A novel tetracycline labeling schedule for longitudinal evaluation of the short-term effects of anabolic therapy with a single iliac crest bone biopsy: early actions of teriparatide.
We describe a quadruple tetracycline labeling method that allows longitudinal assessment of short-term changes in bone formation in a single biopsy. We show that 1 month of hPTH(1-34) treatment extends the bone-forming surface, increases mineral apposition rate, and initiates modeling-based formation.


BACKGROUND
Iliac crest biopsy, with histomorphometric evaluation, provides important information about cellular activity in bone. However, to obtain longitudinal information, repeat biopsies must be performed. In this study, we show the capability to obtain short-term longitudinal information on bone formation in a single biopsy using a novel, quadruple labeling technique.


METHODS
Two tetracycline labels were administered using a standard 3 days on, 12 days off, 3 days on format. Four weeks later, the tetracycline labeling was repeated using the same schedule but with a different tetracycline that can be distinguished from the first by its color under fluorescent light. Iliac crest biopsies were performed 1 week later and prepared undecalcified for histomorphometry. Indices of bone formation 1 month apart were measured and calculated using the two sets of labels. We used this method to investigate the early effects of teriparatide [hPTH(1-34)] treatment on bone formation. The results were compared with those from a group of control subjects who were quadruple-labeled, but did not receive hPTH(1-34).


RESULTS
Treatment with hPTH(1-34) dramatically stimulated bone formation on cancellous and endocortical surfaces. This was achieved by both an increase in the linear rate of matrix apposition and extension of the bone-forming surface. New bone was deposited on previously quiescent surfaces (i.e., modeling-based formation), but a proportion of this could occur by encroachment from adjacent resorption cavities.


CONCLUSIONS
A single transiliac crest bone biopsy, after sequential administration of two sets of tetracycline labels is a useful approach to study the short-term effects of anabolic agents on human bone. One month of hPTH(1-34) treatment extends the bone-forming surface, increases mineral apposition rate, and initiates modeling-based formation.
Lindsay
Robert
R
Clinical Research Center, New York State Department of Health, Helen Hayes Hospital, West Haverstraw, New York 10993, USA. lindsayr@helenhayeshosp.org
Cosman
Felicia
F
Zhou
Hua
H
Bostrom
Mathias P
MP
Shen
Victor W
VW
Cruz
JoAnn D
JD
Nieves
Jeri W
JW
Dempster
David W
DW
D045930:Anabolic Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001706:Biopsy / Q000379:methods; D050071:Bone Density Conservation Agents / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007085:Ilium / Q000187:drug effects / Q000473:pathology*; D008137:Longitudinal Studies; D008875:Middle Aged; D010012:Osteogenesis; D015663:Osteoporosis, Postmenopausal / Q000188:drug therapy* / Q000473:pathology; D019379:Teriparatide / Q000494:pharmacology / Q000627:therapeutic use*; D013752:Tetracycline / Q000008:administration & dosage / Q000032:analysis*
D045930:Anabolic Agents; D050071:Bone Density Conservation Agents; D019379:Teriparatide; D013752:Tetracycline