Determination of the optimal target level of proteinuria in the management of patients with glomerular diseases by using different definitions of proteinuria.
ABSTRACT: Proteinuria is a major determinant of adverse renal outcome, and its reduction slows renal progression in glomerular diseases. However, the optimal target of proteinuria in glomerular diseases is unclear, and discrepancies in the definition of proteinuria produce ambiguous findings. Here we investigated the optimal target of proteinuria by using different definitions of proteinuria. We analyzed 574 IgA nephropathy (IgAN), 175 membranous nephropathy (MGN), and 177 focal segmental glomerulosclerosis (FSGS) cases from 3 Korean kidney centers. We evaluated the impact of proteinuria on renal outcome with 2 definitions: time-average proteinuria (TAP) and time-varying proteinuria (TVP). The endpoint was renal progression, defined as a 50% decline in glomerular filtration rate or end-stage renal disease. During a median follow-up of 57.3 months, the primary outcome occurred in 54 patients with IgAN, 26 with MGN, and 30 with FSGS. Multivariate Cox regression using TAP indicated that there was a linear association between proteinuria and risk of renal progression in IgAN. However, moderate proteinuria was not associated with an increased risk of renal progression in MGN and FSGS. In contrast, the analysis by TVP showed that the risk significantly increased in proportion to proteinuria during follow-up in all 3 diseases. Our findings suggest that TVP-based model can delineate association between proteinuria and risk of renal progression better than TAP-based model, considering that TVP reflects the dynamic change of proteinuria over time. Thus, proteinuria reduction to the lowest possible level is required to improve renal outcomes in patients with glomerular diseases.
Project description:The clinical course of IgA nephropathy (IgAN) and its outcome are extremely variable. Proteinuria at baseline has been considered one of the most important risk factors. More recently, mean proteinuria of follow-up (time-average proteinuria: TAp) was described as a stronger marker of renal survival, suggesting to consider it as a marker of disease activity and response to treatment. We evaluated predictors of renal survival in IgAN patients with different degrees of renal dysfunction and histological lesions, focusing on the role of the therapy in influencing TAp. We performed a retrospective analysis of three prospective, randomized, clinical trials enrolling 325 IgAN patients from 1989 to 2005. Patients were divided into 5 categories according to TAp. The primary endpoint of the 100% increase of serum creatinine occurred in 54 patients (16.6%) and renal survival was much better in groups having lower TAp. The median follow up was 66.6 months (range 12 to 144). The primary endpoint of the 100% increase of serum creatinine occurred in 54 patients (16,6%) and renal survival was much better in groups having lower TA proteinuria. At univariate analysis plasma creatinine and 24h proteinuria, systolic (SBP) and diastolic (DBP) blood pressure during follow-up and treatment with either steroid (CS) or steroid plus azathioprine (CS+A) were the main factors associated with lower TAp and renal survival. At multivariate analysis, female gender, treatment with S or S+A, lower baseline proteinuria and SBP during follow-up remained as the only variables independently influencing TAp. In conclusion, TA-proteinuria is confirmed as one of the best outcome indicators, also in patients with a severe renal insufficiency. A 6-month course of corticosteroids seems the most effective therapy to reduce TAp.
Project description:In CKD, the risk of kidney failure and death depends on the severity of proteinuria, which correlates with the extent of podocyte loss and glomerular scarring. We investigated whether proteinuria contributes directly to progressive glomerulosclerosis through the suppression of podocyte regeneration and found that individual components of proteinuria exert distinct effects on renal progenitor survival and differentiation toward a podocyte lineage. In particular, albumin prevented podocyte differentiation from human renal progenitors in vitro by sequestering retinoic acid, thus impairing retinoic acid response element (RARE)-mediated transcription of podocyte-specific genes. In mice with Adriamycin nephropathy, a model of human FSGS, blocking endogenous retinoic acid synthesis increased proteinuria and exacerbated glomerulosclerosis. This effect was related to a reduction in podocyte number, as validated through genetic podocyte labeling in NPHS2.Cre;mT/mG transgenic mice. In RARE-lacZ transgenic mice, albuminuria reduced retinoic acid bioavailability and impaired RARE activation in renal progenitors, inhibiting their differentiation into podocytes. Treatment with retinoic acid restored RARE activity and induced the expression of podocyte markers in renal progenitors, decreasing proteinuria and increasing podocyte number, as demonstrated in serial biopsy specimens. These results suggest that albumin loss through the damaged filtration barrier impairs podocyte regeneration by sequestering retinoic acid and promotes the generation of FSGS lesions. Our findings may explain why reducing proteinuria delays CKD progression and provide a biologic rationale for the clinical use of pharmacologic modulators to induce regression of glomerular diseases.
Project description:Minimal Change Disease (MCD) is a clinical condition characterized by acute nephrotic syndrome, no evident renal lesions at histology and good response to steroids. However, frequent recurrence of the disease requires additional therapies associated with steroids. Such multi-drug dependence and frequent relapses may cause disease evolution to focal and segmental glomerulosclerosis (FSGS) over time. The differences between the two conditions are not well defined, since molecular mechanisms may be shared by the two diseases. In some cases, genetic analysis can make it possible to distinguish MCD from FSGS; however, there are cases of overlap. Several hypotheses on mechanisms underlying MCD and potential molecular triggers have been proposed. Most studies were conducted on animal models of proteinuria that partially mimic MCD and may be useful to study glomerulosclerosis evolution; however, they do not demonstrate a clear-cut separation between MCD and FSGS. Puromycin Aminonucleoside and Adriamycin nephrosis are models of glomerular oxidative damage, characterized by loss of glomerular basement membrane polyanions resembling MCD at the onset and, at more advanced stages, by glomerulosclerosis resembling FSGS. Also Buffalo/Mna rats present initial lesions of MCD, subsequently evolving to FSGS; this mechanism of renal damage is clearer since this rat strain inherits the unique characteristic of overexpressing Th2 cytokines. In Lipopolysaccharide nephropathy, an immunological condition of renal toxicity linked to B7-1(CD80), mice develop transient proteinuria that lasts a few days. Overall, animal models are useful and necessary considering that they reproduce the evolution from MCD to FSGS that is, in part, due to persistence of proteinuria. The role of T/Treg/Bcells on human MCD has been discussed. Many cytokines, immunomodulatory mechanisms, and several molecules have been defined as a specific cause of proteinuria. However, the hypothesis of a single cell subset or molecule as cause of MCD is not supported by research and an interactive process seems more logical. The implication or interactive role of oxidants, Th2 cytokines, Th17, Tregs, B7-1(CD80), CD40/CD40L, c-Mip, TNF, uPA/suPAR, Angiopoietin-like 4 still awaits a definitive confirmation. Whole genome sequencing studies could help to define specific genetic features that justify a definition of MCD as a "clinical-pathology-genetic entity."
Project description:BACKGROUND:The serum immunoglobulin A (IgA)/C3 ratio is considered to be an effective predictor of IgA nephropathy (IgAN). This study sought to explore the diagnostic value of the IgA/C3 ratio in IgAN among primary glomerular nephropathy patients in China. METHODS:We recruited 1095 biopsy-diagnosed primary glomerular nephropathy patients, including 757 IgAN patients and 338 non-IgAN patients. Patient demographics, serum immunological indices, and other clinical examinations were measured. IgAN cases were propensity score matched (PSM) to non-IgAN cases on the logit of the propensity score using nearest neighbor matching in a 1:1 fashion, with a caliper of 0.02 with no replacements, according to age, gender, BMI, proteinuria level, and estimated glomerular filtration rate (eGFR). RESULTS:We found that in both the full cohort and PSM cohort, the IgA/C3 ratio in the IgAN group was significantly higher than that of the non-IgAN group. The same results were also obtained with stratification by different levels of proteinuria and renal function. In the PSM cohort, there was no difference in IgA/C3 ratio in patients with IgAN between different proteinuria groups and different chronic kidney disease (CKD) groups. The area under the ROC curve (AUROC) of the IgA/C3 ratio in distinguishing IgAN among primary glomerular disease was 0.767 in the full cohort, and 0.734 in the PSM cohort. The highest AUROC of the IgA/C3 ratio was in the ≤1 g/d proteinuria group (0.801 in the full cohort, and 0.803 in the PSM cohort); however, there was no difference between all CKD groups. Meanwhile, the diagnostic accordance rate for the diagnosis of IgAN among all patients with an IgA/C3 ratio > 3.5304 was as high as 92.02% in the full cohort. IgAN was independently correlated with IgA/C3 ratio in the full cohort by multivariate logistic regression analysis. CONCLUSIONS:The present study provides clear evidence that the IgA/C3 ratio is an effective predictor of IgA diagnosis, especially in patients with proteinuria ≤1 g/d. In order to study the effectiveness of this biomarker, and to determine a standardized cut-off value, additional multicenter large-scale studies are needed.
Project description:Introduction:Idiopathic focal segmental glomerulosclerosis (FSGS) is a leading cause of nephrotic syndrome and end-stage renal disease. In preclinical models and biopsies of human FSGS kidneys, p38 mitogen-activated protein kinase (MAPK) has demonstrated enhanced activity; and p38 MAPK inhibition has improved disease markers. This proof-of-concept trial aimed to assess efficacy, safety, tolerability, and pharmacokinetics of losmapimod, an oral p38 MAPK inhibitor, in humans with FSGS. Methods:A single-arm, multicenter, open-label, Phase II trial (NCT02000440) was conducted in adults with FSGS; proteinuria ?2.0 g/d; estimated glomerular filtration rate (eGFR) ?45 ml/min per 1.73 m2; blood pressure <140/90 mm Hg. Collapsing and genetic forms of FSGS were excluded. The primary endpoint was number of patients with ?50% proteinuria reduction and eGFR ?70% of baseline after receiving losmapimod twice-daily for 16 to 24 weeks. Results:Seventeen patients received ?1 losmapimod dose. No patients achieved the primary endpoint; therefore, the study was terminated following a prespecified interim analysis. At week 24, proteinuria reductions between 20% and <50% were observed in 4 patients and proteinuria increases >20% in 3 patients. One patient achieved a proteinuria response (?50% reduction) at week 2 but subsequently relapsed. Losmapimod pharmacokinetics were consistent with prior studies. No serious adverse events (AEs) were reported. Conclusion:p38 MAPK inhibition with losmapimod did not result in ?50% reduction of proteinuria in patients with FSGS. However, study population heterogeneity may have contributed to our negative findings and therefore this does not eliminate the potential to demonstrate benefit in a population more sensitive to p38 MAPK inhibition if identifiable in the future by precision-medicine methods.
Project description:Focal segmental glomerulosclerosis (FSGS) comprises a group of uncommon disorders that present with marked proteinuria, nephrotic syndrome, progressive renal failure and characteristic glomerular lesions on histopathology. The current standard of care for patients with FSGS include immunosuppressive drugs such as glucocorticoids followed by calcineurin inhibitors, if needed for intolerance or inadequate response to glucocorticoids. Renin-angiotensin-aldosterone (RAAS) blockers are also used to control proteinuria, an important signature of FSGS. Existing treatments, however, achieved only limited success. Despite best care, treatment failure is common and FSGS is causal in a significant proportion of end stage renal disease. Thus, an unmet need exists for novel disease modifying treatments for FSGS. We employed two widely-used murine models of FSGS to test the hypothesis that systemic inhibition of chemokine receptor CCR2 would have therapeutic benefit. Here we report that administration CCX872, a potent and selective small molecule antagonist of CCR2, achieved rapid and sustained attenuation of renal damage as determined by urine albumin excretion and improved histopathological outcome. Therapeutic benefit was present when CCX872 was used as a single therapy, and moreover, the combination of CCX872 and RAAS blockade was statistically more effective than RAAS blockade alone. In addition, the combination of CCR2 and RAAS blockade was equally as effective as endothelin receptor inhibition. We conclude that specific inhibition of CCR2 is effective in the Adriamycin-induced and 5/6 nephrectomy murine models of FSGS, and thus holds promise as a mechanistically distinct therapeutic addition to the treatment of human FSGS.
Project description:Proteinuria is a powerful prognostic factor for end-stage renal disease in IgA nephropathy (IgAN) patients. However, it is not known whether proteinuria exacerbations are related to seasonal changes.We retrospectively enrolled consecutive patients diagnosed with IgAN by kidney biopsy at our hospital between 2002 and 2014. Proteinuria remission was defined as urinary protein <0.3 g/gCr in two consecutive outpatient urinalyses and exacerbation as urinary protein ?0.75 g/gCr. Four seasons were defined: spring (March-May), summer (June-August), autumn (September-November), and winter (December-February). We performed a multivariate analysis to identify factors associated with the second remission following a proteinuria exacerbation.We analyzed 116 patients. Proteinuria remission and exacerbation occurred in 77, and 43 patients, respectively. The incidence of proteinuria exacerbation was significantly higher in autumn and winter than in spring and summer (p = 0.040). The cumulative second remission rate was significantly higher in patients with autumn and winter proteinuria exacerbation than in patients with spring and summer exacerbations (p = 0.0091). In multivariate analyses, exacerbation onset in autumn and winter (hazard ratio [HR], 3.51; 95% confidence interval [CI], 1.41-8.74) and intensive therapy (HR, 2.26; 95% CI, 1.05-4.88) were significantly associated with a second proteinuria remission.In IgAN patients in proteinuria remission, proteinuria exacerbation frequently occurred in autumn and winter. Exacerbations occurring in autumn and winter tended to remit early.
Project description:Hyperuricemia is an independent risk factor for renal progression in IgA nephropathy (IgAN). However, no study has evaluated the effect of allopurinol on the clinical outcome in hyperuricemic IgAN.First,a retrospective cohort study of 353 IgAN patients was conducted to explore the relationship between uric acid (UA) and the progression of renal disease over a mean period of 5 years. Then, 40 hyperuricemic IgAN patients were randomized to receive allopurinol (100-300 mg/day) or usual therapy for 6 months. The study outcomes were renal disease progression and/or blood pressure.Hyperuricemia independently predicted renal survival at 1, 3, and 5 years after adjustment for different baseline estimated glomerular filtration rates. In the randomized controlled trial, allopurinol did not significantly alter renal progression or proteinuria. The antihypertensive drug dosage was reduced in 7 of 9 cases with hypertension in the allopurinol group compared to 0 of 9 cases in the control group (p < 0.01). UA levels correlated with mean arterial pressure in normotensive patients (r = 0.388, p < 0.001).Hyperuricemia predicts the progression of IgAN independently of baseline estimated glomerular filtration rate. Allopurinol may improve the control of blood pressure. Further studies are required to explore the effects of lowering UA on renal protection in IgAN.
Project description:Membranous glomerulonephritis (MGN) represents an immunologically mediated disease characterized by deposition of immune complexes in the glomerular subepithelial space. Persistent proteinuria at diagnosis predicts poor prognosis. Pregnancy with MGN is a risk of fetal loss and may worsen maternal renal function.Here, we report a lady with MGN and proteinuria achieved spontaneous remission and successful fetal outcome naive to any medications. The 26-year old woman had 1-year history of persistent proteinuria (5.5-12.56?g/24?hours) and biopsy-proven MGN. Histopathological characteristics included glomerular basement membrane spikes, subepithelial monoclonal IgG immunofluorescence, and diffuse electron dense deposits. She was sticking to a regular morning exercise routine without any medications. After successful delivery of a full-term baby girl, the mother had improved proteinuria (0.56?g/24?hours) and albuminuria (351.96?g/24?hours contrasting 2281.6?g/24?hours before pregnancy). The baby had normal height and body weight at 4 months old.We identified more pregnancies with MGN in 5 case reports and 5 clinical series review articles (7-33 cases included). Spontaneous remission of maternal MGN with good fetal outcome rarely occurred in mothers on immunosuppressive therapy.Mothers naive to immunosuppressive therapy may achieve spontaneous remission of maternal membranous glomerulonephritis and successful fetal outcome. Theoretically, fetus might donate stem cells to heal mother's kidney.
Project description:BACKGROUND:Urinary miRNAs may potentially serve as noninvasive biomarkers in various kidney diseases to reflect disease activity, severity and progression, especially those correlated with the pathogenesis of kidney diseases. This study demonstrates that urinary miR-196a, a kidney-enriched miRNA, can predict progression of chronic kidney disease (CKD). METHODS:Focal segmental glomerulosclerosis (FSGS) cohorts were used as the representative example of CKD. First, correlation of miR-196a with disease activity was analyzed using paired urine and plasma samples from FSGS patients with nephrotic-range proteinuria (FSGS-A), complete remission (FSGS-CR) and normal controls (NCs). Then, the value of urinary miR-196a in predicting disease progression was validated using another cohort of 231 FSGS patients who were followed-up until over 36 months or reaching end-stage renal disease (ESRD). MiR-196a levels were analyzed by quantitative reverse transcription-polymerase chain reaction. RESULTS:The results showed that urinary miR-196a significantly increased in FSGS-A compared with FSGS-CR and NCs, clearly distinguishing FSGS-A from FSGS-CR and NCs, whereas plasma miR-196a showed no difference among these groups. Moreover, urinary miR-196a, which was associated with proteinuria, estimated glomerular filtration rate (eGFR), interstitial fibrosis and tubular atrophy, significantly increased in patients progressed to ESRD compared to those not. Furthermore, patients with higher urinary miR-196a displayed poorer renal survival than those with lower urinary miR-196a. Multivariate Cox analysis confirmed urinary miR-196a as an independent risk factor for FSGS progression after adjusting for age, sex, proteinuria and eGFR. Prediction accuracy of ESRD was significantly improved by combining urinary miR-196a with other indicators including eGFR and proteinuria. CONCLUSION:Urinary miR-196a may serve as a biomarker for predicting CKD progression.