Experimental Analysis of Tear Fluid and Its Processing for the Diagnosis of Multiple Sclerosis.

A pilot analysis of the tear fluid of patients with multiple sclerosis (MS) collected by glass microcapillary was performed using various experimental methods: liquid chromatography-mass spectrometry, Raman spectroscopy, infrared spectroscopy, and atomic-force microscopy. Infrared spectroscopy found no significant difference between the tear fluid of MS patients and the control spectra; all three significant peaks were located at around the same positions. Raman analysis showed differences between the spectra of the tear fluid of MS patients and the spectra of healthy subjects, which indicated a decrease in tryptophan and phenylalanine content and changes in the relative contributions of the secondary structures of the polypeptide chains of tear proteins. Atomic-force microscopy exhibited a surface fern-shaped dendrite morphology of the tear fluid of patients with MS, with less roughness on both oriented silicon (100) and glass substrates compared to the tear fluid of control subjects. The results of liquid chromatography-mass spectrometry showed downregulation of glycosphingolipid metabolism, sphingolipid metabolism, and lipid metabolism. Proteomic analysis identified upregulated proteins in the tear fluid of patients with MS such as cystatine, phospholipid transfer protein, transcobalamin-1, immunoglobulin lambda variable 1-47, lactoperoxidase, and ferroptosis suppressor protein 1; and downregulated proteins such as haptoglobin, prosaposin, cytoskeletal keratin type I pre-mRNA-processing factor 17, neutrophil gelatinase-associated lipocalin, and phospholipase A2. This study showed that the tear proteome in patients with MS is modified and can reflect inflammation. Tear fluid is not a commonly used biological material in clinico-biochemical laboratories. Experimental proteomics has the potential to become a promising contemporary tool for personalized medicine, and it might be applied in clinical practice by providing a detailed analysis of the tear-fluid proteomic profile of patients with MS.

Associations of optical coherence tomography with disability and brain MRI volumetry in patients with multiple sclerosis.

AIM OF THE STUDY: To investigate in a cross-sectional study the correlations of optical coherence tomography (OCT) with clinical and magnetic resonance imaging (MRI) parameters in multiple sclerosis (MS) patients. MATERIAL AND METHODS: OCT parameters include the peripapillary retinal nerve fibre layer (pRNFL) and ganglion cell complex (GCC). Brain magnetic resonance volumetry (T2- and T1- lesions volume, whole brain volume and grey matter volume) was evaluated using the Icobrain program. Clinical data was compared according to the history of optic neuritis (HON). Correlations were determined between OCT parameters and demographic (age, gender), clinical (disease duration, Expanded Disability Status Scale score [EDSS]), and MRI data. RESULTS: Out of 83 recruited people with MS, 27 had HON. The mean age of 75 patients with non-ON eyes was 42.08 ± 10.36 years, and 70.67% of the sample were females. Significant correlations were found between pRNFL and disability, along with several brain MRI-volumetry variables (Fluid-attenuated Inversion Recovery lesions volume [FLAIR]; T1-hypointense lesions volume; T1-lesions volume change; T1-volume lesions enlarging; whole brain volume; whole brain volume normative percentile; and volume of periventricular lesions). Multivariable linear regression analysis showed that age, pRNFL and GCC were significantly associated with T1-hypointense lesions volume change (the model explained 24% of the overall variance of the dependent variable). CONCLUSIONS: The pRFNL value correlates with disability and brain MRI-volumetric parameters in MS patients, serving as a useful neurodegeneration and inflammation surrogate marker.

Native fluorescence of tear fluid as a tool for diagnostics of glaucoma.

Glaucoma is one of the leading causes of irreversible vision loss worldwide. There is an enormous need for the detection of its early stages and also speeding up and simplifying regular examinations. Among the new diagnostic approaches, the use of tear fluid has been intensively investigated in recent years. For this purpose, we analyzed the tear fluid of patients with glaucoma and related diseases. To sensitively capture the subtle ocular abnormalities related to glaucoma and manifested in tear fluid, we used synchronous fluorescence spectroscopy. In this observational case-control study, we detected significant differences in the intensity of tear fluid fluorescence located at λ ex/Δλ = 280/70 nm between the groups of primary open-angle glaucoma (p < 0.01), suspected glaucoma (p < 0.0001), and ocular hypertension (p < 0.05), when compared to the healthy control group. The signal was not significantly higher in women than in men (p = 0.05), and no correlation was found with age (r = -0.05, p > 0.05), nor treatment (p > 0.05). Taken together, tear fluid fluorescence could serve as a discriminative parameter between patients with glaucoma, related diseases, and healthy control subjects and might contribute to the improvement of diagnostics of these diseases.