Correction to: Expression of matrix metalloproteinase 12 is highly specific for non-proliferating invasive trophoblasts in the first trimester and temporally regulated by oxygen-dependent mechanisms including HIF-1A.

In the original publication, the contribution of Dr. Christian Eyth as equal first author was not indicated. This has been corrected confirming that U. Hidden and C. Eyth contributed equally to this work.

Expression of matrix metalloproteinase 12 is highly specific for non-proliferating invasive trophoblasts in the first trimester and temporally regulated by oxygen-dependent mechanisms including HIF-1A.

During first trimester pregnancy, trophoblast cells invade from the placenta into the maternal decidua where they anchor the placenta and remodel luminal structures like spiral arteries. This process depends on proteases secreted by invading trophoblasts, which degrade extracellular matrix (ECM). We here aimed to identify proteases particularly important for trophoblast invasion. We generated a list of proteases capable of degrading decidual ECM and trophoblast integrins using MEROPS database and compared expression of these proteases between primary trophoblasts isolated from first trimester placenta (FT, n = 3), representing an invasive phenotype, vs trophoblasts isolated from term pregnancy (TT, n = 3), representing a non-invasive trophoblast phenotype. Matrix metalloproteinase 12 (MMP12) revealed highest expression levels in FT, with absent expression in TT. In situ hybridisation and immunofluorescence localised MMP12 specifically to extravillous trophoblasts (evCT) whilst Ki67 co-staining revealed that proliferating trophoblasts of the cell columns were almost negative for MMP12. Quantification revealed a decline in MMP12 positive evCT at the end of first trimester, when oxygen levels start rising. MMP12 promoter analysis identified potential binding sites for hypoxia-inducible factor (HIF-1) and other oxygen-sensitive transcription factors. Moreover, MMP12 protein was increased by low oxygen in FT in vitro and by addition of a HIF-1α activator. Collectively, MMP12 is a highly expressed protease specific for invasive evCT during the first trimester. MMP12 down regulation by increasing oxygen concentration enables temporal expression control of MMP12 and involves several mechanisms including HIF-1α. These findings suggest MMP12 involved in trophoblast invasion during the first trimester.

Cyanoacrylate Burn Injuries: Two Unusual Cases and a Review of the Literature.

The authors present 2 cases of cyanoacrylate glue ("Super Glue") burns, with a review of the literature and a discussion on the mechanism of action. The authors found all reported cases were with domestic - not medical-grade - cyanoacrylate glue in the presence of cotton fabric. Often erroneously designated as chemical burns, they are thermal burns caused by an intensive exothermic reaction. Cotton acts as a highly potent catalyst, speeding up the polymerization reaction leading to high-peak temperatures capable of causing burns and spontaneous ignition of the fabric. The authors identify factors that explain the different risk profiles of domestic and medical cyanoacrylate glues and could be addressed to improve safety with nonmedical applications.