The Organophosphate Paraoxon and Its Antidote Obidoxime Inhibit Thrombin Activity and Affect Coagulation In Vitro

Aryl Organophosphate Esters and Hemostatic Disruption: Identifying Risk through Machine Learning and Experimental Validation

Organophosphate esters (OPEs) have emerged as a significant environmental concern due to their widespread occurrence and potential human health risks. The presence of OPEs in human blood suggests direct interactions with hematological components, which may compromise hemostatic balance and lead to adverse health outcomes. Despite the critical role of hemostatic balance in maintaining blood stability, the effects of OPEs on this system remain poorly understood. This investigation was undertaken to delineate the effects and potential mechanisms of OPEs that modulate hemostasis, utilizing in silico approach and high-throughput in vitro investigation. We analyzed 85 environmentally prevalent OPEs for their structural descriptors and affinity for proteins essential to hemostatic function. The multiple linear regression implicated aryl-OPEs, distinguished by their benzene ring scaffold, as potent disruptors of hemostatic balance. This analysis result was rigorously validated through the in vitro hemostatic balance assays. Further investigation through network toxicology, artificial intelligence (α-Fold) algorithms, and an agonist cotreatment assay revealed proliferator-activated receptor γ (PPARγ) as a key mediator of aryl-OPEs induced hemostatic disruption. By integrating in vitro experimental insights with in vivo exposure data, we concluded that specific aryl-OPEs, such as bisphenol a bis (diphenyl phosphate) (BDP) and cresyl diphenyl phosphate (CDP), pose a moderate risk to the hemostatic balance of the general population. Our findings not only contribute to the prioritization of OPEs risk management but also establish a methodology for assessing the hematological toxicity of emerging pollutants.

Cognitive and Cellular Effects of Combined Organophosphate Toxicity and Mild Traumatic Brain Injury

Traumatic brain injury (TBI) is considered the most common neurological disorder among people under the age of 50. In modern combat zones, a combination of TBI and organophosphates (OP) can cause both fatal and long-term effects on the brain. We utilized a mouse closed-head TBI model induced by a weight drop device, along with OP exposure to paraoxon. Spatial and visual memory as well as neuron loss and reactive astrocytosis were measured 30 days after exposure to mild TBI (mTBI) and/or paraoxon. Molecular and cellular changes were assessed in the temporal cortex and hippocampus. Cognitive and behavioral deficits were most pronounced in animals that received a combination of paraoxon exposure and mTBI, suggesting an additive effect of the insults. Neuron survival was reduced in proximity to the injury site after exposure to paraoxon with or without mTBI, whereas in the dentate gyrus hilus, cell survival was only reduced in mice exposed to paraoxon prior to sustaining a mTBI. Neuroinflammation was increased in the dentate gyrus in all groups exposed to mTBI and/or to paraoxon. Astrocyte morphology was significantly changed in mice exposed to paraoxon prior to sustaining an mTBI. These results provide further support for assumptions concerning the effects of OP exposure following the Gulf War. This study reveals additional insights into the potentially additive effects of OP exposure and mTBI, which may result in more severe brain damage on the modern battlefield.

Does skeletal muscle morphology or functional performance better explain variance in fast gait speed in older adults?

BACKGROUND

Fast gait speed is being increasingly recognized as an important clinical tool in older adults. However, the underlying muscular and functional contributors to fast gait speed performance remain poorly understood.

AIM

We sought to determine predictors of fast gait speed in older adults. We hypothesized that lower-extremity skeletal muscle size and quality would be strong predictors.

METHODS

Ninety community-dwelling older adults (33 men, 57 women; mean ± SD age = 74 ± 6 years) participated. B-mode ultrasonography was used to capture images of the vastus lateralis, rectus femoris, and gastrocnemius in the transverse plane. Each participant performed 30-second chair stand, heel-rise, functional reach, and grip strength tests. Fast gait speed was measured using the NIH Toolbox 4-Meter Walk Test. ImageJ software was used to quantify cross-sectional area (CSA), subcutaneous tissue thickness, and echo intensity. Two separate stepwise regression analyses were performed, one using muscle morphology variables as independent variables, and another including the functional outcomes.

RESULTS

The ultrasound variables exhibited weak-to-moderate correlations with fast gait speed (|r| range = 0.168-0.416). The initial regression analysis indicated that the combination of medial gastrocnemius CSA and subcutaneous tissue thickness explained 22.8% of the variance in fast gait speed. The secondary analysis indicated that 30-second chair stand, heel-rise, and grip strength performance explained 45.5% of the variance.

CONCLUSION

While medial gastrocnemius morphology is important, measures of upper and lower-extremity muscle function are better predictors of fast gait speed. These results highlight a dissociation between skeletal muscle morphology and fast gait speed.

An Appraisal of Antidotes' Effectiveness: Evidence of the Use of Phyto-Antidotes and Biotechnological Advancements

Poisoning is the greatest source of avoidable death in the world and can result from industrial exhausts, incessant bush burning, drug overdose, accidental toxication or snake envenomation. Since the advent of Albert Calmette’s cobra venom antidote, efforts have been geared towards antidotes development for various poisons to date. While there are resources and facilities to tackle poisoning in urban areas, rural areas and developing countries are challenged with poisoning management due to either the absence of or inadequate facilities and this has paved the way for phyto-antidotes, some of which have been scientifically validated. This review presents the scope of antidotes’ effectiveness in different experimental models and biotechnological advancements in antidote research for future applications. While pockets of evidence of the effectiveness of antidotes exist in vitro and in vivo with ample biotechnological developments, the utilization of analytic assays on existing and newly developed antidotes that have surpassed the proof of concept stage, as well as the inclusion of antidote’s short and long-term risk assessment report, will help in providing the required scientific evidence(s) prior to regulatory authorities’ approval.

Pulmonary thrombosis in acute organophosphate poisoning-Case report and literature overview of prothrombotic preconditioning in organophosphate toxicity

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Acute OP poisoning complicated with pulmonary thrombosis during the first week of poisoning.

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Antidote treatment included atropine, whereas diazepam was administered in the first 48 h.

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There was no administration of oximes due to unavailability.

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Prolonged hypoxemia in acute OP intoxication indicates exclusion of thrombotic pulmonary event.

Objective

Acute organophosphate (OP) poisonings are presented with acetylcholine-receptor overstimulation. There have been a few case reports of thrombotic complications in acute OP poisonings, as well as prolonged thrombosis preconditions in patients who survived this type of intoxications. The paper presents a case with pulmonary thrombosis (PT) that develops in the subacute phase of intentional acute OP poisoning, treated only with atropine, as well as a literature overview of OP-induced prothrombotic toxicity.

Case report

A middle aged woman was brought to the hospital after ingestion of unknown insecticide with suicidal intentions. She had a history of HTA (arterial hypertension), hyperlipidemia and untreated depression. The clinical features of poisoning were miosis, vomiting, dizziness, abdominal cramps and diarrhea. Soon after admission, she developed difficulties in breathing with decrease of serum pseudocholinesterase (2590...1769...1644...800 U/l), bibasal pulmonary crackles, drop of SpO₂ to 84%. Antidote treatment included carbo medicinalis, atropine, and diazepam, without use of oximes. The seventh day pseudocholinesterase, the levels started to rise but the patient’s hyposaturation (SpO₂ 86-88%) persisted. Chest ultrasound detected hypoechoic subpleural lesion to the right. Haemostatic tests showed increased D-Dimmer (2312 ng/ml) with hypercoagulability. The CT pulmonary angiography confirmed PT and after the administration of low molecular heparin, her clinical condition improved.

Conclusion

Acute organophosphate poisoning treated with atropine showed a potential for inducing prothrombotic coagulation abnormalities, presented with PT. This life-threatening complication may additionally contribute to prolonged morbidity and mortality in OP poisonings, especially in patients with medical history of comorbidites.

Time dependent dual effect of anti-inflammatory treatments on sarin-induced brain inflammation: Suggested role of prostaglandins

A common consequence of exposure to organophosphate nerve agents is the centrally mediated seizure activity that appears even after conventional treatment with atropine and oximes. We have previously demonstrated a major inflammatory response with subsequent brain damage which was correlated with the duration of the sarin-induced seizures (Chapman et al., 2006). In the present work seizures were induced by the nerve agent sarin (1.2 LD50) insufficiently treated 1 min later by atropine and trimedoxime bromide (TA), with additional midazolam treatment either 5 or 30 min after continuous seizure activity. The efficacy of both steroidal and nonsteroidal anti-inflammatory drugs (NSAIDs), as well as other drugs that were reported as beneficial in neuroprotection, were evaluated for their contribution as adjunct treatment against sarin induced seizures and the ensuing inflammatory brain damage. Results show that both steroids and NSAIDs were harmful when administered during convulsions, and steroids were at best ineffective if administered at their termination. However, if administered at termination of convulsions, the NSAID ibuprofen, the selective COX 2 inhibitor nimesulide and the PLA2 inhibitor quinacrine were partially effective in reducing brain inflammatory markers. Administration of exogenous analogs of prostaglandins (PGE2) immediately following sarin-induced convulsions was found to have a beneficial effect in reducing brain inflammatory markers measured at 24 h and one week post sarin exposure. These findings support the hypothesis that elevated levels of PGE2 have a beneficial role immediately following sarin induced seizures, and that early inhibition of PGE2 production by both steroids and NSAID is contraindicative.

Thrombin and the Protease-Activated Receptor-1 in Organophosphate-Induced Status Epilepticus

Organophosphates (OP) are a major threat to the health of soldiers and civilians due to their use as chemical weapons in war and in terror attacks. Among the acute manifestations of OP poisoning, status epilepticus (SE) is bearing the highest potential for long-term damages. Current therapies do not prevent brain damage and seizure-related brain injuries in OP-exposed humans. Thrombin is a serine protease known to have a fundamental function in the clotting cascade. It is highly expressed in the brain where we have previously found that it regulates synaptic transmission and plasticity. In addition, we have found that an excess of thrombin in the brain leads to hyperexcitability and therefore seizures through a glutamate-dependent mechanism. In the current study, we carried out in vitro, ex vivo, and in vivo experiments in order to determine the role of thrombin and its receptor PAR-1 in paraoxon-induced SE. Elevated thrombin activity was found in the brain slices from mice that were treated (in vitro and in vivo) with paraoxon. Increased levels of PAR-1 and pERK proteins and decreased prothrombin mRNA were found in the brains of paraoxon-treated mice. Furthermore, ex vivo and in vivo electrophysiological experiments showed that exposure to paraoxon causes elevated electrical activity in CA1 and CA3 regions of the hippocampus. Moreover, a specific PAR-1 antagonist (SCH79797) reduced this activity. Altogether, these results reveal the importance of thrombin and PAR-1 in paraoxon poisoning. In addition, the results indicate that thrombin and PAR-1 may be a possible target for the treatment of paraoxon-induced status epilepticus.