Possible application of Raman microspectroscopy to verify the
interstitial cystitis diagnosis after potassium sensitivity test: Phenylalanine
or tryptophan as a biomarker
Affiliations: Department of Medical Research and Education, Taipei
Veterans General Hospital, Taipei, Taiwan, Republic of China | Department of Obstetrics and Gynecology, Taipei
Veterans General Hospital, National Yang-Ming University and National Defense
Medical Center, Taipei, Taiwan, Republic of China | Department of Obstetrics and Gynecology, Taipei City
Hospital, Taipei, Taiwan, Republic of China
Note: [] Corresponding author: Prof. Shan-Yang Lin, PhD, Department of
Medical Research and Education, Taipei Veterans General Hospital, Taipei,
Taiwan, Republic of China. Fax: +886 2 2873 7200; E-mail: sylin@vghtpe.gov.tw
Abstract: There is lack of a worldwide standard technique for clinical
diagnosis of interstitial cystitis (IC). Raman spectroscopy with higher
specificity and sensitivity has been extensively used to act as a
non-destructive analytical technique without special sample preparation. In
this preliminary study, possible use of Raman microspectroscopy as an IC
diagnostic tool was attempted. Twenty-two participants were screened by
clinical features, history, urodynamic evaluations and potassium sensitivity
test (PST). The freeze-dried water samples voided from all the participants
after PST were directly determined by using a confocal Raman microspectroscopy
to search the biomarker. Participants with or without IC symptom were separated
into control and clinical groups, according to the above screening. The
participants in the clinical group were further divided into mild and severe
subgroups by PST. The symptom of urinary pain and urgency was significant
difference between the mild and severe subgroups (p<0.05). A
significant increase in urinary frequency but a marked reduction in bladder
capacity, maximum cystometric capacity and maximum voiding flow rate were
obtained for clinical group of IC participants, as compared with the result of
control group (p<0.05). By using Raman microspectroscopic
determination, the band near 1003 or 1005 cm^{-1} assigned
to phenylalanine was respectively detected from the freeze-dried water sample
of control group or mild subgroup, but the band at
1010 cm^{-1}due to tryptophan was found in the freeze-dried
water sample of severe subgroup. The result of this preliminary study first
suggests a possible application of Raman microspectroscopy to strongly certify
the results of PST for IC diagnosis. Phenylalanine or tryptophan might be acted
as a biomarker to assist the diagnosis of IC after PST. Particularly, the
appearance of tryptophan might be used to discriminate the severity of IC
symptom.
