Identification of Peptides and Proteins in Illegally Distributed Products by MALDI-TOF-MS

An analytical strategy based on matrix-assisted laser desorption/ionization (MALDI) time-of-flight (TOF) mass spectrometry (MS) for identification of peptides and proteins in illegally distributed products is presented. The identified compounds include human growth hormone (hGH), human somatoliberin, anti-obesity drug (AOD), growth hormone releasing peptides (GHRP-2 and GHRP-6), Glycine-GHRP-2 and Glycine-GHRP-6, ipamorelin, insulin aspart and porcine, delta sleep-inducing peptide (DSIP), thymosin β4, insulin like growth factor (IGF), mechano growth factor (MGF), human chorionic gonadotropin (hCG), melanotan II, bremelanotide, dermorphin and body protecting compound (BPC 157). The identification of proteins was mainly based on peptide mass fingerprinting, i.e., bottom up approach, while the smaller peptides were identified through de-novo sequencing. In cases when a reference standard was available, complementary identification was performed by capillary electrophoresis in double-injection mode (DICE), where a suspicious product was compared with the reference standard through two consecutive injections within the same electrophoretic run.

Synthetic Growth Hormone-Releasing Peptides (GHRPs): A Historical Appraisal of the Evidences Supporting Their Cytoprotective Effects

Background: Growth hormone-releasing peptides (GHRPs) constitute a group of small synthetic peptides that stimulate the growth hormone secretion and the downstream axis activity. Mounting evidences since the early 1980s delineated unexpected pharmacological cardioprotective and cytoprotective properties for the GHRPs. However, despite intense basic pharmacological research, alternatives to prevent cell and tissue demise before lethal insults have remained as an empty niche in the clinical armamentarium. Here, we have rigorously reviewed the investigational development of GHRPs and their clinical niching perspectives. Methodology: PubMed/MEDLINE databases, including original research and review articles, were explored. The search design was date escalated from 1980 and included articles in English only. Results and Conclusions: GHRPs bind to two different receptors (GHS-R1a and CD36), which redundantly or independently exert relevant biological effects. GHRPs’ binding to CD36 activates prosurvival pathways such as PI-3K/AKT1, thus reducing cellular death. Furthermore, GHRPs decrease reactive oxygen species (ROS) spillover, enhance the antioxidant defenses, and reduce inflammation. These cytoprotective abilities have been revealed in cardiac, neuronal, gastrointestinal, and hepatic cells, representing a comprehensive spectrum of protection of parenchymal organs. Antifibrotic effects have been attributed to some of the GHRPs by counteracting fibrogenic cytokines. In addition, GHRP family members have shown a potent myotropic effect by promoting anabolia and inhibiting catabolia. Finally, GHRPs exhibit a broad safety profile in preclinical and clinical settings. Despite these fragmented lines incite to envision multiple pharmacological uses for GHRPs, especially as a myocardial reperfusion damage-attenuating candidate, this family of “drugable” peptides awaits for a definitive clinical niche.