Cerebral vasculopathy in children with sickle cell disease A study of genetic modulators of the disease

Sickle cell disease (SCD) is a genetic disorder with recessive transmission, caused by the mutation HBB:c.20A>T. It originates hemoglobin S that forms polymers inside the erythrocyte, upon deoxygenation, deforming it and ultimately leading to premature hemolysis. The disease presents with high heterogeneity of clinical manifestations, the most devastating of which, ischemic stroke, occurs in 11% of patients until 20 years of age. In this study, we tried to identify genetic modifiers of risk and episodes of stroke by studying 66 children with SCD, grouped according to the degree of cerebral vasculopathy (Stroke, Risk and Control). Association studies were performed between the three phenotypic groups and hematological and biochemical parameters of patients, as well as with 23 polymorphic regions in genes related to vascular cell adhesion (VCAM-1, THBS-1 and CD36), vascular tonus (NOS3 and ET-1) and inflammation (TNF-α and HMOX-1). Relevant data was collected from patient’s medical records. Known genetic modulators of SCD (beta-globin cluster haplotype and HBA and BCL11A genotypes) and putative genetic modifiers of cerebral vasculopathy were characterized. Differences in their distribution among groups were assessed. VCAM-1 rs1409419 allele C and NOS3 rs207044 allele C were associated to stroke events, while VCAM-1 rs1409419 allele T was found to be protective. Alleles 4a and 4b of NOS3 27 bp VNTR appeared to be respectively associated to stroke risk and protection. HMOX-1 longer STRs seemed to predispose to stroke. Higher hemoglobin F levels were found in Control group, as a result of Senegal haplotype or of BCL11A rs11886868 allele T, and higher lactate dehydrogenase levels, marker of hemolysis, were found in Risk group. Molecular mechanisms underlying the modifier functions of the relevant genetic variants are discussed.

Microfluidics: a new look at cell migration analysis

This thesis explores the development and employment of microfluidic devices as a tool for studying the effect of the surrounding environment on embryonic stem cells during the migration phenomena. Different single-cell microchips were designed and manufactured to study mouse embryonic fibroblasts (MEFs) migration towards an environmental variation (increase of serum concentration in the culture medium) that was expected to function as a motility stimuli. Considering the experimental, cells were injected into the microchips chambers and individually isolated by dedicated cell traps with view to a single-cell analysis. Once fribroblasts were attached to the surface, culture medium with an increased serum level was subsequently injected in an adjacent chamber to promote the formation of a serum concentration gradient. The gradient established between the chambers could be sensed by the fibroblasts and thus triggered the cells mobilization towards and in the direction of the richer serum medium. Additionally, the experiment allowed the observation of MEFs’ structural reorganization when migrating through micro-tunnels containing widths below the cell size, suggesting a cytoskeleton rearrangement on account of the nutritional stimulus introduced. Furthermore, results indicate that fibronectin promotes MEFs adhesion to the substrate and that MEFs migration is characterized as haptotactic.

Chemotherapy versus best supportive care in stage IV non-small cell lung cancer, non metastatic to the brain

Stage IV non-small cell lung cancer is a fatal disease, with a median survival of 14 months. Systemic chemotherapy is the most common approach. However the impact in overall survival and quality of life still a controversy. OBJECTIVES: To determine differences in overall survival and quality of life among patients with stage IV non-small cell lung cancer non-metastatic to the brain treated with best supportive care versus systemic chemotherapy. PATIENTS: From February 1990 through December 1995, 78 eligible patients were admitted with the diagnosis of stage IV non-small cell lung cancer . Patients were divided in 2 groups: Group A (n=31 -- treated with best supportive care ), and Group B (n=47 -- treated with systemic chemotherapy). RESULTS: The median survival time was 23 weeks (range 5 -- 153 weeks) in Group A and 55 weeks (range 7.4 -- 213 weeks) in Group B (p=0.0018). In both groups, the incidence of admission for IV antibiotics and need of blood transfusions were similar. Patients receiving systemic chemotherapy were also stratified into those receiving mytomycin, vinblastin, and cisplatinum, n=25 and those receiving other combination regimens (platinum derivatives associated with other drugs, n=22). Patients receiving mytomycin, vinblastin, and cisplatinum, n=25 had a higher incidence of febrile neutropenia and had their cycles delayed for longer periods of time than the other group. These patients also had a shorter median survival time (51 versus 66 weeks, p=0.005). CONCLUSION: In patients with stage IV non-small cell lung cancer, non-metastatic to the brain, chemotherapy significantly increases survival compared with best supportive care.

Thumb metastasis from small cell lung cancer treated with radiation

A rare case of thumb metastasis from small cell lung cancer is presented. The patient underwent local radiotherapy with complete palliation of symptoms. She died 4 months later with disseminated disease. Considerations about incidence, treatment, and physiopathology of this kind of dissemination are made. Conservative treatment of finger metastasis with radiation may be considered due to the poor outcome of these patients.

Cell functional enviromics: applications to Pichia pastoris

The present PhD thesis develops the cell functional enviromics (CFE) method to investigate the relationship between environment and cellular physiology. CFE may be defined as the envirome-wide cellular function reconstruction through the collection and systems-level analysis of dynamic envirome data. Throughout the thesis, CFE is illustrated by two main applications to cultures of a constitutive P. pastoris X33 strain expressing a scFv antibody fragment. The first application addresses the challenge of culture media development. A dataset was built from 26 shake flask experiments, with variations in trace elements concentrations and basal medium dilution based on the standard BSM+PTM1. Protein yield showed high sensitivity to culture medium variations, while biomass was essentially determined by BSM dilution. High scFv yield was associated with high overall metabolic fluxes through central carbon pathways concomitantly with a relative shift of carbon flux from biosynthetic towards energy-generating pathways. CFE identified three cellular functions (growth, energy generation and by-product formation) that together described 98.8% of the variance in observed fluxes. Analyses of how medium factors relate to identified cellular functions showed iron and manganese at concentrations close to PTM1 inhibit overall metabolic activity. The second application addresses bioreactor operation. Pilot 50 L fed-batch cultivations, followed by 1H-NMR exometabolite profiling, allowed the acquisition of data for 21 environmental factors over time. CFE identified five major metabolic pathway groups that are frequently activated by the environment. The resulting functional enviromics map may serve as template for future optimization of media composition and feeding strategies for Pichia pastoris. The present PhD thesis is a step forward towards establishing the foundations of CFE that is still at its infancy. The methods developed herein are a contribution for changing the culture media and process development paradigm towards a holistic and systematic discipline in the future.

Effect of clarithromycin on the cell profile of bronchoalveolar lavage fluid in mice with neutrophil-predominant lung disease

OBJECTIVE: Macrolide antibiotics have anti-inflammatory properties in lung diseases. The aim of this study was to investigate the effect of clarithromycin in pulmonary cellular inflammatory response in mice. METHOD: Eight adult Swiss mice were studied. All animals received an intranasal challenge (80 µL) with dead Pseudomonas aeruginosa (1.0 x 10(12) CFU/mL). Bronchoalveolar lavage was performed 2 days later, with total cell count and differential cell analysis. The study group (n = 4) received clarithromycin treatment (50 mg/kg/day, intraperitoneal) for 5 days. Treatment was initiated 2 days before intranasal challenge. RESULTS: There was no significant difference in total cell count between the groups (mean: 2.0 x 10(6) and 1.3 x 10(6), respectively). In both groups, there was a predominance of neutrophils. However, the study group had a higher percentage of lymphocytes in the bronchoalveolar lavage than the control group (median of 19% vs 2.5%, P = .029). CONCLUSION: Clarithromycin alters the cytological pattern of bronchoalveolar lavage of Swiss mice with neutrophil pulmonary inflammation, significantly increasing the percentage of lymphocytes.

Nonsmall cell lung cancer: evaluation of 737 consecutive patients in a single institution

OBJECTIVE: To analyze surgical and pathological parameters and outcome and prognostic factors of patients with nonsmall cell lung cancer (NSCLC) who were admitted to a single institution, as well as to correlate these findings to the current staging system. METHOD: Seven hundred and thirty seven patients were diagnosed with NSCLC and admitted to Hospital do Cancer A. C. Camargo from 1990 to 2000. All patients were included in a continuous prospective database, and their data was analyzed. Following staging, a multidisciplinary team decision on adequate management was established. Variables included in this analysis were age, gender, histology, Karnofsky index, weight loss, clinical stage, surgical stage, chemotherapy, radiotherapy, and survival rates. RESULTS: 75.5% of patients were males. The distribution of histologic type was squamous cell carcinoma 51.8%, adenocarcinoma 43.1%, and undifferentiated large cell carcinoma 5.1%. Most patients (73%) presented significant weight loss and a Karnofsky index of 80%. Clinical staging was IA 3.8%, IB 9.2%, IIA 1.4%, IIB 8.1%, IIIA 20.9%, IIIB 22.4%, IV 30.9%. Complete tumor resection was performed in 24.6% of all patients. Surgical stage distribution was IA 25.3%, IB 1.4%, IIB 17.1%, IIIA 16.1%, IIIB 20.3%, IV 11.5%. Chemotherapy and radiotherapy were considered therapeutic options in 43% and 72%, respectively. The overall 5-year survival rate of nonsmall cell lung cancer patients in our study was 28%. Median survival was 18.9 months. CONCLUSIONS: Patients with NSCLC who were admitted to our institution presented with histopathologic and clinical characteristics that were similar to previously published series in cancer hospitals. The best prognosis was associated with complete tumor resection with lymph node dissection, which is only achievable in earlier clinical stages.

Coupling organic substrate removal to methane production in a fully biological microbial electrolysis cell

Microbial electrolysis cells (MECs) are an innovative and emerging technique based on the use of solid-state electrodes to stimulate microbial metabolism for wastewater treatment and simultaneous production of value-added compounds (such as methane). This research studied the performance of a two-chamber MEC in terms of organic matter oxidation (at the anode) and methane production (at the cathode). MEC‟s anode had been previously inoculated with an activated sludge, whereas the cathode chamber inoculum was an anaerobic sludge (containing methanogenic microorganisms). During the experimentation, the bioanode was continuously fed with synthetic solutions in anaerobic basal medium, at an organic load rate (OLR) of around 1 g L-1 d-1, referred to the chemical oxygen demand (COD). At the beginning (Run I), the feeding solution contained acetate and subsequently (Run II) it was replaced with a more complex solution containing soluble organic compounds other than acetate. For both conditions, the anode potential was controlled at -0.1 V vs. standard hydrogen electrode, by means of a potentiostat. During Run I, over 80% of the influent acetate was anaerobically oxidized at the anode, and the resulting electric current was recovered as methane at the cathode (with a cathode capture efficiency, CCE, accounting around 115 %). The average energy efficiency of the system (i.e., the energy captured into methane relative to the electrical energy input) under these conditions was over 170%. However, reactor‟s performance decreased over time during this run. Throughout Run II, a substrate oxidation over 60% (on COD basis) was observed. The electric current produced (57% of coulombic efficiency) was also recovered as methane, with a CCE of 90%. For this run the MEC‟s average energy efficiency accounted for almost 170 %. During all the experimentation, a very low biomass growth was observed at the anode whereas ammonium was transferred through the cationic membrane and concentrated at the cathode. Tracer experiments and scanning electron microscopy analyses were also carried out to gain a deeper insight into the reactor performance and also to investigate the possible reasons for partial loss of performance. In conclusion, this research suggests the great potential of MEC to successfully treat low-strength wastewaters, with high energy efficiency and very low sludge production.

Fucoidan-based particles for diabetes mellitus treatment

Marine organisms are rich in a variety of materials with potential use in Tissue Engineering and Regenerative Medicine. One important example is fucoidan, a sulfated polysaccharide extracted from the cell wall of brown seaweeds.  Fucoidan is composed by L-fucose, sulfate groups and glucuronic acid. It has important bioactive properties such as anti-oxidative, anticoagulant, anticancer and reducing the blood glucose (1). In this work, the biomedical potential of fucoidan-based materials as drug delivery system was assessed by processing modified fucoidan (MFu) into particles by photocrosslinking using superamphiphobic surfaces and visible light. Fucoidan was modified by methacrylation reaction using different concentrations of methacrylate anhydride, namely 8% v/v (MFu1) and 12% v/v (MFu2). Further, MFu particles with and without insulin (5% w/v) were produced by pipetting a solution of 5% MFu with triethanolamine and eosin-y onto a superamphiphobic surface and then photocrosslinking using visible light (2). The developed particles were characterized to assess their chemistry, morphology, swelling behavior, drug release, insulin content and encapsulation efficiency. Moreover, the viability assays of fibroblast L929 cells in contact with MFu particles showed good adhesion and proliferation up to 14 days. Furthermore, the therapeutic potential of these particles using human beta cells is currently under investigation. Results obtained so far suggest that modified fucoidan particles could be a good candidate for diabetes mellitus therapeutic approaches.  

Xenogeneic M2-polarization of Macrophages by undifferentiated and differentiated adipose tissue-derived stem cells

Mesenchymal stem cells (MSCs) are considered to be â â immunologically privileged.â â In a previous work when human adipose tissue-derived stem cells (hASCs) subcutaneously implanted in mice we did not identify an adverse host response1. Recently, it was shown that tissue regeneration could benefit from the polarization of M2 macrophages subpopulations 2. In this study we hypothesised that undifferentiated hASCs and derived osteoblasts and chondrocytes are able to switch murine bone marrow-derived macrophages (mBMMÃ s) into M2 phenotype, aiding tissue regeneration. Murine BMMÃ s were plated in direct contact with undifferentiated and osteo or chondro-differentiated hASCs for 4 h, 10 h, 24 h and 72 h. The cytokine profile was analysed by qRT-PCR and the surface markers were detected by flow cytometry. The direct interaction of both cell types was observed by time lapse microscopy. The results showed that mBMMÃ s polarized after contacting tissue culture polystyrene. This M2 phenotype was maintained along the experiment in direct contact with both undifferentiated and osteo or chondro-differentiated hASCs. This was confirmed by the expression of IL-1, IL-10, IL-4, TNF-a and IFN-g (genetic profile) and surface markers (CD206 + + , CD336 + + , MHC II + and CD86 + + ) detection. These data suggest the potential of hASCs in contemporary xenogenic tissue engineering and regenerative medicine strategies, as well as host immune system modulation in autoimmune diseases. 

Release of insulin from PLGA-alginate dressing stimulates regenerative healing of burn wounds in rats

Burn wound healing involves a complex set of overlapping processes in an environment conducive to ischemia, inflammation, and infection costing $7.5 billion/year in the US alone, in addition to the morbidity and mortality that occur when the burns are extensive. We previously showed that insulin, when topically applied to skin excision wounds, accelerates re-epithelialization, and stimulates angiogenesis. More recently, we developed an alginate sponge dressing (ASD) containing insulin encapsulated in PLGA microparticles that provides a sustained release of bioactive insulin for >20days in a moist and protective environment. We hypothesized that insulin-containing ASD accelerates burn healing and stimulates a more regenerative, less scarring, healing. Using a heat-induced burn injury in rats, we show that burns treated with dressings containing 0.04mg insulin/cm2, every three days for 9 days, have faster closure, faster rate of disintegration of dead tissue, and decreased oxidative stress.In addition, in insulin-treated wounds the pattern of neutrophil inflammatory response suggests faster clearing of the burn dead tissue. We also observe faster resolution of the pro-inflammatory macrophages. We also found that insulin stimulates collagen deposition and maturation with the fibers organized more like a basket weave (normal skin) than aligned and crosslinked (scar tissue). In summary , application of ASD-containing insulin-loaded PLGA particles on burns every three days stimulates faster and more regenerative healing. These results suggest insulin as a potential therapeutic agent in burn healing and, because of its long history of safe use in humans, insulin could become one of the treatments of choice when repair and regeneration are critical for proper tissue function.

In vitro chondrogenic commitment of human Wharton's jelly stem cells by co-culture with human articular chondrocytes.

Wharton's jelly stem cells (WJSCs) are a potential source of transplantable stem cells in cartilage-regenerative strategies, due to their highly proliferative and multilineage differentiation capacity. We hypothesized that a non-direct co-culture system with human articular chondrocytes (hACs) could enhance the potential chondrogenic phenotype of hWJSCs during the expansion phase compared to those expanded in monoculture conditions. Primary hWJSCs were cultured in the bottom of a multiwell plate separated by a porous transwell membrane insert seeded with hACs. No statistically significant differences in hWJSCs duplication number were observed under either of the culture conditions during the expansion phase. hWJSCs under co-culture conditions show upregulations of collagen type I and II, COMP, TGFβ1 and aggrecan, as well as of the main cartilage transcription factor, SOX9, when compared to those cultured in the absence of chondrocytes. Chondrogenic differentiation of hWJSCs, previously expanded in co-culture and monoculture conditions, was evaluated for each cellular passage using the micromass culture model. Cells expanded in co-culture showed higher accumulation of glycosaminoglycans (GAGs) compared to cells in monoculture, and immunohistochemistry for localization of collagen type I revealed a strong detection signal when hWJSCs were expanded under monoculture conditions. In contrast, type II collagen was detected when cells were expanded under co-culture conditions, where numerous round-shaped cell clusters were observed. Using a micromass differentiation model, hWJSCs, previously exposed to soluble factors secreted by hACs, were able to express higher levels of chondrogenic genes with deposition of cartilage extracellular matrix components, suggesting their use as an alternative cell source for treating degenerated cartilage.

Skin-derived cell-sheets as powerful tools to engineer skin analogues

Cell/cell-extracellular matrix (ECM) dynamic interactions appear to have a major role in regulating communication through soluble signaling, directing cell binding and activating substrates that participate in the highly organized wound healing process. Moreover, these interactions are also crucial for in vitro mimicking cutaneous physiology. Herein we explore cell sheet (CS) engineering to create cellular constructs formed by keratinocytes (hKC), fibroblasts (hDFB) and dermal microvascular endothelial cells (hDMEC), to target skin wound healing but also the in vitro recreation of relevant models. Taking advantage of temperature-responsive culture surfaces, which allow harvesting cultured cells as intact sheets along with the deposited native ECM, varied combinations of homotypic and heterotypic three-dimensional (3-D) CS-based constructs were developed. Constructs combining one CS of keratinocytes as an epidermis-like layer plus a vascularized dermis composed by hDFB and hDMECs were assembled as skin analogues for advancing in vitro testing. Simultaneously both hKC and hDMEC were shown to significantly contribute to the re-epithelialization of full-thickness mice skin wounds by promoting an early epithelial coverage, while hDMEC significantly lead to increased vessels density, incorporating the neovasculature. Thus, although determined by the cellular nature of the constructs, these outcomes demonstrated that CS engineering appear as an unique technology that open the possibility to create numerous combinations of 3D constructs to target defective wound healing as well as the construction of in vitro models to further mimic cutaneous functions crucial for drug screening and cosmetic testing assays.

Algorithms and tools for in silico design of cell factories

PhD thesis in Bioengineering