A Novel Cryptococcal Meningitis Therapy: The Combination of Amphotericin B and Posaconazole Promotes the Distribution of Amphotericin B in the Brain Tissue.

Ming Yang,Mingjie Yu,Qian Yuan,Fengjun Sun,Wei Feng,Peiyuan Xia,Bo Yang,Lin Cheng,Qing Dai,Lei Zhang

doi:10.1155/2020/8878158

Abstract

The deficient brain tissue distribution of amphotericin B (AMPB) seriously restricts its treatment for the clinical efficacy of cryptococcus neoformans meningitis (CNM). We strive to develop a tactic to increase its concentration in brain tissue. We aimed to investigate whether the combination of AMPB and posaconazole (POS) could be more effective in the treatment of CNM and to elucidate its potential mechanisms. HPLC analysis was used to analyze the concentration of AMPB in mouse serum, brain tissue, and BCECs cells. Schrodinger molecular docking, in vitro plasma balance dialysis, and ultrafiltration analysis were performed to evaluate the combinative effect of AMPB and POS with serum albumin and POS on AMPB plasma protein binding. H&E staining and colonization culture experiment of CN were employed to assess the effect of POS on the efficacy of AMPB. POS + AMPB significantly reduced the concentration of plasma total AMPB and increased its concentration in the brain tissue. However, the P-gp inhibitor zosuquidar, BCRP inhibitor Ko143, and a common inhibitor of both, elacridar, had no significant effect on its concentration. Molecular docking, balance dialysis, and ultrafiltration analysis showed that AMPB and POS had potential binding properties to serum albumin. Meanwhile, 4 and 8 μg/mL POS could significantly increase the concentration of free AMPB in plasma. POS and three inhibitors all had no significant effect on the uptake of AMPB by BCECs, but serum albumin had. The therapeutic effect of CNM in mice was confirmed that AMPB and AMPB+POS could restrain the infiltration of neutrophils and lymphocytes in cortical neurons and improve the bleeding and markedly inhibit the proliferation of CN. Collectively, we propose that POS competitively binds to the plasma protein sites of AMPB, thereby increasing its level in the brain tissue. Meanwhile, POS could enhance the efficacy of AMPB in the treatment of CNM, which may be independent of P-gp and BCRP proteins.

Highlights

As a kind of saprophyte bacteria, cryptococcus neoformans, known as torula histolytica, is widely existing in natural soil, pigeon, milk, and fruit
In order to determine whether POS can promote the distribution of amphotericin B (AMPB) in the brain tissue, the contents of AMPB in the plasma and brain tissue of normal healthy KM mice were detected by high-performance liquid chromatography (HPLC) after administering AMPB and AMPB+POS
The results showed that compared with the AMPB group, AMPB+POS can significantly increase the brain tissue concentrations of AMPB (Figures 1(a) and 1(c) p < 0:01), while decrease the plasma drug concentration (Figures 1(a) and 1(d) p < 0:01), increasing the AMPB brain tissue/plasma drug ratio (Figure 1(e) p < 0:01), which may partly associate with POS competitive combined with plasma proteins

Summary

Introduction

As a kind of saprophyte bacteria, cryptococcus neoformans, known as torula histolytica, is widely existing in natural soil, pigeon, milk, and fruit. It is an exogenous infection commonly by opportunistic pathogen [1]. When the body’s immune function declines, such as infection with human immunodeficiency virus or lymphoma patients, cryptococcus neoformans can invade the central nervous system (CNS), leading to a fungal infection in CNS, manifested as fungal meningitis, encephalitis, and granuloma of the brain, namely, cryptococcus neogenes meningitis (CNM) [3]. For patients with lower immunity, the symptoms are acute, headache, nausea, and vomiting [4]

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