In vitro Evaluation of Programmed Cell Death in the Immune System of Pacific Oyster Crassostrea gigas by the Effect of Marine Toxins.

Programmed cell death (PCD) is an essential process for the immune system's development and homeostasis, enabling the remotion of infected or unnecessary cells. There are several PCD's types, depending on the molecular mechanisms, such as non-inflammatory or pro-inflammatory. Hemocytes are the main component of cellular immunity in bivalve mollusks. Numerous infectious microorganisms produce toxins that impair hemocytes functions, but there is little knowledge on the role of PCD in these cells. This study aims to evaluate in vitro whether marine toxins induce a particular type of PCD in hemocytes of the bivalve mollusk Crassostrea gigas during 4 h at 25°C. Hemocytes were incubated with two types of marine toxins: non-proteinaceous toxins from microalgae (saxitoxin, STX; gonyautoxins 2 and 3, GTX2/3; okadaic acid/dynophysistoxin-1, OA/DTX-1; brevetoxins 2 and 3, PbTx-2,-3; brevetoxin 2, PbTx-2), and proteinaceous extracts from bacteria (Vibrio parahaemolyticus, Vp; V. campbellii, Vc). Also, we used the apoptosis inducers, staurosporine (STP), and camptothecin (CPT). STP, CPT, STX, and GTX 2/3, provoked high hemocyte mortality characterized by apoptosis hallmarks such as phosphatidylserine translocation into the outer leaflet of the cell membrane, exacerbated chromatin condensation, DNA oligonucleosomal fragments, and variation in gene expression levels of apoptotic caspases 2, 3, 7, and 8. The mixture of PbTx-2,-3 also showed many apoptosis features; however, they did not show apoptotic DNA oligonucleosomal fragments. Likewise, PbTx-2, OA/DTX-1, and proteinaceous extracts from bacteria Vp, and Vc, induced a minor degree of cell death with high gene expression of the pro-inflammatory initiator caspase-1, which could indicate a process of pyroptosis-like PCD. Hemocytes could carry out both PCD types simultaneously. Therefore, marine toxins trigger PCD's signaling pathways in C. gigas hemocytes, depending on the toxin's nature, which appears to be highly conserved both structurally and functionally.

Myeloperoxidase enzymatic activity is increased in patients with different levels of dental crowding after initial orthodontic activation.

INTRODUCTION: Orthodontic tooth movement implies application of forces that generate an inflammatory process. The myeloperoxidase (MPO) enzyme is found inside neutrophil granules. MPO activity indirectly reflects the level of inflammation. The aim of this study was to measure MPO activity in gingival crevicular fluid (GCF) and whole saliva in orthodontic patients with different levels of dental crowding at the alignment phase of orthodontic treatment with the same archwires. METHODS: Twenty patients were classified according to the irregularity index into 2 groups: severe and minimum crowding (10 in each group). MPO activity was evaluated in GCF and saliva at 0 and 2 hours, and 7 and 14 days after the orthodontic appliances were activated. MPO activity was measured using the modified Bradley-Bozeman technique. RESULTS: In both groups, the maximum activity was at 2 hours (P <0.05) after activation. MPO activity remained elevated until day 7, and values similar to baseline were found at day 14 in the GCF and saliva samples. Enzymatic activity did not show statistical differences between the groups. CONCLUSIONS: The amount of dental crowding does not seem to influence MPO activity, which showed similar patterns in GCF and saliva, but the values in GCF reflected the inflammatory changes more accurately than did the values in saliva. The quantification of MPO activity is a useful biologic marker as an indirect measurement of inflammation generated with tooth movement independent of the amount of crowding.