Fungi Journal of Article Evaluation of Sex Differences in Murine Diabetic Ketoacidosis and Neutropenic Models of Invasive Mucormycosis Teclegiorgis Gebremariam 1 , Sondus Alkhazraji 1 , Abdullah Alqarihi 1 , Nathan P. Wiederhold 2 , Laura K. Najvar 2,3 , Thomas F. Patterson 2,3 , Scott G. Filler 1,4 and Ashraf S. Ibrahim 1,4, *   Citation: Gebremariam, T.; Alkhazraji, S.; Alqarihi, A.; Wiederhold, N.P.; Najvar, L.K.; Patterson, T.F.; Filler, S.G.; Ibrahim, A.S. Evaluation of Sex Differences in Murine Diabetic Ketoacidosis and Neutropenic Models of Invasive Mucormycosis. J. Fungi 2021, 7, 313. https://doi.org/10.3390/jof7040313 Academic Editor: Michaela Lackner Received: 8 April 2021 Accepted: 16 April 2021 Published: 18 April 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 The Division of Infectious Diseases, The Lundquist Institute for Biomedical Innovation at Harbor-University of California at Los Angeles (UCLA) Medical Center, Torrance, CA 90502, USA; tghbremariam@lundquist.org (T.G.); salkhazraji@lundquist.org (S.A.); aalqarihi@lundquist.org (A.A.); sfiller@lundquist.org (S.G.F.) 2 University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; wiederholdn@uthscsa.edu (N.P.W.); NAJVAR@uthscsa.edu (L.K.N.); patterson@uthscsa.edu (T.F.P.) 3 South Texas Veterans Health Care System, San Antonio, TX 78229, USA 4 David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA * Correspondence: ibrahim@lundquist.org; Tel.: +1-310-222-6424 Abstract: There is increased concern that the quality, generalizability and reproducibility of biomed- ical research can be influenced by the sex of animals used. We studied the differences between male and female mice in response to invasive pulmonary mucormycosis including susceptibility to infection, host immune reaction and responses to antifungal therapy. We used diabetic ketoacidotic (DKA) or neutropenic mice infected with either Rhizopus delemar or Mucor circinelloides. The only difference detected was that when DKA mice were infected with M. circinelloides, female mice were more resistant to infection than male mice (median survival time of 5 vs. 2 days for female and male mice, respectively). However, a 100% lethality was detected among infected animals of both sexes. Treatment with either liposomal amphotericin B (L-AMB) or posaconazole (POSA) protected mice from infection and eliminated the difference seen between infected but untreated female and male mice. Treatment with L-AMB consistently outperformed POSA in prolonging survival and reducing tissue fungal burden of DKA and neutropenic mice infected with R. delemar or M. circinelloides, in both mouse sexes. While little difference was detected in cytokine levels among both sexes, mucormycosis infection in the DKA mouse model induced more inflammatory cytokines/chemokines involved in neutrophil (CXCL1) and macrophage (CXCL2) recruitment vs. uninfected mice. As expected, this inflammatory response was reduced in the neutropenic mouse model. Our studies show that there are few differences between female and male DKA or neutropenic mice infected with mucormycosis with no effect on the outcome of treatment or host immune response. Keywords: Rhizopus; Mucor; mucormycosis; murine; sex 1. Introduction There is a growing concern in the scientific community and lay public about the reproducibility of biomedical research. Study design elements that are critical to the reproducibility of results include, but are not limited to blinding, randomization and sample-size calculations [1,2]. Pre-clinical research with animal models may be difficult to reproduce, due to differences in the strain of animals that is used, laboratories and laboratory environments and subtle changes in protocols that may not be effectively communicated in publications [1,2]. In addition, there is increased recognition that the quality, generalizability and reproducibility of biomedical research can be influenced by sex of the experimental animal, and that the over-reliance on a single sex of animals in pre-clinical research may obscure key sex differences that could guide clinical trials [1]. Thus, the National Institutes of Health (NIH) now recognizes that the failure to account for J. Fungi 2021, 7, 313. https://doi.org/10.3390/jof7040313 https://www.mdpi.com/journal/jof