Soluble endoglin as a perspective marker of endothelial dysfunction in patients with primary hyperparathyroidism: a pilot study

BACKGROUND: Primary hyperparathyroidism  (PHPT), one of the most common endocrine pathologies, is associated with a higher incidence of cardiovascular diseases, in particular, those caused by endothelial dysfunction. Evaluation of endothelial dysfunction in patients with PHPT will predict the development of cardiovascular pathology and determine the optimal tactics for PHPT management.AIM: To evaluate the concentration  of soluble endoglin  and photoplethysmographic parameters as potential markers of endothelial dysfunction in patients with PHPT.MATERIALS AND METHODS:  A single-center interventional single-stage study was carried out. 2 groups were formed. The first group included 50 patients with verified PHPT who did not have cardiovascular or other concomitant somatic pathologies in anamnesis. The comparison group included 21 healthy volunteers comparable in sex and age. All participants underwent a biochemical blood test (total calcium, ionized, albumin, lipidogram, urea, uricacid, glucose, creatinine, alkaline phosphatase), parathyroid hormone, 25 (OH) D and endoglin concentrations were evaluated. In addition, echocardiography, ultrasound of the brachiocephalic arteries and arteries of the lower extremities, as well as photoplethysmography were performed.RESULTS: The groups differed in mineral parameters associated with PHPT; no differences were found in parameters of lipid, uric acid and carbohydrate metabolism. Serum levels of endoglin  were lower in PHPT patients (p=0.002). We found a negative correlation between the concentration of albumin-corrected calcium and PTH with endoglin (r1=-0.370, p1=0.003 and r2=-0.475, p2<0.001, respectively) and a positive correlation between the concentration of endoglin  and phosphorus (r=0.363, p=0.003). These associations s were accompanied by changes in photoplethysmographic parameters that indicate an increase in the vascular wall stiffness.CONCLUSION: The serum level of soluble endoglin  is lower in patients with PHPT than in healthy volunteers, negatively correlates with calcium and PTH concentrations and positively with serum phosphorus concentrations. Further studies will make it possible to establish the pathogenetic mechanism of the identified relationships and evaluate the role of endoglin as a potential predictor of cardiovascular pathology in PHPT population.