Pushing the envelope in biomaterial research: initial results of prosthetic coating with stem cells in a rat model.

BACKGROUND: Coating prosthetic for hernia repair with a patient's own cells could improve biocompatibility by decreasing inflammation and adhesion formation and by increasing tissue ingrowth and resistance to infection. The objective of this study was to prove the feasibility of prosthetic coating with stem cells and to assess its resistance to adhesion formation when implanted in an animal model. METHODS: Adult Lewis rat bone marrow stem cells were harvested and cultured. Stem cells were then implanted on three different prosthetics. The prosthetic with the best stem cell adherence was implanted intraperitoneally into six adult rats. Untreated prosthetic was implanted in control animals (n = 12). After 2 weeks, intra-abdominal adhesions were graded using an adhesion scoring scale by two surgeons who were blinded to the animal group. Data were analyzed using the Wilcoxon rank-sum test. RESULTS: Stem cells demonstrated the best adherence and growth on polyglactin prosthetics. After implantation, the stem cell-coated polyglactin prosthetic had <25% of its surface area covered with adhesions in five (83%) samples, whereas the control polyglactin group had only one sample (8.3%) with <25% adhesions, and seven of its samples (58.3%) had >50% surface area adhesions (p < 0.05). CONCLUSIONS: The feasibility of hernia prosthetic coating with stem cells was demonstrated. Furthermore, stem-cell coated polyglactin prosthetic exhibited improved biocompatibility by decreasing adhesion formation in an animal model. Further study is needed to determine the factors that promote stem cell adherence to prosthetics and the in vivo prosthetic biomechanics after stem cell coating. This work is underway in our laboratory.

Screening for oxygen sensitivity in U.S. Navy combat swimmers.

The United States Naval Special Warfare Community uses oxygen tolerance testing to screen Navy combat swimmer candidates for sensitivity to the toxic effects of hyperbaric oxygen (HBO2). Between 1976 and 1997, 6,250 oxygen-tolerance tests were performed at the Naval Special Warfare Center and Naval Special Warfare Group One. Our review of these data found only six episodes of O2 toxicity for an incidence of 0.096%, an incidence considerably lower than the rate of 1.9% reported in an earlier review using data from the Naval Safety Center. Additionally, we reviewed data from the Naval Safety Center from 1986 to 1997 and found only one episode of O2 toxicity among 157,930 LAR V dives. Many factors other than individual sensitivity to HBO2 may contribute to the occurrence of O2 toxicity episodes during combat swimmer operations. The authors conclude that O2 tolerance testing of U. S. Navy SEAL candidates is not a useful screening test and recommend discontinuation of this test.