Title:
Medically Licensed Mesenchymal Stem Cells for Acute Respiratory Distress Syndrome.
Aims:
The purpose of this project was to validate the use of human adult, bone-marrow derived, mesenchymal stem cells (MSC) produced at the Centre for Cell Manufacturing ireland (CCMI) in acute respiratory distress syndrome (ARDS) models. This project aimed to:
A) Validate CCMI production techniques through proving retained efficacy of the medical grade (GMP) cell product.
B) To validate that a GMP grade MSC is as efficacious in treating ARDS in pre-clinical models as the traditional laboratory grade MSC.
Results:
In a battery of in vitro tests, we demonstrated that both Fresh and Frozen MSC have an anti-inflammatory nature when added directly to lung epithelial cells This finding could be reproduced utilising culture medium harvested from the Fresh MSC ("conditioned medium"), indicating the MSC mechanism of action is, at least in part, via secreted, contact independent, factors. Pre-stimulation of Fresh MSCs with inflammatory cytokine, to simulate the inflammatory environment found in the ARDS patient, enhanced anti-inflammatory potential.
The ARDS models employed for pre-clinical testing of the MSC were the ventilator induced lung injury (VILI) and pneumonia models. For VILI, a test animal is subject to a damaging ventilator regimen to simulate the high pressures often required to successfully ventilate patients with underperforming lungs. For pneumonia, a bacterial infection is established in the lung, a common causative agent of this disease. Treatment with both Fresh and Frozen MSCs improved arterial blood oxygenation in VILI ARDS, a major finding demonstrating significant improvement of the lung's primary function: getting oxygen into the blood. The number of inflammatory cells found in the lung airspace was dramatically reduced. Fresh and Frozen MSC were equally therapeutic in this regard. The amount of fluid in the lungs was also significantly reduced by either MSC therapy. Inflammatory protein concentrations in the lung were reduced by either MSC formulation, as was lung tissue structure, with more open airways when compared to vehicle controls.
Of extreme clinical relevance, these MSC administrations were successful 6 hours after the onset of recognizable VILI injury, proving a rescue, i.e. non-prophylactic, effect.
MSC intervention for pneumonia ARDS proved more challenging, with a number of injury parameters improved with larger doses of MSC, but with arterial oxygenation enhancement not reproduced with cryofrozen cells when compared with freshly harvested MSC. We are continuing to examine this injury model, using additional donor sources processed by the CCMI and using efficacy enhancement techniques such as those explored in the VILI model.
Conclusions:
Allogeneic bone-marrow derived MSCs manufactured by the Centre for Cell Manufacturing Ireland performed well in models of VILI ARDS. This therapeutic benefit was independent of whether the MSCs were administered from continuous culture or directly from cryofrozen aliquot. Effects could be enhanced through pre-activation methods and functioned after onset of injury. Modest improvement were observed in pneumonia ARDS, with clear pathways identified towards improvement of effect.
Possible impacts:
We are delighted to have validated the CCMI's MSC product for lung therapeutic applications, and the supporting data we have generated has been made available for them to include in promotional material. It is important for Ireland to have a GMP grade cell manufacturing facility available to the rapidly expanding Irish pharma sector. In the wider EU, the presence of another licensed and trusted GMP facility is also a welcome addition. We hope to work with the CCMI in future as our pre-clinical findings move towards translational to full clinical trials.
Our secondary objective was met in providing compelling evidence that both Fresh and Frozen MSCs isolated and expanded under GMP protocols are efficacious in, to varying degrees, in highly demanding ARDS models. This is vital as there are multiple restrictions on availability of reagents, materials and protocols when cells are to be produced to a GMP standard which are not required with "traditional" general laboratory generated MSCs. We are happy to report that GMP grade MSCs, both Fresh and Frozen broadly recapitulate therapeutic effects in ARDS, reported by our own group and others, that previously utilised general laboratory grade MSCs.
