Targeting dexamethasone to macrophages in a porcine endotoxemic model.
OBJECTIVE
Macrophages are important cells in immunity and the main producers of pro-inflammatory cytokines. The main objective was to evaluate if specific delivery of glucocorticoid to the macrophage receptor CD163 is superior to systemic glucocorticoid therapy in dampening the cytokine response to lipopolysaccharide infusion in pigs.


METHODS
Two randomized, placebo-controlled trials.


METHODS
University hospital laboratory.


METHODS
Female farm-bred pigs (26-31 kg).


METHODS
A humanized antibody that binds to pig and human CD163 was produced, characterized, and conjugated with dexamethasone. In the first study (total n = 12), pigs were randomly assigned to four groups: 1) saline; 2) dexamethasone (1.0 mg/kg); 3) dexamethasone (0.02 mg/kg); and 4) anti-CD163-conjugated dexamethasone (0.02 mg/kg). In the second study (total n = 36), two additional groups were included in addition to the four original groups: 5) anti-CD163-conjugated dexamethasone (0.005 mg/kg); 6) unconjugated anti-CD163. Treatments were given 20 hours prior to infusion of lipopolysaccharide (1 µg × kg × h) for 5 hours. Blood samples were analyzed for cytokines, cortisol, and adrenocorticotropic hormone.


RESULTS
In the saline group, lipopolysaccharide increased cytokine and plasma cortisol levels. In both studies, dexamethasone (1 mg/kg) and anti-CD163 dexamethasone (0.02 mg/kg) uniformly attenuated tumor necrosis factor-α peak levels (both p < 0.05) compared with low-dose dexamethasone (0.02 mg/kg). However, dexamethasone 1 mg/kg significantly suppressed plasma cortisol and adrenocorticotropic hormone levels compared with anti-CD163 dexamethasone (0.02 mg/kg; p < 0.05). No significant hemodynamic difference existed between groups. The anti-CD163 dexamethasone drug conjugate exhibited a fast plasma clearance, with a half-life of approximately 5-8 minutes.


CONCLUSIONS
Targeted delivery of dexamethasone to macrophages using a humanized CD163 antibody as carrier exhibits anti-inflammatory effects comparable with 50 times higher concentrations of free dexamethasone and does not inhibit endogenous cortisol production. This antibody-drug complex showing similar affinity and specificity for human CD163 is, therefore, a promising drug candidate in this novel type of anti-inflammatory therapy.
1Department of Anesthesiology, Aarhus University HospitalAarhusDenmark. 2Cytoguide ApS, Incuba Science ParkAarhusDenmark. 3Department of Clinical Biochemistry, Aarhus University HospitalAarhusDenmark. 4Department of Biomedicine, University of AarhusAarhusDenmark.
Asger
A
Granfeldt
Christine Lodberg
CL
Hvas
Jonas Heilskov
JH
Graversen
Peter Astrup
PA
Christensen
Mikkel Due
MD
Petersen
Gabriela
G
Anton
Pia
P
Svendsen
Christoffer
C
Sølling
Anders
A
Etzerodt
Else
E
Tønnesen
Søren Kragh
SK
Moestrup
Holger Jon
HJ
Møller
D000818:Animals; D015703:Antigens, CD / Q000008:administration & dosage* / Q000494:pharmacology; D015214:Antigens, Differentiation, Myelomonocytic / Q000008:administration & dosage* / Q000494:pharmacology; D003907:Dexamethasone / Q000008:administration & dosage* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004337:Drug Carriers / Q000494:pharmacology*; D019446:Endotoxemia / Q000188:drug therapy*; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage* / Q000494:pharmacology; D018836:Inflammation Mediators / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000378:metabolism*; D011897:Random Allocation; D011956:Receptors, Cell Surface / Q000008:administration & dosage*; D013552:Swine; D000098902:CD163 Antigen
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000098902:CD163 Antigen; D004337:Drug Carriers; D005938:Glucocorticoids; D018836:Inflammation Mediators; D008070:Lipopolysaccharides; D011956:Receptors, Cell Surface; D003907:Dexamethasone