51. Tear film substance P: A potential biomarker for diabetic peripheral neuropathy
- Author
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Jana Pisarcikova, Ann M. Poynten, Mark D. P. Willcox, Shyam Sunder Tummanapalli, Maria Markoulli, Tushar Issar, Arun V. Krishnan, Aimy Yan, and Natalie Kwai
- Subjects
Adult ,Male ,medicine.medical_specialty ,030209 endocrinology & metabolism ,Substance P ,Type 2 diabetes ,Calcitonin gene-related peptide ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Diabetic Neuropathies ,Ophthalmology ,medicine ,Humans ,Prospective Studies ,Denervation ,Type 1 diabetes ,business.industry ,Nerve plexus ,Middle Aged ,medicine.disease ,eye diseases ,medicine.anatomical_structure ,Peripheral neuropathy ,Cross-Sectional Studies ,chemistry ,Tears ,030221 ophthalmology & optometry ,Female ,sense organs ,business ,Biomarkers - Abstract
To explore the changes that occur in the concentrations of substance P (SP) and calcitonin gene-related peptide (CGRP) in tears as a result of corneal denervation and its association with diabetic peripheral neuropathy (DPN).Sixty-three individuals with type 1 diabetes/type 2 diabetes (T1D/T2D) and 34 age-matched healthy controls underwent a detailed assessment of neuropathy using the Total Neuropathy Score (TNS). The concentration of SP and CGRP in tears was measured by enzyme-linked immunosorbent assay. The corneal sub-basal nerve plexus was imaged using corneal confocal microscopy. Corneal nerve fibre length, fibre density, branch density, total branch density, nerve fractal dimension and inferior whorl length were quantified.In T1D, the median [IQR] concentration of SP in tears was significantly reduced in those with DPN, (130 [61-692]pg/mL) compared to both control subjects (763 [405-1555]pg/mL, P 0.01) and in those without DPN (914 [339-1832]pg/mL, P = 0.01); the concentration of CGRP was not changed. In T2D, there was no difference in neuropeptides between participants with diabetes and controls, regardless of neuropathic status. In T1D and T2D, corneal nerve parameters were significantly different between those with DPN or without DPN and controls. A significant correlation was noted between the concentration of tear film SP and TNS in T1D (r = -0.49; P 0.001) and corneal nerve fibre density (r = 0.45; P 0.001). The concentration of tear film CGRP was correlated significantly with the reduction of corneal nerve fibre density (r = 0.41; P = 0.01) in T1D.Tear film SP may provide a potential non-invasive biomarker for assessing neuropathy in T1D.
- Published
- 2019