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1.  Management of Membranous Nephropathy in Asia 
Kidney Diseases  2015;1(2):119-125.
Background
Membranous nephropathy (MN) is the most common cause of nephrotic syndrome (NS) in adults, accounting for about 20.0% of all NS cases. With an increasing prevalence, especially in the elderly, it has received great attention in Asia.
Summary
Recently, the prevalence of idiopathic MN (IMN) has significantly increased among the elderly people in Asia and other places in the world. Although the exact mechanism of IMN remains unveiled, the identification of new antigens such as PLA2R and THSD7A has greatly enhanced our understanding of its pathogenesis. However, consensus has not yet been reached for the treatment of IMN in Asia. For example, there are many choices of immunosuppressive agents, including corticosteroid monotherapy, corticosteroids combined with cytotoxic agents [such as alkylating agents, calcineurin inhibitors or mycophenolate mofetil (MMF)] or traditional Chinese medicine (triptolide, Shenqi and other Chinese herbal soups). Patients with IMN in Asia often have a favorable prognosis, and progression to end-stage renal disease is relatively uncommon compared to other populations.
Key Messages
The prevalence of MN has significantly increased in the last years. The treatment strategies for IMN have not reached consensus in Asia. Traditional Chinese medicine is generally preferred by the Chinese, and compelling results have been reported recently.
Facts from East and West
(1) The prevalence of IMN is increasing worldwide, particularly in elderly patients, and has been reported in 20.0–36.8% of adult-onset NS cases. The presence of anti-PLA2R antibodies in serum or PLA2R on renal biopsy is the most predictive feature for the diagnosis of IMN and is used in both the East and West; however, appropriate screening to rule out secondary causes should still be performed. (2) Several observational (nonrandomized) Asian studies indicate a good response to corticosteroids alone in IMN patients, although no randomized controlled trials have been done in Asian membranous patients at high risk of progression. Corticosteroid monotherapy has failed in randomized controlled trial studies in Western countries and is therefore not recommended. (3) Cyclophosphamide is the most commonly prescribed alkylating agent in Europe and China. Also, chlorambucil is still used in some Western countries, particularly in Europe. In North America, calcineurin inhibitors are the more common first-line treatment. (4) Cyclosporine is predominantly used as monotherapy in North America, although KDIGO (Kidney Disease: Improving Global Outcomes) and Japanese guidelines still recommend a combination with low-dose corticosteroids. Clinical studies both in Asia and Europe showed no or little effects of monotherapy with MMF compared to standard therapies. (5) There are encouraging data from nonrandomized Western studies for the use of rituximab and a few small studies using adrenocorticotropic hormone. Clinical trials are ongoing in North America to confirm these observations. These drugs are rarely used in Asia. (6) A Chinese study reported that 36% of IMN patients suffered from venous thromboembolism versus 7.3% in a North American study. Prophylactic anticoagulation therapy is usually added to IMN patients with a low risk of bleeding in both Eastern and Western countries. (7) The Chinese traditional medicine herb triptolide, which might have podocyte-protective properties, is used in China to treat IMN. An open-label, multicenter, randomized controlled trial showed that Shenqi, a mixture of 13 herbs, was superior to corticosteroids plus cyclophosphamide therapy to restore epidermal growth factor receptor in IMN patients, although proteinuria improvement was equal in the two groups. Importantly, Shenqi treatment induced no severe adverse events while standard therapy did.
doi:10.1159/000437288
PMCID: PMC4934810  PMID: 27536672
Membranous nephropathy; Management; Prognosis; Traditional Chinese medicine
2.  Management of Membranous Nephropathy in Western Countries 
Kidney Diseases  2015;1(2):126-137.
Background
Idiopathic membranous nephropathy (IMN) is a common cause of nephrotic syndrome (NS) in adults in Western countries. In 2012, the KDIGO (Kidney Disease: Improving Global Outcomes) working group published guidelines for the management of glomerulonephritis, thus providing a template for the treatment of this condition. While being aware of the impact of the clinicians' acumen and that patients may choose a different therapeutic option due to the risks of specific drugs and also of the evolving guidelines, this review details our approach to the management of patients with IMN in a Western center (Toronto).
Summary
Based on studies published in Europe and North America, we included recent advances in the diagnosis and management of patients with membranous nephropathy similar to our practice population. We highlight the importance of establishing the idiopathic nature of this condition before initiating immunosuppressive therapy, which should include the screening for secondary causes, especially malignancy in the elderly population. The expected outcomes with and without treatment for patients with different risks of progression will be discussed to help guide clinicians in choosing the appropriate course of treatment. The role of conservative therapy as well as of established immunosuppressive treatment, such as the combination of cyclophosphamide and prednisone, and calcineurin inhibitors (CNIs), as well as of newer agents such as rituximab will be reviewed.
Key Messages
Appropriate assessment is required to exclude secondary conditions causing membranous glomerulonephritis. The role of antibodies to phospholipase A2 receptor (anti-PLA2R) in establishing the primary disease is growing, though more data are required. The increase in therapeutic options supports treatment individualization, taking into account the availability, benefits and risks, as well as patient preference.
Facts from East and West
(1) The prevalence of IMN is increasing worldwide, particularly in elderly patients, and has been reported in 20.0–36.8% of adult-onset NS cases. The presence of anti-PLA2R antibodies in serum or PLA2R on renal biopsy is the most predictive feature for the diagnosis of IMN and is used in both the East and West; however, appropriate screening to rule out secondary causes should still be performed. (2) Several observational (nonrandomized) Asian studies indicate a good response to corticosteroids alone in IMN patients, although no randomized controlled trials (RCTs) have been done in Asian membranous patients at high risk of progression. Corticosteroid monotherapy has failed in randomized controlled studies in Western countries and is therefore not recommended. (3) Cyclophosphamide is the most commonly prescribed alkylating agent in Europe and China. Also, chlorambucil is still used in some Western countries, particularly in Europe. In North America, CNIs are the more common first-line treatment. (4) Cyclosporine is predominantly used as monotherapy in North America, although KDIGO and Japanese guidelines still recommend a combination with low-dose corticosteroids. Clinical studies both in Asia and Europe showed no or little effects of monotherapy with mycophenolate mofetil compared to standard therapies. (5) There are encouraging data from nonrandomized Western studies for the use of rituximab and a few small studies using adrenocorticotropic hormone. Clinical trials are ongoing in North America to confirm these observations. These drugs are rarely used in Asia. (6) A Chinese study reported that 36% of IMN patients suffered from venous thromboembolism versus 7.3% in a North American study. Prophylactic anticoagulation therapy is usually added to IMN patients with a low risk of bleeding in both Eastern and Western countries. (7) The Chinese traditional medicine herb triptolide, which might have podocyte-protective properties, is used in China to treat IMN. An open-label, multicenter RCT showed that Shenqi, a mixture of 13 herbs, was superior to corticosteroids plus cyclophosphamide therapy to restore epidermal growth factor receptor in IMN patients, although proteinuria improvement was equal in the two groups. Importantly, Shenqi treatment induced no severe adverse events while standard therapy did.
doi:10.1159/000437287
PMCID: PMC4934807  PMID: 27536673
Nephrotic syndrome; Membranous nephropathy; Glomerulonephritis
3.  Circulating TNF Receptors Are Significant Prognostic Biomarkers for Idiopathic Membranous Nephropathy 
PLoS ONE  2014;9(8):e104354.
Idiopathic membranous nephropathy (iMN) is a common cause of nephrotic syndrome in adults. A biomarker to accurately indicate the severity of iMN and predict long-term prognosis is insufficient. Here, we evaluated the clinical significance of circulating tumor necrosis factor receptors (cTNFRs) as prognostic biomarkers of iMN with nephrotic syndrome. A total of 113 patients with biopsy-proven iMN and 43 healthy volunteers were enrolled in this study. Ninety patients with iMN had nephrotic range proteinuria. Levels of cTNFRs were measured by using serum samples collected at the time of initial diagnosis. Levels of cTNFRs were higher in the patients with nephrotic syndrome than in those with subnephrotic range proteinuria or in the healthy volunteers (P for trend <0.001). Estimated glomerular filtration rate and proteinuria tended to worsen as the cTNFRs levels increased. Having a cTNFR1 level within the highest tertile was a significant risk factor for renal progression after adjustment, in comparison with the other tertiles (hazard ratio [HR], 3.39; 95% confidence interval [95% CI], 1.48–7.78; P = 0.004). The cTNFR2 level within the highest tertile also significantly increased the risk of renal progression (HR, 3.29; 95% CI, 1.43–7.54; P = 0.005). Renal tubular TNFRs expression was associated with cTNFRs level. However, the cTNFRs levels were not associated with autoantibody against phospholipase A2 receptor reactivity/levels or treatment response. This study demonstrated that cTNFRs levels at the time of initial diagnosis could predict renal progression in patients with iMN.
doi:10.1371/journal.pone.0104354
PMCID: PMC4123977  PMID: 25098821
4.  Analysis of the prognostic risk factors of idiopathic membranous nephropathy using a new surrogate end-point 
Biomedical Reports  2015;4(2):147-152.
Idiopathic membranous nephropathy (IMN) is one of the most common causes of nephrotic syndrome (NS) in adults. The latest study of the chronic kidney disease-prognosis consortium showed that a 30% decrease in the estimated glomerular filtration rate (eGFR) within 2 years could cover more patients and showed a better correlation with end-stage renal disease (ESRD), as compared with serum creatinine (SCr). The aim of the present study was to analyze prognostic factors of ESRD using a 30% decrease in eGFR within 2 years as the end-point. The medical records of patients who were diagnosed as having IMN by clinical pathology between February 2011 and August 2012 and had been followed up for ≥24 months were analyzed retrospectively. A 30% decrease in eGFR or the occurrence of ESRD were the end-points. Factors affecting the prognosis were analyzed by the χ2 test and multivariate logistic regression analysis, and the cumulative risk of risk factors was analyzed by Kaplan-Meier curve. A total of 73 patients with IMN were confirmed by clinical pathology. Blood pressure, tubulointerstitial injury area (TIA), glomerular sclerosis ratio, SCr, blood urea nitrogen, cystatin C, serum albumin and 24-h urine protein. In total, 28 patients (38.4%) reached the observation end-point. Multivariate logistic regression analysis showed that only age ≥60 years, serum albumin <25 g/l and TIA >25% were independent risk factors for predicting the occurrence of end-point events in the two groups (P<0.05), which increased the risk of the occurrence of end-point events in IMN patients by 3.471-, 3.195- and 6.724-fold, respectively. Kaplan-Meier curve showed that the occurrence of end-point events within 2 years was significantly higher in IMN patients whose age was ≥60 years, serum albumin <25 g/l and TIA >25% (log-rank P=0.004, P=0.024 and P=0.001). The results of the present study revealed that age ≥60 years, low serum albumin concentrations and severe tubulointerstitial injury are independent risk factors for the occurrence of ESRD in IMN patients.
doi:10.3892/br.2015.555
PMCID: PMC4734144  PMID: 26893829
idiopathic membranous glomerulonephritis; glomerular filtration rate; outcome; risk factors; Chinese population
5.  Infusion of autologous bone marrow mononuclear cells leads to transient reduction in proteinuria in treatment refractory patients with Idiopathic membranous nephropathy 
BMC Nephrology  2013;14:262.
Background
The current treatment options for idiopathic membranous nephropathy (IMN) carry significant toxicity. In this prospective, observational pilot study, we used single time infusion of bone marrow derived autologous mononuclear cells (MNCs) in adult patients with treatment refractory IMN.
Methods
Twelve patients of biopsy proven IMN who had failed a cyclical 6-month regimen of steroid and cyclophosphamide were enrolled in the study. Bone-marrow was harvested from the iliac crest and underwent processing to isolate MNCs. Cells were counted and subjected to viability testing before being infused through a peripheral vein on the same day. After the infusion, subjects were followed up monthly for the next six months. Supportive treatment including angiotensin antagonists and statins was continued throughout the study period.
Result
The proteinuria, serum albumin and creatinine values at entry were 2.97 ± 0.6 gm/1.73 m2/d, 2.27 ± 1.1 gm/l and 0.9 ± 0.8 mg/dl respectively. There was a reduction in proteinuria (p < 0.0001), and increase in serum albumin (p = 0.001) at 1 month, with 64% of the subjects showing >50% reduction in proteinuria. However, the response was ill sustained. At 6 months, only 2 patients had >50% reduction. Serum creatinine remained stable throughout the study period. No infusion related side effects were noted.
Conclusion
Autologous mononuclear cell infusion leads to transitory reduction in proteinuria and improvement in serum albumin in treatment refractory IMN. This effect, however, is transient. Whether this can be overcome by repeated infusion of cultured mesenchymal cells needs to be investigated.
doi:10.1186/1471-2369-14-262
PMCID: PMC4219434  PMID: 24289828
6.  Anti-phospholipase A2 receptor antibody in idiopathic membranous nephropathy: A report from Iranian population 
Journal of Nephropathology  2013;2(4):241-248.
Background: Idiopathic Membranous Nephropathy (iMN) is the most common cause of nephrotic syndrome in adults. Approximately one third of patients with iMN progress to end-stage renal disease. Anti-phospholipase A2-receptor (anti-PLA2R) antibodies are present in patients with iMN and appear to play a role in the pathogenesis of iMN. Objectives: In this study, we explored the prevalence of anti-PLA2R antibodies in a cohort of patients with iMN in Iran. We also sought to determine circulating levels of anti-secretory PLA2 (anti-sPLA2) antibodies in those with anti-PLA2R antibodies.
Patients and Methods: Using an indirect immunofluorescence assay, we measured anti-PLA2R antibodies in a group of patients with iMN in Iran. The serum levels of anti-sPLA2 antibodies were also measured in those with positive results for anti-PLA2R antibodies.
Results: We studied 23 patients with iMN (M/F 12/11, 34±9.8 year), two patients with secondary MN and five patients  with the nephrotic syndrome of other causes.Anti-PLA2R antibodies were detected in 17/23 (74%) of patients with iMN, but not in those with secondary MN or other forms of primary glomerular diseases. We found no correlation between anti-PLA2R antibody titer and the degree of proteinuria. We found high titers of anti-sPLA2 antibodies in a subset of patients with high levels of anti-PLA2R antibodies.
Conclusions: Anti-PLA2R antibodies are specific for iMN. Proteinuria may also reflect glomerular structural damage rather than immunological activity of the disease. The preliminary idea of any presumptive role of anti-sPLA2antibodies in iMN needs further  investigation.
doi:10.12860/JNP.2013.38
PMCID: PMC3891130  PMID: 24475456
Idiopathic membranous nephropathy; Anti-phospholipase A2-receptor antibodies; Anti-phospholipase A2 antibodies nephrotic syndrom; End-stage renal disease
7.  Idiopathic membranous nephropathy in pediatric patients: presentation, response to therapy, and long-term outcome 
BMC Nephrology  2007;8:11.
Background
Idiopathic membranous nephropathy (IMN) is one of the most common causes of primary nephrotic syndrome in adults. However, it is a relatively rare entity in the pediatric population and there is a paucity of data about the incidence, prognosis, and optimal treatment of IMN in children and adolescents. We conducted this study to evaluate pediatric patients with IMN in order to clarify the presentation, response to therapy, and clinical outcome.
Methods
A retrospective chart review was performed on patients identified with biopsy-proven IMN between 1988–2005. Patients with systemic lupus erythematosus or hepatitis-related lesions were excluded. The following data were tabulated: age, gender, ethnicity, presenting clinical and laboratory findings, proteinuria in a first morning urine specimen, estimated glomerular filtration rate (GFRe), histopathology, type and duration of treatment, and clinical status at final evaluation.
Results
13 cases of IMN were identified out of 460 renal biopsies performed for evaluation of primary kidney disease during the study interval. Mean age was 9.6 ± 4.6, gender 6 M:7 F, ethnicity 8 W:2 B:3 H. At the initial visit hematuria was present in 9 patients, edema in 5, nephrotic-range proteinuria in 5, and hypertension in 3. Mean urinary protein:creatinine ratio 3.3 ± 2.5 and all patients had a normal GFRe. Classic glomerular findings of IMN were seen in all renal specimens, with concomitant interstitial changes in 2 cases. Treatment included an angiotensin converting enzyme inhibitor or angiotensin receptor blocker in 11 cases. Most patients were also given immunosuppressive medications – prednisone in 10, a calcineurin inhibitor in 5, and mycophenolate mofetil or azathioprine in 3 patients. At the last follow-up, 42 ± 35 months after the diagnostic biopsy, 7 children were hypertensive and the urine protein:creatinine ratio was 2.3 ± 3.1. The mean GFRe was 127 ± 57 mL/min/m2. Three patients had Chronic Kidney Disease Stage 3, all of whom were also hypertensive.
Conclusion
IMN is a rare but serious glomerulopathy in pediatrics. We estimate that it accounts for approximately 3% of renal biopsies. Long-term prognosis is guarded because approximately 50% of patients may have evidence of progressive kidney disease.
doi:10.1186/1471-2369-8-11
PMCID: PMC1959515  PMID: 17683621
8.  Evaluating tacrolimus treatment in idiopathic membranous nephropathy in a cohort of 408 patients 
BMC Nephrology  2017;18:2.
Background
The KDIGO Clinical Practice Guidelines for Glomerulonephritis recommended tacrolimus as an alternative regimen for the initial therapy for Idiopathic membranous nephropathy (IMN), however, large observational studies evaluating tacrolimus treatment in IMN remains rare.
Methods
A total of 408 consecutive IMN patients with nephrotic syndrome who were treated with tacrolimus in Jinling Hospital were included. The effectiveness and safety of tacrolimus treatment in IMN were analyzed in this study.
Results
The cumulative partial or complete remission after tacrolimus therapy were 50%, 63% and 67% at 6, 12 and 24 months, respectively, and the cumulative complete remission rates were 4%, 13% and 23%, respectively. Multivariate logistic analysis showed that higher tacrolimus exposure during induction treatment, female gender, higher eGFR and no history of previous immunosuppressive therapy were independently associated with higher probability of remission. A relapse occurred in 101 of the 271 (37.3%) patients with partial or complete remission, and 18 of the 95 (18.9%) patients with complete remission. Tapering duration of tacrolimus and complete remission versus partial remission status were independent factors associated with risk of relapse. A decline in eGFR was the most frequent adverse event during tacrolimus treatment. During tacrolimus treatment, a ≥40% decrease in eGFR was observed in 43 (10.5%) patients.
Conclusions
Low dose tacrolimus is effective for IMN, with a total remission rate of 66% whereas with a rather high rate of relapse. However, the safety of tacrolimus treatment needs to be further validated in large randomized clinical trials.
doi:10.1186/s12882-016-0427-z
PMCID: PMC5216560  PMID: 28056860
Membranous nephropathy; Immune suppression; Clinical nephrology
9.  Comparison of tripterygium wilfordii multiglycosides and tacrolimus in the treatment of idiopathic membranous nephropathy: a prospective cohort study 
BMC Nephrology  2015;16:200.
Background
Idiopathic membranous nephropathy (IMN) is a major cause of nephrotic syndrome among adults. Considering the natural course of IMN, when to treat and with which immunosuppressive treatment need to be carefully considered in such patients. A combination of tripterygium wilfordii multiglycosides (TWG) and prednisone may be an effective option for treating patients with IMN.
Methods
In this prospective cohort study, we enrolled patients with biopsy-proven IMN at our kidney centre. One cohort received TWG combined with prednisone, whereas another cohort received tacrolimus (TAC) combined with prednisone, for 36 weeks. The primary outcome was the remission rate, whereas the secondary outcomes included the time to remission, relapse rate, changes in serum albumin levels and daily urinary protein levels, estimated glomerular filtration rate, and adverse events.
Results
A total of 53 patients with IMN met the criteria for enrolment, and all patients completed the therapy. At the end of the 36-week therapy, remission (either partial remission [PR] or complete remission [CR]) was observed in 20 patients (86.9 %) receiving TWG and in 27 patients (90.0 %) receiving TAC (p > 0.05), whereas CR was noted in 12 patients (52.2 %) receiving TWG and 14 patients (46.7 %) receiving TAC (p > 0.05). The probability of remission was similar for both the TWG and TAC groups (p > 0.05, by log-bank test). The mean time for achieving remission was 11.8 ± 12.5 weeks in the TWG group and 8.5 ± 9.1 weeks in the TAC group (p > 0.05).
Conclusions
The combination of TWG and predisone is an effective and safe therapy for IMN.
doi:10.1186/s12882-015-0199-x
PMCID: PMC4669631  PMID: 26637482
Idiopathic membranous nephropathy; Tripterygium wilfordii Hook F; Tripterygium wilfordii multiglycosides; Tacrolimus
10.  Treatment of nephrotic syndrome with adrenocorticotropic hormone (ACTH) gel 
Purpose:
A synthetic adrenocorticotropin (ACTH) analog has shown efficacy in Europe as primary and secondary therapy for nephrotic syndrome, but there is no published experience using the natural, highly purified ACTH gel formulation, available in the United States, for nephrotic syndrome. We therefore investigated the use of ACTH gel for nephrotic syndrome in the United States.
Patients and methods:
Twenty-one patients with nephrotic syndrome treated with ACTH gel outside of research settings in the United States, with initiation of therapy by December 31, 2009, allowing a minimum 6 months follow-up. We defined complete remission as stable renal function with proteinuria falling to <500 mg/day, and partial remission as stable renal function with >50% reduction in proteinuria from 500 to 3500 mg/day.
Results:
Twenty-one patients with nephrotic syndrome were treated: 11 with idiopathic membranous nephropathy (iMN), 4 with membranoproliferative glomerulonephritis (MPGN), 1 with focal segmental glomerulosclerosis (FSGS), 1 with minimal change disease (MCD), 1 with immunoglobulin A (IgA) nephropathy, 1 with class V systemic lupus erythematosus (SLE) glomerulonephritis, 1 with monoclonal diffuse proliferative glomerulonephritis, and 1 with unbiopsied nephrotic syndrome. ACTH was used as primary therapy for 3 patients; the remaining patients had previously failed a mean 2.3 immunosuppressive regimens. Eleven patients achieved a complete or partial remission, with 4 (19%) in complete remission. Of the 11 patients who achieved remission, 9 had iMN, 1 had FSGS, and 1 had IgA nephropathy. Of the 11 patients with iMN, 3 (27%) achieved complete remission and 6 (55%) achieved partial remission despite having previously failed a mean 2.4 therapies. Five patients reported steroid-like adverse effects, but there were no severe infections. The limitations were retrospective data analysis with short-term follow-up.
Conclusion:
ACTH gel may be a viable treatment option for resistant nephrotic syndrome due to membranous nephropathy. Short-term data suggest that remission rates may approach 80%.
doi:10.2147/DDDT.S17521
PMCID: PMC3063118  PMID: 21448451
nephrotic syndrome; membranous nephropathy; chronic kidney disease
11.  Acthar gel in the treatment of nephrotic syndrome: a multicenter retrospective case series 
BMC Nephrology  2016;17:37.
Background
Current first-line anti-proteinuric treatments for nephrotic syndrome (NS) do not produce an effective response in all patients and are not tolerated by some patients. Additional effective and tolerable treatment options in NS are strongly needed. This retrospective case series is the largest to date to examine Acthar gel (adrenocorticotropic hormone, ACTH) in patients with varied-etiology NS.
Methods
This multicenter retrospective case series included adult patients with NS (N = 44) treated with Acthar gel at 6 clinical practices. NS etiologies included idiopathic focal segmental glomerulosclerosis (FSGS, 15), idiopathic membranous nephropathy (iMN, 11), IgA nephropathy (IgAN, 5), diabetic nephropathy (DN, 4), systemic lupus erythematosus class V membranous lupus nephritis (MLN, 2), minimal change disease (MCD, 2), membranoproliferative glomerulonephritis (MPGN, 1), fibrillary glomerulonephritis (FGN, 1), and unbiopsied NS (3). Proteinuria response was assessed as percent reduction from baseline and percent of patients meeting complete remission (final proteinuria <500 mg/d), partial remission (≥50 % reduction in proteinuria from baseline and final proteinuria 500–3500 mg/d), clinical response (≥30 % reduction in proteinuria from baseline that did not meet criteria for complete or partial remission), and no response (failed to meet remission or clinical response criteria) following Acthar gel therapy. Safety and tolerability were examined using adverse event (AE) frequency reported by patients or treating nephrologists and frequency of early discontinuation of treatment due to AEs.
Results
68.2 % (30/44) of patients had received prior NS treatment with immunosuppressive or cytotoxic therapies. Thirty-seven patients completed Acthar gel treatment. Seven patients (15.9 %) had early termination due to AEs, including weight gain (2), hypertension (2), edema (1), fatigue (1), seizures (1) and for reasons not stated (2). Proteinuria reduction ≥30 % was shown in 81.1 % (30/37) of patients and 62.2 % (23/37) showed ≥50 % proteinuria reduction. Proteinuria responses were greatest in MCD (n = 2/2 complete remission), MLN (n = 2/2 partial remission), MPGN (n = 1/1 partial remission), FSGS (n = 12/15 [80.0 %] partial remission or clinical response), and iMN (n = 8/11 [72.7 %] complete remission, partial remission, or clinical response).
Conclusions
Acthar gel may meet an important treatment need in patients with treatment-resistant NS in response to first-line therapies, patients unable to tolerate first-line therapies, and in patients with advanced disease.
doi:10.1186/s12882-016-0241-7
PMCID: PMC4815175  PMID: 27036111
ACTH; Acthar gel; Nephrotic syndrome; Proteinuria
12.  Prevalence of anti-phospholipase A2 receptor antibodies in Japanese patients with membranous nephropathy 
Background
Membranous nephropathy (MN) is the leading cause of nephrotic syndrome in adults. Anti-M-type phospholipase A2 receptor (anti-PLA2R) antibodies are found in most patients with idiopathic MN (iMN) worldwide, but the prevalence of anti-PLA2R antibodies among Japanese patients with MN is unknown. In this study, we determined the prevalence of anti-PLA2R antibodies in Japanese patients with MN.
Methods
The study population of our retrospective cross-sectional consisted of 131 patients with biopsy-proven MN who had not received any immunosuppressive treatments at time of both renal biopsy and serum sample collection. Of these, 100 had iMN and 31 had secondary MN (sMN). The circulating anti-PLA2R antibodies were analyzed using a highly sensitive Western blot analysis. Analysis was performed under non-reducing conditions with a human glomerular extract at serum dilutions of 1:25, 1:10, and 1 as the primary antibody.
Results
Anti-PLA2R antibodies were detected in 53 (53 %) of 100 patients with iMN and 0 (0 %) of 31 patients with sMN. The prevalence of anti-PLA2R antibodies was higher in patients with nephrotic syndrome (61 %) than in patients without nephrotic syndrome (43 %). The number of patients with serum albumin ≤3.0 g/dL was significantly higher in those with anti-PLA2R antibodies (92 %) than that in those without them (68 %).
Conclusions
Anti-PLA2R antibodies were found in Japanese patients with iMN; however, the prevalence was lower than that of any other Asian country. This may indicate that the presence of other pathogenic antigens plays a significant role in Japanese patients with iMN.
doi:10.1007/s10157-014-1054-2
PMCID: PMC4543411  PMID: 25412738
Phospholipase A2 receptor; Antibody; Membranous nephropathy; Prevalence; Japan; Western blot
13.  Smoking Is a Risk Factor for the Progression of Idiopathic Membranous Nephropathy 
PLoS ONE  2014;9(6):e100835.
Background
Multiple studies have shown cigarette smoking to be a risk factor for chronic kidney disease. However, it is unknown whether smoking similarly increases the risk for progression of membranous nephropathy.
Methods
This study used the Nagoya Nephrotic Syndrome Cohort Study (N-NSCS), including 171 patients with idiopathic membranous nephropathy (IMN) from 10 nephrology centers in Japan. The dose-response relationships between cigarette smoking and the outcomes were assessed by using multivariate Cox proportional hazards models adjusted for clinically relevant factors. The primary outcome was a 30% decline in the estimated glomerular filtration rate (eGFR). The secondary outcome was first complete remission (CR) of proteinuria.
Results
During the observation period (median, 37 months; interquartile range, 16–71 months), 37 (21.6%) patients developed a 30% decline in eGFR and 2 (1.2%) progressed to ESRD. CR occurred in 103 (60.2%) patients. Multivariate Cox proportional hazards models revealed current smoking (adjusted hazard ratio [HR], 7.81 [95% confidence interval (CI), 3.17–19.7]), female sex (adjusted HR, 3.58 [95% CI, 1.87–8.00]), older age (adjusted HR, 1.71 [95% CI, 1.13–2.62] per 10 years), the number of cigarettes smoked daily (adjusted HR, 1.61 [95% CI, 1.23–2.09] per 10 cigarettes daily), and cumulative smoking of ≥40 pack-years (adjusted HR, 5.56 [95% CI, 2.17–14.6]) to be associated with a 30% decline in eGFR. However, smoking was not associated with CR.
Conclusion
Smoking is a significant and dose-dependent risk factor for IMN progression. All patients with IMN who smoke should be encouraged to quit.
doi:10.1371/journal.pone.0100835
PMCID: PMC4071015  PMID: 24964146
14.  Patient Age and the Prognosis of Idiopathic Membranous Nephropathy 
PLoS ONE  2014;9(10):e110376.
Background
Idiopathic membranous nephropathy (IMN) is increasingly seen in older patients. However, differences in disease presentation and outcomes between older and younger IMN patients remain controversial. We compared patient characteristics between younger and older IMN patients.
Methods
We recruited 171 Japanese patients with IMN, including 90 (52.6%) patients <65 years old, 40 (23.4%) patients 65–70 years, and 41 (24.0%) patients ≥71 years. Clinical characteristics and outcomes were compared between younger and older IMN patients.
Results
During a median observation period of 37 months, 103 (60.2%) patients achieved complete proteinuria remission, which was not significantly associated with patient age (P = 0.831). However, 13 (7.6%) patients were hospitalized because of infection. Multivariate Cox proportional hazards models identified older age [adjusted hazard ratio (HR) = 3.11, 95% confidence interval (CI): 1.45–7.49, per 10 years; P = 0.003], prednisolone use (adjusted HR = 11.8, 95% CI: 1.59–242.5; P = 0.014), and cyclosporine used in combination with prednisolone (adjusted HR = 10.3, 95% CI: 1.59–204.4; P = 0.012) as significant predictors of infection. A <25% decrease in proteinuria at 1 month after immunosuppressive therapy initiation also predicted infection (adjusted HR = 6.72, 95% CI: 1.51–37.8; P = 0.012).
Conclusions
Younger and older IMN patients had similar renal outcomes. However, older patients were more likely to develop infection when using immunosuppressants. Patients with a poor response in the first month following the initiation of immunosuppressive therapy should be carefully monitored for infection and may require a faster prednisolone taper.
doi:10.1371/journal.pone.0110376
PMCID: PMC4203783  PMID: 25330372
15.  Effect of steroid and cyclosporine in membranous nephropathy that is resistant to steroid and/or cytotoxic treatment 
Membranous Nephropathy (MN) is a glomerular disease characterized by proteinuria. The etiology is unknown in many cases, while in some patients MN may be secondary to infection, to other diseases, or to exposure to drugs and toxic substances. The prognosis of the disease is variable, 1/3 of patients can have spontaneous remission; patients with nephrotic proteinuria, those with advanced tubulointerstitial changes and those with increased serum creatinine at presentation have a poorer prognosis. Although MN is one of the most common causes of adult-onset Nephrotic Syndrome (NS), its management is still controversial. Corticosteroids have been used for many years as the basic treatment, though with controversial results. Controversial results have been obtained with cytotoxic agents. Cyclosporine has been shown to be effective in the treatment of this disease. We have evaluated the results of 23 patients (14 males, 9 females aged between 26-53) diagnosed with Idiopathic MN (IMN) who have received cyclosporine because of the relapse or persistence after steroid and/or cytotoxic treatment. At the end of a 12-month follow-up, 8 patients had (34.8%) complete remission, 8 (34.8%) had partial remission, 2 (8.7%) had persistent proteinuria and 5 patients (21.7%) had no response to the treatment. There was a significant decrease in proteinuria throughout the study. There was no significant difference in total protein, albumin and creatinine levels between before and after the treatment. Our results indicate that patients with MN who do not respond well or have-relapse after steroid and/or cytotoxic therapy, should be offered cyclosporine. We think that in the future; long-term studies which are prospective and randomized with an extensive number of patients will be effective on the treatment of MN.
PMCID: PMC3902265  PMID: 24482713
Membranous nephropathy; steroid; cyclosporine
16.  Relapse or Worsening of Nephrotic Syndrome in Idiopathic Membranous Nephropathy Can Occur even though the Glomerular Immune Deposits Have Been Eradicated 
Nephron. Clinical Practice  2011;119(2):c145-c153.
Background: Relapse or worsening of nephrotic syndrome (NS) in idiopathic membranous nephropathy (IMN) is generally assumed to be due to recurrent disease. Here we document that often that may not be the case. Subjects and Methods: This is a prospective study of 7 consecutive IMN patients whose renal status improved, then worsened after completing a course of immunosuppressive therapy. Each underwent detailed testing and repeat kidney biopsy. Results: In 4 patients (group A), the biopsy showed recurrent IMN (fresh subepithelial deposits). Immunosuppressive therapy was begun. In the other 3 patients (group B), the biopsy showed that the deposits had been eradicated. However, the glomerular basement membrane (GBM) was thickened and vacuolated. Immunosuppressive therapy was withheld. Groups A and B were comparable except that group B had very high intakes of salt and protein, based on 24-hour urine testing. Reducing their high salt intake sharply lowered proteinuria to the subnephrotic range and serum creatinine stabilized. Conclusion: This work is the first to demonstrate that relapse/worsening of NS can occur in IMN even though the GBM deposits have been eradicated. High salt and protein intake in combination with thickened and vacuolated GBM appears to be the mechanism.
doi:10.1159/000324762
PMCID: PMC3214955  PMID: 21757952
Relapse of membranous nephropathy; Salt intake; Eradication of GBM deposits
17.  Immunosuppressive Treatment for Nephrotic Idiopathic Membranous Nephropathy: A Meta-Analysis Based on Chinese Adults 
PLoS ONE  2012;7(9):e44330.
Background
Idiopathic membranous nephropathy (IMN) is the most common pathological type for nephrotic syndrome in adults in western countries and China. The benefits and harms of immunosuppressive treatment in IMN remain controversial.
Objectives
To assess the efficacy and safety of different immunosuppressive agents in the treatment of nephrotic syndrome caused by IMN.
Methods
PubMed, EMBASE, Cochrane Library and wanfang, weipu, qinghuatongfang, were searched for relevant studies published before December 2011. Reference lists of nephrology textbooks, review articles were checked. A meta-analysis of randomized controlled trials (RCTs) meeting the criteria was performed using Review Manager.
Main Results
17 studies were included, involving 696 patients. Calcineurin inhibitors had a better effect when compared to alkylating agents, on complete remission (RR 1.61, 95% CI 1.13, to 2.30 P = 0.008), partial or complete remission (effective) (CR/PR, RR 1.29, 95% CI 1.09 to 1.52 P = 0.003), and fewer side effects. Among calcineurin inhibitors, tacrolimus (TAC) was shown statistical significance in inducing more remissions. When compared to cyclophosphamide (CTX), leflunomide (LET) showed no beneficial effect, mycophenolate mofetil (MMF) showed significant beneficial on effectiveness (CR/PR, RR: 1.41, 95% CI 1.16 to 1.72 P = 0.0006) but not significant on complete remission (CR, RR: 1.38, 95% CI 0.89 to 2.13 P = 0.15).
Conclusions
This analysis based on Chinese adults and short duration RCTs suggested calcineurin inhibitors, especially TAC, were more effective in proteinuria reduction in IMN with acceptable side effects. Long duration RCTs were needed to confirm the long-term effects of those agents in nephrotic IMN.
doi:10.1371/journal.pone.0044330
PMCID: PMC3434188  PMID: 22957065
18.  Spironolactone Plus Full-Dose ACE Inhibition in Patients with Idiopathic Membranous Nephropathy and Nephrotic Syndrome: Does It Really Work? 
Pharmaceuticals  2010;3(1):1-9.
We have studied the effects of add-on spironolactone treatment (100 mg/day) in 11 patients with idiopathic membranous nephropathy (IMN) and >3 gm proteinuria/day despite angiotensin converting enzyme (ACE) inhibitor therapy titrated to a systolic/diastolic blood pressure <120/80 mmHg. Blood pressure, 24-hour urinary protein excretion, and creatinine clearance were measured prior to, after two months of combined therapy, and after a 2-month withdrawal period of spironolactone. While systolic and diastolic blood pressure decreased significantly after spironolactone therapy, proteinuria did not improve. Serum potassium increased significantly as well, with three patients requiring resin-binding therapy. Thus, spironolactone seems to have no additional antiproteinuric effects over ACE inhibitor therapy in patients with IMN and nephrotic syndrome and carries the risk of significant hyperkalemia.
doi:10.3390/ph3010001
PMCID: PMC3991017
idiopathic membranous nephropathy; spironolactone; proteinuria; hyperkalemia
19.  High (≥6.5) Spontaneous and Persistent Urinary pH Is Protective of Renal Function at Baseline and during Disease Course in Idiopathic Membranous Nephropathy 
Metabolic acidosis correction in advanced renal failure slows renal function decline attributed to tubulointerstitial damage (TID) reduction. No study evaluated if spontaneous baseline high urinary pH (UpH) is renoprotective in patients with normal renal function and without metabolic acidosis. The study tested this hypothesis in idiopathic membranous nephropathy (IMN). Eighty-five patients (follow-up 81 ± 54 months) measured UpH, serum creatinine, eGFR, protein/creatinine ratio, fractional excretion of albumin, IgG, α1-microglobulin, and urinary N-acetyl-β-D-glucosaminidase (β-NAG)/creatinine ratio. Twenty-eight patients (33%) had UpH ≥ 6.5 and 57 (67%) pH < 6.5; high versus low UpH patients had significantly lower values of the tubulointerstitial damage (TID) markers FE α1m and β-NAG and significantly better baseline renal function. These differences persisted over time in a subset of 38 patients with 5 measurements along 53 ± 26 months. In 29 patients with nephrotic syndrome (NS) treated with supportive therapy (follow-up: 80 ± 52 months) renal function was stable in 10 high and significantly worse in 19 low UpH patients. Steroids + cyclophosphamide treatment in 35 NS patients masks the renoprotection of high UpH. Conclusions. In IMN high and persistent UpH is associated with reduction of the proteinuric markers of tubulointerstitial damage and baseline better renal function in all patients and in NS patients treated only with supportive therapy during disease course. The factors associated with high pH-dependent renoprotection were lower values of TID markers, eGFR ≥ 60 mL/min, BP < 140/90 mmHg, and age < 55 years.
doi:10.1155/2015/730234
PMCID: PMC4534628  PMID: 26294975
20.  Anti-Phospholipase A2 Receptor (PLA2R) Antibody and Glomerular PLA2R Expression in Japanese Patients with Membranous Nephropathy 
PLoS ONE  2016;11(6):e0158154.
The phospholipase A2 receptor (PLA2R) is the major target antigen (Ag) in idiopathic membranous nephropathy (IMN). Recently, several types of immunoassay systems for anti-PLA2R antibody (Ab) have been developed. However, the correlation of serum anti-PLA2R Abs and glomerular expression of PLA2R Ag, and their association with clinicopathological characteristics have yet to be proven in Japanese patients. We examined serum anti-PLA2R Abs by both ELISA and cell-based indirect immunofluorescence assay (CIIFA), and glomerular PLA2R expression by immunofluorescence (IF) in 59 biopsy-proven MN patients including IMN (n = 38) and secondary MN (SMN) (n = 21). In this study, anti-PLA2R Abs were present in 50% of IMN patients, but was absent in SMN patients. The concordance rate between ELISA and CIIFA was 100%. Serum IgG levels were significantly lower in anti-PLA2R Ab-positive patients. Serum albumin levels correlated inversely with serum anti-PLA2R Ab titers. The prevalence and intensity of glomerular staining for IgG4 by IF were significantly higher in anti-PLA2R Ab-positive patients than in -negative patients. Glomerular PLA2 Ag expression evaluated by IF was positive in 52.6% of IMN patients, but was absent in SMN patients. The concordance rate between the prevalence of glomerular PLA2R Ag expression and anti-PLA2R Ab was 84.2%. The prevalence of anti-PLA2R Abs measured by ELISA/CIIFA was equivalent to previous Japanese studies evaluated using Western blotting. These analyses showed an excellent specificity for the diagnosis of IMN, and anti-PLA2R positivity was associated with some clinicopathological features, especially glomerular IgG4-dominant deposition.
doi:10.1371/journal.pone.0158154
PMCID: PMC4927164  PMID: 27355365
21.  A pilot study to determine the dose and effectiveness of adrenocorticotrophic hormone (H.P. Acthar® Gel) in nephrotic syndrome due to idiopathic membranous nephropathy 
Nephrology Dialysis Transplantation  2014;29(8):1570-1577.
Background
H.P. Acthar® Gel is currently the only Food and Drug Administration therapy approved for the treatment of nephrotic syndrome. Active drug ingredients include structurally related melanocortin peptides that bind to cell surface G-protein-coupled receptors known as melanocortin receptors, which are expressed in glomerular podocytes. In animal models of membranous nephropathy, stimulation has been demonstrated to reduce podocyte injury and loss. We hypothesized that H.P. Acthar® Gel would improve symptoms of the nephrotic syndrome in patients with idiopathic membranous nephropathy.
Methods
Twenty patients received a subcutaneous dose of 40 or 80 IU twice weekly. Changes in proteinuria, albumin, cholesterol profile, estimated glomerular filtration rate and serum anti-PLA2R antibodies were assessed at baseline and in response to treatment along with tolerance and safety.
Results
Baseline characteristics included mean proteinuria (9.1 ± 3.4 g/day), albumin (2.7 ± 0.8 g/dL), estimated glomerular filtration rate (77 ± 30 mL/min) along with elevated total and low-density lipoprotein (LDL) cholesterol. By 12 months of follow-up, there was a significant improvement in proteinuria in the entire cohort, decreasing to 3.87 ± 4.24 g/day (P < 0.001) with significant improvements in serum albumin, total and LDL cholesterol. A >50% decrease in proteinuria was noted in 65% of the patients with a trend toward better outcomes among patients who received greater cumulative doses. No significant adverse effects were documented. Clearing of serum anti-PLA2R antibodies prior to or in parallel with proteinuria improvement was noted in some, but not all patients.
Conclusions
H.P. Acthar® Gel is a potential therapy for nephrotic syndrome secondary to idiopathic membranous nephropathy that deserves further study.
doi:10.1093/ndt/gfu069
PMCID: PMC4106642  PMID: 24714414
ACTH (H.P. Acthar® Gel); membranous nephropathy; nephrotic syndrome
22.  Association of phospholipase A2 receptor 1 polymorphisms with idiopathic membranous nephropathy in Chinese patients in Taiwan 
Background
Idiopathic membranous nephropathy (IMN) is one of the most common forms of autoimmune nephritic syndrome in adults. The purpose of this study is to evaluate whether polymorphisms of PLA2R1 affect the development of IMN.
Methods
Taiwanese-Chinese individuals (129 patients with IMN and 106 healthy controls) were enrolled in this study. The selected single nucleotide polymorphisms (SNPs) in PLA2R1 were genotyped by real-time polymerase chain reaction using TaqMan fluorescent probes, and were further confirmed by polymerase chain reaction-restriction fragment length polymorphism. The roles of the SNPs in disease progression were analyzed.
Results
Genotype distribution was significantly different between patients with IMN and controls for PLA2R1 SNP rs35771982 (p = 0.015). The frequency of G allele at rs35771982 was significantly higher in patients with IMN as compared with controls (p = 0.005). In addition, haplotypes of PLA2R1 may be used to predict the risk of IMN (p = 0.004). Haplotype H1 plays a role in an increased risk of IMN while haplotype H3 plays a protective role against this disease. None of these polymorphisms showed a significant and independent influence on the progression of IMN and the risk of end-stage renal failure and death (ESRF/death). High disease progression in patients having C/T genotype at rs6757188 and C/G genotype at rs35771982 were associated with a low rate of remission.
Conclusions
Our results provide new evidence that genetic polymorphisms of PLA2R1 may be the underlying cause of IMN, and the polymorphisms revealed by this study warrant further investigation.
doi:10.1186/1423-0127-17-81
PMCID: PMC2959017  PMID: 20937089
23.  Identification and Characterization of a New Autoimmune Protein in Membranous Nephropathy by Immunoscreening of a Renal cDNA Library 
PLoS ONE  2012;7(11):e48845.
Membranous Nephropathy (MN) represents a large amount of Nephrotic Syndromes in the adult population and its definitive diagnosis is currently carried out through biopsy. An autoimmune condition has been demonstrated in idiopathic MN (iMN) in which some kidney structures are targeted by patient autoantibodies. Some candidate antigens have been described and other likely involved target proteins responsible for the disease are not known yet. In this work our aim is to identify these proteins by screening a lambda-phage library with patients’ sera. We enrolled four groups of patients: two MN groups of 12 full iMN patients; one control group of 15 patients suffering from other renal diseases; one control group of 15 healthy individuals. A commercial cDNA phagemide library was screened using the above described sera, in order to detect positive signals due to antigen-antibody bond. We detected one phagemide clone expressing a protein which was shown to be targeted by the antibodies of the iMN sera only. Control sera were negative. The sequence analysis of cDNA matched the Synaptonemal Complex protein 65 (SC65) coding sequence. Further proteomic analyses were carried out to validate our results. We provide evidence of an involvement of SC65 protein as an autoimmune target in iMN. Considering the invasiveness and the resulting risk coming from renal biopsy, our ongoing aim is to set a procedure able to diagnose affected patients through a little- or non-invasive method such as blood sampling rather than biopsy.
doi:10.1371/journal.pone.0048845
PMCID: PMC3493607  PMID: 23144993
24.  TRPC6 Single Nucleotide Polymorphisms and Progression of Idiopathic Membranous Nephropathy 
PLoS ONE  2014;9(7):e102065.
Background
Activating mutations in the Transient Receptor Potential channel C6 (TRPC6) cause autosomal dominant focal segmental glomerular sclerosis (FSGS). TRPC6 expression is upregulated in renal biopsies of patients with idiopathic membranous glomerulopathy (iMN) and animal models thereof. In iMN, disease progression is characterized by glomerulosclerosis. In addition, a context-dependent TRPC6 overexpression was recently suggested in complement-mediated podocyte injury in e.g. iMN. Hence, we hypothesized that genetic variants in TRPC6 might affect susceptibility to development or progression of iMN.
Methods & Results
Genomic DNA was isolated from blood samples of 101 iMN patients and 292 controls. By direct sequencing of the entire TRPC6 gene, 13 single nucleotide polymorphisms (SNPs) were identified in the iMN cohort, two of which were causing an amino acid substitution (rs3802829; Pro15Ser and rs36111323, Ala404Val). No statistically significant differences in genotypes or allele frequencies between patients and controls were observed. Clinical outcome in patients was determined (remission n = 26, renal failure n = 46, persistent proteinuria n = 29, follow-up median 80 months {range 51–166}). The 13 identified SNPs showed no association with remission or renal failure. There were no differences in genotypes or allele frequencies between patients in remission and progressors.
Conclusions
Our data suggest that TRPC6 polymorphisms do not affect susceptibility to iMN, or clinical outcome in iMN.
doi:10.1371/journal.pone.0102065
PMCID: PMC4096511  PMID: 25019165
25.  The Relationship between Proteinuria and Coronary Risk: A Systematic Review and Meta-Analysis 
PLoS Medicine  2008;5(10):e207.
Background
Markers of kidney dysfunction such as proteinuria or albuminuria have been reported to be associated with coronary heart disease, but the consistency and strength of any such relationship has not been clearly defined. This lack of clarity has led to great uncertainty as to how proteinuria should be treated in the assessment and management of cardiovascular risk. We therefore undertook a systematic review of published cohort studies aiming to provide a reliable estimate of the strength of association between proteinuria and coronary heart disease.
Methods and Findings
A meta-analysis of cohort studies was conducted to obtain a summary estimate of the association between measures of proteinuria and coronary risk. MEDLINE and EMBASE were searched for studies reporting an age- or multivariate-adjusted estimate and standard error of the association between proteinuria and coronary heart disease. Studies were excluded if the majority of the study population had known glomerular disease or were the recipients of renal transplants. Two independent researchers extracted the estimates of association between proteinuria (total urinary protein >300 mg/d), microalbuminuria (urinary albumin 30–300 mg/d), macroalbuminuria (urinary albumin >300 mg/d), and risk of coronary disease from individual studies. These estimates were combined using a random-effects model. Sensitivity analyses were conducted to examine possible sources of heterogeneity in effect size. A total of 26 cohort studies were identified involving 169,949 individuals and 7,117 coronary events (27% fatal). The presence of proteinuria was associated with an approximate 50% increase in coronary risk (risk ratio 1.47, 95% confidence interval [CI] 1.23–1.74) after adjustment for known risk factors. For albuminuria, there was evidence of a dose–response relationship: individuals with microalbuminuria were at 50% greater risk of coronary heart disease (risk ratio 1.47, 95% CI 1.30–1.66) than those without; in those with macroalbuminuria the risk was more than doubled (risk ratio 2.17, 1.87–2.52). Sensitivity analysis indicated no important differences in prespecified subgroups.
Conclusion
These data confirm a strong and continuous association between proteinuria and subsequent risk of coronary heart disease, and suggest that proteinuria should be incorporated into the assessment of an individual's cardiovascular risk.
Vlado Perkovic and colleagues show, through a systematic review and meta-analysis of cohort studies, that there is a strong and continuous association between proteinuria and subsequent risk of coronary heart disease.
Editors' Summary
Background.
Coronary heart disease (CHD) is the leading cause of death among adults in developed countries. With age, fatty deposits called atherosclerotic plaques coat the walls of arteries, the vessels that nourish the organs of the body by carrying blood and oxygen to them. Because they narrow the arteries, atherosclerotic plaques restrict the blood flow to the body's organs. If these plaques form in the arteries that feed the heart muscle (the coronary arteries), the result is CHD. The symptoms of CHD include shortness of breath and chest pains (angina). In addition, if a plaque breaks off the wall of a coronary artery, it can completely block that artery, which kills part of the heart muscle and causes a potentially fatal heart attack. Smoking, high blood pressure, high blood levels of cholesterol (a type of fat), having diabetes, being overweight, and being physically inactive are established risk factors for CHD. Treatments for CHD include lifestyle changes (for example, losing weight) and medications that lower blood pressure and blood cholesterol. The narrowed arteries can also be widened using a device called a stent or surgically bypassed.
Why Was This Study Done?
In addition to the established risk factors for CHD, several other factors may also increase a person's risk of developing CHD, including kidney disease, which affects one in six adults to some degree. An early sign of kidney dysfunction is high amounts of a protein called albumin or of total proteins in the urine (albuminuria and proteinuria, respectively). Some studies have suggested that proteinuria is associated with an increased risk of CHD, but the results of these studies are inconsistent. Consequently, it is unclear whether proteinuria should be considered when assessing and managing an individual's CHD risk. In this study, the researchers undertake a systematic review (a study in which predefined search criteria are used to identify all the research on a specific topic) and a meta-analysis (a statistical method for combining the results of several studies) of published studies that have investigated the association between proteinuria and CHD.
What Did the Researchers Do and Find?
The researchers' systematic review identified 26 published studies that provided estimates of the association between CHD risk and proteinuria and albuminuria by measuring baseline urinary protein and albumin levels in people who were then followed for several years to see whether they developed CHD. Nearly 170,000 individuals participated in these studies, which recorded more 7,000 fatal and nonfatal heart attacks and other coronary events. In the meta-analysis, proteinuria (urinary protein of more than 300 mg/d or dipstick 1+ or more) increased CHD risk by 50% after adjustment for other known CHD risk factors. Furthermore, individuals with microalbuminuria (a urinary albumin of 30–300 mg/d) were 50% more likely to develop CHD than those with normal amounts of urinary albumin; people with macroalbuminuria (urinary albumin of more than 300 mg/d) were more than twice as likely to develop CHD. Finally, the association between proteinuria and CHD did not differ substantially between specific subgroups of participants such as people with and without diabetes.
What Do These Findings Mean?
These findings suggest that there is a strong, possibly dose-dependent association between proteinuria and the risk of CHD and that this association is independent of other known CHD risk factors, including diabetes. The finding that people with proteinuria have a 50% or greater increased risk of developing CHD than people without proteinuria may be a slight overestimate of the strength of the association between proteinuria because of publication bias. That is, studies that failed to show an association may not have been published. However, because this systematic review and meta-analysis includes several large population-based studies done in various parts of the world, these findings are likely to be generalizable. Thus, these findings support the inclusion of an evaluation of proteinuria in the assessment of CHD risk and suggest that medications and other strategies that reduce proteinuria might help to reduce the overall burden of CHD.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050207.
The MedlinePlus encyclopedia has pages on coronary heart disease, atherosclerosis, and chronic kidney failure (in English and Spanish)
Information is available from the US National Heart Lung and Blood Institute on coronary heart disease
The UK National Health Service Direct health encyclopedia also provides information about coronary heart disease (in several languages)
Information for patients and caregivers is provided by the American Heart Association on all aspects of heart disease.
The British Heart Foundation also provides information on heart disease and on keeping the heart healthy
doi:10.1371/journal.pmed.0050207
PMCID: PMC2570419  PMID: 18942886

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