Calcitonin as an anticalcification treatment for implantable biological tissues

Promising polymeric compounds for coronary stent graft membrane

The literature review discusses the studies on developing the polymer membrane of a coronary stent graft. The new generation of coronary stent grafts is designed to increase the hemocompatibility and ensure its delivery to poorly accessible artery regions. Based on the clinical use results, three groups of promising polymers were identified: biostable polyurethanes, polyvinyl alcohol-based cryogels, bioresorbable compositions based on polylactide-caprolactone and lactic acid-glycolic acid copolymer. However, the possibility of their clinical application requires further experimental studying.

A novel anticalcification treatment strategy for bioprosthetic valves and review of the literature

BACKGROUND AND AIM OF THE STUDY

Glutaraldehyde (Glut) fixed bioprosthetic valves fail due to progressive dystrophic calcification. Many treatments have been proposed to eliminate calcification but none have been entirely successful. Calcitonin (CT) and sodium bisulfite (BSF) have recently been introduced as independent anticalcification reagents. It is postulated that their combined effect, along with the addition of the detergent Tween 80 and alcohol at 37°C, may efficiently minimize tissue calcification due to aldehyde adduct formation and elimination of lipids.

MATERIAL AND METHODS

Three groups were created from porcine aortic leaflets: group I (Glut only), group II (Glut with 1% CT, 12.5% BSF, and 1.2% Tween 80 at 37°C), and group III (Glut with 1% CT, 10% BSF, 1.2% Tween 80, and 20% alcohol at 37°C). All tissues were implanted subdermally in three sets of eight (group I), six (group II), and five (group III) Wistar rats. After 4 months, the tissues were retrieved and lyophilized at -40°C at 100 mm Hg. The calcium was measured with a flat atomic absorption technique.

RESULTS

The preimplantation calcium (Ca) concentration in mg Ca/gram of tissue was 1.79 ± 0.14 in group I, 1.65 ± 0.28 in group II, and 0.72 ± 0.79 in group III (P = ns). After 4 months, the Ca concentration was 277.55 ± 32.52, 103.54 ± 5.39 (P < .001) and 42.02 ± 15.63 (P < .001), respectively. There was also a significant difference (P < .001) between groups II and III.

CONCLUSION

The combination of CT and BSF along with the detergent Tween 80 and alcohol at 37°C mitigates the calcification efficiently as compared to Glut treatment only.