Endothelial Cell Protection in Ischemia/Reperfusion Injury: Investigating the Role of the Glycocalyx and the Plasma Cascade Systems
(PI: Robert Rieben)
Ischemia/ Reperfusion injury (IRI) refers to tissue damage that can occur after restoration of blood flow in a previously ischemic area, examples include myocardial infarction or also organ transplantation. A key event in IRI is activation of endothelial cells (EC) leading to a dysregulation of plasma cascade systems and vascular leakage. Both the complement system and the endothelial glycocalyx are important players in vascular homeostasis and complement activation as well as glycocalyx damage have been observed in IRI. We want to understand how EC and their glycocalyx contribute to the maintenance of vascular integrity which could help identify new therapeutic targets in the field of IRI. To investigate this, we use a unique 3D microfluidic model established in our lab which consists of round-section, vessel-like microfluidic channels containing EC exposed to pulsatile flow to reproduce physiological conditions in vitro. This project provides valuable fundamental research that is much needed in the field of IRI.
Developing a next-generation targeted anti-fibrotic therapy for heart failure in a porcine model
(PI: Robert Rieben)
Acute myocardial infarction (AMI) is the most severe manifestation of coronary artery disease. One of the treatment for AMI consists in percutaneous coronary intervention, aiming at restore tissue perfusion. However, as a consequence, ischemia/reperfusion (I/R) injury occurs, possibly increasing the myocardial necrotic area. During post-infarction tissue remodelling, fibrotic tissue will develop. Not contributing to the pump function of the heart, it will lead to heart failure development.
The aim of this trial is to test a chemical compound targeting fibrosis by inhibiting the long non-coding RNA (lncRNA). Wisper acts binding to a pleiotropic master regulator of fibrosis, TIA1 cytotoxic granule associated RNA binding protein-like 1 (TIAR), stimulating its nuclear translocation and promotion of pro-fibrotic target gene transcription, specifically in the heart. Previous studies in vivo murine model of myocardial infarction, showed that inhibition of Wisper using an antisense oligonucleotide reduced cardiac fibrosis by 70% (Micheletti et al., 2017).
Antisense oligonucleotide (ASO) therapeutics are injectable synthetic single-stranded deoxynucleotide polymers that are designed complementary to an RNA or DNA sequence. In this trial we aim to apply two well-established ASO chemistry platforms on top of a standard phosphorothioate-modified backbone in Göttingen minipigs undergoing AMI.
The therapeutic approach that will be explored in this study could be the first disease-modifying drug for heart failure directly addressing cardiac fibrosis in a large animal model. Moreover, due to the paucity of information about pain in minipigs and especially visceral pain, despite their widespread use in cardiovascular biomedical research, a satellite study will be conducted with the aim at evaluating pain in minipigs undergoing AMI.
Site-specific immunosuppression for long-term maintenance of vascularized composite allotransplantation: validation of efficacy and safety in a clinically relevant large animal model
(PI: Radu Olariu, Co-Pi: Robert Rieben)
Vascularized composite allotransplantation (VCA), such as hand-transplantation, has the potential to restore esthetic and function in patient that suffered severe injuries. However, adverse effects of chronic high-dose immunosuppression regimens strongly limit the access to procedures in the clinic. Unlike most solid organ transplants, VCA offer unique opportunities for delivery of immunosuppressive medications directly to the graft. Recently, we developed enzyme-responsive tacrolimus-encapsulated hydrogels (TGMS-TAC) as an “on demand” drug delivery system (DDS) that titrates the amount of drug released in response to inflammation. We proved that a single injection of TGMS-TAC increased graft survival in a rat hind limb transplant model. Moreover, we investigated the long-term outcomes using the same model demonstrating long-term effectiveness and improved pharmacological, toxicological and immunological profile of site-specific immunosuppression. We have also developed an in situ forming implant loaded with rapamycin (Rapa-ISFI) demonstrating that this DDS successfully promotes immunoregulation trough mixed chimerism and donor-specific Treg induction and establishment of peripheral tolerance and long-term acceptance of VCA. Overall, in this project we will provide clear-cut data on the feasibility and validity of DDS-based approaches in a model relevant to clinical human VCA, filling the gap between basic research developments and clinical application and paving the way for human clinical trial.