypertension were studied. Ambulatory arterial stiffness index (AASI) was calculated based on 24-h ambulatory blood pressure readings. Albuminuria was measured as the albumin to creatinine ratio. Creatinine clearance was estimated using the Cockcroft-Gault formula, and the interlobar resistive index was evaluated by renal ultrasound and Doppler examination. RESULTS: AASI was positively related to urinary albumin excretion and resistive index, and was negatively related to estimated creatinine clearance and renal volume to the resistive index ratio. Patients with AASI above the median (i.e. > 0.51) showed a higher prevalence of microalbuminuria and a mild reduction in creatinine clearance. Moreover, patients with microalbuminuria or a mild reduction in creatinine clearance had significantly higher AASI values compared with those without, and the greater the renal involvement, the greater the AASI. After adjusting for several potentially confounding variables, we found that each standard deviation increase in AASI (i.e. 0.16) entails an almost twofold greater risk of renal involvement. CONCLUSION: Increased AASI is independently associated with early signs of renal damage in patients with sustained primary hypertension. These results strengthen the usefulness of AASI and ambulatory blood pressure monitoring in cardiovascular risk assessment.     

Orosomucoid in urine predicts cardiovascular and over-all mortality in patients with Type II diabetes

Aims/hypothesis: Urinary orosomucoid excretion rate is increased in a substantial proportion of patients with Type II (non-insulin-dependent) diabetes mellitus and normal urinary albumin excretion rate. The aim of this study was to determine whether increased urinary orosomucoid excretion rate is predictive of increased mortality in patients with Type II diabetes. Methods: In a cohort study including 430 patients with Type II diabetes, baseline urinary samples were analysed for orosomucoid and albumin. Mean follow-up was 2.4 years. Results: We found that 188 (44 %) patients had normal and 242 (56 %) patients had increased urinary orosomucoid excretion rates. During the study period 41 patients died; out of these 23 patients died of cardiovascular diseases. Odds ratio for all-cause mortality was 2.50 (95 % CI 1.00–6.22) and odds ratio for cardiovascular mortality was 9.81 (1.31–73.6) having increased urinary orosomucoid excretion rate at baseline (odds ratios adjusted for age, sex, duration of diabetes, cardiovascular diseases, weight, medication, HbA_{1 c}, plasma creatinine and urinary albumin excretion rate). Urinary albumin excretion rate was an independent predictor of all-cause mortality when urinary orosomucoid excretion rate was not included in the analysis. Subgroup analysis revealed that 39 % of the patients with normal urinary albumin excretion rate (n = 251) had increased urinary orosomucoid excretion rates and that these patients had a higher cardiovascular mortality (p = 0.007) than patients with normal urinary albumin excretion rate and normal urinary orosomucoid excretion rates. Conclusion/interpretation: We found that urinary orosomucoid excretion rate predicted all-cause and cardiovascular mortality in patients with Type II diabetes independently from other risk factors. [Diabetologia (2002) 45: 115–120] Received: 24 July 2001 and in revised form: 17 September 2001     

Correlation between urinary activity of N-acetyl-β-d-glucosaminidase (NAG) and albumin excretion rate in type II (non-insulin-dependent) diabetic subjects

Summary Different kidney diseases are often associated with high urinary excretion of N-acetyl-β-D-glucosaminidase (NAG), a lysosomal enzyme involved in the breakdown of glycoproteins, whose activity is also increased in diabetic patients with poor metabolic control or vascular complications. In order to evaluate the relationship between renal function and urinary NAG levels in diabetes mellitus, 30 type II diabetic patients without evidence of kidney disease and 18 control subjects were studied. In each subject 24-h urinary excretion rates of NAG (fluorimetric method), albumin and β₂-microglobulin (radioimmunoassay), together with⁵¹Cr-EDTA clearance were performed. In diabetic patients urinary levels of NAG (356±25vs 162±9.2 nmol/h/mg creatinine, p<0.0001) and albumin (21±2.5vs 4.3±0.5 mg/24h, p<0.0001) were significantly higher than in the controls, while β₂-microglobulin levels and⁵¹Cr-EDTA clearance did not differ in the two groups. Moreover in diabetic patients NAG and albumin levels were positively and significantly correlated (r=0.63, p<0.001). These results suggest that urinary NAG excretion rate may be altered early in diabetic patients with apparently normal renal function; its diagnostic value seems to be similar to that of the albumin excretion rate.     

Intermittent diabetic microalbuminuria: Association with blood pressure,glycemic control,and protein intake

The factors associated with intermittent microalbuminuria were studied over 7 years in 49 Type I and 53 Type II diabetics who had normal initial albumin clearance. Fasting plasma glucose, HbA₁, 24 hour urinary glucose, blood pressure, protein intake (24 hour urinary urea), and the renal clearance of albumin, transferrin, and IgG, as well as total proteinuria, were assessed every 3–6 months. Fifteen Type I and 11 Type II diabetics had 40 and 31 episodes, respectively, of intermittent microalbuminuria, defined as an albumin clearance >11 nl/sec, without progressing to persistent microalbuminuria. Rises in transferrin and IgG clearance paralleled albumin clearance in both Type I and Type II diabetics. There were no significant changes in blood pressure or glycemic control during episodes of intermittent microalbuminuria. However, in Type I diabetics, intermittent microalbuminuria was associated with higher levels of urinary urea excretion. This study raises the possibility that increased protein intake may participate in the development of nephropathy in Type I diabetes.     

Effect of a low protein diet on the relationship of nonenzymatic glycation to altered renal structure and function in diabetes mellitus

Renal functional parameters including creatinine clearance, urinary albumin excretion, basement membrane thickening, and levels of nonenzymatic glycation of glomerular basement membrane were studied in streptozotocin-induced diabetic rats and age-matched controls subjected to low protein diet. In addition, these parameters were also assessed in diabetic and streptozotocin injected nondiabetic animals fed a 24% protein diet, which served as “positive controls.” While diabetic animals from both diet groups had similar elevated glycated hemoglobin levels and increased levels of nonenzymatic glycation of glomerular basement membrane, these were significantly elevated as compared to insulin treated diabetic (euglycemic), age-matched controls on an 8% protein diet, and streptozotocin injected nondiabetic animals from both diet groups. However, urinary albumin excretion and creatinine clearance levels were significantly elevated only in the 24% protein diet fed diabetics over values seen in the various groups of animals on 8% and controls on 24% protein diet. In contrast, there were no statistical differences among diabetic, euglycemic and control (8% and 24% protein) animals with respect to creatinine clearance, urinary albumin excretion, and glomerular basement membrane thickness. Taken together these data cast some doubt on the role of nonenzymatic glycation in the development of diabetic nephropathy. Moreover, hyperglycemia per se causes a compensatory increase in kidney size irrespective of protein intake; a low protein diet, however, inhibits the hyperfiltration commonly seen in early diabetic nephropathy. The authors, thus, hypothesize that a low protein diet, by preventing compensatory increase in blood flow to surviving nephrons, in some fashion protects these functional units from subsequent damage and possibly delays the onset of renal failure.     

Evidence of changes in renal charge selectivity in patients with Type 1 (insulin-dependent) diabetes mellitus

Summary Altered filtration of macromolecules due to decreased electrical charge of the glomerular basement membrane might be the initial step in the development of albuminuria in patients with Type 1 (insulin-dependent) diabetes mellitus. We therefore investigated the selectivity index, i. e. renal clearance of non-glycated plasma albumin/clearance of glycated plasma albumin in 38 patients with Type 1 diabetes mellitus. The two albumin molecules differed slightly in charge, non-enzymatic glycated albumin being more anionic at physiological pH compared with unmodified plasma albumin. Glycated albumin in plasma and urine was determined by a specific, sensitive and highly reproducible chromatographic procedure. In diabetic patients with normal urinary albumin excretion, the selectivity index was increased threefold compared with that of non-diabetic subjects (2p< 0.01). A significant correlation (r=0.53, 2p < 0.01) between haemoglobin A_1c and selectivity index was demonstrated in these patients, indicating a change in charge-dependent renal filtration could possibly be attributed to non-enzymatic glycation of components in the glomerular basement membrane and tubuli. Diabetic patients with increased albumin excretion rate had a significantly lower selectivity index compared with patients with normal albumin excretion (2p < 0.01). A significant negative correlation (r=0.85, 2p <0.001, exponential curve fit) was seen between urinary albumin excretion and selectivity index in the diabetic patients, indicating that the capability of differentiating between macromolecules of different charges is again lost with increasing urinary albumin excretion.In conclusion, the selectivity index is significantly increased in Type 1 diabetic patients with normal urinary albumin excretion, possibly due to non-enzymatic glycation of structural glomerular proteins. The selectivity index is again reduced with increasing urinary albumin excretion, possibly due to structural changes different from non-enzymatic glycation. This observation is in accordance with the hypothesis that loss of anionic charges due to reduced heparan sulphate content in glomerular basement membranes plays an important role in the early stages of diabetic renal disease.     

Decreased insulin requirement in relation to GFR in nephropathic Type 1 and insulin-treated Type 2 diabetic patients.

AIMS: In the presence of impaired renal function, patients require less insulin mainly because insulin clearance is prolonged. The aim of this study was to evaluate the insulin requirement related to glomerular filtration rate (GFR) in nephropathic Type 1 and Type 2 diabetic patients. METHODS: In a retrospective study we compared insulin requirement in 20 nephropathic Type 1 diabetic patients and 20 insulin-treated Type 2 diabetic patients from the onset of overt nephropathy until the final stage of renal disease. All patients had proteinuria > 0.5 g/24 h and creatinine clearance >/= 80 ml/min per 1.73 m2 at baseline. Creatinine clearance, urinary protein excretion, glycated haemoglobin and the required insulin doses were determined 3- to 6-monthly, basal C-peptide was measured at the beginning and the end of the observation period. The required insulin doses were evaluated at creatinine clearance rates of 80, 60, 40, 20 and 10 ml/min per 1.73 m2 (or at the initiation of dialysis treatment). RESULTS: The insulin requirement of patients with Type 1 diabetes was reduced from 0.72 +/- 0.16 IU/kg per day at a creatinine clearance rate of 80 ml/min, to 0.45 +/- 0.13 IU/kg per day at a creatinine clearance rate of 10 ml/min (decrement of 38%, P < 0.001). The insulin dose required by Type 2 diabetic patients was reduced from 0.68 +/- 0.28 IU/kg per day at a creatinine clearance rate of 80 ml/min to 0.33 +/- 0.19 IU/kg per day at a clearance rate of 10 ml/min (decrement 51%, P < 0.001). The fall in GFR, urinary protein excretion and glycated haemoglobin levels was similar in the two groups. In patients with Type 2 diabetes, C-peptide levels at the beginning and the end of renal function impairment were 2.2 (0.4-7.3) vs. 2.7 (0.1-4.9) ng/ml (NS). The reduction in insulin requirement was approximately the same in patients with an initial C-peptide level < 1.0 and in those >/= 1.0 ng/ml (decrement 57% vs. 46%). CONCLUSIONS: The reduction in insulin requirement in renal insufficiency is similar in Type 1 and insulin-treated Type 2 diabetic patients. In subjects with Type 2 diabetes, the residual insulin secretion has no impact on the reduction in insulin requirement dependent on the GFR.     

Urinary excretion of advanced glycation endproducts in patients with type 2 diabetes and various stages of proteinuria

OBJECTIVE: The objective of the study was to detect AGE-immunoreactive proteins in urine, and to evaluate AGE excretion at various stages of diabetic nephropathy in type 2 diabetes assessed by the level of proteinuria. METHODS: AGEs were measured in 24-h urine collection of patients with normoalbuminuria (N) (n=22), microalbuminuria (Mi) (n=31), macroalbuminuria (Ma) (n=28), and overt proteinuria with elevated serum creatinine level (PC) (n=25). A competitive ELISA with polyclonal anti-AGE antibodies was used to monitor AGE excretion. RESULTS: Multiple comparison of urine AGE content among various stages of proteinuria showed significant differences (summary p<0.000). Fifty percent of samples from the group of normoalbuminuric, and only 15% of samples from the group of microalbuminuria patients were AGE negative. However, there was no significant difference in AGE excretion between the patients with persistent proteinuria and elevated serum creatinine, and those with macroalbuminuria (PC vs Ma, p=0.265). None of the samples from these two groups of patients with highest AGE content in 24-h urine was negative for AGE-immunoreactivity. In addition, the ratio between 24-h urinary AGEs and urinary albumin excretion was calculated to determine whether total 24-h urinary AGE content is an index of the toxic form of albumin released in the course of diabetic nephropathy. The ratio values were log-transformed and bivariate comparison showed significant differences between the N vs Mi (p=0.006) and Mi vs Ma (p=0.000) groups. However, there was no significant difference (p=0.407) between values in the Ma and PC groups of patients. Multiple stepwise regression analysis indicated a relationship of urinary AGE-immunoreactivity with creatinine clearance values (r=0.52, p<0.001). CONCLUSION: The study demonstrated the presence of AGE-immunoreactivity in the urine of diabetic patients with various stages of proteinuria. Study results pointed to creatinine clearance as the main predictor of AGE excretion. Therefore, the measurement of urinary AGE appears to offer limited extra information in patients with impaired renal function.     

Renal hemodynamics and renal function after catheter-based renal sympathetic denervation in patients with resistant hypertension

Increased renal resistive index and urinary albumin excretion are markers of hypertensive end-organ damage and renal vasoconstriction involving increased sympathetic activity. Catheter-based sympathetic renal denervation (RD) offers a new approach to reduce renal sympathetic activity and blood pressure in resistant hypertension. The influence of RD on renal hemodynamics, renal function, and urinary albumin excretion has not been studied. One hundred consecutive patients with resistant hypertension were included in the study; 88 underwent interventional RD and 12 served as controls. Systolic, diastolic, and pulse pressure, as well renal resistive index in interlobar arteries, renal function, and urinary albumin excretion, were measured before and at 3 and 6 months of follow-up. RD reduced systolic, diastolic, and pulse pressure at 3 and 6 months by 22.7/26.6 mm Hg, 7.7/9.7 mm Hg, and 15.1/17.5 mm Hg (P for all <0.001), respectively, without significant changes in the control group. SBP reduction after 6 months correlated with SBP baseline values (r=-0.46; P<0.001). There were no renal artery stenoses, dissections, or aneurysms during 6 months of follow-up. Renal resistive index decreased from 0.691±0.01 at baseline to 0.674±0.01 and 0.670±0.01 (P=0.037/0.017) at 3- and 6-month follow-up. Mean cystatin C glomerular filtration rate and urinary albumin excretion remained unchanged after RD; however, the number of patients with microalbuminuria or macroalbuminuria decreased. RD reduced blood pressure, renal resistive index, and incidence of albuminuria without adversely affecting glomerular filtration rate or renal artery structure within 6 months and appears to be a safe and effective therapeutic approach to lower blood pressure in patients with resistant hypertension.     

Arterial stiffness and renal impairment in non‐proteinuric type 2 diabetic patients

Aims/Introduction: Although increases in urinary protein excretion generally precede a decline in the glomerular filtration rate, non‐proteinuric renal impairment is common in patients with diabetes. In the present study, we examined the relationship between indices of arterial stiffness and renal function in type 2 diabetic patients without proteinuria. Methods: Blood sampling, 24‐h urine collection, brachial–ankle pulse wave velocity, and 24‐h ambulatory blood pressure monitoring were performed in type 2 diabetic patients without overt proteinuria. The ambulatory arterial stiffness index was calculated as (1 – the regression slope of diastolic/systolic ambulatory blood pressure). Estimated glomerular filtration rate (eGFR)was calculated using the simplified prediction equation proposed by the Japanese Society of Nephrology. Results: Of 213 non‐proteinuric patients with type 2 diabetes, 60 (28.2%) had a reduced eGFR (<60 mL/min per 1.73 m²). Although the urinary albumin excretion rate was significantly correlated with the eGFR, 34 of 152 patients with normoalbuminuria (22.4%) had a reduced eGFR. The eGFR was significantly and negatively correlated with the ambulatory arterial stiffness index and brachial–ankle pulse wave velocity, but not with 24‐h pulse pressure. Multivariate analysis revealed that increased age and increased urinary albumin excretion were independently associated with decreased eGFR. In addition, the ambulatory arterial stiffness index, but not brachial–ankle pulse wave velocity, were found to be independently and significantly associated with eGFR. Conclusions: Ambulatory arterial stiffness index is a marker for increased risk of renal failure in non‐proteinuric patients with type 2 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2011.00146.x, 2012)     

The interrelationships of radioimmunoassayable urinary albumin, renal function and diabetes

Urinary albumin, measured by radioimmunoassay, was evaluated as a method to assess early renal impairment in 76 insulin (IDD) and 36 noninsulin (NIDD)-dependent diabetic patients. Mean albumin excretion in IDD and NIDD patients was significantly higher at 23 and 12 micrograms/100 ml glomerular filtrate (GF) respectively, compared to 4 micrograms/100 ml GF in normal subjects (P less than 0.001 and P less than 0.05). Abnormal albumin excretion from 20 to 200 micrograms/100 ml GF was observed in 30% of IDD patients (P less than 0.001) and 15% of NIDD patients (P less than 0.03). Albumin excretion was significantly increased in hypertensive IDD and NIDD patients. Significant correlations between albumin excretion and age, duration of diabetes and creatinine clearance were observed, but albumin excretion did not correlate with hemoglobin A1C. These data indicate that (1) 30% of IDD patients not clinically recognized as having renal impairment have abnormal albumin excretion, (2) albumin excretion may reflect renal impairment, since albumin excretion levels independently correlate with duration of diabetes and hypertension in both diabetic subgroups and to glomerular function in NIDD patients, and (3) measurement of urinary albumin by radioimmunoassay may be the most sensitive test to evaluate early renal disease in diabetes.     

Increased urinary endothelin excretion in patients with liver cirrhosis

The urinary endothelin level in patients with chronic liver disease was determined in order to explore its possible involvement in renal function. The plasma endothelin level was significantly higher in patients with liver cirrhosis (LC) than in those with chronic hepatitis (CH) or in control patients (C). Similarly, urinary endothelin excretion in LC was significantly increased, compared with CH and C. Urinary endothelin demonstrated a significant positive correlation with creatinine clearance. The ratio of endothelin clearance/creatinine clearance did not differ statistically among the three groups. Urinary sodium excretion in LC was positively correlated with plasma endothelin, but not with urinary endothelin. Urinary endothelin excretion demonstrated a significant negative correlation with urinary kallikrein in LC. The present data suggest that increased urinary endothelin excretion in cirrhotic patients primarily depends upon elevated plasma levels of endothelin, but not renal production. Also, a possible link between endothelin and the kallikrein-kinin system in liver cirrhosis is indicated.     

Successful conservative therapy of hepatorenal syndrome with vasopressin-1-receptor antagonist ornipressin

A 47-year-old male patient with alcoholic cirrhosis Child-Pugh grade C was admitted to our center for evaluation of liver transplantation. Serum creatinine had increased from 1.6 to 4.3 mg/100 ml within the previous two weeks, creatinine clearance was 12 ml/min, and urinary sodium 12 mmol/24 h. The diagnosis of HRS type I was established. Diuretic treatment was discontinued. Following albumin infusion, central venous pressure was increased to above 10 cm H2O and dopamine (2 micrograms/kg/min) infusion was started. However, renal function did not improve. An i.v. infusion of ornipressin (POR8, Sandoz; 6 IU/h) was started and dopamine infusion continued. During a four-hour interval, urinary volume and sodium excretion doubled. Therefore treatment was continued for three weeks. After 22 days, renal function had normalized (creatinine 1.2 mg/100 ml, creatinine clearance 65 ml/min, urinary sodium 62 mmol/24 h) and diuretic therapy was resumed. No adverse effects were observed. Ornipressin/dopamine infusion was discontinued and renal function remained normal. Three weeks later, the patient underwent liver transplantation with normal renal function. Ornipressin infusion had no effect on circulating endothelin, but decreased the activation of the renin-aldosterone system and of the sympathetic activity. So far, no noninvasive therapy of hepatorenal syndrome has been established. This is the first report of successful medical treatment of HRS type I with a three-week infusion of the vasopressin-l-receptor agonist ornipressin.     

Size- and charge selectivity of glomerular filtration in Type 1 (insulin-dependent) diabetic patients with and without albuminuria

Summary Albuminuria is the first clinical event in the development of diabetic nephropathy. We assessed glomerular charge- and size selectivity in 51 patients with Type 1 (insulin-dependent) diabetes mellitus of juvenile onset and 11 healthy individuals. Patients were allocated to five groups. The urinary albumin excretion rate was normal in group D1; 30–100 mg/24 h in group D2; 101–300 mg/24 h in group D3 and greater than 300 mg/24 h in groups D4 and D5. Group D5 had elevated serum creatinine (above 110 mol/l). Glomerular filtration rate and renal plasma flow were determined by constant infusion techniques and tubular protein reabsorption by excretion of 2-microglobulin. Charge selectivity was estimated from the IgG/IgG4 selectivity index. Size selectivity was measured by dextran clearance. Dextran was measured by refractive index detection after fractionation (2 Å fractions in the range 26–64 Å) by size exclusion chromatography. IgG/IgG4 selectivity index was significantly decreased in patients with albuminuria (p<0.001). The drop in IgG/IgG4 selectivity index was found in patients with minimal albuminuria (D2) and was not accompanied by any changes in tubular function or glomerular haemodynamics. Size selectivity was significantly altered only in patients with the most advanced nephropathy (D5) as reflected by an increase in the clearance of 62 Å dextran (p<0.04). We conclude that loss of glomerular charge selectivity precedes or accompanies the formation of new glomerular macromolecular pathways in the development of diabetic nephropathy.     

One-week losartan administration increases sodium excretion in cirrhotic patients with and without ascites

Background. Losartan, a highly selective angiotensin II type 1 receptor antagonist, has been reported to have a significant portal hypotensive effect in cirrhotic patients. A recent study also showed that losartan exerted a dramatic natriuretic effect in preascitic cirrhosis. The influence of losartan on renal hemodynamics and sodium homeostasis in cirrhotic patients with ascites is unclear. This study was undertaken to evaluate the renal effects of 1-week losartan treatment in cirrhotic patients with and without ascites. Methods. All 12 patients in the study received a daily oral dose of 25 mg losartan for 7 consecutive days. Effective renal plasma flow, urine volume, creatinine clearance, 24h urine sodium excretion and fractional excretion of sodium, blood urea nitrogen, and serum creatinine were measured before and after treatment. Results. In cirrhotic patients without ascites, creatinine clearance, 24-h urinary sodium excretion, and fractional excretion of sodium were significantly increased after losartan administration. Effective renal plasma flow and serum creatinine showed almost no change after treatment. In cirrhotic patients with ascites, creatinine clearance, 24-h urinary sodium excretion, fractional excretion of sodium, and effective renal plasma flow were significantly increased after losartan administration. In addition, the magnitudes of the increases in the fractional excretion of sodium and in the 24-h urinary sodium excretion were greater in cirrhotic patients with ascites than in those without ascites. Conclusions. One-week treatment with losartan increases sodium excretion in association with an improvement of renal function in cirrhotic patients with and without ascites. The natriuretic effect was more profound in cirrhotic patients with ascites than in those without ascites. Received: May 1, 2001 / Accepted: August 24, 2001     

Variability of albumin excretion in diabetes

The variability of urinary albumin excretion was determined in 3 consecutive overnight urine collections from 152 adult type I diabetic patients (study A) and in two 1-h urine collections from 57 adult type I and type II diabetic patients, obtained at a 10-wk interval (= median, range = 2-30 wk) (study B). In both studies the coefficient of variation (CV) of urinary albumin excretion recorded as urinary albumin concentration (mg/l) was highest (study A: CV 51.1%; study B: CV 61.8%), whereas the CV of the urinary albumin/urinary creatinine ratio (mg/mmol) was lowest (study A: CV 41.9%; study B: CV 50.8%). In study A the CV of urinary albumin excretion rate (microgram/min) (CV 43.5%) did not differ from that of urinary albumin/urinary creatinine ratio. In study B, however, the CV of urinary albumin excretion rate (CV 57.2%) was higher than that of the urinary albumin/urinary creatinine ratio and of fractional albumin clearance (CV 51.0%). The variability of urinary albumin excretion was not related to its magnitude and could not be attributed to variations in plasma glucose, glycosylated haemoglobin or renal tubular glucose reabsorption. This high variability stresses the need to obtain several urine samples before the amount of albumin excreted can be reliably estimated. It is recommended that one does not use urinary albumin concentration but urinary albumin/urinary creatinine ratio or fractional albumin clearance in the assessment of urinary albumin excretion in diabetes management.