title: Concentration of hyaluronic acid in human vocal folds in young and old subjects.
abstract: OBJECTIVE
  To compare and evaluate concentrations of hyaluronic acid (HA) in normal vocal folds of both young and elderly people of both sexes.
  
  
  METHODS
  Experimental study.
  
  
  METHODS
  The research was carried out at the ENT, Head and Neck Surgery Department and the Pharmacology Institute of São Paulo Federal University.
  
  
  METHODS
  Enzyme-linked immunosorbent assay plates coated with biotin-conjugated binding protein and streptavidin-europium conjugate were sequentially incubated with samples from the middle portion of the cover, vocal ligament, and vocal muscle of 19 young and 20 elderly subjects of both sexes. After the release of europium in an enhancement solution, final fluorescence was measured using a fluorometer.
  
  
  RESULTS
  Statistically significant comparisons: (1) all subject groups combined exhibited a higher HA concentration in the cover and ligament compared with the muscle samples; (2) women subjects had a significantly lower HA concentration in muscle compared with the ligament, and male subjects showed significantly lower HA in muscle compared with the cover; and (3) both genders of young subjects showed a higher HA concentration in ligament samples compared with the muscle.
  
  
  CONCLUSIONS
  HA concentrations are higher in the cover and ligament compared with the muscle in both genders and age groups, and there is a higher HA concentration in ligament compared with the muscle of young subjects of both genders. HA levels in the cover samples of younger women showed great variability that may relate to ovarian hormone levels, reflecting different phases of the menstrual cycle.
authors.affiliation: Department of ENT, Federal University of São Paulo, São Paulo, Brazil. gustavokorn@uol.com.br
authors.forename: Gustavo Polacow
authors.initials: GP
authors.lastname: Korn
authors.forename: João Roberto Maciel
authors.initials: JR
authors.lastname: Martins
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Park
authors.forename: Aline
authors.initials: A
authors.lastname: Mendes
authors.forename: Elsa Yoko
authors.initials: EY
authors.lastname: Kobayashi
authors.forename: Helena Bonciani
authors.initials: HB
authors.lastname: Nader
authors.forename: Noemi Grigoletto
authors.initials: NG
authors.lastname: De Biase
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001344:Autopsy; D002352:Carrier Proteins; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D006820:Hyaluronic Acid / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D012494:Sampling Studies; D012737:Sex Factors; D046509:Tissue Culture Techniques; D014827:Vocal Cords / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; C017071:biotin-binding proteins; D006820:Hyaluronic Acid