The Effect of Circuit Surface Area on CD11b(mac‐1) Expression in a Rat Recirculation Model

Abstract

The aim of the study was to assess the effect of exposed surface area of diethylhexylphthalate plasticized polyvinylchloride (PVC) on the expression of the adhesion molecule CD11b(mac-1) on neutrophils and to determine whether there is any apparent advantage in the current trend in reducing circuit surface area in terms of neutrophil activation. The study was carried out using a parallel plate rodent recirculation biomaterial testing model on 4 groups of 10 adult male Sprague Dawley rats weighing between 350 and 450 g. One group comprised the control group in which there was no biomaterial exposure. In the remaining 3 groups, the animals were subjected to either high (48 cm2), intermediate (24 cm2), or low (12 cm2) biomaterial surface area exposure. The parallel plate test cell was connected to the right femoral circulation and recirculation initiated at a flow rate of 1.5 ml/min for a period of 60 min. Blood samples were taken at 0, 30, and 60 min for the assessment of CD11b expression. Cd11b was assessed using flow cytometric analysis on neutrophils. The results demonstrated that there was a surface area related effect in the upregulation of CD11b. The difference at the terminal sample point between the highest surface area group (293.95 +/- 18.57%) and the low surface area group (133.80 +/- 49.31%) was highly statistically significant (p < 0.001). These results demonstrate that there may be some gain in terms of reduced inflammatory response from reducing the exposed surface area of PVC in extracorporeal perfusion circuits.

Influence of Lipid Type on Bis (2‐ethylhexyl)phthalate (DEHP) Leaching From Infusion Line Sets in Parenteral Nutrition

“…This proinflammatory effect is directly proportional to the contact surface area and to the DEHP content at the PVC surface. 17,18 The olive oil IVFE contains 65% oleic acid, which is a monounsaturated fatty acid that improves resistance to lipid peroxidation and thus plays a role in reducing oxidative stress. 19 This antioxidant capacity also hinges on the fact that olive oil is rich in α-tocopherol, which is the most active vitamin E isomer in vivo.…”

Inflammatory Response of Rat and Human Neutrophils Exposed to Di‐(2‐ethyl‐hexyl)‐phthalate‐Plasticized Polyvinyl Chloride

“…Tubes containing blood were placed on ice and flow cytometric analysis was carried out within one hour of blood sampling. The technique used has been described by our group previously (4,6) and is now a standard and established technique that works well in the human and rat models. In general, blood was incubated with monoclonal antibody directed against mouse CD11b at a final antibody concentration of 10 μg/ml.…”

“…Blood‐biomaterial contact during clinical extracorporeal circulation, for example cardiopulmonary bypass (CPB), has been implicated in the initiation of inflammatory processes in patients undergoing such a therapeutic procedure (1–3). In a recent series of studies, we suggested that DEHP, present as the plasticizer in PVC tubing for CPB applications, initiates an inflammatory response that can be characterized by the expression of the integrin CD11b on isolated neutrophils in rats undergoing periods of extracorporeal circulation (4,5). In these studies, we further demonstrated that, by methanol washing the surface material in an attempt to reduce the amount of plasticizer present on the surface, it was possible to attenuate the inflammatory response (6).…”

Phthalates in food and medical devices

“…These findings suggest that medical devices may induce respiratory inflammation and heighten the needs for additional studies on phthalates related inflammatory responses. They are particularly concerning given the widespread use of phthalates in medical devices and equipment (Gourlay et al, 2001). …”