A Model-Based Pharmacokinetic/Pharmacodynamic Analysis of the Combination of Amoxicillin and Monophosphoryl Lipid A Against S. pneumoniae in Mice

Combining amoxicillin with the immunostimulatory toll-like receptor 4 agonist monophosphoryl lipid A (MPLA) represents an innovative approach for enhancing antibacterial treatment success. Exploiting pharmacokinetic and pharmacodynamic data from an infection model of Streptococcus pneumoniae infected mice, we aimed to evaluate the preclinical exposure-response relationship of amoxicillin with MPLA coadministration and establish a link to survival. Antibiotic serum concentrations, bacterial numbers in lung and spleen and survival data of mice being untreated or treated with amoxicillin (four dose levels), MPLA, or their combination were analyzed by nonlinear mixed-effects modelling and time-to-event analysis using NONMEM® to characterize these treatment regimens. On top of a pharmacokinetic interaction, regarding the pharmacodynamic effects the combined treatment was superior to both monotherapies: The amoxicillin efficacy at highest dose was increased by a bacterial reduction of 1.74 log10 CFU/lung after 36 h and survival was increased 1.35-fold to 90.3% after 14 days both compared to amoxicillin alone. The developed pharmacometric pharmacokinetic/pharmacodynamic disease-treatment-survival models provided quantitative insights into a novel treatment option against pneumonia revealing a pharmacokinetic interaction and enhanced activity of amoxicillin and the immune system stimulator MPLA in combination. Further development of this drug combination flanked with pharmacometrics towards the clinical setting seems promising.

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Faculty Opinions recommendation of The vaccine adjuvant monophosphoryl lipid A as a TRIF-biased agonist of TLR4.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1087287.540302 ◽

2007 ◽

Author(s):

Rino Rappuoli

Keyword(s):

Lipid A ◽

Vaccine Adjuvant ◽

Monophosphoryl Lipid A ◽

Monophosphoryl Lipid ◽

Biased Agonist

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Monophosphoryl lipid A: an effective adjuvant for potentiating mucosal immune responses

Journal of Endotoxin Research ◽

10.1177/09680519990050030305 ◽

1999 ◽

Vol 5 (3) ◽

pp. 181-182 ◽

Cited By ~ 3

Author(s):

Suzanne M. Michalek ◽

Noel K. Childers ◽

Terry Greenway ◽

George Hajishengallis ◽

J. Terry Ulrich

Keyword(s):

Immune Responses ◽

Lipid A ◽

Monophosphoryl Lipid A ◽

Monophosphoryl Lipid ◽

Mucosal Immune Responses

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Monophosphoryl lipid A induces protection against LPS in medullary thick ascending limb through a TLR4-TRIF-PI3K signaling pathway

AJP Renal Physiology ◽

10.1152/ajprenal.00064.2017 ◽

2017 ◽

Vol 313 (1) ◽

pp. F103-F115 ◽

Cited By ~ 10

Author(s):

Bruns A. Watts ◽

Thampi George ◽

Edward R. Sherwood ◽

David W. Good

Keyword(s):

Bacterial Infections ◽

Lipid A ◽

Thick Ascending Limb ◽

Akt Inhibitor ◽

Erk Activation ◽

Akt Phosphorylation ◽

Medullary Thick Ascending Limb ◽

Monophosphoryl Lipid A ◽

Monophosphoryl Lipid

Monophosphoryl lipid A (MPLA) is a detoxified derivative of LPS that induces tolerance to LPS and augments host resistance to bacterial infections. Previously, we demonstrated that LPS inhibits [Formula: see text] absorption in the medullary thick ascending limb (MTAL) through a basolateral Toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88)-ERK pathway. Here we examined whether pretreatment with MPLA would attenuate LPS inhibition. MTALs from rats were perfused in vitro with MPLA (1 µg/ml) in bath and lumen or bath alone for 2 h, and then LPS was added to (and MPLA removed from) the bath solution. Pretreatment with MPLA eliminated LPS-induced inhibition of [Formula: see text] absorption. In MTALs pretreated with MPLA plus a phosphatidylinositol 3-kinase (PI3K) or Akt inhibitor, LPS decreased [Formula: see text] absorption. MPLA increased Akt phosphorylation in dissected MTALs. The Akt activation was eliminated by a PI3K inhibitor and in MTALs from TLR4−/−or Toll/IL-1 receptor domain-containing adaptor-inducing IFN-β (TRIF)−/−mice. The effect of MPLA to prevent LPS inhibition of [Formula: see text] absorption also was TRIF dependent. Pretreatment with MPLA prevented LPS-induced ERK activation; this effect was dependent on PI3K. MPLA alone had no effect on [Formula: see text] absorption, and MPLA pretreatment did not prevent ERK-mediated inhibition of [Formula: see text] absorption by aldosterone, consistent with MPLA's low toxicity profile. These results demonstrate that pretreatment with MPLA prevents the effect of LPS to inhibit [Formula: see text] absorption in the MTAL. This protective effect is mediated directly through MPLA stimulation of a TLR4-TRIF-PI3K-Akt pathway that prevents LPS-induced ERK activation. These studies identify detoxified TLR4-based immunomodulators as novel potential therapeutic agents to prevent or treat renal tubule dysfunction in response to bacterial infections.

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