Bleed of and Biologic Response to Triglyceride Filler Used in Radiolucent Breast Implants

Abstract

Radiolucent breast implants filled with triglyceride oil have recently entered limited clinical trials. To investigate the questions of oil bleed and the fate of triglycerides that might escape from ruptured breast implants, experiments reported here used peanut oil labeled with radioisotopes so that it could be traced in the urine, feces, and organs of two groups of rabbits. In one experiment, 18 rabbits were implanted with peanut oil-filled implants labeled with tritium to determine whether triglycerides diffuse across silicone elastomer shells. In another experiment, 19 rabbits were injected with 14C-labeled peanut oil to study what might happen to the oil if an implant ruptures. At the end of the follow-up period, we measured radioisotope levels in tissue samples taken from the periprosthetic capsule or injection site of each rabbit, as well as from major organs and the subcutaneous fat on the dorsum opposite the experimental site. One experiment revealed that triglycerides do bleed across the implant shells. Tritium levels were highest in the implant capsule, the omentum, the aorta, and the subcutaneous fat on the nonexperimental side. In the experiment simulating implant rupture, 14C levels were above the background radiation count at the injection site and in the same tissue sites as in the bleed experiment. Both in vivo radiolabeling studies indicate that triglycerides freed from implants by means of bleed or rupture would be absorbed, metabolized, and either excreted or redistributed to the body's normal fat storage sites if they are not needed for energy. In a third in vitro experiment, triglyceride oil specimens were inoculated with various microorganisms associated with wound infections: Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Staphylococcus epidermidis, and diphtheroids. The data demonstrate that neutral triglycerides used as a breast implant filler do not support growth of common infection-producing bacteria and suggest that triglycerides may have bactericidal properties.

Trilucent Breast Implants: Voluntary Removal following the Medical Device Agency Recommendation. Report on 115 Consecutive Patients

“…22 Other studies found the bleeding rate to be as high as 5 percent of the implant content per year. 13,23 The consequent underfilled implant could explain why rippling is so common in these women. Another possible explanation of the rippling in our series may be related to the textured elastomer, which was extremely adherent to the capsule.…”

“…12 A study in an animal model showed that no harmful effects were associated with use of this new filler material. 13 Other studies analyzed the oil collected from an explanted implant and demonstrated the formation of lipid peroxides. 14 In vitro investigations have shown that lipid peroxidation can lead to DNA alterations.…”

What Exactly Was Wrong with the Trilucent Breast Implants? A Unifying Hypothesis

“…4,[22][23][24][25] The soybean oil used in Trilucent implants consisted of 86% unsaturated fatty acids and less than 1% free fatty acids. Polyunsaturated and free fatty acids are susceptible to auto-oxidation, eventually leading to the formation of hydroperoxides.…”

“…[35][36][37] Given the known data on silicone elastomer degeneration secondary to lipid infiltration and the reports of bleeding of triglyceride filler in radiolucent breast implants, it is only logical to assume that triglycerides, being lipophilic compounds, are absorbed by the silicone elastomer, resulting in a loss of shell integrity because of a decrease in tensile strength and also resulting in increased permeability. 22,33 Peters and Smith, 38 in an invited discussion, reviewed lipid absorption and infiltration in various surfaces and ended by stating, "If lipid absorption proves to be a significant problem, then new prostheses containing vegetable or other oils will require a more critical evaluation. "…”

Lay Experts and the Politics of Breast Implants

“…No clinical trials of them were held prior to market approval in Europe, and after their withdrawal from the market the post-market trial was halted. 60 Subsequently, the company with responsibility for the Trilucent implant (AEI Inc.) has enrolled women who have had them into a research program to look at the long-term effects. 61 Interestingly, in the US, a clinical trial using Trilucent implants was set up (but not yet published), although the device was never approved for commercial use there.…”