Abstract
Purpose :
The metabolic importance of vitamin D3 has been increasingly observed, and its deficiency is related to several diseases, including eye diseases (glaucoma, AMD, keratoconus, uveitis) and neurodegenerative diseases (Parkinson, Alzheimer, multiple sclerosis, dementia). Its level is almost always measured only in plasma, and little importance has been due to tear and salivary levels. The aim of this study is to simultaneously assess, for the first time in the medical literature, the levels of vitamin D3 in plasma, saliva and tears in healthy subjects.
Methods :
Blood, saliva and tear samples were collected from 12 healthy individuals, with blood collected by venipuncture, saliva was collected in appropriate tubes and tears were collected by Schirmer stripes. The method used to detect vitamin D3 in all these fluids was electrochemiluminescence and the exams were evaluated at the Clinical Analysis Department, Faculdade de Medicina do ABC, Brazil .
Results :
Plasma, tear and salivary levels of vitamin D3 were evaluated in 12 healthy individuals, between 29 and 61 years old, mean of 45,33 years , 6 men and 6 women, and the mean results found were: 90.71 ng/ml ( sd +/- 11,62 ) in the tear, 86,46ng/ml ( sd +/- 13,95) in saliva and 25,77 ng/ml ( sd +/- 9,17) in plasma. No statistically significant difference was found between tear and salivary vitamin d3 values ( p <0,05), but a statistically significant difference was found between tear and plasma vitamin D3 levels (p<0.00001) and between salivary and plasma vitamin D3 levels (p<0.00001), indicating that in these fluids the levels of vitamin D are much higher than in plasma.
Conclusions :
The results show that vitamin D3 levels were statistically similar in saliva and tears, but the results from each of these fluids were much higher than in plasma.These results make us reflect on the possibility that in saliva and tears, fluids in contact with body tissues, levels of vitamin D3 may be higher due to the tissue need for this vitamin, which may suggest that it is the free and effective fraction of vitamin D3, while it is transported in the blood, with the aim of reaching the tissues and then carrying out its functions. If so, and more studies will be needed to explain these results and confirme this possibility, we will have to reevaluate in which liquid we should dose vitamin D3 most appropriately, in physiological and clinical terms.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.