Effect of a One Time Dose of Cholecalciferol on Serum Concentration of 25-Hydroxyvitamin D and Macrophages
Effect of a One Time Dose of Cholecalciferol on Serum Concentration of 25-Hydroxyvitamin D and Macrophages
Optimal Vitamin D dosing to obtain adequate serum concentrations of 25-hydroxyvitamin D (25OHD) is controversial. The optimal dose and dosing interval is unknown, and the tendency over the last few years is to give higher, less frequent doses. Disease-specific dosing is of interest, and there may be optimal serum concentration targets based on disease process. The best evidence so far is for optimal bone health, where most experts agree that 25OHD serum concentration should be above 30 ng/ml.
There is mounting evidence that Vitamin D therapy will reduce inflammatory response and macrophage activation. The optimal dosing needed to decrease the inflammatory response is unclear, although our recent mouse model has demonstrated that a onetime high dose is effective. The investigators therefore hypothesize that a one-time high dose of cholecalciferol will be effective in suppression of macrophage production of tumor necrosis factor-alpha (TNFa) and inducible nitric oxide synthase (iNOS). The purpose of this pilot study is to assess the optimum dosage for the most macrophage suppression.
3.4.1 Study Medication (Vitamin D/Placebo): Patients will be blocked randomized into one of four groups using a balanced assignment. The target number of patients is 20, with five patients who have successfully completed all assessments in each group. Groups will be closed to enrollment once their target is reached. The recruitment will continue until every group has reached its target. The investigative pharmacy will prepare each dosage according to the randomization and will hold the key to the dosing.
Participants and investigators will be blinded to those receiving cholecalciferol which comes in 50,000 I.U. dose capsules and those receiving a placebo. Participants will be randomized to 1 of 4 doses as outlined below. All participants will receive the same number of capsules. Five participants will be in each group and will be dosed according to the following dosing schema:
Table 1: Dosing Schema
Cholecalciferol Dosage Group
Control: 0 Cholecalciferol Capsules 4 Placebo Capsules
50,000 I.U.: 1 Cholecalciferol Capsules 3 Placebo Capsules
100,000 I.U.: 2 Cholecalciferol Capsules 2 Placebo Capsules
200,000 I.U.: 4 Cholecalciferol Capsules 0 Placebo Capsules
3.4.2. Skin Thickness Measurement:All testing sites will be evaluated for redness. Skin thickness will also be measured using a micrometer before and after UV exposure.
3.4.3. MED/Sunburn Test: This procedure involves exposing eight 6mm areas of skin over increasing doses of simulated solar radiation (SSR), while the rest of the body is draped. SSR is delivered by a 1,000-Watt xenon arc lamp, which emits ultraviolet wavelengths from 290-400 nm, closely resembling natural sunlight. The minimal erythema dose (MED) will be determined approximately 24 hours after initial exposure by using a chromameter that records the values of redness associated with each exposed 1cm area. The overall differences in MED between the subjects will be assessed.
3.4.4. UVR Exposure: This procedure involves exposing four 6mm areas of skin over increasing doses of simulated solar radiation (SSR), while the rest of the body is draped. SSR is delivered by a 1,000-Watt xenon arc lamp, which emits ultraviolet wavelengths from 290-400 nm, closely resembling natural sunlight. The sites to be exposed will be dosed as follows: 1 MED, 2 MED, 3 MED, 3 MED. Two sites will be exposed for this study, one before study medication dosing and one after study medication dosing.
3.4.5. Blood Draw: samples will be taken by venipuncture to provide samples for analysis of serum 25OHD and macrophages.
3.4.6. Punch Biopsy (Tissue Sample): A punch biopsy is the removal of a small (pencil eraser-sized) circle of skin using a cookie cutter-like instrument. This procedure involves numbing the designated area of skin with lidocaine and the removal of a circle of skin. Prior to obtaining the punch biopsy, the skin will be injected with lidocaine, a painkiller similar to that used by dentists. Although the lidocaine can tingle or hurt briefly during the numbing process, volunteers should not feel any pain while the punch biopsy is being obtained. The circle is then closed using one to five fine stitches per site, which prevents bleeding, speeds healing, and improves the appearance. The stitches are removed 10-14 days later.
3.4.7. Photographs: Photographs of the testing sites will be taken through-out this protocol. In the event that a photograph is taken of the subject's face or any other identifiable feature, the subject's identity may become known.
3.5. STUDY VISITS
3.5.1 Screening Visit
3.5.2 Visit 2: UVR #1
3.5.3 Visit 3: 24hours post UVR #1
3.5.4 Visit 4: 48 hours post UVR #1
3.5.5 Visit 5: 72 hours post UVR #1
3.5.6 Visit 6:1week post UVR #1
3.5.7 Visit 7: UVR #2: 2 weeks post UVR #1
3.5.8 Visit 8: 24 hours post UVR #2
3.5.9 Visit 9: 48 hours post UVR #2
3.5.10 Visit 10: 72 hours post UVR #2
3.5.11 Visit 11: 1 week post UVR #2
3.5.12 Visit 12: 2 weeks post UVR #2
3.5.13 Visit 13: One month post UVR #2
Review of Inclusion and Exclusion Criteria
Review of Adverse Events & Concomitant Medications/Procedures
Photographs of testing sites
4. RISKS AND DISCOMFORTS - MINIMIZED
4.1. Study Medication (Vitamin D/Placebo): Vitamin D is well tolerated and often used in clinical practice. It is freely available as an over the counter supplement. There are few side effects to oral vitamin D, with the most severe being hypercalcemia with prolonged use of a high dose. Vitamin D toxicity can occur when the active form is given (1,25 dihydroxyvitamin D) or with prolonged exposure to high dose vitamin D3. Both young and old adults have taken one time high dose vitamin D3 safely. It is possible that an allergic reaction could occur to the medication and participants will be asked to report and symptoms.
4.2. Skin Thickness Measurement: there are no known risks to evaluating or measuring the skin's thickness with a micrometer.
4.3. Minimal Erythema Dose (MED) and Ultraviolet Light Exposure (UVR): The risks associated with this procedure are minimal, as only the testing sites will be exposed. The consequences of being exposed to UV light are short-term, and primarily involve mild redness at the exposure site followed by minor itching and dryness of the skin several days later. The degree of the sunburn is typically mild to moderate and the UV dose used is not enough to cause blistering of the skin.
4.4. Blood Draw: Risks from a blood draw may include the occurrence of discomfort and/or bruise at the site of puncture and, less likely, the formation of a small clot, swelling of the vein, or bleeding from the puncture site.
4.5. Punch Biopsy (Tissue Sample): Punch biopsies pose minimal risk, and volunteers are instructed as to the proper care of the biopsy site. Lidocaine may cause a tingling or burning sensation when injected into the skin. Potential problems localized to the biopsy site include bleeding or oozing, discomfort, or infection. The biopsy site will heal with a small, flat scar, which may be red for several months. The scar may also turn lighter or darker than the surrounding skin after some time.
4.6. Photographs: There are no known risks to taking photographs. In the event a photograph is taken of the subject's face or any other identifying feature, the patient's identity may be known.
Inclusion Criteria:
Exclusion Criteria: