Challenges Ahead for a Rational Analysis of Vitamin D in Athletes.

Vitamin D is an essential vitamin for the normal formation of bones and calcium absorption. It is synthesized into our body through sunlight exposure and obtained by consuming foods rich in vitamin D (e.g., fatty fish, eggs yolk, dairy products). Its benefits on the health and performance of athletes are well documented. This article outlines some analytical challenges concerning the analytical quantification of vitamin D for its optimal intake, namely, a comprehensive study of the variability of the assay before categorizing any method as the golden standard, assurance of sample comparability to draw meaningful correlations, revision of the intake guidance based on appropriate statistical power analysis, and the implementation of rational strategies for preventing the underlying mechanism of preanalytical factors. Addressing these challenges will enable the effective management of vitamin D in the sports sector.

Comparative effects of bicalutamide (Casodex) versus orchidectomy on bone mineral density, bone remodelling, and bone biomechanics in healthy rats.

INTRODUCTION: The aim of this work was to analyze the effects produced on bone mineral density (BMD) by the administration of bicalutamide and to compare them with those produced by orchidectomy. Bone formation rate (serum osteocalcin), bone resorption (serum carboxyterminal telopeptide of collagen I; CTX), and biomechanical properties of bone were also studied. METHODS: Thirty-eight male Wistar rats were used: (1) Sham group, rats sham operated at 16 weeks of age; (2) OQX group, rats orchidectomized at 16 weeks of age, and (3) Bic group, rats sham operated at 16 weeks of age and treated during 6 weeks with bicalutamide. The rats were sacrificed at 22 weeks of age, and the BMD in femur and lumbar spine was determined. Serum osteocalcin and serum CTX were also analyzed. Biomechanical parameters related to torsion assay were also studied. RESULTS: The OQX group showed a significant decrease in femoral BMD with respect to Sham rats, whereas bicalutamide treatment did not produce any significant change in BMD. Both Sham and Bic groups showed similar serum osteocalcin and CTX values, whereas OQX rats presented higher osteocalcin and CTX levels than the Sham group. The OQX group showed a significant decrease in femoral thickness. No significant differences were observed in the rest of the biomechanical parameters between groups. CONCLUSION: These results indicate that bicalutamide treatment, in spite of its anti-androgenic properties, does not affect bone remodelling nor BMD in male healthy rats, suggesting that this compound may function as a selective androgen receptor modulator for effects on bone remodelling in the osteoblasts.

Bone remodeling markers in the detection of bone metastases in prostate cancer.

BACKGROUND: Early detection of bone metastases in prostatic carcinoma is very useful in treatment and prognosis of the disease. The aim of this work was to evaluate the sensitivity and specificity of a group of bone markers in order to discriminate between prostate carcinoma patients without (M(0)) and with (M(1)) bone metastases. METHODS: Sixty-seven non-treated patients with: benign prostate hyperplasia (n=21), prostatic carcinoma in several stages without bone metastases (T(X)M(0)) (n=31) and with bone metastases (T(X)M(1)) (n=15) were studied. The following markers were studied: (A) bone formation: (1) serum bone alkaline phosphatase, IRMA (Tandem Ostase, Beckman); (2) serum procollagen I amino-terminal propeptide (PINP), RIA (Orion Diagnostica); (B) bone resorption: (1) urinary collagen I amino-terminal telopeptide (NTX), ELISA (Ostex); (2) collagen I carboxy terminal telopeptide (CTX): (2A) urinary alpha-CTX, RIA (Osteometer), (2B) serum beta-CTX, Elecsys (Roche); (3) collagen I cross-linked carboxy terminal telopeptide (ICTP), RIA (Orion Diagnostica). RESULTS: Levels of all bone markers were significantly higher in group M(1) than in group M(0). A complete separation of groups M(0) and M(1) was achieved with PINP and beta-CTX (100% sensitivity and specificity). CONCLUSIONS: These results support the use of PINP or beta-CTX as a tool to confirm the presence or absence of bone metastases in the first staging of prostatic carcinoma patients.

Human prostatic carcinoma cells produce an increase in the synthesis of interleukin-6 by human osteoblasts.

BACKGROUND: The aim of this work was to evaluate the effect produced by conditioned medium from human prostatic carcinoma cell (PC-3) culture on human osteoblast (HOB) interleukin 6 (IL-6) synthesis. METHODS: PC-3 cells were cultured in Ham's F12K medium with 10% fetal calf serum (FCS) up to confluence. Medium was changed by Dulbecco modified Eagle medium (DMEM)/F12K (1:1) with 0.1% bovine serum albumin. Cells were cultured for 24 hr, and medium (PC-3-CM) was collected. HOBs were cultured up to confluence, and after 48 hr without FCS, medium was removed and PC-3-CM was added to the wells. After 24 hr, supernatant was collected for the determination of IL-6. In another experiment, HOBs were cultured up to confluence in Petri dishes, and after 48 hr without FCS, PC-3-CM or DMEM/F12K (1:1) was added. After different periods of time, medium was removed, and total RNA was extracted. IL-6 mRNA was quantified using reverse transcription polymerase chain reaction. RESULTS: PC-3-CM significantly enhanced IL-6 secretion into HOB culture supernatants (between 1,812% and 372%, depending on the osteoblastic line) with respect to HOBs cultured in DMEM/F12K. PC-3-CM also produced an increase in IL-6 mRNA levels in HOBs. CONCLUSIONS: Prostate carcinoma cells (PC-3) produce a factor or factors that enhance the synthesis and release of IL-6, a known activator of bone resorption.