Shortened Versions of Cell-Penetrating Peptide Penetratin Can Cross Corneal Tissue
Synthetic shorter analogues of the cell-penetrating peptide penetratin showed measurable ability to cross porcine corneal tissue, though none matched the full-length peptide.
Quick Facts
What This Study Found
All synthesized penetratin analogues demonstrated measurable trans-corneal diffusion despite their hydrophilic nature and ~1.6 kDa size, though none achieved the penetration efficiency of full-length penetratin.
Key Numbers
~1.6 kDa molecular weight; all analogs showed trans-corneal diffusion; none matched full-length penetratin (16 aa)
How They Did This
Synthesized fluorescently labeled short analogues of penetratin and its reversed sequence via mimotopic approach, then tested trans-corneal permeation ex vivo using freshly explanted porcine corneas. Structural analysis performed via circular dichroism.
Why This Research Matters
Eye drug delivery is challenging because the cornea blocks most molecules. Cell-penetrating peptides could carry drugs across this barrier without invasive procedures like injections.
The Bigger Picture
This work contributes to the broader effort of developing non-invasive eye drug delivery systems. If CPP carriers can be optimized, they could replace or reduce the need for eye injections in treating conditions like glaucoma, infections, or macular degeneration.
What This Study Doesn't Tell Us
Preliminary results only. Ex vivo porcine tissue may not fully replicate living human cornea. No therapeutic cargo was tested — only the peptide carriers themselves. No clear structure-activity relationship was established.
Questions This Raises
- ?Can these analogues carry actual drug molecules across the cornea, not just fluorescent labels?
- ?What happens to the peptides within corneal layers — do they distribute evenly or accumulate?
- ?Could combining shorter analogues improve penetration to match full-length penetratin?
Trust & Context
- Key Stat:
- All analogues penetrated Every shortened penetratin variant showed measurable trans-corneal diffusion
- Evidence Grade:
- Preliminary — ex vivo testing on animal tissue with no therapeutic payload; early-stage proof of concept.
- Study Age:
- Published in 2020; this is early-stage work that likely requires further optimization before advancing.
- Original Title:
- Synthesis and Ex Vivo Trans-Corneal Permeation of Penetratin Analogues as Ophthalmic Carriers: Preliminary Results.
- Published In:
- Pharmaceutics, 12(8) (2020)
- Authors:
- Pescina, Silvia(2), Sala, Marina, Scala, Maria Carmina, Santi, Patrizia, Padula, Cristina, Campiglia, Pietro, Ostacolo, Carmine, Nicoli, Sara
- Database ID:
- RPEP-05064
Evidence Hierarchy
Frequently Asked Questions
What is penetratin and why is it useful for eye drugs?
Penetratin is a 16-amino-acid peptide that naturally crosses cell membranes. Researchers hope to use it (or shorter versions) to carry drug molecules through the cornea, potentially replacing eye injections with drops.
Why did they use pig corneas instead of human eyes?
Porcine corneas are structurally similar to human corneas and are commonly used in ex vivo permeation studies as an ethical and practical alternative to human tissue in early research.
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Cite This Study
https://rethinkpeptides.com/research/RPEP-05064APA
Pescina, Silvia; Sala, Marina; Scala, Maria Carmina; Santi, Patrizia; Padula, Cristina; Campiglia, Pietro; Ostacolo, Carmine; Nicoli, Sara. (2020). Synthesis and Ex Vivo Trans-Corneal Permeation of Penetratin Analogues as Ophthalmic Carriers: Preliminary Results.. Pharmaceutics, 12(8). https://doi.org/10.3390/pharmaceutics12080728
MLA
Pescina, Silvia, et al. "Synthesis and Ex Vivo Trans-Corneal Permeation of Penetratin Analogues as Ophthalmic Carriers: Preliminary Results.." Pharmaceutics, 2020. https://doi.org/10.3390/pharmaceutics12080728
RethinkPeptides
RethinkPeptides Research Database. "Synthesis and Ex Vivo Trans-Corneal Permeation of Penetratin..." RPEP-05064. Retrieved from https://rethinkpeptides.com/research/pescina-2020-synthesis-and-ex-vivo
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.