Absence of Heme Oxygenase-1 Affects Trophoblastic Spheroid Implantation and Provokes Dysregulation of Stress and Angiogenesis Gene Expression in the Uterus.

The enzyme heme oxygenase-1 (HO-1) is pivotal in reproductive processes, particularly in placental and vascular development. This study investigated the role of HO-1 and its byproduct, carbon monoxide (CO), in trophoblastic spheroid implantation. In order to deepen our understanding of the role of HO-1 during implantation, we conducted in vivo experiments on virgin and pregnant mice, aiming to unravel the cellular and molecular mechanisms. Using siRNA, HO-1 was knocked down in JEG-3 and BeWo cells and trophoblastic spheroids were generated with or without CO treatment. Adhesion assays were performed after transferring the spheroids to RL-95 endometrial epithelial cell layers. Additionally, angiogenesis, stress, and toxicity RT2-Profiler™ PCR SuperArray and PCR analyses were performed in uterine murine samples. HO-1 knockdown by siRNA impeded implantation in the 3D culture model, but this effect could be reversed by CO. Uteruses from virgin Hmox1-/- females exhibited altered expression of angiogenesis and stress markers. Furthermore, there was a distinct expression pattern of cytokines and chemokines in uteruses from gestation day 14 in Hmox1-/- females compared to Hmox1+/+ females. This study strongly supports the essential role of HO-1 during implantation. Moreover, CO appears to have the potential to compensate for the lack of HO-1 during the spheroid attachment process. The absence of HO-1 results in dysregulation of angiogenesis and stress-related genes in the uterus, possibly contributing to implantation failure.

Biomechanical evaluation of conventional anulus fibrosus closure methods required for nucleus replacement. Laboratory investigation.

OBJECT: Nucleus replacement implants became increasingly attractive as an alternative to fusion, discectomy, or total disc replacement. The goals of nucleus replacement are to restore disc height and flexibility and to preserve the anatomy. However, implant extrusions have been reported and are the major concern. In this study the authors investigated different conventional surgical methods for anulus closure: suture alone, and fibrin glue and cyanoacrylate glue, alone and with suture. METHODS: The in vitro testing was conducted using 30 lumbar spinal segments obtained from calves. In each specimen, an incision was made; the nucleus was removed and subsequently replaced by a collagen matrix. The incisions were treated with anulus closure methods in 5 groups of animals. Flexibility was assessed in a spine tester. Subsequently, specimens were exposed to cyclic fatigue loading by using a hydraulic loading frame. Specimens were excentrically loaded in sine waveform up to a maximum of 100,000 cycles with 4-24 Nm at 5 Hz while being rotated at 360 degrees/minute. RESULTS: Removal of the nucleus caused a significant loss of stability. The segmental stability could be restored after the implantation. Fatigue testing indicated that suturing was able to sustain 3400 cycles. Fibrin glue failed earlier than cyanoacrylate glue. Both combinations (suture with glue) provided longer stability to the anulus closure. CONCLUSIONS: The results suggested that closing the anulus incision with suture or fibrin glue alone might not be appropriate. The authors found that the best method was cyanoacrylate glue with suture. Although this method provided the longest duration of closure, it could not sustain the maximum number of fatigue cycles. Conventional methods could improve the outcome compared with using no closure. Nonetheless, the authors' findings highlight the demand for an appropriate anulus reconstruction method or device with good long-term reliability.