Antifungal efficacy of isavuconazole and liposomal amphotericin B in a rabbit model of Exserohilum rostratum meningoencephalitis: A preclinical paradigm for management of CNS phaeohyphomycosis

Effect of Monocerin, a Fungal Secondary Metabolite, on Endothelial Cells

This study reports the isolation and identification of the endophytic fungus Exserohilum rostratum through molecular and morphological analysis using optical and transmission electron microscopy (TEM), as well as the procurement of its secondary metabolite monocerin, an isocoumarin derivative. Considering the previously observed biological activities of monocerin, this study was performed on human umbilical vein endothelial cells (HUVECs) that are widely used as an in vitro model for several different purposes. Important parameters, such as cell viability, senescence-associated β-galactosidase, cellular proliferation by using 5(6)-carboxyfluorescein diacetate N-succinimidyl ester (CFSE), apoptosis analysis with annexin, cellular morphology through scanning electron microscopy (SEM), and laser confocal analysis were evaluated after exposing the cells to monocerin. After 24 h of exposure to monocerin at 1.25 mM, there was more than 80% of cell viability and a low percentage of cells in the early and late apoptosis and necrosis. Monocerin increased cell proliferation and did not induce cell senescence. Morphological analysis showed cellular integrity. The study demonstrates aspects of the mechanism of action of monocerin on endothelial cell proliferation, suggesting the possibility of its pharmaceutical application, such as in regenerative medicine.

Invasive Fungal Rhinosinusitis Due to Co-infection with Mucormycosis and Exserohilum rostratum in a Patient with Acute Lymphoblastic Leukemia

Invasive fungal infections remain an important cause of complication and morbidity in the management of acute leukemias. Here we report the case of a 27-year-old patient from French Polynesia who was diagnosed with Philadelphia chromosome-negative B-cell acute lymphoblastic leukemia. After induction chemotherapy, she developed rhinosinusitis with extensive bone lysis. The context and clinical presentation quickly made us suspect an invasive mucormycosis infection. However, a multidisciplinary investigation including mass spectrometry techniques also revealed the presence of Exserohilum rostratum, a pathogen member of the genus Exserohilum that is ubiquitous in tropical and subtropical regions but rarely implicated in invasive sinusitis. Antifungal treatment combined with an early surgical approach resulted in a favorable clinical response.