A 12-amino-acid cardiac-targeting peptide showed no signs of toxicity in either cell or animal studies, clearing a key hurdle for developing peptide-based heart therapies.
Zero toxicity signalsCTP showed no harmful effects across cell studies, 78 protein channel tests, and comprehensive mouse safety testing including cardiac MRI
What the researchers found
CTP (sequence: APHLSSQYSRT) showed no decrease in human cardiomyocyte viability in vitro. Of 78 protein channels tested, only OPRM1 and COX2 showed any interaction, and neither was expressed in mouse heart tissue. In 60 mice followed for up to 14 days, CTP caused no changes in blood pressure, blood counts, liver function, kidney function, thyroid function, or cardiac size/function on MRI. The peptide appears safe as a cardiac delivery vector.
Why it matters
Delivering drugs specifically to the heart while avoiding other organs is a major unmet need in cardiology. CTP already delivers imaging agents, drugs, nanoparticles, and even miRNA to heart cells within minutes. Demonstrating safety clears a critical hurdle toward human clinical trials.
The numbers in context
CTP is a 12-amino-acid peptide (APHLSSQYSRT). It reaches cardiomyocytes within 5 minutes of intravenous injection.
How the study worked
Combined in vitro and in vivo toxicity assessment. Cell viability tested in human left ventricular myocyte cell line. Ion channel and GPCR profiling across 78 targets. In vivo: 60 CD1 mice (male/female) received CTP at 150 µg/kg, with cohorts euthanized at days 0, 1, 2, 7, and 14 for blood counts, metabolic profiling, and organ function tests. Blood pressure monitored acutely at 10 mg/kg dose. Cardiac MRI before and after injection.
Who was studied
Preclinical toxicity assessment of cardiac-targeting peptide
What this study cannot tell us
Only acute single-dose toxicity tested — chronic administration effects unknown. Mice were tested with CTP alone, not conjugated to any therapeutic cargo (which could change the safety profile). Only 14-day follow-up. No human pharmacokinetic or toxicity data. GLP (good laboratory practice) studies still needed before human trials.
How to read the evidence
Rated moderate: thorough preclinical safety assessment with both in vitro and in vivo components, but single-dose only and not yet tested with therapeutic cargo.
When this study was published
Published in 2024. Represents the latest safety data supporting CTP as a clinical candidate for heart-targeted delivery.
The bigger picture
Heart-targeting peptides could transform cardiology by enabling precise drug delivery to heart muscle cells. If CTP advances to human trials, it could make heart failure treatments more effective with fewer side effects by concentrating drugs where they're needed.
Questions still open
- Will CTP remain safe when conjugated to therapeutic cargo like drugs or miRNA?
- What happens with repeated chronic dosing over months?
- Could CTP be used to deliver gene therapies specifically to the heart?
Common questions
What is a cardiac-targeting peptide?
Is CTP safe?
Read the original research
Toxicity Studies of Cardiac-Targeting Peptide Reveal a Robust Safety Profile.
Pharmaceutics, 16(1)
Citation
Sahagun, Daniella A; Lopuszynski, Jack B; Feldman, Kyle S; Pogodzinski, Nicholas; Zahid, Maliha. (2024). Toxicity Studies of Cardiac-Targeting Peptide Reveal a Robust Safety Profile.. Pharmaceutics, 16(1). https://doi.org/10.3390/pharmaceutics16010073