Fluid flow is a complex and dynamic process in the brain, taking place at the macro- and microscopic level. Interstitial fluid in particular flows throughout the interstitial spaces within the tissue, interacting with cells and the extracellular matrix. We are coming to find that this interstitial fluid flow plays an important role in both homeostatic and pathologic conditions. It helps to transport chemokines and other molecules such as extracellular vesicles within the environment, clear waste from the brain, and provide biophysical cues to cells. When this flow is disrupted however, such as in glioblastoma or Alzheimer's disease, profound events can occur, for example the build-up of plaques or an increase in tumor cell invasion. While there has recently been an up-tick in interstitial fluid flow research, there is surprisingly little known about its exact nature within the interstitial space and its effects on brain pathology such as glioblastoma. In particular, ways to manipulate and measure brain IFF magnitude at the cellular level are lacking. In this dissertation, a set of tools is created and used to explore the role that interstitial fluid flow magnitude plays in the brain through the lens of glioma invasion. We developed and implemented a flow device that is used in conjunction with an established in vitro tissue culture insert assay to manipulate fluid flow rates through a 3D matrix of tumor cells. We showed that this flow device is biocompatible and accurately recreates flow rates that have been measured previously through the use of MRI. We quantified tumor cell invasion from several glioma cell lines using this device to show a nonlinear trend of invasion in response to increasing fluid flow magnitudes. In addition, we developed a computational model to explore one potential mechanism that fluid flow magnitude might be modulating: autologous chemotaxis. Through this model we showed that increased flow magnitudes such as those seen in gliomas cause an increase in the distribution of the chemokine gradient around a cell of interest, that the morphology of the cell is important to this gradient formation, that temporal effects should not be overlooked, and that within the tumor environment, a minimum distance is required for the invading cell to develop this gradient. Finally, we developed a novel in vivo surgical technique that allows for the manipulation and measurement of interstitial fluid flow within the brain through simultaneous multiphoton imaging. We showed that this technique can be used to modulate interstitial fluid flow, as a mechanism by which to label cells of interest, and as a means to implant and monitor glioma progression. Through these means we further characterize interstitial fluid flow in the brain, allowing for its manipulation and measurement, and examine the ability of increased interstitial fluid flow magnitudes to impact glioma invasion. / Doctor of Philosophy / Fluid flows throughout brain tissue and plays an important role in creating normal conditions for proper brain function. This fluid can also play a role in brain cancer, such as glioblastoma, by causing cancer cells to travel further into the brain which is not desirable. This dissertation seeks to understand fluid flow better by studying how its speed contributes to cancer cell movement which is accomplished through the development of several tools. One tool is a new surgical technique that allows for the measurement and manipulation of fluid flow speed within the mouse brain and visualization of cells of interest, one tool is a flow device that changes fluid flow speed through cells in a gel, and the last is a computational model that predicts how a cell might move under different flow and environmental conditions. The tools were created and utilized, showing several interesting results. Using the flow device, different cancer cell lines were seen to react differently to increased fluid flow speed with two main trends: 1) increased cancer cell movement with increased fluid flow speed and 2) a peak effect where the cell movement started to increase with increasing fluid flow speed and then decreased after a certain fluid flow speed was surpassed. The surgical technique was successful at introducing fluid flow and allowed for reproducible measurements of fluid flow speed. It also was used to introduce stains that show specific cells of interest. The computational model showed that there are specific time and spatial contributions that effect cancer cell movement and that with increased fluid flow speed, cells might be able to more easily utilize a specific mechanism to move. Altogether, this work presents novel insight into fluid flow speed that can be used to further inform the field. It is our hope that the findings from this dissertation can go towards a more comprehensive treatment of a specific type of brain cancer, glioblastoma.

Glioblastoma is the most common and deadly primary brain tumor with an average survival of 15 months following diagnosis. Characterized as highly infiltrative with diffuse tumor margins, complete resection and annihilation of tumor cells is impossible following current standard of care therapies. Thus, tumor recurrence is inevitable. Interstitial fluid surrounds all of the cells in the body and has been linked to elevated invasion in glioma, which highlights the importance of this understudied fluid compartment in the brain. The primary objective of this dissertation was to identify specific interstitial fluid transport behaviors associated with elevated invasion surrounding glioma tumors. We first describe our methods to measure interstitial fluid flow in the brain using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI), a clinically used, non-invasive imaging modality. We highlight the versatility of the technique and the possibilities that could arise from widespread adoption into existing perfusion-based imaging protocols. Using this method, we examined transport associated with invasion in a murine GL261 cell line. We found that elevated interstitial fluid velocity magnitudes, decreased diffusion coefficients and regions with accumulating flow were significantly associated with invasion. We tested the validity of our invasive trends by extending our analysis to multiple, clinically-relevant tumor locations in the brain. Interestingly, we found invasion did not follow the same trends across brain regions indicating location-specific structures may drive both interstitial flow and corresponding invasion heterogeneities. Lastly, we aimed to manipulate flow by engaging with the meningeal lymphatics, an established pathway for interstitial fluid drainage. Over-expression of VEGF-C in the tumor microenvironment neither enhanced drainage nor altered invasion in comparison to our control, indicating other tumor-secreted growth factors, such as VEGF-A, may play a larger role in mediating flow and invasion. Taken together, by identifying specific transport factors associated with invasion, we may be better equipped to target and treat infiltrative tumor margins, ultimately extending survival in patients diagnosed with this devastating disease. / Doctor of Philosophy / Glioblastoma is the most common and deadly primary brain tumor with an average survival of 15 months following diagnosis. Characterized as highly infiltrative with diffuse tumor margins, complete resection and annihilation of tumor cells is impossible following current standard of care therapies. Thus, tumor recurrence is inevitable. Interstitial fluid surrounds all of the cells in the body and has been linked to elevated invasion in glioma, which highlights the importance of this understudied fluid compartment in the brain. The primary objective of this dissertation was to identify specific interstitial fluid transport behaviors associated with elevated invasion surrounding glioma tumors. We first describe our methods to measure interstitial fluid flow in the brain using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI), a clinically used, non-invasive imaging modality. We highlight the versatility of the technique and the possibilities that could arise from widespread adoption into existing imaging projects. Using this method, we examined transport associated with cancer cell invasion in a mouse tumor cell line. We found that interstitial fluid speeds were elevated while diffusion was decreased in regions of invasion. Further, regions that had interstitial fluid flow congregation were significantly associated with invasion. We tested the validity of these invasive trends by extending our analysis to multiple, clinically-relevant tumor locations in the brain. Interestingly, we found invasion did not follow the same trends across brain regions, indicating location-specific structures may drive both interstitial flow and invasion differences. Lastly, we aimed to manipulate flow by engaging with the meningeal lymphatics, an established pathway for interstitial fluid drainage. Following administration of a meningeal lymphatic-relevant protein, we saw no changes in flow or invasion in comparison to our untreated control, indicating other tumor-secreted proteins may play a larger role in these responses. Taken together, by identifying specific transport factors associated with invasion, we may be better equipped to target and treat infiltrative tumor margins, ultimately extending survival in patients diagnosed with this devastating disease.

The two objectives for this thesis were to 1) validate a bovine luteinizing hormone (LH) ELISA for use in the laboratory and 2) validate interstitial glucose sensors designed for humans for use in lactating dairy cattle. The first experiment required validation of a bovine LH ELISA in order to measure the circulating concentration of LH in the blood of cows in altered thermal and/or metabolic states. Assays from two separate companies were tested. Half of one plate was run at a time resulting in a total of 6 separate analyses (3 plates total). Despite early, promising results, neither LH ELISA could be successfully validated. For many analyses, the standard curves did not even meet the minimal criteria to allow calculation of a formula for determining the concentrations of the unknowns. In analyses where the standard curves were acceptable, the coefficients of variation (CV%) for the unknowns were unacceptable. The second experiment attempted to validate the use of commercially available human interstitial glucose sensors (FreeStyle Libre and Dexcom G6) in lactating dairy cows. Blood glucose concentrations correlated well with sensors secured behind the cow's ear for both FreeStyle Libre (r=0.82) and Dexcom (r=0.88). Unfortunately, however, the absolute relative error's highest value was 47% for the FreeStyle Libre ear. In summary, neither the LH ELISAs nor the interstitial glucose sensors could be validated. / Master of Science / Two separate studies were performed with the purpose of one, measuring a hormone significant to reproduction, Luteinizing Hormone (LH), and two, measuring glucose in interstitial fluid in lactating cows. The first experiment required the use of a commercially available ELISA test to measure LH concentrations. While using radioimmunoassay (RIA) is the preferred method for measuring LH in dairy cattle, an ELISA is an alternative method that is generally more accessible. There was also little published research available illustrating the accuracy of the LH ELISAs. Therefore, we attempted to validate the assays for bovine samples. Despite several attempts, the LH ELISA was unsuccessfully validated. The second study attempted to validate commercially available continuous interstitial glucose sensors designed for humans for use with lactating Holstein cows. Validation of interstitial sensors for use in dairy cattle would decrease the amount of stress and handling when measuring circulating glucose for research, clinical diagnostics and application in industry. While early data suggested that sensors behind a cow's ear may work, further analysis illustrated the sensors were not accurate enough when used on cows. In conclusion, the lab was unsuccessful in proving that continuous interstitial glucose monitors and LH ELISAs could be utilized in the lab.

Introdução: A doença intersticial pulmonar (DIP) é uma forma de acometimento visceral grave pela esclerose sistêmica (ES), correspondendo na atualidade à principal causa de mortalidade pela doença. Atualmente, a tomografia computadorizada de alta resolução pulmonar (TCAR) é considerada o padrão-ouro no seu diagnóstico. Estudos recentes têm proposto diversos algoritmos clínicos para a predição diagnóstica e prognóstica da DIP-ES, objetivando ampliar sua detecção precoce e auxiliar na determinação de sua evolução e prognóstico. Objetivo: Testar os algoritmos clínicos propostos na literatura na predição diagnóstica e prognóstica na DIP-ES, estimar sua prevalência e avaliar a associação da extensão do acometimento pulmonar na TCAR com mortalidade em uma coorte de pacientes com ES. Métodos: Estudo de coorte prospectivo, incluindo 177 pacientes com ES recrutados no período de abril de 2000 a abril de 2009, avaliados através de entrevista, exame físico, exames laboratoriais, provas de função pulmonar e TCAR. Algoritmos clínicos (A, B e C), combinando dados da ausculta pulmonar, radiografia de tórax e capacidade vital forçada (CVF), foram aplicados para o diagnóstico de diferentes extensões da pneumopatia intersticial na TCAR. Curvas de Kaplan-Meier e Regressão de Cox uni e multivariada foram utilizadas para analisar a associação dos algoritmos e da extensão de DIP na TCAR com a mortalidade. Resultados: A prevalência estimada de DIP na TCAR do baseline foi de 57,1% e 79 pacientes (44,6%) morreram em uma mediana de 11,1 anos de seguimento. Para identificação de DIP com extensão ≥10 e ≥20% na TCAR, todos os algoritmos apresentaram uma alta sensibilidade (>89%) e um likelihoodratio negativo muito baixo (<0,16). Para fins prognósticos, sobrevida foi reduzida para todos os algoritmos, com destaque para o algoritmo C, o qual identifica DIP considerando a presença de crepitantes na ausculta pulmonar, alterações na radiografia de tórax ou CVF <80% (HR 3,47; IC 95% 1,62-7,42). Pacientes com doença extensa como proposto por Goh e Wells (extensão >20% na TCAR ou, em casos indeterminados, CVF <70%) apresentam uma significativa redução na sobrevida (HR 3,42; IC 95% 2,12-5,52). Sobrevida não foi diferente entre pacientes com extensão ≥10 ou ≥20% na TCAR e análise de mortalidade em 10 anos sugere que extensão >10% na TCAR apresenta uma boa capacidade preditiva para mortalidade, embora não haja um ponto de corte claro a partir do qual ocorra um maior incremento na mortalidade. Conclusão: Algoritmos clínicos apresentam uma alta sensibilidade e um likelihood ratio negativo muito baixo para o diagnóstico de extensões de DIP com relevância clínica e prognóstica (≥10 e ≥20%) e foram fortemente associados com mortalidade. Assim sendo, a utilização desses algoritmos pode evitar a necessidade de realização de TCAR em alguns casos. / Introduction: Interstitial lung disease (ILD) is a form of severe visceral involvement by systemic sclerosis (SSc) and currently is the primary cause of death by disease. Thoracic high-resolution computed tomography (HRCT) is considered the gold standard for diagnosis. Recent studies have proposed several clinical algorithms to predict the diagnosis of SSc-ILD, aiming to expand its early detection and estimate prognosis. Objective: To test the clinical algorithms to predict the presence and prognosis of SSc-ILD, to estimate the prevalence of SSc-ILD, and to evaluate the association of extent of ILD with mortality in a cohort of SSc patients. Methods: Prospective cohort study, including 177 SSc patients assessed by clinical evaluation, laboratory tests, pulmonary function tests, and HRCT. Clinical algorithms, combining lung auscultation, chest radiography and % predicted forced vital capacity (FVC), were applied for the diagnosis of different extents of ILD on HRCT. Univariate and multivariate Cox proportional models were used to analyze the association of algorithms and the extent of ILD on HRCT with the risk of death using hazard ratios (HR). Results: The prevalence of ILD was 57.1% on baseline HRCT and 79 patients died (44.6%) in a median follow-up of 11.1 years. For identification of ILD with extent ≥10 and ≥20% on HRCT, all algorithms presented a high sensitivity (>89%) and a very low negative likelihood ratio (<0.16). For prognosis, survival was decreased for all algorithms, especially the algorithm C (HR 3.47, 95% CI 1.62-7.42), which identified the presence of ILD based on crackles on lung auscultation, findings on chest X-ray or FVC <80%. Extensive disease as proposed by Goh and Wells (extent of ILD >20% on HRCT or, in indeterminate cases, FVC <70%) had a significantly higher risk of death (HR 3.42, 95% CI 2.12 to 5.52). Survival was not different between patients with extent of 10 or 20% of ILD on HRCT, and analysis of 10-year mortality suggested that a threshold of 10% may also have a good predictive value for mortality. However, there is no clear cutoff above which mortality is sharply increased. Conclusion: Clinical algorithms had a good diagnostic performance for extent of SSc-ILD on HRCT with clinical and prognostic relevance (≥10 and ≥20%), and were also strongly related to mortality. Therefore, they probably could be used to obviate the requirement of HRCT in some cases.

Introdução: A doença intersticial pulmonar (DIP) é uma forma de acometimento visceral grave pela esclerose sistêmica (ES), correspondendo na atualidade à principal causa de mortalidade pela doença. Atualmente, a tomografia computadorizada de alta resolução pulmonar (TCAR) é considerada o padrão-ouro no seu diagnóstico. Estudos recentes têm proposto diversos algoritmos clínicos para a predição diagnóstica e prognóstica da DIP-ES, objetivando ampliar sua detecção precoce e auxiliar na determinação de sua evolução e prognóstico. Objetivo: Testar os algoritmos clínicos propostos na literatura na predição diagnóstica e prognóstica na DIP-ES, estimar sua prevalência e avaliar a associação da extensão do acometimento pulmonar na TCAR com mortalidade em uma coorte de pacientes com ES. Métodos: Estudo de coorte prospectivo, incluindo 177 pacientes com ES recrutados no período de abril de 2000 a abril de 2009, avaliados através de entrevista, exame físico, exames laboratoriais, provas de função pulmonar e TCAR. Algoritmos clínicos (A, B e C), combinando dados da ausculta pulmonar, radiografia de tórax e capacidade vital forçada (CVF), foram aplicados para o diagnóstico de diferentes extensões da pneumopatia intersticial na TCAR. Curvas de Kaplan-Meier e Regressão de Cox uni e multivariada foram utilizadas para analisar a associação dos algoritmos e da extensão de DIP na TCAR com a mortalidade. Resultados: A prevalência estimada de DIP na TCAR do baseline foi de 57,1% e 79 pacientes (44,6%) morreram em uma mediana de 11,1 anos de seguimento. Para identificação de DIP com extensão ≥10 e ≥20% na TCAR, todos os algoritmos apresentaram uma alta sensibilidade (>89%) e um likelihoodratio negativo muito baixo (<0,16). Para fins prognósticos, sobrevida foi reduzida para todos os algoritmos, com destaque para o algoritmo C, o qual identifica DIP considerando a presença de crepitantes na ausculta pulmonar, alterações na radiografia de tórax ou CVF <80% (HR 3,47; IC 95% 1,62-7,42). Pacientes com doença extensa como proposto por Goh e Wells (extensão >20% na TCAR ou, em casos indeterminados, CVF <70%) apresentam uma significativa redução na sobrevida (HR 3,42; IC 95% 2,12-5,52). Sobrevida não foi diferente entre pacientes com extensão ≥10 ou ≥20% na TCAR e análise de mortalidade em 10 anos sugere que extensão >10% na TCAR apresenta uma boa capacidade preditiva para mortalidade, embora não haja um ponto de corte claro a partir do qual ocorra um maior incremento na mortalidade. Conclusão: Algoritmos clínicos apresentam uma alta sensibilidade e um likelihood ratio negativo muito baixo para o diagnóstico de extensões de DIP com relevância clínica e prognóstica (≥10 e ≥20%) e foram fortemente associados com mortalidade. Assim sendo, a utilização desses algoritmos pode evitar a necessidade de realização de TCAR em alguns casos. / Introduction: Interstitial lung disease (ILD) is a form of severe visceral involvement by systemic sclerosis (SSc) and currently is the primary cause of death by disease. Thoracic high-resolution computed tomography (HRCT) is considered the gold standard for diagnosis. Recent studies have proposed several clinical algorithms to predict the diagnosis of SSc-ILD, aiming to expand its early detection and estimate prognosis. Objective: To test the clinical algorithms to predict the presence and prognosis of SSc-ILD, to estimate the prevalence of SSc-ILD, and to evaluate the association of extent of ILD with mortality in a cohort of SSc patients. Methods: Prospective cohort study, including 177 SSc patients assessed by clinical evaluation, laboratory tests, pulmonary function tests, and HRCT. Clinical algorithms, combining lung auscultation, chest radiography and % predicted forced vital capacity (FVC), were applied for the diagnosis of different extents of ILD on HRCT. Univariate and multivariate Cox proportional models were used to analyze the association of algorithms and the extent of ILD on HRCT with the risk of death using hazard ratios (HR). Results: The prevalence of ILD was 57.1% on baseline HRCT and 79 patients died (44.6%) in a median follow-up of 11.1 years. For identification of ILD with extent ≥10 and ≥20% on HRCT, all algorithms presented a high sensitivity (>89%) and a very low negative likelihood ratio (<0.16). For prognosis, survival was decreased for all algorithms, especially the algorithm C (HR 3.47, 95% CI 1.62-7.42), which identified the presence of ILD based on crackles on lung auscultation, findings on chest X-ray or FVC <80%. Extensive disease as proposed by Goh and Wells (extent of ILD >20% on HRCT or, in indeterminate cases, FVC <70%) had a significantly higher risk of death (HR 3.42, 95% CI 2.12 to 5.52). Survival was not different between patients with extent of 10 or 20% of ILD on HRCT, and analysis of 10-year mortality suggested that a threshold of 10% may also have a good predictive value for mortality. However, there is no clear cutoff above which mortality is sharply increased. Conclusion: Clinical algorithms had a good diagnostic performance for extent of SSc-ILD on HRCT with clinical and prognostic relevance (≥10 and ≥20%), and were also strongly related to mortality. Therefore, they probably could be used to obviate the requirement of HRCT in some cases.

Introdução: A doença intersticial pulmonar (DIP) é uma forma de acometimento visceral grave pela esclerose sistêmica (ES), correspondendo na atualidade à principal causa de mortalidade pela doença. Atualmente, a tomografia computadorizada de alta resolução pulmonar (TCAR) é considerada o padrão-ouro no seu diagnóstico. Estudos recentes têm proposto diversos algoritmos clínicos para a predição diagnóstica e prognóstica da DIP-ES, objetivando ampliar sua detecção precoce e auxiliar na determinação de sua evolução e prognóstico. Objetivo: Testar os algoritmos clínicos propostos na literatura na predição diagnóstica e prognóstica na DIP-ES, estimar sua prevalência e avaliar a associação da extensão do acometimento pulmonar na TCAR com mortalidade em uma coorte de pacientes com ES. Métodos: Estudo de coorte prospectivo, incluindo 177 pacientes com ES recrutados no período de abril de 2000 a abril de 2009, avaliados através de entrevista, exame físico, exames laboratoriais, provas de função pulmonar e TCAR. Algoritmos clínicos (A, B e C), combinando dados da ausculta pulmonar, radiografia de tórax e capacidade vital forçada (CVF), foram aplicados para o diagnóstico de diferentes extensões da pneumopatia intersticial na TCAR. Curvas de Kaplan-Meier e Regressão de Cox uni e multivariada foram utilizadas para analisar a associação dos algoritmos e da extensão de DIP na TCAR com a mortalidade. Resultados: A prevalência estimada de DIP na TCAR do baseline foi de 57,1% e 79 pacientes (44,6%) morreram em uma mediana de 11,1 anos de seguimento. Para identificação de DIP com extensão ≥10 e ≥20% na TCAR, todos os algoritmos apresentaram uma alta sensibilidade (>89%) e um likelihoodratio negativo muito baixo (<0,16). Para fins prognósticos, sobrevida foi reduzida para todos os algoritmos, com destaque para o algoritmo C, o qual identifica DIP considerando a presença de crepitantes na ausculta pulmonar, alterações na radiografia de tórax ou CVF <80% (HR 3,47; IC 95% 1,62-7,42). Pacientes com doença extensa como proposto por Goh e Wells (extensão >20% na TCAR ou, em casos indeterminados, CVF <70%) apresentam uma significativa redução na sobrevida (HR 3,42; IC 95% 2,12-5,52). Sobrevida não foi diferente entre pacientes com extensão ≥10 ou ≥20% na TCAR e análise de mortalidade em 10 anos sugere que extensão >10% na TCAR apresenta uma boa capacidade preditiva para mortalidade, embora não haja um ponto de corte claro a partir do qual ocorra um maior incremento na mortalidade. Conclusão: Algoritmos clínicos apresentam uma alta sensibilidade e um likelihood ratio negativo muito baixo para o diagnóstico de extensões de DIP com relevância clínica e prognóstica (≥10 e ≥20%) e foram fortemente associados com mortalidade. Assim sendo, a utilização desses algoritmos pode evitar a necessidade de realização de TCAR em alguns casos. / Introduction: Interstitial lung disease (ILD) is a form of severe visceral involvement by systemic sclerosis (SSc) and currently is the primary cause of death by disease. Thoracic high-resolution computed tomography (HRCT) is considered the gold standard for diagnosis. Recent studies have proposed several clinical algorithms to predict the diagnosis of SSc-ILD, aiming to expand its early detection and estimate prognosis. Objective: To test the clinical algorithms to predict the presence and prognosis of SSc-ILD, to estimate the prevalence of SSc-ILD, and to evaluate the association of extent of ILD with mortality in a cohort of SSc patients. Methods: Prospective cohort study, including 177 SSc patients assessed by clinical evaluation, laboratory tests, pulmonary function tests, and HRCT. Clinical algorithms, combining lung auscultation, chest radiography and % predicted forced vital capacity (FVC), were applied for the diagnosis of different extents of ILD on HRCT. Univariate and multivariate Cox proportional models were used to analyze the association of algorithms and the extent of ILD on HRCT with the risk of death using hazard ratios (HR). Results: The prevalence of ILD was 57.1% on baseline HRCT and 79 patients died (44.6%) in a median follow-up of 11.1 years. For identification of ILD with extent ≥10 and ≥20% on HRCT, all algorithms presented a high sensitivity (>89%) and a very low negative likelihood ratio (<0.16). For prognosis, survival was decreased for all algorithms, especially the algorithm C (HR 3.47, 95% CI 1.62-7.42), which identified the presence of ILD based on crackles on lung auscultation, findings on chest X-ray or FVC <80%. Extensive disease as proposed by Goh and Wells (extent of ILD >20% on HRCT or, in indeterminate cases, FVC <70%) had a significantly higher risk of death (HR 3.42, 95% CI 2.12 to 5.52). Survival was not different between patients with extent of 10 or 20% of ILD on HRCT, and analysis of 10-year mortality suggested that a threshold of 10% may also have a good predictive value for mortality. However, there is no clear cutoff above which mortality is sharply increased. Conclusion: Clinical algorithms had a good diagnostic performance for extent of SSc-ILD on HRCT with clinical and prognostic relevance (≥10 and ≥20%), and were also strongly related to mortality. Therefore, they probably could be used to obviate the requirement of HRCT in some cases.

Kidney failure results in fluid and toxin accumulation within body fluid compartments, contributing to the excess mortality seen in this condition. Such uremic toxins have been measured in plasma, with levels assumed to reflect extraplasmatic concentrations such as in interstitial fluid (ISF). ISF is separated from plasma by nanometre-order microvascular pores; toxins may not circulate “freely” between the two compartments. This work set out to characterise the ISF in uremic subjects, with the hypothesis that there may be differences with plasma. Any such difference may be clinically relevant, owing to the much larger size of the ISF compartment, its proximity to cell metabolic processes, and its expansion in renal impairment.We used a modified microdialysis technique to successfully sample subcorneal ISF of some the uremic toxins (urea, creatinine, urate, phosphate). Reverse iontophoresis (RI) was also used as a non-invasive technique to sample epidermal ISF of urea. Hollow microneedles were developed and their ability to extract ISF tested in CKD patients and controls. The mechanical properties (pressure, volume, permeability) and biochemical composition (proteomic and metabolomic profiles) of the interstitial compartment were also investigated.Microdialysis and RI performed very well as interstitial uremic toxin sampling techniques. Small differences were seen in steady states between ISF and plasma urea, creatinine, phosphate and urate, with slightly lower ISF levels. Dialysis seemed to enhance this difference, with a lag in the clearance of ISF toxins seen in some patients, most remarkable with phosphate. Metabolomic analysis identified several uremic toxins in ISF, whilst proteomics found some significant differences between the two compartments, with toxins like beta-2 microglobulin occurring in ISF only. Microneedle arrays successfully extracted ISF in 68.8% of patients with oedema. Successful extraction of ISF with microneedles occurred mainly in oedematous patients, who were found to have raised interstitial pressures (ISP) and volumes. ISP correlated significantly with body fluid volumes and seemed time-dependent, lower in more chronic oedema. ISP and volumes also correlated with the oedema depitting time (after thumb pressure), a potential novel parameter that probably relates to tissue hydraulic conductivity and hence volume status and fluid mobility within the interstitium.This study demonstrates that interstitial fluid may need to be considered as a separate active compartment in patients with renal dysfunction, with a different “uremic" composition and unique pathophysiological characteristics that cannot be explained by blood compartment based measurements alone. There is a need for more studies, to further characterise this compartment and elucidate its importance.

The most common causes of childhood interstitial lung disease (chILD) are autosomal recessive mutations in the gene encoding ATP Binding Cassette A3 (ABCA3) protein, a lamellar body (LB) associated lipid transporter exclusively expressed within the alveolar epithelial type II cells (AEC2s) in the lung. Instability of primary AEC2s in culture has prevented studies of ABCA3 mutations, resulting in limited understanding of disease pathogenesis. To overcome this challenge, we developed AEC2-like cells from human pluripotent stem cells (PSCs) in vitro, allowing study of normal ABCA3 function and perturbations that result from ABCA3 mutations. To develop an AEC2 model that would recapitulate ABCA3 biology, we targeted human PSC lines with a knock-in GFP fusion reporter (ABCA3:GFP). Differentiations of PSCs into AEC2s (iAEC2s) resulted in exclusive expression of ABCA3:GFP in iAEC2s and intracellular localization to LAMP3+ vesicles, reminiscent of endogenous ABCA3. Moreover, we find these ABCA3:GFP+ iAEC2s express LBs, process surfactant proteins, and secret surfactant lipids, indicative of preserved ABCA3 function. To study the effects of ABCA3 mutations using our model, we generated two sets of PSC reporter lines: 1) two patient-derived iPSC lines carrying rare homozygous E690K and W308R ABCA3 mutations predicted to affect ABCA3 function or trafficking, respectively, and their two syngeneic gene-corrected lines each targeted with the AEC2-specific knock-in fluorescent reporter SFTPCtdTomato; and 2) three syngeneic ABCA3:GFP knock-in iPSC lines encoding wildtype, E690K, or W308R proteins. Directed differentiation of patient iPSCs into iAEC2s revealed attenuated secretion of surfactant-specific lipids, recapitulating clinical findings of surfactant deficiency. Examination of ABCA3 protein trafficking using the ABCA3:GFP fusion reporter revealed retained E690K and W308R mutant ABCA3 protein processing and trafficking compared to the wildtype protein by confocal microscopy and western blot analyses, however mutant iAEC2s exhibited smaller LBs, indicative of defective ABCA3-dependent lipid transport. Bulk RNA sequencing of mutant and gene-corrected SFTPCtdTomato- or ABCA3:GFP-expressing iAEC2s revealed enrichment of the TNF𝛼-NF𝜅B pathway in both W308R and E690K mutant iAEC2s, validated by lentiviral reporter assays and secretion of NF𝜅B-driven cytokines. Thus, we provide insights into how ABCA3 mutations alter AEC2 physiology and developed a platform to study other genetic AEC2 diseases through our ABCA3:GFP reporter system. / 2021-05-26T00:00:00Z

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 5 uppsatser.

In der kontroversen Diskussion um die unklare Ätiologie der Appendizits wird oft eine Motilitätsstörungen angeführt. Die Interstitial cells of Cajal sind bedeutend für die Motilität und die Entstehung der Peristaltik im menschlichen Kolon. Bei einigen Motilitätsstörungen des Darmes wurde eine Rarifizierung dieser Zellen beobachtet. Die ICC wuden noch nie in der Appendix vermiformis beschrieben.In dieser Arbeit wurden erstmals die ICC in der Appendix mittels einer immunhistochemischen Färbung durch einen maus-monoklonalen Antikörper ( NCL- cKit) nachgewiesen sowie analysiert. Es konnten keine Subgruppen IC-SMP und IC-MP in der Appendix nachgewiesen werden. Die IC-LM zeigten sich reduziert im Vergleich zum Kolon. Die IC-CM konnten zahlreich und regelmäßig dargestellt werden. Eine unterschiedliche Verteilung bzw. Dichte der ICC in der normalen Appendix, der akut und chronisch entzündeten Appendizits konnte nicht nachgewiesen werden.Schlussfolgernd und in Übereinstimmung mit den Beobachtungen anderer Autoren besitzt die Appendix eine reduzierte Motilität und eine physiologische Koprosthase, die aber allein nicht zu einer Entzündung führt. Erst unter dem Einfluss der aus der Literatur bekannten Kofaktoren wird die Koprosthase verstärkt. Erst dies führt zu einer Alteration der Schleimhaut und zur Appendizitis. / The aetiology of the childlike appendicitis is not generally known, but a motility disorder is discussed. The Interstitial cells of Cajal (ICC) are important for the motility and the development of the peristalsis of the colon. In some motility disorders the ICC are abnormaly distributed. The ICC of the human vermiform appendix has never been examined before. We proved and analysed the ICC of the appendix with the mous-monoclonal antibody against c-kit, (NCL-cKit). We could not identify subtypes of ICC, as IC-SMP or IC-MP in the appendix. The IC-LM were reduced compared to the colon. The IC-CM were numerously and regularly distributed. There were no differences in the reduced incidence of ICC between normal vermiform appendix, acute inflamed and chronic inflamed appendicitis.In conclusion and conformance with other observations the appendix has a physiological motility disorder and koprosthasis. Only if some influences of presumably additional cofactors (e.g. inflamation, lymphoid hyperplasia, obstruction), the koprosthasis is intensified, the mucosa is irritated and the appendicitis is developed.