Table 1 Advantages and limitations of mucus and mucin collection methods
Method | Advantages | Limitations |
|---|---|---|
Cell culture wash | - Requires minimal specialized equipment and is not overly tedious. - Can sample mucus in response to interventions [63, 64]. - Potential for repeated collection and/or longitudinal study. | - Accumulated mucins might not be removed properly if washing is not done successively or is incomplete [65]. - Samples may require pooling [66]. |
Bronchoalveolar lavage | - Allows for direct sampling of the airway fluid - Applicable in vivo [67] and ex vivo [68]. - Relatively large volumes can be retrieved. - Materials to perform are standard. - Can be performed in human patients [69]. - Potential for repeated and/or longitudinal sampling. | - Must be clinically indicated in order to perform in humans. - Generally done under local anesthesia in vivo [70]. - Fluid retrieved is a combination of multiple cells and multiple proteins [67]. - Volume recovered is variable [71]. - Non-adherent proteins may be overrepresented |
Sputum (spontaneous and induced) | - Provides information about mucus and mucins in the lower airways - Spontaneous sputum requires no intervention for its production - Induced sputum provides a higher proportion of viable cells [72]. - Guidelines in place for inducing sputum in human [73]. | - Potential for contaminated with saliva. - Induced sputum usually requires inhalation of hypertonic saline, which can be irritating and change composition of mucus [74, 75]. - Success of sputum induction influenced by inflammation [72]. - Variations in the amount of sputum produced [76]. - Not really applicable to animal models. |
Bronchoscopy | - Direct sampling of mucus when used to remove plugs [77]. - Provides significant diagnostic information. - Can be performed in human and animal patients. | - Performance in human patients or animal patients requires highly specialized equipment and training - Typically performed under conscious sedation, occasionally occur under general anesthesia [70]. |
Endotracheal tube sampling | - Hydration of the mucus varies from the inside or the outside of the tube [80] - Endotracheal tube placement in human and animal patients requires highly specialized training and a licensed medical practitioner. |