Table 4.
The summary of findings regarding 5-HT levels, MAO-B activity, and HTR and MAOB gene variants in asthma.
| Findings | Sample Type/Method | Study |
|---|---|---|
| ↓ 5-HT platelet concentration and ↑ MAO-B platelet activity in asthma patients no association of HTR2A, HTR2C and MAOB polymorphisms with asthma |
human platelets/spectrofluorometry human DNA samples/Real-Time PCR |
this study |
| 5-HT2 activation decreases airway hyperresponsiveness | BALB/c mice (BALF)/PCR, multiplex assays | [38] |
| ↑ HTR2A gene expression in asthma patients vs. control group | human mononuclear cells/Real-Time PCR | [39] |
| ↑ 5HTR2A gene expression in asthma patients vs. control group | human PBMCs/Real-Time PCR | [45] |
| 5-HT2 receptor activation has anti-inflammatory effects | BALB/c mice (BALF)/Real-Time PCR, ELISA | [46] |
| ↑ 5HTR2A gene expression in allergic asthma patients vs. control group no changes in MAO-A expression |
human PBMCs/Real-Time PCR | [44] |
| ↑ 5-HT levels in BALF of asthma patients ↓ 5-HT in the serum of asthma patients |
mouse model and human samples (BALF, cell supernatant, plasma, serum)/enzyme immunoassay | [14] |
| ↑ frequency of HTR4 alleles (+142828G>A and +122769G>A) in asthma patients ↑ frequency of haplotype 1 in block 2 ↓ frequency of haplotype 4 in block 3 |
human DNA samples/Real-Time PCR | [41] |
| ↑ MAO plasma activity and ↓ levels of platelet 5-HT and histamine in asthma patients |
human plasma and platelets | [23] |
| ↑ free 5-HT levels in symptomatic asthma patients vs. asymptomatic patients | human plasma/HPLC-ECD | [13,15] |
| no association between HTR2 variants and bronchial asthma | human DNA samples/MspI restriction polymorphism | [37] |
| altered active 5-HT-transport in asthma patients vs. control group ↑ 5-HT plasma levels |
human plasma (PPP/PRP)/14C- 5-HT uptake | [22,100] |
| ↑ 5-HT during an asthma attack | human blood/fluorometry | [108] |
| ↓ 5-HT uptake in acetylsalicylic acid-induced asthmatic patients vs. control group | human plasma (PPP/PRP)/14C- 5-HT uptake | [21] |
| ↑ 5-HT serum levels in allergic subjects vs. control group | human and guinea pigs serum/spectrofluorometry | [47] |
5-HT = serotonin; HPLC-ECD = high performance liquid chromatography with electrochemical detection; BALF = bronchoalveolar fluid; PPP = platelet poor plasma; PRP = platelet rich plasma; MAO = monoamine oxidase; PCR = polymerase chain reaction; PBMCs = peripheral blood mononuclear cells; ELISA = enzyme-linked immunosorbent assay.