Relationship between anti-dsDNA, anti-nucleosome and anti-alpha-actinin antibodies and markers of renal disease in patients with lupus nephritis: a prospective longitudinal study

Introduction  

Glomerulonephritis is a major cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Deposition of autoantibodies in the glomeruli plays a key role in the development of lupus nephritis (LN). Different groups have proposed that either anti-nucleosome antibodies or antibodies that bind the intrinsic renal antigen, α-actinin, are central to the pathogenesis of LN. These theories have been based mainly on cross-sectional studies in patients and on experiments in animal models. No previous longitudinal studies have compared the relationships between levels of these antibodies and markers of renal function. We assessed how well anti-α-actinin, anti-nucleosome and anti-double-stranded DNA (anti-dsDNA) antibodies reflected renal outcome measures in patients with new-onset LN followed for up to 2 years.     

Antiphospholipid antibody profiles in lupus nephritis with glomerular microthrombosis: a prospective study of 124 cases

Introduction  

Glomerular microthrombosis (GMT) is a common vascular change in patients with lupus nephritis (LN). The mechanism underlying GMT is largely unknown. Although several studies have reported the association of antiphospholipid antibodies (aPL) with GMT, the relation between GMT and aPL remains controversial. Previous studies have demonstrated that some aPL could bind to several hemostatic and fibrinolytic proteases that share homologous enzymatic domains. Of the protease-reactive aPL, some can inhibit the anticoagulant activity of activated protein C and the fibrinolytic function of plasmin, and hinder the antithrombin inactivation of thrombin. The purpose of this study was to investigate the prevalence of GMT in LN patients and examine the relation between the aPL profiles (including some protease-reactive aPL) and GMT.     

Mathematical framework for human SLE Nephritis: disease dynamics and urine biomarkers

Background  

Although the prognosis for Lupus Nephritis (LN) has dramatically improved with aggressive immunosuppressive therapies, these drugs carry significant side effects. To improve the effectiveness of these drugs, biomarkers of renal flare cycle could be used to detect the onset, severity, and responsiveness of kidney relapses, and to modify therapy accordingly. However, LN is a complex disease and individual biomarkers have so far not been sufficient to accurately describe disease activity. It has been postulated that biomarkers would be more informative if integrated into a pathogenic-based model of LN.     

Identification of urinary metabolites that distinguish membranous lupus nephritis from proliferative lupus nephritis and focal segmental glomerulosclerosis

Introduction

Systemic lupus erythematosus (SLE or lupus) is a chronic autoimmune disease, and kidney involvement with SLE, a.k.a. lupus nephritis (LN), is a frequent and severe complication of SLE that increases patient morbidity and mortality. About 50% of patients with SLE encounter renal abnormalities which, if left untreated, can lead to end-stage renal disease. Kidney biopsy is considered the criterion standard for diagnosis and staging of LN using the International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification, which was developed to help predict renal outcomes and assist with medical decision-making. However, kidney biopsy-based classification of LN is highly invasive and impractical for real-time monitoring of LN status. Here, nuclear magnetic resonance (NMR) spectroscopy-based metabolic profiling was used to identify urinary metabolites that discriminated between proliferative and pure membranous LN as defined by the ISN/RPS classification, and between LN and primary focal segmental glomerulosclerosis (FSGS).

Methods

Metabolic profiling was conducted using urine samples of patients with proliferative LN without membranous features (Class III/IV; n = 7) or pure membranous LN (Class V; n = 7). Patients with primary FSGS and proteinuria (n = 10) served as disease controls. For each patient, demographic information and clinical data was obtained and a random urine sample collected to measure NMR spectra. Data and sample collection for patients with LN occurred around the time of kidney biopsy. Metabolic profiling analysis was done by visual inspection and principal component analysis.

Results

Urinary citrate levels were 8-fold lower in Class V LN compared to Class III/IV patients, who had normal levels of urinary citrate (P < 0.05). Class III/IV LN patients had > 10-fold lower levels of urinary taurine compared to Class V patients, who had mostly normal levels (P < 0.01). Class V LN patients had normal urinary hippurate levels compared to FSGS patients, who completely lacked urinary hippurate (P < 0.001).

Conclusions

This pilot study indicated differences in urinary metabolites between proliferative LN and pure membranous LN patients, and between LN and FSGS patients. If confirmed in larger studies, these urine metabolites may serve as biomarkers to help discriminate between different classes of LN, and between LN and FSGS.     

Clinicopathologic correlations of renal microthrombosis and inflammatory markers in proliferative lupus nephritis

Introduction

Microthrombosis is often observed in lupus nephritis (LN) lesions, but its clinical significance is unknown. We evaluated the clinicopathologic correlations of renal microthrombosis and inflammatory markers in LN.

Methods

Kidney biopsies from 58 patients with systemic lupus erythematosus (SLE) proliferative nephritis were analyzed with immunohistochemistry (IHC) for intravascular platelet aggregates (CD61), macrophagic infiltration (CD68), and activated complement deposition (C4d). Clinical data at the time of kidney biopsy and follow-up were analyzed with regard to pathologic IHC data.

Results

Microthrombosis was present in 52% of the tissues. It was significantly more prevalent in patients with antiphospholipid antibodies (aPLs) (62% versus 42%). The presence of microthrombosis significantly correlated with higher macrophagic infiltration. Macrophagic infiltration but not microthrombosis was significantly correlated with C4d deposition. Only macrophagic infiltration showed a correlation with SLE and renal activity (proteinuria and active sediment), whereas neither the presence of CD61⁺ microthrombi nor the extent of C4d deposition correlated with LN severity or outcome.

Conclusions

Microthrombosis is associated with higher macrophagic infiltration in LN but does not seem to increase independently the severity of renal damage. Macrophagic infiltration was the best marker of SLE and renal activity in this LN series.     

Preoperative Prediction of Cervical Lymph Node Metastasis Using Primary Tumor SUVmax on 18F-FDG PET/CT in Patients with Papillary Thyroid Carcinoma

Objectives

The aim of the current study was to evaluate the value of preoperative ¹⁸F-FDG (FDG) PET/CT in predicting cervical lymph node (LN) metastasis in patients with papillary thyroid carcinoma (PTC).

Methods

One hundred and ninety-three newly diagnosed PTC patients (M: F = 25:168, age = 46.8 ± 12.2) who had undergone pretreatment FDG PET/CT and had neck node dissection were included in this study. The FDG avidity of the primary tumor and the SUVmax of the primary tumor (pSUVmax) were analyzed for prediction of LN metastasis. Detectability by ultrasonography (US) and FDG PET/CT for cervical LN metastasis were also assessed and compared with the pSUVmax.

Results

The FDG avidity of the primary tumor was identified in 118 patients (FDG avid group: 61.0%, M: F = 16:102, age 47.0 ± 12.7 years) and pSUVmax ranged from 1.3 to 35.6 (median 4.6) in the FDG avid group. The tumor size in the FDG avid group was bigger and there was a higher incidence of LN metastasis compared to the FDG non-avid group (0.93 vs. 0.59 cm, p <0.001 and 49.2 vs. 33.3%, p <0.05). In the FDG avid group, patients with LN metastasis had higher pSUVmax than patients without LN metastasis (8.7 ± 8.3 vs. 5.7 ± 5.1, p <0.001). The incidence of central LN metastasis in patients with a pSUVmax >4.6 was 54%; however, the detectability of central LN metastasis by US and FDG PET/CT were 10.3% and 3.6%, respectively.

Conclusion

A high FDG avidity of the primary tumor was related to LN metastasis in PTC patients. Therefore, patients with a high pSUVmax should be cautiously assessed for LN metastasis and might need a more comprehensive surgical approach.     

Synovial tissues concentrate secreted APRIL

Introduction

TNF-like weak inducer of apoptosis (TWEAK) has been implicated as a mediator of chronic inflammatory processes via prolonged activation of the NF-κB pathway in several tissues, including the kidney. Evidence for the importance of TWEAK in the pathogenesis of lupus nephritis (LN) has been recently introduced. Thus, TWEAK levels may serve as an indication of LN presence and activity.

Methods

Multicenter cohorts of systemic lupus erythematosus (SLE) patients and controls were recruited for cross-sectional and longitudinal analysis of urinary TWEAK (uTWEAK) and/or serum TWEAK (sTWEAK) levels as potential biomarkers of LN. The performance of TWEAK as a biomarker for nephritis was compared with routinely used laboratory tests in lupus patients, including anti-double stranded DNA antibodies and levels of C3 and C4.

Results

uTWEAK levels were significantly higher in LN patients than in non-LN SLE patients and other disease control groups (P = 0.039). Furthermore, uTWEAK was better at distinguishing between LN and non-LN SLE patients than anti-DNA antibodies and complement levels, while high uTWEAK levels predicted LN in SLE patients with an odds ratio of 7.36 (95% confidence interval = 2.25 to 24.07; P = 0.001). uTWEAK levels peaked during LN flares, and were significantly higher during the flare than at 4 and 6 months prior to or following the flare event. A linear mixed-effects model showed a significant association between uTWEAK levels in SLE patients and their disease activity over time (P = 0.008). sTWEAK levels, however, were not found to correlate with the presence of LN or the degree of nephritis activity.

Conclusions

High uTWEAK levels are indicative of LN, as opposed to non-LN SLE and other healthy and disease control populations, and reflect renal disease activity in longitudinal follow-up. Thus, our study further supports a role for TWEAK in the pathogenesis of LN, and provides strong evidence for uTWEAK as a candidate clinical biomarker for LN.     

Urinary TWEAK as a biomarker of lupus nephritis: a multicenter cohort study

Introduction

TNF-like weak inducer of apoptosis (TWEAK) has been implicated as a mediator of chronic inflammatory processes via prolonged activation of the NF-κB pathway in several tissues, including the kidney. Evidence for the importance of TWEAK in the pathogenesis of lupus nephritis (LN) has been recently introduced. Thus, TWEAK levels may serve as an indication of LN presence and activity.

Methods

Multicenter cohorts of systemic lupus erythematosus (SLE) patients and controls were recruited for cross-sectional and longitudinal analysis of urinary TWEAK (uTWEAK) and/or serum TWEAK (sTWEAK) levels as potential biomarkers of LN. The performance of TWEAK as a biomarker for nephritis was compared with routinely used laboratory tests in lupus patients, including anti-double stranded DNA antibodies and levels of C3 and C4.

Results

uTWEAK levels were significantly higher in LN patients than in non-LN SLE patients and other disease control groups (P = 0.039). Furthermore, uTWEAK was better at distinguishing between LN and non-LN SLE patients than anti-DNA antibodies and complement levels, while high uTWEAK levels predicted LN in SLE patients with an odds ratio of 7.36 (95% confidence interval = 2.25 to 24.07; P = 0.001). uTWEAK levels peaked during LN flares, and were significantly higher during the flare than at 4 and 6 months prior to or following the flare event. A linear mixed-effects model showed a significant association between uTWEAK levels in SLE patients and their disease activity over time (P = 0.008). sTWEAK levels, however, were not found to correlate with the presence of LN or the degree of nephritis activity.

Conclusions

High uTWEAK levels are indicative of LN, as opposed to non-LN SLE and other healthy and disease control populations, and reflect renal disease activity in longitudinal follow-up. Thus, our study further supports a role for TWEAK in the pathogenesis of LN, and provides strong evidence for uTWEAK as a candidate clinical biomarker for LN.     

Increased expression of FcγRI/CD64 on circulating monocytes parallels ongoing inflammation and nephritis in lupus

Introduction  

The high-affinity receptor for IgG Fcγ/CD64 is critical for the development of lupus nephritis (LN). Cross-linking Fc receptor on recruited monocytes by IgG-containing immune complexes is a key step in immune-complex-mediated nephritis in systemic lupus erythematosus (SLE). The goal of this study was to determine whether expression of Fc receptor (FcγR) I on circulating monocytes is associated with systemic inflammation and renal disease in SLE patients.     

A Straightforward but Not Piecewise Relationship between Age and Lymph Node Status in Chinese Breast Cancer Patients

Purpose

To investigate the relationship between age and axillary lymph node (LN) involvement in Chinese breast cancer patients, and to replicate a recently identified piecewise relationship between age and LN involvement.

Methods

A dataset, consisting of 3,715 patients (with complete information on study variables) with operable breast cancer consecutively surgically treated between 1996 and 2006, was derived from the database of Shanghai Cancer Hospital. Univariate and multivariate logistic regression were employed to analyze the relationship between age and LN. We subsequently performed a similar analysis on another dataset including 1,832 consecutive patients treated between 2007 and 2008 to replicate our findings in the first dataset.

Results

A U-shaped relationship (previously observed in two European populations) between age and LN status failed to be replicated in our dataset of Chinese patients. Instead, we observed a linear rather than piecewise relationship. After multivariate adjustment, the linear relationship was still present. Moreover, the interaction between age and LN involvement was not modified by tumor size. The odds of LN involvement decreased by 1.5% for each year increase in age (OR 0.985, 95% CI 0.979–0.991, P<0.001). Breast cancer subtypes were also associated with LN status. Proportions of basal-like and ERBB2+ subtypes decreased with increasing age. The observations in the first dataset were successfully replicated in a second independent dataset.

Conclusion

We confirmed a straightforward but not piecewise relationship between age and LN status in Chinese patients. The different pattern between Chinese and European elderly patients should be considered when making clinical decisions.     

Survival of Proper Hepatic Artery Lymph Node Metastasis in Patients with Gastric Cancer: Implications for D2 Lymphadenectomy

Background and Aims

There is a discrepancy between the American Joint Committee on Cancer (AJCC) guidelines (7^th edition) and the Japanese treatment guidelines (3^rd edition) with regard to the extent of D2 lymphadenectomy for gastric cancer. In the AJCC, hepatic artery station (No.12a) lymph node (LN) metastasis is classified as distant metastasis, whereas in the Japanese guidelines, this classified is regional metastasis. This study aimed to evaluate whether it is appropriate to reclassify No.12a LN metastasis as distant metastasis in consideration of survival outcome.

Methods

In this retrospective analysis, data from patients with gastric cancer who underwent regular D2 or greater lymphadenectomy between 1996 and 2006 were evaluated to determine any association between the clinicopathological features of hepatic artery LNs and survival prognosis.

Results

Among the 247 patients with gastric cancer who underwent No.12 LN harvest, 45 (18.2%) were positive for No.12a LN metastasis. No.12a LN metastasis was significantly associated with poor clinicopathological features, advanced tumor stage, and poor overall survival. The 5-year survival rate of patients with No.12a LN metastasis was significantly better than that of patients with distant metastasis (P < 0.05), but was similar to that of patients with LN involvement in the D2 lymphadenectomy region (P > 0.05). No.12a LN metastasis was shown to significantly influence survival outcome in univariate analysis, but was not identified as a significant independent predictor in multivariate analysis. In logistic multivariate regression analysis, T stage, N stage, and station No.3, 5, and 6 LN metastasis were independent predictors of No.12a LN involvement.

Conclusions

It is inappropriate to reclassify No.12a LN metastasis as distant metastasis. We propose that this be considered as regional metastasis and be included in the extent of D2 lymphadenectomy to improve survival outcomes in patients with gastric cancer.     

Vitrification in Open and Closed Carriers at Different Cell Stages: Assessment of Embryo Survival,Development, DNA Integrity and Stability during Vapor Phase Storage for Transport

Background  

High cooling rates with vitrification can be achieved through the use of carriers that allow cryopreservation in fluid volumes < one μl. Open carriers allow direct contact of embryos with liquid nitrogen (LN2) whereas closed carrier systems sequester the embryo within a sealed system during immersion in LN2. The use of closed systems may be preferable to reduce the possibility of cross-contamination. In the present study, we compare open and closed carriers for vitrification of embryos. We also examine their ability to retain embryo viability during vapor phase transport.     

Overall Survival of Stage III Colon Cancer with Only One Lymph Node Metastasis Is Independently Predicted by Preoperative Carcinoembryonic Antigen Level and Lymph Node Sampling Status

Background

This study identified predictors of favorable overall survival (OS) for stage III colon cancer patients who had only one lymph node (LN) metastasis (N1a).

Methods

Variables, including preoperative carcinoembryonic antigen (CEA) level, LN sampling status, and the choices of postoperative adjuvant chemotherapy, were recorded. Prognostic significance was determined using the log-rank test and multivariate Cox regression analysis.

Results

The median 42-month follow-up period included 363 eligible patients. Among them, 230 (63.3%) received only 5-flurouracil (5-FU) adjuvant chemotherapy; 76 (20.9%) underwent oxaliplatin-based regimens; and 57 (15.7%) chose surgery alone. The 5-year survival rate of these evaluated patients was 75%, 63%, and 77%, respectively (P = 0.823). Multivariate analysis revealed that normal preoperative CEA level (≦5 ng/mL) and adequate LN sampling (LN ≧ 12) were significant predictors for higher 5-year OS (P < 0.001; P = 0.007, respectively). However, the use of postoperative adjuvant chemotherapy in these N1a colon cancer patients did not significantly affect their 5-year OS.

Conclusions

A preoperative CEA level of less than or equal to 5 ng/mL, and curative surgery with an adequate lymphadenectomy determined a favorable OS outcome in stage III colon cancer with only one LN metastasis.     

Cytoskeleton reorganization mediates alpha6beta1 integrin-associated actions of laminin on proliferation and survival,but not on steroidogenesis of ovine granulosa cells

Background  

Laminin (LN) is one of the most abundant extracellular matrix components of the basal lamina and granulosa cell layers of ovarian follicles. Culture of ovine granulosa cells (GC) on LN substratum induces cell spreading, enhances cell survival and proliferation, and promotes luteinization. Previous investigations have shown that these effects are mostly mediated by the alpha6beta1 integrin, but its signalization pathways have not been investigated. This study aimed to assess the importance of the cytoskeleton in the alpha6beta1 integrin-mediated actions of laminin on survival, proliferation and steroidogenesis of ovine GC.     

Urine levels of HMGB1 in Systemic Lupus Erythematosus patients with and without renal manifestations

Introduction

Lupus nephritis (LN) is a severe and frequent manifestation of systemic lupus erythematosus (SLE). Its pathogenesis has not been fully elucidated but immune complexes are considered to contribute to the inflammatory pathology in LN. High Mobility Group Box 1 (HMGB1) is a nuclear non-histone protein which is secreted from different types of cells during activation and/or cell death and may act as a pro-inflammatory mediator, alone or as part of DNA-containing immune complexes in SLE. Urinary excretion of HMGB1 might reflect renal inflammatory injury. To assess whether urinary HMGB1 reflects renal inflammation we determined serum levels of HMGB1 simultaneously with its urinary levels in SLE patients with and without LN in comparison to healthy controls (HC). We also analyzed urinary HMGB1 levels in relation with clinical and serological disease activity.

Methods

The study population consisted of 69 SLE patients and 17 HC. Twenty-one patients had biopsy proven active LN, 15 patients had a history of LN without current activity, and 33 patients had non-renal SLE. Serum and urine levels of HMGB1 were both measured by western blotting. Clinical and serological parameters were assessed according to routine procedures. In 17 patients with active LN a parallel analysis was performed on the expression of HMGB1 in renal biopsies.

Results

Serum and urinary levels of HMGB1 were significantly increased in patients with active LN compared to patients without active LN and HC. Similarly, renal tissue of active LN patients showed strong expression of HMGB1 at cytoplasmic and extracellular sites suggesting active release of HMGB1. Serum and urinary levels in patients without active LN were also significantly higher compared to HC. Urinary HMGB1 levels correlated with SLEDAI, and showed a negative correlation with complement C3 and C4.

Conclusion

Levels of HMGB1 in urine of SLE patients, in particular in those with active LN, are increased and correlate with SLEDAI scores. Renal tissue of LN patients shows increased release of nuclear HMGB1 compared to control renal tissue. HMGB1, although at lower levels, is, however, also present in the urine of patients without active LN. These data suggest that urinary HMGB1 might reflect both local renal inflammation as well as systemic inflammation.     

Granulin Exacerbates Lupus Nephritis via Enhancing Macrophage M2b Polarization

Background and Aims

Lupus nephritis (LN), with considerable morbidity and mortality, is one of the most severe manifestations of systemic lupus erythematosus (SLE). Yet, the pathogenic mechanisms of LN have not been clearly elucidated, and efficient therapies are still in great need. Granulin (GRN), a multifunctional protein linked to inflammatory diseases, has recently been reported to correlate with the disease activity of autoimmune diseases. However, the role of GRN in the pathogenic process of LN still remains obscure. In this study, we explored its potential role and underlying mechanism in the pathogenesis of LN.

Methodology/Principal Findings

We found that serum GRN levels were significantly up-regulated and were positively correlated with the severity of LN. Overexpression of GRN in vivo by transgenic injection remarkably exacerbated LN, whereas down-regulation of GRN with shRNA ameliorated LN, firmly demonstrating the critical role of GRN in the pathogenesis of LN. Notably, macrophage phenotype analysis revealed that overexpression of GRN could enhance macrophage polarization to M2b, a key mediator of the initiation and progression of LN. On the contrary, down-regulation of GRN resulted in impaired M2b differentiation, thus ameliorating LN. Moreover, we found that MAPK signals were necessary for the effect of GRN on macrophage M2b polarization.

Conclusion/Significance

We first demonstrated that GRN could aggravate lupus nephritis (LN) via promoting macrophage M2b polarization, which might provide insights into the pathogenesis of LN as well as potential therapeutic strategies against LN.     

Serum Renalase Levels Correlate with Disease Activity in Lupus Nephritis

Introduction

Lupus nephritis (LN) is among the most serious complications of systemic lupus erythematosus (SLE), which causes significant morbidity and mortality. Renalase is a novel, kidney-secreted cytokine-like protein that promotes cell survival. Here, we aimed to investigate the relationship of serum renalase levels with LN and its role in the disease progression of LN.

Methods

For this cross-sectional study, 67 LN patients and 35 healthy controls were enrolled. Seventeen active LN patients who received standard therapies were followed up for six months. Disease activity was determined by the SLE Disease Activity–2000 (SLEDAI-2K) scoring system and serum renalase amounts were determined by ELISA. Predictive value of renalase for disease activity was assessed. Furthermore, the expression of renalase in the kidneys of patients and macrophage infiltration was assessed by immunohistochemistry.

Results

Serum renalase amounts were significantly higher in LN patients than in healthy controls. Moreover, patients with proliferative LN had more elevated serum renalase levels than Class V LN patients. In proliferative LN patients, serum renalase levels were significantly higher in patients with active LN than those with inactive LN. Serum renalase levels were positively correlated with SLEDAI-2K, 24-h urine protein excretion, ds-DNA and ESR but inversely correlated with serum albumin and C3. Renalase amounts decreased significantly after six-months of standard therapy. The performance of renalase as a marker for diagnosis of active LN was 0.906 with a cutoff value of 66.67 μg/ml. We also observed that the amount of renalase was significantly higher in glomerular of proliferative LN along with the co-expression of macrophages.

Conclusion

Serum renalase levels were correlated with disease activity in LN. Serum renalase might serve as a potential indicator for disease activity in LN. The marked increase of glomerular renalase and its association with macrophages suggest that it might play an important role in disease progression of LN.     

Renal expression and serum levels of high mobility group box 1 protein in lupus nephritis

Introduction

High mobility group box 1 protein (HMGB1) is a nuclear DNA binding protein acting as a pro-inflammatory mediator following extracellular release. HMGB1 has been increasingly recognized as a pathogenic mediator in several inflammatory diseases. Elevated serum levels of HMGB1 have been detected in autoimmune diseases including Systemic lupus erythematosus (SLE). However, the local expression of HMGB1 in active lupus nephritis (LN) is not known. Here we aimed to study both tissue expression and serum levels of HMGB1 in LN patients with active disease and after induction therapy.

Methods

Thirty-five patients with active LN were included. Renal biopsies were performed at baseline and after standard induction therapy; corticosteroids combined with immunosuppressive drugs. The biopsies were evaluated according to the World Health Organization (WHO) classification and renal disease activity was estimated using the British Isles lupus assessment group (BILAG) index. Serum levels of HMGB1 were analysed by western blot. HMGB1 expression in renal tissue was assessed by immunohistochemistry at baseline and follow-up biopsies in 25 patients.

Results

Baseline biopsies showed WHO class III, IV or V and all patients had high renal disease activity (BILAG A/B). Follow-up biopsies showed WHO I to II (n = 14), III (n = 6), IV (n = 3) or V (n = 12), and 15/35 patients were regarded as renal responders (BILAG C/D). At baseline HMGB1 was significantly elevated in serum compared to healthy controls (P < 0.0001). In all patients, serum levels decreased only slightly; however, in patients with baseline WHO class IV a significant decrease was observed (P = 0.03). Immunostaining revealed a pronounced extranuclear HMGB1 expression predominantly outlining the glomerular endothelium and in the mesangium. There was no clear difference in HMGB1 expression comparing baseline and follow-up biopsies or any apparent association to histopathological classification or clinical outcome.

Conclusions

Renal tissue expression and serum levels of HMGB1 were increased in LN. The lack of decrease of HMGB1 in serum and tissue after immunosuppressive therapy in the current study may reflect persistent inflammatory activity. This study clearly indicates a role for HMGB1 in LN.     

Bone Disease in Newly Diagnosed Lupus Nephritis Patients

Introduction

Bone loss in Lupus Nephritis (LN) patients is common and multifactorial. The aim of this study was to evaluate the bone status of newly diagnosed LN patients and their correlation with inflammatory factors involved in LN physiopathology.

Methods

We studied 15 pre-menopausal patients with ≤2 months of diagnosed SLE and LN. Patients with prior kidney or bone disease were excluded. In addition to biochemical evaluation (including 25-hydroxyvitamin D₃ [25(OH)D] and Monocyte Chemotactic Protein (MCP1) dosage), we performed bone biopsies followed by osteoblast culture, histomorphometric and immunohistochemistry analysis.

Results

LN patients presented a mean age of 29.5±10 years, a proteinuria of 4.7±2.9 g/day and an estimated glomerular filtration rate (GFR) of 37(31–87) ml/min/1,73 m². They were on glucocorticoid therapy for 34±12 days. All patients presented vitamin D insufficiency (9.9±4.4 ng/ml, range 4–20). Urinary MCP1 correlated negatively with 25(OH)D (r = −0.53, p = 0.003) and positively with serum deoxypyridinoline (r = 0.53, p = 0.004). Osteoblasts isolated from LN bone biopsies presented a significantly higher expression of MCP-1 when compared to controls (32.0.±9.1 vs. 22.9±5.3 mean fluorescence intensities, p = 0.01). LN patients presented a significantly reduced osteoid volume, osteoid thickness, osteoid surface, mineralization surface and bone formation rate, associated with an increased eroded surface and osteoclast surface. Patient’s bone specimens demonstrated a reduced immunostaining for osteoprotegerin (0.61±0.82 vs. 1.08±0.50%, p = 0.003), and an increased expression of Receptor Activator of NF-κB ligand (RANKL) (1.76±0.92 vs. 0.41±0.28%, p<0.001) when compared to controls.

Discussion

Newly diagnosed LN patients presented a significant disturbance in bone metabolism, characterized by an impaired bone formation and mineralization, associated with an increase in resorption parameters. Glucocorticoid use, vitamin D insufficiency and inflammation might be involved in the physiopathology of bone metabolism disturbance.     

Nuclear magnetic resonance-based metabolomics of OCT-embedded frozen kidney samples in mouse and man following standardized pre-analytics

Introduction

Pre-analytical processing significantly affects tissue metabolomes. Since most frozen kidney samples are stored after embedding, standardization of cryoprotective medium removal before metabolomics is essential.

Objectives

We used rodent and human kidney samples to develop an easy and robust pre-analytical procedure compatible with ¹H-nuclear magnetic resonance (NMR)-based metabolomics.

Methods

In mice, renal ischemia was induced for 30 min, followed by 48-h reperfusion (I/R, n?=?6). Right kidneys were transversally cut in two fragments, and snap-frozen in liquid nitrogen (LN2) or in Optimal Cutting Temperature ^® (OCT) fixative. In man, double kidney biopsies were simultaneously obtained before transplantation (n?=?15), and snap-frozen in LN2 or OCT.

Results

¹H-NMR spectrum of pure OCT highlighted two major peaks, i.e. from 3.4 to 4.2 ppm (47.2%) and from 1.2 to 2.2 ppm (42.5%). ¹H-NMR spectra of mouse OCT kidneys were biased at 3.7. By contrast, ¹H-NMR analyses of mouse OCT kidneys iteratively rinsed in saline significantly discriminated sham versus I/R groups, with Q² at 0.695 (to be compared with Q² at 0.866 for LN2 sham vs. I/R kidneys). Discriminant metabolites were analogous in both OCT and LN2 kidneys, with a correlation coefficient of 0.83. In man, iteratively rinsing OCT kidneys in saline eliminated the spectral 3.7-peak, thereby making metabolomes of OCT kidneys interpretable and similar to LN2 samples, with a correlation coefficient of 0.73.

Conclusion

NMR metabolomics using OCT-frozen kidney samples is valuable in mouse and man, following standardized OCT removal. This may help use residual biobanked human tissues to better understand renal pathophysiology.