I looked at the detail of the study... The quality of the results is horrible, the method used to culture the cells, the duration of cell culture, the type of cells they used, the lack of details in the method of extract preparation make me wonder if this paper worth commenting... I read the paper, so lets do it anyway.
The authors... Ms. Wang-Rodriquez position in the list shows that she is not the principal investigator of that study, and probably did not touch a tube in the whole experimentation. 13 authors for such a limited investigation, the first author who's suppose to perform most of the experiments is a graduate student at best, and what a bad first publication as a first author...
Few key details:
- All cells used are cell lines, in other word transformed cells or cancer cells... They are cancer cells before exposure.
- Method: "Because of the high toxicity of cigarette smoke extract, cigarette-treated samples of each cell line could only be treated for 24 h." In some assays cells were treated up to 8-weeks after e-cig extract exposure... What about the control cells?
- "Treatment media was replaced every three days with 1% e-cigarette extract..." For up to 8 weeks? Transformed cells proliferate rapidly in culture, and when the tissue culture flask is overcrowded, cells die spontaneously. During 8 weeks, or even 1 week is madness. Fig 4, the control cells look too healthy for 1 week in culture (I'm very familiar with this assay, from start to finish)... Add to that, the original number of cells seeded, the type of flask used, the number of samples used for statistical analysis are not indicated...
- In many instances, the differences a less than 2-folds...
- Finally, the viability results are inconsistent with previous reports
Obviously, nobody reads these papers no more... No even the reviewers, if this paper has even be reviewed. The only compiling fact in this study is the list of scientific flaws...
Really poor quality research from my stand point... I'm just going to shut-up now.