A Comparison of Pulsatile Hypothermic and Normothermic Ex Vivo Machine Perfusion in a Porcine Kidney Model

BACKGROUND

Hypothermic machine perfusion (HMP) is a well-established method for deceased donor kidney preservation. Normothermic machine perfusion (NMP) might offer similar or greater advantages. We compared the 2 methods in an ex vivo perfusion model using 34 porcine kidneys.

METHODS

Thirty kidneys were stored on ice for 24 h before undergoing 4 h of HMP (n = 15) or NMP (n = 15) followed by 2 h of normothermic ex vivo reperfusion with whole blood. Four kidneys underwent 28 h of cold static storage followed by 2 h of normothermic ex vivo reperfusion. During the 2 h of normothermic ex vivo reperfusion, perfusate flow rates, urinary output, and oxygen consumption rates were compared between all groups.

RESULTS

Porcine kidneys after HMP showed significantly higher urinary output (5.31 ± 2.06 versus 2.44 ± 1.19 mL/min; P = 0.002), oxygen consumption (22.71 ± 6.27 versus 11.83 ± 1.29 mL/min; P = 0.0016), and perfusate flow rates (46.24 ± 12.49 versus 26.16 ± 4.57 mL/min; P = 0.0051) than kidneys after NMP. TUNEL staining of tissue sections showed significantly higher rates of apoptosis in kidneys after NMP (P = 0.027).

CONCLUSIONS

In our study, the direct comparison of HMP and NMP kidney perfusion in a translational model demonstrated superiority of HMP; however, further in vivo studies would be needed to validate those results.

Technical considerations when designing a gene expression panel for renal transplant diagnosis

Gene expression analysis is emerging as a new diagnostic tool in transplant pathology, in particular for the diagnosis of antibody-mediated rejection. Diagnostic gene expression panels are defined on the basis of their pathophysiological relevance, but also need to be tested for their robustness across different preservatives and analysis platforms. The aim of this study is the investigate the effect of tissue sampling and preservation on candidate genes included in a renal transplant diagnostic panel. Using the NanoString platform, we compared the expression of 219 genes in 51 samples, split for formalin-fixation and paraffin-embedding (FFPE) and RNAlater preservation (RNAlater). We found that overall, gene expression significantly correlated between FFPE and RNAlater samples. However, at the individual gene level, 46 of the 219 genes did not correlate across the 51 matched FFPE and RNAlater samples. Comparing gene expression results using NanoString and qRT-PCR for 18 genes in the same pool of RNA (RNAlater), we found a significant correlation in 17/18 genes. Our study indicates that, in samples from the same routine diagnostic renal transplant biopsy procedure split for FFPE and RNAlater, 21% of 219 genes of potential biological significance do not correlate in expression. Whether this is due to fixatives or tissue sampling, selection of gene panels for routine diagnosis should take this information into consideration.

OP0044 WHOLE KIDNEY TRANSCRIPTOMIC ANALYSIS OF FORMALIN-FIXED PARAFFIN-EMBEDDED LUPUS NEPHRITIS KIDNEY BIOPSY TISSUE USING THE NANOSTRING NCOUNTER PLATFORM

Background:

There is an ongoing effort to elucidate the molecular pathways that are key to kidney injury in lupus nephritis (LN). One approach is to study the transcriptome utilising kidney tissue obtained during diagnostic renal biopsy [1]. In clinical practice the most common tissue that is surplus to diagnostic requirements is formalin-fixed paraffin-embedded (FFPE) tissue. However, due to RNA degradation, transcriptomic analysis has been sub-optimal and challenging using standard procedures. The NanoString technology platform has the advantage that reliable detection of transcripts can be achieved even with degraded RNA. In this study we explored the utility of NanoString technology in identifying transcripts in RNA isolated from archival FFPE kidney biopsy sections in a cohort of patients with LN.

Objectives:

To explore the utility of the NanoString platform in elucidating a renal transcriptomic signature in formalin-fixed paraffin-embedded Lupus Nephritis kidney biopsy tissue.

Methods:

We utilised well defined Class III (n=11); Class IV (n=22) and Class V (n=24) LN FFPE kidney biopsies from female patients attending the Imperial College Healthcare NHS Trust. We excluded biopsies with mixed lesions or chronic lesions (i.e. significant glomerular scarring). Kidney biopsies from patients with Thin Basement Membrane (TBM; n=14) disease were used as controls. Six 10 micron thick sections were obtained from each biopsy and RNA isolated using the Qiagen RNeasy FFPE Kit. 100 micrograms of RNA was used for the detection of transcripts. We used the NanoString PanCancer immune profiling panel (770 transcript probes) and an additional 30 custom designed probes, enabling us to detect 800 transcripts, including 40 reference genes. Transcript analysis was performed according to manufacturer’s instructions using the NanoString nSolver software. When analysing differential gene expression (DGE) we used Benjamini-Hochberg adjustment to account for multiple testing. The threshold for statistical significance was an adjusted P value of 0.05 (5% false discovery rate).

Results:

Transcriptomic data passing NanoString nSolver quality control metrics was obtained from all sections. Notably sections included biopsies up to 16 years old (range: 1-16 years). Our transcript panel contained several Type I interferon (IFN) responsive genes, including sialic acid-binding Ig-like lectin 1 (Siglec-1). We detected a type I IFN signature using 8 IFN-responsive transcripts in 39 (68.4%) of the LN biopsies but in none of the TBM biopsies. This signature was present in Class III (n=9, 81.8%), Class IV (n=16, 72.7%) and Class V (n=14, 58.3%) LN samples. When we performed DGE analysis using TBM as the baseline we detected significantly increased expression across the classes (Class III = 202; Class IV = 357 and Class V = 237 differentially expressed transcripts, Figure 1).

Conclusion:

We have successfully identified transcriptomic signatures in RNA samples derived from a relatively large cohort of FFPE LN samples. Consistent with published reports we could detect a type I IFN signature in the LN kidney tissue [1]. Consistent with a recent study [1], we detected increased expression of OPN (osteopontin) and FN1 (fibronectin-1) in proliferative (Class III and IV) but not Class V LN. We are now performing clinical correlations to determine if the differentially expressed transcripts are clinically informative.

References:

[1]Almaani S, Prokopec SD, Zhang J, Yu L, Avila-Casado C, Wither J, Scholey JW, Alberton V, Malvar A, Parikh SV, Boutros PC, Rovin BH, Reich HN. Rethinking Lupus Nephritis Classification on a Molecular Level. J Clin Med. 2019 Sep 23;8(10).

Disclosure of Interests:

Alyssa C. Gilmore: None declared, Hannah Wilson: None declared, Tom Cairns: None declared, Marina Botto: None declared, Liz Lightstone Grant/research support from: Roche - ended 2018, Consultant of: GSK, Aurinia, Pfizer, Achillion, Speakers bureau: Alexion, Ian N. Bruce Grant/research support from: Genzyme Sanofi, GSK, and UCB, Consultant of: Eli Lilly, AstraZeneca, UCB, Iltoo, and Merck Serono, Speakers bureau: UCB, Terry Cook Grant/research support from: Achillion funding for natural history study on C3 glomerulopathy, Consultant of: Scientific consultant to Apellis, Alexion, Achillion, GSK, Speakers bureau: Alexion, Matthew Pickering Grant/research support from: Funding for investigation of therapeutic compounds in pre-clinical models of complement-mediated kidney disease; Achillion funding for natural history study on C3 glomerulopathy, Consultant of: Scientific Advisor for Alexion, Achillion, Apellis

Dual-hormone regulation of psychopathy: Evidence from mass spectrometry

Previous work suggests that testosterone and cortisol interactively predict psychopathy. This effect represents a reversal of the established dual-hormone hypothesis, whereby testosterone is positively correlated with psychopathic traits, but only among individuals with elevated cortisol concentrations. This study aims to replicate the dual-hormone moderation of psychopathy in two independent samples. Enzyme-linked immunoassays (ELISAs) were used to assess cortisol across both samples and testosterone in Sample 1 (n = 165, 100% males). To address recent criticism of ELISAs and potentially extend these findings to women, testosterone concentrations were determined by liquid chromatography tandem mass spectrometry (LC-MS/MS) in Sample 2 (n = 213, 44.1% males). We found conflicting evidence of the dual-hormone moderation of psychopathic traits. Although results were non-significant in Sample 1, a reversal of the dual-hormone hypothesis was found in Sample 2, in which testosterone was positively correlated with psychopathic traits, but only among individuals with high cortisol. This replication provides mixed support for less common reversals to the dual-hormone hypothesis. These findings emphasize the importance of using LC-MS/MS to measure testosterone and adds to the growing body of work on the relationship between hormones and psychopathology in general.

Protocol and rationale for the first South Asian 5-year prospective longitudinal observational cohort study and biomarker evaluation investigating the clinical course and risk profile of IgA nephropathy: GRACE IgANI cohort

Background: IgA nephropathy (IgAN) is the most common primary glomerulonephritis and an important cause of end-stage kidney disease. Unlike the slowly progressive course seen among Caucasian and East Asian subjects (actuarial survival 80-85% over 10 years), in India about 30-40% of patients have nephrotic syndrome and renal dysfunction at presentation and a 10-year renal survival of 35%, as reported from a retrospective registry. These observations cannot be entirely attributed to a lack of uniform screening protocols or late referral and attest to the probability that IgAN may not be the same disease in different parts of the world. Methods: We will prospectively recruit 200 patients with IgAN (the GRACE IgANI- Glomerular Research And Clinical Experiments- Ig A Nephropathy in Indians-cohort) and stratify them into low and high risk of progression based on published absolute renal risk scores. We will test the validity of this risk score in an unselected Indian IgAN population over a 5-year follow-up period. In parallel, we will undertake extensive exploratory serum, urine, renal and microbiome biomarker studies, firstly, to determine if the underlying pathogenic pathways are the same in Indian IgAN compared to those reported in Caucasian and East Asian IgAN. Secondly, we will systematically assess the value of measuring selected biomarkers and adding this data to traditional measures of risk in IgAN to predict kidney failure. We ultimately hope to generate a composite IgAN risk score specific for the Indian population. Ethics and data dissemination: Approval was obtained from the Institutional Review Board (Silver, Research and Ethics Committee) of the Christian Medical College, Vellore, India (Ref. No. IRB Min. No. 8962 [Other] dated 23.07.2014 and IRB Min. No. 9481 [Other] dated 24.06.2015). It is anticipated that results of this study will be presented at national and international meetings, with reports being published from late 2018.

Tonsillectomy in a European Cohort of 1,147 Patients with IgA Nephropathy

BACKGROUND

Tonsillectomy has been considered a treatment for IgA nephropathy (IgAN). It is aimed at removing a source of pathogens, reducing mucosa-associated lymphoid tissue and decreasing polymeric IgA synthesis. However, its beneficial effect is still controversial. In Asia, favorable outcomes have been claimed mostly in association with corticosteroids. In Europe, small, single-center uncontrolled studies have failed to show benefits.

METHODS

The European validation study of the Oxford classification of IgAN (VALIGA) collected data from 1,147 patients with IgAN over a follow-up of 4.7 years. We investigated the outcome of progression to end-stage renal disease (ESRD) and/or 50% loss of estimated glomerular filtration rate (eGFR) and the annual loss of eGFR in 61 patients who had had tonsillectomy.

RESULTS

Using the propensity score, which is a logistic regression model, we paired 41 patients with tonsillectomy and 41 without tonsillectomy with similar risk of progression (gender, age, race, mean blood pressure, proteinuria, eGFR at renal biopsy, previous treatments and Oxford MEST scores). No significant difference was found in the outcome. Moreover, we performed an additional propensity score pairing 17 patients who underwent tonsillectomy after the diagnosis of IgAN and 51 without tonsillectomy with similar risk of progression at renal biopsy and subsequent treatments. No significant difference was found in changes in proteinuria, or in the renal end point of 50% reduction in GFR and/or ESRD, or in the annual loss of eGFR.

CONCLUSION

In the large VALIGA cohort of European subjects with IgAN, no significant correlation was found between tonsillectomy and renal function decline.

Local IL-17 Production Exerts a Protective Role in Murine Experimental Glomerulonephritis

IL-17 is a pro-inflammatory cytokine implicated in the pathogenesis of glomerulonephritis and IL-17 deficient mice are protected from nephrotoxic nephritis. However, a regulatory role for IL-17 has recently emerged. We describe a novel protective function for IL-17 in the kidney. Bone marrow chimeras were created using wild-type and IL-17 deficient mice and nephrotoxic nephritis was induced. IL-17 deficient hosts transplanted with wild-type bone marrow had worse disease by all indices compared to wild-type to wild-type bone marrow transplants (serum urea p<0.05; glomerular thrombosis p<0.05; tubular damage p<0.01), suggesting that in wild-type mice, IL-17 production by renal cells resistant to radiation is protective. IL-17 deficient mice transplanted with wild-type bone marrow also had a comparatively altered renal phenotype, with significant differences in renal cytokines (IL-10 p<0.01; IL-1β p<0.001; IL-23 p<0.01), and macrophage phenotype (expression of mannose receptor p<0.05; inducible nitric oxide synthase p<0.001). Finally we show that renal mast cells are resistant to radiation and produce IL-17, suggesting they are potential local mediators of disease protection. This is a novel role for intrinsic cells in the kidney that are radio-resistant and produce IL-17 to mediate protection in nephrotoxic nephritis. This has clinical significance as IL-17 blockade is being trialled as a therapeutic strategy in some autoimmune diseases.

Long-term outcome of anti-neutrophil cytoplasm antibody-associated glomerulonephritis: evaluation of the international histological classification and other prognostic factors

BACKGROUND

Anti-neutrophil cytoplasm antibody (ANCA) associated vasculitis with renal involvement requires treatment with potentially toxic drugs to reduce morbidity and mortality, and there is a major challenge to determine clinical and histological features predictive of renal prognosis. The aim of our study was to evaluate the use of the 2010 international histological classification for ANCA-associated glomerulonephritis (AAGN) as a predictor of renal outcome when used in conjunction with other prognostic factors.

METHODS

One hundred and four patients with AAGN treated at our centre were included: 23 were classified as focal, 26 as crescentic, 48 as mixed and 7 as sclerotic. Renal outcomes were based on estimated glomerular filtration rate (eGFR) at 1 and 5 years, and on renal survival.

RESULTS

By univariate analysis, patients in the focal class had the best renal outcome, those in the sclerotic class the worst outcome, and those in the mixed and crescentic classes had intermediate renal survival. There was no significant difference in outcome between the mixed and crescentic classes. In multivariate models, histological class did not improve model fit or associate with renal outcome after adjusting for established prognostic factors. Lower percentage of normal glomeruli, greater degree of tubular atrophy (TA), MPO-ANCA positivity, increasing age and lower starting eGFR, all correlated with poorer renal outcomes.

CONCLUSIONS

We conclude that, in our cohort of patients, the international histological classification is predictive of renal outcome in AAGN, but did not appear to be additionally informative over other established prognostic factors in multivariate analysis. However, it may be of value to combine the current histological classification with other established parameters, such as TA and percentage normal glomeruli.

Recognizing isolated IgG4-related nephropathy

IgG4-related tubulointerstitial nephritis is an uncommon cause of renal impairment. It has been associated with dysfunction in a number of other organs giving rise to the term IgG4-related systemic disease; organ involvement can occur metachronously, hence, making it more difficult to identify patients. The exact cause of this condition remains unknown. Here, we present a case of isolated renal involvement which demonstrates how particular biochemical, radiological and histopathological changes should raise the suspicion of IgG4-related nephropathy, especially when there is an absence of clues from any other organ.

Survival and growth of chestnut backcross seeds and seedlings on surface mines

Some scientists consider the loss of the American chestnut from forests in the eastern United States as one of the greatest forest ecological disasters in the 20th century. The American Chestnut Foundation has been attempting to restore chestnut by backcrossing blight-resistant Chinese chestnut to American chestnut and selecting those strains with blight resistance. Third-generation backcross seeds and seedlings have been produced and planted by researchers. Surface-mined lands provide a land base where these backcross chestnut seedlings may be introduced back into forests. In 2008, seeds of two parent species of chestnut (100% American and 100% Chinese) and three breeding generations (BF, BF, and BF backcrosses) were planted into loosely graded mine soils with and without tree shelters. First-year establishment from seeds averaged 81%. After the fourth year, survival without shelters declined for all chestnut stock types except for Chinese (80%): American 40%, BF 70%, BF 40%, and BF 55%. Survival with shelters was only slightly better after the fourth year (average, 60% with shelters and 57% without). Height growth was not different among stock types, and average height after the fourth year was 43 cm without shelters and 56 cm with shelters. In 2009, seeds and seedlings of the same chestnut stock types were planted into brown (pH 4.5) or gray (pH 6.6) mine soils. Only six out of 250 seeds germinated, which was very poor considering 81% average seed germination in 2008. Transplanted chestnut seedling survival was much better. After the third year, seedling survival was 85% in brown and 80% in gray soil, but significant differences were found with stock types. Survival was significantly higher with American, Chinese, and BF stock types (75%) than with BF and BF (60%). Height after the third season averaged 90 cm on brown and 62 cm on gray soil. Chestnut backcrosses displayed no hybrid vigor and were not better in survival and growth than the parent stock. All five stock types grew on mine soils in West Virginia, and we found surface mines to be promising sites for introducing blight-resistant chestnut backcross trees into the Appalachian forest.

Adenocarcinoma of the seminal vesicles complicated by antineutrophil cytoplasmic antibody vasculitis: a case report and review of the literature

Introduction

Adenocarcinoma of the seminal vesicles is a very rare malignancy, with less than 100 cases reported worldwide. It is documented to have a poor prognosis, with the majority of patients developing metastatic disease, most commonly in the prostate, bladder and rectum. Currently there is no standard treatment for metastatic disease and the limited reports of treatment with radiotherapy, chemotherapy and hormonal (anti-androgenic) therapy show that they are generally of modest benefit. The association between malignancy and an increased risk of autoimmune vasculitis has been demonstrated in a number of malignancies, but to date there have been no documented cases of adenocarcinoma of the seminal vesicles associated with anti-neutrophil cytoplasmic antibody vasculitis.

Case presentation

In this report we describe the case of a 55-year-old Caucasian man with metastatic adenocarcinoma of the seminal vesicles. He previously had received chemotherapy treatment for advanced testicular cancer and later presented with hemospermia. He subsequently developed c-antineutrophil cytoplasmic antibody vasculitis requiring intensive immunosuppression and renal dialysis.

Conclusion

Adenocarcinoma of the seminal vesicles is a rare diagnosis and our case is more unusual in that our patient previously had chemotherapy treatment for advanced testicular cancer and went on to develop severe antineutrophil cytoplasmic antibody vasculitis when diagnosed with metastatic seminal vesicle cancer. This case illustrates that autoimmune vasculitis can occur in any patient with malignancy and an early referral to the renal team combined with renal biopsy can assist in the earlier diagnosis and more successful management of these rare events. This case should be of interest to oncologists, renal physicians, urologists and general physicians who encounter patients presenting with hemospermia or vasculitis.

Loss of properdin exacerbates C3 glomerulopathy resulting from factor H deficiency

Complement factor H (CFH) is a negative regulator of the alternative pathway of complement, and properdin is the sole positive regulator. CFH-deficient mice (CFH(-/-)) develop uncontrolled C3 activation and spontaneous renal disease characterized by accumulation of C3 along the glomerular basement membrane, but the role of properdin in the pathophysiology is unknown. Here, we studied mice deficient in both CFH and properdin (CFH(-/-).P(-/-)). Although CFH(-/-) mice had plasma depleted of both C3 and C5, CFH(-/-).P(-/-) animals exhibited depletion of C3 predominantly, recapitulating the plasma complement profile observed in humans with properdin-independent C3 nephritic factors. Glomerular inflammation, thickening of the capillary wall, and glomerular C3 staining were significantly increased in CFH(-/-).P(-/-) compared with CFH(-/-) mice. We previously reported that exogenous CFH ameliorates C3 staining of the glomerular basement membrane and triggers the appearance of mesangial C3 deposits in CFH(-/-) mice; here, we show that these effects require properdin. In summary, during uncontrolled activation of C3 driven by complete CFH deficiency, properdin influences the intraglomerular localization of C3, suggesting that therapeutic inhibition of properdin would be detrimental in this setting.

Hyperglycemia causes renal cell damage via CCN2-induced activation of the TrkA receptor: implications for diabetic nephropathy

CCN2, a secreted profibrotic protein, is highly expressed in diabetic nephropathy (DN) and implicated in its pathogenesis; however, the actions of CCN2 in DN remain elusive. We previously demonstrated that CCN2 triggers signaling via tropomyosin receptor kinase A (TrkA). Trace expression of TrkA is found in normal kidneys, but its expression is elevated in several nephropathies; yet its role in DN is unexplored. In this study we show de novo expression of TrkA in human and murine DN. We go on to study the molecular mechanisms leading to TrkA activation and show that it involves hypoxia, as demonstrated by ischemia-reperfusion injury and in vitro experiments mimicking hypoxia, implicating hypoxia as a common pathway leading to disease. We also expose renal cells to hyperglycemia, which led to TrkA phosphorylation in mesangial cells, tubular epithelial cells, and podocytes but not in glomerular endothelial cells and renal fibroblasts. In addition, we report that hyperglycemia caused an induction of phosphorylated extracellular signal-related kinase 1/2 and Snail1 that was abrogated by silencing of TrkA or CCN2 using small interfering RNA. In conclusion, we provide novel evidence that TrkA is activated in diabetic kidneys and suggest that anti-TrkA therapy may prove beneficial in DN.