Erythrocyte-based analgesic peptides

Hemorphin-Based Analgesia: A Mechanism of Cupping Technique?

Background and Objective

Cupping is a time-honoured traditional healing modality for pain management and remains favoured by professionals and lay people across several cultures today. However, the analgesic mechanism of cupping is still poorly understood. In addition, clinical guidelines for standardized applications of cupping are currently lacking. The awareness of cupping marks has provoked curiosity about the connection between skin color changes and their benefit for local pain relief. Computer simulation is a promising approach for numerical modeling the cupping-evoked erythrocyte emigration. Quantitative proteomic profiling of cupping-induced blister fluid exhibited a significant decrease in the abundance of haemoglobin β subunit. This finding provides a critical clue to paint a novel picture of the mechanism behind cupping. The hemorphins are a set of non-classical opioid peptides derived from the proteolysis of haemoglobin β subunit. In the present study, a probable mechanism of hemorphin-based cupping analgesia is proposed. The hemorphin could also act as a potential biomarker for objective and timely quantitative clinical assessment of cupping in the management of pain conditions. A seminal theory may open a new avenue for future translational research on promoting the efficacy and safety of cupping analgesia.

Conclusion

The local analgesic effect of cupping is probable in the context of haemoglobin degradation that bestows the appearance of hemorphins along with engaging opioid receptor signalling. Exploring the potential novel mechanism of cupping analgesia facilitates seeking non-pharmacologic pain interventions.

Endothelial nitric oxide synthase in red blood cells: key to a new erythrocrine function?

Red blood cells (RBC) have been considered almost exclusively as a transporter of metabolic gases and nutrients for the tissues. It is an accepted dogma that RBCs take up and inactivate endothelium-derived NO via rapid reaction with oxyhemoglobin to form methemoglobin and nitrate, thereby limiting NO available for vasodilatation. Yet it has also been shown that RBCs not only act as "NO sinks", but exert an erythrocrine function - i.e an endocrine function of RBC - by synthesizing, transporting and releasing NO metabolic products and ATP, thereby potentially controlling systemic NO bioavailability and vascular tone. Recent work from our and others laboratory demonstrated that human RBCs carry an active type 3, endothelial NO synthase (eNOS), constitutively producing NO under normoxic conditions, the activity of which is compromised in patients with coronary artery disease. In this review we aim to discuss the potential role of red cell eNOS in RBC signaling and function, and to critically revise evidence to this date showing a role of non-endothelial circulating eNOS in cardiovascular pathophysiology.

Lipid pools as photolabile "protecting groups": design of light-activatable bioagents

Inactive in the membrane: Lipidated light-responsive constructs that sequester bioagents (R, see scheme) to the membranes of organelles and cells have been constructed. When membrane-bound, the bioagent is not susceptible to processing by its biological target. Photolysis releases the bioagent from its membrane anchor and thereby renders it biologically active.