Urate Transporter ABCG2 Function and Asymptomatic Hyperuricemia: A Retrospective Cohort Study of CKD Progression.

RATIONALE & OBJECTIVE: Treatment of asymptomatic hyperuricemia is not commonly implemented. However, it is unclear whether urate deposition that begins during asymptomatic hyperuricemia can induce nephropathy. Dysfunction of ATP-binding cassette subfamily G member 2 (ABCG2), a urate efflux transporter, leads to elevated serum uric acid concentration (SUA). We investigated the association between asymptomatic hyperuricemia and decreased estimated glomerular filtration rate (eGFR), and the impact of ABCG2 on this relationship. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: 1,885 Japanese adults undergoing routine health care follow-up between 2007 and 2017 who had eGFR ≥60 mL/min/1.73 m2, of which 311 had asymptomatic hyperuricemia (SUA >7.0 mg/dL). Study participants were classified into 3 categories of estimated ABCG2 function (full, 75%, and ≤50% function). PREDICTORS: Baseline SUA and estimated ABCG2 function. OUTCOME: Change in eGFR over time. ANALYTICAL APPROACH: Linear mixed-effect models were used to analyze the relationship between asymptomatic hyperuricemia, ABCG2 function, and eGFR decline. RESULTS: Asymptomatic hyperuricemia was negligibly associated with eGFR decline overall. However, among those with eGFR 60-89 mL/min/1.73 m2 and ≤50% ABCG2 function, eGFR decline was associated with asymptomatic hyperuricemia (P = 0.03). ABCG2 was not associated with eGFR reductions when the SUA was <6.0 mg/dL. Among participants with SUA ≥6.0 mg/dL and eGFR 60-89 mL/min/1.73 m2, ≤50% ABCG2 function was associated with approximately 1.2-fold faster eGFR decline compared with fully functional ABCG2 (P = 0.02). Among the participants with SUA ≥6.0 mg/dL and eGFR 60-89 mL/min/1.73 m2, the adjusted eGFR slopes (given as mean ± standard error of the mean, in mL/min/1.73 m2 per year) were -0.946 ± 0.049, -1.040 ± 0.046, and -1.148 ± 0.069 for full, 75%, and ≤50% ABCG2 function, respectively. LIMITATIONS: Lack of measurement of urinary urate and uremic toxins that are known to be transported by ABCG2, and no independent validation cohort. CONCLUSIONS: Asymptomatic hyperuricemia was not associated with eGFR decline, except when in the presence of ≤50% ABCG2 function. PLAIN-LANGUAGE SUMMARY: The urate transporter ABCG2 is a protein that regulates serum urate concentrations; when dysfunctional, it can lead to elevated serum concentrations of this compound (ie, hyperuricemia). Although persistent hyperuricemia induces gout and kidney injury, the effects on organs during the asymptomatic phase have yet to be established. Therefore, to clarify the relationship between ABCG2, asymptomatic hyperuricemia, and kidney function, we conducted a retrospective cohort study of 1,885 healthy participants, including 311 participants with asymptomatic hyperuricemia. We found that the coexistence of asymptomatic hyperuricemia and severe ABCG2 dysfunction was associated with the age-dependent decline in kidney function. We concluded that asymptomatic hyperuricemia represents a risk factor for chronic kidney disease, at least in individuals with highly dysfunctional ABCG2. This new finding highlights the potential importance of ABCG2 in the pathogenesis of hyperuricemia-induced kidney injury.

Association between polymorphism at IGF-1 rs35767 gene locus and long-term decline in renal function: a Japanese retrospective longitudinal cohort study.

BACKGROUND: Insulin-like growth factor-1 (IGF-1) acts on glucose and protein metabolism and human growth and also influences blood pressure and renal function. This study investigated whether the single-nucleotide polymorphism of IGF-1, rs35767, plays a role in metabolic syndrome indicators, including blood pressure, glucose metabolism, uric acid levels, and renal function. METHODS: In this retrospective longitudinal cohort study, blood samples from 1506 Japanese individuals were collected and used for genotyping for variant rs35767: T > C in the IGF-1 upstream promoter. Data were analyzed to identify associations between IGF-1 genotypes and patient biochemical parameters, including the components of metabolic syndrome and the long-term change in renal function. RESULTS: The cohort rs35767 genotypes included 650 CC carriers (43.2%), 687 TC carriers (45.6%), and 169 TT carriers (11.2%). Multiple regression analysis revealed no association between IGF-1 genotype and blood pressure, glycated hemoglobin level, and serum uric acid level. However, in females, blood pressure was negatively correlated with the TT genotype. Longitudinal observation revealed that the decline in eGFR over 10 years was greater in TT (- 18.51 ± 1.04 mL/min/1.73m2) than in CC carriers (- 16.38 ± 0.52 mL/min/1.73m2; P < 0.05). CONCLUSION: The present study suggests that renal function declines faster in individuals with the TT genotype at the IGF-1 rs35767 locus than in those with the CC genotype, suggesting that the TT genotype is associated with the long-term chronological decline in renal function.

Correction to: Dotinurad: a novel selective urate reabsorption inhibitor as a future therapeutic option for hyperuricemia.

In the original publication of the article the presentation of Table 1 was incorrectly published.

Dotinurad: a novel selective urate reabsorption inhibitor as a future therapeutic option for hyperuricemia.

Gout is a chronic inflammatory disease caused by precipitation of urate crystals in the joints, kidneys, and urinary tract. Independent of urate deposition disorders, recent studies have shown a positive association between circulating uric acid (UA) levels and cardiovascular (CV) diseases. These results indicate that UA is a precipitating factor of both gout and the progression of CV diseases, including hypertension and/or chronic kidney disease (CKD). A large body of evidence has shown that UA-lowering therapies are effective in preventing the progression of hypertension/CKD and that a causal relationship exists between serum UA level and CV diseases. Despite the urgent need for effective UA-lowering drugs that can be used to obtain better therapeutic outcomes and prognosis, only few drugs have been developed in the past decades. Recently, febuxostat and topiroxostat, which are xanthine oxidoreductase inhibitors, were developed and used in clinical practice. Of note, after the approval of lesinurad, which is a urate transporter-1 (URAT-1) inhibitor, in the United States in 2015, dotinurad (Fig. 1), a novel promising drug with selective UA reabsorption inhibitory property, was recently developed in Japan in 2018. Dotinurad is indicated for patients with hyperuricemia/gout as most patients with hyperuricemia are classified into "underexcretion type", which requires the inhibition of URAT-1 to excrete excess UA via the kidney. Focusing on dotinurad, the present study highlighted the multifaceted preliminary new trials that assessed for drug efficacy and safety, pharmacokinetics (PK) according to age and gender, the presence or absence of liver and kidney disorders, drug interactions with NSAID, and non-inferiority of dotinurad to either febuxostat or benzbromarone. A series of studies included in this supplemental review indicate that dotinurad reduces serum UA levels, and its efficacy and safety are similar to those of other UA-lowering agents currently used even in hyperuricemic patients with various clinical conditions. Moreover, two exploratory studies with a small sample size were conducted to compare PK parameters between patients with overproduction- and underexcretion-type hyperuricemia, and results showed that the effects of UA-lowering agents were comparable between the two subtype groups.Fig. 1Chemical structural formula of dotinurad.

A Potential Mechanism of Cardio-Renal Protection with Sodium-Glucose Cotransporter 2 Inhibitors: Amelioration of Renal Congestion.

BACKGROUND: This review considers anew the etiology of the cardio-renal protective effect of sodium-glucose cotransporter 2 (SGLT2) inhibitors by extending the discussion to renal congestion, inherent in diabetic kidney disease (DKD) even at an early stage of nephropathy in which heart failure (HF) or salt and water accumulation is asymptomatic. SUMMARY: The interstitial fluid (IF) space of the kidney space plays a crucial role for tubulointerstitial inflammation, renal hypoxia, and ischemic injury, which often leads to renal progression. In DKD, as a result of hyperglycemic milieu, excessive salt and water can be accumulated in the IF space, creating renal congestion. I hypothesize that SGLT2 inhibitors cause a shift in extracellular water from the IF space to the intravascular space to compensate for the SGLT2 inhibitor-induced hypovolemia. This decrease in IF volume ameliorates the IF space milieu and may reduce inflammation, hypoxia, and ischemic injury. Message: The present review proposes a novel theory; unlike other hypoglycemic agents or diuretics, SGLT2 inhibitor could protect DKD from failing by improving latent renal congestion even without symptomatic HF.

Protection of the kidney with sodium-glucose cotransporter 2 inhibitors: potential mechanisms raised by the large-scaled randomized control trials.

This communication provides a current overview on the renal protective effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors in diabetics. Following the epoch-making publications, the CANVAS Program and the EMPA-REG OUTCOME trial, numerous literature has discussed the mechanisms by which SGLT2 inhibition exerts its cardio-renal protective effects. Some of them reached agreement, while others did not. This review focuses on the hemodynamic aspect and the remaining potential factors relevant to the renal protection which have not been so much taken up by other review papers. Questions unanswered include factors of uric acid, lipids, erythropoiesis and oxidative stress, salt and sympathetic nerve, and the Na-H exchanger in heart and kidney.

Gender interaction of uric acid in the development of hypertension.

AIM: The present study explored the gender interaction on the risk of uric acid in the new development of hypertension. STUDY DESIGN: A longitudinal retrospective cohort. SUBJECTS & METHODS: A total of 5,807 individuals with an average age of 38 ± 7 years old were recruited. Individuals whose blood pressure rose more than 140/90mmHg or those who newly commenced antihypertensive treatment were defined as a new onset of hypertension. Cox regression analysis was employed for the analysis. RESULTS: During the 10-years follow-up, 42.8% of men and 22.2% of women had developed hypertension. Factors to predict the hypertension development were male gender, older age, higher BMI, higher uric acid, and higher mean blood pressure. An association between higher uric acid levels and higher incidence of hypertension remained statistically significant in women in a multivariate model adjusted for various clinical variables (Hazard ration (HR), 1.180; 95%CI, 1.018 to 1.369), whereas such association was not found in men (HR, 1.034; 95%CI, 0.994 to 1.075). The interaction between the two genders reached statistical significance (p for interaction = 0.007). CONCLUSION: Higher uric acid is associated with the incident hypertension in the both genders. Women are more susceptible to the development of hypertension than men.

Usefulness of combination therapy with Daclatasvir plus Asunaprevir in chronic hepatitis C patients with chronic kidney disease.

AIM: Combination therapy with Daclatasvir (DCV) plus Asunaprevir (ASV) has been proven effective in patients with chronic hepatitis C virus (HCV) infection. However, little is known as to the effect of this therapy in patients with reduced renal function. Focusing on CKD patients whose renal function has declined, the present trial addresses the efficacy and safety of this combination therapy in CKD patients with reduced estimated glomerular filtration rate (eGFR). MATERIALS AND METHODS: The study design is a single-center, retrospective longitudinal observational study enrolling 106 patients with (n = 29) or without (n = 77) CKD. After the treatment with combined DCV with ASV for chronic HCV genotype 1b, patients were followed for a total of 48 weeks and the comparison was made in clinical parameters between the two groups. RESULTS: (1) The majority of patients in both groups achieved sustained virological response at 24 weeks (90.8 % in the non-CKD group, and 93.1 % in the CKD). (2)The reduction rate in HCV-RNA levels 2 weeks after commencing the treatment was faster in the CKD group than that in the non-CKD group (81.8 vs. 79.2 %, p < 0.01). (3) Three patients in the CKD group and 6 patients in the non-CKD group withdrew from the treatment because of the adverse events. CONCLUSION: Combination therapy with DCV plus ASV for chronic HCV genotype 1b infection is useful and tolerable, not only in patients with normal eGFR, but also in those with CKD with declined eGFR. Viral eradication at an early phase of the treatment appears to be faster in CKD patients.

Effectiveness of a fixed combination formula of ombitasvir/paritaprevir/ritonavir for hepatitis C virus infection in patients on maintenance haemodialysis.

A fixed-dose formula that combines Ombitasvir (OBV), Paritaprevir (PTV) and Ritonavir (RTV) has been launched into the field of anti-HCV therapy in Japan for patients infected with HCV genotypes 1 and 2 in 2015. However, little is yet known as to the efficacy and safety of this novel therapy in patients on maintenance haemodialysis (HD). The present report describes a preliminary experience in 10 patients (five males and five females) who underwent maintenance HD. All of them had HCV genotype 1b, without having the resistance-associated variants at Y93 or L31 in the nonstructural proteins 5A (NS5A) region. After the treatment, eight patients successfully achieved virus eradication and sustained a virological response at 12 weeks (SVR12). In addition, mac-2 binding protein glycosylation isomer (M2BPGi), a biomarker for liver fibrosis, was reduced after the therapy. Two patients withdrew from the therapy due to the development of erythema multiforme and a strong drowsiness, respectively. These results suggest that triple therapy combining OBV, PTV and RTV is effective in achieving SVR12 in most of the HCV-infected patients on HD. In addition, this combination therapy contributed to retard the progression of liver fibrosis. However, we suggest that further trial will be required to establish its clinical efficacy and safety.

Serum uric acid and the incidence of CKD and hypertension.

BACKGROUND: Uric acid (UA) levels correlate positively with the prevalence of chronic kidney disease (CKD) and/or hypertension. We tested the hypothesis that UA may also have a link to a new incidence of CKD and hypertension. METHODS: Study design is a cohort study and the predictor is UA levels. Of the 15,470 screened cases, 8223 participants without CKD were eligible for the analysis of the incidence of CKD. Among these CKD candidates, 7569 participants were eligible for the analysis of the new development of hypertension. The observation period was 4 years. RESULTS: Relationship of UA with new cases of CKD. Higher UA levels had a closer association with the new development of CKD; 1.1 % (UA < 5 mg/dL), 1.5 % (5.0-5.9 mg/dL), 1.7 % (6.0-6.9 mg/dL), and 3.4 % (≧7 mg/dL), respectively (p < 0.001 by the Chi-square test). Cox proportional hazard analysis showed that the estimates of the CKD development were eGFR [Hazard Ratio (HR) 0.816, 95 % confidence intervals (CI) 0.791-0.840] and male gender (HR 0.562, 95 % CI 0.322-0.982). UA levels and new development of hypertension. Higher UA levels had a closer association with the new development of hypertension; 5.0 % (UA < 5 mg/dL), 8.9 % (5.0-5.9 mg/dL), 10.6 % (6.0-6.9 mg/dL), and 11.8 % (≧7 mg/dL), respectively (p < 0.001 by the Chi-square test). Cox proportional hazard analysis showed that the estimates of the hypertension development were BMI (HR 1.190, 95 % CI 1.155-1.226), age (HR 1.021, 95 % CI 1.010-1.032), HDL-cholesterol (HR 1.013, 95 % CI 1.007-1.019), male gender (HR 1.791, 95 % CI 1.338-2.395), UA level (HR 1.112, 95 % CI 1.024-1.207), and eGFR (HR 1008, 95 % CI 1.002-1.013). Furthermore, the logistic analysis showed that the odds ratio (OR) to estimate hypertension in the high UA group (UA ≧ 7 mg/dL; OR 1.33, 95 % CI 1.01-1.80) was greater than that in the low UA group (UA < 5 mg/dL). Kaplan-Meier analysis also confirmed the finding that the higher the UA levels the greater the hypertension development (p < 0.001 by the Log-rank test and Cox proportional hazard analysis). CONCLUSION: High UA levels are associated with the new development of hypertension, but not with the incidence of CKD.

Effect of aliskiren in chronic kidney disease patients with refractory hypertension undergoing hemodialysis: a randomized controlled multicenter study.

BACKGROUND: Applying a direct renin inhibitor (DRI) to advanced stage chronic kidney disease (CKD) patients is a matter of controversy. The purpose of this study was to evaluate the effect of the DRI, aliskiren, in patients with therapy-resistant hypertension undergoing hemodialysis (HD). METHODS: The study was a prospective, randomized multicenter trial exploring the antihypertensive effect of aliskiren in comparison with amlodipine, a calcium channel blocker, in patients undergoing HD. A total of 83 participants whose blood pressure (BP) had previously been treated with more than one antihypertensive agent and not having achieved the BP goal of <140/90 mmHg were randomly assigned to either aliskiren 150 mg or amlodipine 5 mg as an add-on therapy. RESULTS: A significant decrease in pre-dialysis clinic BP and home BP was found only in the amlodipine group and not in the aliskiren group. In contrast, there was a significant decrease in atrial natriuretic peptide (ANP) in the aliskiren group but not in the amlodipine group. N-terminal pro-B-type natriuretic hormone remained unchanged in both groups. Aliskiren significantly reduced angiotensin I and II, plasma renin activity, and increased plasma renin content. However, such changes were not observed in the amlodipine group. CONCLUSION: Amlodipine, not aliskiren, effectively reduces BP in CKD patients with refractory hypertension undergoing HD. Aliskiren suppresses the renin-angiotensin system and reduces ANP. Whether the DRI is beneficial in improving cardiovascular events in patients undergoing HD remains to be elucidated in future studies.

Monitoring of body water composition by the simultaneous use of bioelectrical impedance analysis and Crit-Line(®) during hemodialysis.

BACKGROUND: Bioelectrical impedance analysis (BIA) is a non-invasive method to estimate total body water (TBW) and extracellular water (ECW) volume. Crit-Line(®) (CL), on the other hand, assesses intravascular water (IVW) volume. We evaluate continuous changes in body water composition during hemodialysis (HD) with concurrent use of BIA and CL. METHODS: BIA at the start and the end of the HD session was measured using a BIA device. To investigate the shifting pattern of body water composition, patients were subjected to simultaneous monitoring of BIA with CL. RESULTS: Both TBW resistance (Rt) and ECW resistance (Re) increased in response to changes in the ultrafiltration (UF) ratio. There was a positive correlation between ΔRe/Rt and the UF ratio, and the ratio of Re/Rt at the end of HD was significantly higher than that at the start of HD. Simultaneous monitoring of BIA with CL showed a parallel shift of the change in the Re (ΔRe) and the change in hematocrit (ΔHt). In one patient with increasing inflammatory response, change in ΔHt was dissociated from change in ΔRe. One hyponatremic patient showed a different pattern of changing ΔRe between the first half and the latter half of the HD session. CONCLUSION: Our study suggests that the concurrent use of BIA and CL may be a useful technique to simulate water shift patterns across the different compartments in HD.

Combined therapy with peritoneal dialysis and hemodialysis: a multicenter retrospective observational cohort study in Japan.

BACKGROUND/AIMS: Combining peritoneal dialysis (PD) and hemodialysis (HD) has been common treatment option in Japan. METHODS: In this retrospective, multicenter, observational study, the clinical characteristics and outcomes of 104 patients (57 ± 11 years, males 72%) who had switched from PD alone to combined therapy with PD and HD were studied. Clinical parameters were measured at baseline and after 3 months of combined therapy. RESULTS: At baseline, urine volume, dialysate-to-plasma ratio of creatinine (D/P Cr), and total Kt/V were 150 ml/day (range: 0-2,000 ml/day), 0.67 ± 0.11, and 1.8 ± 0.4, respectively. During the first 3 months of combined therapy, body weight, urine volume, serum creatinine level, and D/P Cr decreased, whereas hemoglobin levels increased. CONCLUSIONS: In patients where PD does not result in acceptable outcomes, combined therapy with PD and HD may have potential benefits in terms of dialysis adequacy and hydration status. Video Journal Club "Cappuccino with Claudio Ronco" at http://www.karger.com/?doi=368389

[Relationship between serum uric acid levels and muscle strength/volume: a new insight from a large-scale survey].

AIM: Serum uric acid (UA) concentration is regulated by its production in the liver and/or intestine and its rate of excretion from the kidneys. However, little is known about skeletal muscle involvement in determining the physiological UA level. The present trial explores whether muscle strength and/or muscle volume is associated with UA levels. MATERIAL & METHODS: Muscle strength was evaluated in terms of grasping power calculated as an average of right and left hand measurements in relation to other parameters in 14,333 subjects (median age; 41.2 years), who were recruited to the study. Skeletal muscle volume was calculated based on the bioimpedance method by subtracting estimated fat volume plus estimated bone weight from the total body weight. RESULTS: 1) Multiple regression analyses to explain the association with UA levels (dependent variable) revealed that BMI, BUN, triglyceride, muscle strength, AST, age and sex are independent variables. 2) Higher UA levels (assessed as 4 UA quartiles) are associated with higher muscle volume, muscle strength, BMI, DBP, and serum creatinine (Cr) concentration. 3) Greater DBP (assessed as 2 UA categories) was associated with higher BMI, muscle strength, muscle volume, UA levels and serum Cr concentration. 4) Regression coefficient "t" for muscle strength was the largest among the other parameters including serum Cr concentration in the UA level ranging from 5.5 to 6.5 mg/dL. CONCLUSION: There was an association between muscle strength/volume and UA levels in the near physiological UA range, suggesting that the circulating UA levels can be, at least in part, controlled by its production in the skeletal muscles.

Antihypertensive effect of a fixed-dose combination of losartan/hydrochlorothiazide in patients with uncontrolled hypertension: a multicenter study.

BACKGROUND: Achieving adequate blood pressure (BP) control often requires more than one antihypertensive agent. The purpose of this study was to determine whether a fixed-dose formulation of losartan (LOS) plus hydrochlorothiazide (HCTZ) (LOS/HCTZ) is effective in achieving a greater BP lowering in patients with uncontrolled hypertension. METHODS: The study was a prospective, multicenter, observational trial exploring the antihypertensive effect of a single tablet of LOS 50 mg/HCTZ 12.5 mg. A total of 228 patients whose BP had previously been treated with more than one antihypertensive agents without having achieved BP goal below 130/80 mmHg enrolled in the study. RESULTS: A significant decrease in systolic and diastolic BP was observed in both clinic and home measurement after switching from the previous treatment to LOS/HCTZ. There was a significant decrease in both B-type natriuretic peptide (BNP) and urinary albumin creatinine (Cr) excretion ratio (ACR), especially in patients with elevated values. In contrast, there was a significant increase in serum Cr concentration in conjunction with a decrease in estimated glomerular filtration rate (eGFR). Overall serum uric acid (UA) concentration increased, whereas in patients with hyperuricemia there was a significant reduction in this value. CONCLUSION: Switching to LOS/HCTZ provides a greater reduction in clinic and home BP in patients with uncontrolled hypertension. This combination therapy may lead to cardio-, reno protection and improve UA metabolism.

Augmented antihypertensive effect of a fixed combination formula of candesartan and hydrochlorothiazide combined with furosemide in a patient on peritoneal dialysis.

A 38-year-old female patient on peritoneal dialysis (PD) due to type 1 diabetic nephropathy with a well-preserved residual renal function did not respond well to the conventional antihypertensive therapy consisting of candesartan, furosemide, and bunazosin. Switching candesartan for a fixed combination formula of candesartan plus hydrochlorothiazide (HCTZ) while the rest of the other two agents remained unchanged led to the remarkable reduction in both systolic and diastolic blood pressure (BP) without significant changes in the cardiothoracic ratio (CTR), body weight (BW), and residual renal function. This case suggests that when used in combination, diuretics acting on different functional segment of the nephron hold greater potential for enhanced antihypertensive effect, especially in patients on PD whose residual renal function is well preserved. A small dose of HCTZ with an angiotensin II receptor blocker (ARB) may partially explain the therapeutic benefit of this combination therapy in terms of a reliable hypotensive effect, a better adherence, and fewer side effects.

[Study on the predictors for superimposed preeclampsia in patients with IgA nephropathy].

OBJECTIVE: Pregnancy in chronic kidney disease (CKD) patients is often associated with hypertension and/or the worsening of renal function and neonatal death. The present study explored the clinical characteristics of predictive factors for hypertension in biopsy-proven IgA nephropathy patients with superimposed preeclampsia (SPE). PATIENTS AND METHODS: The subjects were 34 Japanese women with IgA nephropathy whose renal specimen for histological tests was obtained before pregnancy. We retrospectively investigated the relevant clinical factors to explain a rise in blood pressure (BP). The histological findings were evaluated with respect to the quantitative measurements of both global glomerulosclerosis and interstitial damage. RESULTS: Renal biopsies before pregnancies showed that the global glomerular sclerosing index and interstitial damage in the SPE group were significantly higher than in the normal group. The prevalence of SPE was 38.2 % (normal pregnancy 21, SPE 13 cases). The neonatal death rate was 3.0 % (1/34)overall. Just before conception, systolic blood pressure (SBP), serum creatinine (Cr)and blood urea nitrogen (BUN) concentration in the SPE were significantly higher than in normal pregnancies. In contrast, CCr and eGFR were lower in the SPE group than in the normal group. At delivery, serum Cr, BUN and uric acid (UA) concentration in the SPE group were significantly higher than in the normal group. In contrast, CCr and eGFR were lower in the SPE than in the normal group. At delivery, correlation analysis revealed a significant correlation between SBP or diastolic BP (DBP) and the histological severity, between SBP or DBP and daily protein excretion, and between SBP or DBP and serum Cr concentration. With respect to the birth weight of newborns, there was a significant negative correlation between the birth weight and the global glomerular sclerosing rate, and between the birth weight and serum Cr concentration or BUN. A stepwise multiple regression analysis showed that predictive factors for a rise in SBP during pregnancy were the degree of interstitial damage and daily urinary protein excretion. These results suggest that renal function, the magnitude of urinary protein excretion, serum Cr, BUN, UA concentrations, and the severity of histological abnormalities are all associated with SPE occurrence. The predictors of a rise in BP were interstitial damage and urinary protein excretion at pregnancy. In addition, Receiver Operating Characteristic (ROC) analysis showed that both glomerular sclerosis and interstitial damage could be potential predictors for SPE. CONCLUSION: Histological severity in renal biopsy, urinary protein excretion and renal function are associated with SPE in patients with IgA nephropathy. Among these associations, the histological findings and urinary protein excretion may serve as useful predictors for a rise in BP.

Successful effect of triple blockade of renin-angiotensin-aldosterone system on massive proteinuria in a patient with chronic kidney disease.

A patient with chronic kidney disease (CKD) due to membranous nephropathy with daily urinary protein excretion exceeding 5 g did not respond well to dual therapy with an angiotensin converting enzyme inhibitor (ACE-I) and angiotensin II receptor blocker (ARB). Addition of the mineralocorticoid receptor blocker (MRB), spironolactone, led to moderate reduction in daily urinary protein excretion. However, spironolactone had to be inevitably discontinued due to gynecomastia. Replacement of spironolactone with the selective MRB, eplerenone, added to the preceding treatment with ACE-I and ARB, resulted in remarkable reduction of daily urinary protein excretion to less than 0.2 g. This case suggests that triple blockade of renin-angiotensin-aldosterone (RAA) system with ACE-I, ARB, and MRB could be useful for CKD patients with massive proteinuria.