PulmoBind, an adrenomedullin-based molecular lung imaging tool

Area of Science:

• Biomedical imaging
• Radiopharmaceutical chemistry
• Cardiovascular research

Background:

• Adrenomedullin (AM) is a peptide hormone with abundant binding sites in the pulmonary vasculature.
• AM shows potential as a targeting agent for molecular imaging of the pulmonary circulation.
• Existing imaging agents may have safety concerns for clinical application.

Purpose of the Study:

• To design and evaluate a novel adrenomedullin-based compound for molecular imaging of the pulmonary circulation.
• To ensure the designed compound possesses optimal imaging properties and a favorable safety profile for clinical use.

Main Methods:

• Synthesis of cyclic AM analogs using solid-phase peptide synthesis.
• Evaluation of (99m)Tc labeling efficiency and in vivo lung uptake.
• Biodistribution, hemodynamic assessment, and dosimetric analysis in animal models (dogs and rats).

Main Results:

• A cyclic AM analog (residues 22-52) with a PEG spacer and tetrapeptide chelator exhibited high labeling efficiency (90.7% ± 0.3%).
• The compound demonstrated significant lung uptake (40% at 10 min) and a favorable safety profile.
• Lung uptake was reduced in a rat model of pulmonary arterial hypertension, indicating disease-specific targeting.

Conclusions:

• The developed (99m)Tc-labeled AM analog is a potential candidate for molecular imaging of pulmonary circulation disorders.
• This compound could aid in the molecular diagnosis of conditions affecting the pulmonary vascular system.
• Further clinical evaluation is warranted to confirm its utility in diagnosing pulmonary circulatory diseases.