The effect of bovine serum albumin-glutaraldehyde and polyethylene glycol polymer on neointimal hyperplasia in rabbit carotid artery anastomosis

Solid-Phase Polymerization Using Anion-Exchange Resin Can Almost Completely Crosslink Hemoglobin to Prepare Hemoglobin-Based Oxygen Carriers

Introduction

A limitation of hemoglobin-based oxygen carriers (HBOCs) as oxygen therapeutics is unpolymerized hemoglobin, which induces vasoconstriction leading to hypertension. The removal of unpolymerized hemoglobin from polymerized hemoglobin (PolyHb) is complex, expensive, and time-consuming.

Methods

Herein, we developed a method to completely polymerize hemoglobin almost without unpolymerized hemoglobin. Hemoglobin was adsorbed on the anion-exchange resin Q Sepharose Fast Flow or DEAE Sepharose Fast Flow, and acetal, a crosslinker prepared from glutaraldehyde and ethylene glycol, was employed to polymerize the hemoglobin. The polymerization conditions, including reaction time, pH, resin type, and molar ratios of glutaraldehyde to ethylene glycol and hemoglobin to acetal, were optimized. The blood pressure and blood gas of mice injected with PolyHb were monitored as well.

Results

The optimal polymerization condition of PolyHb was when the molar ratio of glutaraldehyde to ethylene glycol was 1:20, and the molar ratio of 10 mg/mL hemoglobin adsorbed on anion-exchange resin to glutaraldehyde was 1:300 for 60 min. Under optimized reactive conditions, hemoglobin was almost completely polymerized, with <1% hemoglobin remaining unpolymerized, and the molecular weight of PolyHb was more centrally distributed. Furthermore, hypertension was not induced in mice by PolyHb, and there were also no pathological changes observed in arterial oxygen, blood gas, electrolytes, and some metabolic indicators.

Conclusion

The findings of this study indicate that the use of solid-phase polymerization and acetal is a highly effective and innovative approach to HBOCs, resulting in the almost completely polymerized hemoglobin. These results offer promising implications for the development of new methods for preparing HBOCs.

The effect of bovine serum albumin-glutaraldehyde and polyethylene glycol polymer on local tissue reaction and inflammation in rabbit carotid artery anastomosis

Objectives

In addition to the hemostatic properties of hemostatic agents, the investigation of their immunogenic properties, their local effects on application area has been the subject of many experimental studies. There are limited data on the inflammatory effects of Bovine serum albumin-glutaraldehyde and Polyethylene glycol polymer. Therefore, we investigated the effects of these agents on tissue reactions and inflammation in rabbit carotid artery anastomosis in our experimental study.

Methods

Twenty-one New Zealand male rabbits were randomly divided into three groups. The right carotid artery anastomosis was performed on the control group after transection. Hemostatic agents were applied locally to other two groups separately after transection and anastomosis. At the end of 28 days, the type of inflammation, inflammatory cell infiltration, degree of inflammation, and amount of residual adhesives were examined and compared statistically.

Results

Cell infiltrations associated with inflammation on the anastomosis site (eosinophils, epithelioid/giant cells, lymphocytes, and plasma cells) and inflammation grade in the groups of hemostatic agents were significantly lower compared to the control group ( p < .05). There was no difference between the hemostatic agents. While mild inflammation (61.9%) was dominant in the groups of hemostatic agents, moderate inflammation (85.7%) was more common in the control group. No severe inflammation was observed in any of the three groups. Residual sealant grade between hemostatic agents did not differ significantly.

Conclusions

When inflammation and tissue reactions of the 4th week were evaluated, it was determined that both hemostatic agents did not cause severe inflammation. However, comparative results at multiple time intervals are needed due to the dynamic process of inflammation.