Dysregulation of apoptosis in scorpion envenomed children: its reflection on their outcome

Abstract

In the present study, 46 children in Upper Egypt (less than 13 years old) were admitted to the Pediatric Intensive Care Unit for scorpion envenomation. They were compared with 20 apparently healthy children of matching age and sex as controls. Out of the studied victims, 25 children (54%) showed signs of severe envenomation and multiple organ dysfunction (MOD), while 21 victims (46%) showed signs of mild envenomation. The serum levels of apoptotic markers, soluble Fas (sFas), soluble Fas ligand (sFasL) and Bcl-2, were determined for both victims and controls. In addition, the serum levels of nitric oxide (NO) and lipid peroxides (LPO) were also measured. Scoring of MOD was evaluated using Logistic Organ Dysfunction System Score (LODS) for the severely envenomed victims. All victims (both severe and mild cases) showed significantly higher mean levels of sFas, LPO and NO and significantly lower serum levels of Bcl-2 in comparison to the controls. The level of sFasL was not detectable in the sera of the healthy control group. The case fatality rate was 15%. The severely envenomed children with MOD as well as the non-survivors showed significantly higher serum levels of sFas, sFasL, LPO and NO and significantly lower serum levels of Bcl-2 in comparison to the mild envenomed victims and the surviving victims of severe cases, respectively. The LODS score of the severely envenomed victims showed significant positive correlations with sFas and LPO and significant negative correlation with Bcl-2. In all victims, a significant positive correlation was detected between sFas and NO. On the other hand, Bcl-2 was significantly negatively correlated with both sFas and LPO. In conclusion, our study revealed that scorpion envenomation can increase apoptosis as shown by up-regulation of sFas/sFasL system and down-regulation of Bcl-2 that was associated by elevation of LPO and NO. This dysregulation of apoptosis was increased with the severity of scorpion envenomation and its extent increased as MOD score and outcome increased. Therefore, sFas and Bcl-2 may be of value in predicting the outcome of these cases. The increase of the extent of apoptosis detected in this study seems to play a role in the outcome of scorpion envenomation, and hence, should be taken into consideration for strategies of therapeutic regimen.