Endocrine Abstracts

Background: The association between primary hyperparathyroidism (PHPT) and cardiovascular disease (CVD) morbidity and mortality is well known in symptomatic PHPT patients. Atherosclerosis is considered nowadays as an inflammatory process. Elevated serum levels of acute phase proteins, C-reactive protein (CRP) and the proinflammatory cytokines tumor necrosis factor alpha (TNF α), Interleukin-6 (IL-6), as well as insulin resistance, indicating chronic subclinical inflammation, have been associated with cardiovascular disease. The aim of this study was to evaluate CVD- related biomarkers of hypercoagulability and inflammation in PHPT patients.

Methods: Thirty-five PHPT patients (aged 57.5±10.8 years) without known CVD were evaluated. Results were compared with those obtained in 25 weight and gender matched controls of similar age. According to disease severity, patients were subdivided into two groups, symptomatic and asymptomatic hyperparathyroidism (SPHP and APHP, respectively).Local Helsinki committee approved the study, and all participants gave their informed written consent. Plasma levels of plasminogen activator inhibitor 1 (PAI-1), fibrinogen, d-dimers, interleukin 6 (IL-6), C-reactive protein (CRP), white blood cells (WBC) were determined in all participants.

Results: PAI-1 was significantly higher in symptomatic PHPT patients (41.4 mg/ml±20) versus APHP and control groups (25.0±12.8 and 32.5 mg/ml±13.0, respectively; P=0.009). Levels of fibrinogen, d-dimers, IL-6, CRP and leukocytes were similar in PHPT and controls. Across all subjects PAI-1 was significantly correlated with PTH levels (r=8.44; P=0.005). After multivariate regression analysis, a significant correlation between Il-6 and PTH was maintained (r=0.43, P=0.008). No significant correlations were found between PTH or calcium levels and values of fibrinogen, d-dimers, CRP, leukocytes.

Conclusions: Our results suggest that PAI-1 as a marker of hypercoagulability is increased in symptomatic PHPT patients. Elevated plasma levels of PAI-1 in PHPT and the significant correlation with PTH levels, suggest that hypercoagulability mechanisms may be operating in the development of CVD in these patients.