Korean Circ J.  2017 May;47(3):401-408. 10.4070/kcj.2016.0214.

Effect of Rosuvastatin on Bovine Pericardial Aortic Tissue Valve Calcification in a Rat Subdermal Implantation Model

• Lee SH
• Kim DH
• Youn YN
• Lee S
• Joo HC
• Chang BC
• Yoo KJ

• KMID: 2385395
• DOI: http://doi.org/10.4070/kcj.2016.0214

Abstract

BACKGROUND AND OBJECTIVES
There are pathophysiologic similarities between calcification and atherosclerosis because both are the product of an active inflammatory process. The aim of this study was to examine the effects of statin treatment on calcification in bovine pericardial tissue valves.
MATERIALS AND METHODS
Forty Sprague-Dawley rats were randomly divided into 4 groups according to hypercholesterolemia induction and statin intake (Group 1, n=10: normal diet without statin treatment, Group 2, n=10: normal diet with statin treatment, Group 3, n=10: high fat diet without statin treatment, Group 4, n=10: high fat diet with statin treatment). Serum lipid levels were measured just before the experiment and after 4 and 12 weeks. Bovine pericardial tissue valve cusps were surgically implanted in rat dorsal subcutis at 4 weeks. After the surgery, statin was administered daily to Groups 2 and 4. Serum interleukin-6 (IL-6) level was measured at 5 weeks. Cusps were explanted at 12 weeks and calcium levels were determined by atomic absorption spectroscopy.
RESULTS
Mean IL-6 was significantly higher in Group 3 at 5 weeks (7.14, 2.03, 31.70, and 6.90 pg/dL for each group, respectively). Mean calcium level in Group 3 was significantly higher among groups but Group 4 was significantly lower compared to Group 3 and was similar to Group 1, 2 (1.86, 1.92, 2.55, and 1.80 mg/g for each group, respectively, p<0.01).
CONCLUSION
Hypercholesterolemia may be a significant risk factor for bovine pericardial valve calcification. Statin treatment significantly attenuated calcification of bovine pericardial valve tissue in a rat subdermal implantation model and might prolong the durability of bioprostheses.

Keyword

Heart valve; Hypercholesterolemia; Statins (HMG-CoA reductase inhibitor); Aortic valve, calcification

MeSH Terms

Absorption
Animals
Atherosclerosis
Bioprosthesis
Calcium
Diet
Diet, High-Fat
Heart Valves
Hydroxymethylglutaryl-CoA Reductase Inhibitors
Hypercholesterolemia
Interleukin-6
Rats*
Rats, Sprague-Dawley
Risk Factors
Rosuvastatin Calcium*
Spectrum Analysis
Calcium
Interleukin-6
Rosuvastatin Calcium

Figure

• 

  Fig. 1 Valve patch implantation model in rat. (A) Implant preparation. Round shaped implant (small box) was made using skin biopsy punch. (B) Gross appearance after patch implantation.

• 

  Fig. 2 Blood lipid profiles. Blood Tchol level and LDL level were significantly increased in the hypercholesterol diet intake group. In addition, rosuvastatin significantly lowered Tchol and LDL levels in hypercholesterolemic rats. (A) Blood Tchol level just before experiment, (B) blood LDL level just before experiment, (C) blood Tchol level at 4 weeks, (D) blood LDL level at 4 weeks, (E) blood Tchol level at 12 weeks, (F) blood LDL level at 12 weeks. ***p<0.001, ###p<0.001 when compared with other groups, †††p<0.001 when compared with Group 3. NS: not significant, Tchol: total cholesterol, LDL: low density lipoprotein cholesterol.

• 

  Fig. 3 Effect of rosuvastatin on blood Il-6 level and calcium level in the bovine pericardial implant. Rosuvastatin significantly lowered Il-6 level within 1 week after surgery. In addition, rosuvastatin significantly decreased calcium level in hypercholesterolemic animals. (A) Il-6 level at 5 weeks, (B) Il-6 level at 12 weeks, (C) calcium level at 12 weeks. *p<0.05 when compared with other groups, †p<0.05 when compared with group 3. Il-6: interleukin-6.

• 

  Fig. 4 Histopathological analysis. Cellular infiltration was significantly reduced in rosuvastatin-treated groups. (A) Microscopic image of Group 1, (B) microscopic image of Group 2, (C) microscopic image of Group 3, (D) microscopic image of Group 4, (E) graph of nucleated cell count results. (hematoxylin and eosin stain, x200 magnifi cation) *p<0.05 when compared with Group 1, **p<0.01 when compared with Group 1, †††p<0.001 when compared with Group 3.

• 

  Fig. 5 Expression profiles involved in calcification metabolism. (A) Western blot analysis results. OPN and BMP-2 expressions were significantly lower in the rosuvastatin-treated group than in the normal saline-treated group with hypercholesterolemia. (B) Relative density of BMP-2, (C) relative density of OPN. **p<0.01 when compared with other groups, ††p<0.01 when compared with Group 3. †p<0.05 when compared with Group 3. OPN: osteopontin, BMP-2: bone morphogenic protein-2.

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