The Pharmacology of Radiolabeled Cationic Antimicrobial Peptides

Antimicrobial Peptides: Their Role as Infection-Selective Tracers for Molecular Imaging

“…In the case of peptide targeting molecules a covalent bond may be formed between the radionuclide and a suitable free amide residue of Lys and Arg [47]. Using the tyrosine residue may cause problems associated with labelling including nonspecific or poor binding, in vivo instability of the complex, and unwanted alterations to the peptide structure, such as the cleaving of internal disulphide bonds, which can alter its functioning [8]. …”

“…An indirect labelling strategy can be used through addition of chelating agents to the targeting molecule (Figure 5(b)) [8]. Bifunctional chelates have been used to label peptide carrier molecules with radionuclides.…”

“…It is believed that these peptides function as broad-spectrum microbicides and form part of the innate immune system of many eukaryotes, including humans. Regardless of their origin, they share many common properties such as having a net positive charge, being amphipathic and, in most cases, are membrane active [8]. Due to their role in the body as a natural microbicide, these antimicrobial peptides are selectively cytotoxic to bacteria, whilst showing minimal cytotoxicity towards cells of the host organism.…”

FAU (Finkel-Biskis-Reilly murine sarcoma virus (FBR-MuSV) ubiquitously expressed)

“…It is also active against methicillin-resistant Staphylococcus aureus and accumulates at sites of infection in mice (Brouwer et al, 2006). Radiolabelled ubiquicidin has applications in clinical imaging for microbial infections (Brouwer et al, 2008).…”

Estudo terapêutico da gomesina em camundongos com candidíase disseminada e vaginal.

“…A escolha deste radioisotopo foi feita, pois as propriedades físico-químicas do tecnécio-99m, permitem marcar inúmeras estruturas moleculares, além do seu baixo custo podendo ser obtido por um gerador de molibdênio. Outra vantagem do tecnécio-99m é sua meia vida curta de seis horas que proporciona uma baixa radiação para os pacientes e a não contaminação do meio ambiente (BROUWER et al, 2007). A biodistribuição da gomesina revelou que o peptídeo é endereçado para os órgãos de tropismo da Candida: rins; baço e fígado, já nos primeiros minutos após a administração.…”