Publications by authors named "Anja Helmer"
The advent of normothermic, ex-situ heart perfusion (ESHP) enables new options for evaluation of cardiac grafts. Donation after circulatory death (DCD) is a promising solution to improve heart transplantation rates, but current ESHP evaluation approaches are recognized as suboptimal for DCD grafts. We aimed to develop a vascular function test for cardiac graft assessment during ESHP using a porcine model of DCD.
View Article and Find Full Text PDFObjectives: Donation after circulatory death provides excellent patient outcomes in heart transplantation; however, warm ischaemic graft damage remains a concern. We have reported that a brief period of hypothermic oxygenated perfusion prior to normothermic reperfusion improves graft recovery in a rat model. Here we investigated the cardioprotective benefits and mechanisms of this approach compared to the current clinical standard in a large animal model.
View Article and Find Full Text PDFArticle Synopsis
- This study explores the immune rejection of cartilage in vascularized composite allotransplantation (VCA), which is vital for restoring motor function in joint transplants.
- Using a swine model, researchers analyzed tissue samples from grafts that experienced severe skin rejection and found evidence of immune attacks on cartilage but with less severity than skin and muscle.
- The findings indicate that cartilage is not immune from rejection in VCA, showing significant immune response activity, including markers of cell death, although it endures milder inflammation compared to other tissues.
Article Synopsis
- The current standard for preventing rejection in vascularized composite allotransplantation (VCA) uses systemic immunosuppression, which poses significant side effects, leading to interest in local immunosuppression methods.
- Researchers investigated a local drug delivery system for tacrolimus (TGMS-TAC) to reduce toxicity and enhance graft survival, showing promising results in a porcine model, although some rejection signs were noted.
- Results indicated that while systemic immune responses remained stable, local tissue analysis revealed infiltration of immune cells and involvement of neutrophil extracellular traps (NETs) in the rejection process, highlighting the need for better understanding of VCA graft rejection mechanisms.
Article Synopsis
- Vascularized composite allotransplantation (VCA) is a promising technique for restoring limbs or facial features but struggles with high rejection rates due to immune responses.
- Researchers used pig models to study immune rejection by analyzing tissue samples and gene expression, comparing those with moderate and severe rejection to healthy controls.
- Findings showed upregulation of genes linked to innate immunity and immune responses, particularly involving CD8 T cells and macrophages, providing insights for improving VCA outcomes.
Heart transplantation with donation after circulatory death (DCD) provides excellent patient outcomes and increases donor heart availability. However, unlike conventional grafts obtained through donation after brain death, DCD cardiac grafts are not only exposed to warm, unprotected ischemia, but also to a potentially damaging pre-ischemic phase after withdrawal of life-sustaining therapy (WLST). In this review, we aim to bring together knowledge about changes in cardiac energy metabolism and its regulation that occur in DCD donors during WLST, circulatory arrest, and following the onset of warm ischemia.
View Article and Find Full Text PDFResearch Question: Does high-dose gonadotrophin stimulation have an effect on oocyte and early-stage embryo development?
Design: This was a retrospective study including 616 natural cycle IVF (NC-IVF) and 167 conventional IVF (cIVF) cycles. In total, 2110 oocytes were retrieved and analysed in fresh cycles. In NC-IVF, only human chorionic gonadotrophin was applied to trigger ovulation.
Introduction: Timing of ovulation triggering is essential in infertility treatments including treatments based on natural menstrual cycles. However, data on follicle size and oestradiol (E2) concentration are limited. Therefore, the model of natural cycle IVF (NC-IVF) was applied to provide more detailed information on these parameters to better schedule the optimal time for triggering ovulation.
View Article and Find Full Text PDFIntroduction: Endometrial thickness <8 mm is related with lower pregnancy rates. This raises the question if endometrial thickness can be increased by gonadotropin stimulation to increase estradiol (E2) concentration and if such an artificial thickening of the endometrium has an effect on implantation. A model to address this question is the comparison of endometrial thickness and outcome parameters in conventional gonadotropin stimulated IVF (cIVF) compared to unstimulated natural cycle IVF (NC-IVF).
View Article and Find Full Text PDF