From bench to patient and back - an interdisciplinary mixed-method patient-integrated approach to developing a new potential therapy for inflammatory bowel disease

Inflammatory Bowel Disease (IBD) is life-changing because of recurrent intestinal inflammation. Current therapies are associated with mild to severe side effects, and none provide a cure. Recent research has provided pre-clinical and clinical data on cell-based therapy using the two best-characterized types of T regulatory cells, Foxp3⁺ Tregs and Foxp3⁻ Type 1 regulatory (Tr1) cells. However, major hurdles exist. The ability of Tregs to regulate innate immunity is not well understood, and while high numbers of antigen-specific Tregs are needed, these cells are scarce. Studies showed that engineered chimeric antigen receptor-expressing Tregs (CAR-Treg) could curb intestinal inflammation, but these CARs were not relevant to human disease. CAR-Treg therapy is logistically and conceptually complex and patients might perceive an unacceptable risk to be associated with this therapy. Finally, people living with IBD have an increased risk of Clostridioides difficile infection (CDI), the most prevalent cause of nosocomial infectious diarrhea in Canada, and patient experiences with CDI have not been researched. The purpose of this thesis was to elucidate how Tr1 cells and/or Tregs regulate innate immunity, which I addressed by investigating the suppressive effect of Tr1 and Tregs on the inflammasome. I then developed and tested a new CAR-Treg relevant to human IBD and conducted a survey to investigate patients’ willingness to try CAR-Treg. Finally, I analyzed a survey to describe the impact of CDI on patients in Canada. My results demonstrate that Tr1 cells may have unique therapeutic effects in reducing inflammasome activation via Interleukin 10. I provide evidence that CAR-Tregs suppress proinflammatory T cells. People with IBD indicated high willingness to try CAR-Treg therapy in both a clinical trial and as a new treatment. Willingness to try was not correlated with disease state or medication history. Finally, CDI patients highlighted the symptom-related impact and long-lasting effect on quality of life. Patient priorities to attenuate impact include reducing time to diagnosis and improving patient education. My research has implications on future development of Treg-based therapy for IBD and other immune-mediated diseases and demonstrates the promise of moving this therapy into clinical practice, as most patients indicated willingness to try.Medicine, Faculty ofExperimental Medicine, Division ofMedicine, Department ofGraduat

Indirect viscosimetric method is less accurate than ektacytometry for the measurement of red blood cell deformability.

International audienceThe aim of this study was to test the accuracy of viscosimetric method to estimate the red blood cell (RBC) deformability properties. Thirty-three subjects were enrolled in this study: 6 healthy subjects (AA), 11 patients with sickle cell-hemoglobin C disease (SC) and 16 patients with sickle cell anemia (SS). Two methods were used to assess RBC deformability: 1) indirect viscosimetric method and 2) ektacytometry. The indirect viscosimetric method was based on the Dintenfass equation where blood viscosity, plasma viscosity and hematocrit are measured and used to calculate an index of RBC rigidity (Tk index). The RBC deformability/rigidity of the three groups was compared using the two methods. Tk index was not different between SS and SC patients and the two groups had higher values than AA group. When ektacytometry was used, RBC deformability was lower in SS and SC groups compared to the AA group and SS and SC patients were different. Although the two measures of RBC deformability were correlated, the association was not very high. Bland and Altman analysis demonstrated a 3.25 bias suggesting a slight difference between the two methods. In addition, the limit of agreement represented 28% (>15%) of the mean values of RBC deformability, showing no interchangeability between the two methods. In conclusion, measuring RBC deformability by indirect viscosimetry is less accurate than by ektacytometry, which is considered the gold standard

Engineered Tolerance: Tailoring Development, Function, and Antigen-Specificity of Regulatory T Cells

Regulatory T cells (Tregs) are potent suppressors of immune responses and are currently being clinically tested for their potential to stop or control undesired immune responses in autoimmunity, hematopoietic stem cell transplantation, and solid organ transplantation. Current clinical approaches aim to boost Tregs in vivo either by using Treg-promoting small molecules/proteins and/or by adoptive transfer of expanded Tregs. However, the applicability of Treg-based immunotherapies continues to be hindered by technical limitations related to cell isolation and expansion of a pure, well-characterized, and targeted Treg product. Efforts to overcome these limitations and improve Treg-directed therapies are now under intense investigation in animal models and pre-clinical studies. Here, we review cell and protein engineering-based approaches that aim to target different aspects of Treg biology including modulation of IL-2 signaling or FOXP3 expression, and targeted antigen-specificity using transgenic T cell receptors or chimeric antigen receptors. With the world-wide interest in engineered T cell therapy, these exciting new approaches have the potential to be rapidly implemented and developed into therapies that can effectively fine-tune immune tolerance

Blood Thixotropy in Patients with Sickle Cell Anaemia: Role of Haematocrit and Red Blood Cell Rheological Properties - Figure 3

<p>A–C: Blood viscosity hysteresis loop (3A), differences between the two blood viscosity curves of the loop obtained on Fig. 3A (3B) and blood thixotropic index in patients with sickle cell anaemia (SS) and healthy individuals (AA) at 40% haematocrit. Significant difference: *p<0.05.</p

Properties of ThF_<i>x</i> from Infrared Spectra in Solid Argon and Neon with Supporting Electronic Structure and Thermochemical Calculations

Laser-ablated Th atoms react with F₂ in condensing noble gases to give ThF₄ as the major product. Weaker higher frequency infrared absorptions at 567.2, 564.8 (576.1, 573.8) cm^–1, 575.1 (582.7) cm^–1 and 531.0, (537.4) cm^–1 in solid argon (neon) are assigned to the ThF, ThF₂ and ThF₃ molecules based on annealing and photolysis behavior and agreement with CCSD­(T)/aug-cc-pVTZ vibrational frequency calculations. Bands at 528.4 cm^–1 and 460 cm^–1 with higher fluorine concentrations are assigned to the penta-coordinated species (ThF₃)­(F₂) and ThF₅^–. These bands shift to 544.2 and 464 cm^–1 in solid neon. The ThF₅ molecule has the (ThF₃)­(F₂) <i>C</i>_<i>s</i> structure and is essentially the unique [ThF₃⁺]­[F₂^–] ion pair based on charge and spin density calculations. Electron capture by (ThF₃)­(F₂) forms the trigonal bipyramidal ThF₅^– anion in a highly exothermic process. Extensive structure and frequency calculations were also done for thorium oxyfluorides and Th₂F_4,6,8 dimer species. The calculations provide the ionization potentials, electron affinities, fluoride affinities, Th–F bond dissociation energies, and the energies to bind F₂ and F₂^– to a cluster as well as dimerization energies

Red blood cell (RBC) deformability at different shear stresses in patients with sickle cell anaemia (SS) and healthy individuals (AA).

<p>Significant difference: ***p<0.001.</p><p>Red blood cell (RBC) deformability at different shear stresses in patients with sickle cell anaemia (SS) and healthy individuals (AA).</p

Definition of the rheological and hemorheological terms.

<p>Definition of the rheological and hemorheological terms.</p

Hemorheological risk factors of acute chest syndrome and painful vaso-occlusive crisis in children with sickle cell disease.: Blood rheology in sickle cell disease

International audienceBACKGROUND: Little is known about the effects of blood rheology on the occurrence of acute chest syndrome and painful vaso-occlusive crises in children with sickle cell anemia and hemoglobin SC disease. DESIGN AND METHODS: To address this issue, steady-state hemorheological profiles (blood viscosity, red blood cell deformability, aggregation properties) and hematologic parameters were assessed in 44 children with sickle cell anemia and 49 children with hemoglobin SC disease (8-16 years old) followed since birth. Clinical charts were retrospectively reviewed to determine prior acute chest syndrome or vaso-occlusive episodes, and rates of these complications were calculated. RESULTS: Multivariate analysis revealed that: 1) a higher steady-state blood viscosity was associated with a higher rate of vaso-occlusive crises in children with sickle cell anemia, but not in children with hemoglobin SC disease; 2) a higher steady-state red blood cell disaggregation threshold was associated with previous history of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia. CONCLUSIONS: Our results indicate for the first time that the red blood cell aggregation properties may play a role in the pathophysiology of acute chest syndrome in children with hemoglobin SC disease and boys with sickle cell anemia. In addition, whereas greater blood viscosity is associated with a higher rate of vaso-occlusive crises in children with sickle cell anemia, no association was found in children with hemoglobin SC disease, underscoring differences in the etiology of vaso-occlusive crises between sickle cell anemia and hemoglobin SC disease