Low bone density and abnormal bone turnover in patients with atherosclerosis of peripheral vessels.

Patients with vascular calcifications often have low bone mineral density (BMD), but it is still uncertain if osteoporosis and peripheral vascular disease (VD) are interrelated and linked by a common pathomechanism. Moreover, data on bone turnover in patients with advanced atherosclerosis are lacking. We measured BMD by dual-energy X-ray absorptiometry (DXA) and quantitative bone ultrasound (QUS), as well as the serum levels of osteocalcin (OC), bone-specific alkaline phosphatase (BAP), osteoprotegerin (OPG) and its ligand RANKL, and the urinary concentration of the C-terminal telopeptides of type I collagen (CrossLaps), in 36 patient (20 male and 16 female) with serious atherosclerotic involvement of the carotid and/or femoral artery to investigate the underlying mechanism of vascular and osseous disorders. Thirty age-matched and gender matched healthy individuals served as controls. After adjustment for age, BMD was significantly reduced at the lumbar spine in 23/36 (63%) patients (mean T score -1.71+/-1.42) and at the proximal femur in 34/36 (93%) patients (neck mean T score -2.5+/-0.88). Ten patients (27%) had abnormal QUS parameters. Gender and diabetes had no effect on the relationship between vascular calcification and bone density at any site measured. VD subjects had OC and BAP serum levels lower than controls (13.3+/-3.1 vs 27.7+/-3.3 ng/ml, P<0.01, and 8.4+/-2.3 vs 12.5+/-1.4 microg/l, P<0.01, respectively). Urinary CrossLaps excretion was not significantly different in patients with VD and in controls (257.9+/-138.9 vs 272.2+/-79.4 micro g/mmol Cr, respectively). Serum OPG and RANKL levels were similar in patients and in controls (3.5+/-1.07 vs 3.4+/-1.05 pmol/l, and 0.37+/-0.07 vs 0.36+/-0.06 pmol/l, respectively). We proved high occurrence of osteoporosis in VD, with evidence of age and gender independence. Negative bone remodelling balance would be a consequence of reduced bone formation, with no apparent increased activation of the OPG-RANKL system.

Genotypic and phenotypic analysis of Mycoplasma fermentans strains isolated from different host tissues.

A correlation was found between the expression of a specific Mycoplasma fermentans surface antigen (Pra, proteinase-resistant antigen) and the site of isolation of the organism from the infected host. Strains which expressed Pra were most frequently associated with cells of bone marrow origin, and strains which lacked expression of Pra were most commonly isolated from the respiratory tract, genital tract, and arthritic joints, i.e., epithelial cell surfaces. Pra was previously shown to be resistant to degradation by proteinases and was hypothesized to play a protective role at the organism surface and perhaps to influence which host tissue site was colonized by the organism. The methods used for this phenotyping scheme required isolation and growth of the mycoplasma in quantities sufficient for immunoblot analysis using monoclonal antibodies. We wanted to determine a more rapid and less cumbersome technique to supplement this method for determining the Pra phenotype directly in clinical specimens. Here we describe PCR studies to investigate the movement of a previously identified M. fermentans insertion sequence (IS)-like element. These data showed a correlation between a specific IS genotype and the Pra+ phenotype. Production of a 160-bp product using a single set of IS-based primers was associated with expression of Pra. The genomic IS location resulting in the 160-bp product was determined by using Southern blot analysis and was found to be a stable insertion site characteristic of genotype I strains. Additional analyses of sequences within and flanking the IS insertion sites revealed another pair of PCR primer sites which resulted in the consistent production of a 450-bp amplicon. The stability of this site was dependent on the absence of the IS-like element between the primer sites. The production of this 450-bp amplicon correlated with the Pra mutant phenotype and was characteristic of genotype II strains. The data showed that the sequence within the IS may be unstable and that reliable genotyping sequences are more easily found in the stable genomic sites which flank the IS element.