natriuretic-peptide--c-type and Hyperplasia

As a result of thrombosis or intimal hyperplasia, synthetic artificial vascular grafts had a low success rate when they were used to replace small-diameter arteries (inner diameter < 6 mm). C-type natriuretic peptides (CNP) have anti-thrombotic effects, and can promote endothelial cell (EC) proliferation and inhibit vascular smooth muscle cell (SMC) over-growth. In this study, poly(ε-caprolactone) (PCL) vascular grafts loaded with CNP (PCL-CNP) were constructed by electrospinning. The PCL-CNP grafts were able to continuously release CNP at least 25 days in vitro. The results of scanning electron microscopy (SEM) and mechanical testing showed that the loading of CNP did not change the microstructure and mechanical properties of the PCL grafts. In vitro blood compatibility analysis displayed that PCL-CNP grafts could inhibit thrombin activity and reduce platelet adhesion and activation. In vitro cell experiments demonstrated that PCL-CNP grafts activated ERK1/2 and Akt signaling in human umbilical vein endothelial cells (HUVECs), as well as increased cyclin D1 expression, enhanced proliferation and migration, and increased vascular endothelial growth factor (VEGF) secretion and nitric oxide (NO) production. The rabbit arteriovenous (AV)-shunt ex vitro indicated that CNP loading significantly improved the antithrombogenicity of PCL grafts. The assessment of vascular grafts in rat abdominal aorta implantation model displayed that PCL-CNP grafts promoted the regeneration of ECs and contractile SMCs, modulated macrophage polarization toward M2 phenotype, and enhanced extracellular matrix remodeling. These findings confirmed for the first time that loading CNP is an effective approach to improve the hemocompatibility and vascular regeneration of synthetic vascular grafts. STATEMENT OF SIGNIFICANCE: Small-diameter (< 6 mm) vascular grafts (SDVGs) have not been made clinically available due to their prevalence of thrombosis, limited endothelial regeneration and intimal hyperplasia. The incorporation of bioactive molecules into SDVGs serves as an effective solution to improve hemocompatibility and endothelialization. In this study, for the first time, we loaded C-type natriuretic peptides (CNP) into PCL grafts by electrospunning and confirmed the effectiveness of loading CNP on improving the hemocompatibility and vascular regeneration of artificial vascular grafts. Regenerative advantages included enhancement of endothelialization, modulation of macrophage po

Topics: Animals; Biocompatible Materials; Blood Vessel Prosthesis; Caproates; Cyclin D1; Human Umbilical Vein Endothelial Cells; Humans; Hyperplasia; Lactones; Natriuretic Peptide, C-Type; Nitric Oxide; Polyesters; Proto-Oncogene Proteins c-akt; Rabbits; Rats; Regeneration; Thrombin; Thrombosis; Vascular Endothelial Growth Factor A

C-type natriuretic peptide (CNP), which is produced by vascular endothelial cells, exhibits anti-proliferative and anti-inflammatory effects. Cytotoxic T-lymphocytes may be involved in vein graft disease. Attenuation of vein graft disease necessitates a remodelling of the arterialized vein towards a more contractile phenotype which is characterized, among other factors, by the calponin amount. We investigated the effects of perivascularly applied CNP in a mouse model of vein graft disease.. C57BL6J mice underwent interposition of the inferior vena cava from isogenic donor mice into the common carotid artery using a previously described cuff technique. In the treatment group, 10(-6)mol/l of CNP were applied locally in pluronic gel. The control group did not receive local treatment. Grafts were harvested at 1, 2, 4, and 8 weeks and underwent morphometric analysis as well as immunohistochemical analysis.. In grafted veins without treatment (controls) median intimal thickness was 10 (6-29), 12 (8-40)microm, was 47 (12-58), and 79 (62-146)microm after 1, 2, 4 and 8 weeks, respectively. In the treatment groups, which received 10(-6)mol/l of CNP, the intimal thickness was 5 (3-6), 6 (4-15), 32 (5-54), and 43 (39-70)microm after 1, 2, 4 and 8 weeks, respectively. This reduction of intimal thickness was significant at 1, 2 and 8 weeks. Immunohistochemically, the reduction of intimal thickness was associated with a decreased infiltration of CD-8 positive cells and an increased amount of calponin in the CNP-treated grafts.. We conclude that perivascular application of CNP inhibits neointimal hyperplasia of vein grafts in a mouse model. These results suggest that CNP may have a therapeutic potential for the prevention of vein graft disease.

Topics: Administration, Topical; Animals; Calcium-Binding Proteins; Calponins; CD8-Positive T-Lymphocytes; Graft Occlusion, Vascular; Hyperplasia; Male; Mice; Mice, Inbred C57BL; Microfilament Proteins; Natriuretic Peptide, C-Type; Tunica Intima; Vena Cava, Inferior

To investigate the effects of C-type natriuretic peptide (CNP) gene transduction on neointimal hyperplasia and endothelial function after angioplasty.. Eighty-four rabbits were divided into 3 equal groups, namely normal control group, alkaline phosphatase gene transduction group and CNP gene transduction group. The rabbits in the latter two groups were given high-cholesterol diet 7 d before the experiment, followed by establishment of restenosis models by injuring the iliac artery and the specified gene transfer via retroviral vectors. Those in the normal control group were fed with normal diet. Before high-cholesterol diet and killing respectively, 2 ml venous blood samples were taken for testing blood lipid and serum CNP concentration. In the two groups with gene transduction, the injured rabbit iliac arteries were harvested for ex vivo vascular ring tension test, histological and pathological examinations, as well as immunohistochemistry analysis of CNP. The lumen area, neointimal thickness, neointimal area, ratio of intimal to medial area were measured by image analysis system.. There were no significant differences in blood lipid and serum CNP concentration between the two gene transduction groups at the same time points both before and after operation. In CNP gene transduction group, endothelium-dependent relaxation of the vascular rings was significantly improved in comparison with the other two groups (P<0.01), irrespective of L-Arg pretreatment, whereas endothelium-independent relaxation function varied little between the 3 groups (P>0.05). Poor relaxation function to Ach of the vascular rings was resulted after pretreatment with LMMA. CNP gene expression at the site of gene transfer was detected in the CNP gene transduction group and in 2 weeks after balloon injury, the neointimal thickness, neointimal area and ratio of the neointimal to tunica media area were markedly increased in the two gene transduction groups, but the measurements were significantly lower in CNP group (P<0.01).. CNP gene can be successfully transferred and effectively expressed at the injured site in the blood vessels to decrease the hyperplasia and significantly improve endothelial function after angioplasty.

Topics: Angioplasty, Balloon; Animals; Endothelium, Vascular; Genetic Therapy; Hyperplasia; Male; Natriuretic Peptide, C-Type; Rabbits; Tunica Intima

C-type natriuretic peptide (CNP) is an endogenous vascular modulator. In addition to vasodilation, CNP exerts multifunctions including anti-thrombus and anti-proliferation actions against vascular smooth muscle cells and myofibroblasts. Therefore, CNP is a potential therapeutic agent for the prevention of restenosis following angioplasty. The current study investigated whether local delivery of CNP, even at microgram levels about three orders of magnitude lower than doses (high milligram levels) used for systemic administration in the previous study, attenuates neointimal hyperplasia. The rabbit iliac artery was denuded, and then CNP (100 microg, n = 5) or control vehicle (n = 5) was administered locally over 20 min, via a local drug delivery catheter. During drug delivery, blood pressure was monitored with a high-fidelity micromanometer catheter. There was no significant decrease in arterial pressure immediately after the CNP administration. Four weeks after the treatment, computer-assisted morphometric analysis revealed significant reduction in the intimal area (CNP 0.44 +/- 0.27 versus control 0.96 +/- 0.20 mm2, p < 0.01), but no changes in the medial area (CNP 0.93 +/- 0.23 versus control 0.79 +/- 0.29 mm2, p = NS). This resulted in a significant decrease in the ratio of the intimal area to the medial area in CNP-treated vessels compared with control vessels (CNP 0.45 +/- 0.26 versus control 1.40 +/- 0.66, p < 0.05). Local delivery of a single low dose of CNP effectively inhibits neointimal hyperplasia with a minimal likelihood of compromising hemodynamics. Considering its multipotent actions and its role as an important regulator of the vascular system, this treatment may have a therapeutic advantage for clinical use.

Topics: Animals; Blood Pressure; Catheterization; Hyperplasia; Iliac Artery; Natriuretic Peptide, C-Type; Rabbits; Vasodilation