The role of G-protein-coupled membrane estrogen receptor in mouse Leydig cell function-in vivo and in vitro evaluation

In this study, G-coupled estrogen receptor (GPER) was inactivated, by treatment with antagonist (G-15), in testes of C57BL/6 mice: immature (3 weeks old), mature (3 months old) and aged (1.5 years old) (50 μg/kg bw), as well as MA-10 mouse Leydig cells (10 nM/24 h) alone or in combination with 17β-estradiol or antiestrogen (ICI 182,780). In G-15-treated mice, overgrowth of interstitial tissue was found in both mature and aged testes. Depending on age, differences in structure and distribution of various Leydig cell organelles were observed. Concomitantly, modulation of activity of the mitochondria and tubulin microfibers was revealed. Diverse and complex GPER regulation at the mRNA level and protein of estrogen signaling molecules (estrogen receptor α and β; ERα, ERβ and cytochrome P450 aromatase; P450arom) in G-15 Leydig cells was found in relation to age and the experimental system utilized (in vivo and in vitro). Changes in expression patterns of ERs and P450arom, as well as steroid secretion, reflected Leydig cell heterogeneity to estrogen regulation throughout male life including cell physiological status.We show, for the first time, GPER with ERs and P450arom work in tandem to maintain Leydig cell architecture and supervise its steroidogenic function by estrogen during male life. Full set of estrogen signaling molecules, with involvement of GPER, is crucial for proper Leydig cell function where each molecule acts in a specific and/or complementary manner. Further understanding of the mechanisms by which GPER controls Leydig cells with special regard to male age, cell of origin and experimental system used is critical for predicting and preventing testis steroidogenic disorders based on perturbations in estrogen signaling.

Identification of perivascular and stromal mesenchymal stem/progenitor cells in porcine endometrium

Mammalian uterus contains a population of mesenchymal stem/progenitor cells that likely contribute to endometrial regeneration during each reproductive cycle. In human and mouse, they reside in perivascular, epithelial and stromal compartments of the endometrial functionalis and basalis. Here, we aimed to identify tissue resident cells expressing mesenchymal stem cell markers CD29, CD44, CD90, CD105, CD140b and CD146 in the porcine endometrium. We used single immunofluorescence and Western blotting. Each of these markers was detected in small cells surrounding endometrial blood vessels. CD105 and CD146 were also expressed in single stromal cells. A few stromal and perivascular cells showed the presence of pluripotency marker Oct4 in the cytoplasm, but not in the nucleus, which may imply they are not truly pluripotent. Endometrial cell cultures were examined for the expression of CD29, CD44, CD90, CD105 and CD140b proteins and tested in wound-healing assay and culture model of chemotaxis. In conclusion, our results demonstrate perivascular location of prospective mesenchymal stem/progenitor cells in the porcine endometrium and may suggest that stromal CD105⁺ and CD146⁺ cells represent more mature precursors originating from their perivascular ancestors.

Interpretation of Post-operative Distal Humerus Radiographs After Internal Fixation: Prediction of Later Loss of Fixation

PURPOSE

Stable fixation of distal humerus fracture fragments is necessary for adequate healing and maintenance of reduction. The purpose of this study was to measure the reliability and accuracy of interpretation of postoperative radiographs to predict which implants will loosen or break after operative treatment of bicolumnar distal humerus fractures. We also addressed agreement among surgeons regarding which fracture fixation will loosen or break and the influence of years in independent practice, location of practice, and so forth.

METHODS

A total of 232 orthopedic residents and surgeons from around the world evaluated 24 anteroposterior and lateral radiographs of distal humerus fractures on a Web-based platform to predict which implants would loosen or break. Agreement among observers was measured using the multi-rater kappa measure.

RESULTS

The sensitivity of prediction of failure of fixation of distal humerus fracture on radiographs was 63%, specificity was 53%, positive predictive value was 36%, the negative predictive value was 78%, and accuracy was 56%. There was fair interobserver agreement (κ = 0.27) regarding predictions of failure of fixation of distal humerus fracture on radiographs. Interobserver variability did not change when assessed for the various subgroups.

CONCLUSIONS

When experienced and skilled surgeons perform fixation of type C distal humerus fracture, the immediate postoperative radiograph is not predictive of fixation failure. Reoperation based on the probability of failure might not be advisable.

TYPE OF STUDY/LEVEL OF EVIDENCE

Diagnostic III.