Femtosecond pulsed laser microscopy: a new tool to assess the in vitro delivered dose of carbon nanotubes in cell culture experiments

M2 macrophages enhance endometrial cell invasiveness by promoting collective cell migration in uterine adenomyosis

RESEARCH QUESTION

Are M2 macrophages implicated in endometrial invasiveness in adenomyosis?

DESIGN

Seventeen formalin-fixed paraffin-embedded uterine samples and 16 fresh endometrial biopsies were collected from women with or without adenomyosis. Double immunofluorescence was performed to determine the predominant macrophage population in adenomyosis between M1 and M2 phenotypes. The invasion capacity of endometrial cells was assessed by invasion assays and quantitative polymerase chain reaction for genes involved in cell motility and epithelial-mesenchymal transition (EMT). Specific mechanisms of invasion were investigated by immunohistochemistry for E-cadherin, N-cadherin and matrix metalloproteinase 9 (MMP9).

RESULTS

Only M2 macrophages were found to accumulate in adenomyosis, in higher numbers in both eutopic endometrium (P = 0.0109) and lesions (P = 0.0267) than healthy tissue. Co-culture with M2 macrophages significantly boosted invasion capacity in endometrial epithelial (P = 0.0002; P = 0.002) and stromal cells (P = 0.0469; P = 0.0047) from both adenomyosis patients and healthy controls. No gene expression differences indicating EMT were noted, either between co-cultured and control cells, or between healthy and adenomyotic cells. E- and N-cadherin protein expression did not differ significantly between endometrium from adenomyosis subjects and healthy tissue but MMP9 expression was increased in eutopic stroma from adenomyosis patients (P = 0.0492). In adenomyosis, both E-cadherin (P = 0.0379) and N-cadherin (P = 0.0196) were more extensively expressed in basal glands than functional glands.

CONCLUSIONS

M2 macrophages accumulate in adenomyosis and enhance invasion capacity of adenomyotic and even healthy endometrial cells, implying that macrophage infiltration alone may be sufficient to promote the disease. This study failed to detect any changes pointing to EMT, suggesting an alternative mode of invasion. Strong E- and N-cadherin-positive intercellular junctions in basal (invasive) glands suggest the involvement of collective cell migration in the invasion process of endometrium.

Genotoxicity of multi-walled carbon nanotube reference materials in mammalian cells and animals

Carbon nanotubes (CNTs) were the first nanomaterials to be evaluated by the International Agency for Research on Cancer (IARC). The categorization as possibly carcinogenic agent to humans was only applicable to multi-walled carbon nanotubes called MWCNT-7. Other types of CNTs were not classifiable because of missing data and it was not possible to pinpoint unique CNT characteristics that cause cancer. Importantly, the European Commission's Joint Research Centre (JRC) has established a repository of industrially manufactured nanomaterials that encompasses at least four well-characterized MWCNTs called NM-400 to NM-403 (original JRC code). This review summarizes the genotoxic effects of these JRC materials and MWCNT-7. The review consists of 36 publications with results on cell culture experiments (22 publications), animal models (9 publications) or both (5 publications). As compared to the publications in the IARC monograph on CNTs, the current database represents a significant increase as there is only an overlap of 8 publications. However, the results come mainly from cell cultures and/or measurements of DNA strand breaks by the comet assay and the micronucleus assay (82 out of 97 outcomes). A meta-analysis of cell culture studies on DNA strand breaks showed a genotoxic response by MWCNT-7, less consistent effect by NM-400 and NM-402, and least consistent effect by NM-401 and NM-403. Results from other in vitro tests indicate strongest evidence of genotoxicity for MWCNT-7. There are too few observations from animal models and humans to make general conclusions about genotoxicity.