Lasalocid E

Lasalocid, a specific mobile membrane ionophore for calcium, dopamine and norepinephrine was assayed in its capacity to reduce or maintain unaltered the cardiovascular function in conditions of imminent myocardial injury. In experiments of coronary blockade and reperfusion carried out in rat heart, it was found that when administered from 5 to 30 minutes prior to the induction of coronary blockade, at a concentration of 2 mg/kg of body weight, the ionophore immediately, simultaneously, and completely interrupts the blood pressure decay, cardiac frequency increase, electrical ventricular tachycardia and fibrillation, as well as the fall of mitochondrial oxidative phosphorylation and decay of mitochondrial oxygen uptake provoked by the induced myocardial injury. It appears that the molecular mode of action of the lasalocid is associated with its unique ability to transport both calcium and the catecholamines, dopamine and norepinephrine, across mitochondrial and bimolecular lipid membranes, as well as through synaptic cell membrane terminals from rat heart, myocardial fibers of the heart and heart chromaffin membrane vesicles. It is suggested that for the potential medical use of lasalocid to detain incoming ischemic myocardial damage, there exists a need to develop a personal electronic device able to simultaneously monitor, detect, and inform on the very early and simultaneous signs of cardiac alterations of electrical, mechano-chemical, metabolic and hydraulic nature, all which precede heart failure and to administer the lasalocid.

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the coccidiostat Nilablend™ 200G containing lasalocid A sodium and nicarbazin. Nilablend™ 200G is not safe for chickens for fattening at the proposed maximum use level of 50 mg lasalocid A sodium + 50 mg nicarbazin/kg complete feed. Concurrent administration of Nilablend™ 200G (containing lasalocid A sodium) with tiamulin and certain other medicinal substances should be avoided. Lasalocid A sodium has antimicrobial activity against Gram-positive bacterial species while many Enterobacteriaceae are naturally resistant. Induction of resistance and/or cross-resistance was not observed in experimental conditions. No information on the interactions of nicarbazin with feed materials, other approved additives or medicinal products have been provided. No data were submitted on the microbiological safety of nicarbazin. The toxicological package for lasalocid A sodium and nicarbazin identified no observed adverse effect levels (NOAELs) that could be the basis for setting health-based guidance values (e.g. an acceptable daily intake (ADI)). The Panel concluded that a concern for the genotoxicity of nicarbazin in Nilablend™ 200G cannot be excluded and that clarification on the mechanism of action of the test items would be needed. Therefore, the FEEDAP Panel is not in the position to establish an ADI for DNC on which to base the assessment of consumer safety. Nilablend™ 200G is considered toxic by inhalation, corrosive and irritant to eyes, slightly irritant to the skin but not a skin sensitiser. Inhalation exposure is considered a risk to persons handling the additive. The FEEDAP Panel cannot conclude on the safety of Nilablend™ 200G for the environment due to a possible risk for aquatic compartment (freshwater) for DNC. The efficacy of Nilablend® 200G was demonstrated.

The ionophore lasalocid is widely used as a veterinary drug against coccidiosis. We found recently that lasalocid protects cells from two unrelated bacterial toxins, the cytotoxic necrotizing factor-1 (CNF1) from Escherichia. coli and diphtheria toxin. We evaluated lasalocid's capacity to protect cells against other toxins of medical interest comprising toxin B from Clostridium difficile, Shiga-like toxin 1 from enterohemorrhagic E. coli and exotoxin A from Pseudomonas aeruginosa. We further characterized the impact of lasalocid on the endolysosomal and the retrograde pathways and organelle integrity, especially the Golgi apparatus. We found that lasalocid protects cells from all toxins tested and impairs the drop of vesicular pH along the trafficking pathways that are required for toxin sorting and translocation to the cytoplasm. Lasalocid also has an impact on the cellular distribution of GOLPH4 and GOLPH2 Golgi markers. Other intracellular trafficking compartments positive for EEA1 and Rab9A display a modified cellular pattern. In conclusion, lasalocid protects cells from multiple deadly bacterial toxins by corrupting vesicular trafficking and Golgi stack homeostasis.