The eyes can also activate vitamin D – Feb 2014

Characterization of Vitamin D Production by Human Ocular Barrier Cells

Invest. Ophthalmol. Vis. Sci. February 27, 2014 IOVS-13-13019
Jawaher A Al Salem 1, Deepali Patel 1, Radhika Susarla 2, Miguel Coca-Prados 3, Rosemary Bland 4, Elizabeth A Walker 5, Saaeha Rauz 6 and Graham R. Wallace 7,*
1Academic Unit of Ophthalmology, University of Birmingham, College of Medical and Dental Sciences, Edgbaston, Birmingham, B15 2WD, United Kingdom
2University of Birmingham, Birmingham, B15 2WD, United Kingdom
3Department of Ophthalmology and Visual Science, Yale University, PO Box 208061, New Haven, Connecticut, 06520 8061, United States
4University of Warwick, Coventry, CV4 7AL, United Kingdom
5Clinical and Experimental Medicine, University of Birmingham, College of Medical and Dental Sciences, Edgbaston, Birmingham, B15 2WD, United Kingdom
6Academic Unit of Ophthalmology, School of Immunity and Infection, University of Birmingham, College of Medical and Dental Sciences, Birmingham and Midland Eye Centre, Dudley Road, Birmingham, B18 7QU, United Kingdom
7Academic Unit of Ophthalmology, University of Birmingham, College of Medical and Dental Sciences, Edgbaston, Birmingham, B15 2TT, United Kingdom
* Academic Unit of Ophthalmology, University of Birmingham, College of Medical and Dental Sciences, Edgbaston, Birmingham, B15 2TT, United Kingdom g.r.wallace at bham.ac.uk

Purpose:Vitamin D3 is a secosteroid mainly synthesized from the conversion of the skin precursor 7-dehydrocholesterol to vitamin D3 by ultraviolet (UV) B sunlight. Extra-renal synthesis of vitamin D3 has been reported in many tissues and cells including barrier sites. This study characterizes the expression of components of vitamin D signaling in human ocular barrier cells.

Methods:Human conjunctival epithelial (CCL20.2), human corneal endothelial (HCEC-12), non-pigmented ciliary body epithelial (ODM-2), and adult retinal pigment epithelial (ARPE-19) cell lines and primary human scleral fibroblasts (HSF), were analyzed for the expression of vitamin D receptor (VDR), the vitamin D activating enzymes 1α-hydroxylase (CYP27B1), 25-hydroxylases (CYP27A1 and CYP2R1), the vitamin D inactivating enzyme 24-hydroxylase (CYP24A1), and endocytic receptors cubulin and megalin utilizing a combination of RT-PCR, Immunocytochemistry and EIA.

Results:CCL20.2, HSF, HCEC-12, ODM-2, and ARPE-19 express mRNA and protein for all vitamin D synthesizing and metabolizing components. The cell types tested except HSF are able to convert inactive 25-hydroxyvitamin D3 (25(OH)D3) into active 1,25-hydroxyviatmin D3 (1,25(OH)2D3) in the order of HCEC-12>ODM2>CCL20.2>ARPE >HSF.

Conclusions: This novel study demonstrates that ocular barrier epithelial cells express the machinery for vitamin D3 and can produce 1,25(OH)2D3. We suggest that vitamin D3 might play a role in immune regulation and barrier function in ocular barrier cells.

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See also Vitamin D Life

• Vitamin D3 becomes Calcidiol which becomes Calcitriol
• PhD Dissertation - Local production of active vitamin D inhibits Prostate Cancer – Oct 2012
• Kidney not essential for Vitamin D3 activation – fungi can do it – Jan 2014
• Bones can activate vitamin D – July 2013
• Perhaps even mitochondria can activate vitamin D – April 2013
• The lungs can activate vitamin D locally – a Vitamin D inhaler may help lungs – Aug 2016
• Overview Kidney and vitamin D contains the following summary
• FACT: Kidney is the primary way to activate vitamin D
• FACT: When the Kidney has problems, there is less active vitamin D (Calcitriol) for the body
• FACT: When the Kidney has problems, there is increased death due to many factors - many of which are associated with lack of Calcitriol
• FACT: There are many on-going intervention clinical trials trying to determine how much of what kind of vitamin D is needed to treat the problem
• FACT: One Randomized Controlled Trial has proven that Vitamin D treats CKD
• FACT: Taking extra Vitamin D, in various forms, does not cause health problems - even if poor kidney
• Suggestion: Increase vitamin D getting into body now - and increase co-factors so that the vitamin D can be better used
    Sun, UV lamp, Vitamin D supplement - probably > 5,000 IU,
  Calcitriol - which bypasses the need for the kidney to activate vitamin D
    Problems with Calcitriol however: typically only lasts for a few hours, also, possible complications
      Update: Pre-cursor of active vitamin D made from plants is better than calcitriol – Sept 2012
• Category Kidney and Vitamin D contains 193 items