Outcome of relapse in lupus nephritis: roles of reversal of renal fibrosis and response of inflammation to therapy

Machine Learning for Prediction and Risk Stratification of Lupus Nephritis Renal Flare

BACKGROUND

Renal flare of lupus nephritis (LN) is strongly associated with poor kidney outcomes, and predicting renal flare and stratifying its risk are important for clinical decision-making and individualized management to reduce LN flare.

METHODS

We randomly divided 1,694 patients with biopsy-proven LN, who had achieved remission after treatment, into a derivation cohort (n = 1,186) and an internal validation cohort (n = 508), at a ratio of 7:3. The risk of renal flare 5 years after remission was predicted using an eXtreme Gradient Boosting (XGBoost) method model, developed from 59 variables, including demographic, clinical, immunological, pathological, and therapeutic characteristics. A simplified risk score prediction model (SRSPM) was developed from important variables selected by XGBoost model using stepwise Cox regression for practical convenience.

RESULTS

The 5-year relapse rates were 39.5% and 38.2% in the derivation and internal validation cohorts, respectively. Both the XGBoost model and the SRSPM had good predictive performance, with a C-index of 0.819 (95% confidence interval [CI]: 0.774-0.857) and 0.746 (95% CI: 0.697-0.795), respectively, in the validation cohort. The SRSPM comprised 6 variables, including partial remission and endocapillary hypercellularity at baseline, age, serum Alb, anti-dsDNA, and serum complement C3 at the point of remission. Using Kaplan-Meier analysis, the SRSPM identified significant risk stratification for renal flares (p < 0.001).

CONCLUSIONS

Renal flare of LN can be readily predicted using the XGBoost model and the SRSPM, and the SRSPM can also stratify flare risk. Both models are useful for clinical decision-making and individualized management in LN.

Per-protocol repeat kidney biopsy portends relapse and long-term outcome in incident cases of proliferative lupus nephritis

OBJECTIVES

In patients with LN, clinical and histological responses to treatment have been shown to be discordant. We investigated whether per-protocol repeat kidney biopsies are predictive of LN relapses and long-term renal function impairment.

METHODS

Forty-two patients with incident biopsy-proven active proliferative (class III/IV±V) LN from the database of the UCLouvain were included in this retrospective study. Per-protocol repeat biopsies were performed after a median [interquartile range (IQR)] time of 24.3 (21.3-26.2) months. The National Institutes of Health activity index (AI) and chronicity index (CI) scores were assessed in all biopsies.

RESULTS

Despite a moderate correlation between urinary protein/creatinine ratios (UPCR) and AI scores at repeat biopsy (r = 0.48; P = 0.001), 10 patients (23.8%) with UPCR < 1.0 g/g still had a high degree of histological activity (AI > 3). High AI scores (continuous) in repeat biopsies were associated with an increased probability and/or shorter time to renal relapse (n = 11) following the repeat biopsy [hazard ratio (HR) = 1.2, 95% CI: 1.1, 1.3; P = 0.007], independently of proteinuria levels. High CI scores (continuous) in repeat biopsies were associated with a sustained increase in serum creatinine levels corresponding to ≥120% of the baseline value (HR = 1.8, 95% CI: 1.1, 2.9; P = 0.016) through a median (IQR) follow-up time of 131.5 (73.8-178.2) months, being also the case for acute tubulointerstitial inflammation and interstitial fibrosis/tubular atrophy in repeat but not baseline biopsies.

CONCLUSION

Our results highlight the usefulness of per-protocol repeat biopsies, herein performed after a median time of 24 months from baseline, as an integral part of the treatment evaluation, also in patients showing adequate clinical response.

ND-13, a DJ-1-Derived Peptide, Attenuates the Renal Expression of Fibrotic and Inflammatory Markers Associated with Unilateral Ureter Obstruction

DJ-1 is a redox-sensitive chaperone with reported antioxidant and anti-inflammatory properties in the kidney. The 20 amino acid (aa) peptide ND-13 consists of 13 highly conserved aas from the DJ-1 sequence and a TAT-derived 7 aa sequence that helps in cell penetration. This study aimed to determine if ND-13 treatment prevents the renal damage and inflammation associated with unilateral ureter obstruction (UUO). Male C57Bl/6 and DJ-1^-/- mice underwent UUO and were treated with ND-13 or vehicle for 14 days. ND-13 attenuated the renal expression of fibrotic markers TGF-β and collagen1a1 (Col1a1) and inflammatory markers TNF-α and IL-6 in C57Bl/6 mice. DJ-1^-/- mice treated with ND-13 presented similar decreased expression of TNF-α, IL-6 and TGF-β. However, in contrast to C57Bl/6 mice, ND-13 failed to prevent renal fibrosis or to ameliorate the expression of Col1a1 in this genotype. Further, UUO led to elevated urinary levels of the proximal tubular injury marker neutrophil gelatinase-associated lipocalin (NGAL) in DJ-1^-/- mice, which were blunted by ND-13. Our results suggest that ND-13 protects against UUO-induced renal injury, inflammation and fibrosis. These are all crucial mechanisms in the pathogenesis of kidney injury. Thus, ND-13 may be a new therapeutic approach to prevent renal diseases.

Pharmacokinetics of Enteric-Coated Mycophenolate Sodium in Lupus Nephritis (POEMSLUN)

BACKGROUND

Mycophenolate mofetil or enteric-coated mycophenolate sodium (EC-MPS) and steroids are used for induction and maintenance therapy in severe lupus nephritis. Blood concentrations of mycophenolic acid (MPA), the active metabolite of these drugs, vary among patients with lupus nephritis. The objective of this study was to examine whether concentration-controlled (CC) dosing (through therapeutic drug monitoring) of EC-MPS results in a higher proportion of participants achieving target exposure of MPA compared with fixed-dosing (FD). An additional aim of the study was to evaluate the influence of CC dosing on clinical outcomes.

METHODS

Nineteen participants were randomly assigned either to the FD or CC group. All the participants were eligible to have free and total measurements of MPA over a period of 8-12 hours on 3 different occasions. Area under the concentration-time curve between 0 and 12 hours (AUC0-12) was calculated using noncompartmental methods. Dose of EC-MPS was titrated according to AUC0-12 in the CC group.

RESULTS

Thirty-two AUC0-12 measurements were obtained from 9 FD and 9 CC participants. Large inter-patient variability was observed in both groups but was more pronounced in the FD group. There were no significant differences between FD and CC participants in any pharmacokinetic parameters across the study visits, except for total C0 (FD 2.0 ± 0.3 mg/L versus CC 1.1 ± 0.3; P = 0.01) and dose-normalized C0 (FD 2.9 ± 0.2 mg/L/g versus CC 2.1 ± 0.7 mg/L/g; P = 0.04) at the second visit and total AUC0-12 (FD 66.6 ± 6.0 mg·h/L versus CC 35.2 ± 11.4 mg·h/L; P = 0.03) at the third visit. At the first study visit, 33.3% of the FD and 11.1% of the CC participants achieved the target area under the concentration-time curve (P = 0.58). From the second visit, none of the FD participants, compared with all the CC participants, achieved target AUC0-12 (P = 0.01). More CC participants achieved remission compared with FD participants (absolute difference of -22.2, 95% confidence interval (Equation is included in full-text article.)0.19 to 0.55; P = 0.62). The mean free MPA AUC0-12 was significantly lower in those who had complete remission.

CONCLUSIONS

CC participants reached target AUC0-12 quicker. Larger studies are required to test clinical efficacy.

Contribution of Clinically Indicated Repeat Renal Biopsy in Indian Patients with Lupus Nephritis

Background:

Repeat renal biopsy is usually done for lupus nephritis (LN) flare or resistant disease. We analyzed the changes between first and repeat biopsy and the contribution of repeat biopsy on renal outcome in LN patients.

Methods:

This was a retrospective study carried out at a tertiary care center in India. Sixty-two LN patients who underwent repeat biopsy for clinical indications, between January 2012 to December 2016, were included. Clinical and histological parameters at first and second biopsies were compared. Logistic regression analysis was done to determine parameters on repeat biopsy predicting response at last visit.

Results:

Repeat biopsy was done for relapse in 56% and for resistant disease in 44% patients. Seven (13.7%) out of 51 patients with baseline proliferative histology converted to non-proliferative lesion on second biopsy, while 2 (18.2%) out of 11 with baseline non-proliferative lesion converted to proliferative lesion on second biopsy. On repeat biopsy, the presence of endocapillary proliferation decreased, whereas glomerulosclerosis, interstitial fibrosis/tubular atrophy (IFTA), and glomerular basement membrane thickening increased. At the last visit (median follow-up of 38.6 months after first biopsy and 13.8 months after second biopsy), 79% of patients were in remission and 6.5% needed renal replacement therapy. The presence of IFTA >30% and thrombotic microangiopathy (TMA) on second biopsy independently predicted response at last visit.

Conclusion:

In Indian patients with LN, chronicity markers and superimposed membranous pattern increased on repeat biopsy done for clinical indications. The presence of IFTA and TMA on second biopsy predicted response at last visit.

IL-34-Dependent Intrarenal and Systemic Mechanisms Promote Lupus Nephritis in MRL-Faslpr Mice

BACKGROUND

In people with SLE and in the MRL-Fas^lpr lupus mouse model, macrophages and autoantibodies are central to lupus nephritis. IL-34 mediates macrophage survival and proliferation, is expressed by tubular epithelial cells (TECs), and binds to the cFMS receptor on macrophages and to a newly identified second receptor, PTPRZ.

METHODS

To investigate whether IL-34-dependent intrarenal and systemic mechanisms promote lupus nephritis, we compared lupus nephritis and systemic illness in MRL-Fas^lpr mice expressing IL-34 and IL-34 knockout (KO) MRL-Fas^lpr mice. We also assessed expression of IL-34 and the cFMS and PTPRZ receptors in patients with lupus nephritis.

RESULTS

Intrarenal IL-34 and its two receptors increase during lupus nephritis in MRL-Fas^lpr mice. In knockout mice lacking IL-34, nephritis and systemic illness are suppressed. IL-34 fosters intrarenal macrophage accumulation via monocyte proliferation in bone marrow (which increases circulating monocytes that are recruited by chemokines into the kidney) and via intrarenal macrophage proliferation. This accumulation leads to macrophage-mediated TEC apoptosis. We also found suppression of circulating autoantibodies and glomerular antibody deposits in the knockout mice. This is consistent with fewer activated and proliferating intrarenal and splenic B cells in mice lacking IL-34, and with our novel discovery that PTPRZ is expressed by macrophages, B and T cells. These findings appear translatable to human patients with lupus nephritis, whose expression of IL-34, cFMS, and PTPRZ is similar to that seen in the MRL-Fas^lpr lupus mouse model. Moreover, expression of IL-34 in TECs correlates with disease activity.

CONCLUSIONS

IL-34 is a promising novel therapeutic target for patients with lupus nephritis.

Urinary vitamin D-binding protein, a novel biomarker for lupus nephritis, predicts the development of proteinuric flare

Lupus nephritis (LN) is a major complication of systemic lupus erythematosus (SLE). Conventional biomarkers for assessing renal disease activity are imperfect in predicting clinical outcomes associated with LN. The aim of this study is to identify urinary protein biomarkers that reliably reflect the disease activity or predict clinical outcomes. A quantitative proteomic analysis was performed to identify protein biomarker candidates that can differentiate between SLE patients with and without LN. Selected biomarker candidates were further verified by enzyme-linked immunosorbent assay using urine samples from a larger cohort of SLE patients ( n = 121) to investigate their predictive values for LN activity measure. Furthermore, the association between urinary levels of a selected panel of potential biomarkers and prognosis of LN was assessed with a four-year follow-up study of renal outcomes. Urinary vitamin D-binding protein (VDBP), transthyretin (TTR), retinol binding protein 4 (RBP4), and prostaglandin D synthase (PTGDS) were significantly elevated in SLE patients with LN, especially in patients with active LN ( n = 21). Among them, VDBP well correlated with severity of proteinuria (rho = 0.661, p < 0.001) and renal SLE Disease Activity Index (renal SLEDAI) (rho = 0.520, p < 0.001). In the four-year follow-up, VDBP was a significant risk factor (hazard ratio 9.627, 95% confidence interval 1.698 to 54.571, p = 0.011) for the development of proteinuric flare in SLE patients without proteinuria ( n = 100) after adjustments for multiple confounders. Urinary VDBP correlated with proteinuria and renal SLEDAI, and predicted the development of proteinuria.

The clinical relevance of repeat renal biopsies in the management of lupus nephritis: a South African experience

Purpose Clinically, repeat renal biopsies (RRBs) have been performed in lupus nephritis to identify changes in class, plan treatment and assist in prognostication. We set out to compare the histopathological features and outcomes of disease flare and protocol biopsy patients. Methods A retrospective descriptive study was conducted on repeat biopsies performed between January 1984 and December 2015 in lupus nephritis patients. Disease flares and protocol biopsies were compared. Results Of 614 systemic lupus erythematosus (SLE) renal biopsies, 127 (20.7%) RRBs were identified. Disease flare patients accounted for 96 (75.6%) and protocol biopsies for 31 (24.4%) of RRBs. Seventy (72.9%) disease flare patients retained their original class on repeat biopsy. When categorised as proliferative and non-proliferative histology, 83 (87.4%) of the disease flare biopsy patients remained histologically unchanged. Treatment remained unchanged in 57 (60.0%) patients following RRBs for disease flares. Response to immunosuppression in disease flare patients was poorer. Non-response was associated with increased chronicity index (OR = 1.33; 95% CI 1.01-1.76; p = 0.045). Thirty-three (36.3%) disease flare patients developed end-stage kidney disease (ESKD) in one year as compared to one (3.6%) protocol biopsy patient ( p = 0.003). ESKD in disease flare patients was associated with non-response to treatment (OR = 24.6; 95% CI 2.7-219.3; p = 0.004) on multivariate analysis. One-year mortality was 30.0% in the disease flare patients and 3.5% in protocol biopsy patients ( p = 0.018). Conclusion Repeat biopsies in disease flare patients infrequently led to histological class changes, failed to lead to change of treatment in the majority of patients, and were associated with poorer outcomes.

Hypokalemic Paralysis: A Hidden Card of Several Autoimmune Diseases

Acute hypokalemic paralysis is a rare and potentially fatal condition, with few related causes, one of which highlights distal renal tubular acidosis (dRTA). Distal renal tubular acidosis is a rare complication of several autoimmune diseases such as systemic lupus erythematosus, Sjögren's syndrome, and Hashimoto thyroiditis. We report a case of a lupic patient who presented rapidly progressive quadriparesis in the context of active renal disease. Research revealed severe refractory hypokalemia, metabolic acidosis, and alkaline urine suggestive of dRTA. We diagnosed Sjögren's syndrome based on sicca symptoms, an abnormal salivary glands' nuclear scan and the presence of anti-Ro/SSA and anti-La/SSB. In addition, the finding of thyroid peroxidase, thyroglobulin antibodies, and hypothyroidism led us to the diagnosis of Hashimoto thyroiditis. Due to the active renal involvement on the context of systemic lupus erythematosus and Sjögren's syndrome, the patient received immunosuppression with rituximab, resulting in a progressive and complete improvement.

Histologic versus clinical remission in proliferative lupus nephritis

BACKGROUND

Treatment response in lupus nephritis (LN) is defined clinically, without consideration of renal histology. Few studies have systematically examined histologic responses to induction therapy. In LN patients who underwent protocol kidney biopsies after induction immunosuppression, we describe the renal histology of the second biopsy and correlate histologic activity and damage with short- and long-term kidney outcomes.

METHODS

Patients with suspected LN were biopsied for diagnosis (Biopsy 1), and those with proliferative LN were rebiopsied after induction (Biopsy 2). Histologic activity and damage at each biopsy were calculated as the National Institutes of Health activity and chronicity indices. Complete and partial renal responses after induction and after long-term follow-up were determined clinically.

RESULTS

One-third of patients who achieved a complete clinical response after induction had persistently high histologic activity, and 62% of patients who had complete histologic remission on rebiopsy were still clinically active. Chronic renal damage increased after induction even in complete clinical responders. Chronicity at Biopsy 2 associated with long-term kidney function and development of chronic kidney disease.

CONCLUSIONS

Early clinical and histologic outcomes are discordant in proliferative LN, and neither correlates with long-term renal outcome. The kidney accrues chronic damage rapidly and despite clinical response in LN. Preservation of kidney function may require therapeutic targeting of both chronic damage and inflammation during LN induction treatment.

Clinical and Histopathologic Characteristics Associated with Renal Outcomes in Lupus Nephritis

BACKGROUND AND OBJECTIVES

The prognostic significance of histopathologic (sub)classes in the current classification of lupus nephritis (LN) is controversial. We analyzed clinical and histopathologic predictors of renal outcome in LN outside the framework of the classification.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Variables (50 histopathologic and ten clinical) were tested in mixed, linear, and Cox regression models for their association with renal flare, ESRD, and eGFR during follow-up (1, 5, and 10 years) in 105 patients with LN who underwent biopsy from 1987 to 2011. The Cockcroft-Gault (normalized to a body surface area of 1.73 m2) and Schwartz formulas were used to calculate eGFR for adults and children, respectively.

RESULTS

During median follow-up of 9.9 years (25th-75th percentile, 5.9-13.8), 47 patients experienced a renal flare and 21 progressed to ESRD. Renal flare was predicted by fibrinoid necrosis (hazard ratio [HR], 1.04 per %; 95% confidence interval [95% CI], 1.00 to 1.07) and nonwhite race (HR, 2.23; 95% CI, 1.23 to 4.04). ESRD was predicted by fibrinoid necrosis (HR, 1.08 per %; 95% CI, 1.02 to 1.13), fibrous crescents (HR, 1.09 per %; 95% CI, 1.02 to 1.17), interstitial fibrosis/tubular atrophy (IF/TA) ≥25% (HR, 3.89; 95% CI, 1.25 to 12.14), eGFR at baseline (HR, 0.98 per ml/min per 1.73 m2; 95% CI, 0.97 to 1.00), and nonwhite race (HR, 7.16; 95% CI, 2.34 to 21.91). A higher mean eGFR during follow-up was associated with normal glomeruli (+0.2 ml/min per 1.73 m2 per %; 95% CI, 0.1 to 0.4). Like ESRD, a lower eGFR during follow-up was associated with fibrous crescents, IF/TA≥25%, and nonwhite race, as well as with cellular/fibrocellular crescents (-0.4 ml/min per 1.73 m2 per %; 95% CI, -0.6 to -0.2) and age (-0.8 ml/min per 1.73 m2 per year; 95% CI, -1.2 to -0.4).

CONCLUSION

The LN classification should include an index of evidence-based prognosticators. Awaiting validation of a formal index, we suggest that at least fibrinoid necrosis, fibrous crescents, and IF/TA warrant explicit independent scoring to assess the risk of progressive renal dysfunction in conjunction with clinical findings.

A framework for remission in SLE: consensus findings from a large international task force on definitions of remission in SLE (DORIS)

Objectives

Treat-to-target recommendations have identified ‘remission’ as a target in systemic lupus erythematosus (SLE), but recognise that there is no universally accepted definition for this. Therefore, we initiated a process to achieve consensus on potential definitions for remission in SLE.

Methods

An international task force of 60 specialists and patient representatives participated in preparatory exercises, a face-to-face meeting and follow-up electronic voting. The level for agreement was set at 90%.

Results

The task force agreed on eight key statements regarding remission in SLE and three principles to guide the further development of remission definitions:

1. Definitions of remission will be worded as follows: remission in SLE is a durable state characterised by …………………. (reference to symptoms, signs, routine labs).

2. For defining remission, a validated index must be used, for example, clinical systemic lupus erythematosus disease activity index (SLEDAI)=0, British Isles lupus assessment group (BILAG) 2004 D/E only, clinical European consensus lupus outcome measure (ECLAM)=0; with routine laboratory assessments included, and supplemented with physician's global assessment.

3. Distinction is made between remission off and on therapy: remission off therapy requires the patient to be on no other treatment for SLE than maintenance antimalarials; and remission on therapy allows patients to be on stable maintenance antimalarials, low-dose corticosteroids (prednisone ≤5 mg/day), maintenance immunosuppressives and/or maintenance biologics.

The task force also agreed that the most appropriate outcomes (dependent variables) for testing the prognostic value (construct validity) of potential remission definitions are: death, damage, flares and measures of health-related quality of life.

Conclusions

The work of this international task force provides a framework for testing different definitions of remission against long-term outcomes.

Pristane-Accelerated Autoimmune Disease in (SWR X NZB) F1 Mice Leads to Prominent Tubulointerstitial Inflammation and Human Lupus Nephritis-Like Fibrosis

Mouse models lupus nephritis (LN) have provided important insights into disease pathogenesis, although none have been able to recapitulate all features of the human disease. Using comprehensive longitudinal analyses, we characterized a novel accelerated mouse model of lupus using pristane treatment in SNF1 (SWR X NZB F1) lupus prone mice (pristane-SNF1 mice). Pristane treatment in SNF1 mice accelerated the onset and progression of proteinuria, autoantibody production, immune complex deposition and development of renal lesions. At week 14, the pristane-SNF1 model recapitulated kidney disease parameters and molecular signatures seen in spontaneous disease in 36 week-old SNF1 mice and in a traditional IFNα-accelerated NZB X NZW F1 (BWF1) model. Blood transcriptome analysis revealed interferon, plasma cell, neutrophil, T-cell and protein synthesis signatures in the pristane-SNF1 model, all known to be present in the human disease. The pristane-SNF1 model appears to be particularly useful for preclinical research, robustly exhibiting many characteristics reminiscent of human disease. These include i) a stronger upregulation of the cytosolic nucleic acid sensing pathway, which is thought to be key component of the pathogenesis of the human disease, and ii) more prominent kidney interstitial inflammation and fibrosis, which have been both associated with poor prognosis in human LN. To our knowledge, this is the only accelerated model of LN that exhibits a robust tubulointerstitial inflammatory and fibrosis response. Taken together our data show that the pristane-SNF1 model is a novel accelerated model of LN with key features similar to human disease.

The Kidney Biopsy in Lupus Nephritis: Past, Present, and Future

Since its incorporation into clinical practice in the 1950s, the percutaneous kidney biopsy has played an important role in advancing our understanding of lupus nephritis (LN). The biopsy findings have been used to classify and subgroup LN in order to obtain an accurate diagnosis and also to inform treatment decisions and predict prognosis. Several classifications schemes have been applied clinically however despite this evolution in histopathologic classification, our ability to predict treatment response and determine prognosis remains limited. In this review we will examine the evolving role of the kidney biopsy in the management of LN, including the potentially larger role the biopsy could play in the future.

Association of Relapse with Renal Outcomes under the Current Therapy Regimen for IgA Nephropathy: A Multi-Center Study

Background and Objectives

Renal relapse is a very common manifestation of IgA nephropathy (IgAN). The clinical characteristics and long-term outcomes of this condition have not yet been carefully explored.

Design and Patients

Patients with biopsy-proven IgAN between January 2005 and December 2010 from three medical centers in China was a primary cohort of patients. From January 2010 to April 2012, data of an independent cohort of IgAN patients from Ren Ji Hospital, Shanghai, China was collected using the same inclusion and exclusion criteria. These patients formed the validation cohort of this study.

Results

Of the patients with biopsy-proven IgAN from three medical centers, 489 patients achieved remission within 6 months following the therapy. Additionally, 76 (15.5%) of these patients experienced a relapse after achieving remission. During the median follow-up period of 66 months, 6 patients (1.4%) in the non-relapse group experienced renal deterioration, compared with 22 patients (29.6%) in the relapse group. Our study indicated that each 1-mmHg increase in the baseline diastolic blood pressure (DBP) was associated with a 4.5% increase in the risk of renal relapse; additionally, the male patients had a 3.324-fold greater risk of relapse compared with the female patients according to the adjusted multivariate Cox analysis. The nomogram was based on 489 patients achieved remission. The predictive accuracy and discriminative ability of the nomogram were determined by concordance index (C-index) and calibration curve. The results were validated using bootstrap resampling on the validation cohort.

Conclusions

This study demonstrated that renal relapse is a potential predictor of prognostic outcomes in patients under the current therapeutic regimens for IgAN. And male patients with higher diastolic blood pressure had a greater risk of experiencing relapse.

High collagen I gene expression as an independent predictor of adverse renal outcomes in lupus nephritis patients with preserved renal function

CONTEXT

The deposition of extracellular matrix is a major pathogenic mechanism leading to fibrosis and progressive decline in renal function in patients with lupus nephritis (LN). Currently, available clinicopathologic features cannot predict renal outcome consistently.

OBJECTIVE

To test that the expression of renal fibrogenic genes correlates with renal fibrosis at the time of biopsy and is predictive of renal outcomes.

DESIGN

Renal gene expression levels of transforming growth factor β-1 (TGFB1), and collagen I (COL1) were studied by real-time multiplex quantitative polymerase chain reaction in a prospective cohort of patients with LN (n = 39). Extracellular matrix index (ECMI) and collagen I/III matrix index were measured from Picro-Sirius Red-stained slides under normal and polarized light, respectively.

RESULTS

After follow-up (median, 43.9 months), renal failure (50% reduction in glomerular filtration rate [GFR] or dialysis) had developed in 13 subjects. The expression levels of renal fibrogenic genes were increased as compared to controls without LN. COL1 correlated with collagen I/III matrix index at baseline. Both high expression of TGFB1 or COL1 tended to predict renal failure by univariate analysis. By multivariate analysis, high ECMI and low GFR were predictive of renal failure. In patients with baseline GFR of 60 mL/min/1.73 m(2) or greater, high renal COL1 expression was an independent (hazard ratio = 4.4, P = .04) predictor of renal failure.

CONCLUSIONS

High renal COL1 expression is a strong predictor of adverse renal outcome in patients with LN and preserved baseline GFR. These findings support larger prospective studies to confirm the benefits of COL1 in identifying patients at high risk of progression to renal disease.

A critical role of the transcription factor fli-1 in murine lupus development by regulation of interleukin-6 expression

OBJECTIVE

The Fli-1 transcription factor is implicated in the pathogenesis of systemic lupus erythematosus (SLE), both in humans and in animal models. Dysregulation of interleukin-6 (IL-6) is also associated with SLE. The purpose of this study was to investigate whether Fli-1 directly regulates the expression of IL-6.

METHODS

Sera were collected from wild-type and Fli-1-heterozygous (Fli-1(+/-) ) MRL/lpr mice, and the concentration of IL-6 was measured by enzyme-linked immunosorbent assay (ELISA). Expression of IL-6 in the kidney was measured by real-time polymerase chain reaction analysis. T cells were isolated from wild-type and Fli-1(+/-) MRL/lpr mice and stimulated with CD3/CD28 beads, and the concentration of IL-6 in the supernatants was measured by ELISA. MS1 endothelial cells were transfected with Fli-1 and control small interfering RNA, and the production of IL-6 was compared after lipopolysaccharide stimulation. A chromatin immunoprecipitation (ChIP) assay was performed to determine whether Fli-1 binds to the IL-6 promoter region. Transient transfections with the NIH3T3 cell line were performed to examine whether Fli-1 regulates the expression of IL-6.

RESULTS

Fli-1(+/-) MRL/lpr mice had significantly decreased IL-6 levels in sera and reduced expression of IL-6 in kidneys as compared to their wild-type littermates. T cells isolated from Fli-1(+/-) MRL/lpr mice produced less IL-6 than did those from wild-type mice. Inhibiting the expression of Fli-1 in endothelial cells resulted in reduced production of IL-6. The ChIP assay revealed direct binding of Fli-1 to 3 regions within the IL-6 promoter. Fli-1 activated transcription from the IL-6 promoter in a dose-dependent manner.

CONCLUSION

The direct regulation of IL-6 expression by Fli-1 represents one possible mechanism for the protective effect of decreased Fli-1 expression in lupus.

Value of repeat biopsy in lupus nephritis flares

Objectives

Renal flares are common in lupus nephritis (LN), and class switch is thought to be characteristic. There is no agreement on indications for performing a repeat renal biopsy. Our objective was to retrospectively review patients who had more than one renal biopsy performed on clinical indications, and analyse clinical, pathological and treatment changes after successive biopsies.

Methods

Forty-five patients with LN and one or more repeat renal biopsies were included, with a total of 116 biopsies.

Results

Of the 71 repeat biopsies, pathological transition occurred in 39 (54.9%). When having a previous biopsy with a proliferative lesion, class switch occurred in 55.6%, with 24.4% evolving into non-proliferative classes. When previous biopsy was class V, transition to other classes occurred in 58.3% and changes were all into proliferative classes. Conversion from one pure proliferative form to another (class III to class IV or vice versa) happened in 11.3% of the rebiopsies, with 62 rebiopsies (87.3%) leading to a change in the treatment regimen.

Conclusions

Histological transformations were common, and they occurred when the previous biopsy had non-proliferative lesions as well as when lesions were proliferative. Treatments were modified after repeat renal biopsy in the majority of patients. In this experience, kidney repeat biopsies were useful in guiding treatment of LN flares.

Class I and II histone deacetylase inhibition by ITF2357 reduces SLE pathogenesis in vivo

We sought to determine if a specific class I and II HDAC inhibitor (ITF2357) was able to decrease disease in lupus-prone NZB/W mice through regulation of T cell profiles. From 22 to 38 weeks-of-age, NZB/W and non-lupus NZW mice were treated with ITF2357 (5 mg/kg or 10 mg/kg), or vehicle control. Body weight and proteinuria were measured every 2 weeks, while sera anti-dsDNA and cytokine levels were measured every 4 weeks. Kidney disease was determined by sera IgG levels, immune complex deposition, and renal pathology. T lymphocyte profiles were assessed using flow cytometric analyses. Our results showed that NZB/W mice treated with the 10 mg/kgof ITF2357 had decreased renal disease and inflammatory cytokines in the sera. Treatment with ITF2357 decreased the Th17 phenotype while increasing the percentage of Tregs as well as Foxp3 acetylation. These results suggest that specific HDAC inhibition may decrease disease by altering T cell differentiation and acetylation.

The serum levels of connective tissue growth factor in patients with systemic lupus erythematosus and lupus nephritis

OBJECTIVE

The expression of connective tissue growth factor mRNA in human kidneys may serve as an early marker for lupus nephritis progression. Therefore, we speculated that connective tissue growth factor may be involved in the pathogenesis of systemic lupus erythematosus and lupus nephritis. In this study, we set out to investigate the associations between serum connective tissue growth factor levels and clinicopathological features of patients with systemic lupus erythematosus and lupus nephritis.

METHODS

Serum samples from patients with non-renal systemic lupus erythematosus, renal biopsy-proven lupus nephritis and healthy control subjects were detected by enzyme-linked immunosorbent assay for serum connective tissue growth factor levels. The associations between connective tissue growth factor levels and clinicopathological features of the patients were further analysed.

RESULTS

The levels of serum connective tissue growth factor in patients with non-renal systemic lupus erythematosus and lupus nephritis were both significantly higher than those in the normal control group (34.14 ± 12.17 ng/ml vs. 22.8 ± 3.0 ng/ml, p<0.001; 44.1 ± 46.8 ng/ml vs. 22.8 ± 3.0 ng/ml, p = 0.035, respectively). There was no significant difference of the serum connective tissue growth factor levels between non-renal systemic lupus erythematosus and lupus nephritis group (34.14 ± 12.17 ng/ml vs. 44.1 ± 46.8 ng/ml, p = 0.183). Serum connective tissue growth factor levels were significantly higher in lupus nephritis patients with the following clinical manifestations, including anaemia (51.3 ± 51.4 ng/ml vs. 23.4 ± 9.7 ng/ml, p<0.001) and acute renal failure (85.5 ± 75.0 ng/ml vs. 31.2 ± 21.8 ng/ml, p = 0.002). Serum connective tissue growth factor levels in class IV were significantly higher than that in class II, III and V (57.6 ± 57.5 ng/ml vs. 18.7 ± 6.4 ng/ml, p = 0.019; 57.6 ± 57.5 ng/ml vs. 25.2 ± 14.9 ng/ml, p = 0.006; 57.6 ± 57.5 ng/ml vs. 30.5 ± 21.3 ng/ml, p = 0.017, respectively). Serum connective tissue growth factor levels were significantly higher in those with both active/chronic lesions than those in those with active lesions only in either class IV (84.9 ± 69.6 ng/ml vs. 40.0 ± 40.2 ng/ml, p = 0.001) or in combination of class III and IV lupus nephritis (63.3 ± 63.4 ng/ml vs. 38.3 ± 37.9 ng/ml, p = 0.035, respectively). Serum connective tissue growth factor levels were negatively associated with estimated glomerular filtration rate (r = -0.46, p<0.001) and positively associated with interstitial inflammation (r = 0.309, p = 0.002) and interstitial fibrosis (r = 0.287, p = 0.004). Serum connective tissue growth factor level was a risk factor for doubling of serum creatinine in lupus nephritis (p<0.001, hazard ratio = 1.015, 95% confidence intervals 1.008-1.022) in univariate analysis.

CONCLUSIONS

Serum connective tissue growth factor levels were significantly higher in lupus and correlated with chronic renal interstitial injury and doubling of serum creatinine in patients with lupus nephritis.

A Protocol for the Pharmacokinetics of Enteric Coated Mycophenolate Sodium in Lupus Nephritis (POEMSLUN): an open-label, randomised controlled trial

INTRODUCTION

Mycophenolate sodium, an enteric-coated tablet (EC-MPS), is as effective and safe as mycophenolate mofetil (MMF) in preventing transplant rejection. EC-MPS and MMF improve the outcome of severe lupus nephritis (LN) and have fewer side effects than pulsed intravenous cyclophosphamide. Blood concentrations of mycophenolic acid (MPA), the active metabolite of EC-MPS, vary between participants despite fixed dosing. Interpatient variability has been studied in transplantation, but not well documented in LN. The relationship between MPA concentration and its clinical effect on LN has not been described.

METHODS AND ANALYSIS

This is a prospective, open-label, randomised controlled trial. -32 participants with LN who meet the inclusion and exclusion criteria will be randomised into two groups: one receiving a fixed dose of EC-MPS and the second, a dosing regimen that is titrated with therapeutic drug monitoring. Included participants will have blood sampled over a period of 8-12 h on three different occasions. Pharmacokinetic parameters will be calculated using non-compartmental methods.

ETHICS AND DISSEMINATION

The Human Research and Ethics Committee of the Royal Brisbane Women's Hospital have approved this study. The study is registered with Australian and New Zealand Clinical Trials Registry-ACTRN12611000798965 We planned to present the de-identified information at conferences and publish the results in medical journals.

TRIAL REGISTRATION

ACTRN12611000798965.

Diagnosis and treatment of lupus nephritis flares--an update

Relapses or flares of systemic lupus erythematosus (SLE) are frequent and observed in 27-66% of patients. SLE flares are defined as an increase in disease activity, in general, requiring alternative treatment or intensification of therapy. A renal flare is indicated by an increase in proteinuria and/or serum creatinine concentration, abnormal urine sediment or a reduction in creatinine clearance rate as a result of active disease. The morbidity associated with renal flares is derived from both the kidney damage due to lupus nephritis and treatment-related toxic effects. Current induction treatment protocols achieve remission in the majority of patients with lupus nephritis; however, few studies focus on treatment interventions for renal flares in these patients. The available data, however, suggest that remission can be induced again in a substantial percentage of patients experiencing a lupus nephritis flare. Lupus nephritis flares are independently associated with an increased risk of deterioration in renal function; prevention of renal flares might, therefore, also decrease long-term morbidity and mortality. Appropriate immunosuppressive maintenance therapy might lead to a decrease in the occurrence of renal and extrarenal flares in patients with SLE, and monitoring for the early detection and treatment of renal flares could improve their outcomes.

Joint European League Against Rheumatism and European Renal Association-European Dialysis and Transplant Association (EULAR/ERA-EDTA) recommendations for the management of adult and paediatric lupus nephritis

OBJECTIVES

To develop recommendations for the management of adult and paediatric lupus nephritis (LN).

METHODS

The available evidence was systematically reviewed using the PubMed database. A modified Delphi method was used to compile questions, elicit expert opinions and reach consensus.

RESULTS

Immunosuppressive treatment should be guided by renal biopsy, and aiming for complete renal response (proteinuria <0.5 g/24 h with normal or near-normal renal function). Hydroxychloroquine is recommended for all patients with LN. Because of a more favourable efficacy/toxicity ratio, as initial treatment for patients with class III-IV(A) or (A/C) (±V) LN according to the International Society of Nephrology/Renal Pathology Society 2003 classification, mycophenolic acid (MPA) or low-dose intravenous cyclophosphamide (CY) in combination with glucocorticoids is recommended. In patients with adverse clinical or histological features, CY can be prescribed at higher doses, while azathioprine is an alternative for milder cases. For pure class V LN with nephrotic-range proteinuria, MPA in combination with oral glucocorticoids is recommended as initial treatment. In patients improving after initial treatment, subsequent immunosuppression with MPA or azathioprine is recommended for at least 3 years; in such cases, initial treatment with MPA should be followed by MPA. For MPA or CY failures, switching to the other agent, or to rituximab, is the suggested course of action. In anticipation of pregnancy, patients should be switched to appropriate medications without reducing the intensity of treatment. There is no evidence to suggest that management of LN should differ in children versus adults.

CONCLUSIONS

Recommendations for the management of LN were developed using an evidence-based approach followed by expert consensus.

Cross-species transcriptional network analysis defines shared inflammatory responses in murine and human lupus nephritis

Lupus nephritis (LN) is a serious manifestation of systemic lupus erythematosus. Therapeutic studies in mouse LN models do not always predict outcomes of human therapeutic trials, raising concerns about the human relevance of these preclinical models. In this study, we used an unbiased transcriptional network approach to define, in molecular terms, similarities and differences among three lupus models and human LN. Genome-wide gene-expression networks were generated using natural language processing and automated promoter analysis and compared across species via suboptimal graph matching. The three murine models and human LN share both common and unique features. The 20 commonly shared network nodes reflect the key pathologic processes of immune cell infiltration/activation, endothelial cell activation/injury, and tissue remodeling/fibrosis, with macrophage/dendritic cell activation as a dominant cross-species shared transcriptional pathway. The unique nodes reflect differences in numbers and types of infiltrating cells and degree of remodeling among the three mouse strains. To define mononuclear phagocyte-derived pathways in human LN, gene sets activated in isolated NZB/W renal mononuclear cells were compared with human LN kidney profiles. A tissue compartment-specific macrophage-activation pattern was seen, with NF-κB1 and PPARγ as major regulatory nodes in the tubulointerstitial and glomerular networks, respectively. Our study defines which pathologic processes in murine models of LN recapitulate the key transcriptional processes active in human LN and suggests that there are functional differences between mononuclear phagocytes infiltrating different renal microenvironments.

Connective tissue growth factor gene expression and decline in renal function in lupus nephritis

In lupus nephritis (LN), kidney inflammation may be followed by fibrosis and progressive decline in function. Transforming growth factor (TGF)-β is a notable mediator of fibrosis, but it has other beneficial roles, thus indicating a need for alternate therapeutic targets for inhibition of fibrosis. Connective tissue growth factor (CTGF) acts as a downstream mediator of TGF-β in promoting fibrosis, without mediating the immunosuppressive effects of TGF-β. Animal studies show that CTGF may have important roles in renal fibrosis, but data are limited in human subjects. The present study tested the hypothesis that renal CTGF mRNA expression is related to TGF-β1 and collagen I expression and is predictive of renal function deterioration in patients with LN (n=39). Gene expression was measured using multiplex real-time quantitative RT-PCR and renal function was estimated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) glomerular filtration rate (GFR) equation. Decline in GFR was assessed by regression of GFR at biopsy to 1 year following biopsy. CTGF mRNA expression was significantly correlated with TGF-β1 and collagen I. GFR at biopsy was 89.2±39.2 ml/ min. Renal CTGF mRNA expression correlated inversely with baseline GFR. Renal CTGF mRNA was significantly higher in patients with moderate to severe CKD compared to those in the milder CKD group (low GFR 4.92±4.34 vs. high GFR 1.52±1.94, p<0.005). CTGF mRNA was also higher in patients with subsequent decline in GFR [GFR decline (5.19±4.46) vs. no GFR decline (1.79±1.97); P<0.01]. In conclusion, renal expression of CTGF was positively related to TGF-β1 and collagen I in patients with LN. Furthermore, high CTGF mRNA expression was associated with poor GFR at baseline and subsequent deterioration of kidney function. CTGF expression in the kidney may serve as an early marker for renal disease progression and could be evaluated as a target for therapeutic intervention to prevent renal failure in LN.

Adipose tissue-derived stem cell treatment prevents renal disease progression

Adipose tissue-derived stem cells (ASCs) are an attractive source of stem cells with regenerative properties that are similar to those of bone marrow stem cells. Here, we analyze the role of ASCs in reducing the progression of kidney fibrosis. Progressive renal fibrosis was achieved by unilateral clamping of the renal pedicle in mice for 1 h; after that, the kidney was reperfused immediately. Four hours after the surgery, 2 × 10(5) ASCs were intraperitoneally administered, and mice were followed for 24 h posttreatment and then at some other time interval for the next 6 weeks. Also, animals were treated with 2 × 10(5) ASCs at 6 weeks after reperfusion and sacrificed 4 weeks later to study their effect when interstitial fibrosis is already present. At 24 h after reperfusion, ASC-treated animals showed reduced renal dysfunction and enhanced regenerative tubular processes. Renal mRNA expression of IL-6 and TNF was decreased in ASC-treated animals, whereas IL-4, IL-10, and HO-1 expression increased despite a lack of ASCs in the kidneys as determined by SRY analysis. As expected, untreated kidneys shrank at 6 weeks, whereas the kidneys of ASC-treated animals remained normal in size, showed less collagen deposition, and decreased staining for FSP-1, type I collagen, and Hypoxyprobe. The renal protection seen in ASC-treated animals was followed by reduced serum levels of TNF-α, KC, RANTES, and IL-1α. Surprisingly, treatment with ASCs at 6 weeks, when animals already showed installed fibrosis, demonstrated amelioration of functional parameters, with less tissue fibrosis observed and reduced mRNA expression of type I collagen and vimentin. ASC therapy can improve functional parameters and reduce progression of renal fibrosis at early and later times after injury, mostly due to early modulation of the inflammatory response and to less hypoxia, thereby reducing the epithelial-mesenchymal transition.

A composite urine biomarker reflects interstitial inflammation in lupus nephritis kidney biopsies

The initial treatment of lupus nephritis is usually based on a renal biopsy. Subsequent disease flares, however, are often treated without the benefit of kidney pathology because repeat biopsies are infrequent. A noninvasive, real-time method to assess renal pathology would be useful to adjust treatment and improve outcome. To develop such a method we collected urine samples at or close to the time of 64 biopsies from 61 patients with lupus nephritis to identify potential biomarkers of tubulointerstitial inflammation and correlated these to biopsy parameters scored by a renal pathologist using a semiquantitative scale. Linear discriminant analysis was used to weight variables and derive composite biomarkers that identified the level of tubulointerstitial inflammation based on urine concentrations of monocyte chemotactic protein-1, hepcidin (a marker of active lupus), and liver fatty acid-binding protein. The discriminant function that described the most accurate composite biomarkers included urine monocyte chemotactic protein-1 and serum creatinine as the independent variables. This composite had sensitivity, specificity, positive predictive value, and negative predictive value of 100, 81, 67, and 100%, respectively. Only 14% of the biopsies were misclassified. Thus, specific renal pathologic lesions can be modeled by composite biomarkers to noninvasively follow and adjust the treatment of lupus nephritis reflecting renal injury.

Review: Lupus nephritis: pathologic features, epidemiology and a guide to therapeutic decisions

Systemic lupus erythematosus may present with renal manifestations that frequently are difficult to categorize and lupus nephritis is an important predictor of poor outcome. The type and spectrum of renal injury may remain undiagnosed until full-blown nephritic and/or nephrotic syndrome appear with increased risk of end-stage renal disease. These abnormalities occur within the first few years after the diagnosis of lupus is made on clinical grounds and with the support of laboratory tests in high risk patients. An early renal biopsy is helpful in patients with an abnormal urinalysis and/or reduced glomerular filtration rate and the results form the basis for therapeutic decisions. The biopsy also provides vital prognostic information based on histological categorization of different types of lupus nephritis, the degree of activity, chronicity and the immunopathogenesis. In the current armamentarium, the use of cyclophosphamide and azathioprine and recently mycophenolate mofetil, reduce morbidity and maintenance therapies reduce the risk of end-stage renal disease. Clinical trials underway promise new, effective and safe immunosuppressive regimens for the treatment of proliferative lupus nephritis.

The clinical relevance of a repeat biopsy in lupus nephritis flares

BACKGROUND

The clinical utility of performing repeat biopsies during lupus nephritis flares is questionable and data pointing towards frequent class switches are based on the old WHO classification. This retrospective study investigates the hypothesis that clinically relevant switches from proliferative to non-proliferative lesions and vice versa as determined by the new ISN/RPS classification are a rare event and that repeat biopsies are unnecessary in many cases.

METHODS

Thirty-five patients with lupus nephritis and one or more repeat renal biopsies were included. Eighty-four biopsies were blindly reassessed according to the ISN/RPS classification.

RESULTS

Twenty-five patients had one repeat biopsy, 6 patients had two and 4 patients had three repeat biopsies. Forty-nine comparisons between reference and repeat biopsies could be made. In 25 cases (54.3%), there was no shift in ISN/RPS class on repeat biopsies. In 41 instances, paired biopsies showed proliferative lesions both on reference and repeat biopsies, whereas five of six cases with non-proliferative lesions on a reference biopsy switched to proliferative lesions on a repeat biopsy. Clinically significant class switches during lupus nephritis flares were more frequent in patients with non-proliferative lesions in their reference biopsy (P < 0.001).

CONCLUSION

The results show that patients with proliferative lesions in the original biopsy rarely switch to a pure non-proliferative nephritis during a flare. Therefore, a repeat biopsy during a lupus nephritis flare is frequently not necessary if proliferative lesions were found in the reference biopsy. However, in the case of a non-proliferative lesion in the reference biopsy, class switches are frequently found and repeat biopsies are advisable.

Clinicopathological characteristics and outcomes of patients with crescentic lupus nephritis

There are few clinicopathologic and outcome data on patients with crescentic lupus nephritis, therefore, we determined factors of the disease by retrospectively reviewing the records of 327 patients diagnosed with lupus nephritis. Of these, 152 cases were regrouped as class IV-G, including 33 patients with crescentic glomerulonephritis. Significantly, all patients with crescentic glomerulonephritis had acute kidney injury as compared with only about a quarter of the patients without the disease. On pathological evaluation, activity scores, chronicity indexes, relapse rates, and the frequency of positive serum anti-neutrophil cytoplasmic antibody (ANCA) were each significantly higher, whereas complete remission rates and renal outcomes, over a mean follow-up of 4 years, were significantly poorer in patients with crescentic glomerulonephritis. Our study shows that crescentic glomerulonephritis was not rare in patients with lupus nephritis and that their long-term outcome was poor. The precise role of ANCA in the pathologic course of crescentic lupus nephritis remains to be determined.

Renal disease in systemic lupus erythematosus with emphasis on classification of lupus glomerulonephritis: advances and implications

CONTEXT

Systemic lupus erythematosus is an autoimmune disease with protean clinical and pathologic manifestations involving almost all organs in the body. There is a high incidence of renal involvement during the course of the disease, with varied renal pathologic lesions and diverse clinical features. A renal biopsy examined by routine light microscopy, immunofluorescence, and electron microscopy contributes toward diagnosis, prognostic information, and appropriate management.

OBJECTIVES

(1) To review the clinical and various pathologic features of renal lesions in systemic lupus erythematosus patients. (2) To introduce the International Society of Nephrology and Renal Pathology Society Classification of Lupus Glomerulonephritis.

DATA SOURCES

A literature review, illustrations with original artwork, and tabulation of clinical and pathologic data of cases obtained from the authors' renal biopsy files examined during the last 8 years were used.

CONCLUSIONS

The International Society of Nephrology/ Renal Pathology Society-sponsored Classification of Lupus Glomerulonephritis proposes standardized definitions of the various pathologic findings, describes clinically relevant lesions, incorporates prognostic parameters, and recommends a uniform way of reporting the renal biopsy findings. Lupus glomerulonephritis is divided into 6 classes primarily based on the morphologic lesions, extent and severity of the involvement, immune complex deposition, and activity and chronicity. Special emphasis is laid on describing qualitative as well as quantitative morphologic data and to include the accompanying tubulointerstitial disease and different vascular lesions, which have prognostic and therapeutic significance. This classification is intended to facilitate a higher degree of reproducibility, resulting in better patient care and more effective future clinical and translational research. Renal biopsy findings in systemic lupus erythematosus add new and independent parameters of prognostic significance to established clinical and genetic factors.

Renal interstitial cells, proteinuria and progression of lupus nephritis: new frontiers for old factors

Interstitial cells, inflammatory-immune cells, tubular cells and endothelial cells of the peritubular capillaries have arisen as possible major players of the nephron damage in lupus nephritis. Increased ICAM-1, Von Willebrand factor, soluble endothelial protein C receptors and decreased ADAMS-13 point to a diffuse vascular damage. Albuminuria elicits a rapid generation of hydrogen peroxide in proximal tubular cells along with nuclear factor-kB activation, endothelin-1 and transforming growth factor (TGF-β1) upregulation. TGF-β1 enhances epithelial-to-mesenchymal transdifferentiation. Albuminuria also enhances the expression of macrophage chemotactic protein-1 and macrophage inflammatory protein-1α, thus leading to increased interstitial inflammation. TGF-β1 and thrombospondin-1, a putative activator of TGF-β, induce apoptosis of peritubular capillaries, as well as of glomerular endothelial cells. All these events can be counteracted by hepatocyte growth factor (HGF), which is expressed by the epithelial tubular cells and stimulates the growth of epithelial cells (mitogen), enhances the motility of epithelial cells (motogen), induces renal epithelial tubule regeneration (morphogen) and enhances angiogenesis (angiogen). The balance between TGF-β1 and HGF could be a key to define the prognostic value of kidney histopathology at baseline and during follow-up, in lupus nephritis. Therapeutic strategies aiming at altering the biological balance in the patients are at hand to test and prove the experimental evidences.

Dual roles of immunoregulatory cytokine TGF-beta in the pathogenesis of autoimmunity-mediated organ damage

Ample evidence suggests a role of TGF-beta in preventing autoimmunity. Multiorgan inflammatory disease, spontaneous activation of self-reactive T cells, and autoantibody production are hallmarks of autoimmune diseases, such as lupus. These features are reminiscent of the immunopathology manifest in TGF-beta1-deficient mice. In this study, we show that lupus-prone (New Zealand Black and White)F(1) mice have reduced expression of TGF-beta1 in lymphoid tissues, and TGF-beta1 or TGF-beta1-producing T cells suppress autoantibody production. In contrast, the expression of TGF-beta1 protein and mRNA and TGF-beta signaling proteins (TGF-beta receptor type II and phosphorylated SMAD3) increases in the target organs, i.e., kidneys, of these mice as they age and develop progressive organ damage. In fact, the levels of TGF-beta1 in kidney tissue and urine correlate with the extent of chronic lesions that represent local tissue fibrosis. In vivo TGF-beta blockade by treatment of these mice with an anti-TGF-beta Ab selectively inhibits chronic fibrotic lesions without affecting autoantibody production and the inflammatory component of tissue injury. Thus, TGF-beta plays a dual, seemingly paradoxical, role in the development of organ damage in multiorgan autoimmune diseases. According to our working model, reduced TGF-beta in immune cells predisposes to immune dysregulation and autoantibody production, which causes tissue inflammation that triggers the production of anti-inflammatory cytokines such as TGF-beta in target organs to counter inflammation. Enhanced TGF-beta in target organs, in turn, can lead to dysregulated tissue repair, progressive fibrogenesis, and eventual end-organ damage.

Stratégies pour faire régresser les lésions de fibrose rénale

The deterioration of renal function in chronic kidney disease is related to the progression of renal fibrosis, which was long considered unavoidable. Today, the reversibility of renal fibrotic lesions is a reality, although still clinically rare. Because angiotensin II is highly profibrotic, blocking its action effectively protects the kidney, as numerous clinical trials have shown. The development of interstitial fibrosis is secondary to the epithelial-to-mesenchymal transition induced by transforming growth factor (TGF)-beta. Bone morphogenic protein-7 (BMP-7) and hepatocyte growth factor (HGF) induce the reverse transition and thus open up perspectives for treatment. Degradation of the extracellular matrix by matrix metalloproteinases or other enzymes is another therapeutic pathway. Renal regeneration may be promoted by modulation of hypoxia-inducible factor-1 (HIF-1) and vascular endothelial growth factor (VEGF).

Leukocytes and the kidney contribute to interstitial inflammation in lupus nephritis

Interstitial leucocyte infiltration, a prominent feature of lupus nephritis, predicts deterioration of renal function. We used two models of lupus nephritis in mice, one with chronic spontaneous disease and the other with acute interferon-alpha (IFN alpha)-mediated disease. The latter is characterized by the virtual absence of interstitial infiltration. In vivo migration assays showed that splenic leukocytes from spontaneously nephritic mice tended to migrate into non-inflamed syngeneic kidneys. This was enhanced if the recipient kidneys were already inflamed. Kidneys from both chronically and acutely nephritic mice showed similar ability to recruit splenic leukocytes from chronically diseased mice. Leukocytes from acutely diseased mice, however, failed to migrate into chronically inflamed kidney. Compared with those with chronic nephritis, the kidneys of acute nephritic mice expressed less of the inflammatory chemokine CXCL13/BLC. Moreover, leukocytes from acute nephritic mice displayed impaired migration, in vitro, to T-cell chemokine attractants. This study links leukocyte infiltration to both kidney chemokine expression, and leukocyte chemotaxis to kidney-expressed chemokines.

Treatment with cyclophosphamide delays the progression of chronic lesions more effectively than does treatment with azathioprine plus methylprednisolone in patients with proliferative lupus nephritis

OBJECTIVE

To analyze the effect of treatment with either pulse cyclophosphamide (CYC) or azathioprine (AZA) combined with methylprednisolone (MP), on serial biopsy results in patients with proliferative lupus nephritis, and to evaluate the predictive value of various histopathologic and clinical parameters with regard to disease outcome.

METHODS

Biopsy specimens from patients with proliferative lupus nephritis, obtained at study entry and after 2 years of therapy, were scored according to a standardized method, and results assessed in relation to disease outcome.

RESULTS

Of the 87 patients originally enrolled, 39 underwent repeat biopsy. These patients were representative of the overall group, both at entry and at 2-year followup. The median activity index changed from 8.0 to 2.7 (no differences between the treatment groups). In the group treated with AZA plus MP (AZA group), the increase in the median chronicity index (from 2.7 to 3.8) was larger than that in the CYC group (from 2.7 to 3.0) (P = 0.050). In multivariate analyses, renal function at enrollment and after 2 years was the best predictor of renal function at the last visit, while none of the histopathologic variables (either at entry or at 2 years) added to this prediction. Comparing patients whose disease transitioned to class II with those who had persistent proliferative lupus nephritis revealed no differences between the treatment groups at either time point, and no clinical differences at 2 years. However, a higher serum creatinine level at entry and greater proteinuria at last visit were characteristic of patients who still had proliferative lupus nephritis at 2 years.

CONCLUSION

These results indicate that, although both CYC and AZA are effective in reducing active lesions in lupus nephritis, progression of chronic lesions is more effectively halted by CYC. Variables assessed by repeat biopsy do not predict clinical outcome.

Bradykinin B2receptor antagonism attenuates inflammation, mast cell infiltration and fibrosis in remote myocardium after infarction in rats

Bradykinin may interfere with myocardial remodelling by promoting inflammation and mast cell activation or, alternatively, by counteracting angiotensin II-dependent collagen accumulation. The aim of the present study was to investigate the role of bradykinin B2 receptor antagonism in inflammatory and mast cell infiltration, fibroplasia and fibrosis accumulation following myocardial infarction (MI). Myocardial infarction was produced by the ligature of the left coronary artery in male Wistar rats that were 10 weeks of age. Immediately after MI, rats received the B2 receptor antagonist Hoe140 (0.5 microg/kg per min, s.c.) or saline over a period of 3 days, 1 week or 4 weeks, constituting three separate groups and their respective controls. Coronal myocardial tissue sections underwent haematoxylin and eosin, Giemsa and picrosirius red staining, as well as immunohistochemistry for alpha-smooth muscle actin (SMA). Morphometric studies were undertaken in three different myocardial regions: MI, remote non-infarcted subendocardium (non-MI SE) and remote non-infarcted interventricular septum (non-MI IVS). The MI size was comparable between Hoe140-treated groups and their respective controls (day 3: 42 +/- 4%, n = 8, vs 43 +/- 3%, n = 6; week 1: 37 +/- 5%, n = 5, vs 39 +/- 2%, n = 5; week 4: 35 +/- 3%, n = 9, vs 36 +/- 3%, n = 7). At day 3, Hoe140 treatment reduced inflammatory cell reaction within the MI (585 +/- 59 vs 995 +/- 170 cells/mm2; P = 0.02), non-MI SE (77 +/- 12 vs 214 +/- 57 cells/mm2; P = 0.02) and non-MI IVS (93 +/- 16 vs 135 +/- 14 cells/mm2; P = 0.03) regions. Mast cells were reduced within the non-MI IVS region (0.8 +/- 0.1 vs 2.5 +/- 0.4 cells/mm2; P = 0.006), but not within the MI region. In non-MI SE, mast cells were rarely found. At week 1, Hoe140 treatment reduced alpha-SMA-positive myofibroblast infiltration within the MI (2535 +/- 383 vs 5636 +/- 968 cells/mm2; P = 0.01) and non-MI SE (222 +/- 33 vs 597 +/- 162 cells/mm2; P = 0.03) regions. In the non-MI IVS region, alpha-SMA-positive myofibroblasts were rarely found. At week 4, Hoe140 treatment reduced collagen volume fraction within the MI (37 +/- 4 vs 53 +/- 4%; P = 0.03), non-MI SE (1.3 +/- 0.2 vs 2.6 +/- 0.3%; P = 0.001) and non-MI IVS (1.1 +/- 0.2 vs 1.8 +/- 0.2%; P = 0.01) regions. Bradykinin promotes inflammation, fibroplasia and fibrosis after MI. Mast cells may have a role in fibrosis deposition through a bradykinin-related mechanism.

Class IV-S versus class IV-G lupus nephritis: clinical and morphologic differences suggesting different pathogenesis

BACKGROUND

A recently proposed reclassification of lupus nephritis divides class IV (diffuse proliferative) lupus nephritis into those cases with predominantly segmental proliferative lesions (class IV-S) and those with predominantly global proliferative lesions (class IV-G). This report explores the validity of this distinction and possible differences in pathogenesis between the 2 types of lesions.

METHODS

Patients from a previously reported series of severe lupus nephritis, with initial biopsies (Bx1) and control biopsies (Bx2) at 6 months after induction therapy were reclassified according to the newly proposed classification. From the original series of 65 patients, 15 patients were reclassified as having class IV-S lesions and 31 patients class IV-G lesions. Clinical data at both biopsies and follow-up were available on all patients selected.

RESULTS

Patients with IV-G lesions had worse proteinuria, lower serum hemoglobins, lower CH50s, and likely higher SCrs (P = .06) and lower C3s (P = .08) than class IV-S patients. Serum CH50 and C3 correlated negatively with severity of class IV-G lesions, but not at all with class IV-S lesions. Patients with class IV-G lesions had greater overall immune deposits and subendothelial deposits on IF and greater hyaline deposits on light microscopy. By contrast, class IV-S showed predominant mesangial deposits and a much higher rate of glomerular fibrinoid necroses (13.3 +/- 15.3% vs. 5.6 +/- 8.0% of viable glomeruli, P = .03). Other distinctions included the fact that membranoproliferative features were found only in class IV-G lesions, and glomerular monocyte/macrophages were much more frequent in this group than in class IV-S lesions (1.77 +/- 0.92 vs. 0.86 +/- 0.77, P = .008). Finally, class IV-G frequently involved all viable glomeruli (74.2% of cases), whereas segmental proliferative lesions never did (P < .0001). Survivals from doubling of SCr at 10 years did not differ between the 2 types at Bx1: 72.5% segmental versus 60.4% global, P= .53. However, among those with persistent lesions at Bx 2 (11 IV-S and 9 IV-G), there was a dramatic difference in 10-year survivals between IV-S lesions (63.6%) and IV-G lesions (0%), P = .08.

CONCLUSION

There are definite clinical and morphologic differences between class IV-S and IV-G lesions. Data suggest that class IV-G lesions behave as an immune complex disease, having positive correlations with extent of immune deposits and negative correlations with serum complement levels, the model traditionally assumed for lupus nephritis as a whole. However, in class IV-S lesions, the presence of proportionally greater glomerular fibrinoid necroses and lack of correlation with extent of immune deposits suggest that these lesions may have a different pathogenesis.

Hepatocyte growth factor and transforming growth factor β1 ratio at baseline can predict early response to cyclophosphamide in systemic lupus erythematosus nephritis

OBJECTIVE

To determine whether the ratio of hepatocyte growth factor (HGF) to transforming growth factor beta1 (TGFbeta1) in systemic lupus erythematosus (SLE) nephritis could be a prognostic factor for response to therapy with cyclophosphamide (CYC) and steroids at 6 months, and to examine whether the molecular ratio of HGF to TGFbeta1 correlates with the activity index (AI) and chronicity index (CI) and has predictive value for remission at the sixth month.

METHODS

Thirty-six SLE patients with new-onset nephritis, 25 of whom were treated with CYC and steroids, entered into a prospective observational cohort trial at a tertiary university referral center. Renal biopsy findings and clinical parameters were recorded for all patients. Histopathologic, clinical, and immunohistochemical data at baseline served to define the predictive value for the outcome at 6 months.

RESULTS

AI and CI at baseline did not distinguish patients who had achieved remission from those who had not achieved remission after receiving CYC plus steroids. HGF and TGFbeta1 were expressed in the tubuli, not in the glomeruli. The CI correlated directly with the TGFbeta1 extension score (TGFbeta1-ES) (r = 0.43, P = 0.008), but correlated indirectly with the HGF intensity score (HGF-IS) (r = -0.39, P = 0.02) and the HGF-ES (r = -0.45, P = 0.006). An HGF-ES:TGFbeta1-ES ratio of >or=1 at baseline distinguished patients who had achieved remission from those who had not achieved remission, with a predictive value of 94%.

CONCLUSION

These findings indicate that baseline expression of renal HGF and TGFbeta1 predicts short-term renal outcome after therapy with CYC and steroids.