Diabetic Patients Have Reduced Skin Defense Peptide RNase 7, and Metformin May Further Suppress It
Diabetic patients had lower skin levels of the antimicrobial peptide RNase 7 regardless of ulcer status, and metformin — the most common diabetes drug — further reduced its expression in lab tests.
Quick Facts
What This Study Found
RNase 7 was significantly decreased in skin of diabetic patients with and without foot ulcers compared to healthy donors. Metformin reduced RNase 7 expression in keratinocytes in vitro, while calcitriol, phenyl butyrate, and L-isoleucine did not restore it.
Key Numbers
4 defense peptides measured; RNase 7 decreased in both diabetic groups; metformin reduced RNase 7 in vitro
How They Did This
Observational study with skin biopsies from three groups: DFU patients (Wagner grade 3), diabetic patients without ulcers, and healthy donors. qPCR and immunohistochemistry for RNase 7, cathelicidin, HBD-2, and psoriasin. In vitro keratinocyte stimulation with metformin, glyburide, insulin, calcitriol, phenyl butyrate, and L-isoleucine.
Why This Research Matters
Diabetic foot ulcers affect millions and can lead to amputation. If metformin — taken by most type 2 diabetics — further reduces skin antimicrobial defenses, this has major clinical implications for wound management.
The Bigger Picture
This study highlights an underappreciated connection between diabetes medication and innate immunity. It raises the broader question of how commonly prescribed drugs may inadvertently impair immune defenses in vulnerable patients.
What This Study Doesn't Tell Us
Sample sizes not specified. In vitro metformin effect on keratinocytes may not reflect in vivo skin responses. Correlation between RNase 7 reduction and infection outcomes not established. Known inducers failed to restore expression.
Questions This Raises
- ?Do diabetic patients on metformin have higher rates of foot ulcer infections compared to those on other medications?
- ?What mechanisms cause diabetes itself to reduce RNase 7 expression?
- ?Are there alternative compounds that can restore RNase 7 in diabetic skin?
Trust & Context
- Key Stat:
- Metformin suppresses RNase 7 The most commonly used diabetes drug further reduced an already-depleted skin defense peptide in diabetic patients
- Evidence Grade:
- Preliminary — observational biopsy data combined with in vitro drug testing. No clinical outcome data linking RNase 7 levels to infection risk.
- Study Age:
- Published in 2020; the impact of diabetes medications on innate immunity remains an important area of investigation.
- Original Title:
- Host Defense Peptide RNase 7 Is Down-regulated in the Skin of Diabetic Patients with or without Chronic Ulcers, and its Expression is Altered with Metformin.
- Published In:
- Archives of medical research, 51(4), 327-335 (2020)
- Authors:
- Rodríguez-Carlos, Adrian, Trujillo, Valentin, Gonzalez-Curiel, Irma, Marin-Luevano, Sara, Torres-Juarez, Flor, Santos-Mena, Alan, Rivas-Santiago, Cesar, Enciso-Moreno, Jose A, Zaga-Clavellina, Veronica, Rivas-Santiago, Bruno
- Database ID:
- RPEP-05096
Evidence Hierarchy
Watches what happens naturally without intervening.
What do these levels mean? →Frequently Asked Questions
What is RNase 7 and why does it matter for diabetic feet?
RNase 7 is an antimicrobial peptide produced by skin cells that helps fight bacteria. When levels are low — as found in diabetic patients — the skin is more vulnerable to infection, which is especially dangerous for diabetic feet where infections can lead to amputation.
Should diabetic patients stop taking metformin because of this finding?
No — this is an early in vitro finding that needs clinical confirmation. Metformin has many proven benefits for diabetes. However, the finding warrants further study, especially in patients with recurring foot ulcers.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-05096APA
Rodríguez-Carlos, Adrian; Trujillo, Valentin; Gonzalez-Curiel, Irma; Marin-Luevano, Sara; Torres-Juarez, Flor; Santos-Mena, Alan; Rivas-Santiago, Cesar; Enciso-Moreno, Jose A; Zaga-Clavellina, Veronica; Rivas-Santiago, Bruno. (2020). Host Defense Peptide RNase 7 Is Down-regulated in the Skin of Diabetic Patients with or without Chronic Ulcers, and its Expression is Altered with Metformin.. Archives of medical research, 51(4), 327-335. https://doi.org/10.1016/j.arcmed.2020.03.006
MLA
Rodríguez-Carlos, Adrian, et al. "Host Defense Peptide RNase 7 Is Down-regulated in the Skin of Diabetic Patients with or without Chronic Ulcers, and its Expression is Altered with Metformin.." Archives of medical research, 2020. https://doi.org/10.1016/j.arcmed.2020.03.006
RethinkPeptides
RethinkPeptides Research Database. "Host Defense Peptide RNase 7 Is Down-regulated in the Skin o..." RPEP-05096. Retrieved from https://rethinkpeptides.com/research/rodriguez-carlos-2020-host-defense-peptide-rnase
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.