Renal Functional Reserve In Patients Research Articles

Estimation of renal functional reserve in patients with preserved renal function and coronary microvascular dysfunction

Estimation of renal functional reserve in patients with preserved renal function and coronary microvascular dysfunction

#503 The influence of the degree of liver cell failure on the functional state of the kidneys in patients with liver cirrhosis

Abstract Background and Aims Studying the influence of the severity of liver cirrhosis on the functional ability of the kidneys in patients without concomitant diseases (without diabetes mellitus and hypertension). Method The study included 38 patients with liver cirrhosis who were treated in the gastroenterology department of the Republican Scientific and Practical Center for Therapy and Medical Rehabilitation in Tashkent. The average age of patients was 54 ± 3.4 (from 33 to 65). The examined patients were divided into two groups, depending on the degree of hepatic cellular failure (according to the Child-Pugh classification) and the development of ascitic syndrome. In group 1 Liver cirrhosis without ascites (P-P class A) the number of patients was 20. In group 2 Liver cirrhosis with ascites (P-P class B) the number of patients was 18. When examining patients, we used: Clinical blood test; blood chemistry; determination of electrolytes, creatinine; general urine analysis; glomerular filtration level; Functional renal reserve (defined as the increase in glomerular filtration expressed as a percentage after the administration of Dopamine at a dose of 2-3 μg/kg/min. To assess portal hypertension, all patients underwent ultrasound examination of the organs abdominal cavity and duplex scanning of portal system vessels. Results The examined patients were analyzed for the functional state of the kidneys and its relationship with the main parameters of portal hypertension and hepatic cell failure. Comparative characteristics of the main indicators of renal function significant differences in functional parameters were revealed depending on degree of hepatic cell failure. In the group of patients with cirrhosis with ascites, there was a significant decrease in renal GFR to 77.5 ± 1.4 ml/min, in contrast to the unchanged level of GFR in the group of patients with cirrhosis without ascites—99.3 ml/min. In patients with cirrhosis without ascites, the glomerular filtration rate increases by against the background of dopamine administration was 13.5 ± 4.7% (which corresponds to the norm), in contrast to patients in the second group, where the average Renal Functional Reserve was 8.4 ± 2.8%. Changes in renal function were also characterized by a decrease in Fractional Excretion of Sodium (FENa). The reduction in FENa in the group of patients with persistent ascites. During a detailed assessment of the RFR in patients of the first group, the RFR was below normal only in 2.6 ± 2.5%, while in the second group the number of patients with the decrease in the RFR was 69.7 ± 8.1%. Study of functional renal reserve in a group of patients with cirrhosis with ascites revealed unchanged this indicator in only 10 (30.3 ± 8%). U 19 (57.5 ± 8.6%) of patients in this group, the RFR was less than 10%, and in 12.2 ± 5.7% cases of RFR was below 5%, which indicated pronounced intraglomerular hypertension and the risk of developing resistant ascites. Conclusion The present study indicates that Renal Functional Reserve (RFR) in patients with liver cirrhosis reflects the speed of effective renal plasma flow. A decrease in FPR in Child-Pugh class A liver cirrhosis was detected in 2.6% of cases, with hepatic cell failure, Child-Pugh class B in 69.7%.

#2919 Renal functional reserve assessment in patients with coronary microvascular dysfunction and preserved renal function—experience of a center

Abstract Background and Aims Renal Functional Reserve (RFR) is a field of scientific debate and may be a valuable diagnostic tool for the early detection of subclinical renal disease. According to literature, chronic kidney disease is related to cardiovascular disease (CVD), however the available data on the association of early renal dysfunction and CVD are sparse. The aim of the present study is to evaluate RFR in patients with coronary microvascular dysfunction (CMD) and preserved renal function [eGFR≥ 60 ml/min/1.73 m2 (CKD-EPI) and proteinuria< 400 mg/24 h]. Method This is a single-center, prospective study enrolling patients with INOCA. We are presenting preliminary results. In the absence of significant coronary artery stenosis, functional coronary circulation assessment was performed for all patients and we estimated coronary flow reserve (CFR) and index of microvascular resistance (IMR). In all participants, RFR was estimated by endogenous creatinine clearance after oral protein load (cooked meal, 1.2 gr/kg). Normal RFR was defined as ≥30 ml/min/1.73 m2. Also, patients with INOCA were offered 24-hour Ambulatory Blood Pressure Monitoring (ABPM). Results A total of 22 participants have been enrolled so far in study: 10 without CMD—control group [7 female, mean age: 54.4 ± 8.1 years) and 12 with INOCA—CMD group (9 female, 75%, mean age: 53.5 ± 10.3 years). CMD patients were classified into 2 groups, structural and functional endotype (CFR<2.5 and an IMR≥25 were considered abnormal). The RFR value for CMD group is 7.4 ± 6.3 ml/min/1.73 m2, while for non-CMD group 36.3 ± 5.8 ml/min/1.73 m2 (p < 0.005), relationship that remained statistically significant after controlling for confounding factors. Regarding the two endotypes of MVD, it was found that RFR for the patients with the functional endotype is 3.5 ± 2.4 ml/min/1.73 m2, while for those with the structural endotype 9.3 ± 6.9 ml/min/1.73 m2 (p-value = 0.061). Furthermore, no statistically significant relationship emerged between RFR and IMR, CFR indices (p = 0.347, p = 0.263). According to data from 24 hr ABPM, there were no significant differences in ambulatory blood pressure (systolic and diastolic) between the two endotypes of CMD (p = 0.594, p = 0.243), as well as no relationship with RFR (p = 0.553, p = 0.594). However, the proportion of non-dippers (for both SBP and DBP) was significantly higher in functional CMD endotype (p < 0.05). It was not found correlation between RFR and non-dipping phenotype, both for SBP and DBP (p = 0.561, p = 0.238). Conclusion Abnormal RFR has been observed in all patients with microvascular dysfunction. In addition, patients with functional CMD show a lower RFR value compared to those with structural. RFR is not related to blood pressure or the non-dipping pattern. Given the hypothesis that the assessment of renal functional reserve is an early diagnostic tool for subclinical renal disease, the early identification of patients with specific phenotypes—such as INOCA and pathological RFR—could contribute to the individualization of therapeutic interventions.

Renal functional reserve assessment in patients with coronary microvascular dysfuntion and preserved renal function

Abstract Funding Acknowledgements None. Introduction Renal Functional Reserve (RFR) is a field of scientific debate and may be a valuable diagnostic tool for the early detection of subclinical renal disease. According to literature, chronic kidney disease is related to cardiovascular disease (CVD), however the available data on the association of early renal dysfunction and CVD are sparse. Aim The aim of the present study is to evaluate RFR in patients with coronary microvascular dysfunction (CMD) and preserved renal function [eGFR≥ 60 ml/min/1.73m2 (CKD-EPI) and proteinuria< 400mg/24h]. Methods This is a single-center, prospective study enrolling patients with CMD. We are presenting preliminary resuts. In the absence of significant coronary artery stenosis, functional coronary circulation assessment was performed for all patients. Coronary flow reserve (CFR) and index of microvascular resistance (IMR) were measured invasively. In all participants, RFR was estimated by endogenous creatinine clearance after oral protein load (cooked meal, 1.2gr/kg). Normal RFR was defined as ≥30 ml/min/1.73m2. Also, patients with CMD were offered 24-hour Ambulatory Blood Pressure Monitoring (ABPM). Results A total of 25 participants have been enrolled so far in study: 11 without CMD - non-CMD group [7 female, 64%, mean age: 52.9±8.8 years) and 14 with INOCA – CMD group (11 female, 79%, mean age : 53.5±10.3 years). CMD patients were classified into 2 groups, structural and functional endotype (CFR<2.5 and IMR≥25 were considered abnormal). The RFR value for CMD group is 7.4±6.3 ml/min/1.73m2, while for control group 36.3±5.8 ml/min/1.73m2 (p<0.005), This difference between groups was found to be statistically significant after controlling for confounding factors. It was found that RFR value for functional CMD endotype was 3.8±2.6 ml/min/1.73m2, while for patients with structural endotype 9.6±7,2 ml/min/1.73m2 (p=0.06). Furthermore, no statistical significance was found between RFR and IMR, CFR indices (p =0.35, p =0.23 respectively). According to data from 24hr ABPM , there were no significant differences in ambulatory blood pressure (systolic and diastolic) between the two endotypes of CMD (p=NS for all), as well as no relationship with RFR (p=0.6, p=0.6 respectively) was observed. However, the proportion of non-dippers (for both SBP and DBP) was significantly higher in functional CMD endotype (p<0.05). It was not found correlation between RFR and non-dipping phenotype, for both SBP and DBP (p=NS). Conclusion Abnormal RFR has been observed in all patients with microvascular dysfunction. In addition, patients with functional CMD show a lower RFR value compared to those with structural. RFR is not related to levels of BP or the non-dipping pattern. Given the hypothesis that the assessment of renal functional reserve is an early diagnostic tool for subclinical renal disease, the early identification of patients with specific phenotypes could contribute to the individualization of therapeutic interventions.

Ultrasonographic Intraparenchymal Renal Resistive Index Variation for Assessing Renal Functional Reserve in Patients Scheduled for Cardiac Surgery: A Pilot Study

Introduction: Cardiac surgery-associated acute kidney injury (CSA-AKI) is a common complication in patients undergoing cardiac surgery. Preoperative renal functional reserve (RFR) has been demonstrated to be highly predictive of CSA-AKI. We have previously demonstrated that intraparenchymal renal resistive index variation (IRRIV) measured by ultrasound (US) can identify the presence of RFR in healthy individuals. This study aimed (1) to examine the correlation between the US IRRIV test and RFR measured through the protein loading test in patients undergoing elective cardiac surgery and (2) to determine the value of the 2 methods for predicting occurrence of AKI or subclinical AKI after cardiac surgery. Methods: Consecutive patients scheduled for cardiac surgery were enrolled for this pilot study. The protein loading test and the IRRIV test were performed in all patients 2 days before cardiac surgery. Correlation between IRRIV and RFR was tested using Pearson correlation analysis. Association between presence of RFR and positive IRRIV test, presence of RFR and AKI and subclinical AKI, and positive IRRIV test and AKI and subclinical AKI was evaluated using logistic regression analysis. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the values of IRRIV for predicting RFR, RFR for predicting AKI and subclinical AKI, and IRRIV for predicting AKI and subclinical AKI. Results: Among the 31 patients enrolled, significant association was found between IRRIV and RFR (r = 0.81; 95% CI: 0.63–0.90; p < 0.01). The association between RFR and IRRIV was described in 27/31 (87.1%) patients. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the IRRIV test were 100, 84, 60, and 100%, respectively. In ROC curve analysis, the area under the curve (AUC) was 0.80 (95% CI: 0.64–0.96). After cardiac surgery, 1/31 (3.2%) patient had AKI and 12/31 (38.7%) had subclinical AKI. RFR predicted subclinical AKI (odds ratio [OR] = 0.93; 95% CI: 0.87–0.98; p = 0.02). The sensitivity, specificity, PPV, and NPV of the RFR were 61, 88.8, 80, and 76%, respectively; the AUC was 0.75 (95% CI: 0.59–0.91). IRRIV predicts subclinical AKI (OR = 0.79; 95% CI: 0.67–0.93; p = 0.005). The sensitivity, specificity, PPV, and NPV of the IRRIV test were 46.1, 100, 100, and 72%, respectively; the AUC was 0.73 (95% CI: 0.58–0.87). Conclusion: This pilot study suggests that a positive IRRIV test can significantly predict the presence of RFR in patients scheduled for cardiac surgery. RFR measured by the protein loading test or by the US IRRIV test can predict the occurrence of subclinical postoperative AKI. The findings of this study need to be confirmed in large patient cohorts.

A call to action to evaluate renal functional reserve in patients with COVID-19.

Coronavirus disease 2019 (COVID-19) poses an unprecedented challenge to world health systems, substantially increasing hospitalization and mortality rates in all affected countries. Being primarily a respiratory disease, COVID-19 is mainly associated with pneumonia or minor upper respiratory tract symptoms; however, different organs can sustain considerable (if not terminal) damage because of coronavirus. Acute kidney injury is the most common complication of COVID-19-related pneumonia, and more than 20% of patients requiring ventilatory support develop renal failure. Additionally, chronic kidney disease is a major risk factor for COVID-19 severity and mortality. All these data demonstrate the relevance of renal function assessment in patients with COVID-19 and the need of early kidney-directed diagnostic and therapeutic approaches. However, the sole assessment of renal function could be not entirely indicative of kidney tissue status. In this viewpoint, we discuss the clinical significance and potential relevance of renal functional reserve evaluation in patients with COVID-19.

Persistent decrease of renal functional reserve in patients after cardiac surgery-associated acute kidney injury despite clinical recovery.

Cardiac surgery is a leading cause of acute kidney injury (AKI). Such AKI patients may develop progressive chronic kidney disease (CKD). Others, who appear to have sustained no permanent loss of function (normal serum creatinine), may still lose renal functional reserve (RFR). We extended the follow-up in the observational 'Preoperative RFR Predicts Risk of AKI after Cardiac Surgery' study from hospital discharge to 3 months after surgery for 86 (78.2%) patients with normal baseline estimated glomerular filtration rate (eGFR), and re-measured RFR with a high oral protein load. The primary study endpoint was change in RFR. Study registration at clinicaltrials.gov Identifier: NCT03092947, ISRCTN Registry: ISRCTN16109759. At 3 months, three patients developed new CKD. All remaining patients continued to have a normal eGFR (93.3 ± 15.1 mL/min/1.73 m2). However, when stratified by post-operative AKI and cell cycle arrest (CCA) biomarkers, AKI patients displayed a significant decrease in RFR {from 14.4 [interquartile range (IQR) 9.5 - 24.3] to 9.1 (IQR 7.1 - 12.5) mL/min/1.73 m2; P < 0.001} and patients without AKI but with positive post-operative CCA biomarkers also experienced a similar decrease of RFR [from 26.7 (IQR 22.9 - 31.5) to 19.7 (IQR 15.8 - 22.8) mL/min/1.73 m2; P < 0.001]. In contrast, patients with neither clinical AKI nor positive biomarkers had no such decrease of RFR. Finally, of the three patients who developed new CKD, two sustained AKI and one had positive CCA biomarkers but without AKI. Among elective cardiac surgery patients, AKI or elevated post-operative CCA biomarkers were associated with decreased RFR at 3 months despite normalization of serum creatinine. Larger prospective studies to validate the use of RFR to assess renal recovery in combination with biochemical biomarkers are warranted.

Cardiovascular risk stratification and renal functional reserve in patients with essentials hypertension

The article is devoted to the role of renal functional reserve (RFR) in essentials hypertension (EH) in the diagnosis of early kidney damage. Particular attention is paid to the effect of cardiovascular (CV) complications on RFR.The objective: to assess the functional state of the kidneys in patients with EH I stage and different total risk of CV complications.Materials and methods. The study involved 80 people with the established diagnosis EH of I stage of the I–II grade according to the WHO/ISH, 2003 (World Health Organization/International Society of Hypertension) and Order of the Minister of Health from May, 24, 2012 No.384 [2, 4, 8], in age from 18 to 60 years (women – 28 (35%), the average age is 40,1 (35,0–56,0) years, men – 57 (71%), average age – 40,2 (37,0–53,0) years. The average duration of EH stage I was 3,5 (1,2–5,0) years. Non-inclusion criteria were acute infectious diseases, symptomatic arterial hypertension, valvular heart disease, cardiac rhythm disturbances, chronic heart failure, chronic kidney disease, diabetes mellitus, coronary heart disease. Patients at the time of inclusion in the study did not take antihypertensive therapy. All patients underwent a comprehensive examination: a history, clinical examination and body anthropometric measurements (height, weight, waist and hip circumference and waist-to-thigh ratio (WTR)), complete blood count and urine tests, biochemical blood test (total protein, urea, creatinine, glucose, lipid profile, cystatin C), albumincreatinine ratio (ACR) in urine, ABPM, ECG, Echo-CG, ultrasound of carotid arteries, ophthalmoscopy. A risk factor count was used to assess the overall risk of CV complications in hypertension. In addition, RFR was determined the method water and salt load (under patentUkraine42,860) [1]. Statistical analysis of the results was carried out on a computer using the Microsoft Excel 2016 software package and IBM SPSS Statistics (version 21,USA).Results. When stratifying the risk, it was found that 56% of patients had a high risk, 20% of patients had an average risk and 24% had low risk of developing CV complications. In this case, high risk patients had 3–5 risk factors, the average – less than 3 risk factors, and patients with low risk had 1–2 or had no risk factors at all. Of all the risk factors most often met dyslipidemia, male sex, abdominal obesity and family history of premature CVD. In the course of the study, it was clear that even in patients with a low risk of CV complications, kidney damage was noted in the form of a reduced and depleted RFR.Conclusions. An important study of renal damage in EH I stage is the definition of a functional renal reserve. In patients with even a low risk of CV complications in EH I stage, a reduced and depleted RFR is defined. The most commonly depleted RFR was detected in patients with a high risk of developing CV complications.

Renal functional reserve in children with a solitary functioning kidney and chronic kidney disease

O bjective – To examine renal functional reserve (RFR) and blood pressure (BP) in children with a solitary functioning kidney (SFK) and stage 1-3 chronic kidney disease (CKD). M ethod – RFR was measured in 48 children with SFK and in 10 healthy children, as the difference between unstimulated and stimulated clearance of endogenous creatinine by a meat-free oral protein load (OPL). Cimetidine was given 48 h prior to the measurement when the study subjects were on a diet free of meat, fish and poultry. Serum cystatin C and urinary protein (UPRT)/urinary creatinine (UCr) were examined before and 2 hours after OPL. BP was determined by office and by 24-h ambulatory BP monitoring (ABPM). R esults – The majority of the patients (79.6%) had congenital SFK, while the remaining had acquired SFK due to unilateral nephrectomy. Sixteen patients had CKD1, 19 patients had CKD2 and 13 had CKD3. The patients and controls did not differ in terms of age, gender, body size, office and 24-h blood pressure readings and basal GFR. Kidney size was greater and serum cystatin C was higher in patients than in controls. Increased proteinuria and arterial hypertension were found in 24.3% and 18.9% of the patients, respectively. Nocturnal hypertension was more common than that during the daytime. After OPL, GFR significantly increased, more in controls than in patients. Among the patients, the RFR was the highest in the CKD3 group. Conclusion – OPL induced an increase in GFR above its basal value. This response was higher in healthy children than in those with SFK. The positive relationship between RFR and CKD stage and the highest RFR in CKD3 patients suggests well preserved renal functional reserve in patients with moderate renal failure. ABPM is necessary for BP evaluation in children with SFK.

The state of renal functional reserve in patients with diabetes mellitus type 2

40 insulin-dependent patients, 14 men (35 %) and 26 women (65 %) aged from 39 to 76 years, with diabetes mellitus of the type 2 were diagnosed with the development of chronic kidney disease of 1-3 stages according to the urinary symptoms, mainly albuminuria (50 %), hypercreatininaemia (30 %) and declining of glomerular filtration rate &lt; 60 ml / min (37,5 %). To determine the state of renal functional reserve we used the method of calculation according to the water – salt load with 0,5 % NaCl in a volume of 0.5 ml/kg of body weight. It was found that in the majority of patients (92,5 %) renal functional reserve was in the normal range and even exceeded it, averaging 178,5 + 8,9 %. The magnitude of renal functional reserve does not depend on the performance of albuminuria, glycosuria, concentration of glycated hemoglobin HbA1c and hypercreatinaemia. Based on these findings we concluded that in patients with diabetes mellitus damaged nephrons function in kidneys, however reduction of their amount does not yet take place in this period of disease.

Intrarenal hemodynamics and impaired tubular functions in patients with systemic lupus erythematosus

Система комплексной поддержки и сопровождения научного журнала Elpub позволяет запустить двуязычный сайт журнала со встроенной системой электронной редакции в соответствии с лучшими издательскими практиками, а так же предусматривает техническую и методическую поддержку со стороны специалистов НЭИКОН.

Renal Functional Reserve in Patients with Recently Diagnosed Type 2 Diabetes mellitus with and without Microalbuminuria

Background/Aims: During the first 10 years, two thirds of the patients with type 2 diabetes mellitus (DM) have microalbuminuria (MA). Functional renal reserve (FRR) and its relationship with proteinuria and metabolic control are unknown at the early phases of disease. We investigated the frequency of MA in recently diagnosed type 2 DM patients, and its association with FRR. Methods: We studied 181 type 2 DM patients with less than 6 months since diagnosis. Renal volume, MA, glomerular filtration rate (GFR) and renal plasma flow (ERPF) were evaluated before and after an acute oral protein load in 28 type 2 DM patients (14 with, and 14 without MA), and in 7 healthy subjects. Results: A total of 10.6% of the patients had MA. MA patients had higher cholesterol and triglyceride levels than those normoalbuminuric. Twenty recently diagnosed type 2 diabetic patients showed high basal GFR. Twelve of them had MA and insulin resistance. After the acute oral protein load, the control subjects and the patients without MA increased their GFR and their ERPF. The group with MA did not. Conclusions: Seventy-five percent of the patients were hyperfiltering. Normoalbuminuric patients had larger increase in GFR and ERRPF than MB patients. We conclude that FRR measurement can be an important tool for the diagnosis of latent diabetic nephropathy.

J011 Abnormalities of renal functional reserve in patients with mild heart failure are corrected by losartan

J011 Abnormalities of renal functional reserve in patients with mild heart failure are corrected by losartan

Renal functional reserve in patients with severe chronic obstructive pulmonary disease.

BACKGROUND: Renal functional reserve is the normal increase in renal blood flow after a protein load, and reduced or absent renal functional reserve is an early index of renal impairment....

Renal Functional Reserve in Patients with IgA Glomerulopathy

Seven patients with histologically proven IgA nephropathy and modest impairment of renal function, and 2 patients with IgA nephropathy and nephrotic syndrome were investigated, compared to a control group of 9 healthy individuals, to study the effects of amino acids on glomerular and tubular function, and to evaluate renal functional reserve in IgA nephropathy with different clinical course. Inulin and PAH clearances were used to evaluate glomerular filtration rate (GFR) and effective renal plasma flow (ERPF); proximal and distal tubular fluid delivery and reabsorption were measured by lithium clearance, before and after submission of a standardized amino acid solution. GFR and ERPF increased significantly during amino acid load in healthy individuals and patients without nephrotic syndrome, while filtration fraction (GFR/ERPF) remained constant. Lithium clearance (CLi) and fractional lithium excretion (CLi/GFR) rose significantly in both groups, whereas the reabsorbed volume of fluid in the proximal tubule did not change. In the distal tubule, fractional volume excretion decreased significantly during amino acid load whereas the reabsorbed volume significantly increased. Baseline values of the two groups did not differ significantly. Two patients with nephrotic course of IgA nephropathy showed a distinct decrease in glomerular and tubular function, and a loss of renal functional reserve after amino acid load. Despite distinct alterations in renal biopsy, IgA nephropathy without nephrotic course presents with a still adequately preserved kidney function and renal functional reserve. A single determination of renal function with noninvasive functional tests does not give valid prognostic information concerning glomerular and tubular function. Therefore, a repeated measurement of renal function at defined intervals might reveal clinical progression of renal disease. The results of the lithium clearance might indicate an increase in tubular function after amino acid load, indicating a tubular adaptation in state of hyperfiltration.

Renal funtional reserve in kidney transplant recipients

In the last few years different authors have observed that kidney transplant recipients with good organ function do not have a renal functional reserve (RFR). This condition is accompained by a high glomerular filtration rate (GFR) [2–6]. We studied RFR in patients with very good organ function under different immunosuppressive therapies, who were divided into groups based on the presence or absence of RFR.

Cyclosporin A abolishes renal reserve capacity.

Renal functional reserve (RFR) was investigated in a group of renal transplant recipients taking cyclosporin A (CyA) immunosuppressive therapy. Nine patients received a 93 g oral protein load containing 5983 mg of glycine. GFR and ERPF were measured using isotope infusions of 51Cr EDTA and 125I OIH, respectively, before and for 3 h after the meal. Patients studied demonstrated a wide range of baseline GFRs (20.9-89.5 mL/min, mean 50.09 mL/min). However, few patients demonstrated an individual RFR, regardless of original level of function. Overall, no significant change in either GFR or ERPF was demonstrated after the protein stimulus. CyA is known to alter intrarenal prostanoid synthesis in favor of vasoconstriction and RFR is thought to be mediated by prostanoids. Therefore a mechanism for the absence of RFR in patients receiving CyA therapy is suggested.

Renal funtional reserve in kidney transplant recipients.

In the last few years different authors have observed that kidney transplant recipients with good organ function do not have a renal functional reserve (RFR). This condition is accompained by a high glomerular filtration rate (GFR). We studied RFR in patients with very good organ function under different immunosuppressive therapies, who were divided into groups based on the presence or absence of RFR.

Renal functional reserve in patients with essential hypertension: Effect of inhibition of the renin-angiotensin system

1. Urinary albumin excretion and the effect of an acute oral protein load (a meat meal) on glomerular filtration rate ('renal functional reserve') were evaluated in 15 essential hypertensive patients with preserved renal function and compared with 12 normal subjects. 2. Seven patients had microalbuminuria (greater than 30 mg/day) that was not correlated with blood pressure values. 3. After an oral protein load, an average increase of 20% in glomerular filtration rate (from 91 +/- 19 to 110 +/- 27 ml min-1 1.73 m-2 was found in the hypertensive patients. This change was not statistically different from that observed in normal controls (from 102 +/- 7 to 124 +/- 9 ml min-1 1.73 m-2). The glomerular response in hypertensive patients was independent of age, duration of hypertension, blood pressure, plasma renin activity, urinary albumin excretion and retinal vascular alterations. 4. All patients were re-evaluated after 6 weeks treatment with a new orally active angiotensin-converting enzyme inhibitor, benazepril. Systolic, diastolic and mean blood pressures were lowered in all the patients, but the drug did not affect the glomerular response to acute protein ingestion or the magnitude of urinary albumin excretion. 5. The findings of a normal 'renal functional reserve' and a lack of change in both urinary albumin excretion and the glomerular response after angiotensin-converting enzyme inhibition cast doubt on the existence of increased intraglomerular pressure in hypertensive patients.

糸球体機能と腎予備能

Protein intake has been shown to raise glomerular filtration rate (GFR). The difference between peak and baseline GFR following acute protein load indicates renal functional reserve (RFR). In this paper, we review 1) normal glomerular function and its regulating factors, 2) the concept of RFR and the mechanism by which the acute protein load induces hyperfiltration response in healthy subjects and 3) the RFR in patients with renal disease.