Associations between osteoporosis and coronary artery disease in postmenopausal women.

OBJECTIVE: Coronary artery disease (CAD) and osteoporosis are major causes of mortality and morbidity in postmenopausal women. We aimed to investigate the association between osteoporosis and CAD in asymptomatic postmenopausal women at a single center. METHODS: This study included 863 postmenopausal women without histories of cardiovascular diseases who visited the Health Promotion Center from June 1, 2004 to May 31, 2015. All subjects were screened for bone mineral density (BMD) by dual-energy X-ray absorptiometry and for the degree of CAD by multidetector computed tomography. RESULTS: Low BMD including osteopenia and osteoporosis was found to be significantly associated with old age, low body mass index, and a higher prevalence of diabetes mellitus. The incidences of CAD including a high coronary artery calcium score (≥100), obstructive coronary artery disease, and multivessel disease were significantly higher in subjects with low BMD. After adjusting for age and cardiovascular risk factors, osteoporosis was associated with a high coronary artery calcium score (p = 0.015) and with obstructive coronary artery disease (p = 0.002). There was a trend toward significance with multivessel disease (p = 0.052). CONCLUSIONS: High coronary artery calcium score and obstructive coronary artery disease, as revealed by multidetector computed tomography, were associated with osteoporosis in asymptomatic postmenopausal women, independent of cardiovascular risk factors and age.

LonR9 carrying a single Glu614 to Lys mutation inhibits the ATP-dependent protease La (Lon) by forming mixed oligomeric complexes.

An unusual lon mutation (called lonR9) is dominant over the wild-type gene, which encodes the ATP-dependent protease La (Lon) in Escherichia coli, when present in multicopy plasmids. Here, we cloned and sequenced lonR9, and showed that the mutant gene carries a single point mutation in its open reading frame, which leads to replacement of Glu614 by Lys. The LonR9 protein and its poly-His-tagged form were purified to apparent homogeneity. Both of the purified proteins were capable of inhibiting the ATP-dependent proteolysis and the protein-activated ATP hydrolysis by protease La. Furthermore, the His-tagged LonR9 protein was found to form mixed oligomeric complexes with protease La, upon analysis by chromatography on a metal-chelating column. These results suggest that the phenotypic dominance of the lonR9 mutant is due to the formation of mixed oligomeric complexes between LonR9 and protease La, in which the defective components prevent the function of the wild-type subunits.