Reduction In Urinary Protein Excretion Research Articles

The Effect of the Extra Virgin Olive Oil Minor Phenolic Compound 3',4'-Dihydroxyphenylglycol in Experimental Diabetic Kidney Disease.

The aim of this study was to analyze the possible nephroprotective effect of 3',4'-dihydroxyphenylglycol (DHPG), a polyphenolic compound of extra virgin olive oil (EVOO), on renal lesions in an experimental model of type 1 diabetes. Rats were distributed as follows: healthy normoglycemic rats (NDR), diabetic rats treated with saline (DR), and DR treated with 0.5 mg/kg/day or 1 mg/kg/day of DHPG. DR showed a significantly higher serum and renal oxidative and nitrosative stress profile than NDR, as well as reduced prostacyclin production and renal damage (defined as urinary protein excretion, reduced creatinine clearance, increased glomerular volume, and increased glomerulosclerosis index). DHPG reduced the oxidative and nitrosative stress and increased prostacyclin production (a 59.2% reduction in DR and 34.7-7.8% reduction in DHPG-treated rats), as well as 38-56% reduction in urinary protein excretion and 22-46% reduction in glomerular morphological parameters (after the treatment with 0.5 or 1 mg/kg/day, respectively). Conclusions: DHPG administration to type 1-like diabetic rats exerts a nephroprotective effect probably due to the sum of its antioxidant (Pearson's coefficient 0.68-0.74), antinitrosative (Pearson's coefficient 0.83), and prostacyclin production regulator (Pearson's coefficient 0.75) effects.

Efficacy and safety of rituximab for primary nephrotic syndrome with acute kidney injury: A two-center prospective cohort study

The purpose of this study was to investigate the efficacy and safety of a low-dose Rituximab (RTX) regimen driven by peripheral blood B lymphocyte count in the treatment of adult patients with nephrotic syndrome (NS) complicated with acute kidney disease (AKI). We conducted a prospective single-arm study to evaluate the effect of B cells–driven RTX regimen. Patients with NS (MCD, FSGS, MN, IgAN) complicated with AKI fulfilling the inclusion criteria were eligible for this study. Patients were followed up at intervals of 2 months. Student's t-test and Chi-squared test were used to analyze normally distributed continuous variables and non-normally distributed continuous variables, respectively. From August 2018 to January 2022, 23 patients met the inclusion criteria and agreed to participate in the study. 3, 9, and 11 patients were AKI stage 1, 2, and 3, respectively. From baseline to the latest follow-up, 20 patients had complete and partial recovery of renal function. Accompanied by depletion of B cells, significant reduction of urinary protein excretion, serum total cholesterol, and the number of relapses were observed during the 12 months after the first RTX infusion as compared with during the 12 months before RTX injection. The number of patients who maintained steroids and immunosuppressive medications also remarkably decreased. This study indicates that the targets-driven treatment of low-dose RTX can achieve a high remission rate and alleviate the loss of kidney function in treating NS with AKI. The long-term efficacy, side effects, and therapeutic economics of RTX are reasonable.

A Prospective Study to Evaluate the Effects of Sodium-Glucose Cotransporter 2 Inhibitors in Type 2 Diabetic Patients with Chronic Kidney Disease

Introduction: Recent studies suggest that sodium-glucose cotransporter 2 inhibitors (SGLT2i) are effective at slowing the progression of kidney disease and lowering the risk of kidney failure in people with kidney disease and type 2 diabetes. There is no such study from India. The present study was performed to evaluate the effects of SGLT2i in Indian patients with diabetes and chronic kidney disease (CKD). Materials and Methods: This prospective study included 86 patients with diabetes and chronic kidney disease and with an estimated creatinine clearance of >30 mL/minute. Forty-one patients received SGLT2i and 45 patients did not receive SGLT2i. Patients were followed up for at least 12 months. Body mass index (BMI), blood pressure, HbA1c, urine protein to creatinine ratio (UPCR), doubling of serum creatinine and rate of decline of the estimated creatinine clearance were compared between the two groups. Results: The two groups were comparable at baseline in terms of age, sex, blood pressure, BMI, HbA1c, and degree of renal impairment. Over 12 months the UPCR decreased by 0.03 in SGLT2i group and increased by 1.1 in non SGLT2i group (P < 0.05). Doubling of serum creatinine occurred in 4.8% of patients in the SGLT2i group as compared to 18% in the control group (P < 0.05). The rate of decline of the estimated creatinine clearance in the SGLT2i group was 4.9 ml/min/year as compared to 9.4 ml/min/year in the non SGLT2i group (P < 0.05). At 12 months the BMI in the SGLT2i group decreased by 1.49 as compared to 0.12 in the non SGLT2i group (P < 0.05). The blood pressure and HbA1c control were similar in both groups during the study period suggesting that the observed effect was due to SGLT2 inhibition itself and not due to blood pressure or blood glucose control. Conclusion: Our study showed that treatment with SGLT2i had significant renoprotective effects, as shown by a reduction in urinary protein excretion, less percentage of patients developing doubling of serum creatinine, and a slower rate of decline in creatinine clearance.

Monitoring anti-PLA2R antibody titres to predict the likelihood of spontaneous remission of membranous nephropathy.

ABSTRACTBackgroundIn anti-phospholipase A2 receptor (PLA2R) membranous nephropathy (MN) there is controversy whether spontaneous remission (SR) can be predicted using a single titre or by assessing the dynamic changes in anti-PLA2R antibody (ab) titres. The study objective was to identify the optimal dynamics of anti-PLA2Rab titres to predict SR in MN. MethodsA total of 127 nephrotic patients with anti-PLA2R-MN were prospectively followed up for 6 months under conservative treatment. Anti-PLA2Rabs and proteinuria were assessed at diagnosis and monthly thereafter. The primary endpoint (PEP) was a reduction of proteinuria ≥50% at 6 months. Logistic models with baseline and evolutive anti-PLA2Rab titres were developed to predict the PEP. ResultsA total of 28 patients (22%) reached the PEP. These patients were more frequently female and had significantly lower baseline proteinuria and anti-PLA2Rab titres. An anti-PLA2R titre ≤97.5 RU/mL at diagnosis had a sensitivity of 71% and a specificity of 81% to predict the PEP. The model including baseline anti-PLA2Rabs and a reduction ≥15% at 3 months predicted the PEP with a sensitivity of 93% and a specificity of 80%, with an area under the curve that was significantly greater than that obtained with relative changes of proteinuria in the same period of time {odds ratio [OR] 0.95 [95% confidence interval (CI) 0.91–0.98 versus OR 0.79 [95% CI 0.70–0.88], respectively; P = 0.0013}. ConclusionsCombining the baseline anti-PLA2Rab titres with their relative changes at 3 months after diagnosis gives the earliest prediction for achieving a reduction of urinary protein excretion ≥50% at 6 months in MN, thereby shortening the observation period currently recommended to make individualized decisions to start immunosuppressive therapy.

Highlights of the December issue.

Highlights of the December issue.

Successful treatment of gamma 1 heavy chain deposition disease with bortezomib and dexamethasone

Heavy chain deposition disease (HCDD) is a rare complication of plasma cell dyscrasias, characterized by nonamyloid tissue deposits of incomplete monoclonal heavy chains in renal tissues. We report the case of a 78-year-old female with HCDD who was successfully treated with bortezomib and dexamethasone (BD); histopathological improvements were confirmed by kidney biopsy after 2 years of chemotherapy. She presented with renal insufficiency, proteinuria, hematuria, hypogammaglobulinemia, and hypocomplementemia. Renal biopsy showed diffuse global nodular glomerulopathy with the deposition of IgG1 and C3 in the glomeruli and on the tubular basement membrane. Kappa and lambda light chains were not detected. Staining for the constant regions of the gamma heavy chain revealed the absence of the CH1 domain. These findings are consistent with those of gamma 1 HCDD. Results of liquid chromatography-tandem mass spectrometric analysis were consistent with the immunohistochemical results. Two years after weekly BD therapy, normalization of the kappa/lambda ratio and reduction of urinary protein excretion were achieved. A follow-up biopsy showed remarkable diminution of nodular lesions of glomeruli and deposits of IgG and C3.

Efficacy and safety of adding mizoribine to standard treatment in patients with immunoglobulin A nephropathy: A randomized controlled trial.

BackgroundMizoribine (MZR) is an immunosuppressive drug used in Japan for treating patients with lupus nephritis and nephrotic syndrome and has been also reportedly effective in patients with immunoglobulin A (IgA) nephropathy. However, to date, few randomized control studies of MZR are performed in patients with IgA nephropathy. Therefore, this prospective, open-label, randomized, controlled trial aimed to investigate the efficacy and safety of adding MZR to standard treatment in these patients, and was conducted between April 1, 2009, and March 31, 2016, as a multicenter study.MethodsPatients were randomly assigned (1:1) to receiving standard treatment plus MZR (MZR group) or standard treatment (control group). MZR was administered orally at a dose of 150 mg once daily for 12 months.ResultsPrimary outcomes were the percentage reduction in urinary protein excretion from baseline and the rate of patients with hematuria disappearance 36 months after study initiation. Secondary outcomes were the rate of patients with proteinuria disappearance, clinical remission rate, absolute changes in estimated glomerular filtration rate from baseline, and the change in daily dose of prednisolone. Forty-two patients were randomly assigned to MZR (n = 21) and control groups (n = 21). Nine patients in MZR group and 15 patients in the control group completed the study. No significant differences were observed between the two groups with respect to primary and secondary outcomes.ConclusionThe addition of MZR to standard treatment has no beneficial effect on reducing urinary protein excretion and hematuria when treating patients with IgA nephropathy.

Effect of Roux-en-Y gastric bypass and diet-induced weight loss on diabetic kidney disease in the Zucker diabetic fatty rat

BackgroundReductions in urinary protein excretion after Roux-en-Y gastric bypass (RYGB) surgery in patients with diabetic kidney disease have been reported in multiple studies. ObjectivesTo determine the weight loss dependence of the effect of RYGB on urinary protein excretion by comparing renal outcomes in Zucker diabetic fatty rats undergoing either gastric bypass surgery or a sham operation with or without weight matching. SettingUniversity laboratories. MethodsZucker diabetic fatty rats underwent surgery at 18 weeks of age. A subgroup of sham operated rats were weight matched to RYGB operated rats by restricting food intake. Urinary protein excretion was assessed at baseline and at postoperative weeks 4 and 12. Renal histology and macrophage-associated inflammation were assessed at postoperative week 12. ResultsProgressive urinary protein excretion was attenuated by both RYGB and diet-induced weight loss, albeit to a lesser extent by the latter. Both weight loss interventions produced equivalent reductions in glomerulomegaly, glomerulosclerosis, and evidence of renal macrophage infiltration. ConclusionWeight loss per se improves renal structure and attenuates renal inflammatory responses in an experimental animal model of diabetic kidney disease. Better glycemic control post-RYGB may in part explain the greater reductions in urinary protein excretion after gastric bypass surgery.

Sulodexide therapy for the treatment of diabetic nephropathy, a meta-analysis and literature review.

Sulodexide is a heterogeneous group of sulfated glycosaminoglycans (GAGs) that is mainly composed of low-molecular-weight heparin. Clinical studies have demonstrated that sulodexide is capable of reducing urinary albumin excretion rates in patients with type 1 and type 2 diabetes, suggesting that sulodexide has renal protection. However, this efficacy remains inconclusive. In this article, we used meta-analysis to summarize the clinical results of all prospective clinical studies in order to determine the clinical efficacy and safety of sulodexide in diabetic patients with nephropathy. Overall, sulodexide therapy was associated with a significant reduction in urinary protein excretion. In the sulodexide group, 220 (17.7%) achieved at least a 50% decrease in albumin excretion rate compared with only 141 (11.5%) in the placebo. The odds ratio comparing proportions of patients with therapeutic success between the sulodexide and placebo groups was 3.28 (95% confidence interval, 1.34–8.06; P=0.01). These data suggest a renoprotective benefit of sulodexide in patients with diabetes and micro- and macroalbuminuria, which will provide important information for clinical use of this drug as a potential modality for diabetic nephropathy, specifically, the prevention of end-stage renal disease that is often caused by diabetes.

Immunosuppressive agents versus steroids in the treatment of IgA nephropathy-induced proteinuria: A meta-analysis.

Immunoglobulin A nephropathy (IgAN) is one of the most common types of primary glomerular disease. Immunosuppressive treatment for patients with IgAN remains controversial. The present meta-analysis aimed to assess the efficacy and safety of various immunosuppressive agents compared with steroids in patients with IgAN and moderate to severe proteinuria. PubMed, EMBASE, Cochrane Library, Chinese National Knowledge Infrastructure, Wanfang, Weipu, Chinese Biomedical Literature Database and Qinghuatongfang were searched for relevant randomized controlled trials (RCTs) published between 1990 and September 2013. All eligible studies (biopsy proven IgA nephropathy, use of immunosuppressive agents) measured urinary protein excretion and proteinuria remission. Data were analyzed with the random effects model using Review Manager. A total of 29 RCTs were included, involving 1,466 patients. Compared with steroids, immunosuppressive agents, including azathioprine (AZA) [complete response (CR)/partial response (PR); relative risk (RR), 3.43; 95% confidence interval (CI) 1.92–6.12; P<0.0001], mycophenolate mofetil (MMF) (CR/PR; RR, 2.19; 95% CI, 1.25–3.85; P=0.006) and leflunomide (LET) (CR/PR; RR, 2.64; 95% CI, 1.80–3.86; P<0.00001) resulted in increased partial or complete proteinuria remission. Cyclophosphamide (CTX) resulted in a higher reduction of urinary protein excretion than steroids (SMD, 0.91; 95% CI, 0.41–1.41; P=0.0004)). Compared to CTX, LET showed higher effectiveness (CR/PR; RR, 2.01; 95% CI, 1.08–3.75; P=0.03) with a lower incidence of adverse events. The present meta-analysis, which is based on IgAN patients, suggested that AZA, MMF, LET and CTX are effective in reducing proteinuria levels, with acceptable side effects. Therefore, immunosuppressive agents may be considered promising therapeutic agents for the treatment of IgAN and should be investigated further in large sample size, high-quality studies.

Multicentre randomized controlled trial of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker withdrawal in advanced renal disease: the STOP-ACEi trial.

BackgroundBlood pressure (BP) control and reduction of urinary protein excretion using agents that block the renin–angiotensin aldosterone system are the mainstay of therapy for chronic kidney disease (CKD). Research has confirmed the benefits in mild CKD, but data on angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) use in advanced CKD are lacking. In the STOP-ACEi trial, we aim to confirm preliminary findings which suggest that withdrawal of ACEi/ARB treatment can stabilize or even improve renal function in patients with advanced progressive CKD.MethodsThe STOP-ACEi trial (trial registration: current controlled trials, ISRCTN62869767) is an investigator-led multicentre open-label, randomized controlled clinical trial of 410 participants with advanced (Stage 4 or 5) progressive CKD receiving ACEi, ARBs or both. Patients will be randomized in a 1:1 ratio to either discontinue ACEi, ARB or combination of both (experimental arm) or continue ACEi, ARB or combination of both (control arm). Patients will be followed up at 3 monthly intervals for 3 years. The primary outcome measure is eGFR at 3 years. Secondary outcome measures include the number of renal events, participant quality of life and physical functioning, hospitalization rates, BP and laboratory measures, including serum cystatin-C. Safety will be assessed to ensure that withdrawal of these treatments does not cause excess harm or increase mortality or cardiovascular events such as heart failure, myocardial infarction or stroke.ResultsThe rationale and trial design are presented here. The results of this trial will show whether discontinuation of ACEi/ARBs can improve or stabilize renal function in patients with advanced progressive CKD. It will show whether this simple intervention can improve laboratory and clinical outcomes, including progression to end-stage renal disease, without causing an increase in cardiovascular events.

Antiproteinuric effect of angiotensin receptor blockers in normotensive patients with proteinuria: A meta-analysis of randomized controlled trials

The objective of this article is to evaluate the antiproteinuric effect of angiotensin receptor blockers (ARBs) in normotensive patients with proteinuria. We reviewed randomized controlled trials assessing ARBs treatment in patients with normotension and proteinuria. Data concerning the study design, patient characteristics, and outcomes were extracted. Ratio of means was calculated by using the generalized inverse variance method. Eight trials involving 866 patients were included in this study. Compared with a control group, ARBs group was associated with a significant reduction in urinary protein excretion (ratio of means 0.53, 95% CI 0.44-0.64). Subgroup analysis shows that ARBs therapy resulted in a significant decrease in urinary protein excretion in diabetic patients with microalbuminuria or nondiabetic nephropathy with overt proteinuria (ratio of means 0.57, 95% CI 0.47-0.69 and 0.46, 95% CI 0.26-0.83, respectively), in a Western population or an Asian population (ratio of means 0.61, 95% CI 0.54-0.69 and 0.49, 95% CI 0.37-0.64, respectively), and in patients followed up for one to three months or three to 12 months (ratio of means 0.62, 95% CI 0.54-0.70 and 0.49, 95% CI 0.38-0.63, respectively). The data suggest that ARBs may have beneficial effects in preventing the progression of proteinuria in normotensive patients with renal disease.

Educational Paper: Progression in chronic kidney disease and prevention strategies

Chronic kidney disease (CKD) in children is a rare but devastating condition. Once a critical amount of nephron mass has been lost, progression of CKD is irreversible and results in end-stage renal disease (ESRD) and need of renal replacement therapy. The time course of childhood CKD is highly variable. While in children suffering from congenital anomalies of the kidneys and the urinary tract, progression of CKD in general is slow, in children with acquired glomerulopathies, disease progression can be accelerated resulting in ESRD within months. However, irrespective of the underlying kidney disease, hypertension and proteinuria are independent risk factors for progression. Thus, in order to prevent progression, the primary objective of treatment should always aim for efficient control of blood pressure and reduction of urinary protein excretion. Blockade of the renin-angiotensin-aldosterone system preserves kidney function not only by lowering blood pressure, but also by reducing proteinuria and exerting additional anti-proteinuric, anti-fibrotic, and anti-inflammatory effects. Besides, intensified blood pressure control, aiming for a target blood pressure below the 50th percentile, may exert additive renoprotective effects. Additionally, other modifiable risk factors, such as anemia, metabolic acidosis, dyslipidemia, and altered bone-mineral homeostasis may also contribute to CKD progression. In conclusion, beyond strict blood pressure control and reduction of urinary protein excretion, identification and treatment of both, renal disease-related and conventional risk factors are mandatory in children with CKD in order to prevent deterioration of kidney function.

Treatment of idiopathic membranous nephropathy with combination of low-dose tacrolimus and corticosteroids

Evidence regarding the optimal dose of tacrolimus (TAC) in treatment of idiopathic membranous nephropathy (IMN) remains inconclusive. The objective of this study was to evaluate the efficacy and safety of low-dose TAC combined with prednisone for patients with IMN. We conducted a randomized prospective cohort study in IMN patients: 28 patients received oral TAC (target whole blood concentration of 2-4 ng/mL) plus prednisone for 12 months, and 28 patients received prednisone combined with intravenous cyclophosphamide (CYC) (750 mg/m2 body surface) once every 4 weeks for 24 weeks. Of the 56 patients who completed the 12-month treatment, complete remission (CR) occurred in 8 (28.6%) of the CYC group and 18 (64.3%) of the TAC group; partial remission (PR) occurred in 10 (35.7%) of the CYC group and 7 (25.0%) of the TAC group. The probability of remission (either CR or PR) was higher in the TAC group than in the CYC group (p = 0.0439, by log-rank test). Furthermore, a significantly greater improvement in proteinuria and serum albumin levels was observed in the TAC group compared with the CYC group. Patients treated with TAC can often show a rapid increase in their serum albumin levels before any obvious reduction of urinary protein excretion. Side effects were mild and transitory in both groups. The results demonstrated that the combined therapy of low-dose TAC and prednisone is an effective and safe therapeutic method for Chinese adults with IMN. Low-dose TAC accompanied by prednisone is enough to induce remission in the majority of patients with IMN.

The long-term antiproteinuric effect of eplerenone, a selective aldosterone blocker, in patients with non-diabetic chronic kidney disease

There is still insufficient data concerning the clinical effects of eplerenone, a selective aldosterone blocker, in patients with non-diabetic chronic kidney disease (CKD). This study included non-diabetic CKD patients with urinary protein excretion (UPE) of 1.0 g/gCr or more in spite of long-term treatment with renin-angiotensin system (RAS) inhibitors. The clinical effects of eplerenone (25-50 mg/day) were investigated for 12 months. Eplerenone treatment was associated with a 38% reduction in UPE after 12 months. There was only a slight increase in the serum potassium level. The reduction of proteinuria was observed more prominently in patients with modestly impaired renal function than in those with preserved renal function at baseline. The long-term administration of low-dose eplerenone was effective and safe for the treatment of non-diabetic CKD patients who showed persistent proteinuria in spite of therapy with RAS inhibitors.

Anti-Proteinuric Effect of Sulodexide in Immunoglobulin A Nephropathy

PurposeWe conducted a multi-center randomized double-blind study to determine the effects of 6-month therapy with sulodexide on urinary protein excretion in patients with idiopathic Immunoglobulin A (IgA) nephropathy.Materials and MethodsA total of seventy-seven patients participated in the study. They were randomly allocated to one of three groups: sulodexide 75 mg or 150 mg daily or the placebo for 6 months. The primary end point was the achievement, at 6 months, of at least 50% reduction in urine protein/creatinine ratio (UPCR) from the baseline value.ResultsAt 6 months, the primary end point was achieved by 12.5% of the patients assigned to the placebo, 4.0% of the patients assigned to sulodexide 75 mg daily and 21.4% of those assigned to 150 mg (p=0.308). Treatment with sulodexide 150 mg daily for 6 months significantly reduced log UPCR from 6.38±0.77 at baseline to 5.98±0.94 at 6 months (p=0.045), while treatment with sulodexide 75 mg daily and placebo did not.ConclusionA 6-month treatment with sulodexide did not achieve 50% reduction of urinary protein excretion in IgA nephropathy patients, but showed a tendency to increase the time-dependent anti-proteinuric effect. Therefore, long-term clinical trials on a larger scale are warranted to elucidate the hypothesis that sulodexide affords renal protection in IgA nephropathy patients.

Direct renin inhibition: An update

Aliskiren, the first orally effective direct renin inhibitor, is an effective antihypertensive agent with distinctive properties including placebo-like tolerability, pharmacologic effects that persist after drug discontinuation, and a unique mechanism of action. When combined with agents that inhibit the renin-angiotensin-aldosterone system (RAAS), such as angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, or beta-blockers, additional blood pressure reduction reflects more complete RAAS blockade. Concern that marked elevation in plasma renin concentration following aliskiren administration might lead to RAAS-induced paradoxical blood pressure increases appears unfounded, based upon analyses of patients participating in clinical trials. Studies in animals and humans indicate that aliskiren accumulates in renal tissue, blocks the intrarenal RAAS, and interferes with deleterious cellular effects of angiotensin II by mechanisms that may include enzymatic blockade of renin and prorenin at the site of the (pro)renin receptor. In patients with diabetic nephropathy, adding aliskiren to losartan resulted in an additional 20% reduction in urinary protein excretion. In patients with heart failure, aliskiren reduced brain natriuretic peptide levels when added to other RAAS inhibitors, suggesting an additional hemodynamic effect. The ASPIRE HIGHER clinical trials program is assessing whether the promising pharmacologic properties of aliskiren translate into long-term clinical benefits.

Benefits of dietary sodium restriction in the management of chronic kidney disease

To evaluate the role of restricting dietary sodium intake in chronic kidney disease (CKD) and its complications. A consistent line of evidence shows that high dietary sodium intake is a determinant of therapy resistance to blockade of the renin-angiotensin-aldosterone system (RAAS). Addition of sodium restriction to RAAS blockade or to RAAS blockade combined with a diuretic permits a further reduction in urinary protein excretion of approximately 30%, which could be expected to reduce long-term renal risk by 25%. High sodium intake increases blood pressure and proteinuria, induces glomerular hyperfiltration and blunts the response to RAAS blockade. Although recommended in international guidelines, sodium restriction is not a spearhead in treating renal patients. Sodium status is only rarely mentioned in recent large intervention studies in CKD. Sodium intake in CKD is similar to that in the general population. Reduction of sodium intake to the target of 50-85 mmol/24 h in patients with CKD reduces blood pressure and proteinuria, the latter by approximately 30%, and should be actively pursued to improve outcome in CKD.

Proteinuria-Reducing Effects of Tonsillectomy Alone in IgA Nephropathy Recurring After Kidney Transplantation

Few studies have been conducted to determine the efficacy of tonsillectomy in suppressing IgA nephropathy recurring after the kidney transplantation. Of the 405 kidney recipients who received allograft transplants at our institution between 1998 and 2005, 63 (63 of 405, 16%) were diagnosed as having recurrence of IgA nephropathy in the kidney graft. Among the 63 patients, our subjects in this study were 28 patients who were confirmed to have recurrence of IgA nephropathy by histopathological examination, and who had persistent urinary protein excretion levels of more than 300 mg/day despite medical treatments. Sixteen patients (group 1) underwent tonsillectomy alone, whereas the remaining 12 patients (group 2) did not receive tonsillectomy. The degree of proteinuria, kidney graft function, and blood pressure were analyzed retrospectively in the two patient groups. The urinary protein excretion decreased dramatically after the tonsillectomy in all of the 16 patients of group 1 (880+/-630 mg/day to 280+/-220 mg/day, P<0.01) but none of group 2. The reduction in urinary protein excretion after tonsillectomy was especially marked in the patients with mild mesangial changes, such as minor glomerular abnormalities, when compared with that in patients with severe mesangial changes, such as diffuse proliferative glomerular abnormalities (mean percent decrease in the urinary protein excretion rate at 12 months after tonsillectomy; 31% minor glomerular abnormalities vs. 62% diffuse proliferative glomerular abnormalities, P<0.01). These results suggest that in patients receiving oral immunosuppressive therapy for recurrence of IgA nephropathy after the kidney transplantation, reduction of the urinary protein excretion can be expected with tonsillectomy alone, without accompanying pulsed steroid therapy.

Camostat mesilate inhibits prostasin activity and reduces blood pressure and renal injury in salt-sensitive hypertension

Prostasin, a glycosylphosphatidylinositol-anchored serine protease, regulates epithelial sodium channel (ENaC) activity. Sodium reabsorption through ENaC in distal nephron segments is a rate-limiting step in transepithelial sodium transport. Recently, proteolytic cleavage of ENaC subunits by prostasin has been shown to activate ENaC. Therefore, we hypothesized that serine protease inhibitors could inhibit ENaC activity in the kidney, leading to a decrease in blood pressure. We investigated the effects of camostat mesilate, a synthetic serine protease inhibitor, and FOY-251, an active metabolite of camostat mesilate, on sodium transport in the mouse cortical collecting duct cell line (M-1 cells) and on blood pressure in Dahl salt-sensitive rats. Treatment with camostat mesilate or FOY-251 decreased equivalent current (Ieq) in M-1 cells in a dose-dependent manner and inhibited the protease activity of prostasin in vitro. Silencing of the prostasin gene also reduced equivalent current in M-1 cells. The expression level of prostasin protein was not changed by application of camostat mesilate or FOY-251 to M-1 cells. Oral administration of camostat mesilate to Dahl salt-sensitive rats fed a high-salt diet resulted in a significant decrease in blood pressure with elevation of the urinary Na/K ratio, decrease in serum creatinine, reduction in urinary protein excretion, and improvement of renal injury markers such as collagen 1, collagen 3, transforming growth factor-beta1, and nephrin. These findings suggest that camostat mesilate can decrease ENaC activity in M-1 cells probably through the inhibition of prostasin activity, and that camostat mesilate can have beneficial effects on both hypertension and kidney injury in Dahl salt-sensitive rats. Camostat mesilate might represent a new class of antihypertensive drugs with renoprotective effects in patients with salt-sensitive hypertension.