Autologous Lung-Derived Mesenchymal Stem Cell Transplantation in Experimental Emphysema

Abstract

Autologous lung-derived mesenchymal stem cells (LMSCs) were transplanted endoscopically into sheep with experimental emphysema to assess their capacity to regenerate functional tissue. LMSC lines were derived from transbronchial biopsies, cloned at passage 2, expanded in culture, and labeled. A delivery scaffold containing 1% fibrinogen, 20 µg/ml of fibronectin, and 20 µg/ml of poly-L-lysine was used to promote cell attachment and spreading. Treatment animals received scaffold containing 5-10 × 10 6 cells/ site; control animals received scaffold alone. Phenotypic markers, differentiation capacity, extracellular matrix protein expression, and paracrine function of LMSCs were characterized in vitro. Responses to LMSC transplantation in vivo were assessed in terms of clinical toxicity, lung physiology, change in tissue mass (measured by CT scanning) and perfusion (measured by scintigraphy scanning), and tissue histology. At 4-week follow-up, transplants were well tolerated and associated with increased tissue mass and lung perfusion compared to control treatment. Histology confirmed cell retention, increased cellularity, and increased extracellular matrix content following LMSC treatment. Labeled cells were distributed in the alveolar septum and peribronchiolar interstitium. Some label was also present within phagocytes, indicating that a fraction of autologous LMSCs do not survive transplantation. These results suggest that endobronchial delivery of autologous LMSCs has potential therapeutic utility for regenerating functional lung in emphysema.

Lung-Derived Mesenchymal Stromal Cell Post-Transplantation Survival, Persistence, Paracrine Expression, and Repair of Elastase-Injured Lung

“…describe MSCs as highly replicative and clonogenic, as observed here in passaged L-MSCs, and in past studies of outgrowth-derived L-MSCs [31,32]. After 3-4 passages, CFU efficiency reached *20%-25%.…”

“…Differentiation to lung epithelial cells was assessed by incubation of L-MSCs in small airway growth media (SAGM with SingleQuots) containing rhEGF (0.5 ng/mL) for 8 days, and measurement of Aqp5, Ttf-1, proSPC (Sftpc), and CCSP (Scgb1A1) mRNA expression. qPCR was performed according to past descriptions from our laboratory [32,37] using housekeeping genes (average of Hrtp1, GusB, and GADPH) for normalization of mRNA. Details of qPCR methodology are provided in the Supplementary Methods.…”

“…For instance, BM or adipose-derived MSCs significantly reduced injuries caused by elastase [4][5][6][7], lipopolysaccharide [8,9], sepsis [10,11], hyperoxia [12][13][14][15][16][17], and bleomycin [18][19][20][21][22]. In general, the reparative effects of MSCs were compared with control treatments such as irradiated BMMSCs, lung fibroblasts, dermal fibroblasts, or embryonic fibroblast cell lines, rather than MSCs of lung origin, which have only recently been described in mice [23][24][25][26][27], humans [28][29][30], and sheep [31,32]. Whether lung-derived MSCs (L-MSCs) are close or distant relatives of BM-MSCs with respect to in vivo identity, cellular physiology, and therapeutic potential is unclear as is the significance of their stemness in vitro [33].…”

“…In another study in mice, L-MSCs (called multipotent lung stem cells) isolated by direct sorting (Sca-1 pos , CD31 neg , CD45 neg ) were shown to protect against elastase injury through paracrine signals [25]. Two recent studies from our laboratory employing autologous L-MSCs in an ovine model of emphysema [32,35] demonstrate significant improvements in tissue mass, perfusion, and diffusion capacity when cell were delivered intrabronchially within a biological scaffold designed to improve adherence and retention of transplanted cells. These studies show that L-MSCs, like MSCs derived from outside the lung, deliver paracrine signals that are relevant to alveolar homeostasis and injury repair, but the effectiveness of L-MSCs in comparison to BM-MSCs is unknown.…”

Best of Milan 2017—repair of the emphysematous lung: mesenchymal stromal cell and matrix

“…As an example, BM derived-MSCs are able to inhibit the release of pro-inflammatory cytokines and stimulate the functional activity of regulatory T-lymphocytes (10,11). On the other hand, lung derived-MSCs express several basement membrane proteins and growth factors which seem to amplify their retention in the injured tissue (12). In COPD, inflammatory tissue damage is extensive, and inflammation persists even after smoking cessation (13).…”