Scientific Name: B7-33
Clinical Test Expectation:Reducing fibrosis in acute and chronic diseases like heart failure, lung inflammation, and the kidneys. Aids Sperm motility, testicular descent, joint health, preeclampsia, wound healing.
MG Strength: 6 mg per vial
Detailed Product Information
B7‐33, a Functionally Selective Relaxin Receptor 1 Agonist, Attenuates Myocardial Infarction–Related Adverse Cardiac Remodeling in Mice
Human relaxin‐2 is a peptide hormone capable of pleiotropic effects in several organ systems. Its recombinant formulation (serelaxin) has been demonstrated to reduce infarct size and prevent excessive scar formation in animal models of cardiac ischemia‐reperfusion injury. B7‐33, a synthetically designed peptide analogous to B‐chain of relaxin‐2, invokes signaling at relaxin family peptide receptor 1 (cognate receptor for relaxin‐2) by preferentially phosphorylating the mitogen‐activated protein kinase extracellular signal‐regulated kinase 1/2. We sought to investigate the effects of B7‐33 treatment post ischemia‐reperfusion injury in mice.
Methods and Results
Adult male CD1 mice were subjected to ischemia‐reperfusion via ligation of left anterior descending artery for 30 minutes, followed by 24 hours or 7 days of reperfusion. Echocardiography was performed to assess cardiac function, and cardiac tissue was stained to determine infarct size at 24 hours. B7‐33 significantly reduced infarct size (21.99% versus 45.32%; P=0.02) and preserved fractional shortening (29% versus 23%; P=0.02) compared with vehicle. The difference in fractional shortening further increased at 7 days post myocardial infarction (29% versus 20% for B7‐33 and vehicle groups, respectively). In vitro, primary cardiomyocytes were isolated from adult hearts and subjected to simulated ischemia‐reperfusion injury (simulated ischemia reoxygenation). B7‐33 (50 and 100 nmol/L) improved cell survival and reduced the expression of GRP78 (glucose regulated protein), an endoplasmic reticulum stress marker. Subsequently, B7‐33 (100 nmol/L) reduced tunicamycin (2.5 μg/mL) induced upregulation of GRP78 in an extracellular signal‐regulated kinase 1/2–dependent manner.
B7-33 replicates the vasoprotective functions of human relaxin-2 (serelaxin)
Recombinant H2 relaxin (serelaxin) has gained considerable attention as a new vasoprotective drug, largely due to its potential therapeutic effects in heart failure and fibrosis. However, serelaxin is laborious and costly to produce. A single-chain peptidomimetic, B7-33, has been developed to overcome these problems but little is known about its biological actions in the vascular system. This study first compared the rapid vascular effects of an acute bolus injection of B7-33 compared with serelaxin. Male Wistar rats received a tail vein injection of placebo (20mM sodium acetate), B7-33 (13.3μg/kg) or serelaxin (26.6μg/kg). Three hours later vascular function in the mesenteric artery, small renal artery and abdominal aorta was assessed by wire myography. B7-33 and serelaxin selectively enhanced bradykinin-mediated endothelium-dependent relaxation in the rat mesenteric artery by increasing endothelium-derived hyperpolarization, but had no overall effects on relaxation in the small renal artery or aorta. We then compared the actions of B7-33 and serelaxin in an ex vivo model of vascular disease using virgin female mouse mesenteric arteries pre-incubated in placental trophoblast conditioned media to induce endothelial dysfunction characteristic of preeclampsia. Co-incubation of these arteries in trophoblast conditioned media with B7-33 or serelaxin (15, 30nM) prevented the development of endothelial dysfunction. In conclusion, equimolar doses of B7-33 replicated the acute beneficial vascular effects of serelaxin in rat mesenteric arteries and also prevented endothelial dysfunction induced by placental trophoblast conditioned media in mouse mesenteric arteries. Therefore, B7-33 should be considered as a cost-effective vasoactive therapeutic in cardiovascular diseases, including preeclampsia.
B7‐33 confers acute cardioprotection and limits myocardial infarction–related adverse remodeling in mice by attenuating cardiomyocyte death and endoplasmic reticulum stress as well as preserving cardiac function.
Mixing and our recommended dosage
You inject 2ml water into the vial of B7-33 from the water vial. 1 full syringe is 1ml. You then wait for the vial powder content to dissolve ON ITS OWN. DO NOT SHAKE THE VIAL TO MIX POWDER. Once dissolved and clear in colour you draw out 0.25 – 0.3 on the syringe each morning before breakfast and inject it into the tummy under the skin into the fatty skin layer. A vial should last 7-8 days.
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