**6. Conclusions**

To our knowledge, we were the first to examine Rarres1 localization in the rodent placenta. Also, Rarres1 and 2 expressions have not been studied in the above rodent models.

Rarres1/2 findings in both animal models did not resemble placental alterations of RARRES1/2 observed by us in human PE or PE/IUGR. These results might indicate species-specific di fferences in placental regulation and compartmentation. The fact that others observed reduced placental Rarres2 expression following more profound maternal food restriction suggests metabolic functions of the peptide beyond its potential tumor-suppressor role that need further investigation. Furthermore, the clarification of a potential feto-maternal crosstalk via adipocytokine Rarres2 and its possible role in the regulation of immunologic and inflammatory processes at the placental interface requires further functional studies. Moreover, the role of IL-11 in the placental pathophysiology of eNOS−/− mice remains to be determined.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/1422-0067/21/1/242/s1, Figure S1: Specificity testing of the antibody to RARRES1, Figure S2: Specificity testing of the antibody to RARRES2.

**Author Contributions:** Conceptualization, Validation and Project Administration by F.B.F. and A.H.; Methodology and Visualization by M.S., R.W., H.H., and N.C.; Investigation, Data Acquisition and Analysis, Software and Preparation of Original Draft by A.M.; Reviewing and Editing by C.M.-C.; Supervision and Resources by A.H. Revision by F.B.F., A.H., and A.M. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Deutsche Forschungsgemeinschaft and Friedrich-Alexander-University Erlangen-Nürnberg (FAU) within the funding program Open Access Publishing.

**Acknowledgments:** Data acquisition was performed by Alexander F. C. Mocker in fulfillment of the requirements for obtaining the degree "med." at the Friedrich-Alexander University of Erlangen-Nürnberg, Department of Pediatrics and Adolescent Medicine, Germany. We thank M. Kupraszewicz-Hutzler for supervising the immunohistochemistry.

**Conflicts of Interest:** The authors declare no conflict of interest. Funding by DFG had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.
