Osteoinductive effect of bone bank allografts on human osteoblasts in culture.

Incorporation of a human bone allograft requires osteoclast activity and growth of recipient osteoblasts. The aim of this work was to study the effects produced by autoclavated and -80 degrees C frozen bone allografts on osteoblast proliferation and synthesis of interleukin 6 (IL6), activator of bone resorption, aminoterminal propeptide of procollagen I (PINP), marker of bone matrix formation, and osteoprotegerin (OPG), inhibitor of osteoclast activity and differentiation. Allografts were obtained from human femoral heads. Human osteoblasts were cultured in the presence (problem group) or in the absence (control group) of allografts during 15 days. Allografts produced a decrease in osteoblast proliferation in the first week of the experiment, and an increase in IL6 mRNA, both at 3 h and 2 days, and an increase in the IL6 released to the culture medium the second day of the experiment. We found a decrease in OPG released to the culture on the 2nd and fourth days. These results suggest an increase in bone resorption and a decrease in bone formation in the first week of the experiment. In the second week, allografts produced an increase in osteoblast proliferation and PINP release to the culture medium, indicating an increase in bone formation; an increase in OPG released to the culture medium, which would indicate a decrease in bone resorption; and a decrease in IL6, indicating a decrease in bone resorption stimulation. These results demonstrate that autoclavated and -80 degrees C frozen bone allografts produce in bone environment changes that regulate their own incorporation to the recipient bone.

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.