Effect of gelatin methacryloyl hydrogel on healing of the guinea pig vaginal wall with or without mesh augmentation.

Introduction and hypothesisThe aims of this study were to evaluate the effectiveness of gelatin methacryloyl as an adjunct to anterior vaginal wall injury with or without vaginal mesh compared with traditional repair with suture.MethodsVirginal cycling Hartley strain guinea pigs (n = 60) were randomized to undergo surgical injury and repair using either polyglactin 910 suture or gelatin methacryloyl for epithelium re-approximation or anterior colporrhaphy with mesh augmentation using either polyglactin 910 suture or gelatin methacryloyl for mesh fixation and epithelium re-approximation. Noninjured controls (n = 5) were also evaluated. After 4 days, 4 weeks, or 3 months, tissues were analyzed by hematoxylin & eosin in addition to immunolabeling for macrophages, leukocytes, smooth muscle, and fibroblasts.ResultsSurgical injury repaired with suture was associated with increased inflammation and vessel density compared with gelatin methacryloyl. Vimentin and α-smooth muscle actin expression were increased with gelatin methacryloyl at 4 days (p = 0.0026, p = 0.0272). There were no differences in changes in smooth muscle or overall histomorphology after 3 months between the two closure techniques. Mesh repair with suture was also associated with increased inflammation and vessel density relative to gelatin methacryloyl. Quantification of collagen content by picrosirius red staining revealed increased thick collagen fibers throughout the implanted mesh with gelatin methacryloyl compared with suture at 4 weeks (0.62 ± 0.01 μm2 vs 0.55 ± 0.01, p = 0.018). Even at the long-term time point of 3 months, mesh repair with suture resulted in a profibrotic encapsulation of the mesh fibers, which was minimal with gelatin methacryloyl. Smooth muscle density was suppressed after mesh implantation returning to baseline levels at 3 months regardless of fixation with suture or gelatin methacryloyl.ConclusionsThese results suggest that gelatin methacryloyl might be a safe alternative to suture for epithelium re-approximation and anchoring of prolapse meshes to the vagina and may improve chronic inflammation in the vaginal wall associated with mesh complications

A Novel Isoform of Microphthalmia-Associated Transcription Factor Inhibits IL-8 Gene Expression in Human Cervical Stromal Cells

Cervical ripening during pregnancy is a profound change in cervix structure and function characterized by increases in the proinflammatory cytokine IL-8 and dissolution of the cervical extracellular matrix. Relatively little is known about the molecular mechanisms that underlie these events. Here, we report identification of a novel isoform of micropthalmia-associated transcription factor in human cervical stromal cells (MiTF-CX) that is down-regulated 12-fold during cervical ripening and that represses expression of IL-8. Ectopic expression of MiTF-CX in human cervical stromal cells resulted in substantial suppression of endogenous IL-8 mRNA and protein expression, whereas expression of dominant negative MiTF-CX mutants with impaired DNA binding resulted in dramatic increases in IL-8 production. Gel shift, reporter gene, and chromatin immunoprecipitation assays revealed one strong binding site (E-box -397 CACATG-391) in the human IL-8 promoter that was crucial for mediating transcriptional repression by MiTF-CX. Moreover, we show that MiTF-CX expression in the cervix was itself positively autoregulated via two E-box motifs within a 2.1-kb promoter fragment. We therefore propose that maintenance of cervical competency during pregnancy is an active process maintained through suppression of IL-8 by the transcription factor MiTF-CX. During cervical ripening, loss of MiTF-CX would result in significant up-regulation of IL-8 mRNA and protein synthesis, thereby leading to recruitment and activation of leukocytes within the cervix and dissolution of the extracellular matrix