# Application of Conditioned Medium for In Vitro Modeling and Repair of Respiratory Tissue
## 3 Results
### Application of CM from Respiratory Cells or Tissues  
Primary cells or cell lines were one of the most commonly used tissues for secretome collection, and they were involved in 10 of the 26 studies reviewed. In addition to such cells, disease-related tissues such as lymphangioleiomyomatosis (LAM) cells were also  
Figure 1: PRISMA flow diagram. investigated as a disease model [41]. The result metrics used included cell viability assays, proliferation assays, scratch wound migration assays, immunofluorescence, Western blotting, and enzyme-linked immunosorbent assays (ELISA). While most studies examined both proliferation and migration assays, some found that a faster migration rate was often associated with a greater impact of tissue-conditioned media on cell proliferation [37; 42; 43]. Four studies examined cell viability assays [41; 44; 45; 46], where a higher proportion of viable cells was accompanied by a larger estimation of the number of live cells. The 10 studies also conducted specific marker expression experiments, namely immunofluorescence assays, PCR, ELISA, and Western blotting. CK18, KI67, and MUC5B were among the genes expressed [42]. Table 1 summarizes where cell-released factors from respiratory disorder-related tissue, such as LAM-associated fibroblasts and idiopathic pulmonary fibrosis fibroblasts, demonstrated positive effects on respiratory regeneration in vitro, including increased proliferation, migration, and protection against apoptosis. However, cancer-associated fibroblast CM was found to accelerate lung cancer cell metastasis. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**CELL TYPE** & **CM CHARACTER-ISTICS** & **EXPERIMENTAL EVALUATION** & **RESULTS AND CONCLUSIONS** \\ \hline  & & & - & Nodular AT2 expressed protein associated with EC activation, such as matrix MMP7 and FGF7. \\ Lung carcinoma EC (A549), pulmonary alveolar type 2 cells (AT2), tuberous sclerosis complex 2 cells (TSC2), LAM cells [41] & From & Immunohistochemistry, fluorescein diacetate viability assay, immunofluorescence, proliferation assay, yeast carbon migration assay, caspase 3/7 activity assay, ELISA & - & TSC2 + \(\mathrm{LAF}\) derived from LAM exhibited \(\uparrow\) FGF7 compared to LAF alone. \\ Lung carcinoma EC (A549), pulmonary alveolar type 2 cells (AT2), tuberous sclerosis complex 2 cells (TSC2), LAM cells [41] & From & - & LAF-CM + A549 exhibited positively chemotactic feature, \(\uparrow\) rate of repair and migration, and protected against apoptosis. \\ Lung carcinoma EC (A549), pulmonary alveolar type 2 cells (TSC2), LAM-associated fibroblasts (LAF) complex 2 cells (TSC2), cultured for 24 h & & - & LAF-CM accumulation in LAM may alter AT2 cell distribution and proliferation. FGF7 mediated crosstalk between EC and LAF. Thus, this could present new therapeutic options for LAM. \\ \hline  & & & - & LMSC-CM \(\downarrow\) number of necrotic cells on H\({}_{2}\)O\({}_{2}\)-induced cells that caused cellular stress, while also \(\uparrow\) number of viable cells. \\ Primary human lung mesenchymal (A549), human distal lung recommend cells (LMSC) EC (NCI-H441) [44] & From lung-derived mesenchymal stromal cells (LMSC) cultured for 24 h & - & LMSC-CM \(\uparrow\) in multilayer recovery, accelerating wound repair from scratch injury in A549 cells. \\  & & & - & Despite no significant difference between COPD and non-COPD control-derived LMSC, endogenous LMSC were nevertheless identified as a potential target for treatment techniques aimed at correcting aberrant lung tissue repair in COPD.