B7-33

Relaxin B7-33, Single-chain relaxin analog

A synthetic peptide derived from the B-chain of human relaxin-2, exhibiting potent anti-fibrotic and cardioprotective effects through selective RXFP1 activation.

Molecular Profile

Formula C₁₃₁H₂₂₉N₄₁O₃₆S

Mol. Weight 2986.58 g/mol

Sequence Gly-Glu-Pro-Pro...

Clinical Data Trials

Scientific Data Studies

Route	Dosage	Bioavailability
Intravenous (IV) 1 mg/kg	1 mg/kg	Complete (100%)	INT
Subcutaneous (SC) 3 mg/kg	3 mg/kg	High (80%)	SUB
Intraperitoneal (IP) 0.25 mg/kg	0.25 mg/kg	High (90%)	INT

How It Works

How It Works: B7-33 functions as a selective agonist of the relaxin family peptide receptor 1 (RXFP1), promoting anti-fibrotic effects primarily through biased signaling that avoids cAMP activation while inhibiting fibrosis pathways.

RXFP1-AT2R Heterodimerization: Forms complexes that inhibit TGF-β1 signaling, reducing myofibroblast differentiation and collagen deposition.
Matrix Remodeling: Upregulates matrix metalloproteinase-2 (MMP-2) to degrade excess extracellular matrix.
Vasoprotection: Stimulates nitric oxide production, leading to vasodilation and reduced vascular stiffness.
Cardioprotection: Attenuates endoplasmic reticulum stress and apoptosis in cardiac tissues.

Pairs Well With

Latest Studies

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Utility 2

pubmed Aug 11, 2023

Further Developments towards a Minimal Potent Derivative of Human Relaxin-2.

Handley. Thomas N G TNG; Praveen. Praveen P; Tailhades. Julien J; Wu. Hongkang H...

Scientists are tweaking a tiny piece of a hormone called relaxin (named B7‑33) to make it more stable and effective at fighting tissue scarring. In lab cells that naturally have the relaxin receptor, B7‑33 works as well as the full hormone, and it has helped reduce organ fibrosis in animal studies. The researchers are now trying chemical tricks (Aib substitution and hydrocarbon stapling) to make the peptide hold its shape better and act stronger.

Utility 3

pubmed Apr 1, 2023

A Lipidated Single-B-Chain Derivative of Relaxin Exhibits Improved In Vitro Serum Stability without Altering Activity.

Praveen. Praveen P; Wang. Chao C; Handley. Thomas N G TNG; Wu. Hongkang H; Samue...

Scientists made a simpler version of the hormone relaxin (called B7-33) that can still activate its receptor, but it disappears from blood very quickly. By attaching a fatty‑acid chain with the right length, they stretched its half‑life in test‑tube serum from about 6 minutes to roughly an hour, without losing activity. The next step is to test this longer‑lasting version in animals.

Utility 3

pubmed Feb 6, 2023

The single-chain relaxin mimetic, B7-33, maintains the cardioprotective effects of relaxin and more rapidly reduces left ventricular fibrosis compared to perindopril in an experimental model of cardiomyopathy.

Alam. Fariha F; Gaspari. Tracey A TA; Kemp-Harper. Barbara K BK; Low. Edward E;...

In mice with drug‑induced heart damage, the single‑chain peptide B7‑33 acted like the natural hormone relaxin, cutting heart scarring, inflammation and cell enlargement. It worked as well as relaxin and did these anti‑fibrotic effects faster than the blood‑pressure drug perindopril, which only lowered pressure and didn’t reduce scarring.

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