<p>Clinical islet transplantation is an emerging procedure to cure type 1 diabetes. The graft is implanted by infusion into the liver through the portal vein. A major obstacle that still needs to be overcome is the requirement for islets from multiple donors to achieve insulin independence. </p><p>An innate inflammatory reaction, the IBMIR, is elicited when islets are exposed to blood. The IBMIR has been described as a clotting reaction culminating in disruption of islet morphology and is a plausible cause for loss of tissue during the early post-transplant period. </p><p>In this thesis, the underlying mechanisms of the IBMIR were characterized. The IBMIR was for the first time demonstrated in patients undergoing an islet transplant, and a number of clinically applicable strategies to limit this reaction were identified.</p><p>The thrombin inhibitor melagatran completely blocked the IBMIR in an <i>in vitro</i> tubing blood loop system, indicating that thrombin is the driving force in the reaction. Interestingly, islets were shown to produce and secrete tissue factor (TF), the physiological trigger of coagulation. Inactivated FVIIa, a specific inhibitor of TF, successfully blocked initiation of the IBMIR. An alternative approach to limit the IBMIR was to pre-treat islets in culture prior to transplantation. Nicotinamide added to the culture medium effectively decreased the level of TF in human islets. Infiltration of immune cells, also a part of the IBMIR, was characterized in detail. The predominant cell types infiltrating the islets were neutrophilic granulocytes and, to a lesser degree, monocytes. Both cell types may exert direct cytotoxic effects, and the antigen-presenting monocytes may also be important for directing the specific immune system to the site of inflammation. </p><p>These findings have provided new insight into the nature of the IBMIR and offer several new strategies to improve the outcome of clinical islet transplantation.</p>

Clinical islet transplantation is an emerging procedure to cure type 1 diabetes. The graft is implanted by infusion into the liver through the portal vein. A major obstacle that still needs to be overcome is the requirement for islets from multiple donors to achieve insulin independence. An innate inflammatory reaction, the IBMIR, is elicited when islets are exposed to blood. The IBMIR has been described as a clotting reaction culminating in disruption of islet morphology and is a plausible cause for loss of tissue during the early post-transplant period. In this thesis, the underlying mechanisms of the IBMIR were characterized. The IBMIR was for the first time demonstrated in patients undergoing an islet transplant, and a number of clinically applicable strategies to limit this reaction were identified. The thrombin inhibitor melagatran completely blocked the IBMIR in an in vitro tubing blood loop system, indicating that thrombin is the driving force in the reaction. Interestingly, islets were shown to produce and secrete tissue factor (TF), the physiological trigger of coagulation. Inactivated FVIIa, a specific inhibitor of TF, successfully blocked initiation of the IBMIR. An alternative approach to limit the IBMIR was to pre-treat islets in culture prior to transplantation. Nicotinamide added to the culture medium effectively decreased the level of TF in human islets. Infiltration of immune cells, also a part of the IBMIR, was characterized in detail. The predominant cell types infiltrating the islets were neutrophilic granulocytes and, to a lesser degree, monocytes. Both cell types may exert direct cytotoxic effects, and the antigen-presenting monocytes may also be important for directing the specific immune system to the site of inflammation. These findings have provided new insight into the nature of the IBMIR and offer several new strategies to improve the outcome of clinical islet transplantation.

Metabolism is the sum of all chemical processes with the purpose to maintain life, as well as enable reproduction, in a living organism. Through the study of metabolism, increased understanding of pharmacological mechanisms and diseases can be achieved. This thesis describes several ways of doing so, including targeted analysis of selected metabolites and investigations of systematic metabolic differences between selected groups through pattern recognition. A method for exploring metabolic patterns in urine samples after intake of coffee or tea was developed. The methodology was later used with the aim to find biomarkers for prostate cancer and urinary bladder cancer. Furthermore, a fully automated quantitative method was developed for concentration measurements of the double prodrug ximelagatran and its metabolites in pig liver. The method was then used to study the roll of active transporters in pig liver cells. Moreover, a fundamental study was conducted to investigate how monitoring of small, doubly charged analytes can improve the limit of detection and precision in a quantitative method. The techniques used for the experiments were liquid separation coupled to electrospray mass spectrometry. Extra efforts were made to make the separation and the ionization as compatible as possible to each other for increased quality of the collected data.