An ontology-based approach for modelling and querying Alzheimer's disease data.

BACKGROUND: The recent advances in biotechnology and computer science have led to an ever-increasing availability of public biomedical data distributed in large databases worldwide. However, these data collections are far from being "standardized" so to be harmonized or even integrated, making it impossible to fully exploit the latest machine learning technologies for the analysis of data themselves. Hence, facing this huge flow of biomedical data is a challenging task for researchers and clinicians due to their complexity and high heterogeneity. This is the case of neurodegenerative diseases and the Alzheimer's Disease (AD) in whose context specialized data collections such as the one by the Alzheimer's Disease Neuroimaging Initiative (ADNI) are maintained. METHODS: Ontologies are controlled vocabularies that allow the semantics of data and their relationships in a given domain to be represented. They are often exploited to aid knowledge and data management in healthcare research. Computational Ontologies are the result of the combination of data management systems and traditional ontologies. Our approach is i) to define a computational ontology representing a logic-based formal conceptual model of the ADNI data collection and ii) to provide a means for populating the ontology with the actual data in the Alzheimer Disease Neuroimaging Initiative (ADNI). These two components make it possible to semantically query the ADNI database in order to support data extraction in a more intuitive manner. RESULTS: We developed: i) a detailed computational ontology for clinical multimodal datasets from the ADNI repository in order to simplify the access to these data; ii) a means for populating this ontology with the actual ADNI data. Such computational ontology immediately makes it possible to facilitate complex queries to the ADNI files, obtaining new diagnostic knowledge about Alzheimer's disease. CONCLUSIONS: The proposed ontology will improve the access to the ADNI dataset, allowing queries to extract multivariate datasets to perform multidimensional and longitudinal statistical analyses. Moreover, the proposed ontology can be a candidate for supporting the design and implementation of new information systems for the collection and management of AD data and metadata, and for being a reference point for harmonizing or integrating data residing in different sources.

1,25 Dihydroxyvitamin D circulating levels, calcitriol administration, and incidence of acute rejection, CMV infection, and polyoma virus infection in renal transplant recipients.

Observation that 1,25-Dihydroxyvitamin-D3 has an immunomodulatory effect on innate and adaptive immunity raises the possible effect on clinical graft outcome. Aim of this study was to evaluate the correlation of biopsy-proven acute rejection, CMV infection, BKV infection, with 1,25-Dihydroxyvitamin-D3 deficiency and the benefit of calcitriol supplementation before and during the transplantation. Risk factors and kidney graft function were also evaluated. All RTRs received induction therapy with basiliximab, cyclosporine, mycophenolic acid, and steroids. During the first year, the incidence of BPAR (4% vs 11%, P=.04), CMV infection (3% vs 9%, P=.04), and BKV infection (6% vs 19%, P=.04) was significantly lower in users compared to controls. By multivariate Cox regression analysis, 1,25-Dihydroxyvitamin-D3 deficiency and no calcitriol exposure were independent risk factors for BPAR (HR=4.30, P<.005 and HR=3.25, P<.05), for CMV infection (HR=2.33, P<.05 and HR=2.31, P=.001), and for BKV infection (HR=2.41, P<.05 and HR=2.45, P=.001). After one year, users had a better renal function: eGFR was 62.5±6.7 mL/min vs 51.4±7.6 mL/min (P<.05). Only one user developed polyomavirus-associated nephropathy vs 15 controls. Two users lost their graft vs 11 controls. 1,25(OH)2-D3 deficiency circulating levels increased the risk of BPAR, CMV infection, BKV infection after kidney transplantation. Administration of calcitriol is a way to obtain adequate 1,25(OH)2-D3 circulating levels.

Everolimus leads to a lower risk of BKV viremia than mycophenolic acid in de novo renal transplantation patients: a single-center experience.

BACKGROUND: There are limited published data concerning the effects of different immunosuppressive regimens on the development of polyomavirus (BKV) viremia. We examined the risk of developing BKV viremia in kidney transplant recipients receiving everolimus (EVR) or mycophenolic acid (MPA) as maintenance therapy. METHODS: We observationally analyzed 296 patients who underwent renal transplantation at our center between 2005 and 2010: 58 were treated with EVR and low-dose cyclosporine (LD-CyA) (group 1) and 238 with MPA and standard-dose CyA (group 2). All of the patients received induction therapy with basiliximab and maintenance steroids. BKV viremia (a whole-blood viral load of >850 copies/mL) was measured by means of real-time polymerase chain reaction at least once a month during a 12-month follow-up period. RESULTS: BKV viremia was detected in 57 patients (19%), five (9%) in group 1 and 52 (22%) in group 2. Kaplan-Meier analyses showed that freedom from BKV viremia was significantly more frequent in group 1. The mean time of onset of BKV viremia was about four months after transplantation in both groups. The median viral load was greater in group 2 (12.5 ± 6.1 vs. 2.5 ± 1.8 × 10(4) copies/mL; p = 0.01). After the onset of BKV viremia, graft function significantly declined in group 2: 11 patients developed polyomavirus-associated nephropathy (PVAN) and four presumptive PVAN; nine experienced an acute rejection after the discontinuation of MPA, and 11 (21%) lost their graft. There was no graft loss in group 1. CONCLUSION: These findings suggest that in comparison with MPA and Cya, an EVR and LD-CyA regimen lowers the risk of BKV viremia after kidney transplantation and favorably alters outcomes.

De novo collapsing glomerulopathy after kidney transplantation: Description of two cases.

BACKGROUND: Among different forms of de novo focal segmental glomerulosclerosis (FSGS), which can develop after kidney transplantation (KTx), collapsing glomerulopathy (CG) is the least frequent variant, but it is associated with the most severe form of nephrotic syndrome, histological findings of important vascular damage, and a 50% risk of graft loss. Here, we report two cases of de novo post-transplant CG. CLINICAL PRESENTATION: A 64-year-old White man developed proteinuria and worsening of renal function 5 years after KTx. Before the KTx, the patient was affected by an uncontrolled resistant hypertension, despite multiple antihypertensive therapies. Blood levels of calcineurin inhibitors (CNIs) were stable, with intermittent peaks. Kidney biopsy showed the presence of CG. After introduction of angiotensin receptor blockers (ARBs), urinary protein excretion progressively decreased in 6 months, but subsequent follow-up confirmed a progressive renal function decline. A 61-year-old White man developed CG 22 years after KTx. In his medical history, he was hospitalized twice to manage uncontrolled hypertensive crises. In the past, basal serum cyclosporin A levels were often detected above the therapeutic range. Low doses of intravenous methylprednisolone were administered due to the histological inflammatory signs shown on renal biopsy, followed by a rituximab infusion as a rescue therapy, but no clinical improvement was seen. DISCUSSION AND CONCLUSION: These two cases of de novo post-transplant CG were supposed to be mainly caused by the synergic effect of metabolic factors and CNI nephrotoxicity. Identifying the etiological factors potentially responsible for de novo CG development is essential for an early therapeutic intervention and the hope of better graft and overall survival.

Thrombotic microangiopathy induced by interferon beta in patients with multiple sclerosis: three cases treated with eculizumab.

BACKGROUND: Interferon-beta (IFN-beta) is one of the most widely prescribed medications for relapsing-remitting multiple sclerosis (RRMS). IFN-related thrombotic microangiopathy (TMA) is a rare but severe complication, with a fulminant clinical onset and a possibly life-threatening outcome that may occur years after a well-tolerated treatment with IFN. Most patients evolve rapidly to advanced chronic kidney disease and eventually to renal failure. METHODS: We performed a retrospective analysis of TMA cases diagnosed and managed in our Nephrology Department from 2010 to 2015, and performed a literature review of IFN-beta-induced TMA. RESULTS: Three cases of TMA among patients treated with IFN-beta were identified who did not show any renal improvement following conventional therapy: IFN withdrawal and plasma exchange (PE, range 8-18) sessions. All of them responded favourably to eculizumab, with progressive clinical and renal improvement, allowing dialysis discontinuation, without recurrence of TMA during a long-term follow-up (range 1-5 years). CONCLUSIONS: TMA is a recognized severe complication in RRMS patients treated with IFN-beta. Withdrawal of IFN and treatment with PE, steroids or rituximab did not improve the poor renal prognosis in our three patients and in all the previously described cases in the literature. In our experience, eculizumab had a strikingly favourable effect on renal recovery, suggesting a role of IFN-beta as a trigger in complement-mediated TMA. Neurologists and nephrologists should be vigilant to this complication to prevent possibly irreversible renal damage.

Structured clinical follow-up for CKD stage 5 may safely postpone dialysis.

BACKGROUND AND OBJECTIVES: The optimal timing of dialysis initiation is still unclear. We aimed to ascertain whether a strict clinical follow-up can postpone need for dialysis in chronic kidney disease (CKD) stage 5 patients. DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS: We reviewed records of all consecutive adult patients attending our conservative CKD stage 5 outpatient clinic from 2001 to 2010. Chronicity was defined as two consecutive estimated glomerular filtration rate (eGFR) measurements below 15 ml/min/1.73 m(2). Characteristics of subjects, including comorbidities, were assessed at baseline; blood pressure and serum markers of uremia were assessed both at first and last visit. GFR was estimated by the 4-variable Modification of Diet in Renal Disease (MDRD) formula. RESULTS: In the 312 patients analyzed baseline eGFR was 9.7 ± 2.7 ml/min, which declined by 1.93 ± 4.56 ml/min after 15.6 ± 18.2 months. Age was inversely related to eGFR decline (r -0.27, p = 0.000). During conservative follow-up 55 subjects (18%) died. In comparison with those eventually entering dialysis, deceased subjects were older and had a longer follow-up with no CKD progression. Multivariate analysis identified age, proteinuria and lower baseline K values as the only independent determinants of death. One hundred ninety-four subjects (66%) started dialysis with an average eGFR of 6.1 ± 1.9 ml/min. During 35.8 ± 24.7 months of dialysis follow-up, 84 patients died. Multivariate analysis identified age as the main determinant of death (hazard ratio [HR] for every year 1.07, 95% confidence interval [CI] 1.04-1.11, p 0.000). Patients starting dialysis with eGFR below the median, e.g. <5.7 ml/min, showed a better survival (HR for mortality 0.52, 95% CI 0.30-0.89, p 0.016) than the other group. CONCLUSIONS: A well-organized nephrological outpatient clinic for conservative follow-up of CKD stage five patients can delay dialysis entry as long as 1 year. Starting dialysis with eGFR lower than 6 ml/min does not confer any increased risk of death in selected early-referral patients.

Anti-human leukocyte antigen DQ antibodies in renal transplantation: Are we underestimating the most frequent donor specific alloantibodies?

The role of anti-human leukocyte antigens DQ region (HLA-DQ) in transplantation is historically less studied than HLA-DR and HLA class I regions, but several studies are demonstrating that anti HLA-DQ antibodies are among the most frequent anti HLA antibodies that develop after transplantation and can have great influence on the developing of humoral rejection and graft loss. In this article we review the gene structure and nomenclature of the HLA-DQ region, the role of anti HLA-DQ antibodies after and before transplantation and briefly the associations of particular HLA-DQ alleles and other diseases.