There is a medical condition involving the backflow or retrograde flow of the contents of the stomach to the larynx and pharynx to contact the upper aero-digestive tract. This condition is called Laryngopharyngeal reflux (LPR). Research by El-Serag in Clinical Gastroenterology and Hepatology showed that the occurrence of such acid reflux conditions has shot up by 4% since 1976. Another article in Laryngoscope showed that the time period between 1990 and 2001 saw an increase of 500% in consulting a doctor for LPR!
According to Campagnolo and team in the International Archives of otorhinolaryngology (2014), the symptoms of LPR are on the lines of other conditions such as smoking, heavy drinking, infection and even excessive vocal abuse making the diagnosis challenging. In case the diagnosis is not prompt, patients experience suffering. The symptoms range from hoarseness to lots of throat clearing and a feeling that there is a lump in the throat. The involvement of LPR has been suggested by research in several diseases such as reflux laryngitis, ulcers, and laryngeal carcinoma.
While there have been reports looking at biomarkers of this condition, a precise test for diagnosing this condition is yet to see the light of the day. This becomes more important given that 10% of people visiting an otolaryngology clinic face LPR-associated issues, according to Johnston and team in The Annals of the New York Academy of Sciences.
Interesting aspects have emerged from research as to how several areas of the larynx show resistance to LPR. Each zone expresses different susceptibility to the disease by varying the expression of genes. Thus, appropriate in vitro models are required to study this damaging condition to understand the condition better so that the diagnosis can be improved.
As primary cultures allow for developing models specific to sites, a team led by Mo reported the primary culture of epithelial cells in Cell Transplantation from laryngeal surgery patient biopsies. Following finely chopping the samples, Dispase II was added followed by Trypsin/EDTA. The cells were seeded on serum-free keratinocyte media KGM for culture. The cells isolated were positive for expected markers such as cytokeratin and Ki-67.
Different areas of the larynx have been shown to express genes differentially; for example, 2016-published research in The Yonsei Medical Journal showed that certain areas show higher levels of CAIII and Hsp70. The established primary culture too was found to express the marker cytokeratin differently with the highest expression in the postcricoid zone.
A major factor that influenced the culture was the age of the sample donor; increased age showed lower cell vitality. Thus, epithelial cells of the larynx can be cultured to show similar features seen in vivo that can allow studies to understand the mechanism of LPR and help address this “pain in the throat”.
El-Serag H B. Time trends of gastroesophageal reflux disease: a systematic review. Clinical Gastroenterology and Hepatology. 2007; 5:17–26.
Altman K W, Stephens R M, Lyttle C S, Weiss K B. Changing impact of gastroesophageal reflux in medical and otolaryngology practice. Laryngoscope. 2005;115:1145–1153.
Campagnolo, AM, Priston J, Thoen R H et al. Laryngopharyngeal reflux: diagnosis, treatment, and latest research. International archives of otorhinolaryngology. 2014. 18(2), 184–191.
Johnston N, Ondrey F, Rosen R, Hurley BP, Gould J, Allen, J DelGaudio, J Altman, KW. Airway reflux. The Annals of the New York Academy of Sciences. 2016;1381(1):5–13.
Mo TT, Tan JJ, Wang MG, et al. Optimized Generation of Primary Human Epithelial Cells from Larynx and Hypopharynx: A Site-Specific Epithelial Model for Reflux Research. Cell Transplantation 2019: 630–637.
Min HJ, Hong SC, Yang HS, Mun SK, Lee SY. Expression of CAIII and Hsp70 Is increased the mucous membrane of the posterior commissure in laryngopharyngeal reflux disease. The Yonsei Medical Journal. 2016;57(2):469–474.