Table 1.

Expression of ACE2 and TMPRSS2 in the SAE of Healthy Nonsmokers before and after Acute Exposure to E-Cigarettes^*

SAE Population	E-cig with Nicotine (FPKM)†	E-cig without Nicotine (FPKM)‡
ACE2§
Preexposure	0.9 ± 0.5	0.7 ± 0.4
Postexposure	0.6 ± 0.2	0.7 ± 0.1
P value‖	>0.1	>0.3
TMPRSS2§
Preexposure	22.5 ± 5.0	22.1 ± 2.2
Postexposure	21.9 ± 4.3	23.4 ± 1.9
P value‖	>0.6	>0.05

Definition of abbreviations: E-cig = e-cigarette; FPKM = fragments per kilobase per million; SAE = small airway epithelium.

^*SAE was assessed in never-smokers (n = 10) before and after acute exposure (2 × 10 puffs, 30 min apart) to “Blu” brand e-cigarettes.

^†A random sample (n = 7) of the nonsmokers was exposed to e-cigarettes with nicotine.

^‡A random sample (n = 3) of the nonsmokers was exposed to e-cigarettes without nicotine.

^§The expression of each of the genes was compared before exposure (baseline) and after exposure (Day 7) within each group of exposure, separately.

^‖P values were calculated using a paired t test.