Clinical relevance of heparin-PF4 complex antibody in DVT after total joint replacement

<p>Abstract</p> <p>Background</p> <p>Antibodies to the heparin-platelet factor-4 (HPF-4) complex (HIT antibodies) have been observed in patients with heparin-induced thrombocytopenia (HIT). These antibodies are thought to be involved in thrombosis through activation of platelet/endothelial cells. This prospective study was conducted to determine the incidence of post-operative HIT antibodies to assess the associated risk of deep vein thrombosis (DVT) in patients undergoing total knee arthroplasty (TKA) or total hip arthroplasty (THA).</p> <p>Methods</p> <p>We studied 104 patients who underwent unilateral primary TKA (n = 44) and primary THA (n = 60) with short-duration prophylaxis (1–2 days of a fixed dose of unfractionated heparin). HIT antibodies were assayed using a sandwich-type ELISA before the operation and after heparin treatment (post-operative day 7).</p> <p>Results</p> <p>In the clinical outcome, the incidence of symptomatic DVT was 15.4% (16/104, TKA; 10, THA 6) and pulmonary embolism (PE) was not observed. The total seroconversion rate of HIT antibodies at post-operative day 7 was 34.6% (36/104). Among 36 seroconverted patients, 11 (30.6%) developed symptomatic DVT and 5 out of 68 of the non-seroconverted patients (7.4%) developed symptomatic DVT. The incidence for DVT was significantly higher in the seroconverted patients compared with that of the non-seroconverted patients (odds ratio 5.5, 95%CI: 1.7–17.6 <it>p </it>= 0.0028). Furthermore, in the patients with symptomatic DVT, the titer of HIT antibodies at post-operative day 7 was significantly higher compared with those without symptomatic DVT.</p> <p>Conclusion</p> <p>Our data therefore suggest that seroconversion for HIT antibodies generated by heparin is associated with a risk of DVT in patients undergoing total joint replacement.</p

Effect of high glucose levels on the calcification of vascular smooth muscle cells by inducing osteoblastic differentiation and intracellular calcium deposition via BMP-2/Cbfα-1 pathway

In this paper, we investigate the effect and the possible mechanism of high glucose levels on the calcification of human aortic smooth muscle cells (HASMCs). HASMCs were divided into four groups: normal glucose group (NG), osmolality control group (OC), high glucose group (HG, HASMCs culture medium containing 30 mmol/L glucose), and high glucose plus recombinant human Noggin protein (bone morphogenetic protein-2 (BMP-2) antagonist) group (HN). The mRNA levels and the protein expressions of BMP-2 and core binding factor alpha-1 (Cbfα-1) were measured by real-time quantitative polymerase chain reaction (PCR) and Western blot. After induced by 10 mmol/L β-glycerol phosphoric acid, cells were harvested for assessments of alkaline phosphatase (ALP) activities at Days 1, 2, and 3, and intracellular calcium contents at Days 7 and 14, respectively. High glucose levels increased the mRNA levels and the protein expressions of BMP-2 and Cbfα-1 (P<0.05). The expression of Cbfα-1 was partially blocked by Noggin protein (P<0.05), while BMP-2 was not (P>0.05). After being induced by β-glycerol phosphoric acid, high glucose levels increased the ALP activity [(48.63±1.03) vs. (41.42±2.28) U/mg protein, Day 3; P<0.05] and the intracellular calcium content [(2.76±0.09) vs. (1.75±0.07) μmol/mg protein, Day 14; P<0.05] in a time-dependent manner when compared with the NG group, while the ALP activity could not be blocked by Noggin protein [(48.63±1.03) vs. (47.37±0.97) U/mg protein, Day 3; P>0.05]. These results show that high glucose levels can evoke the calcification of HASMCs by inducing osteoblastic trans-differentiation and intracellular calcium deposition via the BMP-2/Cbfα-1 pathway, which can be partially blocked by Noggin protein