Biodistribution of a near infrared fluorophore-labeled anti Shiga toxin molecule by non-invasive in vivo optical imaging in mice.

BERENGENO, A.; SALINAS, F.; MARELLI B.; ZYLVERMAN, V.; HIRIART, Y.; SANGUINETI, S.; SALVETTI, N.; ORTEGA, H.

Mar del Plata

Congreso; LXIII Reunión Anual de la Sociedad Argentina de Investigación Clínica (SAIC) Reunión conjunta SAIC, SAI, SAFIS 2018; 2018

SAIC SAI SAFIS

Hemolytic uremic syndrome (HUS) is a multisystemic disorder characterizedby microangiopathic hemolytic anemia, thrombocytopeniaand acute renal damage. Shiga toxin (Stx) producing Escherichiacoli (STEC) O157:H7 is the most common serotype associated withHUS in children younger than 5 years old. Argentina has the highestincidence of HUS in the world. Recently a new treatment capableof neutralizing the toxic effect of Stx and its variants has been developed.The efficacy and potency against Stx1 and Stx2 of F(ab?)2fragments from an equine antiserum were proved in preclinical models.Although the anti-Stx F(ab?)2 pharmacokinetic was shown to besimilar to that of immunoglobulin derived molecules, the tissue distributionand bioaccumulation have not been described. Our objectivewas to evaluate the biodistribution of anti-Stx F(ab?)2 labeled with aNIR fluorophore using an in vivo optical imaging system in mice. The800CW Protein Labeling Kit - HMW was utilized to label the anti-Stxand 5 BALB/cCmedc mice (25 days old) were treated with 10 mg/kg. At 0.5, 1, 2, 4, 6, 8, 12 and 24 h after inoculation images wereacquired using the Pearl Trilogy Image System (LI-COR Biosciences)with Ex/Em setting at 785/820 nm. After in vivo imaging, animalswere sacrificed. Ex vivo imaging after removal of brain, heart, lungs,liver, spleen, kidneys, stomach, intestines, adrenal glands, eyes,seminal vesicles, prostate and bladder was performed. In vivo fluorescencewas observed in large vessels, liver and kidneys at 0.5h after inoculation with a decrease intensity over time. Ex vivo localizationof anti-Stx in liver and kidneys was confirmed. Fluorescencesignal in bladder was detected. This distribution should beassociated with a high vascularization of these organs. Our resultsdemonstrate that in vivo imaging systems are a valuable technologyto understand biodistribution and targeting of new therapeutic biologicalmolecules in experimental models.