Serum prolidase activity and left ventricular diastolic dysfunction: the contribution of the autonomic nervous system function

To the Editor With great interest, we read the recent article by Erkus et al.1 regarding the association between the serum prolidase activity and left ventricular diastolic dysfunction (LVDD). The authors very clearly discussed the relation of the serum prolidase level – which is an important factor in collagen metabolism, matrix remodelling and cell growth – and LVDD. In addition to their discussion, we aimed to emphasize the possible other relative mechanism between the prolidase and left ventricular diastolic dysfunction: the effect of the autonomic nervous system function. In the literature a lot of studies showed the associations between alterations in the autonomic nervous system and the development of left ventricular diastolic dysfunction2-4. Poireir et al. showed a relation between left ventricular diastolic dysfunction and cardiac autonomic dysfunction. Habek et al. also found a close correlation between left ventricular diastolic function with heart rate and its variability in diabetes mellitus type 2 patients4 . Prolidase is an enzyme that catalyzes the final step of collagen breakdown, a step-limiting factor in the regulation of collagen biosynthesis5. Also, prolidase plays a role in collagen metabolism, matrix remodelling and cell growth. Previously, impaired autonomic functions have been clearly shown to have an important relationship with collagen metabolism and remodelling6-8.As a consequence, we believe that the impairment on cardiac autonomic nervous system function may play a role in the result of the article by Erkus et al.1. We hope that the above-mentioned items would add to the value of the well-written article of Erkus et al. regarding the relation between serum prolidase activity and left ventricular diastolic dysfunction.