Clinical characteristics and early prediction of mortality risk in patients with acute organophosphate poisoning-induced shock

Objective

To further get insights of clinical characteristics of acute organophosphate poisoning-induced shock, investigate the relationship between shock and prognosis, and screen risk indicators for prognosis.

Methods

A total of 73 patients with acute organophosphate poisoning admitted to our hospital between January 2014 and December 2021 were enrolled in this retrospective study. Patients were divided into the shock group and the non-shock group. The pH value of blood, arterial blood carbon dioxide partial pressure (PaCO₂), arterial partial pressure of oxygen (PaO₂), base excess (BE), lactic acid (Lac), serum albumin (ALB), total bilirubin (TBIL), alanine aminotransferase (ALT), serum creatinine (Cr), serum potassium (K), serum calcium (Ca), serum sodium (Na), blood chloride (Cl), serum troponin I (cTNI), brain natriuretic peptide (BNP), white blood cell count (WBC), hemoglobin (HGB), platelet count (PLT), and other clinical indicators of patients were recorded. Incidence of shock, time of shock onset, and outcomes of patients were also recorded. Cox proportional hazards regression models were performed for analysis.

Results

The incidence of organophosphate poisoning-induced shock was 30.1% (22/73), and 72.7% of shock patients developed shock blood pressure within 6 h. The levels of blood lactate, ALT, Cr, cTNI, BNP, and Cl in the shock group were significantly higher than those in the non-shock group, while the level of Ca and pH value was significantly lower than that in the non-shock group (all p < 0.05). Moreover, compared with patients without shock (2.0%), the mortality rate was significantly increased in patients with shock (36.4%), which was supported by the results from adjusted Cox proportional hazards regression model. We found that shock and elevated serum creatinine were associated with increased risk of death in patients with organophosphate poisoning (shock: HR, 10.9; 95% CI 1.2-96.3; elevated serum creatinine: HR, 1.0, 95% CI 1.0-1.0).

Conclusion

This study indicated the association between elevated serum creatinine and increased mortality rates in patients with organophosphate poisoning, highlighting the importance of the comprehensive management of shock, especially the control of renal function, in these poisoning patients.

Histopathological features of low-dose organophosphate exposure

Organophosphate (OP) use remains largely available worldwide despite more strict regulatory measures, in agriculture, parks or households, leading to a daily low-dose exposure. The systemic dysfunction appears partly due to acetylcholinesterase inhibition, exhibiting a primary toxic effect on the endocrine system but also on the liver and kidneys, which are responsible for products metabolization and elimination. Prolonged OP exposure can be responsible for histopathological (HP) changes that can either evolve or worsen pre-existing conditions. We conducted an experimental study including six male Wistar rats divided into two groups (four rats in the study group and two in the control group). The subjects in the first group were administered 100 mg/kg Chlorpyrifos half median lethal dose (LD₅₀) at baseline and at 48 hours, under general anesthesia. Organ harvesting was achieved after one week. HP modifications were discovered in all kidney samples, with dystrophic changes and vacuolization of mesangial cells, dilation of renal tubules and epithelial atrophy. Congestion of vascular structures also occurred. The liver samples showed severe alteration in both vessels and hepatocytes. Adrenal gland impairment was confirmed through an increase in vacuole number in all areas, while a decrease in colloid content was noted in the thyroid gland simultaneously with a modified foamy aspect. This study is the first to certify the extent of organ injury induced by OP exposure, describing both glomerular and tubular involvement in the kidneys, liver necrosis and endocrine disturbances.

Ameliorative effects of jamun seed and orange peel extracts on microcystin LR induced alterations in calcitonin cells and parathyroid gland of rats

This study investigated changes in calcitonin cells (C-cells) and parathyroid glands (PTG) induced by microcystin LR (MCLR) exposure to rats and evaluated ameliorative effects of jamun (Syzygium cumini) seed (JSE) and orange (Citrus sinensis) peel (OPE) extracts. Wistar rats were treated as-Group A (control), Group B (MCLR), Group C (MCLR + JSE), Group D (MCLT + OPE), Group E (OPE) and Group F (JSE). Microcystin dose was (10 μg/kg body wt/day whereas OPE and JSE dose was 200 mg/kg body wt/day. Thyroid and PTG were fixed on 15 and 30 days following the treatment. C-cells of treated rats for 15 days with MCLR; MCLR + JSE and MCLR + OPE exhibit degranulation, mitochondrial swelling and prominent RER. In MCLR treated rats few cells completely lack secretory granules. After 30 days MCLR treatment accumulation of secretory granules and degeneration were noticed in C-cells. C-cell nuclear volume (NV) of MCLR, MCLR + JSE and MCLT + OPE treated rats show an increase. In MCLR, MCLR + JSE and MCLR + OPE treated rats PTG exhibit hyperchromatic nuclei, nuclear elongation and increased NV after 15 days. After 30 days MCLR treatment nuclei of PTG become more hyperchromatic, more elongated, show degeneration of nuclei and increase in NV. NV is increased in Group C and Group D. PTG remain unaltered 30 days following treatment with OPE and JSE. Microcystin LR provoke physiological effects on the blood calcium and alterations in C cells and PTG, which cause serious threat to organism. These changes can be protected by JSE and OPE.

A novel rat model of vitamin D deficiency: safe and rapid induction of vitamin D and calcitriol deficiency without hyperparathyroidism

Vitamin D deficiency is associated with a range of clinical disorders. To study the mechanisms involved and improve treatments, animal models are tremendously useful. Current vitamin D deficient rat models have important practical limitations, including time requirements when using, exclusively, a vitamin D deficient diet. More importantly, induction of hypovitaminosis D causes significant fluctuations in parathyroid hormone (PTH) and mineral levels, complicating the interpretation of study results. To overcome these shortcomings, we report the successful induction of vitamin D deficiency within three weeks, with stable serum PTH and minerals levels, in Wistar rats. We incorporated two additional manoeuvres compared to a conventional diet. Firstly, the vitamin D depleted diet is calcium (Ca) enriched, to attenuate the development of secondary hyperparathyroidism. Secondly, six intraperitoneal injections of paricalcitol during the first two weeks are given to induce the rapid degradation of circulating vitamin D metabolites. After three weeks, serum 25-hydroxyvitamin D3 (25D) and 1,25-dihydroxyvitamin D3 (1,25D) levels had dropped below detection limits, with unchanged serum PTH, Ca, and phosphate (P) levels. Therefore, this model provides a useful tool to examine the sole effect of hypovitaminosis D, in a wide range of research settings, without confounding changes in PTH, Ca, and P.

Paraoxonase enzyme protects retinal pigment epithelium from chlorpyrifos insult

Retinal pigment epithelium (RPE) provides nourishment and protection to the eye. RPE dysfunction due to oxidative stress and inflammation is one of the major reason for many of the retinal disorders. Organophosphorus pesticides are widely used in the agricultural, industrial and household activities in India. However, their effects on the eye in the context of RPE has not been studied. In this study the defense of the ARPE19 cells exposed to Chlorpyrifos (1 nM to 100 µM) in terms of the enzyme paraoxonase (PON) was studied at 24 hr and 9 days of treatment. Chlorpyrifos was found to induce oxidative stress in the ARPE19 cells as seen by significant increase in ROS and decrease in glutathione (GSH) levels without causing cell death. Tissue resident Paraoxonase 2 (PON2) mRNA expression was elevated with chlorpyrifos exposure. The three enzymatic activities of PON namely, paraoxonase (PONase), arylesterase (PON AREase) and thiolactonase (PON HCTLase) were also found to be significantly altered to detoxify and as an antioxidant defense. Among the transcription factors regulating PON2 expression, SP1 was significantly increased with chlorpyrifos exposure. PON2 expression was found to be crucial as ARPE19 cells showed a significant loss in their ability to withstand oxidative stress when the cells were subjected to chlorpyrifos after silencing PON2 expression. Treatment with N-acetyl cysteine positively regulated the PON 2 expression, thus promoting the antioxidant defense put up by the cells in response to chlorpyrifos.