Julie Belliere

Specific Macrophage Subtypes Influence the Progression of Rhabdomyolysis-Induced Kidney Injury

Rhabdomyolysis can be life threatening if complicated by AKI. Macrophage infiltration has been observed in rat kidneys after glycerol-induced rhabdomyolysis, but the role of macrophages in rhabdomyolysis-induced AKI remains unknown. Here, in a patient diagnosed with rhabdomyolysis, we detected substantial macrophage infiltration in the kidney. In a mouse model of rhabdomyolysis-induced AKI, diverse renal macrophage phenotypes were observed depending on the stage of the disease. Two days after rhabdomyolysis, F4/80(low)CD11b(high)Ly6b(high)CD206(low) kidney macrophages were dominant, whereas by day 8, F4/80(high)CD11b(+)Ly6b(low)CD206(high) cells became the most abundant. Single-cell gene expression analyses of FACS-sorted macrophages revealed that these subpopulations were heterogeneous and that individual cells simultaneously expressed both M1 and M2 markers. Liposomal clodronate-mediated macrophage depletion significantly reduced the early infiltration of F4/80(low)CD11b(high)Ly6b(high)CD206(low) macrophages. Furthermore, transcriptionally regulated targets potentially involved in disease progression, including fibronectin, collagen III, and chemoattractants that were identified via single-cell analysis, were verified as macrophage-dependent in situ. In vitro, myoglobin treatment induced proximal tubular cells to secrete chemoattractants and macrophages to express proinflammatory markers. At day 30, liposomal clodronate-mediated macrophage depletion reduced fibrosis and improved both kidney repair and mouse survival. Seven months after rhabdomyolysis, histologic lesions were still present but were substantially reduced with prior depletion of macrophages. These results suggest an important role for macrophages in rhabdomyolysis-induced AKI progression and advocate the utility of long-term follow-up for patients with this disease.

Shear Stress-Induced Alteration of Epithelial Organization in Human Renal Tubular Cells

Tubular epithelial cells in the kidney are continuously exposed to urinary fluid shear stress (FSS) generated by urine movement and recent in vitro studies suggest that changes of FSS could contribute to kidney injury. However it is unclear whether FSS alters the epithelial characteristics of the renal tubule. Here, we evaluated in vitro and in vivo the influence of FSS on epithelial characteristics of renal proximal tubular cells taking the organization of junctional complexes and the presence of the primary cilium as markers of epithelial phenotype. Human tubular cells (HK-2) were subjected to FSS (0.5 Pa) for 48h. Control cells were maintained under static conditions. Markers of tight junctions (Claudin-2, ZO-1), Par polarity complex (Pard6), adherens junctions (E-Cadherin, β-Catenin) and the primary cilium (α-acetylated Tubulin) were analysed by quantitative PCR, Western blot or immunocytochemistry. In response to FSS, Claudin-2 disappeared and ZO-1 displayed punctuated and discontinuous staining in the plasma membrane. Expression of Pard6 was also decreased. Moreover, E-Cadherin abundance was decreased, while its major repressors Snail1 and Snail2 were overexpressed, and β-Catenin staining was disrupted along the cell periphery. Finally, FSS subjected-cells exhibited disappeared primary cilium. Results were confirmed in vivo in a uninephrectomy (8 months) mouse model where increased FSS induced by adaptive hyperfiltration in remnant kidney was accompanied by both decreased epithelial gene expression including ZO-1, E-cadherin and β-Catenin and disappearance of tubular cilia. In conclusion, these results show that proximal tubular cells lose an important number of their epithelial characteristics after long term exposure to FSS both in vitro and in vivo. Thus, the changes in urinary FSS associated with nephropathies should be considered as potential insults for tubular cells leading to disorganization of the tubular epithelium.

miRNAs in urine: a mirror image of kidney disease?

miRNAs are short non-coding RNAs that control post-transcriptional regulation of gene expression. They are found ubiquitously in tissue and body fluids and participate in the pathogenesis of many diseases. Due to these characteristics and their stability, miRNAs could serve as biomarkers of different pathologies of the kidney. Urine is a non-invasive reservoir of molecules, especially indicative of the urinary system. In this review, we focus on urinary miRNAs and their potential to serve as biomarkers in kidney disease. Past studies show that urinary miRNAs correlate with renal dysfunctions and with processes involved in the pathophysiology. However, these studies also stress the need for future research focusing on large-scale studies to confirm the usability of urinary miRNAs as diagnostic and/or prognostic markers of different kidney diseases in clinical practice.

Calcineurin inhibitor‐sparing regimens based on mycophenolic acid after kidney transplantation

The use of calcineurin inhibitors (CNIs) has dramatically reduced the number of acute rejections and improved kidney allograft survival. However, CNIs can also cause kidney damage and several adverse events. This has prompted transplant physicians to use CNI‐sparing regimens. CNI withdrawal, minimization, or avoidance protocols have been conducted using mycophenolic acid (MPA), and/or mammalian‐target‐of‐rapamycin inhibitors, and/or belatacept. Herein, we review the outcomes of minimizing, withdrawing, or avoiding CNIs when giving mycophenolic acid to de novo and maintenance kidney transplant patients. Protocols on CNI withdrawal, when based on MPA without mammalian‐target‐of‐rapamycin inhibitors (mTORi) or belatacept, in de novo and maintenance kidney transplant patients, are associated with an increased risk of acute rejection. Consequently, these strategies have been abandoned and are not recommended. Protocols on CNI minimization show a beneficial impact of kidney function and acceptable acute rejection rates mainly in patients who have been recipients of a graft for >3–5 years. However, no significant improvement to graft survival has been observed.

Beneficial Effect of Conversion to Belatacept in Kidney-Transplant Patients with a Low Glomerular-Filtration Rate

Belatacept has been found to be efficient at preserving good kidney function in maintenance kidney-transplant patients. Herein, we report on the use of belatacept as a rescue therapy for two kidney-transplant patients presenting with severe adverse events after treatment with calcineurin inhibitors (CNIs) and mammalian target-of-rapamycin (mTOR) inhibitors. Two kidney-transplant patients developed severely impaired kidney function after receiving CNIs. The use of everolimus was associated with severe angioedema. Belatacept was then successfully used to improve kidney function in both cases, even though estimated glomerular-filtration rate before conversion was <20u2009mL/min. These case reports show that belatacept can be used as a rescue therapy, even if kidney function is very low in kidney-transplant patients who cannot tolerate CNIs and/or mTOR inhibitors.

Low- versus high-dose rituximab for antibody-mediated rejection after kidney transplantation

Dear Sir The treatment of antibody-mediated rejection (AMR) after kidney transplantation is based on the association of plasma exchange (PE) with or without rituximab, with or without intravenous immunoglobulins (Iv-Ig) [1–3]. However, if used, the optimal dose of rituximab is still unknown. Furthermore, an increased risk of infection has been reported in kidney-transplant patients receiving rituximab, mainly when combined with polyclonal antibodies [4]. Here, we compared the efficacy and safety of low-dose (375 mg/m2/week for 2 weeks) to high-dose (375 mg/m2/ week for 3–5 weeks, median 4) rituximab given for AMR after kidney transplantation. Between 03/2004 and 01/2011, 39 kidney-transplant patients experienced an AMR, defined by a decreased glomerular filtration rate (GFR), histological features of humoral rejection, positive C4d staining, and the presence of donor-specific antibodies. AMR occurred 46 (1–417) days after transplantation. Initially, high doses of rituximab were given to 22 patients (group I) whereas 17 other patients received later and lower doses of rituximab (group II). Results for 22 of the 39 patients have been previously reported [2]. The patients’ characteristics are presented in Table 1. All patients received steroid pulses (10 mg/kg/day for 3 days), PE, rituximab, as well as Pneumocystis jiroveci and cytomegalovirus prophylaxis for 12 months. Rabbit anti-thymocyte globulins (Thymoglobulin; GenzymeSanofi Lyon, France, 1.25 mg/kg/day for 5 days) or OKT3 (5 mg/day for 5 days) was given to patients who had steroid-resistant cellular and humoral rejection. Before AMR, the proportion of patients receiving tacrolimus was higher in group II; however, after AMR, all patients received tacrolimus, mycophenolic acid, and steroids. The time since the AMR to the last follow-up was significantly longer for patients in group I. At last follow-up, patientand graft-survival rates were similar in both groups, respectively, at 91% and 59% for group I, and 82.3% and 58.8% for group II. Death-censored graft survivals were 68.2% in group I and 70.6% in group II. At the AMR episode, 19% of patients from group I and 56% from group II required dialysis (P = 0.03). In patients not requiring dialysis at diagnosis of AMR, estimated MDRD GFR was 28 (15–56) ml/min in group I and 34 (14– 107) ml/min in group II. At last follow-up, eGFR was 35 (21–58) ml/min in group I and 44 (21–90) ml/min in group II, P = ns. The incidence of a bacterial or viral infection did not differ between groups during the follow-up period, although the incidence of fungal infection was lower in the low-dose rituximab group. Receiving low-dose rituximab (versus receiving high-dose rituximab) was the sole independent protective factor for fungal infection (OR: 0.11, CI95% 0.012–0.986, P = 0.05). Whether rituximab has a beneficial role on treating AMR is still unknown [5], although small series suggest it may have [6]. Here, despite the differences in length of followup and the small number of patients, the outcomes were similar regardless of whether rituximab was used at highor low-dose. However, in the absence of histological data, their impact on chronic AMR is unknown. Less fungal infections occurred in patients receiving low-doses of rituximab.

Transfusion-acquired hepatitis E infection misdiagnosed as severe critical illness polyneuromyopathy in a heart transplant patient

This is the case of a 56‐year‐old man who underwent heart transplantation. Within the first postoperative days, his respiratory and limb muscles weakened, which was attributed to critical illness polyneuromyopathy (CIPM). At day 70 post transplantation, he had increased liver enzyme levels and acute hepatitis E virus (HEV) infection was diagnosed. HEV RNA was found in the serum, stools, and cerebrospinal fluid. Results of further investigations suggested a possible HEV‐related polyradiculoneuropathy. At transplantation, the patient was negative for immunoglobulin (Ig)G, IgM, and HEV RNA. A trace‐back procedure identified the source of infection and concluded that HEV infection was contracted from blood transfusion 12 days prior to transplantation from an HEV RNA‐positive donor. Tests of the organ donor for HEV were negative. Phylogenetic analysis revealed sequence homology between the HEV‐3 strain of the patient and the HEV‐3 strain of the blood donor. Despite ribavirin treatment, the patient died on day 153 post transplantation from multiorgan failure. In conclusion, patients with hepatitis or neuropathic illness who have received blood products should be screened for HEV.

Comparison of the exposure of mycophenolate mofetil and enteric-coated mycophenolate sodium in recipients of kidney-pancreas transplantation

BACKGROUNDnPatients with a simultaneous pancreas-kidney transplant (SPKT), especially those with gastroparesis, often have gastro-intestinal (GI) disorders that can modify immunosuppressant pharmacokinetics. We compared the MPA 12-hours area under the curve (AUC(0-12)) in SKPT patients with severe gastroparesis receiving mycophenolate mofetil (MMF) or enteric-coated mycophenolate sodium (EC-MPS).nnnMATERIAL/METHODSnFifteen SKPT patients having a severe gastroparesis were switched, at 182 (69-1523) days post-transplantation, from MMF to EC-MPS because of GI disorders. MPA AUC(0-12) values were obtained before and after the switch, ie, under MMF (500 mg b.i.d.) at 169 (51-1522) days post-transplantation and EC-MPS (360 mg b.i.d.) at 102 (26-355) days after the switch.nnnRESULTSnMean MPA AUC(0-12) h did not differ significantly under MMF and EC-MPS, ie, 40.13±14 and 38.24±15.5 mg*h/L, respectively. Trough and maximal MPA concentrations were similar with both MPA formulations. Although all patients had GI disorders under MMF (100%), only 3 had persistent GI disorders under EC-MPS (20%) (p<0.001).nnnCONCLUSIONSnIn SKPT patients with severe gastroparesis, exposure to MPA is similar under MMF and EC-MPS. However, the incidence of GI disorders is significantly lower when patients are given EC-MPS.

High tacrolimus intra-patient variability is associated with graft rejection, and de novo donor-specific antibodies occurrence after liver transplantation

AIM To investigate the role of tacrolimus intra-patient variability (IPV) in adult liver-transplant recipients. METHODS We retrospectively assessed tacrolimus variability in a cohort of liver-transplant recipients and analyzed its effect on the occurrence of graft rejection and de novo donor-specific antibodies (dnDSAs), as well as graft survival during the first 2 years posttransplantation. Between 02/08 and 06/2015, 116 patients that received tacrolimus plus mycophenolate mofetil (with or without steroids) were included. RESULTS Twenty-two patients (18.5%) experienced at least one acute-rejection episode (BPAR). Predictive factors for a BPAR were a tacrolimus IPV of > 35% [OR = 3.07 95%CI (1.14-8.24), P = 0.03] or > 40% [OR = 4.16 (1.38-12.50), P = 0.01), and a tacrolimus trough level of < 5 ng/mL [OR=3.68 (1.3-10.4), P =0.014]. Thirteen patients (11.2%) developed at least one dnDSA during the follow-up. Tacrolimus IPV [coded as a continuous variable: OR = 1.1, 95%CI (1.0-1.12), P = 0.006] of > 35% [OR = 4.83, 95%CI (1.39-16.72), P = 0.01] and > 40% [OR = 9.73, 95%CI (2.65-35.76), P = 0.001] were identified as predictors to detect dnDSAs. IPV did not impact on patient- or graft-survival rates during the follow-up. CONCLUSION Tacrolimus-IPV could be a useful tool to identify patients with a greater risk of graft rejection and of developing a de novo DSA after liver transplantation

Complement C5-blocking Agent in Refractory Dermatomyositis

Dermatomyositis (DM) is a rare autoimmune disease that belongs to the group of idiopathic inflammatory myopathies (IIM). The usual treatment of DM was based on steroids, methotrexate, and azathioprine. Intravenous immunoglobulin (IVIG), rituximab (RTX), or other biological treatments recently emerged as steroid-sparing agents.