We assessed potential mechanisms that may jeopardize skeletal muscle perfusion during surgery leading to adverse outcomes including muscle injury and flap hypoxia. In craniotomy patients, we observed an increase in serum lactate and creatine kinase and urine myoglobin; indicative of muscle damage. The early rise in lactate correlated with elevated BMI, suggesting that obesity caused tissue compression and muscle ischemia. In our rodent model, we investigated the effects of flap preparation and phenylephrine on muscle perfusion by assessing microvascular blood flow and tissue PO2. Phenylephrine reduced muscle blood flow by ~20%, yet increased PO2 by ~10% suggestive of decreased O2 metabolism. At baseline, muscle flap blood flow was reduced by ~50% while PO2 was severely reduced ~80% (~5 torr) suggesting that flap perfusion was attenuated and O2 metabolism was increased. Phenylephrine infusion further reduced muscle flap perfusion. These data demonstrate multiple mechanisms by which muscle perfusion is jeopardized during surgery.

Die kardiale Magnetresonanztomographie (MRT) ermöglicht nach einem akuten Myokardinfarkt (AMI) die Visualisierung und Quantifizierung der Myokardschädigung anhand verschiedener Parameter wie Ejektionsfraktion (EF), Infarktgröße, Mikrovaskuläre Obstruktion (MO) und „Myocardial Salvage Index“ (MSI). Anhand dieser MRT-Marker kann das Risiko für kardiovaskuläre Komplikationen eingeschätzt werden, was für die Weiterversorgung des Patienten sowie für die kardiologische Forschung von großem Interesse ist. In dieser Arbeit wurde die prognostische Relevanz der MRT-Parameter erstmals in einer großen, multizentrischen Studie untersucht. Zudem sollte unter den vier genannten MRT-Markern derjenige mit der größten prognostischen Aussagekraft ermittelt werden. Dazu wurden 795 Patienten aus der AIDA STEMI Studie einer MRT unterzogen und dann zwölf Monate lang im Hinblick auf den kombinierten Endpunkt „Major Adverse Cardiac Events“ (MACE; bestehend aus Tod, Reinfarkt und Klinikaufnahme wegen Herzinsuffizienz) nachbeobachtet. Die Ergebnisse belegen, dass die genannten MRT-Parameter prognostisch relevant sind und insbesondere die MO und die Infarktgröße einen Einfluss auf die Prognose ausüben, welcher über den Wert etablierter klinischer Risikomarker hinausgeht. Herausragende Bedeutung kommt dabei der MO zu, welche nach multivariater Analyse der potenteste MRT-Prädiktor für kardiovaskuläre Ereignisse ist. Somit sollten die MRT-Parameter in kommenden kardiologischen Studien als Surrogatmarker für klinische Endpunkte berücksichtigt werden. Zudem könnten sie für den klinischen Alltag die Möglichkeit bieten, die Patientenversorgung enger an die individuelle Prognose anzupassen.

The main objective of this study was research on biomarkers used in both diagnosis and therapy of diabetic complications. The main focus of our work came to be on one of these biomarkers - glycemic variability (GV). High GV is linked with more frequent occurance of hypoglycemia. There are even indications it might contribute to development of diabetic complications. With modern technology - continuous glucose monitoring (CGM), we are now able to reliably describe, calculate and reduce GV. So far it is unclear whether increased GV can contribute to the development of microvascular complications (MVC) in type 1 diabetes (T1D). Studies published so far have assessed GV primarily from routine self-monitoring of blood glucose (SMBG) using glucometers. In the light of this uncertaity, the first part of this work compares GV calculated from CGM with the presence of MVC in T1D patients. GV calculated from CGM, but not from SMBG, proved to be significantly higher in T1D patients with MVC, even though there was no significant difference in glycated hemoglobin (HbA1c). This finding supports the hypothesis that higher GV is related to higher risk of MVC and that HbA1c does not describe diabetes control completely. Moreover, it was shown that GV calculated from SMBG is insufficient. There is still no fully...

A la suite d'une lésion nerveuse périphérique, de multiples altérations cellulaires et moléculaires participent à la régénération physiologique du nerf, mais induisent dans certains cas le développement d'une cicatrisation dysfonctionnelle et l'apparition d'une douleur neuropathique chronique. La régulation de la perméabilité vasculaire endoneurale du nerf lésé joue un rôle essentiel dans ces phénomènes de cicatrisation nerveuse, via notamment l'infiltration locale d'immunocytes. L'objectif de ce travail était d'étudier le rôle spécifique de l'altération de la barrière hémato-nerveuse (BHN) au niveau du site lésé dans le développement des douleurs neuropathiques périphériques post-traumatiques. Nous avons montré à l'aide de modèles de constriction chronique du nerf sciatique et/ou infra-orbitaire que la disruption précoce de la BHN est un évènement clé de la neuropathie, favorisant l'infiltration locale de substances algogènes et d'immunocytes induisant une neuroinflammation, une sensibilisation périphérique et la neuropathie. L'altération des voies de signalisation Sonic Hedgehog, Wnt/?-caténine et TLR4 au niveau des cellules endothéliales endoneurales, favorise cette disruption en diminuant la synthèse des protéines de jonctions serrées, molécules clés de l'intégrité de la BHN. De plus, l'implication différentielle de ces voies dans des modèles de neurite et de neuropathie apporte un éclairage nouveau à la transition phénotypique entre neurite et neuropathie : alors que la neurite s'accompagne d'une perméabilité vasculaire endoneurale réversible, la neuropathie pourrait être considérée comme une pathologie de la perméabilité vasculaire chronique irréversible. / Following peripheral nerve injury, multiple cellular and molecular alterations occur within the nerve’s parenchyma, participating in physiological healing of the nerve, but can also lead to the development of dysfunctional nerve healing, translating as chronic neuropathic pain. The regulation of endoneurial microvascular permeability within the injured nerve plays a pivotal rôle in physiological and pathological nerve healing, notably via the local infiltration of pro-regenerative immunocytes. The main goal of this work was to study the specific role of local blood-nerve barrier disruption in the development of painful post-traumatic peripheral neuropathy. In sciatic nerve and/or infra-orbital nerve chronic constriction injury models, we showed that early disruption of the blood-nerve barrier is a key event in the development of neuropathy, allowing local infiltration of algogenic substances and immunocytes within the nerve’s parenchyma, responsible for local neuroinflammation, peripheral sensitization and peripheral neuropathic pain development. Among the homeostatic regulatory mecanisms of this barrier, the alteration of Sonic Hedgehog, Wnt/β-catenin and TLR4 signaling pathways in endoneurial endothelial cells, mediates the disruption of the blood-nerve barrier by downregulating key tight-junction proteins. Furthermore, the differential implication of these signaling pathways in models of neuritis and neuropathy shed light on the phenotypical transition between neuritis and neuropathy : As neuritis is associated with reversible endoneurial vascular permeability, neuropathy could be considered a disease of irreversible chronic vascular permeability.

La drépanocytose est une hémoglobinopathie essentiellement connue pour ses répercussions hématologiques, hémodynamiques et vasculaires chez les patients homozygotes (SCA). Bien que ces sujets présentent une intolérance à l'effort, la littérature est très pauvre concernant les répercussions musculaires de la maladie. Ce travail doctoral nous a permis de caractériser pour la première fois les répercussions structurales, énergétiques et microvasculaires du muscle d’hommes (étude 1) et de femmes (étude 2) drépanocytaires par rapport à des sujets SCT et contrôles (CON). Nos analyses histologiques et biochimiques ont mis en évidence chez les sujets SCA masculins une amyotrophie qui explique au moins en partie la diminution de l’IMC des SCA au dépend de la masse maigre. Nous avons également observé l’altération de plusieurs indices du métabolisme oxydatif (CS, β-HAD et COx) qui pourrait relever de la restriction d’approvisionnement et d’utilisation tissulaire en O2 et expliquer en partie l’intolérance à l’effort. Enfin, un remodelage microvasculaire caractérisé par une raréfaction, une moindre tortuosité et une fragilisation des microvaisseaux a également été démontré. Ce remodelage microvasculaire pourrait contribuer à limiter le risque d’enclavement des hématies falciformées et ainsi réduire les risques de vaso-occlusions. La recherche de ces différents stigmates dans le muscle de la population féminine homologue a rapporté un remodelage musculaire similaire à celui observé chez les hommes SCA, mais ce dernier semble atténué, suggérant un effet genre / Sickle cell anemia (SCA) is a hemoglobinopathy particularly known for its hematologic, hemodynamics and vascular repercussions. Although SCA patients are exercise intolerant, no studies have looked at muscle repercussions. We assessed repercussions of sickle cell anemia on skeletal muscle and its microvasculature in men (study 1) and women (study 2) for the first time. Our results showed that men with SCA displayed an amyotrophy which can at least partly explain the decrease of BMI at the expense of lean muscle mass. We also pointed out a decrease in muscle oxidative capacities (CS, β-HAD and COx) which could result from O2 supply and utilization disorders and partly explain their exercise intolerance. Finally, a microvascular remodeling characterized by a rarefaction, a decrease in microvessel tortuosity and a microvessel weakening was also highlighted. This remodeling could contribute to maintain local blood flow and reduce risks of entrapment of sickle red blood cells in the microvasculature, hence reducing vaso-occlusive risks. Muscle repercussions on a similar female population testified of the same muscle remodeling as the one observed in men with SCA, but this latter seemed to happen at a lesser extent in women with SCA, suggesting a gender effect

Angina pectoris är bröstsmärta orsakat av myokardischemi, till följd av kranskärlsjukdom med eller utan stenoser eller icke kranskärlsjukdom. Arbetsprov är den vanligaste undersökningen för angina pectoris. Diffusa symtom och angina pectoris varianter utan stenoser med låg sensitivitet för elektrokardiografi (EKG) sänker den diagnostiska säkerheten i arbetsprov på kvinnor. Litteraturstudiens syfte var att utreda om hemodynamiska parametrar och riskbedömning med Pre-test sannolikhet (PTP) samt Dukes Löpbands Index (DTS, Dukes Treadmill Score) kan öka den diagnostiska säkerheten i arbetsprov på kvinnor. Inklusionskriterierna var vetenskapligt granskade kliniska studier på engelska, med information om etiskt godkännande eller samtycke. Snowballing metoden, PUBMED, MEDLINE och CINAHL användes. Studier som inkluderades i resultatet granskades återigen och jämfördes med varandra. Hemodynamiska parametrar, PTP och DTS ökar den diagnostiska säkerheten i arbetsprov på kvinnor. Denna diagnostiska säkerhet beror dock också på PTP metod, PTP riskgrupp, etnicitet och angina pectoris variant. Vidare forskning behövs om etnicitetspecifika PTP metoder, mekanismen bakom blodtrycksreaktionen, DTS på icke kranskärlsjukdomar samt metoder som kan skilja mellan olika icke kranskärlsjukdomar. Utan studier om Systematic COronary Risk Evaluation (SCORE) och Diamond Forrester Score (DFS) samt deras påverkan på arbetsprov, kan inte resultatet i litteraturstudien generaliseras till arbetsprov i Sverige. / Angina pectoris is chest pain and myocardial ischemia due to Coronary Artery Disease (CAD) or Non-Coronary Artery Disease (non-CAD). Exercise stress test (EST) is the most common diagnostic procedure for angina pectoris. Non-CAD, low sensitivity for exercise electrocardiography (ex-ECG) and diffuse symptoms lower the diagnostic accuracy for females. This review’s aim was to study whether haemodynamic parameters and risk stratifications with Pre-test probability (PTP) or Duke Treadmill Score (DTS) improves the diagnostic accuracy of EST for females. Inclusion criterions were English peer reviewed, clinical studies with mentioned ethical approval or consent. Snowballing, PUBMED, MEDLINE and CINAHL were used. Articles that were included in the results, were reviewed once again, and compared to one another. Hemodynamic parameters, PTP and DTS increase the diagnostic accuracy of EST in women. This diagnostic accuracy depends on PTP method, risk group, ethnicity, and angina pectoris variant. Further research regarding ethnic specific PTP methods, mechanism behind the blood pressure reaction, DTS for diagnosis of non-CAD and methods for differentiation of subtypes of non-CAD, would be valuable. Without studies about the Systematic Coronary Risk Evaluation (SCORE), Diamond Forrester Score (DFS), and their impact on ex-ECG, the result of this review cannot be generalized to ex-ECG in Sweden.

La transplantation pulmonaire est depuis une vingtaine d’années une option thérapeutique valide pour une grande variété de pathologies pulmonaires au stade terminal. Malgré les progrès réalisés ces dernières années en matière de traitement immunosuppresseur, les rejets restent une cause majeure de la perte du greffon. Plusieurs études ont souligné l'importance du rejet aigu comme un facteur contributif important à l’évolution de la dysfonction chronique du greffon (ou CLAD) et, in fine, à la perte du greffon. Par conséquent, des outils diagnostiques fiables de rejet aigu s’imposent pour mieux prévenir le CLAD. Dans notre première étude, nous avons évalué les marqueurs tissulaires de rejet aigu humoral (RAH) pulmonaire. Nous avons montré ainsi que les lésions histologiques dont l’inflammation microvasculaire ne sont pas spécifiques et le marquage C4d est un marqueur utile pour confirmer le diagnostic de RAH. Dans un second temps, nous avons étudié en cytométrie de flux la polarisation des macrophages obtenus par lavage bronchiolo-alvéolaire (LBA) chez des patients transplantés avec et sans rejet. Nos résultats montrent les limites des marqueurs membranaires (HLA-DR et CD206) dans l’évaluation de l’état de polarisation des macrophages au cours des rejets. Ce travail montre l’intérêt des marqueurs tissulaires, en particulier le marquage C4d, dans le suivi des patients transplantés pulmonaires et souligne la nécessité d’identifier des marqueurs appropriés et utilisables en cytométrie de flux pour avancer sur l’état de polarisation des macrophages alvéolaires. / Lung transplantation is considered as a valid therapeutic option for patients with end-stage lung disease. Despite considerable progress in immunosuppressive therapy, allograft rejection remains a major cause of graft loss. Multiple studies have highlighted the importance of acute rejection as an important risk factor for the development of chronic lung allograft dysfunction (CLAD) leading to graft failure. Therefore, the improvement in the diagnosis of acute rejection represents a major challenge to prevent CLAD. In this study, we evaluated the tissue markers of acute antibody-mediated rejection (AMR) in lung transplantation. In our experience, the histopathologic findings including the microvascular inflammation in pulmonary AMR are not specific and C4d staining is a useful marker to confirm the diagnosis of AMR. Secondly, we investigated by flow cytometry the polarization of alveolar macrophage obtained by bronchoalveolar lavage (BAL) from lung transplant patients with and without acute rejection. Our results show the limits of surface markers (CD206 and HLA-DR) in the evaluation of alveolar macrophage polarization. This study shows the interest of tissue markers, especially the C4d staining, in monitoring of lung transplant patients and highlights the need to identify appropriate and available markers for future studies of alveolar macrophage polarization by flow cytometry.

The aim of this thesis is to contribute to the clarification of the pathogenesis of chronic complications of diabetes mellitus. The main goal of the research was glycaemic variability, its contribution to the activation of oxidative stress and its possible role in the process of advanced glycation, all beyond the scope of persistent hyperglycaemia itself. Another aim of the work is to contribute to the clarification of a possible relationship between glycaemic variability and vascular complications of diabetes. We were the first to describe the association between the concentrations of reactive aldehydes formed during lipid peroxidation and disorders of skin microvascular reactivity in patients with type 1 diabetes (DM1). Elevated markers of oxidative stress were found in this group, furthermore during the 3 years of follow-up higher plasma antioxidant activity was observed. These findings were not dependent of the method of glucose monitoring and glucose variability, which was lower in a subgroup of patients using real-time continuous glucose monitoring (rt-CGM), compared to a subgroup using conventional glucometers. However, it is clear, that hyperglycaemia alone induces increased oxidative stress in patients with diabetes. Simultaneously we observed the opposite process of oxidative stress...

Peanut skins are a low-value byproduct of peanut blanching operations. They have been shown to contain significant levels of phenolic compounds with demonstrated antioxidant properties. The effects of two types of extraction methods: solid-liquid extraction (SLE) and microwave-assisted extraction (MAE) on the recovery of phenolic compounds from peanut skins were investigated. Response surface methodology was used to optimize extraction conditions based on total phenolic content (TPC), ORAC (oxygen radical absorbance capacity) activity and <i>trans</i>-resveratrol content. The protective effect of peanut skin extracts (PSE) against hydrogen peroxide (H₂O₂)-induced oxidative stress in human brain microvascular endothelial cells (HBMEC) and the effect of PSE on lipid oxidation in commercial peanut butter were also evaluated. In the SLE method, EtOH was found to be the most efficient extraction solvent followed by MeOH, water and EA. Despite EtOH extracts having a higher TPC, samples extracted with MeOH demonstrated slightly higher ORAC activity. Resveratrol was identified in MeOH extracts but was not found in EtOH, water or EA extracts. In the MAE procedure, the maximum predicted TPC under the optimized conditions was 144 mg phenols/g skins compared to 118 mg/g with SLE. The maximum predicted ORAC activity was 2789 μmol TE/g as opposed to 2149 μmol TE/g with the SLE method. MAE was able to extract more phenolic compounds (with higher antioxidant activity) in a faster time than the SLE procedure. In addition, resveratrol was identified in PSE derived from MAE although at relatively low levels. PSE were found to have some protective effects against oxidative stress in HBMEC. Higher doses of PSE appeared to have a slightly cytotoxic effect. However, the data were highly variable which made it difficult to arrive at any definitive conclusions regarding the potential benefits of PSE in preventing oxidative damage to cells. In the PB experiment, hexanal levels over the storage period were not high enough for the samples to be considered oxidized. However, hexanal values of PB samples treated with PSE were lower than the control throughout storage, which suggests that PSE may provide some protection against oxidation of PB. / Ph. D.

No description available.