Administration of perivascular cyanoacrylate for the prevention of cellular damage in saphenous vein grafts: an experimental model

A New Method Involving Percutaneous Application in the Treatment of Deep Venous Insufficiency: An Experimental Study With Internal Compression Therapy in a Porcine Model

INTRODUCTION

To study the efficiency of internal compression therapy (ICT), a new and promising method of treatment for deep venous insufficiency, how that efficiency is achieved, and its potential side-effects, in a porcine model.

MATERIAL AND METHODS

The femoral vein diameters of 4 pigs were first measured. ICT was then applied such as to reduce the diameter of these veins by 50%. The femoral vein diameters of 2 pigs were re-measured after 1 month. The femoral vein and its surrounding tissue were excised for immunohistopathological and genetic examination. The same procedures were applied to the remaining 2 pigs 3 months subsequently. Collagen I and IV immunohistochemical staining and Masson's trichrome and Alcian blue histochemical staining were applied during immunohistopathological examination. Collagen I, III, and IV and connective tissue growth factor (CTGF) mRNA expressions were examined for genetic examination.

RESULTS

The femoral vein diameters decreased by approximately 50% after ICT application. This decrease persisted after the first and third months. Histopathological examination revealed loose connective tissue around the venous tissue after the operation, particularly in the third month, together with perivascular fibrosis and increased collagen in connective tissue. No difference was observed between regions with and without ICT application in terms of mucinous degeneration, an indicator of tissue injury, during Alcian blue staining. Genetic examination revealed an increase in collagen I and IV and CTGF mRNA expression in perivascular tissue resulting from ICT application.

CONCLUSION

ICT is effective both in terms of creating a durable tissue around the vein and of increasing collagen tissue and stimulating fibrosis, and has no deleterious side-effects on tissue.

Debonding Shear Strength of Orthodontic Tubes Bonded to Skeletal Anchorage Miniplates with Different Agents

Introduction:

Most miniplates used for skeletal anchorage lack built-in orthodontic devices. To address this issue, orthodontists must use creative solutions, such as bonding buttons, brackets, or tubes directly to the miniplates, thus making them more versatile devices that provide a wider range of tooth movement possibilities. The purpose of the present study was to ascertain the debonding strength in Megapascals (MPa) of orthodontic accessories bonded to skeletal anchorage miniplates with different bonding agents.

Methods:

Forty specimens were divided into two equal groups by bonding agent: Group 1, resin (Transbond XT®, 3M ESPE); Group 2, cyanoacrylate (Scotchbond®, 3M ESPE). Shear strength testing was performed in an EMIC DL-2000 universal testing machine.

Results:

The results obtained were 2.28 ± 0.44 MPa for Group 1 and 4.90 ± 0.76 MPa for Group 2. The Kolmogorov-Smirnov test was used to assess the normality of data distribution. Student's t-test was used to compare means in the response variable.

Conclusion:

A statistically significant difference was observed between groups. However, both bonding agents provided strength in excess of that needed for secure orthodontic tooth movement.

The placental growth factor attenuates intimal hyperplasia in vein grafts by improving endothelial dysfunction

Saphenous vein grafts (SVG) patency is limited by intimal hyperplasia (IH) caused by endothelial dysfunction. This study aimed to explore the effect of placental growth factor (PlGF) on the endothelial function of SVG. In rat models of external jugular vein-carotid artery graft treated with PlGF or saline hydrogel, PlGF inhibited vein graft IH (day 28: 12.0 ± 1.9 vs. 61.7 ± 13.1 μm, P < 0.001), promoted microvessel proliferation (day 14: 33.3% 3+ vs. 50.0% 2+, P = 0.03), and increased nitric oxide (NO) production (P < 0.05 on days 1/3/5) and NO synthase (NOS) expression by immunohistochemistry. In human umbilical vein endothelial cells (HUVECs) cultured under hypoxia and treated or not with PlGF, PlGF restored the survival (50 ng/ml PlGF, 48 h: 91.7 ± 0.6% vs. 84.9 ± 0.5%, P < 0.01), migration (by Matrigel assay), and tube formation ability (junctions, tubules, and tubule total length; all P < 0.01) of HUVECs after hypoxia. PlGF increased NO production through increased eNOS expression (P < 0.05), without changes in iNOS expression. The mRNA expression of eNOS decreased after the addition of the PI3K inhibitor LY294002 (P < 0.05). PlGF promoted the protein expression of eNOS by up-regulating AKT, and the AKT and eNOS protein levels were decreased after adding LY294002 (all P < 0.05). In conclusion, PlGF is a candidate for the inhibition of IH in SVG after coronary artery bypass graft. The effects of PlGF are mediated by the upregulation of the eNOS mRNA and protein through the PI3K/AKT signaling pathway. PlGF promotes the secretion of NO by endothelial cells and thereby reduces the occurrence and development of IH.