In vitro analysis of ovarian cancer response to cisplatin, carboplatin, and paclitaxel identifies common pathways that are also associated with overall patient survival.

BACKGROUND: Carboplatin and cisplatin, alone or in combination with paclitaxel, have similar efficacies against ovarian cancer (OVCA) yet exhibit different toxicity profiles. We characterised the common and unique cellular pathways that underlie OVCA response to these drugs and analyse whether they have a role in OVCA survival. METHODS: Ovarian cancer cell lines (n=36) were treated with carboplatin, cisplatin, paclitaxel, or carboplatin-paclitaxel (CPTX). For each cell line, IC(50) levels were quantified and pre-treatment gene expression analyses were performed. Genes demonstrating expression/IC(50) correlations (measured by Pearson; P<0.01) were subjected to biological pathway analysis. An independent OVCA clinico-genomic data set (n=142) was evaluated for clinical features associated with represented pathways. RESULTS: Cell line sensitivity to carboplatin, cisplatin, paclitaxel, and CPTX was associated with the expression of 77, 68, 64, and 25 biological pathways (P<0.01), respectively. We found three common pathways when drug combinations were compared. Expression of one pathway ('Transcription/CREB pathway') was associated with OVCA overall survival. CONCLUSION: The identification of the Transcription/CREB pathway (associated with OVCA cell line platinum sensitivity and overall survival) could improve patient stratification for treatment with current therapies and the rational selection of future OVCA therapy agents targeted to these pathways.

A new method for the preservation of aortic valve homografts.

BACKGROUND AND AIM OF THE STUDY: Aortic valve homografts were treated with 50% ethanol and glycerol followed by freeze-drying (D-Hydro). Comparative results of fresh versus D-Hydro-treated aortic roots implanted for up to nine months in the descending aorta of sheep with induced aortic regurgitation (AR) are reported. METHODS: Six fresh and six D-Hydro valves were implanted in 12 sheep for three, six and nine months, and echocardiography and pressures were taken at surgery and sacrifice. Tissue sections were stained with hematoxylin and eosin, von Kossa, Masson's trichrome, Movat's pentachrome, von Willebrand factor, CD3 (a T-cell marker) and smooth muscle alpha-actin. RESULTS: No grafts had increased gradients after implantation, or at sacrifice. At explantation, fresh homografts showed early pannus formation followed by thrombus, annular dilatation and wall calcification. Leaflets were thickened and progressively retracted. All had severe AR. The appearance of D-Hydro-treated homografts was normal, except for mild leaflet retraction in three, resulting in AR (in two animals the induced AR had healed). Histologically, a T-cell-mediated reaction was evident in the fresh homografts, and collagen distortion was noted. Calcification was present in all fresh specimens and was severe at nine months. D-Hydro roots showed only minor calcification in the six-month samples. Normal collagen, and a complete layer of von Willebrand factor-stained cells were present at three months. At nine months, cell rehabitation extended for two-thirds of the leaflets (alpha-actin +). The inflammatory reaction was very mild, with CD3+-stained cells absent in most samples. CONCLUSION: Aortic valve homografts treated with the D-Hydro freeze-drying method performed better than fresh homografts due to the absence of thrombus and annulus dilatation, limited calcification, and rehabitation of the aortic wall and parts of the leaflet by myofibroblasts, as well as the presence of a complete endothelial layer on the aortic wall and leaflet.

A study of the junction between glutaraldehyde-treated allogeneic aorta and host aorta.

BACKGROUND AND AIM OF THE STUDY: Stentless aortic valve bioprostheses have become popular because of their superior hemodynamics and expected increased durability. However, the stentless bioprosthesis differs from stented valves in that glutaraldehyde (GA)-treated tissue is implanted in direct contact with the native aorta. The effect of GA-treated tissue on host tissue has not been reported. METHODS: In order to analyze the effect of GA in the healing process, sheep descending aortic conduits treated with 0.625% GA were inserted in the descending thoracic aorta of 10 adult sheep. The implants were removed after 4, 5, 10, 12, 15, 25, 30, 32, 60 and 120 days. The upstream and downstream junctions were evaluated macro- and microscopically, and by immunohistology for smooth muscle cell alpha-actin and von Willebrand factor. RESULTS: By day 60 of implantation, the GA-treated conduits were calcified. By days 60 and 120, the calcification had spread to the host aorta, and was seen as foci of calcification in the junctional area. Acellular areas were also seen in the host aorta near the anastomosis. A fibrotic layer spanning the abluminal aspect of the junction between the implant and host aorta was present at day 4 and continued through 120 days. This layer was characterized by a progressive increase in collagenous matrix and cellularity, as well as new blood vessel formation. The luminal aspect of the junction had a neointimal layer of variable thickness containing alpha-actin-expressing cells covered by a monolayer of von Willebrand factor-expressing cells, seen at 15-30 days and present through 120 days. CONCLUSION: In our model, implanting GA-fixed tissue in direct contact with living tissues resulted in cell death and calcification of host tissue within 60 days. The integrity of the junction did not appear to be compromised. This may be of interest in light of the increased popularity of the stentless aortic bioprosthesis.

Behavior of vital and killed autologous pericardium in the descending aorta of sheep.

OBJECTIVES: Cardiovascular implants of fresh autologous pericardium produced mixed results including fibrosis with retraction or thinning and dilatation. The reasons for these differences are unknown but may involve activation of cells intrinsic to the tissue implant. To better understand the behavior of autologous pericardial implants, we studied the outcomes of vital pericardium (fresh) versus ethanol-killed pericardium. METHODS: Fresh and ethanol-killed autologous pericardium was transplanted as a patch, a conduit, or a rectangular flap bisecting the lumen in the descending aorta of sheep. The implants, recovered at 1, 5, 10, 15, and 30 days, were evaluated macroscopically and microscopically and by immunohistologic studies. RESULTS: Fresh implants showed good preservation with fibrin deposition on day 15. Microscopically, cells positive for alpha-actin and von Willebrand-related antigen appeared in the fibrin by day 10. By day 30 the flap was fibrotic and retracted whereas the patch and conduit retained their original appearance on the luminal aspect. An endothelium-like layer expressing von Willebrand-related antigen was present in the patch and conduit but absent in the flap. In contrast, the ethanol-killed implants were free of fibrin by day 10. By day 30, there were no signs of fibrosis or retraction, and a surface layer of cells expressing von Willebrand-related antigen, characteristic of endothelial cells, was present on all implants. All ethanol-killed implants were repopulated by host cells. CONCLUSION: The transluminal flap is an interesting model for studying the behavior of intraluminal autologous pericardial cardiovascular implants. Killing of the pericardial implants alleviated the fibrosis and tissue retraction observed with fresh flap implants.

Generation of antiserum to specific epitopes.

The ability to prevent disease by immunization with subunit vaccines that incorporate specific epitopes was demonstrated by DiMarchi et al. (1), who used a synthetic peptide to protect cattle against foot-and-mouth disease. However, generation of antibody to peptide antigens is often difficult owing to the small molecular mass and limited chemical complexity. We tested the hypothesis that recombinant DNA and synthetic peptide techniques would make it possible to stimulate vigorous immune responses to specific epitopes of an outer membrane protein of Neisseria gonorrhoeae. The MtrC AP1 sequence from the invariant MtrC gonococcal lipoprotein was genetically fused to maltose binding protein. The resultant fusion protein was used as the primary immunogen to stimulate MtrC AP1-specific antiserum. To enhance antibody production specific to MtrC AP1, boosting immunizations were performed with synthetic MtrC AP1 sequence contained in a multiple antigenic peptide system immunogen. The MtrC AP1-specific antiserum strongly recognized the MtrC protein on Western blots and appeared to bind native MtrC protein in situ. The generation of antibody in this fashion provides the technology to produce antibody to defined epitopes of any protein, including those found in the gonococcal outer membrane. The ability of those antibodies to inhibit bacterial growth or to activate complement protein can then be tested.