Breakthrough candidemia with hematological disease: Results from a single-center retrospective study in Japan, 2009-2020.

Breakthrough candidemia (BrC) is a significant problem in immunocompromised patients, particularly those with hematological disorders. To assess the characteristics of BrC in patients with hematologic disease treated with novel antifungal agents, we collected clinical and microbiological information on said patients from 2009 to 2020 in our institution. Forty cases were identified, of which 29 (72.5%) received hematopoietic stem cell transplant (HSCT)-related therapy. At BrC onset, the most administered class of antifungal agents were echinocandins, administered to 70% of patients. Candida guilliermondii complex was the most frequently isolated species (32.5%), followed by C. parapsilosis (30%). These two isolates were echinocandin-susceptible in vitro but had naturally occurring FKS gene polymorphisms that reduced echinocandin susceptibility. Frequent isolation of these echinocandin-reduced-susceptible strains in BrC may be associated with the widespread use of echinocandins. In this study, the 30-day crude mortality rate in the group receiving HSCT-related therapy was significantly higher than in the group not receiving it (55.2% versus 18.2%, P = .0297). Most patients affected by C. guilliermondii complex BrC (92.3%) received HSCT-related therapy and had a 30-day mortality rate of 53.8%; despite treatment administration, 3 of 13 patients had persistent candidemia. Based on our results, C. guilliermondii complex BrC is a potentially fatal condition in patients receiving HSCT-related therapy with echinocandin administration.

This retrospective study was conducted at a Japanese center specializing in hematopoietic stem cell transplants and found that the rare pathogen Candida guilliermondii complex was the most common cause of breakthrough candidemia, with high mortality rate, which is a concern for transplant patients.

A host-directed macrocyclic peptide therapeutic for MDR gram negative bacterial infections.

The emergence of infections by carbapenem resistant Enterobacteriaceae (CRE) pathogens has created an urgent public health threat, as carbapenems are among the drugs of last resort for infections caused by a growing fraction of multi-drug resistant (MDR) bacteria. There is global consensus that new preventive and therapeutic strategies are urgently needed to combat the growing problem of MDR bacterial infections. Here, we report on the efficacy of a novel macrocyclic peptide, minimized theta-defensin (MTD)-12813 in CRE sepsis. MTD12813 is a theta-defensin inspired cyclic peptide that is highly effective against CRE pathogens K. pneumoniae and E. coli in vivo. In mouse septicemia models, single dose administration of MTD12813 significantly enhanced survival by promoting rapid host-mediated bacterial clearance and by modulating pathologic cytokine responses, restoring immune homeostasis, and preventing lethal septic shock. The peptide lacks direct antibacterial activity in the presence of mouse serum or in peritoneal fluid, further evidence for its indirect antibacterial mode of action. MTD12813 is highly stable in biological matrices, resistant to bacterial proteases, and nontoxic to mice at dose levels 100 times the therapeutic dose level, properties which support further development of the peptide as a first in class anti-infective therapeutic.

p300 Serine 89: A Critical Signaling Integrator and Its Effects on Intestinal Homeostasis and Repair.

Differential usage of Kat3 coactivators, CBP and p300, by ß-catenin is a fundamental regulatory mechanism in stem cell maintenance and initiation of differentiation and repair. Based upon our earlier pharmacologic studies, p300 serine 89 (S89) is critical for controlling differential coactivator usage by ß-catenin via post-translational phosphorylation in stem/progenitor populations, and appears to be a target for a number of kinase cascades. To further investigate mechanisms of signal integration effected by this domain, we generated p300 S89A knock-in mice. We show that S89A mice are extremely sensitive to intestinal insult resulting in colitis, which is known to significantly increase the risk of developing colorectal cancer. We demonstrate cell intrinsic differences, and microbiome compositional differences and differential immune responses, in intestine of S89A versus wild type mice. Genomic and proteomic analyses reveal pathway differences, including lipid metabolism, oxidative stress response, mitochondrial function and oxidative phosphorylation. The diverse effects on fundamental processes including epithelial differentiation, metabolism, immune response and microbiome colonization, all brought about by a single amino acid modification S89A, highlights the critical role of this region in p300 as a signaling nexus and the rationale for conservation of this residue and surrounding region for hundreds of million years of vertebrate evolution.

Inhibition of Stearoyl-CoA Desaturase Induces the Unfolded Protein Response in Pancreatic Tumors and Suppresses Their Growth.

OBJECTIVE: Pancreatic ductal adenocarcinoma is the fourth-leading cause of cancer death in the United States, and there is an urgent need for effective therapies. Stearoyl-CoA desaturase (SCD) is an enzyme localized in the endoplasmic reticulum and generates monounsaturated fatty acid from saturated fatty acid. In this study, we examined the role of SCD in pancreatic cancer. METHODS: We isolated epithelial cell adhesion molecule-positive pancreatic tumors from the Pdx1Cre;LSL-KrasG12D mouse and formed organoids in Matrigel. Using a SCD inhibitor, A939572, we tested its effects on growth and cell death in tumor organoids, tumors developed in the Pdx1Cre;LSL-KrasG12D mouse, and a human pancreatic ductal adenocarcinoma cell line, PANC-1. RESULTS: A939572 treatment rapidly induced degeneration of mouse tumor organoids and activated the unfolded protein response (UPR). Cotreatment of oleic acid, but not stearic acid, reduced the UPR in the organoids and rescued the inhibitory effect of the SCD inhibitor on their growth. Administration of A939572 to Pdx1Cre;LSL-KrasG12D mice caused cell death in early pancreatic tumors, but not in acini or islets. The SCD inhibitor induced the UPR in PANC-1 and suppressed their growth but did not induce cell death. CONCLUSIONS: The inhibition of the SCD enzyme causes an UPR and cell death in early pancreatic tumors.

Essential role of IFN-γ in T cell-associated intestinal inflammation.

Paneth cells contribute to small intestinal homeostasis by secreting antimicrobial peptides and constituting the intestinal stem cell (ISC) niche. Certain T cell-mediated enteropathies are characterized by extensive Paneth cell depletion coincident with mucosal destruction and dysbiosis. In this study, mechanisms of intestinal crypt injury have been investigated by characterizing responses of mouse intestinal organoids (enteroids) in coculture with mouse T lymphocytes. Activated T cells induced enteroid damage, reduced Paneth cell and Lgr5+ ISC mRNA levels, and induced Paneth cell death through a caspase-3/7-dependent mechanism. IFN-γ mediated these effects, because IFN-γ receptor-null enteroids were unaffected by activated T cells. In mice, administration of IFN-γ induced enteropathy with crypt hyperplasia, villus shortening, Paneth cell depletion, and modified ISC marker expression. IFN-γ exacerbated radiation enteritis, which was ameliorated by treatment with a selective JAK1/2 inhibitor. Thus, IFN-γ induced Paneth cell death and impaired regeneration of small intestinal epithelium in vivo, suggesting that IFN-γ may be a useful target for treating defective mucosal regeneration in enteric inflammation.

Entamoeba histolytica Alters Ileal Paneth Cell Functions in Intact and Muc2 Mucin Deficiency.

Enteric α-defensins, termed cryptdins (Crps) in mice, and lysozymes secreted by Paneth cells contribute to innate host defense in the ileum. Antimicrobial factors, including lysozymes and ß-defensins, are often embedded in luminal glycosylated colonic Muc2 mucin secreted by goblet cells that form the protective mucus layer critical for gut homeostasis and pathogen invasion. In this study, we investigated ileal innate immunity against Entamoeba histolytica, the causative agent of intestinal amebiasis, by inoculating parasites in closed ileal loops in Muc2+/+ and Muc2-/- littermates and quantifying Paneth cell localization (lysozyme expression) and function (Crp secretion). Relative to Muc2+/+ littermates, Muc2-/- littermates showed a disorganized mislocalization of Paneth cells that was diffusely distributed, with elevated lysozyme secretion in the crypts and on villi in response to E. histolytica Inhibition of E. histolytica Gal/GalNAc lectin (Gal-lectin) binding with exogenous galactose and Entamoeba histolytica cysteine proteinase 5 (EhCP5)-negative E. histolytica had no effect on parasite-induced erratic Paneth cell lysozyme synthesis. Although the basal ileal expression of Crp genes was unaffected in Muc2-/- mice in response to E. histolytica, there was a robust release of proinflammatory cytokines and Crp peptide secretions in luminal exudates that was also present in the colon. Interestingly, E. histolytica-secreted cysteine proteinases cleaved the proregion of Crp4 but not the active form. These findings define Muc2 mucin as an essential component of ileal barrier function that regulates the localization and function of Paneth cells critical for host defense against microbes.

Reciprocal expression of enteric antimicrobial proteins in intestinal graft-versus-host disease.

We recently demonstrated that expression of α-defensins, the major antimicrobial peptides produced by Paneth cells, was severely suppressed in mice with graft-versus-host disease (GVHD). In this study, we found that antibacterial lectin, regenerating islet-derived IIIγ (RegIIIγ) was upregulated in villous enterocytes, thus demonstrating the reciprocal control of enteric antimicrobial proteins in GVHD. Upregulation of RegIIIγ was mediated by a mechanism independent upon radiation-induced intestinal tract damage. MyD88-mediated signaling in intestinal epithelium was required for RegIIIγ upregulation in GVHD and antibiotic therapy downregulated RegIIIγ expression. These results suggest that MyD88-mediated sensing of the intestinal microbes disregulated in GVHD induces RegIIIγ upregulation in GVHD and argue a role for RegIIIγ in the pathogenesis of GVHD.

Graft-versus-host disease disrupts intestinal microbial ecology by inhibiting Paneth cell production of α-defensins.

Allogeneic hematopoietic stem cell transplantation (SCT) is a curative therapy for various hematologic disorders. Graft-versus-host disease (GVHD) and infections are the major complications of SCT, and their close relationship has been suggested. In this study, we evaluated a link between 2 complications in mouse models. The intestinal microbial communities are actively regulated by Paneth cells through their secretion of antimicrobial peptides, α-defensins. We discovered that Paneth cells are targeted by GVHD, resulting in marked reduction in the expression of α-defensins, which selectively kill noncommensals, while preserving commensals. Molecular profiling of intestinal microbial communities showed loss of physiologic diversity among the microflora and the overwhelming expansion of otherwise rare bacteria Escherichia coli, which caused septicemia. These changes occurred only in mice with GVHD, independently on conditioning-induced intestinal injury, and there was a significant correlation between alteration in the intestinal microbiota and GVHD severity. Oral administration of polymyxin B inhibited outgrowth of E coli and ameliorated GVHD. These results reveal the novel mechanism responsible for shift in the gut flora from commensals toward the widespread prevalence of pathogens and the previously unrecognized association between GVHD and infection after allogeneic SCT.

[Hematological unit invasive aspergillosis epidemiology].

Invasive aspergillosis (IA) is a major cause of morbidity and mortality among the immunocompromised, especially those undergoing hematopoietic stem cell transplantation. With spore inhalation the usual infection route, such subjects must be protected from environmental spore contamination, necessitating measures such as high-efficiency particulate air (HEPA) filtration. In April 2006, we implemented a new transplantation unit with HEPA filtration. We retrospectively evaluated its efficacy for hospitalized transplantation unit subjects whose sera were tested for aspergillus galactomannan antigen between April 2004 and March 2007. Subjects numbered 265 (973 samples) categorized as definite, probable, or possible. The earliest IA onset date was when symptoms, positive radiological findings, or positive galactomannan antigen tests occurred, based on revised European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and National Institute of Allergy and Infectious Diseases Mycoses Study Group (EORTC/MSG) definitions. We classified cases when IA occurred over 10 days after admission as hospital-acquired. No such cases were detected after November 2005 and IA incidence decreased significantly after the new unit began being used. Results suggest that the new unit and HEPA filtration helped eliminate nosocomial IA.

[A case of relapsed ischemic colitis with colon cast-like stripped mucosa].

An 82-year-old woman who had 5 relapses of ischemic colitis was admitted with sudden lower abdominal pain. Colonoscopic examination performed on the 2nd day revealed colon cast-like stripped colonic mucosa in the lower portion of the descending colon. She was treated conservatively. After 2 weeks, ischemic colitis healed, with slight residual stenosis. Most reports of colon cast indicated that colon cast was caused by abdominal aneurysm, operation, or external wound. The only predisposing conditions in this case were arteriosclerosis of abdominal aorta and chronic constipation. Arteriosclerosis and chronic constipation might be the important risk factors of ischemic colitis with colon cast and relapsing of ischemic colitis.