The Role of Cellular Therapy With SVF Cells (Stromal Vascular Fraction) of Adipose Tissue Origin in the Treatment of Pulmonary Fibrosis Post COVD-19

The recent outbreak of Coronavirus 2 (SARS-CoV-2) has spread rapidly throughout the world, resulting in a global pandemic with devastating socioeconomic consequences. After being declared a public health emergency by the World Health Organization (WHO), there is an urgent need to develop effective therapeutic strategies for critically ill COVID-19 patients. This new virus strain causes a complex disease with a wide range of presentations, from mild symptoms to multi-organ failure. A common feature of severe cases is the pathologically complex "cytokine storm" that presents as an excessive immune response with rapid progression of disease and high mortality. In particular, the severe outcomes of SARS CoV-2 are associated with elevated C-reactive protein and Interleukin-6 in the lungs. COVID-19 infection can rapidly decompensate into severe respiratory failure requiring intubation and mechanical ventilation. The need for mechanical ventilation portends a poor prognosis, with a reported mortality rate of up to 88%.

Survivors of COVID-19 pneumonia face sequelae of their disease that affect multiple organ systems. In particular, a significant number present with ongoing problems of breathlessness and reduced oxygenation, turning previously healthy patients into virus-induced pulmonary cripples. The mechanism for this is the intense scarring and destruction of the microcirculation found in the lungs of COVID-19 survivors. There is an urgent need for the development of treatment protocols that are capable of reducing the degree of pulmonary fibrosis and promoting local angiogenesis to better support injured alveoli.

In recent decades, mesenchymal stromal cells (MSCs) have emerged as a potential therapeutic agent for cell-based therapies due to the beneficial effects on immunomodulation and tissue repair/regeneration. These cells possess properties unique self-renewal and capacity to differentiate into multiple lineages. MSCs are found in small numbers in bone marrow (BMSC) and umbilical cord tissue. MSCs are also found in adipose tissue (referred to as ASCs) where they exist as part of a multicellular population, the stromal vascular fraction (SVF). ASC populations are 500-1000 more abundant than their bone marrow counterparts.

Adipose tissue provides a source of Stromal Vascular Fraction (SVF) that can be isolated and transplanted to the patient during the same surgical procedure, at the point of care. SVF is a heterogeneous mixture of stromal progenitor cells, pericytes, endothelial precursor cells, and macrophages. Acting collectively, SVF has been shown to possess broad anti-inflammatory and regenerative properties. SVF has been shown to be safe after IV administration and has shown some promising results in restoring respiratory function in patients with severe lung disorders. Based on public analysis of single cell RNA sequencing (scRNA-seq) data, SVF demonstrates the absence of ACE2 expression, indicating its potential as a resistant phenotype to SARS-CoV-2 infection. In Taken together, IV administration of adipose- derived SVF is presented as a novel treatment approach to improve the clinical outcome of respiratory-compromised COVID-19 patients.

The clinical impact of SVF for COVID-19 is based on 5 mechanisms of action. These have been widely documented (see attached publications and bibliography).