Effect of Crotalus oreganus Derived Crotamine on Lymphatic Endothelial Cells and Lymph Transport

The pathology of many snake bites is closely tied the severity of edema in the tissue surrounding the snake bite. Elucidating the mechanisms that promote the development of such severe edema is critical to a better understanding of how to treat this expensive and potentially life‐threatening injury. To that end we have examined one of the most common toxins in North American viper venom, Crotamine. Crotamine has been associated with myotoxic effects and effects on the nervous system but the role this toxin my play in the development of edema, particularly it’s role in lymphatic dysfunction is unknown. The lymphatic system removes fluids, solutes and cells from the tissue and is a potential target tissue for snake venom as it is the likely route of transport for venom components. Methods/Results We have described the presence of crotamine cellular targets (Kvα channels) within the tissues and cells of the lymphatic system via RT‐PCR, as well as the effects (biochemical and physiological) it has on those tissues. We found that genes that encode targets of crotamine are highly present in lymphatic tissues and cells and that there is a differential distribution of those genes that correlates with phasic contractile activity. However, there is significant expression of the Kv channels in the lymphatic endothelium suggesting that there may be multiple effects of crotamine depending upon where a vessel is exposed to crotamine. We found that crotamine potentiates calcium flux, as determined by Fura‐2 imaging, in human dermal lymphatic endothelial cells in response to stimulation with histamine (a common mediator released after snake bite), and sheer. Additionally, it alters the production of nitric oxide in response to sheer in lymphatic endothelial cells as well as changes the level of F‐actin polymerization of those same cells. Crotamine also alters lymphatic transport of large molecular weight tracers (70kDa FITC‐Dextran) to local lymph nodes and is deposited within the node. Conclusions This evidence suggests that snake venom components may have an impact on the function of the lymphatic system. This needs to be studied in greater detail as there are numerous venom components that may have an effect on aspects of the lymphatic system. This would not only provide basic information on the pathobiology of snake bite but also provide targets for improved therapeutics to treat snakebite. Support or Funding Information NASA Grant Number 80NSSC19K0438 (Cromer), The Lipedema Foundation NLF#11 (Cromer), the NTRC (Sanchez), NIH U01 5U01HL123420‐05 (Zawieja)