Glomerular number (N_g) is considered a major determinant of renal function and outcome. In the dog, it has been shown that Ng can be estimated with reasonable precision in vivo by means of a renal biopsy and magnetic resonance imaging (MRI). Thus, this method was applied to study anatomoclinical correlations in stable human renal transplants. Thirty-nine stable renal transplants were included. A protocol renal allograft biopsy was done at 4 mo. Biopsies were evaluated according to Banff criteria. Glomerular volume fraction (Vv_glom/cortex) was measured by means of a point-counting method, and mean glomerular volume (V_g) was estimated by means of Weibel and Gomez (V_g-W&G) and maximal profile area (V_g-MPA) methods. MRI was used to estimate renal cortical volume (V_cortex). N_g was calculated as (Vv_glom/cortex × V_cortex)/V_g. GFR was estimated by the inulin clearance. Ten age-matched donor biopsies served as controls for V_g. Histologic diagnosis was as follows: normal (n = 20), borderline (n = 7), acute rejection (n = 1), and chronic allograft nephropathy (n = 11). Vv_glom/cortex was 3.4 ± 1.1%, V_cortex was 167 ± 46 cm³, V_g-W&G was 3.2 ± 1.2 × 10⁶ μm³, and V_g-MPA was 3.3 ± 1.0 × 10⁶ μm³. V_g-W&G in donor and recipient biopsies was not different (3.6 ± 1.1 versus 3.2 ± 1.2 × 10⁶ μm³). Total glomerular number estimated by means of V_g-W&G (N_g-W&G) was 0.73 ± 0.33 × 10⁶ and by V_g-MPA (N_g-MPA) was 0.74 ± 0.31 × 10⁶. A positive correlation between GFR and N_g-W&G (r = 0.47, P = 0.002) was observed. Furthermore, the older the donor, the higher V_g-W&G (r = 0.37, P = 0.01) and the lower N_g-W&G (r = −0.40, P = 0.01). Total glomerular number can be estimated in stable renal allografts by means of a renal biopsy and MRI. Our data show that N_g depends on donor age and positively correlates with GFR. E-mail: 28383xfo@comb.es

Calprotectin is produced by neutrophils and macrophages, and released during the acute phase of the ANCA vasculitis. The aim of our study was to determine if serum and urine calprotectin are disease activity and prognosis biomarkers in ANCA vasculitis patients during remission. Forty-two ANCA vasculitis patients were included. Twenty-seven patients were in remission phase under immunosuppressive therapy, and 15 patients were in the acute phase. Four healthy controls were included. We determined calprotectin in serum and urine samples at the time of the inclusion. We recorded the incidence of relapse and the evolution of GFR, proteinuria, hematuria, and C reactive protein and ANCA titer during 24 months of follow-up. In remission phase, serum calprotectin was higher than in healthy controls but lower compared to acute patients (p = 0.05). Serum calprotectin at inclusion was higher in patients who increased proteinuria during follow-up (p = 0.04), with hematuria (p = 0.08), and with non-decreasing ANCA titer (p = 0.0019). Serum calprotectin at inclusion in stable patients who subsequently decreased GFR during follow-up was higher compared with those with a stable or improving GFR (p = 0.03). Urine calprotectin was lower in patients with sclerotic histology in remission (p = 0.03) and acute phase (p = 0.12) compared to the rest of histologies. Worsening of renal function, hematuria, rising proteinuria and non-decreasing ANCA correlated with higher levels of serum calprotectin at recruitment. Low urine calprotectin was found in patients with sclerotic histology. Calprotectin during remission in ANCA vasculitis may be useful to identify subclinical inflammation and worse renal prognosis patients.

The inflammasome is an immune multiprotein complex that activates pro-caspase 1 in response to inflammation-inducing stimuli and it leads to IL-1β and IL-18 proinflammatory cytokine production. NLRP1 and NLRP3 inflammasomes are the best characterized and they have been related to several autoimmune diseases. It is well known that the kidney expresses inflammasome genes, which can influence the development of some glomerulonephritis, such as lupus nephritis, ANCA glomerulonephritis, IgA nephropathy and anti-GBM nephropathy. Polymorphisms of these genes have also been described to play a role in autoimmune and kidney diseases. In this review, we describe the main characteristics, activation mechanisms, regulation and functions of the different inflammasomes. Moreover, we discuss the latest findings about the role of the inflammasome in several glomerulonephritis from three different points of view: in vitro, animal and human studies.

Acute tubulointerstitial nephritis (ATIN) is an immunomediated cause of acute kidney injury. The prevalence of ATIN among the causes of acute kidney injury (AKI) is not negligible, especially those cases related to certain drugs. To date, there is a lack of reliable non-invasive diagnostic and follow-up markers. The gold standard for diagnosis is kidney biopsy, which shows a pattern of tubulointerstitial leukocyte infiltrate. The urinalysis findings can aid in the diagnosis but are no longer considered sensitive or specific. Atthe present time, there is a rising attentiveness tofinding trustworthy biomarkers of the disease, with special focus in urinary cytokines and chemokines that may reflect kidney local inflammation. Cell-based tests are of notable interest to identify the exact drug involved in hypersensitivity reactions to drugs, manifesting as ATIN. Certain single-nucleotide polymorphisms in HLA or cytokine genes may confer susceptibility to the disease according to pathophysiological basis. In this review, we aim to critically examine and summarize the available evidence on this topic.

Background: Acute tubulointerstitial nephritis (ATIN) diagnosis lays on histological assessment through a kidney biopsy, given the absence of accurate non-invasive biomarkers. The aim of this study was to evaluate the accuracy of different urinary inflammation-related cytokines for the diagnostic of ATIN and its distinction from acute tubular necrosis (ATN). Methods: We included 33 patients (ATIN (n = 21), ATN (n = 12)), and 6 healthy controls (HC). We determined the urinary levels of 10 inflammation-related cytokines using a multiplex bead-based Luminex assay at the time of biopsy and after therapy, and registered main clinical, analytical and histological data. Results: At the time of biopsy, urinary levels of I-TAC/CXCL11, CXCL10, IL-6, TNFα and MCP-1 were significantly higher in ATIN compared to HC. A positive correlation between the extent of the tubulointerstitial cellular infiltrates in kidney biopsies and the urinary concentration of I-TAC/CXCL11, MIG/CXCL9, CXCL10, IL17, IFNα, MCP1 and EGF was observed. Notably, I-TAC/CXCL11, IL-6 and MCP-1 were significantly higher in ATIN than in ATN, with I-TAC/CXCL11 as the best discriminative classifier AUC (0.77, 95% CI 0.57–0.95, p = 0.02). A combinatory model of these three urinary cytokines increased the accuracy in the distinction of ATIN/ATN compared to the individual biomarkers. The best model resulted when combining the three cytokines with blood eosinophil and urinary leukocyte counts (LR = 9.76). Follow-up samples from 11ATIN patients showed a significant decrease in I-TAC/CXCL11, MIG/CXCL9 and CXCL10 levels. Conclusions: Urinary I-TAC/CXCL11, CXCL10, IL6 and MCP-1 levels accurately distinguish patients developing ATIN from ATN and healthy individuals and may serve as novel non-invasive biomarkers in this disease.

The use of combination antiretroviral therapy has led to dramatic improvements in the life expectancy of HIV-infected persons. As result, the HIV population is aging and increasingly facing illnesses typically seen in the elderly, such as chronic kidney disease (CKD). A retrospective longitudinal study was conducted using data from years 2010 and 2014 in all HIV-infected persons enrolled at the Spanish VACH cohort. We analyzed the prevalence and the predictive factors for developing CKD (estimated glomerular filtration rate, eGFR<60mL/min/1.73m²). The CKD prevalence at baseline was 456/8968, 5.1% [4.6-5.6%]. Of 8512 HIV-positive individuals examined without CKD at baseline (73.7% male, median age 44 years-old), 2.15% developed CKD (eGFR<60mL/min/1.73m²). The odds ratios [95%CI] for the independent predictive factors identified were gender (male) 0.54 [0.39-0.75], age (per year) 1.08 [1.07-1.10], AIDS diagnosis 1.40 [1.03-1.91], protease inhibitor-based regimens 1.49 [1.10-2.02], hypertension 1.37 [0.94-1.99], diabetes 1.84 [1.33-2.55] and history of cardiovascular events 1.66 [0.96-2.86]. The prevalence and risk factors for CKD and its progression are high in the VACH cohort. Thus, preventive measures such as control of hypertension, diabetes and obesity, as well as efforts for avoiding exposure to nephrotoxic drugs, including some antiretrovirals, are warranted in this aging HIV population.