Publications by authors named "Debra D Pittman"

Background:  Fidanacogene elaparvovec, an adeno-associated virus-based gene therapy vector expressing the high-activity factor IX (FIX) variant FIX-R338L, is in development for hemophilia B. One-stage clotting (OS) assays and chromogenic substrate (CS) assays are commonly used to measure FIX-R338L variant activity. Data from ongoing trials suggest FIX activity varies between different OS and CS assays.

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Individuals with sickle cell disease (SCD) experience vaso-occlusive crises (VOC). Historically, VOC episodes have been assessed through medical utilization, thereby excluding events managed at home. In order to validate a daily patient-reported outcome for patients with SCD to accurately report their VOC status and experience of a pain crisis, a SCD Diary was included in Evaluation of Longitudinal Pain Study in Sickle Cell Disease (ELIPSIS), a longitudinal, six-month, non-interventional study.

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Background: Patients with hemophilia have deficiencies in intrinsic coagulation factors and can develop inhibitors that limit the effectiveness of replacement coagulation factors. Marstacimab, a human monoclonal antibody, binds and inhibits the human tissue factor pathway inhibitor. Marstacimab is currently under development as a potential prophylactic treatment to prevent bleeding episodes in patients with hemophilia A and B.

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Article Synopsis
  • This study investigates pain related to vaso-occlusive crises (VOCs) in sickle cell disease (SCD) patients, highlighting the lack of objective pain biomarkers and variability in healthcare usage.
  • A longitudinal 6-month trial involved 37 SCD participants who used an electronic patient-reported outcome tool and actigraph devices to track pain, activity, and biomarkers during reported VOC days.
  • Results demonstrated significant changes in pain, functionality, and specific biomarkers during VOC days, suggesting that patient-reported data can effectively monitor at-home pain and contribute to future clinical trials in SCD.
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Erythroferrone (ERFE) is produced by erythroblasts in response to erythropoietin (EPO) and acts in the liver to prevent hepcidin stimulation by BMP6. Hepcidin suppression allows for the mobilization of iron to the bone marrow for the production of red blood cells. Aberrantly high circulating ERFE in conditions of stress erythropoiesis, such as in patients with β-thalassemia, promotes the tissue iron accumulation that substantially contributes to morbidity in these patients.

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Introduction: Tissue factor pathway inhibitor (TFPI) is an endogenous inhibitor of the extrinsic pathway that negatively regulates thrombin production during coagulation. Under haemophilic conditions, where the intrinsic coagulation pathway is impaired, inhibition of TFPI may improve clotting.

Aim: We investigated the ex vivo effects of a human TFPI neutralizing antibody, marstacimab (previously PF-06741086), in coagulation assays including rotational thromboelastometry (ROTEM), thrombin generation assay (TGA) and the dilute prothrombin time (dPT) assay, performed in haemophilic whole blood and plasmas.

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This paper presents a systemic investigation of ADA development and ADA impact of a human coagulation factor in nonclinical species during drug development and provides insights into potential implications in human if a similar ADA occurs. FXa-induced ADA response was characterized in monkey, mouse, rat, and dog in different studies, and ADA effects on pharmacokinetic and/or pharmacodynamics of FXa were further examined in ADA-negative and ADA-positive animals. After repeated administrations, FXa elicited a dose and exposure day-dependent ADA response which ranged from no response to a transient or persistent response.

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This phase Ib study randomized patients with stable sickle cell disease (SCD) aged 18-65 years to twice-daily PF-04447943 (a phosphodiesterase 9A inhibitor; 5 or 25 mg) or placebo, with/without hydroxyurea coadministration, for up to 29 days. Blood samples were collected at baseline and various posttreatment time points for assessments of PF-04447943 pharmacokinetics (PKs)/pharmacodynamics (PDs). Change from baseline in potential SCD-related biomarkers was evaluated.

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Tissue factor pathway inhibitor (TFPI) exhibits multiple isoforms, which are known to present in multiple locations such as plasma, endothelium, and platelets. TFPI is an endogenous negative modulator of the coagulation pathway, and therefore, neutralization of TFPI function can potentially increase coagulation activity. A human monoclonal antibody, PF-06741086, which interacts with all isoforms of TFPI is currently being tested in clinic for treating hemophilia patients with and without inhibitors.

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FXa is a recombinant human FXa variant which is currently being evaluated in the clinic for treating intracerebral hemorrhage. The aim of our studies is to investigate overall pharmacokinetics, pharmacodynamics, and distribution of FXa in preclinical species, and to understand its potential implication in human. Pharmacokinetics of FXa was examined using active site probes and the results showed that FXa displayed fast clearance, low volume of distribution, and a very short plasma resident time in mice, rats, and monkeys.

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Article Synopsis
  • Effective therapies for excessive bleeding are necessary, and a new variant of coagulation factor Xa (FXa(I16L)) shows promise in improving hemostasis.
  • FXa(I16L) is more stable than the wild-type version, with a longer half-life, and does not lead to overactivation of coagulation in hemophilic mouse models.
  • This variant enhances blood clot formation effectively and may serve as a rapid treatment option for various bleeding disorders, potentially outperforming existing treatments like FVIIa.
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Metformin (Met), an AMP-activated protein kinase (AMPK) inducer, is primarily transported by organic cation transporters expressed at the surface of renal proximal tubular epithelial cells. However, the implication of Met in renal function remains poorly understood. Interestingly, AICAR, another AMPK inducer, has been shown to inhibit the Unfolded Protein Response (UPR) generated by tunicamycin in cardiomyocytes in an AMPK-kinase dependent fashion suggesting metformin may also block the UPR.

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The RAGE (receptor for advanced glycation end products) is believed to play a role in sepsis by perpetuating inflammation. The interaction of RAGE with a variety of host-derived ligands that accumulate during stress and inflammation further induces the expression of RAGE. It was previously shown that a rat anti-RAGE monoclonal antibody protected mice from lethality in a cecal ligation and puncture model.

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A neutralizing antibody to the receptor for the advanced glycation end products (anti-RAGE Ab) was developed as a potential treatment of acute and chronic inflammatory conditions. Previous pharmacology studies demonstrated efficacy of the anti-RAGE antibody in the mouse model of sepsis. We examined pharmacokinetics and lung distribution of [125I]anti-RAGE Ab in RAGE-/- and wild-type (129S5) mice following single IV administration.

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IL-22 is made by a unique set of innate and adaptive immune cells, including the recently identified noncytolytic NK, lymphoid tissue-inducer, Th17, and Th22 cells. The direct effects of IL-22 are restricted to nonhematopoietic cells, its receptor expressed on the surface of only epithelial cells and some fibroblasts in various organs, including parenchymal tissue of the gut, lung, skin, and liver. Despite this cellular restriction on IL-22 activity, we demonstrate that IL-22 induces effects on systemic biochemical, cellular, and physiological parameters.

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The receptor for advanced glycation end products (RAGE) is a multiligand transmembrane receptor implicated in a number of diseases including autoimmune diseases. To further understand the pathogenic mechanism of RAGE in these diseases, we searched for additional ligands. We discovered that C3a bound to RAGE with an EC(50) of 1.

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Objectives: To investigate the expression and function of triggering receptor expressed on myeloid cells-1 (TREM-1) in the synovium of human RA patients as well as the level of soluble TREM-1 in the plasma of RA patients.

Methods: Twenty-four RA synovial samples were analysed by gene expression oligonucleotide microarrays. Expression levels of TREM-1 mRNA in murine CIA paws were determined by quantitative PCR (qPCR).

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Antibodies that neutralize RAGE (receptor for advanced glycation end products)-ligand interactions have potential therapeutic applications in both acute and chronic diseases. We generated XT-M4, a rat anti-RAGE monoclonal antibody that has in vivo efficacy in an acute sepsis model. This antibody was subsequently humanized.

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Objective: The present study was conducted to characterize the expression of the cysteine protease legumain in murine and human atherosclerotic tissues, and to explore the molecular mechanisms by which legumain may contribute to the pathophysiology of atherosclerosis.

Methods And Results: Using microarray analysis, legumain mRNA expression was found to increase with development of atherosclerosis in the aorta of aging Apolipoprotein E deficient mice while expression remained at low level and unchanged in arteries of age-matched C57BL/6 control mice. In situ hybridization and immunohistochemical analysis determined that legumain was predominantly expressed by macrophages in the atherosclerotic aorta, in lesions at the aortic sinus and in injured carotid arteries of Apolipoprotein E deficient mice as well as in inflamed areas in advanced human coronary atherosclerotic plaques.

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Introduction: The receptor for advanced glycation end products (RAGE), a multi-ligand member of the immunoglobulin superfamily, contributes to acute and chronic disease processes, including sepsis.

Methods: We studied the possible therapeutic role of RAGE inhibition in the cecal ligation and puncture (CLP) model of polymicrobial sepsis and a model of systemic listeriosis using mice genetically deficient in RAGE expression or mice injected with a rat anti-murine RAGE monoclonal antibody.

Results: The 7-day survival rates after CLP were 80% for RAGE-/- mice (n = 15) (P < 0.

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The functional and structural alterations of vascular endothelium contribute to the initiation, progression, and complications of atherosclerotic plaque formation, but limited information is known about the molecular composition and pathways underlying pathological changes during atherosclerosis. We have developed an affinity proteomic strategy for in situ isolation and differential mapping of vascular endothelial proteins in normal and atherosclerotic aorta tissues. The selective labeling was carried out by perfusion of the blood vessels with an active biotin reagent for covalent modification of accessible vascular endothelial proteins.

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Rheumatoid arthritis (RA) is a chronic inflammatory arthritis. Currently, diagnosis of RA may take several weeks, and factors used to predict a poor prognosis are not always reliable. Gene expression in RA may consist of a unique signature.

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Article Synopsis
  • The osteogenic potential of first-generation adenoviral vectors carrying human bone morphogenetic proteins (BMPs) is limited in normal (immunocompetent) animals.
  • The study involved two main experiments: one focused on comparing the effects of human and rat BMP6 adenoviral vectors, which showed similar osteogenic activities in both types of rats.
  • The findings suggest that the level of viral gene expression and the origin of BMP cDNA do not significantly affect the osteogenic potential of these vectors in immunocompetent hosts.
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The osteogenic potential of AAV5hBMP6 was compared with that of ADhBMP6 in immunodeficient and immunocompetent rats. AAV5hBMP6 (2.3 x 10(12) particles) and ADhBMP6 (5 x 10(7) PFU) elicited viral antibody production in immunocompetent rats.

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Introduction: Articular cartilage matrix synthesis and degradation are dynamic processes that must be balanced for proper maintenance of the tissue. In osteoarthritis (OA), this balance is skewed toward degradation and ultimate loss of matrix. The transcriptional and/or activity levels of hundreds of genes are dysregulated in chondrocytes from osteoarthritic cartilage, and a subset of these genes may represent pivotal factors that could be modulated if their specific role in the disease process could be identified.

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