GHRH antagonist peptides strengthened lung endothelial barriers through anti-inflammatory pathways, while GHRH itself weakened them, suggesting a potential treatment for acute respiratory distress syndrome.
Barrier-protective vs barrier-disruptiveGHRH antagonists and GHRH itself had opposite effects on lung endothelial barrier integrity — antagonists strengthened it while the native peptide and agonists weakened it.
What the researchers found
GHRH antagonist peptides protected lung endothelial barrier integrity by suppressing activation of MLC2, ERK1/2, and JAK2/STAT3 pathways while increasing P53 and pAMPK levels. In contrast, GHRH itself and the GHRH agonist MR409 disrupted endothelial barrier function through opposite effects on these pathways. Transendothelial resistance measurements confirmed that GHRH antagonists strengthened the barrier while GHRH and its agonists weakened it.
Why it matters
Acute Respiratory Distress Syndrome (ARDS) is a life-threatening condition where the lung's blood vessel barrier breaks down, flooding the lungs with fluid. This study reveals that GHRH peptide antagonists can protect this barrier through multiple anti-inflammatory pathways. Given the limited treatment options for ARDS, GHRH antagonist peptides could represent a new therapeutic approach for this lethal condition.
The numbers in context
GHRH antagonists: suppressed MLC2, ERK1/2, JAK2/STAT3 · increased P53 and pAMPK · increased transendothelial resistance · GHRH and agonist MR409: opposite effects
How the study worked
Researchers used bovine pulmonary arterial endothelial cells to study the effects of GHRH, GHRH agonists (MR409), and GHRH antagonists on intracellular signaling pathways. Protein activation was measured by Western blotting. Endothelial barrier function was assessed by transendothelial electrical resistance measurements.
Who was studied
Bovine pulmonary arterial endothelial cells (in vitro)
What this study cannot tell us
This is an in vitro study using bovine lung cells, and results may not translate directly to intact human lungs or clinical ARDS. Only one cell type was studied, and the complexity of ARDS involves multiple cell types and inflammatory cascades. Specific GHRH antagonist compounds used were not detailed in the abstract. No in vivo validation was provided.
How to read the evidence
This is an in vitro mechanistic study using bovine pulmonary cells. It provides clear evidence for the signaling pathways involved but needs in vivo validation in ARDS animal models and eventually human studies before therapeutic application.
When this study was published
Published in 2019, before the COVID-19 pandemic that dramatically increased interest in ARDS treatments. The concept of GHRH antagonists for lung protection has gained additional relevance since.
The bigger picture
GHRH antagonists were originally developed as anti-cancer peptides, but this study reveals an entirely new therapeutic application: protecting the lung vasculature. The COVID-19 pandemic highlighted how devastating ARDS can be and how few targeted treatments exist. GHRH antagonist peptides add to a growing list of repurposed peptide therapeutics that could address critical care needs.
Questions still open
- Do GHRH antagonists protect lung endothelial barriers in animal models of ARDS?
- Could GHRH antagonists work synergistically with existing ARDS treatments like corticosteroids?
- Is the lung barrier-protective effect specific to certain GHRH antagonist analogs, or is it a class-wide property?
Common questions
What is GHRH and why would blocking it protect the lungs?
What is ARDS and why do we need new treatments?
Read the original research
GHRH antagonists support lung endothelial barrier function.
Tissue barriers, 7(4), 1669989
Citation
Uddin, Mohammad A; Akhter, Mohammad S; Singh, Sitanshu S; Kubra, Khadeja-Tul; Schally, Andrew V; Jois, Seetharama; Barabutis, Nektarios. (2019). GHRH antagonists support lung endothelial barrier function.. Tissue barriers, 7(4), 1669989. https://doi.org/10.1080/21688370.2019.1669989