scholarly journals Combination therapy with amphotericin B and fluconazole against invasive candidiasis in neutropenic-mouse and infective-endocarditis rabbit models.

1997 ◽  
Vol 41 (6) ◽  
pp. 1345-1348 ◽  
Author(s):  
H Sanati ◽  
C F Ramos ◽  
A S Bayer ◽  
M A Ghannoum
Keyword(s):  
Infective Endocarditis ◽  
Combination Therapy ◽  
Mouse Model ◽  
Amphotericin B ◽  
Antifungal Agents ◽  
Combined Therapy ◽  
Rabbit Model ◽  
Model Treatment ◽  
The Brain

Although there are an increasing number of new antifungal agents available, the morbidity and mortality due to invasive mycoses remain high. The high rates of polyene toxicities and the development of azole resistance have raised the issue of using antifungal agents of these classes in combination, despite theoretical concerns regarding antagonism between such agents. This study was designed to evaluate the in vivo efficacy of combined therapy with amphotericin B and fluconazole against Candida albicans. Two distinct animal models were used in this study: a neutropenic-mouse model of hematogenously disseminated candidiasis and the infective-endocarditis rabbit model. Treatment efficacy was assessed by determining reductions in mortality as well as decreases in tissue fungal densities. In the neutropenic-mouse model, amphotericin B, as well as combination therapy, significantly prolonged survival compared to untreated controls (P < 10(-5) and P = 0.001, respectively). The fungal densities in the kidneys of neutropenic mice were significantly reduced with either amphotericin B monotherapy or amphotericin B-fluconazole combined therapy compared to those of controls (P < 10(-6)). Fluconazole monotherapy also reduced fungal densities in the kidneys; however, this decrease was not statistically significant (P = 0.17). In contrast, treatment with either fluconazole alone or combined with amphotericin B (but not amphotericin B monotherapy) significantly decreased fungal densities in the brain (P = 0.025). In the rabbit endocarditis model, amphotericin B monotherapy or combined therapy significantly decreased fungal densities in cardiac vegetations (P < 0.01 versus the controls). Although no significant antagonism was seen when fluconazole was given in combination with amphotericin B, combination therapy did not augment the antifungal activity of amphotericin B.

scholarly journals A novel antioxidant ergothioneine PET radioligand for in vivo imaging applications

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
William J. Behof ◽  
Clayton A. Whitmore ◽  
Justin R. Haynes ◽  
Adam J. Rosenberg ◽  
Mohammed N. Tantawy ◽  
...  
Keyword(s):  
Amino Acid ◽  
Mouse Model ◽  
Peripheral Tissues ◽  
Molar Activity ◽  
Model Of Alzheimer’S Disease ◽  
Specific Retention ◽  
5Xfad Mice ◽  
The Brain

AbstractErgothioneine (ERGO) is a rare amino acid mostly found in fungi, including mushrooms, with recognized antioxidant activity to protect tissues from damage by reactive oxygen species (ROS) components. Prior to this publication, the biodistribution of ERGO has been performed solely in vitro using extracted tissues. The aim of this study was to develop a feasible chemistry for the synthesis of an ERGO PET radioligand, [11C]ERGO, to facilitate in vivo study. The radioligand probe was synthesized with identical structure to ERGO by employing an orthogonal protection/deprotection approach. [11C]methylation of the precursor was performed via [11C]CH3OTf to provide [11C]ERGO radioligand. The [11C]ERGO was isolated by RP-HPLC with a molar activity of 690 TBq/mmol. To demonstrate the biodistribution of the radioligand, we administered approximately 37 MBq/0.1 mL in 5XFAD mice, a mouse model of Alzheimer’s disease via the tail vein. The distribution of ERGO in the brain was monitored using 90-min dynamic PET scans. The delivery and specific retention of [11C]ERGO in an LPS-mediated neuroinflammation mouse model was also demonstrated. For the pharmacokinetic study, the concentration of the compound in the serum started to decrease 10 min after injection while starting to distribute in other peripheral tissues. In particular, a significant amount of the compound was found in the eyes and small intestine. The radioligand was also distributed in several regions of the brain of 5XFAD mice, and the signal remained strong 30 min post-injection. This is the first time the biodistribution of this antioxidant and rare amino acid has been demonstrated in a preclinical mouse model in a highly sensitive and non-invasive manner.

scholarly journals Impact of the Order of Initiation of Fluconazole and Amphotericin B in Sequential or Combination Therapy on Killing of Candida albicans In Vitro and in a Rabbit Model of Endocarditis and Pyelonephritis

2001 ◽  
Vol 45 (2) ◽  
pp. 485-494 ◽  
Author(s):  
Arnold Louie ◽  
Pamela Kaw ◽  
Partha Banerjee ◽  
Weiguo Liu ◽  
George Chen ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Amphotericin B ◽  
Induced Resistance ◽  
Rabbit Model ◽  
In Vivo Studies ◽  
Infection Model ◽  
Simultaneous Exposure ◽  
The Impact

ABSTRACT In vitro time-kill studies and a rabbit model of endocarditis and pyelonephritis were used to define the impact that the order of exposure of Candida albicans to fluconazole (FLC) and amphotericin B (AMB), as sequential and combination therapies, had on the susceptibility of C. albicans to AMB and on the outcome. The contribution of FLC-induced resistance to AMB for C. albicans also was assessed. In vitro, AMB monotherapy rapidly killed each of four C. albicans strains; FLC alone was fungistatic. Preincubation of these fungi with FLC for 18 h prior to exposure to AMB decreased their susceptibilities to AMB for 8 to >40 h. Induced resistance to AMB was transient, but the duration of resistance increased with the length of FLC preincubation. Yeast sequentially incubated with FLC followed by AMB plus FLC (FLC→AMB+FLC) showed fungistatic growth kinetics similar to that of fungi that were exposed to FLC alone. This antagonistic effect persisted for at least 24 h. Simultaneous exposure of C. albicans to AMB and FLC [AMB+FLC(simult)] demonstrated activity similar to that with AMB alone for AMB concentrations of ≥1 μg/ml; antagonism was seen using an AMB concentration of 0.5 μg/ml. The in vitro findings accurately predicted outcomes in our rabbit infection model. In vivo, AMB monotherapy and treatment with AMB for 24 h followed by AMB plus FLC (AMB→AMB+FLC) rapidly sterilized kidneys and cardiac vegetations. AMB+FLC(simult) and FLC→AMB treatments were slower in clearing fungi from infected tissues. FLC monotherapy and FLC→AMB+FLC were both fungistatic and were the least active regimens. No adverse interaction was observed between AMB and FLC for the AMB→FLC regimen. However, FLC→AMB treatment was slower than AMB alone in clearing fungi from tissues. Thus, our in vitro and in vivo studies both demonstrate that preexposure of C. albicans to FLC reduces fungal susceptibility to AMB. The length of FLC preexposure and whether AMB is subsequently used alone or in combination with FLC determine the duration of induced resistance to AMB.

Anlotinib enhanced penpulimab efficacy through remodeling of tumor vascular architecture and immune microenvironment in hPD-L1/hPD-1 humanized mouse model.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. 2581-2581
Author(s):  
Yunlong Shan ◽  
Chongjin Zhong ◽  
Qi Ni ◽  
Mengying Zhang ◽  
Guangji Wang ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Mouse Model ◽  
Immune Cells ◽  
Immune Checkpoint ◽  
Tumor Volume ◽  
Combined Therapy ◽  
Control Group ◽  
Tyrosine Kinase Receptor ◽  
Humanized Mouse ◽  
Humanized Mouse Model

2581 Background: Even though immune checkpoint inhibitor (ICI) such as anti-PD-1 mAb has emerged as effective treatment for tumor regression, the response rate of ICI monotherapy in solid tumor is low. Many studies have demonstrated that the efficacy of combination therapy of ICI and anti-angiogenesis was superior to monotherapy. Penpulimab (AK105), a humanized IgG1 mAb that blocks PD-1 binding to PD-L1, engineered to eliminate FcγR binding and ADCC/ADCP completely. Here, we explore a new combined therapy of penpulimab and anlotinib, an oral multi-targeted tyrosine kinase receptor inhibitor. Methods: MC38-hPD-L1 tumor-bearing B-hPD-1 humanized mouse model were conducted to investigate the effects of anlotinib (1 mg/kg, every day, p.o) or penpulimab (5 mg/kg, twice a week, i.p) alone or in combination. Immunofluorescence was applied to elucidate tumor vessel normalization. In vivo imaging was conducted to detect the distribution of AF647-labelled penpulimab after anlotinib treatment. Flow cytometry and other techniques were performed to investigate intratumoral immune cells. Results: After 3-week treatment, immunotherapeutic administration of anlotinib or penpulimab showed moderate inhibition of tumor growth (tumor volume: 66.5% and 58.4% of control group, respectively), while combined treatment of anlotinib with penpulimab significantly decreased tumor volume to 36.5% of control group. Tissue pathological and blood biochemical results showed no significant toxic and side effects. Immunohistochemistry revealed that anlotinib induced tumor vascular normalization, indicated by decreased CD31+ area, increased α-SMA around tumor vessels and reduced GLUT1+ area. Furthermore, anlotinib markedly enhanced the delivery of AF647-penpulimab into tumors. Combining anlotinib with penpulimab also promoted infiltration and activity of anti-tumoral immune cells by reducing the level of immune checkpoint TIM3 and increasing the IFNγ secretion from T cells. Conclusions: Our work provides a strong scientific rationale for the combination therapy of anlotinib and penpulimab to improve tumor microenvironment and immunotherapy, which highlights the clinical potential for this new combined therapy.

scholarly journals The SMAC mimetic LCL-161 selectively targets JAK2V617F mutant cells

2020 ◽  
Vol 9 (1) ◽  
Author(s):  
Brianna M. Craver ◽  
Thanh Kim Nguyen ◽  
Jenny Nguyen ◽  
Hellen Nguyen ◽  
Christy Huynh ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Mouse Model ◽  
Characteristic Feature ◽  
Kinase Activity ◽  
Differential Sensitivity ◽  
Smac Mimetics ◽  
Smac Mimetic ◽  
Mutant Cells

Abstract Background Evasion from programmed cell death is a hallmark of cancer and can be achieved in cancer cells by overexpression of inhibitor of apoptosis proteins (IAPs). Second mitochondria-derived activator of caspases (SMAC) directly bind to IAPs and promote apoptosis; thus, SMAC mimetics have been investigated in a variety of cancer types. particularly in diseases with high inflammation and NFĸB activation. Given that elevated TNFα levels and NFĸB activation is a characteristic feature of myeloproliferative neoplasms (MPN), we investigated the effect of the SMAC mimetic LCL-161 on MPN cell survival in vitro and disease development in vivo. Methods To investigate the effect of the SMAC mimetic LCL-161 in vitro, we utilized murine and human cell lines to perform cell viability assays as well as primary bone marrow from mice or humans with JAK2V617F–driven MPN to interrogate myeloid colony formation. To elucidate the effect of the SMAC mimetic LCL-161 in vivo, we treated a JAK2V617F–driven mouse model of MPN with LCL-161 then assessed blood counts, splenomegaly, and myelofibrosis. Results We found that JAK2V617F-mutated cells are hypersensitive to the SMAC mimetic LCL-161 in the absence of exogenous TNFα. JAK2 kinase activity and NFĸB activation is required for JAK2V617F-mediated sensitivity to LCL-161, as JAK or NFĸB inhibitors diminished the differential sensitivity of JAK2V617F mutant cells to IAP inhibition. Finally, LCL-161 reduces splenomegaly and may reduce fibrosis in a mouse model of JAK2V617F-driven MPN. Conclusion LCL-161 may be therapeutically useful in MPN, in particular when exogenous TNFα signaling is blocked. NFĸB activation is a characteristic feature of JAK2V617F mutant cells and this sensitizes them to SMAC mimetic induced killing even in the absence of TNFα. However, when exogenous TNFα is added, NFĸB is activated in both mutant and wild-type cells, abolishing the differential sensitivity. Moreover, JAK kinase activity is required for the differential sensitivity of JAK2V617F mutant cells, suggesting that the addition of JAK2 inhibitors to SMAC mimetics would detract from the ability of SMAC mimetics to selectively target JAK2V617F mutant cells. Instead, combination therapy with other agents that reduce inflammatory cytokines but preserve JAK2 signaling in mutant cells may be a more beneficial combination therapy in MPN.

scholarly journals Antibodies to a Surface-Exposed, N-terminal Domain of Aggregation Substance Are Not Protective in the Rabbit Model of Enterococcus faecalis Infective Endocarditis

2001 ◽  
Vol 69 (5) ◽  
pp. 3305-3314 ◽  
Author(s):  
John K. McCormick ◽  
Helmut Hirt ◽  
Christopher M. Waters ◽  
Timothy J. Tripp ◽  
Gary M. Dunny ◽  
...  
Keyword(s):  
Infective Endocarditis ◽  
Enterococcus Faecalis ◽  
Rabbit Model ◽  
Surface Protein ◽  
Conjugative Plasmid ◽  
Aggregation Substance ◽  
Exposed Region ◽  
Correct Sequence

ABSTRACT The aggregation substance (AS) surface protein fromEnterococcus faecalis has been implicated as an important virulence factor for the development of infective endocarditis. To evaluate the role of antibodies specific for Asc10 (the AS protein from the conjugative plasmid pCF10) in protective immunity to infective endocarditis, an N-terminal region of Asc10 lacking the signal peptide and predicted to be surface exposed (amino acids 44 to 331; AS44–331) was cloned with a C-terminal histidine tag translational fusion and expressed fromEscherichia coli. N-terminal amino acid sequencing of the purified protein revealed the correct sequence, and rabbit polyclonal antisera raised against AS44–331 reacted specifically to Asc10 expressed from E. faecalis OG1SSp, but not to other proteins as judged by Western blot analysis. Using these antisera, flow cytometry analysis demonstrated that antibodies to AS44–331 bound to a surface-exposed region of Asc10. Furthermore, antibodies specific for AS44–331were opsonic for E. faecalis expressing Asc10 in vitro but not for cells that did not express Asc10. New Zealand White rabbits immunized with AS44–331 were challenged intravenously withE. faecalis cells constitutively expressing Asc10 in the rabbit model of experimental endocarditis. Highly immune animals did not show significant differences in clearance of organisms from the blood or spleen or in formation of vegetations on the aortic valve, in comparison with nonimmune animals. Although in vivo expression of Asc10 was demonstrated by immunohistochemistry, these experiments provide evidence that immunity to Asc10 does not play a role in protection from experimental infective endocarditis due toE. faecalis and may have important implications for the development of immunological approaches to combat enterococcal endocarditis.

scholarly journals Interactions between Triazoles and Amphotericin B against Cryptococcus neoformans

2000 ◽  
Vol 44 (9) ◽  
pp. 2435-2441 ◽  
Author(s):  
Francesco Barchiesi ◽  
Anna M. Schimizzi ◽  
Francesca Caselli ◽  
Andrea Novelli ◽  
Stefania Fallani ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Clinical Laboratory ◽  
Fungal Infections ◽  
National Committee ◽  
Positive Interaction ◽  
Pronounced Increase

ABSTRACT The interaction of amphotericin B (AmB) and azole antifungal agents in the treatment of fungal infections is still a controversial issue. A checkerboard titration broth microdilution-based method that adhered to the recommendations of the National Committee for Clinical Laboratory Standards was applied to study the in vitro interactions of AmB with fluconazole (FLC), itraconazole (ITC), and the new investigational triazole SCH 56592 (SCH) against 15 clinical isolates ofCryptococcus neoformans. Synergy, defined as a fractional inhibitory concentration (FIC) index of ≤0.50, was observed for 7% of the isolates in studies of the interactions of both FLC-AmB and ITC-AmB and for 33% of the isolates in studies of the SCH-AmB interactions; additivism (FICs, >0.50 to 1.0) was observed for 67, 73, and 53% of the isolates in studies of the FLC-AmB, ITC-AmB, and SCH-AmB interactions, respectively; indifference (FICs, >1.0 to ≤2.0) was observed for 26, 20, and 14% of the isolates in studies of the FLC-AmB, ITC-AmB, and SCH-AmB interactions, respectively. Antagonism (FIC >2.0) was not observed. When synergy was not achieved, there was still a decrease, although not as dramatic, in the MIC of one or both drugs when they were used in combination. To investigate the effects of FLC-AmB combination therapy in vivo, we established an experimental model of systemic cryptococcosis in BALB/c mice by intravenous injection of cells of C. neoformans 2337, a clinical isolate belonging to serotype D against which the combination of FLC and AmB yielded an additive interaction in vitro. Both survival and tissue burden studies showed that combination therapy was more effective than FLC alone and that combination therapy was at least as effective as AmB given as a single drug. On the other hand, when cells of C. neoformans 2337 were grown in FLC-containing medium, a pronounced increase in resistance to subsequent exposures to AmB was observed. In particular, killing experiments conducted with nonreplicating cells showed that preexposure to FLC abolished the fungicidal activity of the polyene. However, this apparent antagonism was not observed in vivo. Rather, when the two drugs were used sequentially for the treatment of systemic murine cryptococcosis, a reciprocal potentiation was often observed. Our study shows that (i) the combination of triazoles and AmB is significantly more active than either drug alone against C. neoformans in vitro and (ii) the concomitant or sequential use of FLC and AmB for the treatment of systemic murine cryptococcosis results in a positive interaction.

Efficacy of Combination of N-acetylcysteine, Gentamicin, and Amphotericin B for Prevention of Microbial Colonization of Ventricular Assist Devices

2009 ◽  
Vol 30 (2) ◽  
pp. 190-192 ◽  
Author(s):  
Maria D. Hernandez ◽  
Mohammad D. Mansouri ◽  
Saima Aslam ◽  
Barry Zeluff ◽  
Rabih O. Darouiche
Keyword(s):  
Antimicrobial Activity ◽  
Amphotericin B ◽  
Rabbit Model ◽  
Microbial Colonization ◽  
Ventricular Assist Devices ◽  
Ventricular Assist ◽  
In Vivo Efficacy ◽  
Assist Devices

We assessed the in vitro antimicrobial activity and the in vivo efficacy of dipping ventricular assist devices in a combination of N-acetylcysteine, gentamicin, and amphotericin B (NAC/G/A). Ventricular assist devices dipped in NAC/G/A exhibited broad-spectrum antimicrobial activity in vitro and were less likely than undipped devices to become colonized with Staphylococcus aureus in a rabbit model.

scholarly journals In Vivo Activity of Posaconazole against Mucor spp. in an Immunosuppressed-Mouse Model

2002 ◽  
Vol 46 (7) ◽  
pp. 2310-2312 ◽  
Author(s):  
Qiu N. Sun ◽  
Laura K. Najvar ◽  
Rosie Bocanegra ◽  
David Loebenberg ◽  
John R. Graybill
Keyword(s):  
Body Weight ◽  
Mouse Model ◽  
Amphotericin B ◽  
Immunosuppressed Mouse ◽  
Tissue Burden

ABSTRACT The in vivo activities of posaconazole, itraconazole, and amphotericin B in neutropenic mice with zygomycosis were compared. The in vitro MICs of posaconazole and itraconazole for the strains of Mucor spp. used in this study ranged from 0.125 to 8 μg/ml and 0.25 to 8 μg/ml, respectively. The in vitro MIC range for amphotericin B is 0.125 to 0.25 μg/ml. At twice-daily doses of ≥15 mg/kg of body weight, posaconazole prolonged the survival of the mice and reduced tissue burden.

scholarly journals Efficacy and Pharmacokinetics of the Combination of OP0595 and Cefepime in a Mouse Model of Pneumonia Caused by Extended-Spectrum-Beta-Lactamase-Producing Klebsiella pneumoniae

2017 ◽  
Vol 61 (7) ◽  
Author(s):  
Norihito Kaku ◽  
Kosuke Kosai ◽  
Kazuaki Takeda ◽  
Naoki Uno ◽  
Yoshitomo Morinaga ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Klebsiella Pneumoniae ◽  
Mouse Model ◽  
Therapy Group ◽  
Saline Control ◽  
Pharmacokinetic Analysis ◽  
Beta Lactamase ◽  
Extended Spectrum Beta Lactamase ◽  
Extended Spectrum

ABSTRACT OP0595 (RG6080) is a novel diazabicyclooctane that inhibits class A and C serine beta-lactamases. Although the combination of OP0595 and cefepime (FEP) showed good in vitro activity against extended-spectrum-beta-lactamase (ESBL)-producing pathogens, the effect of the combination therapy against severe infections, such as pneumonia or bacteremia, remains unknown in vivo. In this study, we investigated the efficacy and pharmacokinetics of the combination therapy of OP0595 and FEP in a mouse model of pneumonia caused by Klebsiella pneumoniae harboring SHV- and CTX-M-9-type ESBLs. The infected BALB/c mice were intraperitoneally administered saline (control), 100 mg/kg of body weight of FEP, 20 mg/kg of OP0595, or both FEP and OP0595, twice a day. The MIC of FEP against the bacteria was 8 mg/liter and markedly improved to 0.06 mg/liter with the addition of 0.5 mg/ml of OP0595. In the survival study, the combination of FEP and OP0595 significantly improved the survival rate compared with that reported with either OP0595 or FEP alone (P < 0.001). The number of bacteria in the lungs and blood significantly decreased in the combination therapy group compared to that reported for the monotherapy groups (P < 0.001). In addition, the in vivo effect depended on the dose of FEP. However, pharmacokinetic analysis revealed that the percentage of time above MIC remained constant when increasing the dose of FEP in combination with 20 mg/kg of OP0595. The results of our study demonstrated the in vivo effectiveness of the combination of OP0595 and FEP.

scholarly journals AAV-mediated expression of anti-tau scFvs decreases tau accumulation in a mouse model of tauopathy

2017 ◽  
Vol 214 (5) ◽  
pp. 1227-1238 ◽  
Author(s):  
Christina Ising ◽  
Gilbert Gallardo ◽  
Cheryl E.G. Leyns ◽  
Connie H. Wong ◽  
Hong Jiang ◽  
...  
Keyword(s):  
Mouse Model ◽  
Passive Immunization ◽  
Single Chain ◽  
Proinflammatory Response ◽  
Adeno Associated Virus ◽  
Single Chain Variable Fragments ◽  
Novel Strategy ◽  
Progressive Accumulation ◽  
The Brain

Tauopathies are characterized by the progressive accumulation of hyperphosphorylated, aggregated forms of tau. Our laboratory has previously demonstrated that passive immunization with an anti-tau antibody, HJ8.5, decreased accumulation of pathological tau in a human P301S tau-expressing transgenic (P301S-tg) mouse model of frontotemporal dementia/tauopathy. To investigate whether the Fc domain of HJ8.5 is required for the therapeutic effect, we engineered single-chain variable fragments (scFvs) derived from HJ8.5 with variable linker lengths, all specific to human tau. Based on different binding properties, we selected two anti-tau scFvs and tested their efficacy in vivo by adeno-associated virus–mediated gene transfer to the brain of P301S-tg mice. The scFvs significantly reduced levels of hyperphosphorylated, aggregated tau in brain tissue of P301S-tg mice, associated with a decrease in detergent-soluble tau species. Interestingly, these mice showed substantial levels of scFvs in the cerebrospinal fluid without significant effects on total extracellular tau levels. Therefore, our study provides a novel strategy for anti-tau immunotherapeutics that potentially limits a detrimental proinflammatory response.

Sign in / Sign up

Export Citation Format

Share Document