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Chitnis, Tanuja

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Chitnis

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Tanuja

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Chitnis, Tanuja
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Now showing 1 - 10 of 21
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    Modeling Disease Severity in Multiple Sclerosis Using Electronic Health Records
    (Public Library of Science, 2013) Xia, Zongqi; Secor, Elizabeth; Chibnik, Lori; Bove, Riley; Cheng, Suchun; Chitnis, Tanuja; Cagan, Andrew; Gainer, Vivian S.; Chen, Pei J.; Liao, Katherine; Shaw, Stanley; Ananthakrishnan, Ashwin; Szolovits, Peter; Weiner, Howard; Karlson, Elizabeth; Murphy, Shawn; Savova, Guergana; Cai, Tianxi; Churchill, Susanne E.; Plenge, Robert M.; Kohane, Isaac; De Jager, Philip
    Objective: To optimally leverage the scalability and unique features of the electronic health records (EHR) for research that would ultimately improve patient care, we need to accurately identify patients and extract clinically meaningful measures. Using multiple sclerosis (MS) as a proof of principle, we showcased how to leverage routinely collected EHR data to identify patients with a complex neurological disorder and derive an important surrogate measure of disease severity heretofore only available in research settings. Methods: In a cross-sectional observational study, 5,495 MS patients were identified from the EHR systems of two major referral hospitals using an algorithm that includes codified and narrative information extracted using natural language processing. In the subset of patients who receive neurological care at a MS Center where disease measures have been collected, we used routinely collected EHR data to extract two aggregate indicators of MS severity of clinical relevance multiple sclerosis severity score (MSSS) and brain parenchymal fraction (BPF, a measure of whole brain volume). Results: The EHR algorithm that identifies MS patients has an area under the curve of 0.958, 83% sensitivity, 92% positive predictive value, and 89% negative predictive value when a 95% specificity threshold is used. The correlation between EHR-derived and true MSSS has a mean R2 = 0.38±0.05, and that between EHR-derived and true BPF has a mean R2 = 0.22±0.08. To illustrate its clinical relevance, derived MSSS captures the expected difference in disease severity between relapsing-remitting and progressive MS patients after adjusting for sex, age of symptom onset and disease duration (p = 1.56×10−12). Conclusion: Incorporation of sophisticated codified and narrative EHR data accurately identifies MS patients and provides estimation of a well-accepted indicator of MS severity that is widely used in research settings but not part of the routine medical records. Similar approaches could be applied to other complex neurological disorders.
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    No sex-specific difference in disease trajectory in multiple sclerosis patients before and after age 50
    (BioMed Central, 2013) Bove, Riley; Musallam, Alexander; Healy, Brian; Houtchens, Maria; Glanz, Bonnie I; Khoury, Samia; Guttmann, Charles; De Jager, Philip; Chitnis, Tanuja
    Background: The disease course in multiple sclerosis (MS) is influenced by many factors, including age, sex, and sex hormones. Little is known about sex-specific changes in disease course around age 50, which may represent a key biological transition period for reproductive aging. Methods: Male and female subjects with no prior chemotherapy exposure were selected from a prospective MS cohort to form groups representing the years before (38–46 years, N=351) and after (54–62 years, N=200)age 50. Primary analysis assessed for interaction between effects of sex and age on clinical (Expanded Disability Status Scale, EDSS; relapse rate) and radiologic (T2 lesion volume, T2LV; brain parenchymal fraction, BPF) outcomes. Secondarily, we explored patient-reported outcomes (PROs). Results: As expected, there were age- and sex- related changes with male and older cohorts showing worse disease severity (EDSS), brain atrophy (BPF), and more progressive course. There was no interaction between age and sex on cross-sectional adjusted clinical (EDSS, relapse rate) or radiologic (BPF, T2LV) measures, or on 2-year trajectories of decline. There was a significant interaction between age and sex for a physical functioning PRO (SF-36): the older female cohort reported lower physical functioning than men (p=0.002). There were no differences in depression (Center for Epidemiological Study – Depression, CES-D) or fatigue (Modified Fatigue Impact Scale, MFIS) scores. Conclusions: There was no interaction between age and sex suggestive of an effect of reproductive aging on clinical or radiologic progression. Prospective analyses across the menopausal transition are needed.
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    Handling changes in MRI acquisition parameters in modeling whole brain lesion volume and atrophy data in multiple sclerosis subjects: Comparison of linear mixed-effect models
    (Elsevier, 2015) Chua, Alicia S.; Egorova, Svetlana; Anderson, Mark C.; Polgar-Turcsanyi, Mariann; Chitnis, Tanuja; Weiner, Howard; Guttmann, Charles R.G.; Bakshi, Rohit; Healy, Brian
    Magnetic resonance imaging (MRI) of the brain provides important outcome measures in the longitudinal evaluation of disease activity and progression in MS subjects. Two common measures derived from brain MRI scans are the brain parenchymal fraction (BPF) and T2 hyperintense lesion volume (T2LV), and these measures are routinely assessed longitudinally in clinical trials and observational studies. When measuring each outcome longitudinally, observed changes may be potentially confounded by variability in MRI acquisition parameters between scans. In order to accurately model longitudinal change, the acquisition parameters should thus be considered in statistical models. In this paper, several models for including protocol as well as individual MRI acquisition parameters in linear mixed models were compared using a large dataset of 3453 longitudinal MRI scans from 1341 subjects enrolled in the CLIMB study, and model fit indices were compared across the models. The model that best explained the variance in BPF data was a random intercept and random slope with protocol specific residual variance along with the following fixed-effects: baseline age, baseline disease duration, protocol and study time. The model that best explained the variance in T2LV was a random intercept and random slope along with the following fixed-effects: baseline age, baseline disease duration, protocol and study time. In light of these findings, future studies pertaining to BPF and T2LV outcomes should carefully account for the protocol factors within longitudinal models to ensure that the disease trajectory of MS subjects can be assessed more accurately.
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    An expanded composite scale of MRI-defined disease severity in multiple sclerosis: MRDSS2
    (Lippincott Williams & Wilkins, 2014) Bakshi, Rohit; Neema, M; Tauhid, Shahamat; Healy, Brian C.; Glanz, Bonnie; Kim, Gloria; Miller, Jennifer; Berkowitz, Julia L.; Bove, Riley; Houtchens, Maria; Severson, Christopher; Stankiewicz, James; Stazzone, Lynn; Chitnis, Tanuja; Guttmann, Charles R.G.; Weiner, Howard; Ceccarelli, Antonia
    The objective of this study was to test a new version of the Magnetic Resonance Disease Severity Scale (MRDSS2), incorporating cerebral gray matter (GM) and spinal cord involvement from 3 T MRI, in modeling the relationship between MRI and physical disability or cognitive status in multiple sclerosis (MS). Fifty-five MS patients and 30 normal controls underwent high-resolution 3 T MRI. The patients had an Expanded Disability Status Scale score of 1.6±1.7 (mean±SD). The cerebral normalized GM fraction (GMF), the T2 lesion volume (T2LV), and the ratio of T1 hypointense LV to T2LV (T1/T2) were derived from brain images. Upper cervical spinal cord area (UCCA) was obtained from spinal cord images. A within-subject d-score (difference of MS from normal control) for each MRI component was calculated, equally weighted, and summed to form MRDSS2. With regard to the relationship between physical disability and MRDSS2 or its individual components, MRI–Expanded Disability Status Scale correlations were significant for MRDSS2 (r=0.33, P=0.013) and UCCA (r=−0.33, P=0.015), but not for GMF (P=0.198), T2LV (P=0.707), and T1/T2 (P=0.240). The inclusion of UCCA appeared to drive this MRI–disability relationship in MRDSS2. With regard to cognition, MRDSS2 showed a larger effect size (P=0.035) than its individual components [GMF (P=0.081), T2LV (P=0. 179), T1/T2 (P=0.043), and UCCA (P=0.818)] in comparing cognitively impaired with cognitively preserved patients (defined by the Minimal Assessment of Cognitive Function in MS). Both cerebral lesions (T1/T2) and atrophy (GMF) appeared to drive this relationship. We describe a new version of the MRDSS, which has been expanded to include cerebral GM and spinal cord involvement. MRDSS2 has concurrent validity with clinical status.
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    Female hormonal exposures and neuromyelitis optica symptom onset in a multicenter study
    (Lippincott Williams & Wilkins, 2017) Bove, Riley; Elsone, Liene; Alvarez, Enrique; Borisow, Nadja; Cortez, Melissa M.; Mateen, Farrah; Mealy, Maureen A.; Mutch, Kerry; Tobyne, Sean; Ruprecht, Klemens; Buckle, Guy; Levy, Michael; Wingerchuk, Dean M.; Paul, Friedemann; Cross, Anne H.; Weinshenker, Brian; Jacob, Anu; Klawiter, Eric; Chitnis, Tanuja
    Objective: To study the association between hormonal exposures and disease onset in a cohort of women with neuromyelitis optica spectrum disorder (NMOSD). Methods: Reproductive history and hormone use were assessed using a standardized reproductive survey administered to women with NMOSD (82% aquaporin-4 antibody positive) at 8 clinical centers. Using multivariable regression, we examined the association between reproductive exposures and age at first symptom onset (FS). Results: Among 217 respondents, the mean age at menarche was 12.8 years (SD 1.7). The mean number of pregnancies was 2.1 (SD 1.6), including 0.3 (SD 0.7) occurring after onset of NMOSD symptoms. In the 117 participants who were postmenopausal at the time of the questionnaire, 70% reported natural menopause (mean age: 48.9 years [SD 3.9]); fewer than 30% reported systemic hormone therapy (HT) use. Mean FS age was 40.1 years (SD 14.2). Ever-use of systemic hormonal contraceptives (HC) was marginally associated with earlier FS (39 vs 43 years, p = 0.05). Because HC use may decrease parity, when we included both variables in the model, the association between HC use and FS age became more significant (estimate = 2.7, p = 0.007). Among postmenopausal participants, 24% reported NMOSD onset within 2 years of (before or after) menopause. Among these participants, there was no association between age at menopause or HT use and age at NMOSD onset. Conclusions: Overall, age at NMOSD onset did not show a strong relationship with endogenous hormonal exposures. An earlier onset age did appear to be marginally associated with systemic HC exposure, an association that requires confirmation in future studies.
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    Alterations of the human gut microbiome in multiple sclerosis
    (Nature Publishing Group, 2016) Jangi, Sushrut; Gandhi, Roopali; Cox, Laura; Li, Ning; von Glehn, Felipe; Yan, Raymond; Patel, Bonny; Mazzola, Maria; Liu, Shirong; Glanz, Bonnie; Cook, Sandra; Tankou, Stephanie; Stuart, Fiona; Melo, Kirsy; Nejad, Parham; Smith, Kathleen; Topçuolu, Begüm D.; Holden, James; Kivisakk, Pia; Chitnis, Tanuja; De Jager, Philip; Quintana, Francisco; Gerber, Georg; Bry, Lynn; Weiner, Howard
    The gut microbiome plays an important role in immune function and has been implicated in several autoimmune disorders. Here we use 16S rRNA sequencing to investigate the gut microbiome in subjects with multiple sclerosis (MS, n=60) and healthy controls (n=43). Microbiome alterations in MS include increases in Methanobrevibacter and Akkermansia and decreases in Butyricimonas, and correlate with variations in the expression of genes involved in dendritic cell maturation, interferon signalling and NF-kB signalling pathways in circulating T cells and monocytes. Patients on disease-modifying treatment show increased abundances of Prevotella and Sutterella, and decreased Sarcina, compared with untreated patients. MS patients of a second cohort show elevated breath methane compared with controls, consistent with our observation of increased gut Methanobrevibacter in MS in the first cohort. Further study is required to assess whether the observed alterations in the gut microbiome play a role in, or are a consequence of, MS pathogenesis.
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    Immunology of neuromyelitis optica during pregnancy
    (Lippincott Williams & Wilkins, 2016) Davoudi, Vahid; Keyhanian, Kiandokht; Bove, Riley M.; Chitnis, Tanuja
    Anti–aquaporin-4 (AQP4) autoantibody plays a key role in the pathogenesis of neuromyelitis optica (NMO). Studies have shown increased relapse rates in patients with NMO during pregnancy and postpartum. High estrogen levels during pregnancy can increase activation-induced cytidine deaminase expression, which is responsible for immunoglobulin production. Additionally, sex hormones may influence antibody glycosylation, with effects on antibody function. Estrogen decreases apoptosis of self-reactive B cells, through upregulation of antiapoptotic molecules. Furthermore, high estrogen levels during pregnancy can boost B-cell activating factor and type 1 interferon (IFN) production, facilitating development of self-reactive peripheral B cells in association with increased disease activity. Elevated levels of estrogen during pregnancy decrease IFN-γ generation, which causes a shift toward T helper (Th) 2 immunity, thereby propagating NMO pathogenesis. Women with NMO have an elevated rate of pregnancy complications including miscarriage and preeclampsia, which are associated with increased Th17 cells and reduction of T-regulatory cells. These in turn can enhance inflammation in NMO. Increased regulatory natural killer cells (CD56−) during pregnancy can enhance Th2-mediated immunity, thereby increasing inflammation. In the placenta, trophoblasts express AQP4 antigen and are exposed to maternal blood containing anti-AQP4 antibodies. Animal models have shown that anti-AQP4 antibodies can bind to AQP4 antigen in placenta leading to complement deposition and placental necrosis. Reduction of regulatory complements has been associated with placental insufficiency, and it is unclear whether these are altered in NMO. Further studies are required to elucidate the specific mechanisms of disease worsening, as well as the increased rate of complications during pregnancy in women with NMO.
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    Identification of a novel mechanism of action of fingolimod (FTY720) on human effector T cell function through TCF-1 upregulation
    (BioMed Central, 2015) Mazzola, Maria; Raheja, Radhika; Murugaiyan, Gopal; Rajabi, Hasan; Kumar, Deepak; Pertel, Thomas; Regev, Keren; Griffin, Russell; Aly, Lilian; Kivisakk, Pia; Nejad, Parham; Patel, Bonny; Gwanyalla, Nguendab; Hei, Hillary; Glanz, Bonnie; Chitnis, Tanuja; Weiner, Howard; Gandhi, Roopali
    Background: Fingolimod (FTY720), the first oral treatment for multiple sclerosis (MS), blocks immune cell trafficking and prevents disease relapses by downregulation of sphingosine-1-phosphate receptor. We determined the effect of FTY720 on human T cell activation and effector function. Methods: T cells from MS patients and healthy controls were isolated to measure gene expression profiles in the presence or absence of FTY720 using nanostring and quantitative real-time polymerase chain reaction (qPCR). Cytokine protein expression was measured using luminex assay and flow cytometry analysis. Lentivirus vector carrying short hairpin RNA (shRNA) was used to knock down the expression of specific genes in CD4+ T cells. Chromatin immunoprecipitation was performed to assess T cell factor 1 (TCF-1) binding to promoter regions. Luciferase assays were performed to test the direct regulation of interferon gamma (IFN-γ) and granzyme B (GZMB) by TCF-1. Western blot analysis was used to assess the phosphorylation status of Akt and GSK3β. Results: We showed that FTY720 treatment not only affects T cell trafficking but also T cell activation. Patients treated with FTY720 showed a significant reduction in circulating CD4 T cells. Activation of T cells in presence of FTY720 showed a less inflammatory phenotype with reduced production of IFN-γ and GZMB. This decreased effector phenotype of FTY720-treated T cells was dependent on the upregulation of TCF-1. FTY720-induced TCF-1 downregulated the pathogenic cytokines IFN-γ and GZMB by binding to their promoter/enhancer regions and mediating epigenetic modifications. Furthermore, we observed that TCF-1 expression was lower in T cells from multiple sclerosis patients than in those from healthy individuals, and FTY720 treatment increased TCF-1 expression in multiple sclerosis patients. Conclusions: These results reveal a previously unknown mechanism of the effect of FTY720 on human CD4+ T cell modulation in multiple sclerosis and demonstrate the role of TCF-1 in human T cell activation and effector function. Electronic supplementary material The online version of this article (doi:10.1186/s12974-015-0460-z) contains supplementary material, which is available to authorized users.
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    Complex relation of HLA-DRB1*1501, age at menarche, and age at multiple sclerosis onset
    (Wolters Kluwer, 2016) Bove, Riley; Chua, Alicia S.; Xia, Zongqi; Chibnik, Lori; De Jager, Philip; Chitnis, Tanuja
    Objective: To examine the relationship between 2 markers of early multiple sclerosis (MS) onset, 1 genetic (HLA-DRB1*1501) and 1 experiential (early menarche), in 2 cohorts. Methods: We included 540 white women with MS or clinically isolated syndrome (N = 156 with genetic data available) and 1,390 white women without MS but with a first-degree relative with MS (Genes and Environment in Multiple Sclerosis [GEMS]). Age at menarche, HLA-DRB1*1501 status, and age at MS onset were analyzed. Results: In both cohorts, participants with at least 1 HLA-DRB1*1501 allele had a later age at menarche than did participants with no risk alleles (MS: mean difference = 0.49, 95% confidence interval [CI] = [0.03–0.95], p = 0.036; GEMS: mean difference = 0.159, 95% CI = [0.012–0.305], p = 0.034). This association remained after we adjusted for body mass index at age 18 (available in GEMS) and for other MS risk alleles, as well as a single nucleotide polymorphism near the HLA-A region previously associated with age of menarche (available in MS cohort). Confirming previously reported associations, in our MS cohort, every year decrease in age at menarche was associated with a 0.65-year earlier MS onset (95% CI = [0.07–1.22], p = 0.027, N = 540). Earlier MS onset was also found in individuals with at least 1 HLA-DRB1*1501 risk allele (mean difference = −3.40 years, 95% CI = [−6.42 to −0.37], p = 0.028, N = 156). Conclusions: In 2 cohorts, a genetic marker for earlier MS onset (HLA-DRB1*1501) was inversely related to earlier menarche, an experiential marker for earlier symptom onset. This finding warrants broader investigations into the association between the HLA region and hormonal regulation in determining the onset of autoimmune disease.
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    Quantitative MRI study of Pineal Gland in MS.
    (2016) Egorova, Svetlana; Denes, Palma; Polgar-Turcsanyi, Mariann; Anderson, Mark; Cavallari, Michele; Guttmann, Charles; Glanz, Bonnie; Chitnis, Tanuja; Bove, Riley; Buckle, Guy; De Jager, Philip; Severson, Cristopher; Stankiewicz, James; Houtchens, Maria; Quintana, Francisco; Gandhi, Roopali; Webb, Pia; Meier, Dominik; Healy, Brian; Weiner, Howard