Immunomodulatory activities and biomedical applications of melittin and its recent advances

Melittin (MLT), a peptide containing 26 amino acids, is a key constituent of bee venom. It comprises ∼40%-60% of the venom's dry weight and is the main pricing index for bee venom, being the causative factor of pain. The unique properties of MLT extracted from bee venom have made it a very valuable active ingredient in the pharmaceutical industry as this cationic and amphipathic peptide has propitious effects on human health in diverse biological processes. It has the ability to strongly impact the membranes of cells and display hemolytic activity with anticancer characteristics. However, the clinical application of MLT has been limited by its severe hemolytic activity, which poses a challenge for therapeutic use. By employing more efficient mechanisms, such as modifying the MLT sequence, genetic engineering, and nano-delivery systems, it is anticipated that the limitations posed by MLT can be overcome, thereby enabling its wider application in therapeutic contexts. This review has outlined recent advancements in MLT's nano-delivery systems and genetically engineered cells expressing MLT and provided an overview of where the MLTMLT's platforms are and where they will go in the future with the challenges ahead. The focus is on exploring how these approaches can overcome the limitations associated with MLT's hemolytic activity and improve its selectivity and efficacy in targeting cancer cells. These advancements hold promise for the creation of innovative and enhanced therapeutic approaches based on MLT for the treatment of cancer.

Advances in venom peptide drug discovery: where are we at and where are we heading?

Introduction: Animal venoms are a complex mixture of bioactive molecules that have evolved over millions of years for prey capture and defense from predators. Venom consists of many different types of molecules, with disulfide-rich peptides being a major component in most venoms. The study of these potent and highly selective molecules has led to the development of venom-derived drugs for diseases such as type 2 diabetes mellitus and chronic pain. As technologies have improved, more bioactive peptides have been discovered from venomous animals. Many of these molecules may have applications as tools for understanding normal and disease physiology, therapeutics, cosmetics or in agriculture.Areas covered: This article reviews venom-derived drugs approved by the FDA and venom-derived peptides currently in development. It discusses the challenges faced by venom-derived peptide drugs during drug development and the future for venom-derived peptides.Expert opinion: New techniques such as toxin driven discovery are expanding the pipeline of venom-derived peptides. There are many venom-derived peptides currently in preclinical and clinical trials that would have remained undiscovered using traditional approaches. A renewed focus on venoms, with advances in technology, will broaden the diversity of venom-derived peptide therapeutics and expand our knowledge of their molecular targets.

[Intracoronary administration of antithrombotic agents via a perfusion balloon catheter in patients with ST-segment elevation myocardial infarction presenting with massive intraluminal thrombus and failed aspiration]

BACKGROUND

Massive intracoronary thrombus is associated with adverse procedural results including failed aspiration and unfavourable reperfusion. We aim to evaluate the effect of the intracoronary administration of antithrombotic agents via a perfusion catheter in patients with ST-segment elevation myocardial infarction (STEMI) presenting with a large thrombus burden and failed aspiration.

METHODS

We retrospectively analyzed the thrombus burden, the TIMI grade flow, and the myocardial Blush in 25 consecutive STEMI patients with a large thrombus burden and failed manual aspiration, who received intracoronary infusion of glycoprotein IIb/IIIa inhibitors (N=17) or bivalirudine (N=8) via a 6F-infusion catheter (ClearWay™ RX) RESULTS: Mean age was 67±14 years, 16 patients (64 %) presented with anterior STEMI, and 7 (28 %) with cardiogenic shock. Immediately after intracoronary infusion, the TIMI flow grade improved of 2 grades in 7 patients (28 %), and 1 grade in 14 (56 %), a complete resolution of the thrombus was observed in 9 patients, and a >50 % resolution in 12. Blush was improved of 3 grades in 15 patients (60 %), of 2 grades in 7 (28 %), and Blush grade 0 remained in 3. At the end of procedure, we observed normal TIMI 3flow in most patients (92 %), a complete resolution of thrombus in 80 %, and a Blush grade 3 in 68 %.

CONCLUSIONS

In STEMI patients presenting with a large thrombus burden and failed aspiration, intracoronary administration of glycoprotein IIb/IIIa inhibitors or bivalirudin via the perfusion catheter ClearWay™ RX significantly reduced the thrombus burden and improved the TIMI flow and the Blush grade, without bleeding.