Circulating immature osteoprogenitor cells and arterial stiffening in postmenopausal osteoporosis.
OBJECTIVE
An increased number of circulating osteoprogenitor cells (OPCs) expressing bone-related proteins and the stem cell marker CD34 have been identified in women with postmenopausal osteoporosis, who also have stiffer arteries than nonosteoporotic subjects. We investigated whether an increased number of circulating OPCs underlies the association of osteoporosis with arterial stiffness.


RESULTS
The number of circulating OPCs was quantified by FACS analysis in 120 postmenopausal women with or without osteoporosis. OPCs were defined as CD34+/alkaline phosphatase(AP)+ or CD34+/osteocalcin(OCN)+ cells. Participants underwent cardiovascular risk factor assessment, measurement of bone mineral density (BMD), and aortic pulse wave velocity (aPWV) as a measure of arterial stiffness. Osteoporotic women had higher aPWV (9.8 ± 2.8 vs 8.5 ± 1.9 m/s, p = 0.005) and levels of CD34+/AP+ and CD34+/OCN+ cells than nonosteoporotic controls [1045 n/mL (487-2300) vs 510 n/mL (202-940), p < 0.001; 2415 n/mL (1225-8090) vs 1395 n/mL (207-2220), p < 0.001]. aPWV was associated with log-CD34+/AP+ (r = 0.27, p = 0.003), log-CD34+/OCN+ cells (r = 0.38, p < 0.001). In stepwise regression analysis CD34+/OCN+ cells, age, systolic blood pressure and heart rate were significant predictors of aPWV (Model R = 0.62, p < 0.001), independent of cardiovascular risk factors, parathyroid hormone levels and osteoporotic status.


CONCLUSIONS
In women with postmenopausal osteoporosis an increased availability of circulating osteoprogenitor cells has a detrimental influence on arterial compliance, which may in part explain the association between osteoporosis and arterial stiffening.
Pirro
M
M
Unit of Internal Medicine, Angiology and Arteriosclerosis Diseases, Department of Clinical and Experimental Medicine, University of Perugia, Hospital Santa Maria della Misericordia, Piazzale Menghini 1, Perugia, Italy. mpirro@unipg.it
Schillaci
G
G
Mannarino
M R
MR
Scarponi
A M
AM
Manfredelli
M R
MR
Callarelli
L
L
Leli
C
C
Fabbriciani
G
G
Helou
R S
RS
Bagaglia
F
F
Mannarino
E
E
D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood / Q000235:genetics; D018952:Antigens, CD34 / Q000097:blood; D001158:Arteries / Q000503:physiopathology*; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure / Q000235:genetics; D015519:Bone Density; D002318:Cardiovascular Diseases / Q000150:complications / Q000503:physiopathology; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008875:Middle Aged; D015675:Osteocalcin / Q000097:blood / Q000235:genetics; D010024:Osteoporosis; D015663:Osteoporosis, Postmenopausal / Q000150:complications / Q000503:physiopathology*; D010045:Outpatients; D018570:Risk Assessment; D012307:Risk Factors; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D014655:Vascular Resistance
D018952:Antigens, CD34; D015415:Biomarkers; D015675:Osteocalcin; D000469:Alkaline Phosphatase