Analyzing Tear Fluid Composition by Synchronous Fluorescence for Diagnosing Dry Eye Disease and the Role of Phytotherapy Intervention.

PURPOSE: Tear fluid gained attention as a representative biological fluid. Its simple and non-invasive collection methods as well as richness of candidate biomarkers made it a potential diagnostic tool for different diseases such as dry eye. Synchronous fluorescence spectroscopy is a highly sensitive analytical tool that results in narrowing and enhanced peak resolution, and has a potential role in disease diagnosis, biomarker identification, and therapeutic monitoring. We applied synchronous fluorescence spectroscopy to monitor variations of tear fluid composition during the development of dry eye disease and to evaluate the potential effects of phytotherapy. METHODS: Dry eye model was induced in Chinchilla rabbits by instillation of 1% atropine sulfate ophthalmic solution. Then, the tear fluid was collected at 3, 7, and 14 days and subjected to synchronous fluorescence spectroscopy. Phytotherapy was achieved by topical instillation of 20 µl of water extracts of pomegranate peel or green tea powders. RESULTS: The fluorescence results revealed changes in the structure of tear fluid over time and the eye is subjected to toxification due to oxidative stress. In addition, dry eye disease was found to affect the metabolic/energetic state of the eye. On the other hand, phytotherapy led to enhancement of the metabolic/biosynthesis state due to activation of flavin adenine dinucleotide-associated proteins. CONCLUSION: There was change in the electrical conductivity of tear fluid proteins. In the case of dry eyes, they became electrical insulators, while in the case of treatment with extracts, their electrical conductivity properties improved. The effects of phytotherapy can be related to the high content of ellagic acid and anthocyanin of pomegranate extract, while in green tea, they are related to catechins and phenolic compounds.

The impact of photoreceptor layer loss on different ocular tissues: Insights from FTIR spectroscopy.

Photoreceptor loss has significant consequences for visual function, and its management is a critical component for treating not only retinal diseases such as age-related macular degeneration and retinitis pigmentosa but also its ocular consequences. On the other hand, Fourier transform infrared spectroscopy is an excellent tool to investigate molecular structure and dynamics of biological samples, and as a non-destructive and label free measurement, it does not perturb the samples. In this study, detailed analyses of the recorded FTIR spectra from cornea, lens and sclera were performed to monitor the distribution of ocular abnormalities due to photoreceptor layer loss after 1, 3 and 6 days. FTIR data were statistically evaluated by multivariate analysis and Bonferroni means comparison. The obtained results revealed that ocular abnormalities associated with photoreceptor layer loss are varied among the investigated tissues, and comprise changes in both hydrogen bond network around proteins and lipid disorder. Structural modifications of protein secondary structure were reported in all investigated tissues. Clinically, the concluded information from FTIR data and its statistical evaluation can contribute to the development of therapeutic strategies for these heterogeneous changes.

Potential role of blood constituents in pain-relief associated with fibromyalgia treatment with extremely low magnetic field: Spectroscopic investigation.

Magnetic field is used as an adjunct therapy for pain control and relief of musculoskeletal pain conditions as Fibromyalgia. It is regarded as more natural and less harmful alternative to analgesic compounds. The exact mechanism underlying these positive effects is still to be determined. Twenty-three patients diagnosed with Fibromyalgia condition were included in this study, and subjected to extremely low magnetic field treatment sessions. The treatment protocol based on exposing patients to gradually increased magnetic field strength that starts with 0.1 µT at the beginning, and increased gradually to 100 µT (3.33 µT/min). UV-Visible, mid-IR and fluorescence characteristics of whole blood, erythrocytes and hemoglobin were investigated; in addition to RBCs-osmotic fragility measurements. The obtained results were analyzed according to control-sham exposed patients. We observed marked changes in the blood (and/or its constituents) absorption spectra of fibromyalgia patients that indicate an enhancement in the energetic pathways and increased hemoglobin-oxygen affinity; in addition, the osmotic fragility measurements show that erythrocytes were characterized by increased elasticity and rehydration. The analyses of infrared spectra show that magnetic field treatment was associated with changes in the erythrocytes skeleton where α-helix component of protein secondary structure is dominant. This study provides scientific evidence that pain relief associated with extremely low magnetic field treatment can be directly related to its systemic effects as well as the enhancement of the cellular activities.

Spectroscopic investigation of retinal degeneration unravel molecular changes associated with vision impairment.

Although retinal degeneration is one of the causes of blindness worldwide and involve the loss of the photoreceptors of the retina, the cause(s) of its development still need to be determined in order to reach an effective treatment instead of trying to slow the progression of the disease. Retinal degeneration condition was induced by intravitreal injection of 2 µl of adenosine triphosphate (ATP) solution. The progress of the disease was monitored by retinal imaging (ocular coherence tomography, OCT) after 1, 8 and 15 days of injecting ATP. At the end of each period, retinal tissue was obtained where retinal proteins were extracted and then subjected to spectroscopic studies. Another part of the retinal tissue was investigated by Fourier transform infrared spectroscopy. The OCT images reflect significant reduction in retinal full thickness and provide evidence of intraretinal inflammation while; the obtained results indicate that both primarily and secondary structure of retinal proteins are influenced by the degeneration condition and, the electrical conductance of retinal proteins is decreased due to degeneration condition. Multivariate principal component analysis identifies that the variance noticed in the infrared spectra due to degeneration condition is not time dependent and revealed intra-groups structural dissimilarity. This dissimilarity was clearly resolved by fluorescence study where the content of amino acids phenylalanine, tryptophan and tyrosine varies with the progress of the degeneration condition. All together provide scientific facts that vision impairment is due to loss of signal transduction and formation of protein aggregates as well.

FTIR assessment of the effect of Ginkgo biloba leave extract (EGb 761) on mammalian retina.

Ginkgo biloba extract has been therapeutically used for several decades to increase peripheral and cerebral blood flow as well as for the treatment of dementia. The extract contains multiple compounds such as flavonoids and terpenoids that are thought to contribute to its neuroprotective and vasotropic effects. In this study, we investigated the effect of prolonged administration of EGb 761, up to 10 weeks, on mammalian retina using Fourier transform infrared spectroscopy (FTIR). Two main groups were involved in this study: the normal group (n = 10); and EGb-administrated group (n = 50) that received-orally-a dose of 40 mg/kg/day EGb 761. The results demonstrated that EGb administration was associated with different beneficial effects on the retinal constituents especially the underlying amide I protein secondary structure components as well as the NH-OH region. It concluded that the optimum daily administration period of EGb (40 mg/kg) for ophthalmic applications that targeting the retina ranges from 5 to 8 weeks.